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Sample records for maximal pressure overload

  1. Intermittent cardiac overload results in adaptive hypertrophy and provides protection against left ventricular acute pressure overload insult.

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    Moreira-Gonçalves, Daniel; Henriques-Coelho, Tiago; Fonseca, Hélder; Ferreira, Rita; Padrão, Ana Isabel; Santa, Cátia; Vieira, Sara; Silva, Ana Filipa; Amado, Francisco; Leite-Moreira, Adelino; Duarte, José Alberto

    2015-09-01

    The present study aimed to test whether a chronic intermittent workload could induce an adaptive cardiac phenotype Chronic intermittent workload induced features of adaptive hypertrophy This was paralleled by protection against acute pressure overload insult The heart may adapt favourably to balanced demands, regardless of the nature of the stimuli. The present study aimed to test whether submitting the healthy heart to intermittent and tolerable amounts of workload, independently of its nature, could result in an adaptive cardiac phenotype. Male Wistar rats were subjected to treadmill running (Ex) (n = 20), intermittent cardiac overload with dobutamine (ITO) (2 mg kg(-1) , s.c.; n = 20) or placebo administration (Cont) (n = 20) for 5 days week(-1) for 8 weeks. Animals were then killed for histological and biochemical analysis or subjected to left ventricular haemodynamic evaluation under baseline conditions, in response to isovolumetric contractions and to sustained LV acute pressure overload (35% increase in peak systolic pressure maintained for 2 h). Baseline cardiac function was enhanced only in Ex, whereas the response to isovolumetric heartbeats was improved in both ITO and Ex. By contrast to the Cont group, in which rats developed diastolic dysfunction with sustained acute pressure overload, ITO and Ex showed increased tolerance to this stress test. Both ITO and Ex developed cardiomyocyte hypertrophy without fibrosis, no overexpression of osteopontin-1 or β-myosin heavy chain, and increased expression of sarcoplasmic reticulum Ca(2+) protein. Regarding hypertrophic pathways, ITO and Ex showed activation of the protein kinase B/mammalian target of rapamycin pathway but not calcineurin. Mitochondrial complex IV and V activities were also increased in ITO and Ex. Chronic submission to controlled intermittent cardiac overload, independently of its nature, results in an adaptive cardiac phenotype. Features of the cardiac overload, such as the duration and

  2. Altered carnitine transport in pressure-overload hypertrophied rat hearts

    International Nuclear Information System (INIS)

    O'Rourke, B.; Foster, K.; Reibel, D.K.

    1986-01-01

    The authors have previously observed reduced carnitine levels in hypertrophied hearts of rats subjected to aortic constriction. In an attempt to determine the mechanism for reduced myocardial carnitine content, carnitine transport was examined in isolated perfused hearts. Hearts were excised from sham-operated and aortic-constricted rats 3 weeks following surgery and perfused at 60 mm Hg aortic pressure with buffer containing various concentrations of L- 14 C-carnitine. Carnitine uptake by control and hypertrophied hearts was linear throughout 30 minutes of perfusion with 40 μM carnitine. Total carnitine uptake was significantly reduced by 25% in hypertrophied hearts at each time point examined. The reduction in uptake by hypertrophied hearts was also evident when hearts were perfused with 100 or 200 μM carnitine. When 0.05 mM mersalyl acid was included in the buffer to inhibit the carrier-mediated component of transport, no difference in carnitine uptake was observed indicating that the transport of carnitine by diffusion was unaltered in the hypertrophied myocardium. Carrier-mediated carnitine uptake (total uptake - uptake by diffusion) was significantly reduced by approximately 40% in hypertrophied hearts at all concentrations examined. Thus, the reduction in carnitine content in the pressure-overload hypertrophied rat heart appears to be due to a reduction in carrier-mediated carnitine uptake by the heart

  3. The role of adenosine in preconditioning by brief pressure overload in rats.

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    Huang, Cheng-Hsiung; Tsai, Shen-Kou; Chiang, Shu-Chiung; Lai, Chang-Chi; Weng, Zen-Chung

    2015-08-01

    Brief pressure overload of the left ventricle reduced myocardial infarct (MI) size in rabbits has been previously reported. Its effects in other species are not known. This study investigates effects of pressure overload and the role of adenosine in rats in this study. MI was induced by 40-minute occlusion of the left anterior descending coronary artery followed by 3-hour reperfusion. MI size was determined by triphenyl tetrazolium chloride staining. Brief pressure overload was induced by two 10-minute episodes of partial snaring of the ascending aorta. Systolic left ventricular pressure was raised 50% above the baseline value. Ischemic preconditioning was elicited by two 10-minute coronary artery occlusions. The MI size (mean ± standard deviation), expressed as percentage of area at risk, was significantly reduced in the pressure overload group as well as in the ischemic preconditioning group (17.4 ± 3.0% and 18.2 ± 1.5% vs. 26.6 ± 2.4% in the control group, p overload and ischemic preconditioning (18.3 ± 1.5% and 18.2 ± 2.0%, respectively, p overload of the left ventricle preconditioned rat myocardium against infarction. Because SPT did not significantly alter MI size reduction, our results did not support a role of adenosine in preconditioning by pressure overload in rats. Copyright © 2013. Published by Elsevier B.V.

  4. In vivo cardiac role of migfilin during experimental pressure overload.

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    Haubner, Bernhard Johannes; Moik, Daniel; Schuetz, Thomas; Reiner, Martin F; Voelkl, Jakob G; Streil, Katrin; Bader, Kerstin; Zhao, Lei; Scheu, Claudia; Mair, Johannes; Pachinger, Otmar; Metzler, Bernhard

    2015-06-01

    Increased myocardial wall strain triggers the cardiac hypertrophic response by increasing cardiomyocyte size, reprogramming gene expression, and enhancing contractile protein synthesis. The LIM protein, migfilin, is a cytoskeleton-associated protein that was found to translocate in vitro into the nucleus in a Ca(2+)-dependent manner, where it co-activates the pivotal cardiac transcription factor Csx/Nkx2.5. However, the in vivo role of migfilin in cardiac function and stress response is unclear. To define the role of migfilin in cardiac hypertrophy, we induced hypertension by transverse aortic constriction (TAC) and compared cardiac morphology and function of migfilin knockout (KO) with wild-type (WT) hearts. Heart size and myocardial contractility were comparable in untreated migfilin KO and WT hearts, but migfilin-null hearts presented a reduced extent of hypertrophic remodelling in response to chronic hypertensile stress. Migfilin KO mice maintained their cardiac function for a longer time period compared with WT mice, which presented extensive fibrosis and death due to heart failure. Migfilin translocated into the nucleus of TAC-treated cardiomyocytes, and migfilin KO hearts showed reduced Akt activation during the early response to pressure overload. Our findings indicate an important role of migfilin in the regulation of cardiac hypertrophy upon experimental TAC. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  5. Role of electrocardiographic changes in discriminating acute or chronic right ventricular pressure overload.

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    Can, Mehmet Mustafa; Özveren, Olcay; Biteker, Murat; Şengül, Cihan; Uz, Ömer; Işılak, Zafer; Kırılmaz, Ata

    2013-06-01

    Pulmonary embolism (PE) and severe pulmonary stenosis (PS) are two distinct conditions accompanied by increased pressure load of the right ventricle (RV). Despite major advances in our understanding of the mechanisms of RV adaptation to the increased pressure, substantial gaps in our knowledge remain unsettled. One of much less known aspect of pressure overload of RV is its impact on electrocardiographic (ECG) changes. In this study, we aimed to study whether acute and chronic RV overload are accompanied by different ECG patterns. Thirty-eight patients with PE underwent ECG monitoring were compared with 20 matched patients with PS in this observational retrospective study. ECG abnormalities suggestive of RV overload were recorded and analyzed in both groups. Logistic regression analysis was used to define the predictors of chronic RV overload. Among the ECG changes studied, premature atrial contraction (OR-12.2, 95% CI, 1.3-107, p=0.008), right axis deviation (OR-20.4, 95% CI 4.2-98, poverload. Our data indicate that the ECG changes that attributed to the acute RV pressure loading states may be more prevalent in chronic RV overload as compared with acute RV overload.

  6. Reference Values for Maximal Inspiratory Pressure: A Systematic Review

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    Isabela MB Sclauser Pessoa

    2014-01-01

    Full Text Available BACKGROUND: Maximal inspiratory pressure (MIP is the most commonly used measure to evaluate inspiratory muscle strength. Normative values for MIP vary significantly among studies, which may reflect differences in participant demographics and technique of MIP measurement.

  7. Worse cardiac remodeling in response to pressure overload in type 2 diabetes mellitus.

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    Gonçalves, N; Gomes-Ferreira, C; Moura, C; Roncon-Albuquerque, R; Leite-Moreira, A F; Falcão-Pires, I

    2016-08-15

    Diabetic cardiomyopathy is characterized by cardiac structural and functional abnormalities. Additionally, chronic pressure overload conditions are highly prevalent amongst diabetic population and this association leads to a more severe myocardial impairment. The differences in myocardial pathophysiology between type 1 and type 2 diabetes mellitus (DM) still remain to be clarified. Thus, we aimed to investigate biventricular structural and functional changes promoted by the two types of DM and the impact of concomitant chronic pressure overload. Wistar rats were injected with streptozotocin (Type 1 DM, T1DM) or fed with a hypercaloric diet (Type 2 DM, T2DM). Pressure overload was imposed in DM animals by aortic constriction and after 5weeks of DM the cardiac function and structure were evaluated. Both types of DM promoted hypertrophy, increased fibrosis and advanced glycation end-products deposition, in the two ventricles. Interestingly, the induced myocardial alterations were distinct. While T1DM stimulated a pronounced hypertrophy and extracellular matrix remodeling, T2DM induced functional impairment. The negative impact of the association of DM with aortic constriction was more pronounced in T2DM, promoting impaired function and increased stiffness, particularly in the right ventricle. Our study demonstrated that the two types of diabetes induce distinct cardiac alterations per se or when combined with chronic pressure overload. T1DM promoted a more extensive remodeling in cardiac structure while T2DM significantly impaired ventricular function. The impact of pressure overload was more notorious in T2DM as observed by worse myocardial remodeling, suggesting a higher susceptibility to the deleterious effects of chronic pressure overload, namely hypertension, among this diabetic population. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Cold stress accentuates pressure overload-induced cardiac hypertrophy and contractile dysfunction: role of TRPV1/AMPK-mediated autophagy.

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    Lu, Songhe; Xu, Dezhong

    2013-12-06

    Severe cold exposure and pressure overload are both known to prompt oxidative stress and pathological alterations in the heart although the interplay between the two remains elusive. Transient receptor potential vanilloid 1 (TRPV1) is a nonselective cation channel activated in response to a variety of exogenous and endogenous physical and chemical stimuli including heat and capsaicin. The aim of this study was to examine the impact of cold exposure on pressure overload-induced cardiac pathological changes and the mechanism involved. Adult male C57 mice were subjected to abdominal aortic constriction (AAC) prior to exposure to cold temperature (4 °C) for 4 weeks. Cardiac geometry and function, levels of TRPV1, mitochondrial, and autophagy-associated proteins including AMPK, mTOR, LC3B, and P62 were evaluated. Sustained cold stress triggered cardiac hypertrophy, compromised depressed myocardial contractile capacity including lessened fractional shortening, peak shortening, and maximal velocity of shortening/relengthening, enhanced ROS production, and mitochondrial injury, the effects of which were negated by the TRPV1 antagonist SB366791. Western blot analysis revealed upregulated TRPV1 level and AMPK phosphorylation, enhanced ratio of LC3II/LC3I, and downregulated P62 following cold exposure. Cold exposure significantly augmented AAC-induced changes in TRPV1, phosphorylation of AMPK, LC3 isoform switch, and p62, the effects of which were negated by SB366791. In summary, these data suggest that cold exposure accentuates pressure overload-induced cardiac hypertrophy and contractile defect possibly through a TRPV1 and autophagy-dependent mechanism. Copyright © 2013. Published by Elsevier Inc.

  9. Vitamin D attenuates pressure overload-induced cardiac remodeling and dysfunction in mice.

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    Zhang, Liang; Yan, Xiao; Zhang, Yun-Long; Bai, Jie; Hidru, Tesfaldet Habtemariam; Wang, Qing-Shan; Li, Hui-Hua

    2018-04-01

    Vitamin D (VD) and its analogues play critical roles in metabolic and cardiovascular diseases. Recent studies have demonstrated that VD exerts a protective role in cardiovascular diseases. However, the beneficial effect of VD on pressure overload-induced cardiac remodeling and dysfunction and its underlying mechanisms are not fully elucidated. In this study, cardiac dysfunction and hypertrophic remodeling in mice were induced by pressure overload. Cardiac function was evaluated by echocardiography, and myocardial histology was detected by H&E and Masson's trichrome staining. Cardiomyocyte size was detected by wheat germ agglutinin staining. The protein levels of signaling mediators were examined by western blotting while mRNA expression of hypertrophic and fibrotic markers was examined by qPCR analysis. Oxidative stress was detected by dihydroethidine staining. Our results showed that administration of VD3 significantly ameliorates pressure overload-induced contractile dysfunction, cardiac hypertrophy, fibrosis and inflammation in mice. In addition, VD3 treatment also markedly inhibited cardiac oxidative stress and apoptosis. Moreover, protein levels of calcineurin A, ERK1/2, AKT, TGF-β, GRP78, cATF6, and CHOP were significantly reduced whereas SERCA2 level was upregulated in the VD3-treated hearts compared with control. These results suggest that VD3 attenuates cardiac remodeling and dysfunction induced by pressure overload, and this protective effect is associated with inhibition of multiple signaling pathways. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Transient upregulation of protein kinase C in pressure-overloaded neonatal rat myocardium

    Czech Academy of Sciences Publication Activity Database

    Hamplová, B.; Novák, F.; Kolář, František; Nováková, O.

    2010-01-01

    Roč. 59, č. 1 (2010), s. 25-33 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) 1M0510 Institutional research plan: CEZ:AV0Z50110509 Keywords : protein kinase C * cardiac development * pressure overload Subject RIV: ED - Physiology Impact factor: 1.646, year: 2010

  11. LRRC10 is required to maintain cardiac function in response to pressure overload.

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    Brody, Matthew J; Feng, Li; Grimes, Adrian C; Hacker, Timothy A; Olson, Timothy M; Kamp, Timothy J; Balijepalli, Ravi C; Lee, Youngsook

    2016-01-15

    We previously reported that the cardiomyocyte-specific leucine-rich repeat containing protein (LRRC)10 has critical functions in the mammalian heart. In the present study, we tested the role of LRRC10 in the response of the heart to biomechanical stress by performing transverse aortic constriction on Lrrc10-null (Lrrc10(-/-)) mice. Mild pressure overload induced severe cardiac dysfunction and ventricular dilation in Lrrc10(-/-) mice compared with control mice. In addition to dilation and cardiomyopathy, Lrrc10(-/-) mice showed a pronounced increase in heart weight with pressure overload stimulation and a more dramatic loss of cardiac ventricular performance, collectively suggesting that the absence of LRRC10 renders the heart more disease prone with greater hypertrophy and structural remodeling, although rates of cardiac fibrosis and myocyte dropout were not different from control mice. Lrrc10(-/-) cardiomyocytes also exhibited reduced contractility in response to β-adrenergic stimulation, consistent with loss of cardiac ventricular performance after pressure overload. We have previously shown that LRRC10 interacts with actin in the heart. Here, we show that His(150) of LRRC10 was required for an interaction with actin, and this interaction was reduced after pressure overload, suggesting an integral role for LRRC10 in the response of the heart to mechanical stress. Importantly, these experiments demonstrated that LRRC10 is required to maintain cardiac performance in response to pressure overload and suggest that dysregulated expression or mutation of LRRC10 may greatly sensitize human patients to more severe cardiac disease in conditions such as chronic hypertension or aortic stenosis. Copyright © 2016 the American Physiological Society.

  12. Changes in right ventricular function assessed by echocardiography in dog models of mild RV pressure overload.

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    Morita, Tomoya; Nakamura, Kensuke; Osuga, Tatsuyuki; Yokoyama, Nozomu; Morishita, Keitaro; Sasaki, Noboru; Ohta, Hiroshi; Takiguchi, Mitsuyoshi

    2017-07-01

    The assessment of hemodynamic change by echocardiography is clinically useful in patients with pulmonary hypertension. Recently, mild elevation of the mean pulmonary arterial pressure (PAP) has been shown to be associated with increased mortality. However, changes in the echocardiographic indices of right ventricular (RV) function are still unknown. The objective of this study was to validate the relationship between echocardiographic indices of RV function and right heart catheterization variables under a mild RV pressure overload condition. Echocardiography and right heart catheterization were performed in dog models of mild RV pressure overload induced by thromboxane A 2 analog (U46619) (n=7). The mean PAP was mildly increased (19.3±1.1 mm Hg), and the cardiac index was decreased. Most echocardiographic indices of RV function were significantly impaired even under a mild RV pressure overload condition. Multivariate analysis revealed that the RV free wall longitudinal strain (RVLS), standard deviation of the time-to-peak longitudinal strain of RV six segments (RV-SD) by speckle-tracking echocardiography, and Tei index were independent echocardiographic predictors of the mean PAP (free wall RVLS, β=-0.60, P<.001; RV-SD, β=0.40, P=.011), pulmonary vascular resistance (free wall RVLS, β=-0.39, P=.020; RV-SD, β=0.47, P=.0086; Tei index, β=0.34, P=.047), and cardiac index (Tei index, β=-0.65, P<.001). Free wall RVLS, RV-SD, and Tei index are useful for assessing the hemodynamic change under a mild RV pressure overload condition. © 2017, Wiley Periodicals, Inc.

  13. Fatty acid utilization in pressure-overload hypertrophied rat hearts

    International Nuclear Information System (INIS)

    Reibel, D.K.; O'Rourke, B.

    1986-01-01

    The authors have previously shown that the levels of total tissue coenzyme A and carnitine are reduced in hypertrophied hearts of rats subjected to aortic constriction. It was therefore of interest to determine if these changes were associated with alterations in fatty acid oxidation by the hypertrophied myocardium. Hearts were excised from sham-operated and aortic-constricted rats and perfused at 10 cm H 2 O left atrial filling pressure with a ventricular afterload of 80 cm of H 2 O with buffer containing 1.2 mM 14 C-linoleate. Heart rate and peak systolic pressure were not different in control and hypertrophied hearts. 14 CO 2 production was linear in both groups of hearts between 10 and 30 minutes of perfusion. The rate of fatty acid oxidation determined by 14 CO 2 production during this time was 0.728 +/- 0.06 μmoles/min/g dry in control hearts and 0.710 +/- 0.02 μmoles/min/g dry in hypertrophied hearts. Comparable rates of fatty acid oxidation were associated with comparable rates of O 2 consumption in the two groups of hearts (39.06 +/- 3.50 and 36.78 +/- 2.39 μmoles/g dry/min for control and hypertrophied hearts, respectively). The data indicate that the ability of the hypertrophied heart to oxidize fatty acids under these perfusion conditions is not impaired in spite of significant reductions in tissue levels of coenzyme A and carnitine

  14. Loss of Akap1 Exacerbates Pressure Overload-Induced Cardiac Hypertrophy and Heart Failure

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    Gabriele G. Schiattarella

    2018-05-01

    Full Text Available Left ventricular hypertrophy (LVH is a major contributor to the development of heart failure (HF. Alterations in cyclic adenosine monophosphate (cAMP-dependent signaling pathways participate in cardiomyocyte hypertrophy and mitochondrial dysfunction occurring in LVH and HF. cAMP signals are received and integrated by a family of cAMP-dependent protein kinase A (PKA anchor proteins (AKAPs, tethering PKA to discrete cellular locations. AKAPs encoded by the Akap1 gene (mitoAKAPs promote PKA mitochondrial targeting, regulating mitochondrial structure and function, reactive oxygen species production, and cell survival. To determine the role of mitoAKAPs in LVH development, in the present investigation, mice with global genetic deletion of Akap1 (Akap1-/-, Akap1 heterozygous (Akap1+/-, and their wild-type (wt littermates underwent transverse aortic constriction (TAC or SHAM procedure for 1 week. In wt mice, pressure overload induced the downregulation of AKAP121, the major cardiac mitoAKAP. Compared to wt, Akap1-/- mice did not display basal alterations in cardiac structure or function and cardiomyocyte size or fibrosis. However, loss of Akap1 exacerbated LVH and cardiomyocyte hypertrophy induced by pressure overload and accelerated the progression toward HF in TAC mice, and these changes were not observed upon prevention of AKAP121 degradation in seven in absentia homolog 2 (Siah2 knockout mice (Siah2-/-. Loss of Akap1 was also associated to a significant increase in cardiac apoptosis as well as lack of activation of Akt signaling after pressure overload. Taken together, these results demonstrate that in vivo genetic deletion of Akap1 enhances LVH development and accelerates pressure overload-induced cardiac dysfunction, pointing at Akap1 as a novel repressor of pathological LVH. These results confirm and extend the important role of mitoAKAPs in cardiac response to stress.

  15. Attenuated hypertrophic response to pressure overload in a lamin A/C haploinsufficiency mouse.

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    Cupesi, Mihaela; Yoshioka, Jun; Gannon, Joseph; Kudinova, Anastacia; Stewart, Colin L; Lammerding, Jan

    2010-06-01

    Inherited mutations cause approximately 30% of all dilated cardiomyopathy cases, with autosomal dominant mutations in the LMNA gene accounting for more than one third of these. The LMNA gene encodes the nuclear envelope proteins lamins A and C, which provide structural support to the nucleus and also play critical roles in transcriptional regulation. Functional deletion of a single allele is sufficient to trigger dilated cardiomyopathy in humans and mice. However, whereas Lmna(-/-) mice develop severe muscular dystrophy and dilated cardiomyopathy and die by 8 weeks of age, heterozygous Lmna(+/-) mice have a much milder phenotype, with changes in ventricular function and morphology only becoming apparent at 1 year of age. Here, we studied 8- to 20-week-old Lmna(+/-) mice and wild-type littermates in a pressure overload model to examine whether increased mechanical load can accelerate or exacerbate myocardial dysfunction in the heterozygotes. While overall survival was similar between genotypes, Lmna(+/-) animals had a significantly attenuated hypertrophic response to pressure overload as evidenced by reduced ventricular mass and myocyte size. Analysis of pressure overload-induced transcriptional changes suggested that the reduced hypertrophy in the Lmna(+/-) mice was accompanied by impaired activation of the mechanosensitive gene Egr-1. In conclusion, our findings provide further support for a critical role of lamins A and C in regulating the cellular response to mechanical stress in cardiomyocytes and demonstrate that haploinsufficiency of lamins A and C alone is sufficient to alter hypertrophic responses and cardiac function in the face of pressure overload in the heart. (c) 2009 Elsevier Ltd. All rights reserved.

  16. Loss of Akap1 Exacerbates Pressure Overload-Induced Cardiac Hypertrophy and Heart Failure.

    Science.gov (United States)

    Schiattarella, Gabriele G; Boccella, Nicola; Paolillo, Roberta; Cattaneo, Fabio; Trimarco, Valentina; Franzone, Anna; D'Apice, Stefania; Giugliano, Giuseppe; Rinaldi, Laura; Borzacchiello, Domenica; Gentile, Alessandra; Lombardi, Assunta; Feliciello, Antonio; Esposito, Giovanni; Perrino, Cinzia

    2018-01-01

    Left ventricular hypertrophy (LVH) is a major contributor to the development of heart failure (HF). Alterations in cyclic adenosine monophosphate (cAMP)-dependent signaling pathways participate in cardiomyocyte hypertrophy and mitochondrial dysfunction occurring in LVH and HF. cAMP signals are received and integrated by a family of cAMP-dependent protein kinase A (PKA) anchor proteins (AKAPs), tethering PKA to discrete cellular locations. AKAPs encoded by the Akap1 gene (mitoAKAPs) promote PKA mitochondrial targeting, regulating mitochondrial structure and function, reactive oxygen species production, and cell survival. To determine the role of mitoAKAPs in LVH development, in the present investigation, mice with global genetic deletion of Akap1 ( Akap1 -/- ), Akap1 heterozygous ( Akap1 +/- ), and their wild-type ( wt ) littermates underwent transverse aortic constriction (TAC) or SHAM procedure for 1 week. In wt mice, pressure overload induced the downregulation of AKAP121, the major cardiac mitoAKAP. Compared to wt, Akap1 -/- mice did not display basal alterations in cardiac structure or function and cardiomyocyte size or fibrosis. However, loss of Akap1 exacerbated LVH and cardiomyocyte hypertrophy induced by pressure overload and accelerated the progression toward HF in TAC mice, and these changes were not observed upon prevention of AKAP121 degradation in seven in absentia homolog 2 ( Siah2 ) knockout mice ( Siah2 -/- ). Loss of Akap1 was also associated to a significant increase in cardiac apoptosis as well as lack of activation of Akt signaling after pressure overload. Taken together, these results demonstrate that in vivo genetic deletion of Akap1 enhances LVH development and accelerates pressure overload-induced cardiac dysfunction, pointing at Akap1 as a novel repressor of pathological LVH. These results confirm and extend the important role of mitoAKAPs in cardiac response to stress.

  17. Signaling pathway-focused gene expression profiling in pressure overloaded hearts

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    Marco Musumeci

    2011-01-01

    Full Text Available The β-blocker propranolol displays antihypertrophic and antifibrotic properties in the heart subjected to pressure overload. Yet the underlying mechanisms responsible for these important effects remain to be completely understood. The purpose of this study was to determine signaling pathway-focused gene expression profile associated with the antihypertrophic action of propranolol in pressure overloaded hearts. To address this question, a focused real-time PCR array was used to screen left ventricular RNA expression of 84 gene transcripts representative of 18 different signaling pathways in C57BL/6 mice subjected to transverse aortic constriction (TAC or sham surgery. On the surgery day, mice received either propranolol (80 mg/kg/day or vehicle for 14 days. TAC caused a 49% increase in the left ventricular weight-to-body weight (LVW/BW ratio without changing gene expression. Propranolol blunted LVW/BW ratio increase by approximately 50% while causing about a 3-fold increase in the expression of two genes, namely Brca1 and Cdkn2a, belonging to the TGF-beta and estrogen pathways, respectively. In conclusion, after 2 weeks of pressure overload, TAC hearts show a gene expression profile superimposable to that of sham hearts. Conversely, propranolol treatment is associated with an increased expression of genes which negatively regulate cell cycle progression. It remains to be established whether a mechanistic link between gene expression changes and the antihypertrophic action of propranolol occurs.

  18. Cardiac-specific overexpression of aldehyde dehydrogenase 2 exacerbates cardiac remodeling in response to pressure overload

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    Sujith Dassanayaka

    2018-07-01

    Full Text Available Pathological cardiac remodeling during heart failure is associated with higher levels of lipid peroxidation products and lower abundance of several aldehyde detoxification enzymes, including aldehyde dehydrogenase 2 (ALDH2. An emerging idea that could explain these findings concerns the role of electrophilic species in redox signaling, which may be important for adaptive responses to stress or injury. The purpose of this study was to determine whether genetically increasing ALDH2 activity affects pressure overload-induced cardiac dysfunction. Mice subjected to transverse aortic constriction (TAC for 12 weeks developed myocardial hypertrophy and cardiac dysfunction, which were associated with diminished ALDH2 expression and activity. Cardiac-specific expression of the human ALDH2 gene in mice augmented myocardial ALDH2 activity but did not improve cardiac function in response to pressure overload. After 12 weeks of TAC, ALDH2 transgenic mice had larger hearts than their wild-type littermates and lower capillary density. These findings show that overexpression of ALDH2 augments the hypertrophic response to pressure overload and imply that downregulation of ALDH2 may be an adaptive response to certain forms of cardiac pathology. Keywords: Heart failure, Hypertrophy, Oxidative stress, Aldehydes, Cardiac remodeling, Hormesis

  19. Short-Term Caloric Restriction Suppresses Cardiac Oxidative Stress and Hypertrophy Caused by Chronic Pressure Overload.

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    Kobara, Miyuki; Furumori-Yukiya, Akiko; Kitamura, Miho; Matsumura, Mihoko; Ohigashi, Makoto; Toba, Hiroe; Nakata, Tetsuo

    2015-08-01

    Caloric restriction (CR) prevents senescent changes, in which reactive oxygen species (ROS) have a critical role. Left ventricular (LV) hypertrophy is a risk factor for cardiovascular diseases. We examined whether CR alters cardiac redox state and hypertrophy from chronic pressure overload. Male c57BL6 mice were subjected to ascending aortic constriction (AAC) with ad libitum caloric intake (AL + AAC group) or 40% restricted caloric intake (CR + AAC group). CR was initiated 2 weeks before AAC and was continued for 4 weeks. Two weeks after constriction, AAC increased LV wall thickness, impaired transmitral flow velocity, and augmented myocyte hypertrophy and fibrosis, in association with enhancement of BNP and collagen III expressions in the AL + AAC group. In the AL + AAC group, oxidative stress in cardiac tissue and mitochondria were enhanced, and NADPH oxidase activity and mitochondrial ROS production were elevated. These changes were significantly attenuated in the CR + AAC group. Additionally, in antioxidant systems, myocardial glutathione peroxidase and superoxide dismutase activities were enhanced in the CR + AAC group. Chronic pressure overload increased cardiac oxidative damage, in association with cardiac hypertrophy and fibrosis. Short-term CR suppressed oxidative stress and improved cardiac function, suggesting that short-term CR could be a useful strategy to prevent pressure overload-induced cardiac injury. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Pivotal role of cardiomyocyte TGF-β signaling in the murine pathological response to sustained pressure overload

    NARCIS (Netherlands)

    Koitabashi, Norimichi; Danner, Thomas; Zaiman, Ari L.; Pinto, Yigal M.; Rowell, Janelle; Mankowski, Joseph; Zhang, Dou; Nakamura, Taishi; Takimoto, Eiki; Kass, David A.

    2011-01-01

    The cardiac pathological response to sustained pressure overload involves myocyte hypertrophy and dysfunction along with interstitial changes such as fibrosis and reduced capillary density. These changes are orchestrated by mechanical forces and factors secreted between cells. One such secreted

  1. Maximal respiratory pressures and pulmonary function in male runners.

    OpenAIRE

    Cordain, L; Glisan, B J; Latin, R W; Tucker, A; Stager, J M

    1987-01-01

    To determine the effects of long term exercise on respiratory muscle strength, maximal inspiratory (Pl max) and expiratory (PE max) pressures, pulmonary volumes and capacities and anthropometric parameters were measured in a group of 101 male runners aged 16 to 58 years. The runners exhibited significantly (p less than 0.05) lower PE max (202 +/- 41 cm H2O and significantly greater residual lung volumes (RV) (2.08 +/- 0.49 L) than predicted values for normal subjects of similar height and age...

  2. Extracellular high-mobility group box 1 mediates pressure overload-induced cardiac hypertrophy and heart failure.

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    Zhang, Lei; Liu, Ming; Jiang, Hong; Yu, Ying; Yu, Peng; Tong, Rui; Wu, Jian; Zhang, Shuning; Yao, Kang; Zou, Yunzeng; Ge, Junbo

    2016-03-01

    Inflammation plays a key role in pressure overload-induced cardiac hypertrophy and heart failure, but the mechanisms have not been fully elucidated. High-mobility group box 1 (HMGB1), which is increased in myocardium under pressure overload, may be involved in pressure overload-induced cardiac injury. The objectives of this study are to determine the role of HMGB1 in cardiac hypertrophy and cardiac dysfunction under pressure overload. Pressure overload was imposed on the heart of male wild-type mice by transverse aortic constriction (TAC), while recombinant HMGB1, HMGB1 box A (a competitive antagonist of HMGB1) or PBS was injected into the LV wall. Moreover, cardiac myocytes were cultured and given sustained mechanical stress. Transthoracic echocardiography was performed after the operation and sections for histological analyses were generated from paraffin-embedded hearts. Relevant proteins and genes were detected. Cardiac HMGB1 expression was increased after TAC, which was accompanied by its translocation from nucleus to both cytoplasm and intercellular space. Exogenous HMGB1 aggravated TAC-induced cardiac hypertrophy and cardiac dysfunction, as demonstrated by echocardiographic analyses, histological analyses and foetal cardiac genes detection. Nevertheless, the aforementioned pathological change induced by TAC could partially be reversed by HMGB1 inhibition. Consistent with the in vivo observations, mechanical stress evoked the release and synthesis of HMGB1 in cultured cardiac myocytes. This study indicates that the activated and up-regulated HMGB1 in myocardium, which might partially be derived from cardiac myocytes under pressure overload, may be of crucial importance in pressure overload-induced cardiac hypertrophy and cardiac dysfunction. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  3. Crucial role of rho-kinase in pressure overload-induced right ventricular hypertrophy and dysfunction in mice.

    Science.gov (United States)

    Ikeda, Shohei; Satoh, Kimio; Kikuchi, Nobuhiro; Miyata, Satoshi; Suzuki, Kota; Omura, Junichi; Shimizu, Toru; Kobayashi, Kenta; Kobayashi, Kazuto; Fukumoto, Yoshihiro; Sakata, Yasuhiko; Shimokawa, Hiroaki

    2014-06-01

    Right ventricular (RV) failure is the leading cause of death in various cardiopulmonary diseases, including pulmonary hypertension. It is generally considered that the RV is vulnerable to pressure overload as compared with the left ventricle (LV). However, as compared with LV failure, the molecular mechanisms of RV failure are poorly understood, and hence therapeutic targets of the disorder remain to be elucidated. Thus, we aimed to identify molecular therapeutic targets for RV failure in a mouse model of pressure overload. To induce pressure overload to respective ventricles, we performed pulmonary artery constriction or transverse aortic constriction in mice. We first performed microarray analysis and found that the molecules related to RhoA/Rho-kinase and integrin pathways were significantly upregulated in the RV with pulmonary artery constriction compared with the LV with transverse aortic constriction. Then, we examined the responses of both ventricles to chronic pressure overload in vivo. We demonstrated that compared with transverse aortic constriction, pulmonary artery constriction caused greater extents of mortality, Rho-kinase expression (especially ROCK2 isoform), and oxidative stress in pressure-overloaded RV, reflecting the weakness of the RV in response to pressure overload. Furthermore, mice with myocardial-specific overexpression of dominant-negative Rho-kinase showed resistance to pressure overload-induced hypertrophy and dysfunction associated with reduced oxidative stress. Finally, dominant-negative Rho-kinase mice showed a significantly improved long-term survival in both pulmonary artery constriction and transverse aortic constriction as compared with littermate controls. These results indicate that the Rho-kinase pathway plays a crucial role in RV hypertrophy and dysfunction, suggesting that the pathway is a novel therapeutic target of RV failure in humans. © 2014 American Heart Association, Inc.

  4. Deletion of Interleukin-6 Attenuates Pressure Overload-Induced Left Ventricular Hypertrophy and Dysfunction

    Science.gov (United States)

    Afzal, Muhammad R.; Samanta, Anweshan; Xuan, Yu-Ting; Girgis, Magdy; Elias, Harold K; Zhu, Yanqing; Davani, Arash; Yang, Yanjuan; Chen, Xing; Ye, Sheng; Wang, Ou-Li; Chen, Lei; Hauptman, Jeryl; Vincent, Robert J.; Dawn, Buddhadeb

    2016-01-01

    Rationale The role of interleukin (IL)-6 in the pathogenesis of cardiac myocyte hypertrophy remains controversial. Objective To conclusively determine whether IL-6 signaling is essential for the development of pressure overload-induced left ventricular (LV) hypertrophy, and to elucidate the underlying molecular pathways. Methods and Results Wild-type (WT) and IL-6 knockout (IL-6−/−) mice underwent sham surgery or transverse aortic constriction (TAC) to induce pressure overload. Serial echocardiograms and terminal hemodynamic studies revealed attenuated LV hypertrophy and superior preservation of LV function in IL-6−/− mice after TAC. The extents of LV remodeling, fibrosis, and apoptosis were reduced in IL-6−/− hearts after TAC. Transcriptional and protein assays of myocardial tissue identified CaMKII and STAT3 activation as important underlying mechanisms during cardiac hypertrophy induced by TAC. The involvement of these pathways in myocyte hypertrophy was verified in isolated cardiac myocytes from WT and IL-6−/− mice exposed to pro-hypertrophy agents. Furthermore, overexpression of CaMKII in H9c2 cells increased STAT3 phosphorylation, and exposure of H9c2 cells to IL-6 resulted in STAT3 activation that was attenuated by CaMKII inhibition. Together these results identify the importance of CaMKII-dependent activation of STAT3 during cardiac myocyte hypertrophy via IL-6 signaling. Conclusions Genetic deletion of IL-6 attenuates TAC-induced LV hypertrophy and dysfunction, indicating a critical role played by IL-6 in the pathogenesis of LV hypertrophy in response to pressure overload. CaMKII plays an important role in IL-6-induced STAT3 activation and consequent cardiac myocyte hypertrophy. These findings may have significant therapeutic implications for LV hypertrophy and failure in patients with hypertension. PMID:27126808

  5. Pressure Overload by Transverse Aortic Constriction Induces Maladaptive Hypertrophy in a Titin-Truncated Mouse Model

    Directory of Open Access Journals (Sweden)

    Qifeng Zhou

    2015-01-01

    Full Text Available Mutations in the giant sarcomeric protein titin (TTN are a major cause for inherited forms of dilated cardiomyopathy (DCM. We have previously developed a mouse model that imitates a TTN truncation mutation we found in a large pedigree with DCM. While heterozygous Ttn knock-in mice do not display signs of heart failure under sedentary conditions, they recapitulate the human phenotype when exposed to the pharmacological stressor angiotensin II or isoproterenol. In this study we investigated the effects of pressure overload by transverse aortic constriction (TAC in heterozygous (Het Ttn knock-in mice. Two weeks after TAC, Het mice developed marked impairment of left ventricular ejection fraction (p<0.05, while wild-type (WT TAC mice did not. Het mice also trended toward increased ventricular end diastolic pressure and volume compared to WT littermates. We found an increase in histologically diffuse cardiac fibrosis in Het compared to WT in TAC mice. This study shows that a pattern of DCM can be induced by TAC-mediated pressure overload in a TTN-truncated mouse model. This model enlarges our arsenal of cardiac disease models, adding a valuable tool to understand cardiac pathophysiological remodeling processes and to develop therapeutic approaches to combat heart failure.

  6. Comparison of three protocols for measuring the maximal respiratory pressures

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    Isabela Maria B. Sclauser Pessoa

    Full Text Available Introduction To avoid the selection of submaximal efforts during the assessment of maximal inspiratory and expiratory pressures (MIP and MEP, some reproducibility criteria have been suggested. Criteria that stand out are those proposed by the American Thoracic Society (ATS and European Respiratory Society (ERS and by the Brazilian Thoracic Association (BTA. However, no studies were found that compared these criteria or assessed the combination of both protocols. Objectives To assess the pressure values selected and the number of maneuvers required to achieve maximum performance using the reproducibility criteria proposed by the ATS/ERS, the BTA and the present study. Materials and method 113 healthy subjects (43.04 ± 16.94 years from both genders were assessed according to the criteria proposed by the ATS/ERS, BTA and the present study. Descriptive statistics were used for analysis, followed by ANOVA for repeated measures and post hoc LSD or by Friedman test and post hoc Wilcoxon, according to the data distribution. Results The criterion proposed by the present study resulted in a significantly higher number of maneuvers (MIP and MEP – median and 25%-75% interquartile range: 5[5-6], 4[3-5] and 3[3-4] for the present study criterion, BTA and ATS/ERS, respectively; p < 0.01 and higher pressure values (MIP – mean and 95% confidence interval: 103[91.43-103.72], 100[97.19-108.83] and 97.6[94.06-105.95]; MEP: median and 25%-75% interquartile range: 124.2[101.4-165.9], 123.3[95.4-153.8] and 118.4[95.5-152.7]; p < 0.05. Conclusion The proposed criterion resulted in the selection of pressure values closer to the individual’s maximal capacity. This new criterion should be considered in future studies concerning MIP and MEP measurements.

  7. Brief pressure overload of the left ventricle reduces myocardial infarct size via activation of protein kinase C.

    Science.gov (United States)

    Tang, Chia-Yu; Lai, Chang-Chi; Chiang, Shu-Chiung; Tseng, Kuo-Wei; Huang, Cheng-Hsiung

    2015-09-01

    We have previously reported that brief pressure overload of the left ventricle reduced myocardial infarct (MI) size. However, the role of protein kinase C (PKC) remains uncertain. In this study, we investigated whether pressure overload reduces MI size by activating PKC. MI was induced by a 40-minute occlusion of the left anterior descending coronary artery and a 3-hour reperfusion in anesthetized Sprague-Dawley rats. MI size was determined using triphenyl tetrazolium chloride staining. Brief pressure overload was achieved by two 10-minute partial snarings of the ascending aorta, raising the systolic left ventricular pressure 50% above the baseline value. Ischemic preconditioning was elicited by two 10-minute coronary artery occlusions and 10-minute reperfusions. Dimethyl sulfoxide (vehicle) or calphostin C (0.1 mg/kg, a specific inhibitor of PKC) was administered intravenously as pretreatment. The MI size, expressed as the percentage of the area at risk, was significantly reduced in the pressure overload group and the ischemic preconditioning group (19.0 ± 2.9% and 18.7 ± 3.0% vs. 26.1 ± 2.6% in the control group, where p overload and ischemic preconditioning (25.2 ± 2.4% and 25.0 ± 2.3%, where p overload of the left ventricle reduced MI size. Since calphostin C significantly limited the decrease of MI size, our results suggested that brief pressure overload reduces MI size via activation of PKC. Copyright © 2015. Published by Elsevier Taiwan.

  8. Leukocytic Toll-Like Receptor 2 Deficiency Preserves Cardiac Function And Reduces Fibrosis In Sustained Pressure Overload

    NARCIS (Netherlands)

    Wang, Jiong-Wei; Fontes, Magda S. C.; Wang, Xiaoyuan; Chong, Suet Yen; Kessler, Elise L.; Zhang, Ya-Nan; de Haan, Judith J.; Arslan, Fatih; de Jager, Saskia C. A.; Timmers, Leo; van Veen, Toon A. B.; Lam, Carolyn S. P.; de Kleijn, Dominique P. V.

    2017-01-01

    An involement of Toll-like receptor 2 (TLR2) has been established in cardiac dysfunction after acute myocardial infarction; however, its role in chronic pressure overload is unclear. We sought to evaluate the role of TLR2 in cardiac hypertrophy, fibrosis and dysfunction in sustained pressure

  9. Pressure overload-induced mild cardiac hypertrophy reduces leftventricular transmural differences in mitochondrial respiratory chainactivity and increases oxidative stress

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    Michel eKINDO

    2012-08-01

    Full Text Available Objective: Increased mechanical stress and contractility characterizes normal left ventricular subendocardium (Endo but whether Endo mitochondrial respiratory chain complex activities is reduced as compared to subepicardium (Epi and whether pressure overload-induced left ventricular hypertrophy (LVH might modulate transmural gradients through increased reactive oxygen species (ROS production is unknown. Methods: LVH was induced by 6 weeks abdominal aortic banding and cardiac structure and function were determined with echocardiography and catheterization in sham-operated and LVH rats (n=10 for each group. Mitochondrial respiration rates, coupling, content and ROS production were measured in LV Endo and Epi, using saponin-permeabilised fibres, Amplex Red fluorescence and citrate synthase activity.Results: In sham, a transmural respiratory gradient was observed with decreases in endo maximal oxidative capacity (-36.7%, P<0.01 and complex IV activity (-57.4%, P<0.05. Mitochondrial hydrogen peroxide (H2O2 production was similar in both LV layers.Aortic banding induced mild LVH (+31.7% LV mass, associated with normal LV fractional shortening and end diastolic pressure. LVH reduced maximal oxidative capacity (-23.6 and -33.3%, increased mitochondrial H2O2 production (+86.9 and +73.1%, free radical leak (+27.2% and +36.3% and citrate synthase activity (+27.2% and +36.3% in Endo and Epi, respectively.Transmural mitochondrial respiratory chain complex IV activity was reduced in LVH (-57.4 vs –12.2%; P=0.02. Conclusions: Endo mitochondrial respiratory chain complexes activities are reduced compared to LV Epi. Mild LVH impairs mitochondrial oxidative capacity, increases oxidative stress and reduces transmural complex IV activity. Further studies will be helpful to determine whether reduced LV transmural gradient in mitochondrial respiration might be a new marker of a transition from uncomplicated toward complicated LVH.

  10. Increased natriuretic peptide receptor A and C gene expression in rats with pressure-overload cardiac hypertrophy

    DEFF Research Database (Denmark)

    Christoffersen, Tue E.H.; Aplin, Mark; Strom, Claes C.

    2006-01-01

    also affects cardiac hypertrophy and fibrosis. In this study we examined the expression of genes for the NPRs in rats with pressure-overload cardiac hypertrophy. The ANG II type 1 receptor was blocked with losartan (10 mg.kg(-1).day(-1)) to investigate a possible role of the renin-angiotensin system......RNAs for the natriuretic peptides or their receptors. Although increased gene expression does not necessarily convey a higher concentration of the protein, the data suggest that pressure overload is accompanied by upregulation of not only ANP and BNP but also their receptors NPR-A and NPR-C in the left ventricle....

  11. Taxifolin protects against cardiac hypertrophy and fibrosis during biomechanical stress of pressure overload

    International Nuclear Information System (INIS)

    Guo, Haipeng; Zhang, Xin; Cui, Yuqian; Zhou, Heng; Xu, Dachun; Shan, Tichao; Zhang, Fan; Guo, Yuan; Chen, Yuguo; Wu, Dawei

    2015-01-01

    Cardiac hypertrophy is a key pathophysiological component to biomechanical stress, which has been considered to be an independent and predictive risk factor for adverse cardiovascular events. Taxifolin (TAX) is a typical plant flavonoid, which has long been used clinically for treatment of cardiovascular and cerebrovascular diseases. However, very little is known about whether TAX can influence the development of cardiac hypertrophy. In vitro studies, we found that TAX concentration-dependently inhibited angiotensin II (Ang II) induced hypertrophy and protein synthesis in cardiac myocytes. Then we established a mouse model by transverse aortic constriction (TAC) to further confirm our findings. It was demonstrated that TAX prevented pressure overload induced cardiac hypertrophy in mice, as assessed by ventricular mass/body weight, echocardiographic parameters, myocyte cross-sectional area, and the expression of ANP, BNP and β-MHC. The excess production of reactive oxygen species (ROS) played critical role in the development of cardiac hypertrophy. TAX arrested oxidative stress and decreased the expression of 4-HNE induced by pressure overload. Moreover, TAX negatively modulated TAC-induced phosphorylation of ERK1/2 and JNK1/2. Further studies showed that TAX significantly attenuated left ventricular fibrosis and collagen synthesis through abrogating the phosphorylation of Smad2 and Smad2/3 nuclear translocation. These results demonstrated that TAX could inhibit cardiac hypertrophy and attenuate ventricular fibrosis after pressure overload. These beneficial effects were at least through the inhibition of the excess production of ROS, ERK1/2, JNK1/2 and Smad signaling pathways. Therefore, TAX might be a potential candidate for the treatment of cardiac hypertrophy and fibrosis. - Highlights: • We focus on the protective effect of taxifolin on cardiac remodeling. • Taxifolin inhibited cardiac hypertrophy and attenuated ventricular fibrosis. • Taxifolin

  12. Taxifolin protects against cardiac hypertrophy and fibrosis during biomechanical stress of pressure overload

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Haipeng; Zhang, Xin [Department of Critical Care Medicine, Qilu Hospital of Shandong University, Jinan (China); Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Qilu Hospital of Shandong University, Jinan (China); Cui, Yuqian [Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Qilu Hospital of Shandong University, Jinan (China); Zhou, Heng [Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan (China); Xu, Dachun [Department of Cardiology, Shanghai Tenth People' s Hospital of Tongji University, Shanghai (China); Shan, Tichao; Zhang, Fan [Department of Critical Care Medicine, Qilu Hospital of Shandong University, Jinan (China); Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Qilu Hospital of Shandong University, Jinan (China); Guo, Yuan [Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Qilu Hospital of Shandong University, Jinan (China); Chen, Yuguo, E-mail: chen919085@163.com [Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Qilu Hospital of Shandong University, Jinan (China); Department of Emergency, Qilu Hospital of Shandong University, Jinan (China); Wu, Dawei, E-mail: wdwu55@163.com [Department of Critical Care Medicine, Qilu Hospital of Shandong University, Jinan (China); Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Qilu Hospital of Shandong University, Jinan (China)

    2015-09-01

    Cardiac hypertrophy is a key pathophysiological component to biomechanical stress, which has been considered to be an independent and predictive risk factor for adverse cardiovascular events. Taxifolin (TAX) is a typical plant flavonoid, which has long been used clinically for treatment of cardiovascular and cerebrovascular diseases. However, very little is known about whether TAX can influence the development of cardiac hypertrophy. In vitro studies, we found that TAX concentration-dependently inhibited angiotensin II (Ang II) induced hypertrophy and protein synthesis in cardiac myocytes. Then we established a mouse model by transverse aortic constriction (TAC) to further confirm our findings. It was demonstrated that TAX prevented pressure overload induced cardiac hypertrophy in mice, as assessed by ventricular mass/body weight, echocardiographic parameters, myocyte cross-sectional area, and the expression of ANP, BNP and β-MHC. The excess production of reactive oxygen species (ROS) played critical role in the development of cardiac hypertrophy. TAX arrested oxidative stress and decreased the expression of 4-HNE induced by pressure overload. Moreover, TAX negatively modulated TAC-induced phosphorylation of ERK1/2 and JNK1/2. Further studies showed that TAX significantly attenuated left ventricular fibrosis and collagen synthesis through abrogating the phosphorylation of Smad2 and Smad2/3 nuclear translocation. These results demonstrated that TAX could inhibit cardiac hypertrophy and attenuate ventricular fibrosis after pressure overload. These beneficial effects were at least through the inhibition of the excess production of ROS, ERK1/2, JNK1/2 and Smad signaling pathways. Therefore, TAX might be a potential candidate for the treatment of cardiac hypertrophy and fibrosis. - Highlights: • We focus on the protective effect of taxifolin on cardiac remodeling. • Taxifolin inhibited cardiac hypertrophy and attenuated ventricular fibrosis. • Taxifolin

  13. Low-intensity pulsed ultrasound enhances angiogenesis and ameliorates contractile dysfunction of pressure-overloaded heart in mice.

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Ogata

    Full Text Available Chronic left ventricular (LV pressure overload causes relative ischemia with resultant LV dysfunction. We have recently demonstrated that low-intensity pulsed ultrasound (LIPUS improves myocardial ischemia in a pig model of chronic myocardial ischemia through enhanced myocardial angiogenesis. In the present study, we thus examined whether LIPUS also ameliorates contractile dysfunction in LV pressure-overloaded hearts.Chronic LV pressure overload was induced with transverse aortic constriction (TAC in mice. LIPUS was applied to the whole heart three times in the first week after TAC and was repeated once a week for 7 weeks thereafter (n = 22. Animals in the control groups received the sham treatment without LIPUS (n = 23. At 8 weeks after TAC, LV fractional shortening was depressed in the TAC-Control group, which was significantly ameliorated in the TAC-LIPUS group (30.4±0.5 vs. 36.2±3.8%, P<0.05. Capillary density was higher and perivascular fibrosis was less in the LV in the TAC-LIPUS group than in the TAC-Control group. Myocardial relative ischemia evaluated with hypoxyprobe was noted in the TAC-Control group, which was significantly attenuated in the TAC-LIPUS group. In the TAC-LIPUS group, as compared with the control group, mRNA expressions of BNP and collagen III were significantly lower (both P<0.05 and protein expressions of VEGF and eNOS were significantly up-regulated associated with Akt activation (all P<0.05. No adverse effect related to the LIPUS therapy was noted.These results indicate that the LIPUS therapy ameliorates contractile dysfunction in chronically pressure-overloaded hearts through enhanced myocardial angiogenesis and attenuated perivascular fibrosis. Thus, the LIPUS therapy may be a promising, non-invasive treatment for cardiac dysfunction due to chronic pressure overload.

  14. Effects of volume-based overload plyometric training on maximal-intensity exercise adaptations in young basketball players.

    Science.gov (United States)

    Asadi, Abbas; Ramirez-Campillo, Rodrigo; Meylan, Cesar; Nakamura, Fabio Y; Cañas-Jamett, Rodrigo; Izquierdo, Mikel

    2017-12-01

    The aim of the present study was to compare maximal-intensity exercise adaptations in young basketball players (who were strong individuals at baseline) participating in regular basketball training versus regular plus a volume-based plyometric training program in the pre-season period. Young basketball players were recruited and assigned either to a plyometric with regular basketball training group (experimental group [EG]; N.=8), or a basketball training only group (control group [CG]; N.=8). The athletes in EG performed periodized (i.e., from 117 to 183 jumps per session) plyometric training for eight weeks. Before and after the intervention, players were assessed in vertical and broad jump, change of direction, maximal strength and a 60-meter sprint test. No significant improvements were found in the CG, while the EG improved vertical jump (effect size [ES] 2.8), broad jump (ES=2.4), agility T test (ES=2.2), Illinois agility test (ES=1.4), maximal strength (ES=1.8), and 60-m sprint (ES=1.6) (Ptraining in addition to regular basketball practice can lead to meaningful improvements in maximal-intensity exercise adaptations among young basketball players during the pre-season.

  15. Cardiomyocyte Overexpression of FABP4 Aggravates Pressure Overload-Induced Heart Hypertrophy.

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    Ji Zhang

    Full Text Available Fatty acid binding protein 4 (FABP4 is a member of the intracellular lipid-binding protein family, responsible for the transportation of fatty acids. It is considered to express mainly in adipose tissues, and be strongly associated with inflammation, obesity, diabetes and cardiovasculardiseases. Here we report that FABP4 is also expressed in cardiomyocytes and plays an important role in regulating heart function under pressure overload. We generated heart-specific transgenic FABP4 (FABP4-TG mice using α myosin-heavy chain (α-MHC promoter and human FABP4 sequence, resulting in over-expression of FABP4 in cardiomyocytes. The FABP4-TG mice displayed normal cardiac morphology and contractile function. When they were subjected to the transverse aorta constriction (TAC procedure, the FABP4-TG mice developed more cardiac hypertrophy correlated with significantly increased ERK phosphorylation, compared with wild type controls. FABP4 over-expression in cardiomyocytes activated phosphor-ERK signal and up-regulate the expression of cardiac hypertrophic marker genes. Conversely, FABP4 induced phosphor-ERK signal and hypertrophic gene expressions can be markedly inhibited by an ERK inhibitor PD098059 as well as the FABP4 inhibitor BMS309403. These results suggest that FABP4 over-expression in cardiomyocytes can aggravate the development of cardiac hypertrophy through the activation of ERK signal pathway.

  16. Bone marrow support of the heart in pressure overload is lost with aging.

    Science.gov (United States)

    Sopko, Nikolai A; Turturice, Benjamin A; Becker, Mitchell E; Brown, Chase R; Dong, Feng; Popović, Zoran B; Penn, Marc S

    2010-12-21

    Exogenous stem cell delivery is under investigation to prevent and treat cardiac dysfunction. It is less studied as to the extent endogenous bone marrow derived stem cells contribute to cardiac homeostais in response to stress and the affects of aging on this stress response. To determine the role of bone marrow (BM) derived stem cells on cardiac homeostasis in response to pressure overload (PO) and how this response is altered by aging. Young (8 weeks) and old (>40 weeks) C57/b6 mice underwent homo- and heterochronic BM transplantation prior to transverse aortic constriction (TAC). We found that older BM is associated with decreased cardiac function following TAC. This decreased function is associated with decrease in BM cell engraftment, increased myocyte apoptosis, decreased myocyte hypertrophy, increased myocardial fibrosis and decreased cardiac function. Additionally, there is a decrease in activation of resident cells within the heart in response to PO in old mice. Interestingly, these effects are not due to alterations in vascular density or inflammation in response to PO or differences in ex vivo stem cell migration between young and old mice. BM derived stem cells are activated in response to cardiac PO, and the recruitment of BM derived cells are involved in cardiac myocyte hypertrophy and maintenance of function in response to PO which is lost with aging.

  17. CCR2+ Monocyte-Derived Infiltrating Macrophages Are Required for Adverse Cardiac Remodeling During Pressure Overload

    Directory of Open Access Journals (Sweden)

    Bindiya Patel, PhD

    2018-04-01

    Full Text Available Summary: Although chronic inflammation is a central feature of heart failure (HF, the immune cell profiles differ with different underlying causes. This suggests that for immunomodulatory therapy in HF to be successful, it needs to be tailored to the specific etiology. Here, the authors demonstrate that monocyte-derived C-C chemokine receptor 2 (CCR2+ macrophages infiltrate the heart early during pressure overload in mice, and that blocking this response either pharmacologically or with antibody-mediated CCR2+ monocyte depletion alleviates late pathological left ventricular remodeling and dysfunction, T-cell expansion, and cardiac fibrosis. Hence, suppression of CCR2+ monocytes/macrophages may be an important immunomodulatory therapeutic target to ameliorate pressure-overload HF. Key Words: cardiac remodeling, heart failure, inflammation, macrophages, T cells

  18. The Influence of Domestic Overload on the Association between Job Strain and Ambulatory Blood Pressure among Female Nursing Workers

    Directory of Open Access Journals (Sweden)

    Luciana Fernandes Portela

    2013-11-01

    Full Text Available Evidence suggests that the workplace plays an important etiologic role in blood pressure (BP alterations. Associations in female samples are controversial, and the domestic environment is hypothesized to be an important factor in this relationship. This study assessed the association between job strain and BP within a sample of female nursing workers, considering the potential role of domestic overload. A cross-sectional study was conducted in a group of 175 daytime workers who wore an ambulatory BP monitor for 24 h during a working day. Mean systolic and diastolic BP were calculated. Job strain was evaluated using the Demand-Control Model. Domestic overload was based on the level of responsibility in relation to four household tasks and on the number of beneficiaries. After adjustments no significant association between high job strain and BP was detected. Stratified analyses revealed that women exposed to both domestic overload and high job strain had higher systolic BP at home. These results indicate a possible interaction between domestic overload and job strain on BP levels and revealed the importance of domestic work, which is rarely considered in studies of female workers.

  19. Triptolide attenuates pressure overload-induced myocardial remodeling in mice via the inhibition of NLRP3 inflammasome expression

    International Nuclear Information System (INIS)

    Li, Rujun; Lu, Kuiying; Wang, Yao; Chen, Mingxing; Zhang, Fengyu; Shen, Hui; Yao, Deshan; Gong, Kaizheng; Zhang, Zhengang

    2017-01-01

    Triptolide is the predominant active component of the Chinese herb Tripterygium wilfordii Hook F (TwHF) that has been widely used to treat several chronic inflammatory diseases due to its immunosuppressive, anti-inflammatory, and anti-proliferative properties. In the present study, we elucidated the cardioprotective effects of triptolide against cardiac dysfunction and myocardial remodeling in chronic pressure-overloaded hearts. Furthermore, the potential mechanisms of triptolide were investigated. For this purpose, C57/BL6 mice were anesthetized and subjected to transverse aortic constriction (TAC) or sham operation. Six weeks after the operation, all mice were randomly divided into 4 groups: sham-operated with vehicle group, TAC with vehicle group, and TAC with triptolide (20 or 100 μg/kg/day intraperitoneal injection) groups. Our data showed that the levels of NLRP3 inflammasome were significantly increased in the TAC group and were associated with increased inflammatory mediators and profibrotic factor production, resulting in myocardial fibrosis, cardiomyocyte hypertrophy, and impaired cardiac function. Triptolide treatment attenuated TAC-induced myocardial remodeling, improved cardiac diastolic and systolic function, inhibited the NLRP3 inflammasome and downstream inflammatory mediators (IL-1β, IL-18, MCP-1, VCAM-1), activated the profibrotic TGF-β1 pathway, and suppressed macrophage infiltration in a dose-dependent manner. Our study demonstrated that the protective effect of triptolide against pressure overload in the heart may act by inhibiting the NLRP3 inflammasome-induced inflammatory response and activating the profibrotic pathway. - Highlights: • Chronic pressure overload increases expression of NLRP3 inflammasome in the heart. • Triptolide attenuates chronic pressure overload-induced myocardial remodeling. • The mechanism appears to involve inhibition of NLRP3 inflammasome expression. • Triptolide is a therapeutic candidate for

  20. Role of atrial endothelial cells in the development of atrial fibrosis and fibrillation in response to pressure overload.

    Science.gov (United States)

    Kume, Osamu; Teshima, Yasushi; Abe, Ichitaro; Ikebe, Yuki; Oniki, Takahiro; Kondo, Hidekazu; Saito, Shotaro; Fukui, Akira; Yufu, Kunio; Miura, Masahiro; Shimada, Tatsuo; Takahashi, Naohiko

    Monocyte chemoattractant protein-1 (MCP-1)-mediated inflammatory mechanisms have been shown to play a crucial role in atrial fibrosis induced by pressure overload. In the present study, we investigated whether left atrial endothelial cells would quickly respond structurally and functionally to pressure overload to trigger atrial fibrosis and fibrillation. Six-week-old male Sprague-Dawley rats underwent suprarenal abdominal aortic constriction (AAC) or a sham operation. By day 3 after surgery, macrophages were observed to infiltrate into the endocardium. The expression of MCP-1 and E-selectin in atrial endothelium and the expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and ED1 in left atrial tissue were enhanced. Atrial endothelial cells were irregularly hypertrophied with the disarrangement of lines of cells by scanning electron microscopy. Various-sized gap formations appeared along the border in atrial endothelial cells, and several macrophages were located just in the endothelial gap. Along with the development of heterogeneous interstitial fibrosis, interatrial conduction time was prolonged and the inducibility of atrial fibrillation by programmed extrastimuli was increased in the AAC rats compared to the sham-operated rats. Atrial endothelium responds rapidly to pressure overload by expressing adhesion molecules and MCP-1, which induce macrophage infiltration into the atrial tissues. These processes could be an initial step in the development of atrial remodeling for atrial fibrillation. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Microtubule depolymerization normalizes in vivo myocardial contractile function in dogs with pressure-overload left ventricular hypertrophy

    Science.gov (United States)

    Koide, M.; Hamawaki, M.; Narishige, T.; Sato, H.; Nemoto, S.; DeFreyte, G.; Zile, M. R.; Cooper G, I. V.; Carabello, B. A.

    2000-01-01

    BACKGROUND: Because initially compensatory myocardial hypertrophy in response to pressure overloading may eventually decompensate to myocardial failure, mechanisms responsible for this transition have long been sought. One such mechanism established in vitro is densification of the cellular microtubule network, which imposes a viscous load that inhibits cardiocyte contraction. METHODS AND RESULTS: In the present study, we extended this in vitro finding to the in vivo level and tested the hypothesis that this cytoskeletal abnormality is important in the in vivo contractile dysfunction that occurs in experimental aortic stenosis in the adult dog. In 8 dogs in which gradual stenosis of the ascending aorta had caused severe left ventricular (LV) pressure overloading (gradient, 152+/-16 mm Hg) with contractile dysfunction, LV function was measured at baseline and 1 hour after the intravenous administration of colchicine. Cardiocytes obtained by biopsy before and after in vivo colchicine administration were examined in tandem. Microtubule depolymerization restored LV contractile function both in vivo and in vitro. CONCLUSIONS: These and additional corroborative data show that increased cardiocyte microtubule network density is an important mechanism for the ventricular contractile dysfunction that develops in large mammals with adult-onset pressure-overload-induced cardiac hypertrophy.

  2. Assessment of cardiac function and hemodynamics in children and adults with right ventricular pressure overload: role of cardiac magnetic resonance imaging

    NARCIS (Netherlands)

    Romeih, Soha

    2014-01-01

    Accumulating evidence suggests that pressure overload on the right ventricle (RV) leads to RV dysfunction, with considerable morbidity and mortality. Therefore, appropriate RV evaluation is essential because timely intervention may preserve RV function and prevent irreversible RV damage. Currently,

  3. Temporal and Molecular Analyses of Cardiac Extracellular Matrix Remodeling following Pressure Overload in Adiponectin Deficient Mice.

    Directory of Open Access Journals (Sweden)

    Keith Dadson

    Full Text Available Adiponectin, circulating levels of which are reduced in obesity and diabetes, mediates cardiac extracellular matrix (ECM remodeling in response to pressure overload (PO. Here, we performed a detailed temporal analysis of progressive cardiac ECM remodelling in adiponectin knockout (AdKO and wild-type (WT mice at 3 days and 1, 2, 3 and 4 weeks following the induction of mild PO via minimally invasive transverse aortic banding. We first observed that myocardial adiponectin gene expression was reduced after 4 weeks of PO, whereas increased adiponectin levels were detected in cardiac homogenates at this time despite decreased circulating levels of adiponectin. Scanning electron microscopy and Masson's trichrome staining showed collagen accumulation increased in response to 2 and 4 weeks of PO in WT mice, while fibrosis in AdKO mice was notably absent after 2 weeks but highly apparent after 4 weeks of PO. Time and intensity of fibroblast appearance after PO was not significantly different between AdKO and WT animals. Gene array analysis indicated that MMP2, TIMP2, collagen 1α1 and collagen 1α3 were induced after 2 weeks of PO in WT but not AdKO mice. After 4 weeks MMP8 was induced in both genotypes, MMP9 only in WT mice and MMP1α only in AdKO mice. Direct stimulation of primary cardiac fibroblasts with adiponectin induced a transient increase in total collagen detected by picrosirius red staining and collagen III levels synthesis, as well as enhanced MMP2 activity detected via gelatin zymography. Adiponectin also enhanced fibroblast migration and attenuated angiotensin-II induced differentiation to a myofibroblast phenotype. In conclusion, these data indicate that increased myocardial bioavailability of adiponectin mediates ECM remodeling following PO and that adiponectin deficiency delays these effects.

  4. Dasatinib Attenuates Pressure Overload Induced Cardiac Fibrosis in a Murine Transverse Aortic Constriction Model.

    Directory of Open Access Journals (Sweden)

    Sundaravadivel Balasubramanian

    Full Text Available Reactive cardiac fibrosis resulting from chronic pressure overload (PO compromises ventricular function and contributes to congestive heart failure. We explored whether nonreceptor tyrosine kinases (NTKs play a key role in fibrosis by activating cardiac fibroblasts (CFb, and could potentially serve as a target to reduce PO-induced cardiac fibrosis. Our studies were carried out in PO mouse myocardium induced by transverse aortic constriction (TAC. Administration of a tyrosine kinase inhibitor, dasatinib, via an intraperitoneally implanted mini-osmotic pump at 0.44 mg/kg/day reduced PO-induced accumulation of extracellular matrix (ECM proteins and improved left ventricular geometry and function. Furthermore, dasatinib treatment inhibited NTK activation (primarily Pyk2 and Fak and reduced the level of FSP1 positive cells in the PO myocardium. In vitro studies using cultured mouse CFb showed that dasatinib treatment at 50 nM reduced: (i extracellular accumulation of both collagen and fibronectin, (ii both basal and PDGF-stimulated activation of Pyk2, (iii nuclear accumulation of Ki67, SKP2 and histone-H2B and (iv PDGF-stimulated CFb proliferation and migration. However, dasatinib did not affect cardiomyocyte morphologies in either the ventricular tissue after in vivo administration or in isolated cells after in vitro treatment. Mass spectrometric quantification of dasatinib in cultured cells indicated that the uptake of dasatinib by CFb was greater that that taken up by cardiomyocytes. Dasatinib treatment primarily suppressed PDGF but not insulin-stimulated signaling (Erk versus Akt activation in both CFb and cardiomyocytes. These data indicate that dasatinib treatment at lower doses than that used in chemotherapy has the capacity to reduce hypertrophy-associated fibrosis and improve ventricular function.

  5. Possible role of rivaroxaban in attenuating pressure-overload-induced atrial fibrosis and fibrillation.

    Science.gov (United States)

    Kondo, Hidekazu; Abe, Ichitaro; Fukui, Akira; Saito, Shotaro; Miyoshi, Miho; Aoki, Kohei; Shinohara, Tetsuji; Teshima, Yasushi; Yufu, Kunio; Takahashi, Naohiko

    2018-03-01

    Coagulation factor Xa (FXa) promotes thrombus formation and exacerbates inflammation via activation of protease-activated receptor (PAR)-2. We tested the hypothesis of whether administration of direct oral anticoagulant, rivaroxaban, would attenuate transverse aortic constriction (TAC)-induced atrial inflammatory fibrosis and vulnerability to atrial fibrillation (AF) in mice. Ten-week-old male CL57/B6 mice were divided into a sham-operation (CNT) group and TAC-surgery group. These two groups were then subdivided into vehicle (VEH) and rivaroxaban (RVX) treatment (30μg/g/day) groups. We assessed PAR-2 expression in response to TAC-related stimulation using rat cultured cells. TAC-induced left atrial thrombus formation was not observed in the TAC-RVX group. Cardiac PAR-2 upregulation was observed in both TAC groups. In the quantitative analysis of mRNA levels, cardiac PAR-2 upregulation was attenuated in the TAC-RVX group compared to TAC-VEH group. In histological evaluation, the TAC-VEH group showed cardiac inhomogeneous interstitial fibrosis and abundant infiltration of macrophages, which were attenuated by RVX administration. Electrophysiological examination revealed that AF duration in the TAC group was shortened by RVX administration. TAC-induced protein overexpression of monocyte chemoattractant protein-1, and mRNA overexpression of tumor necrosis factor-α, interleukin (IL)-1β and IL-6 in the left atrium was suppressed by RVX treatment. In cardiac fibroblasts, persistent intermittent stretch upregulated PAR-2, which was suppressed by RVX pre-incubation. These observations demonstrate that coagulation FXa inhibitor probably has a cardioprotective effect against pressure-overload-induced atrial remodeling. Copyright © 2017 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  6. Drp1-Dependent Mitochondrial Autophagy Plays a Protective Role Against Pressure Overload-Induced Mitochondrial Dysfunction and Heart Failure.

    Science.gov (United States)

    Shirakabe, Akihiro; Zhai, Peiyong; Ikeda, Yoshiyuki; Saito, Toshiro; Maejima, Yasuhiro; Hsu, Chiao-Po; Nomura, Masatoshi; Egashira, Kensuke; Levine, Beth; Sadoshima, Junichi

    2016-03-29

    Mitochondrial autophagy is an important mediator of mitochondrial quality control in cardiomyocytes. The occurrence of mitochondrial autophagy and its significance during cardiac hypertrophy are not well understood. Mice were subjected to transverse aortic constriction (TAC) and observed at multiple time points up to 30 days. Cardiac hypertrophy developed after 5 days, the ejection fraction was reduced after 14 days, and heart failure was observed 30 days after TAC. General autophagy was upregulated between 1 and 12 hours after TAC but was downregulated below physiological levels 5 days after TAC. Mitochondrial autophagy, evaluated by electron microscopy, mitochondrial content, and Keima with mitochondrial localization signal, was transiently activated at ≈3 to 7 days post-TAC, coinciding with mitochondrial translocation of Drp1. However, it was downregulated thereafter, followed by mitochondrial dysfunction. Haploinsufficiency of Drp1 abolished mitochondrial autophagy and exacerbated the development of both mitochondrial dysfunction and heart failure after TAC. Injection of Tat-Beclin 1, a potent inducer of autophagy, but not control peptide, on day 7 after TAC, partially rescued mitochondrial autophagy and attenuated mitochondrial dysfunction and heart failure induced by overload. Haploinsufficiency of either drp1 or beclin 1 prevented the rescue by Tat-Beclin 1, suggesting that its effect is mediated in part through autophagy, including mitochondrial autophagy. Mitochondrial autophagy is transiently activated and then downregulated in the mouse heart in response to pressure overload. Downregulation of mitochondrial autophagy plays an important role in mediating the development of mitochondrial dysfunction and heart failure, whereas restoration of mitochondrial autophagy attenuates dysfunction in the heart during pressure overload. © 2016 American Heart Association, Inc.

  7. Transient receptor potential vanilloid-3 (TRPV3) activation plays a central role in cardiac fibrosis induced by pressure overload in rats via TGF-β1 pathway.

    Science.gov (United States)

    Liu, Yan; Qi, Hanping; E, Mingyao; Shi, Pilong; Zhang, Qianhui; Li, Shuzhi; Wang, Ye; Cao, Yonggang; Chen, Yunping; Ba, Lina; Gao, Jingquan; Huang, Wei; Sun, Hongli

    2018-02-01

    Cardiac fibrosis is a common pathologic change along with pressure overload. Recent studies indicated that transient receptor potential (TRP) channels played multiple roles in heart. However, the functional role of transient receptor potential vanilloid-3 (TRPV3) in cardiac fibrosis remained unclear. The present study was designed to investigate the relationship between TRPV3 activation and pressure overload-induced cardiac fibrosis. Pressure overload rats were successfully established by abdominal aortic constriction (AAC), and cardiac fibrosis was simulated by 100 nM angiotensin II (Ang II) in neonatal cardiac fibroblasts. Echocardiographic parameters, cardiac fibroblast proliferation, cell cycle, intracellular calcium concentration ([Ca 2+ ] i ), and the protein expressions of collagen I, collagen III, transforming growth factor beta 1 (TGF-β 1 ), cyclin E, and cyclin-dependent kinase 2 (CDK2) were measured. Echocardiographic and histological measurements suggested that the activation of TRPV3 exacerbated the cardiac dysfunction and increased interstitial fibrosis in pressure overload rats. Further results showed that TRPV3 activation upregulated the expressions of collagen I, collagen III, TGF-β 1 , cyclin E, and CDK2 in vivo and in vitro. At the same time, blocking TGF-β 1 pathway could partially reverse the effect of TRPV3 activation. These results suggested that TRPV3 activation exacerbated cardiac fibrosis by promoting cardiac fibroblast proliferation through TGF-β 1 /CDK2/cyclin E pathway in the pressure-overloaded rat hearts.

  8. Coconut Oil Aggravates Pressure Overload-Induced Cardiomyopathy without Inducing Obesity, Systemic Insulin Resistance, or Cardiac Steatosis.

    Science.gov (United States)

    Muthuramu, Ilayaraja; Amin, Ruhul; Postnov, Andrey; Mishra, Mudit; Jacobs, Frank; Gheysens, Olivier; Van Veldhoven, Paul P; De Geest, Bart

    2017-07-18

    Studies evaluating the effects of high-saturated fat diets on cardiac function are most often confounded by diet-induced obesity and by systemic insulin resistance. We evaluated whether coconut oil, containing C12:0 and C14:0 as main fatty acids, aggravates pressure overload-induced cardiomyopathy induced by transverse aortic constriction (TAC) in C57BL/6 mice. Mortality rate after TAC was higher ( p coconut oil diet-fed mice than in standard chow-fed mice (hazard ratio 2.32, 95% confidence interval 1.16 to 4.64) during eight weeks of follow-up. The effects of coconut oil on cardiac remodeling occurred in the absence of weight gain and of systemic insulin resistance. Wet lung weight was 1.76-fold ( p coconut oil mice than in standard chow mice. Myocardial capillary density ( p coconut oil mice than in standard chow mice. Myocardial glucose uptake was 1.86-fold ( p coconut oil mice and was accompanied by higher myocardial pyruvate dehydrogenase levels and higher acetyl-CoA carboxylase levels. The coconut oil diet increased oxidative stress. Myocardial triglycerides and free fatty acids were lower ( p coconut oil mice. In conclusion, coconut oil aggravates pressure overload-induced cardiomyopathy.

  9. The importance of capillary density-stroke work mismatch for right ventricular adaptation to chronic pressure overload.

    Science.gov (United States)

    Noly, Pierre-Emmanuel; Haddad, François; Arthur-Ataam, Jennifer; Langer, Nathaniel; Dorfmüller, Peter; Loisel, Fanny; Guihaire, Julien; Decante, Benoit; Lamrani, Lilia; Fadel, Elie; Mercier, Olaf

    2017-12-01

    Mechanisms of right ventricular (RV) adaptation to chronic pressure overload are not well understood. We hypothesized that a lower capillary density (CD) to stroke work ratio would be associated with more fibrosis and RV maladaptive remodeling. We induced RV chronic pressure overload over a 20-week period in 2 piglet models of pulmonary hypertension; that is, a shunt model (n = 5) and a chronic thromboembolic pulmonary hypertension model (n = 5). We assessed hemodynamic parameters and RV remodeling as well as RV CD, fibrosis, and angiogenic factors expression. Although RV was similarly hypertrophied in both models, maladapted RV remodeling with impaired systolic function was only seen in chronic thromboembolic pulmonary hypertension group members who had lower CD (484 ± 99 vs 1213 ± 74 cap/mm 2 ; P work ratio (0.29 ± 0.07 vs 0.82 ± 0.16; P = .02), higher myocardial fibrosis (15.4% ± 3.8% vs 8.0% ± 2.5%; P work ratio) was associated with greater degree of myocardial fibrosis and RV dysfunction and could be a promising index of RV maladaptation. Further studies are needed to understand the underlying mechanisms. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  10. Probabilistic modeling of material resistance to crack initiation due to hydrided region overloads in CANDU Zr-2.5%Nb pressure tubes

    International Nuclear Information System (INIS)

    Gutkin, L.; Scarth, D.A.

    2014-01-01

    Zr-2.5%Nb pressure tubes in CANDU nuclear reactors are susceptible to hydride-assisted cracking at the locations of stress concentration, such as in-service flaws. Probabilistic methodology is being developed to evaluate such flaws for crack initiation due to hydrided region overloads, which occur when the applied stress acting on a flaw with an existing hydrided region at its tip exceeds the stress at which the hydrided region is formed. As part of this development, probabilistic modeling of pressure tube material resistance to overload crack initiation has been performed on the basis of a set of test data specifically designed to study the effects of non-ratcheting hydride formation conditions and load reduction prior to hydride formation. In the modeling framework, the overload resistance is represented as a power-law function of the material resistance to initiation of delayed hydride cracking under constant loading, where both the overload crack initiation coefficient and the overload crack initiation exponent vary with the flaw geometry. In addition, the overload crack initiation coefficient varies with the extent of load reduction prior to hydride formation as well as the number of non-ratcheting hydride formation thermal cycles. (author)

  11. Probabilistic modeling of material resistance to crack initiation due to hydrided region overloads in CANDU Zr-2.5%Nb pressure tubes

    Energy Technology Data Exchange (ETDEWEB)

    Gutkin, L.; Scarth, D.A. [Kinectrics Inc., Toronto, ON (Canada)

    2014-07-01

    Zr-2.5%Nb pressure tubes in CANDU nuclear reactors are susceptible to hydride-assisted cracking at the locations of stress concentration, such as in-service flaws. Probabilistic methodology is being developed to evaluate such flaws for crack initiation due to hydrided region overloads, which occur when the applied stress acting on a flaw with an existing hydrided region at its tip exceeds the stress at which the hydrided region is formed. As part of this development, probabilistic modeling of pressure tube material resistance to overload crack initiation has been performed on the basis of a set of test data specifically designed to study the effects of non-ratcheting hydride formation conditions and load reduction prior to hydride formation. In the modeling framework, the overload resistance is represented as a power-law function of the material resistance to initiation of delayed hydride cracking under constant loading, where both the overload crack initiation coefficient and the overload crack initiation exponent vary with the flaw geometry. In addition, the overload crack initiation coefficient varies with the extent of load reduction prior to hydride formation as well as the number of non-ratcheting hydride formation thermal cycles. (author)

  12. Long Non-Coding RNA Malat-1 Is Dispensable during Pressure Overload-Induced Cardiac Remodeling and Failure in Mice.

    Directory of Open Access Journals (Sweden)

    Tim Peters

    Full Text Available Long non-coding RNAs (lncRNAs are a class of RNA molecules with diverse regulatory functions during embryonic development, normal life, and disease in higher organisms. However, research on the role of lncRNAs in cardiovascular diseases and in particular heart failure is still in its infancy. The exceptionally well conserved nuclear lncRNA Metastasis associated in lung adenocarcinoma transcript 1 (Malat-1 is a regulator of mRNA splicing and highly expressed in the heart. Malat-1 modulates hypoxia-induced vessel growth, activates ERK/MAPK signaling, and scavenges the anti-hypertrophic microRNA-133. We therefore hypothesized that Malat-1 may act as regulator of cardiac hypertrophy and failure during cardiac pressure overload induced by thoracic aortic constriction (TAC in mice.Absence of Malat-1 did not affect cardiac hypertrophy upon pressure overload: Heart weight to tibia length ratio significantly increased in WT mice (sham: 5.78±0.55, TAC 9.79±1.82 g/mm; p<0.001 but to a similar extend also in Malat-1 knockout (KO mice (sham: 6.21±1.12, TAC 8.91±1.74 g/mm; p<0.01 with no significant difference between genotypes. As expected, TAC significantly reduced left ventricular fractional shortening in WT (sham: 38.81±6.53%, TAC: 23.14±11.99%; p<0.01 but to a comparable degree also in KO mice (sham: 37.01±4.19%, TAC: 25.98±9.75%; p<0.05. Histological hallmarks of myocardial remodeling, such as cardiomyocyte hypertrophy, increased interstitial fibrosis, reduced capillary density, and immune cell infiltration, did not differ significantly between WT and KO mice after TAC. In line, the absence of Malat-1 did not significantly affect angiotensin II-induced cardiac hypertrophy, dysfunction, and overall remodeling. Above that, pressure overload by TAC significantly induced mRNA levels of the hypertrophy marker genes Nppa, Nppb and Acta1, to a similar extend in both genotypes. Alternative splicing of Ndrg2 after TAC was apparent in WT (isoform ratio

  13. Examination of parameters affecting overload fracture behavior of flaw-tip hydrides in Zr-2.5Nb pressure tubes in Candu reactors

    International Nuclear Information System (INIS)

    Cui, J.; Shek, G.K.; Wang, Z.R.

    2007-01-01

    Service-induced flaws in Zr-2.5Nb alloy pressure tubes in Candu (Canada Deuterium Uranium Reactors) nuclear reactors are susceptible to a crack initiation and growth mechanism known as Delayed Hydride Cracking (DHC), which is a repetitive process that involves hydrogen diffusion, hydride precipitation, growth and fracture of a hydride region at the flaw-tip under a constant load. Crack initiation may also occur under another loading condition when the hydride region is subjected to an overload. An overload occurs when the hydride region at the flaw tip is loaded to a stress higher than that at which this region is formed such as when the reactor experiences a transient pressure higher than the normal operating pressure where the hydride region is formed. Flaw disposition requires justification that the hydride region overload will not fracture the hydride region, and initiate DHC. In this work, monotonically increasing load experiments were performed on unirradiated Zr-2.5Nb pressure tube specimens containing simulated debris frets (V-notch) and bearing pad frets (BPF, U-shape notch) to examine overload fracture behavior of flaw-tip hydrides formed under hydride ratcheting conditions. Hydride cracking in the overload tests was detected by the acoustic emission technique and confirmed by post-test metallurgical examination. Test results indicate that the resistance to overload fracture is affected by a number of parameters including hydride formation stress, flaw shape (V-notch vs. BPF) and flaw radius (0.015 mm vs. 0.1 mm). The notch-tip hydride morphologies were examined by optical microscopy and scanning electron microscopy (SEM) which show that they are affected by the hydride formation conditions, resulting in different overload fracture resistance. Finite element stress analyses were also performed to obtain flaw-tip stress distributions for interpretation of the test results. (authors)

  14. Nicorandil prevents right ventricular remodeling by inhibiting apoptosis and lowering pressure overload in rats with pulmonary arterial hypertension.

    Directory of Open Access Journals (Sweden)

    Xiang-Rong Zuo

    Full Text Available BACKGROUND: Most of the deaths among patients with severe pulmonary arterial hypertension (PAH are caused by progressive right ventricular (RV pathological remodeling, dysfunction, and failure. Nicorandil can inhibit the development of PAH by reducing pulmonary artery pressure and RV hypertrophy. However, whether nicorandil can inhibit apoptosis in RV cardiomyocytes and prevent RV remodeling has been unclear. METHODOLOGY/PRINCIPAL FINDINGS: RV remodeling was induced in rats by intraperitoneal injection of monocrotaline (MCT. RV systolic pressure (RVSP was measured at the end of each week after MCT injection. Blood samples were drawn for brain natriuretic peptide (BNP ELISA analysis. The hearts were excised for histopathological, ultrastructural, immunohistochemical, and Western blotting analyses. The MCT-injected rats exhibited greater mortality and less weight gain and showed significantly increased RVSP and RV hypertrophy during the second week. These worsened during the third week. MCT injection for three weeks caused pathological RV remodeling, characterized by hypertrophy, fibrosis, dysfunction, and RV mitochondrial impairment, as indicated by increased levels of apoptosis. Nicorandil improved survival, weight gain, and RV function, ameliorated RV pressure overload, and prevented maladaptive RV remodeling in PAH rats. Nicorandil also reduced the number of apoptotic cardiomyocytes, with a concomitant increase in Bcl-2/Bax ratio. 5-hydroxydecanoate (5-HD reversed these beneficial effects of nicorandil in MCT-injected rats. CONCLUSIONS/SIGNIFICANCE: Nicorandil inhibits PAH-induced RV remodeling in rats not only by reducing RV pressure overload but also by inhibiting apoptosis in cardiomyocytes through the activation of mitochondrial ATP-sensitive K(+ (mitoK(ATP channels. The use of a mitoK(ATP channel opener such as nicorandil for PAH-associated RV remodeling and dysfunction may represent a new therapeutic strategy for the amelioration of RV

  15. Work Overload.

    Science.gov (United States)

    Bateman, Thomas S.

    1980-01-01

    To investigate managerial use of work (or role) overload to increase productivity, the author studied 77 nonclerical white-collar employees and found that work overload had negative effects on productivity, supervisors' ratings, employee attitudes, job satisfaction, and health. He recommends ways for managers and employees to reduce work overload.…

  16. Cytoskeletal role in the transition from compensated to decompensated hypertrophy during adult canine left ventricular pressure overloading

    Science.gov (United States)

    Tagawa, H.; Koide, M.; Sato, H.; Zile, M. R.; Carabello, B. A.; Cooper, G. 4th

    1998-01-01

    Increased microtubule density causes cardiocyte contractile dysfunction in right ventricular (RV) pressure-overload hypertrophy, and these linked phenotypic and contractile abnormalities persist and progress during the transition to failure. Although more severe in cells from failing than hypertrophied RVs, the mechanical defects are normalized in each case by microtubule depolymerization. To define the role of increased microtubule density in left ventricular (LV) pressure-overload hypertrophy and failure, in a given LV we examined ventricular mechanics, sarcomere mechanics, and free tubulin and microtubule levels in control dogs and in dogs with aortic stenosis both with LV hypertrophy alone and with initially compensated hypertrophy that had progressed to LV muscle failure. In comparing initial values with those at study 8 weeks later, dogs with hypertrophy alone had a very substantial increase in LV mass but preservation of a normal ejection fraction and mean systolic wall stress. Dogs with hypertrophy and associated failure had a substantial but lesser increase in LV mass and a reduction in ejection fraction, as well as a marked increase in mean systolic wall stress. Cardiocyte contractile function was equivalent, and unaffected by microtubule depolymerization, in cells from control LVs and those with compensated hypertrophy. In contrast, cardiocyte contractile function in cells from failing LVs was quite depressed but was normalized by microtubule depolymerization. Microtubules were increased only in failing LVs. These contractile and cytoskeletal changes, when assayed longitudinally in a given dog by biopsy, appeared in failing ventricles only when wall stress began to increase and function began to decrease. Thus, the microtubule-based cardiocyte contractile dysfunction characteristic of pressure-hypertrophied myocardium, originally described in the RV, obtains equally in the LV but is shown here to have a specific association with increased wall stress.

  17. Coconut Oil Aggravates Pressure Overload-Induced Cardiomyopathy without Inducing Obesity, Systemic Insulin Resistance, or Cardiac Steatosis

    Directory of Open Access Journals (Sweden)

    Ilayaraja Muthuramu

    2017-07-01

    Full Text Available Studies evaluating the effects of high-saturated fat diets on cardiac function are most often confounded by diet-induced obesity and by systemic insulin resistance. We evaluated whether coconut oil, containing C12:0 and C14:0 as main fatty acids, aggravates pressure overload-induced cardiomyopathy induced by transverse aortic constriction (TAC in C57BL/6 mice. Mortality rate after TAC was higher (p < 0.05 in 0.2% cholesterol 10% coconut oil diet-fed mice than in standard chow-fed mice (hazard ratio 2.32, 95% confidence interval 1.16 to 4.64 during eight weeks of follow-up. The effects of coconut oil on cardiac remodeling occurred in the absence of weight gain and of systemic insulin resistance. Wet lung weight was 1.76-fold (p < 0.01 higher in coconut oil mice than in standard chow mice. Myocardial capillary density (p < 0.001 was decreased, interstitial fibrosis was 1.88-fold (p < 0.001 higher, and systolic and diastolic function was worse in coconut oil mice than in standard chow mice. Myocardial glucose uptake was 1.86-fold (p < 0.001 higher in coconut oil mice and was accompanied by higher myocardial pyruvate dehydrogenase levels and higher acetyl-CoA carboxylase levels. The coconut oil diet increased oxidative stress. Myocardial triglycerides and free fatty acids were lower (p < 0.05 in coconut oil mice. In conclusion, coconut oil aggravates pressure overload-induced cardiomyopathy.

  18. How does pressure overload cause cardiac hypertrophy and dysfunction? High-ouabain affinity cardiac Na+ pumps are crucial.

    Science.gov (United States)

    Blaustein, Mordecai P

    2017-11-01

    Left ventricular hypertrophy is frequently observed in hypertensive patients and is believed to be due to the pressure overload and cardiomyocyte stretch. Three recent reports on mice with genetically engineered Na + pumps, however, have demonstrated that cardiac ouabain-sensitive α 2 -Na + pumps play a key role in the pathogenesis of transaortic constriction-induced hypertrophy. Hypertrophy was delayed/attenuated in mice with mutant, ouabain-resistant α 2 -Na + pumps and in mice with cardiac-selective knockout or transgenic overexpression of α 2 -Na + pumps. The latter, seemingly paradoxical, findings can be explained by comparing the numbers of available (ouabain-free) high-affinity (α 2 ) ouabain-binding sites in wild-type, knockout, and transgenic hearts. Conversely, hypertrophy was accelerated in α 2 -ouabain-resistant (R) mice in which the normally ouabain-resistant α 1 -Na + pumps were mutated to an ouabain-sensitive (S) form (α 1 S/S α 2 R/R or "SWAP" vs. wild-type or α 1 R/R α 2 S/S mice). Furthermore, transaortic constriction-induced hypertrophy in SWAP mice was prevented/reversed by immunoneutralizing circulating endogenous ouabain (EO). These findings show that EO and its receptor, ouabain-sensitive α 2 , are critical factors in pressure overload-induced cardiac hypertrophy. This complements reports linking elevated plasma EO to hypertension, cardiac hypertrophy, and failure in humans and elucidates the underappreciated role of the EO-Na + pump pathway in cardiovascular disease. Copyright © 2017 the American Physiological Society.

  19. ELABELA-APJ axis protects from pressure overload heart failure and angiotensin II-induced cardiac damage.

    Science.gov (United States)

    Sato, Teruki; Sato, Chitose; Kadowaki, Ayumi; Watanabe, Hiroyuki; Ho, Lena; Ishida, Junji; Yamaguchi, Tomokazu; Kimura, Akinori; Fukamizu, Akiyoshi; Penninger, Josef M; Reversade, Bruno; Ito, Hiroshi; Imai, Yumiko; Kuba, Keiji

    2017-06-01

    Elabela/Toddler/Apela (ELA) has been identified as a novel endogenous peptide ligand for APJ/Apelin receptor/Aplnr. ELA plays a crucial role in early cardiac development of zebrafish as well as in maintenance of self-renewal of human embryonic stem cells. Apelin was the first identified APJ ligand, and exerts positive inotropic heart effects and regulates the renin-angiotensin system. The aim of this study was to investigate the biological effects of ELA in the cardiovascular system. Continuous infusion of ELA peptide significantly suppressed pressure overload-induced cardiac hypertrophy, fibrosis and impaired contractility in mice. ELA treatment reduced mRNA expression levels of genes associated with heart failure and fibrosis. The cardioprotective effects of ELA were diminished in APJ knockout mice, indicating that APJ is the key receptor for ELA in the adult heart. Mechanistically, ELA downregulated angiotensin-converting enzyme (ACE) expression in the stressed hearts, whereas it showed little effects on angiotensin-converting enzyme 2 (ACE2) expression, which are distinct from the effects of Apelin. FoxM1 transcription factor, which induces ACE expression in the stressed hearts, was downregulated by ELA but not by Apelin. ELA antagonized angiotensin II-induced hypertension, cardiac hypertrophy, and fibrosis in mice. The ELA-APJ axis protects from pressure overload-induced heart failure possibly via suppression of ACE expression and pathogenic angiotensin II signalling. The different effects of ELA and Apelin on the expression of ACE and ACE2 implicate fine-tuned mechanisms for a ligand-induced APJ activation and downstream signalling. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions please email: journals.permissions@oup.com.

  20. Lack of chemokine signaling through CXCR5 causes increased mortality, ventricular dilatation and deranged matrix during cardiac pressure overload.

    Directory of Open Access Journals (Sweden)

    Anne Waehre

    Full Text Available RATIONALE: Inflammatory mechanisms have been suggested to play a role in the development of heart failure (HF, but a role for chemokines is largely unknown. Based on their role in inflammation and matrix remodeling in other tissues, we hypothesized that CXCL13 and CXCR5 could be involved in cardiac remodeling during HF. OBJECTIVE: We sought to analyze the role of the chemokine CXCL13 and its receptor CXCR5 in cardiac pathophysiology leading to HF. METHODS AND RESULTS: Mice harboring a systemic knockout of the CXCR5 (CXCR5(-/- displayed increased mortality during a follow-up of 80 days after aortic banding (AB. Following three weeks of AB, CXCR5(-/- developed significant left ventricular (LV dilatation compared to wild type (WT mice. Microarray analysis revealed altered expression of several small leucine-rich proteoglycans (SLRPs that bind to collagen and modulate fibril assembly. Protein levels of fibromodulin, decorin and lumican (all SLRPs were significantly reduced in AB CXCR5(-/- compared to AB WT mice. Electron microscopy revealed loosely packed extracellular matrix with individual collagen fibers and small networks of proteoglycans in AB CXCR5(-/- mice. Addition of CXCL13 to cultured cardiac fibroblasts enhanced the expression of SLRPs. In patients with HF, we observed increased myocardial levels of CXCR5 and SLRPs, which was reversed following LV assist device treatment. CONCLUSIONS: Lack of CXCR5 leads to LV dilatation and increased mortality during pressure overload, possibly via lack of an increase in SLRPs. This study demonstrates a critical role of the chemokine CXCL13 and CXCR5 in survival and maintaining of cardiac structure upon pressure overload, by regulating proteoglycans essential for correct collagen assembly.

  1. Lung volumes and maximal respiratory pressures in collegiate swimmers and runners.

    Science.gov (United States)

    Cordain, L; Tucker, A; Moon, D; Stager, J M

    1990-03-01

    To determine whether respiratory muscle strength is related to pulmonary volume differences in athletes and nonathletes, 11 intercollegiate female swimmers, 11 female cross-country runners, and two nonathletic control groups, matched to the athletes in height and age, were evaluated for pulmonary parameters including maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax). Swimmers exhibited larger (p less than .05) vital capacities (VC), residual lung volumes (RV), inspiratory capacities (IC), and functional residual capacities (FRC) than both the runners or the controls but no difference (p greater than .05) in either PImax or inspiratory flow (FIV 25%-75%). Timed expiratory volumes (FEV 0.5 and FEV 1.0) were significantly (p less than .05) lower in the swimmers than in the controls. These data suggest that an adaptational growth may be responsible, in part, for the augmented static lung volumes demonstrated in swimmers.

  2. Uridine Adenosine Tetraphosphate-Induced Coronary Relaxation Is Blunted in Swine With Pressure Overload: A Role for Vasoconstrictor Prostanoids.

    Science.gov (United States)

    Zhou, Zhichao; Lankhuizen, Inge M; van Beusekom, Heleen M; Cheng, Caroline; Duncker, Dirk J; Merkus, Daphne

    2018-01-01

    Plasma levels of the vasoactive substance uridine adenosine tetraphosphate (Up 4 A) are elevated in hypertensive patients and Up 4 A-induced vascular contraction is exacerbated in various arteries isolated from hypertensive animals, suggesting a potential role of Up 4 A in development of hypertension. We previously demonstrated that Up 4 A produced potent and partially endothelium-dependent relaxation in the porcine coronary microvasculature. Since pressure-overload is accompanied by structural abnormalities in the coronary microvasculature as well as by endothelial dysfunction, we hypothesized that pressure-overload blunts the coronary vasodilator response to Up 4 A, and that the involvement of purinergic receptors and endothelium-derived factors is altered. The effects of Up 4 A were investigated using wire-myography in isolated coronary small arteries from Sham-operated swine and swine with prolonged (8 weeks) pressure overload of the left ventricle induced by aortic banding (AoB). Expression of purinergic receptors and endothelium-derived factors was assessed in isolated coronary small arteries using real-time PCR. Up 4 A (10 -9 to 10 -5 M) failed to produce contraction in isolated coronary small arteries from either Sham or AoB swine, but produced relaxation in preconstricted arteries, which was significantly blunted in AoB compared to Sham. Blockade of purinergic P1, and P2 receptors attenuated Up 4 A-induced coronary relaxation more, while the effect of P2X 1 -blockade was similar and the effects of A 2A - and P2Y 1 -blockade were reduced in AoB as compared to Sham. mRNA expression of neither A1, A2, A3, nor P2X 1 , P2X 7 , P2Y 1 , P2Y 2 , nor P2Y 6 -receptors was altered in AoB as compared to Sham, while P2Y 12 expression was higher in AoB. eNOS inhibition attenuated Up 4 A-induced coronary relaxation in both Sham and AoB. Additional blockade of cyclooxygenase enhanced Up 4 A-induced coronary relaxation in AoB but not Sham swine, suggesting the involvement

  3. Pressure overload stimulated cardiac hypertrophy leads to a rapid decrease in the mRNA for creatine kinase

    International Nuclear Information System (INIS)

    Boheler, K.; Popovich, B.; Dillmann, W.H.

    1987-01-01

    Cardiac hypertrophy (CH) leads to a decrease in creatine kinase (CK) enzymatic activity. To determine if the mRNA for CK also decreases with CH, they performed the following studies. Cardiac RNA was isolated from rats subjected to either abdominal aortic stenosis (AS) or sham surgery. Through Northern blot analysis, total cardiac RNA was quantitated with a CK specific 32 P-labelled cDNA clone. At 3 and 8 days post-constriction, the mRNA for CK decreases by 54.6 +/- 7% and 65.3 +/- 18% respectively, whereas the heart weight increases by 19% and 37% relative to controls. Further studies indicate that CK mRNA also decreases by 41.8% in hypothyroid rats (Tx) but decreases by a total of 68.1% in Tx rats subjected to 8 days of AS. Pressure overload stimulated CH leads to a rapid decrease in CK mRNA in normal and Tx rats. This CK mRNA decrease may account for the decreased efficiency of contraction seen in CH

  4. ω-3 Polyunsaturated fatty acids prevent pressure overload-induced ventricular dilation and decrease in mitochondrial enzymes despite no change in adiponectin

    Directory of Open Access Journals (Sweden)

    O'Shea Karen M

    2010-09-01

    Full Text Available Abstract Background Pathological left ventricular (LV hypertrophy frequently progresses to dilated heart failure with suppressed mitochondrial oxidative capacity. Dietary marine ω-3 polyunsaturated fatty acids (ω-3 PUFA up-regulate adiponectin and prevent LV dilation in rats subjected to pressure overload. This study 1 assessed the effects of ω-3 PUFA on LV dilation and down-regulation of mitochondrial enzymes in response to pressure overload; and 2 evaluated the role of adiponectin in mediating the effects of ω-3 PUFA in heart. Methods Wild type (WT and adiponectin-/- mice underwent transverse aortic constriction (TAC and were fed standard chow ± ω-3 PUFA for 6 weeks. At 6 weeks, echocardiography was performed to assess LV function, mice were terminated, and mitochondrial enzyme activities were evaluated. Results TAC induced similar pathological LV hypertrophy compared to sham mice in both strains on both diets. In WT mice TAC increased LV systolic and diastolic volumes and reduced mitochondrial enzyme activities, which were attenuated by ω-3 PUFA without increasing adiponectin. In contrast, adiponectin-/- mice displayed no increase in LV end diastolic and systolic volumes or decrease in mitochondrial enzymes with TAC, and did not respond to ω-3 PUFA. Conclusion These findings suggest ω-3 PUFA attenuates cardiac pathology in response to pressure overload independent of an elevation in adiponectin.

  5. Vagus nerve stimulation mitigates intrinsic cardiac neuronal remodeling and cardiac hypertrophy induced by chronic pressure overload in guinea pig

    Science.gov (United States)

    Beaumont, Eric; Wright, Gary L.; Southerland, Elizabeth M.; Li, Ying; Chui, Ray; KenKnight, Bruce H.; Armour, J. Andrew

    2016-01-01

    Our objective was to determine whether chronic vagus nerve stimulation (VNS) mitigates pressure overload (PO)-induced remodeling of the cardioneural interface. Guinea pigs (n = 48) were randomized to right or left cervical vagus (RCV or LCV) implant. After 2 wk, chronic left ventricular PO was induced by partial (15–20%) aortic constriction. Of the 31 animals surviving PO induction, 10 were randomized to RCV VNS, 9 to LCV VNS, and 12 to sham VNS. VNS was delivered at 20 Hz and 1.14 ± 0.03 mA at a 22% duty cycle. VNS commenced 10 days after PO induction and was maintained for 40 days. Time-matched controls (n = 9) were evaluated concurrently. Echocardiograms were obtained before and 50 days after PO. At termination, intracellular current-clamp recordings of intrinsic cardiac (IC) neurons were studied in vitro to determine effects of therapy on soma characteristics. Ventricular cardiomyocyte sizes were assessed with histology along with immunoblot analysis of selected proteins in myocardial tissue extracts. In sham-treated animals, PO increased cardiac output (34%, P < 0.004), as well as systolic (114%, P < 0.04) and diastolic (49%, P < 0.002) left ventricular volumes, a hemodynamic response prevented by VNS. PO-induced enhancements of IC synaptic efficacy and muscarinic sensitivity of IC neurons were mitigated by chronic VNS. Increased myocyte size, which doubled in PO (P < 0.05), was mitigated by RCV. PO hypertrophic myocardium displayed decreased glycogen synthase (GS) protein levels and accumulation of the phosphorylated (inactive) form of GS. These PO-induced changes in GS were moderated by left VNS. Chronic VNS targets IC neurons accompanying PO to obtund associated adverse cardiomyocyte remodeling. PMID:26993230

  6. Miso (Japanese soybean paste) soup attenuates salt-induced sympathoexcitation and left ventricular dysfunction in mice with chronic pressure overload.

    Science.gov (United States)

    Ito, Koji; Hirooka, Yoshitaka; Sunagawa, Kenji

    2014-02-01

    The hypothalamic mineralocorticoid receptor (MR)-angiotensin II type 1 receptor (AT1R) pathway is activated in mice with chronic pressure overload (CPO). When this activation is combined with high salt intake, it leads to sympathoexcitation, hypertension, and left ventricular (LV) dysfunction. Salt intake is thus an important factor that contributes to heart failure. Miso, a traditional Japanese food made from fermented soybeans, rice, wheat, or oats, can attenuate salt-induced hypertension in rats. However, its effects on CPO mice with salt-induced sympathoexcitation and LV dysfunction are unclear. Here, we investigated whether miso has protective effects in these mice. We also evaluated mechanisms associated with the hypothalamic MR-AT1R pathway. Aortic banding was used to produce CPO, and a sham operation was performed for controls. At 2 weeks after surgery, the mice were given water containing high NaCl levels (0.5%, 1.0%, and 1.5%) for 4 weeks. The high salt loading in CPO mice increased excretion of urinary norepinephrine (uNE), a marker of sympathetic activity, in an NaCl concentration-dependent manner; however, this was not observed in Sham mice. Subsequently, CPO mice were administered 1.0% NaCl water (CPO-H) or miso soup (1.0% NaCl equivalent, CPO-miso). The expression of hypothalamic MR, serum glucocorticoid-induced kinase-1 (SGK-1), and AT1R was higher in the CPO-H mice than in the Sham mice; however, the expression of these proteins was attenuated in the CPO-miso group. Although the CPO-miso mice had higher sodium intake, salt-induced sympathoexcitation was lower in these mice than in the CPO-H group. Our findings indicate that regular intake of miso soup attenuates salt-induced sympathoexcitation in CPO mice via inhibition of the hypothalamic MR-AT1R pathway.

  7. Chronic activation of the low affinity site of β1-adrenoceptors stimulates haemodynamics but exacerbates pressure-overload cardiac remodelling

    Science.gov (United States)

    Kiriazis, Helen; Tugiono, Niquita; Xu, Qi; Gao, Xiao-Ming; Jennings, Nicole L; Ming, Ziqui; Su, Yidan; Klenowski, Paul; Summers, Roger J; Kaumann, Alberto; Molenaar, Peter; Du, Xiao-Jun

    2013-01-01

    BACKGROUND AND PURPOSE The β1-adrenoceptor has at least two binding sites, high and low affinity sites (β1H and β1L, respectively), which mediate cardiostimulation. While β1H-adrenoceptor can be blocked by all clinically used β-blockers, β1L-adrenoceptor is relatively resistant to blockade. Thus, chronic β1L-adrenoceptor activation may mediate persistent cardiostimulation, despite the concurrent blockade of β1H-adrenoceptors. Hence, it is important to determine the potential significance of β1L-adrenoceptors in vivo, particularly in pathological situations. EXPERIMENTAL APPROACH C57Bl/6 male mice were used. Chronic (4 or 8 weeks) β1L-adrenoceptor activation was achieved by treatment, via osmotic mini pumps, with (-)-CGP12177 (10 mg·kg−1·day−1). Cardiac function was assessed by echocardiography and micromanometry. KEY RESULTS (-)-CGP12177 treatment of healthy mice increased heart rate and left ventricular (LV) contractility. (-)-CGP12177 treatment of mice subjected to transverse aorta constriction (TAC), during weeks 4–8 or 4–12 after TAC, led to a positive inotropic effect and exacerbated fibrogenic signalling while cardiac hypertrophy tended to be more severe. (-)-CGP12177 treatment of mice with TAC also exacerbated the myocardial expression of hypertrophic, fibrogenic and inflammatory genes compared to untreated TAC mice. Washout of (-)-CGP12177 revealed a more pronounced cardiac dysfunction after 12 weeks of TAC. CONCLUSIONS AND IMPLICATIONS β1L-adrenoceptor activation provides functional support to the heart, in both normal and pathological (pressure overload) situations. Sustained β1L-adrenoceptor activation in the diseased heart exacerbates LV remodelling and therefore may promote disease progression from compensatory hypertrophy to heart failure. PMID:23750586

  8. Edaravone inhibits pressure overload-induced cardiac fibrosis and dysfunction by reducing expression of angiotensin II AT1 receptor

    Directory of Open Access Journals (Sweden)

    Zhang WW

    2017-10-01

    mmHg, p<0.05 and ejection fraction (82%±3% vs 60%±5%, p<0.05. Treatment with telmisartan provided a comparable level of protection as compared with edaravone in all the parameters measured. Taken together, edaravone treatment ameliorates cardiac fibrosis and improves left ventricular function in the pressure overload rat model, potentially via suppressing the AT1 receptor-mediated signaling pathways. These data indicate that edaravone might be selected in combination with other existing drugs in preventing progression of cardiac dysfunction in heart failure. Keywords: angiotensin II receptor, cardiac fibrosis, cardiac function, edaravone, heart failure

  9. Effects of induced Na+/Ca2+ exchanger overexpression on the spatial distribution of L-type Ca2+ channels and junctophilin-2 in pressure-overloaded hearts.

    Science.gov (United States)

    Ujihara, Yoshihiro; Mohri, Satoshi; Katanosaka, Yuki

    2016-11-25

    The Na + /Ca 2+ exchanger 1 (NCX1) is an essential Ca 2+ efflux system in cardiomyocytes. Although NCX1 is distributed throughout the sarcolemma, a subpopulation of NCX1 is localized to transverse (T)-tubules. There is growing evidence that T-tubule disorganization is a causal event that shifts the transition from hypertrophy to heart failure (HF). However, the detailed molecular mechanisms have not been clarified. Previously, we showed that induced NCX1 expression in pressure-overloaded hearts attenuates defective excitation-contraction coupling and HF progression. Here, we examined the effects of induced NCX1 overexpression on the spatial distribution of L-type Ca 2+ channels (LTCCs) and junctophilin-2 (JP2), a structural protein that connects the T-tubule and sarcoplasmic reticulum membrane, in pressure-overloaded hearts. Quantitative analysis showed that the regularity of NCX1 localization was significantly decreased at 8 weeks after transverse aortic constriction (TAC)-surgery; however, T-tubule organization and the regularities of LTCC and JP2 immunofluorescent signals were maintained at this time point. These observations demonstrated that release of NCX1 from the T-tubule area occurred before the onset of T-tubule disorganization and LTCC and JP2 mislocalization. Moreover, induced NCX1 overexpression at 8 weeks post-TAC not only recovered NCX1 regularity but also prevented the decrease in LTCC and JP2 regularities at 16 weeks post-TAC. These results suggested that NCX1 may play an important role in the proper spatial distribution of LTCC and JP2 in T-tubules in the context of pressure-overloading. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Myocardial fatty acid imaging with 123I-BMIPP in patients with chronic right ventricular pressure overload. Clinical significance of reduced uptake in interventricular septum

    International Nuclear Information System (INIS)

    Hori, Yoshiro; Ishida, Yoshio; Fukuchi, Kazuki; Hayashida, Kouhei; Takamiya, Makoto

    2002-01-01

    Regionally reduced 123 I-beta-methyliodophenyl pentadecanoic acid (123I-BMIPP) uptake in the interventricular septum (SEP) is observed in some patients with chronic right ventricular (RV) pressure overload. We studied the significance of this finding by comparing it with mean pulmonary arterial pressure (mPAP). 123 I-BMIPP SPECT imaging was carried out in 21 patients with pulmonary hypertension (PH; 51+-14 years; 11 men and 10 women; 7 with primary pulmonary hypertension, 11 with pulmonary thromboembolism, and 3 with atrial septal defect). mPAP ranged from 25 to 81 mmHg (49±16 mmHg). Using a midventricular horizontal long-axis plane, regional BMIPP distributions in the RV free wall and SEP were estimated by referring to those in the LV free wall. Count ratios of the RV free wall and SEP to the LV free wall (RV/LV, SEP/LV) were determined by ROI analysis. RV/LV showed a linear correlation with mPAP (r=0.42). However, SEP/LV was inversely correlated with mPAP (r=-0.49). When SEP/RV was compared among three regions of SEP in each patient, basal SEP/RV was most sensitively decreased in response to increased mPAP (r=-0.70). These results suggest that the assessment of septal tracer uptake in 123 I-BMIPP SPECT imaging is useful for evaluating the severity of RV pressure overload in patients with PH. (author)

  11. Validation of a protocol to evaluate maximal expiratory pressure using a pressure transducer and a signal conditioner

    Directory of Open Access Journals (Sweden)

    Viviane Soares

    2011-09-01

    Full Text Available The respiratory muscles can present fatigue and even chronic inability to generate force. So, reliable devices are necessary to their evaluation. The aim of this study is to evaluate the MEP (Maximal Expiratory Pressure values of individuals between 20 and 25 years old and to validate a protocol using a pressure transducer and a signal conditioner comparing it with the digital manometer. We evaluated the MEP of 10 participants. They remained seated and made six respiratory maneuvers from Total Lung Capacity (TLC to Residual Volume (RV. The results in the study showed no statistically significant differences when compared to values reported in the literature, and that the pressure transducer provides reliable values for MEP.Os músculos respiratórios podem apresentar fadiga e até mesmo a incapacidade crônica na geração de força, sendo necessários dispositivos confiáveis para sua avaliação. O objetivo deste estudo foi avaliar a pressão expiratória máxima (PeMáx de indivíduos entre 20 e 25 anos e validar um protocolo que utiliza um transdutor de pressão e um condicionador de sinais comparando-o com a manovacuometria. Foram avaliadas a PeMáx de 10 participantes. Estes permaneceram sentados e realizaram seis manobras respiratórias a partir da capacidade pulmonar total (CPT até o volume residual (VR. Os resultados do estudo não apresentaram diferenças estatisticamente significativas quando comparados com os valores de normalidade descritos na literatura e mostraram que o transdutor de pressão fornece valores confiáveis para Pe máx.

  12. Unidirectional Expiratory Valve Method to Assess Maximal Inspiratory Pressure in Individuals without Artificial Airway.

    Directory of Open Access Journals (Sweden)

    Samantha Torres Grams

    Full Text Available Maximal Inspiratory Pressure (MIP is considered an effective method to estimate strength of inspiratory muscles, but still leads to false positive diagnosis. Although MIP assessment with unidirectional expiratory valve method has been used in patients undergoing mechanical ventilation, no previous studies investigated the application of this method in subjects without artificial airway.This study aimed to compare the MIP values assessed by standard method (MIPsta and by unidirectional expiratory valve method (MIPuni in subjects with spontaneous breathing without artificial airway. MIPuni reproducibility was also evaluated.This was a crossover design study, and 31 subjects performed MIPsta and MIPuni in a random order. MIPsta measured MIP maintaining negative pressure for at least one second after forceful expiration. MIPuni evaluated MIP using a unidirectional expiratory valve attached to a face mask and was conducted by two evaluators (A and B at two moments (Tests 1 and 2 to determine interobserver and intraobserver reproducibility of MIP values. Intraclass correlation coefficient (ICC[2,1] was used to determine intraobserver and interobserver reproducibility.The mean values for MIPuni were 14.3% higher (-117.3 ± 24.8 cmH2O than the mean values for MIPsta (-102.5 ± 23.9 cmH2O (p<0.001. Interobserver reproducibility assessment showed very high correlation for Test 1 (ICC[2,1] = 0.91, and high correlation for Test 2 (ICC[2,1] = 0.88. The assessment of the intraobserver reproducibility showed high correlation for evaluator A (ICC[2,1] = 0.86 and evaluator B (ICC[2,1] = 0.77.MIPuni presented higher values when compared with MIPsta and proved to be reproducible in subjects with spontaneous breathing without artificial airway.

  13. Role of heat shock transcription factor 1(HSF1)-upregulated macrophage in ameliorating pressure overload-induced heart failure in mice.

    Science.gov (United States)

    Du, Peizhao; Chang, Yaowei; Dai, Fangjie; Wei, Chunyan; Zhang, Qi; Li, Jiming

    2018-08-15

    In order to explore the role of macrophages in HSF1-mediated alleviation of heart failure, mice model of pressure overload-induced heart failure was established using transverse aortic constriction (TAC). Changes in cardiac function and morphology were studied in TAC and SHAM groups using ultrasonic device, tissue staining, electron microscopy, real-time quantitative polymerase chain reaction (RT-QPCR), and Western blotting. We found that mice in the TAC group showed evidence of impaired cardiac function and aggravation of fibrosis on ultrasonic and histopathological examination when compared to those in the SHAM group. The expressions of HSF1, LC3II/LC3I, Becline-1 and HIF-1, as well as autophagosome formation in TAC group were greater than that in SHAM group. On sub-group analyses in the TAC group, improved cardiac function and alleviation of fibrosis was observed in the HSF1 TG subgroup as compared to that in the wild type subgroup. Expressions of LC3II/LC3I, Becline-1 and HIF-1, too showed an obvious increase; and increased autophagosome formation was observed on electron microscopy. Opposite results were observed in the HSF1 KO subgroup. These results collectively suggest that in the pressure overload heart failure model, HSF1 promoted formation of macrophages by inducing upregulation of HIF-1 expression, through which heart failure was ameliorated. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Evaluation of right ventricular function using gated equilibrium blood pool radionuclide ventriculography in patients with congenital volume and pressure overload late after surgical repair

    International Nuclear Information System (INIS)

    Hirata, Nobuaki; Sakakibara, Tetsuo; Watanabe, Shinichiro; Nomura, Fumikazu; Akamatsu, Hiroki; Matsumura, Yasushi; Yamamoto, Kazuhiro; Sasaki, Jiro; Kodama, Kazuhisa

    1991-01-01

    The effects of congenital right ventricular pressure and volume overload were studied in 3 patients with pulmonary stenosis, 7 with atrial septal defect and 6 with atrial septal defect plus pulmonary stenosis late after successful surgical correction. Gated equilibrium blood pool radionuclide ventriculography was used to measure right ventricular function at rest and during exercise and to compare it with eight normal subjects. Right ventricular ejection fractions at rest and during exercise were measured to be 61±9% and 66±13%, respectively, in the group with pulmonary stenosis, 49±7% and 54±8% in the group with atrial septal defect, and 65±13% and 69±13% in the group with atrial septal defect plus pulmonary stenosis. The values in the groups with pulmonary stenosis and atrial septal defect plus pulmonary stenosis were significantly higher than the control subjects (45±5% and 51±5%, p<0.01). The peak filling rate at rest and during exercise was also significantly higher in the groups with pulmonary stenosis and atrial septal defect plus pulmonary stenosis than in controls (at rest, 2.72±0.72, 2.53±0.94 vs. 1.64±0.24 p<0.05; during exercise, 4.38±1.23, 4.13±1.18 vs. 2.25±0.62, p<0.01). When patients with right ventricular systolic pressure equal to or greater than left ventricular systolic pressure and those with right ventricular systolic pressure less than left ventricular systolic pressure were compared, the right ventricular ejection fraction and peak filling rate were greater with the higher pressure at rest (71±10% and 3.12±0.81% vs. 55±3% and 2.30±0.27, p<0.05) and during exercise (75±11% and 4.86±1.01 vs. 59±3% and 2.61±0.35, p<0.05). Postoperative right ventricular hyperfunction may be due to preoperative pressure, but not volume, overload. (author)

  15. Information overload and data overload in lexicography

    DEFF Research Database (Denmark)

    Gouws, Rufus H.; Tarp, Sven

    2017-01-01

    the often uncritical inclusion of too much data. This paper discusses the general term information overload and its lexicographical counterpart data overload. Different types of data overload are identified and the problems users have when retrieving the necessary information from dictionary articles...

  16. Inhibition of PKC-dependent extracellular Ca2+ entry contributes to the depression of contractile activity in long-term pressure-overloaded endothelium-denuded rat aortas

    International Nuclear Information System (INIS)

    Padilla, J.; López, R.M.; López, P.; Castillo, M.C.; Querejeta, E.; Ruiz, A.; Castillo, E.F.

    2014-01-01

    We examined the contractile responsiveness of rat thoracic aortas under pressure overload after long-term suprarenal abdominal aortic coarctation (lt-Srac). Endothelium-dependent angiotensin II (ANG II) type 2 receptor (AT 2 R)-mediated depression of contractions to ANG II has been reported in short-term (1 week) pressure-overloaded rat aortas. Contractility was evaluated in the aortic rings of rats subjected to lt-Srac or sham surgery (Sham) for 8 weeks. ANG I and II levels and AT 2 R protein expression in the aortas of lt-Srac and Sham rats were also evaluated. lt-Srac attenuated the contractions of ANG II and phenylephrine in the aortas in an endothelium-independent manner. However, lt-Srac did not influence the transient contractions induced in endothelium-denuded aortic rings by ANG II, phenylephrine, or caffeine in Ca 2+ -free medium or the subsequent tonic constrictions induced by the addition of Ca 2+ in the absence of agonists. Thus, the contractions induced by Ca 2+ release from intracellular stores and Ca 2+ influx through stored-operated channels were not inhibited in the aortas of lt-Srac rats. Potassium-elicited contractions in endothelium-denuded aortic rings of lt-Srac rats remained unaltered compared with control tissues. Consequently, the contractile depression observed in aortic tissues of lt-Srac rats cannot be explained by direct inhibition of voltage-operated Ca 2+ channels. Interestingly, 12-O-tetradecanoylphorbol-13-acetate-induced contractions in endothelium-denuded aortic rings of lt-Srac rats were depressed in the presence but not in the absence of extracellular Ca 2+ . Neither levels of angiotensins nor of AT 2 R were modified in the aortas after lt-Srac. The results suggest that, in rat thoracic aortas, lt-Srac selectively inhibited protein kinase C-mediated activation of contraction that is dependent on extracellular Ca 2+ entry

  17. Toll‐Like Receptor‐2 Mediates Adaptive Cardiac Hypertrophy in Response to Pressure Overload Through Interleukin‐1β Upregulation via Nuclear Factor κB Activation

    Science.gov (United States)

    Higashikuni, Yasutomi; Tanaka, Kimie; Kato, Megumi; Nureki, Osamu; Hirata, Yasunobu; Nagai, Ryozo; Komuro, Issei; Sata, Masataka

    2013-01-01

    Background Inflammation is induced in the heart during the development of cardiac hypertrophy. The initiating mechanisms and the role of inflammation in cardiac hypertrophy, however, remain unclear. Toll‐like receptor‐2 (TLR2) recognizes endogenous molecules that induce noninfectious inflammation. Here, we examined the role of TLR2‐mediated inflammation in cardiac hypertrophy. Methods and Results At 2 weeks after transverse aortic constriction, Tlr2−/− mice showed reduced cardiac hypertrophy and fibrosis with greater left ventricular dilatation and impaired systolic function compared with wild‐type mice, which indicated impaired cardiac adaptation in Tlr2−/− mice. Bone marrow transplantation experiment revealed that TLR2 expressed in the heart, but not in bone marrow–derived cells, is important for cardiac adaptive response to pressure overload. In vitro experiments demonstrated that TLR2 signaling can induce cardiomyocyte hypertrophy and fibroblast and vascular endothelial cell proliferation through nuclear factor–κB activation and interleukin‐1β upregulation. Systemic administration of a nuclear factor–κB inhibitor or anti–interleukin‐1β antibodies to wild‐type mice resulted in impaired adaptive cardiac hypertrophy after transverse aortic constriction. We also found that heat shock protein 70, which was increased in murine plasma after transverse aortic constriction, can activate TLR2 signaling in vitro and in vivo. Systemic administration of anti–heat shock protein 70 antibodies to wild‐type mice impaired adaptive cardiac hypertrophy after transverse aortic constriction. Conclusions Our results demonstrate that TLR2‐mediated inflammation induced by extracellularly released heat shock protein 70 is essential for adaptive cardiac hypertrophy in response to pressure overload. Thus, modulation of TLR2 signaling in the heart may provide a novel strategy for treating heart failure due to inadequate adaptation to hemodynamic

  18. Splenectomy exacerbates atrial inflammatory fibrosis and vulnerability to atrial fibrillation induced by pressure overload in rats: Possible role of spleen-derived interleukin-10.

    Science.gov (United States)

    Kondo, Hidekazu; Takahashi, Naohiko; Gotoh, Koro; Fukui, Akira; Saito, Shotaro; Aoki, Kohei; Kume, Osamu; Shinohara, Tetsuji; Teshima, Yasushi; Saikawa, Tetsunori

    2016-01-01

    The spleen is important for cardiac remodeling induced by myocardial infarction. However, the role of the spleen in inflammatory atrial fibrosis induced by pressure overload is unknown. The purpose of this study was to investigate whether splenectomy (SPX) attenuates or exacerbates pressure overload-induced atrial inflammatory fibrosis and vulnerability to atrial fibrillation (AF) in rats. Male Sprague-Dawley rats (6 weeks old) were divided into Sham+Sham, Sham+SPX, abdominal aortic constriction (AAC)+Sham, and AAC+SPX groups, and were evaluated for inflammation, fibrosis, and AF on days 2, 4, 14, and 28. On day 4, an AAC-induced rise in interleukin-10 (IL-10) level was observed in the spleen, serum, and left atrium (LA), with SPX showing inhibitory effects in the latter 2 instances. In addition, AAC-induced M2 macrophage recruitment into the LA was decreased by SPX, as determined by immunofluorescence labeling (P <.05). On day 28, AAC-induced heterogeneous interstitial fibrosis of the LA was enhanced by SPX (P <.05). Electrophysiologic recordings revealed that the duration of AF and prolongation of interatrial conduction time induced by AAC were increased by SPX (P < .01 and P <.05, respectively). Furthermore, in the AAC+SPX group, the number of macrophages infiltrating into the LA on day 2 was marginal, but increased on day 28 relative to the AAC+Sham group. IL-10 administration attenuated the AAC-induced atrial remodeling that was aggravated by SPX. The study results suggest that SPX exacerbates AAC-induced inflammatory atrial fibrosis and increases vulnerability to AF after 4 weeks, likely because of depletion of spleen-derived IL-10. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  19. Lipocalin-2 induces NLRP3 inflammasome activation via HMGB1 induced TLR4 signaling in heart tissue of mice under pressure overload challenge.

    Science.gov (United States)

    Song, Erfei; Jahng, James Ws; Chong, Lisa P; Sung, Hye K; Han, Meng; Luo, Cuiting; Wu, Donghai; Boo, Stellar; Hinz, Boris; Cooper, Matthew A; Robertson, Avril Ab; Berger, Thorsten; Mak, Tak W; George, Isaac; Schulze, P Christian; Wang, Yu; Xu, Aimin; Sweeney, Gary

    2017-01-01

    Lipocalin-2 (also known as NGAL) levels are elevated in obesity and diabetes yet relatively little is known regarding effects on the heart. We induced pressure overload (PO) in mice and found that lipocalin-2 knockout (LKO) mice exhibited less PO-induced autophagy and NLRP3 inflammasome activation than Wt. PO-induced mitochondrial damage was reduced and autophagic flux greater in LKO mice, which correlated with less cardiac dysfunction. All of these observations were negated upon adenoviral-mediated restoration of normal lipocalin-2 levels in LKO. Studies in primary cardiac fibroblasts indicated that lipocalin-2 enhanced priming and activation of NLRP3-inflammasome, detected by increased IL-1β, IL-18 and Caspase-1 activation. This was attenuated in cells isolated from NLRP3-deficient mice or upon pharmacological inhibition of NLRP3. Furthermore, lipocalin-2 induced release of HMGB1 from cells and NLRP3-inflammasome activation was attenuated by TLR4 inhibition. We also found evidence of increased inflammasome activation and reduced autophagy in cardiac biopsy samples from heart failure patients. Overall, this study provides new mechanistic insight on the detrimental role of lipocalin-2 in the development of cardiac dysfunction.

  20. Regional myocardial extraction of a radioiodinated branched chain fatty acid during right ventricular pressure overload due to acute pulmonary hypertension

    International Nuclear Information System (INIS)

    Hurford, W.; Lowenstein, E.; Zapol, W.; Barlai-Kovach, M.; Livni, E.; Elmaleh, D.R.; Strauss, H.W.

    1985-01-01

    To determine whether branched chain fatty acid extraction is reduced during right ventricular (RV) dysfunction due to acute pulmonary artery hypertension, studies were done in 6 anesthetized dogs. Regional branched chain fatty acid extraction was measured by comparing the myocardial uptake of I-125 labeled 15-[p-(iodophenyl)]-3-methylpentadecanoic acid (I-PDA) to myocardial blood flow. Acute pulmonary hypertension was induced by incremental intravenous injection of 100 micron diameter glass beads into six pentobarbital anesthetized, mechanically ventilated dogs. Myocardial blood flow was measured by radiolabeled microspheres both under baseline conditions and during pulmonary hypertension. Mean RV pressure rose from 12 +- 2 (mean +- SEM) to 30 +-3mmHg resulting in a 225 +- 16% increase in RV stroke work. RV ejection fraction, as assessed by gated blood pool scans fell from 39 +- 2 to 18 +- 2%. Left ventricular (LV) pressures, stroke work and ejection fraction were unchanged. Myocardial blood flow increased 132 + 59% in the RV free wall and 67 +- 22% in the RV septum. LV blood flow was unchanged. Despite increased RV work and myocardial blood flow, no differences were noted in the branched chain fatty acid extraction ratios among LV or RV free walls or septum. The authors conclude that early RV dysfunction associated with pulmonary artery hypertension is not due to inadequate myocardial blood flow or branched chain fatty acid extraction

  1. Association of Right Ventricular Pressure and Volume Overload with Non-Ischemic Septal Fibrosis on Cardiac Magnetic Resonance.

    Directory of Open Access Journals (Sweden)

    Jiwon Kim

    Full Text Available Non-ischemic fibrosis (NIF on cardiac magnetic resonance (CMR has been linked to poor prognosis, but its association with adverse right ventricular (RV remodeling is unknown. This study examined a broad cohort of patients with RV dysfunction, so as to identify relationships between NIF and RV remodeling indices, including RV pressure load, volume and wall stress.The population comprised patients with RV dysfunction (EF 6-fold more common in the highest, vs. the lowest, common tertile of PASP and RV size (p<0.001.Among wall stress components, NIF was independently associated with RV chamber dilation and afterload, supporting the concept that NIF is linked to adverse RV chamber remodeling.

  2. Functional and geometrical interference and interdependency between the right and left ventricle in cor pulmonale: an experimental study on simultaneous measurement of biventricular geometry of acute right ventricular pressure overload.

    Science.gov (United States)

    Yamashita, H; Onodera, S; Imamoto, T; Obara, A; Tanazawa, S; Takashio, T; Morimoto, H; Inoue, H

    1989-10-01

    To clarify the effects of right ventricular (RV) pressure overload on functional and geometrical interference and interdependency between the right and left ventricle, both ventricular internal diameters were measured by the microcrystal technique during lycopodium induced pulmonary embolization in the dog. By repeated embolization, RV systolic pressure was increased progressively until it reached a peak value of about 60-70 mmHg, then it began to fall. At the same time, the hemodynamics deteriorated progressively resulting in death. During the experiment, gradual leftward displacement of the interventricular septum (IVS) without any change in left ventricular (LV) free wall geometry was observed. In pulmonary embolic shock, which showed a fall in LV pressure to about 60 mmHg and cardiac output to about 40% of control, the leftward displacement of IVS became marked, and the cooperative movement of IVS to LV contraction disappeared. The IVS position during acute RV pressure overload was able to account for the transseptal pressure gradient. The importance of IVS position and motion in cardiac function during acute RV pressure overload was stressed. Furthermore, to establish the theoretical treatment in acute cardiopulmonary resuscitation, ligation of the descending aorta (AoL) or norepinephrine ("N") or isoproterenol ("I") administration were examined in a canine pulmonary embolic shock model. AoL or "N" improved the deteriorated hemodynamics with restoration of biventricular geometry. However, "I" did not restore the biventricular geometry despite the transiently improved hemodynamics, and the experimental animals were unable to survive. These results suggest the importance of the maintainance of systemic pressure for the restoration of failed RV function. Further integrated studies are required to understand biventricular interference and interdependency.

  3. Postnatal ablation of Foxm1 from cardiomyocytes causes late onset cardiac hypertrophy and fibrosis without exacerbating pressure overload-induced cardiac remodeling.

    Directory of Open Access Journals (Sweden)

    Craig Bolte

    Full Text Available Heart disease remains a leading cause of morbidity and mortality in the industrialized world. Hypertrophic cardiomyopathy is the most common genetic cardiovascular disorder and the most common cause of sudden cardiac death. Foxm1 transcription factor (also known as HFH-11B, Trident, Win or MPP2 plays an important role in the pathogenesis of various cancers and is a critical mediator of post-injury repair in multiple organs. Foxm1 has been previously shown to be essential for heart development and proliferation of embryonic cardiomyocytes. However, the role of Foxm1 in postnatal heart development and in cardiac injury has not been evaluated. To delete Foxm1 in postnatal cardiomyocytes, αMHC-Cre/Foxm1(fl/fl mice were generated. Surprisingly, αMHC-Cre/Foxm1(fl/fl mice exhibited normal cardiomyocyte proliferation at postnatal day seven and had no defects in cardiac structure or function but developed cardiac hypertrophy and fibrosis late in life. The development of cardiomyocyte hypertrophy and cardiac fibrosis in aged Foxm1-deficient mice was associated with reduced expression of Hey2, an important regulator of cardiac homeostasis, and increased expression of genes critical for cardiac remodeling, including MMP9, αSMA, fibronectin and vimentin. We also found that following aortic constriction Foxm1 mRNA and protein were induced in cardiomyocytes. However, Foxm1 deletion did not exacerbate cardiac hypertrophy or fibrosis following chronic pressure overload. Our results demonstrate that Foxm1 regulates genes critical for age-induced cardiomyocyte hypertrophy and cardiac fibrosis.

  4. The effect of single overloading on stress corrosion cracking

    International Nuclear Information System (INIS)

    Ito, Yuzuru; Saito, Masahiro

    2008-01-01

    In the normal course of nuclear power plant operation in Japan, proof testing has been performed after periodic plant inspections. In this proof test procedure, the reactor pressure vessel and pipes of the primary coolant loop are subjected to a specified overload with a slightly higher hydraulic pressure than during normal operation. This specified overload is so called a single overload' in material testing. It is well known that the fatigue crack growth rate is decreased after a single overload has been applied to the specimen. However, it is not clear whether the stress corrosion cracking rate is also decreased after a single overload. In this study, the effect of a single overload on the stress corrosion cracking rate under simulated boiling water reactor environment was evaluated by examining a singly overloaded WOL (wedge opening load) specimen. The WOL specimen for the stress corrosion cracking test was machined from sensitized 304 type austenitic stainless steel. Since the crack extension length was 3.2% longer in the case of a more severely overloaded specimen, it was observed than the stress corrosion cracking rate is also decreased after the single overload has been applied to the specimen. (author)

  5. Influence of Hydraulic Design on Stability and on Pressure Pulsations in Francis Turbines at Overload, Part Load and Deep Part Load based on Numerical Simulations and Experimental Model Test Results

    International Nuclear Information System (INIS)

    Magnoli, M V; Maiwald, M

    2014-01-01

    Francis turbines have been running more and more frequently in part load conditions, in order to satisfy the new market requirements for more dynamic and flexible energy generation, ancillary services and grid regulation. The turbines should be able to be operated for longer durations with flows below the optimum point, going from part load to deep part load and even speed-no-load. These operating conditions are characterised by important unsteady flow phenomena taking place at the draft tube cone and in the runner channels, in the respective cases of part load and deep part load. The current expectations are that new Francis turbines present appropriate hydraulic stability and moderate pressure pulsations at overload, part load, deep part load and speed-no-load with high efficiency levels at normal operating range. This study presents series of investigations performed by Voith Hydro with the objective to improve the hydraulic stability of Francis turbines at overload, part load and deep part load, reduce pressure pulsations and enlarge the know-how about the transient fluid flow through the turbine at these challenging conditions. Model test measurements showed that distinct runner designs were able to influence the pressure pulsation level in the machine. Extensive experimental investigations focused on the runner deflector geometry, on runner features and how they could reduce the pressure oscillation level. The impact of design variants and machine configurations on the vortex rope at the draft tube cone at overload and part load and on the runner channel vortex at deep part load were experimentally observed and evaluated based on the measured pressure pulsation amplitudes. Numerical investigations were employed for improving the understanding of such dynamic fluid flow effects. As example for the design and experimental investigations, model test observations and pressure pulsation curves for Francis machines in mid specific speed range, around n qopt = 50

  6. Associations of maximal voluntary isometric hip extension torque with muscle size of hamstring and gluteus maximus and intra-abdominal pressure.

    Science.gov (United States)

    Tayashiki, Kota; Hirata, Kosuke; Ishida, Kiraku; Kanehisa, Hiroaki; Miyamoto, Naokazu

    2017-06-01

    Muscle size of the hamstring and gluteus maximus (GM) as well as intra-abdominal pressure (IAP) are considered as factors affecting the torque development during hip extension. This study examined the associations of torque development during maximal voluntary isometric hip extension with IAP and muscle size of the hamstring and GM. Anatomical cross-sectional area (ACSA) of the hamstring and thickness of GM were determined in 20 healthy young males using an ultrasonography apparatus (Experiment 1). Torque and IAP were simultaneously measured while subjects performed maximal voluntary isometric hip extension. The IAP was measured using a pressure transducer placed in the rectum and determined at the time at which the developed torque reached to the maximal. In Experiment 2, torque and IAP were measured during maximal voluntary isometric hip flexion in 18 healthy young males. The maximal hip extension torque was significantly correlated with the IAP (r = 0.504, P = 0.024), not with the ACSA of the hamstring (r = 0.307, P = 0.188) or the thickness of GM (r = 0.405, P = 0.076). The relationship was still significant even when the ACSA of the hamstring and the thickness of GM were adjusted statistically (r = 0.486, P = 0.041). The maximal hip flexion torque was not significantly correlated with the IAP (r = -0.118, P = 0.642). The current results suggest that IAP can contribute independently of the muscle size of the agonists to maximal voluntary hip extension torque.

  7. In vivo measurements of maximal occlusal force and minimal pressure threshold on overdentures supported by implants or natural roots: a comparative study, Part 1.

    Science.gov (United States)

    Mericske-Stern, R; Hofmann, J; Wedig, A; Geering, A H

    1993-01-01

    Numerous investigations give evidence of improvement of masticatory performance when edentulous patients have had implants placed. A comparative study was carried out to investigate the oral function and tactile sensibility of patients restored with implant-supported overdentures. Twenty-six patients with ITI implants and 18 patients with natural-tooth roots were selected. The minimal pressure threshold perceived in vertical and horizontal directions was registered with dynamometers. Maximal occlusal force was recorded with a miniature bite recorder placed between each pair of antagonistic teeth on both jaw sides separately. All measurements were repeated three times and the average was calculated. The records of minimal perceived pressure revealed a significantly higher threshold (factor 100) for the implant group. In both test groups, values registered in the vertical direction were slightly increased. A tendency for test subjects with implants to reach higher maximal occlusal force was observed, but not at a statistically significant level. In both test groups, the average maximum was found on the second premolar. The minimal pressure threshold seems to depend on the presence of receptors in the periodontal ligament. The records of maximal occlusal force, which were similar in both test groups, lead to the assumption that the limitation in maximal occlusal capacity of overdenture wearers is multifactorial and does not depend on the presence of a periodontal ligament.

  8. Relationship between loss in parenchymal elastic recoil pressure and maximal airway narrowing in subjects with alpha1-antitrypsin deficiency

    NARCIS (Netherlands)

    Cheung, D.; Schot, R.; Zwinderman, A. H.; Zagers, H.; Dijkman, J. H.; Sterk, P. J.

    1997-01-01

    Airway hyperresponsiveness is characterized by an increase in sensitivity and excessive airway narrowing to inhaled bronchoconstrictor stimuli. There is experimental evidence that maximal airway narrowing is related to lung elasticity in normal and asthmatic subjects. We hypothesized that reduced

  9. Hemodynamic mechanisms of the attenuated blood pressure response to mental stress after a single bout of maximal dynamic exercise in healthy subjects

    Directory of Open Access Journals (Sweden)

    F.J. Neves

    2012-07-01

    Full Text Available To determine the hemodynamic mechanisms responsible for the attenuated blood pressure response to mental stress after exercise, 26 healthy sedentary individuals (age 29 ± 8 years underwent the Stroop color-word test before and 60 min after a bout of maximal dynamic exercise on a treadmill. A subgroup (N = 11 underwent a time-control experiment without exercise. Blood pressure was continuously and noninvasively recorded by infrared finger photoplethysmography. Stroke volume was derived from pressure signals, and cardiac output and peripheral vascular resistance were calculated. Perceived mental stress scores were comparable between mental stress tests both in the exercise (P = 0.96 and control (P = 0.24 experiments. After exercise, the blood pressure response to mental stress was attenuated (pre: 10 ± 13 vs post: 6 ± 7 mmHg; P 0.05. In conclusion, a single bout of maximal dynamic exercise attenuates the blood pressure response to mental stress in healthy subjects, along with lower stroke volume and cardiac output, denoting an acute modulatory action of exercise on the central hemodynamic response to mental stress.

  10. Overload road damage model

    CSIR Research Space (South Africa)

    Roux, MP

    2005-03-01

    Full Text Available Not only do overloaded vehicles pose an increased safety risk on the road (reduced stability and braking efficiency etc.), but they also accelerate the rate of deterioration of the road network and increase road maintenance costs, which in turn...

  11. Diabetic db/db mice do not develop heart failure upon pressure overload: a longitudinal in vivo PET, MRI, and MRS study on cardiac metabolic, structural, and functional adaptations.

    Science.gov (United States)

    Abdurrachim, Desiree; Nabben, Miranda; Hoerr, Verena; Kuhlmann, Michael T; Bovenkamp, Philipp; Ciapaite, Jolita; Geraets, Ilvy M E; Coumans, Will; Luiken, Joost J F P; Glatz, Jan F C; Schäfers, Michael; Nicolay, Klaas; Faber, Cornelius; Hermann, Sven; Prompers, Jeanine J

    2017-08-01

    Heart failure is associated with altered myocardial substrate metabolism and impaired cardiac energetics. Comorbidities like diabetes may influence the metabolic adaptations during heart failure development. We quantified to what extent changes in substrate preference, lipid accumulation, and energy status predict the longitudinal development of hypertrophy and failure in the non-diabetic and the diabetic heart. Transverse aortic constriction (TAC) was performed in non-diabetic (db/+) and diabetic (db/db) mice to induce pressure overload. Magnetic resonance imaging, 31P magnetic resonance spectroscopy (MRS), 1H MRS, and 18F-fluorodeoxyglucose-positron emission tomography (PET) were applied to measure cardiac function, energy status, lipid content, and glucose uptake, respectively. In vivo measurements were complemented with ex vivo techniques of high-resolution respirometry, proteomics, and western blotting to elucidate the underlying molecular pathways. In non-diabetic mice, TAC induced progressive cardiac hypertrophy and dysfunction, which correlated with increased protein kinase D-1 (PKD1) phosphorylation and increased glucose uptake. These changes in glucose utilization preceded a reduction in cardiac energy status. At baseline, compared with non-diabetic mice, diabetic mice showed normal cardiac function, higher lipid content and mitochondrial capacity for fatty acid oxidation, and lower PKD1 phosphorylation, glucose uptake, and energetics. Interestingly, TAC affected cardiac function only mildly in diabetic mice, which was accompanied by normalization of phosphorylated PKD1, glucose uptake, and cardiac energy status. The cardiac metabolic adaptations in diabetic mice seem to prevent the heart from failing upon pressure overload, suggesting that restoring the balance between glucose and fatty acid utilization is beneficial for cardiac function. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions

  12. Automatic determination of pressurized water reactor core loading patterns which maximize end-of-cycle reactivity within power peaking and burnup constraints

    International Nuclear Information System (INIS)

    Hobson, G.H.

    1985-01-01

    An automated procedure for determining the optimal core loading pattern for a pressurized water reactor which maximizes end-of-cycle k/sub eff/ while satisfying constraints on power peaking and discharge burnup has been developed. The optimization algorithm combines a two energy group, two-dimensional coarse-mesh finite difference diffusion theory neutronics model to simulate core conditions, a perturbation theory approach to determine reactivity, flux, power and burnup changes as a function of assembly shuffling, and Monte Carlo integer programming to select the optimal loading pattern solution. The core examined was a typical Cycle 2 reload with no burnable poisons. Results indicate that the core loading pattern that maximizes end-of-cycle k/sub eff/ results in a 5.4% decrease in fuel cycle costs compared with the core loading pattern that minimizes the maximum relative radial power peak

  13. A comparison of maximal inspiratory pressure and forced vital capacity as potential criteria for initiating non-invasive ventilation in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Mendoza, Michelle; Gelinas, Deborah F; Moore, Dan H; Miller, Robert G

    2007-04-01

    Using a retrospective analysis of 161 patients with amyotrophic lateral sclerosis (ALS) from the Western ALS study group (WALS) database, the sensitivity of maximal inspiratory pressure (MIP)NIV) were compared. Sixty-five per cent of patients at enrollment met the MIP criterion, compared with only 8% of patients who met the FVC criterion. There were no cases in which FVCNIV, a MIP< -60 cm H(2)O allows US clinicians to obtain non-invasive ventilatory support for patients earlier than if using the FVC criterion alone.

  14. Automatic determination of pressurized water reactor core loading patterns that maximize beginning-of-cycle reactivity within power-peaking and burnup constraints

    International Nuclear Information System (INIS)

    Hobson, G.H.; Turinsky, P.J.

    1986-01-01

    Computational capability has been developed to automatically determine a good estimate of the core loading pattern, which minimizes fuel cycle costs for a pressurized water reactor (PWR). Equating fuel cycle cost minimization with core reactivity maximization, the objective is to determine the loading pattern that maximizes core reactivity while satisfying power peaking, discharge burnup, and other constraints. The method utilizes a two-dimensional, coarse-mesh, finite difference scheme to evaluate core reactivity and fluxes for an initial reference loading pattern. First-order perturbation theory is applied to determine the effects of assembly shuffling on reactivity, power distribution, end-of-cycle burnup. Monte Carlo integer programming is then used to determine a near-optimal loading pattern within a range of loading patterns near the reference pattern. The process then repeats with the new loading pattern as the reference loading pattern and terminates when no better loading pattern can be determined. The process was applied with both reactivity maximization and radial power-peaking minimization as objectives. Results on a typical large PWR indicate that the cost of obtaining an 8% improvement in radial power-peaking margin is ≅2% in fuel cycle costs, for the reload core loaded without burnable poisons that was studied

  15. Entropy maximization

    Indian Academy of Sciences (India)

    Abstract. It is shown that (i) every probability density is the unique maximizer of relative entropy in an appropriate class and (ii) in the class of all pdf f that satisfy. ∫ fhi dμ = λi for i = 1, 2,...,...k the maximizer of entropy is an f0 that is pro- portional to exp(. ∑ ci hi ) for some choice of ci . An extension of this to a continuum of.

  16. Entropy Maximization

    Indian Academy of Sciences (India)

    It is shown that (i) every probability density is the unique maximizer of relative entropy in an appropriate class and (ii) in the class of all pdf that satisfy ∫ f h i d = i for i = 1 , 2 , … , … k the maximizer of entropy is an f 0 that is proportional to exp ⁡ ( ∑ c i h i ) for some choice of c i . An extension of this to a continuum of ...

  17. Inhibition of PKC-dependent extracellular Ca{sup 2+} entry contributes to the depression of contractile activity in long-term pressure-overloaded endothelium-denuded rat aortas

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, J.; López, R.M.; López, P.; Castillo, M.C.; Querejeta, E.; Ruiz, A.; Castillo, E.F. [Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, México, DF (Mexico)

    2014-08-01

    We examined the contractile responsiveness of rat thoracic aortas under pressure overload after long-term suprarenal abdominal aortic coarctation (lt-Srac). Endothelium-dependent angiotensin II (ANG II) type 2 receptor (AT{sub 2}R)-mediated depression of contractions to ANG II has been reported in short-term (1 week) pressure-overloaded rat aortas. Contractility was evaluated in the aortic rings of rats subjected to lt-Srac or sham surgery (Sham) for 8 weeks. ANG I and II levels and AT{sub 2}R protein expression in the aortas of lt-Srac and Sham rats were also evaluated. lt-Srac attenuated the contractions of ANG II and phenylephrine in the aortas in an endothelium-independent manner. However, lt-Srac did not influence the transient contractions induced in endothelium-denuded aortic rings by ANG II, phenylephrine, or caffeine in Ca{sup 2+}-free medium or the subsequent tonic constrictions induced by the addition of Ca{sup 2+} in the absence of agonists. Thus, the contractions induced by Ca{sup 2+} release from intracellular stores and Ca{sup 2+} influx through stored-operated channels were not inhibited in the aortas of lt-Srac rats. Potassium-elicited contractions in endothelium-denuded aortic rings of lt-Srac rats remained unaltered compared with control tissues. Consequently, the contractile depression observed in aortic tissues of lt-Srac rats cannot be explained by direct inhibition of voltage-operated Ca{sup 2+} channels. Interestingly, 12-O-tetradecanoylphorbol-13-acetate-induced contractions in endothelium-denuded aortic rings of lt-Srac rats were depressed in the presence but not in the absence of extracellular Ca{sup 2+}. Neither levels of angiotensins nor of AT{sub 2}R were modified in the aortas after lt-Srac. The results suggest that, in rat thoracic aortas, lt-Srac selectively inhibited protein kinase C-mediated activation of contraction that is dependent on extracellular Ca{sup 2+} entry.

  18. [Role of melatonin in calcium overload-induced heart injury].

    Science.gov (United States)

    Kong, Lingheng; Wei, Ming; Sun, Na; Zhu, Juanxia; Su, Xingli

    2017-06-28

    To investigate the role of melatonin in calcium overload-induced heart injury.
 Methods: Thirty-two rats were divided into 4 groups: a control group (Control), a melatonin control group (Mel), a calcium overload group (CaP), and a calcium overload plus melatonin group (Mel+CaP). Isolated Sprague Dawley male rat hearts underwent Langendorff perfusion. Left ventricular developed pressure (LVDP) was calculated to evaluate the myocardial performance. Triphenyltetrazolium chloride staining was used to measure the infarct size of myocardium. Lactate dehydrogenase (LDH) activity in the coronary flow was determined. The expressions of caspase-3 and cytochrome c were determined by Western blot. The pathological morphological changes in myocardial fiber were analyzed by HE staining.
 Results: Compared with the control group, calcium overload significantly induced an enlarged infarct size (Poverload-induced heart injury.

  19. Fluid overload in the ICU: evaluation and management.

    Science.gov (United States)

    Claure-Del Granado, Rolando; Mehta, Ravindra L

    2016-08-02

    Fluid overload is frequently found in acute kidney injury patients in critical care units. Recent studies have shown the relationship of fluid overload with adverse outcomes; hence, manage and optimization of fluid balance becomes a central component of the management of critically ill patients. In critically ill patients, in order to restore cardiac output, systemic blood pressure and renal perfusion an adequate fluid resuscitation is essential. Achieving an appropriate level of volume management requires knowledge of the underlying pathophysiology, evaluation of volume status, and selection of appropriate solution for volume repletion, and maintenance and modulation of the tissue perfusion. Numerous recent studies have established a correlation between fluid overload and mortality in critically ill patients. Fluid overload recognition and assessment requires an accurate documentation of intakes and outputs; yet, there is a wide difference in how it is evaluated, reviewed and utilized. Accurate volume status evaluation is essential for appropriate therapy since errors of volume evaluation can result in either in lack of essential treatment or unnecessary fluid administration, and both scenarios are associated with increased mortality. There are several methods to evaluate fluid status; however, most of the tests currently used are fairly inaccurate. Diuretics, especially loop diuretics, remain a valid therapeutic alternative. Fluid overload refractory to medical therapy requires the application of extracorporeal therapies. In critically ill patients, fluid overload is related to increased mortality and also lead to several complications like pulmonary edema, cardiac failure, delayed wound healing, tissue breakdown, and impaired bowel function. Therefore, the evaluation of volume status is crucial in the early management of critically ill patients. Diuretics are frequently used as an initial therapy; however, due to their limited effectiveness the use of continuous

  20. Information Overload and Viral Marketing: Countermeasures and Strategies

    Science.gov (United States)

    Cheng, Jiesi; Sun, Aaron; Zeng, Daniel

    Studying information diffusion through social networks has become an active research topic with important implications in viral marketing applications. One of the fundamental algorithmic problems related to viral marketing is the Influence Maximization (IM) problem: given an social network, which set of nodes should be considered by the viral marketer as the initial targets, in order to maximize the influence of the advertising message. In this work, we study the IM problem in an information-overloaded online social network. Information overload occurs when individuals receive more information than they can process, which can cause negative impacts on the overall marketing effectiveness. Many practical countermeasures have been proposed for alleviating the load of information on recipients. However, how these approaches can benefit viral marketers is not well understood. In our work, we have adapted the classic Information Cascade Model to incorporate information overload and study its countermeasures. Our results suggest that effective control of information overload has the potential to improve marketing effectiveness, but the targeting strategy should be re-designed in response to these countermeasures.

  1. Determination of optimized oxygen partial pressure to maximize the liver regenerative potential of the secretome obtained from adipose-derived stem cells.

    Science.gov (United States)

    Lee, Sang Chul; Kim, Kee-Hwan; Kim, Ok-Hee; Lee, Sang Kuon; Hong, Ha-Eun; Won, Seong Su; Jeon, Sang-Jin; Choi, Byung Jo; Jeong, Wonjun; Kim, Say-June

    2017-08-03

    A hypoxic-preconditioned secretome from stem cells reportedly promotes the functional and regenerative capacity of the liver more effectively than a control secretome. However, the optimum oxygen partial pressure (pO 2 ) in the cell culture system that maximizes the therapeutic potential of the secretome has not yet been determined. We first determined the cellular alterations in adipose tissue-derived stem cells (ASCs) cultured under different pO 2 (21%, 10%, 5%, and 1%). Subsequently, partially hepatectomized mice were injected with the secretome of ASCs cultured under different pO 2 , and then sera and liver specimens were obtained for analyses. Of all AML12 cells cultured under different pO 2 , the AML12 cells cultured under 1% pO 2 showed the highest mRNA expression of proliferation-associated markers (IL-6, HGF, and VEGF). In the cell proliferation assay, the AML12 cells cultured with the secretome of 1% pO 2 showed the highest cell proliferation, followed by the cells cultured with the secretome of 21%, 10%, and 5% pO 2 , in that order. When injected into the partially hepatectomized mice, the 1% pO 2 secretome most significantly increased the number of Ki67-positive cells, reduced serum levels of proinflammatory mediators (IL-6 and TNF-α), and reduced serum levels of liver transaminases. In addition, analysis of the liver specimens indicated that injection with the 1% pO 2 secretome maximized the expression of the intermediate molecules of the PIP3/Akt and IL-6/STAT3 signaling pathways, all of which are known to promote liver regeneration. The data of this study suggest that the secretome of ASCs cultured under 1% pO 2 has the highest liver reparative and regenerative potential of all the secretomes tested here.

  2. The overloaded right heart and ventricular interdependence.

    Science.gov (United States)

    Naeije, Robert; Badagliacca, Roberto

    2017-10-01

    The right and the left ventricle are interdependent as both structures are nested within the pericardium, have the septum in common and are encircled with common myocardial fibres. Therefore, right ventricular volume or pressure overloading affects left ventricular function, and this in turn may affect the right ventricle. In normal subjects at rest, right ventricular function has negligible interaction with left ventricular function. However, the right ventricle contributes significantly to the normal cardiac output response to exercise. In patients with right ventricular volume overload without pulmonary hypertension, left ventricular diastolic compliance is decreased and ejection fraction depressed but without intrinsic alteration in contractility. In patients with right ventricular pressure overload, left ventricular compliance is decreased with initial preservation of left ventricular ejection fraction, but with eventual left ventricular atrophic remodelling and altered systolic function. Breathing affects ventricular interdependence, in healthy subjects during exercise and in patients with lung diseases and altered respiratory system mechanics. Inspiration increases right ventricular volumes and decreases left ventricular volumes. Expiration decreases both right and left ventricular volumes. The presence of an intact pericardium enhances ventricular diastolic interdependence but has negligible effect on ventricular systolic interdependence. On the other hand, systolic interdependence is enhanced by a stiff right ventricular free wall, and decreased by a stiff septum. Recent imaging studies have shown that both diastolic and systolic ventricular interactions are negatively affected by right ventricular regional inhomogeneity and prolongation of contraction, which occur along with an increase in pulmonary artery pressure. The clinical relevance of these observations is being explored. Published on behalf of the European Society of Cardiology. All rights

  3. Clinical studies on myocardial perfusion imaging in patients with right ventricular overload

    International Nuclear Information System (INIS)

    Abo, Kenji; Yamagata, Takashi; Nakajima, Masao; Fujita, Kimiaki; Morita, Nobuo

    1979-01-01

    Patients with heart disease which had been clinically diagnosed underwent 201 Tl myocardial perfusion imaging. The thickness of right ventricular wall measured from original images was directly proportional to systolic pressure of the right ventricle measured by cardiac catheterization, and 201 Tl activity in the right ventricle was more directly proportional to systolic pressure of the right ventricle. Imaging patterns of various diseases were also described. Images of patients with hypertrophic cardiomyopathy revealed that right ventricular wall was thin and right ventricular cavity was small, but the thickness of septal wall and left ventricular wall were maximal. Images of patients with mitral insufficiency revealed that the thickness of right ventricular wall, septal wall, and left ventricular wall was medium, and the right ventricular cavity was smaller than the left ventricular cavity. Images of patients with congestive cardiomyopathy and congestive cardiac failure showed that enlargement of both ventricular cavities was disproportionate to the thickness of each wall. Images of patients with arterial septal defect revealed that the thickness of each wall was comparatively normal, the right ventricular cavity was maximal, and the left ventricular cavity was minimal. Images of patients with primary pulmonary hypertention, pulmonary stenosis and tetralogy of Fallot in whom pressure overload was recognized revealed severe thickenings of right ventricular wall, moderate enlargement of the right ventricle, small left ventricle, and thin left ventricular wall. (Tsunoda, M.)

  4. Sensory overload: A concept analysis.

    Science.gov (United States)

    Scheydt, Stefan; Müller Staub, Maria; Frauenfelder, Fritz; Nielsen, Gunnar H; Behrens, Johann; Needham, Ian

    2017-04-01

    In the context of mental disorders sensory overload is a widely described phenomenon used in conjunction with psychiatric interventions such as removal from stimuli. However, the theoretical foundation of sensory overload as addressed in the literature can be described as insufficient and fragmentary. To date, the concept of sensory overload has not yet been sufficiently specified or analyzed. The aim of the study was to analyze the concept of sensory overload in mental health care. A literature search was undertaken using specific electronic databases, specific journals and websites, hand searches, specific library catalogues, and electronic publishing databases. Walker and Avant's method of concept analysis was used to analyze the sources included in the analysis. All aspects of the method of Walker and Avant were covered in this concept analysis. The conceptual understanding has become more focused, the defining attributes, influencing factors and consequences are described and empirical referents identified. The concept analysis is a first step in the development of a middle-range descriptive theory of sensory overload based on social scientific and stress-theoretical approaches. This specification may serve as a fundament for further research, for the development of a nursing diagnosis or for guidelines. © 2017 Australian College of Mental Health Nurses Inc.

  5. Thallium-201 myocardial imaging for evaluation of right-ventricular overloading

    International Nuclear Information System (INIS)

    Kondo, M.; Kubo, A.; Yamazaki, H.; Ohsuzu, F.; Handa, S.; Tsugu, T.; Masaki, H.; Kinoshita, F.; Hashimoto, S.

    1978-01-01

    This study evaluated the specificity and sensitivity of Tl-201 myocardial imaging in the detection of right-ventricular (RV) overloading. Right-ventricular visualization (RVV) after administration of Tl-201 chloride was studied on 99 patients with various heart diseases. Tracer uptake in the free wall of the RV was graded in four degrees. The degree of RVV was compared with the findings of cardiac catheterization. The comparisons indicated that the uptake increased in step with the inreases in RV systolic pressure, RV end-diastolic pressure, mean pulmonary arterial pressure, total pulmonary vascular resistance, and stroke-work index of the right ventricle (P < 0.05--P < 0.001). Of the patients with visible RV, all but three had RV overloading, and all but three of those without RVV had normal RV systolic pressure. Myocardial images also reflect the type of RV overloading. In patients with RV pressure overloading, the septum showed a tendency to appear straight. In patients with atrial septal defect leading to RV volume overloading, the RV cavity was dilated, the LV image small, and the septum convex toward the RV cavity. These results indicate that Tl-201 myocardial imaging is a sensitive and specific method for the study of RV overloading

  6. Magnetic resonance imaging of splenic iron overload

    International Nuclear Information System (INIS)

    Arrive, L.; Thurnher, S.; Hricak, H.; Price, D.C.

    1990-01-01

    The value of magnetic resonance (MR) imaging in assessing iron overload in the spleen was retrospectively investigated in 40 consecutive patients. MR appearance, mesaure of signal intensity and T1-and T2-relaxation times were correlated with the histologically determined level of iron in the spleen in each patient. Histologic examination revealed no iron overload in 19 patients, mild iron overload in seven, moderate iron overload in six, and severe iron overload in eight. All 19 patients with no splenic iron overload and 11 of the other 21 patients with splenic iron overload were correctly identified by MR imaging (sensitivity 52%, specificity 100%, accuracy 75%). Splenic iron overload was diagnosed when a decrease of signal intensity of the spleen compared with those of adipose tissue and renal cortex was demonstrated. MR images demonstrated all eight cases of severe, three of the six cases of moderate, and none of the seven cases of mild iron overload. Only spleens with severe iron overload had a significant mean decrease in signal intensity and T1- and T2-relaxation times. Although specific, MR imaging is poorly sensitive to splenic iron overload. (author). 15 refs.; 5 figs.; 3 tabs

  7. Elbow arthroscopy: valgus extension overload.

    Science.gov (United States)

    Ahmad, Christopher S; Conway, John E

    2011-01-01

    Valgus torque combined with deceleration produces high compression and shear forces acting on the posteromedial olecranon and the posteromedial trochlea. This valgus extension overload process may cause posteromedial trochlea chondromalacia, chondral flap formation, osteochondrosis, subchondral erosion, a subchondral insufficiency fracture, and marginal exostosis formation. Olecranon pathologies include proximal stress reaction, a posteromedial tip stress fracture, a transverse proximal process stress fracture, exostosis formation, exostosis fragmentation, and intra-articular loose bodies. Symptoms include posteromedial elbow pain during the deceleration phase of the throwing motion. The extension impingement test reproduces posterior or posteromedial pain similar to that experienced while throwing. Special radiographic techniques and CT scans can show loose bodies and osteophyte fragmentation. Surgical treatment is indicated when symptoms persist despite nonsurgical management. Based on clinical and basic science research, all patients with valgus extension overload should be comprehensively evaluated for medial ulnar collateral ligament insufficiency. Surgical treatment is limited to the resection of osteophytes only; normal olecranon should not be resected.

  8. Females Are Protected From Iron-Overload Cardiomyopathy Independent of Iron Metabolism: Key Role of Oxidative Stress.

    Science.gov (United States)

    Das, Subhash K; Patel, Vaibhav B; Basu, Ratnadeep; Wang, Wang; DesAulniers, Jessica; Kassiri, Zamaneh; Oudit, Gavin Y

    2017-01-23

    Sex-related differences in cardiac function and iron metabolism exist in humans and experimental animals. Male patients and preclinical animal models are more susceptible to cardiomyopathies and heart failure. However, whether similar differences are seen in iron-overload cardiomyopathy is poorly understood. Male and female wild-type and hemojuvelin-null mice were injected and fed with a high-iron diet, respectively, to develop secondary iron overload and genetic hemochromatosis. Female mice were completely protected from iron-overload cardiomyopathy, whereas iron overload resulted in marked diastolic dysfunction in male iron-overloaded mice based on echocardiographic and invasive pressure-volume analyses. Female mice demonstrated a marked suppression of iron-mediated oxidative stress and a lack of myocardial fibrosis despite an equivalent degree of myocardial iron deposition. Ovariectomized female mice with iron overload exhibited essential pathophysiological features of iron-overload cardiomyopathy showing distinct diastolic and systolic dysfunction, severe myocardial fibrosis, increased myocardial oxidative stress, and increased expression of cardiac disease markers. Ovariectomy prevented iron-induced upregulation of ferritin, decreased myocardial SERCA2a levels, and increased NCX1 levels. 17β-Estradiol therapy rescued the iron-overload cardiomyopathy in male wild-type mice. The responses in wild-type and hemojuvelin-null female mice were remarkably similar, highlighting a conserved mechanism of sex-dependent protection from iron-overload-mediated cardiac injury. Male and female mice respond differently to iron-overload-mediated effects on heart structure and function, and females are markedly protected from iron-overload cardiomyopathy. Ovariectomy in female mice exacerbated iron-induced myocardial injury and precipitated severe cardiac dysfunction during iron-overload conditions, whereas 17β-estradiol therapy was protective in male iron-overloaded mice.

  9. Left ventricular function in right ventricular overload

    International Nuclear Information System (INIS)

    Iwanaga, Shiro; Handa, Shunnosuke; Abe, Sumihisa; Onishi, Shohei; Nakamura, Yoshiro; Kunieda, Etsuo; Ogawa, Koichi; Kubo, Atsushi

    1989-01-01

    This study clarified regional and global functions of the distorted left ventricle due to right ventricular overload by gated radionuclide ventriculography (RNV). Cardiac catheterization and RNV were performed in 13 cases of atrial septal defect (ASD), 13 of pure mitral stenosis (MS), 10 of primary pulmonary hypertension (PPH), and 10 of normal subjects (NL). Right ventricular systolic pressure (RVSP) was 32.9±13.9, 45.0±12.2, 88.3±17.1, and 21.2±4.5 mmHg, respectively. The end-systolic LAO view of the left ventricle was halved into septal and free-wall sides. The end-diastolic halves were determined in the same plane. Ejection fractions of the global left ventricle (LVEF), global right ventricle (RVEF), the septal half of the left ventricle (SEPEF), and the free-wall half of the left ventricle (FWEF) were obtained. LVEF was 56.8±9.8% in NL, 52.8±10.5% in ASD, and 49.5±12.9% in PPH. In MS, LVEF (47.0±13.0%) was smaller than those in the other groups. RVEF was 37.0±5.2% in NL, 43.7±15.5% in ASD, and 32.8±11.5% in MS. In PPH, RVEF (25.0±10.6%) was smaller than those in the other groups. SEPEF was smaller in ASD (42.5±13.2%), MS (40.4±13.1%), PPH (40.5±12.5%) than in NL (53.5±8.5%). Systolic function of the septal half of the left ventricle was disturbed by right ventricular overload. RVEF (r=-0.35, p<0.05) and SEPEF (r=-0.51, p<0.01) had negative correlations with RVSP. As RVSP rose, systolic function of the septal half of the left ventricle was more severely disturbed. FWEF was the same among the four groups; NL (57.0±12.6%), ASD (48.6±15.2%), MS (50.5±12.0%), and PPH (51.1±12.3%). There was a good correlation between SEPEF and LVEF in NL (r=0.81), although in PPH this correlation was poor (r=0.64). These data showed that the distorted left ventricular due to right ventricular overload maintains its global function with preserved function of the free-wall side. (J.P.N.)

  10. Effects of a high-intensity interval training program versus a moderate-intensity continuous training program on maximal oxygen uptake and blood pressure in healthy adults: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Arboleda Serna, Víctor Hugo; Arango Vélez, Elkin Fernando; Gómez Arias, Rubén Darío; Feito, Yuri

    2016-08-18

    Participation in aerobic exercise generates increased cardiorespiratory fitness, which results in a protective factor for cardiovascular disease and all-cause mortality. High-intensity interval training might cause higher increases in cardiorespiratory fitness in comparison with moderate-intensity continuous training; nevertheless, current evidence is not conclusive. To our knowledge, this is the first study to test the effect of high-intensity interval training with total load duration of 7.5 min per session. A randomized controlled trial will be performed on two groups of healthy, sedentary male volunteers (n = 44). The study protocol will include 24 exercise sessions, three times a week, including aerobic training on a treadmill and strength training exercises. The intervention group will perform 15 bouts of 30 s, each at an intensity between 90 % and 95 % of maximal heart rate. The control group will complete 40 min of continuous exercise, ranging between 65 % and 75 % of maximal heart rate. The primary outcome measure to be evaluated will be maximal oxygen uptake (VO2max), and systolic and diastolic blood pressure will be evaluated as secondary outcome measures. Waist circumference, body mass index, and body composition will also be evaluated. Epidemiological evidence shows the link between VO2max and its association with chronic conditions that trigger CVD. Therefore, finding ways to improve VO2max and reduce blood pressure it is of vital importance to public health. NCT02288403 . Registered on 4 November 2014.

  11. Both cardiomyocyte and endothelial cell Nox4 mediate protection against hemodynamic overload-induced remodelling.

    Science.gov (United States)

    Zhang, Min; Mongue-Din, Heloise; Martin, Daniel; Catibog, Norman; Smyrnias, Ioannis; Zhang, Xiaohong; Yu, Bin; Wang, Minshu; Brandes, Ralf P; Schröder, Katrin; Shah, Ajay M

    2018-03-01

    NADPH oxidase-4 (Nox4) is an important reactive oxygen species (ROS) source that is upregulated in the haemodynamically overloaded heart. Our previous studies using global Nox4 knockout (Nox4KO) mice demonstrated a protective role of Nox4 during chronic abdominal aortic banding, involving a paracrine enhancement of myocardial capillary density. However, other authors who studied cardiac-specific Nox4KO mice reported detrimental effects of Nox4 in response to transverse aortic constriction (TAC). It has been speculated that these divergent results are due to cell-specific actions of Nox4 (i.e. cardiomyocyte Nox4 detrimental but endothelial Nox4 beneficial) and/or differences in the model of pressure overload (i.e. abdominal banding vs. TAC). This study aimed to (i) investigate whether the effects of Nox4 on pressure overload-induced cardiac remodelling vary according to the pressure overload model and (ii) compare the roles of cardiomyocyte vs. endothelial cell Nox4. Global Nox4KO mice subjected to TAC developed worse cardiac remodelling and contractile dysfunction than wild-type littermates, consistent with our previous results with abdominal aortic banding. Next, we generated inducible cardiomyocyte-specific Nox4 KO mice (Cardio-Nox4KO) and endothelial-specific Nox4 KO mice (Endo-Nox4KO) and studied their responses to pressure overload. Both Cardio-Nox4KO and Endo-Nox4KO developed worse pressure overload-induced cardiac remodelling and dysfunction than wild-type littermates, associated with significant decrease in protein levels of HIF1α and VEGF and impairment of myocardial capillarization. Cardiomyocyte as well as endothelial cell Nox4 contributes to protection against chronic hemodynamic overload-induced cardiac remodelling, at least in part through common effects on myocardial capillary density. © The Author 2017 Published by Oxford University Press on behalf of the European Society of Cardiology.

  12. Profit maximization mitigates competition

    DEFF Research Database (Denmark)

    Dierker, Egbert; Grodal, Birgit

    1996-01-01

    We consider oligopolistic markets in which the notion of shareholders' utility is well-defined and compare the Bertrand-Nash equilibria in case of utility maximization with those under the usual profit maximization hypothesis. Our main result states that profit maximization leads to less price...... competition than utility maximization. Since profit maximization tends to raise prices, it may be regarded as beneficial for the owners as a whole. Moreover, if profit maximization is a good proxy for utility maximization, then there is no need for a general equilibrium analysis that takes the distribution...... of profits among consumers fully into account and partial equilibrium analysis suffices...

  13. Fetal development and renal function in adult rats prenatally subjected to sodium overload.

    Science.gov (United States)

    Cardoso, Henriqueta D; Cabral, Edjair V; Vieira-Filho, Leucio D; Vieyra, Adalberto; Paixão, Ana D O

    2009-10-01

    The aims of this study were (1) to evaluate two factors that affect fetal development--placental oxidative stress (Ox) and plasma volume (PV)--in dams with sodium overload and (2) to correlate possible alterations in these factors with subsequent modifications in the renal function of adult offspring. Wistar dams were maintained on 0.17 M NaCl instead of water from 20 days before mating until either the twentieth pregnancy day/parturition or weaning. Colorimetric methods were used to measure Ox in maternal and offspring tissues, PV, 24-h urinary protein (U(Prot24 h)) and serum triacylglycerols (TG) and cholesterol (Chol). Renal hemodynamics was evaluated in the offspring at 90 days of age using a blood pressure transducer, a flow probe and inulin clearance to measure mean arterial pressure (MAP), renal blood flow and glomerular filtration rate (GFR), respectively. The number of nephrons (NN) was counted in kidney suspensions. Dams showed unchanged PV, placental Ox and fetal weight but increased U(Prot24 h) (150%, P sodium-overloaded pups showed increased U(Prot24 h) (45%, P sodium-overloaded rats showed increased U(Prot24 h) (27%, P sodium-overloaded group. We conclude that salt overload from the prenatal stage until weaning leads to alterations in lipid metabolism and in the renal function of the pups, which are additional to those alterations seen in rats only overloaded prenatally.

  14. Influences of overload on low cycle fatigue behaviors of elbow pipe with local wall thinning

    International Nuclear Information System (INIS)

    Sato, Kyohei; Ogino, Kanako; Takahashi, Koji; Ando, Kotoji; Urabe, Yoshio

    2011-01-01

    Low cycle fatigue tests were conducted using 100A elbow pipe specimens with or without local wall thinning. Local wall thinning was machined on the inside of the extrados of test elbows to simulate metal loss due to flow-accelerated corrosion or liquid droplet impingement erosion. Low cycle fatigue tests were carried out under displacement control with an inner pressure of 9 MPa. To simulate seismic events, low cycle fatigue tests were carried out on elbow pipe subjected to cyclic overloads. Regardless of local wall thinning, fatigue life of overload pipe was not so different from that of the non-overload pipe in appearance. Miner's rule can be applied to evaluate fatigue life of the elbow pipes with and without wall thinning, even if overload is applied. (author)

  15. Intelligent Overload Control for Composite Web Services

    NARCIS (Netherlands)

    Meulenhoff, P.J.; Ostendorf, D.R.; Zivkovic, Miroslav; Meeuwissen, H.B.; Gijsen, B.M.M.

    2009-01-01

    In this paper, we analyze overload control for composite web services in service oriented architectures by an orchestrating broker, and propose two practical access control rules which effectively mitigate the effects of severe overloads at some web services in the composite service. These two rules

  16. Polysynovitis after oligofructose overload in dairy cattle.

    Science.gov (United States)

    Danscher, A M; Enemark, H L; Andersen, P H; Aalbaek, B; Nielsen, O L

    2010-01-01

    Acute bovine laminitis is a systemic disease with local manifestations primarily affecting the claws. However, distension of the tarsocrural joints has been observed after experimental oligofructose overload in dairy heifers as a part of the complex interpreted as acute, clinical laminitis. Therefore, the aim of the present study was to study bovine synovial joints and tendon sheaths after oligofructose overload. Ten dairy heifers received oral oligofructose overload (17 g/kg body weight); four were killed 24h after overload and six after 72 h. Six control heifers received tap water and were killed after 72 or 96 h. Clinical examination included locomotion scoring and palpation of the tarsocrural joints. Ruminal fluid and blood was collected for measurements of pH and hydration status. Total protein concentrations and white blood cell (WBC) counts were determined in synovial fluid collected from tarsocrural joints after death. Synovial joints and tendon sheaths were examined and synovial membranes were studied microscopically. Swabs taken from the synovial cavities were subject to bacteriological culture. Heifers with oligofructose overload developed signs of ruminal and systemic acidosis. Lameness was observed in three of ten heifers 24h after overload and in all remaining heifers after 72 h. Distension of tarsocrural joints was observed from 18 h after overload and peaked at 30 h when all examined joints were moderately or severely distended. The synovial fluid was turbid and protein content and WBC counts were increased at both 24 and 72 h compared with controls. Bacterial culture was negative. Synovial membranes 24 and 72 h after overload had a fibrinous and neutrophil inflammatory reaction that regressed in severity between 24 and 72 h after overload. Heifers subjected to oligofructose overload therefore developed generalized sterile neutrophilic polysynovitis. Focus on this aspect of bovine laminitis may shed new light on the pathogenesis of this complex

  17. Information overload, choice deferral, and moderating role of need for cognition: Empirical evidence

    Directory of Open Access Journals (Sweden)

    Luis Eduardo Pilli

    2016-03-01

    Full Text Available ABSTRACT Choice deferral due to information overload is an undesirable result of competitive environments. The neoclassical maximization models predict that choice avoidance will not increase as more information is offered to consumers. The theories developed in the consumer behavior field predict that some properties of the environment may lead to behavioral effects and an increase in choice avoidance due to information overload. Based on stimuli generated experimentally and tested among 1,000 consumers, this empirical research provides evidence for the presence of behavioral effects due to information overload and reveals the different effects of increasing the number of options or the number of attributes. This study also finds that the need for cognition moderates these behavioral effects, and it proposes psychological processes that may trigger the effects observed.

  18. Maximally Rotating Supermassive Stars at the Onset of Collapse: The Perturbative Effects of Gas Pressure, Magnetic Fields, Dark Matter and Dark Energy

    Science.gov (United States)

    Butler, Satya P.; Lima, Alicia R.; Baumgarte, Thomas W.; Shapiro, Stuart L.

    2018-04-01

    The discovery of quasars at increasingly large cosmological redshifts may favor "direct collapse" as the most promising evolutionary route to the formation of supermassive black holes. In this scenario, supermassive black holes form when their progenitors - supermassive stars - become unstable to gravitational collapse. For uniformly rotating stars supported by pure radiation pressure and spinning at the mass-shedding limit, the critical configuration at the onset of collapse is characterized by universal values of the dimensionless spin and radius parameters J/M2 and R/M, independent of mass M. We consider perturbative effects of gas pressure, magnetic fields, dark matter and dark energy on these parameters, and thereby determine the domain of validity of this universality. We obtain leading-order corrections for the critical parameters and establish their scaling with the relevant physical parameters. We compare two different approaches to approximate the effects of gas pressure, which plays the most important role, find identical results for the above dimensionless parameters, and also find good agreement with recent numerical results.

  19. Quantitative estimation of the right ventricular overloading by thallium-201 myocardial scintigraphy

    International Nuclear Information System (INIS)

    Owada, Kenji; Machii, Kazuo; Tsukahara, Yasunori

    1982-01-01

    Thallium-201 myocardial scintigraphy was performed on 55 patients with various types of right ventricular overloading. The right ventricular (RV) free wall was visualized in 39 out of the 55 patients (71%). The mean values of right ventricular systolic pressure (RVSP) and pulmonary artery mean pressure (PAMP) in the visualized cases (uptakers) were 54.6 +- 24.1 and 30.5 +- 15.3 mmHg, respectively. These values were significantly higher than those of the non-visualized cases (non-uptakers). There were 12 RVSP-''normotensive'' uptakers and 15 PAMP-''normotensive'' uptakers. The RV free wall images were classified into three types according to their morphological features. Type I was predominantly seen in cases of RV pressure overloading, type II in RV volume overloading and type III in combined ventricular overloading. RVSP in the type III group was significantly higher than that in other two groups. The radioactivity ratio in RV free wall and interventricular septum (IVS), the RV/IVS uptake ratio was calculated using left anterior oblique (LAO) view images. The RV/IVS uptake ratio closely correlated with RVSP and PAMP (r = 0.88 and 0.82, respectively). In each group of RV free wall image, there were also close correlations between the RV/IVS uptake ratio and both RVSP and PAMP. Our results indicate that the RV/IVS uptake ratio can be used as a parameter for the semi-quantitative estimation of right ventricular overloading. (author)

  20. Maximally incompatible quantum observables

    Energy Technology Data Exchange (ETDEWEB)

    Heinosaari, Teiko, E-mail: teiko.heinosaari@utu.fi [Turku Centre for Quantum Physics, Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Schultz, Jussi, E-mail: jussi.schultz@gmail.com [Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Toigo, Alessandro, E-mail: alessandro.toigo@polimi.it [Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy); Ziman, Mario, E-mail: ziman@savba.sk [RCQI, Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 84511 Bratislava (Slovakia); Faculty of Informatics, Masaryk University, Botanická 68a, 60200 Brno (Czech Republic)

    2014-05-01

    The existence of maximally incompatible quantum observables in the sense of a minimal joint measurability region is investigated. Employing the universal quantum cloning device it is argued that only infinite dimensional quantum systems can accommodate maximal incompatibility. It is then shown that two of the most common pairs of complementary observables (position and momentum; number and phase) are maximally incompatible.

  1. Maximally incompatible quantum observables

    International Nuclear Information System (INIS)

    Heinosaari, Teiko; Schultz, Jussi; Toigo, Alessandro; Ziman, Mario

    2014-01-01

    The existence of maximally incompatible quantum observables in the sense of a minimal joint measurability region is investigated. Employing the universal quantum cloning device it is argued that only infinite dimensional quantum systems can accommodate maximal incompatibility. It is then shown that two of the most common pairs of complementary observables (position and momentum; number and phase) are maximally incompatible.

  2. Achieving quasi-adiabatic thermal environment to maximize resolution power in very high-pressure liquid chromatography: Theory, models, and experiments.

    Science.gov (United States)

    Gritti, Fabrice; Gilar, Martin; Jarrell, Joseph A

    2016-04-29

    A cylindrical vacuum chamber (inner diameter 5 cm) housing a narrow-bore 2.1 mm×100 mm column packed with 1.8 μm HSS-T3 fully porous particles was built in order to isolate thermally the chromatographic column from the external air environment. Consistent with statistical physics and the mean free path of air molecules, the experimental results show that natural air convection and conduction are fully eliminated for housing air pressures smaller than 10(-4) Torr. Heat radiation is minimized by wrapping up the column with low-emissivity aluminum-tape (emissivity coefficient ϵ=0.03 vs. 0.28 for polished stainless steel 316). Overall, the heat flux at the column wall is reduced by 96% with respect to standard still-air ovens. From a practical viewpoint, the efficiency of the column run at a flow rate of 0.6 mL/min at a constant 13,000 psi pressure drop (the viscous heat power is around 9 W/m) is improved by up to 35% irrespective of the analyte retention. Models of heat and mass transfer reveal that (1) the amplitude of the radial temperature gradient is significantly reduced from 0.30 to 0.01 K and (2) the observed improvement in resolution power stems from a more uniform distribution of the flow velocity across the column diameter. The eddy dispersion term in the van Deemter equation is reduced by 0.8±0.1 reduced plate height unit, a significant gain in column performance. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Overload protection system for power inverter

    Science.gov (United States)

    Nagano, S. (Inventor)

    1977-01-01

    An overload protection system for a power inverter utilized a first circuit for monitoring current to the load from the power inverter to detect an overload and a control circuit to shut off the power inverter, when an overload condition was detected. At the same time, a monitoring current inverter was turned on to deliver current to the load at a very low power level. A second circuit monitored current to the load, from the monitoring current inverter, to hold the power inverter off through the control circuit, until the overload condition was cleared so that the control circuit may be deactivated in order for the power inverter to be restored after the monitoring current inverter is turned off completely.

  4. Overload Control in a SIP Signaling Network

    OpenAIRE

    Masataka Ohta

    2007-01-01

    The Internet telephony employs a new type of Internet communication on which a mutual communication is realized by establishing sessions. Session Initiation Protocol (SIP) is used to establish sessions between end-users. For unreliable transmission (UDP), SIP message should be retransmitted when it is lost. The retransmissions increase a load of the SIP signaling network, and sometimes lead to performance degradation when a network is overloaded. The paper proposes an overload control for a S...

  5. Thermal Characterization of the Overload Carbon Resistors

    Directory of Open Access Journals (Sweden)

    Ivana Kostić

    2013-01-01

    Full Text Available In many applications, the electronic component is not continuously but only intermittently overloaded (e.g., inrush current, short circuit, or discharging interference. With this paper, we provide insight into carbon resistors that have to hold out a rarely occurring transient overload. Using simple electrical circuit, the resistor is overheating with higher current than declared, and dissipation is observed by a thermal camera.

  6. Maximizers versus satisficers

    OpenAIRE

    Andrew M. Parker; Wandi Bruine de Bruin; Baruch Fischhoff

    2007-01-01

    Our previous research suggests that people reporting a stronger desire to maximize obtain worse life outcomes (Bruine de Bruin et al., 2007). Here, we examine whether this finding may be explained by the decision-making styles of self-reported maximizers. Expanding on Schwartz et al. (2002), we find that self-reported maximizers are more likely to show problematic decision-making styles, as evidenced by self-reports of less behavioral coping, greater dependence on others when making decisions...

  7. Maximal combustion temperature estimation

    International Nuclear Information System (INIS)

    Golodova, E; Shchepakina, E

    2006-01-01

    This work is concerned with the phenomenon of delayed loss of stability and the estimation of the maximal temperature of safe combustion. Using the qualitative theory of singular perturbations and canard techniques we determine the maximal temperature on the trajectories located in the transition region between the slow combustion regime and the explosive one. This approach is used to estimate the maximal temperature of safe combustion in multi-phase combustion models

  8. Ischemic preconditioning improves mitochondrial tolerance to experimental calcium overload.

    Science.gov (United States)

    Crestanello, Juan A; Doliba, Nicolai M; Babsky, Andriy M; Doliba, Natalia M; Niibori, Koki; Whitman, Glenn J R; Osbakken, Mary D

    2002-04-01

    Ca(2+) overload leads to mitochondrial uncoupling, decreased ATP synthesis, and myocardial dysfunction. Pharmacologically opening of mitochondrial K(ATP) channels decreases mitochondrial Ca(2+) uptake, improving mitochondrial function during Ca(2+) overload. Ischemic preconditioning (IPC), by activating mitochondrial K(ATP) channels, may attenuate mitochondrial Ca(2+) overload and improve mitochondrial function during reperfusion. The purpose of these experiments was to study the effect of IPC (1) on mitochondrial function and (2) on mitochondrial tolerance to experimental Ca(2+) overload. Rat hearts (n = 6/group) were subjected to (a) 30 min of equilibration, 25 min of ischemia, and 30 min of reperfusion (Control) or (b) two 5-min episodes of ischemic preconditioning, 25 min of ischemia, and 30 min of reperfusion (IPC). Developed pressure (DP) was measured. Heart mitochondria were isolated at end-Equilibration (end-EQ) and at end-Reperfusion (end-RP). Mitochondrial respiratory function (state 2, oxygen consumption with substrate only; state 3, oxygen consumption stimulated by ADP; state 4, oxygen consumption after cessation of ADP phosphorylation; respiratory control index (RCI, state 3/state 4); rate of oxidative phosphorylation (ADP/Deltat), and ADP:O ratio) was measured with polarography using alpha-ketoglutarate as a substrate in the presence of different Ca(2+) concentrations (0 to 5 x 10(-7) M) to simulate Ca(2+) overload. IPC improved DP at end-RP. IPC did not improve preischemic mitochondrial respiratory function or preischemic mitochondrial response to Ca(2+) loading. IPC improved state 3, ADP/Deltat, and RCI during RP. Low Ca(2+) levels (0.5 and 1 x 10(-7) M) stimulated mitochondrial function in both groups predominantly in IPC. The Control group showed evidence of mitochondrial uncoupling at lower Ca(2+) concentrations (1 x 10(-7) M). IPC preserved state 3 at high Ca(2+) concentrations. The cardioprotective effect of IPC results, in part, from

  9. Maximally multipartite entangled states

    Science.gov (United States)

    Facchi, Paolo; Florio, Giuseppe; Parisi, Giorgio; Pascazio, Saverio

    2008-06-01

    We introduce the notion of maximally multipartite entangled states of n qubits as a generalization of the bipartite case. These pure states have a bipartite entanglement that does not depend on the bipartition and is maximal for all possible bipartitions. They are solutions of a minimization problem. Examples for small n are investigated, both analytically and numerically.

  10. Maximizers versus satisficers

    Directory of Open Access Journals (Sweden)

    Andrew M. Parker

    2007-12-01

    Full Text Available Our previous research suggests that people reporting a stronger desire to maximize obtain worse life outcomes (Bruine de Bruin et al., 2007. Here, we examine whether this finding may be explained by the decision-making styles of self-reported maximizers. Expanding on Schwartz et al. (2002, we find that self-reported maximizers are more likely to show problematic decision-making styles, as evidenced by self-reports of less behavioral coping, greater dependence on others when making decisions, more avoidance of decision making, and greater tendency to experience regret. Contrary to predictions, self-reported maximizers were more likely to report spontaneous decision making. However, the relationship between self-reported maximizing and worse life outcomes is largely unaffected by controls for measures of other decision-making styles, decision-making competence, and demographic variables.

  11. Oligofructose overload induces lameness in cattle.

    Science.gov (United States)

    Danscher, A M; Enemark, J M D; Telezhenko, E; Capion, N; Ekstrøm, C T; Thoefner, M B

    2009-02-01

    The aim was to describe the clinical orthopedic implications of oligofructose overload. A group of 8 nonpregnant dairy heifers were given an oral dose of oligofructose (17 g/kg of body weight). At predefined times during a period spanning 3 d before and 9 d after oligofructose overload, the heifers underwent a clinical examination including locomotion scoring, hoof-testing, and palpation of tarso-crural joints, as well as the collection of blood and ruminal fluid samples. Locomotion sessions were videotaped; subsequently, locomotion was blind-scored. Locomotion scores increased after oligofructose overload and declined toward the end of the study period. The greatest locomotion scores were recorded on d 3 to 5 (60 to 120 h) where 12 of 42 (29%) locomotion scores were 3 and 13 of 42 (32%) were score 2. Positive reactions to hoof-testing were observed from 30 h after oligofructose overload and reached a maximum on d 7 and 9 where 12 of 28 (43%) reactions were marked positive. Distension of the tarso-crural joints was observed from 24 h after oligofructose overload, with maximum distension being observed on d 2, in which 44 of 56 (79%) of observed joints were either moderately or severely distended. The heifers developed classic signs of acute ruminal and systemic acidosis after the oligofructose overload (ruminal pH 4.3 +/- 0.07, standard base excess -10.8 +/- 2.3 at 18 h). With few exceptions, clinical and laboratory variables returned to normal within 9 d of oligofructose overload. But, good body condition and previous feeding with grass apparently predisposed the heifers to more severe systemic affection. Oligofructose overload in dairy heifers induced ruminal and systemic acidosis, diarrhea, dehydration, and, subsequently, lameness, claw pain, and joint effusion, collectively interpreted as signs of acute laminitis. Oligofructose overload at 17 g/kg of body weight represented a relatively mild laminitis model in cattle, as demonstrated by a reasonably quick

  12. Physical activity behavior and role overload in mothers.

    Science.gov (United States)

    Lovell, Geoff P; Butler, Frances R

    2015-01-01

    We examined physical activity stages of change, physical activity behavior, and role overload in different stages of motherhood in a predominantly Australian sample. Neither physical activity behavior, stages of physical activity change, nor role overload significantly differed across motherhood groups. Role overload was significantly higher for mothers in the contemplation, planning, and action stages of physical activity than in the maintenance stage of change. Role overload had a weak, although significant, negative correlation with leisure-time physical activity. We conclude that strategies focused upon reducing role overload or perceived role overload have only limited potential to meaningfully increase leisure-time physical activity in mothers.

  13. Is CP violation maximal

    International Nuclear Information System (INIS)

    Gronau, M.

    1984-01-01

    Two ambiguities are noted in the definition of the concept of maximal CP violation. The phase convention ambiguity is overcome by introducing a CP violating phase in the quark mixing matrix U which is invariant under rephasing transformations. The second ambiguity, related to the parametrization of U, is resolved by finding a single empirically viable definition of maximal CP violation when assuming that U does not single out one generation. Considerable improvement in the calculation of nonleptonic weak amplitudes is required to test the conjecture of maximal CP violation. 21 references

  14. Control over Permissible Short Emergency Overloads in Power Transformers

    Directory of Open Access Journals (Sweden)

    V. A. Anischenko

    2010-01-01

    Full Text Available The paper proposes a method for determination a permissible duration of short intermittent overloads of power transformers that permits to avoid non-permissible over-heating of winding insulation and fully utilize overloading transformer ability.

  15. Iron overload in myelodysplastic syndromes (MDS).

    Science.gov (United States)

    Gattermann, Norbert

    2018-01-01

    Iron overload (IOL) starts to develop in MDS patients before they become transfusion-dependent because ineffective erythropoiesis suppresses hepcidin production in the liver and thus leads to unrestrained intestinal iron uptake. However, the most important cause of iron overload in MDS is chronic transfusion therapy. While transfusion dependency by itself is a negative prognostic factor reflecting poor bone marrow function, the ensuing transfusional iron overload has an additional dose-dependent negative impact on the survival of patients with lower risk MDS. Cardiac dysfunction appears to be important in this context, as a consequence of chronic anemia, age-related cardiac comorbidity, and iron overload. Another potential problem is iron-related endothelial dysfunction. There is some evidence that with increasing age, high circulating iron levels worsen the atherosclerotic phenotype. Transfusional IOL also appears to aggravate bone marrow failure in MDS, through unfavorable effects on mesenchymal stromal cells as well a hematopoietic cells, particularly erythroid precursors. Patient series and clinical trials have shown that the iron chelators deferoxamine and deferasirox can improve hematopoiesis in a minority of transfusion-dependent patients. Analyses of registry data suggest that iron chelation provides a survival benefit for patients with MDS, but data from a prospective randomized clinical trial are still lacking.

  16. Effect of anabolic steroids on overloaded and overloaded suspended skeletal muscle

    Science.gov (United States)

    Tsika, R. W.; Herrick, R. E.; Baldwin, K. M.

    1987-01-01

    The effect of treatment with an anabolic steroid (nandrolone decanoate) on the muscle mass, the subcellular protein content, and the myosin patterns of normal overloaded and suspended overloaded plantaris muscle in female rat was investigated, dividing rats into six groups: normal control (NC), overload (OV), OV steroid (OV-S), normal suspended (N-sus), OV suspended (OV-sus), and OV suspended steroid (OV-sus-S). Relative to control values, overload produced a sparing effect on the muscle weight of the OV-sus group as well as increases of muscle weight of the OV group; increased protein content; and an increased expression of slow myosin in both OV and OV-sus groups. Steroid treatment of OV animals did not after the response of any parameter analyzed for the OV group, but in the OV-sus group steroid treatment induced increases in muscle weight and in protein content of the OV-sus-S group. The treatment did not alter the pattern of isomyosin expression observed in the OV or the OV-sus groups. These result suggest that the steroid acts synergistically with functional overload only under conditions in which the effect of overload is minimized by suspension.

  17. Volume overload and adverse outcomes in chronic kidney disease: clinical observational and animal studies.

    Science.gov (United States)

    Hung, Szu-Chun; Lai, Yi-Shin; Kuo, Ko-Lin; Tarng, Der-Cherng

    2015-05-05

    Volume overload is frequently encountered and is associated with cardiovascular risk factors in patients with chronic kidney disease (CKD). However, the relationship between volume overload and adverse outcomes in CKD is not fully understood. A prospective cohort of 338 patients with stage 3 to 5 CKD was followed for a median of 2.1 years. The study participants were stratified by the presence or absence of volume overload, defined as an overhydration index assessed by bioimpedance spectroscopy exceeding 7%, the 90th percentile for the healthy population. The primary outcome was the composite of estimated glomerular filtration rate decline ≥50% or end-stage renal disease. The secondary outcome included a composite of morbidity and mortality from cardiovascular causes. Animal models were used to simulate fluid retention observed in human CKD. We found that patients with volume overload were at a higher risk of the primary and secondary end points in the adjusted Cox models. Furthermore, overhydration appears to be more important than hypertension in predicting an elevated risk. In rats subjected to unilateral nephrectomy and a high-salt diet, the extracellular water significantly increased. This fluid retention was associated with an increase in blood pressure, proteinuria, renal inflammation with macrophage infiltration and tumor necrosis factor-α overexpression, glomerular sclerosis, and cardiac fibrosis. Diuretic treatment with indapamide attenuated these changes, suggesting that fluid retention might play a role in the development of adverse outcomes. Volume overload contributes to CKD progression and cardiovascular diseases. Further research is warranted to clarify whether the correction of volume overload would improve outcomes for CKD patients. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  18. Vzájemný vztah mezi mobilitou a maximálním uzávěrovým tlakem uretry či Valsalva Leak-Point Pressure u žen se stresovým typem inkontince moči

    Czech Academy of Sciences Publication Activity Database

    Martan, A.; Mašata, J.; Švabík, K.; Drahorádová, P.; Hlásenská, Jana; Pavlíková, Markéta

    2005-01-01

    Roč. 70, č. 4 (2005), s. 123-128 ISSN 1210-7832 R&D Projects: GA MZd NH7378 Keywords : inkontinence moči u žen * hypermobilita uretry * maximální uzávěrový tlak uretry * Valsalva leak -point pressure Subject RIV: FK - Gynaecology, Childbirth

  19. Vzájemný vztah maximálního uzávěrového tlaku uretry a Valsalva Leak-Point Pressure u žen se stresovým typem inkontince moči

    Czech Academy of Sciences Publication Activity Database

    Martan, A.; Mašata, J.; Švabík, K.; Drahorádová, P.; Halaška, M.; Voigt, R.; Pavlíková, Markéta

    2004-01-01

    Roč. 69, č. 4 (2004), s. 267-272 ISSN 1210-7832 R&D Projects: GA MZd NH7378 Keywords : inkontinence moči u žen * maximální uzávěrový tlak uretry * Valsalva leak -point pressure Subject RIV: FK - Gynaecology, Childbirth

  20. Guinea pig maximization test

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner

    1985-01-01

    Guinea pig maximization tests (GPMT) with chlorocresol were performed to ascertain whether the sensitization rate was affected by minor changes in the Freund's complete adjuvant (FCA) emulsion used. Three types of emulsion were evaluated: the oil phase was mixed with propylene glycol, saline...

  1. Tri-maximal vs. bi-maximal neutrino mixing

    International Nuclear Information System (INIS)

    Scott, W.G

    2000-01-01

    It is argued that data from atmospheric and solar neutrino experiments point strongly to tri-maximal or bi-maximal lepton mixing. While ('optimised') bi-maximal mixing gives an excellent a posteriori fit to the data, tri-maximal mixing is an a priori hypothesis, which is not excluded, taking account of terrestrial matter effects

  2. An Improved Overloading Scheme for Downlink CDMA

    Directory of Open Access Journals (Sweden)

    Marc Moeneclaey

    2005-04-01

    Full Text Available An improved overloading scheme is presented for single-user detection in the downlink of multiple-access systems based on OCDMA/OCDMA (O/O. By displacing in time the orthogonal signatures of the two user sets that make up the overloaded system, the cross-correlation between the users of the two sets is reduced. For random O/O with square-root cosine rolloff chip pulses, the multiuser interference can be decreased by up to 50% (depending on the chip pulse bandwidth as compared to quasiorthogonal sequences (QOS that are presently part of the downlink standard of Cdma2000. This reduction of the multiuser interference gives rise to an increase of the achievable signal-to-interference-plus-noise ratio for a particular channel load.

  3. Hepatic iron overload: Quantitative MR imaging

    International Nuclear Information System (INIS)

    Gomori, J.M.; Horev, G.; Tamary, H.; Zandback, J.; Kornreich, L.; Zaizov, R.; Freud, E.; Krief, O.; Ben-Meir, J.; Rotem, H.

    1991-01-01

    Iron deposits demonstrate characteristically shortened T2 relaxation times. Several previously published studies reported poor correlation between the in vivo hepatic 1/T2 measurements made by means of midfield magnetic resonance (MR) units and the hepatic iron content of iron-overloaded patients. In this study, the authors assessed the use of in vivo 1/T2 measurements obtained by means of MR imaging at 0.5 T using short echo times (13.4 and 30 msec) and single-echo-sequences as well as computed tomographic (CT) attenuation as a measure of liver iron concentration in 10 severely iron-overloaded patients with beta-thalassemia major. The iron concentrations in surgical wedge biopsy samples of the liver, which varied between 3 and 9 mg/g of wet weight (normal, less than or equal to 0.5 mg/g), correlated well (r = .93, P less than or equal to .0001) with the preoperative in vivo hepatic 1/T2 measurements. The CT attenuation did not correlate with liver iron concentration. Quantitative MR imaging is a readily available noninvasive method for the assessment of hepatic iron concentration in iron-overloaded patients, reducing the need for needle biopsies of the liver

  4. Iron overload impact on P-ATPases.

    Science.gov (United States)

    Sousa, Leilismara; Pessoa, Marco Tulio C; Costa, Tamara G F; Cortes, Vanessa F; Santos, Herica L; Barbosa, Leandro Augusto

    2018-03-01

    Iron is a chemical element that is active in the fundamental physiological processes for human life, but its burden can be toxic to the body, mainly because of the stimulation of membrane lipid peroxidation. For this reason, the action of iron on many ATPases has been studied, especially on P-ATPases, such as the Na + ,K + -ATPase and the Ca 2+ -ATPase. On the Fe 2+ -ATPase activity, the free iron acts as an activator, decreasing the intracellular Fe 2+ and playing a protection role for the cell. On the Ca 2+ -ATPase activity, the iron overload decreases the enzyme activity, raising the cytoplasmic Ca 2+ and decreasing the sarco/endoplasmic reticulum and the Golgi apparatus Ca 2+ concentrations, which could promote an enzyme oxidation, nitration, and fragmentation. However, the iron overload effect on the Na + ,K + -ATPase may change according to the tissue expressions. On the renal cells, as well as on the brain and the heart, iron promotes an enzyme inactivation, whereas its effect on the erythrocytes seems to be the opposite, directly stimulating the ATPase activity, or stimulating it by signaling pathways involving ROS and PKC. Modulations in the ATPase activity may impair the ionic transportation, which is essential for cell viability maintenance, inducing irreversible damage to the cell homeostasis. Here, we will discuss about the iron overload effect on the P-ATPases, such as the Na + ,K + -ATPase, the Ca 2+ -ATPase, and the Fe 2+ -ATPase.

  5. Protein quality control in protection against systolic overload cardiomyopathy: the long term role of small heat shock proteins.

    Science.gov (United States)

    Kumarapeli, Asangi R K; Horak, Kathleen; Wang, Xuejun

    2010-07-21

    Molecular chaperones represent the first line of defense of intracellular protein quality control. As a major constituent of molecular chaperones, heat shock proteins (HSP) are known to confer cardiomyocyte short-term protection against various insults and injuries. Previously, we reported that the small HSP alphaB-crystallin (CryAB) attenuates cardiac hypertrophic response in mice subjected to 2 weeks of severe pressure overload. However, the long-term role of small HSPs in cardiac hypertrophy and failure has rarely been studied. The present study investigates the cardiac responses to chronic severe pressure overload in CryAB/HSPB2 germ line ablated (KO) and cardiac-specific CryAB overexpressingtransgenic (TG) mice. Pressure overload was induced by transverse aortic constriction in KO, TG, and non-transgenic wild type (NTG) control mice and 10 weeks later molecular, cellular, and whole organ level hypertrophic responses were analyzed. As we previously described, CryAB/HSPB2 KO mice showed abnormal baseline cardiac physiology that worsened into a restrictive cardiomyopathic phenotype with aging. Severe pressure overload in these mice led to rapid deterioration of heart function and development of congestive cardiac failure. Contrary to their short term protective phenotype, CryAB TG mice showed no significant effects on cardiac hypertrophic responses and very modest improvement of hemodynamics during chronic systolic overload. These findings indicate that small HSPs CryAB and/or HSPB2 are essential to maintain cardiac structure and function but overex-pression of CryAB is not sufficient to confer a sustained protection against chronic systolic overload.

  6. Reduced firing rates of high threshold motor units in response to eccentric overload.

    Science.gov (United States)

    Balshaw, Tom G; Pahar, Madhu; Chesham, Ross; Macgregor, Lewis J; Hunter, Angus M

    2017-01-01

    Acute responses of motor units were investigated during submaximal voluntary isometric tasks following eccentric overload (EO) and constant load (CL) knee extension resistance exercise. Ten healthy resistance-trained participants performed four experimental test sessions separated by 5 days over a 20 day period. Two sessions involved constant load and the other two used eccentric overload. EO and CL used both sessions for different target knee eccentric extension phases; one at 2 sec and the other at 4 sec. Maximal voluntary contractions (MVC) and isometric trapezoid efforts for 10 sec at 70% MVC were completed before and after each intervention and decomposed electromyography was used to measure motor unit firing rate. The firing rate of later recruited, high-threshold motor units declined following the 2-sec EO but was maintained following 2sec CL (P motor units were maintained for both loading types following 4-sec extension phases. MVC and rate of force development where maintained following both EO and CL and 2 and 4 sec phases. This study demonstrates a slower firing rate of high-threshold motor units following fast eccentric overload while MVC was maintained. This suggests that there was a neuromuscular stimulus without cost to the force-generating capacity of the knee extensors. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  7. MAXIM: The Blackhole Imager

    Science.gov (United States)

    Gendreau, Keith; Cash, Webster; Gorenstein, Paul; Windt, David; Kaaret, Phil; Reynolds, Chris

    2004-01-01

    The Beyond Einstein Program in NASA's Office of Space Science Structure and Evolution of the Universe theme spells out the top level scientific requirements for a Black Hole Imager in its strategic plan. The MAXIM mission will provide better than one tenth of a microarcsecond imaging in the X-ray band in order to satisfy these requirements. We will overview the driving requirements to achieve these goals and ultimately resolve the event horizon of a supermassive black hole. We will present the current status of this effort that includes a study of a baseline design as well as two alternative approaches.

  8. Social group utility maximization

    CERN Document Server

    Gong, Xiaowen; Yang, Lei; Zhang, Junshan

    2014-01-01

    This SpringerBrief explains how to leverage mobile users' social relationships to improve the interactions of mobile devices in mobile networks. It develops a social group utility maximization (SGUM) framework that captures diverse social ties of mobile users and diverse physical coupling of mobile devices. Key topics include random access control, power control, spectrum access, and location privacy.This brief also investigates SGUM-based power control game and random access control game, for which it establishes the socially-aware Nash equilibrium (SNE). It then examines the critical SGUM-b

  9. Reducing maternal mortality: Systolic blood pressure

    African Journals Online (AJOL)

    2006-03-21

    Mar 21, 2006 ... While deaths due to fluid overload have ... of better fluid balance management, we have made .... systolic blood pressure plays a significant role in the .... one looks at the work of Martin et al.5 ... Promoting Healthy Life.

  10. Quantitative evaluation of right ventricular overload with thallium-201 myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Watanabe, Toshiya; Miyakoda, Hiroyuki; Koike, Yoshihiro; Itatsu, Hidetaka; Kawai, Naoki; Sotobata, Iwao.

    1983-01-01

    Thallium-201 myocardial perfusion scintigraphy and right-heart catheterization were performed on patients with right ventricular pressure overload (RVPO) or right ventricular volume overload (RVVO). In 18 patients with RVPO, right ventricular systolic pressure correlated significantly both with the RV/LV wall thallium-201 uptake ratios (r=0.54, p<0.02) and the RV wall/background thallium-201 uptake ratios (r=0.70, p<0.01). RV/LV work ratios also significantly correlated with RV/LV wall thallium-201 uptake ratios (r=0.57, p<0.02). In 19 patients with RVVO, Qp/Qs and RV/LV work ratios both significantly correlated with RV/LV wall thallium-201 uptake ratios (r=0.78 and 0.87, respectively; p<0.001 for both) and RV wall/background thallium-201 uptake ratios (r=0.69, p<0.01 for both parameters). Right ventricular systolic pressure also correlated with RV/LV wall thallium-201 uptake ratios (r=0.57, p<0.02). Feasibility of the differentiation between RVPO and RVVO was suggested with use of ''transitional view angle'' and RV/LV diameter ratios obtained from the scintigram. In patients who underwent cardiac surgery, post-operative alleviations of the right ventricular overload were evaluated. There was a significant decrease in RV/LV wall thallium-201 uptake ratios, but no significant decrease in RV wall/background thallium-201 uptake ratios in patients with RVPO. On the other hand, there was a significant decrease both in RV/LV wall thallium-201 uptake ratios and RV wall/background thallium-201 uptake ratios in patients with RVVO. No significant changes were observed between the scintigraphic measurements obtained 1 month and 1 year after the surgery, irrespective of the type of right ventricular overloading. (J.P.N.)

  11. TNF-α as a potential mediator of cardiac dysfunction due to intracellular Ca2+-overload

    International Nuclear Information System (INIS)

    Zhang Ming; Xu Yanjun; Saini, Harjot K.; Turan, Belma; Liu, Peter P.; Dhalla, Naranjan S.

    2005-01-01

    TNF-α has been shown to be involved in cardiac dysfunction during ischemia/reperfusion injury; however, no information regarding the status of TNF-α production in myocardial injury due to intracellular Ca 2+ -overload is available in the literature. The intracellular Ca 2+ -overload was induced in the isolated rat hearts subjected to 5 min Ca 2+ -depletion and 30 min Ca 2+ -repletion (Ca 2+ -paradox). The Ca 2+ -paradox hearts exhibited a dramatic depression in left ventricular developed pressure, a marked elevation in left ventricular end diastolic pressure, and more than a 4-fold increase in TNF-α content. The ratio of cytosolic to homogenate nuclear factor-κB (NFκB) was decreased whereas the ratio of phospho-NFκB to total NFκB was increased in the Ca 2+ -paradox hearts. All these changes due to Ca 2+ -paradox were significantly attenuated upon treating the hearts with 100 μM pentoxifylline. These results suggest that activation of NFκB and increased production of TNF-α may play an important role in cardiac injury due to intracellular Ca 2+ -overload

  12. Dietary Fat Overload Reprograms Brown Fat Mitochondria

    Directory of Open Access Journals (Sweden)

    DANIELE eLETTIERI BARBATO

    2015-09-01

    Full Text Available Chronic nutrient overload accelerates the onset of several aging-related diseases reducing life expectancy. Although the mechanisms by which overnutrition affects metabolic processes in many tissues are known, its role on BAT physiology is still unclear. Herein, we investigated the mitochondrial responses in BAT of female mice exposed to high fat diet (HFD at different steps of life. Although adult mice showed an unchanged mitochondrial amount, both respiration and OxPHOS subunits were strongly affected. Differently, offspring pups exposed to HFD during pregnancy and lactation displayed reduced mitochondrial mass but high oxidative efficiency that, however, resulted in increased bioenergetics state of BAT rather than augmented uncoupling respiration. Interestingly, the metabolic responses triggered by HFD were accompanied by changes in mitochondrial dynamics characterized by decreased content of the fragmentation marker Drp1 both in mothers and offspring pups. HFD-induced inactivation of the FoxO1 transcription factor seemed to be the up-stream modulator of Drp1 levels in brown fat cells. Furthermore, HFD offspring pups weaned with normal diet only partially reverted the mitochondrial dysfunctions caused by HFD. Finally these mice failed in activating the thermogenic program upon cold exposure. Collectively our findings suggest that maternal dietary fat overload irreversibly commits BAT unresponsiveness to physiological stimuli such as cool temperature and this dysfunction in the early stage of life might negatively modulates health and lifespan.

  13. Investigating turnover intentions by role overload, job satisfaction and social support moderation

    Directory of Open Access Journals (Sweden)

    J Pienaar

    2007-01-01

    Full Text Available Gold mining in South Africa has played a significant role in the economic development of the country. However, the current economic, personnel and rationalisation pressures could imply a loss of production in this industry. The focus of this research fell on investigating the role that social support may play in the translation of employees’ role overload and job satisfaction on their intentions to leave the organisation. A cross-sectional survey design with a random sample was used (n = 206. Results indicate that job satisfaction is the most significant predictor of turnover intention, but that collegial support plays an important role in moderating the effects of role overload on turnover intention.

  14. Hypertrophic response to hemodynamic overload: role of load vs. renin-angiotensin system activation

    Science.gov (United States)

    Koide, M.; Carabello, B. A.; Conrad, C. C.; Buckley, J. M.; DeFreyte, G.; Barnes, M.; Tomanek, R. J.; Wei, C. C.; Dell'Italia, L. J.; Cooper, G. 4th; hide

    1999-01-01

    Myocardial hypertrophy is one of the basic mechanisms by which the heart compensates for hemodynamic overload. The mechanisms by which hemodynamic overload is transduced by the cardiac muscle cell and translated into cardiac hypertrophy are not completely understood. Candidates include activation of the renin-angiotensin system (RAS) and angiotensin II receptor (AT1) stimulation. In this study, we tested the hypothesis that load, independent of the RAS, is sufficient to stimulate cardiac growth. Four groups of cats were studied: 14 normal controls, 20 pulmonary artery-banded (PAB) cats, 7 PAB cats in whom the AT1 was concomitantly and continuously blocked with losartan, and 8 PAB cats in whom the angiotensin-converting enzyme (ACE) was concomitantly and continuously blocked with captopril. Losartan cats had at least a one-log order increase in the ED50 of the blood pressure response to angiotensin II infusion. Right ventricular (RV) hypertrophy was assessed using the RV mass-to-body weight ratio and ventricular cardiocyte size. RV hemodynamic overload was assessed by measuring RV systolic and diastolic pressures. Neither the extent of RV pressure overload nor RV hypertrophy that resulted from PAB was affected by AT1 blockade with losartan or ACE inhibition with captopril. RV systolic pressure was increased from 21 +/- 3 mmHg in normals to 68 +/- 4 mmHg in PAB, 65 +/- 5 mmHg in PAB plus losartan and 62 +/- 3 mmHg in PAB plus captopril. RV-to-body weight ratio increased from 0.52 +/- 0.04 g/kg in normals to 1.11 +/- 0.06 g/kg in PAB, 1.06 +/- 0.06 g/kg in PAB plus losartan and 1.06 +/- 0.06 g/kg in PAB plus captopril. Thus 1) pharmacological modulation of the RAS with losartan and captopril did not change the extent of the hemodynamic overload or the hypertrophic response induced by PAB; 2) neither RAS activation nor angiotensin II receptor stimulation is an obligatory and necessary component of the signaling pathway that acts as an intermediary coupling load to the

  15. Iron overload following bone marrow transplantation in children: MR findings

    International Nuclear Information System (INIS)

    Kornreich, L.; Horev, G.; Grunebaum, M.; Yaniv, I.; Stein, J.; Zaizov, R.

    1997-01-01

    Objective. The purpose of this study was to determine the incidence of post-transfusional iron overload in children after bone marrow transplantation by reviewing their magnetic resonance imaging (MR) findings. Materials and methods. We reviewed the abdominal MR studies of 13 children after autologous bone marrow transplantation. Nine of the children had also undergone MR prior to transplantation. Iron deposition in the liver, spleen and bone marrow was graded semi-quantitatively on both T1- and T2-weighted images. Serum ferritin levels and number of blood units given after bone marrow transplantation were recorded. Results. None of the pre-transplantation MR studies revealed iron overload. After bone marrow transplantation, three children showed normal liver and spleen. Iron overload in the liver was noted in ten patients (77 %), six of whom also showed iron overload in the spleen (46 %) and five in the bone marrow (38.5 %). The degree of hepatic iron overload was correlated significantly and splenic iron overload was correlated weakly with the number of blood transfusions (P 0.01 and P > 0.01, respectively), but neither was correlated with the serum ferritin level. Conclusion. Iron overload commonly accompanies bone marrow transplantation. The observed pattern of iron deposition, in which the spleen was uninvolved in 40 % of patients demonstrating iron overload, is not typical of post-transfusional hemochromatosis. (orig.)

  16. Using Pattern Recognition Techniques for Server Overload Detection

    NARCIS (Netherlands)

    Bezemer, C.P.; Cheplygina, V.; Zaidman, A.

    2011-01-01

    One of the key factors in customer satisfaction is application performance. To be able to guarantee good performance, it is necessary to take appropriate measures before a server overload occurs. While in small systems it is usually possible to predict server overload using a subjective human

  17. Maximizing performance in supercritical fluid chromatography using low-density mobile phases.

    Science.gov (United States)

    Gritti, Fabrice; Fogwill, Michael; Gilar, Martin; Jarrell, Joseph A

    2016-10-14

    The performance of a 3.0mm×150mm column packed with 1.8μm fully porous HSS-SB-C 18 particles was investigated in supercritical fluid chromatography (SFC) with low-density, highly expansible carbon dioxide. These conditions are selected for the analysis of semi-volatile compounds. Elevated temperatures (>100°C) were then combined with low column back pressures (<100bar). In this work, the inlet temperature of pure carbon dioxide was set at 107°C, the active back pressure regulator (ABPR) pressure was fixed at 100bar, and the flow rate was set at 2.1mL/min at 12°C (liquefied carbon dioxide) and at an inlet column pressure close to 300bar. Nine n-alkylbenzenes (from benzene to octadecylbenzene) were injected under linear (no sample overload) conditions. The severe steepness of the temperature gradients across the column diameter were predicted from a simplified heat transfer model. Such conditions dramatically lower the column performance by affecting the symmetry of the peak shape. In order to cope with this problem, three different approaches were experimentally tested. They include (1) the decoupling and the proper selection of the inlet eluent temperature with respect to the oven temperature, (2) the partial thermal insulation of the column using polyethylene aerogel, and (3) the application of a high vacuum (10 -5 Torr provided by a turbo-molecular pump) in a housing chamber surrounding the whole column body. The results reveal that (1) the column efficiency can be maximized by properly selecting the difference between the eluent and the oven temperatures, (2) the mere wrapping of the column with an excellent insulating material is insufficient to fully eliminate heat exchanges by conduction and the undesirable radial density gradients across the column i.d., and (3) the complete thermal insulation of the SFC column under high vacuum allows to maximize the column efficiency by maintaining the integrity of the peak shape. Copyright © 2016 Elsevier B.V. All

  18. Peripheral Venous Waveform Analysis for Detecting Hemorrhage and Iatrogenic Volume Overload in a Porcine Model.

    Science.gov (United States)

    Hocking, Kyle M; Sileshi, Ban; Baudenbacher, Franz J; Boyer, Richard B; Kohorst, Kelly L; Brophy, Colleen M; Eagle, Susan S

    2016-10-01

    Unrecognized hemorrhage and unguided resuscitation is associated with increased perioperative morbidity and mortality. The authors investigated peripheral venous waveform analysis (PIVA) as a method for quantitating hemorrhage as well as iatrogenic fluid overload during resuscitation. The authors conducted a prospective study on Yorkshire Pigs (n = 8) undergoing hemorrhage, autologous blood return, and administration of balanced crystalloid solution beyond euvolemia. Intra-arterial blood pressure, electrocardiogram, and pulse oximetry were applied to each subject. Peripheral venous pressure was measured continuously through an upper extremity standard peripheral IV catheter and analyzed with LabChart. The primary outcome was comparison of change in the first fundamental frequency (f1) of PIVA with standard and invasive monitoring and shock index (SI). Hemorrhage, return to euvolemia, and iatrogenic fluid overload resulted in significantly non-zero slopes of f1 amplitude. There were no significant differences in heart rate or mean arterial pressure, and a late change in SI. For the detection of hypovolemia the PIVA f1 amplitude change generated an receiver operator curves (ROC) curve with an area under the curve (AUC) of 0.93; heart rate AUC = 0.61; mean arterial pressure AUC = 0.48, and SI AUC = 0.72. For hypervolemia the f1 amplitude generated an ROC curve with an AUC of 0.85, heart rate AUC = 0.62, mean arterial pressure AUC = 0.63, and SI AUC = 0.65. In this study, PIVA demonstrated a greater sensitivity for detecting acute hemorrhage, return to euvolemia, and iatrogenic fluid overload compared with standard monitoring and SI. PIVA may provide a low-cost, minimally invasive monitoring solution for monitoring and resuscitating patients with perioperative hemorrhage.

  19. A new approach for primary overloads allowance in ratcheting evaluation

    International Nuclear Information System (INIS)

    Cabrillat, M.T.; Gatt, J.M.; Lejeail, Y.

    1995-01-01

    Seismic loading must be taken into account in ratchetting design analysis. In LMFBR structures it mainly produces primary overloads, which are characterised by severe magnitudes but a generally low number of occurrences. Other cases of several primary overloads can also observed in pipes during emptying operations for instance. In the RCC-MR design code rule, the maximum primary stress supported by a structure is considered as permanent. No allowance is made for temporary load. Experimental ratchetting tests conducted on different structures with and without overloads clearly point out that temporary overloads lead to less ratchetting effect. A method using the RCC-MR efficiency diagram framework is proposed. A general theoretical approach allows to extend its field of application of various cases of primary loading: constant or null primary loading or overloads. Experimental results are then used to check the validity of this new approach. (author). 2 refs., 2 figs., 2 tabs

  20. Effect of overloads on fatigue crack propagation rate

    International Nuclear Information System (INIS)

    Kogaev, V.P.; Bojtsov, B.V.; Petukhov, Yu.V

    1986-01-01

    An overload coefficient Q, the number of overload cycles Nsub(0), the value of the stress intensity coefficient swing of basic loading conditions ΔK are experimentally studied for their effect on the delay of the fatigue crack propagation Nsub(D) in 30KhGSNA steel. Results of the study are presented. It is shown that as a result of single overloads the value attains 60 - 10 thous. cycles. The delay Nsub(D) grows with the overload coefficient Q=Ksub(max)sup(0)/Ksub(max) and the number of the overload cycles Nsub(0). The regularity indicated is described by the equations valid within the limits of variation in Q and Nsub(0) values studied in the paper

  1. Iron overload and chelation therapy in myelodysplastic syndromes.

    Science.gov (United States)

    Temraz, Sally; Santini, Valeria; Musallam, Khaled; Taher, Ali

    2014-07-01

    Iron overload remains a concern in MDS patients especially those requiring recurrent blood transfusions. The consequence of iron overload may be more relevant in patients with low and intermediate-1 risk MDS who may survive long enough to experience such manifestations. It is a matter of debate whether this overload has time to yield organ damage, but it is quite evident that cellular damage and DNA genotoxic effect are induced. Iron overload may play a critical role in exacerbating pre-existing morbidity or even unmask silent ones. Under these circumstances, iron chelation therapy could play an integral role in the management of these patients. This review entails an in depth analysis of iron overload in MDS patients; its pathophysiology, effect on survival, associated risks and diagnostic options. It also discusses management options in relation to chelation therapy used in MDS patients and the impact it has on survival, hematologic response and organ function. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. OPTIMUM LEVEL OF POSITIVE END-EXPIRATORY PRESSURE IN ACUTE RESPIRATORY DISTRESS SYNDROME CAUSED BY INFLUENZA A(H1NI)PDM09: BALANCE BETWEEN MAXIMAL END-EXPIRATORY VOLUME AND MINIMAL ALVEOLAR OVERDISTENSION.

    Science.gov (United States)

    Yaroshetskiym A I; Protsenko, D N; Boytsov, P V; Chentsov, V B; Nistratov, S L; Kudlyakov, O N; Solov'ev, V V; Banova, Zh I; Shkuratova, N V; Rezenov, N A; Gel'fand, B R

    2016-11-01

    to determine optimum level ofpositive end-expiratory pressure (PEEP) according to balance between maxi- mal end-expiratory lung volume (EEL V)(more than predicted) and minimal decrease in exhaled carbon dioxide volume (VCO) and then to develop the algorithm of gas exchange correction based on prognostic values of EEL K; alveolar recruitability, PA/FiO2, static compliance (C,,,) and VCO2. 27 mechanically ventilatedpatients with acute respiratory distress syndrome (ARDS) caused by influenza A (HINJ)pdm09 in Moscow Municipal Clinics ICU's from January to March 2016 were included in the trial. At the beginning of the study patients had the following characteristic: duration offlu symptoms 5 (3-10) days, p.0/FiO2 120 (70-50) mmHg. SOFA 7 (5-9), body mass index 30.1 (26.4-33.8) kg/m², static compliance of respiratory system 35 (30-40) ml/mbar: Under sedation and paralysis we measured EELV, C VCO and end-tidal carbon dioxide concentration (EtCO) (for CO₂ measurements we fixed short-term values after 2 min after PEEP level change) at PEEP 8, 11,13,15,18, 20 mbar consequently, and incase of good recruitability, at 22 and 24 mbar. After analyses of obtained data we determined PEEP value in which increase in EELV was maximal (more than predicted) and depression of VCO₂ was less than 20%, change in mean blood pressure and heart rate were both less than 20% (measured at PEEP 8 mbar). After that we set thus determined level of PEEP and didn't change it for 5 days. Comparision of predicted and measured EELV revealed two typical points of alveloar recruiment: the first at PEEP 11-15 mbar, the second at PEEP 20-22 mbar. EELV measured at PEEP 18 mbar appeared to be higher than predicted at PEEP 8 mbar by 400 ml (approx.), which was the sign of alveolar recruitment-1536 (1020-1845) ml vs 1955 (1360-2320) ml, p=0,001, Friedman test). we didn't found significant changes of VCO₂ when increased PEEP in the range from 8 to 15 mbar (p>0.05, Friedman test). PEEP increase from 15 to

  3. Maximal Bell's inequality violation for non-maximal entanglement

    International Nuclear Information System (INIS)

    Kobayashi, M.; Khanna, F.; Mann, A.; Revzen, M.; Santana, A.

    2004-01-01

    Bell's inequality violation (BIQV) for correlations of polarization is studied for a product state of two two-mode squeezed vacuum (TMSV) states. The violation allowed is shown to attain its maximal limit for all values of the squeezing parameter, ζ. We show via an explicit example that a state whose entanglement is not maximal allow maximal BIQV. The Wigner function of the state is non-negative and the average value of either polarization is nil

  4. Evaluation of thermal overload in boiler operators.

    Science.gov (United States)

    Braga, Camila Soares; Rodrigues, Valéria Antônia Justino; Campos, Julio César Costa; de Souza, Amaury Paulo; Minette, Luciano José; de Moraes, Angêlo Casali; Sensato, Guilherme Luciano

    2012-01-01

    The Brazilians educational institutions need a large energy demand for the operation of laundries, restaurants and accommodation of students. Much of that energy comes from steam generated in boilers with wood fuel. The laboral activity in boiler may present problems for the operator's health due to exposure to excessive heat, and its operation has a high degree of risk. This paper describes an analysis made the conditions of thermal environment in the operation of a B category boiler, located at a Higher Education Institution, located in the Zona da Mata Mineira The equipments used to collect data were Meter WBGT of the Heat Index; Meter of Wet Bulb Index and Globe Thermometer (WBGT); Politeste Instruments, an anemometer and an Infrared Thermometer. By the application of questionnaires, the second phase consisted of collecting data on environmental factors (temperature natural environment, globe temperature, relative humidity and air velocity). The study concluded that during the period evaluated, the activity had thermal overload.

  5. Maximally Symmetric Composite Higgs Models.

    Science.gov (United States)

    Csáki, Csaba; Ma, Teng; Shu, Jing

    2017-09-29

    Maximal symmetry is a novel tool for composite pseudo Goldstone boson Higgs models: it is a remnant of an enhanced global symmetry of the composite fermion sector involving a twisting with the Higgs field. Maximal symmetry has far-reaching consequences: it ensures that the Higgs potential is finite and fully calculable, and also minimizes the tuning. We present a detailed analysis of the maximally symmetric SO(5)/SO(4) model and comment on its observational consequences.

  6. Design of overload vehicle monitoring and response system based on DSP

    Science.gov (United States)

    Yu, Yan; Liu, Yiheng; Zhao, Xuefeng

    2014-03-01

    The overload vehicles are making much more damage to the road surface than the regular ones. Many roads and bridges are equipped with structural health monitoring system (SHM) to provide early-warning to these damage and evaluate the safety of road and bridge. However, because of the complex nature of SHM system, it's expensive to manufacture, difficult to install and not well-suited for the regular bridges and roads. Based on this application background, this paper designs a compact structural health monitoring system based on DSP, which is highly integrated, low-power, easy to install and inexpensive to manufacture. The designed system is made up of sensor arrays, the charge amplifier module, the DSP processing unit, the alarm system for overload, and the estimate for damage of the road and bridge structure. The signals coming from sensor arrays go through the charge amplifier. DSP processing unit will receive the amplified signals, estimate whether it is an overload signal or not, and convert analog variables into digital ones so that they are compatible with the back-end digital circuit for further processing. The system will also restrict certain vehicles that are overweight, by taking image of the car brand, sending the alarm, and transferring the collected pressure data to remote data center for further monitoring analysis by rain-flow counting method.

  7. Principles of maximally classical and maximally realistic quantum ...

    Indian Academy of Sciences (India)

    Principles of maximally classical and maximally realistic quantum mechanics. S M ROY. Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India. Abstract. Recently Auberson, Mahoux, Roy and Singh have proved a long standing conjecture of Roy and Singh: In 2N-dimensional phase space, ...

  8. Stress, work overload, burnout, and satisfaction among paramedics in Israel.

    Science.gov (United States)

    Nirel, Nurit; Goldwag, Rachel; Feigenberg, Zvi; Abadi, David; Halpern, Pinchas

    2008-01-01

    The number of paramedics in Israel is increasing. Despite this growth and important role, the emergency medical organizations lack information about the characteristics of their work. The objective of this study was to examine the characteristics of the paramedics' work, the quality of their working lives, the factors that keep them in the profession, or conversely, draw them away from it. Cross-sectional study conducted through telephone interviews of a random sample of 50% of the graduates of paramedic courses in Israel (excluding conscripted soldiers). The factors that attract paramedics to the profession have much to do with the essence of the job-rescuing and saving-and a love of what it involves, as well as interest and variety. Pressures at work result from having to cope with a lack of administrative support, paperwork, long hours, imbalance between work and family life, and salary. They do not come from having to cope with responsibility, the pressure of working under uncertain conditions, and the sudden transition from calm situations to emergencies. Dissatisfaction at work is caused by burnout, work overload, and poor health. Physical and mental health that impedes their ability to work is related to a sense of burnout and the intention to change professions. The findings about the relationships between health, job satisfaction, and burnout, coupled with the fact that within a decade, half of the currently employed paramedics will reach an age at which it is hard for them to perform their job, lead to the conclusion that there is a need to reconsider the optimum length of service in the profession. There also is a need to form organizational arrangements to change the work procedures of aging paramedics.

  9. Refined reservoir description to maximize oil recovery

    International Nuclear Information System (INIS)

    Flewitt, W.E.

    1975-01-01

    To assure maximized oil recovery from older pools, reservoir description has been advanced by fully integrating original open-hole logs and the recently introduced interpretive techniques made available through cased-hole wireline saturation logs. A refined reservoir description utilizing normalized original wireline porosity logs has been completed in the Judy Creek Beaverhill Lake ''A'' Pool, a reefal carbonate pool with current potential productivity of 100,000 BOPD and 188 active wells. Continuous porosity was documented within a reef rim and cap while discontinuous porous lenses characterized an interior lagoon. With the use of pulsed neutron logs and production data a separate water front and pressure response was recognized within discrete environmental units. The refined reservoir description aided in reservoir simulation model studies and quantifying pool performance. A pattern water flood has now replaced the original peripheral bottom water drive to maximize oil recovery

  10. Dietary iron rural blacks overload In southern African

    African Journals Online (AJOL)

    1990-09-15

    Sep 15, 1990 ... suggest that iron overload from any cause may predispose to infection7 and there are .... consumption and acute inflammatory diseases. However, it ..... Addison GM, Beamish MR, Hales C ',Hodgkins M, Jacobs A, Llewellin P.

  11. VOLUME OVERLOAD IS ASSOCIATED WITH MALNUTRITION IN PERITONEAL DIALYSIS

    Directory of Open Access Journals (Sweden)

    Jin Joo Cha

    2012-06-01

    Volume overload is associated with malnutrition and seems to be an independent predictor of mortality in PD population. Further study should evaluate the effects of intervention of volume control in PD patients.

  12. Fatigue crack growth due to overloads in plain concrete using ...

    Indian Academy of Sciences (India)

    cation of overload on concrete structures, acceleration in the crack growth process .... study by the same authors, Ray & Chandra Kishen (2010), they have employed the population growth ...... Institute of Technology, University of Trondheim.

  13. Iron overload: what is the role of public health?

    Science.gov (United States)

    Hulihan, Mary M; Sayers, Cindy A; Grosse, Scott D; Garrison, Cheryl; Grant, Althea M

    2011-12-01

    Hereditary hemochromatosis type 1, also known as hereditary hemochromatosis classical (HHC), is an iron overload disorder associated, in most cases, with mutations of the hemochromatosis (HFE) gene. Although suggested algorithms for diagnosing iron overload are available, there are still questions about options for genetic and biochemical screening for hemochromatosis and duration of treatment. This article provides a summary of an expert workgroup meeting convened on September 24-25, 2009, entitled "Iron Overload: What is the Role of Public Health?" The purpose of the meeting was to enable subject matter experts to share their most recent clinical and scientific iron overload information and to facilitate the discussion of future endeavors, with special emphasis on the role of public health in this field. The two main topics were the research priorities of the field, including clinical, genetic, and public health issues, and the concerns about the validity of current screening recommendations for the condition. Published by Elsevier Inc.

  14. Network overload due to massive attacks

    Science.gov (United States)

    Kornbluth, Yosef; Barach, Gilad; Tuchman, Yaakov; Kadish, Benjamin; Cwilich, Gabriel; Buldyrev, Sergey V.

    2018-05-01

    We study the cascading failure of networks due to overload, using the betweenness centrality of a node as the measure of its load following the Motter and Lai model. We study the fraction of survived nodes at the end of the cascade pf as a function of the strength of the initial attack, measured by the fraction of nodes p that survive the initial attack for different values of tolerance α in random regular and Erdös-Renyi graphs. We find the existence of a first-order phase-transition line pt(α ) on a p -α plane, such that if p pt , pf is large and the giant component of the network is still present. Exactly at pt, the function pf(p ) undergoes a first-order discontinuity. We find that the line pt(α ) ends at a critical point (pc,αc) , in which the cascading failures are replaced by a second-order percolation transition. We find analytically the average betweenness of nodes with different degrees before and after the initial attack, we investigate their roles in the cascading failures, and we find a lower bound for pt(α ) . We also study the difference between localized and random attacks.

  15. Overloaded CDMA Systems with Displaced Binary Signatures

    Directory of Open Access Journals (Sweden)

    Vanhaverbeke Frederik

    2004-01-01

    Full Text Available We extend three types of overloaded CDMA systems, by displacing in time the binary signature sequences of these systems: (1 random spreading (PN, (2 multiple-OCDMA (MO, and (3 PN/OCDMA (PN/O. For each of these systems, we determine the time shifts that minimize the overall multiuser interference power. The achievable channel load with coded and uncoded data is evaluated for the conventional (without displacement and improved (with displacement systems, as well as for systems based on quasi-Welch-bound-equality (QWBE sequences, by means of several types of turbo detectors. For each system, the best performing turbo detector is selected in order to compare the performance of these systems. It is found that the improved systems substantially outperform their original counterparts. With uncoded data, (improved PN/O yields the highest acceptable channel load. For coded data, MO allows for the highest acceptable channel load over all considered systems, both for the conventional and the improved systems. In the latter case, channel loads of about 280% are achievable with a low degradation as compared to a single user system.

  16. Maximizing and customer loyalty: Are maximizers less loyal?

    Directory of Open Access Journals (Sweden)

    Linda Lai

    2011-06-01

    Full Text Available Despite their efforts to choose the best of all available solutions, maximizers seem to be more inclined than satisficers to regret their choices and to experience post-decisional dissonance. Maximizers may therefore be expected to change their decisions more frequently and hence exhibit lower customer loyalty to providers of products and services compared to satisficers. Findings from the study reported here (N = 1978 support this prediction. Maximizers reported significantly higher intentions to switch to another service provider (television provider than satisficers. Maximizers' intentions to switch appear to be intensified and mediated by higher proneness to regret, increased desire to discuss relevant choices with others, higher levels of perceived knowledge of alternatives, and higher ego involvement in the end product, compared to satisficers. Opportunities for future research are suggested.

  17. Implications of maximal Jarlskog invariant and maximal CP violation

    International Nuclear Information System (INIS)

    Rodriguez-Jauregui, E.; Universidad Nacional Autonoma de Mexico

    2001-04-01

    We argue here why CP violating phase Φ in the quark mixing matrix is maximal, that is, Φ=90 . In the Standard Model CP violation is related to the Jarlskog invariant J, which can be obtained from non commuting Hermitian mass matrices. In this article we derive the conditions to have Hermitian mass matrices which give maximal Jarlskog invariant J and maximal CP violating phase Φ. We find that all squared moduli of the quark mixing elements have a singular point when the CP violation phase Φ takes the value Φ=90 . This special feature of the Jarlskog invariant J and the quark mixing matrix is a clear and precise indication that CP violating Phase Φ is maximal in order to let nature treat democratically all of the quark mixing matrix moduli. (orig.)

  18. Myelodysplastic syndromes and the role of iron overload.

    Science.gov (United States)

    Harvey, R Donald

    2010-04-01

    The epidemiology of myelodysplastic syndromes (MDS) and iron overload, recent clinical findings that highlight the importance of actively managing iron overload, and recommendations for initiating and maintaining iron chelation therapy (ICT) are summarized. MDS are a variety of hematological disorders with differing time courses. Disease morbidities are primarily due to cytopenias and evolution to acute myeloid leukemia. Iron overload is a serious complication in patients with MDS due to the long-term use of red blood cell transfusions in patients with symptomatic anemia. Clinical consequences of iron overload include end-organ damage and dysfunction, an increased frequency of transplant-related complications, and reduced survival rates. To prevent these complications, recommendations for initiating and maintaining ICT should be followed by clinicians caring for patients with MDS and iron overload. As current therapeutic options for patients with MDS do not always reduce the transfusion burden, many patients will still need long-term transfusion therapy. Strategies for the management of iron overload in MDS should be considered early in the disease course and in appropriate patients in order to prevent negative clinical outcomes associated with excessive iron accumulation.

  19. Application of Chaos Theory in Trucks' Overloading Enforcement

    Directory of Open Access Journals (Sweden)

    Abbas Mahmoudabadi

    2013-01-01

    Full Text Available Trucks' overloading is considered as one of the most substantial concerns in road transport due to a possible road surface damage, as well as, are less reliable performance of trucks' braking system. Sufficient human resource and adequate time scheduling are to be planned for surveying trucks' overloading; hence, it seems required to prepare an all-around model to be able to predict the number of overloaded vehicles. In the present research work, the concept of chaos theory has been utilized to predict the ratio of trucks which might be guessed overloaded. The largest Lyapunov exponent is utilized to determine the presence of chaos using experimental data and concluded that the ratio of overloaded trucks reflects chaotic behavior. The prediction based on chaos theory is compared with the results of simple smoothing and moving average methods according to the well-known criterion of mean square errors. The results have also revealed that the chaotic prediction model would act more capably comparing the analogous methods including simple smoothing and moving average to predict the ratio of passing trucks to be possibly overloaded.

  20. Research progress in role of iron overload in non-alcoholic fatty liver disease

    OpenAIRE

    LI Guangming

    2013-01-01

    Iron overload is an important research focus in non-alcoholic fatty liver disease (NAFLD). The relationship between iron overload and NAFLD is summarized from the assessment method for iron overload, relationship between iron load and hemochromatosis gene mutations, incidence of iron load in NAFLD, and relationship between iron load and progression of NAFLD; the action mechanism of iron overload in the progression of NAFLD is reviewed from the causes of iron overload, relationship between iro...

  1. Phenomenology of maximal and near-maximal lepton mixing

    International Nuclear Information System (INIS)

    Gonzalez-Garcia, M. C.; Pena-Garay, Carlos; Nir, Yosef; Smirnov, Alexei Yu.

    2001-01-01

    The possible existence of maximal or near-maximal lepton mixing constitutes an intriguing challenge for fundamental theories of flavor. We study the phenomenological consequences of maximal and near-maximal mixing of the electron neutrino with other (x=tau and/or muon) neutrinos. We describe the deviations from maximal mixing in terms of a parameter ε(equivalent to)1-2sin 2 θ ex and quantify the present experimental status for |ε| e mixing comes from solar neutrino experiments. We find that the global analysis of solar neutrino data allows maximal mixing with confidence level better than 99% for 10 -8 eV 2 ∼ 2 ∼ -7 eV 2 . In the mass ranges Δm 2 ∼>1.5x10 -5 eV 2 and 4x10 -10 eV 2 ∼ 2 ∼ -7 eV 2 the full interval |ε| e mixing in atmospheric neutrinos, supernova neutrinos, and neutrinoless double beta decay

  2. Maximal quantum Fisher information matrix

    International Nuclear Information System (INIS)

    Chen, Yu; Yuan, Haidong

    2017-01-01

    We study the existence of the maximal quantum Fisher information matrix in the multi-parameter quantum estimation, which bounds the ultimate precision limit. We show that when the maximal quantum Fisher information matrix exists, it can be directly obtained from the underlying dynamics. Examples are then provided to demonstrate the usefulness of the maximal quantum Fisher information matrix by deriving various trade-off relations in multi-parameter quantum estimation and obtaining the bounds for the scalings of the precision limit. (paper)

  3. Maximize x(a - x)

    Science.gov (United States)

    Lange, L. H.

    1974-01-01

    Five different methods for determining the maximizing condition for x(a - x) are presented. Included is the ancient Greek version and a method attributed to Fermat. None of the proofs use calculus. (LS)

  4. Finding Maximal Quasiperiodicities in Strings

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Pedersen, Christian N. S.

    2000-01-01

    of length n in time O(n log n) and space O(n). Our algorithm uses the suffix tree as the fundamental data structure combined with efficient methods for merging and performing multiple searches in search trees. Besides finding all maximal quasiperiodic substrings, our algorithm also marks the nodes......Apostolico and Ehrenfeucht defined the notion of a maximal quasiperiodic substring and gave an algorithm that finds all maximal quasiperiodic substrings in a string of length n in time O(n log2 n). In this paper we give an algorithm that finds all maximal quasiperiodic substrings in a string...... in the suffix tree that have a superprimitive path-label....

  5. On the maximal diphoton width

    CERN Document Server

    Salvio, Alberto; Strumia, Alessandro; Urbano, Alfredo

    2016-01-01

    Motivated by the 750 GeV diphoton excess found at LHC, we compute the maximal width into $\\gamma\\gamma$ that a neutral scalar can acquire through a loop of charged fermions or scalars as function of the maximal scale at which the theory holds, taking into account vacuum (meta)stability bounds. We show how an extra gauge symmetry can qualitatively weaken such bounds, and explore collider probes and connections with Dark Matter.

  6. Aldosterone and mortality in hemodialysis patients: role of volume overload.

    Science.gov (United States)

    Hung, Szu-Chun; Lin, Yao-Ping; Huang, Hsin-Lei; Pu, Hsiao-Fung; Tarng, Der-Cherng

    2013-01-01

    Elevated aldosterone is associated with increased mortality in the general population. In patients on dialysis, however, the association is reversed. This paradox may be explained by volume overload, which is associated with lower aldosterone and higher mortality. We evaluated the relationship between aldosterone and outcomes in a prospective cohort of 328 hemodialysis patients stratified by the presence or absence of volume overload (defined as extracellular water/total body water >48%, as measured with bioimpedance). Baseline plasma aldosterone was measured before dialysis and categorized as low (280 pg/mL). Overall, 36% (n = 119) of the hemodialysis patients had evidence of volume overload. Baseline aldosterone was significantly lower in the presence of volume overload than in its absence. During a median follow-up of 54 months, 83 deaths and 70 cardiovascular events occurred. Cox multivariate analysis showed that by using the low aldosterone as the reference, high aldosterone was inversely associated with decreased hazard ratios for mortality (0.49; 95% confidence interval, 0.25-0.76) and first cardiovascular event (0.70; 95% confidence interval, 0.33-0.78) in the presence of volume overload. In contrast, high aldosterone was associated with an increased risk for mortality (1.97; 95% confidence interval, 1.69-3.75) and first cardiovascular event (2.01; 95% confidence interval, 1.28-4.15) in the absence of volume overload. The inverse association of aldosterone with adverse outcomes in hemodialysis patients is due to the confounding effect of volume overload. These findings support treatment of hyperaldosteronemia in hemodialysis patients who have achieved strict volume control.

  7. Cardiorespiratory Coordination in Repeated Maximal Exercise

    Directory of Open Access Journals (Sweden)

    Sergi Garcia-Retortillo

    2017-06-01

    Full Text Available Increases in cardiorespiratory coordination (CRC after training with no differences in performance and physiological variables have recently been reported using a principal component analysis approach. However, no research has yet evaluated the short-term effects of exercise on CRC. The aim of this study was to delineate the behavior of CRC under different physiological initial conditions produced by repeated maximal exercises. Fifteen participants performed 2 consecutive graded and maximal cycling tests. Test 1 was performed without any previous exercise, and Test 2 6 min after Test 1. Both tests started at 0 W and the workload was increased by 25 W/min in males and 20 W/min in females, until they were not able to maintain the prescribed cycling frequency of 70 rpm for more than 5 consecutive seconds. A principal component (PC analysis of selected cardiovascular and cardiorespiratory variables (expired fraction of O2, expired fraction of CO2, ventilation, systolic blood pressure, diastolic blood pressure, and heart rate was performed to evaluate the CRC defined by the number of PCs in both tests. In order to quantify the degree of coordination, the information entropy was calculated and the eigenvalues of the first PC (PC1 were compared between tests. Although no significant differences were found between the tests with respect to the performed maximal workload (Wmax, maximal oxygen consumption (VO2 max, or ventilatory threshold (VT, an increase in the number of PCs and/or a decrease of eigenvalues of PC1 (t = 2.95; p = 0.01; d = 1.08 was found in Test 2 compared to Test 1. Moreover, entropy was significantly higher (Z = 2.33; p = 0.02; d = 1.43 in the last test. In conclusion, despite the fact that no significant differences were observed in the conventionally explored maximal performance and physiological variables (Wmax, VO2 max, and VT between tests, a reduction of CRC was observed in Test 2. These results emphasize the interest of CRC

  8. Assessment of right ventricular overload using 99mTc-hexakis-methoxy-2-isobutylisonitrile (MIBI) and 123I-β-methyl iodophenyl pentadecanoic acid (BMIPP) myocardial scintigraphy

    International Nuclear Information System (INIS)

    Matsumoto, Katsushige

    2002-01-01

    Thallium-201 myocardial imaging is known to be useful for evaluating right ventricular (RV) overload. The degree of RV wall visualization has been shown to reflect RV myocardial mass and the right-to-left ventricular pressure ratio. Recently, 99m Tc-hexakis-methoxy-2-isobutylisonitrile (MIBI) and 123 I-β-methyl iodophenyl pentadecanoic acid (BMIPP) were developed and have been used to evaluate ischemic heart disease. The purpose of this study was to evaluate the RV pressure and myocardial fatty acid metabolism in the right ventricle in patients with chronic RV overloading using 99m Tc-MIBI and 123 I-BMIPP myocardial imaging. 99m Tc-MIBI myocardial scintigraphy (planar and SPECT) was performed in 76 patients with RV overloading, and 123 I-BMIPP SPECT was performed in 33 patients with RV overloading. The degree of RV wall visualization using 99m Tc-MIBI planar imaging was correlated with the elevation of RV systolic pressure. The right atrium was visualized with a high frequency in patients with RV overloading, and the degree of the right atrial wall visualization was correlated with the elevation of RV end-diastolic pressure. A count ratio of right-to-left ventricular free wall (RV/LV ratio) using 99m Tc-MIBI SPECT correlated well with a systolic pressure ratio of right-to-left ventricle (sRVp/sLVp). On the other hand, no significant correlation was found between RV/LV ratio using 123 I-BMIPP SPECT and sRVp/sLVp. For the patients with RV overloading at a RV systolic pressure of 70 mmHg or more, impaired fatty acid metabolism in the RV myocardium was noted using the quantitative analysis of 123 I-BMIPP SPECT. In conclusion, RV pressure can be evaluated by quantitative analysis using 99m Tc-MIBI myocardial scintigraphy. Myocardial metabolism in the RV wall may be impaired in patients with severe RV overloading. (author)

  9. The role of fluid overload in the prediction of outcome in acute kidney injury.

    Science.gov (United States)

    Selewski, David T; Goldstein, Stuart L

    2018-01-01

    Our understanding of the epidemiology and the impact of acute kidney injury (AKI) and fluid overload on outcomes has improved significantly over the past several decades. Fluid overload occurs commonly in critically ill children with and without associated AKI. Researchers in pediatric AKI have been at the forefront of describing the impact of fluid overload on outcomes in a variety of populations. A full understanding of this topic is important as fluid overload represents a potentially modifiable risk factor and a target for intervention. In this state-of-the-art review, we comprehensively describe the definition of fluid overload, the impact of fluid overload on kidney function, the impact of fluid overload on the diagnosis of AKI, the association of fluid overload with outcomes, the targeted therapy of fluid overload, and the impact of the timing of renal replacement therapy on outcomes.

  10. Maximizing Lumen Gain With Directional Atherectomy.

    Science.gov (United States)

    Stanley, Gregory A; Winscott, John G

    2016-08-01

    To describe the use of a low-pressure balloon inflation (LPBI) technique to delineate intraluminal plaque and guide directional atherectomy in order to maximize lumen gain and achieve procedure success. The technique is illustrated in a 77-year-old man with claudication who underwent superficial femoral artery revascularization using a HawkOne directional atherectomy catheter. A standard angioplasty balloon was inflated to 1 to 2 atm during live fluoroscopy to create a 3-dimensional "lumenogram" of the target lesion. Directional atherectomy was performed only where plaque impinged on the balloon at a specific fluoroscopic orientation. The results of the LPBI technique were corroborated with multimodality diagnostic imaging, including digital subtraction angiography, intravascular ultrasound, and intra-arterial pressure measurements. With the LPBI technique, directional atherectomy can routinely achieve <10% residual stenosis, as illustrated in this case, thereby broadly supporting a no-stent approach to lower extremity endovascular revascularization. © The Author(s) 2016.

  11. Maximization

    Directory of Open Access Journals (Sweden)

    A. Garmroodi Asil

    2017-09-01

    To further reduce the sulfur dioxide emission of the entire refining process, two scenarios of acid gas or air preheats are investigated when either of them is used simultaneously with the third enrichment scheme. The maximum overall sulfur recovery efficiency and highest combustion chamber temperature is slightly higher for acid gas preheats but air preheat is more favorable because it is more benign. To the best of our knowledge, optimization of the entire GTU + enrichment section and SRU processes has not been addressed previously.

  12. Mechanism Research of Arch Dam Abutment Forces during Overload

    Directory of Open Access Journals (Sweden)

    Yu Xia

    2015-01-01

    Full Text Available This paper presents research on the abutment forces of a double-curvature arch dam during overload based on numerical calculation results obtained through finite element method by Ansys. Results show that, with an increase in elevation, the abutment forces and bending moment of the arch dam increase first and then decrease from the bottom to the top of the dam. Abutment forces and bending moment reach their maximum at the middle or middle-down portion of the dam. The distributions of abutment forces and moment do not change during overload. The magnitude of each arch layer’s forces and moment increases linearly during overload. This result indicates that each arch layer transmits bearing loads to the rocks of the left and right banks steadily. This research explains the operating mechanism of an arch dam under normal and overload conditions. It provides a simple method to calculate the distribution of forces Fx and Fy and a new method to calculate the overload factor of an arch dam through the estimation of arch layers based on the redistribution characteristic of arch abutment forces.

  13. Isometric handgrip does not elicit cardiovascular overload or post-exercise hypotension in hypertensive older women

    Directory of Open Access Journals (Sweden)

    Olher RR

    2013-06-01

    Full Text Available Rafael dos Reis Vieira Olher,1,2,* Danilo Sales Bocalini,3,* Reury Frank Bacurau,4 Daniel Rodriguez,5 Aylton Figueira Jr,5 Francisco Luciano Pontes Jr,4 Francisco Navarro,6 Herbert Gustavo Simões,1 Ronaldo Carvalho Araujo,7 Milton Rocha Moraes8 1Universidade Católica de Brasília, Distrito Federal, 2Universidade Gama Filho, Rio de Janeiro, 3Universidade Nove de Julho (UNINOVE, São Paulo, 4Universidade de São Paulo – Escola de Artes, Ciências e Humanidades, São Paulo, 5Universidade São Judas Tadeu (USJT, São Paulo, Brazil, 6Universidade Federal do Maranhão, Maranhão, 7Universidade de São Paulo, Instituto de Ciências Biomédicas, São Paulo, 8Universidade Federal de São Paulo – Escola Paulista de Medicina, São Paulo, Brazil *These authors contributed equally to this work Background: Arterial hypertension is a serious health problem affecting mainly the elderly population. Recent studies have considered both aerobic and resistance exercises as a non-pharmacological aid for arterial hypertension treatment. However, the cardiovascular responses of the elderly to isometric resistance exercise (eg, isometric handgrip [IHG] have not yet been documented. Objective: The purpose of this study was to investigate cardiovascular responses to different intensities of isometric exercise, as well as the occurrence of post-isometric exercise hypotension in hypertensive elderly people under antihypertensive medication treatment. Patients and methods: Twelve women volunteered to participate in the study after a maximal voluntary contraction test (MVC and standardization of the intervention workload consisting of two sessions of IHG exercise performed in four sets of five contractions of a 10-second duration. Sessions were performed both at 30% of the MVC and 50% of the MVC, using a unilateral IHG protocol. Both intensities were compared with a control session without exercise. Systolic blood pressure (SBP and diastolic blood pressure (DBP at rest

  14. Maximizing Entropy over Markov Processes

    DEFF Research Database (Denmark)

    Biondi, Fabrizio; Legay, Axel; Nielsen, Bo Friis

    2013-01-01

    The channel capacity of a deterministic system with confidential data is an upper bound on the amount of bits of data an attacker can learn from the system. We encode all possible attacks to a system using a probabilistic specification, an Interval Markov Chain. Then the channel capacity...... as a reward function, a polynomial algorithm to verify the existence of an system maximizing entropy among those respecting a specification, a procedure for the maximization of reward functions over Interval Markov Chains and its application to synthesize an implementation maximizing entropy. We show how...... to use Interval Markov Chains to model abstractions of deterministic systems with confidential data, and use the above results to compute their channel capacity. These results are a foundation for ongoing work on computing channel capacity for abstractions of programs derived from code....

  15. Maximizing entropy over Markov processes

    DEFF Research Database (Denmark)

    Biondi, Fabrizio; Legay, Axel; Nielsen, Bo Friis

    2014-01-01

    The channel capacity of a deterministic system with confidential data is an upper bound on the amount of bits of data an attacker can learn from the system. We encode all possible attacks to a system using a probabilistic specification, an Interval Markov Chain. Then the channel capacity...... as a reward function, a polynomial algorithm to verify the existence of a system maximizing entropy among those respecting a specification, a procedure for the maximization of reward functions over Interval Markov Chains and its application to synthesize an implementation maximizing entropy. We show how...... to use Interval Markov Chains to model abstractions of deterministic systems with confidential data, and use the above results to compute their channel capacity. These results are a foundation for ongoing work on computing channel capacity for abstractions of programs derived from code. © 2014 Elsevier...

  16. Symmetrical and overloaded effect of diffusion in information filtering

    Science.gov (United States)

    Zhu, Xuzhen; Tian, Hui; Chen, Guilin; Cai, Shimin

    2017-10-01

    In physical dynamics, mass diffusion theory has been applied to design effective information filtering models on bipartite network. In previous works, researchers unilaterally believe objects' similarities are determined by single directional mass diffusion from the collected object to the uncollected, meanwhile, inadvertently ignore adverse influence of diffusion overload. It in some extent veils the essence of diffusion in physical dynamics and hurts the recommendation accuracy and diversity. After delicate investigation, we argue that symmetrical diffusion effectively discloses essence of mass diffusion, and high diffusion overload should be published. Accordingly, in this paper, we propose an symmetrical and overload penalized diffusion based model (SOPD), which shows excellent performances in extensive experiments on benchmark datasets Movielens and Netflix.

  17. Testing of camera performance standards at steady and local overloading

    International Nuclear Information System (INIS)

    Keszthelyine Landori, S.; Adorjanne Farkas, M.; Csirik, J.

    1983-01-01

    Camera performance standards are usually given for low count rates and uniform irradiation. A conventional analog gamma camera system (Gamma MB 9100 manufactured under the know-how of Picker DC 4/12 in Hungary) was studied on the basis of the Picker test procedure and the NEMA standard system. Uniformity, linearity, spatial and energy resolution were measured at high count rates and uniform irradiation (steady overloading). Linearity was studied at local overloading. Linearity, spatial and energy resolution were measured by a 1024-channel analyzer-computer system of KFKI, Hungary. The data were evaluated on the basis of NEMA standards, while uniformity was measured by the Gamma data processing system and evaluated by special SEGAMS programs. Performance variations were studied between 7500 cps and 75.000 cps pulse rates. Spatial and energy resolution were influenced strongly, uniformity slightly by pulse rates, while linearity did not change at all. Linearity was not influenced even by local overloading. (author)

  18. Overloaded and stressed: A case study of women working in the health care sector.

    Science.gov (United States)

    Stevenson, Maggie; Duxbury, Linda

    2018-04-23

    Although role overload has been shown to be prevalent and consequential, there has been little attempt to develop the associated theory. The fact that the consequences of role overload can be positive or negative implies that the relationship between role overload and perceived stress depends partly on the environment within which role overload is experienced (i.e., the perceived situation) and how the situation is evaluated (i.e., appraised). Guided by cognitive appraisal theory, this study applies qualitative methodology to identify the situation properties that contribute to variable stress reactions to role overload. In this in-depth examination, overloaded female hospital workers were asked to describe what makes role overload situations potentially stressful, to gain an insight into how role overload is appraised. A taxonomy listing 12 role overload situation properties was developed from the findings, providing the first known classification of the situation properties of role overload that can create the potential for stress. The results also reveal clues as to why some people suffer more stress during role overload than others, increase our understanding of the relationship between role overload and perceived stress, and provide a useful tool for examining the environment of role overload. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  19. Overload Control in Smart Transformer-Fed Grid

    Directory of Open Access Journals (Sweden)

    Giovanni De Carne

    2017-02-01

    Full Text Available Renewable energy resources and new loads—such as electric vehicles—challenge grid management. Among several scenarios, the smart transformer represents a solution for simultaneously managing low- and medium-voltage grids, providing ancillary services to the distribution grid. However, unlike conventional transformers, the smart transformer has a very limited overload capability, because the junction temperature—which must always be below its maximum limit—is characterized by a short time constant. In this work, an overload control for smart transformer by means of voltage and frequency variations has been proposed and verified by means of simulations and experiments.

  20. Spreading the load: mobile information and communications technologies and their effect on information overload

    Directory of Open Access Journals (Sweden)

    D.K. Allan

    2005-01-01

    Full Text Available Introduction. We report on a small-scale research project which examined the impact of mobile technologies on the users' experience of information overload. The project focused on a group of worker who have had relatively little attention in both the mobile technology and information overload literatures: senior managers. Method. The case study approach was adopted, as complementary to an incremental approach to theory building. An inductive approach is adopted, in which data are collected and the findings are interpreted in the light of previous work. The case site was West Yorkshire Police Force in the UK where BlackBerry handhelds were being used by senior officers. Analysis. A semi-structured interview schedule was developed and applied in face-to-face interviews with the Senior Management Team and their secretaries. All interviews were recorded and the transcripts of the interviews analysed, using qualitative coding. Results. A conceptual model of the interactions and relationships among the key elements that drive and mediate the information flows and information behaviour within a complex organizational environment was developed. Managers' information behaviour and coping strategies were found to have changed since the introduction of mobile devices. Officers are more likely to deal with information received sooner, thereby resulting in less queuing of messages (although filtering strategies still prevail. Approximation (responding in a non-precise way was also found to have increased. In this particular implementation, the mobile technology has not altered the information-pull behaviour of managers. Conclusion. The main finding is that personal information management is now distributed more evenly throughout the day. Thus, the technology has enabled officers to 'spread the load' and, in doing so, has helped to ease some of the pressures created by information overload.

  1. Chamaebatiaria millefolium (Torr.) Maxim.: fernbush

    Science.gov (United States)

    Nancy L. Shaw; Emerenciana G. Hurd

    2008-01-01

    Fernbush - Chamaebatiaria millefolium (Torr.) Maxim. - the only species in its genus, is endemic to the Great Basin, Colorado Plateau, and adjacent areas of the western United States. It is an upright, generally multistemmed, sweetly aromatic shrub 0.3 to 2 m tall. Bark of young branches is brown and becomes smooth and gray with age. Leaves are leathery, alternate,...

  2. Ulnohumeral chondral and ligamentous overload: biomechanical correlation for posteromedial chondromalacia of the elbow in throwing athletes.

    Science.gov (United States)

    Osbahr, Daryl C; Dines, Joshua S; Breazeale, Nathan M; Deng, Xiang-Hua; Altchek, David W

    2010-12-01

    Previous studies have documented increased posteromedial contact forces with the elbow at lower flexion angles associated with valgus extension overload; however, the authors believe that posteromedial elbow impingement in association with valgus laxity is a complex pathological process that may occur throughout the entire throwing motion in the form of ulnohumeral chondral and ligamentous overload. Valgus laxity with the elbow at 90° of flexion may lead to chondromalacia secondary to a subtle shift in the contact point between the tip of the olecranon and the distal humeral trochlea. Controlled laboratory study. Six fresh human cadaveric elbows were dissected and subjected to a static valgus load. Pressure-sensitive Fuji film measured the contact pressure, contact area, and shift in contact area across the posteromedial elbow before and after sectioning the anterior bundle of the ulnar collateral ligament. The contact pressure between the tip of the olecranon process and the medial crista of the posterior humeral trochlea significantly increased, from an average of 0.27 ± 0.06 kg/cm² to 0.40 ± 0.08 kg/cm². The contact area also significantly decreased, from an average of 30.34 ± 9.17 mm² to 24.59 ± 6.44 mm², and shifted medially on the medial humeral crista, which corresponds to the position of the posteromedial chondral lesions that was observed in throwing athletes in the authors' clinical practice. While simulating the early acceleration phase of the throwing motion with the elbow in 90° of flexion, the results illustrate that abnormal contact may occur as a result of valgus laxity through increased contact pressures across the posteromedial elbow between the medial tip of the olecranon and medial crista of the humeral trochlea. In addition, congruency of the ulnohumeral joint changed, as there was a statistically significant medial shift of the olecranon on the posterior humeral trochlea with the elbow at 90° of flexion after sectioning the anterior

  3. Can We Ever Escape from Data Overload? A Cognitive Systems Diagnosis

    National Research Council Canada - National Science Library

    Woods, David

    1998-01-01

    Data overload is a generic and tremendously difficult problem. In this report, we diagnose why this is the case and how intelligence analysis presents a particularly difficult version of data overload...

  4. Magnetic and quadrupolar studies of the iron storage overload in livers

    International Nuclear Information System (INIS)

    Rimbert, J.N.; Dumas, F.; Richardot, G.; Kellershohn, C.

    1986-01-01

    Absorption 57 Fe Moessbauer spectra, performed directly on tissues of liver with iron overload due to an excessive intestinal iron absorption or induced by hypertransfusional therapeutics, have pointed out a new high spin ferric storage iron besides the ferritin and hemosiderin. Moessbauer studies, carried out on ferritin and hemosiderin fractions isolated from normal and overloaded livers, show that this compound, only present in the secondary iron overload (transfusional pathway), seems characteristic of the physiological process which induces the iron overload. (Auth.)

  5. Iron overload of organism and current options of chelation treatment in onco haematology

    International Nuclear Information System (INIS)

    Guman, T.; Rothova, E.; Kafkova, A.; Fricova, M.; Dulova, I.; Stecova, N.; Hlebaskova, M.; Surova, M.; Takac, V.

    2011-01-01

    The article summarizes the biological importance of iron in the organism, primary and secondary causes of iron overload, complications in function of liver, heart and endocrine organs due to overload of iron, the pathophysiology of iron overload, transfusion risks associated with the iron overload, assessment of risk groups of patients suitable for chelation treatment fulfilling the indication criteria, treatment modalities of chelation therapy and its significance regarding the prevention and treatment effectiveness. (author)

  6. Determination of Permissible Short-Time Emergency Overloading of Turbo-Generators and Synchronous Compensators

    Directory of Open Access Journals (Sweden)

    V. A. Anischenko

    2011-01-01

    Full Text Available The paper shows that failure to take into account variable ratio of short-time emergency overloading of turbo-generators (synchronous compensators that can lead to underestimation of overloading capacity or impermissible insulation over-heating.A method has been developed for determination of permissible duration of short-time emergency over-loading that takes into account changes of over-loading ratio in case of a failure.

  7. Iron deficiency and overload in relation to nutrition

    NARCIS (Netherlands)

    Spanjersberg MQI; Jansen EHJM; LEO

    2000-01-01

    Nutritional iron intake in the Netherlands has been reviewed with respect to both iron deficiency and iron overload. In general, iron intake and iron status in the Netherlands are adequate and therefore no change in nutrition policy is required. The following aspects and developments, however, need

  8. The association between role overload and women's mental health.

    Science.gov (United States)

    Glynn, Keva; Maclean, Heather; Forte, Tonia; Cohen, Marsha

    2009-02-01

    To determine the importance of role overload (the extent to which a person feels overwhelmed by her total responsibilities) relative to other known social determinants of women's mental health. A Canadian national, random sample, cross-sectional telephone survey in 2003 assessed the association among role overload, types and quality of roles (parent, employee, spouse), sociodemographics, and mental health (using the SF-12) using linear regression. Analysis included 716 women aged 25-54 who indicated that their youngest child living in the household was aged < or =17 years. Perceptions of greater role overload were associated with poorer mental health (p < 0.0001). Women working <35 hours per week (p = 0.04) or 35-40 hours per week (p 5 0.002) reported better mental health than nonemployed women, as did women with the highest annual household income ($70,000+)(p = 0.001). Also associated with better mental health were higher marital status quality scores for both married and single women (p < 0.001), higher job quality scores among employed women (p = 0.02), greater homemaking quality scores among unemployed women (p = 0.03), and women reporting high parental quality (p = 0.04) Role overload showed a stronger relationship to mental health than other sociodemographic variables, including income. Our findings indicate the importance of measuring women's experience of their multiple roles rather than focusing on single roles. More research is warranted on the totality of women's experiences of their many social role obligations.

  9. Glycolytic overload and the genesis of breast cancer.

    Science.gov (United States)

    Robson, J R

    1984-03-01

    It is suggested that the development of breast cancer is due to overloading of the glycolytic pathways. An excess of substrates or an excessive delivery rate of substrates to the Krebs Cycle is believed to result in the formation of acetyl CoA. Feedback mechanisms controlling the conversion of acetyl CoA to cholesterol may be overcome; the resulting high concentration of cholesterol induces the formation of pregnenolone which may then be converted into androgens, estrogens and progesterone. These steroids are in addition to those produced by gonads and adrenal glands. Glycolytic overload is also associated with an increase in fat stores which have been shown to be the site of interconversion of sex hormones. Excess sex hormones or abnormal sex hormones are believed to be the cause of breast cancer. The hypothesis presented links glycolytic overload with clinical biochemical phenomena and explains some of the anomalies observed in breast cancer experience in different ethnic groups. Changes in dietary habits during the history of man resulting in " gorging " and the consumption of highly refined sugars are possible causes of glycolytic overload. So, also, is impaired thermogenesis due to Brown Fat deficits in certain ethnic groups.

  10. Random fluid limit of an overloaded polling model

    NARCIS (Netherlands)

    M. Frolkova (Masha); S.G. Foss (Sergey); A.P. Zwart (Bert)

    2014-01-01

    htmlabstractIn the present paper, we study the evolution of an overloaded cyclic polling model that starts empty. Exploiting a connection with multitype branching processes, we derive fluid asymptotics for the joint queue length process. Under passage to the fluid dynamics, the server switches

  11. Random fluid limit of an overloaded polling model

    NARCIS (Netherlands)

    M. Frolkova (Masha); S.G. Foss (Sergey); A.P. Zwart (Bert)

    2013-01-01

    htmlabstractIn the present paper, we study the evolution of an~overloaded cyclic polling model that starts empty. Exploiting a~connection with multitype branching processes, we derive fluid asymptotics for the joint queue length process. Under passage to the fluid dynamics, the server switches

  12. Information Overload in Multi-Stage Selection Procedures

    NARCIS (Netherlands)

    S.S. Ficco (Stefano); V.A. Karamychev (Vladimir)

    2004-01-01

    textabstractThe paper studies information processing imperfections in a fully rational decision-making network. It is shown that imperfect information transmission and imperfect information acquisition in a multi-stage selection game yield information overload. The paper analyses the mechanisms

  13. Modeling of Unidirectional-Overloaded Transition in Catalytic Tubular Microjets

    NARCIS (Netherlands)

    Klingner, Anke; Khalil, Islam S. M.; Magdanz, Veronika; Fomin, Vladimir M.; Schmidt, Oliver G.; Misra, Sarthak

    2017-01-01

    A numerical time-resolved model is presented for predicting the transition between unidirectional and overloaded motion of catalytic tubular microjets (Ti/Fe/Pt rolled-up microtubes) in an aqueous solution of hydrogen peroxide. Unidirectional movement is achieved by periodic ejection of gas bubbles

  14. Fetal liver iron overload: the role of MR imaging

    International Nuclear Information System (INIS)

    Cassart, Marie; Avni, Freddy Efraim; Guibaud, Laurent; Molho, Marc; D'Haene, Nicky; Paupe, Alain

    2011-01-01

    To assess the potential role of MR imaging in the diagnosis of fetal liver iron overload. We reviewed seven cases of abnormal liver signal in fetuses referred to MR imaging in a context of suspected congenital infection (n = 2), digestive tract anomalies (n = 3) and hydrops fetalis (n = 2). The average GA of the fetuses was 31 weeks. The antenatal diagnoses were compared with histological data (n = 6) and postnatal work-up (n = 1). Magnetic resonance imaging demonstrated unexpected abnormal fetal liver signal suggestive of iron overload in all cases. The iron overload was confirmed on postnatal biopsy (n = 2) and fetopathology (n = 4). The final diagnosis was hepatic hemosiderosis (haemolytic anaemia (n = 2) and syndromal anomalies (n = 2)) and congenital haemochromatosis (n = 3). In all cases, the liver appeared normal on US. Magnetic resonance is the only imaging technique able to demonstrate liver iron overload in utero. Yet, the study outlines the fundamental role of MR imaging in cases of congenital haemochromatosis. The antenatal diagnosis of such a condition may prompt ante - (in the case of recurrence) or neonatal treatment, which might improve the prognosis. (orig.)

  15. Tools to Reduce Overload in the School Social Worker Role

    Science.gov (United States)

    Leyba, Erin Gleason

    2009-01-01

    This article addresses how school social workers can decrease overload in their roles. A two-step process of envisioning an ideal role is outlined: (1) indentifying priorities and activities that are effective or in need of expansion and (2) weeding out activities that could be done differently or no longer serve their purpose. The author…

  16. Fetal liver iron overload: the role of MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Cassart, Marie; Avni, Freddy Efraim [Erasme Hospital, Medical imaging, Brussels, Brabant (Belgium); Guibaud, Laurent [Hopital femme mere enfant, Imagerie Pediatrique et Foetale, Lyon-Bron (France); Molho, Marc [C.H.I Poissy/St Germain-en-Laye, Imagerie Medicale, Poissy (France); D' Haene, Nicky [Erasme Hospital, Anatomopathology Department, Brussels (Belgium); Paupe, Alain [C.H.I Poissy/St Germain-en-Laye, Pediatrie, Poissy (France)

    2011-02-15

    To assess the potential role of MR imaging in the diagnosis of fetal liver iron overload. We reviewed seven cases of abnormal liver signal in fetuses referred to MR imaging in a context of suspected congenital infection (n = 2), digestive tract anomalies (n = 3) and hydrops fetalis (n = 2). The average GA of the fetuses was 31 weeks. The antenatal diagnoses were compared with histological data (n = 6) and postnatal work-up (n = 1). Magnetic resonance imaging demonstrated unexpected abnormal fetal liver signal suggestive of iron overload in all cases. The iron overload was confirmed on postnatal biopsy (n = 2) and fetopathology (n = 4). The final diagnosis was hepatic hemosiderosis (haemolytic anaemia (n = 2) and syndromal anomalies (n = 2)) and congenital haemochromatosis (n = 3). In all cases, the liver appeared normal on US. Magnetic resonance is the only imaging technique able to demonstrate liver iron overload in utero. Yet, the study outlines the fundamental role of MR imaging in cases of congenital haemochromatosis. The antenatal diagnosis of such a condition may prompt ante - (in the case of recurrence) or neonatal treatment, which might improve the prognosis. (orig.)

  17. Shift Work, Role Overload, and the Transition to Parenthood

    Science.gov (United States)

    Perry-Jenkins, Maureen; Goldberg, Abbie E.; Pierce, Courtney P.; Sayer, Aline G.

    2007-01-01

    This article examines how the work hours, work schedules, and role overload of working-class couples are related to depressive symptoms and relationship conflict across the transition to parenthood. Data are from 132 dual-earner couples interviewed 5 times across the transition. Multilevel modeling analyses revealed that working evening or night…

  18. A Confirmatory Factor Analysis of Reilly's Role Overload Scale

    Science.gov (United States)

    Thiagarajan, Palaniappan; Chakrabarty, Subhra; Taylor, Ronald D.

    2006-01-01

    In 1982, Reilly developed a 13-item scale to measure role overload. This scale has been widely used, but most studies did not assess the unidimensionality of the scale. Given the significance of unidimensionality in scale development, the current study reports a confirmatory factor analysis of the 13-item scale in two samples. Based on the…

  19. Sport coaching officials and their stressors: Work overload, role ...

    African Journals Online (AJOL)

    Sport officials' concerns over job stressors have become common due to the adverse effect on health. The study sought to examine the associations of work overload, role ambiguity and role conflict, as well as their predictive influence on job satisfaction of sport coaches in Gauteng, South Africa. Data were collected from a ...

  20. Overload prevention in model supports for wind tunnel model testing

    Directory of Open Access Journals (Sweden)

    Anton IVANOVICI

    2015-09-01

    Full Text Available Preventing overloads in wind tunnel model supports is crucial to the integrity of the tested system. Results can only be interpreted as valid if the model support, conventionally called a sting remains sufficiently rigid during testing. Modeling and preliminary calculation can only give an estimate of the sting’s behavior under known forces and moments but sometimes unpredictable, aerodynamically caused model behavior can cause large transient overloads that cannot be taken into account at the sting design phase. To ensure model integrity and data validity an analog fast protection circuit was designed and tested. A post-factum analysis was carried out to optimize the overload detection and a short discussion on aeroelastic phenomena is included to show why such a detector has to be very fast. The last refinement of the concept consists in a fast detector coupled with a slightly slower one to differentiate between transient overloads that decay in time and those that are the result of aeroelastic unwanted phenomena. The decision to stop or continue the test is therefore conservatively taken preserving data and model integrity while allowing normal startup loads and transients to manifest.

  1. Iron overload induces hypogonadism in male mice via extrahypothalamic mechanisms.

    Science.gov (United States)

    Macchi, Chiara; Steffani, Liliana; Oleari, Roberto; Lettieri, Antonella; Valenti, Luca; Dongiovanni, Paola; Romero-Ruiz, Antonio; Tena-Sempere, Manuel; Cariboni, Anna; Magni, Paolo; Ruscica, Massimiliano

    2017-10-15

    Iron overload leads to multiple organ damage including endocrine organ dysfunctions. Hypogonadism is the most common non-diabetic endocrinopathy in primary and secondary iron overload syndromes. To explore the molecular determinants of iron overload-induced hypogonadism with specific focus on hypothalamic derangements. A dysmetabolic male murine model fed iron-enriched diet (IED) and cell-based models of gonadotropin-releasing hormone (GnRH) neurons were used. Mice fed IED showed severe hypogonadism with a significant reduction of serum levels of testosterone (-83%) and of luteinizing hormone (-86%), as well as reduced body weight gain, body fat and plasma leptin. IED mice had a significant increment in iron concentration in testes and in the pituitary. Even if iron challenge of in vitro neuronal models (GN-11 and GT1-7 GnRH cells) resulted in 10- and 5-fold iron content increments, respectively, no iron content changes were found in vivo in hypothalamus of IED mice. Conversely, mice placed on IED showed a significant increment in hypothalamic GnRH gene expression (+34%) and in the intensity of GnRH-neuron innervation of the median eminence (+1.5-fold); similar changes were found in the murine model HFE -/- , resembling human hemochromatosis. IED-fed adult male mice show severe impairment of hypothalamus-pituitary-gonadal axis without a relevant contribution of the hypothalamic compartment, which thus appears sufficiently protected from systemic iron overload. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Stress 2.0: Social Media Overload among Swiss Teenagers

    NARCIS (Netherlands)

    Lutz, Christoph; Ranzini, Giulia; Meckel, Miriam

    2014-01-01

    Technostress and information overload are serious challenges of the information age. An alarming number of people exhibit dangerously intensive media consumption, while Internet and mobile phone addictions are a widespread phenomenon. At the same time, new media overexposure among young people is

  3. 30 CFR 75.518-2 - Incandescent lamps, overload and short circuit protection.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Incandescent lamps, overload and short circuit...-General § 75.518-2 Incandescent lamps, overload and short circuit protection. Incandescent lamps installed... or direct current feeder circuits, need not be provided with separate short circuit or overload...

  4. IMNN: Information Maximizing Neural Networks

    Science.gov (United States)

    Charnock, Tom; Lavaux, Guilhem; Wandelt, Benjamin D.

    2018-04-01

    This software trains artificial neural networks to find non-linear functionals of data that maximize Fisher information: information maximizing neural networks (IMNNs). As compressing large data sets vastly simplifies both frequentist and Bayesian inference, important information may be inadvertently missed. Likelihood-free inference based on automatically derived IMNN summaries produces summaries that are good approximations to sufficient statistics. IMNNs are robustly capable of automatically finding optimal, non-linear summaries of the data even in cases where linear compression fails: inferring the variance of Gaussian signal in the presence of noise, inferring cosmological parameters from mock simulations of the Lyman-α forest in quasar spectra, and inferring frequency-domain parameters from LISA-like detections of gravitational waveforms. In this final case, the IMNN summary outperforms linear data compression by avoiding the introduction of spurious likelihood maxima.

  5. Is the β phase maximal?

    International Nuclear Information System (INIS)

    Ferrandis, Javier

    2005-01-01

    The current experimental determination of the absolute values of the CKM elements indicates that 2 vertical bar V ub /V cb V us vertical bar =(1-z), with z given by z=0.19+/-0.14. This fact implies that irrespective of the form of the quark Yukawa matrices, the measured value of the SM CP phase β is approximately the maximum allowed by the measured absolute values of the CKM elements. This is β=(π/6-z/3) for γ=(π/3+z/3), which implies α=π/2. Alternatively, assuming that β is exactly maximal and using the experimental measurement sin(2β)=0.726+/-0.037, the phase γ is predicted to be γ=(π/2-β)=66.3 o +/-1.7 o . The maximality of β, if confirmed by near-future experiments, may give us some clues as to the origin of CP violation

  6. Strategy to maximize maintenance operation

    OpenAIRE

    Espinoza, Michael

    2005-01-01

    This project presents a strategic analysis to maximize maintenance operations in Alcan Kitimat Works in British Columbia. The project studies the role of maintenance in improving its overall maintenance performance. It provides strategic alternatives and specific recommendations addressing Kitimat Works key strategic issues and problems. A comprehensive industry and competitive analysis identifies the industry structure and its competitive forces. In the mature aluminium industry, the bargain...

  7. Scalable Nonlinear AUC Maximization Methods

    OpenAIRE

    Khalid, Majdi; Ray, Indrakshi; Chitsaz, Hamidreza

    2017-01-01

    The area under the ROC curve (AUC) is a measure of interest in various machine learning and data mining applications. It has been widely used to evaluate classification performance on heavily imbalanced data. The kernelized AUC maximization machines have established a superior generalization ability compared to linear AUC machines because of their capability in modeling the complex nonlinear structure underlying most real world-data. However, the high training complexity renders the kernelize...

  8. FLOUTING MAXIMS IN INDONESIA LAWAK KLUB CONVERSATION

    Directory of Open Access Journals (Sweden)

    Rahmawati Sukmaningrum

    2017-04-01

    Full Text Available This study aims to identify the types of maxims flouted in the conversation in famous comedy show, Indonesia Lawak Club. Likewise, it also tries to reveal the speakers‘ intention of flouting the maxim in the conversation during the show. The writers use descriptive qualitative method in conducting this research. The data is taken from the dialogue of Indonesia Lawak club and then analyzed based on Grice‘s cooperative principles. The researchers read the dialogue‘s transcripts, identify the maxims, and interpret the data to find the speakers‘ intention for flouting the maxims in the communication. The results show that there are four types of maxims flouted in the dialogue. Those are maxim of quality (23%, maxim of quantity (11%, maxim of manner (31%, and maxim of relevance (35. Flouting the maxims in the conversations is intended to make the speakers feel uncomfortable with the conversation, show arrogances, show disagreement or agreement, and ridicule other speakers.

  9. Transplantation in patients with iron overload: is there a place for magnetic resonance imaging? : Transplantation in iron overload.

    Science.gov (United States)

    Mavrogeni, Sophie; Kolovou, Genovefa; Bigalke, Boris; Rigopoulos, Angelos; Noutsias, Michel; Adamopoulos, Stamatis

    2018-03-01

    In iron overload diseases (thalassemia, sickle cell, and myelodysplastic syndrome), iron is deposited in all internal organs, leading to functional abnormalities. Hematopoietic stem cell transplantation (HSCT) is the only treatment offering a potential cure in these diseases. Our aim was to describe the experience in the field and the role of magnetic resonance imaging in the evaluation of iron overload before and after HSCT. Magnetic resonance imaging (MRI), using T2*, is the most commonly used tool to diagnose myocardial-liver iron overload and guide tailored treatment. Currently, HSCT offers complete cure in thalassemia major, after overcoming the immunologic barrier, and should be considered for all patients who have a suitable donor. The overall thalassemia-free survival of low-risk, HLA-matched sibling stem cell transplantation patients is 85-90%, with a 95% overall survival. The problems of rejection and engraftment are improving with the use of adequate immunosuppression. However, a detailed iron assessment of both heart and liver is necessary for pre- and post-transplant evaluation. In iron overload diseases, heart and liver iron evaluation is indispensable not only for the patients' survival, but also for evaluation before and after HSCT.

  10. Effect of overload on the fatigue crack propagation in metastable beta Ti-V alloys

    International Nuclear Information System (INIS)

    Chakrabortty, S.B.; Starke, E.A. Jr.; Lee, E.W.

    1984-01-01

    The effects of overload on the fatigue crack propagation behavior of two Ti-V alloys having different deformation mechanisms were studied. The results are explained in terms of residual stress effects associated with the overload and the removal of these stresses during post-overload cycling. An additional effect occurs during multiple cycle overload when the deformation structure representative of the strain amplitude is believed to form in the overload reverse plastic zone. This structure must be rearranged during cycling at Delta Kb before the baseline FCGR is reached and the process is responsible for part of the delay period. 46 references

  11. Effects of overload on the threshold stress intensity factor for SCC

    International Nuclear Information System (INIS)

    Takahashi, Koji; Ando, Kotoji; Miyazaki, Yuji; Hashikura, Yasuaki

    2009-01-01

    The effects of overload on the threshold stress intensity factor for stress corrosion crack (K ISCC ) of stainless steel were studied. Tensile overload was applied to a wedge opening loaded (WOL) specimen of SUS316. Then, SCC tests were carried out to determine the resultant K ISCC . As a result, the apparent value of K ISCC increases as increasing a stress intensity factor by tensile overload (K OV ). The effects of tensile overload on K ISCC and the threshold stress intensity factor range for fatigue (ΔK th ) were compared. It was found that the effects of tensile overload on K ISCC were larger than that on ΔK th . (author)

  12. Transfusion-associated circulatory overload in adult, medical emergency patients with perspectives on early warning practice

    DEFF Research Database (Denmark)

    Gosmann, Fanny; Nørgaard, Astrid; Rasmussen, Maj-Britt

    2018-01-01

    of transfusion-associated dyspnoea. Vital signs and changes in dyspnoea and blood pressure were registered within the frame of the Early Warning Score, and one case was documented as being transfusion-related in the medical record. No cases were reported to the haemovigilance system. DISCUSSION: The incidence...... to the haemovigilance system. The clinical implications are discussed within the frame of the Early Warning Score. METHODS: We conducted a retrospective audit of electronic hospital medical records of patients receiving blood transfusion in a single medical emergency unit. Patients were admitted during a 6-month period...... and data on symptoms and vital signs were extracted from the records. RESULTS: Of 4,353 consecutively admitted patients, 156 patients were transfused with a total of 411 blood components. The audit identified five cases of transfusion-associated circulatory overload (incidence 3.2%) and four cases...

  13. Salt-water imbalance and fluid overload in hemodialysis patients: a pivotal role of corin.

    Science.gov (United States)

    Ricciardi, Carlo Alberto; Lacquaniti, Antonio; Cernaro, Valeria; Bruzzese, Annamaria; Visconti, Luca; Loddo, Saverio; Santoro, Domenico; Buemi, Michele

    2016-08-01

    Natriuretic peptides (NP) play a key role in regulation of salt and water balance. Corin, a serine protease which activates NP, plays a key role in regulation of blood pressure and cardiac function. The aim of the study was to evaluate the involvement of corin in renal physiopathology, analyze its levels in dialyzed patients and evaluate its relation with fluid overload and comorbidities such as heart failure and blood hypertension. We studied serum corin in uremic patients (n = 20) undergoing hemodialysis therapy (HD) and in healthy subjects (HS). Corin levels in uremic patients were higher than in HS (p role of corin in kidney diseases and to define its diagnostic and prognostic role.

  14. Sex differences in autonomic function following maximal exercise.

    Science.gov (United States)

    Kappus, Rebecca M; Ranadive, Sushant M; Yan, Huimin; Lane-Cordova, Abbi D; Cook, Marc D; Sun, Peng; Harvey, I Shevon; Wilund, Kenneth R; Woods, Jeffrey A; Fernhall, Bo

    2015-01-01

    Heart rate variability (HRV), blood pressure variability, (BPV) and heart rate recovery (HRR) are measures that provide insight regarding autonomic function. Maximal exercise can affect autonomic function, and it is unknown if there are sex differences in autonomic recovery following exercise. Therefore, the purpose of this study was to determine sex differences in several measures of autonomic function and the response following maximal exercise. Seventy-one (31 males and 40 females) healthy, nonsmoking, sedentary normotensive subjects between the ages of 18 and 35 underwent measurements of HRV and BPV at rest and following a maximal exercise bout. HRR was measured at minute one and two following maximal exercise. Males have significantly greater HRR following maximal exercise at both minute one and two; however, the significance between sexes was eliminated when controlling for VO2 peak. Males had significantly higher resting BPV-low-frequency (LF) values compared to females and did not significantly change following exercise, whereas females had significantly increased BPV-LF values following acute maximal exercise. Although males and females exhibited a significant decrease in both HRV-LF and HRV-high frequency (HF) with exercise, females had significantly higher HRV-HF values following exercise. Males had a significantly higher HRV-LF/HF ratio at rest; however, both males and females significantly increased their HRV-LF/HF ratio following exercise. Pre-menopausal females exhibit a cardioprotective autonomic profile compared to age-matched males due to lower resting sympathetic activity and faster vagal reactivation following maximal exercise. Acute maximal exercise is a sufficient autonomic stressor to demonstrate sex differences in the critical post-exercise recovery period.

  15. Maximal Abelian sets of roots

    CERN Document Server

    Lawther, R

    2018-01-01

    In this work the author lets \\Phi be an irreducible root system, with Coxeter group W. He considers subsets of \\Phi which are abelian, meaning that no two roots in the set have sum in \\Phi \\cup \\{ 0 \\}. He classifies all maximal abelian sets (i.e., abelian sets properly contained in no other) up to the action of W: for each W-orbit of maximal abelian sets we provide an explicit representative X, identify the (setwise) stabilizer W_X of X in W, and decompose X into W_X-orbits. Abelian sets of roots are closely related to abelian unipotent subgroups of simple algebraic groups, and thus to abelian p-subgroups of finite groups of Lie type over fields of characteristic p. Parts of the work presented here have been used to confirm the p-rank of E_8(p^n), and (somewhat unexpectedly) to obtain for the first time the 2-ranks of the Monster and Baby Monster sporadic groups, together with the double cover of the latter. Root systems of classical type are dealt with quickly here; the vast majority of the present work con...

  16. Exercise Training Prevents Cardiovascular Derangements Induced by Fructose Overload in Developing Rats.

    Directory of Open Access Journals (Sweden)

    Daniela Farah

    Full Text Available The risks of chronic diseases associated with the increasing consumption of fructose-laden foods are amplified by the lack of regular physical activity and have become a serious public health issue worldwide. Moreover, childhood eating habits are strongly related to metabolic syndrome in adults. Thus, we aimed to investigate the preventive role of exercise training undertaken concurrently with a high fructose diet on cardiac function, hemodynamics, cardiovascular autonomic modulation and oxidative stress in male rats after weaning. Male Wistar rats were divided into 4 groups (n = 8/group: Sedentary control (SC, Trained control (TC, Sedentary Fructose (SF and Trained Fructose (TF. Training was performed on a treadmill (8 weeks, 40-60% of maximum exercise test. Evaluations of cardiac function, hemodynamics, cardiovascular autonomic modulation and oxidative stress in plasma and in left ventricle (LV were performed. Chronic fructose overload induced glucose intolerance and an increase in white adipose tissue (WAT weight, in myocardial performance index (MPI (SF:0.42±0.04 vs. SC:0.24±0.05 and in arterial pressure (SF:122±3 vs. SC:113±1 mmHg associated with increased cardiac and vascular sympathetic modulation. Fructose also induced unfavorable changes in oxidative stress profile (plasmatic protein oxidation- SF:3.30±0.09 vs. SC:1.45±0.08 nmol/mg prot; and LV total antioxidant capacity (TRAP- SF: 2.5±0.5 vs. SC:12.7±1.7 uM trolox. The TF group showed reduced WAT, glucose intolerance, MPI (0.35±0.04, arterial pressure (118±2mmHg, sympathetic modulation, plasmatic protein oxidation and increased TRAP when compared to SF group. Therefore, our findings indicate that cardiometabolic dysfunctions induced by fructose overload early in life may be prevented by moderate aerobic exercise training.

  17. Exercise Training Prevents Cardiovascular Derangements Induced by Fructose Overload in Developing Rats

    Science.gov (United States)

    Farah, Daniela; Nunes, Jonas; Sartori, Michelle; Dias, Danielle da Silva; Sirvente, Raquel; Silva, Maikon B.; Fiorino, Patrícia; Morris, Mariana; Llesuy, Susana; Farah, Vera; Irigoyen, Maria-Cláudia; De Angelis, Kátia

    2016-01-01

    The risks of chronic diseases associated with the increasing consumption of fructose-laden foods are amplified by the lack of regular physical activity and have become a serious public health issue worldwide. Moreover, childhood eating habits are strongly related to metabolic syndrome in adults. Thus, we aimed to investigate the preventive role of exercise training undertaken concurrently with a high fructose diet on cardiac function, hemodynamics, cardiovascular autonomic modulation and oxidative stress in male rats after weaning. Male Wistar rats were divided into 4 groups (n = 8/group): Sedentary control (SC), Trained control (TC), Sedentary Fructose (SF) and Trained Fructose (TF). Training was performed on a treadmill (8 weeks, 40–60% of maximum exercise test). Evaluations of cardiac function, hemodynamics, cardiovascular autonomic modulation and oxidative stress in plasma and in left ventricle (LV) were performed. Chronic fructose overload induced glucose intolerance and an increase in white adipose tissue (WAT) weight, in myocardial performance index (MPI) (SF:0.42±0.04 vs. SC:0.24±0.05) and in arterial pressure (SF:122±3 vs. SC:113±1 mmHg) associated with increased cardiac and vascular sympathetic modulation. Fructose also induced unfavorable changes in oxidative stress profile (plasmatic protein oxidation- SF:3.30±0.09 vs. SC:1.45±0.08 nmol/mg prot; and LV total antioxidant capacity (TRAP)- SF: 2.5±0.5 vs. SC:12.7±1.7 uM trolox). The TF group showed reduced WAT, glucose intolerance, MPI (0.35±0.04), arterial pressure (118±2mmHg), sympathetic modulation, plasmatic protein oxidation and increased TRAP when compared to SF group. Therefore, our findings indicate that cardiometabolic dysfunctions induced by fructose overload early in life may be prevented by moderate aerobic exercise training. PMID:27930685

  18. Performance analysis of SS7 congestion controls under sustained overload

    Science.gov (United States)

    Manfield, David R.; Millsteed, Gregory K.; Zukerman, Moshe

    1994-04-01

    Congestion controls are a key factor in achieving the robust performance required of common channel signaling (CCS) networks in the face of partial network failures and extreme traffic loads, especially as networks become large and carry high traffic volume. The CCITT recommendations define a number of types of congestion control, and the parameters of the controls must be well set in order to ensure their efficacy under transient and sustained signalling network overload. The objective of this paper is to present a modeling approach to the determination of the network parameters that govern the performance of the SS7 congestion controls under sustained overload. Results of the investigation by simulation are presented and discussed.

  19. Culinary plants and their potential impact on metabolic overload.

    Science.gov (United States)

    Kim, Ji Yeon; Kwon, Oran

    2011-07-01

    Contemporary human behavior has led a large proportion of the population to metabolic overload and obesity. Postprandial hyperlipidemia and hyperglycemia evoke redox imbalance in the short term and lead to complex chronic disease in the long term with repeated occurrence. Complex diseases are best prevented with complex components of plants; thus, current nutrition research has begun to focus on the development of plant-based functional foods and dietary supplements for health and well-being. Furthermore, given the wide range of species, parts, and secondary metabolites, culinary plants can contribute significant variety and complexity to the human diet. Although understanding the health benefits of culinary plants has been one of the great challenges in nutritional science due to their inherent complexity, it is an advantageous pursuit. This review will address the challenges and opportunities relating to studies of the health benefits of culinary plants, with an emphasis on obesity attributed to metabolic overload. © 2011 New York Academy of Sciences.

  20. Formal Constraints on Memory Management for Composite Overloaded Operations

    Directory of Open Access Journals (Sweden)

    Damian W.I. Rouson

    2006-01-01

    Full Text Available The memory management rules for abstract data type calculus presented by Rouson, Morris & Xu [15] are recast as formal statements in the Object Constraint Language (OCL and applied to the design of a thermal energy equation solver. One set of constraints eliminates memory leaks observed in composite overloaded expressions with three current Fortran 95/2003 compilers. A second set of constraints ensures economical memory recycling. The constraints are preconditions, postconditions and invariants on overloaded operators and the objects they receive and return. It is demonstrated that systematic run-time assertion checking inspired by the formal constraints facilitated the pinpointing of an exceptionally hard-to-reproduce compiler bug. It is further demonstrated that the interplay between OCL's modeling capabilities and Fortran's programming capabilities led to a conceptual breakthrough that greatly improved the readability of our code by facilitating operator overloading. The advantages and disadvantages of our memory management rules are discussed in light of other published solutions [11,19]. Finally, it is demonstrated that the run-time assertion checking has a negligible impact on performance.

  1. Iron overload in patients with myelodysplastic syndromes: An updated overview.

    Science.gov (United States)

    Moukalled, Nour M; El Rassi, Fuad A; Temraz, Sally N; Taher, Ali T

    2018-06-15

    Myelodysplastic syndromes (MDS) encompass a heterogeneous group of clonal hematopoietic stem cell disorders characterized by a broad clinical spectrum related to ineffective hematopoiesis leading to unilineage or multilineage cytopenias, with a high propensity for transformation to acute myeloid leukemia. Iron overload has been recently identified as one of the important conditions complicating the management of these diverse disorders. The accumulation of iron is mainly related to chronic transfusions; however, evidence suggests a possible role for ineffective erythropoiesis and increased intestinal absorption of iron, related to altered hepcidin and growth differentiation factor-15 levels in the development of hemosiderosis in patients with MDS. In addition to its suggested role in the exacerbation of ineffective erythropoiesis, multiple reports have identified a prognostic implication for the development of iron overload in patients with MDS, with an improvement in overall survival after the initiation of iron chelation therapy. This review includes a detailed discussion of iron overload in patients with MDS whether they are undergoing supportive therapy or curative hematopoietic stem cell transplantation, with a focus on the mechanism, diagnosis, and effect on survival as well as the optimal management of this highly variable complication. Cancer 2018. © 2018 American Cancer Society. © 2018 American Cancer Society.

  2. Cycle length maximization in PWRs using empirical core models

    International Nuclear Information System (INIS)

    Okafor, K.C.; Aldemir, T.

    1987-01-01

    The problem of maximizing cycle length in nuclear reactors through optimal fuel and poison management has been addressed by many investigators. An often-used neutronic modeling technique is to find correlations between the state and control variables to describe the response of the core to changes in the control variables. In this study, a set of linear correlations, generated by two-dimensional diffusion-depletion calculations, is used to find the enrichment distribution that maximizes cycle length for the initial core of a pressurized water reactor (PWR). These correlations (a) incorporate the effect of composition changes in all the control zones on a given fuel assembly and (b) are valid for a given range of control variables. The advantage of using such correlations is that the cycle length maximization problem can be reduced to a linear programming problem

  3. Mild iron overload in patients carrying the HFE S65C gene mutation: a retrospective study in patients with suspected iron overload and healthy controls

    OpenAIRE

    Holmström, P; Marmur, J; Eggertsen, G; Gåfvels, M; Stål, P

    2002-01-01

    Background and aims: The role of the HFE S65C mutation in the development of hepatic iron overload is unknown. The aim of the present study was: (A) to determine the HFE S65C frequency in a Northern European population; and (B) to evaluate whether the presence of the HFE S65C mutation would result in a significant hepatic iron overload.

  4. Maximizing benefits from resource development

    International Nuclear Information System (INIS)

    Skjelbred, B.

    2002-01-01

    The main objectives of Norwegian petroleum policy are to maximize the value creation for the country, develop a national oil and gas industry, and to be at the environmental forefront of long term resource management and coexistence with other industries. The paper presents a graph depicting production and net export of crude oil for countries around the world for 2002. Norway produced 3.41 mill b/d and exported 3.22 mill b/d. Norwegian petroleum policy measures include effective regulation and government ownership, research and technology development, and internationalisation. Research and development has been in five priority areas, including enhanced recovery, environmental protection, deep water recovery, small fields, and the gas value chain. The benefits of internationalisation includes capitalizing on Norwegian competency, exploiting emerging markets and the assurance of long-term value creation and employment. 5 figs

  5. Maximizing synchronizability of duplex networks

    Science.gov (United States)

    Wei, Xiang; Emenheiser, Jeffrey; Wu, Xiaoqun; Lu, Jun-an; D'Souza, Raissa M.

    2018-01-01

    We study the synchronizability of duplex networks formed by two randomly generated network layers with different patterns of interlayer node connections. According to the master stability function, we use the smallest nonzero eigenvalue and the eigenratio between the largest and the second smallest eigenvalues of supra-Laplacian matrices to characterize synchronizability on various duplexes. We find that the interlayer linking weight and linking fraction have a profound impact on synchronizability of duplex networks. The increasingly large inter-layer coupling weight is found to cause either decreasing or constant synchronizability for different classes of network dynamics. In addition, negative node degree correlation across interlayer links outperforms positive degree correlation when most interlayer links are present. The reverse is true when a few interlayer links are present. The numerical results and understanding based on these representative duplex networks are illustrative and instructive for building insights into maximizing synchronizability of more realistic multiplex networks.

  6. Iron overload patients with unknown etiology from national survey in Japan.

    Science.gov (United States)

    Ikuta, Katsuya; Hatayama, Mayumi; Addo, Lynda; Toki, Yasumichi; Sasaki, Katsunori; Tatsumi, Yasuaki; Hattori, Ai; Kato, Ayako; Kato, Koichi; Hayashi, Hisao; Suzuki, Takahiro; Kobune, Masayoshi; Tsutsui, Miyuki; Gotoh, Akihiko; Aota, Yasuo; Matsuura, Motoo; Hamada, Yuzuru; Tokuda, Takahiro; Komatsu, Norio; Kohgo, Yutaka

    2017-03-01

    Transfusion is believed to be the main cause of iron overload in Japan. A nationwide survey on post-transfusional iron overload subsequently led to the establishment of guidelines for iron chelation therapy in this country. To date, however, detailed clinical information on the entire iron overload population in Japan has not been fully investigated. In the present study, we obtained and studied detailed clinical information on the iron overload patient population in Japan. Of 1109 iron overload cases, 93.1% were considered to have occurred post-transfusion. There were, however, 76 cases of iron overload of unknown origin, which suggest that many clinicians in Japan may encounter some difficulty in correctly diagnosing and treating iron overload. Further clinical data were obtained for 32 cases of iron overload of unknown origin; median of serum ferritin was 1860.5 ng/mL. As occurs in post-transfusional iron overload, liver dysfunction was found to be as high as 95.7% when serum ferritin levels exceeded 1000 ng/mL in these patients. Gene mutation analysis of the iron metabolism-related genes in 27 cases of iron overload with unknown etiology revealed mutations in the gene coding hemojuvelin, transferrin receptor 2, and ferroportin; this indicates that although rare, hereditary hemochromatosis does occur in Japan.

  7. VIOLATION OF CONVERSATION MAXIM ON TV ADVERTISEMENTS

    Directory of Open Access Journals (Sweden)

    Desak Putu Eka Pratiwi

    2015-07-01

    Full Text Available Maxim is a principle that must be obeyed by all participants textually and interpersonally in order to have a smooth communication process. Conversation maxim is divided into four namely maxim of quality, maxim of quantity, maxim of relevance, and maxim of manner of speaking. Violation of the maxim may occur in a conversation in which the information the speaker has is not delivered well to his speaking partner. Violation of the maxim in a conversation will result in an awkward impression. The example of violation is the given information that is redundant, untrue, irrelevant, or convoluted. Advertisers often deliberately violate the maxim to create unique and controversial advertisements. This study aims to examine the violation of maxims in conversations of TV ads. The source of data in this research is food advertisements aired on TV media. Documentation and observation methods are applied to obtain qualitative data. The theory used in this study is a maxim theory proposed by Grice (1975. The results of the data analysis are presented with informal method. The results of this study show an interesting fact that the violation of maxim in a conversation found in the advertisement exactly makes the advertisements very attractive and have a high value.

  8. Acute iron overload and oxidative stress in brain

    International Nuclear Information System (INIS)

    Piloni, Natacha E.; Fermandez, Virginia; Videla, Luis A.; Puntarulo, Susana

    2013-01-01

    An in vivo model in rat was developed by intraperitoneally administration of Fe-dextran to study oxidative stress triggered by Fe-overload in rat brain. Total Fe levels, as well as the labile iron pool (LIP) concentration, in brain from rats subjected to Fe-overload were markedly increased over control values, 6 h after Fe administration. In this in vivo Fe overload model, the ascorbyl (A·)/ascorbate (AH − ) ratio, taken as oxidative stress index, was assessed. The A·/AH − ratio in brain was significantly higher in Fe-dextran group, in relation to values in control rats. Brain lipid peroxidation indexes, thiobarbituric acid reactive substances (TBARS) generation rate and lipid radical (LR·) content detected by Electron Paramagnetic Resonance (EPR), in Fe-dextran supplemented rats were similar to control values. However, values of nuclear factor-kappaB deoxyribonucleic acid (NFκB DNA) binding activity were significantly increased (30%) after 8 h of Fe administration, and catalase (CAT) activity was significantly enhanced (62%) 21 h after Fe administration. Significant enhancements in Fe content in cortex (2.4 fold), hippocampus (1.6 fold) and striatum (2.9 fold), were found at 6 h after Fe administration. CAT activity was significantly increased after 8 h of Fe administration in cortex, hippocampus and striatum (1.4 fold, 86, and 47%, respectively). Fe response in the whole brain seems to lead to enhanced NF-κB DNA binding activity, which may contribute to limit oxygen reactive species-dependent damage by effects on the antioxidant enzyme CAT activity. Moreover, data shown here clearly indicate that even though Fe increased in several isolated brain areas, this parameter was more drastically enhanced in striatum than in cortex and hippocampus. However, comparison among the net increase in LR· generation rate, in different brain areas, showed enhancements in cortex lipid peroxidation, without changes in striatum and hippocampus LR· generation rate after 6

  9. Increase in Vascular Injury of Sodium Overloaded Mice May be Related to Vascular Angiotensin Modulation.

    Directory of Open Access Journals (Sweden)

    Cintia Taniguti Lima

    Full Text Available This study aimed to analyzing the effect of chronic sodium overload upon carotid and femoral injury, and its relation to vascular angiotensin modulation. Male C57Bl6 mice were divided in: control (cont, receiving 1% NaCl solution for 2 weeks (salt-2 or 12 weeks (salt-12. Two-weeks before the end of the study, a 2mm catheter was implanted around the left femoral and carotid arteries to induce injury. Blood pressure (BP and heart rate (HR were measured at the end of the study by tail plethysmography. Arteries were collected and prepared for histological analysis to determine arterial thickening and perivascular collagen deposition. Angiotensin II and Ang(1-7 were quantified in fresh arteries using the HPLC method. There were no differences in body weight, BP and HR. Intima/media ratio had a similar increase in both injured arteries of cont and salt-2 mice, but a more pronounced increase was observed in salt-12 mice (31.1±6%. On the other hand, sodium overload modified perivascular collagen deposition, increasing thick fibers (cont: 0.5%; salt-2: 3.4%; salt-12: 0.6% and decreasing thin fibers (cont: 7.4%; salt-2: 0.5%; salt-12: 6.8% in non-injured arteries. Injured arteries presented similar collagen fiber distribution. Angiotensin quantification showed increased Ang(1-7 in salt treated mice (salt-2: +72%; salt-12: +45% with a concomitant decrease in Ang II (salt-2: -54%; salt-12: -60%. Vascular injury increased significantly Ang(1-7 in salt-12 mice (+80%, maintaining Ang II reduction similar to that of a non-injured artery. The lack of changes in BP and HR suggests that the structural changes observed may be due to non-hemodynamic mechanisms such as local renin-angiotensin system. Collagen evaluation suggests that sodium overload induces time-related changes in vascular remodeling. The increase of artery injury with concomitant increase in Ang(1-7 in 12-week treated mice shows a direct association between the duration of salt treatment and the

  10. Working memory overload: fronto-limbic interactions and effects on subsequent working memory function.

    Science.gov (United States)

    Yun, Richard J; Krystal, John H; Mathalon, Daniel H

    2010-03-01

    The human working memory system provides an experimentally useful model for examination of neural overload effects on subsequent functioning of the overloaded system. This study employed functional magnetic resonance imaging in conjunction with a parametric working memory task to characterize the behavioral and neural effects of cognitive overload on subsequent cognitive performance, with particular attention to cognitive-limbic interactions. Overloading the working memory system was associated with varying degrees of subsequent decline in performance accuracy and reduced activation of brain regions central to both task performance and suppression of negative affect. The degree of performance decline was independently predicted by three separate factors operating during the overload condition: the degree of task failure, the degree of amygdala activation, and the degree of inverse coupling between the amygdala and dorsolateral prefrontal cortex. These findings suggest that vulnerability to overload effects in cognitive functioning may be mediated by reduced amygdala suppression and subsequent amygdala-prefrontal interaction.

  11. Maximizing ROI (return on information)

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, B.

    2000-05-01

    The role and importance of managing information are discussed, underscoring the importance by quoting from the report of the International Data Corporation, according to which Fortune 500 companies lost $ 12 billion in 1999 due to inefficiencies resulting from intellectual re-work, substandard performance , and inability to find knowledge resources. The report predicts that this figure will rise to $ 31.5 billion by 2003. Key impediments to implementing knowledge management systems are identified as : the cost and human resources requirement of deployment; inflexibility of historical systems to adapt to change; and the difficulty of achieving corporate acceptance of inflexible software products that require changes in 'normal' ways of doing business. The author recommends the use of model, document and rule-independent systems with a document centered interface (DCI), employing rapid application development (RAD) and object technologies and visual model development, which eliminate these problems, making it possible for companies to maximize their return on information (ROI), and achieve substantial savings in implementation costs.

  12. Maximizing the optical network capacity.

    Science.gov (United States)

    Bayvel, Polina; Maher, Robert; Xu, Tianhua; Liga, Gabriele; Shevchenko, Nikita A; Lavery, Domaniç; Alvarado, Alex; Killey, Robert I

    2016-03-06

    Most of the digital data transmitted are carried by optical fibres, forming the great part of the national and international communication infrastructure. The information-carrying capacity of these networks has increased vastly over the past decades through the introduction of wavelength division multiplexing, advanced modulation formats, digital signal processing and improved optical fibre and amplifier technology. These developments sparked the communication revolution and the growth of the Internet, and have created an illusion of infinite capacity being available. But as the volume of data continues to increase, is there a limit to the capacity of an optical fibre communication channel? The optical fibre channel is nonlinear, and the intensity-dependent Kerr nonlinearity limit has been suggested as a fundamental limit to optical fibre capacity. Current research is focused on whether this is the case, and on linear and nonlinear techniques, both optical and electronic, to understand, unlock and maximize the capacity of optical communications in the nonlinear regime. This paper describes some of them and discusses future prospects for success in the quest for capacity. © 2016 The Authors.

  13. On TCP-based Session Initiation Protocol (SIP) Server Overload Control

    OpenAIRE

    Shen, Charles; Schulzrinne, Henning

    2010-01-01

    The Session Initiation Protocol (SIP) server overload management has attracted interest since SIP is being widely deployed in the Next Generation Networks (NGN) as a core signaling protocol. Yet all existing SIP overload control work is focused on SIP-over-UDP, despite the fact that TCP is increasingly seen as the more viable choice of SIP transport. This paper answers the following questions: is the existing TCP flow control capable of handling the SIP overload problem? If not, why and how c...

  14. Role of work overload toward turnover intention among newly hired public accountants

    OpenAIRE

    Pradana, Andika; Salehudin, Imam

    2013-01-01

    This paper aims to analyze how work overload influences turnover intentions of newly hired public accountants. Job satisfaction, work related stress and work life conflicts are used as mediating variable between work overload and turnover intention. This study employed 141 auditors from several accounting firms operating in the Greater Jakarta region. Six proposed hypotheses was tested using Structural Equation Modeling (SEM). Results showed that work overload has significant effect in increa...

  15. TIMP3 deficiency exacerbates iron overload-mediated cardiomyopathy and liver disease.

    Science.gov (United States)

    Zhabyeyev, Pavel; Das, Subhash K; Basu, Ratnadeep; Shen, Mengcheng; Patel, Vaibhav B; Kassiri, Zamaneh; Oudit, Gavin Y

    2018-05-01

    Chronic iron overload results in heart and liver diseases and is a common cause of morbidity and mortality in patients with genetic hemochromatosis and secondary iron overload. We investigated the role of tissue inhibitor of metalloproteinase 3 (TIMP3) in iron overload-mediated tissue injury by subjecting male mice lacking Timp3 ( Timp3 -/- ) and wild-type (WT) mice to 12 wk of chronic iron overload. Whereas WT mice with iron overload developed diastolic dysfunction, iron-overloaded Timp3 -/- mice showed worsened cardiac dysfunction coupled with systolic dysfunction. In the heart, loss of Timp3 was associated with increased myocardial fibrosis, greater Timp1, matrix metalloproteinase ( Mmp) 2, and Mmp9 expression, increased active MMP-2 levels, and gelatinase activity. Iron overload in Timp3 -/- mice showed twofold higher iron accumulation in the liver compared with WT mice because of constituently lower levels of ferroportin. Loss of Timp3 enhanced the hepatic inflammatory response to iron overload, leading to greater neutrophil and macrophage infiltration and increased hepatic fibrosis. Expression of inflammation-related MMPs (MMP-12 and MMP-13) and inflammatory cytokines (IL-1β and monocyte chemoattractant protein-1) was elevated to a greater extent in iron-overloaded Timp3 -/- livers. Gelatin zymography demonstrated equivalent increases in MMP-2 and MMP-9 levels in WT and Timp3 -/- iron-overloaded livers. Loss of Timp3 enhanced the susceptibility to iron overload-mediated heart and liver injury, suggesting that Timp3 is a key protective molecule against iron-mediated pathology. NEW & NOTEWORTHY In mice, loss of tissue inhibitor of metalloproteinase 3 ( Timp3) was associated with systolic and diastolic dysfunctions, twofold higher hepatic iron accumulation (attributable to constituently lower levels of ferroportin), and increased hepatic inflammation. Loss of Timp3 enhanced the susceptibility to iron overload-mediated injury, suggesting that Timp3 plays a key

  16. Research progress in role of iron overload in non-alcoholic fatty liver disease

    Directory of Open Access Journals (Sweden)

    LI Guangming

    2013-12-01

    Full Text Available Iron overload is an important research focus in non-alcoholic fatty liver disease (NAFLD. The relationship between iron overload and NAFLD is summarized from the assessment method for iron overload, relationship between iron load and hemochromatosis gene mutations, incidence of iron load in NAFLD, and relationship between iron load and progression of NAFLD; the action mechanism of iron overload in the progression of NAFLD is reviewed from the causes of iron overload, relationship between iron overload and lipid metabolism, and relationship between type of iron deposition and liver damage; the significance of iron overload in the diagnosis and treatment of NAFLD is discussed from iron overload as a new marker of risk stratification and potential therapeutic target in NAFLD. It is currently considered that iron overload, whether the cause or result of NAFLD progression, will promote the progression of NAFLD once it occurs; as a new marker of risk stratification and potential therapeutic target in NAFLD, iron load is worthy of further study.

  17. Lactate dehydrogenase regulation in aged skeletal muscle: Regulation by anabolic steroids and functional overload.

    Science.gov (United States)

    Washington, Tyrone A; Healey, Julie M; Thompson, Raymond W; Lowe, Larry L; Carson, James A

    2014-09-01

    Aging alters the skeletal muscle response to overload-induced growth. The onset of functional overload is characterized by increased myoblast proliferation and an altered muscle metabolic profile. The onset of functional overload is associated with increased energy demands that are met through the interconversion of lactate and pyruvate via the activity of lactate dehydrogenase (LDH). Testosterone targets many of the processes activated at the onset of functional overload. However, the effect of aging on this metabolic plasticity at the onset of functional overload and how anabolic steroid administration modulates this response is not well understood. The purpose of this study was to determine if aging would alter overload-induced LDH activity and expression at the onset of functional overload and whether anabolic steroid administration would modulate this response. Five-month and 25-month male Fischer 344xF1 BRN were given nandrolone decanoate (ND) or sham injections for 14days and then the plantaris was functionally overloaded (OV) for 3days by synergist ablation. Aging reduced muscle LDH-A & LDH-B activity 70% (pyoung muscle. Our study provides evidence that aging alters aspects of skeletal muscle metabolic plasticity normally induced by overload and anabolic steroid administration. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. The body of women and the overload of sexuality

    Directory of Open Access Journals (Sweden)

    Rosa Cobo Bedia

    2015-12-01

    Full Text Available This work is approaching to a historically recent social phenomenon: the hipersexualization of women. It looks into its origins and finds that the idea of the sexual freedom that is developed in the 60s, on one side, and the exaltation of the free market, which was developed from the 80s, on the other, come together in the goal of overloading women sexuality. The context in which this process takes place is a free and unlimited market which has understood that women`s bodies are a commodity from which are extracted necessaries appreciations for the social reproduction of contemporary patriarchy and neoliberal capitalism.

  19. Effects of Exogenous Antioxidants on Dietary Iron Overload

    OpenAIRE

    Asare, George A.; Kew, Michael C.; Mossanda, Kensese S.; Paterson, Alan C.; Siziba, Kwanele; Kahler-Venter, Christiana P.

    2008-01-01

    In dietary iron overload, excess hepatic iron promotes liver damage. The aim was to attenuate free radical-induced liver damage using vitamins. Four groups of 60 Wistar rats were studied: group 1 (control) was fed normal diet, group 2 (Fe) 2.5% pentacarbonyl iron (CI) followed by 0.5% Ferrocene, group 3 (Fe + V gp) CI, Ferrocene, plus vitamins A and E (42× and 10× RDA, respectively), group 4 (Fe – V gp) CI, Ferrocene diet, minus vitamins A and E. At 20 months, glutathione peroxidase (GPx), su...

  20. Protection of insulated cables and lines in case of overload

    Energy Technology Data Exchange (ETDEWEB)

    Goltz, M

    1983-01-01

    After DIN 57100 Part 430/VDE 0100 part 430 for the protection of lines and cables was published in June 1981, the discussion flared up again whether this DIN/VDE-regulation is sufficient. Some papers have already been published on the right selection and arrangement of overload protection under normal operational conditions. The aim of this contribution is to explain abnormal operational conditions which are dealt with in DIN 57100 part 430/VDE 0100 part 430 in comments and the annex, and to supply some help for planning and projecting.

  1. Quantification of liver fat in the presence of iron overload.

    Science.gov (United States)

    Horng, Debra E; Hernando, Diego; Reeder, Scott B

    2017-02-01

    To evaluate the accuracy of R2* models (1/T 2 * = R2*) for chemical shift-encoded magnetic resonance imaging (CSE-MRI)-based proton density fat-fraction (PDFF) quantification in patients with fatty liver and iron overload, using MR spectroscopy (MRS) as the reference standard. Two Monte Carlo simulations were implemented to compare the root-mean-squared-error (RMSE) performance of single-R2* and dual-R2* correction in a theoretical liver environment with high iron. Fatty liver was defined as hepatic PDFF >5.6% based on MRS; only subjects with fatty liver were considered for analyses involving fat. From a group of 40 patients with known/suspected iron overload, nine patients were identified at 1.5T, and 13 at 3.0T with fatty liver. MRS linewidth measurements were used to estimate R2* values for water and fat peaks. PDFF was measured from CSE-MRI data using single-R2* and dual-R2* correction with magnitude and complex fitting. Spectroscopy-based R2* analysis demonstrated that the R2* of water and fat remain close in value, both increasing as iron overload increases: linear regression between R2* W and R2* F resulted in slope = 0.95 [0.79-1.12] (95% limits of agreement) at 1.5T and slope = 0.76 [0.49-1.03] at 3.0T. MRI-PDFF using dual-R2* correction had severe artifacts. MRI-PDFF using single-R2* correction had good agreement with MRS-PDFF: Bland-Altman analysis resulted in -0.7% (bias) ± 2.9% (95% limits of agreement) for magnitude-fit and -1.3% ± 4.3% for complex-fit at 1.5T, and -1.5% ± 8.4% for magnitude-fit and -2.2% ± 9.6% for complex-fit at 3.0T. Single-R2* modeling enables accurate PDFF quantification, even in patients with iron overload. 1 J. Magn. Reson. Imaging 2017;45:428-439. © 2016 International Society for Magnetic Resonance in Medicine.

  2. Inherent overload protection for the series resonant converter

    Science.gov (United States)

    King, R. J.; Stuart, T. A.

    1983-01-01

    The overload characteristics of the full bridge series resonant power converter are considered. This includes analyses of the two most common control methods presently in use. The first of these uses a current zero crossing detector to synchronize the control signals and is referred to as the alpha controller. The second is driven by a voltage controlled oscillator and is referred to as the gamma controller. It is shown that the gamma controller has certain reliability advantages in that it can be designed with inherent short circuit protection. Experimental results are included for an 86 kHz converter using power metal-oxide-semiconductor field-effect transistors (MOSFETs).

  3. Does mental exertion alter maximal muscle activation?

    Directory of Open Access Journals (Sweden)

    Vianney eRozand

    2014-09-01

    Full Text Available Mental exertion is known to impair endurance performance, but its effects on neuromuscular function remain unclear. The purpose of this study was to test the hypothesis that mental exertion reduces torque and muscle activation during intermittent maximal voluntary contractions of the knee extensors. Ten subjects performed in a randomized order three separate mental exertion conditions lasting 27 minutes each: i high mental exertion (incongruent Stroop task, ii moderate mental exertion (congruent Stroop task, iii low mental exertion (watching a movie. In each condition, mental exertion was combined with ten intermittent maximal voluntary contractions of the knee extensor muscles (one maximal voluntary contraction every 3 minutes. Neuromuscular function was assessed using electrical nerve stimulation. Maximal voluntary torque, maximal muscle activation and other neuromuscular parameters were similar across mental exertion conditions and did not change over time. These findings suggest that mental exertion does not affect neuromuscular function during intermittent maximal voluntary contractions of the knee extensors.

  4. AUC-Maximizing Ensembles through Metalearning.

    Science.gov (United States)

    LeDell, Erin; van der Laan, Mark J; Petersen, Maya

    2016-05-01

    Area Under the ROC Curve (AUC) is often used to measure the performance of an estimator in binary classification problems. An AUC-maximizing classifier can have significant advantages in cases where ranking correctness is valued or if the outcome is rare. In a Super Learner ensemble, maximization of the AUC can be achieved by the use of an AUC-maximining metalearning algorithm. We discuss an implementation of an AUC-maximization technique that is formulated as a nonlinear optimization problem. We also evaluate the effectiveness of a large number of different nonlinear optimization algorithms to maximize the cross-validated AUC of the ensemble fit. The results provide evidence that AUC-maximizing metalearners can, and often do, out-perform non-AUC-maximizing metalearning methods, with respect to ensemble AUC. The results also demonstrate that as the level of imbalance in the training data increases, the Super Learner ensemble outperforms the top base algorithm by a larger degree.

  5. On maximal massive 3D supergravity

    OpenAIRE

    Bergshoeff , Eric A; Hohm , Olaf; Rosseel , Jan; Townsend , Paul K

    2010-01-01

    ABSTRACT We construct, at the linearized level, the three-dimensional (3D) N = 4 supersymmetric " general massive supergravity " and the maximally supersymmetric N = 8 " new massive supergravity ". We also construct the maximally supersymmetric linearized N = 7 topologically massive supergravity, although we expect N = 6 to be maximal at the non-linear level. (Bergshoeff, Eric A) (Hohm, Olaf) (Rosseel, Jan) P.K.Townsend@da...

  6. Inclusive Fitness Maximization:An Axiomatic Approach

    OpenAIRE

    Okasha, Samir; Weymark, John; Bossert, Walter

    2014-01-01

    Kin selection theorists argue that evolution in social contexts will lead organisms to behave as if maximizing their inclusive, as opposed to personal, fitness. The inclusive fitness concept allows biologists to treat organisms as akin to rational agents seeking to maximize a utility function. Here we develop this idea and place it on a firm footing by employing a standard decision-theoretic methodology. We show how the principle of inclusive fitness maximization and a related principle of qu...

  7. Activity versus outcome maximization in time management.

    Science.gov (United States)

    Malkoc, Selin A; Tonietto, Gabriela N

    2018-04-30

    Feeling time-pressed has become ubiquitous. Time management strategies have emerged to help individuals fit in more of their desired and necessary activities. We provide a review of these strategies. In doing so, we distinguish between two, often competing, motives people have in managing their time: activity maximization and outcome maximization. The emerging literature points to an important dilemma: a given strategy that maximizes the number of activities might be detrimental to outcome maximization. We discuss such factors that might hinder performance in work tasks and enjoyment in leisure tasks. Finally, we provide theoretically grounded recommendations that can help balance these two important goals in time management. Published by Elsevier Ltd.

  8. On the maximal superalgebras of supersymmetric backgrounds

    International Nuclear Information System (INIS)

    Figueroa-O'Farrill, Jose; Hackett-Jones, Emily; Moutsopoulos, George; Simon, Joan

    2009-01-01

    In this paper we give a precise definition of the notion of a maximal superalgebra of certain types of supersymmetric supergravity backgrounds, including the Freund-Rubin backgrounds, and propose a geometric construction extending the well-known construction of its Killing superalgebra. We determine the structure of maximal Lie superalgebras and show that there is a finite number of isomorphism classes, all related via contractions from an orthosymplectic Lie superalgebra. We use the structure theory to show that maximally supersymmetric waves do not possess such a maximal superalgebra, but that the maximally supersymmetric Freund-Rubin backgrounds do. We perform the explicit geometric construction of the maximal superalgebra of AdS 4 X S 7 and find that it is isomorphic to osp(1|32). We propose an algebraic construction of the maximal superalgebra of any background asymptotic to AdS 4 X S 7 and we test this proposal by computing the maximal superalgebra of the M2-brane in its two maximally supersymmetric limits, finding agreement.

  9. Task-oriented maximally entangled states

    International Nuclear Information System (INIS)

    Agrawal, Pankaj; Pradhan, B

    2010-01-01

    We introduce the notion of a task-oriented maximally entangled state (TMES). This notion depends on the task for which a quantum state is used as the resource. TMESs are the states that can be used to carry out the task maximally. This concept may be more useful than that of a general maximally entangled state in the case of a multipartite system. We illustrate this idea by giving an operational definition of maximally entangled states on the basis of communication tasks of teleportation and superdense coding. We also give examples and a procedure to obtain such TMESs for n-qubit systems.

  10. Competing for Attention in Social Media under Information Overload Conditions.

    Science.gov (United States)

    Feng, Ling; Hu, Yanqing; Li, Baowen; Stanley, H Eugene; Havlin, Shlomo; Braunstein, Lidia A

    2015-01-01

    Modern social media are becoming overloaded with information because of the rapidly-expanding number of information feeds. We analyze the user-generated content in Sina Weibo, and find evidence that the spread of popular messages often follow a mechanism that differs from the spread of disease, in contrast to common belief. In this mechanism, an individual with more friends needs more repeated exposures to spread further the information. Moreover, our data suggest that for certain messages the chance of an individual to share the message is proportional to the fraction of its neighbours who shared it with him/her, which is a result of competition for attention. We model this process using a fractional susceptible infected recovered (FSIR) model, where the infection probability of a node is proportional to its fraction of infected neighbors. Our findings have dramatic implications for information contagion. For example, using the FSIR model we find that real-world social networks have a finite epidemic threshold in contrast to the zero threshold in disease epidemic models. This means that when individuals are overloaded with excess information feeds, the information either reaches out the population if it is above the critical epidemic threshold, or it would never be well received.

  11. Competing for Attention in Social Media under Information Overload Conditions.

    Directory of Open Access Journals (Sweden)

    Ling Feng

    Full Text Available Modern social media are becoming overloaded with information because of the rapidly-expanding number of information feeds. We analyze the user-generated content in Sina Weibo, and find evidence that the spread of popular messages often follow a mechanism that differs from the spread of disease, in contrast to common belief. In this mechanism, an individual with more friends needs more repeated exposures to spread further the information. Moreover, our data suggest that for certain messages the chance of an individual to share the message is proportional to the fraction of its neighbours who shared it with him/her, which is a result of competition for attention. We model this process using a fractional susceptible infected recovered (FSIR model, where the infection probability of a node is proportional to its fraction of infected neighbors. Our findings have dramatic implications for information contagion. For example, using the FSIR model we find that real-world social networks have a finite epidemic threshold in contrast to the zero threshold in disease epidemic models. This means that when individuals are overloaded with excess information feeds, the information either reaches out the population if it is above the critical epidemic threshold, or it would never be well received.

  12. Electrochemical sensor for predicting transformer overload by phenol measurement

    Energy Technology Data Exchange (ETDEWEB)

    Bosworth, Timothy; Setford, Steven; Saini, Selwayan [Cranfield Centre for Analytical Science, Cranfield University, Silsoe, Beds MK45 4DT (United Kingdom); Heywood, Richard [National Grid Company Plc, Kelvin Avenue, Leatherhead, Surrey KT22 7ST (United Kingdom)

    2003-03-10

    Transformer overload is a significant problem to the power transmission industry, with severe safety and cost implications. Overload may be predicted by measuring phenol levels in the transformer-insulating oil, arising from the thermolytic degradation of phenol-formaldehyde resins. The development of two polyphenol oxidase (PPO) sensors, based on monitoring the enzymatic consumption of oxygen using an oxygen electrode, or reduction of enzymatically generated o-quinone at a screen-printed electrode (SPE), for the measurement of phenol in transformer oil is reported. Ex-service oils were prepared either by extraction into aqueous electrolyte-buffer, or by direct dilution in propan-2-ol, the latter method being more amenable to simple at-line operation. The oxygen electrode, with a sensitivity of 2.87 nA {mu}g{sup -1} ml{sup -1}, RSD of 7.0-19.9% and accuracy of {+-}8.3% versus the industry standard International Electrotechnical Commission (IEC) method, proved superior to the SPE (sensitivity: 3.02 nA {mu}g{sup -1} ml{sup -1}; RSD: 8.9-18.3%; accuracy: {+-}7.9%) and was considerably more accurate at low phenol concentrations. However, the SPE approach is more amenable to field-based usage for reasons of device simplicity. The method has potential as a rapid and simple screening tool for the at-site monitoring of phenol in transformer oils, thereby reducing incidences of transformer failure.

  13. Chronic Kidney Disease, Fluid Overload and Diuretics: A Complicated Triangle.

    Science.gov (United States)

    Khan, Yusra Habib; Sarriff, Azmi; Adnan, Azreen Syazril; Khan, Amer Hayat; Mallhi, Tauqeer Hussain

    2016-01-01

    Despite promising role of diuretics to manage fluid overload among chronic kidney disease (CKD) patients, their use is associated with adverse renal outcomes. Current study aimed to determine the extent of renal deterioration with diuretic therapy. A total 312 non-dialysis dependent CKD (NDD-CKD) patients were prospectively followed-up for one year. Fluid overload was assessed via bioimpedance spectroscopy. Estimated GFR (eGFR) was calculated from serum creatinine values by using Chronic Kidney Disease- Epidemiology Collaboration (CKD-EPI) equation. Out of 312 patients, 64 (20.5%) were hypovolemic while euvolemia and hypervolemia were observed in 113 (36.1%) and 135 (43.4%) patients. Overall 144 patients were using diuretics among which 98 (72.6%) were hypervolemic, 35 (30.9%) euvolemic and 11 (17.2%) were hypovolemic. The mean decline in estimated GFR of entire cohort was -2.5 ± 1.4 ml/min/1.73m2 at the end of follow up. The use of diuretics was significantly associated with decline in eGFR. A total of 36 (11.5%) patients initiated renal replacement therapy (RRT) and need of RRT was more profound among diuretic users. The use of diuretics was associated with adverse renal outcomes indicated by decline in eGFR and increasing risk of RRT initiation in our cohort of NDD-CKD patients. Therefore, it is cautiously suggested to carefully prescribe diuretics by keeping in view benefit versus harm for each patient.

  14. Designing immersive surgical training against information technology-related overload in the operating room

    NARCIS (Netherlands)

    Pluyter, J.R.

    2012-01-01

    On a theoretical level, this dissertation demonstrates that the “classical” conceptualization of overload in the field of Information Systems being an excessive amount of information is too simplistic. Based on the Emotional-Cognitive Overload Model by Rutkowski and Saunders (2011) this dissertation

  15. Learners' Perceived Information Overload in Online Learning via Computer-Mediated Communication

    Science.gov (United States)

    Chen, Chun-Ying; Pedersen, Susan; Murphy, Karen L.

    2011-01-01

    Many studies report information overload as one of the main problems that students encounter in online learning via computer-mediated communication. This study aimed to explore the sources of online students' information overload and offer suggestions for increasing students' cognitive resources for learning. Participants were 12 graduate students…

  16. Managing Information Overload for Senior Leaders in the 21st Century

    Science.gov (United States)

    Jackson, Jason M.

    2013-01-01

    Information overload is a state where information input exceeds processing capability by an individual, and adverse effects of information overload, such as becoming less productive, making bad decisions, and becoming highly selective, are growing. Guided by Glaser and Strauss' work on grounded theory, this study examined adverse impact of…

  17. Development of an overload control strategy for the Republic of Senegal

    CSIR Research Space (South Africa)

    Nordengen, Paul A

    2006-09-01

    Full Text Available , particularly because there are currently no weighbridges in the country being used for overload control law enforcement. Recognising the need for an effective overload strategy for Senegal, the Ministry of Public Works and Transport decided to initiate a study...

  18. Data Overload Impact on Project Management: How Knowledge Management Systems Can Improve Federal Agencies Effectiveness

    Science.gov (United States)

    Rodriguez, Jacinto

    2013-01-01

    This mixed method exploratory case study was used to explore the effect data overload has on project management, how data overload affects project management effectiveness, how prepared program office staff is to manage multiple projects effectively, and how the program office's organizational structure and data management systems affect project…

  19. Designing a Personalized Guide Recommendation System to Mitigate Information Overload in Museum Learning

    Science.gov (United States)

    Huang, Yong-Ming; Liu, Chien-Hung; Lee, Chun-Yi; Huang, Yueh-Min

    2012-01-01

    Museum learning has received a lot of attention in recent years. Museum learning refers to people's use of museums to acquire knowledge. However, a problem with information overload has caused in engaging in such learning. Information overload signifies that users encounter a mass of information and need to determine whether certain information…

  20. 30 CFR 75.518 - Electric equipment and circuits; overload and short circuit protection.

    Science.gov (United States)

    2010-07-01

    ... short circuit protection. 75.518 Section 75.518 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... Equipment-General § 75.518 Electric equipment and circuits; overload and short circuit protection... installed so as to protect all electric equipment and circuits against short circuit and overloads. Three...

  1. Predicting Role Conflict, Overload and Contagion in Adult Women University Students with Families and Jobs.

    Science.gov (United States)

    Home, Alice M.

    1998-01-01

    Data from 443 women combining work, family, and schooling showed that lower income increased their vulnerability to role conflict. Perceived intensity of student demands was the strongest predictor of role conflict, overload, and contagion (preoccupation with one role while performing another). Conflict and overload were eased somewhat by distance…

  2. Clinical consequences of iron overload in patients with myelodysplastic syndromes: the case for iron chelation therapy.

    Science.gov (United States)

    Shammo, Jamile M; Komrokji, Rami S

    2018-06-14

    Patients with myelodysplastic syndromes (MDS) are at increased risk of iron overload due to ineffective erythropoiesis and chronic transfusion therapy. The clinical consequences of iron overload include cardiac and/or hepatic failure, endocrinopathies, and infection risk. Areas covered: Iron chelation therapy (ICT) can help remove excess iron and ultimately reduce the clinical consequences of iron overload. The authors reviewed recent (last five years) English-language articles from PubMed on the topic of iron overload-related complications and the use of ICT (primarily deferasirox) to improve outcomes in patients with MDS. Expert Commentary: While a benefit of ICT has been more firmly established in other transfusion-dependent conditions such as thalassemia, its role in reducing iron overload in MDS remains controversial due to the lack of prospective controlled data demonstrating a survival benefit. Orally administered chelation agents (e.g., deferasirox), are now available, and observational and/or retrospective data support a survival benefit of using ICT in MDS. The placebo-controlled TELESTO trial (NCT00940602) is currently examining the use of deferasirox in MDS patients with iron overload, and is evaluating specifically whether use of ICT to alleviate iron overload can also reduce iron overload-related complications in MDS and improve survival.

  3. Role overload, pain and physical dysfunction in early rheumatoid or undifferentiated inflammatory arthritis in Canada.

    Science.gov (United States)

    Mustafa, Sally Sabry; Looper, Karl Julian; Zelkowitz, Phyllis; Purden, Margaret; Baron, Murray

    2012-05-03

    Inflammatory arthritis impairs participation in societal roles. Role overload arises when the demands by a given role set exceed the resources; time and energy, to carry out the required tasks. The present study examines the association between role overload and disease outcomes in early inflammatory arthritis (EIA). Patients (n = 104) of 7.61 months mean duration of inflammatory arthritis completed self-report questionnaires on sociodemographics, disease characteristics and role overload. Pain was assessed using the Short Form McGill Pain Questionnaire (MPQ) and physical functioning was measured with the Medical Outcomes Study Short Form 36 (SF-36) physical functioning score. Role overload was measured by the Role Overload Scale. Patients indicated the number of social roles they occupied from a total of the three typical roles; marital, parental and paid work. Participants' mean age was 56 years and 70.2% were female. Role overload was not correlated to the number of social roles, however, it was positively associated with pain (p = 0.004) and negatively associated with physical functioning (p = 0.001). On multivariate analysis, role overload was negatively associated with physical functioning after controlling for the relevant sociodemographic variables. This study identifies a possible reciprocal relationship between role overload and physical functioning in patients with EIA.

  4. "Something's Gotta Give:" Advanced-Degree Seeking Women's Experiences of Sexism, Role Overload, and Psychological Distress

    Science.gov (United States)

    West, Lindsey M.

    2014-01-01

    With the rise in advanced-degree seeking women and the minimal research on the dual impact of sexism and role overload, the current study aims to better understand the impact of sexism and role overload on psychological distress in a particular sample of advanced-degree seeking women. Seventy-six female medical student participants (mean age 24.7)…

  5. The evolution of crack-tip stresses during a fatigue overload event

    International Nuclear Information System (INIS)

    Steuwer, A.; Rahman, M.; Shterenlikht, A.; Fitzpatrick, M.E.; Edwards, L.; Withers, P.J.

    2010-01-01

    The mechanisms responsible for the transient retardation or acceleration of fatigue crack growth subsequent to overloading are a matter of intense debate. Plasticity-induced closure and residual stresses have often been invoked to explain these phenomena, but closure mechanisms are disputed, especially under conditions approximating to generalised plane strain. In this paper we exploit synchrotron radiation to report very high spatial resolution two-dimensional elastic strain and stress maps at maximum and minimum loading measured under plane strain during a normal fatigue cycle, as well as during and after a 100% overload event, in ultra-fine grained AA5091 aluminium alloy. These observations provide direct evidence of the material stress state in the vicinity of the crack-tip in thick samples. Significant compressive residual stresses were found both in front of and behind the crack-tip immediately following the overload event. The effective stress intensity at the crack-tip was determined directly from the local stress field measured deep within the bulk (plane strain) by comparison with linear elastic fracture mechanical theory. This agrees well with that nominally applied at maximum load and 100% overload. After overload, however, the stress fields were not well described by classical K fields due to closure-related residual stresses. Little evidence of overload closure was observed sometime after the overload event, in our case possibly because the overload plastic zone was very small.

  6. Melatonin protects bone marrow mesenchymal stem cells against iron overload-induced aberrant differentiation and senescence.

    Science.gov (United States)

    Yang, Fan; Yang, Lei; Li, Yuan; Yan, Gege; Feng, Chao; Liu, Tianyi; Gong, Rui; Yuan, Ye; Wang, Ning; Idiiatullina, Elina; Bikkuzin, Timur; Pavlov, Valentin; Li, Yang; Dong, Chaorun; Wang, Dawei; Cao, Yang; Han, Zhenbo; Zhang, Lai; Huang, Qi; Ding, Fengzhi; Bi, Zhengang; Cai, Benzhi

    2017-10-01

    Bone marrow mesenchymal stem cells (BMSCs) are an expandable population of stem cells which can differentiate into osteoblasts, chondrocytes and adipocytes. Dysfunction of BMSCs in response to pathological stimuli contributes to bone diseases. Melatonin, a hormone secreted from pineal gland, has been proved to be an important mediator in bone formation and mineralization. The aim of this study was to investigate whether melatonin protected against iron overload-induced dysfunction of BMSCs and its underlying mechanisms. Here, we found that iron overload induced by ferric ammonium citrate (FAC) caused irregularly morphological changes and markedly reduced the viability in BMSCs. Consistently, osteogenic differentiation of BMSCs was significantly inhibited by iron overload, but melatonin treatment rescued osteogenic differentiation of BMSCs. Furthermore, exposure to FAC led to the senescence in BMSCs, which was attenuated by melatonin as well. Meanwhile, melatonin was able to counter the reduction in cell proliferation by iron overload in BMSCs. In addition, protective effects of melatonin on iron overload-induced dysfunction of BMSCs were abolished by its inhibitor luzindole. Also, melatonin protected BMSCs against iron overload-induced ROS accumulation and membrane potential depolarization. Further study uncovered that melatonin inhibited the upregulation of p53, ERK and p38 protein expressions in BMSCs with iron overload. Collectively, melatonin plays a protective role in iron overload-induced osteogenic differentiation dysfunction and senescence through blocking ROS accumulation and p53/ERK/p38 activation. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Why cross-national differences in role overload? Don't overlook ambient temperature!

    NARCIS (Netherlands)

    Van de Vliert, E.; Van Yperen, N.W.

    The finding that, across nations, power distance (expected and accepted unequal interpersonal influence) Is positively related to role overload (Peterson et al., 1995) might he an artifact of the relation between role overload and ambient temperature or other third factors. We related data on power

  8. Role Overload, Job Satisfaction, Leisure Satisfaction, and Psychological Health among Employed Women

    Science.gov (United States)

    Pearson, Quinn M.

    2008-01-01

    Role overload, job satisfaction, leisure satisfaction, and psychological health were measured for 155 women who were employed full time. Role overload was negatively correlated with psychological health, job satisfaction, and leisure satisfaction. Job satisfaction and leisure satisfaction were positively correlated with psychological health.…

  9. Overload training inhibits phagocytosis and ROS generation of peritoneal macrophages: role of IGF-1 and MGF.

    Science.gov (United States)

    Xiao, Weihua; Chen, Peijie; Wang, Ru; Dong, Jingmei

    2013-01-01

    We tested the hypothesis that overload training inhibits the phagocytosis and the reactive oxygen species (ROS) generation of peritoneal macrophages (Mϕs), and that insulin-like growth factor-1(IGF-1) and mechano-growth factor (MGF) produced by macrophages may contribute to this process. Rats were randomized to two groups, sedentary control group (n = 10) and overload training group (n = 10). The rats of overload training group were subjected to 11 weeks of experimental training protocol. Blood sample was used to determine the content of hemoglobin, testosterone, and corticosterone. The phagocytosis and the ROS generation of Mϕs were measured by the uptake of neutral red and the flow cytometry, respectively. IGF-1 and MGF mRNA levels in Mϕs were determined by real-time PCR. In addition, we evaluated the effects of IGF-1 and MGF peptide on phagocytosis and ROS generation of Mϕs in vitro. The data showed that overload training significantly decreased the body weight (19.3 %, P overload training significantly decreased the phagocytosis (27 %, P overload training group increased significantly compared with the control group (21-fold and 92-fold, respectively; P overload training inhibits the phagocytosis and the ROS generation of peritoneal macrophages, and that MGF produced by macrophages may play a key role in this process. This may represent a novel mechanism of immune suppression induced by overload training.

  10. Information Overload in the New World of Work: Qualitative Study into the Reasons and Countermeasures

    NARCIS (Netherlands)

    ter Heerdt, Jeroen; Bondarouk, Tatiana; Ruel, Hubertus Johannes Maria; Guiderdoni-Jourdain, Karine; Oiry, Ewan

    2009-01-01

    In this chapter the authors present a revision of the information overload concept elaborated by Eppler and Mengis (2004). The main elements of our approach are literature synopsis and analysis, qualitative semi-structured interviews, and discussion. Their review of the information overload concept

  11. Coping with Overload and Stress: Men and Women in Dual-Earner Families

    Science.gov (United States)

    Higgins, Chris A.; Duxbury, Linda E.; Lyons, Sean T.

    2010-01-01

    This study tested gender differences in a model positing relationships between work and family demands, overload, 4 coping mechanisms, and stress. The coping mechanisms were hypothesized to moderate the relationship between overload and stress. The sample consisted of 1,404 men and 1,623 women in dual-earner families. Respondents relied on 2…

  12. Reliability Analysis and Overload Capability Assessment of Oil-Immersed Power Transformers

    Directory of Open Access Journals (Sweden)

    Chen Wang

    2016-01-01

    Full Text Available Smart grids have been constructed so as to guarantee the security and stability of the power grid in recent years. Power transformers are a most vital component in the complicated smart grid network. Any transformer failure can cause damage of the whole power system, within which the failures caused by overloading cannot be ignored. This research gives a new insight into overload capability assessment of transformers. The hot-spot temperature of the winding is the most critical factor in measuring the overload capacity of power transformers. Thus, the hot-spot temperature is calculated to obtain the duration running time of the power transformers under overloading conditions. Then the overloading probability is fitted with the mature and widely accepted Weibull probability density function. To guarantee the accuracy of this fitting, a new objective function is proposed to obtain the desired parameters in the Weibull distributions. In addition, ten different mutation scenarios are adopted in the differential evolutionary algorithm to optimize the parameter in the Weibull distribution. The final comprehensive overload capability of the power transformer is assessed by the duration running time as well as the overloading probability. Compared with the previous studies that take no account of the overloading probability, the assessment results obtained in this research are much more reliable.

  13. Maximally Entangled Multipartite States: A Brief Survey

    International Nuclear Information System (INIS)

    Enríquez, M; Wintrowicz, I; Życzkowski, K

    2016-01-01

    The problem of identifying maximally entangled quantum states of a composite quantum systems is analyzed. We review some states of multipartite systems distinguished with respect to certain measures of quantum entanglement. Numerical results obtained for 4-qubit pure states illustrate the fact that the notion of maximally entangled state depends on the measure used. (paper)

  14. Utility maximization and mode of payment

    NARCIS (Netherlands)

    Koning, R.H.; Ridder, G.; Heijmans, R.D.H.; Pollock, D.S.G.; Satorra, A.

    2000-01-01

    The implications of stochastic utility maximization in a model of choice of payment are examined. Three types of compatibility with utility maximization are distinguished: global compatibility, local compatibility on an interval, and local compatibility on a finite set of points. Keywords:

  15. Corporate Social Responsibility and Profit Maximizing Behaviour

    OpenAIRE

    Becchetti, Leonardo; Giallonardo, Luisa; Tessitore, Maria Elisabetta

    2005-01-01

    We examine the behavior of a profit maximizing monopolist in a horizontal differentiation model in which consumers differ in their degree of social responsibility (SR) and consumers SR is dynamically influenced by habit persistence. The model outlines parametric conditions under which (consumer driven) corporate social responsibility is an optimal choice compatible with profit maximizing behavior.

  16. Fatigue crack growth behaviour of carbon steel piping material subjected to single overload/under-load

    International Nuclear Information System (INIS)

    Arora, Punit; Tripathi, R.; Singh, P.K.; Bhasin, V.; Vijayan, P.K.

    2016-01-01

    The objective of the present study is to understand the Fatigue Crack Growth Rate (FCGR) behaviour after single over-load/ under-load event on carbon steel piping material. The tests have been carried out on standard Compact Tension (CT) specimens. The effect of different crack length to width ratio (a/W) of specimen and overload/under-load ratios on FCGR have been studied. The studies have shown significant reduction in FCG rate after overload event. The strain field has been measured using Digital Image Correlation (DIC) technique ahead of the crack tip to quantify the plastic zone size due to overload and constant amplitude load. In addition, plastic zone calculations have also been carried out using 3D finite element analyses for the prediction of post overload FCGR/ life. The predicted FCGR are in agreement with experimentally determined FCGR. (author)

  17. Inclusive fitness maximization: An axiomatic approach.

    Science.gov (United States)

    Okasha, Samir; Weymark, John A; Bossert, Walter

    2014-06-07

    Kin selection theorists argue that evolution in social contexts will lead organisms to behave as if maximizing their inclusive, as opposed to personal, fitness. The inclusive fitness concept allows biologists to treat organisms as akin to rational agents seeking to maximize a utility function. Here we develop this idea and place it on a firm footing by employing a standard decision-theoretic methodology. We show how the principle of inclusive fitness maximization and a related principle of quasi-inclusive fitness maximization can be derived from axioms on an individual׳s 'as if preferences' (binary choices) for the case in which phenotypic effects are additive. Our results help integrate evolutionary theory and rational choice theory, help draw out the behavioural implications of inclusive fitness maximization, and point to a possible way in which evolution could lead organisms to implement it. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Maximal Entanglement in High Energy Physics

    Directory of Open Access Journals (Sweden)

    Alba Cervera-Lierta, José I. Latorre, Juan Rojo, Luca Rottoli

    2017-11-01

    Full Text Available We analyze how maximal entanglement is generated at the fundamental level in QED by studying correlations between helicity states in tree-level scattering processes at high energy. We demonstrate that two mechanisms for the generation of maximal entanglement are at work: i $s$-channel processes where the virtual photon carries equal overlaps of the helicities of the final state particles, and ii the indistinguishable superposition between $t$- and $u$-channels. We then study whether requiring maximal entanglement constrains the coupling structure of QED and the weak interactions. In the case of photon-electron interactions unconstrained by gauge symmetry, we show how this requirement allows reproducing QED. For $Z$-mediated weak scattering, the maximal entanglement principle leads to non-trivial predictions for the value of the weak mixing angle $\\theta_W$. Our results are a first step towards understanding the connections between maximal entanglement and the fundamental symmetries of high-energy physics.

  19. Changes in bacteria composition and efficiency of constructed wetlands under sustained overloads: A modeling experiment.

    Science.gov (United States)

    Boano, F; Rizzo, A; Samsó, R; García, J; Revelli, R; Ridolfi, L

    2018-01-15

    The average organic and hydraulic loads that Constructed Wetlands (CWs) receive are key parameters for their adequate long-term functioning. However, over their lifespan they will inevitably be subject to either episodic or sustained overloadings. Despite that the consequences of sustained overloading are well known (e.g., clogging), the threshold of overloads that these systems can tolerate is difficult to determine. Moreover, the mechanisms that might sustain the buffering capacity (i.e., the reduction of peaks in nutrient load) during overloads are not well understood. The aim of this work is to evaluate the effect of sudden but sustained organic and hydraulic overloads on the general functioning of CWs. To that end, the mathematical model BIO_PORE was used to simulate five different scenarios, based on the features and operation conditions of a pilot CW system: a control simulation representing the average loads; 2 simulations representing +10% and +30% sustained organic overloads; one simulation representing a sustained +30% hydraulic overload; and one simulation with sustained organic and hydraulic overloads of +15% each. Different model outputs (e.g., total bacterial biomass and its spatial distribution, effluent concentrations) were compared among different simulations to evaluate the effects of such operation changes. Results reveal that overloads determine a temporary decrease in removal efficiency before microbial biomass adapts to the new conditions and COD removal efficiency is recovered. Increasing organic overloads cause stronger temporary decreases in COD removal efficiency compared to increasing hydraulic loads. The pace at which clogging develops increases by 10% for each 10% increase on the organic load. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Enzymatically modified isoquercitrin supplementation intensifies plantaris muscle fiber hypertrophy in functionally overloaded mice.

    Science.gov (United States)

    Kohara, Akiko; Machida, Masanao; Setoguchi, Yuko; Ito, Ryouichi; Sugitani, Masanori; Maruki-Uchida, Hiroko; Inagaki, Hiroyuki; Ito, Tatsuhiko; Omi, Naomi; Takemasa, Tohru

    2017-01-01

    Enzymatically modified isoquercitrin (EMIQ) is produced from rutin using enzymatic hydrolysis followed by treatment with glycosyltransferase in the presence of dextrin to add glucose residues. EMIQ is absorbed in the same way as quercetin, a powerful antioxidant reported to prevent disused muscle atrophy by targeting mitochondria and to have ergogenic effects. The present study investigated the effect of EMIQ on skeletal muscle hypertrophy induced by functional overload. In Study 1, 6-week-old ICR male mice were divided into 4 groups: sham-operated control, sham-operated EMIQ, overload-operated control, and overload-operated EMIQ groups. In Study 2, mice were divided into 3 groups: overload-operated whey control, overload-operated whey/EMIQ (low dose), and overload-operated whey/EMIQ (high dose) groups. The functional overload of the plantaris muscle was induced by ablation of the synergist (gastrocnemius and soleus) muscles. EMIQ and whey protein were administered with food. Three weeks after the operation, the cross-sectional area and minimal fiber diameter of the plantaris muscle fibers were measured. In Study 1, functional overload increased the cross-sectional area and minimal fiber diameter of the plantaris muscle. EMIQ supplementation significantly increased the cross-sectional area and minimal fiber diameter of the plantaris muscle in both the sham-operated and overload-operated groups. In Study 2, EMIQ supplementation combined with whey protein administration significantly increased the cross-sectional area and minimal fiber diameter of the plantaris muscle. EMIQ, even when administered as an addition to whey protein supplementation, significantly intensified the fiber hypertrophy of the plantaris muscle in functionally overloaded mice. EMIQ supplementation also induced fiber hypertrophy of the plantaris in sham-operated mice.

  1. Functional overload attenuates plantaris atrophy in tumor-bearing rats

    International Nuclear Information System (INIS)

    Otis, Jeffrey S; Lees, Simon J; Williams, Jay H

    2007-01-01

    Late stage cancer malignancies may result in severe skeletal muscle wasting, fatigue and reduced quality of life. Resistance training may attenuate these derangements in cancer patients, but how this hypertrophic response relates to normal muscle adaptations in healthy subjects is unknown. Here, we determined the effect of resistance training on muscle mass and myosin heavy chain (MHC) isoform composition in plantaris muscles from tumor-bearing (TB) rats. Age- and gender-matched Buffalo rats were used for all studies (n = 6/group). Suspensions of Morris Hepatoma MH7777 cells or normal saline were injected subcutaneously into the dorsum. Six weeks after cell implantation, muscles from TB rats were harvested, weighed and processed for ATP-independent proteasome activity assays. Once tumor-induced atrophy had been established, subgroups of TB rats underwent unilateral, functional overload (FO). Healthy, sham-operated rats served as controls. After six weeks, the extent of plantaris hypertrophy was calculated and MHC isoform compositions were determined by gel electrophoresis. Six weeks of tumor growth reduced body mass and the relative masses of gastrocnemius, plantaris, tibialis anterior, extensor digitorum longus, and diaphragm muscles (p ≤ 0.05). Percent reductions in body mass had a strong, negative correlation to final tumor size (r = -0.78). ATP-independent proteasome activity was increased in plantaris muscles from TB rats (p ≤ 0.05). In healthy rats, functional overload (FO) increased plantaris mass ~44% compared to the contralateral control muscle, and increased the relative percentage of MHC type I and decreased the relative percentage of MHC type IIb compared to the sham-operated controls (p ≤ 0.05). Importantly, plantaris mass was increased ~24% in TB-FO rats and adaptations to MHC isoform composition were consistent with normal, resistance-trained muscles. Despite significant skeletal muscle derangements due to cancer, muscle retains the capacity to

  2. Exploration of overloaded cation exchange chromatography for monoclonal antibody purification.

    Science.gov (United States)

    Liu, Hui F; McCooey, Beth; Duarte, Tiago; Myers, Deanna E; Hudson, Terry; Amanullah, Ashraf; van Reis, Robert; Kelley, Brian D

    2011-09-28

    Cation exchange chromatography using conventional resins, having either diffusive or perfusive flow paths, operated in bind-elute mode has been commonly employed in monoclonal antibody (MAb) purification processes. In this study, the performance of diffusive and perfusive cation exchange resins (SP-Sepharose FF (SPSFF) and Poros 50HS) and a convective cation exchange membrane (Mustang S) and monolith (SO(3) Monolith) were compared. All matrices were utilized in an isocratic state under typical binding conditions with an antibody load of up to 1000 g/L of chromatographic matrix. The dynamic binding capacity of the cation exchange resins is typically below 100 g/L resin, so they were loaded beyond the point of anticipated MAb break through. All of the matrices performed similarly in that they effectively retained host cell protein and DNA during the loading and wash steps, while antibody flowed through each matrix after its dynamic binding capacity was reached. The matrices differed, though, in that conventional diffusive and perfusive chromatographic resins (SPSFF and Poros 50HS) demonstrated a higher binding capacity for high molecular weight species (HMW) than convective flow matrices (membrane and monolith); Poros 50HS displayed the highest HMW binding capacity. Further exploration of the conventional chromatographic resins in an isocratic overloaded mode demonstrated that the impurity binding capacity was well maintained on Poros 50HS, but not on SPSFF, when the operating flow rate was as high as 36 column volumes per hour. Host cell protein and HMW removal by Poros 50HS was affected by altering the loading conductivity. A higher percentage of host cell protein removal was achieved at a low conductivity of 3 mS/cm. HMW binding capacity was optimized at 5 mS/cm. Our data from runs on Poros 50HS resin also showed that leached protein A and cell culture additive such as gentamicin were able to be removed under the isocratic overloaded condition. Lastly, a MAb

  3. Liver iron overloading in captive muriquis (Brachyteles spp.).

    Science.gov (United States)

    Santos, Stéfanie V; Strefezzi, Ricardo De F; Pissinatti, Alcides; Catão-Dias, José L

    2011-04-01

    Iron accumulation was investigated qualitatively and quantitatively in the liver of 15 captive Brachyteles spp. Hepatic hemosiderosis index (HHI) was determined as the area percentage of the liver parenchyma occupied by hemosiderin and ferritin deposits, through computerized histomorphometric analysis of Prussian blue-stained histologic sections. All studied animals presented liver hemosiderosis, and HHI ranged from 0.2% to 41.7%. There were no significant differences in HHI between muriqui species or genders, and no correlations were detected among HHI and age, time in captivity or body mass. Iron deposits were accompanied by other hepatic disorders. This is the first study addressing the occurrence and consequences of iron overloading in the liver of muriquis. We propose that hemosiderosis may act as a contribute factor for the development of hepatic injuries. Further studies are advised to clarify the role of diet in the pathogenesis of hemosiderosis in these atelids. © 2010 John Wiley & Sons A/S.

  4. Iron overload in the liver diagnostic and quantification

    International Nuclear Information System (INIS)

    Alustiza, Jose M.; Castiella, Agustin; Juan, Maria D. de; Emparanza, Jose I.; Artetxe, Jose; Uranga, Maite

    2007-01-01

    Hereditary Hemochromatosis is the most frequent modality of iron overload. Since 1996 genetic tests have facilitated significantly the non-invasive diagnosis of the disease. There are however many cases of negative genetic tests that require confirmation by hepatic iron quantification which is traditionally performed by hepatic biopsy. There are many studies that have demonstrated the possibility of performing hepatic iron quantification with Magnetic Resonance. However, a consensus has not been reached yet regarding the technique or the possibility to reproduce the same method of calculus in different machines. This article reviews the state of the art of the question and delineates possible future lines to standardise this non-invasive method of hepatic iron quantification

  5. Iron overload in the liver diagnostic and quantification

    Energy Technology Data Exchange (ETDEWEB)

    Alustiza, Jose M. [Osatek SA, P Dr. Beguiristain 109, 20014, San Sebastian, Guipuzcoa (Spain)]. E-mail: jmalustiza@osatek.es; Castiella, Agustin [Osatek SA, P Dr. Beguiristain 109, 20014, San Sebastian, Guipuzcoa (Spain); Juan, Maria D. de [Osatek SA, P Dr. Beguiristain 109, 20014, San Sebastian, Guipuzcoa (Spain); Emparanza, Jose I. [Osatek SA, P Dr. Beguiristain 109, 20014, San Sebastian, Guipuzcoa (Spain); Artetxe, Jose [Osatek SA, P Dr. Beguiristain 109, 20014, San Sebastian, Guipuzcoa (Spain); Uranga, Maite [Osatek SA, P Dr. Beguiristain 109, 20014, San Sebastian, Guipuzcoa (Spain)

    2007-03-15

    Hereditary Hemochromatosis is the most frequent modality of iron overload. Since 1996 genetic tests have facilitated significantly the non-invasive diagnosis of the disease. There are however many cases of negative genetic tests that require confirmation by hepatic iron quantification which is traditionally performed by hepatic biopsy. There are many studies that have demonstrated the possibility of performing hepatic iron quantification with Magnetic Resonance. However, a consensus has not been reached yet regarding the technique or the possibility to reproduce the same method of calculus in different machines. This article reviews the state of the art of the question and delineates possible future lines to standardise this non-invasive method of hepatic iron quantification.

  6. Operator overloading as an enabling technology for automatic differentiation

    International Nuclear Information System (INIS)

    Corliss, G.F.; Griewank, A.

    1993-01-01

    We present an example of the science that is enabled by object-oriented programming techniques. Scientific computation often needs derivatives for solving nonlinear systems such as those arising in many PDE algorithms, optimization, parameter identification, stiff ordinary differential equations, or sensitivity analysis. Automatic differentiation computes derivatives accurately and efficiently by applying the chain rule to each arithmetic operation or elementary function. Operator overloading enables the techniques of either the forward or the reverse mode of automatic differentiation to be applied to real-world scientific problems. We illustrate automatic differentiation with an example drawn from a model of unsaturated flow in a porous medium. The problem arises from planning for the long-term storage of radioactive waste

  7. Coping with an exogenous glucose overload: glucose kinetics of rainbow trout during graded swimming.

    Science.gov (United States)

    Choi, Kevin; Weber, Jean-Michel

    2016-03-15

    This study examines how chronically hyperglycemic rainbow trout modulate glucose kinetics in response to graded exercise up to critical swimming speed (Ucrit), with or without exogenous glucose supply. Our goals were 1) to quantify the rates of hepatic glucose production (Ra glucose) and disposal (Rd glucose) during graded swimming, 2) to determine how exogenous glucose affects the changes in glucose fluxes caused by exercise, and 3) to establish whether exogenous glucose modifies Ucrit or the cost of transport. Results show that graded swimming causes no change in Ra and Rd glucose at speeds below 2.5 body lengths per second (BL/s), but that glucose fluxes may be stimulated at the highest speeds. Excellent glucoregulation is also achieved at all exercise intensities. When exogenous glucose is supplied during exercise, trout suppress hepatic production from 16.4 ± 1.6 to 4.1 ± 1.7 μmol·kg(-1)·min(-1) and boost glucose disposal to 40.1 ± 13 μmol·kg(-1)·min(-1). These responses limit the effects of exogenous glucose to a 2.5-fold increase in glycemia, whereas fish showing no modulation of fluxes would reach dangerous levels of 114 mM of blood glucose. Exogenous glucose reduces metabolic rate by 16% and, therefore, causes total cost of transport to decrease accordingly. High glucose availability does not improve Ucrit because the fish are unable to take advantage of this extra fuel during maximal exercise and rely on tissue glycogen instead. In conclusion, trout have a remarkable ability to adjust glucose fluxes that allows them to cope with the cumulative stresses of a glucose overload and graded exercise. Copyright © 2016 the American Physiological Society.

  8. Effect of Progressive Volume-Based Overload During Plyometric Training on Explosive and Endurance Performance in Young Soccer Players.

    Science.gov (United States)

    Ramírez-Campillo, Rodrigo; Henríquez-Olguín, Carlos; Burgos, Carlos; Andrade, David C; Zapata, Daniel; Martínez, Cristian; Álvarez, Cristian; Baez, Eduardo I; Castro-Sepúlveda, Mauricio; Peñailillo, Luis; Izquierdo, Mikel

    2015-07-01

    The purpose of the study was to compare the effects of progressive volume-based overload with constant volume-based overload on muscle explosive and endurance performance adaptations during a biweekly short-term (i.e., 6 weeks) plyometric training intervention in young soccer players. Three groups of young soccer players (age 13.0 ± 2.3 years) were divided into: control (CG; n = 8) and plyometric training with (PPT; n = 8) and without (NPPT; n = 8) a progressive increase in volume (i.e., 16 jumps per leg per week, with an initial volume of 80 jumps per leg each session). Bilateral and unilateral horizontal and vertical countermovement jump with arms (CMJA), 20-cm drop jump reactive strength index (RSI20), maximal kicking velocity (MKV), 10-m sprint, change of direction speed (CODS), and Yo-Yo intermittent recovery level 1 test (Yo-Yo IR1) were measured. Although both experimental groups significantly increased CMJA, RSI20, CODS, and endurance performance, only PPT showed a significant improvement in MKV and 10-m sprint time. In addition, only PPT showed a significantly higher performance improvement in jumping, MKV, and Yo-Yo IR1 compared with CG. Also, PPT showed higher meaningful improvement compared with NPPT in all (except 1) jump performance measures. Furthermore, although PPT involved a higher total volume compared with NPPT, training efficiency (i.e., percentage change in performance/total jump volume) was similar between groups. Our results show that PPT and NPPT ensured significant improvement in muscle explosive and endurance performance measures. However, a progressive increase in plyometric training volume seems more advantageous to induce soccer-specific performance improvements.

  9. Predischarge maximal exercise test identifies risk for cardiac death in patients with acute myocardial infarction

    DEFF Research Database (Denmark)

    Nielsen, J R; Mickley, H; Damsgaard, E M

    1990-01-01

    A maximal exercise test was performed in 54 patients with acute myocardial infarction (AMI) before discharge and in 49 age-matched control subjects. The long-term prognosis was assessed after an average follow-up of 7.6 years in AMI patients and 5.8 years in control subjects. The maximal work...... capacity and systolic blood pressure increase in AMI patients was 59% that of control subjects (p less than 0.001). Seventeen AMI patients had significant ST-segment shifts, 13 with ST depression and 4 with ST elevation. In AMI patients experiencing a cardiac death during follow-up the maximal work...... were of no significant value. In this study maximal work capacity turned out to be the best single exercise variable for identifying groups of AMI patients with very low and relative high risk of cardiac death. When all 3 exercise variables were combined, the predischarge maximal exercise test...

  10. Study of overload effects in bainitic steel by synchrotron X-ray diffraction

    Directory of Open Access Journals (Sweden)

    P. Lopez-Crespo

    2013-07-01

    Full Text Available This work presents an in-situ characterisation of crack-tip strain fields following an overload by means of synchrotron X-ray diffraction. The study is made on very fine grained bainitic steel, thus allowing a very high resolution so that small changes occurring around the crack-tip were captured along the crack plane at the mid-thickness of the specimen. We have followed the crack as it grew through the overload location. Once the crack-tip has progressed past the overload event there is strong evidence that the crack faces contact in the region of the overload event (though not in the immediate vicinity of the current locations of the crack tip at Kmin even when the crack has travelled 1mm beyond the overload location. It was also found that at Kmax the peak tensile strain ahead of the crack-tip decreases soon after the overload is applied and then gradually recovers as the crack grows past the compressive region created by the overload.

  11. Changes in cardiac output and incidence of volume overload in cirrhotics receiving 20% albumin infusion.

    Science.gov (United States)

    Shasthry, Saggere M; Kumar, Manoj; Khumuckham, Jelen S; Sarin, Shiv Kumar

    2017-08-01

    Patients with cirrhosis are prone to develop volume over load, have increased capillary permeability and latent or overt cardiomyopathy. Whether albumin infusion causes volume overload in cirrhotics has not been adequately studied. Ninety nine consecutive cirrhotic patients receiving 1gm per kg albumin infusion were evaluated for development of volume overload. Clinical, echocardiographic and haemodynamic changes were closely monitored during and after albumin infusion. Thirty (30.30%) patients developed volume overload. Patients with higher BMI (P=.003), lower CTP (P=.01) and MELD (P=.034) were more often associated with the development of volume overload. Though baseline diastolic dysfunction was present in 82.8% of the patients, it did not influence the development of volume overload or changes in the cardiac output. The cardiac output increased significantly after albumin infusion (4.9±1.554 L/min to 5.86±1.85 L/min, Palbumin infusion develop volume overload, specially, those with higher BMI and lower severity of liver disease. Cardiac output increases after albumin infusion, and, baseline diastolic dysfunction has little effect on the development of volume overload or changes in cardiac output. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Bipartite Bell Inequality and Maximal Violation

    International Nuclear Information System (INIS)

    Li Ming; Fei Shaoming; Li-Jost Xian-Qing

    2011-01-01

    We present new bell inequalities for arbitrary dimensional bipartite quantum systems. The maximal violation of the inequalities is computed. The Bell inequality is capable of detecting quantum entanglement of both pure and mixed quantum states more effectively. (general)

  13. HEALTH INSURANCE: CONTRIBUTIONS AND REIMBURSEMENT MAXIMAL

    CERN Document Server

    HR Division

    2000-01-01

    Affected by both the salary adjustment index on 1.1.2000 and the evolution of the staff members and fellows population, the average reference salary, which is used as an index for fixed contributions and reimbursement maximal, has changed significantly. An adjustment of the amounts of the reimbursement maximal and the fixed contributions is therefore necessary, as from 1 January 2000.Reimbursement maximalThe revised reimbursement maximal will appear on the leaflet summarising the benefits for the year 2000, which will soon be available from the divisional secretariats and from the AUSTRIA office at CERN.Fixed contributionsThe fixed contributions, applicable to some categories of voluntarily insured persons, are set as follows (amounts in CHF for monthly contributions):voluntarily insured member of the personnel, with complete coverage:815,- (was 803,- in 1999)voluntarily insured member of the personnel, with reduced coverage:407,- (was 402,- in 1999)voluntarily insured no longer dependent child:326,- (was 321...

  14. Maximal Inequalities for Dependent Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jorgensen, Jorgen

    2016-01-01

    Maximal inequalities play a crucial role in many probabilistic limit theorem; for instance, the law of large numbers, the law of the iterated logarithm, the martingale limit theorem and the central limit theorem. Let X-1, X-2,... be random variables with partial sums S-k = X-1 + ... + X-k. Then a......Maximal inequalities play a crucial role in many probabilistic limit theorem; for instance, the law of large numbers, the law of the iterated logarithm, the martingale limit theorem and the central limit theorem. Let X-1, X-2,... be random variables with partial sums S-k = X-1 + ... + X......-k. Then a maximal inequality gives conditions ensuring that the maximal partial sum M-n = max(1) (...

  15. Maximizing Function through Intelligent Robot Actuator Control

    Data.gov (United States)

    National Aeronautics and Space Administration — Maximizing Function through Intelligent Robot Actuator Control Successful missions to Mars and beyond will only be possible with the support of high-performance...

  16. An ethical justification of profit maximization

    DEFF Research Database (Denmark)

    Koch, Carsten Allan

    2010-01-01

    In much of the literature on business ethics and corporate social responsibility, it is more or less taken for granted that attempts to maximize profits are inherently unethical. The purpose of this paper is to investigate whether an ethical argument can be given in support of profit maximizing...... behaviour. It is argued that some form of consequential ethics must be applied, and that both profit seeking and profit maximization can be defended from a rule-consequential point of view. It is noted, however, that the result does not apply unconditionally, but requires that certain form of profit (and...... utility) maximizing actions are ruled out, e.g., by behavioural norms or formal institutions....

  17. A definition of maximal CP-violation

    International Nuclear Information System (INIS)

    Roos, M.

    1985-01-01

    The unitary matrix of quark flavour mixing is parametrized in a general way, permitting a mathematically natural definition of maximal CP violation. Present data turn out to violate this definition by 2-3 standard deviations. (orig.)

  18. A cosmological problem for maximally symmetric supergravity

    International Nuclear Information System (INIS)

    German, G.; Ross, G.G.

    1986-01-01

    Under very general considerations it is shown that inflationary models of the universe based on maximally symmetric supergravity with flat potentials are unable to resolve the cosmological energy density (Polonyi) problem. (orig.)

  19. Insulin resistance and maximal oxygen uptake

    DEFF Research Database (Denmark)

    Seibaek, Marie; Vestergaard, Henrik; Burchardt, Hans

    2003-01-01

    BACKGROUND: Type 2 diabetes, coronary atherosclerosis, and physical fitness all correlate with insulin resistance, but the relative importance of each component is unknown. HYPOTHESIS: This study was undertaken to determine the relationship between insulin resistance, maximal oxygen uptake......, and the presence of either diabetes or ischemic heart disease. METHODS: The study population comprised 33 patients with and without diabetes and ischemic heart disease. Insulin resistance was measured by a hyperinsulinemic euglycemic clamp; maximal oxygen uptake was measured during a bicycle exercise test. RESULTS......: There was a strong correlation between maximal oxygen uptake and insulin-stimulated glucose uptake (r = 0.7, p = 0.001), and maximal oxygen uptake was the only factor of importance for determining insulin sensitivity in a model, which also included the presence of diabetes and ischemic heart disease. CONCLUSION...

  20. Maximal supergravities and the E10 model

    International Nuclear Information System (INIS)

    Kleinschmidt, Axel; Nicolai, Hermann

    2006-01-01

    The maximal rank hyperbolic Kac-Moody algebra e 10 has been conjectured to play a prominent role in the unification of duality symmetries in string and M theory. We review some recent developments supporting this conjecture

  1. Influence of different propellant systems on ablation of EPDM insulators in overload state

    Science.gov (United States)

    Guan, Yiwen; Li, Jiang; Liu, Yang; Xu, Tuanwei

    2018-04-01

    This study examines the propellants used in full-scale solid rocket motors (SRM) and investigates how insulator ablation is affected by two propellant formulations (A and B) during flight overload conditions. An experimental study, theoretical analysis, and numerical simulations were performed to discover the intrinsic causes of insulator ablation rates from the perspective of lab-scaled ground-firing tests, the decoupling of thermochemical ablation, and particle erosion. In addition, the difference in propellant composition, and the insulator charring layer microstructure were analyzed. Results reveal that the degree of insulator ablation is positively correlated with the propellant burn rate, particle velocity, and aggregate concentrations during the condensed phase. A lower ratio of energetic additive material in the AP oxidizer of the propellant is promising for the reduction in particle size and increase in the burn rate and pressure index. However, the overall higher velocity of a two-phase flow causes severe erosion of the insulation material. While the higher ratio of energetic additive to the AP oxidizer imparts a smaller ablation rate to the insulator (under lab-scale test conditions), the slag deposition problem in the combustion chamber may cause catastrophic consequences for future large full-scale SRM flight experiments.

  2. Gaussian maximally multipartite-entangled states

    Science.gov (United States)

    Facchi, Paolo; Florio, Giuseppe; Lupo, Cosmo; Mancini, Stefano; Pascazio, Saverio

    2009-12-01

    We study maximally multipartite-entangled states in the context of Gaussian continuous variable quantum systems. By considering multimode Gaussian states with constrained energy, we show that perfect maximally multipartite-entangled states, which exhibit the maximum amount of bipartite entanglement for all bipartitions, only exist for systems containing n=2 or 3 modes. We further numerically investigate the structure of these states and their frustration for n≤7 .

  3. Gaussian maximally multipartite-entangled states

    International Nuclear Information System (INIS)

    Facchi, Paolo; Florio, Giuseppe; Pascazio, Saverio; Lupo, Cosmo; Mancini, Stefano

    2009-01-01

    We study maximally multipartite-entangled states in the context of Gaussian continuous variable quantum systems. By considering multimode Gaussian states with constrained energy, we show that perfect maximally multipartite-entangled states, which exhibit the maximum amount of bipartite entanglement for all bipartitions, only exist for systems containing n=2 or 3 modes. We further numerically investigate the structure of these states and their frustration for n≤7.

  4. Neutrino mass textures with maximal CP violation

    International Nuclear Information System (INIS)

    Aizawa, Ichiro; Kitabayashi, Teruyuki; Yasue, Masaki

    2005-01-01

    We show three types of neutrino mass textures, which give maximal CP violation as well as maximal atmospheric neutrino mixing. These textures are described by six real mass parameters: one specified by two complex flavor neutrino masses and two constrained ones and the others specified by three complex flavor neutrino masses. In each texture, we calculate mixing angles and masses, which are consistent with observed data, as well as Majorana CP phases

  5. Why firms should not always maximize profits

    OpenAIRE

    Kolstad, Ivar

    2006-01-01

    Though corporate social responsibility (CSR) is on the agenda of most major corporations, corporate executives still largely support the view that corporations should maximize the returns to their owners. There are two lines of defence for this position. One is the Friedmanian view that maximizing owner returns is the corporate social responsibility of corporations. The other is a position voiced by many executives, that CSR and profits go together. This paper argues that the first position i...

  6. Maximally Informative Observables and Categorical Perception

    OpenAIRE

    Tsiang, Elaine

    2012-01-01

    We formulate the problem of perception in the framework of information theory, and prove that categorical perception is equivalent to the existence of an observable that has the maximum possible information on the target of perception. We call such an observable maximally informative. Regardless whether categorical perception is real, maximally informative observables can form the basis of a theory of perception. We conclude with the implications of such a theory for the problem of speech per...

  7. PENGARUH WORK OVERLOAD DAN WORK FAMILY CONFLICT TERHADAP TURNOVER INTENTION YANG DIMEDIASI OLEH WORK EXHAUSTION

    Directory of Open Access Journals (Sweden)

    Nurul Hidayatin Nisa

    2016-01-01

    Full Text Available The purpose of this research was to examine factors that determine turnover intention in medical representative at PT. APL. To be known before that medical representatives have high percentage in turnover. The research using work exhaustion as mediation to determine the relationship between works overload and work family conflict of turnover intention. Research method is quantitative approach in causal research. The analysis tools are AMOS and T-Sobel. Findings of this research are both work overload and work family conflict berpengaruh with work exhaustion and turnover intention, work exhaustion mediated work overload and work family conflict over turnover intention.

  8. Information overload an international challenge to professional engineers and technical communicators

    CERN Document Server

    Ulijn, J M; Fazal, Zohra

    2012-01-01

    "This book covers the ever-increasing problem of information overload from both the professional and academic perspectives. Focusing on the needs of practicing engineers and professional communicators, it addresses the causes and costs of information overload, along with strategies and techniques for reducing and minimizing its negative effects. The theoretical framework of information overload and ideas for future research are also presented. The book brings together an international group of authors, providing a truly global point of view on this important, rarely covered topic"--

  9. Trust in management as a buffer of the relationships between overload and strain.

    Science.gov (United States)

    Harvey, Steve; Kelloway, E Kevin; Duncan-Leiper, Leslie

    2003-10-01

    This study examined the role of trust in management as a moderating factor in work overload's impact on personal strain (i.e., burnout, psychological strain, and work's interference with family). Participants were 94 employees of an accounting firm responding to a survey. The results were supportive of all study propositions. Both work overload and trust in management had the expected negative and positive main effects on the outcomes variables, respectively. The impact of work overload on the outcome variables was moderated by employees' trust in management. The significance of these results and areas of future research are discussed. 2003 APA

  10. Effect of overload on SCC growth in stainless steels in high temperature water

    International Nuclear Information System (INIS)

    Xue, He; Peng, Qunjia; Shoji, Tetsuo

    2009-01-01

    By incorporating the film slip-dissolution/oxidation model and the elastic-plastic finite element method (EPFEM), the effect of the overload on stress corrosion cracking (SCC) growth rate of stainless steel in high temperature water is discussed in this paper. Results show that SCC growth rate of a 20% cold worked 316L stainless steel in high temperature water decrease in the overload affected zone ahead of the growing crack tip. Therefore, a reasonable overload could availably reduce the SCC growth rate during a certain in-service period. (author)

  11. Fluid overload correction and cardiac history influence brain natriuretic peptide evolution in incident haemodialysis patients.

    Science.gov (United States)

    Chazot, Charles; Vo-Van, Cyril; Zaoui, Eric; Vanel, Thierry; Hurot, Jean Marc; Lorriaux, Christie; Mayor, Brice; Deleaval, Patrick; Jean, Guillaume

    2011-08-01

    Brain natriuretic peptide (BNP) is a cardiac peptide secreted by ventricle myocardial cells under stretch constraint. Increased BNP has been shown associated with increased mortality in end-stage renal disease patients. In patients starting haemodialysis (HD), both fluid overload and cardiac history are frequently present and may be responsible for a high BNP plasma level. We report in this study the evolution of BNP levels in incident HD patients, its relationship with fluid removal and cardiac history as well as its prognostic value. Forty-six patients (female/male: 21/25; 68.6 ± 14.5 years old) surviving at least 6 months after HD treatment onset were retrospectively analysed. Plasma BNP (Chemoluminescent Microparticule ImmunoAssay on i8200 Architect Abbott, Paris, France; normal value < 100 pg/mL) was assessed at HD start and during the second quarter of HD treatment (Q2). At dialysis start, the plasma BNP level was 1041 ± 1178 pg/mL (range: 14-4181 pg/mL). It was correlated with age (P = 0.0017) and was significantly higher in males (P = 0.0017) and in patients with cardiac disease history (P = 0.001). The plasma BNP level at baseline was not related to the mortality risk. At Q2, predialysis systolic blood pressure (BP) decreased from 140.5 ± 24.5 to 129.4 ± 20.6 mmHg (P = 0.0001) and the postdialysis body weight by 7.6 ± 8.4% (P < 0.0001). The BNP level decreased to 631 ± 707 pg/mL (P = 0.01) at Q2. Its variation was significantly correlated with systolic BP decrease (P = 0.006). A high BNP level was found associated with an increased risk of mortality. Hence, plasma BNP levels decreased during the first months of HD treatment during the dry weight quest. Whereas initial BNP values were not associated with increased mortality risk, the BNP level at Q2 was independently predictive of mortality. Hence, BNP is a useful tool to follow patient dehydration after dialysis start. Initial fluid overload may act as a confounding factor for its value as a

  12. Effects of chronic fructose overload on renal dopaminergic system: alteration of urinary L-dopa/dopamine index correlates to hypertension and precedes kidney structural damage.

    Science.gov (United States)

    Rukavina Mikusic, Natalia L; Kouyoumdzian, Nicolás M; Del Mauro, Julieta S; Cao, Gabriel; Trida, Verónica; Gironacci, Mariela M; Puyó, Ana M; Toblli, Jorge E; Fernández, Belisario E; Choi, Marcelo R

    2018-01-01

    Insulin resistance induced by a high-fructose diet has been associated to hypertension and renal damage. The aim of this work was to assess alterations in the urinary L-dopa/dopamine ratio over three time periods in rats with insulin resistance induced by fructose overload and its correlation with blood pressure levels and the presence of microalbuminuria and reduced nephrin expression as markers of renal structural damage. Male Sprague-Dawley rats were randomly divided into six groups: control (C) (C4, C8 and C12) with tap water to drink and fructose-overloaded (FO) rats (FO4, FO8 and FO12) with a fructose solution (10% w/v) to drink for 4, 8 and 12 weeks. A significant increase of the urinary L-dopa/dopamine ratio was found in FO rats since week 4, which positively correlated to the development of hypertension and preceded in time the onset of microalbuminuria and reduced nephrin expression observed on week 12 of treatment. The alteration of this ratio was associated to an impairment of the renal dopaminergic system, evidenced by a reduction in renal dopamine transporters and dopamine D1 receptor expression, leading to an overexpression and overactivation of the enzyme Na + , K + -ATPase with sodium retention. In conclusion, urinary L-dopa/dopamine ratio alteration in rats with fructose overload positively correlated to the development of hypertension and preceded in time the onset of renal structural damage. This is the first study to propose the use of the urinary L-dopa/dopamine index as marker of renal dysfunction that temporarily precedes kidney structural damage induced by fructose overload. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Effect of sonic driving on maximal aerobic performance.

    Science.gov (United States)

    Brilla, L.R.; Hatcher, Stefanie

    2000-07-01

    The study purpose was to evaluate antecedent binaural stimulation (ABS) on maximal aerobic physical performance. Twenty-two healthy, physically active subjects, 21-34 years, randomly received one of two preparations for each session: 15 min of quiet (BLANK) or percussive sonic driving at 200+ beats per minute (bpm) using a recorded compact disc (FSS, Mill Valley, CA) with headphones (ABS). Baseline HR, blood pressure (BP), and breathing frequency (f(br)) were obtained. During each condition, HR and f(br) were recorded at 3-min intervals. The graded maximal treadmill testing was administered immediately postpreparation session on separate days, with at least 48 h rest between sessions. There were significant differences in the antecedent period means between the two conditions, ABS (HR: 70.2 +/- 10.7 bpm; f(br): 18.5 +/- 3.3 br min(-1); BP: 134.5/87.9 +/- 13.6/9.2 mm Hg) and BLANK (HR: 64.6 +/- 7.9; f(br): 14.3 +/- 2.9; BP: 126.7/80.3 +/- 12.1/8.6). Differences were noted for each 3-min interval and pre- postantecedent period. The maximal graded exercise test (GXT) results showed that there was a small but significant (P 0.05). There may be a latency to ABS related to entrainment or imagery-enhanced warm-up. Am. J. Hum. Biol. 12:558-565, 2000. Copyright 2000 Wiley-Liss, Inc.

  14. Shareholder, stakeholder-owner or broad stakeholder maximization

    OpenAIRE

    Mygind, Niels

    2004-01-01

    With reference to the discussion about shareholder versus stakeholder maximization it is argued that the normal type of maximization is in fact stakeholder-owner maxi-mization. This means maximization of the sum of the value of the shares and stake-holder benefits belonging to the dominating stakeholder-owner. Maximization of shareholder value is a special case of owner-maximization, and only under quite re-strictive assumptions shareholder maximization is larger or equal to stakeholder-owner...

  15. Modification of a Volume-Overload Heart Failure Model to Track Myocardial Remodeling and Device-Related Reverse Remodeling

    Science.gov (United States)

    Tuzun, Egemen; Bick, Roger; Kadipasaoglu, Cihan; Conger, Jeffrey L.; Poindexter, Brian J.; Gregoric, Igor D.; Frazier, O. H.; Towbin, Jeffrey A.; Radovancevic, Branislav

    2011-01-01

    Purpose. To provide an ovine model of ventricular remodeling and reverse remodeling by creating congestive heart failure (CHF) and then treating it by implanting a left ventricular assist device (LVAD). Methods. We induced volume-overload heart failure in 2 sheep; 20 weeks later, we implanted an LVAD and assessed recovery 11 weeks thereafter. We examined changes in histologic and hemodynamic data and levels of cellular markers of CHF. Results. After CHF induction, we found increases in LV end-diastolic pressure, LV systolic and diastolic dimensions, wall thickness, left atrial diameter, and atrial natriuretic protein (ANP) and endothelin-1 (ET-1) levels; β-adrenergic receptor (BAR) and dystrophin expression decreased markedly. Biopsies confirmed LV remodeling. After LVAD support, LV systolic and diastolic dimensions, wall thickness, and mass, and ANP and ET-1 levels decreased. Histopathologic and hemodynamic markers improved, and BAR and dystrophin expression normalized. Conclusions. We describe a successful sheep model for ventricular and reverse remodeling. PMID:22347659

  16. Attenuated hypertrophic response to pressure overload in a lamin A/C haploinsufficiency mouse

    OpenAIRE

    Cupesi, Mihaela; Yoshioka, Jun; Gannon, Joseph; Kudinova, Anastacia; Stewart, Colin L.; Lammerding, Jan

    2009-01-01

    Inherited mutations cause approximately 30% of all dilated cardiomyopathy cases, with autosomal dominant mutations in the LMNA gene accounting for more than one third of these. The LMNA gene encodes the nuclear envelope proteins lamins A and C, which provide structural support to the nucleus and also play critical roles in transcriptional regulation. Functional deletion of a single allele is sufficient to trigger dilated cardiomyopathy in humans and mice. However, whereas Lmna−/− mice develop...

  17. Cardiac myocyte follistatin-like 1 functions to attenuate hypertrophy following pressure overload

    NARCIS (Netherlands)

    Shimano, Masayuki; Ouchi, Noriyuki; Nakamura, Kazuto; van Wijk, Bram; Ohashi, Koji; Asaumi, Yasuhide; Higuchi, Akiko; Pimentel, David R.; Sam, Flora; Murohara, Toyoaki; van den Hoff, Maurice J. B.; Walsh, Kenneth

    2011-01-01

    Factors secreted by the heart, referred to as "cardiokines," have diverse actions in the maintenance of cardiac homeostasis and remodeling. Follistatin-like 1 (Fstl1) is a secreted glycoprotein expressed in the adult heart and is induced in response to injurious conditions that promote myocardial

  18. Structural alterations in heart valves during left ventricular pressure overload in the rat

    NARCIS (Netherlands)

    Willems, I. E.; Havenith, M. G.; Smits, J. F.; Daemen, M. J.

    1994-01-01

    Heart valves are an important denominator of the function of the heart but detailed studies of structural alterations of heart valves after hemodynamic changes are lacking. Structural alterations of heart valves, including DNA synthesis, collagen mRNA, and protein concentration were measured in

  19. Synthesis of total protein (TP) and myosin heavy chain (HC) isozymes in pressure overloaded rabbit hearts

    International Nuclear Information System (INIS)

    Nagai, R.; Martin, B.J.; Pritzl, N.; Zak, R.; Low, R.B.; Stirewalt, W.S.; Alpert, N.R.; Litten, R.Z.

    1986-01-01

    Pulmonary artery banding (PO) leads to a rapid increase in right ventricular (RV) weight as well as a shift toward β myosin isozyme. They determined: (1) the contributions of changes in the capacity (RNA content) and efficiency of total protein synthesis to the increase in RV weight; and (2) the relative contributions of translational and pretranslational mechanisms to the shift in myosin HC isotypes. The rates of synthesis in vivo of TP, α- and β-HC were measured by a constant infusion technique using 3 H-leucine. TP synthesis was 7 +/- 2(SD) mg/day in control (RV:367 +/- 70 mg) and was increased by 2.6 fold at day 2 and 2.9 fold at day 4 following PO (p < 0.01). RV RNA content was increased by 83% at day 2 and 103% at day 4 PO (p < 0.05). The efficiency of synthesis (rate/RNA) was also significantly higher at these time points (1.4- and 1.3-fold). β-HC synthesis was 0.6 +/- 0.2 mg/day in control and increased by 2.6 fold at day 2 and 3.5 fold at day 4 following PO. In contrast, the rate of synthesis of α-HC was unchanged. The relative rates of β-HC to total HC synthesis was correlated linearly with the relative levels of β-myosin mRNA as measured by S1 nuclease mapping. They conclude that increases in the proportion of β-HC myosin following PO is due to increases in the relative amount of β-myosin mRNA and therefore involves modulation of a pretranslational mechanism

  20. Iron overload in a teenager with xerocytosis: the importance of nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    Assis, Reijâne Alves de; Kassab, Carolina; Seguro, Fernanda Salles; Costa, Fernando Ferreira; Silveira, Paulo Augusto Achucarro; Wood, John; Hamerschlak, Nelson

    2013-01-01

    To report a case of iron overload secondary to xerocytosis, a rare disease in a teenager, diagnosed, by T2* magnetic resonance imaging. We report the case of a symptomatic patient with xerocytosis, a ferritin level of 350ng/mL and a significant cardiac iron overload. She was diagnosed by T2* magnetic resonance imaging and received chelation therapy Ektacytometric analysis confirmed the diagnosis of hereditary xerocytosis. Subsequent T2* magnetic resonance imaging demonstrated complete resolution of the iron overload in various organs, as a new echocardiography revealed a complete resolution of previous cardiac alterations. The patient remains in chelation therapy. Xerocytosis is a rare autosomal dominant genetic disorder characterized by dehydrated stomatocytosis. The patient may present with intense fatigue and iron overload. We suggest the regular use of T2* magnetic resonance imaging for the diagnosis and control of the response to iron chelation in xerocytosis, and we believe it can be used also in other hemolytic anemia requiring transfusions

  1. Crack growth retardation due to micro-roughness: a mechanism for overload effects in fatigue

    International Nuclear Information System (INIS)

    Suresh, S.

    1982-01-01

    A new mechanism for fatigue crack growth retardation following an overload is presented in this paper, based on a micro-roughness model. It is reasoned, with the aid of extensive experimental evidence available in the literature, that retardation following an overload is governed by the micromechanisms of near-threshold crack growth. This model is found to rationalize a number of hitherto unexplained experimental observations. Moreover, the present arguments, which suggest that plasticity-induced crack closure is not likely to be the primary mechanism for retardation following single overloads, do not exclude the role of residual stresses or blunting, but provide further mechanistic basis to account for the inconsistencies in the previous models. Additional sources of prolonged retardation, in terms of crack closure due to corrosion debris formed in moist environments, are suggested. It is pointed out that such environmental effects could play an important role in post-overload crack growth in certain alloy systems

  2. Work Overload and Turnover Intention of Junior Auditors in Greater Jakarta, Indonesia

    Directory of Open Access Journals (Sweden)

    Andika Pradana

    2015-11-01

    Full Text Available This paper aims to analyze how work overload influences turnover intentions of newly hired junior auditors in public accounting offices. Job satisfaction, work related stress and work life conflicts are used as mediating variables between work overload and turnover intention. This study employed 141 auditors from several accounting firms operating in the Greater Jakarta region. The sample was selected using purposive sampling. Three mediation hypotheses were tested using Structural Equation Modeling (SEM. The results show that work overload has a significant effect on increasing turnover intention through both job satisfaction and work related stress. In comparison, work overload does not influence turnover intention through work life balance. This may be due to the nature of the respondents, in which a majority of the newly hired accountants employed in this study are unmarried.

  3. WORK OVERLOAD AND TURNOVER INTENTION OF JUNIOR AUDITORS IN GREATER JAKARTA, INDONESIA

    Directory of Open Access Journals (Sweden)

    Andika Pradana

    2015-11-01

    Full Text Available This paper aims to analyze how work overload influences turnover intentions of newly hired junior auditors in public accounting offices. Job satisfaction, work related stress and work life conflicts are used as mediating variables between work overload and turnover intention. This study employed 141 auditors from several accounting firms operating in the Greater Jakarta region. The sample was selected using purposive sampling. Three mediation hypotheses were tested using Structural Equation Modeling (SEM. The results show that work overload has a significant effect on increas- ing turnover intention through both job satisfaction and work related stress. In comparison, work overload does not influence turnover intention through work life balance. This may be due to the nature of the respondents, in which a majority of the newly hired accountants employed in this study are unmarried.

  4. Iron overload in a teenager with xerocytosis: the importance of nuclear magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Assis, Reijâne Alves de; Kassab, Carolina; Seguro, Fernanda Salles [Hospital Israelita Albert Einstein, São Paulo, SP (Brazil); Costa, Fernando Ferreira [Universidade Estadual de Campinas, Campinas, SP (Brazil); Silveira, Paulo Augusto Achucarro [Hospital Israelita Albert Einstein, São Paulo, SP (Brazil); Wood, John [University of Southern California, California (United States); Hamerschlak, Nelson [Hospital Israelita Albert Einstein, São Paulo, SP (Brazil)

    2013-07-01

    To report a case of iron overload secondary to xerocytosis, a rare disease in a teenager, diagnosed, by T2* magnetic resonance imaging. We report the case of a symptomatic patient with xerocytosis, a ferritin level of 350ng/mL and a significant cardiac iron overload. She was diagnosed by T2* magnetic resonance imaging and received chelation therapy Ektacytometric analysis confirmed the diagnosis of hereditary xerocytosis. Subsequent T2* magnetic resonance imaging demonstrated complete resolution of the iron overload in various organs, as a new echocardiography revealed a complete resolution of previous cardiac alterations. The patient remains in chelation therapy. Xerocytosis is a rare autosomal dominant genetic disorder characterized by dehydrated stomatocytosis. The patient may present with intense fatigue and iron overload. We suggest the regular use of T2* magnetic resonance imaging for the diagnosis and control of the response to iron chelation in xerocytosis, and we believe it can be used also in other hemolytic anemia requiring transfusions.

  5. Iron overload in a teenager with xerocytosis: the importance of nuclear magnetic resonance imaging.

    Science.gov (United States)

    Assis, Reijâne Alves de; Kassab, Carolina; Seguro, Fernanda Salles; Costa, Fernando Ferreira; Silveira, Paulo Augusto Achucarro; Wood, John; Hamerschlak, Nelson

    2013-12-01

    To report a case of iron overload secondary to xerocytosis, a rare disease in a teenager, diagnosed, by T2* magnetic resonance imaging. We report the case of a symptomatic patient with xerocytosis, a ferritin level of 350ng/mL and a significant cardiac iron overload. She was diagnosed by T2* magnetic resonance imaging and received chelation therapy Ektacytometric analysis confirmed the diagnosis of hereditary xerocytosis. Subsequent T2* magnetic resonance imaging demonstrated complete resolution of the iron overload in various organs, as a new echocardiography revealed a complete resolution of previous cardiac alterations. The patient remains in chelation therapy. Xerocytosis is a rare autosomal dominant genetic disorder characterized by dehydrated stomatocytosis. The patient may present with intense fatigue and iron overload. We suggest the regular use of T2* magnetic resonance imaging for the diagnosis and control of the response to iron chelation in xerocytosis, and we believe it can be used also in other hemolytic anemia requiring transfusions.

  6. Vacua of maximal gauged D=3 supergravities

    International Nuclear Information System (INIS)

    Fischbacher, T; Nicolai, H; Samtleben, H

    2002-01-01

    We analyse the scalar potentials of maximal gauged three-dimensional supergravities which reveal a surprisingly rich structure. In contrast to maximal supergravities in dimensions D≥4, all these theories possess a maximally supersymmetric (N=16) ground state with negative cosmological constant Λ 2 gauged theory, whose maximally supersymmetric groundstate has Λ = 0. We compute the mass spectra of bosonic and fermionic fluctuations around these vacua and identify the unitary irreducible representations of the relevant background (super)isometry groups to which they belong. In addition, we find several stationary points which are not maximally supersymmetric, and determine their complete mass spectra as well. In particular, we show that there are analogues of all stationary points found in higher dimensions, among them are de Sitter (dS) vacua in the theories with noncompact gauge groups SO(5, 3) 2 and SO(4, 4) 2 , as well as anti-de Sitter (AdS) vacua in the compact gauged theory preserving 1/4 and 1/8 of the supersymmetries. All the dS vacua have tachyonic instabilities, whereas there do exist nonsupersymmetric AdS vacua which are stable, again in contrast to the D≥4 theories

  7. Avaliação da frequência cardíaca à medida de pressão expiratória máxima estática e à manobra de Valsalva em jovens saudáveis Heart rate assessment during maximal static expiratory pressure and Valsalva maneuver in healthy young men

    Directory of Open Access Journals (Sweden)

    Vinicius Minatel

    2012-10-01

    Full Text Available CONTEXTUALIZAÇÃO: A medida de pressão expiratória máxima (PEmáx possui algumas contraindicações, pois acredita-se que as respostas obtidas nessa medida são similares às respostas encontradas na manobra de Valsalva (MV. OBJETIVOS: O objetivo principal é avaliar a resposta da frequência cardíaca (FC durante a medida da PEmáx e da MV em jovens saudáveis, em diferentes posturas, para identificar se e em qual condição a PEmáx reproduz as respostas obtidas na MV e, adicionalmente, estimar o trabalho realizado nas manobras. MÉTODO: Doze jovens saudáveis foram avaliados, orientados e familiarizados com as manobras. A MV foi composta por um esforço expiratório (40 mmHg durante 15 segundos contra um manômetro. A PEmáx foi executada segundo a American Thoracic Society. Ambas as medidas foram realizadas nas posturas supino e sentado. Para a análise da variação da frequência cardíaca (∆FC, índice de Valsalva (IV, índice da PEmáx (IPEmáx e o trabalho estimado das manobras (Wtotal, Wisotime, Wtotal/∆FCtotal e Wisotime/∆FCisotime , utilizou-se ANOVA two-way com post-hoc de Holm-Sidak (pBACKGROUND: The measure of the maximal expiratory pressure (MEP has some contraindications, as it is believed that the responses obtained in this measure are similar to the Valsalva maneuver (VM. OBJECTIVE: The main purpose of this study was to evaluate the heart rate responses (HR during the MEP and the VM measures in healthy young men into different postures aiming to identify whether and in which situation the MEP reproduces the responses obtained in the VM. Additionally we aim to estimate the workload realized during the maneuvers. METHOD: Twelve healthy young men were evaluated, instructed and familiarized with the maneuvers. The VM was characterized by an expiratory effort (40 mmHg against a manometer for 15 seconds. The MEP measure has been performed according to the American Thoracic Society. Both measures were performed at sitting

  8. I just want to be left alone: Daily overload and marital behavior.

    Science.gov (United States)

    Sears, Meredith S; Repetti, Rena L; Robles, Theodore F; Reynolds, Bridget M

    2016-08-01

    Stressful, busy days have been linked with increases in angry and withdrawn marital behavior. The process by which stressors in 1 domain, such as work, affect an individual’s behavior in another domain, such as the marital relationship, is known as spillover . Using 56 days of daily diary reports in a diverse sample of 47 wives and 39 husbands, this study examined associations between daily experiences of overload and 3 marital behaviors: overt expressions of anger, disregard of the spouse’s needs (“disregard”), and reductions in affection and disclosure (“distancing”). Two potential mechanisms by which daily overload spills over into marital behavior were examined: negative mood and the desire to avoid social interaction. Among husbands, negative mood mediated the association between overload and angry behavior. Associations between overload and wives’ angry behavior, as well as overload and husbands’ and wives’ disregard of their partners’ needs, were mediated by both negative mood and the desire to withdraw socially. Desire to withdraw, but not negative mood, mediated the association between overload and distancing behavior among husbands and wives. In addition, associations between marital satisfaction and spouses’ typical marital behavior, as well as behavioral responses to overload, were examined. Husbands’ and wives’ average levels of expressed anger and disregard, and husbands’ distancing, were associated with lower marital satisfaction in 1 or both partners. Both spouses reported lower marital satisfaction if husbands tended to express marital anger, disregard, or distancing on busy, overloaded days. PsycINFO Database Record (c) 2016 APA, all rights reserved

  9. Designing immersive surgical training against information technology-related overload in the operating room

    OpenAIRE

    Pluyter, J.R.

    2012-01-01

    On a theoretical level, this dissertation demonstrates that the “classical” conceptualization of overload in the field of Information Systems being an excessive amount of information is too simplistic. Based on the Emotional-Cognitive Overload Model by Rutkowski and Saunders (2011) this dissertation outlines the importance of the personal mental organization of Long-Term Memory (LTM) and the congruence of the information stimulus with cognitive schemata encoded in LTM.

  10. Over-exposed portraits : Technology overload and the identities of the young

    OpenAIRE

    Lutz, Christoph; Ranzini, Giulia; Meckel, Miriam

    2013-01-01

    Technostress and information overload represent serious challenges of the Information Age. An alarming number of people exhibit dangerously intensive media consumption, while Internet and mobile phone addictions are a widespread phenomenon, especially among teens. Despite increasing evidence for technostress and information overload within the literature, the consequences of new media overexposure on young individuals are so far understudied. When it comes to Social Network Sites (SNS), in pa...

  11. Work Overload and Turnover Intention of Junior Auditors in Greater Jakarta, Indonesia

    OpenAIRE

    Andika Pradana; Imam Salehudin

    2015-01-01

    This paper aims to analyze how work overload influences turnover intentions of newly hired junior auditors in public accounting offices. Job satisfaction, work related stress and work life conflicts are used as mediating variables between work overload and turnover intention. This study employed 141 auditors from several accounting firms operating in the Greater Jakarta region. The sample was selected using purposive sampling. Three mediation hypotheses were tested using Structural Equation M...

  12. Influence of subject choice, work overload and work stress on expatriate higher education teachers.

    OpenAIRE

    Naithani, Pranav

    2013-01-01

    Subject choice, work overload and work stress influence personal and professional lives of higher education teachers. Though the majority of higher education teachers in the Gulf Cooperation Council (GCC) countries are expatriates, yet research on expatriate higher education teachers working in the GCC countries is limited. This paper presents one part of the work life balance survey and focuses on the influence of subject choice, work overload and work stress on higher education teachers in ...

  13. Role overload, pain and physical dysfunction in early rheumatoid or undifferentiated inflammatory arthritis in Canada

    OpenAIRE

    Mustafa Sally; Looper Karl; Zelkowitz Phyllis; Purden Margaret; Baron Murray

    2012-01-01

    Abstract Background Inflammatory arthritis impairs participation in societal roles. Role overload arises when the demands by a given role set exceed the resources; time and energy, to carry out the required tasks. The present study examines the association between role overload and disease outcomes in early inflammatory arthritis (EIA). Methods Patients (n = 104) of 7.61 months mean duration of inflammatory arthritis completed self-report questionnaires on sociodemographics, disease character...

  14. Dangers of bypassing thermal overload relays in nuclear power plant motor operated valve circuits

    International Nuclear Information System (INIS)

    Baxter, F.D.

    1980-01-01

    Operation of motor operated valves is analyzed under various abnormal conditions such as frozen bearing, tight packing, mid-travel obstruction, torque switch failure, limit switch failure, and post-accident operation. Each condition has been reviewed to show that an adverse situation results if the thermal overload relays in the circuit are bypassed. In conclusion, there appears to be no technical basis for bypassing or oversizing the thermal overload relay provided it is selected correctly

  15. Cognitive overload and communication in two healthcare settings.

    Science.gov (United States)

    Cicourel, Aaron V

    2004-01-01

    The confluence of organizational social interaction and cognitive information processing constraints create 'noisy' conditions in institutionalized settings. Attentional and memory limitations always influence the ability of participants to comprehend each other's communication. Two organizational settings (a medical specialty clinic and periodontal office) will be used to explore a few features of healthcare delivery that are often ignored in studies of such systems. Scheduling appointments, for example, creates stress for both patients and healthcare personnel but is often an unexamined aspect of healthcare delivery that has become both challenging and often irritating for all concerned. For example, when patients call, someone at a general scheduling center or the particular clinic or office of an individual physician or dentist or a group practice will answer the call with a menu of options, or the caller may be asked to leave message. When a patient leaves a clinic or surgery office after a visit, they may be allowed to make a new appointment. The term 'cognitive overload' is a ubiquitous element of all healthcare systems and refers to organizationally induced and constrained limited capacity processing inherent in the way improvised discourse practices, and annotative devices or artifacts (such as written notes or some related strategy) become an integral part of everyday healthcare delivery.

  16. Overload and neovascularization of shoulder tendons in volleyball players

    Science.gov (United States)

    2012-01-01

    Background In overhead sports like volleyball, the onset of a rotator cuff tendinopathy due to functional overload is a common observation. An angiofibroblastic etiopathogenesis has been hypothesized, whereby a greater anaerobic metabolism occurs in critical zones of the tendon with a lower degree of vascularization; this would induce collagen and extracellular matrix degradation, that could then trigger a compensatory neovascularization response. We performed a clinical observational study of 80 elite volleyball players, monitoring the perfusion values of the supraspinatus tendons by oximetry. Results No statistically significant differences were found between the oximetry data and age, sex or years of sports activity, nor when comparing the right and left arm or the dominant and non-dominant arm. A statistically significant difference was found for the dominant arm values in relation to the competitive role, higher values being obtained in outside hitters (62.7%) than middle hitters (53.7%) (p = 0.01), opposite hitters (55.5%) (p = 0.02) and libero players (54.4%) (p = 0.008), whereas there were no differences in setters (56.2%) (p > 0.05). Conclusions The different tendon vascularization values found in players with different roles in the team may be attributed to a response to the specific biomechanical demands posed by the different overhead throwing roles. PMID:22853746

  17. Overload cascading failure on complex networks with heterogeneous load redistribution

    Science.gov (United States)

    Hou, Yueyi; Xing, Xiaoyun; Li, Menghui; Zeng, An; Wang, Yougui

    2017-09-01

    Many real systems including the Internet, power-grid and financial networks experience rare but large overload cascading failures triggered by small initial shocks. Many models on complex networks have been developed to investigate this phenomenon. Most of these models are based on the load redistribution process and assume that the load on a failed node shifts to nearby nodes in the networks either evenly or according to the load distribution rule before the cascade. Inspired by the fact that real power-grid tends to place the excess load on the nodes with high remaining capacities, we study a heterogeneous load redistribution mechanism in a simplified sandpile model in this paper. We find that weak heterogeneity in load redistribution can effectively mitigate the cascade while strong heterogeneity in load redistribution may even enlarge the size of the final failure. With a parameter θ to control the degree of the redistribution heterogeneity, we identify a rather robust optimal θ∗ = 1. Finally, we find that θ∗ tends to shift to a larger value if the initial sand distribution is homogeneous.

  18. Overload protection: avoidance response to heavy plantar surface loading.

    Science.gov (United States)

    Robbins, S E; Hanna, A M; Gouw, G J

    1988-02-01

    Current footwear which are designed for use in running are examples of intentional biomechanical model integration into device design. The inadequacy of this footwear in protecting against injury is postulated to be due to fixation on inadequate models of locomotory biomechanics that do not provide for feedback control; in particular, an hypothesized plantar surface sensory-mediated feedback control system, which imparts overload protection during locomotion. A heuristic approach was used to identify the hypothesized system. A random series of loads (0 to 164 kg) was applied to the knee flexed at 90 degrees. In this testing system, plantar surface avoidance behavior was the difference between the sum of the leg weight and the load applied to the knee, and the load measured at the plantar surface; this was produced by activation of hip flexors. Significant avoidance behavior was found in all of the subjects (P less than 0.001). On all surfaces tested, including modern athletic footwear (P less than 0.001), its magnitude increased directly in relation to the load applied to the knee (P less than 0.001). There were significant differences in avoidance behavior in relation to the weight-bearing surfaces tested (P less than 0.05). With the identification of a feedback control system which would serve to moderate loading during locomotion, an explanation is provided as to why current athletic footwear do not protect and may be injurious; thus allowing the design of footwear which may be truly protective.

  19. Performance Analysis of Novel Overload Control with Threshold Mechanism

    Directory of Open Access Journals (Sweden)

    Doo Il Choi

    2016-01-01

    Full Text Available We propose a novel overload control method with hysteresis property; that is, we analyze the M/G/1/K queueing system where the service and arrival rates are varied depending on the queue-length. We use two threshold values: L1(≤L2 and L2(≤K. When the queue-length increases by an amount between L1 and L2, we apply one of the following two strategies to reduce the queue-length, either we decrease the mean service time or we decrease the arrival rate. If the queue-length exceeds L2 with one strategy, we apply the other; thus, there are two models that depend on the method that was applied first. We derive the queue-length distribution at departure and at arbitrary epochs using the embedded Markov chain method and the supplementary variable method. We investigate performance measures including the loss probability and mean waiting time using various numerical examples.

  20. An information maximization model of eye movements

    Science.gov (United States)

    Renninger, Laura Walker; Coughlan, James; Verghese, Preeti; Malik, Jitendra

    2005-01-01

    We propose a sequential information maximization model as a general strategy for programming eye movements. The model reconstructs high-resolution visual information from a sequence of fixations, taking into account the fall-off in resolution from the fovea to the periphery. From this framework we get a simple rule for predicting fixation sequences: after each fixation, fixate next at the location that minimizes uncertainty (maximizes information) about the stimulus. By comparing our model performance to human eye movement data and to predictions from a saliency and random model, we demonstrate that our model is best at predicting fixation locations. Modeling additional biological constraints will improve the prediction of fixation sequences. Our results suggest that information maximization is a useful principle for programming eye movements.

  1. Utility Maximization in Nonconvex Wireless Systems

    CERN Document Server

    Brehmer, Johannes

    2012-01-01

    This monograph formulates a framework for modeling and solving utility maximization problems in nonconvex wireless systems. First, a model for utility optimization in wireless systems is defined. The model is general enough to encompass a wide array of system configurations and performance objectives. Based on the general model, a set of methods for solving utility maximization problems is developed. The development is based on a careful examination of the properties that are required for the application of each method. The focus is on problems whose initial formulation does not allow for a solution by standard convex methods. Solution approaches that take into account the nonconvexities inherent to wireless systems are discussed in detail. The monograph concludes with two case studies that demonstrate the application of the proposed framework to utility maximization in multi-antenna broadcast channels.

  2. Interactions of Aging, Overload, and Creatine Supplementation in Rat Plantaris Muscle

    Directory of Open Access Journals (Sweden)

    Mark D. Schuenke

    2011-01-01

    Full Text Available Attenuation of age-related sarcopenia by creatine supplementation has been equivocal. In this study, plantaris muscles of young (Y; 5m and aging (A; 24m Fisher 344 rats underwent four weeks of either control (C, creatine supplementation (Cr, surgical overload (O, or overload plus creatine (OCr. Creatine alone had no effect on muscle fiber cross-sectional area (CSA or heat shock protein (HSP70 and increased myonuclear domain (MND only in young rats. Overload increased CSA and HSP70 content in I and IIA fibers, regardless of age, and MND in IIA fibers of YO rats. CSA and MND increased in all fast fibers of YOCr, and CSA increased in I and IIA fibers of AOCr. OCR did not alter HSP70, regardless of age. MND did not change in aging rats, regardless of treatment. These data indicate creatine alone had no significant effect. Creatine with overload produced no additional hypertrophy relative to overload alone and attenuated overload-induced HSP70 expression.

  3. When more is less: An examination of the relationship between hours in telework and role overload.

    Science.gov (United States)

    Duxbury, Linda; Halinski, Michael

    2014-01-01

    Proponents of telework arrangements assert that those who telework have more control over their work and family domains than their counterparts who are not permitted to work from home. Using Karasek's theory we hypothesized that the relationship between demands (hours in work per week; hours in childcare per week) and strain (work role overload; family role overload) would be moderated by the number of hours the employee spent per week teleworking (control). To determine how the number of telework hours relates to work role overload and family role overload, we follow the test for moderation and mediation using hierarchical multiple regression analysis as outlined by Frazier et al. [50] We used survey data collected from 1,806 male and female professional employees who spent at least one hour per week working from home during regular hours (i.e. teleworking). As hypothesized, the number of hours in telework per week negatively moderated the relation between work demands (total hours in paid employment per week) and work strain (work role overload). Contrary to our hypothesis, the number of hours in telework per week only partially mediated the relation between family demands (hours a week in childcare) and family role overload (strain). The findings from this study support the idea that the control offered by telework is domain specific (helps employees meet demands at work but not at home).

  4. Influence of overloads on dwell time fatigue crack growth in Inconel 718

    Energy Technology Data Exchange (ETDEWEB)

    Saarimäki, Jonas, E-mail: jonas.saarimaki@liu.se [Division of Engineering Materials, Department of Management and Engineering, Linköping University, SE-58183 Linköping (Sweden); Moverare, Johan [Division of Engineering Materials, Department of Management and Engineering, Linköping University, SE-58183 Linköping (Sweden); Siemens Industrial Turbomachinery AB, Materials Technology, SE-61283 Finspång (Sweden); Eriksson, Robert; Johansson, Sten [Division of Engineering Materials, Department of Management and Engineering, Linköping University, SE-58183 Linköping (Sweden)

    2014-08-26

    Inconel 718 is one of the most commonly used superalloys for high temperature applications in gasturbines and aeroengines and is for example used for components such as turbine discs. Turbine discs can be subjected to temperatures up to ∼700 °C towards the outer radius of the disc. During service, the discs might start to develop cracks due to fatigue and long dwell times. Additionally, temperature variations during use can lead to large thermal transients during start-up and shutdown which can lead to overload peaks in the normal dwell time cycle. In this study, tests at 550 °C with an overload prior to the start of each dwell time, have been performed. The aim of the investigation was to get a better understanding of the effects of overloads on the microstructure and crack mechanisms. The microstructure was studied using electron channelling contrast imaging (ECCI). The image analysis toolbox in Matlab was used on cross sections of the cracks to quantify: crack length, branch length, and the number of branches in each crack. It was found that the amount of crack branching increases with an increasing overload and that the branch length decreases with an increasing overload. When the higher overloads were applied, the dwell time effect was almost cancelled out. There is a strong tendency for an increased roughness of the crack path with an increasing crack growth rate.

  5. Influence of overloads on dwell time fatigue crack growth in Inconel 718

    International Nuclear Information System (INIS)

    Saarimäki, Jonas; Moverare, Johan; Eriksson, Robert; Johansson, Sten

    2014-01-01

    Inconel 718 is one of the most commonly used superalloys for high temperature applications in gasturbines and aeroengines and is for example used for components such as turbine discs. Turbine discs can be subjected to temperatures up to ∼700 °C towards the outer radius of the disc. During service, the discs might start to develop cracks due to fatigue and long dwell times. Additionally, temperature variations during use can lead to large thermal transients during start-up and shutdown which can lead to overload peaks in the normal dwell time cycle. In this study, tests at 550 °C with an overload prior to the start of each dwell time, have been performed. The aim of the investigation was to get a better understanding of the effects of overloads on the microstructure and crack mechanisms. The microstructure was studied using electron channelling contrast imaging (ECCI). The image analysis toolbox in Matlab was used on cross sections of the cracks to quantify: crack length, branch length, and the number of branches in each crack. It was found that the amount of crack branching increases with an increasing overload and that the branch length decreases with an increasing overload. When the higher overloads were applied, the dwell time effect was almost cancelled out. There is a strong tendency for an increased roughness of the crack path with an increasing crack growth rate

  6. Effects of intracellular iron overload on cell death and identification of potent cell death inhibitors.

    Science.gov (United States)

    Fang, Shenglin; Yu, Xiaonan; Ding, Haoxuan; Han, Jianan; Feng, Jie

    2018-06-11

    Iron overload causes many diseases, while the underlying etiologies of these diseases are unclear. Cell death processes including apoptosis, necroptosis, cyclophilin D-(CypD)-dependent necrosis and a recently described additional form of regulated cell death called ferroptosis, are dependent on iron or iron-dependent reactive oxygen species (ROS). However, whether the accumulation of intracellular iron itself induces ferroptosis or other forms of cell death is largely elusive. In present study, we study the role of intracellular iron overload itself-induced cell death mechanisms by using ferric ammonium citrate (FAC) and a membrane-permeable Ferric 8-hydroxyquinoline complex (Fe-8HQ) respectively. We show that FAC-induced intracellular iron overload causes ferroptosis. We also identify 3-phosphoinositide-dependent kinase 1 (PDK1) inhibitor GSK2334470 as a potent ferroptosis inhibitor. Whereas, Fe-8HQ-induced intracellular iron overload causes unregulated necrosis, but partially activates PARP-1 dependent parthanatos. Interestingly, we identify many phenolic compounds as potent inhibitors of Fe-8HQ-induced cell death. In conclusion, intracellular iron overload-induced cell death form might be dependent on the intracellular iron accumulation rate, newly identified cell death inhibitors in our study that target ferroptosis and unregulated oxidative cell death represent potential therapeutic strategies against iron overload related diseases. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Effect of overloading types on fatigue crack growth threshold for stainless steel SUS316

    International Nuclear Information System (INIS)

    Osada, Toshio; Sano, Hayato; Takahashi, Koji

    2013-01-01

    Effect of overloading types on the fatigue crack growth threshold of SUS316 was studied. Three types of overloading: tensile (type I), tensile+compression (type II), and tensile+compression+tensile (type III) were applied to compact tension specimens, then the fatigue tests were carried out to determine the apparent threshold stress intensity factor range Δ N K th . The results showed that the Δ N K th values increased with increasing the single tensile overload stress intensity factor K ov above the K ov > ΔK th . Additional compressive loading (type II) led to decrease in Δ N K th to the ΔK th =6MPa×m 1/2 within the all tested K ov values ranging from -45MPa×m 1/2 ≤K ov 1/2 . This is due to the fact that the compressive residual stress field at crack tip changed to the tensile stress field by the compressive loading. Furthermore, the Δ N K th values increased again by additional tensile overloading (type III) from ΔK th to the almost same Δ N K th values as that by Type I loading. This means that the almost same compressive residual stress field formed by type III overloading as the type I overloading. The experimental Δ N K th increasing behaviors were discussed by Finite Element Method (FEM). (author)

  8. Pharmacokinetics study of Zr-89-labeled melanin nanoparticle in iron-overload mice

    International Nuclear Information System (INIS)

    Zhang, Pengjun; Yue, Yuanyuan; Pan, Donghui; Yang, Runlin; Xu, Yuping; Wang, Lizhen; Yan, Junjie; Li, Xiaotian; Yang, Min

    2016-01-01

    Melanin, a natural biological pigment present in many organisms, has been found to exhibit multiple functions. An important property of melanin is its ability to chelate metal ions strongly, which might be developed as an iron chelator for iron overload therapy. Herein, we prepared the ultrasmall water-soluble melanin nanoparticle (MP) and firstly evaluate the pharmacokinetics of MP in iron-overload mice to provide scientific basis for treating iron-overload. To study the circulation time and biodistribution, MP was labeled with 89 Zr, a long half-life (78.4 h) positron-emitting metal which is suited for the labeling of nanoparticles and large bioactive molecule. MP was chelated with 89 Zr directly at pH 5, resulting in non-decay-corrected yield of 89.6% and a radiochemical purity of more than 98%. The specific activity was at least190 MBq/μmol. The 89 Zr-MP was stable in human plasma and PBS for at least 48 h. The half-life of 89 Zr-MP was about 15.70 ± 1.74 h in iron-overload mice. Biodistribution studies and MicroPET imaging showed that 89 Zr-MP mainly accumulated in liver and spleen, which are the target organ of iron-overload. The results indicate that the melanin nanoparticle is promising for further iron overload therapy.

  9. Differential requirement for satellite cells during overload-induced muscle hypertrophy in growing versus mature mice.

    Science.gov (United States)

    Murach, Kevin A; White, Sarah H; Wen, Yuan; Ho, Angel; Dupont-Versteegden, Esther E; McCarthy, John J; Peterson, Charlotte A

    2017-07-10

    Pax7+ satellite cells are required for skeletal muscle fiber growth during post-natal development in mice. Satellite cell-mediated myonuclear accretion also appears to persist into early adulthood. Given the important role of satellite cells during muscle development, we hypothesized that the necessity of satellite cells for adaptation to an imposed hypertrophic stimulus depends on maturational age. Pax7 CreER -R26R DTA mice were treated for 5 days with vehicle (satellite cell-replete, SC+) or tamoxifen (satellite cell-depleted, SC-) at 2 months (young) and 4 months (mature) of age. Following a 2-week washout, mice were subjected to sham surgery or 10 day synergist ablation overload of the plantaris (n = 6-9 per group). The surgical approach minimized regeneration, de novo fiber formation, and fiber splitting while promoting muscle fiber growth. Satellite cell density (Pax7+ cells/fiber), embryonic myosin heavy chain expression (eMyHC), and muscle fiber cross sectional area (CSA) were evaluated via immunohistochemistry. Myonuclei (myonuclei/100 mm) were counted on isolated single muscle fibers. Tamoxifen treatment depleted satellite cells by ≥90% and prevented myonuclear accretion with overload in young and mature mice (p overload. Average muscle fiber CSA increased ~20% in young SC+ (p = 0.07), mature SC+ (p overload (p overload-induced hypertrophy is dependent on maturational age, and global responses to overload differ in young versus mature mice.

  10. Secoisolariciresinol diglucoside abrogates oxidative stress-induced damage in cardiac iron overload condition.

    Directory of Open Access Journals (Sweden)

    Stephanie Puukila

    Full Text Available Cardiac iron overload is directly associated with cardiac dysfunction and can ultimately lead to heart failure. This study examined the effect of secoisolariciresinol diglucoside (SDG, a component of flaxseed, on iron overload induced cardiac damage by evaluating oxidative stress, inflammation and apoptosis in H9c2 cardiomyocytes. Cells were incubated with 50 μ5M iron for 24 hours and/or a 24 hour pre-treatment of 500 μ M SDG. Cardiac iron overload resulted in increased oxidative stress and gene expression of the inflammatory mediators tumor necrosis factor-α, interleukin-10 and interferon γ, as well as matrix metalloproteinases-2 and -9. Increased apoptosis was evident by increased active caspase 3/7 activity and increased protein expression of Forkhead box O3a, caspase 3 and Bax. Cardiac iron overload also resulted in increased protein expression of p70S6 Kinase 1 and decreased expression of AMP-activated protein kinase. Pre-treatment with SDG abrogated the iron-induced increases in oxidative stress, inflammation and apoptosis, as well as the increased p70S6 Kinase 1 and decreased AMP-activated protein kinase expression. The decrease in superoxide dismutase activity by iron treatment was prevented by pre-treatment with SDG in the presence of iron. Based on these findings we conclude that SDG was cytoprotective in an in vitro model of iron overload induced redox-inflammatory damage, suggesting a novel potential role for SDG in cardiac iron overload.

  11. Plasma insulin levels are increased by sertraline in rats under oral glucose overload

    Directory of Open Access Journals (Sweden)

    Gomez R.

    2001-01-01

    Full Text Available Recognition and control of depression symptoms are important to increase patient compliance with treatment and to improve the quality of life of diabetic patients. Clinical studies indicate that selective serotonin reuptake inhibitors (SSRI are better antidepressants for diabetic patients than other drugs. However, preclinical trials have demonstrated that not all SSRI reduce plasma glucose levels. In fact, fluoxetine increases and sertraline decreases glycemia in diabetic and non-diabetic rats. In the present study we evaluated plasma insulin levels during fasting and after glucose overload after treatment with sertraline. Adult male Wistar rats were fasted and treated with saline or 30 mg/kg sertraline and submitted or not to glucose overload (N = 10. Blood was collected and plasma insulin was measured. The mean insulin levels were: fasting group: 25.9 ± 3.86, sertraline + fasting group: 31.10 ± 2.48, overload group: 34.1 ± 3.40, and overload + sertraline group: 43.73 ± 5.14 µU/ml. Insulinemia was significantly increased in the overload + sertraline group. There were no differences between the other groups. No difference in glucose/insulin ratios could be detected between groups. The overload + sertraline group was the only one in which a significant number of individuals exceeded the upper confidence limit of insulin levels. This study demonstrates that sertraline increases glucose-stimulated insulin secretion without any change in peripheral insulin sensitivity.

  12. Maximizing band gaps in plate structures

    DEFF Research Database (Denmark)

    Halkjær, Søren; Sigmund, Ole; Jensen, Jakob Søndergaard

    2006-01-01

    periodic plate using Bloch theory, which conveniently reduces the maximization problem to that of a single base cell. Secondly, we construct a finite periodic plate using a number of the optimized base cells in a postprocessed version. The dynamic properties of the finite plate are investigated......Band gaps, i.e., frequency ranges in which waves cannot propagate, can be found in elastic structures for which there is a certain periodic modulation of the material properties or structure. In this paper, we maximize the band gap size for bending waves in a Mindlin plate. We analyze an infinite...... theoretically and experimentally and the issue of finite size effects is addressed....

  13. Singularity Structure of Maximally Supersymmetric Scattering Amplitudes

    DEFF Research Database (Denmark)

    Arkani-Hamed, Nima; Bourjaily, Jacob L.; Cachazo, Freddy

    2014-01-01

    We present evidence that loop amplitudes in maximally supersymmetric (N=4) Yang-Mills theory (SYM) beyond the planar limit share some of the remarkable structures of the planar theory. In particular, we show that through two loops, the four-particle amplitude in full N=4 SYM has only logarithmic ...... singularities and is free of any poles at infinity—properties closely related to uniform transcendentality and the UV finiteness of the theory. We also briefly comment on implications for maximal (N=8) supergravity theory (SUGRA)....

  14. Learning curves for mutual information maximization

    International Nuclear Information System (INIS)

    Urbanczik, R.

    2003-01-01

    An unsupervised learning procedure based on maximizing the mutual information between the outputs of two networks receiving different but statistically dependent inputs is analyzed [S. Becker and G. Hinton, Nature (London) 355, 161 (1992)]. For a generic data model, I show that in the large sample limit the structure in the data is recognized by mutual information maximization. For a more restricted model, where the networks are similar to perceptrons, I calculate the learning curves for zero-temperature Gibbs learning. These show that convergence can be rather slow, and a way of regularizing the procedure is considered

  15. Finding Maximal Pairs with Bounded Gap

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Lyngsø, Rune B.; Pedersen, Christian N. S.

    1999-01-01

    . In this paper we present methods for finding all maximal pairs under various constraints on the gap. In a string of length n we can find all maximal pairs with gap in an upper and lower bounded interval in time O(n log n+z) where z is the number of reported pairs. If the upper bound is removed the time reduces...... to O(n+z). Since a tandem repeat is a pair where the gap is zero, our methods can be seen as a generalization of finding tandem repeats. The running time of our methods equals the running time of well known methods for finding tandem repeats....

  16. Hemodynamic and arterial stiffness differences between African-Americans and Caucasians after maximal exercise.

    Science.gov (United States)

    Yan, Huimin; Ranadive, Sushant M; Heffernan, Kevin S; Lane, Abbi D; Kappus, Rebecca M; Cook, Marc D; Wu, Pei-Tzu; Sun, Peng; Harvey, Idethia S; Woods, Jeffrey A; Wilund, Kenneth R; Fernhall, Bo

    2014-01-01

    African-American (AA) men have higher arterial stiffness and augmentation index (AIx) than Caucasian-American (CA) men. Women have greater age-associated increases in arterial stiffness and AIx than men. This study examined racial and sex differences in arterial stiffness and central hemodynamics at rest and after an acute bout of maximal exercise in young healthy individuals. One hundred young, healthy individuals (28 AA men, 24 AA women, 25 CA men, and 23 CA women) underwent measurements of aortic blood pressure (BP) and arterial stiffness at rest and 15 and 30 min after an acute bout of graded maximal aerobic exercise. Aortic BP and AIx were derived from radial artery applanation tonometry. Aortic stiffness (carotid-femoral) was measured via pulse wave velocity. Aortic stiffness was increased in AA subjects but not in CA subjects (P < 0.05) after an acute bout of maximal cycling exercise, after controlling for body mass index. Aortic BP decreased after exercise in CA subjects but not in AA subjects (P < 0.05). Women exhibited greater reductions in AIx after maximal aerobic exercise compared with men (P < 0.05). In conclusion, race and sex impact vascular and central hemodynamic responses to exercise. Young AA and CA subjects exhibited differential responses in central stiffness and central BP after acute maximal exercise. Premenopausal women had greater augmented pressure at rest and after maximal aerobic exercise than men. Future research is needed to examine the potential mechanisms.

  17. Maximizing the Range of a Projectile.

    Science.gov (United States)

    Brown, Ronald A.

    1992-01-01

    Discusses solutions to the problem of maximizing the range of a projectile. Presents three references that solve the problem with and without the use of calculus. Offers a fourth solution suitable for introductory physics courses that relies more on trigonometry and the geometry of the problem. (MDH)

  18. Robust Utility Maximization Under Convex Portfolio Constraints

    International Nuclear Information System (INIS)

    Matoussi, Anis; Mezghani, Hanen; Mnif, Mohamed

    2015-01-01

    We study a robust maximization problem from terminal wealth and consumption under a convex constraints on the portfolio. We state the existence and the uniqueness of the consumption–investment strategy by studying the associated quadratic backward stochastic differential equation. We characterize the optimal control by using the duality method and deriving a dynamic maximum principle

  19. Ehrenfest's Lottery--Time and Entropy Maximization

    Science.gov (United States)

    Ashbaugh, Henry S.

    2010-01-01

    Successful teaching of the Second Law of Thermodynamics suffers from limited simple examples linking equilibrium to entropy maximization. I describe a thought experiment connecting entropy to a lottery that mixes marbles amongst a collection of urns. This mixing obeys diffusion-like dynamics. Equilibrium is achieved when the marble distribution is…

  20. Reserve design to maximize species persistence

    Science.gov (United States)

    Robert G. Haight; Laurel E. Travis

    2008-01-01

    We develop a reserve design strategy to maximize the probability of species persistence predicted by a stochastic, individual-based, metapopulation model. Because the population model does not fit exact optimization procedures, our strategy involves deriving promising solutions from theory, obtaining promising solutions from a simulation optimization heuristic, and...

  1. Maximal indecomposable past sets and event horizons

    International Nuclear Information System (INIS)

    Krolak, A.

    1984-01-01

    The existence of maximal indecomposable past sets MIPs is demonstrated using the Kuratowski-Zorn lemma. A criterion for the existence of an absolute event horizon in space-time is given in terms of MIPs and a relation to black hole event horizon is shown. (author)

  2. Maximization of eigenvalues using topology optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2000-01-01

    to localized modes in low density areas. The topology optimization problem is formulated using the SIMP method. Special attention is paid to a numerical method for removing localized eigenmodes in low density areas. The method is applied to numerical examples of maximizing the first eigenfrequency, One example...

  3. Maximizing Resource Utilization in Video Streaming Systems

    Science.gov (United States)

    Alsmirat, Mohammad Abdullah

    2013-01-01

    Video streaming has recently grown dramatically in popularity over the Internet, Cable TV, and wire-less networks. Because of the resource demanding nature of video streaming applications, maximizing resource utilization in any video streaming system is a key factor to increase the scalability and decrease the cost of the system. Resources to…

  4. A THEORY OF MAXIMIZING SENSORY INFORMATION

    NARCIS (Netherlands)

    Hateren, J.H. van

    1992-01-01

    A theory is developed on the assumption that early sensory processing aims at maximizing the information rate in the channels connecting the sensory system to more central parts of the brain, where it is assumed that these channels are noisy and have a limited dynamic range. Given a stimulus power

  5. Maximizing scientific knowledge from randomized clinical trials

    DEFF Research Database (Denmark)

    Gustafsson, Finn; Atar, Dan; Pitt, Bertram

    2010-01-01

    Trialists have an ethical and financial responsibility to plan and conduct clinical trials in a manner that will maximize the scientific knowledge gained from the trial. However, the amount of scientific information generated by randomized clinical trials in cardiovascular medicine is highly vari...

  6. A Model of College Tuition Maximization

    Science.gov (United States)

    Bosshardt, Donald I.; Lichtenstein, Larry; Zaporowski, Mark P.

    2009-01-01

    This paper develops a series of models for optimal tuition pricing for private colleges and universities. The university is assumed to be a profit maximizing, price discriminating monopolist. The enrollment decision of student's is stochastic in nature. The university offers an effective tuition rate, comprised of stipulated tuition less financial…

  7. Logit Analysis for Profit Maximizing Loan Classification

    OpenAIRE

    Watt, David L.; Mortensen, Timothy L.; Leistritz, F. Larry

    1988-01-01

    Lending criteria and loan classification methods are developed. Rating system breaking points are analyzed to present a method to maximize loan revenues. Financial characteristics of farmers are used as determinants of delinquency in a multivariate logistic model. Results indicate that debt-to-asset and operating ration are most indicative of default.

  8. Does information overload prevent chronic patients from reading self-management educational materials?

    Science.gov (United States)

    Liu, Chung-Feng; Kuo, Kuang-Ming

    2016-05-01

    Self-care management is becoming an important part of care for chronic patients. However, various kinds of self-management educational materials which government or healthcare institutions provide for patients may not achieve the expected outcome. One of the critical reasons affecting patients' use intention could be patients' perceived information overload regarding the self-management educational materials. This study proposed an extended model of the Theory of Planned Behavior (TPB), which incorporated perceived information overload, to explore if information overload will prevent chronic patients from reading educational materials for self-care management. The independent variables are attitude, subject norm, perceived behavior control and perceived information overload while the dependent variable is behavior intention to use the self-management educational materials. Perceived information overload is also referred to as an antecedent variable which may has impacts on attitude and perceived behavior control. The cross-sectional study interviewed newly diagnosed chronic patients with coronary artery disease, who are the potential users of the self-management educational materials, in a medical center in Taiwan. Data were analyzed using descriptive statistics of the basic information distribution of the respondents, and structural equation modeling to study the reliability and validity for testing hypotheses. A total of 110 respondents were enrolled in this study and successful interview data were collected from 106 respondents. The result indicates that the patients' perceived information overload of self-management educational materials was validated to have impacts on attitude and perceived behavioral control constructs of the TPB as well as contributing a direct impact on patients' intentions to use self-management educational materials. Besides, subjective norm and perceived behavioral control constructs were validated to have significant impacts on

  9. Developing maximal neuromuscular power: Part 1--biological basis of maximal power production.

    Science.gov (United States)

    Cormie, Prue; McGuigan, Michael R; Newton, Robert U

    2011-01-01

    This series of reviews focuses on the most important neuromuscular function in many sport performances, the ability to generate maximal muscular power. Part 1 focuses on the factors that affect maximal power production, while part 2, which will follow in a forthcoming edition of Sports Medicine, explores the practical application of these findings by reviewing the scientific literature relevant to the development of training programmes that most effectively enhance maximal power production. The ability of the neuromuscular system to generate maximal power is affected by a range of interrelated factors. Maximal muscular power is defined and limited by the force-velocity relationship and affected by the length-tension relationship. The ability to generate maximal power is influenced by the type of muscle action involved and, in particular, the time available to develop force, storage and utilization of elastic energy, interactions of contractile and elastic elements, potentiation of contractile and elastic filaments as well as stretch reflexes. Furthermore, maximal power production is influenced by morphological factors including fibre type contribution to whole muscle area, muscle architectural features and tendon properties as well as neural factors including motor unit recruitment, firing frequency, synchronization and inter-muscular coordination. In addition, acute changes in the muscle environment (i.e. alterations resulting from fatigue, changes in hormone milieu and muscle temperature) impact the ability to generate maximal power. Resistance training has been shown to impact each of these neuromuscular factors in quite specific ways. Therefore, an understanding of the biological basis of maximal power production is essential for developing training programmes that effectively enhance maximal power production in the human.

  10. Understanding Violations of Gricean Maxims in Preschoolers and Adults

    Directory of Open Access Journals (Sweden)

    Mako eOkanda

    2015-07-01

    Full Text Available This study used a revised Conversational Violations Test to examine Gricean maxim violations in 4- to 6-year-old Japanese children and adults. Participants’ understanding of the following maxims was assessed: be informative (first maxim of quantity, avoid redundancy (second maxim of quantity, be truthful (maxim of quality, be relevant (maxim of relation, avoid ambiguity (second maxim of manner, and be polite (maxim of politeness. Sensitivity to violations of Gricean maxims increased with age: 4-year-olds’ understanding of maxims was near chance, 5-year-olds understood some maxims (first maxim of quantity and maxims of quality, relation, and manner, and 6-year-olds and adults understood all maxims. Preschoolers acquired the maxim of relation first and had the greatest difficulty understanding the second maxim of quantity. Children and adults differed in their comprehension of the maxim of politeness. The development of the pragmatic understanding of Gricean maxims and implications for the construction of developmental tasks from early childhood to adulthood are discussed.

  11. Electrical short circuit and current overload tests on aircraft wiring

    Science.gov (United States)

    Cahill, Patricia

    1995-01-01

    The findings of electrical short circuit and current overload tests performed on commercial aircraft wiring are presented. A series of bench-scale tests were conducted to evaluate circuit breaker response to overcurrent and to determine if the wire showed any visible signs of thermal degradation due to overcurrent. Three types of wire used in commercial aircraft were evaluated: MIL-W-22759/34 (150 C rated), MIL-W-81381/12 (200 C rated), and BMS 1360 (260 C rated). A second series of tests evaluated circuit breaker response to short circuits and ticking faults. These tests were also meant to determine if the three test wires behaved differently under these conditions and if a short circuit or ticking fault could start a fire. It is concluded that circuit breakers provided reliable overcurrent protection. Circuit breakers may not protect wire from ticking faults but can protect wire from direct shorts. These tests indicated that the appearance of a wire subjected to a current that totally degrades the insulation looks identical to a wire subjected to a fire; however the 'fire exposed' conductor was more brittle than the conductor degraded by overcurrent. Preliminary testing indicates that direct short circuits are not likely to start a fire. Preliminary testing indicated that direct short circuits do not erode insulation and conductor to the extent that ticking faults did. Circuit breakers may not safeguard against the ignition of flammable materials by ticking faults. The flammability of materials near ticking faults is far more important than the rating of the wire insulation material.

  12. The attenuating effect of role overload on relationships linking self-efficacy and goal level to work performance.

    Science.gov (United States)

    Brown, Steven P; Jones, Eli; Leigh, Thomas W

    2005-09-01

    The reported research examines the moderating effects of role overload on the antecedents and consequences of self-efficacy and personal goal level in a longitudinal study conducted in an industrial selling context. The results indicate that role overload moderates the antecedent effect of perceived organizational resources on self-efficacy beliefs. They also show that role overload moderates the direct effects of both self-efficacy and goal level on performance, such that these relationships are positive when role overload is low but not significant when role overload is high. Further, the results reveal a pattern of moderated mediation, in which goal level mediates the indirect effect of self-efficacy on performance when role overload is low but not when it is high. Implications for theory and managerial practice are discussed. Copyright 2005 APA, all rights reserved.

  13. Functional and Muscle-Size Effects of Flywheel Resistance Training with Eccentric-Overload in Professional Handball Players.

    Science.gov (United States)

    Maroto-Izquierdo, Sergio; García-López, David; de Paz, José A

    2017-12-01

    The aim of the study was to analyse the effects of 6 week (15 sessions) flywheel resistance training with eccentric-overload (FRTEO) on different functional and anatomical variables in professional handball players. Twenty-nine athletes were recruited and randomly divided into two groups. The experimental group (EXP, n = 15) carried out 15 sessions of FRTEO in the leg-press exercise, with 4 sets of 7 repetitions at a maximum-concentric effort. The control group (CON, n = 14) performed the same number of training sessions including 4 sets of 7 maximum repetitions (7RM) using a weight-stack leg-press machine. The results which were measured included maximal dynamic strength (1RM), muscle power at different submaximal loads (PO), vertical jump height (CMJ and SJ), 20 m sprint time (20 m), T-test time (T-test), and Vastus-Lateralis muscle (VL) thickness. The results of the EXP group showed a substantially better improvement (p handball requires repeated short, explosive effort such as accelerations and decelerations during sprints with changes of direction, these results suggest that FRTEO affects functional and anatomical changes in a way which improves performance in well-trained professional handball players.

  14. Clinical outcomes of transfusion-associated iron overload in patients with refractory chronic anemia

    Directory of Open Access Journals (Sweden)

    Gao C

    2014-04-01

    Full Text Available Chong Gao, Li Li, Baoan Chen, Huihui Song, Jian Cheng, Xiaoping Zhang, Yunyu SunDepartment of Hematology and Oncology, Key Department of Jiangsu Medicine, Zhongda Hospital, Medical School, Southeast University, Nanjing, Jiangsu Province, People’s Republic of ChinaBackground: The purpose of this study was to evaluate the clinical outcomes of transfusion-associated iron overload in patients with chronic refractory anemia.Methods: Clinical manifestations, main organ function, results of computed tomography (CT, endocrine evaluation, and serum ferritin levels were analyzed retrospectively in 13 patients who were transfusion-dependent for more than 1 year (receiving >50 units of red blood cells to determine the degree of iron overload and efficacy of iron-chelating therapy.Results: Serum ferritin levels increased to 1,830–5,740 ng/mL in all patients. Ten patients had abnormal liver function. The CT Hounsfield units in the liver increased significantly in eleven patients, and were proportional to their serum ferritin levels. Skin pigmentation, liver dysfunction, and endocrine dysfunction were observed in nine patients with serum ferritin >3,500 ng/mL, eight of whom have since died. Interestingly, serum ferritin levels did not decrease significantly in nine transfusion-dependent patients who had received 15–60 days of iron-chelating therapy.Conclusion: Transfusion-dependent patients may progress to secondary iron overload with organ impairment, which may be fatal in those who are heavily iron-overloaded. The CT Hounsfield unit is a sensitive indicator of iron overload in the liver. Iron chelation therapy should be initiated when serum ferritin is >1,000 ng/mL and continued until it is <1,000 ng/mL in transfusional iron-overloaded patients.Keywords: anemia, aplastic, iron overload, myelodysplastic syndromes

  15. The Family in Care for the Elderly: Managing the Overload and Coping with Difficulties

    Directory of Open Access Journals (Sweden)

    Lisete dos Santos Mendes Mónico

    2017-08-01

    Full Text Available Introduction: Family is considered the main support of the elderly in a situation of dependency. Caregiving often results in overloading, leading to diverse problems. Aim: To evaluate the self-perception of the family caregiver’s overload and the strategies used to provide informal care to the dependent elderly considering their level of dependence. Method: The sample consisted of 21 children, 16 spouses, and nine other relatives of elderly dependents who responded to the Caregiver’s Overload Scale (Sequeira, 2007, the Portuguese version of Caregivers’ Assessment Management Index (CAMI, Nolan, Keady, & Grant, 1995 and the Barthel Index (Mahoney & Barthel, 1965. Results: The Barthel Index showed 34.8% of the elderly as severely dependent and 37.0% as totally dependent. The care most provided respected to medication, hygiene, food, and monitoring. Above 56.5% of the caregivers had an intense overload, both at the objective (impact of care and interpersonal relationship and subjective (F3-Expectations regarding care and F4-Perceived self-efficacy levels. The main reason for maintaining caregivers was family/personal obligation (95.7%. Caregivers reasonably assessed the effectiveness of their strategies in dealing with their dependent elderly (CAMI; M = 101.0, SD = 15.0. There was a negative relationship between the perception of the caregiver’s overload and the age and health status of the elderly, as well as between the number of strategies used by the caregiver to overcome difficulties and the self-perception of the overload. Conclusion: The multiplicity of daily tasks performed in support of a family member in a situation of severe dependence translates into situations of intense overload, negatively impacting on care, interpersonal relationship, expectations regarding caring, and perception of self-efficacy of care.

  16. Efferent pathways in sodium overload-induced renal vasodilation in rats.

    Directory of Open Access Journals (Sweden)

    Nathalia O Amaral

    Full Text Available Hypernatremia stimulates the secretion of oxytocin (OT, but the physiological role of OT remains unclear. The present study sought to determine the involvement of OT and renal nerves in the renal responses to an intravenous infusion of hypertonic saline. Male Wistar rats (280-350 g were anesthetized with sodium thiopental (40 mg. kg(-1, i.v.. A bladder cannula was implanted for collection of urine. Animals were also instrumented for measurement of mean arterial pressure (MAP and renal blood flow (RBF. Renal vascular conductance (RVC was calculated as the ratio of RBF by MAP. In anesthetized rats (n = 6, OT infusion (0.03 µg • kg(-1, i.v. induced renal vasodilation. Consistent with this result, ex vivo experiments demonstrated that OT caused renal artery relaxation. Blockade of OT receptors (OXTR reduced these responses to OT, indicating a direct effect of this peptide on OXTR on this artery. Hypertonic saline (3 M NaCl, 1.8 ml • kg(-1 b.wt., i.v. was infused over 60 s. In sham rats (n = 6, hypertonic saline induced renal vasodilation. The OXTR antagonist (AT; atosiban, 40 µg • kg(-1 • h(-1, i.v.; n = 7 and renal denervation (RX reduced the renal vasodilation induced by hypernatremia. The combination of atosiban and renal denervation (RX+AT; n = 7 completely abolished the renal vasodilation induced by sodium overload. Intact rats excreted 51% of the injected sodium within 90 min. Natriuresis was slightly blunted by atosiban and renal denervation (42% and 39% of load, respectively, whereas atosiban with renal denervation reduced sodium excretion to 16% of the load. These results suggest that OT and renal nerves are involved in renal vasodilation and natriuresis induced by acute plasma hypernatremia.

  17. Quantitative evaluation of right ventricular overload in cor pulmonale using sup 201 Tl myocardial SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Hiroshi; Misawa, Toshihiro; Kutsumi, Yasunori [Fukui Medical School, Matsuoka (Japan); and others

    1991-01-01

    To determine quantitatively the discriminant and characteristics of cor pulmonale, {sup 201}Tl myocardial perfusion SPECT was performed in 16 patients with chronic obstructive pulmonary disease (COPD) and 7 with restrictive pulmonary disease (RPD). One section of the short-axis SPECT image in which the right ventricle was most clearly visualized was selected. Tl-score was defined as the ratio of the sum of counts in the region of interest (ROI) at the anterior, mid, and posterior regions of the right ventricular free wall to the sum of counts in ROI at the posterior, lateral, and anterior walls of the left ventricle, and the anterior and posterior regions of the interventricular septum. In the group of COPD patients, Tl-score was positively correlated with mean pulmonary arterial pressure (mPAP), total pulmonary vascular resistance (TPR), and arterial carbon dioxide tension (PaCO{sub 2}), while it was inversely correlated with arterial oxygen tension (PaO{sub 2}). However, there was no significant correlation between Tl-score and mPAP, TPR, PaCO{sub 2}, and PaO{sub 2} in the group of RPD patients. In assessing pulmonary hypertension as defined by mPAP over 20 mmHg, a Tl-score greater than 0.25 was useful with a sensitivity of 69% and a specificity of 90%. The occurrence of cor pulmonale is a major factor in determining the prognosis of COPD patients. It was concluded that {sup 201}Tl myocardial SPECT is useful for evaluating right ventricular overload quantitatively, as well as for assessing core pulmonale, especially in COPD patients, since the ratio of Tl counts in the right and left ventricles was significantly correlated with right cardiopulmonary hemodynamic parameters. (N.K.).

  18. Milrinone and levosimendan during porcine myocardial ischemia -- no effects on calcium overload and metabolism.

    Science.gov (United States)

    Axelsson, B; Johansson, G; Abrahamsson, P; Gupta, A; Tydén, H; Wouters, P; Haney, M

    2013-07-01

    Although inotropic stimulation is considered harmful in the presence of myocardial ischaemia, both calcium sensitisers and phosphodiesterase inhibitors may offer cardioprotection. We hypothesise that these cardioprotective effects are related to an acute alteration of myocardial metabolism. We studied in vivo effects of milrinone and levosimendan on calcium overload and ischaemic markers using left ventricular microdialysis in pigs with acute myocardial ischaemia. Anaesthetised juvenile pigs, average weight 36 kg, were randomised to one of three intravenous treatment groups: milrinone 50 μg/kg bolus plus infusion 0.5 μg/kg/min (n = 7), levosimendan 24 μg/kg plus infusion 0.2 μg/kg/min (n = 7), or placebo (n = 6) for 60 min prior to and during a 45 min acute regional coronary occlusion. Systemic and myocardial haemodynamics were assessed, and microdialysis was performed with catheters positioned in the left ventricular wall. (45) Ca(2+) was included in the microperfusate in order to assess local calcium uptake into myocardial cells. The microdialysate was analysed for glucose, lactate, pyruvate, glycerol, and for (45) Ca(2+) recovery. During ischaemia, there were no differences in microdialysate-measured parameters between control animals and milrinone- or levosimendan-treated groups. In the pre-ischaemic period, arterial blood pressure decreased in all groups while myocardial oxygen consumption remained stable. These findings reject the hypothesis of an immediate energy-conserving effect of milrinone and levosimendan during acute myocardial ischaemia. On the other hand, the data show that inotropic support with milrinone and levosimendan does not worsen the metabolic parameters that were measured in the ischaemic myocardium. © 2013 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  19. Quantitative evaluation of right ventricular overload in cor pulmonale using 201Tl myocardial SPECT

    International Nuclear Information System (INIS)

    Kato, Hiroshi; Misawa, Toshihiro; Kutsumi, Yasunori

    1991-01-01

    To determine quantitatively the discriminant and characteristics of cor pulmonale, 201 Tl myocardial perfusion SPECT was performed in 16 patients with chronic obstructive pulmonary disease (COPD) and 7 with restrictive pulmonary disease (RPD). One section of the short-axis SPECT image in which the right ventricle was most clearly visualized was selected. Tl-score was defined as the ratio of the sum of counts in the region of interest (ROI) at the anterior, mid, and posterior regions of the right ventricular free wall to the sum of counts in ROI at the posterior, lateral, and anterior walls of the left ventricle, and the anterior and posterior regions of the interventricular septum. In the group of COPD patients, Tl-score was positively correlated with mean pulmonary arterial pressure (mPAP), total pulmonary vascular resistance (TPR), and arterial carbon dioxide tension (PaCO 2 ), while it was inversely correlated with arterial oxygen tension (PaO 2 ). However, there was no significant correlation between Tl-score and mPAP, TPR, PaCO 2 , and PaO 2 in the group of RPD patients. In assessing pulmonary hypertension as defined by mPAP over 20 mmHg, a Tl-score greater than 0.25 was useful with a sensitivity of 69% and a specificity of 90%. The occurrence of cor pulmonale is a major factor in determining the prognosis of COPD patients. It was concluded that 201 Tl myocardial SPECT is useful for evaluating right ventricular overload quantitatively, as well as for assessing core pulmonale, especially in COPD patients, since the ratio of Tl counts in the right and left ventricles was significantly correlated with right cardiopulmonary hemodynamic parameters. (N.K.)

  20. Iron overload promotes erythroid apoptosis through regulating HIF-1a/ROS signaling pathway in patients with myelodysplastic syndrome.

    Science.gov (United States)

    Zheng, Qing-Qing; Zhao, You-Shan; Guo, Juan; Zhao, Si-da; Song, Lu-Xi; Fei, Cheng-Ming; Zhang, Zheng; Li, Xiao; Chang, Chun-Kang

    2017-07-01

    Erythroid apoptosis increases significantly in myelodysplastic syndrome (MDS) patients with iron overload, but the underlying mechanism is not fully clear. In this study, we aim to explore the effect of HIF-1a/ROS on erythroid apoptosis in MDS patients with iron overload. We found that iron overload injured cellular functions through up-regulating ROS levels in MDS/AML cells, including inhibited cell viability, increased cell apoptosis and blocked cell cycle at G0/G1 phase. Interestingly, overexpression of hypoxia inducible factor-1a (HIF-1a), which was under-expressed in iron overload models, reduced ROS levels and attenuated cell damage caused by iron overload in MDS/AML cells. And gene knockdown of HIF-1a got the similar results as iron overload in MDS/AML cells. Furthermore, iron overload caused high erythroid apoptosis was closely related with ROS in MDS patients. Importantly, the HIF-1a protein levels of erythrocytes elevated obviously after incubation with desferrioxamine (DFO) from MDS patients with iron overload, accompanied by ROS levels inhibited and erythroid apoptosis reduced. Taken together, our findings determine that the HIF-1a/ROS signaling pathway plays a key role in promoting erythroid apoptosis in MDS patients with iron overload. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Maximal frustration as an immunological principle.

    Science.gov (United States)

    de Abreu, F Vistulo; Mostardinha, P

    2009-03-06

    A fundamental problem in immunology is that of understanding how the immune system selects promptly which cells to kill without harming the body. This problem poses an apparent paradox. Strong reactivity against pathogens seems incompatible with perfect tolerance towards self. We propose a different view on cellular reactivity to overcome this paradox: effector functions should be seen as the outcome of cellular decisions which can be in conflict with other cells' decisions. We argue that if cellular systems are frustrated, then extensive cross-reactivity among the elements in the system can decrease the reactivity of the system as a whole and induce perfect tolerance. Using numerical and mathematical analyses, we discuss two simple models that perform optimal pathogenic detection with no autoimmunity if cells are maximally frustrated. This study strongly suggests that a principle of maximal frustration could be used to build artificial immune systems. It would be interesting to test this principle in the real adaptive immune system.

  2. Derivative pricing based on local utility maximization

    OpenAIRE

    Jan Kallsen

    2002-01-01

    This paper discusses a new approach to contingent claim valuation in general incomplete market models. We determine the neutral derivative price which occurs if investors maximize their local utility and if derivative demand and supply are balanced. We also introduce the sensitivity process of a contingent claim. This process quantifies the reliability of the neutral derivative price and it can be used to construct price bounds. Moreover, it allows to calibrate market models in order to be co...

  3. Control of Shareholders’ Wealth Maximization in Nigeria

    OpenAIRE

    A. O. Oladipupo; C. O. Okafor

    2014-01-01

    This research focuses on who controls shareholder’s wealth maximization and how does this affect firm’s performance in publicly quoted non-financial companies in Nigeria. The shareholder fund was the dependent while explanatory variables were firm size (proxied by log of turnover), retained earning (representing management control) and dividend payment (representing measure of shareholders control). The data used for this study were obtained from the Nigerian Stock Exchange [NSE] fact book an...

  4. Definable maximal discrete sets in forcing extensions

    DEFF Research Database (Denmark)

    Törnquist, Asger Dag; Schrittesser, David

    2018-01-01

    Let  be a Σ11 binary relation, and recall that a set A is -discrete if no two elements of A are related by . We show that in the Sacks and Miller forcing extensions of L there is a Δ12 maximal -discrete set. We use this to answer in the negative the main question posed in [5] by showing...

  5. Dynamic Convex Duality in Constrained Utility Maximization

    OpenAIRE

    Li, Yusong; Zheng, Harry

    2016-01-01

    In this paper, we study a constrained utility maximization problem following the convex duality approach. After formulating the primal and dual problems, we construct the necessary and sufficient conditions for both the primal and dual problems in terms of FBSDEs plus additional conditions. Such formulation then allows us to explicitly characterize the primal optimal control as a function of the adjoint process coming from the dual FBSDEs in a dynamic fashion and vice versa. Moreover, we also...

  6. Mitochondrial Ca2+ overload underlies Abeta oligomers neurotoxicity providing an unexpected mechanism of neuroprotection by NSAIDs.

    Science.gov (United States)

    Sanz-Blasco, Sara; Valero, Ruth A; Rodríguez-Crespo, Ignacio; Villalobos, Carlos; Núñez, Lucía

    2008-07-23

    Dysregulation of intracellular Ca(2+) homeostasis may underlie amyloid beta peptide (Abeta) toxicity in Alzheimer's Disease (AD) but the mechanism is unknown. In search for this mechanism we found that Abeta(1-42) oligomers, the assembly state correlating best with cognitive decline in AD, but not Abeta fibrils, induce a massive entry of Ca(2+) in neurons and promote mitochondrial Ca(2+) overload as shown by bioluminescence imaging of targeted aequorin in individual neurons. Abeta oligomers induce also mitochondrial permeability transition, cytochrome c release, apoptosis and cell death. Mitochondrial depolarization prevents mitochondrial Ca(2+) overload, cytochrome c release and cell death. In addition, we found that a series of non-steroidal anti-inflammatory drugs (NSAIDs) including salicylate, sulindac sulfide, indomethacin, ibuprofen and R-flurbiprofen depolarize mitochondria and inhibit mitochondrial Ca(2+) overload, cytochrome c release and cell death induced by Abeta oligomers. Our results indicate that i) mitochondrial Ca(2+) overload underlies the neurotoxicity induced by Abeta oligomers and ii) inhibition of mitochondrial Ca(2+) overload provides a novel mechanism of neuroprotection by NSAIDs against Abeta oligomers and AD.

  7. AMPKγ3 is dispensable for skeletal muscle hypertrophy induced by functional overload.

    Science.gov (United States)

    Riedl, Isabelle; Osler, Megan E; Björnholm, Marie; Egan, Brendan; Nader, Gustavo A; Chibalin, Alexander V; Zierath, Juleen R

    2016-03-15

    Mechanisms regulating skeletal muscle growth involve a balance between the activity of serine/threonine protein kinases, including the mammalian target of rapamycin (mTOR) and 5'-AMP-activated protein kinase (AMPK). The contribution of different AMPK subunits to the regulation of cell growth size remains inadequately characterized. Using AMPKγ3 mutant-overexpressing transgenic Tg-Prkag3(225Q) and AMPKγ3-knockout (Prkag3(-/-)) mice, we investigated the requirement for the AMPKγ3 isoform in functional overload-induced muscle hypertrophy. Although the genetic disruption of the γ3 isoform did not impair muscle growth, control sham-operated AMPKγ3-transgenic mice displayed heavier plantaris muscles in response to overload hypertrophy and underwent smaller mass gain and lower Igf1 expression compared with wild-type littermates. The mTOR signaling pathway was upregulated with functional overload but unchanged between genetically modified animals and wild-type littermates. Differences in AMPK-related signaling pathways between transgenic, knockout, and wild-type mice did not impact muscle hypertrophy. Glycogen content was increased following overload in wild-type mice. In conclusion, our functional, transcriptional, and signaling data provide evidence against the involvement of the AMPKγ3 isoform in the regulation of skeletal muscle hypertrophy. Thus, the AMPKγ3 isoform is dispensable for functional overload-induced muscle growth. Mechanical loading can override signaling pathways that act as negative effectors of mTOR signaling and consequently promote skeletal muscle hypertrophy. Copyright © 2016 the American Physiological Society.

  8. Heat shock transcription factor 1-deficiency attenuates overloading-associated hypertrophy of mouse soleus muscle.

    Science.gov (United States)

    Koya, Tomoyuki; Nishizawa, Sono; Ohno, Yoshitaka; Goto, Ayumi; Ikuta, Akihiro; Suzuki, Miho; Ohira, Tomotaka; Egawa, Tatsuro; Nakai, Akira; Sugiura, Takao; Ohira, Yoshinobu; Yoshioka, Toshitada; Beppu, Moroe; Goto, Katsumasa

    2013-01-01

    Hypertrophic stimuli, such as mechanical stress and overloading, induce stress response, which is mediated by heat shock transcription factor 1 (HSF1), and up-regulate heat shock proteins (HSPs) in mammalian skeletal muscles. Therefore, HSF1-associated stress response may play a key role in loading-associated skeletal muscle hypertrophy. The purpose of this study was to investigate the effects of HSF1-deficiency on skeletal muscle hypertrophy caused by overloading. Functional overloading on the left soleus was performed by cutting the distal tendons of gastrocnemius and plantaris muscles for 4 weeks. The right muscle served as the control. Soleus muscles from both hindlimbs were dissected 2 and 4 weeks after the operation. Hypertrophy of soleus muscle in HSF1-null mice was partially inhibited, compared with that in wild-type (C57BL/6J) mice. Absence of HSF1 partially attenuated the increase of muscle wet weight and fiber cross-sectional area of overloaded soleus muscle. Population of Pax7-positive muscle satellite cells in HSF1-null mice was significantly less than that in wild-type mice following 2 weeks of overloading (pmuscle hypertrophy might be attributed to the greater and prolonged enhancement of IL-6 expression. HSF1 and/or HSF1-mediated stress response may, in part, play a key role in loading-induced skeletal muscle hypertrophy.

  9. Mitochondrial Ca2+ overload underlies Abeta oligomers neurotoxicity providing an unexpected mechanism of neuroprotection by NSAIDs.

    Directory of Open Access Journals (Sweden)

    Sara Sanz-Blasco

    Full Text Available Dysregulation of intracellular Ca(2+ homeostasis may underlie amyloid beta peptide (Abeta toxicity in Alzheimer's Disease (AD but the mechanism is unknown. In search for this mechanism we found that Abeta(1-42 oligomers, the assembly state correlating best with cognitive decline in AD, but not Abeta fibrils, induce a massive entry of Ca(2+ in neurons and promote mitochondrial Ca(2+ overload as shown by bioluminescence imaging of targeted aequorin in individual neurons. Abeta oligomers induce also mitochondrial permeability transition, cytochrome c release, apoptosis and cell death. Mitochondrial depolarization prevents mitochondrial Ca(2+ overload, cytochrome c release and cell death. In addition, we found that a series of non-steroidal anti-inflammatory drugs (NSAIDs including salicylate, sulindac sulfide, indomethacin, ibuprofen and R-flurbiprofen depolarize mitochondria and inhibit mitochondrial Ca(2+ overload, cytochrome c release and cell death induced by Abeta oligomers. Our results indicate that i mitochondrial Ca(2+ overload underlies the neurotoxicity induced by Abeta oligomers and ii inhibition of mitochondrial Ca(2+ overload provides a novel mechanism of neuroprotection by NSAIDs against Abeta oligomers and AD.

  10. A study on fatigue crack growth behavior subjected to a single tensile overload

    International Nuclear Information System (INIS)

    Lee, S.Y.; Liaw, P.K.; Choo, H.; Rogge, R.B.

    2011-01-01

    Neutron diffraction and electric potential experiments were carried out to investigate the growth behavior of a fatigue crack subjected to a single tensile overload. The specific objectives were to (i) probe the crack tip deformation and fracture behaviors under applied loads; (ii) examine the overload-induced transient crack growth micromechanism; (iii) validate the effective stress intensity factor range based on the crack closure approach as the fatigue crack tip driving force; and (iv) establish a quantitative relationship between the crack tip driving force and crack growth behavior. Immediately after a single tensile overload was introduced and then unloaded, the crack tip became blunt and enlarged compressive residual stresses in both magnitude and zone size were observed around the crack tip. The results show that the combined contributions of the overload-induced enlarged compressive residual stresses and crack tip blunting with secondary cracks are responsible for the observed changes in the crack opening load and the resultant post-overload transient crack growth behavior.

  11. Resilience of electricity grids against transmission line overloads under wind power injection at different nodes.

    Science.gov (United States)

    Schiel, Christoph; Lind, Pedro G; Maass, Philipp

    2017-09-14

    A steadily increasing fraction of renewable energy sources for electricity production requires a better understanding of how stochastic power generation affects the stability of electricity grids. Here, we assess the resilience of an IEEE test grid against single transmission line overloads under wind power injection based on the dc power flow equations and a quasi-static grid response to wind fluctuations. Thereby we focus on the mutual influence of wind power generation at different nodes. We find that overload probabilities vary strongly between different pairs of nodes and become highly affected by spatial correlations of wind fluctuations. An unexpected behaviour is uncovered: for a large number of node pairs, increasing wind power injection at one node can increase the power threshold at the other node with respect to line overloads in the grid. We find that this seemingly paradoxical behaviour is related to the topological distance of the overloaded line from the shortest path connecting the wind nodes. In the considered test grid, it occurs for all node pairs, where the overloaded line belongs to the shortest path.

  12. Reducing unidentified MOV failures: An innovative approach to thermal overload monitoring

    International Nuclear Information System (INIS)

    Hill, K.; Watson, M.E.; Ali, H.S.; Schlesinger, R.

    1991-01-01

    Historically the failure of motor-operated valves to actuate on demand has caused plant transients, reduced safety system reliability, and lost plant availability. The typical control and indication circuit design uses thermal overload contacts in the control circuit only. This has been recognized as a significant unidentified valve failure mode that may prevent the valve from performing its safety function when required. Different approaches have been evaluated to alert operations personnel to this thermal overload condition, but no cost-effective solution has provided indication of the thermal overload while maintaining valve position indication. Iowa Electric Light and Power Company's Duane Arnold Energy Center (DAEC) is utilizing a nuclear-qualified thermal overload monitor in valve control and indication circuits. This innovative approach has proven economical as no new cabling or indicating devices are required. Indication is provided using existing valve position indicating lights. The monitor is engineered to provide indication of a thermal overload trip as well as continuous indication of valve position, consistent with Regulatory Guide 1.97 and guidance provided by Generic Letter 89-10

  13. Update on the use of deferasirox in the management of iron overload

    Directory of Open Access Journals (Sweden)

    Ali Taher

    2009-10-01

    Full Text Available Ali Taher,1 Maria Domenica Cappellini21American University of Beirut, Beirut, Lebanon; 2Universitá di Milano, Policlinico Foundation IRCCS, Milan, ItalyAbstract: Regular blood transfusions as supportive care for patients with chronic anemia inevitably lead to iron overload as humans cannot actively remove excess iron. The cumulative effects of iron overload cause significant morbidity and mortality if not effectively treated with chelation therapy. Based on a comprehensive clinical development program, the once-daily, oral iron chelator deferasirox (Exjade® is approved for the treatment of transfusional iron overload in adult and pediatric patients with various transfusion-dependent anemias, including β-thalassemia and the myelodysplastic syndromes. Deferasirox dose should be titrated for each individual patient based on transfusional iron intake, current iron burden and whether the goal is to decrease or maintain body iron levels. Doses of >30 mg/kg/day have been shown to be effective with a safety profile consistent with that observed at doses <30 mg/kg/day. Recent data have highlighted the ability of deferasirox to decrease cardiac iron levels and to prevent the accumulation of iron in the heart. The long-term efficacy and safety of deferasirox for up to 5 years of treatment have now been established. The availability of this effective and generally well tolerated oral therapy represents a significant advance in the management of transfusional iron overload. Keywords: deferasirox, Exjade, oral, iron chelation, iron overload, cardiac iron 

  14. Learners' perceived information overload in online learning via computer-mediated communication

    Directory of Open Access Journals (Sweden)

    Karen L. Murphy

    2011-12-01

    Full Text Available Many studies report information overload as one of the main problems that students encounter in online learning via computer-mediated communication. This study aimed to explore the sources of online students' information overload and offer suggestions for increasing students' cognitive resources for learning. Participants were 12 graduate students from two online courses in the United States. Their learning experiences in both online discussions and on the course website were explored through semi-structured interviews. They also completed a background questionnaire that assessed three constructs that limit learner readiness and are likely to lead to online students' perceived information overload: inadequate prior knowledge, inadequate English proficiency, and lack of technical skills for participating in computer-mediated communications. The findings suggest that varied learner characteristics led some students to be more susceptible than others to information overload. Emerging data-driven risk factors were: lack of efficiency in reading from computer screens, visual and auditory learning preferences, and time constraints. Difficulties associated with students' perceptions of information overload are addressed and implications for course design are offered.

  15. Iron overload detection in rats by means of a susceptometer operating at room temperature

    International Nuclear Information System (INIS)

    Marinelli, M; Gianesin, B; Avignolo, C; Parodi, S; Minganti, V

    2008-01-01

    Biosusceptometry is a non-invasive procedure for determination of iron overload in a human body; it is essentially an assessment of the diamagnetic (water) and paramagnetic (iron) properties of tissues. We measured in vivo iron overload in the liver region of 12 rats by a room temperature susceptometer. The rats had been injected with sub-toxic doses of iron dextran. A quantitative relationship has been observed between the measurements and the number of treatments. The assessment of iron overload requires evaluating the magnetic signal corresponding to the same rat ideally without the overload. This background value was extrapolated on the basis of the signal measured in control rats versus body weight (R 2 = 0.73). The mean iron overload values for the treated rats, obtained after each iron injection, were significantly different from the means of the corresponding control rats (p 2 = 0.89). The magnetic moment of iron atoms in liver tissues was measured to be 3.6 Bohr magneton. Evaluation of the background signal is the limit to the measure; the error corresponds to about 30 mg (1 SD) of iron while the instrument sensitivity is more than a factor of 10 better.

  16. SIRT1 may play a crucial role in overload-induced hypertrophy of skeletal muscle.

    Science.gov (United States)

    Koltai, Erika; Bori, Zoltán; Chabert, Clovis; Dubouchaud, Hervé; Naito, Hisashi; Machida, Shuichi; Davies, Kelvin Ja; Murlasits, Zsolt; Fry, Andrew C; Boldogh, Istvan; Radak, Zsolt

    2017-06-01

    Silent mating type information regulation 2 homologue 1 (SIRT1) activity and content increased significantly in overload-induced hypertrophy. SIRT1-mediated signalling through Akt, the endothelial nitric oxide synthase mediated pathway, regulates anabolic process in the hypertrophy of skeletal muscle. The regulation of catabolic signalling via forkhead box O 1 and protein ubiquitination is SIRT1 dependent. Overload-induced changes in microRNA levels regulate SIRT1 and insulin-like growth factor 1 signalling. Significant skeletal muscle mass guarantees functional wellbeing and is important for high level performance in many sports. Although the molecular mechanism for skeletal muscle hypertrophy has been well studied, it still is not completely understood. In the present study, we used a functional overload model to induce plantaris muscle hypertrophy by surgically removing the soleus and gastrocnemius muscles in rats. Two weeks of muscle ablation resulted in a 40% increase in muscle mass, which was associated with a significant increase in silent mating type information regulation 2 homologue 1 (SIRT1) content and activity (P overload-induced hypertrophy. These findings, along with the well-known regulatory roles that SIRT1 plays in modulating both anabolic and catabolic pathways, allow us to propose the hypothesis that SIRT1 may actually play a crucial causal role in overload-induced hypertrophy of skeletal muscle. This hypothesis will now require rigorous direct and functional testing. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

  17. Radionuclide stroke count ratios for assessment of right and left ventricular volume overload in children

    International Nuclear Information System (INIS)

    Parrish, M.D.; Graham, T.P. Jr.; Born, M.L.; Jones, J.P.; Boucek, R.J. Jr.; Artman, M.; Partain, C.L.

    1983-01-01

    The ratio of left ventricular to right ventricular stroke counts measured by radionuclide angiography has been used in adults to estimate the severity of left-sided valvular regurgitation. The validation of this technique in children for assessment of right and left ventricular volume overload is reported herein. Radionuclide stroke count ratios in 60 children aged 0.5 to 19 years (mean 11) were determined. Based on their diagnoses, the patients were divided into 3 groups: (1) normal--40 patients with no shunts or valvular regurgitation, (2) left ventricular volume overload--13 patients with mitral or aortic regurgitation, or both, and (3) right ventricular volume overload--7 patients, 2 with severe tricuspid regurgitation, 3 with atrial septal defects, and 2 with total anomalous pulmonary venous drainage. The radionuclide stroke count ratio clearly differentiated these groups (p less than 0.05): normal patients had a stroke count ratio of 1.04 +/- 0.17 (mean +/- 1 standard deviation), the left ventricular volume overload group had a stroke count ratio of 2.43 +/- 0.86, and the right ventricular volume overload group had a stroke count ratio of 0.44 +/- 0.17. In 22 of our 60 patients, radionuclide stroke count ratios were compared with cineangiographic stroke volume ratios, resulting in a correlation coefficient of 0.88. It is concluded that radionuclide ventriculography is an excellent tool for qualitative and quantitative assessment of valvular regurgitation in children

  18. Impact of iron overload and potential benefit from iron chelation in low-risk myelodysplastic syndrome.

    Science.gov (United States)

    Shenoy, Niraj; Vallumsetla, Nishanth; Rachmilewitz, Eliezer; Verma, Amit; Ginzburg, Yelena

    2014-08-07

    Myelodysplastic syndromes (MDSs) are a group of heterogeneous clonal bone marrow disorders characterized by ineffective hematopoiesis, peripheral blood cytopenias, and potential for malignant transformation. Lower/intermediate-risk MDSs are associated with longer survival and high red blood cell (RBC) transfusion requirements resulting in secondary iron overload. Recent data suggest that markers of iron overload portend a relatively poor prognosis, and retrospective analysis demonstrates that iron chelation therapy is associated with prolonged survival in transfusion-dependent MDS patients. New data provide concrete evidence of iron's adverse effects on erythroid precursors in vitro and in vivo. Renewed interest in the iron field was heralded by the discovery of hepcidin, the main serum peptide hormone negative regulator of body iron. Evidence from β-thalassemia suggests that regulation of hepcidin by erythropoiesis dominates regulation by iron. Because iron overload develops in some MDS patients who do not require RBC transfusions, the suppressive effect of ineffective erythropoiesis on hepcidin may also play a role in iron overload. We anticipate that additional novel tools for measuring iron overload and a molecular-mechanism-driven description of MDS subtypes will provide a deeper understanding of how iron metabolism and erythropoiesis intersect in MDSs and improve clinical management of this patient population. © 2014 by The American Society of Hematology.

  19. A composite mouse model of aplastic anemia complicated with iron overload.

    Science.gov (United States)

    Wu, Dijiong; Wen, Xiaowen; Liu, Wenbin; Xu, Linlong; Ye, Baodong; Zhou, Yuhong

    2018-02-01

    Iron overload is commonly encountered during the course of aplastic anemia (AA), but no composite animal model has been developed yet, which hinders drug research. In the present study, the optimal dosage and duration of intraperitoneal iron dextran injection for the development of an iron overload model in mice were explored. A composite model of AA was successfully established on the principle of immune-mediated bone marrow failure. Liver volume, peripheral hemogram, bone marrow pathology, serum iron, serum ferritin, pathological iron deposition in multiple organs (liver, bone marrow, spleen), liver hepcidin, and bone morphogenetic protein 6 (BMP6), SMAD family member 4 (SMAD4) and transferrin receptor 2 (TfR2) mRNA expression levels were compared among the normal control, AA, iron overload and composite model groups to validate the composite model, and explore the pathogenesis and features of iron overload in this model. The results indicated marked increases in iron deposits, with significantly increased liver/body weight ratios as well as serum iron and ferritin in the iron overload and composite model groups as compared with the normal control and AA groups (Poverload and AA was successfully established, and AA was indicated to possibly have a critical role in abnormal iron metabolism, which promoted the development of iron deposits.

  20. Peculiarities on voltage - current characteristics of HTS tapes at overloading conditions cooled by liquid nitrogen

    International Nuclear Information System (INIS)

    Vysotsky, V S; Fetisov, S S; Sytnikov, V E

    2008-01-01

    Electro - technical devices are considered as the most prospective use for high temperature superconductors. For such devices the overload currents due to faults in grids are the operational reality. In these cases the fault currents may forcibly go to superconductors being sometimes dozens times more than the critical currents of HTS. Overloads are the working modes for fault current limiters also. To understand the behavior of HTS devices at overloads it is important to study voltage-current characteristics (VCC) of basic HTS tapes in real cooling conditions. The knowledge of VCC permits to model and to simulate properly HTS devices behavior at overloads. We performed the study of VCC of several HTS tapes at currents several times more than their critical ones. Both, 1-G and 2-G tapes were tested. There were found peculiarities or 'spikes' on VCC at rising currents that vanished at decaying currents. It was shown that such peculiarities are determined by the change of cooling conditions from the convective heat exchange to the nucleate boiling. Nucleate boiling activation and development times were determined. Their dependencies on heat release were measured. The data obtained can be used in simulation of heating of real superconducting devices at overload conditions

  1. Nursing management of sensory overload in psychiatry – Theoretical densification and modification of the framework model

    Science.gov (United States)

    Scheydt, Stefan; Needham, Ian; Behrens, Johann

    2017-01-01

    Background: Within the scope of the research project on the subjects of sensory overload and stimulus regulation, a theoretical framework model of the nursing care of patients with sensory overload in psychiatry was developed. In a second step, this theoretical model should now be theoretically compressed and, if necessary, modified. Aim: Empirical verification as well as modification, enhancement and theoretical densification of the framework model of nursing care of patients with sensory overload in psychiatry. Method: Analysis of 8 expert interviews by summarizing and structuring content analysis methods based on Meuser and Nagel (2009) as well as Mayring (2010). Results: The developed framework model (Scheydt et al., 2016b) could be empirically verified, theoretically densificated and extended by one category (perception modulation). Thus, four categories of nursing care of patients with sensory overload can be described in inpatient psychiatry: removal from stimuli, modulation of environmental factors, perceptual modulation as well as help somebody to help him- or herself / coping support. Conclusions: Based on the methodological approach, a relatively well-saturated, credible conceptualization of a theoretical model for the description of the nursing care of patients with sensory overload in stationary psychiatry could be worked out. In further steps, these measures have to be further developed, implemented and evaluated regarding to their efficacy.

  2. Single maximal versus combination punch kinematics.

    Science.gov (United States)

    Piorkowski, Barry A; Lees, Adrian; Barton, Gabor J

    2011-03-01

    The aim of this study was to determine the influence of punch type (Jab, Cross, Lead Hook and Reverse Hook) and punch modality (Single maximal, 'In-synch' and 'Out of synch' combination) on punch speed and delivery time. Ten competition-standard volunteers performed punches with markers placed on their anatomical landmarks for 3D motion capture with an eight-camera optoelectronic system. Speed and duration between key moments were computed. There were significant differences in contact speed between punch types (F(2,18,84.87) = 105.76, p = 0.001) with Lead and Reverse Hooks developing greater speed than Jab and Cross. There were significant differences in contact speed between punch modalities (F(2,64,102.87) = 23.52, p = 0.001) with the Single maximal (M+/- SD: 9.26 +/- 2.09 m/s) higher than 'Out of synch' (7.49 +/- 2.32 m/s), 'In-synch' left (8.01 +/- 2.35 m/s) or right lead (7.97 +/- 2.53 m/s). Delivery times were significantly lower for Jab and Cross than Hook. Times were significantly lower 'In-synch' than a Single maximal or 'Out of synch' combination mode. It is concluded that a defender may have more evasion-time than previously reported. This research could be of use to performers and coaches when considering training preparations.

  3. Formation Control for the MAXIM Mission

    Science.gov (United States)

    Luquette, Richard J.; Leitner, Jesse; Gendreau, Keith; Sanner, Robert M.

    2004-01-01

    Over the next twenty years, a wave of change is occurring in the space-based scientific remote sensing community. While the fundamental limits in the spatial and angular resolution achievable in spacecraft have been reached, based on today s technology, an expansive new technology base has appeared over the past decade in the area of Distributed Space Systems (DSS). A key subset of the DSS technology area is that which covers precision formation flying of space vehicles. Through precision formation flying, the baselines, previously defined by the largest monolithic structure which could fit in the largest launch vehicle fairing, are now virtually unlimited. Several missions including the Micro-Arcsecond X-ray Imaging Mission (MAXIM), and the Stellar Imager will drive the formation flying challenges to achieve unprecedented baselines for high resolution, extended-scene, interferometry in the ultraviolet and X-ray regimes. This paper focuses on establishing the feasibility for the formation control of the MAXIM mission. MAXIM formation flying requirements are on the order of microns, while Stellar Imager mission requirements are on the order of nanometers. This paper specifically addresses: (1) high-level science requirements for these missions and how they evolve into engineering requirements; and (2) the development of linearized equations of relative motion for a formation operating in an n-body gravitational field. Linearized equations of motion provide the ground work for linear formation control designs.

  4. Gradient Dynamics and Entropy Production Maximization

    Science.gov (United States)

    Janečka, Adam; Pavelka, Michal

    2018-01-01

    We compare two methods for modeling dissipative processes, namely gradient dynamics and entropy production maximization. Both methods require similar physical inputs-how energy (or entropy) is stored and how it is dissipated. Gradient dynamics describes irreversible evolution by means of dissipation potential and entropy, it automatically satisfies Onsager reciprocal relations as well as their nonlinear generalization (Maxwell-Onsager relations), and it has statistical interpretation. Entropy production maximization is based on knowledge of free energy (or another thermodynamic potential) and entropy production. It also leads to the linear Onsager reciprocal relations and it has proven successful in thermodynamics of complex materials. Both methods are thermodynamically sound as they ensure approach to equilibrium, and we compare them and discuss their advantages and shortcomings. In particular, conditions under which the two approaches coincide and are capable of providing the same constitutive relations are identified. Besides, a commonly used but not often mentioned step in the entropy production maximization is pinpointed and the condition of incompressibility is incorporated into gradient dynamics.

  5. Uncoupling and oxidative stress in liver mitochondria isolated from rats with acute iron overload

    Energy Technology Data Exchange (ETDEWEB)

    Pardo Andreu, G.L. [Centro de Quimica Farmaceutica, Departamento de Investigaciones Biomedicas, Ciudad de La Habana (Cuba); Inada, N.M.; Vercesi, A.E. [Universidade Estadual de Campinas, Departamento de Patologia Clinica, Faculdade de Ciencias Medicas, Campinas, SP (Brazil); Curti, C. [Universidade de Sao Paulo, Departamento de Fisica e Quimica, Faculdade de Ciencias Farmaceuticas de Ribeirao Preto, SP (Brazil)

    2009-01-15

    One hypothesis for the etiology of cell damage arising from iron overload is that its excess selectively affects mitochondria. Here we tested the effects of acute iron overload on liver mitochondria isolated from rats subjected to a single dose of i.p. 500 mg/kg iron-dextran. The treatment increased the levels of iron in mitochondria (from 21{+-}4 to 130{+-}7 nmol/mg protein) and caused both lipid peroxidation and glutathione oxidation. The mitochondria of iron-treated rats showed lower respiratory control ratio in association with higher resting respiration. The mitochondrial uncoupling elicited by iron-treatment did not affect the phosphorylation efficiency or the ATP levels, suggesting that uncoupling is a mitochondrial protective mechanism against acute iron overload. Therefore, the reactive oxygen species (ROS)/H{sup +} leak couple, functioning as a mitochondrial redox homeostatic mechanism could play a protective role in the acutely iron-loaded mitochondria. (orig.)

  6. A new approach to quantify the additional effect of primary overloads on ratcheting

    International Nuclear Information System (INIS)

    Waeckel, N.; Faure, O.; Sperandio, M.; Cousin, M.; Taleb, L.

    1991-01-01

    Taking into account the temporary nature of overloads reduces the conservatism of the current RCC-MR rules for prevention of ratcheting. An empirical K factor determined by the BITUBE tests carried out at INSA LYON, permits to quantify the influence of short-term mechanical overloads by comparison with the case without overload. The prediction of ratcheting risks by the RCC-MR efficiency diagram using a fictitious increased primary load by a K-factor is more fitted to the design of structures submitted to seisms. From then on, taking advantage of the workability of the experimental device BITUBE a new tests program has begun to confirm the results expressed above. (author)

  7. The impact of faulty response of overload protection systems on the reliability of electricity supply

    International Nuclear Information System (INIS)

    Schweigert, J.; Schnuerer, G.

    1988-01-01

    Protection equipment of the engineered safety system which is to prevent the triggering of actions via signals from the reactor protection system is to be made so reliable that it has no impact on the non-availability of the supplied systems. Design and functional mode of the various overload protection equipment and the relevant switching device and combinations are explained together with the requirements such as choice, design, and adjustment of the protection equipment, followed by a survey of possible causes of faulty response of overload protection device and of the means and measures available for improvement. The now presented version of September 1987 of the 'overload protection report deals basically with all main topics of the Juli 1985 version, but has been updated and extended by material taking into account practice-oriented data on the new developments in convoy power plant design. (orig./HP) [de

  8. Effect of short-term overloads on crack propagation under creep

    International Nuclear Information System (INIS)

    Sushok, V.V.; Sobolev, N.D.; Zolotukhin, S.Yu.

    1986-01-01

    Kinetics of crack propagation after overload has been studied using plane samples of Kh18N10T steel. Tests of samples with a notch have been carried out in the air at 293 K. Observation of the crack growth has been carried out by the microscope and the method of electric potential difference. It is established that during overload besides crack tip blunting, decrease of creep rate of the material stregthened near it, that leads to crack retardation, decrease of plasticity and formation of microcracks in front of the tip of the main-line crack occurs. It is marked that, estimating serviceability of a member, it is necessary to take into account the decrease of crack propagation rate after short term overloads

  9. Analysis of short and long crack behavior and single overload effect by crack opening stress

    International Nuclear Information System (INIS)

    Song, Sam Hong; Lee, Kyeong Ro

    1999-01-01

    The study analyzed the behaviors of short and long crack as well as the effect of single tensile overload on the crack behaviors by using fatigue crack opening behavior. Crack opening stress is measured by an elastic compliance method which may precisely and continuously provide many data using strain gages during experiment. The unusual growth behaviors of short crack and crack after the single tensile overload applied, was explained by the variations of crack opening stress. In addition, fatigue crack growth rate was expressed as a linear form for short crack as for long crack by using effective stress intensity factor range as fracture mechanical parameter, which is based on crack closure concept. And investigation is performed with respect to the relation between plastic zone size formed at the crack tip and crack retardation, crack length and the number of cycles promoted or retarded, and the overload effect on the fatigue life

  10. Information Diffusion in Facebook-Like Social Networks Under Information Overload

    Science.gov (United States)

    Li, Pei; Xing, Kai; Wang, Dapeng; Zhang, Xin; Wang, Hui

    2013-07-01

    Research on social networks has received remarkable attention, since many people use social networks to broadcast information and stay connected with their friends. However, due to the information overload in social networks, it becomes increasingly difficult for users to find useful information. This paper takes Facebook-like social networks into account, and models the process of information diffusion under information overload. The term view scope is introduced to model the user information-processing capability under information overload, and the average number of times a message appears in view scopes after it is generated is proposed to characterize the information diffusion efficiency. Through theoretical analysis, we find that factors such as network structure and view scope number have no impact on the information diffusion efficiency, which is a surprising result. To verify the results, we conduct simulations and provide the simulation results, which are consistent with the theoretical analysis results perfectly.

  11. Overload-induced skeletal muscle hypertrophy is not impaired in STZ-diabetic rats

    Science.gov (United States)

    Fortes, Marco Aurélio S; Pinheiro, Carlos Hermano J; Guimarães-Ferreira, Lucas; Vitzel, Kaio F; Vasconcelos, Diogo A A; Curi, Rui

    2015-01-01

    The aim of this study was to evaluate the effect of overload-induced hypertrophy on extensor digitorum longus (EDL) and soleus muscles of streptozotocin-induced diabetic rats. The overload-induced hypertrophy and absolute tetanic and twitch forces increases in EDL and soleus muscles were not different between diabetic and control rats. Phospho-Akt and rpS6 contents were increased in EDL muscle after 7 days of overload and returned to the pre-overload values after 30 days. In the soleus muscle, the contents of total and phospho-Akt and total rpS6 were increased in both groups after 7 days. The contents of total Akt in controls and total rpS6 and phospho-Akt in the diabetic rats remained increased after 30 days. mRNA expression after 7 days of overload in the EDL muscle of control and diabetic animals showed an increase in MGF and follistatin and a decrease in myostatin and Axin2. The expression of FAK was increased and of MuRF-1 and atrogin-1 decreased only in the control group, whereas Ankrd2 expression was enhanced only in diabetic rats. In the soleus muscle caused similar changes in both groups: increase in FAK and MGF and decrease in Wnt7a, MuRF-1, atrogin-1, and myostatin. Differences between groups were observed only in the increased expression of follistatin in diabetic animals and decreased Ankrd2 expression in the control group. So, insulin deficiency does not impair the overload-induced hypertrophic response in soleus and EDL muscles. However, different mechanisms seem to be involved in the comparable hypertrophic responses of skeletal muscle in control and diabetic animals. PMID:26197932

  12. Correlation between Ribosome Biogenesis and the Magnitude of Hypertrophy in Overloaded Skeletal Muscle.

    Science.gov (United States)

    Nakada, Satoshi; Ogasawara, Riki; Kawada, Shigeo; Maekawa, Takahiro; Ishii, Naokata

    2016-01-01

    External loads applied to skeletal muscle cause increases in the protein translation rate, which leads to muscle hypertrophy. Although some studies have demonstrated that increases in the capacity and efficiency of translation are involved in this process, it remains unclear how these two factors are related to the magnitude of muscle hypertrophy. The present study aimed to clarify the roles played by the capacity and efficiency of translation in muscle hypertrophy. We used an improved synergist ablation in which the magnitude of compensatory hypertrophy could be controlled by partial removal of synergist muscles. Male rats were assigned to four groups in which the plantaris muscle was unilaterally subjected to weak (WK), moderate (MO), middle (MI), and strong (ST) overloading by four types of synergist ablation. Fourteen days after surgery, the weight of the plantaris muscle per body weight increased by 8%, 22%, 32% and 45%, in the WK, MO, MI and ST groups, respectively. Five days after surgery, 18+28S rRNA content (an indicator of translational capacity) increased with increasing overload, with increases of 1.8-fold (MO), 2.2-fold (MI), and 2.5-fold (ST), respectively, relative to non-overloaded muscle (NL) in the WK group. rRNA content showed a strong correlation with relative muscle weight measured 14 days after surgery (r = 0.98). The phosphorylated form of p70S6K (a positive regulator of translational efficiency) showed a marked increase in the MO group, but no further increase was observed with further increase in overload (increases of 22.6-fold (MO), 17.4-fold (MI), and 18.2-fold (ST), respectively, relative to NL in the WK group). These results indicate that increases in ribosome biogenesis at the early phase of overloading are strongly dependent on the amount of overloading, and may play an important role in increasing the translational capacity for further gain of muscular size.

  13. Hepatic iron overload is associated with hepatocyte apoptosis during Clonorchis sinensis infection.

    Science.gov (United States)

    Han, Su; Tang, Qiaoran; Chen, Rui; Li, Yihong; Shu, Jing; Zhang, Xiaoli

    2017-08-01

    Hepatic iron overload has been implicated in many liver diseases; however, whether it is involved in clonorchiasis remains unknown. The purpose of this study is to investigate whether Clonorchis sinensis (C. sinensis) infection causes hepatic iron overload, analyze the relationship between the iron overload and associated cell apoptosis, so as to determine the role of excess iron plays in C. sinensis-induced liver injury. The Perls' Prussian staining and atomic absorption spectrometry methods were used to investigate the iron overload in hepatic sections of wistar rats and patients infected with C. sinensis. The hepatic apoptosis was detected by transferase uridyl nick end labeling (TUNEL) methods. Spearman analysis was used for determining the correlation of the histological hepatic iron index and the apoptotic index. Blue iron particles were deposited mainly in the hepatocytes, Kupffer cells and endothelial cells, around the liver portal and central vein area of both patients and rats. The total iron score was found to be higher in the infected groups than the respective control from 8 weeks. The hepatic iron concentration was also significantly higher in treatment groups than in control rats from 8 weeks. The hepatocyte apoptosis was found to be significantly higher in the portal area of the liver tissue and around the central vein. However, spearman's rank correlation coefficient revealed that there was a mildly negative correlation between the iron index and hepatocyte apoptosis. This present study confirmed that hepatic iron overload was found during C. sinensis infection. This suggests that iron overload may be associated with hepatocyte apoptosis and involved in liver injury during C. sinensis infection. Further studies are needed to investigate the molecular mechanism involved here.

  14. Assessment of Iron Overload in Homozygous and Heterozygous Beta Thalassemic Children below 5 Years of Age

    Directory of Open Access Journals (Sweden)

    Dhiraj J. Trivedi

    2014-07-01

    Full Text Available Background: Thalassemia is a genetic disease having 3-7% carrier rate in Indians. It is transfusion dependent anemia having high risk of iron overloading. A clinical symptom of iron overload becomes detectable in second decade causing progressive liver, heart and endocrine glands damage. There is a need to assess iron overload in thalassemics below 5 years of age to protect them from complications at later age of life. Aims and objectives: Present study was undertaken to estimate serum iron status and evaluate serum transferrin saturation in both homozygous & heterozygous form of thalassemia as an index of iron overload among children of one to five years of age. Materials and Methods: Clinically diagnosed thirty cases of β thalassemia major & thirty cases of β thalassemia minor having severe anemia, hepatospleenomegaly and between 1 year to 5 years of age were included in study group and same age matched healthy controls were included in the study. RBC indices and HbA, HbA2 and HbF were estimated along with serum iron & serum Total Iron Binding Capacity (TIBC and serum transferrin levels. Results: Significant difference was observed in hemoglobin levels between control and both beta thalassemia groups. Mean Corpuscular Volume (MCV and Mean Corpuscular Hemoglobin (MCH values were reduced. Hemoglobin electrophoresis showed the elevated levels of HbF and HbA2 in both beta thalassemia groups. Among serum iron parameters, serum iron, TIBC and transferrin saturation were elevated whereas serum transferrin levels were low in thalassemia major in children below 5 years of age. Conclusion: Although clinical symptoms of iron overload have been absent in thalassemic children below five years of age, biochemical iron overloading has started at much lower age which is of great concern.

  15. Correlation between Ribosome Biogenesis and the Magnitude of Hypertrophy in Overloaded Skeletal Muscle.

    Directory of Open Access Journals (Sweden)

    Satoshi Nakada

    Full Text Available External loads applied to skeletal muscle cause increases in the protein translation rate, which leads to muscle hypertrophy. Although some studies have demonstrated that increases in the capacity and efficiency of translation are involved in this process, it remains unclear how these two factors are related to the magnitude of muscle hypertrophy. The present study aimed to clarify the roles played by the capacity and efficiency of translation in muscle hypertrophy. We used an improved synergist ablation in which the magnitude of compensatory hypertrophy could be controlled by partial removal of synergist muscles. Male rats were assigned to four groups in which the plantaris muscle was unilaterally subjected to weak (WK, moderate (MO, middle (MI, and strong (ST overloading by four types of synergist ablation. Fourteen days after surgery, the weight of the plantaris muscle per body weight increased by 8%, 22%, 32% and 45%, in the WK, MO, MI and ST groups, respectively. Five days after surgery, 18+28S rRNA content (an indicator of translational capacity increased with increasing overload, with increases of 1.8-fold (MO, 2.2-fold (MI, and 2.5-fold (ST, respectively, relative to non-overloaded muscle (NL in the WK group. rRNA content showed a strong correlation with relative muscle weight measured 14 days after surgery (r = 0.98. The phosphorylated form of p70S6K (a positive regulator of translational efficiency showed a marked increase in the MO group, but no further increase was observed with further increase in overload (increases of 22.6-fold (MO, 17.4-fold (MI, and 18.2-fold (ST, respectively, relative to NL in the WK group. These results indicate that increases in ribosome biogenesis at the early phase of overloading are strongly dependent on the amount of overloading, and may play an important role in increasing the translational capacity for further gain of muscular size.

  16. Evaluation Of The Overload Of Care In Families Of Psychiatric Patients In Psychosocial Care Center

    Directory of Open Access Journals (Sweden)

    Mayron Morais Almeida

    2017-07-01

    Full Text Available Introduction: The burden of care in family refers to the weight caused by the primary caregiver role to psychiatric patients and the difficulties encountered in performing this function in daily life. Objectives: Assessing the objective and subjective overload of family members who live with the reality of psychiatric disorder in a child day-care psychosocial care center. Methods: Cross-sectional study, descriptive-exploratory, of quantitative approach, with non-probabilistic samples of accidental type with 80 families of psychiatric patients held in a Psychosocial Care Center. For overload evaluation, the subscales "B" and "D" of the Family Overload Rating Scale (FBIS-BR were used. Results: The study was conducted with 80 families of psychiatric patients. The average age of female caregivers was 39,6 years old, and 40,7 years old for male caregivers, with female predominance (87,5% compared to men (12,5%, with low education for both genres. Family caregivers presented high objective burden due to excessive demand attention (p<0,001, heteroaggressiveness (p<0,001 and perplexing behavior of psychiatric patients regarding the supervision of problematic behaviors (p<0,001. The items on the impact on the family's daily routine have not helped to generate objective overload for the family members. On subjective overload, it was clear to observe familiar members with high degree of disturbance in all the dimensions assessed (p < 0,001. Conclusion: The high degree of care overload observed in family members indicates the need to develop contacts with the family of the psychiatric patient to answer questions, offer support and assistance to the family caregiver. Keywords: Caregivers. Patients. Mental Health Services.

  17. Controlling Price-Responsive Heat Pumps for Overload Elimination in Distribution Systems

    DEFF Research Database (Denmark)

    Csetvei, Zsuzsa; Østergaard, Jacob; Nyeng, Preben

    2011-01-01

    This paper investigates the possibility of applying electric heat pumps with the control-by-price-concept in order to avoid overload in a local distribution system. The proposed control algorithm is based upon a centrally dispatched real-time market price, reflecting the state of a larger power...... system, and is extended with a local price control for overload elimination on the corresponding feeder. The paper presents the mathematical models of a two-node system with price-responsive heat pumps, the chosen methodology of the central price calculation, and the proposed local feedback control...

  18. Geiger-mueller radiation detector with means for detecting and indicating the existence of radiation overload

    International Nuclear Information System (INIS)

    Kovacs, T.; Mills, A.P.; Pfeiffer, L.N.

    1981-01-01

    When subjected to radiation overload existing geiger-mueller counters may give an erroneously low reading, resulting in possible hazard to personnel. The instant invention discloses simple and inexpensive apparatus to remedy this dangerous shortcoming. Depending on the geometry of the detector tube, two possible failure modes have been identified, and circuitry is disclosed to detect the existence of these respective failure modes. The disclosed apparatus indicates the absence of an overload condition, in addition to signaling, by both visible and audible means, the existence of excessive radiation that might result in erroneously low reading of the geiger-mueller counter

  19. A quantitative approach to modeling the information processing of NPP operators under input information overload

    International Nuclear Information System (INIS)

    Kim, Jong Hyun; Seong, Poong Hyun

    2002-01-01

    This paper proposes a quantitative approach to modeling the information processing of NPP operators. The aim of this work is to derive the amount of the information processed during a certain control task under input information overload. We primarily develop the information processing model having multiple stages, which contains information flow. Then the uncertainty of the information is quantified using the Conant's model, a kind of information theory. We also investigate the applicability of this approach to quantifying the information reduction of operators under the input information overload

  20. Occlusal overload investigations by noninvasive technology: fluorescence microscopy and en-face optical coherence tomography

    Science.gov (United States)

    Marcauteanu, Corina; Negrutiu, Meda; Sinescu, Cosmin; Demjan, Enikö; Hughes, Michael; Bradu, Adrian; Dobre, George; Podoleanu, Adrian G.

    2009-07-01

    The aim of this study is the early detection and monitoring of occlusal overload in bruxing patients. En-Face Optical coherence tomography (eF-OCT) and fluorescence microscopy (FM) were used for the imaging of several anterior teeth extracted from patients with light active bruxism. We found a characteristic pattern of enamel cracks, that reached the tooth surface. We concluded that the combination of the en-Face OCT and FM is a promising non-invasive alternative technique for reliable monitoring of occlusal overload.

  1. Postactivation potentiation biases maximal isometric strength assessment.

    Science.gov (United States)

    Lima, Leonardo Coelho Rabello; Oliveira, Felipe Bruno Dias; Oliveira, Thiago Pires; Assumpção, Claudio de Oliveira; Greco, Camila Coelho; Cardozo, Adalgiso Croscato; Denadai, Benedito Sérgio

    2014-01-01

    Postactivation potentiation (PAP) is known to enhance force production. Maximal isometric strength assessment protocols usually consist of two or more maximal voluntary isometric contractions (MVCs). The objective of this study was to determine if PAP would influence isometric strength assessment. Healthy male volunteers (n = 23) performed two five-second MVCs separated by a 180-seconds interval. Changes in isometric peak torque (IPT), time to achieve it (tPTI), contractile impulse (CI), root mean square of the electromyographic signal during PTI (RMS), and rate of torque development (RTD), in different intervals, were measured. Significant increases in IPT (240.6 ± 55.7 N·m versus 248.9 ± 55.1 N·m), RTD (746 ± 152 N·m·s(-1) versus 727 ± 158 N·m·s(-1)), and RMS (59.1 ± 12.2% RMSMAX  versus 54.8 ± 9.4% RMSMAX) were found on the second MVC. tPTI decreased significantly on the second MVC (2373 ± 1200 ms versus 2784 ± 1226 ms). We conclude that a first MVC leads to PAP that elicits significant enhancements in strength-related variables of a second MVC performed 180 seconds later. If disconsidered, this phenomenon might bias maximal isometric strength assessment, overestimating some of these variables.

  2. Gain maximization in a probabilistic entanglement protocol

    Science.gov (United States)

    di Lorenzo, Antonio; Esteves de Queiroz, Johnny Hebert

    Entanglement is a resource. We can therefore define gain as a monotonic function of entanglement G (E) . If a pair with entanglement E is produced with probability P, the net gain is N = PG (E) - (1 - P) C , where C is the cost of a failed attempt. We study a protocol where a pair of quantum systems is produced in a maximally entangled state ρm with probability Pm, while it is produced in a partially entangled state ρp with the complementary probability 1 -Pm . We mix a fraction w of the partially entangled pairs with the maximally entangled ones, i.e. we take the state to be ρ = (ρm + wUlocρpUloc+) / (1 + w) , where Uloc is an appropriate unitary local operation designed to maximize the entanglement of ρ. This procedure on one hand reduces the entanglement E, and hence the gain, but on the other hand it increases the probability of success to P =Pm + w (1 -Pm) , therefore the net gain N may increase. There may be hence, a priori, an optimal value for w, the fraction of failed attempts that we mix in. We show that, in the hypothesis of a linear gain G (E) = E , even assuming a vanishing cost C -> 0 , the net gain N is increasing with w, therefore the best strategy is to always mix the partially entangled states. Work supported by CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico, proc. 311288/2014-6, and by FAPEMIG, Fundação de Amparo à Pesquisa de Minas Gerais, proc. IC-FAPEMIG2016-0269 and PPM-00607-16.

  3. Maximizing percentage depletion in solid minerals

    International Nuclear Information System (INIS)

    Tripp, J.; Grove, H.D.; McGrath, M.

    1982-01-01

    This article develops a strategy for maximizing percentage depletion deductions when extracting uranium or other solid minerals. The goal is to avoid losing percentage depletion deductions by staying below the 50% limitation on taxable income from the property. The article is divided into two major sections. The first section is comprised of depletion calculations that illustrate the problem and corresponding solutions. The last section deals with the feasibility of applying the strategy and complying with the Internal Revenue Code and appropriate regulations. Three separate strategies or appropriate situations are developed and illustrated. 13 references, 3 figures, 7 tables

  4. What currency do bumble bees maximize?

    Directory of Open Access Journals (Sweden)

    Nicholas L Charlton

    2010-08-01

    Full Text Available In modelling bumble bee foraging, net rate of energetic intake has been suggested as the appropriate currency. The foraging behaviour of honey bees is better predicted by using efficiency, the ratio of energetic gain to expenditure, as the currency. We re-analyse several studies of bumble bee foraging and show that efficiency is as good a currency as net rate in terms of predicting behaviour. We suggest that future studies of the foraging of bumble bees should be designed to distinguish between net rate and efficiency maximizing behaviour in an attempt to discover which is the more appropriate currency.

  5. New Maximal Two-distance Sets

    DEFF Research Database (Denmark)

    Lisonek, Petr

    1996-01-01

    A two-distance set in E^d is a point set X inthe d-dimensional Euclidean spacesuch that the distances between distinct points in Xassume only two different non-zero values. Based on results from classical distance geometry, we developan algorithm to classify, for a given dimension, all maximal...... (largest possible)two-distance sets in E^d.Using this algorithm we have completed the full classificationfor all dimensions less than or equal to 7, andwe have found one set in E^8 whosemaximality follows from Blokhuis' upper bound on sizes of s-distance sets.While in the dimensions less than or equal to 6...

  6. Maximizing policy learning in international committees

    DEFF Research Database (Denmark)

    Nedergaard, Peter

    2007-01-01

    , this article demonstrates that valuable lessons can be learned about policy learning, in practice and theoretically, by analysing the cooperation in the OMC committees. Using the Advocacy Coalition Framework as the starting point of analysis, 15 hypotheses on policy learning are tested. Among other things......, it is concluded that in order to maximize policy learning in international committees, empirical data should be made available to committees and provided by sources close to the participants (i.e. the Commission). In addition, the work in the committees should be made prestigious in order to attract well...

  7. Pouliot type duality via a-maximization

    International Nuclear Information System (INIS)

    Kawano, Teruhiko; Ookouchi, Yutaka; Tachikawa, Yuji; Yagi, Futoshi

    2006-01-01

    We study four-dimensional N=1Spin(10) gauge theory with a single spinor and N Q vectors at the superconformal fixed point via the electric-magnetic duality and a-maximization. When gauge invariant chiral primary operators hit the unitarity bounds, we find that the theory with no superpotential is identical to the one with some superpotential at the infrared fixed point. The auxiliary field method in the electric theory offers a satisfying description of the infrared fixed point, which is consistent with the better picture in the magnetic theory. In particular, it gives a clear description of the emergence of new massless degrees of freedom in the electric theory

  8. Developing maximal neuromuscular power: part 2 - training considerations for improving maximal power production.

    Science.gov (United States)

    Cormie, Prue; McGuigan, Michael R; Newton, Robert U

    2011-02-01

    This series of reviews focuses on the most important neuromuscular function in many sport performances: the ability to generate maximal muscular power. Part 1, published in an earlier issue of Sports Medicine, focused on the factors that affect maximal power production while part 2 explores the practical application of these findings by reviewing the scientific literature relevant to the development of training programmes that most effectively enhance maximal power production. The ability to generate maximal power during complex motor skills is of paramount importance to successful athletic performance across many sports. A crucial issue faced by scientists and coaches is the development of effective and efficient training programmes that improve maximal power production in dynamic, multi-joint movements. Such training is referred to as 'power training' for the purposes of this review. Although further research is required in order to gain a deeper understanding of the optimal training techniques for maximizing power in complex, sports-specific movements and the precise mechanisms underlying adaptation, several key conclusions can be drawn from this review. First, a fundamental relationship exists between strength and power, which dictates that an individual cannot possess a high level of power without first being relatively strong. Thus, enhancing and maintaining maximal strength is essential when considering the long-term development of power. Second, consideration of movement pattern, load and velocity specificity is essential when designing power training programmes. Ballistic, plyometric and weightlifting exercises can be used effectively as primary exercises within a power training programme that enhances maximal power. The loads applied to these exercises will depend on the specific requirements of each particular sport and the type of movement being trained. The use of ballistic exercises with loads ranging from 0% to 50% of one-repetition maximum (1RM) and

  9. 30 CFR 77.506-1 - Electric equipment and circuits; overload and short circuit protection; minimum requirements.

    Science.gov (United States)

    2010-07-01

    ... short circuit protection; minimum requirements. 77.506-1 Section 77.506-1 Mineral Resources MINE SAFETY...-1 Electric equipment and circuits; overload and short circuit protection; minimum requirements. Devices providing either short circuit protection or protection against overload shall conform to the...

  10. Work Processes, Role Conflict, and Role Overload: The Case of Nurses and Engineers in the Public Sector.

    Science.gov (United States)

    Bacharach, Samuel B.; And Others

    1990-01-01

    Study of five sets of work process variables and their relationship to role conflict and overload among public sector nurses and engineers found managerial strategies appropriate for minimizing role conflict not necessarily appropriate for minimizing role overload. Some work process predictors may be similar across professions, and managerial…

  11. Reducing Information Overload in Large Seismic Data Sets

    Energy Technology Data Exchange (ETDEWEB)

    HAMPTON,JEFFERY W.; YOUNG,CHRISTOPHER J.; MERCHANT,BION J.; CARR,DORTHE B.; AGUILAR-CHANG,JULIO

    2000-08-02

    Event catalogs for seismic data can become very large. Furthermore, as researchers collect multiple catalogs and reconcile them into a single catalog that is stored in a relational database, the reconciled set becomes even larger. The sheer number of these events makes searching for relevant events to compare with events of interest problematic. Information overload in this form can lead to the data sets being under-utilized and/or used incorrectly or inconsistently. Thus, efforts have been initiated to research techniques and strategies for helping researchers to make better use of large data sets. In this paper, the authors present their efforts to do so in two ways: (1) the Event Search Engine, which is a waveform correlation tool and (2) some content analysis tools, which area combination of custom-built and commercial off-the-shelf tools for accessing, managing, and querying seismic data stored in a relational database. The current Event Search Engine is based on a hierarchical clustering tool known as the dendrogram tool, which is written as a MatSeis graphical user interface. The dendrogram tool allows the user to build dendrogram diagrams for a set of waveforms by controlling phase windowing, down-sampling, filtering, enveloping, and the clustering method (e.g. single linkage, complete linkage, flexible method). It also allows the clustering to be based on two or more stations simultaneously, which is important to bridge gaps in the sparsely recorded event sets anticipated in such a large reconciled event set. Current efforts are focusing on tools to help the researcher winnow the clusters defined using the dendrogram tool down to the minimum optimal identification set. This will become critical as the number of reference events in the reconciled event set continually grows. The dendrogram tool is part of the MatSeis analysis package, which is available on the Nuclear Explosion Monitoring Research and Engineering Program Web Site. As part of the research

  12. Maximization techniques for oilfield development profits

    International Nuclear Information System (INIS)

    Lerche, I.

    1999-01-01

    In 1981 Nind provided a quantitative procedure for estimating the optimum number of development wells to emplace on an oilfield to maximize profit. Nind's treatment assumed that there was a steady selling price, that all wells were placed in production simultaneously, and that each well's production profile was identical and a simple exponential decline with time. This paper lifts these restrictions to allow for price fluctuations, variable with time emplacement of wells, and production rates that are more in line with actual production records than is a simple exponential decline curve. As a consequence, it is possible to design production rate strategies, correlated with price fluctuations, so as to maximize the present-day worth of a field. For price fluctuations that occur on a time-scale rapid compared to inflation rates it is appropriate to have production rates correlate directly with such price fluctuations. The same strategy does not apply for price fluctuations occurring on a time-scale long compared to inflation rates where, for small amplitudes in the price fluctuations, it is best to sell as much product as early as possible to overcome inflation factors, while for large amplitude fluctuations the best strategy is to sell product as early as possible but to do so mainly on price upswings. Examples are provided to show how these generalizations of Nind's (1981) formula change the complexion of oilfield development optimization. (author)

  13. Diagnosis, management and response criteria of iron overload in myelodysplastic syndromes (MDS): updated recommendations of the Austrian MDS platform.

    Science.gov (United States)

    Valent, Peter; Stauder, Reinhard; Theurl, Igor; Geissler, Klaus; Sliwa, Thamer; Sperr, Wolfgang R; Bettelheim, Peter; Sill, Heinz; Pfeilstöcker, Michael

    2018-02-01

    Despite the availability of effective iron chelators, transfusion-related morbidity is still a challenge in chronically transfused patients with myelodysplastic syndromes (MDS). In these patients, transfusion-induced iron overload may lead to organ dysfunction or even organ failure. In addition, iron overload is associated with reduced overall survival in MDS. Areas covered: During the past 10 years, various guidelines for the management of MDS patients with iron overload have been proposed. In the present article, we provide our updated recommendations for the diagnosis, prevention and therapy of iron overload in MDS. In addition, we propose refined treatment response criteria. As in 2006 and 2007, recommendations were discussed and formulated by participants of our Austrian MDS platform in a series of meetings in 2016 and 2017. Expert commentary: Our updated recommendations should support early recognition of iron overload, optimal patient management and the measurement of clinical responses to chelation treatment in daily practice.

  14. Al-hijamah and oral honey for treating thalassemia, conditions of iron overload, and hyperferremia: toward improving the therapeutic outcomes

    Science.gov (United States)

    El Sayed, Salah Mohamed; Baghdadi, Hussam; Abou-Taleb, Ashraf; Mahmoud, Hany Salah; Maria, Reham A; Ahmed, Nagwa S; Helmy Nabo, Manal Mohamed

    2014-01-01

    Iron overload causes iron deposition and accumulation in the liver, heart, skin, and other tissues resulting in serious tissue damages. Significant blood clearance from iron and ferritin using wet cupping therapy (WCT) has been reported. WCT is an excretory form of treatment that needs more research efforts. WCT is an available, safe, simple, economic, and time-saving outpatient modality of treatment that has no serious side effects. There are no serious limitations or precautions to discontinue WCT. Interestingly, WCT has solid scientific and medical bases (Taibah mechanism) that explain its effectiveness in treating many disease conditions differing in etiology and pathogenesis. WCT utilizes an excretory physiological principle (pressure-dependent excretion) that resembles excretion through renal glomerular filtration and abscess evacuation. WCT exhibits a percutaneous excretory function that clears blood (through fenestrated skin capillaries) and interstitial fluids from pathological substances without adding a metabolic or detoxification burden on the liver and the kidneys. Interestingly, WCT was reported to decrease serum ferritin (circulating iron stores) significantly by about 22.25% in healthy subjects (in one session) and to decrease serum iron significantly to the level of causing iron deficiency (in multiple sessions). WCT was reported to clear blood significantly of triglycerides, low-density lipoprotein (LDL) cholesterol, total cholesterol, uric acid, inflammatory mediators, and immunoglobulin antibodies (rheumatoid factor). Moreover, WCT was reported to enhance the natural immunity, potentiate pharmacological treatments, and to treat many different disease conditions. There are two distinct methods of WCT: traditional WCT and Al-hijamah (WCT of prophetic medicine). Both start and end with skin sterilization. In traditional WCT, there are two steps, skin scarification followed by suction using plastic cups (double S technique); Al-hijamah is a three

  15. Fatigue History and in-situ Loading Studies of the overload Effect Using High Resolution X-ray Strain Profiling

    International Nuclear Information System (INIS)

    Croft, M.; Jisrawi, N.; Zhong, Z.; Holtz, R.; Sadananda, K.; Skaritka, J.; Tsakalakos, T.

    2007-01-01

    High-energy synchrotron X-ray diffraction experiments are used to perform local crack plane strain profiling of 4140 steel compact tension specimens fatigued at constant amplitude, subjected to a single overload cycle, then fatigued some more at constant amplitude. X-ray strain profiling results on a series of samples employing in-situ load cycling are correlated with the crack growth rate (da/dN) providing insight into the da/dN retardation known as the 'overload effect'. Immediately after the overload, the strain under maximum load is greatly reduced but the range of strain, between zero and maximum load, remains unchanged compared to the pre-overload values. At the point of maximum retardation, it is the strain range that is greatly reduced while the maximum-load strain has begun to recover to the pre-overload value. For a sample that has recovered to approximately half of the original da/dN value following the overload, the strain at maximum load is fully recovered while the strain range, though partially recovered, is still substantially reduced. The dominance of the strain range in the overload effect is clearly indicated. Subject to some assumptions, strong quantitative support for a crack growth rate driving force of the suggested form [(K max ) -p (ΔK) p ] γ is found. A dramatic nonlinear load dependence in the spatial distribution of the strain at maximum retardation is also demonstrated: at low load the response is dominantly at the overload position; whereas at high loads it is dominantly at the crack tip position. This transfer of load response away from the crack tip to the overload position appears fundamental to the overload effect for high R-ratio fatigue as studied here

  16. When Enough Is Not Enough: Information Overload and Metacognitive Decisions to Stop Studying Information

    Science.gov (United States)

    Murayama, Kou; Blake, Adam B.; Kerr, Tyson; Castel, Alan D.

    2016-01-01

    People are often exposed to more information than they can actually remember. Despite this frequent form of information overload, little is known about how much information people choose to remember. Using a novel "stop" paradigm, the current research examined whether and how people choose to stop receiving new--possibly…

  17. Association between filial responsibility when caring for parents and the caregivers overload

    Directory of Open Access Journals (Sweden)

    Marinês Aires

    Full Text Available ABSTRACT Objective: To analyze the association between filial responsibility and the overload of the children when caring for their older parents. Method: Cross-sectional study with 100 caregiver children of older adults. Filial liability was assessed by the attitudes of the responsible child (scale of expectation and filial duty and by care behaviors (assistance in activities of daily living, emotional and financial support, and keeping company. The overload was assessed by the Caregiver Burden Inventory. To assess the associations, the correlation coefficients of Pearson and Spearman, Kruskal-Wallis Test, and Mann-Whitney were employed. Variables that presented p-value<0.20 in the bivariate analysis were inserted in a multivariate linear regression model. Results: The factors associated with overload were: formal employment (p=0.002, feelings regarding family life (p<0.001, financial support (p=0.027, and assistance with Activities of Daily Living (ADLs (p<0.001. Conclusion: Children who were more involved with the ADLs and provided financial support showed higher levels of overload.

  18. 2D mapping of plane stress crack-tip fields following an overload

    Directory of Open Access Journals (Sweden)

    P. J. Withers

    2015-07-01

    Full Text Available The evolution of crack-tip strain fields in a thin (plane stress compact tension sample following an overload (OL event has been studied using two different experimental techniques. Surface behaviour has been characterised by Digital Image Correlation (DIC, while the bulk behaviour has been characterised by means of synchrotron X-ray diffraction (XRD. The combination of both surface and bulk information allowed us to visualise the through-thickness evolution of the strain fields before the OL event, during the overload event, just after OL and at various stages after it. Unlike previous work, complete 2D maps of strains around the crack-tip were acquired at 60m spatial resolution by XRD. The DIC shows less crack opening after overload and the XRD a lower crack-tip peak stress after OL until the crack has grown past the compressive crack-tip residual stress introduced by the overload after which the behaviour returned to that for the baseline fatigue response. While the peak crack-tip stress is supressed by the compressive residual stress, the crack-tip stress field changes over each cycle are nevertheless the same for all Kmax cycles except at OL.

  19. An Investigation of Data Overload in Team-Based Distributed Cognition Systems

    Science.gov (United States)

    Hellar, David Benjamin

    2009-01-01

    The modern military command center is a hybrid system of computer automated surveillance and human oriented decision making. In these distributed cognition systems, data overload refers simultaneously to the glut of raw data processed by information technology systems and the dearth of actionable knowledge useful to human decision makers.…

  20. The "Tyranny of Choice": Choice Overload as a Possible Instance of Effort Discounting

    Science.gov (United States)

    Reed, Derek D.; Reed, Florence D. DiGennaro; Chok, James; Brozyna, Gary A.

    2011-01-01

    When making a choice, people like to have options, but an emerging literature on "choice overload" suggests that the provision of too many options results in adverse experiences, including a depletion of cognitive resources and postdecision feelings of regret. A strong implication is that individuals should shy away from situations…

  1. 77 FR 11598 - Thermal Overload Protection for Electric Motors on Motor-Operated Valves

    Science.gov (United States)

    2012-02-27

    ... application of thermal overload protection devices that are integral with the motor starter for electric... Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone: 301-251-7455; email... Development Branch, Division of Engineering, Office of Nuclear Regulatory Research. [FR Doc. 2012-4552 Filed 2...

  2. An overload behavior detection system for engineering transport vehicles based on deep learning

    Science.gov (United States)

    Zhou, Libo; Wu, Gang

    2018-04-01

    This paper builds an overloaded truck detect system called ITMD to help traffic department automatically identify the engineering transport vehicles (commonly known as `dirt truck') in CCTV and determine whether the truck is overloaded or not. We build the ITMD system based on the Single Shot MultiBox Detector (SSD) model. By constructing the image dataset of the truck and adjusting hyper-parameters of the original SSD neural network, we successfully trained a basic network model which the ITMD system depends on. The basic ITMD system achieves 83.01% mAP on classifying overload/non-overload truck, which is a not bad result. Still, some shortcomings of basic ITMD system have been targeted to enhance: it is easy for the ITMD system to misclassify other similar vehicle as truck. In response to this problem, we optimized the basic ITMD system, which effectively reduced basic model's false recognition rate. The optimized ITMD system achieved 86.18% mAP on the test set, which is better than the 83.01% mAP of the basic ITMD system.

  3. Fatty emaciation: a case report of suspected fat overload syndrome in oral refeeding.

    Science.gov (United States)

    Macher, Arielle D; Palazuelos, Daniel; Maviglia, Saverio M

    2012-07-01

    Refeeding syndrome has been observed in patients receiving nutrition after a prolonged period of malnourishment and is characterized by multiple metabolic derangements. Besides hypophosphatemia and hypoglycemia, lipemia has been described in association with parenteral nutrition administration to the malnourished. The authors describe one anorexic patient who developed lipemia during oral refeeding, followed by a precipitous drop in hematocrit suggestive of fat overload syndrome.

  4. Global transcriptional response to Hfe deficiency and dietary iron overload in mouse liver and duodenum.

    Directory of Open Access Journals (Sweden)

    Alejandra Rodriguez

    2009-09-01

    Full Text Available Iron is an essential trace element whose absorption is usually tightly regulated in the duodenum. HFE-related hereditary hemochromatosis (HH is characterized by abnormally low expression of the iron-regulatory hormone, hepcidin, which results in increased iron absorption. The liver is crucial for iron homeostasis as it is the main production site of hepcidin. The aim of this study was to explore and compare the genome-wide transcriptome response to Hfe deficiency and dietary iron overload in murine liver and duodenum. Illumina arrays containing over 47,000 probes were used to study global transcriptional changes. Quantitative RT-PCR (Q-RT-PCR was used to validate the microarray results. In the liver, the expression of 151 genes was altered in Hfe(-/- mice while dietary iron overload changed the expression of 218 genes. There were 173 and 108 differentially expressed genes in the duodenum of Hfe(-/- mice and mice with dietary iron overload, respectively. There was 93.5% concordance between the results obtained by microarray analysis and Q-RT-PCR. Overexpression of genes for acute phase reactants in the liver and a strong induction of digestive enzyme genes in the duodenum were characteristic of the Hfe-deficient genotype. In contrast, dietary iron overload caused a more pronounced change of gene expression responsive to oxidative stress. In conclusion, Hfe deficiency caused a previously unrecognized increase in gene expression of hepatic acute phase proteins and duodenal digestive enzymes.

  5. Iron Overload Leading to Torsades de Pointes in β-Thalassemia and Long QT Syndrome

    DEFF Research Database (Denmark)

    Refaat, Marwan M; El Hage, Lea; Steffensen, Annette Buur

    2016-01-01

    The authors present a unique case of torsades de pointes in a β-thalassemia patient with early iron overload in the absence of any structural abnormalities as seen in hemochromatosis. Genetic testing showed a novel KCNQ1 gene mutation 1591C>T [Gln531Ter(X)]. Testing of the gene mutation in Xenopus...

  6. 30 CFR 77.506 - Electric equipment and circuits; overload and short-circuit protection.

    Science.gov (United States)

    2010-07-01

    ... short-circuit protection. 77.506 Section 77.506 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... circuits; overload and short-circuit protection. Automatic circuit-breaking devices or fuses of the correct type and capacity shall be installed so as to protect all electric equipment and circuits against short...

  7. Technologies for dealing with information overload : an engineers' point of view

    NARCIS (Netherlands)

    Calders, T.G.K.; Fletcher, G.H.L.; Kamiran, F.; Pechenizkiy, M.; Strother, J.B.; Ulijn, J.M.; Fazal, Z.

    2012-01-01

    In this chapter, we provide an overview of the technological side of the information overload problem. We discuss the challenges and opportunities offered by the ever-growing and emerging stream of information from an engineering point of view. More concretely, we survey storage and querying

  8. Competitive On-Line Scheduling for Overloaded Real-Time Systems

    Science.gov (United States)

    1993-09-01

    Real - Time Systems by Gilad Koren a dissertation submitted in partial fulfillment of the requirements...Overloaded Real - Time Systems 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK...1.1 Introduction : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2 1.1.1 Real - Time Systems : : : : : : : : : : : : : : : : : : : : : : : : : : : :

  9. Iron overload in very low birth weight infants: Serum Ferritin and adverse outcomes

    LENUS (Irish Health Repository)

    Barrett, M

    2011-11-01

    Adequate iron isessential for growth and haematpoiesis. Oral iron supplementation is the standard of care in VLBW infants. Post mortem evidence has confirmed significant iron overload. Excessive free iron has been associated with free radical formation and brain injury in term infants.

  10. Role of metabolic overload and metabolic inflammation in the development of Nonalcoholic Steatohepatitis (NASH)

    NARCIS (Netherlands)

    Liang, W.

    2015-01-01

    Overload of nutrients can lead to diet-induced inflammation, also called metabolic inflammation, which is thought to play an important role in many metabolic diseases, including the development of nonalcoholic fatty liver disease (NAFLD). NAFLD encompasses a spectrum of pathologies that range from

  11. Fear of Success: A Personality Trait or a Response to Occupational Deviance and Role Overload?

    Science.gov (United States)

    Bremer, Teresa Hargrave; Wittig, Michele Andrisin

    1980-01-01

    Clarifies the extent to which an individual's fear of success scores may vary with the presence or absence of occupational deviance and/or role overload in stimulus materials describing situations of female competitive success. Results suggest that fear of success is a misnomer for responses to women's role descriptions. (Author/JLF)

  12. A low noise preamplifier with optoelectronic overload protection for radioactivity measurement

    International Nuclear Information System (INIS)

    Sephton, J.P.; Williams, J.M.; Johansson, L.C.; Philips, H.C.

    2012-01-01

    Pulses from detectors used for radioactivity measurement can vary in size by several orders of magnitude. Large pulses will lead to saturation at the preamplifier output and extension of the pulse length. As a consequence, the dead time of the system increases and pulses may be lost. Electronic design techniques employed to protect against overloading tend to increase the amplifier noise level. However, an optoelectronic method of overload protection has been devised which has only a negligible effect on noise. An infrared light emitting diode interfaced to the output of the preamplifier is linked by fibre optic cable to an ultra-low leakage photodiode at the input. The conduction of the photodiode increases with the amplitude of the preamplifier output signal. Excess current is thereby prevented from entering the preamplifier and causing saturation. The preamplifier has been tested on 4π beta–gamma and gas counting systems and found to give good protection against overloading. - Highlights: ► A preamplifier for radioactivity measurements has been developed. ► Low noise. ► Current sensitive. ► Optoelectronic overload protection.

  13. The role of magnetic resonance imaging in the evaluation of transfusional iron overload in myelodysplastic syndromes.

    Science.gov (United States)

    Petrou, Emmanouil; Mavrogeni, Sophie; Karali, Vasiliki; Kolovou, Genovefa; Kyrtsonis, Marie-Christine; Sfikakis, Petros P; Panayiotidis, Panayiotis

    2015-01-01

    Myelodysplastic syndromes represent a group of heterogeneous hematopoietic neoplasms derived from an abnormal multipotent progenitor cell, characterized by a hyperproliferative bone marrow, dysplasia of the cellular hemopoietic elements and ineffective erythropoiesis. Anemia is a common finding in myelodysplastic syndrome patients, and blood transfusions are the only therapeutic option in approximately 40% of cases. The most serious side effect of regular blood transfusion is iron overload. Currently, cardiovascular magnetic resonance using T2 is routinely used to identify patients with myocardial iron overload and to guide chelation therapy, tailored to prevent iron toxicity in the heart. This is a major validated non-invasive measure of myocardial iron overloading and is superior to surrogates such as serum ferritin, liver iron, ventricular ejection fraction and tissue Doppler parameters. The indication for iron chelation therapy in myelodysplastic syndrome patients is currently controversial. However, cardiovascular magnetic resonance may offer an excellent non-invasive, diagnostic tool for iron overload assessment in myelodysplastic syndromes. Further studies are needed to establish the precise indications of chelation therapy and the clinical implications of this treatment on survival in myelodysplastic syndromes. Copyright © 2014 Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular. Published by Elsevier Editora Ltda. All rights reserved.

  14. Effect of tensile overloads on fatigue crack growth of high strength steel wires

    International Nuclear Information System (INIS)

    Haag, J.; Reguly, A.; Strohaecker, T.R.

    2013-01-01

    Highlights: • A proof load process may be an option to increase the fatigue life of flexible pipelines. • There is possibility to produce plastic deformation at crack tip of tensile armor wires. • Controlled overloads provide effective crack growth retardation. • Crack growth retardation is also evident at higher stress ratios. - Abstract: Fatigue of the tensile armor wires is the main failure mode of flexible risers. Techniques to increase the life of these components are required to improve the processes safety on oil exploration. This work evaluates the crack growth retardation of high strength steel wires used in flexible pipelines. Fracture toughness tests were performed to establish the level of stress intensity factor wherein the wires present significant plastic deformation at the crack tip. The effect of tensile overload on fatigue behavior was assessed by fatigue crack growth testing under constant ΔK control and different overload ratios with two different load ratios. The outcomes show that the application of controlled overloads provides crack retardation and increases the fatigue life of the wires more than 31%. This behavior is also evident at stress ratio of 0.5, in spite of the crack closure effect being minimized by increasing the applied mean stress

  15. Diagnosis of hepatic iron overload: a family study illustrating pitfalls in diagnosing hemochromatosis.

    Science.gov (United States)

    Schranz, Melanie; Talasz, Heribert; Graziadei, Ivo; Winder, Thomas; Sergi, Consolato; Bogner, Klaus; Vogel, Wolfgang; Zoller, Heinz

    2009-03-01

    Recent identification of genetic variants in iron storage disease has changed the classification system and diagnostic algorithms for hemochromatosis. Clinical diagnosis of the disease requires phenotypic evidence of iron overload because the commonly disease-associated HFE genotypes have an incomplete penetrance. Furthermore, approximately 20% of patients with a clinical diagnosis of hemochromatosis have no disease-associated genotype, which underlines the importance of clear phenotypic criteria of hemochromatosis. A diagnosis of hemochromatosis cannot be made even in patients with liver cirrhosis simply on the basis of genetic testing that indicates that iron overload is the cause of the disease and not its consequence. Proper diagnosis requires integration of clinical presentation, family history, and the results of biochemical and histopathologic tests. Here we propose a rational diagnostic algorithm for hepatic iron overload syndromes and illustrate potential pitfalls by presenting a family study in a pedigree with rare HFE variants (H63D and E168Q), in cis on the same chromosome. Although the clinical suspicion of hemochromatosis was confirmed by histology, chemical analysis of liver tissue revealed a normal hepatic iron concentration, which is compatible with the genetic finding of 1 normal and 1 doubly mutated allele. In conclusion, clinical suspicion of hemochromatosis and elevated serum iron parameters should prompt HFE genotyping for C282Y and H63D. Should they be uninformative, further genetic tests should be recommended only if iron overload in liver tissue has been confirmed chemically.

  16. The spring balance: a simple monitoring system for fluid overload during hysteroscopic surgery

    NARCIS (Netherlands)

    Ankum, W. M.; Vonk, J.

    1994-01-01

    Fluid overload may arise during hysteroscopic surgery, caused by absorption of fluid used to distend the uterus. Continuous monitoring of the fluid balance is required to prevent this serious complication. Commercial equipment does not serve this purpose adequately. We describe a simple solution. We

  17. Iron overload of human colon adenocarcinoma cells studied by synchrotron-based X-ray techniques

    NARCIS (Netherlands)

    Mihucz, Victor G.; Meirer, Florian; Polgári, Zsófia; Réti, Andrea; Pepponi, Giancarlo; Ingerle, Dieter; Szoboszlai, Norbert; Streli, Christina

    2016-01-01

    Fast- and slow-proliferating human adenocarcinoma colorectal cells, HT-29 and HCA-7, respectively, overloaded with transferrin (Tf), Fe(III) citrate, Fe(III) chloride and Fe(II) sulfate were studied by synchrotron radiation total-reflection X-ray spectrometry (TXRF), TXRF-X-ray absorption near edge

  18. Shareholder, stakeholder-owner or broad stakeholder maximization

    DEFF Research Database (Denmark)

    Mygind, Niels

    2004-01-01

    With reference to the discussion about shareholder versus stakeholder maximization it is argued that the normal type of maximization is in fact stakeholder-owner maxi-mization. This means maximization of the sum of the value of the shares and stake-holder benefits belonging to the dominating...... including the shareholders of a company. Although it may be the ultimate goal for Corporate Social Responsibility to achieve this kind of maximization, broad stakeholder maximization is quite difficult to give a precise definition. There is no one-dimensional measure to add different stakeholder benefits...... not traded on the mar-ket, and therefore there is no possibility for practical application. Broad stakeholder maximization instead in practical applications becomes satisfying certain stakeholder demands, so that the practical application will be stakeholder-owner maximization un-der constraints defined...

  19. Mice lacking liver-specific β-catenin develop steatohepatitis and fibrosis after iron overload.

    Science.gov (United States)

    Preziosi, Morgan E; Singh, Sucha; Valore, Erika V; Jung, Grace; Popovic, Branimir; Poddar, Minakshi; Nagarajan, Shanmugam; Ganz, Tomas; Monga, Satdarshan P

    2017-08-01

    Iron overload disorders such as hereditary hemochromatosis and iron loading anemias are a common cause of morbidity from liver diseases and increase risk of hepatic fibrosis and hepatocellular carcinoma (HCC). Treatment options for iron-induced damage are limited, partly because there is lack of animal models of human disease. Therefore, we investigated the effect of iron overload in liver-specific β-catenin knockout mice (KO), which are susceptible to injury, fibrosis and tumorigenesis following chemical carcinogen exposure. Iron overload diet was administered to KO and littermate control (CON) mice for various times. To ameliorate an oxidant-mediated component of tissue injury, N-Acetyl-L-(+)-cysteine (NAC) was added to drinking water of mice on iron overload diet. KO on iron diet (KO +Fe) exhibited remarkable inflammation, followed by steatosis, oxidative stress, fibrosis, regenerating nodules and occurrence of occasional HCC. Increased injury in KO +Fe was associated with activated protein kinase B (AKT), ERK, and NF-κB, along with reappearance of β-catenin and target gene Cyp2e1, which promoted lipid peroxidation and hepatic damage. Addition of NAC to drinking water protected KO +Fe from hepatic steatosis, injury and fibrosis, and prevented activation of AKT, ERK, NF-κB and reappearance of β-catenin. The absence of hepatic β-catenin predisposes mice to hepatic injury and fibrosis following iron overload, which was reminiscent of hemochromatosis and associated with enhanced steatohepatitis and fibrosis. Disease progression was notably alleviated by antioxidant therapy, which supports its chemopreventive role in the management of chronic iron overload disorders. Lack of animal models for iron overload disorders makes it hard to study the disease process for improving therapies. Feeding high iron diet to mice that lack the β-catenin gene in liver cells led to increased inflammation followed by fat accumulation, cell death and wound healing that mimicked

  20. Fluid Overload and Cumulative Thoracostomy Output Are Associated With Surgical Site Infection After Pediatric Cardiothoracic Surgery.

    Science.gov (United States)

    Sochet, Anthony A; Nyhan, Aoibhinn; Spaeder, Michael C; Cartron, Alexander M; Song, Xiaoyan; Klugman, Darren; Brown, Anna T

    2017-08-01

    To determine the impact of cumulative, postoperative thoracostomy output, amount of bolus IV fluids and peak fluid overload on the incidence and odds of developing a deep surgical site infection following pediatric cardiothoracic surgery. A single-center, nested, retrospective, matched case-control study. A 26-bed cardiac ICU in a 303-bed tertiary care pediatric hospital. Cases with deep surgical site infection following cardiothoracic surgery were identified retrospectively from January 2010 through December 2013 and individually matched to controls at a ratio of 1:2 by age, gender, Risk Adjustment for Congenital Heart Surgery score, Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery category, primary cardiac diagnosis, and procedure. None. Twelve cases with deep surgical site infection were identified and matched to 24 controls without detectable differences in perioperative clinical characteristics. Deep surgical site infection cases had larger thoracostomy output and bolus IV fluid volumes at 6, 24, and 48 hours postoperatively compared with controls. For every 1 mL/kg of thoracostomy output, the odds of developing a deep surgical site infection increase by 13%. By receiver operative characteristic curve analysis, a cutoff of 49 mL/kg of thoracostomy output at 48 hours best discriminates the development of deep surgical site infection (sensitivity 83%, specificity 83%). Peak fluid overload was greater in cases than matched controls (12.5% vs 6%; p operative characteristic curve analysis, a threshold value of 10% peak fluid overload was observed to identify deep surgical site infection (sensitivity 67%, specificity 79%). Conditional logistic regression of peak fluid overload greater than 10% on the development of deep surgical site infection yielded an odds ratio of 9.4 (95% CI, 2-46.2). Increased postoperative peak fluid overload and cumulative thoracostomy output were associated with deep surgical site infection after pediatric

  1. Primordial two-component maximally symmetric inflation

    Science.gov (United States)

    Enqvist, K.; Nanopoulos, D. V.; Quirós, M.; Kounnas, C.

    1985-12-01

    We propose a two-component inflation model, based on maximally symmetric supergravity, where the scales of reheating and the inflation potential at the origin are decoupled. This is possible because of the second-order phase transition from SU(5) to SU(3)×SU(2)×U(1) that takes place when φ≅φcinflation at the global minimum, and leads to a reheating temperature TR≅(1015-1016) GeV. This makes it possible to generate baryon asymmetry in the conventional way without any conflict with experimental data on proton lifetime. The mass of the gravitinos is m3/2≅1012 GeV, thus avoiding the gravitino problem. Monopoles are diluted by residual inflation in the broken phase below the cosmological bounds if φcUSA.

  2. Distributed-Memory Fast Maximal Independent Set

    Energy Technology Data Exchange (ETDEWEB)

    Kanewala Appuhamilage, Thejaka Amila J.; Zalewski, Marcin J.; Lumsdaine, Andrew

    2017-09-13

    The Maximal Independent Set (MIS) graph problem arises in many applications such as computer vision, information theory, molecular biology, and process scheduling. The growing scale of MIS problems suggests the use of distributed-memory hardware as a cost-effective approach to providing necessary compute and memory resources. Luby proposed four randomized algorithms to solve the MIS problem. All those algorithms are designed focusing on shared-memory machines and are analyzed using the PRAM model. These algorithms do not have direct efficient distributed-memory implementations. In this paper, we extend two of Luby’s seminal MIS algorithms, “Luby(A)” and “Luby(B),” to distributed-memory execution, and we evaluate their performance. We compare our results with the “Filtered MIS” implementation in the Combinatorial BLAS library for two types of synthetic graph inputs.

  3. Quench dynamics of topological maximally entangled states.

    Science.gov (United States)

    Chung, Ming-Chiang; Jhu, Yi-Hao; Chen, Pochung; Mou, Chung-Yu

    2013-07-17

    We investigate the quench dynamics of the one-particle entanglement spectra (OPES) for systems with topologically nontrivial phases. By using dimerized chains as an example, it is demonstrated that the evolution of OPES for the quenched bipartite systems is governed by an effective Hamiltonian which is characterized by a pseudospin in a time-dependent pseudomagnetic field S(k,t). The existence and evolution of the topological maximally entangled states (tMESs) are determined by the winding number of S(k,t) in the k-space. In particular, the tMESs survive only if nontrivial Berry phases are induced by the winding of S(k,t). In the infinite-time limit the equilibrium OPES can be determined by an effective time-independent pseudomagnetic field Seff(k). Furthermore, when tMESs are unstable, they are destroyed by quasiparticles within a characteristic timescale in proportion to the system size.

  4. Maximizing policy learning in international committees

    DEFF Research Database (Denmark)

    Nedergaard, Peter

    2007-01-01

    , this article demonstrates that valuable lessons can be learned about policy learning, in practice and theoretically, by analysing the cooperation in the OMC committees. Using the Advocacy Coalition Framework as the starting point of analysis, 15 hypotheses on policy learning are tested. Among other things......In the voluminous literature on the European Union's open method of coordination (OMC), no one has hitherto analysed on the basis of scholarly examination the question of what contributes to the learning processes in the OMC committees. On the basis of a questionnaire sent to all participants......, it is concluded that in order to maximize policy learning in international committees, empirical data should be made available to committees and provided by sources close to the participants (i.e. the Commission). In addition, the work in the committees should be made prestigious in order to attract well...

  5. Lovelock black holes with maximally symmetric horizons

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Hideki; Willison, Steven; Ray, Sourya, E-mail: hideki@cecs.cl, E-mail: willison@cecs.cl, E-mail: ray@cecs.cl [Centro de Estudios CientIficos (CECs), Casilla 1469, Valdivia (Chile)

    2011-08-21

    We investigate some properties of n( {>=} 4)-dimensional spacetimes having symmetries corresponding to the isometries of an (n - 2)-dimensional maximally symmetric space in Lovelock gravity under the null or dominant energy condition. The well-posedness of the generalized Misner-Sharp quasi-local mass proposed in the past study is shown. Using this quasi-local mass, we clarify the basic properties of the dynamical black holes defined by a future outer trapping horizon under certain assumptions on the Lovelock coupling constants. The C{sup 2} vacuum solutions are classified into four types: (i) Schwarzschild-Tangherlini-type solution; (ii) Nariai-type solution; (iii) special degenerate vacuum solution; and (iv) exceptional vacuum solution. The conditions for the realization of the last two solutions are clarified. The Schwarzschild-Tangherlini-type solution is studied in detail. We prove the first law of black-hole thermodynamics and present the expressions for the heat capacity and the free energy.

  6. MAXIMIZING THE BENEFITS OF ERP SYSTEMS

    Directory of Open Access Journals (Sweden)

    Paulo André da Conceição Menezes

    2010-04-01

    Full Text Available The ERP (Enterprise Resource Planning systems have been consolidated in companies with different sizes and sectors, allowing their real benefits to be definitively evaluated. In this study, several interactions have been studied in different phases, such as the strategic priorities and strategic planning defined as ERP Strategy; business processes review and the ERP selection in the pre-implementation phase, the project management and ERP adaptation in the implementation phase, as well as the ERP revision and integration efforts in the post-implementation phase. Through rigorous use of case study methodology, this research led to developing and to testing a framework for maximizing the benefits of the ERP systems, and seeks to contribute for the generation of ERP initiatives to optimize their performance.

  7. Maximal energy extraction under discrete diffusive exchange

    Energy Technology Data Exchange (ETDEWEB)

    Hay, M. J., E-mail: hay@princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States); Schiff, J. [Department of Mathematics, Bar-Ilan University, Ramat Gan 52900 (Israel); Fisch, N. J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States); Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2015-10-15

    Waves propagating through a bounded plasma can rearrange the densities of states in the six-dimensional velocity-configuration phase space. Depending on the rearrangement, the wave energy can either increase or decrease, with the difference taken up by the total plasma energy. In the case where the rearrangement is diffusive, only certain plasma states can be reached. It turns out that the set of reachable states through such diffusive rearrangements has been described in very different contexts. Building upon those descriptions, and making use of the fact that the plasma energy is a linear functional of the state densities, the maximal extractable energy under diffusive rearrangement can then be addressed through linear programming.

  8. Maximizing profitability in a hospital outpatient pharmacy.

    Science.gov (United States)

    Jorgenson, J A; Kilarski, J W; Malatestinic, W N; Rudy, T A

    1989-07-01

    This paper describes the strategies employed to increase the profitability of an existing ambulatory pharmacy operated by the hospital. Methods to generate new revenue including implementation of a home parenteral therapy program, a home enteral therapy program, a durable medical equipment service, and home care disposable sales are described. Programs to maximize existing revenue sources such as increasing the capture rate on discharge prescriptions, increasing "walk-in" prescription traffic and increasing HMO prescription volumes are discussed. A method utilized to reduce drug expenditures is also presented. By minimizing expenses and increasing the revenues for the ambulatory pharmacy operation, net profit increased from +26,000 to over +140,000 in one year.

  9. Maximizing the benefits of a dewatering system

    International Nuclear Information System (INIS)

    Matthews, P.; Iverson, T.S.

    1999-01-01

    The use of dewatering systems in the mining, industrial sludge and sewage waste treatment industries is discussed, also describing some of the problems that have been encountered while using drilling fluid dewatering technology. The technology is an acceptable drilling waste handling alternative but it has had problems associated with recycled fluid incompatibility, high chemical costs and system inefficiencies. This paper discussed the following five action areas that can maximize the benefits and help reduce costs of a dewatering project: (1) co-ordinate all services, (2) choose equipment that fits the drilling program, (3) match the chemical treatment with the drilling fluid types, (4) determine recycled fluid compatibility requirements, and (5) determine the disposal requirements before project start-up. 2 refs., 5 figs

  10. Mixtures of maximally entangled pure states

    Energy Technology Data Exchange (ETDEWEB)

    Flores, M.M., E-mail: mflores@nip.up.edu.ph; Galapon, E.A., E-mail: eric.galapon@gmail.com

    2016-09-15

    We study the conditions when mixtures of maximally entangled pure states remain entangled. We found that the resulting mixed state remains entangled when the number of entangled pure states to be mixed is less than or equal to the dimension of the pure states. For the latter case of mixing a number of pure states equal to their dimension, we found that the mixed state is entangled provided that the entangled pure states to be mixed are not equally weighted. We also found that one can restrict the set of pure states that one can mix from in order to ensure that the resulting mixed state is genuinely entangled. Also, we demonstrate how these results could be applied as a way to detect entanglement in mixtures of the entangled pure states with noise.

  11. Iron homeostasis and its disruption in mouse lung in iron deficiency and overload.

    Science.gov (United States)

    Giorgi, Gisela; D'Anna, María Cecilia; Roque, Marta Elena

    2015-10-01

    What is the central question of this study? The aim was to explore the role and hitherto unclear mechanisms of action of iron proteins in protecting the lung against the harmful effects of iron accumulation and the ability of pulmonary cells to mobilize iron in iron deficiency. What is the main finding and its importance? We show that pulmonary hepcidin appears not to modify cellular iron mobilization in the lung. We propose pathways for supplying iron to the lung in iron deficiency and for protecting the lung against iron excess in iron overload, mediated by the co-ordinated action of iron proteins, such as divalent metal transporter 1, ZRT-IRE-like-protein 14, transferrin receptor, ferritin, haemochromatosis-associated protein and ferroportin. Iron dyshomeostasis is associated with several forms of chronic lung disease, but its mechanisms of action remain to be elucidated. The aim of the present study was to determine the role of the lung in whole-animal models with iron deficiency and iron overload, studying the divalent metal transporter 1 (DMT1), ZRT-IRE-like protein 14 (ZIP14), transferrin receptor (TfR), haemochromatosis-associated protein (HFE), hepcidin, ferritin and ferroportin (FPN) expression. In each model, adult CF1 mice were divided into the following groups (six mice per group): (i) iron-overload model, iron saccharate i.p. and control group (iron adequate), 0.9% NaCl i.p.; and (ii) iron-deficiency model, induced by repeated bleeding, and control group (sham operated). Proteins were assessed by immunohistochemistry and Western blot. In control mice, DMT1 was localized in the cytoplasm of airway cells, and in iron deficiency and overload it was in the apical membrane. Divalent metal transporter 1 and TfR increased in iron deficiency, without changes in iron overload. ZRT-IRE-like protein 14 decreased in airway cells in iron deficiency and increased in iron overload. In iron deficiency, HFE and FPN were immunolocalized close to the apical membrane

  12. Maximally reliable Markov chains under energy constraints.

    Science.gov (United States)

    Escola, Sean; Eisele, Michael; Miller, Kenneth; Paninski, Liam

    2009-07-01

    Signal-to-noise ratios in physical systems can be significantly degraded if the outputs of the systems are highly variable. Biological processes for which highly stereotyped signal generations are necessary features appear to have reduced their signal variabilities by employing multiple processing steps. To better understand why this multistep cascade structure might be desirable, we prove that the reliability of a signal generated by a multistate system with no memory (i.e., a Markov chain) is maximal if and only if the system topology is such that the process steps irreversibly through each state, with transition rates chosen such that an equal fraction of the total signal is generated in each state. Furthermore, our result indicates that by increasing the number of states, it is possible to arbitrarily increase the reliability of the system. In a physical system, however, an energy cost is associated with maintaining irreversible transitions, and this cost increases with the number of such transitions (i.e., the number of states). Thus, an infinite-length chain, which would be perfectly reliable, is infeasible. To model the effects of energy demands on the maximally reliable solution, we numerically optimize the topology under two distinct energy functions that penalize either irreversible transitions or incommunicability between states, respectively. In both cases, the solutions are essentially irreversible linear chains, but with upper bounds on the number of states set by the amount of available energy. We therefore conclude that a physical system for which signal reliability is important should employ a linear architecture, with the number of states (and thus the reliability) determined by the intrinsic energy constraints of the system.

  13. A Criterion to Identify Maximally Entangled Four-Qubit State

    International Nuclear Information System (INIS)

    Zha Xinwei; Song Haiyang; Feng Feng

    2011-01-01

    Paolo Facchi, et al. [Phys. Rev. A 77 (2008) 060304(R)] presented a maximally multipartite entangled state (MMES). Here, we give a criterion for the identification of maximally entangled four-qubit states. Using this criterion, we not only identify some existing maximally entangled four-qubit states in the literature, but also find several new maximally entangled four-qubit states as well. (general)

  14. Maximal lattice free bodies, test sets and the Frobenius problem

    DEFF Research Database (Denmark)

    Jensen, Anders Nedergaard; Lauritzen, Niels; Roune, Bjarke Hammersholt

    Maximal lattice free bodies are maximal polytopes without interior integral points. Scarf initiated the study of maximal lattice free bodies relative to the facet normals in a fixed matrix. In this paper we give an efficient algorithm for computing the maximal lattice free bodies of an integral m...... method is inspired by the novel algorithm by Einstein, Lichtblau, Strzebonski and Wagon and the Groebner basis approach by Roune....

  15. Effect of Andrographolide‭ Extract on Blood Glucose and Lipid Profile in Rats with Secondary Iron Overload

    Directory of Open Access Journals (Sweden)

    َArash Mehri Pirayvatlo

    2017-01-01

    Full Text Available Background & objectives: Iron overload is involved in the pathophysiology of many diseases including diabetes. In fact, the excess iron by creating free radicals makes damage to pancreas and leads to insulin resistance and diabetes. Andrographolide extract has hypoglycemic and antioxidant properties. This study has surveyed the effects of andrographolide on blood glucose and lipid profile in rats with secondary iron overload. Methods: In this experimental study, 36 male Wistar rats were randomly divided into 6 groups: the healthy control group, secondary iron overload group, secondary iron overload groups treated with a dose of 3.5 and 7 mg/kg of andrographolide extract, and andrographolide groups treated with a dose of 3.5 and 7 mg/kg of extract. Iron and extract were injected for 6 and 12 days, respectively. Blood samples were taken for measurement of blood glucose and lipid profiles. Data were analyzed using ANOVA test. Results: The pathological results of samples from liver of animals receiving iron showed that the iron was deposited in the liver tissues. Iron injection significantly increased blood glucose levels compared to healthy control group (p<0.05. In the iron overload group, andrographolide extract with a dose of 3.5 mg/kg or 7 mg/kg significantly decreased blood glucose levels (p<0.05. Iron injections did not increase the serum triglyceride and cholesterollevels. Injections of andrographolide extract with a dose of 3.5 mg/kg and 7 mg/kg, significantly decreased the cholesterol levels compared to iron receiving group (p<0.05. Conclusion: Results of this study showed that the andrographolide with different doses may be effective in the treatment of diabetes by reducing serum glucose and cholesterol levels.

  16. Cardiac iron overload in chronically transfused patients with thalassemia, sickle cell anemia, or myelodysplastic syndrome.

    Directory of Open Access Journals (Sweden)

    Mariane de Montalembert

    Full Text Available The risk and clinical significance of cardiac iron overload due to chronic transfusion varies with the underlying disease. Cardiac iron overload shortens the life expectancy of patients with thalassemia, whereas its effect is unclear in those with myelodysplastic syndromes (MDS. In patients with sickle cell anemia (SCA, iron does not seem to deposit quickly in the heart. Our primary objective was to assess through a multicentric study the prevalence of cardiac iron overload, defined as a cardiovascular magnetic resonance T2*8 ECs in the past year, and age older than 6 years. We included from 9 centers 20 patients with thalassemia, 41 with SCA, and 25 with MDS in 2012-2014. Erythrocytapharesis did not consistently prevent iron overload in patients with SCA. Cardiac iron overload was found in 3 (15% patients with thalassemia, none with SCA, and 4 (16% with MDS. The liver iron content (LIC ranged from 10.4 to 15.2 mg/g dry weight, with no significant differences across groups (P = 0.29. Abnormal T2* was not significantly associated with any of the measures of transfusion or chelation. Ferritin levels showed a strong association with LIC. Non-transferrin-bound iron was high in the thalassemia and MDS groups but low in the SCA group (P<0.001. Hepcidin was low in thalassemia, normal in SCA, and markedly elevated in MDS (P<0.001. Two mechanisms may explain that iron deposition largely spares the heart in SCA: the high level of erythropoiesis recycles the iron and the chronic inflammation retains iron within the macrophages. Thalassemia, in contrast, is characterized by inefficient erythropoiesis, unable to handle free iron. Iron accumulation varies widely in MDS syndromes due to the competing influences of abnormal erythropoiesis, excess iron supply, and inflammation.

  17. Incidental splenic nodules found on MR imaging done for assessment of iron overload in children

    International Nuclear Information System (INIS)

    Ahyad, Rayan A.; Lam, Christopher Z.; Navarro, Oscar M.; Shearkhani, Omid

    2017-01-01

    MR imaging is used to assess iron overload in patients with hemoglobinopathies and in those who have undergone multiple blood transfusions. Sometimes splenic nodules are found incidentally on these examinations and this may cause diagnostic uncertainty. To determine the prevalence, imaging characteristics and evolution of splenic nodules found on MR imaging for iron overload evaluation. Retrospective review of all MR imaging examinations performed for iron overload assessment from 2005 to 2015 in a tertiary pediatric hospital. The presence of focal splenic nodules including number, size, signal characteristics and changes on follow-up MR imaging were recorded. Relevant patient clinical information including underlying hematological disease was also documented. A total of 318 patients had MR imaging for iron overload assessment. Of these, 25 (8%) had at least one incidental splenic nodule. Sickle cell disease was present in 22 patients (88%) and thalassemia in 3 (12%). On intermediate-weighted spin-echo images, the nodules had high signal intensity compared to the remainder of the spleen in 23 patients (92%) and low signal intensity in the remaining 2 (8%). In all patients (100%) the nodules showed progressive loss of signal intensity with increasing echo time values. Follow-up MR imaging was performed in 20 (80%) patients, which showed an increase in the size of the splenic nodules in 7 patients (35%) stability in 11 (55%) and a decrease in size in 2 (10%). It is not uncommon to find splenic nodules during MR evaluation of iron overload. In patients with sickle cell disease, most of these nodules are thought to represent preserved splenic tissue and appear hyperintense compared to the remainder of the spleen. They frequently remain stable on follow-up imaging, although about a third of them may show growth. Awareness of these nodules is important to avoid concern for potential malignancy and unnecessary investigations. (orig.)

  18. Albumin Overload and PINK1/Parkin Signaling-Related Mitophagy in Renal Tubular Epithelial Cells.

    Science.gov (United States)

    Tan, Jin; Xie, Qi; Song, Shuling; Miao, Yuyang; Zhang, Qiang

    2018-03-01

    BACKGROUND Albumin, as a major urinary protein component, is a risk factor for chronic kidney disease progression. Mitochondrial dysfunction is one of the main causes of albumin-induced proximal tubule cells injury. Mitophagy is considered as a pivotal protective mechanism for the elimination of dysfunctional mitochondria. The objective of this research was to determine whether albumin overload-induced mitochondrial dysfunction can activate PINK1/Parkin-mediated mitophagy in renal tubular epithelial cells (TECs). MATERIAL AND METHODS Immunofluorescence assay and Western blot assay were used to detect the effects of albumin overload on autophagy marker protein LC3. Transmission electron microscopy and Western blot assay were used to investigate the role of albumin in mitochondrial injury. Western blot assay and co-localization of acidic lysosomes and mitochondria assay were employed to detect the activation of mitophagy induced by albumin. Finally, we explored the role of PINK1/Parkin signaling in albumin-induced mitophagy by inhibiting mitophagy by knockdown of PARK2 (Parkin) level. RESULTS Immunofluorescence and Western blot results showed that the expression level of LC3-II increased, and the maximum increase point was observed after 8 h of albumin treatment. Transmission electron microscopy results demonstrated that albumin overload-induced mitochondrial injury and quantity of autophagosomes increased. Additionally, expression of PINK1 and cytosolic cytochrome C increased and mitochondria cytochrome C decreased in the albumin group. The co-localization of acidic lysosomes and mitochondria demonstrated that the number of albumin overload-induced mitophagy-positive dots increased. The transient transfection of PARK2 siRNA result showed knockdown of the expression level of PARK2 can inhibit mitophagy induced by albumin. CONCLUSIONS In conclusion, our study suggests that mitochondrial dysfunction activates the PINK1/Parkin signaling and mitophagy in renal tubular

  19. Iatrogenic Iron Overload in Dialysis Patients at the Beginning of the 21st Century.

    Science.gov (United States)

    Rostoker, Guy; Vaziri, Nosratola D; Fishbane, Steven

    2016-05-01

    Iron overload used to be considered rare in hemodialysis patients but its clinical frequency is now increasingly realized. The liver is the main site of iron storage and the liver iron concentration (LIC) is closely correlated with total iron stores in patients with secondary hemosideroses and genetic hemochromatosis. Magnetic resonance imaging is now the gold standard method for LIC estimation and monitoring in non-renal patients. Studies of LIC in hemodialysis patients by quantitative magnetic resonance imaging and magnetic susceptometry have demonstrated a strong relation between the risk of iron overload and the use of intravenous (IV) iron products prescribed at doses determined by the iron biomarker cutoffs contained in current anemia management guidelines. These findings have challenged the validity of both iron biomarker cutoffs and current clinical guidelines, especially with respect to recommended IV iron doses. Three long-term observational studies have recently suggested that excessive IV iron doses may be associated with an increased risk of cardiovascular events and death in hemodialysis patients. We postulate that iatrogenic iron overload in the era of erythropoiesis-stimulating agents may silently increase complications in dialysis patients without creating frank clinical signs and symptoms. High hepcidin-25 levels were recently linked to fatal and nonfatal cardiovascular events in dialysis patients. It is therefore tempting to postulate that the main pathophysiological pathway leading to these events may involve the pleiotropic master hormone hepcidin (synergized by fibroblast growth factor 23), which regulates iron metabolism. Oxidative stress as a result of IV iron infusions and iron overload, by releasing labile non-transferrin-bound iron, might represent a 'second hit' on the vascular bed. Finally, iron deposition in the myocardium of patients with severe iron overload might also play a role in the pathogenesis of sudden death in some patients.

  20. Incidental splenic nodules found on MR imaging done for assessment of iron overload in children

    Energy Technology Data Exchange (ETDEWEB)

    Ahyad, Rayan A.; Lam, Christopher Z.; Navarro, Oscar M. [University of Toronto, Department of Medical Imaging, Toronto, ON (Canada); The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto, ON (Canada); Shearkhani, Omid [The Hospital for Sick Children, Department of Diagnostic Imaging, Toronto, ON (Canada)

    2017-06-15

    MR imaging is used to assess iron overload in patients with hemoglobinopathies and in those who have undergone multiple blood transfusions. Sometimes splenic nodules are found incidentally on these examinations and this may cause diagnostic uncertainty. To determine the prevalence, imaging characteristics and evolution of splenic nodules found on MR imaging for iron overload evaluation. Retrospective review of all MR imaging examinations performed for iron overload assessment from 2005 to 2015 in a tertiary pediatric hospital. The presence of focal splenic nodules including number, size, signal characteristics and changes on follow-up MR imaging were recorded. Relevant patient clinical information including underlying hematological disease was also documented. A total of 318 patients had MR imaging for iron overload assessment. Of these, 25 (8%) had at least one incidental splenic nodule. Sickle cell disease was present in 22 patients (88%) and thalassemia in 3 (12%). On intermediate-weighted spin-echo images, the nodules had high signal intensity compared to the remainder of the spleen in 23 patients (92%) and low signal intensity in the remaining 2 (8%). In all patients (100%) the nodules showed progressive loss of signal intensity with increasing echo time values. Follow-up MR imaging was performed in 20 (80%) patients, which showed an increase in the size of the splenic nodules in 7 patients (35%) stability in 11 (55%) and a decrease in size in 2 (10%). It is not uncommon to find splenic nodules during MR evaluation of iron overload. In patients with sickle cell disease, most of these nodules are thought to represent preserved splenic tissue and appear hyperintense compared to the remainder of the spleen. They frequently remain stable on follow-up imaging, although about a third of them may show growth. Awareness of these nodules is important to avoid concern for potential malignancy and unnecessary investigations. (orig.)