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Sample records for chronic intermittent materno-fetal

  1. MATERNO-FETAL IMMUNOTOLERANCE: AN EVOLUTIONARY VIEW

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    Luana Paulesu

    2013-12-01

    Full Text Available Since Medawar (1953, much attention has been given to the immunological paradox of the survival and growth of the semi-allogeneic fetus in the maternal uterus. Numerous studies, mainly on the human placenta, have established fundamental mechanisms of this phenomenon; however, many aspects are still unclear and the complex process has yet to be completely defined. One of the accepted principles is that the secretion and action of mediators, i.e. cytokines, at the materno-fetal interface have a central role. Focusing on the cytokine Interleukin-1 (IL-1 the review highlights the importance of a physiological approach based on evolutionary studies in animals using similar or different reproductive strategies. Data on IL-1 in viviparity and oviparity, two reproductive strategies in which female reproductive tissues have to deal with paternal-derived antigens on sperm, fertilized eggs, and embryo, will be presented and discussed in the light of materno-fetal immuntolerance. Ovuliparity, a reproductive modality in which the eggs are released from the female reproductive tract and fertilization and embryonic development take place in the external environment will also be extensively reported as a negative control in the studies on materno-fetal immunotolerance. The evidence shown reveals that non-mammalian vertebrates with different reproductive strategies represent a good model to understand biological mechanisms allowing fetal acceptance and growth in the maternal tissues.

  2. Materno-Fetal Transmission of Human Immune Deficiency Virus

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    Axel Schäfer

    1997-01-01

    Full Text Available Mother-to-child transmission of human immune deficiency virus (HIV is a multifactorial event highly associated with advanced maternal HIV disease and obstetric incidents taking place during parturition. Thus, various approaches to prevention may be beneficial. Although the time and the route of materno-fetal HIV transmission are still not sufficiently clear, much speaks in favor of a late HIV transmission, most probably taking place during parturition or the phase before the delivery. The fetus is remarkably protected by the placenta and the intact fetal membranes against many viral infections during gestation. These conditions change at parturition and the chance for a transition of HIV-infected carrier cells or virus into the fetal compartment increases. Proinflammatory cytokines secreted at the materno-fetal interface accumulate in amniotic fluid and may chemoattract and stimulate potentially HIV-infected immunocytes. After rupture of membranes, maternal cells of the decidua are directly exposed to the amniotic fluid. Aside from the contamination of the fetal skin at vaginal delivery as a debatable route of infection, blood-to-blood contacts and the fetal swallowing of contaminated amniotic fluid may be the major path of fetal HIV infection. For the fetal prophylaxis of an intrauterine infection, the application of zidovudine is recommended. However, cesarian section before the onset of labor leads also to a diminution of the transmission rate. As the transmission seems to have both systemic and local causes, it makes sense to combine different intervention strategies. Whether a combination of zidovudine and elective cesarean section can lower the transmission risk further has to be evaluated.

  3. Vinculação da gestante e apego materno fetal

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    Eluisa Bordin Schmidt

    2009-08-01

    Full Text Available Este trabalho verificou as relações existentes entre o tipo de vinculação da gestante, sintomas de ansiedade, depressão e nível de apego materno fetal. Participaram 136 gestantes entre 18 e 42 anos de idade, do 6º ao 9º mês de gestação com escolaridade mínima de 5ª série. Foi realizado um estudo quantitativo, transversal, correlacional. Os instrumentos utilizados foram: Ficha de Dados Sociodemográficos, Escala de Vinculação do Adulto (EVA, Escala de Apego Materno Fetal (MFAS, Inventário de Depressão de Beck (BDI e Inventário de Ansiedade de Beck (BAI. A análise dos dados foi realizada por meio de estatística descritiva, teste exato de Fischer, simulações de Monte Carlo e Correlação de Pearson. Os resultados indicaram que existe associação significativa entre o tipo de vinculação da gestante e o apego materno fetal, e sintomas depressivos. As gestantes que apresentaram uma vinculação segura evidenciaram apego materno fetal alto e sintomas depressivos e ansiosos mínimos.

  4. Efeitos da ingestão de glicose sobre a circulação materno-fetal Materno-fetal hemodynamic repercussion of glucose ingestion

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    Rose Mary de Castro Ranciaro

    2006-12-01

    Full Text Available OBJETIVOS: analisar o efeito da glicose na hemodinâmica materno-fetal pela avaliação doplervelocimétrica da circulação materno-fetal e fetoplacentária. MÉTODOS: trata-se de estudo realizado por único observador, no qual foram incluídas 31 gestantes clinicamente sadias entre a 28ª e a 36ª semana. Os parâmetros foram avaliados imediatamente antes e 60 minutos após a ingestão de 50 g de glicose. Foram utilizados como critérios de inclusão a avaliação clínica e laboratorial normal, a presença de feto único, a idade gestacional entre a 28ª e a 36ª semana de gestação confirmada por exame de ultra-sonografia e/ou a data da última menstruação, a glicemia de jejum menor ou igual a 110 mg/dL e o teste de sobrecarga após 50 g de glicose menor de 140 mg/dL. Como critérios de exclusão, adotaram-se a presença de malformação ou alterações de desenvolvimento fetal, o trabalho de parto, os antecedentes familiares de diabetes, as patologias próprias ou intercorrentes à gestação e o uso de fumo, álcool ou outras drogas. Foram avaliados os vasos maternos da artéria carótida comum e artérias uterinas, os vasos placentários da artéria umbilical e os vasos fetais da artéria cerebral média e aorta abdominal. Foram analisados os seguintes parâmetros em cada vaso: índice de resistência, índice de pulsatilidade, velocidade sistólica máxima, velocidade diastólica final e tempo de aceleração. A freqüência cardíaca fetal foi avaliada pelo modo M da ultra-sonografia. Para análise estatística foi utilizado o teste t de Student quando a variável diferença de antes e depois da ingestão de glicose apresentou distribuição normal no teste de Kolmogorov-Smirnov. Quando a normalidade foi rejeitada, utilizamos o teste não-paramétrico de Wilcoxon, com o nível de significância sempre estabelecido de pPURPOSE: to analyze the effect of glucose in the materno-fetal hemodynamics through dopplervelocimetric assessment of

  5. Intermittent enhancement in chronic nodular calcified neurocysticercosis

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    Martin Oselkin, MD

    2015-01-01

    Full Text Available Neurocysticercosis (NCC is the most common cause of new onset seizures and epilepsy in the developing and tropical world. There has been a marked increase in domestic cases of diseases traditionally associated with developing countries, and now NCC should be high on a radiologist's differential diagnosis list for a patient with seizures. Radiologic findings of NCC correlate with the parasite's life cycle within the host. The calcified granulomas signify the final stage (nodular calcified as nonenhancing punctate calcifications on imaging and are traditionally known to remain without enhancement. Here we describe a unique case of intermittent enhancement of a cortical calcified nodule secondary to NCC that was followed for over 10 years. Radiologists must challenge the traditionally accepted progression of imaging findings and accept that calcified nodules of chronic NCC may intermittently enhance.

  6. Influência do Tabagismo no Sistema Vascular Materno-fetal: estudo com Dopplervelocimetria Effect of Cigarette Smoking on Maternal-fetal Blood Flow: Doppler Velocimetry Study

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    Gilberto Rodrigues Pinto

    2000-12-01

    Full Text Available Objetivo: avaliar a influência do tabagismo materno na dinâmica vascular materno-fetal, por meio da dopplervelocimetria obstétrica das artérias uterinas, umbilical e cerebral média. Métodos: estudo prospectivo em 42 gestantes saudáveis, sendo 20 fumantes e 22 não-fumantes. Foram realizadas ultra-sonografias para determinar o tempo de gestação e exame de dopplervelocimetria pulsátil das artérias uterinas, umbilical e cerebral média nas 24ª, 28ª, 32ª e 36ª semana para avaliar o fluxo vascular materno-fetal. As fumantes foram orientadas a não fumar por pelo menos 2 horas antes do exame. Resultados: o índice de resistência (IR médio das artérias uterinas D e E foi maior no grupo de fumantes na 36ª semana com média de 0,50 e desvio padrão de 0,034. O índice de pulsatilidade (IP da artéria umbilical foi maior no grupo de fumantes na 28ª semana [x (DP = 1,135 (0,182], p = 0,008; o IP da artéria cerebral média (ACM não se mostrou diferente entre os grupos, porém, a relação IP ACM/umbilical foi menor no grupo de fumantes, na 32ª semana [x (DP = 1,9 (0,291], p = 0,027 e na 36ª semana [x (DP = 1,850 (0,465], p = 0,014. Conclusões: os índices de dopplervelocimetria mostraram que no grupo de fumantes há aumento na resistência da circulação útero-placentária e feto-placentária, associado a concomitante diminuição na resistência da ACM, mimetizando uma tendência do tabagismo levar à hipóxia crônica do feto.Purpose: to evaluate the influence of cigarette smoking on uteroplacental, fetoplacental and fetal blood flow by obstetric Doppler velocimetry of the uterine, umbilical and middle cerebral arteries. Method: a prospective study with 42 healthy pregnant women, 20 of whom were smokers and 24 nonsmokers. Ultrasound was performed initially to determine the gestation time. The pregnant women next underwent pulsed and color Doppler velocimetry of the uterine, umbilical and middle cerebral arteries at the 24th, 28

  7. CXCL12/CXCR4 Expression in Trophoblasts Takes Part in Materno-fetal Immune Tolerance and Vascular Remodeling

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    YANG Yun; ZOU Li; LI Mei; ZHAO Yin

    2006-01-01

    In this study, we investigated the expression of CXCL 12 (SDF- 1)/CXCR4 in trophoblasts and the role they play in the gestation. Immunochemistry was used to detect the expression of CXCR4 and CXCL12 in human villi and placenta. Highly purified extra-villous trophoblasts (EVTs)ere detected for CXCR4 and CXCL 12 in vitro by immunocytochemistry. The chemotaxis of CXCL 12 was tested in transwell and the chemotactic activity was quantitatively examined. It was suggested that both CXCR4 and CXCL12 were expressed in trophoblasts and were decreased with the gestation time P<0.05). In a certain coverage, CXCL12 exhibited chemotactic activity which was positively correlated with its concentration [(r)=0.68, P<0.01], the maximum chemotactic index (CI) was 1.62±0.12. Our results suggest that interaction between CXCR4 and CXCL12 is involved in materno-fetal immunological tolerance in all three trimesters of gestation and contributes to the invasion of EVTs during pregnancy.

  8. Apego materno-fetal e a percepção materna acerca da capacidade interativa do bebê no primeiro mês = Maternal-fetal attachment and maternal perception about infant interactive skills in the first month = Apego materno-fetal y la percepción materna sobre la capacidad interactiva del bebé en el primer mes

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    Alvarenga, Patrícia

    2015-01-01

    Full Text Available A percepção da mãe acerca das capacidades interativas do recém-nascido tem sido apontada como um fator crucial para o estabelecimento de padrões interativos de qualidade entre a díade mãe-filho. O objetivo deste estudo foi examinar as relações entre o apego materno-fetal e a percepção da mãe acerca das capacidades interativas do bebê. Participaram do estudo 64 mães de bebês do sexo masculino, que responderam a Escala de Apego Materno-fetal, no terceiro trimestre da gestação, e uma entrevista sobre a experiência da maternidade, no primeiro mês do bebê. Houve uma correlação positiva entre o apego materno-fetal e a percepção geral das capacidades interativas do bebê (r=0,23; p<0,05. A análise de regressão confirmou que a escolaridade materna e o apego materno-fetal explicaram 12% da variância na percepção da mãe acerca das capacidades interativas dos bebês. Discute-se a relevância da relação da mãe com o feto durante a gestação para a interação mãe-bebê no período pós-natal

  9. [Intermittent thrombolytic treatment. Results during severe, chronic arterial diseases].

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    Fiessinger, J N; Aiach, M; Lagneau, P; Cormier, J M; Housset, E

    1975-04-20

    38 patients with severe chronic arteritis of the lower limbs were treated with streptokinase intermittently. All had been refused for surgical operation. One patient died, 4 others had early interruption of treatment. Eleven of the 38 patients had efficient thrombolysis confirmed by arteriography. The facts confirm the possibility of thrombolysis during chronic arterial disease. The fact that the aggravation was recent was favourable factor in prognosis. The eleven patients improved, had severe aggravation of symptomes for less than 2 months. Thus thrombolytic treatment has a place of choice in the treatment of severe arterial disease where surgery is impossible, or dangerous, owing to the uncertain state of the vascular bed below the lesion. Efficacious, it permits reconstructive surgery in cases where it had been at first refused. The use of intermittent treatment, apart from advantages of confort and cost, seems to increase the efficacy of treatment. PMID:176733

  10. [Intermittent thrombolytic treatment. Results during severe, chronic arterial diseases].

    Science.gov (United States)

    Fiessinger, J N; Aiach, M; Lagneau, P; Cormier, J M; Housset, E

    1975-04-20

    38 patients with severe chronic arteritis of the lower limbs were treated with streptokinase intermittently. All had been refused for surgical operation. One patient died, 4 others had early interruption of treatment. Eleven of the 38 patients had efficient thrombolysis confirmed by arteriography. The facts confirm the possibility of thrombolysis during chronic arterial disease. The fact that the aggravation was recent was favourable factor in prognosis. The eleven patients improved, had severe aggravation of symptomes for less than 2 months. Thus thrombolytic treatment has a place of choice in the treatment of severe arterial disease where surgery is impossible, or dangerous, owing to the uncertain state of the vascular bed below the lesion. Efficacious, it permits reconstructive surgery in cases where it had been at first refused. The use of intermittent treatment, apart from advantages of confort and cost, seems to increase the efficacy of treatment.

  11. The efficacy of antihypertensive drugs in chronic intermittent hypoxia conditions

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    Lucilia Neves Diogo; Emília Carreira Monteiro

    2014-01-01

    Sleep apnea/hypopnea disorders include centrally originated diseases and obstructive sleep apnea (OSA). This last condition is renowned as a frequent secondary cause of hypertension (HT). The mechanisms involved in the pathogenesis of HT can be summarized in relation to two main pathways: sympathetic nervous system stimulation mediated mainly by activation of carotid body (CB) chemoreflexes and/or asphyxia, and, by no means the least important, the systemic effects of chronic intermittent hyp...

  12. Respiratory plasticity in the behaving rat following chronic intermittent hypoxia.

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    Edge, Deirdre; Skelly, J Richard; Bradford, Aidan; O'Halloran, Ken D

    2010-01-01

    Chronic intermittent hypoxia (CIH), a feature of obstructive sleep apnoea (OSA) has been shown to have myriad effects on the respiratory control system. The effects on breathing are of great clinical significance for the sleep apnoea patient. We sought to determine the effect of CIH on normoxic ventilation. Both male and female adult Wistar rats were studied due to the evident sex difference in the prevalence of OSA. A role for oxidative stress in respiratory modifications was also explored. Adult male (n = 30) and female (n = 16) rats were exposed to alternating periods of N(2) and O(2) for 90 s each, bringing the ambient oxygen concentration to 5% at nadir (CIH) group. Sham groups were subject to cycles of air/air under identical experimental conditions. A subset of male rats (8 controls, 8 CIH) had free access to water containing 1 mM Tempol (SOD-mimetic) at all times. Treatments were carried out for 8 hours a day for 9 days. Following treatment, normoxic ventilation was assessed by whole body plethysmography in sleeping animals. Baseline normoxic ventilation was increased in both male and female treated rats but this did not achieve statistical significance. However, ventilatory drive (V(T)/Ti) was significantly increased in male rats. Chronic treatment with Tempol abolished this effect. Conversely, CIH had no significant effect on VT/Ti in female rats. Our results indicate subtle effects of intermittent hypoxia on breathing in conscious behaving rats. We speculate the increased ventilatory drive following CIH represents a form a neural plasticity - a ROS dependent phenomenon - with sexual dimorphism. PMID:20217363

  13. The efficacy of antihypertensive drugs in chronic intermittent hypoxia conditions.

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    Diogo, Lucilia N; Monteiro, Emília C

    2014-01-01

    Sleep apnea/hypopnea disorders include centrally originated diseases and obstructive sleep apnea (OSA). This last condition is renowned as a frequent secondary cause of hypertension (HT). The mechanisms involved in the pathogenesis of HT can be summarized in relation to two main pathways: sympathetic nervous system stimulation mediated mainly by activation of carotid body (CB) chemoreflexes and/or asphyxia, and, by no means the least important, the systemic effects of chronic intermittent hypoxia (CIH). The use of animal models has revealed that CIH is the critical stimulus underlying sympathetic activity and hypertension, and that this effect requires the presence of functional arterial chemoreceptors, which are hyperactive in CIH. These models of CIH mimic the HT observed in humans and allow the study of CIH independently without the mechanical obstruction component. The effect of continuous positive airway pressure (CPAP), the gold standard treatment for OSA patients, to reduce blood pressure seems to be modest and concomitant antihypertensive therapy is still required. We focus this review on the efficacy of pharmacological interventions to revert HT associated with CIH conditions in both animal models and humans. First, we explore the experimental animal models, developed to mimic HT related to CIH, which have been used to investigate the effect of antihypertensive drugs (AHDs). Second, we review what is known about drug efficacy to reverse HT induced by CIH in animals. Moreover, findings in humans with OSA are cited to demonstrate the lack of strong evidence for the establishment of a first-line antihypertensive regimen for these patients. Indeed, specific therapeutic guidelines for the pharmacological treatment of HT in these patients are still lacking. Finally, we discuss the future perspectives concerning the non-pharmacological and pharmacological management of this particular type of HT. PMID:25295010

  14. The efficacy of antihypertensive drugs in chronic intermittent hypoxia conditions

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    Lucilia Neves Diogo

    2014-09-01

    Full Text Available Sleep apnea/hypopnea disorders include centrally originated diseases and obstructive sleep apnea (OSA. This last condition is renowned as a frequent secondary cause of hypertension (HT. The mechanisms involved in the pathogenesis of HT can be summarized in relation to two main pathways: sympathetic nervous system stimulation mediated mainly by activation of carotid body (CB chemoreflexes and/or asphyxia, and, by no means the least important, the systemic effects of chronic intermittent hypoxia (CIH. The use of animal models has revealed that CIH is the critical stimulus underlying sympathetic activity and hypertension, and that this effect requires the presence of functional arterial chemoreceptors, which are hyperactive in CIH. These models of CIH mimic the HT observed in humans and allow the study of CIH independently without the mechanical obstruction component. The effect of continuous positive airway pressure, the gold standard treatment for OSA patients, to reduce blood pressure seems to be modest and concomitant antihypertensive therapy is still required. We focus this review on the efficacy of pharmacological interventions to revert HT associated with CIH conditions in both animal models and humans. First, we explore the experimental animal models, developed to mimic HT related to CIH, which have been used to investigate the effect of antihypertensive drugs (AHDs. Second, we review what is known about drug efficacy to reverse HT induced by CIH in animals. Moreover, findings in humans with OSA are cited to demonstrate the lack of strong evidence for the establishment of a first-line antihypertensive regimen for these patients. Indeed, specific therapeutic guidelines for the pharmacological treatment of HT in these patients are still lacking. Finally, we discuss the future perspectives concerning the non-pharmacological and pharmacological management of this particular type of HT.

  15. Evolução e prognóstico materno-fetal da cirurgia cardíaca durante a gravidez Evolución y pronóstico materno-fetal de la cirugía cardiaca durante el embarazo Maternal-fetal outcome and prognosis of cardiac surgery during pregnancy

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    Walkiria Samuel Ávila

    2009-07-01

    Full Text Available FUNDAMENTO: A cirurgia cardíaca favorece o prognóstico materno em casos refratários à terapêutica clínica, contudo associa-se a riscos ao concepto quando realizada durante a gravidez. OBJETIVO: Analisar a evolução e o prognóstico materno-fetal de gestantes submetidas à cirurgia cardíaca no ciclo gravídico-puerperal. MÉTODOS: Estudou-se a evolução de 41 gestações de mulheres que tiveram indicação de cirurgia cardíaca no ciclo gravídico puerperal. A cardiotocografia fetal foi mantida durante o procedimento nas pacientes com idade gestacional acima de 20 semanas. RESULTADOS: A média da idade materna foi de 27,8 ± 7,6 anos, houve predomínio da valvopatia reumática (87,8%, e 15 dessas (41,6% foram submetidas à reoperação, devido à disfunção de prótese valvar. A média do tempo de circulação extracorpórea foi de 87,4 ± 43,6 min, e a hipotermia foi utilizada em 27 casos (67,5%. Treze mães (31,7% não apresentaram intercorrências e tiveram seus recém-nascidos vivos e saudáveis. A evolução pós-operatória das demais 28 gestações (68,3% mostrou: 17 complicações maternas (41,5%; três óbitos (7,3%; 12 perdas fetais (29,2% e quatro casos de malformação neurológica (10%, dois dos quais evoluíram para óbito tardio. Houve uma perda de seguimento após a cirurgia. Nove pacientes (21,9% foram operadas em caráter de emergência, situação que influenciou (p FUNDAMENTO: La cirugía cardiaca favorece el pronóstico materno en casos refractarios a la terapéutica clínica, sin embargo está asociada a riesgos cuando realizada durante el embarazo. OBJETIVO: Analizar la evolución y el pronóstico materno-fetal de gestantes sometidas a la cirugía cardiaca en el ciclo grávido puerperal. MÉTODOS: Se estudió la evolución de 41 gestaciones de mujeres que tuvieron indicación de cirugía cardiaca en el ciclo grávido puerperal. La cardiotocografía fetal se mantuvo durante el procedimiento en las pacientes con

  16. The impact of chronic intermittent hypoxia on hematopoiesis and the bone marrow microenvironment

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    Alvarez-Martins, Inês; Remédio, Leonor; Matias, Inês; Diogo, Lucília N; Monteiro, Emília C; Dias, Sérgio

    2016-01-01

    Obstructive sleep apnea (OSA) is a highly prevalent sleep-related breathing disorder which is associated with patient morbidity and an elevated risk of developing hypertension and cardiovascular diseases. There is ample evidence for the involvement of bone marrow (BM) cells in the pathophysiology of cardiovascular diseases but a connection between OSA and modulation of the BM microenvironment had not been established. Here, we studied how chronic intermittent hypoxia (CIH) affected hematopoie...

  17. CHRONIC INTERMITTENT HYPOXIA AFFECTS INTEGRATION OF SENSORY INPUT BY NEURONS IN THE NUCLEUS TRACTUS SOLITARII

    OpenAIRE

    Kline, David D.

    2010-01-01

    The autonomic nervous and respiratory systems, as well as their coupling, adapt over a wide range of conditions. Chronic intermittent hypoxia (CIH) is a model for recurrent apneas and induces alterations in breathing and increases in sympathetic nerve activity which may ultimately result in hypertension if left untreated. These alterations are believed to be due to increases in the carotid body chemoreflex pathway. Here we present evidence that the nucleus tractus solitarii (nTS), the central...

  18. Chronic intermittent hypoxia and obstructive sleep apnea: an experimental and clinical approach

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    Sforza E

    2016-04-01

    Full Text Available Emilia Sforza, Fréderic Roche Service de Physiologie Clinique et de l'Exercice, Pole NOL, CHU, EA SNA-EPIS 4607, Faculté de Médecine J. Lisfranc, UJM Saint-Etienne, Université de Lyon, Saint-Etienne, France Abstract: Obstructive sleep apnea (OSA is a prevalent sleep disorder considered as an independent risk factor for cardiovascular consequences, such as systemic arterial hypertension, ischemic heart disease, cardiac arrhythmias, metabolic disorders, and cognitive dysfunction. The pathogenesis of OSA-related consequence is assumed to be chronic intermittent hypoxia (IH inducing alterations at the molecular level, oxidative stress, persistent systemic inflammation, oxygen sensor activation, and increase of sympathetic activity. Overall, these mechanisms have an effect on vessel permeability and are considered to be important factors for explaining vascular, metabolic, and cognitive OSA-related consequences. The present review attempts to examine together the research paradigms and clinical studies on the effect of acute and chronic IH and the potential link with OSA. We firstly describe the literature data on the mechanisms activated by acute and chronic IH at the experimental level, which are very helpful and beneficial to explaining OSA consequences. Then, we describe in detail the effect of IH in patients with OSA that we can consider "the human model" of chronic IH. In this way, we can better understand the specific pathophysiological mechanisms proposed to explain the consequences of IH in OSA. Keywords: hypoxia, intermittent hypoxia, experimental studies, obstructive sleep apnea

  19. Sustained acclimatization in Chilean mine workers subjected to chronic intermittent hypoxia.

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    Farias, Jorge G; Osorio, Jorge; Soto, Gustavo; Brito, Julio; Siques, Patricia; Reyes, Juan G

    2006-01-01

    Farias, Jorge G., Jorge Osorio, Gustavo Soto, Julio Brito, Patricia Siques, and Juan G. Reyes. Sustained acclimatization in Chilean mine workers subjected to chronic intermittent hypoxia. High Alt. Med. Biol. 7:302-306, 2006--We wanted to know if sea-level mine workers exposed previously to chronic intermittent hypoxia reached a steady acclimatization at 36 months under hypobaric hypoxia. An intermittently exposed group of mine workers (IE, n = 25) were subjected to submaximal exercise (100 W) at 4500 m. Their systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and hemoglobin oxygen saturation (HbSatO(2)) were monitored. Two comparison groups of unacclimatized sea-level workers (n = 17) were studied. A nonexposed group (NE) performed 5 min of submaximal exercise at sea level. Some kind of exercise was performed both by an acutely exposed group (AE) and IE group at 4500 m. No statistical differences were found for HR, SBP, and DBP (p > 0.05) during exercise between IE and AE groups. Resting HbSatO(2) of IE (87 +/- 6%) was lower than NE (97 +/- 3%) (p < 0.05), but was higher than AE (82 +/- 4%) (p < 0.05). In the exercise condition, HbSatO(2) of IE (85 +/- 5%) was lower than NE (95 +/- 3%) (p < 0.05), but was higher than AE (76 +/- 2%) (p < 0.05). These responses were maintained through the 6 months of the study period. Thus, mine workers subjected to intermittent hypobaric condition for 3 years showed a good degree of acclimatization that was maintained through time. PMID:17173515

  20. Chronic intermittent psychological stress promotes macrophage reverse cholesterol transport by impairing bile acid absorption in mice.

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    Silvennoinen, Reija; Quesada, Helena; Kareinen, Ilona; Julve, Josep; Kaipiainen, Leena; Gylling, Helena; Blanco-Vaca, Francisco; Escola-Gil, Joan Carles; Kovanen, Petri T; Lee-Rueckert, Miriam

    2015-05-11

    Psychological stress is a risk factor for atherosclerosis, yet the pathophysiological mechanisms involved remain elusive. The transfer of cholesterol from macrophage foam cells to liver and feces (the macrophage-specific reverse cholesterol transport, m-RCT) is an important antiatherogenic pathway. Because exposure of mice to physical restraint, a model of psychological stress, increases serum levels of corticosterone, and as bile acid homeostasis is disrupted in glucocorticoid-treated animals, we investigated if chronic intermittent restraint stress would modify m-RCT by altering the enterohepatic circulation of bile acids. C57Bl/6J mice exposed to intermittent stress for 5 days exhibited increased transit through the large intestine and enhanced fecal bile acid excretion. Of the transcription factors and transporters that regulate bile acid homeostasis, the mRNA expression levels of the hepatic farnesoid X receptor (FXR), the bile salt export pump (BSEP), and the intestinal fibroblast growth factor 15 (FGF15) were reduced, whereas those of the ileal apical sodium-dependent bile acid transporter (ASBT), responsible for active bile acid absorption, remained unchanged. Neither did the hepatic expression of cholesterol 7α-hydroxylase (CYP7A1), the key enzyme regulating bile acid synthesis, change in the stressed mice. Evaluation of the functionality of the m-RCT pathway revealed increased fecal excretion of bile acids that had been synthesized from macrophage-derived cholesterol. Overall, our study reveals that chronic intermittent stress in mice accelerates m-RCT specifically by increasing fecal excretion of bile acids. This novel mechanism of m-RCT induction could have antiatherogenic potential under conditions of chronic stress. PMID:25969465

  1. Diaphragm Muscle Remodeling in a Rat Model of Chronic Intermittent Hypoxia

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    Shortt, Christine M.; Fredsted, Anne; Bradford, Aidan; O’Halloran, Ken D.

    2013-01-01

    Respiratory muscle remodeling occurs in human sleep apnea—a common respiratory disorder characterized by chronic intermittent hypoxia (CIH) due to recurrent apnea during sleep. We sought to determine if CIH causes remodeling in rat sternohyoid (upper airway dilator) and diaphragm muscles. Adult male Wistar rats were exposed to CIH (n=8), consisting of 90 sec of hypoxia (5% at the nadir; SaO2 ~80%)/90 sec of normoxia, 8 hr per day, for 7 consecutive days. Sham animals (n=8) were exposed to alt...

  2. Intermittent targeted therapies and stochastic evolution in patients affected by chronic myeloid leukemia

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    Pizzolato, N.; Persano Adorno, D.; Valenti, D.; Spagnolo, B.

    2016-05-01

    Front line therapy for the treatment of patients affected by chronic myeloid leukemia (CML) is based on the administration of tyrosine kinase inhibitors, namely imatinib or, more recently, axitinib. Although imatinib is highly effective and represents an example of a successful molecular targeted therapy, the appearance of resistance is observed in a proportion of patients, especially those in advanced stages. In this work, we investigate the appearance of resistance in patients affected by CML, by modeling the evolutionary dynamics of cancerous cell populations in a simulated patient treated by an intermittent targeted therapy. We simulate, with the Monte Carlo method, the stochastic evolution of initially healthy cells to leukemic clones, due to genetic mutations and changes in their reproductive behavior. We first present the model and its validation with experimental data by considering a continuous therapy. Then, we investigate how fluctuations in the number of leukemic cells affect patient response to the therapy when the drug is administered with an intermittent time scheduling. Here we show that an intermittent therapy (IT) represents a valid choice in patients with high risk of toxicity, despite an associated delay to the complete restoration of healthy cells. Moreover, a suitably tuned IT can reduce the probability of developing resistance.

  3. Behavioural and neurochemical comparison of chronic intermittent cathinone, mephedrone and MDMA administration to the rat.

    Science.gov (United States)

    Shortall, Sinead E; Macerola, Alice E; Swaby, Rabbi T R; Jayson, Rebecca; Korsah, Chantal; Pillidge, Katharine E; Wigmore, Peter M; Ebling, Francis J P; Richard Green, A; Fone, Kevin C F; King, Madeleine V

    2013-09-01

    The synthetic cathinone derivative, mephedrone, is a controlled substance across Europe. Its effects have been compared by users to 3,4-methylenedioxymethamphetamine (MDMA), but little data exist on its pharmacological properties. This study compared the behavioural and neurochemical effects of mephedrone with cathinone and MDMA in rats. Young-adult male Lister hooded rats received i.p. cathinone (1 or 4 mg/kg), mephedrone (1, 4 or 10mg/kg) or MDMA (10mg/kg) on two consecutive days weekly for 3 weeks or as a single acute injection (for neurochemical analysis). Locomotor activity (LMA), novel object discrimination (NOD), conditioned emotional response (CER) and prepulse inhibition of the acoustic startle response (PPI) were measured following intermittent drug administration. Dopamine, 5-hydroxytryptamine (5-HT) and their major metabolites were measured in striatum, frontal cortex and hippocampus by high performance liquid chromatography 7 days after intermittent dosing and 2h after acute injection. Cathinone (1, 4 mg/kg), mephedrone (10mg/kg) and MDMA (10mg/kg) induced hyperactivity following the first and sixth injections and sensitization to cathinone and mephedrone occurred with chronic dosing. All drugs impaired NOD and mephedrone (10mg/kg) reduced freezing in response to contextual re-exposure during the CER retention trial. Acute MDMA reduced hippocampal 5-HT and 5-HIAA but the only significant effect on dopamine, 5-HT and their metabolites following chronic dosing was altered hippocampal 3,4-dihydroxyphenylacetic acid (DOPAC), following mephedrone (4, 10mg/kg) and MDMA. At the doses examined, mephedrone, cathinone, and MDMA induced similar effects on behaviour and failed to induce neurotoxic damage when administered intermittently over 3 weeks.

  4. Neuroprotective Role of Intermittent Hypobaric Hypoxia in Unpredictable Chronic Mild Stress Induced Depression in Rats.

    Directory of Open Access Journals (Sweden)

    Neetu Kushwah

    Full Text Available Hypoxic exposure results in several pathophysiological conditions associated with nervous system, these include acute and chronic mountain sickness, loss of memory, and high altitude cerebral edema. Previous reports have also suggested the role of hypoxia in pathogenesis of depression and related psychological conditions. On the other hand, sub lethal intermittent hypoxic exposure induces protection against future lethal hypoxia and may have beneficial effect. Therefore, the present study was designed to explore the neuroprotective role of intermittent hypobaric hypoxia (IHH in Unpredictable Chronic Mild Stress (UCMS induced depression like behaviour in rats. The IHH refers to the periodic exposures to hypoxic conditions interrupted by the normoxic or lesser hypoxic conditions. The current study examines the effect of IHH against UCMS induced depression, using elevated plus maze (EPM, open field test (OFT, force swim test (FST, as behavioural paradigm and related histological and molecular approaches. The data indicated the UCMS induced depression like behaviour as evident from decreased exploration activity in OFT with increased anxiety levels in EPM, and increased immobility time in the FST; whereas on providing the IHH (5000m altitude, 4hrs/day for two weeks these behavioural changes were ameliorated. The morphological and molecular studies also validated the neuroprotective effect of IHH against UCMS induced neuronal loss and decreased neurogenesis. Here, we also explored the role of Brain-Derived Neurotrophic Factor (BDNF in anticipatory action of IHH against detrimental effect of UCMS as upon blocking of BDNF-TrkB signalling the beneficial effect of IHH was nullified. Taken together, the findings of our study demonstrate that the intermittent hypoxia has a therapeutic potential similar to an antidepressant in animal model of depression and could be developed as a preventive therapeutic option against this pathophysiological state.

  5. Neuroprotective Role of Intermittent Hypobaric Hypoxia in Unpredictable Chronic Mild Stress Induced Depression in Rats.

    Science.gov (United States)

    Kushwah, Neetu; Jain, Vishal; Deep, Satayanarayan; Prasad, Dipti; Singh, Shashi Bala; Khan, Nilofar

    2016-01-01

    Hypoxic exposure results in several pathophysiological conditions associated with nervous system, these include acute and chronic mountain sickness, loss of memory, and high altitude cerebral edema. Previous reports have also suggested the role of hypoxia in pathogenesis of depression and related psychological conditions. On the other hand, sub lethal intermittent hypoxic exposure induces protection against future lethal hypoxia and may have beneficial effect. Therefore, the present study was designed to explore the neuroprotective role of intermittent hypobaric hypoxia (IHH) in Unpredictable Chronic Mild Stress (UCMS) induced depression like behaviour in rats. The IHH refers to the periodic exposures to hypoxic conditions interrupted by the normoxic or lesser hypoxic conditions. The current study examines the effect of IHH against UCMS induced depression, using elevated plus maze (EPM), open field test (OFT), force swim test (FST), as behavioural paradigm and related histological and molecular approaches. The data indicated the UCMS induced depression like behaviour as evident from decreased exploration activity in OFT with increased anxiety levels in EPM, and increased immobility time in the FST; whereas on providing the IHH (5000m altitude, 4hrs/day for two weeks) these behavioural changes were ameliorated. The morphological and molecular studies also validated the neuroprotective effect of IHH against UCMS induced neuronal loss and decreased neurogenesis. Here, we also explored the role of Brain-Derived Neurotrophic Factor (BDNF) in anticipatory action of IHH against detrimental effect of UCMS as upon blocking of BDNF-TrkB signalling the beneficial effect of IHH was nullified. Taken together, the findings of our study demonstrate that the intermittent hypoxia has a therapeutic potential similar to an antidepressant in animal model of depression and could be developed as a preventive therapeutic option against this pathophysiological state. PMID:26901349

  6. High prevalence of and potential mechanisms for chronic kidney disease in patients with acute intermittent porphyria.

    Science.gov (United States)

    Pallet, Nicolas; Mami, Iadh; Schmitt, Caroline; Karim, Zoubida; François, Arnaud; Rabant, Marion; Nochy, Dominique; Gouya, Laurent; Deybach, Jean-Charles; Xu-Dubois, Yichum; Thervet, Eric; Puy, Hervé; Karras, Alexandre

    2015-08-01

    Acute intermittent porphyria (AIP) is a genetic disorder of the synthesis of heme caused by a deficiency in hydroxymethylbilane synthase (HMBS), leading to the overproduction of the porphyrin precursors δ-aminolevulinic acid and porphobilinogen. The aim of this study is to describe the clinical and biological characteristics, the renal pathology, and the cellular mechanisms of chronic kidney disease associated with AIP. A total of 415 patients with HMBS deficiency followed up in the French Porphyria Center were enrolled in 2003 in a population-based study. A follow-up study was conducted in 2013, assessing patients for clinical, biological, and histological parameters. In vitro models were used to determine whether porphyrin precursors promote tubular and endothelial cytotoxicity. Chronic kidney disease occurred in up to 59% of the symptomatic AIP patients, with a decline in the glomerular filtration rate of ~1 ml/min per 1.73 m(2) annually. Proteinuria was absent in the vast majority of the cases. The renal pathology was a chronic tubulointerstitial nephropathy, associated with a fibrous intimal hyperplasia and focal cortical atrophy. Our experimental data provide evidence that porphyrin precursors promote endoplasmic reticulum stress, apoptosis, and epithelial phenotypic changes in proximal tubular cells. In conclusion, the diagnosis of chronic kidney disease associated with AIP should be considered in cases of chronic tubulointerstitial nephropathy and/or focal cortical atrophy with severe proliferative arteriosclerosis.

  7. Superficially, longer, intermittent ozone theraphy in the treatment of the chronic, infected wounds.

    Science.gov (United States)

    Białoszewski, Dariusz; Kowalewski, Michał

    2003-10-30

    Background. Ozone therapy - i.e. the treatment of patients by a mixture of oxygen and ozone - has been used for many years as a method ancillary to basic treatment, especially in those cases in which traditional treatment methods do not give satisfactory results, e.g. skin loss in non-healing wounds, ulcers, pressure sores, fistulae, etc. Material and methods. In the Department of Phisiotherapy of the Medical Faculty and the Department of the Orthopedics and Traumatology of the Locomotor System at the Medical University of Warsaw in the period from January 2001 until November 2002, 23 patients with heavy,chronic, antibiotic resistants septic complications after trauma, surgical procedures and secundary skin infetions were treated with ozone. The ozone therapy was administered using an authorial technique of superficially, longer, intermittent ozone application. Results. In the wounds of the all experienced patients the inhibition of septic processes and wound healing was much faster than normal. Conclusions. Our data confirm the advantages wich result from the technique of superficially, longer, intermittent ozone theraphy in combined treatment for septic complications in the soft tissue, especially in the locomotor system. These technique makes posttraumatic infections and promotes quicker healing of post-surgical and post-traumal complications - chronic septic infections. This method also lowers the cost of antibiotic therapy and is sometimes the only available auxiliary technique to support surgical procedures.

  8. Superficially, longer, intermittent ozone theraphy in the treatment of the chronic, infected wounds.

    Science.gov (United States)

    Białoszewski, Dariusz; Kowalewski, Michał

    2003-10-30

    Background. Ozone therapy - i.e. the treatment of patients by a mixture of oxygen and ozone - has been used for many years as a method ancillary to basic treatment, especially in those cases in which traditional treatment methods do not give satisfactory results, e.g. skin loss in non-healing wounds, ulcers, pressure sores, fistulae, etc. Material and methods. In the Department of Phisiotherapy of the Medical Faculty and the Department of the Orthopedics and Traumatology of the Locomotor System at the Medical University of Warsaw in the period from January 2001 until November 2002, 23 patients with heavy,chronic, antibiotic resistants septic complications after trauma, surgical procedures and secundary skin infetions were treated with ozone. The ozone therapy was administered using an authorial technique of superficially, longer, intermittent ozone application. Results. In the wounds of the all experienced patients the inhibition of septic processes and wound healing was much faster than normal. Conclusions. Our data confirm the advantages wich result from the technique of superficially, longer, intermittent ozone theraphy in combined treatment for septic complications in the soft tissue, especially in the locomotor system. These technique makes posttraumatic infections and promotes quicker healing of post-surgical and post-traumal complications - chronic septic infections. This method also lowers the cost of antibiotic therapy and is sometimes the only available auxiliary technique to support surgical procedures. PMID:17679848

  9. Chronic intermittent ethanol induced axon and myelin degeneration is attenuated by calpain inhibition.

    Science.gov (United States)

    Samantaray, Supriti; Knaryan, Varduhi H; Patel, Kaushal S; Mulholland, Patrick J; Becker, Howard C; Banik, Naren L

    2015-10-01

    Chronic alcohol consumption causes multifaceted damage to the central nervous system (CNS), underlying mechanisms of which are gradually being unraveled. In our previous studies, activation of calpain, a calcium-activated neutral protease has been found to cause detrimental alterations in spinal motor neurons following ethanol (EtOH) exposure in vitro. However, it is not known whether calpain plays a pivotal role in chronic EtOH exposure-induced structural damage to CNS in vivo. To test the possible involvement of calpain in EtOH-associated neurodegenerative mechanisms the present investigation was conducted in a well-established mouse model of alcohol dependence - chronic intermittent EtOH (CIE) exposure and withdrawal. Our studies indicated significant loss of axonal proteins (neurofilament light and heavy, 50-60%), myelin proteins (myelin basic protein, 20-40% proteolipid protein, 25%) and enzyme (2', 3'-cyclic-nucleotide 3'-phosphodiesterase, 21-55%) following CIE in multiple regions of brain including hippocampus, corpus callosum, cerebellum, and importantly in spinal cord. These CIE-induced deleterious effects escalated after withdrawal in each CNS region tested. Increased expression and activity of calpain along with enhanced ratio of active calpain to calpastatin (sole endogenous inhibitor) was observed after withdrawal compared to EtOH exposure. Pharmacological inhibition of calpain with calpeptin (25 μg/kg) prior to each EtOH vapor inhalation significantly attenuated damage to axons and myelin as demonstrated by immuno-profiles of axonal and myelin proteins, and Luxol Fast Blue staining. Calpain inhibition significantly protected the ultrastructural integrity of axons and myelin compared to control as confirmed by electron microscopy. Together, these findings confirm CIE exposure and withdrawal induced structural alterations in axons and myelin, predominantly after withdrawal and corroborate calpain inhibition as a potential protective strategy against

  10. Chronic intermittent hypoxia alters ventilatory and metabolic responses to acute hypoxia in rats.

    Science.gov (United States)

    Morgan, Barbara J; Adrian, Russell; Wang, Zun-Yi; Bates, Melissa L; Dopp, John M

    2016-05-15

    We determined the effects of chronic exposure to intermittent hypoxia (CIH) on chemoreflex control of ventilation in conscious animals. Adult male Sprague-Dawley rats were exposed to CIH [nadir oxygen saturation (SpO2), 75%; 15 events/h; 10 h/day] or normoxia (NORM) for 21 days. We assessed the following responses to acute, graded hypoxia before and after exposures: ventilation (V̇e, via barometric plethysmography), V̇o2 and V̇co2 (analysis of expired air), heart rate (HR), and SpO2 (pulse oximetry via neck collar). We quantified hypoxia-induced chemoreceptor sensitivity by calculating the stimulus-response relationship between SpO2 and the ventilatory equivalent for V̇co2 (linear regression). An additional aim was to determine whether CIH causes proliferation of carotid body glomus cells (using bromodeoxyuridine). CIH exposure increased the slope of the V̇e/V̇co2/SpO2 relationship and caused hyperventilation in normoxia. Bromodeoxyuridine staining was comparable in CIH and NORM. Thus our CIH paradigm augmented hypoxic chemosensitivity without causing glomus cell proliferation. PMID:26917692

  11. Endoplasmic reticulum stress plays critical role in brain damage after chronic intermittent hypoxia in growing rats.

    Science.gov (United States)

    Cai, Xiao-Hong; Li, Xiu-Cui; Jin, Sheng-Wei; Liang, Dong-Shi; Wen, Zheng-Wang; Cao, Hong-Chao; Mei, Hong-Fang; Wu, Ying; Lin, Zhong-Dong; Wang, Liang-Xing

    2014-07-01

    Obstructive sleep apnea hypopnea syndrome (OSAHS) in children is associated with multiple system morbidities. Cognitive dysfunction as a result of central nervous system complication has been reported in children with OSAHS. However, the underlying mechanisms are poorly understood. Endoplasmic reticulum stress (ERS)-related apoptosis plays an important role in various diseases of the central nervous system, but very little is known about the role of ERS in mediating pathophysiological reactions to cognitive dysfunction in OSAHS. Chronic intermittent hypoxia (CIH) exposures, modeling OSAHS, across 2 and 4weeks in growing rats made more reference memory errors, working memory errors and total memory errors in the 8-Arm radial maze task, increased significantly TUNEL positive cells, upregulated the unfolded protein response in the hippocampus and prefrontal cortex as evidenced by increased phosphorylation of PKR-like endoplasmic reticulum kinase, inositol-requiring enzyme l and some downstream products. A selective inhibitor of eukaryotic initiation factor-2a dephosphorylation, salubrinal, prevented C/EBP-homologous protein activation in the hippocampus and prefrontal cortex throughout hypoxia/reoxygenation exposure. Our findings suggest that ERS mediated cell apoptosis may be one of the underlying mechanisms of cognitive dysfunction in OSAHS children. Further, a specific ERS inhibitor Salubrinal should be tested for neuroprotection against CIH-induced injury. PMID:24810321

  12. Chronic intermittent hypoxia creates the perfect storm with calamitous consequences for respiratory control.

    Science.gov (United States)

    O'Halloran, Ken D

    2016-06-01

    Obstructive sleep apnoea syndrome (OSAS) is a common respiratory disorder with devastating consequences for integrative body systems. A picture is emerging to illustrate wide-ranging deleterious consequences of disordered breathing during sleep for major homeostatic control systems, with considerable interest in cardiorespiratory and autonomic morbidity underpinning the development of hypertension. The vista is bleak when one also considers the link between OSAS and a host of other maladies. Exposure to chronic intermittent hypoxia (CIH), resulting from repeated obstructions of the pharyngeal airway, is a hallmark feature of OSAS that appears, in animal models, to drive the development and maintenance of several key morbidities. A growing body of evidence now points to aberrant respiratory plasticity at multiple levels following exposure to CIH. Herein, we review the experimental data revealing that CIH causes: respiratory muscle weakness and fatigue; impaired motor control of the upper airway; and, discordant respiratory rhythm and pattern generation. This multifaceted conspiracy creates the perfect storm with the potential to exacerbate OSAS-serving to establish an inescapable cycle of respiratory morbidity. Several pharmacological interventions in animal models appear wholly effective in preventing the calamitous consequences of CIH and may have application as adjunctive therapies in the treatment of OSAS. PMID:26528897

  13. Comparison of salbutamol given by intermittent positive-pressure breathing and pressure-packed aerosol in chronic asthma.

    OpenAIRE

    Anderson, P. B.; Goude, A; Peake, M D

    1982-01-01

    A double-blind crossover study was performed to compare 4 . 8 mg salbutamol given by pressure-packed aerosol and intermittent positive-pressure breathing nebulization in chronic asthmatic patients. The two delivery techniques produced similar changes in respiratory function and pulse rates. Given equal effect, a high-dose pressure-packed aerosol would have advantages in cost and convenience over nebulization techniques.

  14. Withdrawal from chronic, intermittent access to a highly palatable food induces depressive-like behavior in compulsive eating rats

    OpenAIRE

    Iemolo, Attilio; Valenza, Marta; Tozier, Lisa; Knapp, Clifford M.; Kornetsky, Conan; Steardo, Luca; Sabino, Valentina; Cottone, Pietro

    2012-01-01

    The increased availability of highly palatable foods is a major contributing factor toward the development of compulsive eating in obesity and eating disorders. It has been proposed that compulsive eating may develop as a form of self-medication to alleviate the negative emotional state associated with withdrawal from highly palatable foods. This study was aimed at determining whether withdrawal from chronic, intermittent access to a highly palatable food was responsible for the emergence of ...

  15. Vulnerabilidade programática na prevenção da transmissão materno-fetal da AIDS Program deficiencies in the prevention of maternal-fetal transmission of AIDS

    Directory of Open Access Journals (Sweden)

    Katia V. de O. Feliciano

    2002-08-01

    Full Text Available OBJETIVOS: avaliar a operacionalidade das ações de prevenção da transmissão materno-fetal do HIV na assistência pré-natal. MÉTODOS: estudo descritivo realizado na cidade do Recife, Pernambuco, de maio a julho de 1998, em 27 unidades dos seis Distritos Sanitários: 19 Centros de Saúde, duas Maternidades e seis do Programas de Saúde da Família (PSF. A organização foi caracterizada por meio de observações e entrevistas com gerentes e equipes técnicas. Acompanhou-se o processo de trabalho durante, no mínimo, dois turnos, em dias da semana aleatoriamente selecionados, totalizando 214 horas. As 355 gestantes presentes responderam um questionário: idade, antecedentes obstétricos, número de consultas, acessibilidade e orientações recebidas. RESULTADOS: em 63,0% das unidades houve demanda reprimida. Somente 41,6% das gestantes em seguimento tiveram a consulta atual agendada pelo serviço após a anterior. Em relação às doenças sexualmente transmissíveis: todos solicitaram o teste luético e 67,0% convocaram os parceiros quando o exame é positivo; não houve oferta universal do teste anti-HIV, nenhum realizou aconselhamento, apenas 26,7% dos médicos que identificaram gestantes de risco para AIDS solicitaram o teste e 19,8% das gestantes receberam orientações sobre essas doenças. CONCLUSÕES: a vulnerabilidade institucional na execução das ações programáticas e o amplo conjunto de necessidades de saúde da mulher em idade reprodutiva reiteram a importância de organizar o pré-natal.OBJECTIVES: to assess the effectiveness of maternal-fetal HIV transmission prevention programs at the pre-natal care stage. METHODS:a descriptive study was held in the city of Recife, Pernambuco, from May to July 1998, in 27 locations of six Sanitary Districts: 19 Health Centers, two Maternity Clinics and six Family Health Programs (PSF. The study focused on observation and interviews of managers and technical teams. Their work was followed

  16. Chronic intermittent hypoxia-induced deficits in synaptic plasticity and neurocognitive functions: a role for brain-derived neurotrophic factor

    Institute of Scientific and Technical Information of China (English)

    Hui XIE; Wing-ho YUNG

    2012-01-01

    Obstructive sleep apnea (OSA) is well known for its metabolic as well as neurobehavioral consequences.Chronic intermittent hypoxia (IH) is a major component of OSA.In recent years,substantial advances have been made in elucidating the cellular and molecular mechanisms underlying the effect of chronic IH on neurocognitive functions,many of which are based on studies in animal models.A number of hypotheses have been put forward to explain chronic IH-induced neurological dysfunctions.Among these,the roles of oxidative stress and apoptosis-related neural injury are widely accepted.Here,focusing on results derived from animal studies,we highlight a possible role of reduced expression of brain-derived neurotrophic factor (BDNF) in causing impairment in long-term synaptic plasticity and neurocognitive functions during chronic IH.The possible relationship between BDNF and previous findings on this subject will be elucidated.

  17. Effect of chronic intermittent hypoxia on theophylline metabolism in mouse liver

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-yang; ZENG Yi-ming; ZHANG Yi-xiang; WANG Wan-yu; WU Run-hua

    2013-01-01

    Background Chronic intermittent hypoxia (CIH) has been associated with abnormalities in the liver,which is the most important organ for drug metabolism.This study aimed to investigate the effect of CIH on theophylline metabolism in mouse liver.Methods Eight C57BL/6J mice were exposed to CIH for 12 weeks.Eight C57BL/6J mice were exposed to room air as a control group.Serum levels of alanine aminotransferase and aspartate aminotransferase were measured.Liver histology was observed by light and electron microscopy.Total hepatic cytochrome P450 concentration was measured.Hepatocytes were isolated and incubated with 15 mg/ml theophylline for four hours.After incubation,the theophylline concentration in the supernatant was measured and the theophylline metabolism rate was calculated.Results CIH did not affect the serum transaminase levels.Livers from mice exposed to CIH showed hepatocellular edema,and liver cells had fuzzy rough endoplasmic reticulum under the electron microscope.The theophylline metabolism rate was significantly inhibited by CIH compared with controls; (16.60±2.43)% vs.(21.58±4.52)% (P=0.02).The total liver cytochrome P450 concentration in the CIH group was significantly lower than in the control group;(0.83±0.08) vs.(1.13±0.21) mol/mg microsomal protein (P=0.004).Conclusion CIH decreases theophylline metabolism by mouse hepatocytes,which may correlate with the downregulation of cytochrome P450 expression by CIH.

  18. ERK signaling mediates enhanced angiotensin Ⅱ-induced rat aortic constriction following chronic intermittent hypoxia

    Institute of Scientific and Technical Information of China (English)

    GUO Xue-ling; DENG Yan; SHANG Jin; LIU Kui; XU Yong-jian; LIU Hui-guo

    2013-01-01

    Background Obstructive sleep apnea (OSA) has been recognized as an independent risk factor for systemic hypertension.The study investigated the functional consequences of chronic intermittent hypoxia (CIH) on aortic constriction induced by angiotensin Ⅱ (Ang Ⅱ) and the possible signaling involving ERK1/2 and contractile proteins such as myosin light chain kinase (MLCK),myosin phosphatase targeting subunit (MYPT1) and myosin light chain (MLC).Methods Male Wistar rats were randomly divided into CIH group and normoxia group and exposed to either CIH procedure or air-air cycles.Phosphorylation of ERK1/2,MYPT1 and MLC was assessed by Western blotting following constrictor studies in the presence or absence of PD98059 (10 μmol/L).Results CIH-exposure resulted in more body weight gain and elevated blood pressure,which could be attenuated by pretreatment with PD98059.Endothelium-removed aortic rings from CIH rats exhibited higher constrictor sensitivity to Ang Ⅱ (Emax:(138.56±5.78)% versus (98.45±5.31)% of KCI; pD2:7.98±0.14 versus 8.14±0.05,respectively).CIH procedure exerted complex effects on ERK expressions (total ERK1/2 decreased whereas the ratio of phosphorylated to total ERK1/2increased).CIH aortas had higher MLCK mRNA and basal phosphorylation of MYPT1 and MLC.In parallel to greater increases in phosphorylation of ERK1/2,MYPT1 and MLC,Ang Ⅱ-induced aortic constriction was significantly enhanced in CIH rats,which was largely reversed by PD98059.However vascular constriction of normoxia rats remained unchanged despite similar but smaller changing tendency of proteins phosphorylation.Conclusion These data suggest that CIH exposure results in aortic hyperresponsiveness to Ang Ⅱ,presumably owing to more activated ERK1/2 signaling pathway.

  19. The effect of oxidative stress in myocardial cell injury in mice exposed to chronic intermittent hypoxia

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-nan; ZHANG Jie-xin; LIU gan; QIU Yan; YANG Di; YIN Guo-yong; ZHANG Xi-long

    2010-01-01

    Background Obstructive sleep apnea syndrome (OSAS) is an important risk factor for cardiovascular diseases. Chronic intermittent hypoxia (CIH) is considered to be one of the most important causes of cardiovascular diseases in OSA patients. This repeated hypoxia and reoxygenation cycle is similar to hypoxia-reperfusion injury, which initiates oxidative stress. In this study, we observed cardiocytes injury induced by CIH and the effect of N-acetylcysteine (NAC). Methods Thirty ICR mice were randomly assigned to 3 groups: control, CIH and NAC (CIH+NAC) groups. Malondialdehyde (MDA) and superoxide dismutase (SOD) of cardiocyte homogenates were measured. Serum lipids were measured by an instrument method. Serum cardiac troponin I (cTnl) was detected by enzyme-linked immunosorbent assays (ELISA). Myocardium pathological sections were observed.Results (1) The SOD activity and MDA concentration of cardiocyte homogenates in the CIH group were significantly higher than in other groups (P <0.005). The MDA concentration of the NAC group was lower than that of the control group (P <0.01). (2) The serum cTnl concentration of the CIH and NAC groups was significantly higher than that of the control group (P<0.01). (3) Serum triglyceride levels in the NAC group were lower than in the other groups (P<0.01), while there were no significant differences in low density lipoprotein and high density lipoprotein among the three groups. (4) The degeneration of myocardium, transverse striation blurred, and fabric effusion were observed in tissue sections in the CIH and NAC groups. However, normal tissue was found in the control group.Conclusion The oxidative stress induced by CIH can injure cardiocytes and the injury effect can be partially inhibited by NAC.

  20. Adiponectin alleviates contractile dysfunction of genioglossus in rats exposed to chronic intermittent hypoxia

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-jing; LU Gan; DING Ning; HUANG Han-peng; DING Wen-xiao; ZHANG Xi-long

    2013-01-01

    Background Genioglossal dysfuntion takes an important role in pathogenesis of obstructive sleep apnea hypopnea syndrome (OSAHS) in which chronic intermittent hypoxia (CIH) is the major pathological origin.Recent studies have suggested genioglossal injury induced by CIH might be improved by adiponectin.The aim of this study was to investigate the effects of adiponectin on genioglossus contractile properties in rats exposed to CIH.Methods Thirty-nine healthy male Wistar rats were randomly divided into three groups:normal control (NC),CIH and adiponectin supplement (CIH+Ad) with 13 rats in each.Rats in NC were kept breathing normal air,while rats in CIH and CIH+Ad experienced the same CIH environment eight hours per day for 35 successive days.Rats in CIH+Ad were given intravenous adiponectin of 10 μg twice a week for 30 successive days.Rats in the NC and CIH were injected with normal saline as a control.After 35 days' CIH exposure,the levels of serum adiponectin and genioglossus contractile properties were compared.Results Serum adiponectin level was significantly lower in CIH than in NC (1210 ng/ml vs.2236 ng/ml).Serum adiponectin level in CIH+Ad (1844 ng/ml) was significantly higher than CIH but lower than NC.Twitch tension,time to peak tension,half relaxation time and tetanic tension were significantly lower in CIH than NC and improved in CIH+Ad.All mean tetanic fatigue indices decreased more rapidly in the first 20 seconds than during the subsequent 100 seconds.Tetanic fatigue indices in NC and CIH+Ad were significantly higher compared to CIH.Conclusions CIH could lead to hypoadiponectinaemia,impaired genioglossus contractile properties and decreased fatigue resistance in rats.Such changes could be partially offset by supplementation of adiponectin.

  1. Chronic intermittent fasting improves cognitive functions and brain structures in mice.

    Directory of Open Access Journals (Sweden)

    Liaoliao Li

    Full Text Available Obesity is a major health issue. Obesity started from teenagers has become a major health concern in recent years. Intermittent fasting increases the life span. However, it is not known whether obesity and intermittent fasting affect brain functions and structures before brain aging. Here, we subjected 7-week old CD-1 wild type male mice to intermittent (alternate-day fasting or high fat diet (45% caloric supplied by fat for 11 months. Mice on intermittent fasting had better learning and memory assessed by the Barnes maze and fear conditioning, thicker CA1 pyramidal cell layer, higher expression of drebrin, a dendritic protein, and lower oxidative stress than mice that had free access to regular diet (control mice. Mice fed with high fat diet was obese and with hyperlipidemia. They also had poorer exercise tolerance. However, these obese mice did not present significant learning and memory impairment or changes in brain structures or oxidative stress compared with control mice. These results suggest that intermittent fasting improves brain functions and structures and that high fat diet feeding started early in life does not cause significant changes in brain functions and structures in obese middle-aged animals.

  2. Impairment of cognitive function and reduced hippocampal cholinergic activity in a rat model of chronic intermittent hypoxia

    Institute of Scientific and Technical Information of China (English)

    Chunling Zhao; Yan Chen; Chunlai Zhang; Linya Lü; Qian Xu

    2011-01-01

    The present study established a rat model of chronic intermittent hypoxia (CIH) to simulate obstructive sleep apnea syndrome. CIH rats were evaluated for cognitive function using the Morris water maze, and neuronal pathology in the hippocampus was observed using hematoxylin-eosin staining. In addition, hippocampal choline acetyl transferase (ChAT) and nicotinic acetylcholine receptor (nAChR) expression was determined by immunohistochemistry. Our results revealed necrotic hippocampal neurons, decreased ChAT and nAChR expression, as well as cognitive impairment in CIH rats. These results suggest that hippocampal neuronal necrosis and decreased cholinergic activity may be involved in CIH-induced cognitive impairment in rats.

  3. Changes in carotid body and nTS neuronal excitability following neonatal sustained and chronic intermittent hypoxia exposure.

    Science.gov (United States)

    Mayer, C A; Wilson, C G; MacFarlane, P M

    2015-01-01

    We investigated whether pre-treatment with neonatal sustained hypoxia (SH) prior to chronic intermittent hypoxia (SH+CIH) would modify in vitro carotid body (CB) chemoreceptor activity and the excitability of neurons in the caudal nucleus of the solitary tract (nTS). Sustained hypoxia followed by CIH exposure simulates an oxygen paradigm experienced by extremely premature infants who developed persistent apnea. Rat pups were treated with 5 days of SH (11% O2) from postnatal age 1 (P1) followed by 10 days of subsequent chronic intermittent hypoxia (CIH, 5% O2/5 min, 8 h/day, between P6 and P15) as described previously (Mayer et al., Respir. Physiol. Neurobiol. 187(2): 167-75, 2013). At the end of SH+CIH exposure (P16), basal firing frequency was enhanced, and the hypoxic sensory response of single unit CB chemoafferents was attenuated. Further, basal firing frequency and the amplitude of evoked excitatory post-synaptic currents (ESPC's) of nTS neurons was augmented compared to age-matched rats raised in normoxia. These effects were unique to SH+CIH exposure as neither SH or CIH alone elicited any comparable effect on chemoafferent activity or nTS function. These data indicated that pre-treatment with neonatal SH prior to CIH exposure uniquely modified mechanisms of peripheral (CB) and central (nTS) neural function in a way that would be expected to disturb the ventilatory response to acute hypoxia.

  4. Validation of housekeeping genes in the brains of rats submitted to chronic intermittent hypoxia, a sleep apnea model.

    Science.gov (United States)

    Julian, Guilherme Silva; de Oliveira, Renato Watanabe; Perry, Juliana Cini; Tufik, Sergio; Chagas, Jair Ribeiro

    2014-01-01

    Obstructive sleep apnea (OSA) is a syndrome characterized by intermittent nocturnal hypoxia, sleep fragmentation, hypercapnia and respiratory effort, and it has been associated with several complications, such as diabetes, hypertension and obesity. Quantitative real-time PCR has been performed in previous OSA-related studies; however, these studies were not validated using proper reference genes. We have examined the effects of chronic intermittent hypoxia (CIH), which is an experimental model mainly of cardiovascular consequences of OSA, on reference genes, including beta-actin, beta-2-microglobulin, glyceraldehyde-3-phosphate dehydrogenase, hypoxanthine guanine phosphoribosyl transferase and eukaryotic 18S rRNA, in different areas of the brain. All stability analyses were performed using the geNorm, Normfinder and BestKeeper software programs. With exception of the 18S rRNA, all of the evaluated genes were shown to be stable following CIH exposure. However, gene stability rankings were dependent on the area of the brain that was analyzed and varied according to the software that was used. This study demonstrated that CIH affects various brain structures differently. With the exception of the 18S rRNA, all of the tested genes are suitable for use as housekeeping genes in expression analyses.

  5. Validation of housekeeping genes in the brains of rats submitted to chronic intermittent hypoxia, a sleep apnea model.

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    Guilherme Silva Julian

    Full Text Available Obstructive sleep apnea (OSA is a syndrome characterized by intermittent nocturnal hypoxia, sleep fragmentation, hypercapnia and respiratory effort, and it has been associated with several complications, such as diabetes, hypertension and obesity. Quantitative real-time PCR has been performed in previous OSA-related studies; however, these studies were not validated using proper reference genes. We have examined the effects of chronic intermittent hypoxia (CIH, which is an experimental model mainly of cardiovascular consequences of OSA, on reference genes, including beta-actin, beta-2-microglobulin, glyceraldehyde-3-phosphate dehydrogenase, hypoxanthine guanine phosphoribosyl transferase and eukaryotic 18S rRNA, in different areas of the brain. All stability analyses were performed using the geNorm, Normfinder and BestKeeper software programs. With exception of the 18S rRNA, all of the evaluated genes were shown to be stable following CIH exposure. However, gene stability rankings were dependent on the area of the brain that was analyzed and varied according to the software that was used. This study demonstrated that CIH affects various brain structures differently. With the exception of the 18S rRNA, all of the tested genes are suitable for use as housekeeping genes in expression analyses.

  6. Validation of Housekeeping Genes in the Brains of Rats Submitted to Chronic Intermittent Hypoxia, a Sleep Apnea Model

    Science.gov (United States)

    Julian, Guilherme Silva; de Oliveira, Renato Watanabe; Perry, Juliana Cini; Tufik, Sergio; Chagas, Jair Ribeiro

    2014-01-01

    Obstructive sleep apnea (OSA) is a syndrome characterized by intermittent nocturnal hypoxia, sleep fragmentation, hypercapnia and respiratory effort, and it has been associated with several complications, such as diabetes, hypertension and obesity. Quantitative real-time PCR has been performed in previous OSA-related studies; however, these studies were not validated using proper reference genes. We have examined the effects of chronic intermittent hypoxia (CIH), which is an experimental model mainly of cardiovascular consequences of OSA, on reference genes, including beta-actin, beta-2-microglobulin, glyceraldehyde-3-phosphate dehydrogenase, hypoxanthine guanine phosphoribosyl transferase and eukaryotic 18S rRNA, in different areas of the brain. All stability analyses were performed using the geNorm, Normfinder and BestKeeper software programs. With exception of the 18S rRNA, all of the evaluated genes were shown to be stable following CIH exposure. However, gene stability rankings were dependent on the area of the brain that was analyzed and varied according to the software that was used. This study demonstrated that CIH affects various brain structures differently. With the exception of the 18S rRNA, all of the tested genes are suitable for use as housekeeping genes in expression analyses. PMID:25289636

  7. Moléculas que participan en el transporte de hierro materno-fetal: importancia del receptor 1 de transferrina y de la ferroportina en la placenta humana = Molecules implicated in maternal-fetal iron transport across the placental barrier: Role of Transferrin Receptor 1 and Ferroportin

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    Corrales Agudelo, Lady Vanessa

    2011-03-01

    Full Text Available La adecuada transferencia placentaria de hierro es crucial para satisfacer los altos requerimientos del feto y promover su adecuado crecimiento y desarrollo intrauterino; de otra parte, contribuye a prevenir la ferropenia y la anemia, entidades altamente prevalentes en los lactantes durante los primeros dos años de edad, que se asocian con mayor morbilidad y mortalidad en la infancia. La placenta es un órgano capaz de realizar diferentes adaptaciones en la producción de moléculas que participan en el transporte de hierro materno-fetal en respuesta al estado de hierro celular, para proveer la mayor disponibilidad de este mineral al feto. Esta revisión, pretende acercar al lector a los mecanismos metabólicos y moleculares relacionados con la captación, el transporte y la salida de hierro por la placenta hacia el feto, así como su regulación, para proporcionar elementos que le permitan comprender en forma integrada, la importancia de un adecuado estado de hierro materno antes y durante la gestación.

  8. The effects of acute intermittent hypoxia on cardiovascular parameters in normotensive and chronic hypobaric hypoxia-induced hypertensive rabbits.

    Science.gov (United States)

    Yaman, Muhittin O; Guner, Ibrahim; Uzun, Hafize; Sahin, Gulderen; Yelmen, Nermin

    2014-01-01

    The effects of both chronic hypoxia and acute intermittent hypoxia (AIH) on cardiovascular system are unclear. We designed this study to develop a rabbit model of hypertension by exposure to chronic hypobaric hypoxia (CHH) and to investigate the effects of AIH on hypertensive rabbits. Present study was performed in 13 albino rabbits that divided into CHH and control groups. To develop hypertension, the rabbits were placed in a hypobaric chamber (390 mmHg; 22 hours/day, 30 days). Afterwards, AIH protocol was applied (8% FIO2 (Fraction of Inspired Oxygen) 1 min + 5 min normoxia, 20 cycles, 2 hours) to rabbits anesthetized with urethane and alpha-chloralose. Mean arterial pressure (MAP), heart rate (HR) and hematocrit values have been determined. Also asymmetric dimethylarginine (ADMA), endothelial nitric oxide synthase (eNOS), endothelin-1 and norepinephrine values have been analyzed in blood. We developed a model of hypertension in rabbits via exposure to severe CHH and we believe that ADMA is an important parameter in the development and permanence of CHH-induced hypertension. The main finding of this sudy was the depressor effect of AIH on blood pressure and heart rate in CHH- induced hypertension model. Finally, we believe that AIH protocol may be applicable for prevention and treatment of hypertension if properly developed. PMID:24448370

  9. Chronic Cervicogenic Tinnitus Rapidly Resolved by Intermittent Use of Cervical Collar

    OpenAIRE

    Bechter, Karl; Wieland, Martin; Hamann, Gerhard F

    2016-01-01

    Introduction Cervicogenic tinnitus is not a generally accepted pathogenetic subtype, which might be subsumed under the concept of somatosensory tinnitus. After the personal experience of therapy-resistant tinnitus in context with a cervical pain syndrome (CPS) and successful add-on treatment with cervical collar (CC), the idea was pursued in several individual treatments in patients. Patients and methods Reporting one particular case with chronic tinnitus, considered untreatable, t...

  10. Intermittent and continuous high-intensity exercise training induce similar acute but different chronic muscle adaptations.

    Science.gov (United States)

    Cochran, Andrew J R; Percival, Michael E; Tricarico, Steven; Little, Jonathan P; Cermak, Naomi; Gillen, Jenna B; Tarnopolsky, Mark A; Gibala, Martin J

    2014-05-01

    High-intensity interval training (HIIT) performed in an 'all-out' manner (e.g. repeated Wingate tests) is a time-efficient strategy to induce skeletal muscle remodelling towards a more oxidative phenotype. A fundamental question that remains unclear, however, is whether the intermittent or 'pulsed' nature of the stimulus is critical to the adaptive response. In study 1, we examined whether the activation of signalling cascades linked to mitochondrial biogenesis was dependent on the manner in which an acute high-intensity exercise stimulus was applied. Subjects performed either four 30 s Wingate tests interspersed with 4 min of rest (INT) or a bout of continuous exercise (CONT) that was matched for total work (67 ± 7 kJ) and which required ∼4 min to complete as fast as possible. Both protocols elicited similar increases in markers of adenosine monophosphate-activated protein kinase (AMPK) and p38 mitogen-activated protein kinase activation, as well as Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) mRNA expression (main effects for time, P ≤ 0.05). In study 2, we determined whether 6 weeks of the CONT protocol (3 days per week) would increase skeletal muscle mitochondrial content to a similar extent to what we have previously reported after 6 weeks of INT. Despite similar acute signalling responses to the CONT and INT protocols, training with CONT did not increase the maximal activity or protein content of a range of mitochondrial markers. However, peak oxygen uptake was higher after CONT training (from 45.7 ± 5.4 to 48.3 ± 6.5 ml kg(-1) min(-1); P muscle adaptations to low-volume, all-out HIIT. Despite the lack of skeletal muscle mitochondrial adaptations, our data show that a training programme based on a brief bout of high-intensity exercise, which lasted <10 min per session including warm-up, and performed three times per week for 6 weeks, improved peak oxygen uptake in young healthy subjects.

  11. Mother-to-child transmission of different HIV-1 subtypes among ARV Naïve infected pregnant women in Nigeria Transmissão materno-fetal de diferentes subtipos de HIV-1 entre gestantes infectadas na Nigéria

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    G.N. Odaibo

    2006-04-01

    Full Text Available The rate of mother-to-child transmission (MTCT of HIV as well as the implications of the circulating multiple subtypes to MTCT in Nigeria are not known. This study was therefore undertaken to determine the differential rates of MTCT of HIV-1 subtypes detected among infected pregnant women before ARV intervention therapy became available in Nigeria. Twenty of the HIV-positive women who signed the informed consent form during pregnancy brought their babies for follow-up testing at age 18-24 months. Plasma samples from both mother and baby were tested for HIV antibody at the Department of Virology, UCH, Ibadan, Nigeria. All positive samples (plasma and peripheral blood mononuclear cells - PBMCs were shipped to the Institute of Tropical Medicine, Antwerp, Belgium, where the subtype of the infecting virus was determined using the HMA technique. Overall, a mother-to-child HIV transmission rate of 45% was found in this cohort. Specifically, 36.4%, 66.7% and 100% of the women infected with HIV-1 CRF02 (IbNg, G and B, respectively, transmitted the virus to their babies. As far as it can be ascertained, this is the first report on the rate of MTCT of HIV in Nigeria. The findings reported in this paper will form a useful reference for assessment of currently available therapeutic intervention of MTCT in the country.A taxa de transmissão materno-fetal (MTCT do HIV bem como as implicações dos múltiplos subtipos circulantes para MTCT na Nigéria não são conhecidos. Este estudo foi realizado para determinar as diferentes taxas de MTCT dos subtipos de HIV-1 detectados entre gestantes infectadas antes que a administração da terapia ARV estivesse disponível na Nigéria. Vinte das mulheres HIV positivas que assinaram o consentimento durante a gravidez trouxeram seus filhos para seguimento na idade de 18-24 meses. Amostras de plasma de ambos, mãe e filho foram testadas para anticorpos HIV no Departamento de Virologia, UCH, Ibadan, Nigéria. Todas as

  12. Cardiac Response to Chronic Intermittent Hypoxia with a Transition from Adaptation to Maladaptation: The Role of Hydrogen Peroxide

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    Xia Yin

    2012-01-01

    Full Text Available Obstructive sleep apnea (OSA is a highly prevalent respiratory disorder of sleep, and associated with chronic intermittent hypoxia (CIH. Experimental evidence indicates that CIH is a unique physiological state with potentially “adaptive” and “maladaptive” consequences for cardio-respiratory homeostasis. CIH is also a critical element accounting for most of cardiovascular complications of OSA. Cardiac response to CIH is time-dependent, showing a transition from cardiac compensative (such as hypertrophy to decompensating changes (such as failure. CIH-provoked mild and transient oxidative stress can induce adaptation, but severe and persistent oxidative stress may provoke maladaptation. Hydrogen peroxide as one of major reactive oxygen species plays an important role in the transition of adaptive to maladaptive response to OSA-associated CIH. This may account for the fact that although oxidative stress has been recognized as a driver of cardiac disease progression, clinical interventions with antioxidants have had little or no impact on heart disease and progression. Here we focus on the role of hydrogen peroxide in CIH and OSA, trying to outline the potential of antioxidative therapy in preventing CIH-induced cardiac damage.

  13. Effects of chronic intermittent hypoxia on the cognitive function and neuron structure of hippocampus in mouse model of Parkinson's disease

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    LIU Hai-lin

    2013-06-01

    Full Text Available Objective To investigate the effects of chronic intermittent hypoxia (CIH on the cognitive function, neuron structure and synaptophysin (Syn expression of the hippocampus in mouse model of Parkinson's disease (PD. Methods A hypoxia-reoxygen device was used to prepare the model of CIH. Meanwhile, the PD mouse model was built by intraperitoneal injection of paraquat (PQ. The cognitive function was evaluated by Y-type electric maze and step-down test. Syn expression in the hippocampus was estimated by immunohistochemistry. The neuron structure in the hippocampus was observed by HE staining, Nissl staining and the electron microscope. Results Comparing to control group, a significant decrease was found in learning and memorizing performance (P < 0.05, for all and the amount of neuron, while a significant increase was seen in total reaction time (TRT and error reaction (ER in Y-type electric maze and step-down test and the gray value of Syn in the hippocampus in PQ, CIH, and PQ + CIH groups. Various degrees of anomaly were observed in neuron structure of hippocampus by HE staining, Nissl staining and electron microscopy in PQ, CIH, and PQ + CIH groups, while presented most obviously in thelatter group. Conclusion The PQ-induced impairment of cognitive function in PD model mice was aggravated by CIH, which may be related to the damage of neuron structure and the decrease of synaptic function in hippocampus.

  14. Effect of Intermittent versus Chronic Calorie Restriction on Tumor Incidence: A Systematic Review and Meta-Analysis of Animal Studies

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    Chen, Yalan; Ling, Lifeng; Su, Guanglei; Han, Ming; Fan, Xikang; Xun, Pengcheng; Xu, Guangfei

    2016-01-01

    Both chronic calorie restriction (CCR) and intermittent calorie restriction (ICR) have shown anticancer effects. However, the direct evidence comparing ICR to CCR with respect to cancer prevention is controversial and inconclusive. PubMed and Web of Science were searched on November 25, 2015. The relative risk (RR) [95% confidence interval (CI)] was calculated for tumor incidence, and the standardised mean difference (95% CI) was computed for levels of serum insulin-like growth factor-1 (IGF-1), leptin, and adiponectin using a random-effects meta-analysis. Sixteen studies were identified, including 11 using genetically engineered mouse models (908 animals with 38–76 weeks of follow-up) and 5 using chemically induced rat models (379 animals with 7–18 weeks of follow-up). Compared to CCR, ICR decreased tumor incidence in genetically engineered models (RR = 0.57; 95% CI: 0.37, 0.88) but increased the risk in chemically induced models (RR = 1.53, 95% CI: 1.13, 2.06). It appears that ICR decreases IGF-1 and leptin and increases adiponectin in genetically engineered models. Thus, the evidence suggests that ICR exerts greater anticancer effect in genetically engineered mouse models but weaker cancer prevention benefit in chemically induced rat models as compared to CCR. Further studies are warranted to confirm our findings and elucidate the mechanisms responsible for these effects. PMID:27653140

  15. Effects of Gestational and Postnatal Exposure to Chronic Intermittent Hypoxia on Diaphragm Muscle Contractile Function in the Rat

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    McDonald, Fiona B.; Dempsey, Eugene M.; O'Halloran, Ken D.

    2016-01-01

    Alterations to the supply of oxygen during early life presents a profound stressor to physiological systems with aberrant remodeling that is often long-lasting. Chronic intermittent hypoxia (CIH) is a feature of apnea of prematurity, chronic lung disease, and sleep apnea. CIH affects respiratory control but there is a dearth of information concerning the effects of CIH on respiratory muscles, including the diaphragm—the major pump muscle of breathing. We investigated the effects of exposure to gestational CIH (gCIH) and postnatal CIH (pCIH) on diaphragm muscle function in male and female rats. CIH consisted of exposure in environmental chambers to 90 s of hypoxia reaching 5% O2 at nadir, once every 5 min, 8 h a day. Exposure to gCIH started within 24 h of identification of a copulation plug and continued until day 20 of gestation; animals were studied on postnatal day 22 or 42. For pCIH, pups were born in normoxia and within 24 h of delivery were exposed with dams to CIH for 3 weeks; animals were studied on postnatal day 22 or 42. Sham groups were exposed to normoxia in parallel. Following gas exposures, diaphragm muscle contractile, and endurance properties were examined ex vivo. Neither gCIH nor pCIH exposure had effects on diaphragm muscle force-generating capacity or endurance in either sex. Similarly, early life exposure to CIH did not affect muscle tolerance of severe hypoxic stress determined ex vivo. The findings contrast with our recent observation of upper airway dilator muscle weakness following exposure to pCIH. Thus, the present study suggests a relative resilience to hypoxic stress in diaphragm muscle. Co-ordinated activity of thoracic pump and upper airway dilator muscles is required for optimal control of upper airway caliber. A mismatch in the force-generating capacity of the complementary muscle groups could have adverse consequences for the control of airway patency and respiratory homeostasis. PMID:27462274

  16. The effects of intermittent fasting during the month of Ramadan in chronic haemodialysis patients in a tropical climate country.

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    Wan Ahmad Hafiz Wan Md Adnan

    Full Text Available BACKGROUND: Chronic kidney disease is an emerging problem in the majority Muslim countries. Despite the uncertainties of the risks involved, some Muslim patients undergoing chronic haemodialysis choose to observe intermittent fasting during the month of Ramadan. This study aims to investigate the effect of Ramadan fasting in haemodialysis patients residing in a tropical climate country. METHODS: This prospective cross sectional study recruited Muslim patients on regular haemodialysis from three haemodialysis centres in Kuala Lumpur from 15th July 2011 to 29th August 2011. Patients who fasted for any number of days were included (n = 35, 54% female, age 54±11 years. 89% of patients fasted for more than 15 days and 49% were diabetics. Dialysis parameters and blood samples were obtained one week prior to Ramadan and during the last week of Ramadan. The differences in dialysis parameters and biochemical values pre- and end-Ramadan were examined using paired t-test. RESULTS: Both pre- and post-dialysis weight were significantly decreased during Ramadan fasting compared to the month prior (p = <0.001. There was a significant decrease in the amount of ultrafiltration (p = 0.002. There were no significant differences in dry weight, inter-dialytic weight gain, mean urea reduction ratio or blood pressure measurements comparing pre- and end of Ramadan fasting. There was a significant increase in serum albumin level (p = 0.006 and decrease in serum phosphate level (p = 0.02 at the end of Ramadan. CONCLUSION: Ramadan fasting is associated with reduced weight, improved serum albumin and phosphate level in our population of haemodialysis patients. A larger multi-centre study will allow us to understand more about the effects of fasting in this population.

  17. Prevalence and severity of pain in adult end-stage renal disease patients on chronic intermittent hemodialysis: a systematic review

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    Brkovic T

    2016-06-01

    Full Text Available Tonci Brkovic,1 Eliana Burilovic,2 Livia Puljak3 1Department of Internal Medicine, Division of Nephrology, 2Department of Psychiatry, University Hospital Split, 3Department of Anatomy, Histology and Embryology, Laboratory for Pain Research, University of Split School of Medicine, Split, Croatia Objectives: Understanding the epidemiology of pain in patients on hemodialysis (HD is crucial for further improvement in managing pain. The aim of this study was to systematically review available evidence on the prevalence and severity of pain in adult end-stage renal disease patients on chronic intermittent HD. Materials and methods: We carried out a systematic review of the literature and developed a comprehensive search strategy based on search terms on pain and HD. We searched the databases MEDLINE, Scopus, PsycINFO, and CINAHL from the earliest date of each database to July 24, 2014. Manuscripts in all languages were taken into consideration. Two authors performed each step independently, and all disagreements were resolved after discussion with the third author. The quality of studies was estimated using the STROBE checklist and Cochrane risk-of-bias tool.Results: We included 52 studies with 6,917 participants. The prevalence of acute and chronic pain in HD patients was up to 82% and 92%, respectively. A considerable number of patients suffered from severe pain. Various locations and causes of pain were described, with most of the studies reporting pain in general, pain related to arteriovenous access, headache, and musculoskeletal pain.Conclusion: The findings of this systematic review indicate high prevalence of pain in HD patients and considerable gaps and limitations in the available evidence. Pain in this population should be recognized as a considerable health concern, and the nephrology community should promote pain management in HD patients as a clinical and research priority to improve patients’ quality of life and pain

  18. Time-Course Analysis of Brain Regional Expression Network Responses to Chronic Intermittent Ethanol and Withdrawal: Implications for Mechanisms Underlying Excessive Ethanol Consumption

    OpenAIRE

    Smith, Maren L.; Lopez, Marcelo F; Archer, Kellie J; Wolen, Aaron R.; Howard C Becker; Miles, Michael F.

    2016-01-01

    Long lasting abusive consumption, dependence, and withdrawal are characteristic features of alcohol use disorders (AUD). Mechanistically, persistent changes in gene expression are hypothesized to contribute to brain adaptations leading to ethanol toxicity and AUD. We employed repeated chronic intermittent ethanol (CIE) exposure by vapor chamber as a mouse model to simulate the cycles of ethanol exposure and withdrawal commonly seen with AUD. This model has been shown to induce progressive eth...

  19. Changes in genioglossus and their association with serum adiponectin levels in rats subjected to chronic intermittent hypoxia

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-feng; WANG Ya-hui; LI Qin; ZHANG Xi-long; SHEN Jiu-cheng; LI Chong; LIU Hao

    2010-01-01

    Background The genioglossus (GG) is involved in the maintenance of an open airway for effective breathing.Although the pathogenesis of obstructive sleep apnea hypopnea syndrome (OSAHS) was closely associated with GG dysfunction,its causes and possible treatment have not been elucidated.The aim of the study was to investigate the effects of chronic intermittent hypoxia (CIH) on serum adiponectin levels, electromyograph (EMG) activity and ultrastructure of GG, as well as the effect of an adiponectin supplement in anesthetized rats.Methods Forty-two healthy male Wistar rats were randomly divided into normal control (A), CIH (B) and adiponectin treatment (C) groups, 14 rats in each group.CIH was performed eight hours per day for five weeks in both groups B and C.Group C received transvenous injection of adiponectin at the dosage of 10 μg per injection, twice a week for five weeks.At the end of the 5th week the GG EMG voltage was measured and compared among the three groups.Transmission electron microscope was used to observe the ultrastructure of the GG.Results CIH caused significant hypoadiponectinemia, weakened activity of GG EMG at both baseline and hypoxia stimulation, and induced ultrastructural pathological changes, such as, myofibril discontinuities, lysis of myofilament,edema of mitochondria and disruption of cristae, vacuolus and lysis of some mitochondria.Venous supplement of adiponectin improved the above pathological changes resulting from CIH.Conclusion CIH resulted in pathological changes in GG's EMG and ultrastructure, which could be improved by supplement of adiponectin and be associated with hypoadiponectinemia caused by ClH.

  20. Repeated Cycles of Chronic Intermittent Ethanol Exposure Increases Basal Glutamate in the Nucleus Accumbens of Mice without affecting glutamate transport

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    William C. Griffin

    2015-02-01

    Full Text Available Repeated cycles of chronic intermittent ethanol (CIE exposure increase voluntary consumption of ethanol in mice. Previous work has shown that extracellular glutamate in the nucleus accumbens (NAc is significantly elevated in ethanol dependent mice and that pharmacologically manipulating glutamate concentrations in the NAc will alter ethanol drinking, indicating that glutamate homeostasis plays a crucial role in ethanol drinking in this model. The present studies were designed to measure extracellular glutamate at a time point in which mice would ordinarily be allowed voluntary access to ethanol in the CIE model and, additionally, to measure glutamate transport capacity in the NAc at the same time point. Extracellular glutamate was measured using quantitative microdialysis procedures. Glutamate transport capacity was measured under Na+ dependent and Na+ independent conditions to determine whether the function of excitatory amino acid transporters (EAATs; also known as system XAG or of system Xc- (Glial cysteine-glutamate exchanger was influenced by CIE exposure. The results of the quantitative microdialysis experiment confirm increased extracellular glutamate (~2 –fold in the NAc of CIE exposed mice (i.e. ethanol-dependent compared to non-dependent mice in the NAc, consistent with earlier work. However, the increase in extracellular glutamate was not due to altered transporter function in the NAc of ethanol-dependent mice, because neither Na+ dependent nor Na+ independent glutamate transport was significantly altered by CIE exposure. These findings point to the possibility that hyperexcitability of cortical-striatal pathways underlies the increases in extracellular glutamate found in the nucleus accumbens of ethanol-dependent mice.

  1. Analysis of the stability of housekeeping gene expression in the left cardiac ventricle of rats submitted to chronic intermittent hypoxia.

    Science.gov (United States)

    Julian, Guilherme Silva; Oliveira, Renato Watanabe de; Tufik, Sergio; Chagas, Jair Ribeiro

    2016-01-01

    Obstructive sleep apnea (OSA) has been associated with oxidative stress and various cardiovascular consequences, such as increased cardiovascular disease risk. Quantitative real-time PCR is frequently employed to assess changes in gene expression in experimental models. In this study, we analyzed the effects of chronic intermittent hypoxia (an experimental model of OSA) on housekeeping gene expression in the left cardiac ventricle of rats. Analyses via four different approaches-use of the geNorm, BestKeeper, and NormFinder algorithms; and 2-ΔCt (threshold cycle) data analysis-produced similar results: all genes were found to be suitable for use, glyceraldehyde-3-phosphate dehydrogenase and 18S being classified as the most and the least stable, respectively. The use of more than one housekeeping gene is strongly advised. RESUMO A apneia obstrutiva do sono (AOS) tem sido associada ao estresse oxidativo e a várias consequências cardiovasculares, tais como risco aumentado de doença cardiovascular. A PCR quantitativa em tempo real é frequentemente empregada para avaliar alterações na expressão gênica em modelos experimentais. Neste estudo, analisamos os efeitos da hipóxia intermitente crônica (um modelo experimental de AOS) na expressão de genes de referência no ventrículo cardíaco esquerdo de ratos. Análises a partir de quatro abordagens - uso dos algoritmos geNorm, BestKeeper e NormFinder e análise de dados 2-ΔCt (ciclo limiar) - produziram resultados semelhantes: todos os genes mostraram-se adequados para uso, sendo que gliceraldeído-3-fosfato desidrogenase e 18S foram classificados como o mais e o menos estável, respectivamente. A utilização de mais de um gene de referência é altamente recomendada. PMID:27383935

  2. Chronic intermittent hypoxia depresses afferent neurotransmission in NTS neurons by a reduction in the number of active synapses.

    Science.gov (United States)

    Almado, Carlos Eduardo L; Machado, Benedito H; Leão, Ricardo M

    2012-11-21

    Long-term synaptic plasticity has been recently described in brainstem areas associated to visceral afferent sensory integration. Chronic intermittent hypoxia (CIH), an animal model for studying obstructive sleep apnea in humans, depresses the afferent neurotransmission in nucleus tractus solitarii (NTS) neurons, which affect respiratory and autonomic regulation. Here we identified the synaptic mechanisms of CIH-induced depression of the afferent neurotransmission in NTS neurons in juvenile rats. We verified that CIH reduced the amplitude of both NMDA and non-NMDA glutamatergic excitatory currents (eEPSCs) evoked by tractus solitarii stimulation (TS-eEPSC) of second-order neurons in the NTS. No changes were observed in release probability, evidenced by absence of any CIH-elicited effects on short-term depression and failures in EPSCs evoked in low calcium. CIH also produced no changes in TS-eEPSC quantal size, since the amplitudes of both low calcium-evoked EPSCs and asynchronous TS-eEPSCs (evoked in the presence of Sr(2+)) were unchanged. Using single TS afferent fiber stimulation in slices from control and CIH rats we clearly show that CIH reduced the quantal content of the TS-eEPSCs without affecting the quantal size or release probability, suggesting a reduction in the number of active synapses as the mechanism of CIH induced TS-eEPSC depression. In accordance with this concept, the input-output relationship of stimulus intensity and TS-eEPSC amplitude shows an early saturation in CIH animals. These findings open new perspectives for a better understanding of the mechanisms underlying the synaptic plasticity in the brainstem sensory neurons under challenges such as those produced by CIH in experimental and pathological conditions.

  3. Chronic intermittent hypoxia from pedo-stage decreases glucose transporter 4 expression in adipose tissue and causes insulin resistance

    Institute of Scientific and Technical Information of China (English)

    CHEN Lin; CAO Zhao-long; HAN Fang; GAO Zhan-cheng; HE Quan-ying

    2010-01-01

    Background The persistence of sleep disordered breathing (SDB) symptoms after tonsil and/or adenoid (T&A) surgery are common in children with obstructive sleep apnea (OSA). We tested the hypothesis that disturbances of glucose transporters (GLUTs) in intraabdominal adipose tissue caused by chronic intermittent hypoxia (CIH) from the pedo-period could facilitate the appearance of periphery insulin resistance in Sprague-Dawley (SD) rats. We tested the hypothesis that the changes of GLUTs in adipose tissue may be one of the reasons for persistent SDB among clinical OSA children after T&A surgery.Methods Thirty 21-day-old SD rats were randomly divided into a CIH group, a chronic continuous hypoxia (CCH) group, and a normal oxygen group (control group) and exposed for 40 days. The changes of weight, fasting blood glucose and fasting blood insulin levels were measured. Hyperinsulinemic-euglycemic clamp techniques were used to measure insulin resistance in each animal. Real-time quantitative PCR and Westem blotting were used to measure GLUT Mrna and proteins in intraabdominal adipose tissue. Additional intraabdomial white adipose tissue (WAT) was also processed into paraffin sections and directly observed for GLUTs1-4 expression.Results When compared with control group, CIH increased blood fasting insulin levels, (245.07±53.89) pg/ml vs. (168.63±38.70) pg/ml, p=0.038, and decreased the mean glucose infusion rate (GIR), (7.25±1.29) mg·kg~(-1)·min~(-1) vs. (13.34±1.54) mg·kg~(-1)·min~(-1), P<0.001. GLUT-4 Mrna and protein expression was significantly reduced after CIH compared with CCH or normal oxygen rats, 0.002±0.002 vs. 0.039±0.009, P <0.001; 0.642±0.073 vs. 1.000±0.103, P=0.035.Conclusions CIH in young rats could induce insulin resistance via adverse effects on glycometabolism. These findings emphasize the importance of early detection and treatment of insulin insensitivity in obese childhood OSA.

  4. Mice Exposed to Chronic Intermittent Hypoxia Simulate Clinical Features of Deficiency of both Qi and Yin Syndrome in Traditional Chinese Medicine

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    Chengzhi Chai

    2011-01-01

    Full Text Available Deficiency of both Qi and Yin Syndrome (DQYS is one of the common syndromes in traditional Chinese medicine (TCM, mainly characterized by tiredness, emaciation, anorexia, fidget, palpitation and rapid pulse, and so forth. Currently, there is no available animal model which can reflect the clinical features of this syndrome. In the present paper, we observed the time-course changes of whole behavior, body weight, food intake, locomotive activity and electrocardiogram in mice exposed to chronic intermittent hypoxia for 6 weeks, and measured bleeding time at last according to the clinical features of DQYS and one key pathological factor. The results showed that the mice exposed to intermittent hypoxia for certain time presented lackluster hair, dull looking hair, resistance, attacking, body weight loss, food intake decline, locomotive activity decrease, heart rate quickening and T wave elevating, which were similar to the major clinical features of DQYS. Meanwhile, bleeding time shortening was also found, which was consistent with the clinical fact that DQYS often accompanied with blood stasis. The possible explanation was also outlined according to the available literature. Such findings suggested chronic intermittent hypoxia could induce similar symptoms and signs in mice accorded with the clinical features of DQYS, which provided a suitable animal model for evaluation of drugs for the treatment of this syndrome and further exploration of pathological process or correlation of the syndrome and related diseases.

  5. Mice Exposed to Chronic Intermittent Hypoxia Simulate Clinical Features of Deficiency of both Qi and Yin Syndrome in Traditional Chinese Medicine.

    Science.gov (United States)

    Chai, Chengzhi; Kou, Junping; Zhu, Danni; Yan, Yongqing; Yu, Boyang

    2011-01-01

    Deficiency of both Qi and Yin Syndrome (DQYS) is one of the common syndromes in traditional Chinese medicine (TCM), mainly characterized by tiredness, emaciation, anorexia, fidget, palpitation and rapid pulse, and so forth. Currently, there is no available animal model which can reflect the clinical features of this syndrome. In the present paper, we observed the time-course changes of whole behavior, body weight, food intake, locomotive activity and electrocardiogram in mice exposed to chronic intermittent hypoxia for 6 weeks, and measured bleeding time at last according to the clinical features of DQYS and one key pathological factor. The results showed that the mice exposed to intermittent hypoxia for certain time presented lackluster hair, dull looking hair, resistance, attacking, body weight loss, food intake decline, locomotive activity decrease, heart rate quickening and T wave elevating, which were similar to the major clinical features of DQYS. Meanwhile, bleeding time shortening was also found, which was consistent with the clinical fact that DQYS often accompanied with blood stasis. The possible explanation was also outlined according to the available literature. Such findings suggested chronic intermittent hypoxia could induce similar symptoms and signs in mice accorded with the clinical features of DQYS, which provided a suitable animal model for evaluation of drugs for the treatment of this syndrome and further exploration of pathological process or correlation of the syndrome and related diseases.

  6. Adiponectin protects rat myocardium against chronic intermittent hypoxia-induced injury via inhibition of endoplasmic reticulum stress.

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    Wenxiao Ding

    Full Text Available Obstructive sleep apnea syndrome (OSAS is associated with many cardiovascular disorders such as heart failure, hypertension, atherosclerosis, and arrhythmia and so on. Of the many associated factors, chronic intermittent hypoxia (CIH in particular is the primary player in OSAS. To assess the effects of CIH on cardiac function secondary to OSAS, we established a model to study the effects of CIH on Wistar rats. Specifically, we examined the possible underlying cellular mechanisms of hypoxic tissue damage and the possible protective role of adiponectin against hypoxic insults. In the first treatment group, rats were exposed to CIH conditions (nadir O2, 5-6% for 8 hours/day, for 5 weeks. Subsequent CIH-induced cardiac dysfunction was measured by echocardiograph. Compared with the normal control (NC group, rats in the CIH-exposed group experienced elevated levels of left ventricular end-systolic dimension and left ventricular end-systolic volume and depressed levels of left ventricular ejection fraction and left ventricular fractional shortening (p<0.05. However, when adiponectin (Ad was added in CIH + Ad group, we saw a rescue in the elevations of the aforementioned left ventricular function (p<0.05. To assess critical cardiac injury, we detected myocardial apoptosis by Terminal deoxynucleotidyl transfer-mediated dUTP nick end-labeling (TUNEL analysis. It was showed that the apoptosis percentage in CIH group (2.948% was significantly higher than that in NC group (0.4167% and CIH + Ad group (1.219% (p<0.05. Protein expressions of cleaved caspase-3, cleaved caspase-9, and cleaved-caspase-12 validated our TUNEL results (p<0.05. Mechanistically, our results demonstrated that the proteins expressed with endoplasmic reticulum stress and the expression of reactive oxygen species (ROS were significantly elevated under CIH conditions, whereas Ad supplementation partially decreased them. Overall, our results suggested that Ad augmentation could improve CIH

  7. Adiponectin protects the genioglossus of rats against chronic intermittent hypoxia-induced injury via inhibition of endoplasmic reticulum stress

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-feng; HUANG Han-peng; DING Wen-xiao; DING Ning; LU Gan; LIU Jian-nan; ZHANG Xi-long

    2013-01-01

    Background Obstructive sleep apnea hypopnea syndrome,characterized by chronic intermittent hypoxia (CIH),is closely correlated with genioglossus dysfunction.CIH has been identified to mediate mitochondrial damage in genioglossus.It has been reported that endoplasmic reticulum stress (ERS) could be induced by mitochondrial dysfunction.This study aimed to investigate the role of ERS in CIH-induced genioglossus injury,as well as the possible intervention effect of adiponectin (Ad) supplement in rats.Methods Forty-five male Wistar rats were randomly divided into three groups and submitted to room air (group A,n=15) as a control or CIH (groups B and C,n=15,respectively).Throughout the exposure period,intravenous Ad was given in group C; while intravenous normal saline was simultaneously given in groups A and B.After 35-day exposure,genioglossus samples were obtained from the pentobarbital-anaesthetized rats via surgical dissection,following blood sampling.Western blotting was applied to detect expressions of ERS signals and associated apoptotic pathways in genioglossus.Serum adiponectin levels were assessed via enzyme-linked immunosorbent assay (ELISA).Results Significant hypoadiponectinemia was revealed in group B only (P <0.05).Compared to those in groups A and C,expressions of markers involved in ERS,such as glucose regulated protein 78 (GRP78),p-PERK,phosphorylated eukaryotic initiation factor 2α (p-elF2α),phosphorylated inositol-requiring transmembrane kinase/endoribonuclease 1α (p-IRE1α),spliced X-Box binding protein 1 (XBP1s) and activating transcription factor 6 (ATF6),were significantly enhanced in group B (all P <0.01); while no significant difference was shown between groups A and C (all P >0.05).ERS-associated apoptotic pathways were remarkably activated in group B.The involved markers detected as the expression of CCAAT/enhancer binding protein homologous protein (CHOP),B-cell lymphoma/leukemia associatied X protein (BAX)and caspase-12 were

  8. Early life exposure to chronic intermittent Hypoxia Primes Increased Susceptibility to Hypoxia-Induced Weakness in Rat Sternohyoid Muscle during adulthood.

    LENUS (Irish Health Repository)

    McDonald, Fiona B

    2016-03-01

    Intermittent hypoxia is a feature of apnea of prematurity (AOP), chronic lung disease, and sleep apnea. Despite the clinical relevance, the long-term effects of hypoxic exposure in early life on respiratory control are not well defined. We recently reported that exposure to chronic intermittent hypoxia (CIH) during postnatal development (pCIH) causes upper airway muscle weakness in both sexes, which persists for several weeks. We sought to examine if there are persistent sex-dependent effects of pCIH on respiratory muscle function into adulthood and\\/or increased susceptibility to re-exposure to CIH in adulthood in animals previously exposed to CIH during postnatal development. We hypothesized that pCIH would cause long-lasting muscle impairment and increased susceptibility to subsequent hypoxia. Within 24 h of delivery, pups and their respective dams were exposed to CIH: 90 s of hypoxia reaching 5% O2 at nadir; once every 5 min, 8 h per day for 3 weeks. Sham groups were exposed to normoxia in parallel. Three groups were studied: sham; pCIH; and pCIH combined with adult CIH (p+aCIH), where a subset of the pCIH-exposed pups were re-exposed to the same CIH paradigm beginning at 13 weeks. Following gas exposures, sternohyoid and diaphragm muscle isometric contractile and endurance properties were examined ex vivo. There was no apparent lasting effect of pCIH on respiratory muscle function in adults. However, in both males and females, re-exposure to CIH in adulthood in pCIH-exposed animals caused sternohyoid (but not diaphragm) weakness. Exposure to this paradigm of CIH in adulthood alone had no effect on muscle function. Persistent susceptibility in pCIH-exposed airway dilator muscle to subsequent hypoxic insult may have implications for the control of airway patency in adult humans exposed to intermittent hypoxic stress during early life.

  9. Early Life Exposure to Chronic Intermittent Hypoxia Primes Increased Susceptibility to Hypoxia-Induced Weakness in Rat Sternohyoid Muscle During Adulthood

    Directory of Open Access Journals (Sweden)

    Fiona B Mcdonald

    2016-03-01

    Full Text Available Intermittent hypoxia is a feature of apnea of prematurity, chronic lung disease and sleep apnea. Despite the clinical relevance, the long-term effects of hypoxic exposure in early life on respiratory control are not well defined. We recently reported that exposure to chronic intermittent hypoxia (CIH during postnatal development (pCIH causes upper airway muscle weakness in both sexes, which persists for several weeks. We sought to examine if there are persistent sex-dependent effects of pCIH on respiratory muscle function into adulthood and/or increased susceptibility to re-exposure to CIH in adulthood in animals previously exposed to CIH during postnatal development. We hypothesized that pCIH would cause long-lasting muscle impairment and increased susceptibility to subsequent hypoxia. Within 24 hours of delivery, pups and their respective dams were exposed to CIH: 90s of hypoxia reaching 5% O2 at nadir; once every 5 min, 8 hrs per day for 3 weeks. Sham groups were exposed to normoxia in parallel. Three groups were studied: sham; pCIH; and pCIH combined with adult CIH (p+aCIH, where a subset of the pCIH-exposed pups were re-exposed to the same CIH paradigm beginning at 13 weeks. Following gas exposures, sternohyoid and diaphragm muscle isometric contractile and endurance properties were examined ex vivo. There was no apparent lasting effect of pCIH on respiratory muscle function in adults. However, in both males and females, re-exposure to CIH in adulthood in pCIH-exposed animals caused sternohyoid (but not diaphragm weakness. Exposure to this paradigm of CIH in adulthood alone had no effect on muscle function. Persistent susceptibility in pCIH-exposed airway dilator muscle to subsequent hypoxic insult may have implications for the control of airway patency in adult humans exposed to intermittent hypoxic stress during early life.

  10. The materno-fetal interface in llama (Lama guanicoe glama A interface materno-fetal em lhamas (Lama guanicoe glama

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    David M. Iturrizaga

    2007-06-01

    Full Text Available Samples from 9 llamas (28 through 36 weeks of gestation were collected and fixed in 4% buffered paraformaldehyde (light microscopy and in 2.5% buffered glutaraldehyde (transmission and scanning electron microscopy. The material was processed in paraplast and slides (5mm were stained with HE, PAS, Masson-Trichrome, acid phosphatase and Perl's. The uteroferrin was immunolocalized. The results show that llama placenta is chorioallantoic, diffuse, folded and epitheliochorial, and the fetus is covered with an epidermal membrane. The trophoblast cells have variable morphology: cubic, rounded and triangular cells, with cytoplasm containing PAS-positive granules. Binucleated cells with large cytoplasm and rounded nuclei, as well as giant trophoblastic cells with multiple nuclei were also observed. Numerous blood vessels were observed beneath the cells of the uterine epithelium and around the chorionic subdivided branches. Glandular activity was shown by PAS, Perl's, and acid phosphatase positive reactions in the cytoplasm and glandular lumen, and by immunolocalization of the uteroferrin in the glandular epithelium. The uterine glands open in spaces formed by the areoles, which are filled by PAS-positive material. The llama fetus was covered by the epidermal membrane, composed of stratified epithelium, with up to seven layers of mono-, bi- or trinucleated cells. The high level of maternal and fetal vascularization surfaces indicates an intense exchange of substances across both surfaces. The metabolic activity shown in the uterine glands suggests an adaptation of the gestation to the high altitudes of the natural habitat of this species.Fragmentos da placenta de 9 animais (28-36 semanas de gestação, provenientes do Instituto Veterinario de Investigaciones Tropicales y de Altura (IVITA, Cusco-Peru, e da Universidad del Altiplano (UNA, Puno-Peru, foram colhidos e fixados em paraformoldeído 4% em PBS para microscopia de luz e em glutaraldeido em 2,5% PBS para microscopia eletrônica de transmissão e de varredura. O material incluido em paraplast cortado com 5 mm foi processado para HE, PAS, Tricrômio de Masson, fosfatase ácida e Perl's e para imuno-histoquimica da uteroferrina. Os resultados mostraram que a placenta da lhama é corialantóide, difusa, pregueada e epiteliocorial e o feto está recoberto pela membrana epidermal. O trofoblasto possui morfologia variada: células cúbicas, arredondadas ou triangulares, com citoplasma contendo grânulos PAS+. Células binucleadas com citoplasma aumentado e núcleo arredondado e células trofoblásticas aumentados com múltiplos núcleos, também foram observadas. Grande quantidade de vasos sanguíneos foi observada entre as células do epitélio uterino e ao redor das projeções coriônicas, as quais estavam subdivididas. A atividade glandular foi demonstrada pelas reações de PAS, Perl's e fosfatase ácida positivas e pela imunolocalização da uteroferrina na luz e epitélio glandular. As glândulas uterinas abrem-se nos espaços formados pelas aréolas, as quais estavam preenchidas por material PAS+. Os fetos das lhamas estavam recobertos pela membrana epidermal, constituída por um epitélio estratificado composto por mais de 7 camadas de células mono, bi ou trinucleadas. A alta vascularização das superfícies materna e fetais indica intensa capacidade de trocas de substâncias entre as duas superfícies, e a atividade metabólica mostrada pelas glândulas uterinas sugere adaptação da gestação às altitudes elevadas do habitat natural desta espécie.

  11. Soluble Receptor for Advanced Glycation End Product Ameliorates Chronic Intermittent Hypoxia Induced Renal Injury, Inflammation, and Apoptosis via P38/JNK Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Xu Wu

    2016-01-01

    Full Text Available Obstructive sleep apnea (OSA associated chronic kidney disease is mainly caused by chronic intermittent hypoxia (CIH triggered tissue damage. Receptor for advanced glycation end product (RAGE and its ligand high mobility group box 1 (HMGB1 are expressed on renal cells and mediate inflammatory responses in OSA-related diseases. To determine their roles in CIH-induced renal injury, soluble RAGE (sRAGE, the RAGE neutralizing antibody, was intravenously administered in a CIH model. We also evaluated the effect of sRAGE on inflammation and apoptosis. Rats were divided into four groups: (1 normal air (NA, (2 CIH, (3 CIH+sRAGE, and (4 NA+sRAGE. Our results showed that CIH accelerated renal histological injury and upregulated RAGE-HMGB1 levels involving inflammatory (NF-κB, TNF-α, and IL-6, apoptotic (Bcl-2/Bax, and mitogen-activated protein kinases (phosphorylation of P38, ERK, and JNK signal transduction pathways, which were abolished by sRAGE but p-ERK. Furthermore, sRAGE ameliorated renal dysfunction by attenuating tubular endothelial apoptosis determined by immunofluorescence staining of CD31 and TUNEL. These findings suggested that RAGE-HMGB1 activated chronic inflammatory transduction cascades that contributed to the pathogenesis of the CIH-induced renal injury. Inhibition of RAGE ligand interaction by sRAGE provided a therapeutic potential for CIH-induced renal injury, inflammation, and apoptosis through P38 and JNK pathways.

  12. Immunoreactivity for neuronal NOS and fluorescent indication of NO formation in the NTS of juvenile rats submitted to chronic intermittent hypoxia.

    Science.gov (United States)

    Pajolla, Gisela P; Accorsi-Mendonça, Daniela; Lunardi, Claure N; Bendhack, Lusiane M; Machado, Benedito H; Llewellyn-Smith, Ida J

    2009-06-15

    Exposure to chronic intermittent hypoxia (CIH) leads to significant autonomic and respiratory changes, similar to those observed in obstructive sleep apnea. The hypertension associated with CIH is due to sympathoexcitation triggered by long-term exposure to intermittent hypoxia. However, the mechanisms underlying these effects are unknown. Changes in central regulation of sympathetic activity may underlie CIH-induced hypertension. Since NO appears to be mainly sympathoinhibitory in the nucleus of the solitary tract (NTS), we hypothesized that CIH augments sympathetic activity, in part by reducing neuronal nitric oxide synthase (nNOS) expression and consequently nitric oxide (NO) production in this brain region. To test our hypothesis, juvenile male Wistar rats were exposed to CIH for 8 h/day for 10 days and sections of perfused brainstem were either stained to reveal nNOS-immunoreactivity or loaded with DAF 2-DA to label neurons containing NO. CIH rats showed a significant increase in mean arterial pressure and heart rate compared to controls. However, there was no significant difference in the distribution, staining intensity or numbers of nNOS-immunoreactive neurons in the NTS between experimental and control rats. We also found no significant change in NO content in the DAF 2-DA-loaded sections of NTS from CIH rats. Our data show that NO is not altered in the NTS of juvenile CIH rats, suggesting that nitrergic mechanisms, at least in the NTS, are unlikely to be involved in the sympathetic excitation that generates the hypertension observed after 10 days of CIH.

  13. Distinct Effects of Nalmefene on Dopamine Uptake Rates and Kappa Opioid Receptor Activity in the Nucleus Accumbens Following Chronic Intermittent Ethanol Exposure

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    Jamie H. Rose

    2016-07-01

    Full Text Available The development of pharmacotherapeutics that reduce relapse to alcohol drinking in patients with alcohol dependence is of considerable research interest. Preclinical data support a role for nucleus accumbens (NAc κ opioid receptors (KOR in chronic intermittent ethanol (CIE exposure-induced increases in ethanol intake. Nalmefene, a high-affinity KOR partial agonist, reduces drinking in at-risk patients and relapse drinking in rodents, potentially due to its effects on NAc KORs. However, the effects of nalmefene on accumbal dopamine transmission and KOR function are poorly understood. We investigated the effects of nalmefene on dopamine transmission and KORs using fast scan cyclic voltammetry in NAc brain slices from male C57BL/6J mice following five weeks of CIE or air exposure. Nalmefene concentration-dependently reduced dopamine release similarly in air and CIE groups, suggesting that dynorphin tone may not be present in brain slices. Further, nalmefene attenuated dopamine uptake rates to a greater extent in brain slices from CIE-exposed mice, suggesting that dopamine transporter-KOR interactions may be fundamentally altered following CIE. Additionally, nalmefene reversed the dopamine-decreasing effects of a maximal concentration of a KOR agonist selectively in brain slices of CIE-exposed mice. It is possible that nalmefene may attenuate withdrawal-induced increases in ethanol consumption by modulation of dopamine transmission through KORs.

  14. Distinct Effects of Nalmefene on Dopamine Uptake Rates and Kappa Opioid Receptor Activity in the Nucleus Accumbens Following Chronic Intermittent Ethanol Exposure

    Science.gov (United States)

    Rose, Jamie H.; Karkhanis, Anushree N.; Steiniger-Brach, Björn; Jones, Sara R.

    2016-01-01

    The development of pharmacotherapeutics that reduce relapse to alcohol drinking in patients with alcohol dependence is of considerable research interest. Preclinical data support a role for nucleus accumbens (NAc) κ opioid receptors (KOR) in chronic intermittent ethanol (CIE) exposure-induced increases in ethanol intake. Nalmefene, a high-affinity KOR partial agonist, reduces drinking in at-risk patients and relapse drinking in rodents, potentially due to its effects on NAc KORs. However, the effects of nalmefene on accumbal dopamine transmission and KOR function are poorly understood. We investigated the effects of nalmefene on dopamine transmission and KORs using fast scan cyclic voltammetry in NAc brain slices from male C57BL/6J mice following five weeks of CIE or air exposure. Nalmefene concentration-dependently reduced dopamine release similarly in air and CIE groups, suggesting that dynorphin tone may not be present in brain slices. Further, nalmefene attenuated dopamine uptake rates to a greater extent in brain slices from CIE-exposed mice, suggesting that dopamine transporter-KOR interactions may be fundamentally altered following CIE. Additionally, nalmefene reversed the dopamine-decreasing effects of a maximal concentration of a KOR agonist selectively in brain slices of CIE-exposed mice. It is possible that nalmefene may attenuate withdrawal-induced increases in ethanol consumption by modulation of dopamine transmission through KORs. PMID:27472317

  15. Acute inhibition of glial cells in the NTS does not affect respiratory and sympathetic activities in rats exposed to chronic intermittent hypoxia.

    Science.gov (United States)

    Costa, Kauê M; Moraes, Davi J A; Machado, Benedito H

    2013-02-16

    Recent studies suggest that neuron-glia interactions are involved in multiple aspects of neuronal activity regulation. In the nucleus tractus solitarius (NTS) neuron-glia interactions are thought to participate in the integration of autonomic responses to physiological challenges. However, it remains to be shown whether NTS glial cells might influence breathing and cardiovascular control, and also if they could be integral to the autonomic and respiratory responses to hypoxic challenges. Here, we investigated whether NTS glia play a tonic role in the modulation of central respiratory and sympathetic activities as well as in the changes in respiratory-sympathetic coupling induced by exposure to chronic intermittent hypoxia (CIH), a model of central autonomic and respiratory plasticity. We show that bilateral microinjections of fluorocitrate (FCt), a glial cell inhibitor, into the caudal and intermediate subnuclei of the NTS did not alter baseline respiratory and sympathetic parameters in in situ preparations of juvenile rats. Similar results were observed in rats previously exposed to CIH. Likewise, CIH-induced changes in respiratory-sympathetic coupling were unaffected by FCt-mediated inhibition. However, microinjection of FCt into the ventral medulla produced changes in respiratory frequency. Our results show that acute glial inhibition in the NTS does not affect baseline respiratory and sympathetic control. Additionally, we conclude that NTS glial cells may not be necessary for the continuous manifestation of sympathetic and respiratory adaptations to CIH. Our work provides evidence that neuron-glia interactions in the NTS do not participate in baseline respiratory and sympathetic control.

  16. Time-Course Analysis of Brain Regional Expression Network Responses to Chronic Intermittent Ethanol and Withdrawal: Implications for Mechanisms Underlying Excessive Ethanol Consumption.

    Science.gov (United States)

    Smith, Maren L; Lopez, Marcelo F; Archer, Kellie J; Wolen, Aaron R; Becker, Howard C; Miles, Michael F

    2016-01-01

    Long lasting abusive consumption, dependence, and withdrawal are characteristic features of alcohol use disorders (AUD). Mechanistically, persistent changes in gene expression are hypothesized to contribute to brain adaptations leading to ethanol toxicity and AUD. We employed repeated chronic intermittent ethanol (CIE) exposure by vapor chamber as a mouse model to simulate the cycles of ethanol exposure and withdrawal commonly seen with AUD. This model has been shown to induce progressive ethanol consumption in rodents. Brain CIE-responsive expression networks were identified by microarray analysis across five regions of the mesolimbic dopamine system and extended amygdala with tissue harvested from 0-hours to 7-days following CIE. Weighted Gene Correlated Network Analysis (WGCNA) was used to identify gene networks over-represented for CIE-induced temporal expression changes across brain regions. Differential gene expression analysis showed that long-lasting gene regulation occurred 7-days after the final cycle of ethanol exposure only in prefrontal cortex (PFC) and hippocampus. Across all brain regions, however, ethanol-responsive expression changes occurred mainly within the first 8-hours after removal from ethanol. Bioinformatics analysis showed that neuroinflammatory responses were seen across multiple brain regions at early time-points, whereas co-expression modules related to neuroplasticity, chromatin remodeling, and neurodevelopment were seen at later time-points and in specific brain regions (PFC or HPC). In PFC a module containing Bdnf was identified as highly CIE responsive in a biphasic manner, with peak changes at 0 hours and 5 days following CIE, suggesting a possible role in mechanisms underlying long-term molecular and behavioral response to CIE. Bioinformatics analysis of this network and several other modules identified Let-7 family microRNAs as potential regulators of gene expression changes induced by CIE. Our results suggest a complex temporal

  17. Time-Course Analysis of Brain Regional Expression Network Responses to Chronic Intermittent Ethanol and Withdrawal: Implications for Mechanisms Underlying Excessive Ethanol Consumption.

    Directory of Open Access Journals (Sweden)

    Maren L Smith

    Full Text Available Long lasting abusive consumption, dependence, and withdrawal are characteristic features of alcohol use disorders (AUD. Mechanistically, persistent changes in gene expression are hypothesized to contribute to brain adaptations leading to ethanol toxicity and AUD. We employed repeated chronic intermittent ethanol (CIE exposure by vapor chamber as a mouse model to simulate the cycles of ethanol exposure and withdrawal commonly seen with AUD. This model has been shown to induce progressive ethanol consumption in rodents. Brain CIE-responsive expression networks were identified by microarray analysis across five regions of the mesolimbic dopamine system and extended amygdala with tissue harvested from 0-hours to 7-days following CIE. Weighted Gene Correlated Network Analysis (WGCNA was used to identify gene networks over-represented for CIE-induced temporal expression changes across brain regions. Differential gene expression analysis showed that long-lasting gene regulation occurred 7-days after the final cycle of ethanol exposure only in prefrontal cortex (PFC and hippocampus. Across all brain regions, however, ethanol-responsive expression changes occurred mainly within the first 8-hours after removal from ethanol. Bioinformatics analysis showed that neuroinflammatory responses were seen across multiple brain regions at early time-points, whereas co-expression modules related to neuroplasticity, chromatin remodeling, and neurodevelopment were seen at later time-points and in specific brain regions (PFC or HPC. In PFC a module containing Bdnf was identified as highly CIE responsive in a biphasic manner, with peak changes at 0 hours and 5 days following CIE, suggesting a possible role in mechanisms underlying long-term molecular and behavioral response to CIE. Bioinformatics analysis of this network and several other modules identified Let-7 family microRNAs as potential regulators of gene expression changes induced by CIE. Our results suggest a

  18. Time-Course Analysis of Brain Regional Expression Network Responses to Chronic Intermittent Ethanol and Withdrawal: Implications for Mechanisms Underlying Excessive Ethanol Consumption.

    Science.gov (United States)

    Smith, Maren L; Lopez, Marcelo F; Archer, Kellie J; Wolen, Aaron R; Becker, Howard C; Miles, Michael F

    2016-01-01

    Long lasting abusive consumption, dependence, and withdrawal are characteristic features of alcohol use disorders (AUD). Mechanistically, persistent changes in gene expression are hypothesized to contribute to brain adaptations leading to ethanol toxicity and AUD. We employed repeated chronic intermittent ethanol (CIE) exposure by vapor chamber as a mouse model to simulate the cycles of ethanol exposure and withdrawal commonly seen with AUD. This model has been shown to induce progressive ethanol consumption in rodents. Brain CIE-responsive expression networks were identified by microarray analysis across five regions of the mesolimbic dopamine system and extended amygdala with tissue harvested from 0-hours to 7-days following CIE. Weighted Gene Correlated Network Analysis (WGCNA) was used to identify gene networks over-represented for CIE-induced temporal expression changes across brain regions. Differential gene expression analysis showed that long-lasting gene regulation occurred 7-days after the final cycle of ethanol exposure only in prefrontal cortex (PFC) and hippocampus. Across all brain regions, however, ethanol-responsive expression changes occurred mainly within the first 8-hours after removal from ethanol. Bioinformatics analysis showed that neuroinflammatory responses were seen across multiple brain regions at early time-points, whereas co-expression modules related to neuroplasticity, chromatin remodeling, and neurodevelopment were seen at later time-points and in specific brain regions (PFC or HPC). In PFC a module containing Bdnf was identified as highly CIE responsive in a biphasic manner, with peak changes at 0 hours and 5 days following CIE, suggesting a possible role in mechanisms underlying long-term molecular and behavioral response to CIE. Bioinformatics analysis of this network and several other modules identified Let-7 family microRNAs as potential regulators of gene expression changes induced by CIE. Our results suggest a complex temporal

  19. Ang Ⅱ type 1 receptor expression in rat aorta exposed to chronic intermittent hypoxia: effects of p38MAPK and ERK1/2 signaling

    Institute of Scientific and Technical Information of China (English)

    SHANG Jin; YANG Yuan-yuan; GUO Xue-ling; LIU Hui-guo

    2013-01-01

    Background Obstructive sleep apnea is a frequent medical condition consisting of repetitive sleep-related episodes of upper air ways obstruction and can lead to hypertension.Ang Ⅱ type 1 receptor (AT1R) played important roles in hypertension since it binds with Ang Ⅱ,controlling salt-water and blood pressure homeostasis.This study explores rat aorta AT1R expression during intermittent hypoxia (IH) and the signaling pathways involved.Methods A rat model and a cell model used a BioSpherix-OxyCycler A84 system and a ProOx C21 system respectively.The arterial blood pressure was recorded by a Nihon Kohden Polygraph System.Immunohistochemic was used to focus and analyze the expression of AT1R in rat aorta.Real-time PCR and Western blotting were used to explore the signaling pathways that participated in AT1R expression.Results In this study,we found that chronic intermittent hypoxia (CIH) induced AT1R transcription which increased the blood pressure in rat aorta compared to normoxia and to sustained hypoxia.The AT1R protein expression in the aorta was similar to the real-time PCR results.We explored the signaling mechanisms involved in the AT1R induction in both rat aorta and the aortic endothelial cells by real-time PCR and Western blotting.Compared to normoxia,CIH increased ERK1 mRNA transcription but not ERK2 or p38MAPK in the aorta; whereas sustained hypoxia (SH) upregulated ERK2 but not ERK1 or p38MAPK mRNA.In cells,IH induced AT1R expression with ERK1/2 phosphorylation but reduced p38MAPKs phosphorylation,whereas SH induced only ERK1/2 phosphorylation.The ERK1/2 inhibitor PD98059 attenuated the IHinduced AT1R increase but the p38MAPK inhibitor SB203580 did not.Conclusions Our results indicate that CIH induced the elevation of rat blood pressure and aorta AT1R expression.Moreover,AT1R expression in IH and sustained hypoxia might be regulated by different signal transduction pathways,highlighting a novel regulatory function through ERK1/2 signaling in IH.

  20. Effect of chronic intermittent hypoxia on the expression of Nip3, cell apoptosis, β-amyloid protein deposit in mice brain cortex

    Institute of Scientific and Technical Information of China (English)

    ZENG Yi-ming; CAI Kai-jin; CHEN Xiao-yong; WU Minx-ia; LIN Xi

    2009-01-01

    Background Chronic intermittent hypoxia (CIH) is the most important pathophysiologic feature of sleep apnea syndrome (SAS). To explore the relationship between SAS and dementia, the effects of CIH on the expression of Nip3, neuron apoptosis andβ-amyloid protein deposit in the brain cortex of the frontal lobe of mice were evaluated in this study. Methods Thirty male ICR mice were divided into four groups: control group (A, n=-10, sham hypoxia/reoxygenation), 2 weeks CIH group (B, n=-5), 4 weeks CIH group (C, n=-5), and 8 weeks CIH group (D, n=10). The ICR mice were placed in a chamber and exposed to intermittent hypoxia (oxygen concentration changed periodically from (21.72±0.55)% to (6.84±0.47)% every two minutes, eight hours per day). Neuron apoptosis of the cortex of the frontal lobe was detected by means of terminal deoxy-nucleotidyl transferase-mediated in situ end labeling (TUNEL). Immunohistochemical staining was performed for measuring expression of Nip3 and β-amyloid protein. The ultrastructure of neurons was observed under a transmission electron microscope. Results TUNEL positive neurons in each square millimeter in the cortex of the frontal lobe were categorized by median or Ri into group A (1,5.5), group B (133, 13), group C (252, 21), and group D (318, 24). There were significant differences among the above four groups (P=0.000). The significance test was performed between the control group and each CIH group respectively: group A and B (P>0.05); group A and C (P 0.05); groups A and C (P<0.005); and groups A and D (P<0.005). There was no significant difference between groups B and C, groups B and D, and groups C and D. The expression of Nip3 was closely correlated with neuron apoptosis in the brain (P <0.05). The expression ofβ-amyloid protein in the brain of mice was negative in all CIH groups and the control group. Ultrastructure observation showed karyopyknosis of nucleus, swelling of chondriosomes, deposit of lipofuscins and degeneration of

  1. Ethanol withdrawal is required to produce persisting N-methyl-D-aspartate receptor-dependent hippocampal cytotoxicity during chronic intermittent ethanol exposure

    Science.gov (United States)

    Reynolds, Anna R.; Berry, B. Jennifer N.; Sharrett-Field, Lynda; Prendergast, Mark A.

    2015-01-01

    Chronic intermittent ethanol consumption is associated with neurodegeneration and cognitive deficits in preclinical laboratory animals and in the clinical population. While previous work suggests a role for neuroadaptations in the N-methyl-D-aspartate (NMDA) receptor in the development of ethanol dependence and manifestation of withdrawal, the relative roles of ethanol exposure and ethanol withdrawal in producing these effects have not been fully characterized. To examine underlying cytotoxic mechanisms associated with CIE exposure, organotypic hippocampal slices were exposed to 1–3 cycles of ethanol (50 mM) in cell culture medium for 5 days, followed by 24-hours of ethanol withdrawal in which a portion of slices were exposed to competitive NMDA receptor antagonist (2R)-amino-5-phosphonovaleric acid (APV; 40 µM). Cytotoxicity was assessed using immunohistochemical labeling of neuron specific nuclear protein (NeuN; Fox-3), a marker of mature neurons, and thionine (2%) staining of Nissl bodies. Multiple cycles of CIE produced neurotoxicity, as reflected in persisting losses of neuron NeuN immunoreactivity and thionine staining in each of the primary cell layers of the hippocampal formation. Hippocampi aged in vitro were significantly more sensitive to the toxic effects of multiple CIEs than were non-aged hippocampi. This effect was not demonstrated in slices exposed to continuous ethanol, in the absence of withdrawal, or to a single exposure/withdrawal regimen. Exposure to APV significantly attenuated the cytotoxicity observed in the primary cell layers of the hippocampus. The present findings suggest that ethanol withdrawal is required to produce NMDA receptor-dependent hippocampal cytotoxicity, particularly in the aging hippocampus in vitro. PMID:25746220

  2. Chronic intermittent hypoxia increases encoding pigment epithelium-derived factor gene expression, although not that of the protein itself, in the temporal cortex of rats*,**

    Science.gov (United States)

    Julian, Guilherme Silva; de Oliveira, Renato Watanabe; Favaro, Vanessa Manchim; de Oliveira, Maria Gabriela Menezes; Perry, Juliana Cini; Tufik, Sergio; Chagas, Jair Ribeiro

    2015-01-01

    Objective: Obstructive sleep apnea syndrome is mainly characterized by intermittent hypoxia (IH) during sleep, being associated with several complications. Exposure to IH is the most widely used animal model of sleep apnea, short-term IH exposure resulting in cognitive and neuronal impairment. Pigment epithelium-derived factor (PEDF) is a hypoxia-sensitive factor acting as a neurotrophic, neuroprotective, and antiangiogenic agent. Our study analyzed performance on learning and cognitive tasks, as well as PEDF gene expression and PEDF protein expression in specific brain structures, in rats exposed to long-term IH. Methods: Male Wistar rats were exposed to IH (oxygen concentrations of 21-5%) for 6 weeks-the chronic IH (CIH) group-or normoxia for 6 weeks-the control group. After CIH exposure, a group of rats were allowed to recover under normoxic conditions for 2 weeks (the CIH+N group). All rats underwent the Morris water maze test for learning and memory, PEDF gene expression and PEDF protein expression in the hippocampus, frontal cortex, and temporal cortex being subsequently assessed. Results: The CIH and CIH+N groups showed increased PEDF gene expression in the temporal cortex, PEDF protein expression remaining unaltered. PEDF gene expression and PEDF protein expression remained unaltered in the frontal cortex and hippocampus. Long-term exposure to IH did not affect cognitive function. Conclusions: Long-term exposure to IH selectively increases PEDF gene expression at the transcriptional level, although only in the temporal cortex. This increase is probably a protective mechanism against IH-induced injury. PMID:25750673

  3. Chronic intermittent hypobaric hypoxia protects the heart against ischemia/reperfusion injury through upregulation of antioxidant enzymes in adult guinea pigs

    Institute of Scientific and Technical Information of China (English)

    Hui-cai GUO; Zhe ZHANG; Li-nan ZHANG; Chen XIONG; Chen FENG; Qian LIU; Xu LIU; Xiao-lu SHI; Yong-li WANG

    2009-01-01

    Aim:To investigate the protection and the anti-oxidative mechanism afforded by chronic intermittent hypobaric hypoxia (CIHH) against ischemia/reperfusion (I/R) injury in guinea pig hearts.Methods:Adult male guinea pigs were exposed to CIHH by mimicking a 5000 m high altitude (pB=404 mmHg,p02=84 mmHg) in a hypobaric chamber for 6 h/day for 28 days.Langendorff-perfused isolated guinea pig hearts were used to measure variables of left ventricular function during baseline perfusion,ischemia and the reperfusion period.The activity and protein expression of antioxidant enzymes in the left myocardium were evaluated using biochemical methods and Western blotting.respectively.Intracellular reactive oxygen species (ROS) were assessed using ROS-sensitive fluorescence.Results:After 30 min of global no-flow ischemia followed by 60 min of reperfusion,myocardial function had better recovery rates in CIHH guinea pig hearts than in control hearts.The activity and protein expression of superoxide dismutase (SOD) and catalase (CAT) were significantly increased in the myocardium of CIHH guinea pigs.Pretreatment of control hearts with an antioxidant mixture containing SOD and CAT exerted cardioprotective effects similar to CIHH.The irreversible CAT inhibitor aminotriazole (ATZ) abolished the cardioprotection of CIHH.Cardiac contractile dysfunction and oxidative stress induced by exogenous hydrogen peroxide (H2O2) were attenuated by CIHH and CAT.Conclusions:These data suggest that CIHH protects the heart against I/R injury through upregulation of antioxidant enzymes in guinea pig.

  4. Long-term effects of chronic intermittent ethanol exposure in adolescent and adult rats: radial-arm maze performance and operant food reinforced responding.

    Directory of Open Access Journals (Sweden)

    Mary-Louise Risher

    Full Text Available Adolescence is not only a critical period of late-stage neurological development in humans, but is also a period in which ethanol consumption is often at its highest. Given the prevalence of ethanol use during this vulnerable developmental period we assessed the long-term effects of chronic intermittent ethanol (CIE exposure during adolescence, compared to adulthood, on performance in the radial-arm maze (RAM and operant food-reinforced responding in male rats.Male Sprague Dawley rats were exposed to CIE (or saline and then allowed to recover. Animals were then trained in either the RAM task or an operant task using fixed- and progressive- ratio schedules. After baseline testing was completed all animals received an acute ethanol challenge while blood ethanol levels (BECs were monitored in a subset of animals. CIE exposure during adolescence, but not adulthood decreased the amount of time that animals spent in the open portions of the RAM arms (reminiscent of deficits in risk-reward integration and rendered animals more susceptible to the acute effects of an ethanol challenge on working memory tasks. The operant food reinforced task showed that these effects were not due to altered food motivation or to differential sensitivity to the nonspecific performance-disrupting effects of ethanol. However, CIE pre-treated animals had lower BEC levels than controls during the acute ethanol challenges indicating persistent pharmacokinetic tolerance to ethanol after the CIE treatment. There was little evidence of enduring effects of CIE alone on traditional measures of spatial and working memory.These effects indicate that adolescence is a time of selective vulnerability to the long-term effects of repeated ethanol exposure on neurobehavioral function and acute ethanol sensitivity. The positive and negative findings reported here help to further define the nature and extent of the impairments observed after adolescent CIE and provide direction for future

  5. Chronic intermittent hypoxia increases encoding pigment epithelium-derived factor gene expression, although not that of the protein itself, in the temporal cortex of rats,

    Directory of Open Access Journals (Sweden)

    Guilherme Silva Julian

    2015-02-01

    Full Text Available Objective: Obstructive sleep apnea syndrome is mainly characterized by intermittent hypoxia (IH during sleep, being associated with several complications. Exposure to IH is the most widely used animal model of sleep apnea, short-term IH exposure resulting in cognitive and neuronal impairment. Pigment epithelium-derived factor (PEDF is a hypoxia-sensitive factor acting as a neurotrophic, neuroprotective, and antiangiogenic agent. Our study analyzed performance on learning and cognitive tasks, as well as PEDF gene expression and PEDF protein expression in specific brain structures, in rats exposed to long-term IH. Methods: Male Wistar rats were exposed to IH (oxygen concentrations of 21-5% for 6 weeks-the chronic IH (CIH group-or normoxia for 6 weeks-the control group. After CIH exposure, a group of rats were allowed to recover under normoxic conditions for 2 weeks (the CIH+N group. All rats underwent the Morris water maze test for learning and memory, PEDF gene expression and PEDF protein expression in the hippocampus, frontal cortex, and temporal cortex being subsequently assessed. Results: The CIH and CIH+N groups showed increased PEDF gene expression in the temporal cortex, PEDF protein expression remaining unaltered. PEDF gene expression and PEDF protein expression remained unaltered in the frontal cortex and hippocampus. Long-term exposure to IH did not affect cognitive function. Conclusions: Long-term exposure to IH selectively increases PEDF gene expression at the transcriptional level, although only in the temporal cortex. This increase is probably a protective mechanism against IH-induced injury.

  6. Altered Wnt Signaling Pathway in Cognitive Impairment Caused by Chronic Intermittent Hypoxia: Focus on Glycogen Synthase Kinase-3β and β-catenin

    Institute of Scientific and Technical Information of China (English)

    Yue-Ying Pan; Yan Deng; Sheng Xie; Zhi-Hua Wang; Yu Wang; Jie Ren; Hui-Guo Liu

    2016-01-01

    Background:Cognitive impairment is a severe complication caused by obstructive sleep apnea (OSA).The mechanisms of causation are still unclear.The Wnt/β-catenin signaling pathway is involved in cognition,and abnormalities in it are implicated in neurological disorders.Here,we explored the Wnt/β-catenin signaling pathway abnormalities caused by chronic intermittent hypoxia (CIH),the most characteristic pathophysiological component of OSA.Methods:We divided 32 4-week-old male C57/BL mice into four groups of eight each:a CIH + normal saline (NS) group,CIH + LiC1 group,sham CIH + NS group,and a sham CIH + LiC1 group.The spatial learning performance of each group was assessed by using the Morris water maze (MWM).Protein expressions of glycogen synthase kinase-3β (GSK-3β) and β-catenin in the hippocampus were examined using the Western blotting test.EdU labeling and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining methods were used,respectively,to determine the proliferation and apoptosis of neurons in the hippocampal dentate gyrus region.Results:Mice exposed to CIH showed impaired spatial learning performance in the MWM,including increased mean escape latencies to reach the target platform,decreased mean times passing through the target platform and mean duration in the target quadrant.The GSK-3β activity increased,and expression of β-catenin decreased significantly in the hippocampus of the CIH-exposed mice.Besides,CIH significantly increased hippocampal neuronal apoptosis,with an elevated apoptosis index.Meanwhile,LiCl decreased the activity of GSK-3β and increased the expression of β-catenin and partially reversed the spatial memory deficits in MWM and the apoptosis caused by CIH.Conclusions:Wnt/β-catenin signaling pathway abnormalities possibly play an important role in the development of cognitive deficits among mice exposed to CIH and that LiCl might attenuate CIH-induced cognitive impairment via Wnt

  7. Intermittent Oxygen Inhalation with Proper Frequency Improves Overall Health Conditions and Alleviates Symptoms in a Population at High Risk of Chronic Mountain Sickness with Severe Symptoms

    Institute of Scientific and Technical Information of China (English)

    Bin Feng; Wei-Hao Xu; Yu-Qi Gao; Fu-Yu Liu; Peng Li; Shan-Jun Zheng; Lu-Yue Gai

    2016-01-01

    Background:Oxygen inhalation therapy is essential for the treatment of patients with chronic mountain sickness (CMS),but the efficacy of oxygen inhalation for populations at high risk of CMS remains unknown.This research investigated whether oxygen inhalation therapy benefits populations at high risk of CMS.Methods:A total of 296 local residents living at an altitude of 3658 m were included;of which these were 25 diagnosed cases of CMS,8 cases dropped out of the study,and 263 cases were included in the analysis.The subjects were divided into high-risk (180 ≤ hemoglobin (Hb) <210 g/L,n =161) and low-risk (Hb <180 g/L,n =102) groups,and the cases in each group were divided into severe symptom (CMS score ≥6) and mild symptom (CMS score 0-5) subgroups.Severe symptomatic population of either high-or low-risk CMS was randomly assigned to no oxygen intake group (A group) or oxygen intake 7 times/week group (D group);mild symptomatic population of either high-or low-risk CMS was randomly assigned to no oxygen intake group (A group),oxygen intake 2 times/week group (B group),and 4 times/week group (C group).The courses for oxygen intake were all 30 days.The CMS symptoms,sleep quality,physiological biomarkers,biochemical markers,etc.,were recorded on the day before oxygen intake,on the 15th and 30th days of oxygen intake,and on the 15th day after terminating oxygen intake therapy.Results:A total of 263 residents were finally included in the analysis.Among these high-altitude residents,CMS symptom scores decreased for oxygen inhalation methods B,C,and D at 15 and 30 days after oxygen intake and 15 days after termination,including dyspnea,palpitation,and headache index,compared to those before oxygen intake (B group:Z =5.604,5.092,5.741;C group:Z =4.155,4.068,4.809;D group:Z =6.021,6.196,5.331,at the 3 time points respectively;all P < 0.05/3 vs.before intake).However,dyspnea/palpitation (A group:Z =5.003,5.428,5.493,both P < 0.05/3 vs.before intake) and headache (A

  8. 慢性间断性缺氧伴二氧化碳潴留小鼠模型的建立%A Mice Mode of Chronic Intermittent Hypoxia with Carbon Dioxide Retention

    Institute of Scientific and Technical Information of China (English)

    刘海林; 张子彦; 郭云云; 李景春; 宋永斌; 徐江涛

    2012-01-01

    目的 建立慢性间断性缺氧伴二氧化碳潴留(chronic intermittent hypoxia with carbon dioxide retention,CIH-CR)小鼠模型.方法 选取雄性昆明小鼠22只,随机分为常氧组(normal control group,NC)和CIH-CR组,每组11只.CIH-CR组小鼠每天CIH-CR处理8h,共4周,实验期间监测箱内O2和CO2浓度及小鼠尾部末端血氧饱和度( SO2).实验终点测定右室肥厚指数并观察心、肺、肾、脑组织病理改变.结果 CIH-CR组箱内O2浓度、CO2浓度和小鼠尾部末端SO2随实验仓的关闭和开启出现周期性的变化;与NC组相比CIH-CR组右心室明显肥大(P<0.01);小鼠心、肺、肾和脑组织均出现明显缺氧改变.结论 成功建立了CIH-CR小鼠模型.%Objective To establish a chronic intermittent hypoxia with carbon dioxide retention (CIH-CR)model in mice. Methods 22 male Kun Ming mice were divided into the normal control (NC) group and CIH-CR group. The mice of CIH-CR group suffered 8 hours intermittent hypoxia everyday for 4 weeks. The concentration of O2 and CO2 in the cabin was detected by oxygen analyzer and Carbon dioxide detector, meanwhile, the blood oxygen saturation were detected by blood oximeter. At the end of the experiment, weight of right and left ventricles was measured. The general pathological changes of myocardium, pulmonary, kidney and brain were observed by HE staining. Result The concentration of O2 and CO2 in the cabin and the SO2in the empennage of mouse accord with the cyclical change process. Compared with the NC group, the right ventricular hypertrophy were increased in the CIH-CR groups ( P < 0. 01 ). The tissue of myocardium, pulmonary, kidney and brain were showen obvious hypoxic change in CIH-CR group. Conclusion A CIH-CR animal model were be established successfully.

  9. INTERMITTENT DEGRADATION AND SCHIZOTYPY

    OpenAIRE

    Roché, Matthew W.; Silverstein, Steven M.; Lenzenweger, Mark F.

    2015-01-01

    Intermittent degradation refers to transient detrimental disruptions in task performance. This phenomenon has been repeatedly observed in the performance data of patients with schizophrenia. Whether intermittent degradation is a feature of the liability for schizophrenia (i.e., schizotypy) is an open question. Further, the specificity of intermittent degradation to schizotypy has yet to be investigated. To address these questions, 92 undergraduate participants completed a battery of self-repo...

  10. Chronic shifts in the length and phase of the light cycle increase intermittent alcohol drinking in C57BL/6J mice

    Directory of Open Access Journals (Sweden)

    Danielle eGulick

    2015-02-01

    Full Text Available Introduction: Shift workers – e.g., health care professionals, truck drivers, and factory workers – are forced to maintain daily cycles at odds with their natural circadian rhythms and as a consequence need to frequently readjust these cycles. This shift work-induced circadian desynchrony (CD is associated with increased sleep disorders and with alcohol abuse. Nonetheless, it has proven difficult to model CD-induced changes in alcohol consumption in mouse models, which is an important step toward identifying the mechanisms by which CD increases alcohol intake. This study examined whether frequent changes in the light cycle could increase free access alcohol intake in a mouse line that readily consumes alcohol. Methods: Free access alcohol intake, water intake, and wheel-running activity patterns of male C57BL/6J mice were measured while the mice were maintained on a normal 12HR photoperiod for baseline data for two weeks. The mice were then exposed to an alternating photoperiod of 12 hours and 18 hours, with light onset advanced 8 hours during the 18HR photoperiod. The photoperiods rotated every three days, for 21 days total. Results: The repeated pattern of phase advances and delays, with a concurrent change in the length of the photoperiod, shifted mice to a pattern of bingeintermittent drinking alcoholalcohol drinking without altering water intake. Wheel running activity demonstrated that mice were unable to reset their behavioral clocks during CD, showing constant, low-level activity with no peak in activity at the start of the dark phase and greater activity during the morning light phase. Conclusion: It is possible to model CD effects on alcohol intake in C57BL/6J mice using a pattern of phase shifts and changes in the photoperiod. Using this model, we demonstrate that mice begin intermittent drinking during CD, and this increase in alcohol intake does not correlate with an increase in overall activity or in overall fluid intake.

  11. Intermittent Explosive Disorder

    Directory of Open Access Journals (Sweden)

    Lut Tamam

    2011-09-01

    Full Text Available Intermittent explosive disorder is an impulse control disorder characterized by the occurrence of discrete episodes of failure to resist aggressive impulses that result in violent assault or destruction of property. Though the prevalence intermittent explosive disorder has been reported to be relatively rare in frontier studies on the field, it is now common opinion that intermittent explosive disorder is far more common than previously thought especially in clinical psychiatry settings. Etiological studies displayed the role of both psychosocial factors like childhood traumas and biological factors like dysfunctional neurotransmitter systems and genetics. In differential diagnosis of the disorder, disorders involving agression as a symptom such as alcohol and drug intoxication, antisocial and borderline personality disorders, personality changes due to general medical conditions and behavioral disorder should be considered. A combination of pharmacological and psychotherapeutic approaches are suggested in the treatment of the disorder. This article briefly reviews the historical background, diagnostic criteria, epidemiology, etiology and treatment of intermittent explosive disorder.

  12. Intermittency in particle physics

    International Nuclear Information System (INIS)

    This thesis presents an analysis of intermittency as it appears in high energy multiparticle production. Momentum space particle distributions are scale invariant and fluctuate from events to events. This phenomenon originates from Hydrodynamics. Some results about hydrodynamics intermittency are by the way deduced using random diffusion processes and the Landau-Ginzburg equation. A phenomenological approach utilizing random cascading models is used to describe the morphology and intermittent features of particle distributions. Along these lines, a thorough study of random cascades is performed. The origin of intermittent fluctuation is to be found within the Framework of Quantum Field Theory. Indeed intermittency is intimately linked to the perturbative cascade of Quantum Chromodynamics. The long distance behaviour of perturbative QCD is intermittent at the leading collinear logarithm approximation. Moreover fluctuations of matter density along the rapidity axis suggest that the gluon cascade undergoes a phase transition towards a valley landscape where gluons are prone to get clumped within small regions. This is compatible with the so-called preconfinement

  13. [Materno-fetal acid-base equilibrium evaluation in parturients submitted to ketamine anesthesia (author's transl)].

    Science.gov (United States)

    Mauad Filho, F; Meirelles, R S

    1975-01-01

    In the present work ketamine was used as anesthetic during the labor in order to evaluate the effect of this anesthetic on the binominal fetus-mother. Two groups of parturients and their fetuses, were studied: 1) The experimental group, with 22 parturients and their fetuses submitted to ketamine anesthesia during the labord, and 2) The control group, with 20 parturients and their fetuses without any analgesic treatment during the labor. In 20 cases of the experimental group the anesthetic was injected during the delivery labor and the other two just before it. It were evaluated in the mother's blood the biochemical parameters of the acid-base balance and others collateral effects of the anesthesia; on the fetus's side the same parameters also and the cardiac frequency. The newborn were evaluated by Apgar Score during the first and fifth minutes of life. The incidence of the spontaneous delivery in the experimental group, was 78%; in 22% of these patients the forceps of relief was used. In 22 cases in which Ketamine was applied it were observed, the following events: elevation of the blood pressure (50%), perineum rigidness (18%), dreams and or hallucinations (18%), increase of the cardiac frequency (9%), apneia (4%) and nausea (4%). It was also observed an increase of uterine tonus an abolishment of abdominal press during the delivery labor, studied through the uterine electromyography register. It was noted after the Ketamine application a fall in the pH of the maternal peripherical venous blood, fetal skull blood and the pH of the blood of the umbilical vein. 22% of the newborns, from the experimental group, presented a depression in the first minute of life (Apgar less than or equals to 6). The pCO2 values in the blood of the umbilical artery were higher in the experimental group than in the control one. PMID:1241148

  14. Effect of endoplasmic reticulum stress on brain injury following chronic intermittent hypoxia in growing rats%内质网应激在慢性间歇低氧幼鼠脑损害中的作用

    Institute of Scientific and Technical Information of China (English)

    李秀翠; 方励; 李志洁; POONITNehaDevi; 陈帆; 蔡晓红

    2016-01-01

    AIM:To explore the role of endoplasmic reticulum stress ( ERS) in brain injury following chronic intermittent hypoxia in growing rats and the protective effect of treatment with salubrinal .METHODS: Healthy male SD rats (3~4-week-old, 100~120 g, n=64) were randomly assigned to 8 groups (8 rats in each group):the groups of in-termittent hypoxia for 2 and 4 weeks (2IH and 4IH), the groups of control (C) for 2 and 4 weeks (2C and 4C), the groups of dimethylsulfoxide (DMSO) for 2 and 4 weeks (2DMSO and 4DMSO) and the groups of salubrinal for 2 and 4 weeks (2SAL and 4SAL).The 8-arm radial maze was used to assess the working memory error (WME), reference memory error (RME) and total error (TE) of the rats.The changes of neuronal apoptosis in the hippocampus were observed by ter -minal deoxynucleotidyl transferase dUTP nick end labeling ( TUNEL ) staining.The activity of superoxide dismutase (SOD), and the protein levels of endoplasmic reticulum stress marker compounds , C/EBP homologous protein (CHOP), phosphorylated eukaryotic translation initiation factor 2 alpha ( p-eIF2α) and phosphorylated protein kinase R-like endo-plasmic reticulum kinase (p-PERK), were analyzed.RESULTS: Chronic intermittent hypoxia (CIH) significantly in-creased RME, WME, TE and neuronal apoptotic index (AI) (P<0.01), and decreased the activity of SOD in the hippo-campus and serum (P<0.01).The protein levels of p-PERK and CHOP progressively increased in hippocampus in IH groups (P<0.01), and p-eIF2αwas downregulated (P<0.05).Treatment with salubrinal significantly decreased RME (P<0.05), WME (P<0.05), TE (P<0.01) and AI (P<0.01), and increased the activity of SOD (P<0.01).Sa-lubrinal induced the phosphorylation of eIF 2αsignificantly after CIH in hippocampus and downregulated the level of CHOP (P<0.01).CONCLUSION: Chronic intermittent hypoxia upregulates the protein levels of p-PERK and CHOP in the hippocampus , and decreases p-eIF2αprotein and the activity of SOD .Salubrinal , a selective

  15. The role of Foxp3+T cells in chronic intermittent hypoxia induced liver injury%Foxp3+Tregs在慢性间歇低氧所致肝损伤中的作用

    Institute of Scientific and Technical Information of China (English)

    白晓纯; 王琳; 赵忺; 田建立

    2016-01-01

    Objective To explore the role of Foxp3+ T cells (Tregs) in liver injury induced by chronic intermittent hypoxia. Methods Thirty-two male Wister rats were divided into four groups:control group (A), high-fat diet group (B), intermittent hypoxia group (C), and high-fat diet and intermittent hypoxia group (D). After 4 weeks, blood samples were collected and livers were surgically removed. Using the standard automatic clinical analyzer to test serum levels of total cholesterol (TC), low density lipoprotein cholesterol (LDL- C), alanina aminotransferase (ALT) and aspartato aminotransferase (AST). The MDA content of liver tissue was measured by colorimetrc method. The levels of TNF-αand IL-1βwere measured by radiommunoassay, and the expression of Foxp3 protein was measured by Western blotting technique. Results Serum levels of TC and LDL-C were significantly higher in B group than those of A, C and D groups, and which were higher in D group than those of A and C groups (P<0.05). There were no significant differences in serum levels of TC and LDL-C between A group and C group. Serum levels of ALT, AST, MDA, TNF-αand IL-1βwere significantly higher in C group than those of A group, and which were significantly higher in D group than those of A, B and C groups (P<0.05). There were no significant differences in these indicators between A group and B group, and between B group and C group. Foxp3 protein expression in liver was significantly lower in D group than that of other groups (P<0.05). Conclusion Foxp3+T regulatory cells involve in the regulation of hepatic injury induced by chronic intermittent hypoxia on the basis of a high-fat diet, and which may play an important role in this process of protective immune response.%目的:探讨叉头样转录因子P3(Foxp3)阳性调节性T细胞(Tregs)在慢性间歇低氧诱导的肝损伤中的作用。方法32只雄性Wistar大鼠随机均分为空白对照组(A组)、高脂饮食组(B组)、间歇低氧组

  16. 慢性间断性缺氧对帕金森病模型小鼠认知功能的影响%Effect of chronic intermittent hypoxia on the cognitive function of mouse model for Parkinson's disease

    Institute of Scientific and Technical Information of China (English)

    刘海林; 徐江涛; 宋永斌; 杨俊; 许永华; 余伍忠; 李景春; 张子彦

    2011-01-01

    Objective: To investigate the effect of chronic intermittent hypoxia on cognitive function in the mouse model of Parkinsons disease.Methods: Forty-four six-week-old male C57BL/6 mice were randomly divided into Paraquat (PQ) group, chronic intermittent hypoxia (CIH) group, PQ + CIH group and control group.Hypoxia-reoxygen device simulates the process of CIH.Meanwhile, intraperitoneal injection of PQ induced the mouse model of Parkinson's disease.Learning and memory function were evaluated by Y-type maze and step-down test.Acetylcholine (Ach) level and acetyl cholinesterase (Ach E) activity in hippocampus of mice were detected by colorimetric method.Results: Comparing with PQ group, PQ + CIH group had an extended total reaction time (TRT) (F <0.01) and an increased error number (EN) (P <0.05) of learning and memory both in Y-type maze test and step-down test.Comparing with PQ group, the Ach level and Ach E activity of mice hippocampus in PQ + CIH group were significantly decreased ( P < 0.05 ).Conclusion: CIH increased the degree of cognition decline in PQ induced mouse model of PD, which may be related with the decrease of Ach level and Ach E activity in hippocampus.%目的:探讨慢性间断性缺氧(CIH)对帕金森病模型小鼠认知功能的影响.方法:44只雄性6周龄C57BL/6小鼠,随机分为百草枯组、CIH组、百草枯加CIH组和对照组.用缺氧-复氧循环装置模拟 CIH 过程,通过腹腔注射百草枯诱导制备帕金森病模型小鼠.使用Y型-电迷宫和跳台实验评价小鼠学习记忆能力;化学比色法测定小鼠海马乙酰胆碱含量和乙酰胆碱酯酶活性.结果:3个实验组的学习记忆成绩、乙酰胆碱含量和乙酰胆碱酯酶活性均明显低于对照组(P均<0.01),其中百草枯加CIH组明显低于百草枯组与CIH组(P均<0.05),百草枯组与CIH组比较差异无统计学意义(P均>0.05).结论:CIH加重了百草枯所致帕金森病模型小鼠认知功能下降程度,可

  17. Relationship between nocturnal chronic intermittent hypoxia and fatty liver in hypertensive patients%夜间间歇性低血氧与高血压患者脂肪肝的关系

    Institute of Scientific and Technical Information of China (English)

    邵亮; 李南方; 姚晓光; 洪静; 周克明

    2013-01-01

    Objective To investigate the relationship between nocturnal chronic intermittent hypoxia and fatty liver in hypertensive patients.Methods 168 patients with hypertension who underwent both polysomnography and liver ultrasonography were enrolled from July 2004 to March 2006.The main clinical features as well as apneahypnea index(AHI) and the lowest oxygen saturation (LSaO2),were compared between patients with and without fatty liver,and the potential risk factors of fatty liver were discussed.Results 101 out of 168 cases were diagnosed as fatty liver,in which the body mass index,fasting blood glucose,triglyceride,alanine aminotransferase (ALT),aspartate amino-transferase(AST),Gamma-glutamyl transpeptidase(GGT) and mean AHI were significantly higher,while the LSaO2 [(79.37 + 9.19) % vs.(83.12 + 6.40) %,P < 0.05] was much lower compared with patients without fatty liver.The multivariate logistic regression indicated that the fasting blood glucose [OR (95% CI):3.794 (1.678-8.578)],LSaO2 [OR (95% CI):3.378 (1.464-7.796)] were possible contributing risk factors of fatty liver in patients with hypertension.Conclusion Nocturnal chronic intermittent hypoxia may play a role in the pathogenesis of fatty liver disease in hypertensive patients.%目的 探讨高血压患者夜间间歇性低血氧与脂肪肝的关系.方法 选择行多导睡眠监测的原发性高血压患者168例,并根据肝脏超声影像学的诊断结果分组,比较两组间临床、实验室资料及多导睡眠监测指标中的睡眠呼吸暂停低通气指数(AHI)、最低血氧饱和度(LSaO2),分析脂肪肝形成的相关因素.结果 脂肪肝组(101例)较非脂肪肝组(67例)的体重指数、空腹血糖、甘油三酯、丙氨酸氨基转移酶、门冬氨酸氨基转移酶、谷酰转肽酶明显增高(P<0.05),但LSaO2水平明显降低[(79.37±9.19)% vs.(83.12±6.40)%,P<0.05].Logistic回归分析表明空腹血糖、LSaO2可能是高血压患者脂肪肝的形成

  18. The study of genistein attenuating genioglossus muscle fatigue under chronic intermittent hypoxia%金雀异黄素减弱慢性间歇性低氧大鼠颏舌肌疲劳的实验研究

    Institute of Scientific and Technical Information of China (English)

    丁王辉; 李文; 陈小燕; 施洁珺

    2016-01-01

    目的 探讨金雀异黄素对慢性间歇性低氧(chronic intermittent hypoxia,CIH)大鼠颏舌肌功能及核因子-E2相关因子(nuclear factor erythroid 2 related factor 2,Nrf-2)/抗氧化反应元件(antioxidant responsive element, ARE)信号通路的影响,以期找到药物治疗阻塞性睡眠呼吸暂停低通气综合征的方法.方法 8周龄健康雌性SD大鼠30只,去势1周后用随机数字表法分为对照组、CIH组(低氧组)、CIH+金雀异黄素治疗组(治疗组),每组10只.后两组建立CIH动物模型(8 h/d,5周).电生理法检测并计算大鼠颏舌肌强直收缩20、40、60、80和100s时抗疲劳性,实时定量反转录PCR及蛋白质印迹法检测Nrf-2基因及蛋白表达.结果 与对照组相比,低氧组大鼠各时间点颏舌肌抗疲劳性显著降低(P<0.05);与低氧组相比,治疗组颏舌肌各时间点抗疲劳性显著增强(P<0.05),但仍显著小于对照组(P<0.05).低氧组大鼠颏舌肌Nrf-2基因及蛋白表达(0.54±0.11和0.35±0.13)显著低于对照组(1.00±0.00和1.00±0.00) (P<0.05),治疗组Nrf-2基因及蛋白表达(0.76±0.16和0.63±0.14)相对低氧组上调(P<0.05),但仍显著低于对照组(P<0.05).结论 CIH通过抑制Nrf-2/ARE信号通路降低大鼠颏舌肌的抗疲劳能力,金雀异黄素通过增强Nrf-2基因及蛋白表达发挥对颏舌肌的保护作用.%Objective To investigate the effects of genistein on genioglossus muscle function and nuclear factor erythroid 2 related factor 2(Nrf-2)/antioxidant responsive element(ARE) signaling pathway in rats under chronic intermittent hypoxia(CIH) condition in order to find medication treatment of obstructive sleep apnea/hyponea syndrome.Methods Thirty female Sprague-Dawley(SD) rats (8 weeks old) were randomly(random number table) divided into three groups 1 week after ovariectomy: control group(NC group), CIH group, and CIH+genistein treatment group(T group).Rats in the latter two groups were exposed to CIH for 8 h/d for 5

  19. Chronic intermittent ethanol exposure alters stress effects on (3α,5α-3-hydroxy-pregnan-20-one (3α,5α-THP immunolabeling of amygdala neurons in C57BL/6J mice

    Directory of Open Access Journals (Sweden)

    Antoniette M Maldonado-Devincci

    2016-03-01

    Full Text Available The GABAergic neuroactive steroid (3α,5α-3-hydroxy-pregnan-20-one (3α,5α-THP, allopregnanolone is decreased in various brain regions of C57BL/6J mice following exposure to an acute stressor or chronic intermittent ethanol (CIE exposure and withdrawal. It is well established that there are complex interactions between stress and ethanol drinking, with mixed literature regarding the effects of stress on ethanol intake. However, there is little research examining how chronic ethanol exposure alters stress responses. The present work examined the impact of CIE exposure and withdrawal on changes in brain levels of 3α,5α-THP, hormonal, and behavioral responses to forced swim stress (FSS. Adult male C57BL/6J mice were exposed to four cycles of CIE to induce ethanol dependence. Following 8 or 72 hr withdrawal, mice were subjected to FSS for 10 min, and 50 min later brains were collected for immunohistochemical analysis of cellular 3α,5α-THP. Behavioral and circulating corticosterone responses to the FSS were quantified. Following 8 hr withdrawal, ethanol exposure potentiated the corticosterone response to FSS. Following 72 hr withdrawal, this difference was no longer observed. Following 8 hr withdrawal, stress-exposed mice showed no differences in immobility, swimming or struggling behavior. However, following 72 hr withdrawal, ethanol-exposed mice showed less immobility and greater swimming behavior compared to air-exposed mice. Interestingly, cellular 3α,5α-THP levels were increased in the lateral amygdala 8 hr and 72 hr post-withdrawal in stressed ethanol-exposed mice compared to ethanol-exposed/non-stressed mice. In the paraventricular nucleus of the hypothalamus, stress exposure decreased 3α,5α-THP levels compared to controls following 72 hr withdrawal, but no differences were observed 8 hr post-withdrawal. There were no differences in cellular 3α,5α-THP levels in the nucleus accumbens shell at either withdrawal time point. These data

  20. Intermittent hypoxia can aggravate motor neuronal loss and cognitive dysfunction in ALS mice.

    Directory of Open Access Journals (Sweden)

    Sung-Min Kim

    Full Text Available BACKGROUND: Patients with ALS may be exposed to variable degrees of chronic intermittent hypoxia. However, all previous experimental studies on the effects of hypoxia in ALS have only used a sustained hypoxia model and it is possible that chronic intermittent hypoxia exerts effects via a different molecular mechanism from that of sustained hypoxia. No study has yet shown that hypoxia (either chronic intermittent or sustained can affect the loss of motor neurons or cognitive function in an in vivo model of ALS. OBJECTIVE: To evaluate the effects of chronic intermittent hypoxia on motor and cognitive function in ALS mice. METHODS: Sixteen ALS mice and 16 wild-type mice were divided into 2 groups and subjected to either chronic intermittent hypoxia or normoxia for 2 weeks. The effects of chronic intermittent hypoxia on ALS mice were evaluated using the rotarod, Y-maze, and wire-hanging tests. In addition, numbers of motor neurons in the ventral horn of the spinal cord were counted and western blot analyses were performed for markers of oxidative stress and inflammatory pathway activation. RESULTS: Compared to ALS mice kept in normoxic conditions, ALS mice that experienced chronic intermittent hypoxia had poorer motor learning on the rotarod test, poorer spatial memory on the Y-maze test, shorter wire hanging time, and fewer motor neurons in the ventral spinal cord. Compared to ALS-normoxic and wild-type mice, ALS mice that experienced chronic intermittent hypoxia had higher levels of oxidative stress and inflammation. CONCLUSIONS: Chronic intermittent hypoxia can aggravate motor neuronal death, neuromuscular weakness, and probably cognitive dysfunction in ALS mice. The generation of oxidative stress with activation of inflammatory pathways may be associated with this mechanism. Our study will provide insight into the association of hypoxia with disease progression, and in turn, the rationale for an early non-invasive ventilation treatment in

  1. Intermittent hypoxia and isoniazid plus rifampicin affect hepatic ultrastructure in mice

    Institute of Scientific and Technical Information of China (English)

    WU Run-hua; ZENG Yi-ming; CHEN Xiao-yang

    2011-01-01

    Background Chronic intermittent hypoxia is the most important pathophysiologic feature of sleep apnea syndrome.The present study aimed to determine whether chronic intermittent hypoxia,which is associated with sleep apnea syndrome,can cause or increase damage to liver cell ultrastructure induced by isoniazid and rifampicin in mice.Methods Based on a 2x2 full factorial design consisting of two factors of chronic intermittent hypoxia and isoniazid plus rifampicin,32 male C57B6J mice were randomized into the control group,the chronic intermittent hypoxia group,the isoniazid plus rifampicin group,and the chronic intermittent hypoxia + isoniazid plus rifampicin group.Twelve weeks after treatment,we examined the ultrastructure of liver cells and quantitatively analyzed mitochondrial morphology in C57B6J mice.Results Chronic intermittent hypoxia did not significantly affect the ultrastructure of liver cells.The main effect of chronic intermittent hypoxia did not lead to an increase of mean profile area or mean perimeter of mitochondria,and a decrease of numerical density on area of mitochondria (all P >0.05).Isoniazid plus rifampicin significantly affected liver cell ultrastructure.The main effect of isoniazid plus rifampicin resulted in an increase of mean profile area and mean perimeter of mitochondria,and a decrease of numerical density on area of mitochondria (all P <0.05).Moreover,there was a positive interaction among the chronic intermittent hypoxia and the isoniazid plus rifampicin groups for mean profile area,mean perimeter,and numerical density on area of mitochondria (all P<0.05).Conclusion Chronic intermittent hypoxia and isoniazid plus rifampicin treatment lead to synergistic liver cell ultrastructural injury.

  2. Chronic cannulation for intermittent intravenous fluid administration.

    Science.gov (United States)

    Mostardi, R A; Worsencroft, D; Stern, J; Vanessen, F

    1975-04-01

    A system is described for rapid and effective venous cannulation for long-term administration of fluids in rabbits. This method is completely free of any harness or sling-type apparatus and in no way interferes with the normal mobility of the animal. The animals maintained in this way have participated in programs of tri-weekly administration (2-3 ml/dose) of fluid for as long as 5 mo. PMID:1141108

  3. Intermittent hypoxia and neurorehabilitation.

    Science.gov (United States)

    Gonzalez-Rothi, Elisa J; Lee, Kun-Ze; Dale, Erica A; Reier, Paul J; Mitchell, Gordon S; Fuller, David D

    2015-12-15

    In recent years, it has become clear that brief, repeated presentations of hypoxia [i.e., acute intermittent hypoxia (AIH)] can boost the efficacy of more traditional therapeutic strategies in certain cases of neurologic dysfunction. This hypothesis derives from a series of studies in animal models and human subjects performed over the past 35 yr. In 1980, Millhorn et al. (Millhorn DE, Eldridge FL, Waldrop TG. Respir Physiol 41: 87-103, 1980) showed that electrical stimulation of carotid chemoafferent neurons produced a persistent, serotonin-dependent increase in phrenic motor output that outlasts the stimulus for more than 90 min (i.e., a "respiratory memory"). AIH elicits similar phrenic "long-term facilitation" (LTF) by a mechanism that requires cervical spinal serotonin receptor activation and de novo protein synthesis. From 2003 to present, a series of studies demonstrated that AIH can induce neuroplasticity in the injured spinal cord, causing functional recovery of breathing capacity after cervical spinal injury. Subsequently, it was demonstrated that repeated AIH (rAIH) can induce recovery of limb function, and the functional benefits of rAIH are greatest when paired with task-specific training. Since uncontrolled and/or prolonged intermittent hypoxia can elicit pathophysiology, a challenge of intermittent hypoxia research is to ensure that therapeutic protocols are well below the threshold for pathogenesis. This is possible since many low dose rAIH protocols have induced functional benefits without evidence of pathology. We propose that carefully controlled rAIH is a safe and noninvasive modality that can be paired with other neurorehabilitative strategies including traditional activity-based physical therapy or cell-based therapies such as intraspinal transplantation of neural progenitors. PMID:25997947

  4. Fate in intermittent claudication

    DEFF Research Database (Denmark)

    Jelnes, Rolf; Gaardsting, O; Hougaard Jensen, K;

    1986-01-01

    113 of the patients (44%) had died. Causes of death were no different from those in the general population. Mortality was twice that of the general population matched for age and sex. Mortality among the men was twice that among the women. In men under 60 mortality was four times that expected......, or an ankle/arm pressure index below 50% were individually significantly associated with progression of the arteriosclerotic disease. These findings show the importance of peripheral blood pressure measurements in the management of patients with intermittent claudication due to arteriosclerotic disease....

  5. Interventions for intermittent exotropia

    Science.gov (United States)

    Hatt, Sarah R; Gnanaraj, Lawrence

    2014-01-01

    Background The clinical management of intermittent exotropia has been discussed extensively in the literature, yet there remains a lack of clarity regarding indications for intervention, the most effective form of treatment and whether or not there is an optimal time in the evolution of the disease at which any treatment should be carried out. Objectives The objective of this review was to analyse the effects of various surgical and non-surgical treatments in randomised trials of participants with intermittent exotropia, and to report intervention criteria and determine the significance of factors such as age with respect to outcome. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library, Issue 4, 2012), MEDLINE (January 1966 to May 2012), EMBASE (January 1980 to May 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to May 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 4 May 2012. We are no longer searching the UK Clinical Trials Gateway (UKCTG) for this review. We manually searched the British Orthoptic Journal up to 2002, and the proceedings of the European Strabismological Association (ESA), International Strabismological Association (ISA) and American Academy of Paediatric Ophthalmology and Strabismus meeting (AAPOS) up to 2001. We contacted researchers who are active in the field for information about further published or unpublished studies. Selection criteria We included randomised controlled trials of any surgical or non-surgical treatment for intermittent exotropia. Data collection and

  6. Quality of life and functional status after revascularization or conservative treatment in patients with intermittent claudication

    DEFF Research Database (Denmark)

    Hedeager Momsen, Anne-Mette; Bach Jensen, Martin; Norager, Charlotte Buchard;

    2011-01-01

    Revascularization of patients with intermittent claudication (IC) is recommended only for selected patients who have chronic pain or disabling disease. However, improvement in the quality of life (QoL) could justify more widespread use.......Revascularization of patients with intermittent claudication (IC) is recommended only for selected patients who have chronic pain or disabling disease. However, improvement in the quality of life (QoL) could justify more widespread use....

  7. Comment on "Intermittent plate tectonics?".

    Science.gov (United States)

    Korenaga, Jun

    2008-06-01

    Silver and Behn (Reports, 4 January 2008, p. 85) proposed that intermittent plate tectonics may resolve a long-standing paradox in Earth's thermal evolution. However, their analysis misses one important term, which subsequently brings their main conclusion into question. In addition, the Phanerozoic eustasy record indicates that the claimed effect of intermittency is probably weak.

  8. The express of PTP-1 B and IRS-1 in liver cells of rats during chronic intermittent hypoxic%PTP-1B 及 IRS-1在慢性间歇低氧大鼠肝细胞中的表达

    Institute of Scientific and Technical Information of China (English)

    赵勇; 任寿安; 蔡月伟

    2015-01-01

    目的:探讨慢性间歇低氧(CIH)对大鼠肝细胞蛋白酪氨酸磷酸酶-1B(protein tyrosine phosphatase-1B,PTP-1B)及胰岛素受体底物-1(insulin receptor substrate-1,IRS-1)蛋白表达量的影响及其导致胰岛素抵抗发生的可能机制。方法选取健康雄性 SD 大鼠24只,按随机数字表法分为正常对照组(NC 组)、慢性间歇低氧4周组(CIH4组)、慢性间歇低氧8周组(CIH8组),每组8只。NC 组无间歇低氧暴露正常饲养,CIH4组及 CIH8组于上午9时至下午5时放入间歇低氧仓暴露于间歇低氧环境中,舱内最低氧浓度为6%~7%。分别于第4周及第8周检测大鼠空腹血糖及空腹胰岛素水平,用稳态模型胰岛素抵抗指数(HOMA-IR)以及胰岛素敏感指数(insulin sensitive index,ISI)评价胰岛素抵抗, SABC 法免疫组织化学试剂盒检测 CIH 大鼠肝细胞 PTP-1B 及 IRS-1蛋白表达,以平均灰度值表示PTP-1B 及 IRS-1的蛋白表达量,并做统计学分析。结果与 NC 组比较,CIH4组及 CIH8组空腹血糖、空腹胰岛素及 HOMA-IR 升高,ISI 降低,差异有统计学意义(P <0.05),且 CIH8组更为显著;与 NC 组相比较,CIH4组及 CIH8组 PTP-1B 蛋白表达增加,IRS-1蛋白表达减少,差异有统计学意义(P <0.05),Pearson 相关分析显示,HOMA-IR 与 PTP-1B 平均灰度值呈负相关、与 IRS-1平均灰度值呈正相关;ISI 与 PTP-1B 平均灰度值呈正相关、与 IRS-1平均灰度值呈负相关。结论①CIH 暴露使大鼠空腹血糖及胰岛素水平升高且发生胰岛素抵抗,随着 CIH 暴露时间的延长,胰岛素抵抗程度加重。②CIH 导致大鼠肝细胞 PTP-1B 蛋白表达增加,IRS-1蛋白表达减少,PTP-1B 及 IRS-1可能共同参与了 CIH 大鼠胰岛素抵抗的发生发展。%Objective To investigate the effects of chronic intermittent hypoxia on the expression of PTP-1B and IRS-1 and the possible mechanism of insulin resistance caused by chronic intermittent hypoxia.Methods According to the

  9. Construction of An Experimental Hypogiossal Nerve Signals Record Platform in Rat Model of Chronic Intermittent Hypoxia in Vivo%慢性间歇低氧大鼠模型在体舌下神经电信号记录实验平台的建立

    Institute of Scientific and Technical Information of China (English)

    赵景景; 文芳静; 王念; 范慧; 万志辉; 胡克

    2012-01-01

    Objective: To establish an experimental platform of the rat model of chronic intermittent hy-poxia simulating obstructive sleep apnea syndrome and to explore the activity of the hypoglossal nerve signals in vivo. Methods: Experiments were performed in the rat model of chronic intermittent hypoxia. These preparations included the gas source, the gas control delivery system, the intermittent hypoxia animal chambers, and the rats. In accordance with the requirement of experiment, the rats were given nitrogen and air alternately for 8 hours per day and the experiment lasted for 7 weeks. After the experiment, the hypoglossal nerve was isolated and the average peak amplitude and frequency of hypoglossal nerve discharges were recorded and analyzed with medical biological signal processor (MedLab U/C 501H). Results: The pre-test results showed that chronic intermittent hypoxia rat model could simulate the pathophysiological characteristics of the obstructive sleep apnea hypopnea syndrome in human, and the recorded signals from hypoglossal nerve are stable and reliable. Conclusion; The chronic intermittent hypoxia model proved simple, easy, practical, and reproducible, and the recorded signals of hypoglossal nerve are stable and reliable. The system is ideally suited for studies.%目的:建立一种以模拟阻塞性睡眠呼吸暂停低通气综合征的慢性间歇低氧大鼠模型为基础、探讨在体舌下神经电信号活动的实验平台.方法:慢性间歇低氧大鼠模型由气源(氮气及空气)、电磁阀控制系统、间歇低氧动物仓、以及实验动物(大鼠)组成,按照实验要求对大鼠交替给予氮气和空气,每天8h,连续处理7周后,分离舌下神经,应用多通道生物信号采集与处理系统对舌下神经电信号进行处理与分析.结果:预实验结果显示,慢性间歇低氧大鼠模型能够模拟人体阻塞性睡眠呼吸暂停低通气综合征的病理生理特征,所记录的电信号稳定、可靠.结论:

  10. 慢性间歇低氧对大鼠肝细胞SOCS3表达的影响%The effect of SOCS3 expression on rat liver cells by chronic intermittent hypoxic

    Institute of Scientific and Technical Information of China (English)

    任寿安; 康耀文; 蔡月伟

    2014-01-01

    Objective To established chronic intermittent hypoxic (CIH) animal model for investigate the mechanism of insulin resistance caused by CIH.Methods Twenty-four healthy male SD rats were randomly divided into four groups:normal control group (NC group),CIH 2 weeks group (CIH2 group),and CIH 5 weeks group (CIH5 group),with 8 rats in each group.The minimum oxygen concentration was 6%-7% in animal chamber.About 8 hours per day (from 9AM to 5 PM),the experimental lasted for 35 days.The rats in control group were placed in the same animal box without CIH.After the experiment,to measure fasting blood glucose and insulin levels by radioimmunoassay and then according to the homeostasis model of insulin resistance index (HOMA) was calculated.The expressions of SOCS3 protein were detected with immunohistochemical method in rat liver cells.To detect the SOCS3-mRNA gene expression by reverse transcription and polymerase chain reaction (RT-PCR).Results Compared with the NC group,fasting blood glucose(F =33.582,P <0.05),insulin level (F =35.633,P <0.05) and HOMA-IR (F =49.045,P <0.05) of the CIH2.CIH5 group was higher than other groups (P <0.05).Compared with the NC group,the expression of SOCS3 protein was increased in CIH2 and CHI5 group (F =9.472,P <0.05),but in CIH2 and CIH5 group were no significantly differences (P >0.05).And then the expression of SOCS3-mRNA in CIH5 was higher than CIH2 and CIH5 group (F =8.665,P < 0.05).Pearson correlation analysis showed that HOMA-IR and the expression of SOCS3 protein was negatively correlated (r =-0.759,P <0.001) and was positively correlated with SOCS3-mRNA (r =0.603,P =0.01).Conclusions ①CIH exposure caused fasting blood glucose level and increase insulin level and insulin resistance in rats with CIH.With the intermittent hypoxic exposure time prolonged,the degree of insulin resistance was increased.②CIH leads to increased expression of SOCS3 protein and SOCS3-mRNA gene in rat liver cells with CIH exposure

  11. High-Intensity Intermittent Exercise: Effect on Young People's Cardiometabolic Health and Cognition.

    Science.gov (United States)

    Cooper, Simon B; Dring, Karah J; Nevill, Mary E

    2016-01-01

    With only a quarter of young people currently meeting physical activity guidelines, two key areas of concern are the effects of exercise on cardiometabolic health and cognition. Despite the fact that physical activity in young people is typically high intensity and intermittent in nature, much of the literature examines traditional endurance-type exercise. This review provides an update on the effects of high-intensity intermittent exercise on young people's cardiometabolic health and cognition. High-intensity intermittent exercise has acute beneficial effects on endothelial function and postprandial lipemia and chronic positive effects on weight management. In addition, there is emerging evidence regarding chronic benefits on the blood lipid profile, blood pressure, and proinflammatory and anti-inflammatory cytokines. Furthermore, emerging evidence suggests beneficial acute and chronic effects of high-intensity intermittent exercise on cognition. However, further research is required in both cardiometabolic health and cognition, particularly regarding the impact of school-based interventions in adolescents. PMID:27399821

  12. Intermedia and Intermittency

    Directory of Open Access Journals (Sweden)

    Veres Bálint

    2014-12-01

    Full Text Available It is commonly known that medial reflections have been initiated by attempts to secure the borders of discrete medial forms and to define the modus operandi of each essentialized medial area. Later on, the focus of study has shifted to plurimedial formations and the interactions between predefined medial genres. In the last few decades, taxonomic approaches to various multi-, inter-, and transmedial phenomena dominated the discussions, which offered invaluable support in mapping the terrain, but at the same time hindered the analysis of the ephemeral, time-dependent aspects of plurimedial operations. While we explore the properties of each medial configuration, we lose sight of the actual historical drivers that produce ever-new configurations. My thesis is that any discourse on intermediality should be paralleled by a discourse on cultural intermittency, and consequently, media studies should involve an approach that focuses on the “ecosystem” of the constantly renewing media configurations from the point of view of their vitalizing potential and capability to trigger heightened experiences. This approach draws much inspiration from K. Ludwig Pfeiffer’s media anthropology that gives orientation in my paper.

  13. Intermittency Growth in Fluid Turbulence

    Institute of Scientific and Technical Information of China (English)

    ZHU Jian-Zhou

    2006-01-01

    @@ Measurement and phenomenological analyses of intermittency growth in an experimental turbulent pipe flow and numerical turbulence are performed, for which working definitions such as degree, increment, and growth rate of intermittency are introduced with the help of quasiscaling theory. The logarithmic-normal inertial scaling model is extended to quasiscaling as the second-order truncation of the Taylor expansion and is used for studying the intermittency growth problem. The extended self-similarity properties are shown to be not consistent with the monotonicity of the third order local quasiscaling exponent and the nonmonotonic behaviour of the intermittency growth rate as a result of bottleneck. Digestions of the results with scale-dependent multifractals are provided.

  14. Mechanism of endocannabinoids system in glucose metabolism of rats with chronic intermittent hypoxia%内源性大麻素系统对慢性间歇低氧大鼠糖代谢的影响机制

    Institute of Scientific and Technical Information of China (English)

    肖玲; 陈彦; 张晋源; 王蓓

    2014-01-01

    目的 探讨内源性大麻素系统(ECS)对慢性间歇低氧(CIH)大鼠糖代谢的影响机制.方法 将48只Wistar大鼠采用随机排列表法及实验结束时间分为4、6周正常对照组(充入压缩空气氧浓度为21%),4、6周CIH组(每日CIH暴露8h)及4、6周CIH+利莫那班组[CIH暴露前给予肝脏CB1受体拮抗剂利莫那班腹腔注射(1 mg·kg-1·d-1)]各8只.第4周及第6周结束实验,检测各组大鼠空腹血糖、血清胰岛素、血清C肽水平及肝脏CB1受体表达的变化,评价CIH对糖代谢指标的影响.结果 4、6周CIH组下列指标均显著高于4、6周正常对照组:空腹血糖(8.91±0.40)、(10.61 ±0.36)比(6.48±0.23)、(6.51 ±0.25) mmol/L,血清胰岛素(16.72 ±3.76)、(20.25 ±3.64)比(9.02±2.05)、(9.19 ±2.35) U/L,血清C肽水平(3.53±0.26)、(5.23±0.29)比(1.37±0.26)、(1.41 ±0.41) μg/L,肝脏CB1受体表达(0.290±0.026)、(0.342±0.030)比(0.214±0.023)、(0.221 ±0.026)(均P<0.05);且6周CIH组均显著高于4周CIH组(均P<0.05);而4、6周CIH+利莫那班组上述指标明显降低(均P<0.05).CB1水平与空腹血糖、血清胰岛素、血清C肽水平呈正相关(r=0.856、0.758、0.827,均P<0.05).结论 ECS在CIH引发的糖代谢异常中发挥一定的促进作用.%Objective To explore the mechanism of endocannabinoids system (ECS) in glucose metabolism of rats with chronic intermittent hypoxia (CIH).Methods According to random permutation table and experiment time,a total of 48 Wistar rats were randomly divided into 6 groups of 4/6-week control (filling with compressed air with 21% oxygen),4/6-week CIH (CIH exposure for 8 hours per day) and 4/ 6-week CIH plus rimonabant group [an intraperitoneal injection of CB1 receptor antagonist rimonabant into liver (1 mg · kg-1 · d-1) before CIH exposure] (n =8 each).The levels of fasting plasma glucose,serum insulin,serum C-peptide and the expression of CB1 receptor in liver were detected after 4/6 weeks to evaluate the

  15. Chronic penile strangulation

    OpenAIRE

    Lopes, Roberto I.; Silvia I Lopes; Roberto N. Lopes

    2003-01-01

    Chronic penile strangulation is exceedingly rare with only 5 cases previously reported. We report an additional case of progressive penile lymphedema due to chronic intermittent strangulation caused by a rubber band applied to the penile base for 6 years. A 49-year-old man presented incapacity to exteriorize the glans penis. For erotic purposes, he had been using a rubber-enlarging band placed in the penile base for 6 years. With chronic use, he noticed that his penis swelled. Physical examin...

  16. Chronic stress in adulthood followed by intermittent stress impairs spatial memory and the survival of newborn hippocampal cells in aging animals: prevention by FGL, a peptide mimetic of neural cell adhesion molecule

    DEFF Research Database (Denmark)

    Borcel, Erika; Pérez-Alvarez, Laura; Herrero, Ana Isabel;

    2008-01-01

    In this study, we examined whether chronic stress in adulthood can exert long-term effects on spatial-cognitive abilities and on the survival of newborn hippocampal cells in aging animals. Male Wistar rats were subjected to chronic unpredictable stress at midlife (12 months old) and then reexposed...... each week to a stress stimulus. When evaluated in the water maze at the early stages of aging (18 months old), chronic unpredictable stress accelerated spatial-cognitive decline, an effect that was accompanied by a reduction in the survival of newborn cells and in the number of adult granular cells......, a peptide mimetic of neural cell adhesion molecule, during the 4 weeks of continuous stress not only prevented the deleterious effects of chronic stress on spatial memory, but also reduced the survival of the newly generated hippocampal cells in aging animals. FGL treatment did not, however, prevent...

  17. [Intermittent hemodialysis, irreplaceable in specific cases of severe poisoning].

    Science.gov (United States)

    Ventresca, M; Teta, D; Burnier, M; Kissling, S

    2015-02-25

    The medical practitioner is in general well aware of the indications for hemodialysis in severe, acute or chronic renal insufficiency. Apart from the traditional indications for renal replacement therapy, there are some cases such as metfomin and ethylene glycol poisoning, lithium intoxication severe hypercalcemia and tumor lysis syndrome, in which intermittent hemodialysis is the most effective treatment, or sometimes the only effective one. Although these situations remain infrequent, it is crucial to recognize them as quickly as possible. PMID:25898458

  18. Bursts in intermittent aeolian saltation

    CERN Document Server

    Carneiro, M V; Herrmann, H J

    2014-01-01

    Close to the onset of Aeolian particle transport through saltation we find in wind tunnel experiments a regime of intermittent flux characterized by bursts of activity. Scaling laws are observed in the time delay between each burst and in the measurements of the wind fluctuations at the critical Shields number $\\theta_c$. The time delay between each burst decreases on average with the increase of the Shields number until saltation becomes non-intermittent and the sand flux becomes continuous. A numerical model for saltation including the wind-entrainment from the turbulent fluctuations can reproduce these observations and gives insight about their origin. We present here also for the first time measurements showing that with feeding it becomes possible to sustain intermittent flux even below the threshold $\\theta_c$ for natural saltation initiation.

  19. Elastic wave turbulence and intermittency

    Science.gov (United States)

    Chibbaro, Sergio; Josserand, Christophe

    2016-07-01

    We investigate the onset of intermittency for vibrating elastic plate turbulence in the framework of the weak wave turbulence theory using a numerical approach. The spectrum of the displacement field and the structure functions of the fluctuations are computed for different forcing amplitudes. At low forcing, the spectrum predicted by the theory is observed, while the fluctuations are consistent with Gaussian statistics. When the forcing is increased, the spectrum varies at large scales, corresponding to the oscillations of nonlinear structures made of ridges delimited by d cones. In this regime, the fluctuations exhibit small-scale intermittency that can be fitted via a multifractal model. The analysis of the nonlinear frequency shows that the intermittency is linked to the breakdown of the weak turbulence at large scales only.

  20. Intermittency in spherical Couette dynamos

    CERN Document Server

    Raynaud, Raphaël; 10.1103/PhysRevE.87.033011

    2013-01-01

    We investigate dynamo action in three-dimensional numerical simulations of turbulent spherical Couette flows. Close to the onset of dynamo action, the magnetic field exhibits an intermittent behavior, characterized by a series of short bursts of the magnetic energy separated by low-energy phases. We show that this behavior corresponds to the so-called on-off intermittency. This behavior is here reported for dynamo action with realistic boundary conditions. We investigate the role of magnetic boundary conditions in this phenomenon.

  1. 胸部物理治疗联合间歇无创机械通气在慢性阻塞性肺疾病呼吸衰竭患者中的应用%Combination of chest physiotherapy and intermittent non-invasive mechanical ventilation for chronic obstructive pulmonary disease patients with respiratory failure

    Institute of Scientific and Technical Information of China (English)

    瞿云中; 彭红; 陈平; 向旭东

    2009-01-01

    目的:探讨胸部物理治疗(chest physiotherapy,CPT)联合间歇无创机械通气在慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)合并呼吸衰竭患者中应用的效果.方法:将2006年1月至2007年12月在中南大学湘雅二医院呼吸科行无创机械通气的COPD合并呼吸衰竭患者90例按随机数字表法分为两组.对照组45例(男性35例,女性10例),35~83(61.2±3.0)岁,常规治疗后给予间歇双水平正压无创通气(bi-level positive airway pressure,BiPAP)每次2 h,每6 h 1次或者每次2 h,每8 h 1次的治疗;胸部物理治疗(CPT)组45例(男性36例,女性9例),38~82(61.5±5.0)岁,在Bi-PAP治疗基础上予CPT.两组分别观察主要症状、肺部体征、胸部X线片、无创通气应用时间和治疗后PaO2和PaCO2等指标.结果:与对照组相比,CPT组患者血气改善明显,达到症状缓解、肺部体征改善、胸部x线片吸收所需天数、无创通气应用时间均明显缩短(P<0.05).结论:在需使用无创正压间歇机械通气的COPD合并呼吸衰竭患者中给予CPT,能有效地提高治疗效果,两者联合在COPD合并呼吸衰竭患者的治疗中有协同作用.%Objective To determine the effect of combination of chest physiotherapy (CPT) and intermittent non-invasive ventilation for chronic obstructive pulmonary disease (COPD) patients with respiratory failure. Methods Ninety COPD patients with intermittent bi-level positive airway pressure (BiPAP) ventilation were randomly divided into 2 groups : control group (n=45) received BiPAP treatment after conventional anti-infection, phlegm treatment and support treatment; CPT group (n=45) received CPT before BiPAP treatment. Clinical symptoms, chest signs, chest X-ray, time of BiPAP therapy, PaO2, and PaCO2 after the treatment were evaluated. Results Compared with with the control group, patients in the CPT group significantly improved in clinical symptoms, chest signs, chest X-ray absorption as well as shorter

  2. Intermittent control of coexisting attractors.

    Science.gov (United States)

    Liu, Yang; Wiercigroch, Marian; Ing, James; Pavlovskaia, Ekaterina

    2013-06-28

    This paper proposes a new control method applicable for a class of non-autonomous dynamical systems that naturally exhibit coexisting attractors. The central idea is based on knowledge of a system's basins of attraction, with control actions being applied intermittently in the time domain when the actual trajectory satisfies a proximity constraint with regards to the desired trajectory. This intermittent control uses an impulsive force to perturb one of the system attractors in order to switch the system response onto another attractor. This is carried out by bringing the perturbed state into the desired basin of attraction. The method has been applied to control both smooth and non-smooth systems, with the Duffing and impact oscillators used as examples. The strength of the intermittent control force is also considered, and a constrained intermittent control law is introduced to investigate the effect of limited control force on the efficiency of the controller. It is shown that increasing the duration of the control action and/or the number of control actuations allows one to successfully switch between the stable attractors using a lower control force. Numerical and experimental results are presented to demonstrate the effectiveness of the proposed method. PMID:23690639

  3. Effects of gestational age and surface modification on materno-fetal transfer of nanoparticles in murine pregnancy

    Science.gov (United States)

    Yang, Hui; Sun, Cuiji; Fan, Zhenlin; Tian, Xin; Yan, Liang; Du, Libo; Liu, Yang; Chen, Chunying; Liang, Xing-Jie; Anderson, Gregory J.; Keelan, Jeffrey A.; Zhao, Yuliang; Nie, Guangjun

    2012-11-01

    Nanoparticle exposure in pregnancy may result in placental damage and fetotoxicity; however, the factors that determine fetal nanoparticle exposure are unclear. Here we have assessed the effect of gestational age and nanoparticle composition on fetal accumulation of maternally-administered nanomaterials in mice. We determined the placental and fetal uptake of 13 nm gold nanoparticles with different surface modifications (ferritin, PEG and citrate) following intravenous administration at E5.5-15.5. We showed that prior to E11.5, all tested nanoparticles could be visualized and detected in fetal tissues in significant amounts; however, fetal gold levels declined dramatically post-E11.5. In contrast, Au-nanoparticle accumulation in the extraembryonic tissues (EET) increased 6-15 fold with gestational age. Fetal and EET accumulation of ferritin- and PEG-modified nanoparticles was considerably greater than citrate-capped nanoparticles. No signs of toxicity were observed. Fetal exposure to nanoparticles in murine pregnancy is, therefore, influenced by both stage of embryonic/placental maturation and nanoparticle surface composition.

  4. Relación materno fetal y establecimiento del apego durante la etapa de gestación

    OpenAIRE

    Gómez Masera, Raquel; Alonso Martín, Pilar; Rivera Pavón, Irene

    2011-01-01

    A diario vemos ejemplos de noticias por las que nos preguntamos qué pasa por la mente de una madre para llegar a tratar de una forma tan negativa a sus hijos. Es conocida la gran importancia que tiene para el desarrollo cognitivo, emocional y social durante la infancia, el establecimiento de una adecuada relación de apego madre-bebé, desde el inicio de su vida. Pero poco se ha estudiado sobre la importancia de la formación de este apego a lo largo del embarazo. Este trabajo trata ...

  5. Low and high dietary protein:carbohydrate ratios during pregnancy affect materno-fetal glucose metabolism in pigs.

    Science.gov (United States)

    Metges, Cornelia C; Görs, Solvig; Lang, Iris S; Hammon, Harald M; Brüssow, Klaus-Peter; Weitzel, Joachim M; Nürnberg, Gerd; Rehfeldt, Charlotte; Otten, Winfried

    2014-02-01

    Inadequate dietary protein during pregnancy causes intrauterine growth retardation. Whether this is related to altered maternal and fetal glucose metabolism was examined in pregnant sows comparing a high-protein:low-carbohydrate diet (HP-LC; 30% protein, 39% carbohydrates) with a moderately low-protein:high-carbohydrate diet (LP-HC; 6.5% protein, 68% carbohydrates) and the isoenergetic standard diet (ST; 12.1% protein, 60% carbohydrates). During late pregnancy, maternal and umbilical glucose metabolism and fetal hepatic mRNA expression of gluconeogenic enzymes were examined. During an i.v. glucose tolerance test (IVGTT), the LP-HC-fed sows had lower insulin concentrations and area under the curve (AUC), and higher glucose:insulin ratios than the ST- and the HP-LC-fed sows (P < 0.05). Insulin sensitivity and glucose clearance were higher in the LP-HC sows compared with ST sows (P < 0.05). Glucagon concentrations during postabsorptive conditions and IVGTT, and glucose AUC during IVGTT, were higher in the HP-LC group compared with the other groups (P < 0.001). (13)C glucose oxidation was lower in the HP-LC sows than in the ST and LP-HC sows (P < 0.05). The HP-LC fetuses were lighter and had a higher brain:liver ratio than the ST group (P < 0.05). The umbilical arterial inositol concentration was greater in the HP-LC group (P < 0.05) and overall small fetuses (230-572 g) had higher values than medium and heavy fetuses (≥573 g) (P < 0.05). Placental lactate release was lower in the LP-HC group than in the ST group (P < 0.05). Fetal glucose extraction tended to be lower in the LP-HC group than in the ST group (P = 0.07). In the HP-LC and LP-HC fetuses, hepatic mRNA expression of cytosolic phosphoenolpyruvate carboxykinase (PCK1) and glucose-6-phosphatase (G6PC) was higher than in the ST fetuses (P < 0.05). In conclusion, the HP-LC and LP-HC sows adapted by reducing glucose turnover and oxidation and having higher glucose utilization, respectively. The HP-LC and LP-HC fetuses adapted via prematurely expressed hepatic gluconeogenic enzymes.

  6. [Contribution of direct bacteriologic examinations to the diagnosis of early materno-fetal bacterial infection: the Lille experience].

    Science.gov (United States)

    Trivier, D; Dubos, J P; Mteyrek, M; Codaccioni, X; Courcol, R J; Husson, M O

    1999-10-01

    A prospective study was conducted in 3056 live-born infants delivered at the Jeanneade-Flandre maternity hospital of the Lille Teaching Hospital between January and August 1997. Clinical, laboratory test, and microbiological test findings were compared. A cohort of 1003 infants who remained in the maternity ward but were considered at increased risk of maternofetal infection (MFI) based on history and/or obstetrical criteria and/or neonatal criteria underwent routine collection of specimens including gastric fluid, auricular and anal swabs, amniotic fluid, and placental fragments. Microscopic examination of gastric fluid smears, the first result available to the clinician, was found to have 27.5% sensitivity (983 samples). Positive predictive value (PPV) was only 17.8% because of a high rate of colonization (16.8%), defined as absence of clinical symptoms and three peripheral specimens positive for the same organism. However, negative predictive value (NPV) was as high as 99.8% as a result of high sensitivity (97.8%) in the infected neonates. The gastric fluid smear was positive in 30% and 35% of neonates born to mothers with hyperpyrexia during early and late labor, respectively, and in 42% of neonates born to mothers with a history of group B streptococcus carriage during the pregnancy. Forty-two per cent of neonates with a history of fetal tachycardia had a positive gastric fluid smear. Diagnostic criteria for infection were three peripheral specimens positive for the same organism, C-reactive protein elevation, and/or one or more clinical signs suggestive of infection, and/or a positive central specimen (blood, CSF). The infection rate in infants who remained in the maternity ward was 1.6%. The most common causative organisms were group B streptococci. These findings illustrate the useful contribution of gastric fluid smears to the early diagnosis of MFI and confirm the predominant role of group B streptococci. PMID:10573697

  7. 2种慢性间歇性缺氧小鼠模型模拟气阴两虚证临床指征的比较研究%Comparison of Clinical Indications Simulating Deficiency of Both Qi and Yin Syndrome Induced by Two Types of Chronic Intermittent Hypoxia in Mice

    Institute of Scientific and Technical Information of China (English)

    王文萍; 柴程芝; 寇俊萍; 余伯阳

    2011-01-01

    目的:比较钠石灰和低压氧仪2种不同缺氧方式诱导的慢性间歇性缺氧小鼠模型的整体行为变化,为进一步构建气阴两虚证动物模型奠定基础.方法:分别采用氧分压从21%逐渐降至6%,平均下降速度为0.5%/min ~ 1%/min的钠石灰缺氧法和氧分压在短时间内骤降后维持在7% ~8%的低压氧仪缺氧法,考察2种缺氧模式对小鼠体重,摄食量,自发活动以及心率、T波等气阴两虚临床相关指标变化的影响.结果:钠石灰和低压氧仪2种不同的缺氧方式均能够导致小鼠体重下降;摄食量减少;行走格数减少,直立次数增加等自发活动改变;心率加快,T波持续抬高等心电图变化,二者对各项指标的影响呈基本一致的趋势,其结果具有显著相关性.结论:钠石灰和低压氧仪2种缺氧方式诱导的慢性间歇性缺氧小鼠模型均能够模拟形体消瘦,食欲不振,体倦乏力,烦躁,心悸,脉细数等气阴两虚证的主要临床特征.%Objective: To establish foundation for constructing a suitable animal model of deficiency of both Qi and Yin syndrome (DQYS) induced by two types of chronic intermittent hypoxia (soda lime and low-pressureoxygen controller) by comparison the whole behavior in mice. Method: The two modes of oxygen scarcity,including oxygen pressure declining continuously from 21% to 7%-8% with the average speed of 0. 5%/min-l% per minute in airtight wide-mouthed bottle and oxygen pressure falling abruptly within short period and then keeping in the level of 7% -8% ,were adopted respectively to observe the time-course changes in body weight, food intake, locomotive activity and electrocardiogram respectively. The experiments were designed for mimicing clinical features of DQYS. Result; The mice exposed to two different modes of chronic intermittent hypoxia for certain duration showed body weight loss, food intake decline, locomotive activity change of ambulation decrease and rearing increase

  8. Optical diagnostics of intermittent flows

    DEFF Research Database (Denmark)

    Okulov, V.L.; Naumov, I.V.; Sørensen, Jens Nørkær

    2007-01-01

    image velocimetry, frequently give erroneous results, especially for the transition flow and developed nonstationary flow. However, their combined use in diagnostics of unsteady (intermittent) flows significantly improves both the temporal and spatial resolution of measurements. Such a complex approach......The efficiency of combined use of different optical techniques for flow diagnostics is demonstrated with the practically important case of intense swirling flows. It is shown that, when applied separately, commonly used optical measuring techniques, such as laser Doppler anemometry and particle...

  9. Phosphodiesterase-5 inhibition mimics intermittent reoxygenation and improves cardioprotection in the hypoxic myocardium.

    Directory of Open Access Journals (Sweden)

    Giuseppina Milano

    Full Text Available UNLABELLED: Although chronic hypoxia is a claimed myocardial risk factor reducing tolerance to ischemia/reperfusion (I/R, intermittent reoxygenation has beneficial effects and enhances heart tolerance to I/R. AIM OF THE STUDY: To test the hypothesis that, by mimicking intermittent reoxygenation, selective inhibition of phosphodiesterase-5 activity improves ischemia tolerance during hypoxia. Adult male Sprague-Dawley rats were exposed to hypoxia for 15 days (10% O₂ and treated with placebo, sildenafil (1.4 mg/kg/day, i. p., intermittent reoxygenation (1 h/day exposure to room air or both. Controls were normoxic hearts. To assess tolerance to I/R all hearts were subjected to 30-min regional ischemia by left anterior descending coronary artery ligation followed by 3 h-reperfusion. Whereas hypoxia depressed tolerance to I/R, both sildenafil and intermittent reoxygenation reduced the infarct size without exhibiting cumulative effects. The changes in myocardial cGMP, apoptosis (DNA fragmentation, caspase-3 activity (alternative marker for cardiomyocyte apoptosis, eNOS phosphorylation and Akt activity paralleled the changes in cardioprotection. However, the level of plasma nitrates and nitrites was higher in the sildenafil+intermittent reoxygenation than sildenafil and intermittent reoxygenation groups, whereas total eNOS and Akt proteins were unchanged throughout. CONCLUSIONS: Sildenafil administration has the potential to mimic the cardioprotective effects led by intermittent reoxygenation, thereby opening the possibility to treat patients unable to be reoxygenated through a pharmacological modulation of NO-dependent mechanisms.

  10. Glucocorticoid-Induced Osteoporosis in Growing Mice Is Not Prevented by Simultaneous Intermittent PTH Treatment

    NARCIS (Netherlands)

    Postnov, A.; Schutter, de T.; Sijbers, J.; Karperien, H.B.J.; Clerck, de N.

    2009-01-01

    Glucocorticoids (GCs) are widely used in medicine for treatment of chronic diseases. Especially in children, prolonged treatment causes growth retardation and early onset of osteoporosis. Human parathyroid hormone (PTH) has an anabolic effect on bone when administrated intermittently. The aim of the

  11. Effect of Intermittent Hypoxia and Rimonabant on Glucose Metabolism in Rats: Involvement of Expression of GLUT4 in Skeletal Muscle

    OpenAIRE

    Wang, Xiaoya; Yu, Qin; Yue, Hongmei; Zeng, Shuang; Cui, Fenfen

    2015-01-01

    Background Obstructive sleep apnea (OSA) and its main feature, chronic intermittent hypoxia (IH) during sleep, is closely associated with insulin resistance (IR) and diabetes. Rimonabant can regulate glucose metabolism and improve IR. The present study aimed to assess the effect of IH and rimonabant on glucose metabolism and insulin sensitivity, and to explore the possible mechanisms. Material/Methods Thirty-two rats were randomly assigned into 4 groups: Control group, subjected to intermitte...

  12. Improved Intermittency Analysis of Individual Events

    OpenAIRE

    Janik, R. A.; Ziaja, B.

    1998-01-01

    Recent progress on the event-by-event analysis of intermittent data by R. A. Janik and myself is reported. The intermittency analysis of single event data (particle moments) in multiparticle production is improved, taking into account corrections due to the reconstruction of history of a particle cascade. This approach is tested within the framework of the $\\alpha$-model.}

  13. Radiation characteristics of intermittence exhaust noise

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shengdun; SHANG Chunyang; ZHAO Zhigang; SHI Weixiang

    2000-01-01

    Aerodynamic characteristics, the noise characteristics in the course of intermittence exhaust are investigated and the expressions for sound pressure level of the noise generated by single-pole source and quadrupole source in the intermittence exhaust noise are established. The effects of all parameters in pneumatic system on the noise are also comprehensively studied.

  14. COHO SALMON DEPENDENCE ON INTERMITTENT STREAMS

    Science.gov (United States)

    In February 2006, the US Supreme Court heard cases that may affect whether intermittent streams are jurisdictional waters under the Clean Water Act. In June 2006, however, the cases were remanded to the circuit court, leaving the status of intermittent streams uncertain once agai...

  15. Viral and host factors related with histopathologyc activity in patients with chronic hepatitis B and moderate or intermittently elevated alanine aminotransferase levels Influencia de factores virales y del huésped en la actividad histológica en pacientes con hepatitis crónica por virus de la hepatitis B y elevación moderada o intermitente de alanina aminotransferasa

    Directory of Open Access Journals (Sweden)

    E. Molina Pérez

    2010-09-01

    Full Text Available Objective: viral and host factors are related with progression of pathological lesion in chronic hepatitis B. We analyzed these factors in patients with moderate or intermittently elevated ALT levels, and its threshold that determinate significant histological activity. Patients and methods: retrospective analyses of viral and host parameters in 89 consecutive chronic hepatitis B patients biopsied because of moderate or intermittently elevated ALT levels [1-2 x ULN (ULN = 39 IU/mL] and/or DNA-HBV > 2 x 10³ IU/mL in AntiHBe+ patients. It was analyzed age, gender, ALT levels, HBeAg, viral load and genotype. It was considered advanced histological lesion a Knodell Score (KS > 7 and histological lesion indicating treatment, lobular inflammation ≥ 2 or fibrosis ≥ 2 according to Scheuer Classification. Results: KS > 7 and histological lesion indicating treatment was found in 47.8 and 60.7% respectively. It was observed relationship between age, male gender, ALT levels and viral load with histological damage (p ULN (69.1 vs. 47.1%, p = 0.04. There were not significant upper frequencies of advanced lesion when a cut-off of 40 years or DNA-HBV > 2 x 10³ IU/mL viral load or serological status HBeAg was considerate. Histological activity was lesser in genotype D patients than those infected with others genotypes (p Objetivo: analizar factores virales y del huésped relacionados con actividad histológica en un subgrupo de pacientes con hepatitis crónica B y elevación intermitente o moderada de alanina aminotransferasa (ALT, y el umbral que determine daño histológico indicativo de tratamiento. Pacientes y métodos: análisis retrospectivo de parámetros virales y del huésped en 89 pacientes con hepatitis crónica B biopsiados consecutivamente por elevación intermitente o moderada de ALT [1-2 x USN (USN = 39 UI/mL]. Fueron analizados edad, sexo, ALT, HBeAg, carga viral y genotipo. Se consideró como lesion histologica avanzada un Índice de

  16. 慢性间歇性低压低氧抑制线粒体途径介导的代谢综合征大鼠心肌组织细胞凋亡%Chronic intermittent hypobaric hypoxia ameliorates myocardial apoptosis through inhibiting mitochondrial pathway in rats with metabolism syndrome

    Institute of Scientific and Technical Information of China (English)

    袁芳; 李艳青; 滕旭; 周京京; 郭赞; 王昕; 张自伟; 张翼

    2015-01-01

    Aim To confirm the inhibitory effect of chronic intermittent hypobaric hypoxia ( CIHH) on my-ocardial apoptosis induced by metabolism syndrome ( MS) , and to investigate its mechanism. Methods A rat model of MS induced by fructose was used. The blood pressure and the plasma content of glucose, tri-glyceride, cholesterol, and insulin after 12 h fasting were detected. HE stain were used to detect the cardi-ac structure. The TUNEL staining and activity of caspase-3 were used to detect the apoptosis of myocar-dium. The protein expression of Bcl-2 and Bax was detected by Western blot . Results Compared with the control rats, the blood pressure and the plasma content of glucose, triglyceride, cholesterol, and insu-lin were all increased in rats with MS. In rats with MS, the impairment of cardiac structure and the increase of apoptosis were also observed. The protein expression of Bcl-2 was significantly down-regulated, and that of Bax was significantly up-regulated in MS rats. The ratio of Bcl-2/Bax was also significantly decreased. Interest-ingly, CIHH could ameliorate all of the above issues. There was no significant difference between control group and CIHH group. Conclusion CIHH may im-prove the increased apoptosis in rats with MS via inhib-iting the mitochondrial pathway of apoptosis. This stud-y might provide new targets for therapy and the preven-tion of MS patients.%目的:证实CIHH( chronic intermittent hypobaric hypoxi-a, CIHH)具有改善代谢综合征( metabolism syndrome, MS)大鼠心肌细胞凋亡的作用,并探讨其机制。方法10%果糖水喂养SD大鼠(250~300) g 42 d制备MS模型,检测动脉血压以及空腹血糖、胆固醇、甘油三酯和胰岛素含量,HE染色观察心肌结构,TUNEL染色和caspase-3活性测定检测心肌细胞凋亡, Western blot 检测 Bcl-2和 Bax 的蛋白表达水平。结果与正常大鼠比较,果糖喂养大鼠表现出明显的高血压、高血糖、高甘油三脂血症、高胆固醇血症和高胰

  17. Kinetic intermittency in magnetized plasma turbulence

    CERN Document Server

    Teaca, Bogdan; Told, Daniel; Jenko, Frank

    2016-01-01

    We employ magnetized plasma turbulence, described by a gyrokinetic formalism in an interval ranging from the end of the fluid scales to the electron gyroradius, to introduce the first study of kinetic intermittency, in which nonlinear structures formed directly in the distribution functions are analyzed by accounting for velocity space correlations generated by linear (Landau resonance) and nonlinear phase mixing. Electron structures are found to be strongly intermittent and dominated by linear phase mixing, while nonlinear phase mixing dominates the weakly intermittent ions. This is the first time spatial intermittency and linear phase mixing are shown to be self-consistently linked for the electrons and, as the magnetic field follows the intermittency of the electrons at small scales, explain why magnetic islands are places dominated by Landau damping in steady state turbulence.

  18. Intermittent dystonia in Hartnup disease.

    Science.gov (United States)

    Darras, B T; Ampola, M G; Dietz, W H; Gilmore, H E

    1989-01-01

    A 6-month-old girl developed intermittent dystonic posture of the legs and eczematous dermatitis without ataxia. Qualitative and quantitative urine amino acid testing confirmed the diagnosis of Hartnup disease. Cranial computed tomography, electroencephalogram, electromyogram/nerve conduction study, posterior tibial somatosensory evoked potentials, 24-hour electroencephalographic telemetry, and metrizamide myelogram were normal. Spinal fluid hydroxy-indoleacetic acid concentration was less than or equal to 2 S.D. of normal; oral tryptophan loading (70 mg/kg) resulted in a two-fold rise in cerebrospinal fluid 5-hydroxy-indoleacetic acid concentration. Tryptophan administered alone or with nicotinic acid failed to improve the dystonia; however, trihexyphenidyl (1-2 mg/kg/day) dramatically improved it. Hartnup disease should be considered in children with unexplained dystonia. PMID:2712944

  19. Intermittent transport in edge plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, O.E.; Naulin, V.; Nielsen, A.H.; Juul Rasmussen, J. [Association EURATOM-Riso National Laboratory, Optics and Plasma Research, Roskilde (Denmark)

    2004-07-01

    The properties of low-frequency convective fluctuations and transport are investigated for the boundary region of magnetized plasmas. We employ a two-dimensional fluid model for the evolution of the global plasma quantities in a geometry and with parameters relevant to the scrape-off layer of confined toroidal plasmas. Strongly intermittent plasma transport is regulated by self-consistently generated sheared poloidal flows and is mediated by burst ejection of particles and heat from the bulk plasma in the form of blobs. Coarse grained probe signals reveal a highly skewed and flat distribution on short time scales, but tends towards a normal distribution at large time scales. Conditionally averaged signals are in perfect agreement with experimental measurements. (authors)

  20. Anisotropic Intermittency of Magnetohydrodynamic Turbulence

    CERN Document Server

    Osman, K T; Chapman, S C; Hnat, B

    2013-01-01

    A higher-order multiscale analysis of spatial anisotropy in inertial range magnetohydrodynamic turbulence is presented using measurements from the STEREO spacecraft in fast ambient solar wind. We show for the first time that, when measuring parallel to the local magnetic field direction, the full statistical signature of the magnetic and Els\\"asser field fluctuations is that of a non-Gaussian globally scale-invariant process. This is distinct from the classic multi-exponent statistics observed when the local magnetic field is perpendicular to the flow direction. These observations are interpreted as evidence for the weakness, or absence, of a parallel magnetofluid turbulence energy cascade. As such, these results present strong observational constraints on the statistical nature of intermittency in turbulent plasmas.

  1. Metabolic consequences of intermittent hypoxia.

    Science.gov (United States)

    O'Donnell, Christopher P

    2007-01-01

    Insulin resistance is being recognized increasingly as the basis for the constellation of metabolic abnormalities that make up the metabolic syndrome, or Syndrome X. Insulin resistance is also the primary risk factor for the development of type 2 diabetes mellitus, which is currently reaching epidemic proportions by affecting more than 170 million people worldwide. A combination of environmental and genetic factors have led to a dramatic rise in visceral adiposity, the predominant factor causing insulin resistance and type 2 diabetes. Visceral adiposity is also the major risk factor for the development of Sleep Apnea (SA)--an association that has fueled interest in the co-morbidity of SA and the metabolic syndrome, but hampered attempts to ascribe an independent causative role for Sleep Apnea in the development of insulin resistance and type 2 diabetes. Numerous population and clinic-based epidemiologic studies have shown associations, often independent of obesity, between SA (or surrogates such as snoring) and measures of glucose dysregulation or type 2 diabetes. However, treatment of SA with continuous positive airway pressure (CPAP) has not been conclusive in demonstrating improvements in insulin resistance, perhaps due to the overwhelming effects of obesity. Here we show that in lean, otherwise healthy mice that exposure to intermittent hypoxia produced whole-body insulin resistance as determined by the hyperinsulinemic euglycemic clamp and reduced glucose utilization in oxidative muscle fibers, but did not cause a change in hepatic glucose output. Furthermore, the increase in insulin resistance was not affected by blockade of the autonomic nervous system. We conclude that intermittent hypoxia can cause acute insulin resistance in otherwise lean healthy animals, and the response occurs independent of activation of the autonomic nervous system. PMID:18269187

  2. The influence of chronic intermittent hypoxia on insulin function in OSAHS patients%慢性间歇低氧对阻塞性睡眠呼吸暂停低通气综合征患者胰岛素功能的影响

    Institute of Scientific and Technical Information of China (English)

    徐春明; 朱晔涵; 王姝; 黄建安

    2010-01-01

    目的 探讨慢性间歇低氧及继发的氧化应激对OSAHS患者胰岛素抵抗(IR)、胰腺β细胞功能的影响.方法 研究纳入15例单纯性鼾症患者、31例轻中度OSAHS患者及34例重度OSAHS患者.其中单纯性鼾症患者15例,男14例,女1例;轻中度OSAHS患者31例,男29例,女2例;重度OSAHS患者34人,男31例,女3例.所有患者收集一般临床资料,采用多导睡眠仪整晚监测取得夜间睡眠资料.用ELISA法检测8异前列腺素(8-isoprostane)、空腹血胰岛素(FINS),分光光度计法检测谷胱甘肽过氧化物酶(GSH-Px).采用稳态模型胰岛素抵抗指数(HOMA-IR)、FINS评价IR,稳态模型胰腺β细胞功能指数(HOMA-β)评价胰腺β细胞功能.三组数据间的比较采用多个独立样本非参数检验(Kruskal-Wallis H 检验),两两比较采用Nemenyi检验.数据间的相关性采用spearman秩相关分析,采用多元线性回归分析排除数据间的干扰.计数资料采用χ2检验.结果 随着OSAHS病情的加重,3组患者血清8-异前列腺素、GSH-Px、空腹血糖(FBG)、FINS及HOMA-IR整体比较均存在统计学差异(P=0.0034,P0.05).血清氧减指数(ODI)、血氧饱和度0.05).结论 OSAHS特征性的慢性间歇低氧与IR独立相关,与低氧严重程度相比,IR与氧减次数的联系更密切.OSAHS增强的氧化应激与IR独立相关,未发现胰腺β细胞功能和慢性间歇低氧及继发的氧化应激之间存在相关性.%Objective To discuss the influence of chronic intermittent hypoxia and secondum oxidative stress on insulin resistance and the function of Pancreatic β cells in OSAHS patients. Methods 15 patients with primary snoring, 31 patients with light to moderate OSAHS and 34 patients with severe OSAHS were investigated. General clinical data of every patient were collected, while nocturnal data were gained by using PSG with entire night monitor. 8-isoprostane and fasting insulin (FINS) were detected through ELISA; GSH-Px through Spectrophotometer

  3. Analytical approach to continuous and intermittent bottleneck flows

    DEFF Research Database (Denmark)

    Helbing, D.; Johansson, A.; Mathiesen, Joachim Kaj;

    2006-01-01

    Many-particle-inspired theory, Continuous and Intermittent Bottleneck Flows Udgivelsesdato: Oct. 20......Many-particle-inspired theory, Continuous and Intermittent Bottleneck Flows Udgivelsesdato: Oct. 20...

  4. MUSCLE FIBER SPECIFIC ANTIOXIDATIVE SYSTEM ADAPTATION TO SWIM TRAINING IN RATS: INFLUENCE OF INTERMITTENT HYPOXIA

    OpenAIRE

    Olga Gonchar

    2005-01-01

    The aim of the present study was to examine the influence of intermittent hypoxia at rest and in combination with long-term high-intensity swimming exercise on lipid peroxidation and antioxidant defense system adaptation in skeletal muscles differing in fiber type composition. High-intensity chronic exercise was performed as swimming training with load that corresponded to ~ 75 % VO2max (30 min·day-1, 5 days·wk-1, for 4 wk). Intermittent hypoxic training (IHT) consisted of repeated episodes o...

  5. 慢性间歇低氧对大鼠肝细胞IRS-2、 FoxO1表达的影响%Effects of chronic intermittent hypoxia on IRS-2 and FoxO1 expression in rat heptocytes

    Institute of Scientific and Technical Information of China (English)

    李娜娜; 任寿安

    2015-01-01

    .Methods Twenty-four healthy male Sprauge-Dawley rats at 6-week age were divided into normal control group (NC group),chronic intermittent hypoxia for 4 weeks group (CIH4 group) and chronic intermittent hypoxia for 8 weeks group (CIH8 group) according to random number table,with 8 rats in each group.CIH4 group and CIH8 group were placed in intermittent low oxygen cabin for 8 hours per day,the minimum oxygen concentration was 6%-8%.NC group was placed in normal air cabin.Fasting blood glucose and fasting insulin level were measured on 4th week,8th week and after an overnight fast of 12 hours on 8th week in CIH4,CIH8 and NC group,respectively.Homeostatic model assessment of insulin resistance index (HOMA-IR) and insulin sensitive index (ISI) were used to evaluate insulin resistance.HE staining was used for morphologic study of liver.IRS-2 and FoxO1 expression in heptocytes were analyzed by immunohistochemistry.Average gray value was used to represent the protein expression,and which was inversely proportional to average gray value.Results Compared with NC group,CIH4 and CIH8 group had elevated fasting blood glucose,fasting insulin,HOMA-IR,and reduced ISI,especially in CIH8 group (F =50.23-90.26,all P < 0.05).Compared with NC group,the expression of IRS-2 decreased in CIH4 and CIH8 group;the expression of FoxO1 increased in CIH4 and CIH8 group with the re-distribution in the nucleus,especially in CIH8 group (F =69.46,618.94,all P < 0.05).Pearson correlation analysis showed that HOMA-IR was positively correlated with the average gray value of IRS-2 (r =0.857,P < 0.05),but was negatively correlated with the average gray value of FoxO1 (r =-0.926,P < 0.05).ISI was negatively correlated with the average gray value of IRS-2 (r =-0.823,P < 0.05) and was positively correlated with the average gray value of FoxO1 (r=0.848,P<0.05).Conclusions In intermittent hypoxia,the liver is damaged along with the occurrence of insulin resistance and the abnormal expression of IRS-2 and

  6. Experiences of living with intermittent claudication.

    Science.gov (United States)

    Egberg, Louise; Andreassen, Sissel; Mattiasson, Anne-Cathrine

    2012-03-01

    Intermittent claudication is a symptom caused by peripheral arterial disease (PAD) and is associated with pain, impaired mobility and loss of control. Walking ability is reduced due to the pain, and both physical and social functions are often negatively affected, which may lead to patients feeling they are a burden to others. An interview study using a qualitative descriptive design to describe experiences of living with intermittent claudication caused by PAD was carried out during Winter and Spring 2009/2010. Fifteen people suffering from intermittent claudication were interviewed, and the interviews were analyzed using qualitative thematic analysis. Intermittent claudication greatly affects daily living. Six themes were identified: "Experiencing discomfort in the legs," "Moving around in a new way," "Feeling inconvenient when forced to stop," "Missing previous life," "Incorporating intermittent claudication in daily life," and "To lead a strenuous life." The main theme was "Adjusting to a restricted life." The findings show that intermittent claudication has a major impact on daily life. Apart from the severity of symptoms, how the illness is experienced differs among patients, depending on how active the ill person is or wants to be. These findings suggest that increased knowledge about living with intermittent claudication is important to understand the effects on the ill person's life, as a complement to physical examinations when planning individual treatment. PMID:22321401

  7. Intermittency and rough-pipe turbulence

    CERN Document Server

    Mehrafarin, Mohammad

    2008-01-01

    Recently, by analyzing the measurement data of Nikuradze, it has been proposed (N. Goldenfeld, Phys. Rev. Lett. {\\bf{96}}, 044503, 2006) that the friction factor, $f$, of rough pipe flow obeys a scaling law in the turbulent regime. Here, we provide a phenomenological scaling argument to explain this law and demonstrate how intermittency modifies the scaling form, thereby relating $f$ to the intermittency exponent, $\\eta$. By statistically analyzing the measurement data of $f$, we infer a satisfactory estimate for $\\eta$ ($\\approx 0.02$), the inclusion of which is shown to improve the data-collapse curve. This provides empirical evidence for intermittency other than the direct measurement of velocity fluctuations.

  8. Assessing Relative Volatility/Intermittency/Energy Dissipation

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole E.; Pakkanen, Mikko; Schmiegel, Jürgen

    process in particular. While this estimation method is motivated by the assessment of relative energy dissipation in empirical data of turbulence, we apply it also to energy price data. Moreover, we develop a probabilistic asymptotic theory for relative power variations of Brownian semistationary......We introduce the notion of relative volatility/intermittency and demonstrate how relative volatility statistics can be used to estimate consistently the temporal variation of volatility/intermittency even when the data of interest are generated by a non-semimartingale, or a Brownian semistationary...... processes and Ito semimartingales and discuss how it can be used for inference on relative volatility/intermittency....

  9. Influences of chronic intermittent hypoxia on morphology and ultra-structure of renal tissue in the rats%慢性间歇低氧对大鼠肾脏组织细胞形态和超微结构的影响

    Institute of Scientific and Technical Information of China (English)

    邵川; 鲁沈源; 励雯静; 隆玄; 李善群; 白春学

    2011-01-01

    目的 探讨慢性间歇低氧( CIH)对肾脏组织细胞形态和超微结构的影响及其意义.方法 采用自制的CIH动物舱,通过控制程序调节舱内氧气、氮气的输入流量,使得每1次缺氧循环时间为1 min,氧气浓度循环于7%~21%之间.将18只大鼠随机分成2组,每组9只,分别为对照组和CIH组.将CIH组置于动物舱给予间歇缺氧,每天8h,持续35 d.对照组动物舱内输入空气,其余条件同CIH组.HE染色观察肾脏组织细胞形态,透射电镜观察肾近曲小管上皮细胞超微结构.结果 HE染色示对照组肾脏组织形态基本正常,CIH组肾小球高度肿胀,肾球囊狭窄,近曲小管上皮细胞高度肿胀,管腔狭窄.透射电镜观察发现对照组肾脏超微结构基本正常,CIH组肾近曲小管上皮细胞出现空泡变性、核膜肿胀和线粒体肿胀.结论 CIH导致肾脏组织细胞水肿变性和超微结构异常,可能与OSAHS引起肾脏损害有关.%Objective To discuss the influence of chronic intermittent hypoxia (CIH) on morphology and ultra-structure of renal tissue and its significance. Methods The oxygen and nitrogen input flow of the self-made CIH animal cabin could be adjusted through control procedures, so as to make sure the every hypoxic cycle lasted for 1 minute and the oxygen concentration within the cabin fluctuated between 7% - 21 %. 18 rats were randomly divided into control and CIH groups respectively with each of nine. Rats of CIH group were exposed to intermittent hypoxia in the cabin 8 hours per day for successive 35 days. Oxygen and nitrogen were replaced by air for rats of control group with other conditions being the same as CIH group. Tissue morphology of kidney was examined through HE dyeing and ultra-structures of proximal tubular cells were observed by transmission electron microscopy. Results HE staining showed the renal tissue morphology of control group was normal While in CIH group, high degree of swelling of glomerulus and

  10. NF-κB,IL-6 and PGE2 expression in periodontal tissue of rats with periodontitis under chronic intermittent hypoxia%间歇性低氧对牙周炎大鼠牙周组织中 NF-κB、IL-6及 PGE2含量的影响

    Institute of Scientific and Technical Information of China (English)

    王月昊; 王小琴; 苗伟; 柴晶; 程宇钊; 马小雯

    2016-01-01

    Objective:To examine the effects of chronic intermittent hypoxia(CIH)on the NF-κB,IL-6 and PGE2 level in rats with periodontitis.Methods:32 male SD rats(6 weeks old)were randomly divided into 4 groups(n =8),group A(normoxic control),B (normoxic periodontitis),C(CIH)and D(periodontitis +CIH).Periodontitis model was established in the upper second molars by liga-tion technique and high-glucose diet in the rats of group B and D.The rats in the group C and D were subjected to CIH in a cycle of al-ternative nitrogen and oxygen in a closed chamber.The chamber was filled with nadir and zenith ambient oxygen every 1 20 seconds per cycle for 8 hours per day.The rats were sacrificed and the gingival tissues were examined for the detection of IL-6 and PGE2 expression by ELISA,and NF-κB expression by immunohistochemistry.Results:Histology revealed apical migration of junctional epithetlium and crestal alveolar bone resorption in group B and D,and in the above phenomena of group D was the severest.The content of NF-κB,IL-6 and PGE2 in group B,C,D was higher than that in group A(P <0.05),and in group D was the highest(P <0.05).Conclusion:Chro-nic intermittent hypoxia can aggravate the inflammation of periodontitis.%目的:建立慢性间歇性低氧(CIH)及牙周炎大鼠模型,研究 NF-κB、IL-6及 PGE2水平的变化。方法:将32只普通级6周龄雄性 SD 大鼠随机分为4组(n =8):A:常氧空白组、B:常氧牙周炎组、C:CIH 组、D:CIH 合并牙周炎组。B、D 组大鼠上颌第二磨牙进行结扎处理,辅以高糖饮食;A、C 组正常饮食。C、D 组置于低氧舱8 h/d。8周后处死,HE 染色,免疫组化检测牙周组织 NF-κB 含量,ELISA 检测牙龈组织 IL-6、PGE2。结果:HE 染色:8周后 B 组、D 组牙周炎症表现明显。免疫组化:B、C、D 组 NF-κB 表达均高于 A 组(P <0.05);ELISA 检测:B、C、D 组 IL-6、PGE2含量高于 A 组(P <0.05),且 D 组 IL-6

  11. 慢性间歇低氧对大鼠肝脏的损伤及4-羟基-2,2,6,6-四甲基哌啶的干预作用%Hepatic injury in rats exposed to chronic intermittent hypoxia and the effect of tempol

    Institute of Scientific and Technical Information of China (English)

    姜秋芳; 陈宝元; 董丽霞; 林慧; 孔铖英; 张静; 郑立文

    2012-01-01

    Objective To investigate the mechanism of liver injury in rats exposed to chronic intermittent hypoxia (CIH) and to investigate the effect of tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl or 4-hydroxy-TEMPO).Methods A CIH animal model of rats was established to mimic the intermittent hypoxia/re-oxygenation(IH/ROX) of obstructive sleep apnea syndrome in humans.Thirty-two healthy male Wistar rats were randomly assigned to 4 groups:conventional intermittent hypoxia group( CIH group),intermittent hypoxia Tempol treatment group ( CIH + T group),intermittent hypoxia normal saline matched group( CIH + NS group),and normoxic control group( NC group),with 8 rats in each group.The frequency of every CIH group was 30 times/h,and the minimum oxygen concentration was 5%.After the experiment,sections of liver were stained with hematoxylin-eosin ( HE ) and the levels of nuclear factor-kappaB (NF-tcB),glutathione peroxidase (GSH-PX) and malondialdehyde (MDA) in rat liver homogenate were measured.Results Liver histology revealed that the C1H group and the CIH + NS group showed hepatocellular swelling with rarefaction of the cytoplasm,hyperchromatosis and hepatocellular membrane disruption,but the liver histology of the CIH + T group and the NC group was normal.Compared with the NC group,the levels of NF-κB and MDA in the CIH group [ (12.4 ±2.0) ng/g,(101 +22) μ,mol/g]and the CIH + NS group [ ( 12.2 ± 1.9 ) ng/g,( 99 ± 18 ) μmol/g] were increased( all P < 0.05 ),but the activities of GSH-PX [ ( 88 ± 17 ) U/mg,(90 + 15 ) U/mg ] were decreased ( all P < 0.05 ).Compared with the CIH + NS group and the CIH group,the activity of GSH-PX in the CIH + T group [ ( 181 + 29 ) U/mg ]was increased(P <0.05),but the levels of NF-κB [ (7.8 ± 1.3) ng/g] and MDA [ (59 ± 10) μmol/g]were decreased(all P < 0.05 ).The levels of GSH-PX and MDA in the CIH + T group were not significantly different compared to the NC group ( P were 0.242,0.177 respectively),but the level of NF

  12. Intermittent sea-level acceleration

    Science.gov (United States)

    Olivieri, M.; Spada, G.

    2013-10-01

    Using instrumental observations from the Permanent Service for Mean Sea Level (PSMSL), we provide a new assessment of the global sea-level acceleration for the last ~ 2 centuries (1820-2010). Our results, obtained by a stack of tide gauge time series, confirm the existence of a global sea-level acceleration (GSLA) and, coherently with independent assessments so far, they point to a value close to 0.01 mm/yr2. However, differently from previous studies, we discuss how change points or abrupt inflections in individual sea-level time series have contributed to the GSLA. Our analysis, based on methods borrowed from econometrics, suggests the existence of two distinct driving mechanisms for the GSLA, both involving a minority of tide gauges globally. The first effectively implies a gradual increase in the rate of sea-level rise at individual tide gauges, while the second is manifest through a sequence of catastrophic variations of the sea-level trend. These occurred intermittently since the end of the 19th century and became more frequent during the last four decades.

  13. Improved Intermittency Analysis of Single Event Data

    OpenAIRE

    Janik, R. A.; Ziaja, B.

    1998-01-01

    The intermittency analysis of single event data (particle moments) in multiparticle production is improved, taking into account corrections due to the reconstruction of history of a particle cascade. This approach is tested within the framework of the $\\alpha$-model.

  14. Scalings of intermittent structures in magnetohydrodynamic turbulence

    CERN Document Server

    Zhdankin, Vladimir; Uzdensky, Dmitri A

    2016-01-01

    Turbulence is ubiquitous in plasmas, leading to rich dynamics characterized by irregularity, irreversibility, energy fluctuations across many scales, and energy transfer across many scales. Another fundamental and generic feature of turbulence, although sometimes overlooked, is the inhomogeneous dissipation of energy in space and in time. This is a consequence of intermittency, the scale-dependent inhomogeneity of dynamics caused by fluctuations in the turbulent cascade. Intermittency causes turbulent plasmas to self-organize into coherent dissipative structures, which may govern heating, diffusion, particle acceleration, and radiation emissions. In this paper, we present recent progress on understanding intermittency in incompressible magnetohydrodynamic turbulence with a strong guide field. We focus on the statistical analysis of intermittent dissipative structures, which occupy a small fraction of the volume but arguably account for the majority of energy dissipation. We show that, in our numerical simulat...

  15. On-line intermittent connector anomaly detection

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper investigates a non-traditional use of differential current sensor and current sensor to detect intermittent disconnection problems in connectors. An...

  16. Insights from Intermittent Binocular Rivalry and EEG

    OpenAIRE

    Pitts, Michael A.; Juliane eBritz

    2011-01-01

    Novel stimulation and analytical approaches employed in EEG studies of ambiguous figures have recently been applied to binocular rivalry. The combination of intermittent stimulus presentation and EEG source imaging has begun to shed new light on the neural underpinnings of binocular rivalry. Here, we review the basics of the intermittent paradigm and highlight methodological issues important for interpreting previous results and designing future experiments. We then outline current analytical...

  17. Intermittent cyclophosphamide in refractory rheumatoid arthritis

    OpenAIRE

    Hørslev-Petersen, Kim; Beyer, Jannie M; Helin, Pekka

    1983-01-01

    Three patients with refractory rheumatoid arthritis were treated with oral cyclophosphamide; in two cases this was supplemented with pulse treatment with methylprednisolone. Long term remission was induced in all three patients and was sustained until follow up at least nine months after the methylprednisolone was stopped. Leucopenia occurred but resolved when cyclophosphamide was reduced from daily to intermittent dosing. Intermittent treatment with cyclophosphamide, possibly in conjunction ...

  18. Scalings of intermittent structures in magnetohydrodynamic turbulence

    Science.gov (United States)

    Zhdankin, Vladimir; Boldyrev, Stanislav; Uzdensky, Dmitri A.

    2016-05-01

    Turbulence is ubiquitous in plasmas, leading to rich dynamics characterized by irregularity, irreversibility, energy fluctuations across many scales, and energy transfer across many scales. Another fundamental and generic feature of turbulence, although sometimes overlooked, is the inhomogeneous dissipation of energy in space and in time. This is a consequence of intermittency, the scale-dependent inhomogeneity of dynamics caused by fluctuations in the turbulent cascade. Intermittency causes turbulent plasmas to self-organize into coherent dissipative structures, which may govern heating, diffusion, particle acceleration, and radiation emissions. In this paper, we present recent progress on understanding intermittency in incompressible magnetohydrodynamic turbulence with a strong guide field. We focus on the statistical analysis of intermittent dissipative structures, which occupy a small fraction of the volume but arguably account for the majority of energy dissipation. We show that, in our numerical simulations, intermittent structures in the current density, vorticity, and Elsässer vorticities all have nearly identical statistical properties. We propose phenomenological explanations for the scalings based on general considerations of Elsässer vorticity structures. Finally, we examine the broader implications of intermittency for astrophysical systems.

  19. Assessment of intermittent trace element pollution by moss bags

    Energy Technology Data Exchange (ETDEWEB)

    Cesa, M. [Dipartimento di Biologia, Universita di Trieste, Via Giorgieri 10, I-34127 Trieste (Italy)]. E-mail: mcesa@units.it; Bizzotto, A. [ARPAV Dipartimento di Vicenza, Servizio Territoriale di Bassano del Grappa, Via Cereria 15, I-36061 Bassano del Grappa (VI) (Italy); Ferraro, C. [ARPAV Dipartimento di Vicenza, Servizio Territoriale di Bassano del Grappa, Via Cereria 15, I-36061 Bassano del Grappa (VI) (Italy); Fumagalli, F. [Dipartimento di Biologia, Universita di Trieste, Via Giorgieri 10, I-34127 Trieste (Italy); Nimis, P.L. [Dipartimento di Biologia, Universita di Trieste, Via Giorgieri 10, I-34127 Trieste (Italy)

    2006-12-15

    Moss bags of the aquatic bryophyte Rhynchostegium riparioides (Hedw.) C. Jens. were transplanted into an irrigation ditch in the Province of Vicenza (NE Italy), affected by intermittent trace element contamination due to galvanics. The study aimed at: (a) testing the ability of mosses to detect different patterns of pollution (b) providing information about intensity and temporal extension of pollution events, and (c) localising the main sources. Moss bags were collected after 20, 34, 48 and 62 days of exposure. The concentrations of As, Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn in the desiccated apical shoots of mosses were determined by atomic absorption spectrophotometry. The mean concentrations measured in non-contaminated stations of a previous work were adopted as background values, to calculate the contamination factor (CF). Transplants were able to: (a) detect spatial patterns of bioaccumulation (b) reveal chronic contamination by Pb and Cu, intermittent contamination by Cr, Zn, and Ni, and a release of Cd by moss bags, and (c) localise the main emission sources. - Transplanted bryophytes are able to detect accidental trace element pollution in freshwaters of industrial areas.

  20. Role of hippocampal neuronal intracellular calcium overload in modulating cognitive dysfunction and the neuronprotective effect of mematine in a mouse model of chronic intermittent hypoxia%海马神经元细胞内钙超载对慢性间歇低氧小鼠认知功能的损伤及盐酸美金刚的保护作用

    Institute of Scientific and Technical Information of China (English)

    明红; 陈锐; 王婧; 琚静美; 孙丽; 张国兴

    2014-01-01

    Objective To investigate the role of hippocampal intracellular calcium overload in modulating cognitive dysfunction and the neuronprotective effect of mematine in a mouse model of chronic intermittent hypoxia.Methods 45 ICR male mice were randomly divided into 3 groups:the unhandled control group (UC group,n =15),the chronic intermittent hypoxia (CIH group,n =15) and the pretreatment memantine group (MEM group,n =15).CIH and MEM mice were subjected to intermittent hypoxia while UC mice to room air for 8 h per day during 4 weeks.Mice in the MEM group were pretreated with memantine (5 mg/kg) by intraperitoneal injection before the cycle started,and those in the UC group and the CIH group were treated with same volume of physiological saline.Neurobehavioral assessments were performed by Open filed and Morris water maze,[Ca2+] i in hippocampal neurons was evaluate by flow cytometry,and the expression of cleaved caspase-3,phospho-ERK1/2 in hippocampus were detected by Western blotting.Results Compared with the UC group,CIH mice displayed markedly more locomotor activity (P < 0.05) in Open filed test,longer mean escape latency (P < 0.05),less number of times of crossing the platform (P <0.01) and less percentage of time in target quadrant (P <0.01).Furthermore,exposure to CIH enhanced [Ca2+]i (vs.UC mice,155 ±12 vs.92 ±8,P<0.01),and up-regulated the expression of cleaved caspase-3 (P < 0.01),but down-regulated the level of phospho-ERK1/2 (P < 0.05) in the hippocampus.Pre-treatment with memantine significantly decreased hyperlocomotion (P < 0.05),attenuated memory deficit (P < 0.05),mitigated [Ca2 +] i (vs.CIH mice,90 ± 8 vs.155 ± 12,P < 0.01),decrease the expression of cleaved caspase-3 (P < 0.01),but increased the level of phosphoERK1/2(P < 0.05) comparing to the CIH group.Conclusion The neurobehavioral impairments induced by CIH are mediated,at least in part,by intracellular calcium concentration overload,neuron apoptosis

  1. Chronic penile strangulation

    Directory of Open Access Journals (Sweden)

    Lopes Roberto I

    2003-01-01

    Full Text Available Chronic penile strangulation is exceedingly rare with only 5 cases previously reported. We report an additional case of progressive penile lymphedema due to chronic intermittent strangulation caused by a rubber band applied to the penile base for 6 years. A 49-year-old man presented incapacity to exteriorize the glans penis. For erotic purposes, he had been using a rubber-enlarging band placed in the penile base for 6 years. With chronic use, he noticed that his penis swelled. Physical examination revealed lymphedema of the penis, phimosis and a stricture in the penile base. The patient was submitted to circumcision and the lymphedema remained stable 10 months postoperatively. Chronic penile incarceration usually causes penile lymphedema and urinary disturbance. Treatment consists of removal of foreign devices and surgical treatment of lymphedema.

  2. Intermittency in 2D soap film turbulence

    CERN Document Server

    Cerbus, R T

    2013-01-01

    The Reynolds number dependency of intermittency for 2D turbulence is studied in a flowing soap film. The Reynolds number used here is the Taylor microscale Reynolds number R_{\\lambda}, which ranges from 20 to 800. Strong intermittency is found for both the inverse energy and direct enstrophy cascades as measured by (a) the pdf of velocity differences P(\\delta u(r)) at inertial scales r, (b) the kurtosis of P(\\partial_x u), and (c) the scaling of the so-called intermittency exponent \\mu, which is zero if intermittency is absent. Measures (b) and (c) are quantitative, while (a) is qualitative. These measurements are in disagreement with some previous results but not all. The velocity derivatives are nongaussian at all R_{\\lambda} but show signs of becoming gaussian as R_{\\lambda} increases beyond the largest values that could be reached. The kurtosis of P(\\delta u(r)) at various r indicates that the intermittency is scale dependent. The structure function scaling exponents also deviate strongly from the Kraichn...

  3. [Chronic inflammatory bowel diseases in cats].

    Science.gov (United States)

    Ghermai, A K

    1989-01-01

    The aetiology of chronic idiopathic intestinal inflammation is unknown. It is characterized by a diffuse infiltration with inflammatory cells into the intestinal mucosa and sometimes submucosa. Cats with chronic intermittent vomiting and diarrhoea, later on accompanied by anorexia and weight loss, are presented. Definitive diagnosis can be obtained by intestinal biopsy only. An immune pathogenesis is suspected, which is supported by the fact, that chronic inflammatory bowel disease responds to steroid therapy.

  4. Intermittent hypoendorphinaemia in migraine attack.

    Science.gov (United States)

    Baldi, E; Salmon, S; Anselmi, B; Spillantini, M G; Cappelli, G; Brocchi, A; Sicuteri, F

    1982-06-01

    Beta-endorphin (RIA method, previous chromatographic extraction) was evaluated in plasma of migraine sufferers in free periods and during attacks. Decreased levels of the endogenous opioid peptide were found in plasma sampled during the attacks but not in free periods. Even chronic headache sufferers exhibited significantly lowered levels of beta-endorphin, when compared with control subjects with a negative personal and family history of head pains. The mechanism of the hypoendorphinaemia is unknown: lowered levels of the neuropeptide, which controls nociception, vegetative functions and hedonia, could be important in a syndrome such as migraine, characterized by pain, dysautonomia and anhedonia. The impairment of monoaminergic synapses ("empty neuron" condition) constantly present in sufferers from serious headaches, could be due to the fact that opioid neuropeptides, because of a receptoral or metabolic impairment, poorly modulate the respective monoaminergic neurons, resulting in imbalance of synaptic neurotransmission. PMID:6290072

  5. Magnetic field generation by intermittent convection

    CERN Document Server

    Chertovskih, R; Chimanski, E V

    2016-01-01

    Magnetic field generation by convective flows in transition to weak turbulence is studied numerically. By fixing the Prandtl number at P=0.3 and varying the Rayleigh number (Ra) as a control parameter in three-dimensional Rayleigh-Benard convection of an electrically conducting fluid, a recently reported route to hyperchaos involving quasiperiodic regimes, crises and chaotic intermittent attractors is followed, and the critical magnetic Prandtl number ($P_m^c$) for dynamo action is determined as a function of Ra. A mechanism for the onset of on-off intermittency in the magnetic energy is described, the most beneficial convective regimes for dynamo action are identified, and how intermittency affects the dependence of $P_m^c$ on Ra is discussed.

  6. Intermittency and rough-pipe turbulence.

    Science.gov (United States)

    Mehrafarin, Mohammad; Pourtolami, Nima

    2008-05-01

    Recently, by analyzing the measurement data of Nikuradze [NACA Tech. Memo No. 1292 (1950)], it has been proposed [N. Goldenfeld, Phys. Rev. Lett. 96, 044503 (2006)] that the friction factor, f , of rough-pipe flow obeys a scaling law in the turbulent regime. Here, we provide a phenomenological scaling argument to explain this law and demonstrate how intermittency modifies the scaling form, thereby relating f to the intermittency exponent, eta . By statistically analyzing the measurement data of f , we infer a satisfactory estimate for eta ( approximately 0.02) , the inclusion of which is shown to improve the data-collapse curve. This provides empirical evidence for intermittency other than the direct measurement of velocity fluctuations.

  7. Chaos synchronization based on intermittent state observer

    Institute of Scientific and Technical Information of China (English)

    Li Guo-Hui; Zhou Shi-Ping; Xu De-Ming

    2004-01-01

    This paper describes the method of synchronizing slave to the master trajectory using an intermittent state observer by constructing a synchronizer which drives the response system globally tracing the driving system asymptotically. It has been shown from the theory of synchronization error-analysis that a satisfactory result of chaos synchronization is expected under an appropriate intermittent period and state observer. Compared with continuous control method,the proposed intermittent method can target the desired orbit more efficiently. The application of the method is demonstrated on the hyperchaotic Rossler systems. Numerical simulations show that the length of the synchronization interval rs is of crucial importance for our scheme, and the method is robust with respect to parameter mismatch.

  8. Dynamics of desynchronized episodes in intermittent synchronization

    Directory of Open Access Journals (Sweden)

    Leonid L Rubchinsky

    2014-06-01

    Full Text Available Intermittent synchronization is observed in a variety of different experimental settings in physics and beyond and is an established research topic in nonlinear dynamics. When coupled oscillators exhibit relatively weak, intermittent synchrony, the trajectory in the phase space spends a substantial fraction of time away from a vicinity of a synchronized state. Thus to describe and understand the observed dynamics one may consider both synchronized episodes and desynchronized episodes (the episodes when oscillators are not synchronous. This mini-review discusses recent developments in this area. We explain how one can consider variation in synchrony on the very short time-scales, provided that there is some degree of overall synchrony. We show how to implement this approach in the case of intermittent phase locking, review several recent examples of the application of these ideas to experimental data and modeling systems, and discuss when and why these methods may be useful.

  9. Assessing relative volatility/intermittency/energy dissipation

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole E.; Pakkanen, Mikko S.; Schmiegel, Jürgen

    2014-01-01

    process in particular. This estimation method is motivated by the assessment of relative energy dissipation in empirical data of turbulence, but it is also applicable in other areas. We develop a probabilistic asymptotic theory for realised relative power variations of Brownian semistationary processes......, and introduce inference methods based on the theory. We also discuss how to extend the asymptotic theory to other classes of processes exhibiting stochastic volatility/intermittency. As an empirical application, we study relative energy dissipation in data of atmospheric turbulence.......We introduce the notion of relative volatility/intermittency and demonstrate how relative volatility statistics can be used to estimate consistently the temporal variation of volatility/intermittency when the data of interest are generated by a non-semimartingale, or a Brownian semistationary...

  10. Intermittent versus continuous androgen deprivation therapy.

    Science.gov (United States)

    Higano, Celestia S

    2014-05-01

    Androgen deprivation therapy (ADT) has been the standard of care for metastatic prostate cancer for decades; however, the choice of continuous or intermittent administration is a matter of debate. Two large phase III trials have reported results comparing these 2 forms of ADT administration. The National Cancer Institute of Canada (NCIC) PR-7 trial studied men with an increasing prostate-specific antigen (PSA) level and no evidence of metastatic disease after definitive or salvage radiation therapy and radical prostatectomy. The Southwest Oncology Group 9346 trial studied men with newly diagnosed hormone-sensitive metastatic disease. The primary end point in both trials was overall survival with a noninferiority design. The NCIC trial showed that the overall survival in men treated with intermittent ADT was not inferior to that of men treated with continuous ADT, but the SWOG trial was inconclusive regarding noninferiority. Certain domains of quality of life were better in the intermittent arms of both trials. If using ADT in the setting of biochemical relapse, intermittent ADT should be strongly considered over continuous ADT, except perhaps in patients with Gleason score of 8 or higher. In men with metastatic disease, continuous ADT remains the standard of care, because the SWOG trial did not establish noninferiority of intermittent ADT with respect to survival. However, for those with significant side effects from ADT, establishing the risk group, as determined by PSA value after 7 months of ADT or the presence of pain at diagnosis, may help guide the choice of intermittent versus continuous ADT in men with metastatic disease. PMID:24812139

  11. Intermittent heat exposure and thirst in rats

    OpenAIRE

    Barney, Christopher C.; Kuhrt, David M.

    2016-01-01

    Abstract Adequate water intake, supporting both cardiovascular function and evaporative cooling, is a critical factor in mitigating the effects of heat waves, which are expected to increase with global warming. However, the regulation of water intake during periods of intermittent heat exposure is not well understood. In this study, the effects of access to water or no access during intermittent heat exposure were assessed using male Sprague‐Dawley rats exposed to 37.5°C for 4 h/day. After 7 ...

  12. Intermittently connected mobile ad hoc networks

    CERN Document Server

    Jamalipour, Abbas

    2011-01-01

    In the last few years, there has been extensive research activity in the emerging area of Intermittently Connected Mobile Ad Hoc Networks (ICMANs). By considering the nature of intermittent connectivity in most real word mobile environments without any restrictions placed on users' behavior, ICMANs are eventually formed without any assumption with regard to the existence of a end-to-end path between two nodes wishing to communicate. It is different from the conventional Mobile Ad Hoc Networks (MANETs), which have been implicitly viewed as a connected graph with established complete paths betwe

  13. Intermittent hypoxia with or without hypercapnia is associated with tumorigenesis by decreasing the expression of brain derived neurotrophic factor and miR-34a in rats

    Institute of Scientific and Technical Information of China (English)

    Zhang Jing; Guo Xu; Shi Yanwei; Ma Jing; Wang Guangfa

    2014-01-01

    Background Very recent studies revealed that obstructive sleep apnoea (OSA) is a contributor of the increased incidence and mortality of cancer in humans,but mechanisms of how OSA promotes tumorigenesis remains largely unknown.We investigated whether intermittent hypoxia with and without hypercapnia plays a role in tumorigenesis.Methods First,Sprague-Dawley (SD) male rats (12 weeks old) were subjected to different hypoxia exposures:intermittent hypoxia and intermittent hypoxia with hypercapnia; continuous hypoxia and normal air.The systemic application of chronic fast rate hypoxia with or without hypercapnia mimicked severe OSA patients with apnoea/hypopnea index equivalent to 60 events per hour.Then routine blood tests were performed and the levels of brain derived neurotrophic factor (BDNF) and miR-34a were examined.Results In contrast to intermittent hypoxia with hypercapnia,both intermittent hypoxia and continuous hypoxia treatments caused significantly higher levels of haematology parameters than normoxia treatments.Compared to normoxia,intermittent hypoxia with hypercapnia exposure resulted in substantial decrease of serum BDNF and,miR-34a in the lower brainstem,while less pronounced results were found in intermittent hypoxia and continuous hypoxia exposure.Conclusions The exposure of intermittent hypoxia with or without hypercapnia,mimicking the situations in severe OSA patients,was associated with,or even promoted tumorigenesis.

  14. Effects of chronic intermittent hypoxia on the cognitive function and neuron structure of hippocampus in mouse model of Parkinson's disease%慢性间断性缺氧对帕金森病模型小鼠认知功能及海马神经元结构的影响

    Institute of Scientific and Technical Information of China (English)

    刘海林; 宋永斌; 张子彦; 李景春; 徐江涛

    2013-01-01

    Objective To investigate the effects of chronic intermittent hypoxia (CIH) on the cognitive function,neuron structure and synaptophysin (Syn) expression of the hippocampus in mouse model of Parkinson's disease (PD).Methods A hypoxia-reoxygen device was used to prepare the model of CIH.Meanwhile,the PD mouse model was built by intraperitoneal injection of paraquat (PQ).The cognitive function was evaluated by Y-type electric maze and step-down test.Syn expression in the hippocampus was estimated by immunohistochemistry.The neuron structure in the hippocampus was observed by HE staining,Nissl staining and the electron microscope.Results Comparing to control group,a significant decrease was found in learning and memorizing performance (P < 0.05,for all) and the amount of neuron,while a significant increase was seen in total reaction time (TRT) and error reaction (ER) in Y-type electric maze and step-down test and the gray value of Syn in the hippocampus in PQ,CIH,and PQ + CIH groups.Various degrees of anomaly were observed in neuron structure of hippocampus by HE staining,Nissl staining and electron microscopy in PQ,CIH,and PQ + CIH groups,while presented most obviously in the latter group.Conclusion The PQ-induced impairment of cognitive function in PD model mice was aggravated by CIH,which may be related to the damage of neuron structure and the decrease of synaptic function in hippocampus.%目的 探讨慢性间断性缺氧对帕金森病模型小鼠认知功能、海马神经元结构及突触素表达水平的影响.方法 采用百草枯腹腔注射联合慢性间断性缺氧制备帕金森病伴睡眠障碍小鼠模型,通过电迷宫和跳台实验评价其学习和记忆能力,HE和Nissl染色观察海马神经元形态及数目变化、免疫组织化学染色检测海马神经元突触素表达水平、电子显微镜观察海马神经元超微结构.结果 与对照组比较,百草枯组、慢性间断性缺氧组及其联合组小鼠学习和

  15. Intermittent demand : Linking forecasting to inventory obsolescence

    NARCIS (Netherlands)

    Teunter, Ruud H.; Syntetos, Aris A.; Babai, M. Zied

    2011-01-01

    The standard method to forecast intermittent demand is that by Croston. This method is available in ERP-type solutions such as SAP and specialised forecasting software packages (e.g. Forecast Pro), and often applied in practice. It uses exponential smoothing to separately update the estimated demand

  16. Current drive induced by intermittent trapping

    Energy Technology Data Exchange (ETDEWEB)

    Nakach, R. [Association Euratom-CEA, CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee (DRFC), 13 - Saint-Paul-lez-Durance (France); Gell, Y. [CET, Israel (Israel)

    1999-02-01

    We propose a mechanism for driving a current in a dispersive plasma based on intermittent trapping of electrons in a ponderomotive well generated by two- counterpropagating electron cyclotron waves. By choosing properly the parameters of the system, this mechanism is expected to induce a high efficiency current drive. (authors)

  17. Temporal and spatial intermittencies within Newtonian turbulence

    Science.gov (United States)

    Kushwaha, Anubhav; Graham, Michael

    2015-11-01

    Direct numerical simulations of a pressure driven turbulent flow are performed in a large rectangular channel. Intermittent high- and low-drag regimes within turbulence that have earlier been found to exist temporally in minimal channels have been observed both spatially and temporally in full-size turbulent flows. These intermittent regimes, namely, ''active'' and ''hibernating'' turbulence, display very different structural and statistical features. We adopt a very simple sampling technique to identify these intermittent intervals, both temporally and spatially, and present differences between them in terms of simple quantities like mean-velocity, wall-shear stress and flow structures. By conditionally sampling of the low wall-shear stress events in particular, we show that the Maximum Drag Reduction (MDR) velocity profile, that occurs in viscoelastic flows, can also be approached in a Newtonian-fluid flow in the absence of any additives. This suggests that the properties of polymer drag reduction are inherent to all flows and their occurrence is just enhanced by the addition of polymers. We also show how the intermittencies within turbulence vary with Reynolds number. The work was supported by AFOSR grant FA9550-15-1-0062.

  18. Aggression induced by intermittent positive reinforcement.

    Science.gov (United States)

    Looney, T A; Cohen, P S

    1982-01-01

    Mammalian and non-mammalian species engage in aggressive behavior toward animate and inanimate targets when exposed to intermittent access to a positive reinforcer. This behavior, called extinction- or schedule-induced aggression, typically includes a biting or striking topography that inflicts damage on a target. This paper critically reviews research and theoretical issues concerning such aggression and suggests directions for future investigation.

  19. An Elderly Woman With Intermittent Claudication

    OpenAIRE

    Wazir, Nayyer Naveed

    2006-01-01

    This case report illustrates the misdiagnosis of intermittent claudication in an elderly with multiple cardiac risk factors. Careful clinical evaluation and imaging shifts the diagnosis from peripheral vascular disease to spinal stenosis. The decision whether to offer conservative therapy or proceed to spinal surgery requires an accurate assessment of the severity of the symptoms without ignoring the important role of patient preferences.

  20. Effects of Intermittent Pneumatic Compression on Reduction of Postoperative Lower Extremity Edema and Normalization of Foot Microcirculation Flow in Patients Undergoing Arterial Revascularization

    OpenAIRE

    Pawlaczyk, Katarzyna; Gabriel, Marcin; Urbanek, Tomasz; Dzieciuchowicz, Łukasz; Krasiński, Zbigniew; Gabriel, Zofia; Olejniczak-Nowakowska, Małgorzata; Stanisić, Michał

    2015-01-01

    Background In patients with chronic leg ischemia, the beneficial effect of arterial revascularization can be significantly decreased due to postoperative leg swelling. The aim of this study was to assess the effects of intermittent pneumatic compression (IPC) on skin flow normalization in patients undergoing revascularization procedures due to chronic leg ischemia. Material/Methods We evaluated 116 patients with chronic leg ischemia. The patients were divided into groups according to the perf...

  1. Chronic pancreatitis

    Science.gov (United States)

    Chronic pancreatitis - chronic; Pancreatitis - chronic - discharge; Pancreatic insufficiency - chronic; Acute pancreatitis - chronic ... abuse over many years. Repeated episodes of acute pancreatitis can lead to chronic pancreatitis. Genetics may be ...

  2. Intermittent Aeration in Biological Treatment of Wastewater

    Directory of Open Access Journals (Sweden)

    H. Doan

    2009-01-01

    Full Text Available Problem statement: E-coating process is widely used to provide a protective coating layer on metal parts in the automotive and metal finishing industry. The wastewater from the coating process contains organic compounds that are used in the cleaning, pretreatment and coating steps. Organic pollutants can be removed biologically. In the aerobic biological treatment, water aeration accounts for a significant portion of the total operating cost of the treatment process. Intermittent aeration is thus of benefit since it would reduce the energy consumption in the wastewater treatment. In the present study, wastewater from an electro-coating process was treated biologically using a packed column as an aerator where the wastewater was aerated by a countercurrent air flow. The objective was to obtain an optimum aeration cycle. Approach: Intermittent aeration time was varied at different preset cycles. An operational optimum of the aeration time (or air-water contacting time in the column was determined from the BOD5 removal after a certain treatment period. For continuous aeration of the wastewater, the air-liquid contacting time in the column was 52 min for 24 h of treatment. A unit energy consumption for pumping liquid and air, which was defined as the energy consumption per percent BOD5 removed, was used as a criterion to determine the optimum contacting time. Results: Optimum air-liquid contacting times were found to be about 38, 26 and 22 min for the treatment times of 24, 48 and 72 h, consecutively. This indicates that 27-58% saving on the unit energy consumption can be achieved using intermittent aeration of the wastewater. On the basis of the overall BOD5 removal, 17% and 23% savings in energy were observed with the intermittent aeration as compared to the continuous aeration of the wastewater for 48 and 72 h. Conclusion: The results obtained indicate that an appropriate intermittent aeration cycle can bring about a substantial energy saving

  3. Intermittent heat exposure and thirst in rats.

    Science.gov (United States)

    Barney, Christopher C; Kuhrt, David M

    2016-04-01

    Adequate water intake, supporting both cardiovascular function and evaporative cooling, is a critical factor in mitigating the effects of heat waves, which are expected to increase with global warming. However, the regulation of water intake during periods of intermittent heat exposure is not well understood. In this study, the effects of access to water or no access during intermittent heat exposure were assessed using male Sprague-Dawley rats exposed to 37.5°C for 4 h/day. After 7 days of intermittent heat exposure, reductions in evaporative water loss were observed in all animals and reductions in water intake following heat exposure occurred as the days of heat exposure increased. Rats that were not allowed water during the 7 days of exposure had decreased rehydration levels, however, rats allowed access to water increased water intake during exposure and exhibited higher overall rehydration levels over the same time period. Peripheral administration of angiotensinII, mimicking activation of volemic thirst, or hypertonic saline solution, activating intracellular thirst, did not result in alteration of water intake in rats exposed to heat with access to water compared to control rats. In contrast, rats exposed to heat without access to water had reduced water intake after administration of hypertonic saline and increased water intake after administration of angiotensinIIcompared to control rats. These experiments demonstrate that thirst responses to intermittent heat exposure are altered by providing water during heat exposure and that intermittent heat exposure without access to water alters drinking responses to both intracellular and extracellular thirst challenges. PMID:27095836

  4. An update of clinical management of acute intermittent porphyria

    Directory of Open Access Journals (Sweden)

    Pischik E

    2015-09-01

    mutation-positive family members. C, management of patients with recurrent attacks: 1 evaluation of the lifestyle, 2 evaluation of hormonal therapy in women, 3 prophylactic heme therapy, and 4 liver transplantation in patients with severe recurrent attacks. D, follow-up of the AIP patients for long-term complications: chronic hypertension, chronic kidney insufficiency, chronic pain syndrome, and hepatocellular carcinoma. Keywords: porphyria, acute intermittent porphyria, neuropathy, treatment, heme

  5. INTERMITTENCY AND SCALING IN TURBULENT CONVECTION

    Institute of Scientific and Technical Information of China (English)

    Emily S. C. CHING

    2003-01-01

    Both the velocity and temperature measurements taken in turbulent Rayleigh-B'enard convection experiments have been analyzed. It is found that both the velocity and temperature fluctuations are intermittent and can be well-described by the She-Leveque hierarchical structure. A positive correlation between the vertical velocity and the temperature differences is found both at the center,near the sidewall and near the bottom of the convection cell, supporting that buoyancy is significant in the Bolgiano regime. Moreover, the intermittent nature of the temperature fluctuations in the Bolgiano regime can be attributed to the variations in the temperature dissipation rate. However, the relations between the velocity and temperature structure functions and their correlations implied by the Bolgiano-Obukhov scaling are not supported by experimental measurements.

  6. Insights from intermittent binocular rivalry and EEG

    Directory of Open Access Journals (Sweden)

    Michael A Pitts

    2011-09-01

    Full Text Available Novel stimulation and analytical approaches employed in EEG studies of ambiguous figures have recently been applied to binocular rivalry. The combination of intermittent stimulus presentation and EEG source imaging has begun to shed new light on the neural underpinnings of binocular rivalry. Here, we review the basics of the intermittent paradigm and highlight methodological issues important for interpreting previous results and designing future experiments. We then outline current analytical approaches, including EEG microstates, event-related potentials, and statistically-based source estimation, and propose a spatio-temporal model that integrates findings from several studies. Finally, we discuss the advantages and limitations of using binocular rivalry as a tool to investigate the neural basis of perceptual awareness.

  7. Correcting intermittent central suppression improves binocular marksmanship.

    Science.gov (United States)

    Hussey, Eric S

    2007-04-01

    Intermittent central suppression (ICS) is a defect in normal binocular (two-eyed) vision that causes confusion in visual detail. ICS is a repetitive intermittent loss of visual sensation in the central area of vision. As the central vision of either eye "turns on and off", aiming errors in sight can occur that must be corrected when both eyes are seeing again. Any aiming errors in sight might be expected to interfere with marksmanship during two-eyed seeing. We compared monocular (one-eyed, patched) and binocular (two-eyed) marksmanship with pistol shooting with an Army ROTC cadet before and after successful therapy for diagnosed ICS. Pretreatment, monocular marksmanship was significantly better than binocular marksmanship, suggesting defective binocularity reduced accuracy. After treatment for ICS, binocular and monocular marksmanship were essentially the same. Results confirmed predictions that with increased visual stability from correcting the suppression, binocular and monocular marksmanship accuracies should merge. PMID:17484315

  8. Scaling and Intermittency in Animal Behavior

    CERN Document Server

    Harnos, A; Lawrence, A B; Vattay, G

    1999-01-01

    Scale-invariant spatial or temporal patterns and Lévy flight motion have been observed in a large variety of biological systems. It has been argued that animals in general might perform Lévy flight motion with power law distribution of times between two changes of the direction of motion. Here we study the temporal behaviour of nesting gilts. The time spent by a gilt in a given form of activity has power law probability distribution without finite average. Further analysis reveals intermittent eruption of certain periodic behavioural sequences which are responsible for the scaling behaviour and indicates the existence of a critical state. We show that this behaviour is in close analogy with temporal sequences of velocity found in turbulent flows, where random and regular sequences alternate and form an intermittent sequence.

  9. Intermittence and roughening of periodic elastic media

    International Nuclear Information System (INIS)

    We analyze intermittence and roughening of an elastic interface or domain wall pinned in a periodic potential, in the presence of random-bond disorder in 1+1 and 2+1 dimensions. Though the ensemble average behavior is smooth, the typical behavior of a large sample is intermittent, and does not self-average to a smooth behavior. Instead, large fluctuations occur in the mean location of the interface and the onset of interface roughening is via an extensive fluctuation which leads to a jump in the roughness of order λ, the period of the potential. Analytical arguments based on extreme statistics are given for the number of the minima of the periodicity visited by the interface and for the roughening crossover, which is confirmed by extensive exact ground state calculations

  10. Radial evolution of solar wind intermittency in the inner heliosphere

    CERN Document Server

    Bruno, R; Sorriso-Valvo, L; Bavassano, B

    2003-01-01

    We analyzed intermittency in the solar wind, as observed on the ecliptic plane, looking at magnetic field and velocity fluctuations between 0.3 and 1 AU, for both fast and slow wind and for compressive and directional fluctuations. Our analysis focused on the property that probability distribution functions of a fluctuating field affected by intermittency become more and more peaked at smaller and smaller scales. Since the peakedness of a distribution is measured by its flatness factor we studied the behavior of this parameter for different scales to estimate the degree of intermittency of our time series. We confirmed that both magnetic field and velocity fluctuations are rather intermittent and that compressive magnetic fluctuations are generally more intermittent than the corresponding velocity fluctuations. In addition, we observed that compressive fluctuations are always more intermittent than directional fluctuations and that while slow wind intermittency does not depend on the radial distance from the ...

  11. Intermittent permeation of cylindrical nanopores by water

    OpenAIRE

    Allen, Rosalind; Melchionna, Simone; Hansen, Jean-Pierre

    2002-01-01

    Molecular Dynamics simulations of water molecules in nanometre sized cylindrical channels connecting two reservoirs show that the permeation of water is very sensitive to the channel radius and to electric polarization of the embedding material. At threshold, the permeation is {\\emph{intermittent}} on a nanosecond timescale, and strongly enhanced by the presence of an ion inside the channel, providing a possible mechanism for gating. Confined water remains surprisingly fluid and bulk-like. It...

  12. Intermittent chaotic chimeras for coupled rotators.

    Science.gov (United States)

    Olmi, Simona; Martens, Erik A; Thutupalli, Shashi; Torcini, Alessandro

    2015-09-01

    Two symmetrically coupled populations of N oscillators with inertia m display chaotic solutions with broken symmetry similar to experimental observations with mechanical pendulums. In particular, we report evidence of intermittent chaotic chimeras, where one population is synchronized and the other jumps erratically between laminar and turbulent phases. These states have finite lifetimes diverging as a power law with N and m. Lyapunov analyses reveal chaotic properties in quantitative agreement with theoretical predictions for globally coupled dissipative systems.

  13. Intermittently Flowing Rivers of Quantized Magnetic Flux

    OpenAIRE

    Nori, Franco

    1997-01-01

    Recent experiments and realistic flux-gradient-driven computer simulations provide evidence of plastic flow of flux lines in a superconductor. The striking videos of the onset of vortex motion vividly illustrate the existence of flowing "rivers" of quantized magnetic flux that intermittently form, freeze, and reappear at different locations in the sample. These rivers flow around "islands" (or domains) of flux lines which are temporarily trapped by the pinning sites. The shape and size of the...

  14. Challenging Oneself Intermittently to Improve Health

    OpenAIRE

    Mattson, Mark P.

    2014-01-01

    Humans and their predecessors evolved in environments where they were challenged intermittently with: 1) food scarcity; 2) the need for aerobic fitness to catch/kill prey and avoid or repel attackers; and 3) exposure to biological toxins present in foodstuffs. Accordingly, cells and organ systems acquired and retained molecular signaling and metabolic pathways through which the environmental challenges enhanced the functionality and resilience of the cells and organisms. Within the past 60 ye...

  15. Intermittent control of unstable multivariate systems.

    Science.gov (United States)

    Loram, I; Gawthrop, P; Gollee, H

    2015-08-01

    A sensorimotor architecture inspired from biological, vertebrate control should (i) explain the interface between high dimensional sensory analysis, low dimensional goals and high dimensional motor mechanisms and (ii) provide both stability and flexibility. Our interest concerns whether single-input-single-output intermittent control (SISO_IC) generalized to multivariable intermittent control (MIC) can meet these requirements.We base MIC on the continuous-time observer-predictorstate-feedback architecture. MIC uses event detection. A system matched hold (SMH), using the underlying continuoustime optimal control design, generates multivariate open-loop control signals between samples of the predicted state. Combined, this serial process provides a single-channel of control with optimised sensor fusion and motor synergies. Quadratic programming provides constrained, optimised equilibrium control design to handle unphysical configurations, redundancy and provides minimum, necessary reduction of open loop instability through optimised joint impedance. In this multivariate form, dimensionality is linked to goals rather than neuromuscular or sensory degrees of freedom. The biological and engineering rationale for intermittent rather than continuous multivariate control, is that the generalised hold sustains open loop predictive control while the open loop interval provides time within the feedback loop for online centralised, state dependent optimisation and selection. PMID:26736539

  16. Chronic Diarrhea

    Science.gov (United States)

    ... infections that cause chronic diarrhea be prevented? Chronic Diarrhea What is chronic diarrhea? Diarrhea that lasts for more than 2-4 ... represent a life-threatening illness. What causes chronic diarrhea? Chronic diarrhea has many different causes; these causes ...

  17. Resultados materno-fetales de la gestación tras cirugía bariátrica Maternal and fetal outcomes in pregnancy following bariatric surgery

    Directory of Open Access Journals (Sweden)

    I. González Navarro

    2011-04-01

    Full Text Available Introducción: La obesidad es la enfermedad metabòlica más frecuente en el mundo y conlleva múltiples co-morbilidades, siendo la cirugía bariátrica (CB una opción terapéutica cuando fallan las medidas clásicas. La mitad de los pacientes intervenidos son mujeres en edad fértil y está demostrado que la obesidad se asocia a peores resultados obstétricos y fetales. Dado que el estado nutricional se ve afectado por la CB y es un factor esencial para el adecuado desarrollo del embarazo, el objetivo de nuestro trabajo es valorar los efectos de la CB sobre la gestación en mujeres obesas intervenidas. Material y métodos: Seguimiento de 10 mujeres y 15 gestaciones tras CB durante el periodo 2003-2009. Se realizaron visitas trimestrales en consultas de Nutrición y Obstetricia, con evaluación clínica y de laboratorio en cada una. Resultados: Se evidenció deficiencia de hierro en el 80% de las gestaciones, de vitamina D en el 46,7%, de vitamina A en el 20%, de vitamina E en el 13,3% y de vitamina B12 en el 26,7%. No hubo complicaciones durante la gestación salvo un caso de hiperemesis gravidica. Hubo 9 partos de recién nacidos vivos sin malformaciones de los cuales 3 fueron recién nacidos pequeños para la edad gestacional (RNPEG y uno presentó neumonía por aspiración de meconio. Hubo 3 abortos y un parto prematuro con feto muerto. Conclusiones: En nuestro grupo de estudio hubo menos complicaciones durante la gestación comparado con lo descrito en obesas no operadas y similares a la población general.Background: Obesity is the most frecuent metabolic disease in the World, and is associated with several comorbidities. Bariatric procedures arise as a promising treatment when classical approach is ineffective. Half of the operated patients are reproductive-aged women and there is evidence that obesity is related to worse maternal and fetal outcomes. Because nutritional status is affected by bariatric surgery and is a vital component during pregnancy, the aim of our study is to asses the impact of bariatric surgery on pregnancy in these pacients. Material and methods: We studied 10 women and 15 pregnancies following bariatric surgery between 2003 and 2009. The visits took place every three months by an obstetrician and an endocrinologist with experience in nutrition, recording clinical features and lab work. Results: We found iron deficiency in 80% of the pregnancies, vitamin D in 46,7%, vitamin A in 20%, vitamin E in 13,3% and vitamin B12 in 26,7%. There were no complications during pregnancy, except one case of gravidic hiperemesis. There were nine deliveries without malformations, three of them were small for gestational age newborns and one suffered aspiration pneumonia. There were three stillbirths and one preterm delivery with fetal death. Conclusions: our results show fewer complications during pregnancy in these women than obese women and similar to general population.

  18. Steroids for Chronic Inflammatory Demyelinating Polyneuropathy

    OpenAIRE

    J Gordon Millichap

    2005-01-01

    The efficacy and safety of high-dose, intermittent IV methylprednisolone (IVMP) as initial and long-term maintenance therapy for chronic inflammatory demyelinating polyneuropathy (CIDP) were analyzed by a retrospective review of outcome data derived from patients’ medical records between 1992 and 2003 at Washington University School of Medicine, St Louis, MO.

  19. Steroids for Chronic Inflammatory Demyelinating Polyneuropathy

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2005-03-01

    Full Text Available The efficacy and safety of high-dose, intermittent IV methylprednisolone (IVMP as initial and long-term maintenance therapy for chronic inflammatory demyelinating polyneuropathy (CIDP were analyzed by a retrospective review of outcome data derived from patients’ medical records between 1992 and 2003 at Washington University School of Medicine, St Louis, MO.

  20. Gastrointestinal bleeding due to large bowel infiltration by chronic lymphocytic leukaemia.

    OpenAIRE

    Tucker, J.; Cachia, P. G.

    1986-01-01

    A 66 year old woman with a 9 year history of chronic lymphocytic leukaemia developed intermittent rectal bleeding for 9 months; sigmoidoscopic biopsy proved that this was due to large bowel infiltration by leukaemia. This is a very rare occurrence.

  1. Chronic Pseudomonas aeruginosa infection definition: EuroCareCF Working Group report

    DEFF Research Database (Denmark)

    Pressler, T; Bohmova, C; Conway, S;

    2011-01-01

    Chronic pulmonary infection with P. aeruginosa develops in most patients with cystic fibrosis (CF); by adulthood 80% of patients are infected and chronic P. aeruginosa infection is the primary cause of increased morbidity and mortality in CF. Chronic infection is preceded by an intermittent stage...

  2. Infiltration Effects on Residential Pollutant Concentrations for Continuous and Intermittent Mechanical Ventilation Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, Max; Logue, Jennifer; Singer, Brett

    2010-06-01

    The prevailing residential ventilation standard in North America, American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 62.2, specifies volumetric airflow requirements as a function of the overall size of the home and the number of bedrooms, assumes a fixed, minimal amount of infiltration, and requires mechanical ventilation to achieve the remainder. The standard allows for infiltration credits and intermittent ventilation patterns that can be shown to provide comparable performance. Whole-house ventilation methods have a substantial effect on time-varying indoor pollutant concentrations. If alternatives specified by Standard 62.2, such as intermittent ventilation, are used, short-term pollutant concentrations could exceed acute health standards even if chronic health standards are met.The authors present a methodology for comparing ASHRAE- and non-ASHRAE-specified ventilation scenarios on relative indoor pollutant concentrations. We use numerical modeling to compare the maximum time-averaged concentrations for acute exposure relevant (1-hour, 8-hour, 24-hour ) and chronic exposure relevant (1-year) time periods for four different ventilation scenarios in six climates with a range of normalized leakage values. The results suggest that long-term concentrations are the most important metric for assessing the effectiveness of whole-house ventilation systems in meeting exposure standards and that, if chronic health exposure standards are met, acute standards will also be met.

  3. UNSTEADY INTERMITTENT FLOW IN A ROTATING CURVED PIPE

    Institute of Scientific and Technical Information of China (English)

    YIN Jian-an; SHEN Xin-rong; CHEN Hua-jun; ZHANG Ben-zhao

    2004-01-01

    The effects of rotation and intermittent fre quency on the flow transition of secondary flow and, main flow were examined in detail. Certain hitherto unknown flow patterns were found. A numerical study was performed to study the characteristics of unsteady intermittent flow in a rotating curved pipe. Due to the rotation, both the Coriolis force and the centrifugal force could contribute to the unsteady intermittent flow and some complicated phenomena can be found. The results indicate that the unsteady intermittent flow are mainly characterized by five parameters: the Dean number Dn , the curvatureκ, the maximal force ratio F (of the Coriolis force to the centrifugal force in a cycle), the intermittent frequency parameter η(the ratio of a pulslating time to the cycle period), and the Womersley number α. Present works shows the natures of the unsteady intermittent flow in a rotating curved pipe.

  4. Acute intermittent porphyria in the puerperium

    Directory of Open Access Journals (Sweden)

    Sparić Radmila

    2010-01-01

    Full Text Available Introduction. Acute intermittent porphyria emerges as a result of partial defect of porphobilinogen deaminase and is manifested by repeated episodes of somatic, psychiatric and neurological disorders. The disease is conducted via the autosomaldominant gene of variable penetration, so most of the carriers never experience seizures. Timely making of diagnosis, screening of blood relatives of the patient and education of patients on avoidance of provoking factors are the key to adequate treatment. Case Outline. A 23-year-old patient having born the third child was hospitalized due to pains in the abdomen and convulsive seizures nine days after the vaginal delivery. At admittance, she suffered a generalized convulsive seizure of clonic-tonic type. The patient immediately underwent a complete clinical, laboratory, bacteriological and ultrasound examination. Bearing in mind the fact that the patient had several convulsive seizures even after the given neurological therapy, haem-arginate was introduced into therapy during four days. The administration of haem-arginate led to the normalization of blood pressure, pulse and bowel function. The administration of haem-arginate led to the normalization of blood pressure, pulse and bowel function. The patient was treated by a team of doctors, in the intensive care ward, with the use of medicaments, which are allowed in the case of acute porphyria. Sixteen days after the admittance, with clean neurological status and gynaecological and ultra-sound findings, she was released for ambulatory treatment. Conclusion. The presented case exhibits the gravity of making a diagnosis of acute intermittent porphyria in puerperium and the necessity of multi-disciplinary approach in treating this disease. Acute intermittent porphyria should be considered in cases of ambiguous abdominal pain, as well as in patients having abdominal pains followed by neuro-psychiatric disorders.

  5. [Acute intermittent porphyria and inappropriate ADH syndrome].

    Science.gov (United States)

    Tébar, M T; Aguilera, L

    2010-05-01

    A 44-year-old woman complained of abdominal pain of 4 days' duration accompanied by vomiting and painful urination. The admitting physician noted neurologic signs consistent with axonal polyneuropathy and hyponatremia. In the absence of other explanations for the syndrome, SIADH was diagnosed. Because of the nonspecific nature of the observations, the patient was assessed by various specialists and admitted to the anesthetic recovery unit due to worsening of neurologic signs and suspicion of acute intermittent porphyria. The diagnosis was confirmed by laboratory findings of elevated d-aminolevulinic acid and porphobilinogen levels and normal stool porphyrins. The patient improved with intravenous hematin infused over 4 days.

  6. Intermittency pattern of fluctuations in nuclear multifragmentation

    International Nuclear Information System (INIS)

    The method of scaled factorial moments is used to study fluctuations of the fragment size distribution in the percolation model and in nuclear multifragmentation following the breakup of the high energy nuclei in the nuclear emulsion. The percolation model accounts well for the fluctuations in the nuclear fragmentation process. An intermittent pattern of fluctuations is found in the data suggesting a self-similarity in the fragment size distribution and a random character for the scaling law. However, no evidence of the critical behaviour in nuclear multifragmentation is found. (orig.)

  7. Transition to turbulence, intermittence, and vortex fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Bershadskii, A.G.

    1985-09-01

    A model is developed which describes the fluctuation coalescence of vortices at moderately high Reynolds numbers. The model is found to be in good agreement with experimental data on (1) flow intermittence in a boundary layer, a round jet, and a plane wake; (2) the effect of a magnetic field on the formation of a turbulent energy spectrum behind a grid and on turbulent fluctuations and friction in ducts; (3) formation of a turbulent energy spectrum in a boundary layer and in ducts. 12 references.

  8. The Yo-Yo intermittent recovery test

    DEFF Research Database (Denmark)

    Bangsbo, Jens; Iaia, F. Marcello; Krustrup, Peter

    2008-01-01

    (Yo-Yo IR2) determines an individual's ability to recover from repeated exercise with a high contribution from the anaerobic system. Evaluations of elite athletes in various sports involving intermittent exercise showed that the higher the level of competition the better an athlete performs in the Yo......-Yo IR tests. Performance in the Yo-Yo IR tests for young athletes increases with rising age. The Yo-Yo IR tests have shown to be a more sensitive measure of changes in performance than maximum oxygen uptake. The Yo-Yo IR tests provide a simple and valid way to obtain important information...

  9. Enhanced sarcoplasmic reticulum Ca(2+) release following intermittent sprint training

    DEFF Research Database (Denmark)

    Ørtenblad, Niels; Lunde, Per; Levin, Kasper;

    2000-01-01

    To evaluate the effect of intermittent sprint training on sarcoplasmic reticulum (SR) function, nine young men performed a 5 wk high-intensity intermittent bicycle training, and six served as controls. SR function was evaluated from resting vastus lateralis muscle biopsies, before and after...... the training period. Intermittent sprint performance (ten 8-s all-out periods alternating with 32-s recovery) was enhanced 12% (P sprint training induced a significantly higher (P

  10. Regionalization of patterns of flow intermittence from gauging station records

    OpenAIRE

    Snelder, T.H.; Datry, T.; Lamouroux, N.; Larned, S. T.; E. Sauquet; Pella, H.; C. Catalogne

    2013-01-01

    Understanding large-scale patterns in flow intermittence is important for effective water resource management. We used daily flow records from 628 gauging stations on rivers with minimally modified flows distributed throughout France to predict regional patterns of flow intermittence. For each station we calculated two annual times-series describing flow intermittence; the frequency of zero-flow periods (consecutive days of zero-flow) in each year of record (FREQ; yr−1)...

  11. Beneficial effects of intermittent hypobaric hypoxia on the body

    Institute of Scientific and Technical Information of China (English)

    Yi ZHANG; Zhao-nian ZHOU

    2012-01-01

    Myocardial ischemia and reperfusion (I/R) is a common problem in clinic and there is no satisfactory method for prevention or treatment of I/R injury so far.Chronic intermittent hypobaric hypoxia (CIHH),similar to the concept of ischemia preconditioning(IPC)or altitude hypoxia adaptation (AHA),has been recognized to confer a protective effect on heart against I/R injury with a longer protective effect than IPC and a less adverse effect than AHA.It has been proved that CIHH increases myocardial tolerance to ischemia or hypoxia,reserving cardiac function and preventing arrhythmia during I/R.Multiple mechanisms or pathway underlying the cardiac protection of ClHH have been proposed,such as induction of heatshock protein,enhancement of myocardial antioxidation capacity,increase of coronary flow and myocardial capillary angiogenesis,activation of adenosine triphosphate (ATP)-sensitive potassium channels,inhibition of mitochondrial permeability transition pores,and activation of protein kinase C (PKC) and induced nitric oxide synthase (iNOS).In addition,CIHH has been found having many beneficial effects on the body,such as promotion of health,increase of oxygen utilization,and prevention or treatment for some diseases.The beneficial effects of ClHH and potential mechanisms are reviewed mainly based on the researches performed by our group.

  12. Intermittent lag synchronization in a driven system of coupled oscillators

    Indian Academy of Sciences (India)

    Alexander N Pisarchik; Rider Jaimes-Reátegui

    2005-04-01

    We study intermittent lag synchronization in a system of two identical mutually coupled Duffing oscillators with parametric modulation in one of them. This phenomenon in a periodically forced system can be seen as intermittent jump from phase to lag synchronization, during which the chaotic trajectory visits a periodic orbit closely. We demonstrate different types of intermittent lag synchronizations, that occur in the vicinity of saddle-node bifurcations where the system changes its dynamical state, and characterize the simplest case of period-one intermittent lag synchronization.

  13. Projective synchronization of a hyperchaotic system via periodically intermittent control

    Institute of Scientific and Technical Information of China (English)

    Huang Jun-Jian; Li Chuan-Dong; Zhang Wei; Wei Peng-Cheng

    2012-01-01

    We further study the projective synchronization of a new hyperchaotic system.Different from the most existing methods,intermittent control is applied to chaotic synchronization in the present paper.We formulate the intermittent control system that governs the dynamics of the projective synchronization error,then derive the sufficient conditions for the exponential stability of intermittent control system by using the Lyapunov stability theory,and finally establish the periodically intermittent controller according to the stability criterion by which the projective synchronization is expected to be achieved.The analytical results are also demonstrated by several numerical simulations.

  14. Strain intermittency in shape-memory alloys

    Science.gov (United States)

    Balandraud, Xavier; Barrera, Noemi; Biscari, Paolo; Grédiac, Michel; Zanzotto, Giovanni

    2015-05-01

    We study experimentally the intermittent progress of the mechanically induced martensitic transformation in a Cu-Al-Be single crystal through a full-field measurement technique: the grid method. We utilize an in-house, specially designed gravity-based device, wherein a system controlled by water pumps applies a perfectly monotonic uniaxial load through very small force increments. The sample exhibits hysteretic superelastic behavior during the forward and reverse cubic-monoclinic transformation, produced by the evolution of the strain field of the phase microstructures. The in-plane linear strain components are measured on the sample surface during the loading cycle, and we characterize the strain intermittency in a number of ways, showing the emergence of power-law behavior for the strain avalanching over almost six decades of magnitude. We also describe the nonstationarity and the asymmetry observed in the forward versus reverse transformation. The present experimental approach, which allows for the monitoring of the reversible martensitic transformation both locally and globally in the crystal, proves useful and enhances our capabilities in the analysis and possible control of transition-related phenomena in shape-memory alloys.

  15. Intermittent heat instabilities in an air plume

    Science.gov (United States)

    Le Mouël, Jean-Louis; Kossobokov, Vladimir G.; Perrier, Frederic; Morat, Pierre

    2016-08-01

    We report the results of heating experiments carried out in an abandoned limestone quarry close to Paris, in an isolated room of a volume of about 400 m3. A heat source made of a metallic resistor of power 100 W was installed on the floor of the room, at distance from the walls. High-quality temperature sensors, with a response time of 20 s, were fixed on a 2 m long bar. In a series of 24 h heating experiments the bar had been set up horizontally at different heights or vertically along the axis of the plume to record changes in temperature distribution with a sampling time varying from 20 to 120 s. When taken in averages over 24 h, the temperatures present the classical shape of steady-state plumes, as described by classical models. On the contrary, the temperature time series show a rich dynamic plume flow with intermittent trains of oscillations, spatially coherent, of large amplitude and a period around 400 s, separated by intervals of relative quiescence whose duration can reach several hours. To our knowledge, no specific theory is available to explain this behavior, which appears to be a chaotic interaction between a turbulent plume and a stratified environment. The observed behavior, with first-order factorization of a smooth spatial function with a global temporal intermittent function, could be a universal feature of some turbulent plumes in geophysical environments.

  16. Influence of Dehydration on Intermittent Sprint Performance.

    Science.gov (United States)

    Davis, Jon-Kyle; Laurent, C Matt; Allen, Kimberly E; Green, J Matt; Stolworthy, Nicola I; Welch, Taylor R; Nevett, Michael E

    2015-09-01

    This study examined the effects of dehydration on intermittent sprint performance and perceptual responses. Eight male collegiate baseball players completed intermittent sprints either dehydrated (DEHY) by 3% body mass or euhydrated (EU). Body mass was reduced through exercise in the heat with controlled fluid restriction occurring 1 day before the trial. Participants completed twenty-four 30-m sprints divided into 3 bouts of 8 sprints with 45 seconds of rest between each sprint and 3 minutes between each bout. Perceived recovery status (PRS) scale was recorded before the start of each trial. Heart rate (HR), ratings of perceived exertion (RPE) (0-10 OMNI scale), and perceived readiness (PR) scale were recorded after every sprint, and session RPE (SRPE) was recorded 20 minutes after completing the entire session. A 2 (condition) × 3 (bout of sprints) repeated-measures ANOVA revealed a significant main effect of condition on mean sprint time (p = 0.03), HR (p Dehydration impaired sprint performance, negatively altered perception of recovery status before exercise, and increased RPE and HR response.

  17. Shearing of Materials with Intermittent Joints

    Science.gov (United States)

    Gerolymatou, Eleni; Triantafyllidis, Theodoros

    2016-07-01

    The strength of fractures is much lower as a rule than that of intact rock. As a result they play a controlling part in the mechanical behaviour in general and the failure in particular of rock mass. Though a large volume of experimental data is available on the shear resistance of joints, as well as on the propagation of single cracks, the same is not true for the mechanical behaviour of intermittent joints. The experimental data available in this case are limited and the strength of rock mass with intermittent joints is usually modelled using averaged values of cohesion or assuming the fractures to be continuous. In the present work, the results of simple shear tests on a series of gypsum specimens with pre-existing cracks are presented. Twelve different crack orientations and two normal stresses were tested. The hypothesis of averaged cohesion and the theory of fracture mechanics are used to reproduce the results. It is found that fracture mechanics provides a more suitable model for the experimental results, especially when crack interaction is taken into account.

  18. Challenging oneself intermittently to improve health.

    Science.gov (United States)

    Mattson, Mark P

    2014-12-01

    Humans and their predecessors evolved in environments where they were challenged intermittently with: 1) food scarcity; 2) the need for aerobic fitness to catch/kill prey and avoid or repel attackers; and 3) exposure to biological toxins present in foodstuffs. Accordingly, cells and organ systems acquired and retained molecular signaling and metabolic pathways through which the environmental challenges enhanced the functionality and resilience of the cells and organisms. Within the past 60 years there has been a precipitous diminution of such challenges in modern societies because of the development of technologies that provide a continuous supply of energy-dense processed foods and that largely eliminate the need for physical exertion. As a consequence of the modern 'couch potato' lifestyle, signaling pathways that mediate beneficial effects of environmental challenges on health and disease resistance are disengaged, thereby rendering people vulnerable to obesity, diabetes, cardiovascular disease, cancers and neurodegenerative disorders. Reversal of the epidemic of diseases caused by unchallenging lifestyles will require a society-wide effort to re-introduce intermittent fasting, exercise and consumption of plants containing hormetic phytochemicals into daily and weekly routines. PMID:25552960

  19. Regionalization of patterns of flow intermittence from gauging station records

    Science.gov (United States)

    Snelder, T. H.; Datry, T.; Lamouroux, N.; Larned, S. T.; Sauquet, E.; Pella, H.; Catalogne, C.

    2013-07-01

    Understanding large-scale patterns in flow intermittence is important for effective river management. The duration and frequency of zero-flow periods are associated with the ecological characteristics of rivers and have important implications for water resources management. We used daily flow records from 628 gauging stations on rivers with minimally modified flows distributed throughout France to predict regional patterns of flow intermittence. For each station we calculated two annual times series describing flow intermittence; the frequency of zero-flow periods (consecutive days of zero flow) in each year of record (FREQ; yr-1), and the total number of zero-flow days in each year of record (DUR; days). These time series were used to calculate two indices for each station, the mean annual frequency of zero-flow periods (mFREQ; yr-1), and the mean duration of zero-flow periods (mDUR; days). Approximately 20% of stations had recorded at least one zero-flow period in their record. Dissimilarities between pairs of gauges calculated from the annual times series (FREQ and DUR) and geographic distances were weakly correlated, indicating that there was little spatial synchronization of zero flow. A flow-regime classification for the gauging stations discriminated intermittent and perennial stations, and an intermittence classification grouped intermittent stations into three classes based on the values of mFREQ and mDUR. We used random forest (RF) models to relate the flow-regime and intermittence classifications to several environmental characteristics of the gauging station catchments. The RF model of the flow-regime classification had a cross-validated Cohen's kappa of 0.47, indicating fair performance and the intermittence classification had poor performance (cross-validated Cohen's kappa of 0.35). Both classification models identified significant environment-intermittence associations, in particular with regional-scale climate patterns and also catchment area, shape

  20. Regionalization of patterns of flow intermittence from gauging station records

    Directory of Open Access Journals (Sweden)

    T. H. Snelder

    2013-01-01

    Full Text Available Understanding large-scale patterns in flow intermittence is important for effective water resource management. We used daily flow records from 628 gauging stations on rivers with minimally modified flows distributed throughout France to predict regional patterns of flow intermittence. For each station we calculated two annual times-series describing flow intermittence; the frequency of zero-flow periods (consecutive days of zero-flow in each year of record (FREQ; yr−1, and the total number of zero-flow days in each year of record (DUR; days. These time series were used to calculate two indices for each station, the mean annual frequency of zero-flow periods (mFREQ; yr−1, and the mean duration of zero-flow periods (mDUR; days. Approximately 20% of stations had recorded at least one zero-flow period. Dissimilarities between pairs of gauges calculated from the annual times-series (FREQ and DUR and geographic distances were weakly correlated, indicating that there was little spatial synchronization of zero-flow. A flow-regime classification for the gauging stations discriminated intermittent and perennial stations, and an intermittence classification grouped intermittent stations into three classes based on the values of mFREQ and mDUR. We used Random Forest (RF models to relate the flow-regime and intermittence classifications to several environmental characteristics of the gauging station catchments. The RF model of the flow-regime classification had a cross-validated Cohen's kappa of 0.47, indicating fair performance and the intermittence classification had poor performance (cross-validated Cohen's kappa of 0.35. Both classification models identified significant environment-intermittence associations, in particular with regional-scale climate patterns and also catchment area, shape and slope. However, we suggest that the fair-to-poor performance of the classification models is because intermittence is also controlled by

  1. Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance

    Directory of Open Access Journals (Sweden)

    Lindsay B. Baker

    2015-07-01

    Full Text Available Intermittent sports (e.g., team sports are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1–2 h. Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1 potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2 the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3 what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports. Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30–60 g/h in the form of a 6%–7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before

  2. 21 CFR 868.5955 - Intermittent mandatory ventilation attachment.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intermittent mandatory ventilation attachment. 868.5955 Section 868.5955 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... mandatory ventilation attachment. (a) Identification. An intermittent mandatory ventilation (IMV)...

  3. Intermittent Versus Continuous Phototherapy for Reducing Neonatal Hyperbilirubinemia

    OpenAIRE

    Nikoo Niknafs; Bahare Bahman-Bijari; Mohammad Hossein Torabinejad; Abdol-Ali Mortazavi; Pedram Niknafs

    2008-01-01

    Objective: Clinical studies comparing intermittent versus continuous phototherapy for reducing neonatal hyperbilirubinemia have produced conflicting results. This study was conducted to compare the efficacy of intermittent with continuous phototherapy. Methods: This study was performed on 114 neonates with indirect hyperbilirubinemia. Inclusion criteria were body weight above 2000 grams, absence of other concomitant diseases, and hyperbilirubinemia neither requiring intensive phototherapy nor...

  4. Bound by Children: Intermittent Cohabitation and Living Together Apart

    Science.gov (United States)

    Cross-Barnet, Caitlin; Cherlin, Andrew; Burton, Linda

    2011-01-01

    In this article, we examine variations in low-income mothers' patterns of intermittent cohabitation and the voluntary and involuntary nature of these unions. Intermittent cohabitation involves couples living together and separating in repeating cycles. Using Three-City Study ethnographic data, we identified 45 low-income mothers involved in these…

  5. Intermittent versus Continuous Physiotherapy in Children with Cerebral Palsy

    Science.gov (United States)

    Christiansen, Annette Sandahl; Lange, Christa

    2008-01-01

    The aim of this study was to compare the effect of the delivery of the same amount of intermittent versus continuous physiotherapy given to children with cerebral palsy (CP). This was organized either in an intermittent regime four times a week for 4 weeks alternating with a 6-week treatment pause, or a continuous once or twice a week regime, both…

  6. Intermittent drying of beans in a spouted bed

    Directory of Open Access Journals (Sweden)

    C. A. Oliveira

    2007-12-01

    Full Text Available Carioca beans are a highly nutritious grain, in terms of the amount of protein, iron and potassium as well as carbohydrates and fiber and as a source of vitamins. The moisture content of recently picked beans is too high for good preservation and storage, resulting in the need for drying before packaging. In this work, the drying of Carioca beans in a laboratory scale spouted bed under intermittent conditions of the drying air was experimentally analyzed. Experiments carried out consisted of two types of intermittent regime: intermittence in the spout regime, referred to as spouted/fixed bed and intermittence of the air supply to the bed, called spouted bed/rest. The results were compared to those for bean drying in a spouted bed dryer without intermittence.

  7. Voltage Stability Evaluation Incorporating Wind Power Intermittency

    Institute of Scientific and Technical Information of China (English)

    Libao SHI; Yang ZHAO; Yixin NI; Liangzhong YAO; Masoud BAZARGAN

    2013-01-01

    A simulation framework is proposed to evaluate the voltage stability of power systems incorporating wind power intermittency.Firstly,the power output modelings of three types of wind turbines are discussed.Secondly,the Jensen model is employed to simulate the wind farm with the wake effect.The Monte Carlo based technique is used to conduct the voltage stability evaluation incorporating the randomness of the wind speed based on the Weibull probability distribution.Thirdly,the relative sensitivity index (RSI) is calculated to identify weak buses during analysis.Finally,case studies with different simulation scenarios are carried out.Some statistical results involving weakness probability,expected value and variance of RSI as well as preliminary conclusions are drawn based on numerical simulation results.

  8. Towards an intermittency-friendly energy system

    DEFF Research Database (Denmark)

    Blarke, Morten

    2012-01-01

    still has to offer. The solution is for distributed operators to adapt their technology and operational strategies to achieve a better co-existence between cogeneration and wind power. Four options for doing so are analysed including a new concept that integrates a high pressure compression heat pump...... are capitulating as wind power penetration levels are moving above 25%; some operators are retiring cogeneration units entirely, while other operators are making way for heat-only boilers. This development is jeopardizing the system-wide energy, economic, and environmental benefits that distributed cogeneration...... using low-temperature heat recovered from flue gasses in combination with an intermediate cold storage, which enables the independent operation of heat pump and cogenerator. It is found that an electric boiler provides consistent improvements in the intermittency-friendliness of distributed cogeneration...

  9. Intermittency of Energy Dissipation in Alfvenic Turbulence

    CERN Document Server

    Zhdankin, Vladimir; Chen, Christopher H K

    2015-01-01

    We investigate the intermittency of energy dissipation in Alfvenic turbulence by considering the statistics of the coarse-grained energy dissipation rate, using direct measurements from numerical simulations of magnetohydrodynamic turbulence and surrogate measurements from the solar wind. We compare the results to the predictions of the log-normal and log-Poisson random cascade models. We find that, to a very good approximation, the log-normal model describes the probability density function for the energy dissipation over a broad range of scales, but does not accurately describe the scaling exponents of the moments. The log-Poisson model better describes the scaling exponents of the moments, while the comparison with the probability density function is not straightforward.

  10. Muscle coordination changes during intermittent cycling sprints.

    Science.gov (United States)

    Billaut, François; Basset, Fabien A; Falgairette, Guy

    2005-06-01

    Maximal muscle power is reported to decrease during explosive cyclical exercises owing to metabolic disturbances, muscle damage, and adjustments in the efferent neural command. The aim of the present study was to analyze the influence of inter-muscle coordination in fatigue occurrence during 10 intermittent 6-s cycling sprints, with 30-s recovery through electromyographic activity (EMG). Results showed a decrease in peak power output with sprint repetitions (sprint 1 versus sprint 10: -11%, Pversus sprint 10: -90.2 ms, Pcycling sprints of short duration, decreased possibly due to the inability of muscles to maintain maximal force. This reduction in maximal power output occurred in parallel to changes in the muscle coordination pattern after fatigue. PMID:15862899

  11. Scintillation-Induced Intermittency in SETI

    CERN Document Server

    Cordes, J M; Sagan, Carl Edward; Cordes, James M.; Sagan, Carl

    1997-01-01

    We consider interstellar scintillations as a cause of intermittency in radio signals from extraterrestrial intelligence (ETI). We demonstrate that scintillations are very likely to allow initial detections of narrowband signals from distant sources (> 100 pc), while making redetections improbable. We consider three models in order to assess the non-repeating, narrowband events found in recent SETI and to analyze large surveys in general: (I) Radiometer noise; (II) A population of constant Galactic sources undergoing interstellar scintillation,; and (III) Real, transient signals (or hardware errors) of either terrestrial or ET origin. We apply likelihood and Bayesian tests of the models to The Planetary Society/Harvard META data. We find that Models II and III are both highly preferred to Model I, but that Models II and III are about equally likely. Ruling out Model II in favor of Model III requires many more reobservations than were conducted in META *or* the reobservation threshold must be much lower than wa...

  12. Finite dissipation and intermittency in magnetohydrodynamics

    CERN Document Server

    Mininni, P D

    2009-01-01

    We present an analysis of data stemming from numerical simulations of decaying magnetohydrodynamic (MHD) turbulence up to grid resolution of 1536^3 points and up to Taylor Reynolds number of 1200. The initial conditions are such that the initial velocity and magnetic fields are helical and in equipartition, while their correlation is negligible. Analyzing the data at the peak of dissipation, we show that the dissipation in MHD seems to asymptote to a constant as the Reynolds number increases, thereby strengthening the possibility of fast reconnection events in the solar environment for very large Reynolds numbers. Furthermore, intermittency of MHD flows, as determined by the spectrum of anomalous exponents of structure functions of the velocity and the magnetic field, is stronger than for fluids, confirming earlier results; however, we also find that there is a measurable difference between the exponents of the velocity and those of the magnetic field, as observed recently in the solar wind. Finally, we discu...

  13. Intermittent drinking, oxytocin and human health.

    Science.gov (United States)

    Pruimboom, L; Reheis, D

    2016-07-01

    Looking at a waterhole, it is surprising that so many animals share the same space without visible signs of anxiety or aggression. Although waterholes are the preferred feeding locations of large carnivores, waterholes are shared by all type of herbivores of all sizes and shapes, including elephants. Recent research shows that the homeostatic disturbances leading to the "thirst feeling" not only activate specific substances regulating water and mineral household, but also the "trust and love" hormone oxytocin, while decreasing the production of the typical stress hormone cortisol. People using drugs, seem to be in search for oxytocin, as evidenced in studies with individuals on drugs such as ecstasy and gamma-hydroxybyturate. Hot environment, drought and increased sweating also activate specific oxytocin-producing parts of the hypothalamus, just as breastfeeding does in mother and infant. Water homeostasis is the only allostatic system activating trust neuro-anatomy and we suggest that this is due to the fact that all animals depend on water, whereas food type is species specific. Our hypothesis; regulating drinking behaviour through intermittent bulk drinking could increase oxytocin signalling, recover human trust and increase health by down-regulation of stress axis activity and inflammatory activity of the immune system. Intermittent bulk drinking should be defined as water (including tea and coffee) drinking up to a feeling of satiety and regulated by a mild feeling of thirst. This would mean that people would not drink less quantity but less frequently and that's how all animals, but also human newborns behave. It is the latter group, which is probably the only group of humans with a normal fluid homeostasis. PMID:27241263

  14. Mixing and diffusion in intermittent overturning turbulence

    Science.gov (United States)

    Redondo, Jose M.; Mahjoub, Otman B.; Gonzalez-Nieto, Pilar L.; Lawry, Andrew

    2014-05-01

    The improvements in experimental methods and high resolution image analysis are nowadays able to detect subtle changes in the structure of the turbulence over a wide range of temporal and spatial scales [1], we compare the scaling shown by different mixing fronts driven by buoyancy that form a Rayleigh-Taylor mixing front. We use PIV and density front tracking in several experimental configurations akin to geophysical overturning [2-7]. We parametrize the role of unstable stratification by means of the Atwood number and compare both the scaling and the multifractal and the maximum local fractal structure functions of the different markers used to visualize the front. Both reactive and passive scalar tracers are used to investigate the mixing structure and the intermittency of the flow. Different initial conditions are compared and the mixing efficiency of the overal turbulent process evaluated [6-7]. An interesting approach, relating the Multi-Fractal dimension spectra, the intermittency and the spectral exponent is to find relationships that may be used to parameterise the sub-grid turbulence in terms of generalized diffusivities [4 ] that take into account the topology and the self-similarity of the Mixing RT and RM flows. As an example, a relationship between the diffusivity, the exponent β, the intermittency μ, and D(i), may be found for the volume fraction or the concentration, at the same time other locally measured parameters such as the enstrophy or the gradient alignment as well as their multi-fractal structures may turn out to be physically relevant indicators of the local turbulence and the mixing. Several methods of deriving local eddy diffusivity and local entrainment should give more realistic estimates of the spatial/temporal non-homogeneities (and intermittencies in the Kolmogorov 62 sense obtained as spatial correlations of the turbulent dissipation, or from structure functions) and these values may be used to parameterise turbulence at a variety

  15. Identification of intermittent control in man and machine.

    Science.gov (United States)

    Loram, Ian D; van de Kamp, Cornelis; Gollee, Henrik; Gawthrop, Peter J

    2012-09-01

    Regulation by negative feedback is fundamental to engineering and biological processes. Biological regulation is usually explained using continuous feedback models from both classical and modern control theory. An alternative control paradigm, intermittent control, has also been suggested as a model for biological control systems, particularly those involving the central nervous system. However, at present, there is no identification method explicitly formulated to distinguish intermittent from continuous control; here, we present such a method. The identification experiment uses a special paired-step set-point sequence. The corresponding data analysis use a conventional ARMA model to relate a theoretically derived equivalent set-point to control signal; the novelty lies in sequentially and iteratively adjusting the timing of the steps of this equivalent set-point to optimize the linear time-invariant fit. The method was verified using realistic simulation data and was found to robustly distinguish not only between continuous and intermittent control but also between event-driven intermittent and clock-driven intermittent control. When applied to human pursuit tracking, event-driven intermittent control was identified, with an intermittent interval of 260-310 ms (n = 6, p < 0.05). This new identification method is applicable for machine and biological applications. PMID:22491973

  16. Valvoplastia aórtica por cateter-balão em emergência materno-fetal na adolescência Valvuloplastia aórtica por catéter con balón en emergencia materno-fetal en la adolescencia Aortic valvuloplasty with balloon catheter in maternal-fetal emergency in adolescence

    Directory of Open Access Journals (Sweden)

    Walkiria Samuel Avila

    2009-12-01

    Full Text Available O aumento do débito cardíaco durante a gravidez é causa de insuficiência cardíaca em portadoras de estenose valvar aórtica grave. A valvoplastia aórtica percutânea tem sido associada a graves complicações e reestenose valvar em curto prazo. O presente caso mostrou que a valvoplastia aórtica percutânea permitiu o alcance do parto com sobrevida da mãe e do feto, e que a interrupção do tratamento no pós-parto resultou em morte materna no puerpério tardio.El aumento del gasto cardiaco durante el embarazo es la causa de insuficiencia cardiaca en portadoras de estenosis valvular aórtica severa. Se viene asociando la valvuloplastia aórtica percutánea a severas complicaciones y reestenosis valvular en corto plazo. El presente caso reveló que la valvuloplastia aórtica percutánea permitió el alcance del parto con sobrevida de la madre y del feto, y que la interrupción del tratamiento en el postparto resultó en muerte materna en el puerperio tardío.The increase of cardiac output during pregnancy is the cause of heart failure in women with severe aortic valvular stenosis. Percutaneous aortic valvuloplasty has been associated with severe complications and short-term valvar restenosis. This case showed that percutaneous aortic valvuloplasty allowed both mother and fetus to survive after childbirth, and that postpartum treatment interruption resulted in maternal death in late postpartum care.

  17. Intermittent Renewable Management Pilot Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Kiliccote, Sila [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Homan, Gregory [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Anderson, Robert [Olivine, Inc., San Ramon, CA (United States); Hernandez, John [Pacific Gas & Electric Company, San Francisco, CA (United States)

    2015-04-01

    The Intermittent Renewable Management Pilot - Phase 2 (IRM2) was designed to study the feasibility of demand-side resources to participate into the California Independent System Operator (CAISO) wholesale market as proxy demand resources (PDR). The pilot study focused on understanding the issues related with direct participation of third-parties and customers including customer acceptance; market transformation challenges (wholesale market, technology); technical and operational feasibility; and value to the rate payers, DR resource owners and the utility on providing an enabling mechanism for DR resources into the wholesale markets. The customer had the option of committing to either three contiguous hour blocks for 24 days or six contiguous hours for 12 days a month with day-ahead notification that aligned with the CAISO integrated forward market. As a result of their being available, the customer was paid $10/ kilowatt (kW)-month for capacity in addition to CAISO energy settlements. The participants were limited to no more than a 2 megawatt (MW) capacity with a six-month commitment. Four participants successfully engaged in the pilot. In this report, we provide the description of the pilot, participant performance results, costs and value to participants as well as outline some of the issues encountered through the pilot. Results show that participants chose to participate with storage and the value of CAISO settlements were significantly lower than the capacity payments provided by the utility as incentive payments. In addition, this pilot revealed issues both on the participant side and system operations side. These issues are summarized in the report.The Intermittent Renewable Management Pilot - Phase 2 (IRM2) was designed to study the feasibility of demand-side resources to participate into the California Independent System Operator (CAISO) wholesale market as proxy demand resources (PDR). The pilot study focused on understanding the issues related with

  18. Evaluation of continuous and intermittent myocardial topical negative pressure

    DEFF Research Database (Denmark)

    Lindstedt, Sandra; Malmsjö, Malin; Gesslein, Bodil;

    2008-01-01

    Topical negative pressure, commonly used in wound therapy, has been shown to increase blood flow and stimulate angiogenesis in subcutaneous tissue and skeletal muscle. In wound therapy, intermittent negative pressure is often preferred to continuous negative pressure as tissue exposed...... to intermittent therapy shows twice as much granulation tissue formation than that exposed to continuous pressure after 2 weeks of therapy. The present study was designed to elucidate the differences in microvascular blood flow in the left anterior descending artery area between continuous and intermittent...

  19. Photoluminescence intermittency of semiconductor quantum dots in dielectric environments

    Energy Technology Data Exchange (ETDEWEB)

    Isaac, A.

    2006-08-11

    The experimental studies presented in this thesis deal with the photoluminescence intermittency of semiconductor quantum dots in different dielectric environments. Detailed analysis of intermittency statistics from single capped CdSe/ZnS, uncapped CdSe and water dispersed CdSe/ZnS QDs in different matrices provide experimental evidence for the model of photoionization with a charge ejected into the surrounding matrix as the source of PL intermittency phenomenon. We propose a self-trapping model to explain the increase of dark state lifetimes with the dielectric constant of the matrix. (orig.)

  20. Sex differences associated with intermittent swim stress.

    Science.gov (United States)

    Warner, Timothy A; Libman, Matthew K; Wooten, Katherine L; Drugan, Robert C

    2013-11-01

    Various animal models of depression have been used to seek a greater understanding of stress-related disorders. However, there is still a great need for novel research in this area, as many individuals suffering from depression are resistant to current treatment methods. Women have a higher rate of depression, highlighting the need to investigate mechanisms of sex differences. Therefore, we employed a new animal model to assess symptoms of depression, known as intermittent swim stress (ISS). In this model, the animal experiences 100 trials of cold water swim stress. ISS has already been shown to cause signs of behavioral depression in males, but has yet to be assessed in females. Following ISS exposure, we looked at sex differences in the Morris water maze and forced swim test. The results indicated a spatial learning effect only in the hidden platform task between male and female controls, and stressed and control males. A consistent spatial memory effect was only seen for males exposed to ISS. In the forced swim test, both sexes exposed to ISS exhibited greater immobility, and the same males and females also showed attenuated climbing and swimming, respectively. The sex differences could be due to different neural substrates for males and females. The goal of this study was to provide the first behavioral examination of sex differences following ISS exposure, so the stage of estrous cycle was not assessed for the females. This is a necessary future direction for subsequent experiments. The current article highlights the importance of sex differences in response to stress.

  1. Cutaneous sporotrichosis. Intermittent treatment (pulses) with itraconazole.

    Science.gov (United States)

    Bonifaz, Alexandro; Fierro, Leonel; Saúl, Amado; Ponce, Rosa María

    2008-01-01

    Sporotrichosis is a subcutaneous and exceptionally deep mycosis caused by a dimorphic fungus, Sporothrix schenckii. Itraconazole is a triazole derivative leading to good results in the treatment of sporotrichosis. Patients with cutaneous sporotrichosis proven with mycological tests (direct examination and culture) were enrolled. All patients underwent laboratory tests (at baseline and on a monthly basis) and received oral itraconazole 400 mg/day for one week with a 3-week break (pulses); thereafter the drug was administered as pulses until clinical and mycological cure was achieved. Five patients with sporotrichosis were enrolled, 4 with cutaneous lymphangitic form and one with fixed cutaneous form. Clinical and mycological cure was achieved in 4/5 cases (80%), with a mean number of pulses of 3.5. No patient had side effects and no laboratory test abnormalities occurred. Intermittent or pulsed itraconazole was effective in treating cutaneous sporotrichosis. It may be considered as a new treatment choice that entails an important reduction in total medication use.

  2. Finite dissipation and intermittency in magnetohydrodynamics.

    Science.gov (United States)

    Mininni, P D; Pouquet, A

    2009-08-01

    We present an analysis of data stemming from numerical simulations of decaying magnetohydrodynamic (MHD) turbulence up to grid resolution of 1536(3) points and up to Taylor Reynolds number of approximately 1200 . The initial conditions are such that the initial velocity and magnetic fields are helical and in equipartition, while their correlation is negligible. Analyzing the data at the peak of dissipation, we show that the dissipation in MHD seems to asymptote to a constant as the Reynolds number increases, thereby strengthening the possibility of fast reconnection events in the solar environment for very large Reynolds numbers. Furthermore, intermittency of MHD flows, as determined by the spectrum of anomalous exponents of structure functions of the velocity and the magnetic field, is stronger than that of fluids, confirming earlier results; however, we also find that there is a measurable difference between the exponents of the velocity and those of the magnetic field, reminiscent of recent solar wind observations. Finally, we discuss the spectral scaling laws that arise in this flow. PMID:19792189

  3. Long-range forecasting of intermittent streamflow

    Directory of Open Access Journals (Sweden)

    F. F. van Ogtrop

    2011-01-01

    Full Text Available Long-range forecasting of intermittent streamflow in semi-arid Australia poses a number of major challenges. One of the challenges relates to modelling zero, skewed, non-stationary, and non-linear data. To address this, a probabilistic statistical model to forecast streamflow 12 months ahead is applied to five semi-arid catchments in South Western Queensland. The model uses logistic regression through Generalised Additive Models for Location, Scale and Shape (GAMLSS to determine the probability of flow occurring in any of the systems. We then use the same regression framework in combination with a right-skewed distribution, the Box-Cox t distribution, to model the intensity (depth of the non-zero streamflows. Time, seasonality and climate indices, describing the Pacific and Indian Ocean sea surface temperatures, are tested as covariates in the GAMLSS model to make probabilistic 12-month forecasts of the occurrence and intensity of streamflow. The output reveals that in the study region the occurrence and variability of flow is driven by sea surface temperatures and therefore forecasts can be made with some skill.

  4. Acute effects of cigarette smoking on inflammation in healthy intermittent smokers

    Directory of Open Access Journals (Sweden)

    Vonk Judith M

    2005-03-01

    Full Text Available Abstract Background Chronic smoking is the main risk factor for chronic obstructive pulmonary disease. Knowledge on the response to the initial smoke exposures might enhance the understanding of changes due to chronic smoking, since repetitive acute smoke effects may cumulate and lead to irreversible lung damage. Methods We investigated acute effects of smoking on inflammation in 16 healthy intermittent smokers in an open randomised cross-over study. We compared effects of smoking of two cigarettes on inflammatory markers in exhaled air, induced sputum, blood and urine at 0, 1, 3, 6, 12, 24, 48, 96 and 192 hours and outcomes without smoking. All sputum and blood parameters were log transformed and analysed using a linear mixed effect model. Results Significant findings were: Smoking increased exhaled carbon monoxide between 0 and 1 hour, and induced a greater decrease in blood eosinophils and sputum lymphocytes between 0 and 3 hours compared to non-smoking. Compared to non-smoking, smoking induced a greater interleukin-8 release from stimulated blood cells between 0 and 3 hours, and a greater increase in sputum lymphocytes and neutrophils between 3 and 12 hours. Conclusion We conclude that besides an increase in inflammation, as known from chronic smoking, there is also a suppressive effect of smoking two cigarettes on particular inflammatory parameters.

  5. Intermittency is a consequence of turbulent transport in nonlinear systems

    OpenAIRE

    Newell, Benno Rumpf Alan C.

    2003-01-01

    Intermittent high-amplitude structures emerge in a damped and driven discrete nonlinear Schroedinger equation whose solutions transport both energy and particles from sources to sinks. These coherent structures are necessary for any solution that has statistically stationary transport properties.

  6. Factors relevant to utility integration of intermittent renewable technologies

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Yih-huei; Parsons, B.K.

    1993-08-01

    This study assesses factors that utilities must address when they integrate intermittent renewable technologies into their power-supply systems; it also reviews the literature in this area and has a bibliography containing more than 350 listings. Three topics are covered: (1) interface (hardware and design-related interconnection), (2) operability/stability, and (3) planning. This study finds that several commonly held perceptions regarding integration of intermittent renewable energy technologies are not valid. Among findings of the study are the following: (1) hardware and system design advances have eliminated most concerns about interface; (2) cost penalties have not occurred at low to moderate penetration levels (and high levels are feasible); and (3) intermittent renewable energy technologies can have capacity values. Obstacles still interfering with intermittent renewable technologies are also identified.

  7. Sensing and characterization of EMI during intermittent connector anomalies

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper presents a new on-line methodology for detecting intermittent disconnection failures. The detection principle operates on the fundamental Lorentz Law...

  8. Isolated intermittent vertigo: A presenting feature of persistent trigeminal artery

    Directory of Open Access Journals (Sweden)

    Rajsrinivas Parthasarathy

    2016-01-01

    Full Text Available Embryonic carotid – basilar anastomosis when persistent in adult life can present with a variety of neurological symptoms. We present a patient with isolated intermittent vertigo attributable to the embryonic anastomosis and describe the different types of persistent trigeminal artery. A 76-year-old Caucasian man presented with isolated intermittent vertigo and symptoms suggestive of anterior and posterior circulation strokes. Impaired vasomotor reactivity was demonstrated on insonation of the anterior and posterior cerebral arteries in this patient with a persistent left trigeminal artery and 75% stenosis of the left internal carotid artery (ICA. The symptom of intermittent vertigo resolved with carotid endarterectomy. Decreased flow across the stenotic segment of the ICA which subserved the posterior circulation resulted in basilar insufficiency. Hypoperfusion to the flocculonodular lobe supplied by the anterior inferior cerebellar artery is a likely cause for the intermittent vertigo.

  9. Isolated intermittent vertigo: A presenting feature of persistent trigeminal artery

    Science.gov (United States)

    Parthasarathy, Rajsrinivas; Derksen, Carol; Saqqur, Maher; Khan, Khurshid

    2016-01-01

    Embryonic carotid – basilar anastomosis when persistent in adult life can present with a variety of neurological symptoms. We present a patient with isolated intermittent vertigo attributable to the embryonic anastomosis and describe the different types of persistent trigeminal artery. A 76-year-old Caucasian man presented with isolated intermittent vertigo and symptoms suggestive of anterior and posterior circulation strokes. Impaired vasomotor reactivity was demonstrated on insonation of the anterior and posterior cerebral arteries in this patient with a persistent left trigeminal artery and 75% stenosis of the left internal carotid artery (ICA). The symptom of intermittent vertigo resolved with carotid endarterectomy. Decreased flow across the stenotic segment of the ICA which subserved the posterior circulation resulted in basilar insufficiency. Hypoperfusion to the flocculonodular lobe supplied by the anterior inferior cerebellar artery is a likely cause for the intermittent vertigo. PMID:26933370

  10. Isolated intermittent vertigo: A presenting feature of persistent trigeminal artery.

    Science.gov (United States)

    Parthasarathy, Rajsrinivas; Derksen, Carol; Saqqur, Maher; Khan, Khurshid

    2016-01-01

    Embryonic carotid - basilar anastomosis when persistent in adult life can present with a variety of neurological symptoms. We present a patient with isolated intermittent vertigo attributable to the embryonic anastomosis and describe the different types of persistent trigeminal artery. A 76-year-old Caucasian man presented with isolated intermittent vertigo and symptoms suggestive of anterior and posterior circulation strokes. Impaired vasomotor reactivity was demonstrated on insonation of the anterior and posterior cerebral arteries in this patient with a persistent left trigeminal artery and 75% stenosis of the left internal carotid artery (ICA). The symptom of intermittent vertigo resolved with carotid endarterectomy. Decreased flow across the stenotic segment of the ICA which subserved the posterior circulation resulted in basilar insufficiency. Hypoperfusion to the flocculonodular lobe supplied by the anterior inferior cerebellar artery is a likely cause for the intermittent vertigo. PMID:26933370

  11. MUSCLE FIBER SPECIFIC ANTIOXIDATIVE SYSTEM ADAPTATION TO SWIM TRAINING IN RATS: INFLUENCE OF INTERMITTENT HYPOXIA

    Directory of Open Access Journals (Sweden)

    Olga Gonchar

    2005-06-01

    Full Text Available The aim of the present study was to examine the influence of intermittent hypoxia at rest and in combination with long-term high-intensity swimming exercise on lipid peroxidation and antioxidant defense system adaptation in skeletal muscles differing in fiber type composition. High-intensity chronic exercise was performed as swimming training with load that corresponded to ~ 75 % VO2max (30 min·day-1, 5 days·wk-1, for 4 wk. Intermittent hypoxic training (IHT consisted of repeated episodes of hypoxia (12%O2, 15 min, interrupted by equal periods of recovery (5 sessions/day, for 2 wk. Sessions of IHT were used during the first two weeks and during the last two weeks of chronic exercise. Oxidative (red gastrocnemius and soleus, mix and glycolytic (white gastrocnemius muscles were sampled. Our results indicated that high-intensity swim training in combination with sessions of IHT induced more profound antioxidative adaptations in skeletal muscles than the exercise training only. This adaptation has muscle fiber type specificity and is reflected in significantly elevated superoxide dismutase and catalase activities in highly oxidative muscle only. Training adaptation of GSH system (reduced glutathione content, activities of glutathione reductase, glutathione peroxidase, NADPH-supplying enzyme glucose-6-phosphate dehydrogenase occurred both in slow- and fast-twitch muscles. However, this process was more effective in oxidative muscles. IHT attenuated the increase in TBARS content induced by high-intensity swimming training. The test on exercise tolerance demonstrated a significant elevation of the swimming time to exhaustion after IHT at rest and after IHT in conjunction with high-intensity exercise in comparison with untrained and chronically exercised rats. These results confirmed that sessions of IHT might improve exercise tolerance and increase maximal work capacity

  12. Drift Intermittent Synchronization and Controllability in a Simple Model

    Institute of Scientific and Technical Information of China (English)

    XIE Bai-Song; YU Ming-Young

    2005-01-01

    A simple model of three coupled oscillators as an approximation of main modes behaviors in a spatial extended system is proposed. Multi-looping generalized synchronization and drift intermittent lag phase synchronization phenomena are found in this simple model. For a certain of parameters in which chaotic-like intermittent behavior exhibit the amplitudes and phases of three modes are controlled to be synchronized states via coupling them with an external periodic mode.

  13. Intermittent Turbulence in the Very Stable Ekman Layer

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, James C.

    2001-01-05

    INTERMITTENT TURBULENCE IN THE VERY STABLE EKMAN LAYER This study describes a Direct Numerical Simulation (DNS) of a very stable Ekman layer in which a constant downward heat flux is applied at the lower boundary, thus cooling the fluid above. Numerical experiments were performed in which the strength of the imposed heat flux was varied. For downward heat fluxes above a certain critical value the turbulence becomes intermittent and, as the heat flux increases beyond this value, the flow tends to relaminarize because of the very strong ambient stratification. We adopt Mahrt?s (1999) definition of the very stable boundary layer as a boundary layer in which intermittent, rather than continuous turbulence, is observed. Numerical experiments were used to test various hypothesis of where in ?stability parameter space? the very stable boundary layer is found. These experiments support the findings of Howell and Sun (1999) that the boundary layer will exhibit intermittency and therefore be categorized as ?very stable?, when the stability parameter, z/L, exceeds unity. Another marker for the very stable boundary layer, Derbyshire?s (1990) maximum heat flux criterion, was also examined. Using a case study drawn from the simulations where turbulence intermittency was observed, the mechanism that causes the intermittence was investigated. It was found that patchy turbulence originates from a vigorous inflectional, Ekman-like instability -- a roll cell -- that lifts colder air over warmer air. The resulting convective instability causes an intense burst of turbulence. This turbulence is short-lived because the lifting motion of the roll cell, as well as the roll cell itself, is partially destroyed after the patchy turbulence is generated. Examples of intermittent turbulence obtained from the simulations appear to be consistent with observations of intermittency even though the Reynolds number of the DNS is relatively low (400).

  14. The minimum transition hypothesis for intermittent hierarchical motor control

    Directory of Open Access Journals (Sweden)

    Amir eKarniel

    2013-02-01

    Full Text Available In intermittent control, instead of continuously calculating the control signal, the controller occasionally changes this signal at certain sparse points in time. The control law may include feedback, adaptation, optimization, or any other control strategies. When, where, and how does the brain employ intermittency as it controls movement? These are open questions in motor neuroscience. Evidence for intermittency in human motor control has been repeatedly observed in the neural control of movement literature. Moreover, some researchers have provided theoretical models to address intermittency. Even so, the vast majority of current models, and I would dare to say the dogma in most of the current motor neuroscience literature involves continuous control. In this paper, I focus on an area in which intermittent control has not yet been thoroughly considered, the structure of muscle synergies. A synergy in the muscle space is a group of muscles activated together by a single neural command. Under the assumption that the motor control is intermittent, I present the minimum transition hypothesis and its predictions with regards to the structure of muscle synergies. The minimum transitions hypothesis (MTH asserts that the purpose of synergies is to minimize the effort of the higher level in the hierarchy by minimizing the number of transitions in an intermittent control signal. The implications of the MTH are not only for the structure of the muscle synergies but also to the intermittent and hierarchical nature of the motor system, with various predictions as to the process of skill learning, and important implications to the design of brain machine interfaces and human robot interaction.

  15. Identification of intermittent control in man and machine

    OpenAIRE

    Loram, Ian D.; van de Kamp, Cornelis; Gollee, Henrik; Gawthrop, Peter J.

    2012-01-01

    Regulation by negative feedback is fundamental to engineering and biological processes. Biological regulation is usually explained using continuous feedback models from both classical and modern control theory. An alternative control paradigm, intermittent control, has also been suggested as a model for biological control systems, particularly those involving the central nervous system. However, at present, there is no identification method explicitly formulated to distinguish intermittent fr...

  16. Decarbonizing electricity generation with intermittent sources of energy

    OpenAIRE

    Ambec, Stefan; Crampes, Claude

    2015-01-01

    We examine the impact of public policies that aim to decarbonate electricity production by replacing fossil fuel energy by intermittent renewable sources, namely wind and solar power. We consider a model of energy investment and production with two sources of energy: one is clean but intermittent (e.g. wind), whereas the other one is reliable but polluting (e.g. coal). A carbon tax decreases electricity production while simultaneously increasing investment in wind power. This tax may however ...

  17. INTERMITTENT CLONAZEPAM IN THE PREVENTION OF RECURRENT FEBRILE SEIZURES

    OpenAIRE

    Touran MAHMOUDIAN; Omid YAGHINI; Shirin BAJOGHLI

    2010-01-01

    ObjectiveTo evaluate the efficacy and common side effects of intermittent clonazepam in febrile  seizures.Materials & MethodsThis study was an experimental trial designed to determine the efficacy of intermittent clonazepam in febrile seizures .Thirty patients with an age range of 6 months to 5 years (60% male, 40% female) were studied. Children with a history of psychomotor delay, abnormal  neurological examination, a history of antiepileptic drug consumption, and afebrile seizures were excl...

  18. Non-locality and Intermittency in 3D Turbulence

    OpenAIRE

    Laval, J. -P.; B. Dubrulle; Nazarenko, S.(Russian Federal Nuclear Center (VNIIEF), Sarov, Russia)

    2001-01-01

    Numerical simulations are used to determine the influence of the non-local and local interactions on the intermittency corrections in the scaling properties of 3D turbulence. We show that neglect of local interactions leads to an enhanced small-scale energy spectrum and to a significantly larger number of very intense vortices (tornadoes) and stronger intermittency. On the other hand, neglect of the non-local interactions results in even stronger small-scale spectrum but significantly weaker ...

  19. Acute Intermittent Porphyria Associated with Respiratory Failure: A Multidisciplinary Approach

    OpenAIRE

    Mayra Gonçalves Menegueti; Alkmim-Teixeira Gil Cezar; Karin Aparecida Casarini; Kátia Simone Muniz Cordeiro; Anibal Basile-Filho; Olindo Assis Martins-Filho; Maria Auxiliadora-Martins

    2011-01-01

    Despite being challenging, delivery of effective nursing care to patients with acute intermittent porphyria is a matter of utmost importance. In this paper, the diversity of symptoms and the difficult diagnosis of this condition are emphasized, and details concerning the treatment of this disorder in the intensive care unit are presented. We believe that acute intermittent porphyria should be borne in mind during performance of differential diagnosis of neurological, psychiatric, and gastroen...

  20. Critical velocity during continuous and intermittent exercises in children.

    Science.gov (United States)

    Berthoin, Serge; Baquet, Georges; Dupont, Gregory; Van Praagh, Emmanuel

    2006-09-01

    The purpose of this study was to apply the "critical velocity" concept to short intermittent high-intensity running exercises in prepubescent girls and boys and to compare the running performances obtained either by intermittent or continuous exercise runs. Eleven 8 to 11-year-old children underwent a maximal graded field test to determine peak oxygen uptake (peakVO2) and maximal aerobic velocity (MAV). During the six following sessions, they randomly performed three continuous runs (90, 100, and 110% of MAV) and three intermittent runs (120, 130, and 140% of MAV) until exhaustion. Intermittent exercises consisted of repeated 15 s runs each one separated by a 15 s passive recovery interval. For continuous as well as intermittent exercises, distance versus time to exhaustion (TTE) relationships were calculated to determine continuous (CVc) and intermittent (CVi) critical velocities. Values for peakVO2 and MAV were 45.8 +/- 5.3 ml x kg(-1) x min(-1) and 10.5 +/- 1.0 km h(-1), respectively. For the whole population, a significant relationship was found between the distance to exhaustion (DTE) and TTE for continuous (r2= 0.99, P < 0.05) and intermittent exercises (r2 = 0.99, P < 0.05). Significant relationships were found between peakVO2 and both CVc (r2= 0.60, P < 0.01) and CVi (r2= 0.47, P < 0.05). In conclusion, as for continuous exercises, a linear relationship was found between DTE and TTE for short high-intensity intermittent exercises. CVc was significantly related to peakVO2, while a significant lower relationship was found between peakVO2 and CVi.

  1. The Prismatic Effect on Stereoacuity in Intermittent Exotropia

    OpenAIRE

    Choi, Kyoung Sub; Chung, Seung Ah; Lee, Kyu Sung; Lee, Jong Bok

    2009-01-01

    Purpose To evaluate the effect of acrylic refractive prism and Fresnel membrane prism on stereoacuity in intermittent exotropia. Materials and Methods Stereoacuities of fifty-two patients (mean age, 12.4 years; range 6 to 45 years) with intermittent exotropia were measured using the Titmus and TNO stereotests, while they wore prisms of varying power on nonfixating eye or evenly on each eye. Results Stereoacuities were significantly reduced with increasing prism power for both prisms, ranging ...

  2. Regionalization of patterns of flow intermittence from gauging station records

    OpenAIRE

    Snelder, T.H.; Datry, T.; Lamouroux, N.; Larned, S. T.; E. Sauquet; Pella, H.; C. Catalogne

    2013-01-01

    Understanding large-scale patterns in flow intermittence is important for effective river management. The duration and frequency of zero-flow periods are associated with the ecological characteristics of rivers and have important implications for water resources management. We used daily flow records from 628 gauging stations on rivers with minimally modified flows distributed throughout France to predict regional patterns of flow intermittence. For each station we calculated two annual times...

  3. Regionalization of patterns of flow intermittence from gauging station records

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    T. H. Snelder

    2013-07-01

    Full Text Available Understanding large-scale patterns in flow intermittence is important for effective river management. The duration and frequency of zero-flow periods are associated with the ecological characteristics of rivers and have important implications for water resources management. We used daily flow records from 628 gauging stations on rivers with minimally modified flows distributed throughout France to predict regional patterns of flow intermittence. For each station we calculated two annual times series describing flow intermittence; the frequency of zero-flow periods (consecutive days of zero flow in each year of record (FREQ; yr−1, and the total number of zero-flow days in each year of record (DUR; days. These time series were used to calculate two indices for each station, the mean annual frequency of zero-flow periods (mFREQ; yr−1, and the mean duration of zero-flow periods (mDUR; days. Approximately 20% of stations had recorded at least one zero-flow period in their record. Dissimilarities between pairs of gauges calculated from the annual times series (FREQ and DUR and geographic distances were weakly correlated, indicating that there was little spatial synchronization of zero flow. A flow-regime classification for the gauging stations discriminated intermittent and perennial stations, and an intermittence classification grouped intermittent stations into three classes based on the values of mFREQ and mDUR. We used random forest (RF models to relate the flow-regime and intermittence classifications to several environmental characteristics of the gauging station catchments. The RF model of the flow-regime classification had a cross-validated Cohen's kappa of 0.47, indicating fair performance and the intermittence classification had poor performance (cross-validated Cohen's kappa of 0.35. Both classification models identified significant environment-intermittence associations, in particular with regional-scale climate patterns and also

  4. Intermittency and Topology of Shock Induced Mixing

    Science.gov (United States)

    Tellez, Jackson; Redondo, Jose M.; Ben Mahjoub, Otman; Malik, Nadeem; Vila, Teresa

    2016-04-01

    The advance of a Rayleigh-Taylor front is described in Linden & Redondo (1991),[1-3] and may be shown to follow a quadratic law in time where the width of the growing region of instability depends on the local mixing efficiency of the different density fluids that accelerate against each other g is the acceleration and A is the Atwood number defined as the diference of densities divided by their sum. This results show the independence of the large amplitude structures on the initial conditions the width of the mixing region depends also on the intermittency of the turbulence. Then dimensional analysis may also depend on the relevant reduced acceleration driven time and the molecular reactive time akin to Damkholer number and the fractal structure of the contact zone [2,4]. Detailed experiments and simulations on RT and RM shock induced fronts analized with respect to structure functions are able to determine which mechanisms are most effective in local mixing which increase the effective fractal dimension, as well as the effect of higher order geometrical parameters, such as the structure functions, in non-homogeneous fluids (Mahjoub et al 1998)[5]. The structure of a Mixing blob shows a relatively sharp head with most of the mixing taking place at the sides due to what seems to be shear instability very similar to the Kelvin-Helmholtz instabilities, but with sideways accelerations. The formation of the blobs and spikes with their secondary instabilities produces a turbulent cascade, evident just after about 1 non-dimensional time unit, from a virtual time origin that takes into account the linear growth phase, as can be seen by the growth of the fractal dimension for different volume fractions. Two-dimensional cuts of the 3D flow also show that vortex flows have closed or spiral streamlines around their core. Examples of such flows can be also seen in the laboratory, for example at the interface of atwo-layer stratified fluid in a tank in which case streamlines

  5. Run-Off Computed Tomography Angiography (CTA) for Discriminating the Underlying Causes of Intermittent Claudication

    Science.gov (United States)

    Werncke, Thomas; Steffen, Ingo G.; Hamm, Bernd; Elgeti, Thomas

    2016-01-01

    Aim To evaluate run-off computed tomography angiography (CTA) of abdominal aorta and lower extremities for detecting musculoskeletal pathologies and clinically relevant extravascular incidental findings in patients with intermittent claudication (IC) and suspected peripheral arterial disease (PAD). Does run-off CTA allow image-based therapeutic decision making by discriminating the causes of intermittent claudication in patients with suspected peripheral arterial disease PAD? Material and Methods Retrospective re-evaluation of CTAs performed in patients with acute or chronic intermittent claudication (i.e., Fontaine stages I to IIB) between January 2005 and October 2013. Allocation to one of three categories of underlying causes of IC symptoms: vascular, musculoskeletal (MSK) or both. Clinically relevant extravascular incidental findings were evaluated. Medical records were reviewed to verify specific therapies as well as main and incidental findings. Results While focused on vascular imaging, CTA image quality was sufficient for evaluation of the MSK system in all cases. The underlying cause of IC was diagnosed in run-off CTA as vascular, MSK and a combination in n = 138 (65%), n = 10 (4%), and n = 66 (31%) cases, respectively. Specific vascular or MSK therapy was recorded in n = 123 and n = 9 cases. In n = 82, no follow-up was possible. Clinically relevant extravascular incidental findings were detected in n = 65 patients (30%) with neoplasia, ascites and pleural effusion being the most common findings. Discussion Run-off CTA allows identification of vascular, MSK, and combined causes of IC in patients with suspected PAD and can guide specific therapy. CTA also allowed confident detection of crEVIF although detection did not necessarily trigger workup or treatment. PMID:27054846

  6. Run-Off Computed Tomography Angiography (CTA for Discriminating the Underlying Causes of Intermittent Claudication.

    Directory of Open Access Journals (Sweden)

    Alexandra Preuß

    Full Text Available To evaluate run-off computed tomography angiography (CTA of abdominal aorta and lower extremities for detecting musculoskeletal pathologies and clinically relevant extravascular incidental findings in patients with intermittent claudication (IC and suspected peripheral arterial disease (PAD. Does run-off CTA allow image-based therapeutic decision making by discriminating the causes of intermittent claudication in patients with suspected peripheral arterial disease PAD?Retrospective re-evaluation of CTAs performed in patients with acute or chronic intermittent claudication (i.e., Fontaine stages I to IIB between January 2005 and October 2013. Allocation to one of three categories of underlying causes of IC symptoms: vascular, musculoskeletal (MSK or both. Clinically relevant extravascular incidental findings were evaluated. Medical records were reviewed to verify specific therapies as well as main and incidental findings.While focused on vascular imaging, CTA image quality was sufficient for evaluation of the MSK system in all cases. The underlying cause of IC was diagnosed in run-off CTA as vascular, MSK and a combination in n = 138 (65%, n = 10 (4%, and n = 66 (31% cases, respectively. Specific vascular or MSK therapy was recorded in n = 123 and n = 9 cases. In n = 82, no follow-up was possible. Clinically relevant extravascular incidental findings were detected in n = 65 patients (30% with neoplasia, ascites and pleural effusion being the most common findings.Run-off CTA allows identification of vascular, MSK, and combined causes of IC in patients with suspected PAD and can guide specific therapy. CTA also allowed confident detection of crEVIF although detection did not necessarily trigger workup or treatment.

  7. Intermittent noninvasive ventilation at San José Hospital in Chile: report of a German donation.

    Science.gov (United States)

    Arellano Maric, M P; Roldán Toledo, R; Huttmann, S E; Storre, J H; Windisch, W

    2015-03-01

    Home mechanical ventilation is currently expanding in Chile, but its application along the country is hindered by financial and geographical reasons. In 2006 the San José Hospital in Santiago de Chile developed a non-invasive ventilation (NIV) center as a strategy to overcome the limitations of ventilator availability from public resources. Since then, this center provides intermittent diurnal sessions of NIV to patients with chronic hypercapnic respiratory failure. In 2013, a collaboratory work between the Chilean doctors, the German Interdisciplinary Society of Home Mechanical Ventilation (DIGAB = Deutsche Interdisziplinäre Gesellschaft für Außerklinische Beatmung) and the German non-invasive (NIV) home care provider "Heinen und Löwenstein" organized a donation of 100 second-hand ventilators (BiPAP Synchrony; Respironics, USA) including masks and tubing systems, which were provided by Heinen und Löwenstein. The ventilator devices arrived in Santiago in January 2014. Since then, the following initiatives have been launched: 1) the establishment of a domiciliary mechanical ventilation program independent of governmental founding, 2) NIV setting-titration, 3) renewal of ventilators at the hospital's intermittent NIV unit. Future goals are the establishment of a rehabilitation unit with concomitant NIV therapy and a clinical research program. Therefore, the German donation of ventilators and equipment has a reported impact on the development of NIV in Chile. PMID:25629262

  8. Enhanced carotid body chemosensory activity and the cardiovascular alterations induced by intermittent hypoxia

    Directory of Open Access Journals (Sweden)

    Rodrigo eIturriaga

    2014-12-01

    Full Text Available The carotid body (CB plays a main role in the maintenance of the oxygen homeostasis. The hypoxic stimulation of the CB increases the chemosensory discharge, which in turn elicits reflex sympathetic, cardiovascular and ventilatory adjustments. An exacerbate carotid chemosensory activity has been associated with human sympathetic-mediated diseases such as hypertension, insulin resistance, heart failure and obstructive sleep apnea (OSA. Indeed, the CB chemosensory discharge becomes tonically hypereactive in experimental models of OSA and heart failure. Chronic intermittent hypoxia (CIH, a main feature of OSA, enhances CB chemosensory baseline discharges in normoxia and in response to hypoxia, inducing sympathetic overactivity and hypertension. Oxidative stress, increased levels of ET-1, Angiotensin II and pro-inflammatory cytokines, along with a reduced production of NO in the CB, have been associated with the enhanced carotid chemosensory activity. In this review, we will discuss new evidence supporting a main role for the CB chemoreceptor in the autonomic and cardiorespiratory alterations induced by intermittent hypoxia, as well as the molecular mechanisms involved in the CB chemosensory potentiation.

  9. Intermittent attendance at breast cancer screening

    Directory of Open Access Journals (Sweden)

    Padraic Fleming

    2013-09-01

    Full Text Available Background. To determine why women skip rounds and factors influencing return of previous non attenders (PNAs to breast screening. Design and methods. Retrospective, quantitative, structured questionnaire posted to 2500 women. First PNAs did not attend their first screening appointment in 2007/2008 but then attended in 2010; First Controls first attended in 2010 without missed previous appointments. Women who attended screening in 2006 or earlier then skipped a round but returned in 2010 were Subsequent PNAs; Subsequent Controls attended all appointments.Results. More First Controls than First PNAs had family history of cancer (72.7% vs 63.2%; P=0.003; breast cancer (31.3% vs 24.8%; P=0.04. More PNAs lived rurally; more First PNAs had 3rd level education (33.2% vs 23.6%; P=0.002 and fewer had private insurance than First Controls (57.7% vs 64.8%; P=0.04. Excellent/good health was reported in First PNAs and First Controls (82.9% vs 83.2%, but fewer Subsequent PNAs than Subsequent Controls (72.7% vs 84.9%; P=0.000. Common considerations at time of missed appointment were had mammogram elsewhere (33% First PNA and postponed to next round (16% First PNA, 18.8% Subsequent PNA. Considerations when returning to screening were similar for First PNAs and Subsequent PNAs: I am older (35.4%, 29.6%, I made sure I remembered (29%, 23.6%, could reschedule (17.6%, 20.6%, illness of more concern (16.5%, 19%. More First PNAs stated my family/friends advised (22.3% vs 15.2% or my GP (12.6% vs 4.6% advised me to attend, heard good things about BreastCheck (28.8% vs 13.6%.Conclusions. Intermittent attenders do not fit socio-demographic patterns of non-attenders; GP recommendation and word of mouth were important in women’s return to screening. Fear and anxiety seem to act as a screening facilitator rather than an inhibitor.

  10. Deletion of Metallothionein Exacerbates Intermittent Hypoxia-Induced Oxidative and Inflammatory Injury in Aorta

    Directory of Open Access Journals (Sweden)

    Shanshan Zhou

    2014-01-01

    Full Text Available The present study was to explore the effect of metallothionein (MT on intermittent hypoxia (IH induced aortic pathogenic changes. Markers of oxidative damages, inflammation, and vascular remodeling were observed by immunohistochemical staining after 3 days and 1, 3, and 8 weeks after IH exposures. Endogenous MT was induced after 3 days of IH but was significantly decreased after 8 weeks of IH. Compared with the wild-type mice, MT knock-out mice exhibited earlier and more severe pathogenic changes of oxidative damages, inflammatory responses, and cellular apoptosis, as indicated by the significant accumulation of collagen, increased levels of connective tissue growth factor, transforming growth factor β1, tumor necrosis factor-alpha, vascular cell adhesion molecule 1,3-nitrotyrosine, and 4-hydroxy-2-nonenal in the aorta. These findings suggested that chronic IH may lead to aortic damages characterized by oxidative stress and inflammation, and MT may play a pivotal role in the above pathogenesis process.

  11. Intermittency on simultaneous observations of riometer at several Antarctic locations

    Science.gov (United States)

    Ovalle, E. M.; Foppiano, A. J.; Stepanova, M. V.; Weatherwax, A. T.

    2016-03-01

    It is well known that auroral radio wave absorption, as measured by riometers, consists of periods of relative quiescence which are interrupted by short bursts of activity. Such patterns in activity are observed in systems ranging from the stock market to turbulence, i.e. they exhibit intermittency. In the case of the auroral absorption it has also been found that intermittency strongly depends on the magnetic local time, being largest in the night-time sector. This can be interpreted as indicating that the precipitating particles responsible of the absorption exhibit intermittency, especially near the substorm eye, where the level of turbulence increases. Here, we analyse simultaneous observations of riometer absorption at seven Antarctic locations, to determine whether they exhibit intermittency. We determine the Probability Distribution Functions of the fluctuations of riometer absorption for absorption events larger than 0.1 dB, as well as those for the time-intervals between absorption events. Observations are for locations within the austral auroral absorption zone and on the polar cap. It is found that the parameters of a power law used to describe the calculated PDFs are consistent with the formation of coherent structures being more frequent within the auroral zone, as a manifestation of intermittency.

  12. Mathematically modelling and controlling prostate cancer under intermittent hormone therapy

    Institute of Scientific and Technical Information of China (English)

    Yoshito Hirata; Gouhei Tanaka; Nicholas Bruchovsky; Kazuyuki Aihara

    2012-01-01

    In this review,we summarize our recently developed mathematical models that predict the effects of intermittent androgen suppression therapy on prostate cancer (PCa).Although hormone therapy for PCa shows remarkable results at the beginning of treatment,cancer cells frequently acquire the ability to grow without androgens during long-term therapy,resulting in an eventual relapse.To circumvent hormone resistance,intermittent androgen suppression was investigated as an alternative treatment option.However,at the present time,it is not possible to select an optimal schedule of on- and off-treatment cycles for any given patient.In addition,clinical trials have revealed that intermittent androgen suppression is effective for some patients but not for others.To resolve these two problems,we have developed mathematical models for PCa under intermittent androgen suppression.The mathematical models not only explain the mechanisms of intermittent androgen suppression but also provide an optimal treatment schedule for the on- and off-treatment periods.

  13. Entropic-Skins Geometry to Describe Wall Turbulence Intermittency

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    Diogo Queiros-Conde

    2015-04-01

    Full Text Available In order to describe the phenomenon of intermittency in wall turbulence and, more particularly, the behaviour of moments  and and intermittency exponents ζP with the order p and distance to the wall, we developed a new geometrical framework called “entropic-skins geometry” based on the notion of scale-entropy which is here applied to an experimental database of boundary layer flows. Each moment has its own spatial multi-scale support Ωp (“skin”. The model assumes the existence of a hierarchy of multi-scale sets Ωp ranged from the “bulk” to the “crest”. The crest noted characterizes the geometrical support where the most intermittent (the highest fluctuations in energy dissipation occur; the bulk is the geometrical support for the whole range of fluctuations. The model assumes then the existence of a dynamical flux through the hierarchy of skins. The specific case where skins display a fractal structure is investigated. Bulk fractal dimension  and crest dimension  are linked by a scale-entropy flux defining a reversibility efficiency  (d is the embedding dimension. The model, initially developed for homogeneous and isotropic turbulent flows, is applied here to wall bounded turbulence where intermittency exponents are measured by extended self-similarity. We obtained for intermittency exponents the analytical expression with γ ≈ 0.36 in agreement with experimental results.

  14. Study on Intermittent Irrigation for Paddy Rice: II. Crop Responses

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Effect of intermittent irrigation on the production of paddy rice was studied in a well-puddled paddy field with four treatments and 2 replicates: continuous flooding irrigation (CFI), and intermittent irrigation II-0, II-1 and II-2, in which plants were re-irrigated when the soil water potential fell below 0, -10, and -20 kPa, respectively, at soil depth of about 5 cm. Results showed that the reduction in soil water potential to about -10 or -20 kPa did not significantly affect the number of grains and the percentage of ripened grains. While, a lower crop growth rate (CGR) resulted from a decrease in the net assimilation rate (NAR) during intermittent irrigation II-1 and II-2, and there was also a reduction in the leaf area index (LAI) during intermittent irrigation II-2. Senescence of lower leaves on stems was promoted in treatments II-1 and II-2 at the ripening stage. Early senescence at ripening stage and water stress around midday decreased the rate of photosynthesis in leaves, causing the lower NAR. These physiological responses of the plants were responsible for the reduction in the dry matter production and grain yield in the intermittent irrigation treatments.

  15. Scaling the Thrust Production and Energetics of Inviscid Intermittent Swimming

    Science.gov (United States)

    Akoz, Emre; Moored, Keith

    2015-11-01

    Many fish have adopted an intermittent swimming gait sometimes referred as a burst-and-coast behavior. By using this gait, fish have been estimated at reducing their energetic cost of swimming by about 50%. Lighthill proposed that the skin friction drag of an undulating body can be around 400% greater than a rigidly-held coasting body, which may explain the energetic savings of intermittent swimming. Recent studies have confirmed the increase in skin friction drag over an undulating body, however, the increase is on the order of 20-70%. This more modest gain in skin friction drag is not sufficient to lead to the observed energy savings. Motivated by these observations, we investigate the inviscid mechanisms behind intermittent swimming for parameters typical of biology. We see that there is an energy savings at a fixed swimming speed for intermittent swimming as compared to continuous swimming. Then we consider three questions: What is the nature of the inviscid mechanism that leads to the observed energy savings, how do the forces and energetics of intermittent swimming scale with the swimming parameters, and what are the limitations to the benefit? Supported by the Office of Naval Research under Program Director Dr. Bob Brizzola, MURI grant number N00014-14-1-0533.

  16. Subacute fulminant hepatic failure with intermittent fever

    Institute of Scientific and Technical Information of China (English)

    Cong-Xin Chen; Bo Liu; Yong Hu; Joyce E. Johnson; Yi-Wei Tang

    2009-01-01

    BACKGROUND:Viral hepatitis B accounts for over 80%of acute hepatic failures in China and the patients die mainly of its complications. A patient with hepatic failure and fever is not uncommon, whereas repeated fever is rare. METHODS:A 32-year-old female was diagnosed with subacute hepatic failure and hepatitis B viral infection because of hyperbilirubinemia, coagulopathy, hepatic encephalopathy, serum anti-HBs-positive without hepatitis B vaccination, and typical intrahepatic pathological features of chronic hepatitis B. Plasma exchange was administered twice and she awoke with hyperbilirubinemia and discontinuous fever. RESULTS:Urethritis was conifrmed and medication-induced fever and/or spontaneous bacterial peritonitis (Gram-negative bacillus infection) was suspected. The patient was treated with antibiotics, steroids and a Chinese herbal medicine, matrine, for three months and she recovered. CONCLUSION:The survival rate of patients with hepatic failure might be improved with comprehensive supporting measures and appropriate, timely management of com-plications.

  17. Cardioprotective adaptation of rats to intermittent hypobaric hypoxia is accompanied by the increased association of hexokinase with mitochondria.

    Science.gov (United States)

    Waskova-Arnostova, Petra; Elsnicova, Barbara; Kasparova, Dita; Hornikova, Daniela; Kolar, Frantisek; Novotny, Jiri; Zurmanova, Jitka

    2015-12-15

    Chronic hypoxia increases the myocardial resistance to acute ischemia-reperfusion injury by affecting the mitochondrial redox balance. Hexokinase (HK) bears a high potential to suppress the excessive formation of reactive oxygen species because of its increased association with mitochondria, thereby inhibiting the membrane permeability transition pore opening and preventing cell death. The purpose of this study was to determine the effect of severe intermittent hypobaric hypoxia (7,000 m, 8 h/day, 5 wk) on the function and colocalization of HK isoforms with mitochondria in the left (LV) and right ventricles of rat myocardium. The real-time RT-PCR, Western blot, enzyme coupled assay, and quantitative immunofluorescence techniques were used. Our results showed significantly elevated expression of HK isoforms (HK1 and HK2) in the hypoxic LV. In addition, intermittent hypoxia increased the total HK activity and the association of HK isoforms with mitochondria in both ventricles. These findings suggest that HK may contribute to the cardioprotective phenotype induced by adaptation to severe intermittent hypobaric hypoxia. PMID:26494452

  18. Intermittency in e+e- and lepton-hadron collisions

    International Nuclear Information System (INIS)

    The intermittency data in e+e- and lepton-hadron collisions are reviewed. The power-law behavior of the moments has been established by various e+e- experiments and a μp experiment. The intermittency in the two-dimensional space of rapidity and azimuthal angle is much stronger than in the rapidity space only. The neutrino-nucleus data indicate significant effects from nuclear reinteractions. The LUND parton shower model fits the data better than the matrix element model without special retuning. The relations among the moments of different orders are in good agreement with the predictions by the negative binomial and pure birth distributions. The origin of the intermittency in e+e- and μp collisions is consistent with the self-similar cascade mechanism of jet formation. 11 refs., 7 figs

  19. Multiparticle correlations and intermittency in high energy collisions

    CERN Document Server

    Bozek, P

    1992-01-01

    In this work the analysis of the intermittency signal observed in high energy experi- ments is done using multiparticle distributions and correlation functions. The effect of the dimensional projection of the multiparticle distributions on one or two-dimensional subspace is discussed. The structure of the multiparticle cumulants is analyzed for the DELPHI e + e~ annihilation data. The language of the self-similar distribution func- tions, which is used in this work, is shown to be largely equivalent to the well known a-model. In the case of the ultrarelativistic nuclear collisions, where the Monte-Carlo simulations fail to reproduce the data, we argue that the observed intermittency pattern is a signal of some nonlinear effect beyond the simple superposition of nucleon-nucleon collisions. The model of spatiotemporal intermittency is discussed in details and is shown to reproduce qualitatively the dependence of t...

  20. Multiparticle correlations and intermittency in high energy collisions

    International Nuclear Information System (INIS)

    The analysis of the intermittency signal observed in high energy experiments is presented using multiparticle distributions and correlation functions. The effect of the dimensional projection of the multiparticle distributions on one or two-dimensional subspace is discussed. The structure of the multiparticle cumulants is analyzed for the DELPHI e+e- annihilation data. The model of spatiotemporal intermittency is discussed in details and is shown to reproduce qualitatively the dependence of the intermittency strength on the target and projectile nuclei. A 1-dimensional (1D) cellular-automaton and a 1D forest-fire model is studied. On the example of the noncritical 1D Ising model the difficulties of the scaled factorial moment (SFM) method in extracting genuine scaling behaviour is illustrated. All these studies could serve as tools to test the sensibility of the SFM method as used in the analysis of the high energy production. (K.A.) 122 refs.; 38 figs.; 3 tabs

  1. Temporal intermittency of energy dissipation in magnetohydrodynamic turbulence.

    Science.gov (United States)

    Zhdankin, Vladimir; Uzdensky, Dmitri A; Boldyrev, Stanislav

    2015-02-13

    Energy dissipation in magnetohydrodynamic (MHD) turbulence is known to be highly intermittent in space, being concentrated in sheetlike coherent structures. Much less is known about intermittency in time, another fundamental aspect of turbulence which has great importance for observations of solar flares and other space or astrophysical phenomena. In this Letter, we investigate the temporal intermittency of energy dissipation in numerical simulations of MHD turbulence. We consider four-dimensional spatiotemporal structures, "flare events," responsible for a large fraction of the energy dissipation. We find that although the flare events are often highly complex, they exhibit robust power-law distributions and scaling relations. We find that the probability distribution of dissipated energy has a power-law index close to α≈1.75, similar to observations of solar flares, indicating that intense dissipative events dominate the heating of the system. We also discuss the temporal asymmetry of flare events as a signature of the turbulent cascade.

  2. Bladder emptying by intermittent electrical stimulation of the pudendal nerve

    Science.gov (United States)

    Boggs, Joseph W.; Wenzel, Brian J.; Gustafson, Kenneth J.; Grill, Warren M.

    2006-03-01

    Persons with a suprasacral spinal cord injury cannot empty their bladder voluntarily. Bladder emptying can be restored by intermittent electrical stimulation of the sacral nerve roots (SR) to cause bladder contraction. However, this therapy requires sensory nerve transection to prevent dyssynergic contraction of the external urethral sphincter (EUS). Stimulation of the compound pudendal nerve trunk (PN) activates spinal micturition circuitry, leading to a reflex bladder contraction without a reflex EUS contraction. The present study determined if PN stimulation could produce bladder emptying without nerve transection in cats anesthetized with α-chloralose. With all nerves intact, intermittent PN stimulation emptied the bladder (64 ± 14% of initial volume, n = 37 across six cats) more effectively than either distention-evoked micturition (40 ± 19%, p 0.10), indicating that PN stimulation was not limited by bladder-sphincter dyssynergia. Intermittent PN stimulation holds promise for restoring bladder emptying following spinal injury without requiring nerve transection.

  3. Intermittency in Fractal Fourier Hydrodynamics: Lessons from the Burgers Equation

    CERN Document Server

    Buzzicotti, Michele; Frisch, Uriel; Ray, Samriddhi Sankar

    2016-01-01

    We present theoretical and numerical results for the one-dimensional stochastically forced Burgers equation decimated on a fractal Fourier set of dimension $D$. We investigate the robustness of the energy transfer mechanism and of the small-scale statistical fluctuations by changing $D$. We find that a very small percentage of mode-reduction ($D \\lesssim 1$) is enough to destroy most of the characteristics of the original non-decimated equation. In particular, we observe a suppression of intermittent fluctuations for $D <1$ and a quasi-singular transition from the fully intermittent ($D=1$) to the non-intermittent case for $D \\lesssim 1$. Our results indicate that the existence of strong localized structures (shocks) in the one-dimensional Burgers equation is the result of highly entangled correlations amongst all Fourier modes.

  4. Generalized description of intermittency in turbulence via stochastic methods

    CERN Document Server

    Friedrich, J

    2016-01-01

    We present a generalized picture of intermittency in turbulence that is based on the theory of stochastic processes. To this end, we rely on the experimentally and numerically verified finding by R.~Friedrich and J.~Peinke [Phys. Rev. Lett. 78, 863 (1997)] that allows for an interpretation of the turbulent energy cascade as a Markov process of the velocity increments in scale. It is explicitly shown that all known phenomenological models of turbulence can be reproduced by the Kramers-Moyal expansion of the velocity increment probability density function that is associated to a Markov process. We compare the different sets of Kramers-Moyal coefficients of each phenomenology and deduce that an accurate description of intermittency should take into account an infinite number of coefficients. This is demonstrated in more detail for the case of Burgers turbulence that exhibits the strongest intermittency effects. Moreover, the influence of nonlocality on the Kramers-Moyal coefficients is investigated by direct num...

  5. Temporal Intermittency of Energy Dissipation in Magnetohydrodynamic Turbulence

    CERN Document Server

    Zhdankin, Vladimir; Boldyrev, Stanislav

    2015-01-01

    Energy dissipation in magnetohydrodynamic (MHD) turbulence is known to be highly intermittent in space, being concentrated in sheet-like coherent structures. Much less is known about intermittency in time, another fundamental aspect of turbulence which has great importance for observations of solar flares and other space/astrophysical phenomena. In this Letter, we investigate the temporal intermittency of energy dissipation in numerical simulations of MHD turbulence. We consider four-dimensional spatiotemporal structures, "flare events", responsible for a large fraction of the energy dissipation. We find that although the flare events are often highly complex, they exhibit robust power-law distributions and scaling relations. We find that the probability distribution of dissipated energy has a power law index close to -1.75, similar to observations of solar flares, indicating that intense dissipative events dominate the heating of the system. We also discuss the temporal asymmetry of flare events as a signatu...

  6. Scenedesmus dimorphus biofilm: Photoefficiency and biomass production under intermittent lighting.

    Science.gov (United States)

    Toninelli, Andrea Efrem; Wang, Junfeng; Liu, Mingshen; Wu, Hong; Liu, Tianzhong

    2016-01-01

    This study investigated the effect of intermittent lighting on the growth performances of a Scenedesmus dimorphus biofilm. Flashing light effect (FLE) is common in traditional suspended cultures of microalgae; yet, publications about this phenomenon, in the context of biofilm cultivation, are scarce. In this work we demonstrate that, thanks to intermittent illumination, it is possible for attached cultivations to fulfill FLE, improve photoefficiency and productivity as well as providing protection from photoinhibition using much lower flashing light frequencies than those usually required with suspended cultures. Medium frequency intermittent lighting (0.1 Hz) guaranteed excellent light integration resulting in 9.13 g m(-2) d(-1) biomass productivity, which was 8.9% higher than with continuous lighting. Results showed that a light fraction value of 0.5 always improved photoefficiency values as related to continuous light with a 118.8% maximum increase. PMID:27561323

  7. Intermittent hypoxia maintains glycemia in streptozotocin-induced diabetic rats.

    Science.gov (United States)

    Chen, Xiaofei; Zhao, Tong; Huang, Xin; Wu, Liying; Wu, Kuiwu; Fan, Ming; Zhu, Lingling

    2016-05-01

    Increasing studies have shown protective effects of intermittent hypoxia on brain injury and heart ischemia. However, the effect of intermittent hypoxia on blood glucose metabolism, especially in diabetic conditions, is rarely observed. The aim of this study was to investigate whether intermittent hypoxia influences blood glucose metabolism in type 1 diabetic rats. Streptozotocin-induced diabetic adult rats and age-matched control rats were treated with intermittent hypoxia (at an altitude of 3 km, 4 h per day for 3 weeks) or normoxia as control. Fasting blood glucose, body weight, plasma fructosamine, plasma insulin, homeostasis model assessment of insulin resistance (HOMA-IR), pancreas β-cell mass, and hepatic and soleus glycogen were measured. Compared with diabetic rats before treatment, the level of fasting blood glucose in diabetic rats after normoxic treatment was increased (19.88 ± 5.69 mmol/L vs. 14.79 ± 5.84 mmol/L, p  0.05). Meanwhile, fasting blood glucose in diabetic rats after hypoxic treatment was also lower than that in diabetic rats after normoxic treatment (13.14 ± 5.77 mmol/L vs. 19.88 ± 5.69 mmol/L, pintermittent hypoxia was significantly lower than that in diabetic rats receiving normoxia (1.28 ± 0.11 vs. 1.39 ± 0.11, p intermittent hypoxia showed effect on the increase of soleus glycogen but not hepatic glycogen. We conclude that intermittent hypoxia maintains glycemia in streptozotocin-induced diabetic rats and its regulation on muscular glycogenesis may play a role in the underlying mechanism. PMID:26902078

  8. Turbulence and intermittent transport at the boundary of magnetized plasmas

    DEFF Research Database (Denmark)

    Garcia, O.E.; Naulin, V.; Nielsen, A.H.;

    2005-01-01

    Numerical fluid simulations of interchange turbulence for geometry and parameters relevant to the boundary region of magnetically confined plasmas are shown to result in intermittent transport qualitatively similar to recent experimental measurements. The two-dimensional simulation domain features...... a forcing region with spatially localized sources of particles and heat outside which losses due to the motion along open magnetic-field lines dominate, corresponding to the edge region and the scrape-off layer, respectively. Turbulent states reveal intermittent eruptions of hot plasma from the edge region...

  9. Acute Intermittent Porphyria Associated with Respiratory Failure: A Multidisciplinary Approach

    Directory of Open Access Journals (Sweden)

    Mayra Gonçalves Menegueti

    2011-01-01

    Full Text Available Despite being challenging, delivery of effective nursing care to patients with acute intermittent porphyria is a matter of utmost importance. In this paper, the diversity of symptoms and the difficult diagnosis of this condition are emphasized, and details concerning the treatment of this disorder in the intensive care unit are presented. We believe that acute intermittent porphyria should be borne in mind during performance of differential diagnosis of neurological, psychiatric, and gastroenterological disorders on patients whose routine investigation tests are normal, especially when precipitating factors exist. Intensive care measures and a multidisciplinary team approach are essential.

  10. Acute intermittent porphyria associated with respiratory failure: a multidisciplinary approach.

    Science.gov (United States)

    Menegueti, Mayra Gonçalves; Gil Cezar, Alkmim-Teixeira; Casarini, Karin Aparecida; Muniz Cordeiro, Kátia Simone; Basile-Filho, Anibal; Martins-Filho, Olindo Assis; Auxiliadora-Martins, Maria

    2011-01-01

    Despite being challenging, delivery of effective nursing care to patients with acute intermittent porphyria is a matter of utmost importance. In this paper, the diversity of symptoms and the difficult diagnosis of this condition are emphasized, and details concerning the treatment of this disorder in the intensive care unit are presented. We believe that acute intermittent porphyria should be borne in mind during performance of differential diagnosis of neurological, psychiatric, and gastroenterological disorders on patients whose routine investigation tests are normal, especially when precipitating factors exist. Intensive care measures and a multidisciplinary team approach are essential. PMID:21687623

  11. Intermittency-friendly and high-efficiency cogeneration

    DEFF Research Database (Denmark)

    Blarke, Morten; Dotzauer, Erik

    2011-01-01

    -efficiency and widely applicable option in distributed cogeneration better supporting the co-existence between cogenerators and intermittent renewables in the energy system. The concept involves integrating an efficient high-temperature compression heat pump that uses only waste heat recovered from flue gases as low....... It is found that CHP-HP-FG-CS offers significant reductions in fuel consumption (−8.9%) and operational production costs (−11.4%). The plant’s fuel-to-energy efficiency increases from 88.9 to 95.5%, which is state-of-the-art. The plant’s intermittency-friendliness coefficient Rc improves only marginally due...

  12. Challenges to Cabin Humidity Removal Presented by Intermittent Condensing Conditions

    Science.gov (United States)

    vonJouanne, Roger G.; Williams, David E.

    2007-01-01

    On-orbit temperature and humidity control (THC) is more easily accomplished when the THC hardware is either consistently dry (i.e., no humidity control is occurring), or consistently wet. The system is especially challenged when intermittent wet/dry conditions occur. The first six years of on-orbit ISS operations have revealed specific concerns within the THC system, specifically in the condensing heat exchanger and the downstream air/water separator. Failed or degraded hardware has been returned to ground and investigated. This paper presents the investigation findings, and the recommended hardware and procedural revisions to prevent and recover from the effects of intermittent condensing conditions.

  13. Solar flare intermittency and the earth's temperature anomalies.

    Science.gov (United States)

    Scafetta, Nicola; West, Bruce J

    2003-06-20

    We argue that Earth's short-term temperature anomalies and the solar flare intermittency are linked. The analysis is based upon the study of the scaling of both the spreading and the entropy of the diffusion generated by the fluctuations of the temperature time series. The joint use of these two methods evidences the presence of a Lévy component in the temporal persistence of the temperature data sets that corresponds to the one that would be induced by the solar flare intermittency. The mean monthly temperature data sets cover the period from 1856 to 2002. PMID:12857233

  14. Acute Intermittent Porphyria Associated with Respiratory Failure: A Multidisciplinary Approach

    Science.gov (United States)

    Menegueti, Mayra Gonçalves; Gil Cezar, Alkmim-Teixeira; Casarini, Karin Aparecida; Muniz Cordeiro, Kátia Simone; Basile-Filho, Anibal; Martins-Filho, Olindo Assis; Auxiliadora-Martins, Maria

    2011-01-01

    Despite being challenging, delivery of effective nursing care to patients with acute intermittent porphyria is a matter of utmost importance. In this paper, the diversity of symptoms and the difficult diagnosis of this condition are emphasized, and details concerning the treatment of this disorder in the intensive care unit are presented. We believe that acute intermittent porphyria should be borne in mind during performance of differential diagnosis of neurological, psychiatric, and gastroenterological disorders on patients whose routine investigation tests are normal, especially when precipitating factors exist. Intensive care measures and a multidisciplinary team approach are essential. PMID:21687623

  15. Effects of Intermittent Fasting, Caloric Restriction, and Ramadan Intermittent Fasting on Cognitive Performance at Rest and During Exercise in Adults.

    Science.gov (United States)

    Cherif, Anissa; Roelands, Bart; Meeusen, Romain; Chamari, Karim

    2016-01-01

    The aim of this review was to highlight the potent effects of intermittent fasting on the cognitive performance of athletes at rest and during exercise. Exercise interacts with dietary factors and has a positive effect on brain functioning. Furthermore, physical activity and exercise can favorably influence brain plasticity. Mounting evidence indicates that exercise, in combination with diet, affects the management of energy metabolism and synaptic plasticity by affecting molecular mechanisms through brain-derived neurotrophic factor, an essential neurotrophin that acts at the interface of metabolism and plasticity. The literature has also shown that certain aspects of physical performance and mental health, such as coping and decision-making strategies, can be negatively affected by daylight fasting. However, there are several types of intermittent fasting. These include caloric restriction, which is distinct from fasting and allows subjects to drink water ad libitum while consuming a very low-calorie food intake. Another type is Ramadan intermittent fasting, which is a religious practice of Islam, where healthy adult Muslims do not eat or drink during daylight hours for 1 month. Other religious practices in Islam (Sunna) also encourage Muslims to practice intermittent fasting outside the month of Ramadan. Several cross-sectional and longitudinal studies have shown that intermittent fasting has crucial effects on physical and intellectual performance by affecting various aspects of bodily physiology and biochemistry that could be important for athletic success. Moreover, recent findings revealed that immunological variables are also involved in cognitive functioning and that intermittent fasting might impact the relationship between cytokine expression in the brain and cognitive deficits, including memory deficits. PMID:26438184

  16. INTERMITTENT CLONAZEPAM IN THE PREVENTION OF RECURRENT FEBRILE SEIZURES

    Directory of Open Access Journals (Sweden)

    Touran MAHMOUDIAN

    2010-10-01

    Full Text Available ObjectiveTo evaluate the efficacy and common side effects of intermittent clonazepam in febrile  seizures.Materials & MethodsThis study was an experimental trial designed to determine the efficacy of intermittent clonazepam in febrile seizures .Thirty patients with an age range of 6 months to 5 years (60% male, 40% female were studied. Children with a history of psychomotor delay, abnormal  neurological examination, a history of antiepileptic drug consumption, and afebrile seizures were excluded from the study. Patients received a single dose of prophylactic Clonazepam (0.05 mg/kg/ day on the first day of febrile illness and twice daily during the course of fever.An antipyretic medication (Acetaminophen was advised if fever exceeded 38oC. Patients were followed up for one year after the study inclusion date.ResultsThree patients were excluded from study since they didnot follow the tritment and three patients experienced afebrile seizures. Twenty four patients had 162 febrile episodes during the course of the study and all patients were seizure-free after 1 year.ConclusionClonazepam was 100% effective but lethargy and ataxia were common side effects in patients. Fortunately, their parents continued treatment because they had prior awareness of the  possible side effects of clonazepam. Clonazepam is efficacious as an intermittent therapy for febrile seizures if parents are informed of its side effects.Keywords: recurrent febrile seizures, clonazepam, intermittent prophylaxis

  17. Muscle Fatigue during Intermittent Exercise in Individuals with Mental Retardation

    Science.gov (United States)

    Zafeiridis, Andreas; Giagazoglou, Paraskevi; Dipla, Konstantina; Salonikidis, Konstantinos; Karra, Chrisanthi; Kellis, Eleftherios

    2010-01-01

    This study examined fatigue profile during intermittent exercise in 10 men with mild to moderate mental retardation (MR) and 10 men without mental retardation (C). They performed 4 x 30 s maximal knee extensions and flexions with 1-min rest on an isokinetic dynamometer. Peak torque of flexors (PTFL) and extensors (PTEX), total work (TW), and…

  18. Serum bilirubin kinetics in intermittent phototherapy of physiological jaundice.

    OpenAIRE

    Lau, S. P.; Fung, K P

    1984-01-01

    Thirty four term babies with physiological jaundice were subjected to continuous phototherapy and to two regimens of intermittent phototherapy. The difference in serum bilirubin kinetics between the three groups of treated babies was insignificant; a schedule of one in four hours of irradiation achieved the same treatment effect as continuous phototherapy.

  19. Intermittent Versus Continuous Phototherapy for Reducing Neonatal Hyperbilirubinemia

    Directory of Open Access Journals (Sweden)

    Nikoo Niknafs

    2008-09-01

    Full Text Available Objective: Clinical studies comparing intermittent versus continuous phototherapy for reducing neonatal hyperbilirubinemia have produced conflicting results. This study was conducted to compare the efficacy of intermittent with continuous phototherapy. Methods: This study was performed on 114 neonates with indirect hyperbilirubinemia. Inclusion criteria were body weight above 2000 grams, absence of other concomitant diseases, and hyperbilirubinemia neither requiring intensive phototherapy nor exceeding the range of exchange transfusion. The neonates were randomly divided into two groups. Continuous phototherapy group received phototherapy on and off for 2 hours and half an hour respectively and the intermittent phototherapy group on and off for one hour. The phototherapy units were identical and serum total bilirubin levels were measured every 12 hours after starting phototherapy. Findings: Two groups were matched regarding weight and risk factors such as ABO and Rh incompatibility. The difference of total serum bilirubin levels between two groups was insignificant at the start of phototherapy and also after 12, 24, 36 and 48 hours (P>0.2.Conclusion: Intermittent phototherapy defined as one hour on and one hour off is as effective as continuous phototherapy defined as 2 hours on and half an hour off, in reducing total serum bilirubin level in full term babies.

  20. Intermittent versus continuous administration of growth hormone treatment.

    OpenAIRE

    Hakeem, V; Hindmarsh, P. C.; Brook, C G

    1993-01-01

    Growth hormone treatment given by daily injection was compared with growth hormone given for three weeks of every four. All children had received recombinant human growth hormone for two years before randomisation. Growth velocity decreased in both groups in years one and two of the study but the effect was significantly greater in the group receiving intermittent growth hormone.

  1. Quasi-one-dimensional intermittent flux behavior in superconducting films

    DEFF Research Database (Denmark)

    Qviller, A. J.; Yurchenko, V. V.; Galperin, Y. M.;

    2012-01-01

    Intermittent filamentary dynamics of the vortex matter in superconductors is found in films of YBa2Cu3O7-δ deposited on tilted substrates. Deposition of this material on such substrates creates parallel channels of easy flux penetration when a magnetic field is applied perpendicular to the film. ...

  2. Two-scale analysis of intermittency in fully developed turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Badii, R.; Talkner, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    A self-affinity test for turbulent time series is applied to experimental data for the estimation of intermittency exponents. The method employs exact relations satisfied by joint expectations of observables computed across two different length scales. One of these constitutes a verification tool for the existence and the extent of the inertial range. (author) 2 figs., 13 refs.

  3. Mathematical analysis of intermittent gas injection model in oil production

    Science.gov (United States)

    Tasmi, Silvya, D. R.; Pudjo, S.; Leksono, M.; Edy, S.

    2016-02-01

    Intermittent gas injection is a method to help oil production process. Gas is injected through choke in surface and then gas into tubing. Gas forms three areas in tubing: gas column area, film area and slug area. Gas column is used to propel slug area until surface. A mathematical model of intermittent gas injection is developed in gas column area, film area and slug area. Model is expanding based on mass and momentum conservation. Using assume film thickness constant in tubing, model has been developed by Tasmi et. al. [14]. Model consists of 10 ordinary differential equations. In this paper, assumption of pressure in gas column is uniform. Model consist of 9 ordinary differential equations. Connection of several variables can be obtained from this model. Therefore, dynamics of all variables that affect to intermittent gas lift process can be seen from four equations. To study the behavior of variables can be analyzed numerically and mathematically. In this paper, simple mathematically analysis approach is used to study behavior of the variables. Variables that affect to intermittent gas injection are pressure in upstream valve and in gas column. Pressure in upstream valve will decrease when gas mass in valve greater than gas mass in choke. Dynamic of the pressure in the gas column will decrease and increase depending on pressure in upstream valve.

  4. Intermittent breeding as a cost of site fidelity

    NARCIS (Netherlands)

    Bruinzeel, Louis

    2007-01-01

    Intermittent breeding (skipping a breeding season) can be the result of an adaptive decision by a focal individual, trading current reproductive success in favour of future reproductive success (residual reproductive value hypothesis). In contrast, an individual can also be forced by conspecifics to

  5. Intermittency and multifractional Brownian character of geomagnetic time series

    Directory of Open Access Journals (Sweden)

    G. Consolini

    2013-07-01

    Full Text Available The Earth's magnetosphere exhibits a complex behavior in response to the solar wind conditions. This behavior, which is described in terms of mutifractional Brownian motions, could be the consequence of the occurrence of dynamical phase transitions. On the other hand, it has been shown that the dynamics of the geomagnetic signals is also characterized by intermittency at the smallest temporal scales. Here, we focus on the existence of a possible relationship in the geomagnetic time series between the multifractional Brownian motion character and the occurrence of intermittency. In detail, we investigate the multifractional nature of two long time series of the horizontal intensity of the Earth's magnetic field as measured at L'Aquila Geomagnetic Observatory during two years (2001 and 2008, which correspond to different conditions of solar activity. We propose a possible double origin of the intermittent character of the small-scale magnetic field fluctuations, which is related to both the multifractional nature of the geomagnetic field and the intermittent character of the disturbance level. Our results suggest a more complex nature of the geomagnetic response to solar wind changes than previously thought.

  6. Bochdalek Hernia As A Cause Of Intermittent AV Block

    OpenAIRE

    Etsadashvili, Kakhaber; Rashid, Haroon Mohammed; Jalabadze, Khatuna; Melia, Anzor

    2011-01-01

    Congenital diaphragmatic hernia is very rare cause of AV block. We report such a patient with sick sinus node syndrome and previous AAIR pacemaker implantation, in which intermittent AV block was diagnosed by 24-hours ECG monitoring and upgrade of pacing system to DDDR was suggested.

  7. Optimizing supervised exercise therapy for patients with intermittent claudication

    NARCIS (Netherlands)

    Nicolaï, Saskia P A; Hendriks, Erik J M; Prins, Martin H; Teijink, Joep A W; van Asselt, Thea

    2010-01-01

    BACKGROUND: The first-line intervention for intermittent claudication is usually supervised exercise therapy (SET). The literature describes a range of exercise programs varying in setting, duration, and content. The purpose of the present study was to examine the exercise protocols offered and to i

  8. Radial evolution of intermittency of density fluctuations in the fast solar wind

    CERN Document Server

    Bruno, R; Primavera, L; Pietropaolo, E; D'Amicis, R; Sorriso-Valvo, L; Carbone, V; Malara, F; Veltri, P

    2014-01-01

    We study the radial evolution of intermittency of density fluctuations in the fast solar wind. The study is performed analyzing the plasma density measurements provided by Helios 2 in the inner heliosphere between $0.3$ and $0.9$ AU. The analysis is carried out by means of a complete set of diagnostic tools, including the flatness factor at different time scales to estimate intermittency, the Kolmogorov-Smirnov test to estimate the degree of intermittency, and the Fourier transform to estimate the power spectral densities of these fluctuations. Density fluctuations within fast wind are rather intermittent and their level of intermittency, together with the amplitude of intermittent events, decreases with distance from the Sun, at odds with intermittency of both magnetic field and all the other plasma parameters. Furthermore, the intermittent events are strongly correlated, exhibiting temporal clustering. This indicates that the mechanism underlying their generation departs from a time-varying Poisson process....

  9. Study of drying of small diameter Larch lumbers with intermittent heating

    Institute of Scientific and Technical Information of China (English)

    GUO Ming-hui; ZHAO Xi-ping

    2006-01-01

    Intermittent heating for drying of small diameter Larch lumbers is investigated experimentally. The lumbers were dried using an experimental drying schedule. Moisture content (MC) of the lumber was continuously recorded and final drying defects were examined. The drying curves showed that the drying rate was a constant in the early stage of intermittent heating drying and decreased evidently when the MC was about 18% ( intermittent 2h) and 20% (intermittent 6h). The drying quality reached the second (intermittent 2h) and first grade (intermittent 6h) of the Chinese National Standard. The visual drying defects, especially the check extent along grains were reduced with intermittent heating. When the intermittent time increased, the effect was more obvious.

  10. Characterizing spatial and temporal patterns of intermittent rivers

    Science.gov (United States)

    de Vries, Stefan B.; Hoeve, Jasper; Sauquet, Eric; Leigh, Catherine; Bonada, Núria; Fike, Kimberly; Dahm, Clifford; Booij, Martijn J.; Datry, Thibault

    2015-04-01

    Intermittent rivers (IRs) support high biodiversity due to their dynamic alternations between terrestrial and aquatic phases. They represent a large proportion of the river network. However the current knowledge on these ecosystems is limited. The international research project "Intermittent River Biodiversity Analysis and Synthesis" (IRBAS, www.irbas.fr) aims to collect and analyze data on IR biodiversity from France, Spain, North America and Australia. These activities ultimately should help in identifying relationships between flow regime components and ecological responses. The IRBAS project will provide guidelines for policy-makers and resource managers for effective water and habitat management, restoration and preservation. This work examines one of the aspects in the IRBAS project: studying the large-scale spatial distribution of IRs as well as the year-to-year variability of zero-flow events. IRs were described by two variables: the frequency of periods without flow (FREQ) per time period (months or years) and the total number of zero-flow days (DUR) in a specified time window (month or year). Daily discharge data from more than 1700 gauging stations with no significant human influence on flow were collected from France, Spain, Australia and conterminous United States. A minimum length of 30 years of data starting from 1970 was required with less than 5% of missing data. Climate data for France and Australia were also collected. A classification of perennial versus intermittent rivers was defined, with 455 stations out of the 1684 considered "intermittent", i.e. the gauging station records had, on average, at least 5 zero-flow days per year. The analysis of the subset of IRs showed that: - Greater than 50% of the IRs in the database is located in Australia, where only 35% of the stations are considered perennial. In Spain the proportion of IRs reaches 25%. The proportion of intermittent rivers in France (7%) is certainly underestimated as a consequence of

  11. Randomized double-blind placebo-controlled crossover study of caffeine in patients with intermittent claudication

    DEFF Research Database (Denmark)

    Momsen, A H; Jensen, M B; Norager, C B;

    2010-01-01

    Intermittent claudication is a disabling symptom of peripheral arterial disease for which few medical treatments are available. This study investigated the effect of caffeine on physical capacity in patients with intermittent claudication.......Intermittent claudication is a disabling symptom of peripheral arterial disease for which few medical treatments are available. This study investigated the effect of caffeine on physical capacity in patients with intermittent claudication....

  12. The influence of continuous and intermittent traffic noise on sleep

    Science.gov (United States)

    Eberhardt, J. L.; Stråle, L.-O.; Berlin, M. H.

    1987-08-01

    The effects of road traffic noise on sleep were studied in the laboratory using nine young male adults (aged 20-26). The subjects were exposed to noise with different temporal characteristics: (i) continuous traffic noise of 36 dB(A) or 45 dB(A), (ii) intermittent noise of 50 truck passages with L pmax = 45 dB(A) ( L eq = 29 dB(A)) or L pmax = 55 dB(A) ( L eq = 36 dB(A)), and (iii) a combination of continuous (45 dB(A)) and intermittent ( L pmax = 55 dB(A)) traffic noise. For one noise condition (intermittent 55 dB(A)) the effect of the use of ear plugs was also studied. The intermittent noise of L pmax = 45 dB(A) caused transitions towards lighter sleep, whereas 55 dB(A) was needed to induce awakening effects. It could be shown that the probability for arousal reactions depends on the emergence of the noise peaks from the background, rather than the absolute noise peak level. Continuous traffic noise of 45 dB(A) caused REM sleep deficits, while intermittent traffic noise of L pmax = 45 dB(A) caused stage III+IV deficits. The night with ear plugs was virtually undisturbed. After nights with REM sleep deficits the subjective sleep quality was rated lower and mood was influenced adversely. For the types of exposure used in the present investigation L eq alone is not an adequate descriptor of the noise dose, relating to the sleep disturbances observed. From the present experiment, together with other existing data, it might be concluded that the WHO recommendation of L eq = 35 dB(A) is adequate, but should be supplemented with a maximum noise level, as expressed for example in L pmax or LI, that should not be exceeded.

  13. Demographics and frequency of the intermittently upturned omentum at CT

    Energy Technology Data Exchange (ETDEWEB)

    Penn, Alex; Wang, Wilbur; Wang, Zhen Jane; Yee, Judy; Webb, Emily M.; Yeh, Benjamin M., E-mail: ben.yeh@ucsf.edu

    2013-11-01

    Objectives: To describe the demographics and frequency of the intermittently upturned omentum at CT. Methods: We retrospectively reviewed abdominal CT scans of 336 consecutive patients (189 men and 147 women) who were imaged between June 1 and June 17, 2010 and who had prior comparison scans. Readers recorded the presence or absence of an intermittently upturned omentum, defined as a thick rind of fat interposed between the liver and the anterior abdominal wall seen on one but not the other scan. At chart review, we recorded patient demographics and other clinical characteristics (prior surgical history, presence of cirrhosis). Results: An intermittently upturned omentum was found in 10 of 336 (3.0%) patients. An intermittently upturned omentum was seen more commonly in men than in women (9 of 189 men, or 4.8% versus 1 of 147 women, or 0.7%, p = 0.047) and in cirrhotics (4 of 37 cirrhotics, or 10.8% versus 6 of 299 non-cirrhotics, or 2.0%, p = 0.023). In a sub-analysis of patients without prior abdominal surgery, this finding was again seen more commonly in men than women (7 of 163 men, or 4.3% versus 0 of 134 women, or 0%, p = 0.018) and in cirrhotics (3 of 33 cirrhotics, or 9.1% versus 4 of 264 non-cirrhotics, or 1.5%, p = 0.032). Conclusions: An intermittently upturned omentum is not uncommon and is more frequently seen in men and in patients with cirrhosis who may have a larger anterior hepatic space.

  14. Observation of intermittency in gene expression on cDNA microarrays

    CERN Document Server

    Peterson, L E

    2002-01-01

    We used scaled factorial moments to search for intermittency in the log expression ratios (LERs) for thousands of genes spotted on cDNA microarrays (gene chips). Results indicate varying levels of intermittency in gene expression. The observation of intermittency in the data analyzed provides a complimentary handle on moderately expressed genes, generally not tackled by conventional techniques.

  15. A Carrier Signal Approach for Intermittent Fault Detection and Health Monitoring for Electronics Interconnections System

    Directory of Open Access Journals (Sweden)

    Syed Wakil Ahmad

    2015-12-01

    Full Text Available Intermittent faults are completely missed out by traditional monitoring and detection techniques due to non-stationary nature of signals. These are the incipient events of a precursor of permanent faults to come. Intermittent faults in electrical interconnection are short duration transients which could be detected by some specific techniques but these do not provide enough information to understand the root cause of it. Due to random and non-predictable nature, the intermittent faults are the most frustrating, elusive, and expensive faults to detect in interconnection system. The novel approach of the author injects a fixed frequency sinusoidal signal into electronics interconnection system that modulates intermittent fault if persist. Intermittent faults and other channel effects are computed from received signal by demodulation and spectrum analysis. This paper describes technology for intermittent fault detection, and classification of intermittent fault, and channel characterization. The paper also reports the functionally tests of computational system of the proposed methods. This algorithm has been tested using experimental setup. It generate an intermittent signal by external vibration stress on connector and intermittency is detected by acquiring and processing propagating signal. The results demonstrate to detect and classify intermittent interconnection and noise variations due to intermittency. Monitoring the channel in-situ with low amplitude, and narrow band signal over electronics interconnection between a transmitter and a receiver provides the most effective tool for continuously watching the wire system for the random, unpredictable intermittent faults, the precursor of failure.

  16. Ring intermittency near the boundary of the synchronous time scales of chaotic oscillators

    OpenAIRE

    Zhuravlev, Maxim O.; Koronovskii, Alexey A.; Moskalenko, Olga I.; Ovchinnikov, Alexey A.; Hramov, Alexander E.

    2013-01-01

    In this paper we study both experimentally and numerically the intermittent behavior taking place near the boundary of the synchronous time scales of chaotic oscillators being in the regime of time scale synchronization. We have shown that the observed type of the intermittent behavior should be classified as the ring intermittency.

  17. Ring intermittency near the boundary of the synchronous time scales of chaotic oscillators.

    Science.gov (United States)

    Zhuravlev, Maxim O; Koronovskii, Alexey A; Moskalenko, Olga I; Ovchinnikov, Alexey A; Hramov, Alexander E

    2011-02-01

    In this Brief Report we study both experimentally and numerically the intermittent behavior taking place near the boundary of the synchronous time scales of chaotic oscillators being in the regime of time scale synchronization. We have shown that the observed type of the intermittent behavior should be classified as the ring intermittency.

  18. Metallothionein as a compensatory component prevents intermittent hypoxia-induced cardiomyopathy in mice

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Xia; Zhou, Shanshan [The First Hospital of Jilin University, Changchun, 130021 (China); KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Zheng, Yang, E-mail: zhengyang@jlu.edu.cn [The First Hospital of Jilin University, Changchun, 130021 (China); Tan, Yi [KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Chinese–American Research Institute for Diabetic Complications, Wenzhou Medical College School of Pharmacy, Wenzhou, 325035 (China); Kong, Maiying [Department of Bioinformatics and Biostatistics, School of Public Health and Information Sciences, University of Louisville, Louisville, KY 40202 (United States); Wang, Bo [KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Department of Pathology, Inner Mongolia Forestry General Hospital, Yakeshi, 022150 (China); Feng, Wenke [Department of Medicine, School of Medicine, University of Louisville, Louisville, 40202 (United States); Epstein, Paul N. [KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Cai, Jun, E-mail: j0cai002@louisville.edu [KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Cai, Lu [KCHRI at the Department of Pediatrics, School of Medicine, University of Louisville, Louisville, 40202 (United States); Chinese–American Research Institute for Diabetic Complications, Wenzhou Medical College School of Pharmacy, Wenzhou, 325035 (China); Department of Medicine, School of Medicine, University of Louisville, Louisville, 40202 (United States)

    2014-05-15

    Obstructive sleep apnea (OSA) causes chronic intermittent hypoxia (IH) to induce cardiovascular disease, which may be related to oxidative damage. Metallothionein (MT) has been extensively proved to be an endogenous and highly inducible antioxidant protein expressed in the heart. Therefore, we tested the hypotheses that oxidative stress plays a critical role in OSA induced cardiac damage and MT protects the heart from OSA-induced cardiomyopathy. To mimic hypoxia/reoxygenation events that occur in adult OSA patients, mice were exposed to IH for 3 days to 8 weeks. The IH paradigm consisted of alternating cycles of 20.9% O{sub 2}/8% O{sub 2} F{sub I}O{sub 2} (30 episodes per hour) with 20 s at the nadir F{sub I}O{sub 2} for 12 h a day during daylight. IH significantly increased the ratio of heart weight to tibia length at 4 weeks with a decrease in cardiac function from 4 to 8 weeks. Cardiac oxidative damage and fibrosis were observed after 4 and 8 weeks of IH exposures. Endogenous MT expression was up-regulated in response to 3-day IH, but significantly decreased at 4 and 8 weeks of IH. In support of MT as a major compensatory component, mice with cardiac overexpression of MT gene and mice with global MT gene deletion were completely resistant, and highly sensitive, respectively, to chronic IH induced cardiac effects. These findings suggest that chronic IH induces cardiomyopathy characterized by oxidative stress-mediated cardiac damage and the antioxidant MT protects the heart from such pathological and functional changes. - Highlights: • The effect of intermittent hypoxia (IH) on cardiac metallothionein (MT) • Cardiac MT expression was up-regulated in response to 3-day IH. • Exposure to 4- or 8-week IH downregulated cardiac MT expression. • Overexpression of cardiac MT protects from IH-induced cardiac damage. • Global deletion of MT gene made the heart more sensitive to IH damage.

  19. [Chronicity, chronicization, systematization of delusions].

    Science.gov (United States)

    Trapet, P; Fernandez, C; Galtier, M C; Gisselmann, A

    1984-05-01

    Chronicity in psychopathology is indicative of a term, a decay. Chronicization only leads the way to this term. Here, chronicization is taken literally as an inscription in the time course of delusions. The mechanism of systematization seems to be a central mark in the approach to chronic delusions. It is not an alienation or an irreversible closing but an attempted accommodation with reality in the life of psychotic subjects, irrespective of the delusional structure. The role of therapy and drug treatment as a follow-up may in that case assume another meaning.

  20. Synthesis of Intermittent-Motion Linkages with Slight Difference in Length Between Links

    Institute of Scientific and Technical Information of China (English)

    CHEN Xin-bo; YU Zhen

    2006-01-01

    The design of intermittent-motion linkages using traditional methods iS usually complicated.In this paper,(1)a new method for realizing intermittent motion,using linkages with a slight difference in length between links,is studied;(2)some new types of intermittent-motion linkages and their software for visual analysis and design are developed;and(3)influences of some design parameters on intermittent.motion characteristics are clarifled.Results confirmed that the theory and the software are useful,making the synthesis of intermittent-motion linkages clear and easy.

  1. Intermittency in an optomechanical cavity near a subcritical Hopf bifurcation

    Science.gov (United States)

    Suchoi, Oren; Ella, Lior; Shtempluk, Oleg; Buks, Eyal

    2014-09-01

    We experimentally study an optomechanical cavity consisting of an oscillating mechanical resonator embedded in a superconducting microwave transmission line cavity. Tunable optomechanical coupling between the mechanical resonator and the microwave cavity is introduced by positioning a niobium-coated single-mode optical fiber above the mechanical resonator. The capacitance between the mechanical resonator and the coated fiber gives rise to optomechanical coupling, which can be controlled by varying the fiber-resonator distance. We study radiation-pressure-induced self-excited oscillation as a function of microwave driving parameters (frequency and power). Intermittency between limit-cycle and steady-state behaviors is observed with blue-detuned driving frequency. The experimental results are accounted for by a model that takes into account the Duffing-like nonlinearity of the microwave cavity. A stability analysis reveals a subcritical Hopf bifurcation near the region where intermittency is observed.

  2. Synchronization of intermittent behavior in ensembles of multistable dynamical systems.

    Science.gov (United States)

    Sevilla-Escoboza, R; Buldú, J M; Pisarchik, A N; Boccaletti, S; Gutiérrez, R

    2015-03-01

    We propose a methodology to analyze synchronization in an ensemble of diffusively coupled multistable systems. First, we study how two bidirectionally coupled multistable oscillators synchronize and demonstrate the high complexity of the basins of attraction of coexisting synchronous states. Then, we propose the use of the master stability function (MSF) for multistable systems to describe synchronizability, even during intermittent behavior, of a network of multistable oscillators, regardless of both the number of coupled oscillators and the interaction structure. In particular, we show that a network of multistable elements is synchronizable for a given range of topology spectra and coupling strengths, irrespective of specific attractor dynamics to which different oscillators are locked, and even in the presence of intermittency. Finally, we experimentally demonstrate the feasibility and robustness of the MSF approach with a network of multistable electronic circuits.

  3. On the intermittent character of interplanetary magnetic field fluctuations

    CERN Document Server

    Bruno, Roberto; Chapman, Sandra; Hnat, Bogdan; Noullez, Alain; Sorriso-Valvo, Luca; 10.1063/1.2711429

    2009-01-01

    Interplanetary magnetic field magnitude fluctuations are notoriously more intermittent than velocity fluctuations in both fast and slow wind. This behaviour has been interpreted in terms of the anomalous scaling observed in passive scalars in fully developed hydrodynamic turbulence. In this paper, the strong intermittent nature of the interplanetary magnetic field is briefly discussed comparing results performed during different phases of the solar cycle. The scaling properties of the interplanetary magnetic field magnitude show solar cycle variation that can be distinguished in the scaling exponents revealed by structure functions. The scaling exponents observed around solar maximum coincide, within the errors, to those measured for passive scalars in hydrodynamic turbulence. However, it is also found that the values are not universal in the sense that the solar cycle variation may be reflected in dependence on the structure of the velocity field.

  4. Intermittency in fractal Fourier hydrodynamics: Lessons from the Burgers equation.

    Science.gov (United States)

    Buzzicotti, Michele; Biferale, Luca; Frisch, Uriel; Ray, Samriddhi Sankar

    2016-03-01

    We present theoretical and numerical results for the one-dimensional stochastically forced Burgers equation decimated on a fractal Fourier set of dimension D. We investigate the robustness of the energy transfer mechanism and of the small-scale statistical fluctuations by changing D. We find that a very small percentage of mode-reduction (D ≲ 1) is enough to destroy most of the characteristics of the original nondecimated equation. In particular, we observe a suppression of intermittent fluctuations for D < 1 and a quasisingular transition from the fully intermittent (D=1) to the nonintermittent case for D ≲ 1. Our results indicate that the existence of strong localized structures (shocks) in the one-dimensional Burgers equation is the result of highly entangled correlations amongst all Fourier modes. PMID:27078449

  5. Tissue-specific splicing mutation in acute intermittent porphyria

    International Nuclear Information System (INIS)

    An inherited deficiency of porphobilinogen deaminase in humans is responsible for the autosomal dominant disease acute intermittent porphyria. Different classes of mutations have been described at the protein level suggesting that this is a heterogeneous disease. It was previously demonstrated that porphobilinogen deaminase is encoded by two distinct mRNA species expressed in a tissue-specific manner. Analysis of the genomic sequences indicated that these two mRNAs are transcribed from two promoters and only differ in their first exon. The first mutation identified in the human porphobilinogen deaminase gene is a single-base substitution (G → A) in the canonical 5' splice donor site of intron 1. This mutation leads to a particular subtype of acute intermittent porphyria characterized by the restriction of the enzymatic defect to nonerythropoietic tissues. Hybridization analysis using olignonucleotide probes after in vitro amplification of genomic DNA offers another possibility of detecting asymptomatic carriers of the mutation in affected families

  6. Intermittency and correlations in hadronic $Z^0$ decays

    CERN Document Server

    Abbiendi, G; Alexander, Gideon; Allison, J; Altekamp, N; Anderson, K J; Anderson, S; Arcelli, S; Asai, S; Ashby, S F; Axen, D A; Azuelos, Georges; Ball, A H; Barberio, E; Barlow, R J; Batley, J Richard; Baumann, S; Bechtluft, J; Behnke, T; Bell, K W; Bella, G; Bellerive, A; Bentvelsen, Stanislaus Cornelius Maria; Bethke, Siegfried; Betts, S; Biebel, O; Biguzzi, A; Blobel, Volker; Bloodworth, Ian J; Bock, P; Böhme, J; Bonacorsi, D; Boutemeur, M; Braibant, S; Bright-Thomas, P G; Brigliadori, L; Brown, R M; Burckhart, Helfried J; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Chrisman, D; Ciocca, C; Clarke, P E L; Clay, E; Cohen, I; Conboy, J E; Cooke, O C; Couyoumtzelis, C; Coxe, R L; Cuffiani, M; Dado, S; Dallavalle, G M; Davis, R; De Jong, S; de Roeck, A; Dervan, P J; Desch, Klaus; Dienes, B; Dixit, M S; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Estabrooks, P G; Etzion, E; Fabbri, Franco Luigi; Fanfani, A; Fanti, M; Faust, A A; Fiedler, F; Fierro, M; Fleck, I; Folman, R; Frey, A; Fürtjes, A; Futyan, D I; Gagnon, P; Gary, J W; Gascon, J; Gascon-Shotkin, S M; Gaycken, G; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Gibson, V; Gibson, W R; Gingrich, D M; Glenzinski, D A; Goldberg, J; Gorn, W; Grandi, C; Graham, K; Gross, E; Grunhaus, Jacob; Gruwé, M; Hanson, G G; Hansroul, M; Hapke, M; Harder, K; Harel, A; Hargrove, C K; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Herndon, M; Herten, G; Heuer, R D; Hildreth, M D; Hill, J C; Hobson, P R; Hoch, M; Höcker, Andreas; Hoffman, K; Homer, R James; Honma, A K; Horváth, D; Hossain, K R; Howard, R; Hüntemeyer, P; Igo-Kemenes, P; Imrie, D C; Ishii, K; Jacob, F R; Jawahery, A; Jeremie, H; Jimack, Martin Paul; Jones, C R; Jovanovic, P; Junk, T R; Kanzaki, J I; Karlen, D A; Kartvelishvili, V G; Kawagoe, K; Kawamoto, T; Kayal, P I; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Kim, D H; Klier, A; Kobayashi, T; Kobel, M; Kokott, T P; Kolrep, M; Komamiya, S; Kowalewski, R V; Kress, T; Krieger, P; Von Krogh, J; Kühl, T; Kyberd, P; Lafferty, G D; Landsman, Hagar Yaël; Lanske, D; Lauber, J; Lautenschlager, S R; Lawson, I; Layter, J G; Lazic, D; Lee, A M; Lellouch, Daniel; Letts, J; Levinson, L; Liebisch, R; List, B; Littlewood, C; Lloyd, A W; Lloyd, S L; Loebinger, F K; Long, G D; Losty, Michael J; Lü, J; Ludwig, J; Liu, D; Macchiolo, A; MacPherson, A L; Mader, W F; Mannelli, M; Marcellini, S; Markopoulos, C; Martin, A J; Martin, J P; Martínez, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J A; McKigney, E A; McMahon, T J; McPherson, R A; Meijers, F; Menke, S; Merritt, F S; Mes, H; Meyer, J; Michelini, Aldo; Mihara, S; Mikenberg, G; Miller, D J; Mir, R; Mohr, W; Montanari, A; Mori, T; Nagai, K; Nakamura, I; Neal, H A; Nisius, R; O'Neale, S W; Oakham, F G; Odorici, F; Ögren, H O; Oreglia, M J; Orito, S; Pálinkás, J; Pásztor, G; Pater, J R; Patrick, G N; Patt, J; Pérez-Ochoa, R; Petzold, S; Pfeifenschneider, P; Pilcher, J E; Pinfold, James L; Plane, D E; Poffenberger, P R; Poli, B; Polok, J; Przybycien, M B; Rembser, C; Rick, Hartmut; Robertson, S; Robins, S A; Rodning, N L; Roney, J M; Rosati, S; Roscoe, K; Rossi, A M; Rozen, Y; Runge, K; Runólfsson, O; Rust, D R; Sachs, K; Saeki, T; Sahr, O; Sang, W M; Sarkisyan-Grinbaum, E; Sbarra, C; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schieck, J; Schmitt, S; Schöning, A; Schröder, M; Schumacher, M; Schwick, C; Scott, W G; Seuster, R; Shears, T G; Shen, B C; Shepherd-Themistocleous, C H; Sherwood, P; Siroli, G P; Sittler, A; Skuja, A; Smith, A M; Snow, G A; Sobie, Randall J; Söldner-Rembold, S; Spagnolo, S; Sproston, M; Stahl, A; Stephens, K; Steuerer, J; Stoll, K; Strom, D; Ströhmer, R; Surrow, B; Talbot, S D; Taras, P; Tarem, S; Teuscher, R; Thiergen, M; Thomas, J; Thomson, M A; Torrence, E; Towers, S; Trigger, I; Trócsányi, Z L; Tsur, E; Turcot, A S; Turner-Watson, M F; Ueda, I; Van Kooten, R; Vannerem, P; Verzocchi, M; Voss, H; Wäckerle, F; Wagner, A; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wermes, N; White, J S; Wilson, G W; Wilson, J A; Wyatt, T R; Yamashita, S; Yekutieli, G; Zacek, V; Zer-Zion, D

    1999-01-01

    A multidimensional study of local multiplicity fluctuations and multiparticle correlations of hadrons produced in Z decays is performed. The study is based on the data sample of more than 4 million events recorded with the OPAL detector at LEP. The fluctuations and correlations are analysed in terms of the normalized scaled factorial moments and cumulants up to the fifth order. The moments are observed to have intermittency-like behaviour, which is found to be more pronounced with increasing dimension. The large data sample allows for the first time a study of the factorial cumulants in e+e- annihilation. The analysis of the cumulants shows the existence of genuine multiparticle correlations with a strong intermittency rise up to higher orders. These correlations are found to be stronger in higher dimensions. The decomposition of the factorial moments into lower-order correlations that the dynamical fluctuations have important contributions from genuine many-particle correlations. The Monte Carlo models JETSE...

  7. Intermittency and local heating in the solar wind.

    Science.gov (United States)

    Osman, K T; Matthaeus, W H; Wan, M; Rappazzo, A F

    2012-06-29

    Evidence for nonuniform heating in the solar wind plasma near current sheets dynamically generated by magnetohydrodynamic (MHD) turbulence is obtained using measurements from the ACE spacecraft. These coherent structures only constitute 19% of the data, but contribute 50% of the total plasma internal energy. Intermittent heating manifests as elevations in proton temperature near current sheets, resulting in regional heating and temperature enhancements extending over several hours. The number density of non-Gaussian structures is found to be proportional to the mean proton temperature and solar wind speed. These results suggest magnetofluid turbulence drives intermittent dissipation through a hierarchy of coherent structures, which collectively could be a significant source of coronal and solar wind heating.

  8. Spinal Plasticity following Intermittent Hypoxia: Implications for Spinal Injury

    OpenAIRE

    Dale-Nagle, Erica A.; Hoffman, Michael S.; MacFarlane, Peter M.; Satriotomo, Irawan; Lovett-Barr, Mary Rachael; Vinit, Stéphane; Mitchell, Gordon S.

    2010-01-01

    Plasticity is a fundamental property of the neural system controlling breathing. One frequently studied model of respiratory plasticity is long-term facilitation of phrenic motor output (pLTF) following acute intermittent hypoxia (AIH). pLTF arises from spinal plasticity, increasing respiratory motor output through a mechanism that requires new synthesis of brain derived neurotrophic factor (BDNF), activation of its high affinity receptor, tropomyosin-related kinase B (TrkB) and extracellular...

  9. Low Dose Intermittent Isotretinoin Therapy in Moderate Acne Vulgaris

    OpenAIRE

    Belçın İzol; Emel Bülbül Başkan; Zübeyde Başar; Şükran Tunalı; Hayriye Sarıcaoğlu

    2012-01-01

    Objective: In this study, we aimed to investigate the efficiency and side effects of intermittent low dose isotretinoin therapy in moderate acne. Materials and Methods: Patients followed up at our acne outpatient clinic between September 2007 and April 2009 were evaluated. Those treated with 20 mg/day isotretinoin three times a week were included in the study. Relevant data were recorded from patient files. We recorded the age and weight of the cases, duration of acne, previous treatments, ac...

  10. Intermittent ion trajectories and focusing in spherical inertial electromagnetic confinement

    International Nuclear Information System (INIS)

    Performance of spherical magnetic electrostatic confinement fusion is analyzed. Magnetic field lines in spherical cusps provide a chaotic scattering system that improves the ion focusing due to synergetic effect of intermittent ion trajectories. Confined ions are bounced within electrostatic well reflecting from magnetic barriers shaped by convex field lines. The concept offers a means of enhancing ion reactivity provided by caustic formation that are resulted from an intersection of ion orbits within confinement volume. Parameters of the experimental device are estimated. (author)

  11. Intermittent control models of human standing: similarities and differences

    OpenAIRE

    Gawthrop, Peter; Loram, Ian; Gollee, Henrik; Lakie, Martin

    2014-01-01

    Two architectures of intermittent control are compared and contrasted in the context of the single inverted pendulum model often used for describing standing in humans. The architectures are similar insofar as they use periods of open-loop control punctuated by switching events when crossing a switching surface to keep the system state trajectories close to trajectories leading to equilibrium. The architectures differ in two significant ways. Firstly, in one case, the open-loop control trajec...

  12. Functions of intermittent locomotion in mustached tamarins ( Saguinus mystax)

    OpenAIRE

    Stojan-Dolar, Mojca; Heymann, Eckhard W.

    2015-01-01

    Many animals interrupt their moving with brief pauses, which appear to serve several different functions. We examined the function of such intermittent locomotion in wild living mustached tamarins (Saguinus mystax), small arboreal New World primates that form mixed-species groups with saddleback tamarins (Saguinus fuscicollis). We investigated how different environmental and social factors affect pausing during locomotion and used these data to infer the function of this behavior. As measures...

  13. Intermittent Jolts of Galactic UV Radiation: Mutagenetic Effects

    OpenAIRE

    Scalo, John M.; Wheeler, J. Craig; Williams, Peter

    2001-01-01

    We estimate the frequency of intermittent hypermutation events and disruptions of planetary/satellite photochemistry due to ultraviolet radiation from core collapse supernova explosions. Calculations are presented for planetary systems in the local Milky Way, including the important moderating effects of vertical Galactic structure and UV absorption by interstellar dust. The events are particularly frequent for satellites of giant gas planets at \\gtrsim 5-10 AU distance from solar-type parent...

  14. Epidemiological, clinical anf pathogenetic studies of acute intermittent porphyria

    OpenAIRE

    Bylesjö, Ingemar

    2008-01-01

    Porphyrias are inherited metabolic disorders characterised by an impairment of heme biosynthesis. Acute intermittent porphyria (AIP) is the most common of the acute porphyrias in Sweden. Acute attacks of AIP are characterised by neuro-psychiatric symptoms, including epileptic seizures. Environmental and acquired factors are related to the induction of symptoms. Acute attacks of AIP are treated with high doses of glucose and/or hematin infusions. The pathogenesis of the neuro-psychiatric sympt...

  15. Intermittent fasting attenuates lipopolysaccharide-induced neuroinflammation and memory impairment

    OpenAIRE

    Vasconcelos, Andrea R; Yshii, Lidia M; Viel, Tania A; Buck, Hudson S; Mark P Mattson; Scavone, Cristoforo; Kawamoto, Elisa M

    2014-01-01

    Background Systemic bacterial infections often result in enduring cognitive impairment and are a risk factor for dementia. There are currently no effective treatments for infection-induced cognitive impairment. Previous studies have shown that intermittent fasting (IF) can increase the resistance of neurons to injury and disease by stimulating adaptive cellular stress responses. However, the impact of IF on the cognitive sequelae of systemic and brain inflammation is unknown. Methods Rats on ...

  16. The experience of aggressive outbursts in intermittent explosive disorder

    OpenAIRE

    Kulper, Daniel A.; Kleiman, Evan M.; McCloskey, Michael S.; Berman, Mitchell E.; Coccaro, Emil F.

    2014-01-01

    Conceptualizations of Intermittent Explosive Disorder (IED) have suffered from a scarcity of research investigating the subjective experience and phenomenology of the aggressive outbursts among those with IED relative to those who partake in more normative forms of aggression. Furthermore, though some studies have shown that individuals with IED are more impaired and have a poorer quality of life, few studies looked at negative outcomes specific to an individual with IED’s aggressive behavior...

  17. Intermittent Preventive Antimalarial Treatment for Children with Anaemia.

    OpenAIRE

    Athuman, Mwaka; Kabanywanyi, Abdunoor M; Rohwer, Anke C

    2015-01-01

    Background Anaemia is a global public health problem. Children under five years of age living in developing countries (mostly Africa and South-East Asia) are highly affected. Although the causes for anaemia are multifactorial, malaria has been linked to anaemia in children living in malaria-endemic areas. Administering intermittent preventive antimalarial treatment (IPT) to children might reduce anaemia, since it could protect children from new Plasmodium parasite infection (the parasites tha...

  18. Intermittent drying of beans in a spouted bed

    OpenAIRE

    de Oliveira, C A; S.C.S. Rocha

    2007-01-01

    Carioca beans are a highly nutritious grain, in terms of the amount of protein, iron and potassium as well as carbohydrates and fiber and as a source of vitamins. The moisture content of recently picked beans is too high for good preservation and storage, resulting in the need for drying before packaging. In this work, the drying of Carioca beans in a laboratory scale spouted bed under intermittent conditions of the drying air was experimentally analyzed. Experiments carried out consisted of ...

  19. Merit order effect and strategic investments in intermittent generation technologies

    OpenAIRE

    Silvia Concettini

    2014-01-01

    This paper studies the strategic interactions between two electricity generators, the first producing with a \\traditional" technology and the second employing a \\renewable" technology characterized by the random availability of capacity due to the intermittency of its power source. The competition between the \\traditional" and the \\renewable" power producers is examined through a modified version of the two stage Dixit model for entry deterrence (Dixit, 1980) with Cournot competition in the p...

  20. Consensus of Multiagent Networks with Intermittent Interaction and Directed Topology

    Directory of Open Access Journals (Sweden)

    Li Xiao

    2014-01-01

    Full Text Available Intermittent interaction control is introduced to solve the consensus problem for second-order multiagent networks due to the limited sensing abilities and environmental changes periodically. And, we get some sufficient conditions for the agents to reach consensus with linear protocol from the theoretical findings by using the Lyapunov control approach. Finally, the validity of the theoretical results is validated through the numerical example.

  1. Predicting intermittent running performance: critical velocity versus endurance index.

    Science.gov (United States)

    Buchheit, M; Laursen, P B; Millet, G P; Pactat, F; Ahmaidi, S

    2008-04-01

    The aim of the present study was to examine the ability of the critical velocity (CV) and the endurance index (EI) to assess endurance performance during intermittent exercise. Thirteen subjects performed two intermittent runs: 15-s runs intersected with 15 s of passive recovery (15/15) and 30-s runs with 30-s rest (30/30). Runs were performed until exhaustion at three intensities (100, 95 and 90 % of the speed reached at the end of the 30 - 15 intermittent fitness test, V (IFT)) to calculate i) CV from the slope of the linear relationship between the total covered distance and exhaustion time (ET) (iCV); ii) anaerobic distance capacity from the Y-intercept of the distance/duration relationship (iADC); and iii) EI from the relationship between the fraction of V (IFT) at which the runs were performed and the log-transformed ET (iEI). Anaerobic capacity was indirectly assessed by the final velocity achieved during the Maximal Anaerobic Running Test (VMART). ET was longer for 15/15 than for 30/30 runs at similar intensities. iCV (15/15) and iCV (30/30) were not influenced by changes in ET and were highly dependent on V (IFT). Neither iADC (15/15) nor iADC (30/30) were related to VMART. In contrast, iEI (15/15) was higher than iEI (30/30), and corresponded with the higher ET. In conclusion, only iEI estimated endurance capacity during repeated intermittent running.

  2. Functional independence measure in patients with intermittent claudication

    OpenAIRE

    Caroline Shihara de Assis; Letícia de Carvalho Batista; Nelson Wolosker; Antonio Eduardo Zerati; Rita de Cassia Gengo e Silva

    2015-01-01

    AbstractOBJECTIVEOf this study were to evaluate the functional independence of patients with intermittent claudication and to verify its association with sociodemographic and clinical variables, walking ability and physical activity level.METHODThis was a descriptive, exploratory, cross-sectional study with a quantitative approach. Fifty participants (66.4 years; 68% male) were recruited from Claudication Unit of a tertiary hospital. Functional Independence Measure were used to evaluate funct...

  3. CAN INTERMITTENT VIDEO SAMPLING CAPTURE INDIVIDUAL DIFFERENCES IN NATURALISTIC DRIVING?

    OpenAIRE

    Aksan, Nazan; Schall, Mark; Anderson, Steven; Dawson, Jeffery; Tippin, Jon; Rizzo, Matthew

    2013-01-01

    We examined the utility and validity of intermittent video samples from black box devices for capturing individual difference variability in real-world driving performance in an ongoing study of obstructive sleep apnea (OSA) and community controls. Three types of video clips were coded for several dimensions of interest to driving research including safety, exposure, and driver state. The preliminary findings indicated that clip types successfully captured variability along targeted dimension...

  4. Prolapsed bilateral ureteroceles leading to intermittent outflow obstruction.

    LENUS (Irish Health Repository)

    Stunell, H

    2012-02-01

    A ureterocele refers to a cystic dilatation of the distal ureter. It may be unilateral or bilateral and may be associated with a duplex system in some cases. We present an unusual case where a young patient was found to have large bilateral ureteroceles which prolapsed into the urethra, causing intermittent incontinence and obstruction. We discuss the case and review the literature concerning this rare anomaly.

  5. Single Stage Surgical Outcomes for Large Angle Intermittent Exotropia.

    Directory of Open Access Journals (Sweden)

    Min Yang

    Full Text Available Although there were many prior studies about exotropia, few focused on large-angle intermittent exotropia. The goal of this study was to evaluate single-stage surgical outcomes for large-angle intermittent exotropia and analyze risk factors that may affect the success of surgery. Records from intermittent exotropia patients with exodeviations >60 prism diopters(PD who were surgically treated at the Zhongshan Ophthalmic Center, of Sun Yat-Sen University were reviewed. Included within this review were data on, pre- and post-operative ocular motility, primary alignment, binocular vision and complications. Patients with exodeviations ≤70PD received two-muscle surgery, while those with exodeviations >70PD were subjected to a three-muscle procedure. A total of 40 records were reviewed. The mean exodeviation was 73±9PD at distance and 75±26PD at near. There were 25 patients received two-muscle surgery and 15 the three-muscle procedure. Orthophoria (deviation within 8PD was obtained in 77.5% of these patients and the ratios of surgical under-correction and over-correction were 15% and 7.5% respectively. However, when combining ocular alignment with binocular vision as the success criteria, success rates decreased to 30%. No statistically significant differences in success rates were obtained between the two- and three-muscle surgery groups. Seven subjects experienced an abduction deficit during the initial postoperative stages, but eventually showed a full recovery. One patient required a second surgery for overcorrection. No statistically significant risk factors for poor outcome were revealed. Our data showed that single-stage two- and three-muscle surgeries for large-angle intermittent exotropia are effective in achieving a favorable outcome.

  6. Verbal versus Physical Aggression in Intermittent Explosive Disorder

    OpenAIRE

    Look, Amy E.; McCloskey, Michael S.; Coccaro, Emil F.

    2014-01-01

    Intermittent Explosive Disorder (IED) is the only adult psychiatric diagnosis for which pathological aggression is primary. DSM-IV criteria focused on physical aggression, but DSM-5 allows for an IED diagnosis in the presence of frequent verbal aggression with or without concurrent physical aggression. It remains unclear how individuals with verbal aggression differ from those with physical aggression with respect to cognitive-affective deficits and psychosocial functioning. The current study...

  7. Non-locality and Intermittency in 3D Turbulence

    CERN Document Server

    Laval, J P; Nazarenko, S

    2001-01-01

    Numerical simulations are used to determine the influence of the non-local and local interactions on the intermittency corrections in the scaling properties of 3D turbulence. We show that neglect of local interactions leads to an enhanced small-scale energy spectrum and to a significantly larger number of very intense vortices (tornadoes) and stronger intermittency. On the other hand, neglect of the non-local interactions results in even stronger small-scale spectrum but significantly weaker intermittency. Based on these observations, a new model of turbulence is proposed, in which non-local (RDT-like) interactions couple large and small scale via a multiplicative process with additive noise and the local interactions are modeled by a turbulent viscosity. This model is used to derive a simple toy version of the Langevin equations for small-scale velocity increments. A Gaussian approximation for the large scale fields yields the Fokker-Planck equation for the probability distribution function of the velocity i...

  8. Communication with acute intermittent porphyria patients who have tracheostomy

    Directory of Open Access Journals (Sweden)

    Sevda Arslan

    2013-07-01

    Full Text Available Objective: Introducing acute intermittent porphyria disease and investigating the communication techniques for acute intermittent porphyria patients who have tracheostomyCase Report: 26 years old woman patient consulted to the hospital when she was 13 years old with nausea and vomiting complaints. In 2008, because of respiratory arrest, tracheostomy was implemented to the patient who had acute intermittent porphyria diagnose. The patient had two bullous lesions on the left hand and hyperpigmentation’s on the face and legs. As a result of metabolic acidosis (because of urine disease, the patient was taken to dialysis. After six months of dialysis, hypernatremia was found in the laboratory tests (Na: 85.Period of acute crisis developed In the patient with hypertension, atrophy in the muscles, fainting, abdominal pain, nausea, vomiting and diarrhea. Because of serious diarrhea, TPN was started for the patient who was fed with gavage before. Laboratory test results are Na:126, K:8.1, BUN:23.83, Urine:51, Creatinine:0.94, Leukocyte:20.4, erytrocyte:2.22, Hb:6.87g/dl, Hct: %20.9, Plt:106. Result: It is really difficult to communicate with these patients with lifespan limited because of an extremely severe clinical condition and tracheostomy.

  9. Sulfide elimination by intermittent nitrate dosing in sewer sediments

    Institute of Scientific and Technical Information of China (English)

    Yanchen Liu; Chen Wu; Xiaohong Zhou; David Z.Zhu; Hanchang Shi

    2015-01-01

    The formation of hydrogen sulfide in biofilms and sediments in sewer systems can cause severe pipe corrosions and health hazards,and requires expensive programs for its prevention.The aim of this study is to propose a new control strategy and the optimal condition for sulfide elimination by intermittent nitrate dosing in sewer sediments.The study was carried out based on lab-scale experiments and batch tests using real sewer sediments.The intermittent nitrate dosing mode and the optimal control condition were investigated.The results indicated that the sulfide-intermittent-elimination strategy by nitrate dosing is advantageous for controlling sulfide accumulation in sewer sediment.The oxidation-reduction potential is a sensitive indicator parameter that can reflect the control effect and the minimum N/S (nitrate/sulfide)ratio with slight excess nitrate is necessary for optimal conditions ofefficient sulfide control with lower carbon source loss.The opth-nal control condition is feasible for the sulfide elimination in sewer systems.

  10. Intermittency of rheological regimes in uniform liquid-granular flows.

    Science.gov (United States)

    Armanini, Aronne; Larcher, Michele; Fraccarollo, Luigi

    2009-05-01

    We present a detailed analysis of a free surface-saturated liquid-granular mixture flowing over a static loose bed of grains, where the coexistence of layers dominated by collisional and frictional interactions among particles was observed. Kinetic theory was applied to the flow described above and it proved suitable for describing a realistic behavior of the collisional layers, although it failed to interpret the regions of the flow domain dominated by the frictional contacts. The paper provides a conceptual scheme with which to overcome this problem by focusing on the mechanisms governing the transition from the frictional to the collisional regime. In particular we observed that in highly concentrated flows the transition layer exhibits a typical intermittency of the dominating rheological regime, switching alternately from the frictional to the collisional one. By filtering the velocity signal, we introduced an intermittency function that made it possible to extend the validity of the equations derived from dense gas analogy, typical of the collisional regimes, also in the intermittent phase of the flow. Owing to the small values of the Stokes number, in the application of the kinetic theory we accounted for the possible variation of the elastic restitution coefficient along the flow depth. PMID:19518448

  11. Intermittency and velocity fluctuations in hopper flows prone to clogging

    Science.gov (United States)

    Thomas, C. C.; Durian, D. J.

    2016-08-01

    We study experimentally the dynamics of granular media in a discharging hopper. In such flows, there often appears to be a critical outlet size Dc such that the flow never clogs for D >Dc . We report on the time-averaged velocity distributions, as well as temporal intermittency in the ensemble-averaged velocity of grains in a viewing window, for both D Dc , near and far from the outlet. We characterize the velocity distributions by the standard deviation and the skewness of the distribution of vertical velocities. We propose a measure for intermittency based on the two-sample Kolmogorov-Smirnov DKS statistic for the velocity distributions as a function of time. We find that there is no discontinuity or kink in these various measures as a function of hole size. This result supports the proposition that there is no well-defined Dc and that clogging is always possible. Furthermore, the intermittency time scale of the flow is set by the speed of the grains at the hopper exit. This latter finding is consistent with a model of clogging as the independent sampling for stable configurations at the exit with a rate set by the exiting grain speed [C. C. Thomas and D. J. Durian, Phys. Rev. Lett. 114, 178001 (2015), 10.1103/PhysRevLett.114.178001].

  12. Prolapsing Gastric Polyp Causing Intermittent Gastric Outlet Obstruction.

    Science.gov (United States)

    Kosai, Nik Ritza; Gendeh, Hardip Singh; Norfaezan, Abdul Rashid; Razman, Jamin; Sutton, Paul Anthony; Das, Srijit

    2015-06-01

    Gastric polyps are often an incidental finding on upper gastrointestinal endoscopy, with an incidence up to 5%. The majority of gastric polyps are asymptomatic, occurring secondary to inflammation. Prior reviews discussed Helicobacter pylori (H pylori)-associated singular gastric polyposis; however, we present a rare and unusual case of recurrent multiple benign gastric polyposis post H pylori eradication resulting in intermittent gastric outlet obstruction. A 70-year-old independent male, Chinese in ethnicity, with a background of diabetes mellitus, hypertension, and a simple renal cyst presented with a combination of melena, anemia, and intermittent vomiting of partially digested food after meals. Initial gastroscopy was positive for H pylori; thus he was treated with H pylori eradication and proton pump inhibitors. Serial gastroscopy demonstrated multiple sessile gastric antral polyps, the largest measuring 4 cm. Histopathologic examination confirmed a benign hyperplastic lesion. Computed tomography identified a pyloric mass with absent surrounding infiltration or metastasis. A distal gastrectomy was performed, whereby multiple small pyloric polyps were found, the largest prolapsing into the pyloric opening, thus explaining the intermittent nature of gastric outlet obstruction. Such polyps often develop from gastric ulcers and, if left untreated, may undergo neoplasia to form malignant cells. A distal gastrectomy was an effective choice of treatment, taking into account the polyp size, quantity, and potential for malignancy as opposed to an endoscopic approach, which may not guarantee a complete removal of safer margins and depth. Therefore, surgical excision is favorable for multiple large gastric polyps with risk of malignancy.

  13. Improving Forecasting Accuracy in the Case of Intermittent Demand Forecasting

    Directory of Open Access Journals (Sweden)

    Daisuke Takeyasu

    2014-06-01

    Full Text Available In making forecasting, there are many kinds of data. Stationary time series data are relatively easy to make forecasting but random data are very difficult in its execution for forecasting. Intermittent data are often seen in industries. But it is rather difficult to make forecasting in general. In recent years, the needs for intermittent demand forecasting are increasing because of the constraints of strict Supply Chain Management. How to improve the forecasting accuracy is an important issue. There are many researches made on this. But there are rooms for improvement. In this paper, a new method for cumulative forecasting method is proposed. The data is cumulated and to this cumulated time series, the following method is applied to improve the forecasting accuracy. Trend removing by the combination of linear and 2nd order non-linear function and 3rd order non-linear function is executed to the production data of X-ray image intensifier tube device and Diagnostic X-ray image processing apparatus. The forecasting result is compared with those of the non-cumulative forecasting method. The new method shows that it is useful for the forecasting of intermittent demand data. The effectiveness of this method should be examined in various cases.

  14. Intermittency of solar system plasma turbulence near Venus and Earth

    Science.gov (United States)

    Teodorescu, Eliza; Echim, Marius; Chang, Tom

    2016-04-01

    We analyze magnetic field data from Venus Express (VEX) and CLUSTER to investigate the turbulent properties of the solar wind and the Earth's and Venus' magnetosheaths. A systematic study of the PDFs (Probability Distribution Functions) of the measured magnetic fluctuations and their fourth order moments (kurtosis) reveals numerous intermittent time series. The presence of intermittency is marked by non-Gaussian PDFs with heavy wings and a scale dependent kurtosis. Higher order analyses on the scale dependence of several moment orders of the PDFs, the structure functions, along with the scaling of the kurtosis allow for a selection of scales that pertain to different scaling regimes, governed by different physics. On such sub-ranges of scales we investigate the fractal structure of fluctuations through the Rank Ordered Multifractal Analysis - ROMA (Chang and Wu, 2008). ROMA is applied to a selection of intermittent magnetic field time series in the solar wind and planetary magnetosheaths and helps to quantify the turbulence properties through the estimation of a spectrum of local Hurst exponents. Research supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no 313038/STORM, and a grant of the Romanian Ministry of National Education, CNCS - UEFISCDI, project number PN-II-ID-PCE-2012-4-0418.

  15. Structure functions and intermittency in ionospheric plasma turbulence

    Directory of Open Access Journals (Sweden)

    L. Dyrud

    2008-11-01

    Full Text Available Low frequency electrostatic turbulence in the ionospheric E-region is studied by means of numerical and experimental methods. We use the structure functions of the electrostatic potential as a diagnostics of the fluctuations. We demonstrate the inherently intermittent nature of the low level turbulence in the collisional ionospheric plasma by using results for the space-time varying electrostatic potential from two dimensional numerical simulations. An instrumented rocket can not directly detect the one-point potential variation, and most measurements rely on records of potential differences between two probes. With reference to the space observations we demonstrate that the results obtained by potential difference measurements can differ significantly from the one-point results. It was found, in particular, that the intermittency signatures become much weaker, when the proper rocket-probe configuration is implemented. We analyze also signals from an actual ionospheric rocket experiment, and find a reasonably good agreement with the appropriate simulation results, demonstrating again that rocket data, obtained as those analyzed here, are unlikely to give an adequate representation of intermittent features of the low frequency ionospheric plasma turbulence for the given conditions.

  16. Secondary chronic cluster headache due to trigeminal nerve root compression.

    Science.gov (United States)

    Mjåset, Christer; Russell, M B; Russell, M Bjørn

    2010-12-01

    A 50-year-old woman had a gradual onset of chronic headache located in the right temporal region and a burning sensation in the root of the tongue which over a year evolved into chronic cluster headache with a milder chronic headache in-between the severe cluster headache attacks. A cerebral magnetic resonance imaging (MRI) showed vascular compression of the trigeminal nerve root on the pain side. Neurosurgery microvascular decompression relieved the patient's chronic cluster headache, the chronic intermittent headache and the burning tongue sensation. The effect was persistent at a 1 year follow-up. Patients with atypical symptoms of cluster headache should be examined with cerebral MRI angiography of arteries and veins to exclude symptomatic causes. PMID:20384588

  17. Characterization of wind power resource and its intermittency

    Science.gov (United States)

    Gunturu, U. B.; Schlosser, C. A.

    2011-12-01

    Wind resource in the continental and offshore United States has been calculated and characterized using metrics that describe - apart from abundance - its availability, persistence and intermittency. The Modern Era Retrospective-Analysis for Research and Applications (MERRA) boundary layer flux data has been used to construct wind power density profiles at 50, 80, 100 and 120 m turbine hub heights. The wind power density estimates at 50 m are qualitatively similar to those in the US wind atlas developed by the National Renewable Energy Laboratory (NREL), but quantitatively a class less in some regions, but are within the limits of uncertainty. We also show that for long tailed distributions like those of the wind power density, the mean is an overestimation and median is a more robust metric for summary representation of wind power resource.Generally speaking, the largest and most available wind power density resources are found in off-shore regions of the Atlantic and Pacific coastline, and the largest on-shore resource potential lies in the central United States. However, the intermittency and widespread synchronicity of on-shore wind power density are substantial, and highlights areas where considerable back-up generation technologies will be required. Generation-duration curves are also presented for the independent systems operator (ISO) zones of the U.S. to highlight the regions with the largest capacity factor (MISO, ERCOT, and SWPP) as well as the periods and extent to which all ISOs contain no wind power and the potential benefits of aggregation on wind power intermittency in each region. The impact of raising the wind turbine hub height on metrics of abundance, persistence, variability and intermittency is analyzed. There is a general increase in availability and abundance of wind resource but there is also an increase in intermittency with respect to a 'usable wind power' crossing level in low resource regions. A similar perspective of wind resource for

  18. Chronic cholecystitis

    Science.gov (United States)

    ... foods may relieve symptoms in people. However, the benefit of a low-fat diet has not been proven. Alternative Names Cholecystitis - chronic Images Cholecystitis, CT scan Cholecystitis, cholangiogram Cholecystolithiasis Gallstones, cholangiogram Cholecystogram References Wang ...

  19. Chronic Meningitis

    Science.gov (United States)

    ... School Lunch Lines FDA Cracks Down on Antibacterial Soaps Health Tip: Schedule a Back-to-School Dental ... the Professional Version Meningitis Introduction to Meningitis Acute Bacterial Meningitis Viral Meningitis Noninfectious Meningitis Recurrent Meningitis Chronic ...

  20. Intravenous immunoglobulin treatment in patients with chronic inflammatory demyelinating polyneuropathy.

    OpenAIRE

    van Doorn, P. A.

    1994-01-01

    Intravenous immunoglobulin (IVIg) treatment is shown to be effective in a selected group of patients with a chronic inflammatory demyelinating polyneuropathy (CIDP). The proportion of patients that improve after IVIg treatment varies between studies. Because 40% of a group of IVIg treated CIDP patients needed intermittent IVIg infusions to maintain their improved clinical condition, it is expected that IVIg is effective, at least in this subgroup of patients. However, the proportion of patien...

  1. Two-year home-based nocturnal noninvasive ventilation added to rehabilitation in chronic obstructive pulmonary disease patients : A randomized controlled trial

    NARCIS (Netherlands)

    Duiverman, Marieke L.; Wempe, Johan B.; Bladder, Gerrie; Vonk, Judith M.; Zijlstra, Jan G.; Kerstjens, Huib A. M.; Wijkstra, Peter J.

    2011-01-01

    Background: The use of noninvasive intermittent positive pressure ventilation (NIPPV) in chronic obstructive pulmonary disease (COPD) patients with chronic hypercapnic respiratory failure remains controversial as long-term data are almost lacking. The aim was to compare the outcome of 2-year home-ba

  2. The impact of intermittent umbilical cord occlusions on the inflammatory response in pre-term fetal sheep.

    Directory of Open Access Journals (Sweden)

    Andrew P Prout

    Full Text Available Fetal hypoxic episodes may occur antepartum with the potential to induce systemic and cerebral inflammatory responses thereby contributing to brain injury. We hypothesized that intermittent umbilical cord occlusions (UCOs of sufficient severity but without cumulative acidosis will lead to a fetal inflammatory response. Thirty-one chronically instrumented fetal sheep at ∼0.85 of gestation underwent four consecutive days of hourly UCOs from one to three minutes duration for six hours each day. Maternal and fetal blood samples were taken for blood gases/pH and plasma interleukin (IL-1β and IL-6 levels. Animals were euthanized at the end of experimental study with brain tissue processed for subsequent counting of microglia and mast cells. Intermittent UCOs resulted in transitory fetal hypoxemia with associated acidemia which progressively worsened the longer umbilical blood flow was occluded, but with no cumulative blood gas or pH changes over the four days of study. Fetal arterial IL-1β and IL-6 values showed no significant change regardless of the severity of the UCOs, nor was there any evident impact on the microglia and mast cell counts for any of the brain regions studied. Accordingly, intermittent UCOs of up to three minutes duration with severe, but limited fetal hypoxemia and no cumulative acidemia, do not result in either a systemic or brain inflammatory response in the pre-term ovine fetus. However, fetal IL-1B and IL-6 values were found to be well correlated with corresponding maternal values supporting the placenta as a primary source for these cytokines with related secretion into both circulations. Female fetuses were also found to have higher IL-1β levels than males, indicating that gender may impact on the fetal inflammatory response to various stimuli.

  3. Hepatobiliary scintigraphy in chronic intrahepatic cholestasis. Diagnosis of primary sclerosing cholangitis

    Energy Technology Data Exchange (ETDEWEB)

    Aburano, Tamio; Takayama, Teruhiko; Shuke, Noriyuki

    1987-05-01

    Primary sclerosing cholangitis (PSC) is a rare disease of unknown origin, leading to chronic intermittent cholestasis. Due to its low incidence, insidious clinical onset and varied clinical picture, the diagnosis is often delayed by years. PSC is sometimes diagnosed falsely as another disease of chronic intermittent cholestasis, primary biliary cirrhosis (PBC). In the present study, the hepatobiliary imaging with Tc-99m diethyl IDA was done in a total of 14 patients with chronic intermittent cholestasis including 3 patients with PSC and 11 patients with PBC, in order to decide its clinical usefulness as a noninvasive method for the differentiation between PSC and PBC. All three patients with PSC showed a typical pattern of radionuclide stasis within the area of intrahepatic and/or extrahepatic ductal system, representing the stenosis on endoscopic retrograde cholangiogram. On the other hand, none of 11 patients with PBC showed any radionuclide stasis within the area of intrahepatic and/or extrahepatic ductal system. This result suggests that the radionuclide hepatobiliary imaging may be a noninvasive method for investigating patients with chronic intermittent cholestasis, leading to earlier differentiation between PSC and PBC.

  4. RESPONSES OF SUBJECTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE AFTER EXPOSURES TO 0.3 PPM OZONE

    Science.gov (United States)

    The authors previously reported (1982) that the respiratory mechanics of intermittently exercising persons with chronic obstructive pulmonary disease (COPD) were unaffected by a 2-h exposure to 0.2 ppm ozone. Employing a single-blind cross-over design protocol, 13 white men with ...

  5. Tuina plus Acupuncture for Chronic Fatigue Syndrome:A Report of 87 Cases

    Institute of Scientific and Technical Information of China (English)

    张克军; 韩丑萍

    2009-01-01

    @@ Officially defined by the US Centers for DiseaseControl and Prevention(CDC),Chronic FatigueSyndrome(CFS)is mainly characterized by a persistent or intermittent fatigue and can greatly endanger human health[1]The author treated 87 CFS cases in the past two years with tuina plus acupuncture.The report is now as follows.

  6. Intermittency in MHD turbulence and coronal nanoflares modelling

    Directory of Open Access Journals (Sweden)

    P. Veltri

    2005-01-01

    Full Text Available High resolution numerical simulations, solar wind data analysis, and measurements at the edges of laboratory plasma devices have allowed for a huge progress in our understanding of MHD turbulence. The high resolution of solar wind measurements has allowed to characterize the intermittency observed at small scales. We are now able to set up a consistent and convincing view of the main properties of MHD turbulence, which in turn constitutes an extremely efficient tool in understanding the behaviour of turbulent plasmas, like those in solar corona, where in situ observations are not available. Using this knowledge a model to describe injection, due to foot-point motions, storage and dissipation of MHD turbulence in coronal loops, is built where we assume strong longitudinal magnetic field, low beta and high aspect ratio, which allows us to use the set of reduced MHD equations (RMHD. The model is based on a shell technique in the wave vector space orthogonal to the strong magnetic field, while the dependence on the longitudinal coordinate is preserved. Numerical simulations show that injected energy is efficiently stored in the loop where a significant level of magnetic and velocity fluctuations is obtained. Nonlinear interactions give rise to an energy cascade towards smaller scales where energy is dissipated in an intermittent fashion. Due to the strong longitudinal magnetic field, dissipative structures propagate along the loop, with the typical speed of the Alfvén waves. The statistical analysis on the intermittent dissipative events compares well with all observed properties of nanoflare emission statistics. Moreover the recent observations of non thermal velocity measurements during flare occurrence are well described by the numerical results of the simulation model. All these results naturally emerge from the model dynamical evolution without any need of an ad-hoc hypothesis.

  7. Hybrid optimal scheduling for intermittent androgen suppression of prostate cancer

    Science.gov (United States)

    Hirata, Yoshito; di Bernardo, Mario; Bruchovsky, Nicholas; Aihara, Kazuyuki

    2010-12-01

    We propose a method for achieving an optimal protocol of intermittent androgen suppression for the treatment of prostate cancer. Since the model that reproduces the dynamical behavior of the surrogate tumor marker, prostate specific antigen, is piecewise linear, we can obtain an analytical solution for the model. Based on this, we derive conditions for either stopping or delaying recurrent disease. The solution also provides a design principle for the most favorable schedule of treatment that minimizes the rate of expansion of the malignant cell population.

  8. Intermittency in hadronic decays of the Z sup 0

    Energy Technology Data Exchange (ETDEWEB)

    Akrawy, M.Z.; Alexander, G.; Allison, J.; Allport, P.P.; Anderson, K.J.; Armitage, J.C.; Ashton, P.; Astbury, A.; Axen, D.; Azuelos, G.; Baines, J.T.M.; Ball, A.H.; Banks, J.; Barker, G.J.; Barlow, R.J.; Batley, J.R.; Beaudoin, G.; Beck, A.; Becker, J.; Behnke, T.; Bell, K.W.; Bella, G.; Bethke, S.; Biebel, O.; Binder, U.; Bloodworth, I.J.; Bock, P.; Bougerolle, S.; Brabson, B.B.; Breuker, H.; Brown, R.M.; Brun, R.; Buijs, A.; Burckhart, H.J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Chrin, J.T.M.; Clarke, P.E.L.; Cohen, I.; Collins, W.J.; Conboy, J.E.; Cooper, M.; Couch, M.; Coupland, M.; Cuffiani, M.; Dado, S.; Dallavalle, G.M.; De Jong, S.; Debu, P.; Deninno, M.M.; Dieckmann, A.; Dittmar, M.; Dixit, M.S.; Duchovni, E.; Duerdoth, I.P.; Dumas, D.J.P.; Elcombe, P.A.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Farthouat, P.; Fincke-Keeler, M.; Fischer, H.M.; Fong, D.G.; Fukunaga, C.; Gaidot, A.; Ganel, O.; Gary, J.W.; Gascon, J.; Geddes, N.I; OPAL Collaboration

    1991-06-20

    A factorial moment analysis has been performed on the differential multiplicity distributions of hadronic final states of the Z{sup 0} recorded with the OPAL detector at LEP. The moments of the one-dimensional rapidity and the two-dimensional rapidity versus azimuthal angle distributions are found to exhibit 'intermittent' behaviour attributable to the jet structure of the events. The moments are reproduced by both parton shower and matrix element QCD based hadronisation models. No evidence for fluctuations beyond those attributable to jet structure is observed. (orig.).

  9. Intermittency induced long-range cross-correlations

    CERN Document Server

    Diakonos, Fotis K; Schmelcher, Peter

    2013-01-01

    Cross-correlations are usually considered to emerge through interaction between particles. Here we present a mechanism capable to generate power-law cross-correlations between non-interacting particles exposed to an external potential. This phenomenon can occur as an ensemble property when the external potential induces intermittent dynamics, providing laminar and stochastic phases of motion. We have strong indications that the divergence of the mean residence time in the laminar phase of the single particle motion - sporadic dynamics - is a sufficient condition for the emergence of long-range cross-correlations. We argue that this mechanism may be relevant for the occurrence of collective behaviour in critical systems.

  10. Intermittent versus Continuous Incremental Field Tests: Are Maximal Variables Interchangeable?

    Science.gov (United States)

    Carminatti, Lorival J; Possamai, Carlos A P; de Moraes, Marcelo; da Silva, Juliano F; de Lucas, Ricardo D; Dittrich, Naiandra; Guglielmo, Luiz G A

    2013-01-01

    The aim of the present study was to compare physiological responses derived from an incremental progressive field test with a constant speed test i.e. intermittent versus continuous protocol. Two progressive maximum tests (Carminatti`s test (T-CAR) and the Vameval test (T-VAM)), characterized by increasing speed were used. T-CAR is an intermittent incremental test, performed as shuttle runs; while T-VAM is a continuous incremental test performed on an athletic track. Eighteen physically active, healthy young subjects (21.9 ± 2.0 years; 76.5 ± 8.6 kg, 1.78 ± 0.08 m, 11.2 ± 5.4% body fat), volunteered for this study. Subjects performed four different maximum test sessions conducted in the field: two incremental tests and two time to exhaustion tests (TTE) at peak test velocities (PV). No significant differences were found for PV (T-CAR = 15.6 ± 1.2; T-VAM = 15.5 ± 1.3 km·h(-1)) and maximal HR (T-CAR = 195 ± 11; T- VAM = 194 ± 14 bpm). During TTE, there were no significant differences for HR (TTET-CAR and TTET-VAM = 192 ± 12 bpm). However, there was a significant difference in TTE (p = 0.04) (TTET-CAR = 379 ± 84, TTET-VAM = 338 ± 58 s) with a low correlation (r = 0.41). The blood lactate concentration measured at the end of the TTE tests, showed no significant difference (TTET-CAR = 13.2 ± 2.4 vs. TTET-VAM = 12.9 ± 2.4 mmol·l(-1)). Based on the present findings, it is suggested that the maximal variables derived from T-CAR and T-VAM can be interchangeable in the design of training programs. Key pointsT-CAR is an intermittent shuttle run test that predicts the maximal aerobic speed with accuracy, hence, test results could be interchangeable with continuous straight-line tests.T-CAR provides valid field data for evaluating aerobic fitness.In comparison with T-VAM, T-CAR may be a more favourable way to prescribe intermittent training using a shuttle-running protocol.

  11. Carbon-Carbon Turbocharger Housing Unit for Intermittent Combustion Engines

    Science.gov (United States)

    Northam, G. Burton (Inventor); Ransone, Philip O. (Inventor); Rivers, H. Kevin (Inventor)

    1998-01-01

    An improved, lightweight, turbine housing unit for an intermittent combustion reciprocating internal combustion engine turbocharger is prepared from a lay-up or molding of carbon-carbon composite materials in a single-piece or two-piece process. When compared to conventional steel or cast iron, the use of carbon-carbon composite materials in a turbine housing unit reduces the overall weight of the engine and reduces the heat energy loss used in the turbocharging process. This reduction in heat energy loss and weight reduction provides for more efficient engine operation.

  12. Percutaneous transluminal angioplasty of infrarenal arteries in intermittent claudication

    DEFF Research Database (Denmark)

    Henriksen, L O; Jørgensen, B; Holstein, P E;

    1988-01-01

    Percutaneous transluminal angioplasty was performed on 55 iliac and 31 femoropopliteal arteries in 71 patients with intermittent claudication (23 women, 48 men). The two-year patency rate was 80% after iliac and 41% after femoropopliteal angioplasty. In 17 femoropopliteal cases with lesions greater...... than or equal to 5 cm the 2-year patency rate was only 32%, but the corresponding figure for shorter lesions was 53%. Complicating haematoma appeared in 10% of the cases and the arterial state deteriorated in one patient. There was no distal embolization. Percutaneous transluminal angioplasty...

  13. Google matrix and Ulam networks of intermittency maps.

    Science.gov (United States)

    Ermann, L; Shepelyansky, D L

    2010-03-01

    We study the properties of the Google matrix of an Ulam network generated by intermittency maps. This network is created by the Ulam method which gives a matrix approximant for the Perron-Frobenius operator of dynamical map. The spectral properties of eigenvalues and eigenvectors of this matrix are analyzed. We show that the PageRank of the system is characterized by a power law decay with the exponent beta dependent on map parameters and the Google damping factor alpha . Under certain conditions the PageRank is completely delocalized so that the Google search in such a situation becomes inefficient.

  14. Intermittent duty solar refrigerator assisted by heat pipes

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hindi, R.R.; Khalifa, A.M.A.; Akyurt, M.

    1988-01-01

    The design of a solar operated intermittent-duty aqua-ammonia type of absorption refrigerator is described. The generator is heated by an integral acetone heat pipe, the evaporator of which is in the form of a low-thermal-mass flat plate collector. The condenser is air cooled. The absorber is likewise cooled via a second R22 heat-pipe system by convection/radiation panels. Initial test results for the collector-generator loop are reported for a single-glazed collector. A discussion of overall performance is presented.

  15. Atomistic Model of Fluorescence Intermittency of Colloidal Quantum Dots

    KAUST Repository

    Voznyy, O.

    2014-04-16

    Optoelectronic applications of colloidal quantum dots demand a high emission efficiency, stability in time, and narrow spectral bandwidth. Electronic trap states interfere with the above properties but understanding of their origin remains lacking, inhibiting the development of robust passivation techniques. Here we show that surface vacancies improve the fluorescence yield compared to vacancy-free surfaces, while dynamic vacancy aggregation can temporarily turn fluorescence off. We find that infilling with foreign cations can stabilize the vacancies, inhibiting intermittency and improving quantum yield, providing an explanation of recent experimental observations. © 2014 American Physical Society.

  16. Monitoring antifolate resistance in intermittent preventive therapy for malaria

    DEFF Research Database (Denmark)

    Venkatesan, Meera; Alifrangis, Michael; Roper, Cally;

    2013-01-01

    Mutations in the Plasmodium falciparum genes Pfdhfr and Pfdhps have rendered sulfadoxine-pyrimethamine (SP) ineffective for malaria treatment in most regions of the world. Yet, SP is efficacious as intermittent preventive therapy in pregnant women (IPTp) and infants (IPTi) and as seasonal malaria...... control in children (SMC). SP-IPTp is being widely implemented in sub-Saharan Africa. SP-IPTi is recommended where the prevalence of SP-resistant malaria parasites is low, whereas SMC is recommended for areas of intense seasonal malaria transmission. The continuing success of these interventions depends...

  17. Intermittent contact atomic force microscopy in electrochemical environment

    Energy Technology Data Exchange (ETDEWEB)

    Haering, P.; Koetz, R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Siegenthaler, H. [Bern Univ., Bern (Switzerland)

    1997-06-01

    In situ measurements with Atomic Force Microscopy may cause surface modifications due to the tip-surface interactions. As an alternative and less destructive method, Intermittent Contact Atomic Force Microscopy (ICAFM) has been tested in an electrolytic environment. In the ICAFM mode the tip is not constantly in contact with the surface under investigation but is tapping onto the surface with a certain frequency. A commercial Park Scientific Instruments Microscopy has been modified to enable in situ experiment with ICAFM. It was possible to image iridium oxide films with ICAFM in the electrolytic environment without any noticeable surface modifications. (author) 3 figs., 4 refs.

  18. Influence of intermittency on the anisotropy of magnetic structure functions of solar wind turbulence

    Science.gov (United States)

    Pei, Zhongtian; He, Jiansen; Wang, Xin; Tu, Chuanyi; Marsch, Eckart; Wang, Linghua; Yan, Limei

    2016-02-01

    Intermittency appears to be connected with the spectral anisotropy of solar wind turbulence. We use the Local Intermittency Measure to identify and remove intermittency from the magnetic field data measured by the Ulysses spacecraft in fast solar wind. Structure functions are calculated based on the time sequences as obtained before and after removing intermittency and arranged by time scale (τ) and ΘRB (the angle between local mean magnetic field B0 and radial direction R). Thus, the scaling exponent (ξ(p, ΘRB)) of every structure function of order (p) is obtained for different angles. Before removing intermittency, ξ(p, ΘRB) shows a distinctive dependence on ΘRB: from monofractal scaling law at ΘRB ~0° to multifractal scaling law at ΘRB ~90°. In contrast after eliminating the intermittency, ξ(p, ΘRB) is found to be more monofractal for all ΘRB. The extended structure-function model is applied to ξ(p, ΘRB), revealing differences of its fitting parameters α (a proxy of the power spectral index) and P1 (fragmentation fraction) for the cases with and without intermittency. Parameter α shows an evident angular trend falling from 1.9 to 1.6 for the case with intermittency but has a relatively flat profile around 1.8 for the case without intermittency. Parameter P1 rises from around 0.5 to above 0.8 with increasing ΘRB for the intermittency case and is located between 0.5 and 0.8 for the case lacking intermittency. Therefore, we may infer that it is the anisotropy of intermittency that causes the scaling anisotropy of energy spectra and the unequal fragmentation of energy cascading.

  19. AMP: a new time-frequency feature extraction method for intermittent time-series data

    OpenAIRE

    Barrack, Duncan; Goulding, James; Hopcraft, Keith; Preston, Simon; Smith, Gavin

    2015-01-01

    The characterisation of time-series data via their most salient features is extremely important in a range of machine learning task, not least of all with regards to classification and clustering. While there exist many feature extraction techniques suitable for non-intermittent time-series data, these approaches are not always appropriate for intermittent time-series data, where intermittency is characterized by constant values for large periods of time punctuated by sharp and transient incr...

  20. Blood lactate level in Wistar rats after four and twelve week intermittent aerobic training

    OpenAIRE

    Dewi N. Sari; Sutjahjo Endardjo; Dewi I.S. Santoso

    2013-01-01

    Background: Aerobic training can be done not only continuously, but also intermittently. Intermittent aerobic training aimed to get blood lactate level lower than continuous aerobic training. Blood lactate concentration in one of the various factors that determine training performance. However, until recently, little studies about intermittent aerobic training and blood lactate levels have been done. Therefore, this study aimed to measure blood lactate levels in Wistar rats after 4 and 12 wee...

  1. Efficacious intermittent dosing of a novel JAK2 inhibitor in mouse models of polycythemia vera.

    Directory of Open Access Journals (Sweden)

    Manfred Kraus

    Full Text Available A high percentage of patients with the myeloproliferative disorder polycythemia vera (PV harbor a Val617→Phe activating mutation in the Janus kinase 2 (JAK2 gene, and both cell culture and mouse models have established a functional role for this mutation in the development of this disease. We describe the properties of MRLB-11055, a highly potent inhibitor of both the WT and V617F forms of JAK2, that has therapeutic efficacy in erythropoietin (EPO-driven and JAK2V617F-driven mouse models of PV. In cultured cells, MRLB-11055 blocked proliferation and induced apoptosis in a manner consistent with JAK2 pathway inhibition. MRLB-11055 effectively prevented EPO-induced STAT5 activation in the peripheral blood of acutely dosed mice, and could prevent EPO-induced splenomegaly and erythrocytosis in chronically dosed mice. In a bone marrow reconstituted JAK2V617F-luciferase murine PV model, MRLB-11055 rapidly reduced the burden of JAK2V617F-expressing cells from both the spleen and the bone marrow. Using real-time in vivo imaging, we examined the kinetics of disease regression and resurgence, enabling the development of an intermittent dosing schedule that achieved significant reductions in both erythroid and myeloid populations with minimal impact on lymphoid cells. Our studies provide a rationale for the use of non-continuous treatment to provide optimal therapy for PV patients.

  2. [Intermittent or persistent rhinitis in children and adolescents with Asthma: «the Swiss LARA paediatrics survey»].

    Science.gov (United States)

    Leuppi, J D; Wildhaber, J H; Spertini, F; Helbling, A

    2011-10-01

    Asthma and allergic rhinitis are chronic inflammatory airway diseases which often occur concomitantly. The objective of the LARA program was to identify the comorbidities and characteristics of asthma (A), intermittent or persistent rhinitis (IPR) and physician defined atopic dermatitis (AD) in 6- to 16-year old asthmatic Swiss children and adolescents. Overall, 126 general practitioners and paediatricians collected the data of 670 asthmatics. Approximately one third of the asthmatic children in Switzerland had well-controlled asthma. Almost two thirds of these asthmatics suffered from concomitant IPR. The latter presented with significantly less symptoms while the treatment rates with inhaled corticosteroids (approximately 90%) and leukotriene-receptorantagonists (approximately 50%) were comparable. However, there were almost twice as many passive smokers in the less well-controlled group. The prevalence of AD was similar in both groups. IPR and AD may play an important role as risk factors in the future development of asthma. PMID:21971616

  3. Chronic myelogenous leukemia (CML)

    Science.gov (United States)

    CML; Chronic myeloid leukemia; Chronic granulocytic leukemia; Leukemia - chronic granulocytic ... nuclear disaster. It takes many years to develop leukemia from radiation exposure. Most people treated for cancer ...

  4. Chronic obstructive pulmonary disease

    Science.gov (United States)

    ... airways disease; Chronic obstructive lung disease; Chronic bronchitis; Emphysema; Bronchitis - chronic ... a protein called alpha-1 antitrypsin can develop emphysema. Other risk factors for COPD are: Exposure to ...

  5. Intermittent Demand Forecasting in a Tertiary Pediatric Intensive Care Unit.

    Science.gov (United States)

    Cheng, Chen-Yang; Chiang, Kuo-Liang; Chen, Meng-Yin

    2016-10-01

    Forecasts of the demand for medical supplies both directly and indirectly affect the operating costs and the quality of the care provided by health care institutions. Specifically, overestimating demand induces an inventory surplus, whereas underestimating demand possibly compromises patient safety. Uncertainty in forecasting the consumption of medical supplies generates intermittent demand events. The intermittent demand patterns for medical supplies are generally classified as lumpy, erratic, smooth, and slow-moving demand. This study was conducted with the purpose of advancing a tertiary pediatric intensive care unit's efforts to achieve a high level of accuracy in its forecasting of the demand for medical supplies. On this point, several demand forecasting methods were compared in terms of the forecast accuracy of each. The results confirm that applying Croston's method combined with a single exponential smoothing method yields the most accurate results for forecasting lumpy, erratic, and slow-moving demand, whereas the Simple Moving Average (SMA) method is the most suitable for forecasting smooth demand. In addition, when the classification of demand consumption patterns were combined with the demand forecasting models, the forecasting errors were minimized, indicating that this classification framework can play a role in improving patient safety and reducing inventory management costs in health care institutions. PMID:27562485

  6. Emission Enhancement and Intermittency in Polycrystalline Organolead Halide Perovskite Films

    Directory of Open Access Journals (Sweden)

    Cheng Li

    2016-08-01

    Full Text Available Inorganic-organic halide organometal perovskites have demonstrated very promising performance for opto-electronic applications, such as solar cells, light-emitting diodes, lasers, single-photon sources, etc. However, the little knowledge on the underlying photophysics, especially on a microscopic scale, hampers the further improvement of devices based on this material. In this communication, correlated conventional photoluminescence (PL characterization and wide-field PL imaging as a function of time are employed to investigate the spatially- and temporally-resolved PL in CH3NH3PbI3−xClx perovskite films. Along with a continuous increase of the PL intensity during light soaking, we also observe PL blinking or PL intermittency behavior in individual grains of these films. Combined with significant suppression of PL blinking in perovskite films coated with a phenyl-C61-butyric acid methyl ester (PCBM layer, it suggests that this PL intermittency is attributed to Auger recombination induced by photoionized defects/traps or mobile ions within grains. These defects/traps are detrimental for light conversion and can be effectively passivated by the PCBM layer. This finding paves the way to provide a guideline on the further improvement of perovskite opto-electronic devices.

  7. Intermittent Water Supply: Prevalence, Practice, and Microbial Water Quality.

    Science.gov (United States)

    Kumpel, Emily; Nelson, Kara L

    2016-01-19

    Intermittent water supplies (IWS), in which water is provided through pipes for only limited durations, serve at least 300 million people around the world. However, providing water intermittently can compromise water quality in the distribution system. In IWS systems, the pipes do not supply water for periods of time, supply periods are shortened, and pipes experience regular flow restarting and draining. These unique behaviors affect distribution system water quality in ways that are different than during normal operations in continuous water supplies (CWS). A better understanding of the influence of IWS on mechanisms causing contamination can help lead to incremental steps that protect water quality and minimize health risks. This review examines the status and nature of IWS practices throughout the world, the evidence of the effect of IWS on water quality, and how the typical contexts in which IWS systems often exist-low-income countries with under-resourced utilities and inadequate sanitation infrastructure-can exacerbate mechanisms causing contamination. We then highlight knowledge gaps for further research to improve our understanding of water quality in IWS.

  8. Horizontal visibility graphs generated by type-I intermittency

    Science.gov (United States)

    Núñez, Ángel M.; Luque, Bartolo; Lacasa, Lucas; Gómez, Jose Patricio; Robledo, Alberto

    2013-05-01

    The type-I intermittency route to (or out of) chaos is investigated within the horizontal visibility (HV) graph theory. For that purpose, we address the trajectories generated by unimodal maps close to an inverse tangent bifurcation and construct their associated HV graphs. We show how the alternation of laminar episodes and chaotic bursts imprints a fingerprint in the resulting graph structure. Accordingly, we derive a phenomenological theory that predicts quantitative values for several network parameters. In particular, we predict that the characteristic power-law scaling of the mean length of laminar trend sizes is fully inherited by the variance of the graph degree distribution, in good agreement with the numerics. We also report numerical evidence on how the characteristic power-law scaling of the Lyapunov exponent as a function of the distance to the tangent bifurcation is inherited in the graph by an analogous scaling of block entropy functionals defined on the graph. Furthermore, we are able to recast the full set of HV graphs generated by intermittent dynamics into a renormalization-group framework, where the fixed points of its graph-theoretical renormalization-group flow account for the different types of dynamics. We also establish that the nontrivial fixed point of this flow coincides with the tangency condition and that the corresponding invariant graph exhibits extremal entropic properties.

  9. Intermittent Demand Forecasting in a Tertiary Pediatric Intensive Care Unit.

    Science.gov (United States)

    Cheng, Chen-Yang; Chiang, Kuo-Liang; Chen, Meng-Yin

    2016-10-01

    Forecasts of the demand for medical supplies both directly and indirectly affect the operating costs and the quality of the care provided by health care institutions. Specifically, overestimating demand induces an inventory surplus, whereas underestimating demand possibly compromises patient safety. Uncertainty in forecasting the consumption of medical supplies generates intermittent demand events. The intermittent demand patterns for medical supplies are generally classified as lumpy, erratic, smooth, and slow-moving demand. This study was conducted with the purpose of advancing a tertiary pediatric intensive care unit's efforts to achieve a high level of accuracy in its forecasting of the demand for medical supplies. On this point, several demand forecasting methods were compared in terms of the forecast accuracy of each. The results confirm that applying Croston's method combined with a single exponential smoothing method yields the most accurate results for forecasting lumpy, erratic, and slow-moving demand, whereas the Simple Moving Average (SMA) method is the most suitable for forecasting smooth demand. In addition, when the classification of demand consumption patterns were combined with the demand forecasting models, the forecasting errors were minimized, indicating that this classification framework can play a role in improving patient safety and reducing inventory management costs in health care institutions.

  10. [Denitrification water treatment with zeolite composite filter by intermittent operation].

    Science.gov (United States)

    Qing, Cheng-Song; Bao, Tao; Chen, Tian-Hu; Chen, Dong; Xie, Jing-Jing

    2012-12-01

    The zeolite composite filters (ZCF) with the size of4-8 mm were prepared using raw zeolite (0.15-0.18 mm) as the main material and the cement as binder. After a combination of material characterizations, such as the void fraction, apparent density, compression strength and surface area, the optimal prepared conditions of composite filters were obtained as follow: weight ratio of m (zeolite): m (cement) = 7 : 3, curing for 15 d under the moisture condition and ambient temperature. Through upflow low-concentration ammonia nitrogen wastewater, ZCF filled in the experimental column was hung with the biological membrane. Thus, intermittent dynamic experiments were conducted, the intermittent operation cycle included adsorption, biological regeneration and drip washing. Until concentration of ammonia nitrogen was more than 2 mg x L(-1) of effluent standards, water in experiment column was firstly emptied, and then blast biological regeneration was conducted. After the filters were bathed with water, the zeolite adsorption-biological regeneration cycle was performed repeatedly. The experimental results show that under conditions of 24 h blast and 5 d of continuous operation period, ammonia nitrogen removal rate is up to 87.6% on average, total nitrogen removal rate reaches 51.2% on average. PMID:23379168

  11. Twist-induced Magnetosphere Reconfiguration for Intermittent Pulsars

    CERN Document Server

    Huang, Lei; Tong, Hao

    2016-01-01

    We propose that the magnetosphere reconfiguration induced by magnetic twists in the closed field line region can account for the mode-switching of intermittent pulsars. We carefully investigate the properties of axisymmetric force-free pulsar magnetospheres with magnetic twists in closed field line region around the polar caps. The magnetosphere with twisted closed lines leads to enhanced spin-down rates. The enhancement in spin-down rate depends on the size of region with twisted closed lines. Typically, it is increased by a factor of $\\sim2$, which is consistent with the intermittent pulsars' spin down behavior during the `off' and `on' states. We find there is a threshold of maximal twist angle $\\Delta\\phi_{\\rm thres}\\sim1$. The magnetosphere is stable only if the closed line twist angle is less than $\\Delta\\phi_{\\rm thres}$. Beyond this value, the magnetosphere becomes unstable and gets untwisted. The spin-down rate would reduce to its off-state value. The quasi-periodicity in spin-down rate change can be...

  12. Antral hyperplastic polyp causing intermittent gastric outlet obstruction: Case report

    Directory of Open Access Journals (Sweden)

    Kurtkaya-Yapicier Ozlem

    2003-06-01

    Full Text Available Abstract Background Hyperplastic polyps are the most common polypoid lesions of the stomach. Rarely, they cause gastric outlet obstruction by prolapsing through the pyloric channel, when they arise in the prepyloric antrum. Case presentation A 62-year-old woman presented with intermittent nausea and vomiting of 4 months duration. Upper gastrointestinal endoscopy revealed a 30 mm prepyloric sessile polyp causing intermittent gastric outlet obstruction. Following submucosal injection of diluted adrenaline solution, the polyp was removed with a snare. Multiple biopsies were taken from the greater curvature of the antrum and the corpus. Rapid urease test for Helicobacter pylori yielded a negative result. Histopathologic examination showed a hyperplastic polyp without any evidence of malignancy. Biopsies of the antrum and the corpus revealed gastritis with neither atrophic changes nor Helicobacter pylori infection. Follow-up endoscopy after a 12-week course of proton pomp inhibitor therapy showed a complete healing without any remnant tissue at the polypectomy site. The patient has been symptom-free during 8 months of follow-up. Conclusions Symptomatic gastric polyps should be removed preferentially when they are detected at the initial diagnostic endoscopy. Polypectomy not only provides tissue to determine the exact histopathologic type of the polyp, but also achieves radical treatment.

  13. INTERMITTENT CLONAZEPAM IN THE PREVENTION OF RECURRENT FEBRILE SEIZURES

    Directory of Open Access Journals (Sweden)

    BAJOGHLI Shirin MD

    2010-09-01

    Full Text Available ObjectiveTo evaluate the efficacy and common side effects of intermittent clonazepamin febrile seizures.Materials & MethodsThis study was an experimental trial designed to determine the efficacy ofintermittent clonazepam in febrile seizures .Thirty patients with an age rangeof 6 months to 5 years (60% male, 40% female were studied. Children with ahistory of psychomotor delay, abnormal neurological examination, a history ofantiepileptic drug consumption, and afebrile seizures were excluded from thestudy. Patients received a single dose of prophylactic Clonazepam (0.05 mg/kg/day on the first day of febrile illness and twice daily during the course of fever.An antipyretic medication (Acetaminophen was advised if fever exceeded38oC. Patients were followed up for one year after the study inclusion date.ResultsThree patients were excluded from study since they didnot follow the tritmentand three patients experienced afebrile seizures. Twenty four patients had 162febrile episodes during the course of the study and all patients were seizure-freeafter 1 year.ConclusionClonazepam was 100% effective but lethargy and ataxia were common sideeffects in patients. Fortunately, their parents continued treatment because theyhad prior awareness of the possible side effects of clonazepam. Clonazepam isefficacious as an intermittent therapy for febrile seizures if parents are informedof its side effects.

  14. Emission Enhancement and Intermittency in Polycrystalline Organolead Halide Perovskite Films.

    Science.gov (United States)

    Li, Cheng; Zhong, Yu; Luna, Carlos Andres Melo; Unger, Thomas; Deichsel, Konstantin; Gräser, Anna; Köhler, Jürgen; Köhler, Anna; Hildner, Richard; Huettner, Sven

    2016-01-01

    Inorganic-organic halide organometal perovskites have demonstrated very promising performance for opto-electronic applications, such as solar cells, light-emitting diodes, lasers, single-photon sources, etc. However, the little knowledge on the underlying photophysics, especially on a microscopic scale, hampers the further improvement of devices based on this material. In this communication, correlated conventional photoluminescence (PL) characterization and wide-field PL imaging as a function of time are employed to investigate the spatially- and temporally-resolved PL in CH₃NH₃PbI3-xClx perovskite films. Along with a continuous increase of the PL intensity during light soaking, we also observe PL blinking or PL intermittency behavior in individual grains of these films. Combined with significant suppression of PL blinking in perovskite films coated with a phenyl-C61-butyric acid methyl ester (PCBM) layer, it suggests that this PL intermittency is attributed to Auger recombination induced by photoionized defects/traps or mobile ions within grains. These defects/traps are detrimental for light conversion and can be effectively passivated by the PCBM layer. This finding paves the way to provide a guideline on the further improvement of perovskite opto-electronic devices. PMID:27548128

  15. Reconstructing the intermittent dynamics of the torque in wind turbines

    CERN Document Server

    Lind, Pedro G; Peinke, Joachim

    2014-01-01

    We apply a framework introduced in the late nineties to analyze load measurements in off-shore wind energy converters (WEC). The framework is borrowed from statistical physics and properly adapted to the analysis of multivariate data comprising wind velocity, power production and torque measurements, taken at one single WEC. In particular, we assume that wind statistics drives the fluctuations of the torque produced in the wind turbine and show how to extract an evolution equation of the Langevin type for the torque driven by the wind velocity. It is known that the intermittent nature of the atmosphere, i.e. of the wind field, is transferred to the power production of a wind energy converter and consequently to the shaft torque. We show that the derived stochastic differential equation quantifies the dynamical coupling of the measured fluctuating properties as well as it reproduces the intermittency observed in the data. Finally, we discuss our approach in the light of turbine monitoring, a particular importa...

  16. Mechanisms affecting water quality in an intermittent piped water supply.

    Science.gov (United States)

    Kumpel, Emily; Nelson, Kara L

    2014-01-01

    Drinking water distribution systems throughout the world supply water intermittently, leaving pipes without pressure between supply cycles. Understanding the multiple mechanisms that affect contamination in these intermittent water supplies (IWS) can be used to develop strategies to improve water quality. To study these effects, we tested water quality in an IWS system with infrequent and short water delivery periods in Hubli-Dharwad, India. We continuously measured pressure and physicochemical parameters and periodically collected grab samples to test for total coliform and E. coli throughout supply cycles at 11 sites. When the supply was first turned on, water with elevated turbidity and high concentrations of indicator bacteria was flushed out of pipes. At low pressures (pressures between 10 and 17 psi, evidence of periodic contamination suggested that transient intrusion, backflow, release of particulates, or sloughing of biofilms from pipe walls had occurred. Few total coliform and no E. coli were detected when water was delivered with a chlorine residual and at pressures >17 psi. PMID:24459990

  17. Bubble shape in horizontal and near horizontal intermittent flow

    International Nuclear Information System (INIS)

    Highlights: • The bubble shapes in intermittent flows are presented experimentally. • The nose-tail inversion phenomenon appears at a low Froude number in downward pipe. • Transition from plug to slug flow occurs when the bubble tail changes from staircase pattern to hydraulic jump. - Abstract: This paper presents an experimental study of the shape of isolated bubbles in horizontal and near horizontal intermittent flows. It is found that the shapes of the nose and body of bubble depend on the Froude number defined by gas/liquid mixture velocity in a pipe, whereas the shape of the back of bubble region depends on both the Froude number and bubble length. The photographic studies show that the transition from plug to slug flow occurs when the back of the bubble changes from staircase pattern to hydraulic jump with the increase of the Froude number and bubble length. The effect of pipe inclination on characteristics of bubble is significant: The bubble is inversely located in a downwardly inclined pipe when the Froude number is low, and the transition from plug flow to slug flow in an upward inclined pipe is more ready to occur compared with that in a downwardly inclined pipe

  18. Intermittent cathodic protection for steel reinforced concrete bridges

    Energy Technology Data Exchange (ETDEWEB)

    Bullard, Sophie J.; Ziomek-Moroz, Margaret; Cramer, Stephen D.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Russell, James H.; Soltesz, S.M. (ODOT)

    2002-01-01

    Thermal-sprayed zinc anodes are used for impressed current cathodic protection (ICCP) systems on Oregon's reinforced concrete coastal bridges to prevent chloride-induced corrosion damage. Thermal-sprayed zinc performs well as an ICCP anode but the service life of the zinc anode is directly related to the average current density used to operate the systems. After a ICCP system is turned off, the rebar in the concrete remains passive and protected for a period of time. Intermittent operation of CP systems is possible when continuous corrosion rate monitoring is used to identify conditions when the CP system needs to be turned on to reestablish protection conditions for the rebar. This approach applies CP protection only when needed and reflects the fact that external protection may not be needed for a range of environmental conditions. In doing so, intermittent CP would lower the average current necessary to protect rebar, increase the anode service life, and reduce the lifetime costs for protecting reinforced concrete bridges.

  19. Tracking Intermittently Speaking Multiple Speakers Using a Particle Filter

    Directory of Open Access Journals (Sweden)

    Quinlan Angela

    2009-01-01

    Full Text Available The problem of tracking multiple intermittently speaking speakers is difficult as some distinct problems must be addressed. The number of active speakers must be estimated, these active speakers must be identified, and the locations of all speakers including inactive speakers must be tracked. In this paper we propose a method for tracking intermittently speaking multiple speakers using a particle filter. In the proposed algorithm the number of active speakers is firstly estimated based on the Exponential Fitting Test (EFT, a source number estimation technique which we have proposed. The locations of the speakers are then tracked using a particle filtering framework within which the decomposed likelihood is used in order to decouple the observed audio signal and associate each element of the decomposed signal with an active speaker. The tracking accuracy is then further improved by the inclusion of a silence region detection step and estimation of the noise-only covariance matrix. The method was evaluated using live recordings of 3 speakers and the results show that the method produces highly accurate tracking results.

  20. Timing of synchronization in intermittent irradiation synchronized with respiratory motion

    International Nuclear Information System (INIS)

    In order to reduce the increase in the irradiated volume caused by respiratory motion, a system which intermittently emits radiation synchronized with respiration was developed. A phantom of oscillating motion was made, and the effect of the motion on the penumbra of the dose profile was investigated by changing the distance of the motion and the timing of the synchronization. Irradiation was carried out by a 10-MV linear accelerator. Decreasing the irradiated time per motion cycle reduced the width of the penumbra. With a synchronized irradiation gated at end-of-inspiration or end-of-expiration, an intermittent irradiation ratio 47% kept the extension of the penumbra width to 2.2 times of the value measured in the phantom without motion when the motion distance was 4 cm. Investigation of the patients' diaphragmatic motion was done by reading the IBS (Image Brightness Stabilizer) circuit during fluoroscopic examination. A quiescent period was often observed at end-of-expiration. Synchronized irradiation gated at end-of-expiration was considered suitable for clinical application. (author)

  1. Associação entre a antropometria e a leptina circulante nos compartimentos materno, fetal e placentário, na gravidez normal Association between anthropometry and circulating leptin in maternal, fetal and placental compartments, in healthy pregnancy

    Directory of Open Access Journals (Sweden)

    Flávia Cipriano Castro

    2004-10-01

    Full Text Available OBJETIVO: avaliar a importância da leptina materna e fetal circulantes na gestação saudável por meio da avaliação de sua associação com variáveis antropométricas materna, placentária e fetal ao nascimento e as relações entre os compartimentos avaliados. MÉTODOS: em estudo transversal foi incluída amostra de 33 gestações únicas, a termo, com fetos saudáveis. As variáveis avaliadas foram idade materna, peso materno, índice de massa corporal, peso do recém-nascido, peso placentário e índice placentário. Amostras de sangue materno foram obtidas imediatamente antes do parto e em sangue do cordão umbilical ao nascimento. A dosagem da leptina sérica foi realizada por meio de radioimunoensaio convencional. As relações entre as concentrações de leptina sérica materna e da artéria e veia umbilicais com as variáveis de estudo foram verificadas através da regressão linear. RESULTADOS: a leptina foi detectada no sangue de todas as 33 gestantes e seus respectivos recém-nascidos, sendo a concentração no sangue materno (17,1±1,77 ng/ml superior à dos vasos umbilicais (veia 9,0±1,16 ng/mL; artéria 8,2±1,02 ng/mL, pPURPOSE: to evaluate the importance of circulating maternal and fetal leptin in the healthy gestation, using its association with maternal, placental and fetal anthropometric variables, obtained at birth, and the relationship between the evaluated compartments. METHODS: in a transversal study a population of 33 single, healthy and term gestations was studied. The evaluated variables were maternal age, maternal weight, body mass index (BMF, weight of the newborn, placental weight, and placental index. Samples of maternal blood were immediately obtained before birth and from fetal umbilical cord blood at birth. Determination of serum leptin was performed using conventional radioimmunoassay. The relationships between serum leptin concentrations in maternal blood, umbilical artery and vein and the studied variables were assessed through linear regression. RESULTS: leptin levels were detected in the blood of all 33 pregnant women and their respective newborns, with maternal blood concentration (17.1±1.77 ng/mL higher than that of umbilical vessels (vein: 9.0±1.16 ng/mL; artery: 8.23±1.02 ng/mL, p<0.0001. Leptin concentrations in the maternal blood were correlated with leptin concentrations in fetal blood (artery: coef. 0.63, p=0.037; vein: coef. 0.72, p=0.006. Regarding the anthropometric variables, leptin measured in the maternal blood was associated with initial and final maternal BMF (coef. 1.13; p=0.002; coef. 1,18, p=0.001 and cord leptin levels were correlated with the fetal weight at birth (vein: coef. 0.007, p=0.02; artery: coef. 0.006, p=0.02. CONCLUSION: there was a correlation between maternal and fetal leptin production and probably by the action of similar stimuli during gestation. Serum leptin was associated with the weight of the compartment where it circulates.

  2. Vínculo materno-fetal: implicaciones en el desarrollo psicológico y propuesta de intervención en atención temprana (Maternal-foetal bonding: implications for psychological development and proposal for early intervention

    Directory of Open Access Journals (Sweden)

    Claudia Patricia Roncallo

    2015-09-01

    Full Text Available Health research has identified maternal-foetal bonding as a significant antecedent of post-natal bonding between mother and baby. Maternal-foetal bonding is associated with the emotional and cognitive aspects that allow the foetus to be recreated as another human being. This bond is expressed in health practices aimed at the protection and welfare of the foetus. It has been observed that the psychological state of the mother affects the foetus at the neurobehavioral level and influences the appearance of developmental disorders that also manifest in the post-natal period, thereby significantly affecting the mother-baby relationship. Thus, early intervention practices could be extended to the prenatal period as a prevention strategy to favourably impact the health of the child and mother. To address this issue, we present an interdisciplinary intervention model, which focuses on maternal-foetal bonding as a protective factor for bonding during the postnatal period, and as an enhancer of positive parenting practices that promote healthy psychological development.

  3. Chronic intussusception in children caused by Ascaris lumbricoides.

    Science.gov (United States)

    Nikolić, Harry; Palčevski, Goran; Saina, Giordano; Peršić, Mladen

    2011-05-01

    Chronic intussusception (CI) is defined as an intussusception lasting for 14 days or more. Because the clinical manifestations are non-specific, the diagnosis is usually delayed. Symptoms include intermittent abdominal pain, sometimes an abdominal mass is palpable and there is a marked weight loss. Diagnosis is based on typical features revealed by ultrasound or barium enema and CT investigations. Therapy is surgical with obligatory exclusion of possible underlying lesions. We report a case of a 3.5-year-old girl with chronic intussusception. Laboratory blood findings revealed sideropenic anemia and stools positive for Ascaris lumbricoides. Anti-parasitic therapy with mebendazole was repeatedly administered with early improvements but soon after symptoms relapsed. During surgery an ileocolic chronic intussusception extending to hepatic flexure was found. Postoperative control examinations proved complete healing. We suspected that Ascaris lumbricoides infestation was an etiologic factor for the development of chronic intussusception in the child.

  4. Hippocampal impairments are associated with intermittent hypoxia of obstructive sleep apnea

    Institute of Scientific and Technical Information of China (English)

    FENG Jing; WU Qi; ZHANG Dan; CHEN Bao-yuan

    2012-01-01

    Obstructive sleep apnea (OSA),which is the most common sleep-related breathing disorder,is characterized as frequent upper airway collapse and obstruction.It is a treatable disorder but if left untreated is associated with complications in several organ systems.The health risk to OSA patients shows a strong association with acute cardiovascular events,and with chronic conditions.To the central nervous system,OSA causes behavioral and neuropsychologic deficits including daytime sleepiness,depression,impaired memory,mood disorders,cognition deficiencies,language comprehension and expression deficiencies,all of which are compatible with impaired hippocampal function.Furthermore,there exists a significant correlation between disease severity and cognitive deficits in OSA.Children with severe OSA have significantly lower intelligence quotient (IQ) and executive control functions compared to normal children matched for age,gender and ethnicity.This corroborates the findings of several pediatric studies of cognition in childhood OSA,where deficits are reported in general intelligence and some measures of executive function.In studies of OSA,it is difficult to differentiate the effects of its two main pathologic traits,intermittent hypoxia (IH) and sleep fragmentation.Many OSA studies,utilize IH as the only exposure factor in OSA studies.These approaches simplify research process and attain most of the academic goals.IH,continuous hypoxia and intermittent continuous hypoxia can all result in decreases in arterial O2.There are striking differences to them in the response of physiological systems.There are multiple studies showing that IH treatment in a rodent model of OSA can impair performance of standard water maze tests associated with deficits in spatial learning and memory which most likely are hippocampal-dependent.Cellular damage to the hippocampal cornuammonis 1 (CA1) region likely contributes to neuropsychological impairment among OSA patients,since neural circuits

  5. Continuous versus intermittent tamoxifen versus intermittent/alternated tamoxifen and medroxyprogesterone acetate as first line endocrine treatment in advanced breast cancer : An EORTC phase III study (10863)

    NARCIS (Netherlands)

    Beex, L.; Rose, C.; Mouridsen, H.; Jassem, J.; Nooij, M.; Estape, J.; Paridaens, R.; Piccart, M.; Gorlia, T.; Lardenoije, S.; Baila, L.

    2006-01-01

    Background: Continuous ligand depletion of endocrine responsive tumours may enhance resistance to therapy. Intermittent treatment with tamoxifen (T) was considered to mimic (incomplete) ligand depletion and reintroduction. Furthermore it was postulated that alternating tamoxifen with a non-cross res

  6. Continuous versus intermittent tamoxifen versus intermittent/alternated tamoxifen and medroxyprogesterone acetate as first line endocrine treatment in advanced breast cancer: an EORTC phase III study (10863).

    NARCIS (Netherlands)

    Beex, L.V.A.M.; Rose, C.; Mouridsen, H.; Jassem, J.; Nooij, M.; Estape, J.; Paridaens, R.; Piccart, M.; Gorlia, T.; Lardenoije, S.; Baila, L.

    2006-01-01

    BACKGROUND: Continuous ligand depletion of endocrine responsive tumours may enhance resistance to therapy. Intermittent treatment with tamoxifen (T) was considered to mimic (incomplete) ligand depletion and reintroduction. Furthermore it was postulated that alternating tamoxifen with a non-cross res

  7. Chronic pain - resources

    Science.gov (United States)

    Pain - resources; Resources - chronic pain ... The following organizations are good resources for information on chronic pain: American Chronic Pain Association -- www.theacpa.org National Fibromyalgia and Chronic Pain Association -- www.fmcpaware.org ...

  8. Low back pain - chronic

    Science.gov (United States)

    Nonspecific back pain; Backache - chronic; Lumbar pain - chronic; Pain - back - chronic; Chronic back pain - low ... Low back pain is common. Almost everyone has back pain at some time in their life. Often, the exact cause ...

  9. Chronic motor tic disorder

    Science.gov (United States)

    Chronic vocal tic disorder; Tic - chronic motor tic disorder ... Chronic motor tic disorder is more common than Tourette syndrome . Chronic tics may be forms of Tourette syndrome. Tics usually start ...

  10. Chronic Pelvic Pain

    Science.gov (United States)

    ... Events Advocacy For Patients About ACOG Chronic Pelvic Pain Home For Patients Search FAQs Chronic Pelvic Pain ... Pain FAQ099, August 2011 PDF Format Chronic Pelvic Pain Gynecologic Problems What is chronic pelvic pain? What ...

  11. Employees with Chronic Pain

    Science.gov (United States)

    ... Home | Accommodation and Compliance Series: Employees with Chronic Pain By Beth Loy, Ph.D. Preface Introduction Information ... at http://AskJAN.org/soar. Information about Chronic Pain How prevalent is chronic pain? Chronic pain has ...

  12. An investigation of apparent, intermittent fuel failure in TRIGA fuel

    International Nuclear Information System (INIS)

    Full text: The 1 Mw TRIGA Reactor is cooled by natural convection and 16N and 41Ar which were released from the pool caused an undesirably high background in the gas detector used for fission product monitorings. It was necessary to convert the gas detector which was very sensitive to 16N and 41Ar to a particulate monitor. The monitor chosen was a commercially available moving tape continuous air monitor. It was placed adjacent to the pool wall where air under the reactor bridge could be sampled at the surface of the pool water. This monitoring system proved to be adequate under normal conditions. However, on several occasions, sharp increases in activity of short, duration were noted on the monitor recorder. These brief high levels of activity were similar to those described by other facilities which had experienced intermittent fuel element leakage and the integrity of the reactor fuel was suspected. The filter paper from the monitor was removed and its gamma spectrum obtained using a 30 cc Ge(Li) detector. This analysis revealed only the naturally occurring airborne isotopes, and it was concluded that the recorder increases in activity were not from fuel leakage. It was suspected that the activity increases were due to the intermittent release of radioactive gases from the pool water at higher temperatures. A series of experiments was performed which demonstrated the following: 1. At pool temperatures up to 80oF, the reading of the CAM remained constant. From 80 to 95oF, the reading increased by nearly a factor of 3 and became more erratic. 2. With the air pump off, the CAM response did not change. 3. A gas monitor set up in series with the CAM exhibited nearly an identical response and its spectrum showed only the existence of 41Ar and 16N. 4. After reactor shutdown, the CAM reading decayed with a half-life of 1.4 hr. It was concluded that at the higher pool temperatures large bubbles containing 41Ar escaped to the pool surface and the 41Ar was seen through the

  13. Simultaneous Infrared Dry-Blanching and Dehydration of apple slices Controlled by Intermittent Heating Mode

    Science.gov (United States)

    Infrared heating controlled by intermittent heating mode was found to be able to achieve simultaneous dry-blanching and dehydration of apple slices with a desirable quality. In order to better understand the performance of intermittent heating for simultaneous dry-blanching and dehydration (SIDBD),...

  14. Intermittent turbulence and oscillations in the stable boundary layer over land

    NARCIS (Netherlands)

    Wiel, van de B.J.H.

    2002-01-01

    As the title of this thesis indicates, our main subject of interest is: "Intermittent turbulence and oscillation in the stable boundary layer over land". As such, this theme connects the different chapters. Here, intermittent turbulence is defined as a sequence of events were 'burst' of increased tu

  15. 29 CFR 825.203 - Scheduling of intermittent or reduced schedule leave.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Scheduling of intermittent or reduced schedule leave. 825.203 Section 825.203 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT... Family and Medical Leave Act § 825.203 Scheduling of intermittent or reduced schedule leave....

  16. Persistence during Extinction: Examining the Effects of Continuous and Intermittent Reinforcement on Problem Behavior

    OpenAIRE

    MacDonald, Jacquelyn M.; Ahearn, William H; Parry-Cruwys, Diana; Bancroft, Stacie; Dube, William V.

    2013-01-01

    This study examined behavioral persistence during extinction following continuous or intermittent reinforcement in the context of an analogue functional analysis of problem behavior. Participants were four children diagnosed with an autism spectrum disorder who engaged in problem behavior; and for whom functional analyses indicated sensitivity to social reinforcers. Experimental sessions included four successive 5-min components: No social interaction, continuous or intermittent reinforcement...

  17. The influence of basketball dribbling on repeated high-intensity intermittent runs

    Directory of Open Access Journals (Sweden)

    Zhaowei Kong

    2015-12-01

    Conclusion: The results suggest that the Yo-Yo IE2 test could reflect the repeatability of high-intensity intermittent basketball dribbling performance, while dribbling skills may have different influences on high-intensity intermittent exercise capacity in adolescent players at different ages.

  18. Chronic coughing

    International Nuclear Information System (INIS)

    Chronic coughing was acknowledged to result from pathological state of the respiratory organs. Cardiac diseases could be accompanied by coughing as well. It was recommended to perform x-ray examinations, including biomedical radiography of the chest, computerized tomography, scintiscanning with 67Ga-citrate, bronchi examination in order to exclude heart disease. The complex examination permitted to detect localization and type of the changes in the lungs and mediastinum, to distinguish benign tumor from malignant one

  19. Robust, low-cost data loggers for stream temperature, flow intermittency, and relative conductivity monitoring

    Science.gov (United States)

    Chapin, Thomas; Todd, Andrew S.; Zeigler, Matthew P.

    2014-01-01

    Water temperature and streamflow intermittency are critical parameters influencing aquatic ecosystem health. Low-cost temperature loggers have made continuous water temperature monitoring relatively simple but determining streamflow timing and intermittency using temperature data alone requires significant and subjective data interpretation. Electrical resistance (ER) sensors have recently been developed to overcome the major limitations of temperature-based methods for the assessment of streamflow intermittency. This technical note introduces the STIC (Stream Temperature, Intermittency, and Conductivity logger); a robust, low-cost, simple to build instrument that provides long-duration, high-resolution monitoring of both relative conductivity (RC) and temperature. Simultaneously collected temperature and RC data provide unambiguous water temperature and streamflow intermittency information that is crucial for monitoring aquatic ecosystem health and assessing regulatory compliance. With proper calibration, the STIC relative conductivity data can be used to monitor specific conductivity.

  20. Coexistence of intermittencies in the neuronal network of the epileptic brain

    Science.gov (United States)

    Koronovskii, Alexey A.; Hramov, Alexander E.; Grubov, Vadim V.; Moskalenko, Olga I.; Sitnikova, Evgenia; Pavlov, Alexey N.

    2016-03-01

    Intermittent behavior occurs widely in nature. At present, several types of intermittencies are known and well-studied. However, consideration of intermittency has usually been limited to the analysis of cases when only one certain type of intermittency takes place. In this paper, we report on the temporal behavior of the complex neuronal network in the epileptic brain, when two types of intermittent behavior coexist and alternate with each other. We prove the presence of this phenomenon in physiological experiments with WAG/Rij rats being the model living system of absence epilepsy. In our paper, the deduced theoretical law for distributions of the lengths of laminar phases prescribing the power law with a degree of -2 agrees well with the experimental neurophysiological data.

  1. Intermittent Fasting Modulation of the Diabetic Syndrome in Streptozotocin-Injected Rats

    Directory of Open Access Journals (Sweden)

    Louiza Belkacemi

    2012-01-01

    Full Text Available This study investigates the effects of intermittent overnight fasting in streptozotocin-induced diabetic rats (STZ rats. Over 30 days, groups of 5-6 control or STZ rats were allowed free food access, starved overnight, or exposed to a restricted food supply comparable to that ingested by the intermittently fasting animals. Intermittent fasting improved glucose tolerance, increased plasma insulin, and lowered Homeostatis Model Assessment index. Caloric restriction failed to cause such beneficial effects. The β-cell mass, as well as individual β-cell and islet area, was higher in intermittently fasting than in nonfasting STZ rats, whilst the percentage of apoptotic β-cells appeared lower in the former than latter STZ rats. In the calorie-restricted STZ rats, comparable findings were restricted to individual islet area and percentage of apoptotic cells. Hence, it is proposed that intermittent fasting could represent a possible approach to prevent or minimize disturbances of glucose homeostasis in human subjects.

  2. Effects of intermittent aeration on pollutants removal in subsurface wastewater infiltration system.

    Science.gov (United States)

    Pan, Jing; Fei, Hexin; Song, Siyu; Yuan, Fang; Yu, Long

    2015-09-01

    In this study, the pollutant removal performances in two pilot-scale subsurface wastewater infiltration systems (SWISs) with and without intermittent aeration were investigated. Matrix oxidation reduction potential (ORP) results showed that intermittent aeration well developed aerobic conditions in upper matrix and anoxic or anaerobic conditions in the subsequent sections, which resulted in high NH4(+)-N and TN removal. Moreover, intermittent aeration increased removal rates of COD and TP. Microbial populations and enzyme activities analysis proved that intermittent aeration not only obviously boosted the growth and reproduction of bacteria, fungus, actinomyces, nitrifying bacteria and denitrifying bacteria, but also successfully increased nitrate reductase (NR) and nitrite reductase (NIR) in the depth of 80 and 110 cm. The results suggest that the intermittent aeration could be a widespread research and application strategy for achieving the high removal performance in SWISs.

  3. Intermittency, nonlinear dynamics and dissipation in the solar wind and astrophysical plasmas.

    Science.gov (United States)

    Matthaeus, W H; Wan, Minping; Servidio, S; Greco, A; Osman, K T; Oughton, S; Dmitruk, P

    2015-05-13

    An overview is given of important properties of spatial and temporal intermittency, including evidence of its appearance in fluids, magnetofluids and plasmas, and its implications for understanding of heliospheric plasmas. Spatial intermittency is generally associated with formation of sharp gradients and coherent structures. The basic physics of structure generation is ideal, but when dissipation is present it is usually concentrated in regions of strong gradients. This essential feature of spatial intermittency in fluids has been shown recently to carry over to the realm of kinetic plasma, where the dissipation function is not known from first principles. Spatial structures produced in intermittent plasma influence dissipation, heating, and transport and acceleration of charged particles. Temporal intermittency can give rise to very long time correlations or a delayed approach to steady-state conditions, and has been associated with inverse cascade or quasi-inverse cascade systems, with possible implications for heliospheric prediction.

  4. Intermittency and chaos in intracavity doubled lasers. II

    Energy Technology Data Exchange (ETDEWEB)

    James, G.E.; Harrell, E.M. II (School of Mathematics, Georgia Institute of Technology, Atlanta, Georgia 30332 (USA)); Roy, R. (School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (USA))

    1990-03-01

    We describe the nonlinear dynamics of intracavity doubled multimode lasers. Baer (J. Opt. Soc. Am. B 3, 1175 (1986)) observed irregular amplitude fluctuations in a multimode yttrium aluminum garnet laser with an intracavity potassium titanyl phosphate frequency-doubling crystal; we identify type-III intermittency as the route to chaos. Subsequently, Oka and Kubota (Opt. Lett. 13, 805 (1988)) demonstrated the stabilization of such a laser by the introduction of a quarter wave plate into the cavity. A generalized model of rate equations for this case is introduced. It is shown that a second route to chaos through a Hopf bifurcation, synchronization, and period-doubling sequence occurs on rotation of the quarter wave plate within the cavity. In addition, we predict that the laser output may be stable for particular lengths of the doubling crystal.

  5. A conditional simulation model of intermittent rain fields

    Directory of Open Access Journals (Sweden)

    L. G. Lanza

    2000-01-01

    Full Text Available The synthetic generation of random fields with specified probability distribution, correlation structure and probability of no-rain areas is used as the basis for the formulation of a stochastic space-time rainfall model conditional on rain gauge observations. A new procedure for conditioning while preserving intermittence is developed to provide constraints to Monte Carlo realisations of possible rainfall scenarios. The method addresses the properties of the convolution operator involved in generating random field realisations and is actually independent of the numerical algorithm used for unconditional simulation. It requires only the solution of a linear system of algebraic equations the order of which is given by the number of the conditioning nodes. Applications of the methodology are expected in rainfall field reconstruction from sparse rain gauge data and in rainfall downscaling from the large scale information that may be provided by remote sensing devices or numerical weather prediction models. Keywords: Space-time rainfall; Conditioning; Stochastic models

  6. Detecting the temporal structure of intermittent phase locking

    CERN Document Server

    Ahn, Sungwoo; Rubchinsky, Leonid L

    2011-01-01

    This study explores a method to characterize temporal structure of intermittent phase locking in oscillatory systems. When an oscillatory system is in a weakly synchronized regime away from a synchronization threshold, it spends most of the time in parts of its phase space away from synchronization state. Therefore characteristics of dynamics near this state (such as its stability properties/Lyapunov exponents or distributions of the durations of synchronized episodes) do not describe system's dynamics for most of the time. We consider an approach to characterize the system dynamics in this case, by exploring the relationship between the phases on each cycle of oscillations. If some overall level of phase locking is present, one can quantify when and for how long phase locking is lost, and how the system returns back to the phase-locked state. We consider several examples to illustrate this approach: coupled skewed tent maps, which stability can be evaluated analytically, coupled R\\"{o}ssler and Lorenz oscill...

  7. Hyperchaotic Intermittent Convection in a Magnetized Viscous Fluid

    CERN Document Server

    Macek, Wieslaw M

    2014-01-01

    We consider a low-dimensional model of convection in a horizontally magnetized layer of a viscous fluid heated from below. We analyze in detail the stability of hydromagnetic convection for a wide range of two control parameters. Namely, when changing the initially applied temperature difference or magnetic field strength, one can see transitions from regular to irregular long-term behavior of the system, switching between chaotic, periodic, and equilibrium asymptotic solutions. It is worth noting that owing to the induced magnetic field a transition to hyperchaotic dynamics is possible for some parameters of the model. We also reveal new features of the generalized Lorenz model, including both type I and III intermittency.

  8. Turbulent energy dissipation and intermittency in ambipolar diffusion magnetohydrodynamics

    CERN Document Server

    Momferratos, Georgios; Falgarone, Edith; Forêts, Guillaume Pineau des

    2015-01-01

    The dissipation of kinetic and magnetic energy in the interstellar medium (ISM) can proceed through viscous, Ohmic or ambipolar diffusion (AD). It occurs at very small scales compared to the scales at which energy is presumed to be injected. This localized heating may impact the ISM evolution but also its chemistry, thus providing observable features. Here, we perform 3D spectral simulations of decaying magnetohydrodynamic turbulence including the effects of AD. We find that the AD heating power spectrum peaks at scales in the inertial range, due to a strong alignment of the magnetic and current vectors in the dissipative range. AD affects much greater scales than the AD scale predicted by dimensional analysis. We find that energy dissipation is highly concentrated on thin sheets. Its probability density function follows a lognormal law with a power-law tail which hints at intermittency, a property which we quantify by use of structure function exponents. Finally, we extract structures of high dissipation, de...

  9. Fractal clusters and intermittency in relativistic heavy ion collisions

    CERN Document Server

    Antoniou, Nikos G; Diakonos, F K

    2000-01-01

    We investigate the formation of particle clusters (pions) associated with the chiral QCD phase transition in thermodynamic equilibrium. The geometry of these clusters at the critical point (T=T/sub c/) turns out to be fractal reflecting the self similar structure of the density fluctuations of the produced pions. The fractal dimension of the "critical" clusters is related to the critical exponents characterizing the phase transition. We examine the possibility to observe such pion clusters in relativistic heavy ion collisions. A Monte Carlo simulation of the critical system in 3D is performed leading to a typical set of "critical" events. Factorial moment analysis of the rapidity and transverse momentum distribution for these events shows a characteristic intermittency pattern. Mini-jet like structures arise in a azimuth angle rapidity lego plot. These features allow for a unique identification of the class of "critical events" in an event by event analysis in current and future experiments with relativistic ...

  10. Modeling Integrated Water-User Decisions with Intermittent Supplies

    Science.gov (United States)

    Lund, J. R.; Rosenberg, D.

    2006-12-01

    We present an economic-engineering method to estimate urban water use demands with intermittent water supplies. A two-stage, probabilistic optimization formulation includes a wide variety of water supply enhancement and conservation actions that individual households can adopt to meet multiple water quality uses with uncertain water availability. We embed the optimization in Monte-Carlo simulations to show aggregate effects at a utility (citywide) scale for a population of user conditions and decisions. Parametric analysis provides derivations of supply curves to subsidize conservation, demand responses to alternative pricing, and customer willingness-to-pay to avoid shortages. Results show a good empirical fit for the average and distribution of billed residential water use in Amman, Jordan. Additional outputs give likely market penetration rates for household conservation actions, associated water savings, and subsidies required to entice further adoption. We discuss new insights to size, target, market, and finance conservation programs and interpret a demand curve with block pricing.

  11. Suppression of spiral waves using intermittent local electric shock

    Institute of Scientific and Technical Information of China (English)

    Ma Jun; Ying He-Ping; Li Yan-Long

    2007-01-01

    In this paper, an intermittent local electric shock scheme is proposed to suppress stable spiral waves in the Barkley model by a weak electric shock (about 0.4 to 0.7) imposed on a random selected n × n grids (n = 1-5, compared with the original 256×256 lattice) and monitored synchronically the evolutions of the activator on the grids as the sampled signal of the activator steps out a given threshold (i.e., the electric shock works on the n × n grids if the activator u (≤) 0.4 or u (≥) 0.8). The numerical simulations show that a breakup of spiral is observed in the media state evolution to finally obtain homogeneous states if the electric shock with appropriate intensity is imposed.

  12. Wind and Current Intermittency in Coastal and Atmospheric Environments

    Science.gov (United States)

    Sekula, Emil; Martinez-Benjamin, Juan Jose; Redondo, Jose M.; Jorge, Juan; Mahjoub, Otman B.

    2015-04-01

    We study at several non-homogeneous sites, such as the coastal Mediterranean Area (Ebro Delta, Blanes) and in the iberian Plateau the wind intermittency as well as the fractal structure of the induced cloud and wave fronts. Weather data from 10 and 100m hight masts are used to calculate Local Richardson number, Monin-Obukhov length, eddy transfer coefficients, turbulent kinetic energy, turbulent intensities, friction velocities and sensible heat flux at three levels (5, 17 and 32 m) were considered. The results show how the stability at 17 and 32 m influences the turbulent transfer near the ground. The shear of wind or convection are the main mechanism to produce mixing in the surface, which is often detected in satellite images of nearby clouds or coastal features. The influence of internal gravity-waves on the atmospheric boundary-layer during strong stable stratification is quantified. atmospheric and oceanic circulation involve non-linear intermittency that account for unresolved turbulent mixing and diffusion. The most sophisticated turbulent closure models involve using structure functions of higher order [1,2]. The relationship between the intermittency of turbulence and the type of stratification for different atmospheric situations during the SABLES98 field campaign. We first show that the scaling behaviour of the velocity structure function in events such as GABLS (GEWEX Atmospheric Boundary-Layer Study)and in combined ESA SAR measurements [3-6] near the coast exhibit fractal and intermittent scaling. Near the Gulf of Lyons, vortical scaling show coupling between synoptic and rossby deformation scales [7]. [1]Mahjoub O., Redondo J.M. and Babiano A. (1998) Structure Functions in Complex Flows, Applied Scientific Research 59, 299-313. [2]Fraunie P., Berreba S. Chashechkin Y., Velasco D. and Redondo J.M. (2008)LES and laboratory experiments on the decay of grid wakes in strongly stratified flows. Il Nuovo Cimento C 31, 909-930. [3]Diez M., Bezerra M

  13. Intermittent Jolts of Galactic UV Radiation Mutagenetic Effects

    CERN Document Server

    Scalo, J M; Williams, P; Scalo, John M.; Williams, Peter

    2001-01-01

    We estimate the frequency of intermittent hypermutation events and disruptions of planetary/satellite photochemistry due to ultraviolet radiation from core collapse supernova explosions. Calculations are presented for planetary systems in the local Milky Way, including the important moderating effects of vertical Galactic structure and UV absorption by interstellar dust. The events are particularly frequent for satellites of giant gas planets at \\gtrsim 5-10 AU distance from solar-type parent stars, or in the conventional habitable zones for planets orbiting spectral type K and M parent stars, with rates of significant jolts about 10^3 - 10^4 per Gyr. The steep source spectra and existing data on UVA and longer-wavelength radiation damage in terrestrial organisms suggest that the mutational effects may operate even on planets with ozone shields. We argue that the mutation doubling dose for UV radiation should be much smaller than the mean lethal dose, using terrestrial prokaryotic organisms as our model, and ...

  14. Caustics and Intermittency in Turbulent Suspensions of Heavy Particles

    CERN Document Server

    Bec, J; Cencini, M; Lanotte, A S; Toschi, F

    2009-01-01

    The statistics of velocity differences between very heavy inertial particles suspended in an incompressible turbulent flow is found to be extremely intermittent. When particles are separated by distances within the viscous subrange, the competition between quiet regular regions and multi-valued caustics leads to a quasi bi-fractal behavior of the particle velocity structure functions, with high-order moments bringing the statistical signature of caustics. Contrastingly, for particles separated by inertial-range distances, the velocity-difference statistics is characterized in terms of a local H\\"{o}lder exponent, which is a function of the scale-dependent particle Stokes number only. Results are supported by high-resolution direct numerical simulations. It is argued that these findings might have implications in the early stage of rain droplets formation in warm clouds.

  15. Intermittency and transient chaos from simple frequency-dependent selection.

    Science.gov (United States)

    Gavrilets, S; Hastings, A

    1995-08-22

    Frequency-dependent selection is an important determinant of the evolution of gametophytic self-incompatibility systems in plants, aposematic (warning) and cryptic coloration, systems of mimicry, competitive interactions among members of a population, mating preferences, predator-prey and host-parasite interactions, aggression and other behavioural traits. Past theoretical studies of frequency-dependent selection have shown it to be a plausible mechanism for the maintenance of genetic variability in natural populations. Here, through an analysis of a simple deterministic model for frequency-dependent selection, we demonstrate that complex dynamic behaviour is possible under a broad range of parameter values. In particular we show that the model exhibits not only cycles and chaos but also, for a more restricted set of parameters, transient chaos and intermittency: alterations between an apparently deterministic behaviour and apparently chaotic fluctuations. This behaviour, which has not been stressed within the population genetics literature, provides an explanation for erratic dynamics of gene frequencies.

  16. Intermittent Flow of Granular Matter in an Annular Geometry

    Science.gov (United States)

    Brzinski, Ted; Daniels, Karen E.

    Granular solids can be subjected to a finite stress below which the response is elastic. Above this yield stress, however, the material fails catastrophically, undergoing a rapid plastic deformation. In the case of a monotonically increasing stress the material exhibits a characteristic stick-slip response. We investigate the statistics of this intermittent failure in an annular shear geometry, driven with a linear-ramp torque in order to generate the stick-slip behavior. The apparatus is designed to allow visual access to particle trajectories and inter-particle forces (through the use of photoelastic materials). Additionally, twelve piezoelectric sensors at the outer wall measure acoustic emissions due to the plastic deformation of the material. We vary volume fraction, and use both fixed and deformable boundaries. We measure how the distribution of slip size and duration are related to the bulk properties of the packing, and compare to systems with similar governing statistics.

  17. Optimizing intermittent water supply in urban pipe distribution networks

    CERN Document Server

    Lieb, Anna M; Wilkening, Jon

    2015-01-01

    In many urban areas of the developing world, piped water is supplied only intermittently, as valves direct water to different parts of the water distribution system at different times. The flow is transient, and may transition between free-surface and pressurized, resulting in complex dynamical features with important consequences for water suppliers and users. Here, we develop a computational model of transition, transient pipe flow in a network, accounting for a wide variety of realistic boundary conditions. We validate the model against several published data sets, and demonstrate its use on a real pipe network. The model is extended to consider several optimization problems motivated by realistic scenarios. We demonstrate how to infer water flow in a small pipe network from a single pressure sensor, and show how to control water inflow to minimize damaging pressure gradients.

  18. Optimal control system of the intermittent bus-only approach

    Institute of Scientific and Technical Information of China (English)

    Jie Jiang; Yulin Chang

    2014-01-01

    To guarantee bus priority with a minimum impact on car traffic at intersections, an optimal control system of the intermittent bus-only approach (IBA) was proposed. The problems of the existing system are first solved through optimization: the judgment time of the IBA system was advanced to allow a bus to jump car queues if the bus was detected to arrive at the intersection, and the instant that the IBA lane became available to cars was controlled dynamically to increase the capacity of the IBA lane. The total car delay in one cycle was then analyzed quantitatively when implementing the optimal control system. The results show that in comparison with the existing system of the IBA, the car delay is greatly reduced and the probability of a car stopping twice is low after optimizing the IBA system.

  19. BCR Routing for Intermittently Connected Mobile Ad hoc Networks

    Directory of Open Access Journals (Sweden)

    S. RAMESH

    2014-03-01

    Full Text Available The Wireless and the Mobile Networks appear to provide a wide range of applications. Following these, the Mobile Ad hoc Networks (MANET aid in wide development of many applications. The achievement of the real world applications are attained through effective routing. The Intermittently Connected Mobile Ad hoc Network (ICMANET is a sparse network where a full connectivity is never possible. ICMANET is a disconnected MANET and is also a Delay Tolerant Network (DTN that sustains for higher delays. The routing in a disseminated network is a difficult task. A new routing scheme called Bee Colony Routing (BCR is been proposed with a motto of achieving optimal result in delivering the data packet towards the destined node. BCR is proposed with the basis of Bee Colony Optimization technique (BCO. The routing in ICMNAET is done by means of Bee routing protocol. This paper enchants a novel routing methodology for data transmission in ICMANET.

  20. Acute intermittent porphyria: A critical diagnosis for favorable outcome.

    Science.gov (United States)

    Divecha, Chhaya; Tullu, Milind S; Gandhi, Akanksha; Deshmukh, Chandrahas T

    2016-07-01

    Acute intermittent porphyria (AIP) is an inherited metabolic disorder characterized by the accumulation of toxic metabolites of the heme pathway. It rarely presents in the prepubertal age group. AIP often presents with nonspecific and nonlocalizing symptoms. Moreover, several commonly used medications and stress states are known to precipitate an attack. We present the case of a previously healthy 5 years female who was diagnosed as acute central nervous system infection/inflammation at admission. It was the presence of red flags that led to a correct diagnosis. Besides supportive management, a dedicated search for intravenous hemin (chemically heme arginate, aminolevulinic acid synthase inhibitor, and drug of choice) was attempted. Unexpected help was rendered by doctors from a medical college in Gujarat, and two ampoules could be obtained. The patient received three doses of intravenous hemin; however, she succumbed later. This case is presented for the diagnostic and therapeutic challenges faced in developing countries. PMID:27555700

  1. Distributed Particle Filter Implementation with Intermittent/Irregular Consensus Convergence

    CERN Document Server

    Mohammadi, Arash

    2011-01-01

    Motivated by non-linear, non-Gaussian, distributed multi-sensor/agent navigation and tracking applications, we propose a multi-rate consensus/fusion based framework for distributed implementation of the particle filter (CF/DPF). The CF/DPF framework is based on running localized particle filters to estimate the overall state vector at each observation node. Separate fusion filters are designed to consistently assimilate the local filtering distributions into the global posterior by compensating for the common past information between neighbouring nodes. The CF/DPF offers two distinct advantages over its counterparts. First, the CF/DPF framework is suitable for scenarios where network connectivity is intermittent and consensus can not be reached between two consecutive observations. Second, the CF/DPF is not limited to the Gaussian approximation for the global posterior density. A third contribution of the paper is the derivation of the optimal posterior Cram\\'er-Rao lower bound (PCRLB) for the distributed arc...

  2. Intermittent criticality on a regional scale in Bhuj

    Science.gov (United States)

    Padhy, Simanchal

    2004-08-01

    The statistics of the Bhuj earthquake population are examined to investigate the proximity of the system to the critical state, defined through an entropy-energy relationship based on the tools of statistical mechanics. The results are compared with a theoretical model corresponding to a Boltzmann probability density distribution of degenerate microscopic energy states of the form p(E) ~E-B-1 e-E/θ. The data exhibit fluctuations in characteristic energy θ at a constant B-value of the form S~B. Features such as (1) time-dependent variations in seismicity during the period of presumably uncorrelated stress field following a major event, and (2) +/-12 per cent fluctuations in the macroscopic thermodynamic variable (entropy) support the intermittent criticality of Bhuj crust.

  3. Intermittent Testing and Training for High-Level Football Players

    DEFF Research Database (Denmark)

    Ingebrigtsen, Jørgen

    Football is the most popular sport in the world, played by over 400 million men and women. In addition to the wide range of sport-specific technical and tactical skills needed, several physical components have been shown to be necessary to perform at a high level. The present PhD thesis is based...... on four articles that focus on physical testing and training for elite and sub-elite football players.The first article (Study I) aims to identify and establish aerobic capacities and anthropometric characteristics of elite female football players with the use of laboratory tests, and to examine whether...... systematic differences between the playing positions can be detected. Lately, field tests have become more frequently used in football than the laboratory tests used in Study I. Study II therefore aims to assess the validity of one of them, the Yo-Yo Intermittent Recovery test level 2 (Yo-Yo IR2). Along...

  4. Intermittent Noise Induces Physiological Stress in a Coastal Marine Fish.

    Directory of Open Access Journals (Sweden)

    Tye A Nichols

    Full Text Available Anthropogenic noise in the ocean has increased substantially in recent decades, and motorized vessels produce what is likely the most common form of underwater noise pollution. Noise has the potential to induce physiological stress in marine fishes, which may have negative ecological consequences. In this study, physiological effects of increased noise (playback of boat noise recorded in the field on a coastal marine fish (the giant kelpfish, Heterostichus rostratus were investigated by measuring the stress responses (cortisol concentration of fish to increased noise of various temporal dynamics and noise levels. Giant kelpfish exhibited acute stress responses when exposed to intermittent noise, but not to continuous noise or control conditions (playback of recorded natural ambient sound. These results suggest that variability in the acoustic environment may be more important than the period of noise exposure for inducing stress in a marine fish, and provide information regarding noise levels at which physiological responses occur.

  5. Intermittent Noise Induces Physiological Stress in a Coastal Marine Fish.

    Science.gov (United States)

    Nichols, Tye A; Anderson, Todd W; Širović, Ana

    2015-01-01

    Anthropogenic noise in the ocean has increased substantially in recent decades, and motorized vessels produce what is likely the most common form of underwater noise pollution. Noise has the potential to induce physiological stress in marine fishes, which may have negative ecological consequences. In this study, physiological effects of increased noise (playback of boat noise recorded in the field) on a coastal marine fish (the giant kelpfish, Heterostichus rostratus) were investigated by measuring the stress responses (cortisol concentration) of fish to increased noise of various temporal dynamics and noise levels. Giant kelpfish exhibited acute stress responses when exposed to intermittent noise, but not to continuous noise or control conditions (playback of recorded natural ambient sound). These results suggest that variability in the acoustic environment may be more important than the period of noise exposure for inducing stress in a marine fish, and provide information regarding noise levels at which physiological responses occur. PMID:26402068

  6. Liver transplantation for acute intermittent porphyria:a viable treatment?

    Institute of Scientific and Technical Information of China (English)

    Faisal S Dar; Koji Asai; Ali Raza Haque; Thomas Cherian; Mohamed Rela; Nigel Heaton

    2010-01-01

    BACKGROUND:Acute intermittent porphyria (AIP) is the most common hepatic porphyria. Its clinical presentation includes severe disabling and life-threatening neurovisceral symptoms and acute psychiatric symptoms. These symptoms result from the overproduction and accumulation of porphyrin precursors, 5-aminoleuvulinic acid (ALA) and porphobilinogen (PBG). The effect of medical treatment is transient and is not effective once irreversible neurological damage has occurred. Liver transplantation (LT) replaces hepatic enzymes and can restore normal excretion of ALA and PBG and prevent acute attacks. METHOD:Two cases of LT for AIP were identiifed retro-spectively from a prospectively maintained LT database. RESULT:LT was successful with resolution of AIP in two patients who suffered from repeated acute attacks. CONCLUSION:LT can correct the underlying metabolic abnormality in AIP and improves quality of life signiifcantly.

  7. ImOSM: intermittent evolution and robustness of phylogenetic methods.

    Science.gov (United States)

    Thi Nguyen, Minh Anh; Gesell, Tanja; von Haeseler, Arndt

    2012-02-01

    Among the criteria to evaluate the performance of a phylogenetic method, robustness to model violation is of particular practical importance as complete a priori knowledge of evolutionary processes is typically unavailable. For studies of robustness in phylogenetic inference, a utility to add well-defined model violations to the simulated data would be helpful. We therefore introduce ImOSM, a tool to imbed intermittent evolution as model violation into an alignment. Intermittent evolution refers to extra substitutions occurring randomly on branches of a tree, thus changing alignment site patterns. This means that the extra substitutions are placed on the tree after the typical process of sequence evolution is completed. We then study the robustness of widely used phylogenetic methods: maximum likelihood (ML), maximum parsimony (MP), and a distance-based method (BIONJ) to various scenarios of model violation. Violation of rates across sites (RaS) heterogeneity and simultaneous violation of RaS and the transition/transversion ratio on two nonadjacent external branches hinder all the methods recovery of the true topology for a four-taxon tree. For an eight-taxon balanced tree, the violations cause each of the three methods to infer a different topology. Both ML and MP fail, whereas BIONJ, which calculates the distances based on the ML estimated parameters, reconstructs the true tree. Finally, we report that a test of model homogeneity and goodness of fit tests have enough power to detect such model violations. The outcome of the tests can help to actually gain confidence in the inferred trees. Therefore, we recommend using these tests in practical phylogenetic analyses.

  8. INTERMITTENT VERSUS CONTINUOUS INCREMENTAL FIELD TESTS: ARE MAXIMAL VARIABLES INTERCHANGEABLE?

    Directory of Open Access Journals (Sweden)

    Lorival J. Carminatti

    2013-03-01

    Full Text Available The aim of the present study was to compare physiological responses derived from an incremental progressive field test with a constant speed test i.e. intermittent versus continuous protocol. Two progressive maximum tests (Carminatti`s test (T-CAR and the Vameval test (T-VAM, characterized by increasing speed were used. T-CAR is an intermittent incremental test, performed as shuttle runs; while T-VAM is a continuous incremental test performed on an athletic track. Eighteen physically active, healthy young subjects (21.9 ± 2.0 years; 76.5 ± 8.6 kg, 1.78 ± 0.08 m, 11.2 ± 5.4% body fat, volunteered for this study. Subjects performed four different maximum test sessions conducted in the field: two incremental tests and two time to exhaustion tests (TTE at peak test velocities (PV. No significant differences were found for PV (T-CAR = 15.6 ± 1.2; T-VAM = 15.5 ± 1.3 km·h-1 and maximal HR (T-CAR = 195 ± 11; T- VAM = 194 ± 14 bpm. During TTE, there were no significant differences for HR (TTET-CAR and TTET-VAM = 192 ± 12 bpm. However, there was a significant difference in TTE (p = 0.04 (TTET-CAR = 379 ± 84, TTET-VAM = 338 ± 58 s with a low correlation (r = 0.41. The blood lactate concentration measured at the end of the TTE tests, showed no significant difference (TTET-CAR = 13.2 ± 2.4 vs. TTET-VAM = 12.9 ± 2.4 mmol·l-1. Based on the present findings, it is suggested that the maximal variables derived from T-CAR and T-VAM can be interchangeable in the design of training programs.

  9. Shifts in striatal responsivity evoked by chronic stimulation of dopamine and glutamate systems.

    Science.gov (United States)

    Canales, J J; Capper-Loup, C; Hu, D; Choe, E S; Upadhyay, U; Graybiel, A M

    2002-10-01

    Dopamine and glutamate are key neurotransmitters in cortico-basal ganglia loops affecting motor and cognitive function. To examine functional convergence of dopamine and glutamate neurotransmitter systems in the basal ganglia, we evaluated the long-term effects of chronic stimulation of each of these systems on striatal responses to stimulation of the other. First we exposed rats to chronic intermittent cocaine and used early-gene assays to test the responsivity of the striatum to subsequent acute motor cortex stimulation by application of the GABA(A) (gamma-aminobutyric acid alpha subunit) receptor antagonist, picrotoxin. Reciprocally, we studied the effects of chronic intermittent motor cortex stimulation on the capacity for subsequent acute dopaminergic treatments to induce early-gene activation in the striatum. Prior treatment with chronic intermittent cocaine induced motor sensitization and significantly potentiated the striatal expression of Fos-family early genes in response to stimulation of the motor cortex. Contrary to this, chronic intermittent stimulation of the motor cortex down-regulated cocaine-induced gene expression in the striatum, but enhanced striatal gene expression induced by a full D1 receptor agonist (SKF 81297) and did not change the early-gene response elicited by a D2 receptor antagonist (haloperidol). These findings suggests that repeated dopaminergic stimulation produces long-term enhancement of corticostriatal signalling from the motor cortex, amplifying cortically evoked modulation of the basal ganglia. By contrast, persistent stimulation of the motor cortex inhibits cocaine-stimulated signalling in the striatum, but not signalling mediated by individual dopamine receptor sites, suggesting that chronic cortical hyperexcitability produces long-term impairment of dopaminergic activity and compensation at the receptor level. These findings prompt a model of the basal ganglia function as being regulated by opposing homeostatic dopamine

  10. Comparison Between the Continuous and Intermittent Heating Methods for Simultaneous Infrared Dry-Blanching and Dehydration of Apple Slices

    Science.gov (United States)

    Simultaneous infrared dry-blanching and dehydration (SIRDBD) can be operated in two heating modes, continuous and intermittent heating. Under continuous heating, infrared radiation intensity was kept constant while the product temperature remained constant under intermittent heating in this study. ...

  11. OBSERVATION ON THE THERAPEUTIC EFFECT OF ELECTROACUPUNCTURE TREATMENT FOR SIMPLE CHRONIC RHINITIS

    Institute of Scientific and Technical Information of China (English)

    WEN Biling; ZHOU Shuang; YANG Yihong

    2002-01-01

    @@ Simple chronic rhinitis is a reversible chronic inflammatory disorder of nasal mucosa caused by various factors, it is a frequently encountered disorder with clinical manifestations of increased nasal secretion, intermittent alternative nasal obstruction, frequent ( respiratory ) anosmia and rhinophonia while speaking. In severe cases, it may manifest as hypocathexis, hypomnesis, fatigue, headache, head distress, insomnia, etc.that considerably hinder the patient's work or study. In the last 10 years, the authors have chiefly applied electroacupuncture (EA) to treatment of 38 cases of chronic rhinitis and the therapeutic effects are satisfactory. The following is the report of the treatment.

  12. An Efficient Chronic Unpredictable Stress Protocol to Induce Stress-Related Responses in C57BL/6 Mice

    OpenAIRE

    Monteiro, Susana; Roque, Susana; de Sá-Calçada, Daniela; Sousa, Nuno; Correia-Neves, Margarida; Cerqueira, João José

    2015-01-01

    Exposure to chronic stress can have broad effects on health ranging from increased predisposition for neuropsychiatric disorders to deregulation of immune responses. The chronic unpredictable stress (CUS) protocol has been widely used to study the impact of stress exposure in several animal models and consists in the random, intermittent, and unpredictable exposure to a variety of stressors during several weeks. CUS has consistently been shown to induce behavioral and immunological alteration...

  13. Ecoulements intermittents de gaz et de liquide en conduite verticale Intermittent Gas and Liquid Flows in a Vertical Pipe.

    Directory of Open Access Journals (Sweden)

    Line A.

    2006-11-01

    Full Text Available Le modèle présenté ici permet la pré-détermination du gradient de pression, du taux global de gaz, et de grandeurs caractéristiques de l'intermittence, dans un écoulement à poches et bouchons en conduite verticale. L'écriture des lois de conservation en moyenne phasique conditionnelle conduit à la définition d'une cellule moyenne équivalente. La fermeture du modèle est assurée par des lois de contrainte de cisaillement film-paroi, film-poche, bouchon-paroi, par une loi d'arrachage du gaz au culot de la poche, une loi de glissement du gaz dans les bouchons et par une loi de la vitesse moyenne de propagation des fronts de poches. Le calibrage et la qualification du modèle s'appuient sur deux banques de données, dont l'une a été obtenue avec des fluides pétroliers dans des conditions proches des situations industrielles (boucle diphasique de Boussens. The model described here can be used to predetermine the pressure gradient, the overall gas rate and the characteristic intermittence magnitudes in pocket and slug flow in a vertical pipe. The way governing equations in the conditional phase average are written defines an equivalent average cell. The model is closed by film/wall, film/pocket and slug/wall shear-stress laws, by a pulloff law for the gas at the bottom of the pocket, a slippage law for the gas in the slugs, and a mean propagation velocity law for the pocket fronts. The calibration and qualification of the model are based on two data banks, one of which contains data on petroleum fluids under conditions close to industrial situations (two-phase loop at Boussens.

  14. Chronic Insomnia

    OpenAIRE

    Buysse, Daniel J.

    2008-01-01

    Ms. F, a 42-year-old divorced woman, presents for evaluation of chronic insomnia. She complains of difficulty falling asleep, often 30 minutes or longer, and difficulty maintaining sleep during the night, with frequent awakenings that often last 30 minutes or longer. These symptoms occur nearly every night, with only one or two “good” nights per month. She typically goes to bed around 10:00 p.m. to give herself adequate time for sleep, and she gets out of bed around 7:00 a.m. on work days and...

  15. Effects of the Intermittent Pneumatic Circulator on Blood Pressure during Hemodialysis

    Directory of Open Access Journals (Sweden)

    Miao-Ju Hsu

    2010-11-01

    Full Text Available Hypotension is frequently reported during hemodialysis. This study aimed to examine the effect of the intermittent pneumatic circulator on blood pressure during hemodialysis. Sixteen subjects with chronic hemodialysis were recruited. Each subject randomly received two test conditions on separate days, hemodialysis with and without the circulator. The circulator was applied to the subject on lower extremities during 0.5–1 hr, 1.5–2 hr, 2.5–3 hr, and 3.5–4 hr of hemodialysis. Systolic and diastolic blood pressures (SBP and DBP and heart rate (HR were analyzed at pre-dialysis, 1 hr, 2 hr, and 3 hr of hemodialysis. Stroke volume (SV and cardiac output (CO were evaluated between 2.5 and 3.0 hr of hemodialysis. Blood chemicals (sodium, calcium, potassium, and phosphorous and Kt/V before and after each hemodialysis session were analyzed. The number of episodes of hypotension was also recorded. The circulator intervention significantly improved SBP and DBP across all time points (P = 0.002 for SBP; P = 0.002 for DBP. The frequency of hypotension was significantly decreased (P = 0.028. SV and CO were significantly improved with the circulator intervention (P = 0.017 for SV; P = 0.026 for CO and no statistical significances were found on blood chemicals or Kt/V analyses. The results suggested that the circulator intervention helps stabilize blood pressure and appears to be a practical treatment. Future studies are suggested to develop new circulator innovations with sensor feedback systems to enhance safety and maximize treatment efficiency.

  16. Intermittent Hypoxia-Induced Carotid Body Chemosensory Potentiation and Hypertension Are Critically Dependent on Peroxynitrite Formation

    Directory of Open Access Journals (Sweden)

    Esteban A. Moya

    2016-01-01

    Full Text Available Oxidative stress is involved in the development of carotid body (CB chemosensory potentiation and systemic hypertension induced by chronic intermittent hypoxia (CIH, the main feature of obstructive sleep apnea. We tested whether peroxynitrite (ONOO−, a highly reactive nitrogen species, is involved in the enhanced CB oxygen chemosensitivity and the hypertension during CIH. Accordingly, we studied effects of Ebselen, an ONOO− scavenger, on 3-nitrotyrosine immunoreactivity (3-NT-ir in the CB, the CB chemosensory discharge, and arterial blood pressure (BP in rats exposed to CIH. Male Sprague-Dawley rats were exposed to CIH (5% O2, 12 times/h, 8 h/day for 7 days. Ebselen (10 mg/kg/day was administrated using osmotic minipumps and BP measured with radiotelemetry. Compared to the sham animals, CIH-treated rats showed increased 3-NT-ir within the CB, enhanced CB chemosensory responses to hypoxia, increased BP response to acute hypoxia, and hypertension. Rats treated with Ebselen and exposed to CIH displayed a significant reduction in 3-NT-ir levels (60.8 ± 14.9 versus 22.9 ± 4.2 a.u., reduced CB chemosensory response to 5% O2 (266.5 ± 13.4 versus 168.6 ± 16.8 Hz, and decreased mean BP (116.9 ± 13.2 versus 82.1 ± 5.1 mmHg. Our results suggest that CIH-induced CB chemosensory potentiation and hypertension are critically dependent on ONOO− formation.

  17. The immobility produced by intermittent swim stress is not mediated by serotonin.

    Science.gov (United States)

    Christianson, John P; Rabbett, Sarah; Lyckland, Jennifer; Drugan, Robert C

    2008-05-01

    Exposure to uncontrollable stressors such as intermittent swim stress (ISS) produces a behavioral syndrome that resembles behavioral depression including immobility in a Forced Swim Test (FST) and escape learning deficits. The results of previous studies suggest that stress causes a temporary sensitization of the brain serotonin (5-HT) system that is necessary and sufficient for producing behavioral depression. If this hypothesis is true in the ISS paradigm, then enhancing or inhibiting 5-HT transmission during stress should exacerbate or block the development of behavioral depression, respectively. The selective 5-HT uptake inhibitor fluoxetine (FLX) was administered prior to ISS or confinement; 24 h later the FST was used to detect behavioral immobility. ISS, but not FLX, significantly increased immobility in the FST. The purported 5-HT uptake enhancer tianeptine (TPT) was administered in place of FLX. Again ISS increased immobility in the FST, but TPT had no effect. These results suggested that 5-HT is not a critical mediator of ISS induced behavioral depression. However, some authors have raised concern that TPT does not act directly on 5-HT. Therefore, the 5-HT synthesis inhibitor, para-chlorophenylaline (PCPA) was administered to deplete central 5-HT before stress. PCPA did not alter immobility in the FST. Finally, a sub-chronic regimen of FLX given after ISS, but before the FST, was without effect on reversing the ISS-induced immobility. Taken together, these experiments indicate that ISS produces a significant behavioral depression manifested as increased immobility but offer no support of the hypothesis that 5-HT is a critical mediator of these effects.

  18. EVOLUTION OF INTERMITTENCY IN THE SLOW AND FAST SOLAR WIND BEYOND THE ECLIPTIC PLANE

    Energy Technology Data Exchange (ETDEWEB)

    Wawrzaszek, A.; Macek, W. M. [Space Research Centre, Polish Academy of Sciences, Warsaw (Poland); Echim, M. [The Belgian Institute for Space Aeronomy, Brussels (Belgium); Bruno, R., E-mail: anna.wawrzaszek@cbk.waw.pl, E-mail: marius.echim@oma.be, E-mail: macek@cbk.waw.pl, E-mail: roberto.bruno@iaps.inaf.it [Institute for Space Astrophysics and Planetology, Roma (Italy)

    2015-12-01

    We study intermittency as a departure from self-similarity of the solar wind magnetic turbulence and investigate the evolution with the heliocentric distance and latitude. We use data from the Ulysses spacecraft measured during two solar minima (1997–1998 and 2007–2008) and one solar maximum (1999–2001). In particular, by modeling a multifractal spectrum, we revealed the intermittent character of turbulence in the small-scale fluctuations of the magnetic field embedded in the slow and fast solar wind. Generally, at small distances from the Sun, in both the slow and fast solar wind, we observe the high degree of multifractality (intermittency) that decreases somewhat slowly with distance and slowly with latitude. The obtained results seem to suggest that generally intermittency in the solar wind has a solar origin. However, the fast and slow streams, shocks, and other nonlinear interactions can only be considered as the drivers of the intermittent turbulence. It seems that analysis shows that turbulence beyond the ecliptic plane evolves too slowly to maintain the intermittency with the distance and latitude. Moreover, we confirm that the multifractality and intermittency are at a lower level than in the ecliptic, as well as the existence of symmetry with respect to the ecliptic plane, suggesting that there are similar turbulent properties observed in the two hemispheres.

  19. Intermittent aeration to improve wastewater treatment efficiency in pilot-scale constructed wetland.

    Science.gov (United States)

    Uggetti, Enrica; Hughes-Riley, Theodore; Morris, Robert H; Newton, Michael I; Trabi, Christophe L; Hawes, Patrick; Puigagut, Jaume; García, Joan

    2016-07-15

    Forced aeration of horizontal subsurface flow constructed wetlands (HSSF CWs) is nowadays a recognized method to improve treatment efficiency, mainly in terms of ammonium removal. While numerous investigations have been reported testing constant aeration, scarce information can be found about the efficiency of intermittent aeration. This study aims at comparing continuous and intermittent aeration, establishing if there is an optimal regime that will increase treatment efficiency of HSSF CWs whilst minimizing the energy requirement. Full and intermittent aeration were tested in a pilot plant of three HSSF CWs (2.64m(2) each) fed with primary treated wastewater. One unit was fully aerated; one intermittently aerated (i.e. by setting a limit of 0.5mg/L dissolved oxygen within the bed) with the remaining unit not aerated as a control. Results indicated that intermittent aeration was the most successful operating method. Indeed, the coexistence of aerobic and anoxic conditions promoted by the intermittent aeration resulted in the highest COD (66%), ammonium (99%) and total nitrogen (79%) removals. On the other hand, continuous aeration promotes ammonium removal (99%), but resulted in nitrate concentrations in the effluent of up to 27mg/L. This study demonstrates the high potential of the intermittent aeration to increase wastewater treatment efficiency of CWs providing an extreme benefit in terms of the energy consumption. PMID:27062558

  20. Intermittent aeration to improve wastewater treatment efficiency in pilot-scale constructed wetland.

    Science.gov (United States)

    Uggetti, Enrica; Hughes-Riley, Theodore; Morris, Robert H; Newton, Michael I; Trabi, Christophe L; Hawes, Patrick; Puigagut, Jaume; García, Joan

    2016-07-15

    Forced aeration of horizontal subsurface flow constructed wetlands (HSSF CWs) is nowadays a recognized method to improve treatment efficiency, mainly in terms of ammonium removal. While numerous investigations have been reported testing constant aeration, scarce information can be found about the efficiency of intermittent aeration. This study aims at comparing continuous and intermittent aeration, establishing if there is an optimal regime that will increase treatment efficiency of HSSF CWs whilst minimizing the energy requirement. Full and intermittent aeration were tested in a pilot plant of three HSSF CWs (2.64m(2) each) fed with primary treated wastewater. One unit was fully aerated; one intermittently aerated (i.e. by setting a limit of 0.5mg/L dissolved oxygen within the bed) with the remaining unit not aerated as a control. Results indicated that intermittent aeration was the most successful operating method. Indeed, the coexistence of aerobic and anoxic conditions promoted by the intermittent aeration resulted in the highest COD (66%), ammonium (99%) and total nitrogen (79%) removals. On the other hand, continuous aeration promotes ammonium removal (99%), but resulted in nitrate concentrations in the effluent of up to 27mg/L. This study demonstrates the high potential of the intermittent aeration to increase wastewater treatment efficiency of CWs providing an extreme benefit in terms of the energy consumption.

  1. In-out intermittency in partial differential equation and ordinary differential equation models.

    Science.gov (United States)

    Covas, Eurico; Tavakol, Reza; Ashwin, Peter; Tworkowski, Andrew; Brooke, John M.

    2001-06-01

    We find concrete evidence for a recently discovered form of intermittency, referred to as in-out intermittency, in both partial differential equation (PDE) and ordinary differential equation (ODE) models of mean field dynamos. This type of intermittency [introduced in P. Ashwin, E. Covas, and R. Tavakol, Nonlinearity 9, 563 (1999)] occurs in systems with invariant submanifolds and, as opposed to on-off intermittency which can also occur in skew product systems, it requires an absence of skew product structure. By this we mean that the dynamics on the attractor intermittent to the invariant manifold cannot be expressed simply as the dynamics on the invariant subspace forcing the transverse dynamics; the transverse dynamics will alter that tangential to the invariant subspace when one is far enough away from the invariant manifold. Since general systems with invariant submanifolds are not likely to have skew product structure, this type of behavior may be of physical relevance in a variety of dynamical settings. The models employed here to demonstrate in-out intermittency are axisymmetric mean-field dynamo models which are often used to study the observed large-scale magnetic variability in the Sun and solar-type stars. The occurrence of this type of intermittency in such models may be of interest in understanding some aspects of such variabilities. (c) 2001 American Institute of Physics.

  2. Study of intermittent dynamics in the terrestrial foreshock using the Cluster spacecraft records

    Science.gov (United States)

    Kovács, Péter; Vadász, Gergely; Koppán, András; Vörös, Zoltán

    2014-05-01

    The paper concerns with the statistical investigation of the intermittent dynamics in the terrestrial foreshock. We use the 22.5 Hz FGM magnetic data of the four spacecraft of the Cluster mission from periods when the mission orbit traversed the solar wind (January-April in the years of 2001-2010). Intermittency is studied in terms of space and time through a sliding-window probability density function (PDF) analysis of the records. The spatial dependence of the appearance of intermittent fluctuations is monitored according to the distance from the bow shock (BS) and the angle measured between the BS normal and the IMF direction (quasi parallel and perpendicular conditions). Beside the intermittent turbulent fluctuations, the foreshock dynamics is dominated by various wave phenomena, that are, in most cases, more energetic than the turbulent activity. For this reason, a high-pass wavelet filtering is carried out on the time-series for extracting the small-amplitude intermittent fluctuations at high-frequencies. The level of intermittent fluctuations is measured through the deviation of the fourth statistical moments of the time-series increments (i.e. the flatness) from the Gaussian value, 3. Instead of temporal increments, the PDF analysis is also carried out with spatial differences among the records of the four Cluster spacecraft. In this case the Taylor hypothesis has not to be invoked in the interpretation of the obtained results. It is shown that the intermittency level measured by spatial differences decreases logarithmically with the inter-spacecraft distance. The level of intermittent fluctuations in the foreshock is studied in terms of different solar wind conditions. The strongest correlation turns out to be between the intensity of intermittent foreshock dynamics and the solar wind bulk velocity and Alfvén Mach number. The research leading to these results has received funding from the European Community's Seventh Framework Programme ([FP7

  3. Clinical study of intermittent lock of the temporomandibular joint. Relation to frequency of intermittent lock on clinical examination and magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ide, Takashi; Nagai, Itaru; Miyazaki, Akihiro; Yamaguchi, Akira; Kohama, Geniku [Sapporo Medical Univ. (Japan). School of Medicine

    2002-03-01

    To examine the occurrence of intermittent lock, we investigated the correlation between the frequency of intermittent lock of the temporomandibular joint and magnetic resonance imaging (MRI) findings. The subjects consisted of 25 patients (25 joints) with unilateral intermittent lock who were treated from April 1994 through March 2000 at our department. MRI examination of the joint was performed on the affected side. We divided the patients into two groups: a high-frequency group consisting of 15 patients who had symptoms of intermittent lock every day and a low-frequency group consisting of 10 patients who did not have symptoms every day. The results showed no statistical difference between the two groups in clinical findings such as age, sex, clicking side of the joint, duration of intermittent lock, method of unlocking, muscle pain on palpation, degree of maximal mouth opening, distance between the maxillary and mandibular tooth midline, or the degree of overbite and overjet. However, the two groups differed significantly in the degree of anterior disc displacement as assessed by MRI. (author)

  4. Solar system plasma Turbulence: Observations, inteRmittency and Multifractals

    Science.gov (United States)

    Echim, Marius M.

    2016-04-01

    The FP7 project STORM is funded by the European Commission to "add value to existing data bases through a more comprehensive interpretation". STORM targets plasma and magnetic field databases collected in the solar wind (Ulysses and also some planetary missions), planetary magnetospheres (Venus Express, Cluster, a few orbits from Cassini), cometary magnetosheaths (e.g. Haley from Giotto observations). The project applies the same package of analysis methods on geomagnetic field observations from ground and on derived indices (e.g. AE, AL, AU, SYM-H). The analysis strategy adopted in STORM is built on the principle of increasing complexity, from lower (like, e.g., the Power Spectral Density - PSD) to higher order analyses (the Probability Distribution Functions - PDFs, Structure Functions - SFs, Fractals and Multifractals - MFs). Therefore STORM targets not only the spectral behavior of turbulent fluctuations but also their topology and scale behavior inferred from advanced mathematical algorithms and geometrical-like analogs. STORM started in January 2013 and ended in December 2015. We will report on a selection of scientific and technical achievements and will highlight: (1) the radial evolution of solar wind turbulence and intermittency based on Ulysses data with some contributions from Venus Express and Cluster; (2) comparative study of fast and slow wind turbulence and intermittency at solar minimum; (3) comparative study of the planetary response (Venus and Earth magnetosheaths) to turbulent solar wind; (4) the critical behavior of geomagnetic fluctuations and indices; (5) an integrated library for non-linear analysis of time series that includes all the approaches adopted in STORM to investigate solar system plasma turbulence. STORM delivers an unprecedented volume of analysed data for turbulence. The project made indeed a systematic survey, orbit by orbit, of data available from ESA repositories and Principal Investigators and provides results ordered as a

  5. Diffusion, intermittency and scaling in wave breaking turbulence

    Science.gov (United States)

    Redondo, J. M.; Mosso, C.; Marino, R.

    2009-04-01

    Measurements of 3D turbulent velocity have been made near the coast for a variety of weather conditions in the wave breaking zone, and these values have been compared with flume measurements at a 100m long wave tank. There is a strong dependence of the integral lenthscales with the Wave Reynolds number as well as with the position and the wind, quantified through the friction velocity from wind profiles measured at the coastline. Earlier results have been published in Bezerra et al. (1998) and Rodriguez et al(1999). Several effects are important and give several decades of variation of eddy diffusivities measured near the coastline (between 0.0001 and 2 m2s-1)Inman et al.(1971), Zeitler(1976). Measurements of electromagnetic and ADV velocity measurements of the Coastal wave generated turbulence are compared in order to invest the scaling and intermittency of the turbulence produced by wave breaking. The velocity measurements were performed with an array of electromagnetic sensors that could be placed along the coastline in a stainless steel sledge. Rodriguez et al.(1994,1999) showed a parabolic shape of cross-shore diffusivity values but present analysis also shows the crosshore dependence of the intermittency as well as changes in the spectral slopes. Bezerra M.O., Diez M., Medeiros C., Rodriguez A., Bahia E. Sanchez-Arcilla A. y Redondo J.M. (1998) Study on the influence of waves on coastal diffusion using image analysis Applied Scientific Research. 59, 191-204. Rodriguez A., Sanchez-Arcilla A., Redondo J.M and C. Mosso (1999) Macroturbulence measurements with electromagnetic and ultrasonic sensors: a comparison under high-turbulent flows. Experiments in Fluids, 27, 31-42. Inman, D. L.; Tait, R.J.; Nordstrom, C.E. (1971). Mixing in the surf zone. Journal of Geophysical Research, vol 76, n° 15, 3493 - 3514. Zeidler, R. B. (1976) Coastal dispersion of pollutants, Journal of the Waterways Harbors and Coastal Engineering Division, 235 - 254 p. Rodriguez, A.; Bahia

  6. Repetetive hindlimb movement using intermittent adaptive neuromuscular electrical stimulation in an incomplete spinal cord injury rodent model.

    Science.gov (United States)

    Fairchild, Mallika D; Kim, Seung-Jae; Iarkov, Alex; Abbas, James J; Jung, Ranu

    2010-06-01

    The long-term objective of this work is to understand the mechanisms by which electrical stimulation based movement therapies may harness neural plasticity to accelerate and enhance sensorimotor recovery after incomplete spinal cord injury (iSCI). An adaptive neuromuscular electrical stimulation (aNMES) paradigm was implemented in adult Long Evans rats with thoracic contusion injury (T8 vertebral level, 155+/-2 Kdyne). In lengthy sessions with lightly anesthetized animals, hip flexor and extensor muscles were stimulated using an aNMES control system in order to generate desired hip movements. The aNMES control system, which used a pattern generator/pattern shaper structure, adjusted pulse amplitude to modulate muscle force in order to control hip movement. An intermittent stimulation paradigm was used (5-cycles/set; 20-second rest between sets; 100 sets). In each cycle, hip rotation caused the foot plantar surface to contact a stationary brush for appropriately timed cutaneous input. Sessions were repeated over several days while the animals recovered from injury. Results indicated that aNMES automatically and reliably tracked the desired hip trajectory with low error and maintained range of motion with only gradual increase in stimulation during the long sessions. Intermittent aNMES thus accounted for the numerous factors that can influence the response to NMES: electrode stability, excitability of spinal neural circuitry, non-linear muscle recruitment, fatigue, spinal reflexes due to cutaneous input, and the endogenous recovery of the animals. This novel aNMES application in the iSCI rodent model can thus be used in chronic stimulation studies to investigate the mechanisms of neuroplasticity targeted by NMES-based repetitive movement therapy. PMID:20206164

  7. Chronic kidney disease

    Science.gov (United States)

    Kidney failure - chronic; Renal failure - chronic; Chronic renal insufficiency; Chronic kidney failure; Chronic renal failure ... 2012_CKD_GL.pdf . McCullough PA. Interface between renal disease ... patients with kidney failure. N Engl J Med . 2010;362(14):1312- ...

  8. Synchronization analysis of coloured delayed networks under decentralized pinning intermittent control

    Indian Academy of Sciences (India)

    JIANG SHENGQIN; LU XIAOBO

    2016-06-01

    This paper investigates synchronization of coloured delayed networks under decentralized pinning intermittent control. To begin with, the time delays are taken into account in the coloured networks. In addition, we propose a decentralized pinning intermittent control for coloured delayed networks, which is different from that most of pinning intermittent controls are only appliedto the nodes from 1 to l or centralized nodes. Moreover, sufficient conditions are derived to guarantee the synchronization of coloured delayed networks based on Lyapunov stability theorem. Finally, numerical simulations are provided to verify the validity of the obtained results.

  9. Intermittent magnetic field excitation by a turbulent flow of liquid sodium

    CERN Document Server

    Nornber, M D; Kendrick, R D; Jacobson, C M; Forest, C B

    2006-01-01

    The magnetic field measured in the Madison Dynamo Experiment shows intermittent periods of growth when an axial magnetic field is applied. The geometry of the intermittent field is consistent with the fastest growing magnetic eigenmode predicted by kinematic dynamo theory using a laminar model of the mean flow. Though the eigenmodes of the mean flow are decaying, it is postulated that turbulent fluctuations of the velocity field change the flow geometry such that the eigenmode growth rate is temporarily positive. Therefore, it is expected that a characteristic of the onset of a turbulent dynamo is magnetic intermittency.

  10. Probabilistic signatures of spatiotemporal intermittency in the coupled sine circle map lattice

    Indian Academy of Sciences (India)

    Zahera Jabeen; Neelima Gupta

    2008-06-01

    The phase diagram of the coupled sine circle map system exhibits a variety of interesting phenomena including spreading regions with spatiotemporal intermittency, non-spreading regions with spatial intermittency, and coherent structures termed solitons. A spreading to non-spreading transition is seen in the system. A cellular automaton version of the coupled system maps the spreading to non-spreading transition to a transition from a probabilistic to a deterministic cellular automaton. The solitonic sector of the system shows spatiotemporal intermittency with soliton creation, propagation and absorption. A probabilistic cellular automaton mapping is set up for this sector which can identify each one of these phenomena.

  11. Measurement and mathematical model of a driver's intermittent compensatory steering control

    Science.gov (United States)

    Johns, Tim A.; Cole, David J.

    2015-12-01

    The compensatory (feedback) component of a human driver's steering control is examined. In particular, the effect of the cognitive process is studied. Model predictive control theory is used to implement models of intermittency in cognitive processing. Experiments using a fixed-base driving simulator with periodic occlusion of the visual display are used to reveal the nature of the driver's steering behaviour. An intermittent serial-ballistic control strategy is found to match the measured behaviour better than intermittent zero-order hold or continuous control. The findings may enable some insight to driver-vehicle interaction and vehicle handling qualities.

  12. Sodium bicarbonate intake improves high-intensity intermittent exercise performance in trained young men

    DEFF Research Database (Denmark)

    Krustrup, Peter; Ermidis, Georgios; Mohr, Magni

    2015-01-01

    Background Sodium bicarbonate intake has been shown to improve exercise tolerance, but the effects on high-intensity intermittent exercise are less clear. Thus, the aim of the present study was to determine the effect of sodium bicarbonate intake on Yo-Yo intermittent recovery level 2 test perfor......-intensity intermittent exercise performance is improved by prior intake of sodium bicarbonate in trained young men, with concomitant elevations in blood alkalosis and peak blood lactate levels, as well as lowered rating of perceived exertion....

  13. Changes in the Adult GluN2B Associated Proteome following Adolescent Intermittent Ethanol Exposure.

    Directory of Open Access Journals (Sweden)

    H Scott Swartzwelder

    Full Text Available Adolescent alcohol use is the strongest predictor for alcohol use disorders. In rodents, adolescents have distinct responses to acute ethanol, and prolonged alcohol exposure during adolescence can maintain these phenotypes into adulthood. One brain region that is particularly sensitive to the effects of both acute and chronic ethanol exposure is the hippocampus. Adolescent intermittent ethanol exposure (AIE produces long lasting changes in hippocampal synaptic plasticity and dendritic morphology, as well as in the susceptibility to acute ethanol-induced spatial memory impairment. Given the pattern of changes in hippocampal structure and function, one potential target for these effects is the ethanol sensitive GluN2B subunit of the NMDA receptor, which is known to be involved in synaptic plasticity and dendritic morphology. Thus we sought to determine if there were persistent changes in hippocampal GluN2B signaling cascades following AIE. We employed a previously validated GluN2B-targeted proteomic strategy that was used to identify novel signaling mechanisms altered by chronic ethanol exposure in the adult hippocampus. We collected adult hippocampal tissue (P70 from rats that had been given 2 weeks of AIE from P30-45. Tissue extracts were fractionated into synaptic and non-synaptic pools, immuno-precipitated for GluN2B, and then analyzed using proteomic methods. We detected a large number of proteins associated with GluN2B. AIE produced significant changes in the association of many proteins with GluN2B in both synaptic and non-synaptic fractions. Intriguingly the number of proteins changed in the non-synaptic fraction was double that found in the synaptic fraction. Some of these proteins include those involved in glutamate signaling cytoskeleton rearrangement, calcium signaling, and plasticity. Disruptions in these pathways may contribute to the persistent cellular and behavioral changes found in the adult hippocampus following AIE. Further

  14. Changes in the Adult GluN2B Associated Proteome following Adolescent Intermittent Ethanol Exposure

    Science.gov (United States)

    Swartzwelder, H. Scott; Risher, Mary-Louise; Miller, Kelsey M.; Colbran, Roger J.; Winder, Danny G.; Wills, Tiffany A.

    2016-01-01

    Adolescent alcohol use is the strongest predictor for alcohol use disorders. In rodents, adolescents have distinct responses to acute ethanol, and prolonged alcohol exposure during adolescence can maintain these phenotypes into adulthood. One brain region that is particularly sensitive to the effects of both acute and chronic ethanol exposure is the hippocampus. Adolescent intermittent ethanol exposure (AIE) produces long lasting changes in hippocampal synaptic plasticity and dendritic morphology, as well as in the susceptibility to acute ethanol-induced spatial memory impairment. Given the pattern of changes in hippocampal structure and function, one potential target for these effects is the ethanol sensitive GluN2B subunit of the NMDA receptor, which is known to be involved in synaptic plasticity and dendritic morphology. Thus we sought to determine if there were persistent changes in hippocampal GluN2B signaling cascades following AIE. We employed a previously validated GluN2B-targeted proteomic strategy that was used to identify novel signaling mechanisms altered by chronic ethanol exposure in the adult hippocampus. We collected adult hippocampal tissue (P70) from rats that had been given 2 weeks of AIE from P30-45. Tissue extracts were fractionated into synaptic and non-synaptic pools, immuno-precipitated for GluN2B, and then analyzed using proteomic methods. We detected a large number of proteins associated with GluN2B. AIE produced significant changes in the association of many proteins with GluN2B in both synaptic and non-synaptic fractions. Intriguingly the number of proteins changed in the non-synaptic fraction was double that found in the synaptic fraction. Some of these proteins include those involved in glutamate signaling cytoskeleton rearrangement, calcium signaling, and plasticity. Disruptions in these pathways may contribute to the persistent cellular and behavioral changes found in the adult hippocampus following AIE. Further, the robust change in

  15. A Prospective, Randomized, Crossover, Multicenter Study Comparing Quality of Life Using Compact versus Standard Catheters for Intermittent Self-Catheterization

    DEFF Research Database (Denmark)

    Chartier-Kastler, Emmanuel; Amarenco, Gérard; Lindbo, Lena;

    2013-01-01

    Intermittent catheterization is the recommended standard treatment for neurogenic bladder dysfunction. However, standard intermittent catheters can be unwieldy, difficult to use and carry discreetly. This can influence patient ability to perform catheterization efficiently, discreetly and private......, therefore, affecting patient quality of life. We evaluated whether the discreet design of the compact catheter would improve quality of life in intermittent catheterization users compared with standard catheters.......Intermittent catheterization is the recommended standard treatment for neurogenic bladder dysfunction. However, standard intermittent catheters can be unwieldy, difficult to use and carry discreetly. This can influence patient ability to perform catheterization efficiently, discreetly and privately...

  16. Efficient pricing and investment in electricity markets with intermittent resources

    International Nuclear Information System (INIS)

    Facing growing technological and environmental challenges, the electricity industry needs effective pricing mechanism to promote efficient risk management and investment decisions. In a restructured electricity market with competitive wholesale prices and traditionally regulated retail rates, however, there are technical and institutional barriers that prevent dynamic pricing with price responsive demand. In regions with limited energy storage capacity, intermittent renewable resources present special challenges. This could adversely affect the effectiveness of public policies causing inefficient investments in energy technologies. In this paper, we present an updated economic model of pricing and investment in restructured electricity market and use the model in a simulation study for an initial assessment of renewable energy strategy and alternative pricing mechanisms. A key objective of the study is to shed light on the policy issues so that effective decisions can be made to improve efficiency. - Highlights: → Renewable resources present special challenges in regions with limited energy storage capacity. → This paper presents an updated economic model of pricing and investment in restructured electricity market. → A simulation study assesses renewable energy strategy and alternative pricing mechanisms. → The study results inform policy decisions to improve efficient investments in energy technologies.

  17. Intermittent Oral Versus Intravenous Alfacalcidol in Dialysis Patients

    Directory of Open Access Journals (Sweden)

    Mitwalli Ahmed

    2000-01-01

    Full Text Available Patients with end-stage renal failure (ESRF on maintenance dialysis, commonly develop secondary hyperparathyroidism and renal osteodystrophy (ROD. Alfacalcidol, taken orally or administered intravenously, is known to reverse these complications. In this study, 19 ESRF patients, who were on dialysis (13 on hemodialysis and six on peritoneal dialysis for longer than six months and having serum parathormone levels at least four times normal and serum calcium less than 2.1 mmol/L, were randomly allocated to treatment with oral or intravenous (i.v. alfacalcidol for a period of 12 months. There were six patients on hemodialysis (HD and three on peritoneal dialysis (PD in the oral treatment group while in the i.v. group there were seven patients on HD and three on PD. Clinical and serial biochemical assessments showed no statistically significant difference between the orally- and i.v.-treated patients in terms of suppressing secondary hyperparathyroidism and osteodystrophy. However, patients with features of mild ROD on bone histology, had more satisfactory changes in biochemistry when compared to others. Our results further support the use of intermittent oral alfacalcidol in ESRF patients because of its cost effectiveness, ease of administration and convenience, especially for peritoneal dialysis patients.

  18. Optimal Intermittent Dose Schedules for Chemotherapy Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Nadia ALAM

    2013-08-01

    Full Text Available In this paper, a design method for optimal cancer chemotherapy schedules via genetic algorithm (GA is presented. The design targets the key objective of chemotherapy to minimize the size of cancer tumor after a predefined time with keeping toxic side effects in limit. This is a difficult target to achieve using conventional clinical methods due to poor therapeutic indices of existing anti-cancer drugs. Moreover, there are clinical limitations in treatment administration to maintain continuous treatment. Besides, carefully decided rest periods are recommended to for patient’s comfort. Three intermittent drug scheduling schemes are presented in this paper where GA is used to optimize the dose quantities and timings by satisfying several treatment constraints. All three schemes are found to be effective in total elimination of cancer tumor after an agreed treatment length. The number of cancer cells is found zero at the end of the treatment for all three cases with tolerable toxicity. Finally, two of the schemes, “Fixed interval variable dose (FIVD and “Periodic dose” that are periodic in characteristic have been emphasized due to their additional simplicity in administration along with friendliness to patients. responses to the designed treatment schedules. Therefore the proposed design method is capable of planning effective, simple, patient friendly and acceptable chemotherapy schedules.

  19. Forage production of elephant grass under intermittent stocking

    Directory of Open Access Journals (Sweden)

    Carla Silva Chaves

    2013-02-01

    Full Text Available The objective of this work was to evaluate the dry matter production of elephant grass (Pennisetum purpureum genotypes, managed under intermittent stocking. A completely randomized design was used, with two genotypes and three replicates. The treatments consisted of factorial combinations (2x2x2 of genotypes ('BRS Kurumi' and the clone CNPGL 00‑1‑3, two light interception levels (LI at the onset of grazing (90 and 95%, and two post‑grazing canopy heights (30 and 50 cm. A total of 24 Holstein x Zebu crossbred heifers were used. The stocking density varied in order to finish the grazing periods in two days. The interval between the defoliation, based on 95% LI, resulted in a higher leaf mass per grazing cycle. The post‑grazing height of 30 cm did not affect the number of grazing cycles but provided a greater herbage accumulation rate. The cultivar BRS Kurumi has higher pasture growth, lower rest period, and greater number of grazing cycles, which results in increased forage production in the growing season.

  20. A Mathematical Model of Intermittent Androgen Suppression for Prostate Cancer

    Science.gov (United States)

    Ideta, Aiko Miyamura; Tanaka, Gouhei; Takeuchi, Takumi; Aihara, Kazuyuki

    2008-12-01

    For several decades, androgen suppression has been the principal modality for treatment of advanced prostate cancer. Although the androgen deprivation is initially effective, most patients experience a relapse within several years due to the proliferation of so-called androgen-independent tumor cells. Bruchovsky et al. suggested in animal models that intermittent androgen suppression (IAS) can prolong the time to relapse when compared with continuous androgen suppression (CAS). Therefore, IAS has been expected to enhance clinical efficacy in conjunction with reduction in adverse effects and improvement in quality of life of patients during off-treatment periods. This paper presents a mathematical model that describes the growth of a prostate tumor under IAS therapy based on monitoring of the serum prostate-specific antigen (PSA). By treating the cancer tumor as a mixed assembly of androgen-dependent and androgen-independent cells, we investigate the difference between CAS and IAS with respect to factors affecting an androgen-independent relapse. Numerical and bifurcation analyses show how the tumor growth and the relapse time are influenced by the net growth rate of the androgen-independent cells, a protocol of the IAS therapy, and the mutation rate from androgen-dependent cells to androgen-independent ones.

  1. Intermittent control models of human standing: similarities and differences.

    Science.gov (United States)

    Gawthrop, Peter; Loram, Ian; Gollee, Henrik; Lakie, Martin

    2014-04-01

    Two architectures of intermittent control are compared and contrasted in the context of the single inverted pendulum model often used for describing standing in humans. The architectures are similar insofar as they use periods of open-loop control punctuated by switching events when crossing a switching surface to keep the system state trajectories close to trajectories leading to equilibrium. The architectures differ in two significant ways. Firstly, in one case, the open-loop control trajectory is generated by a system-matched hold, and in the other case, the open-loop control signal is zero. Secondly, prediction is used in one case but not the other. The former difference is examined in this paper. The zero control alternative leads to periodic oscillations associated with limit cycles; whereas the system-matched control alternative gives trajectories (including homoclinic orbits) which contain the equilibrium point and do not have oscillatory behaviour. Despite this difference in behaviour, it is further shown that behaviour can appear similar when either the system is perturbed by additive noise or the system-matched trajectory generation is perturbed. The purpose of the research is to come to a common approach for understanding the theoretical properties of the two alternatives with the twin aims of choosing which provides the best explanation of current experimental data (which may not, by itself, distinguish between the two alternatives) and suggesting future experiments to distinguish between the two alternatives. PMID:24500616

  2. Intravesical oxybutinin chloride in children with intermittent catheterization: sonographic findings.

    Science.gov (United States)

    Zerin, J M; DiPietro, M A; Ritchey, M L; Bloom, D A

    1994-01-01

    The sonographic findings in the bladder are presented in four children with myelomeningocele and neurogenic dysfunction of the bladder, who were treated with intermittent self-catheterization and intravesical oxybutinin chloride. All were referred for routine sonography of the urinary tract. Each had infused a crushed tablet of oxybutinin chloride intravesically 30-120 min before the examination. In two children, brightly echogenic, non-shadowing particles were suspended in the bladder urine. In one of these, the particles swirled giving the impression of a "snowstorm"; in the other, most of the particles gradually settled forming an irregular clump on the bladder base. In the remaining two children, the urine appeared diffusely hazy with innumerable tiny particles giving the impression of a fine mist filling the bladder. The sonographic appearance of the urine in the bladder after intravesical instillation of crushed tablets can be dramatic and can simulate pus, blood, fungus, or other debris in the bladder lumen. In the absence of clinical symptoms or hematuria, a history of recent infusion of medication into the bladder should be sought.

  3. Intermittent Brugada Syndrome Presenting with Syncope in an Adult Female

    Directory of Open Access Journals (Sweden)

    Patricia Chavez

    2014-01-01

    Full Text Available Background. Brugada syndrome accounts for 4–12% of all sudden deaths worldwide and at least 20% of sudden deaths in patients with structurally normal hearts. Case Report. A 48-year-old female presented to the emergency department after two witnessed syncopal episodes. While awaiting discharge had a third collapse followed by cardiac arrest with shockable rhythm. Initial electrocardiogram showed wide QRS complex with left axis deviation, ST-segment elevation of 2 mm followed by a negative T wave with no isoelectric separation, suggestive of spontaneous intermittent Brugada type 1 pattern. Cardiac magnetic resonance imaging demonstrated neither structural heart disease nor abnormal myocardium. After placement of an implantable cardioverter defibrillator the patient was discharged. Why should an emergency physician be aware of this? Brugada syndrome is an infrequently encountered clinical entity which may have a fatal outcome. This syndrome primarily presents with syncope. It should be considered as a component of differential diagnosis in patients with family history of syncope and sudden cardiac death.

  4. Movement mechanisms of gross solids in intermittent flow.

    Science.gov (United States)

    Littlewood, K; Butler, D

    2003-01-01

    Gross solids, such as used tampons, sanitary towels and faecal stools, are introduced into the sewer network via the WC. Although small diameter pipes (diameter) make up a large proportion of most sewer networks, the transport behaviour of gross solids in these smaller pipes is not fully established. In particular, there are concerns about the effect of water conservation measures on the transport of gross solids in the intermittent flow regime prevalent in small pipes. This paper introduces a study carried out on the movement of solids in this flow regime. An extensive series of experiments has been carried out to investigate the movement mechanisms and behaviour in detail. It was found that there are three different mechanisms of movement, and photographic evidence is provided in the paper. The concept and implications of the "limiting solid transport distance" is also introduced. It is argued that solid movement is dependent on factors other than just WC flush volume and that increased blockage potential is not inevitable. PMID:12666800

  5. Commercial and Industrial Base Intermittent Resource Management Pilot

    Energy Technology Data Exchange (ETDEWEB)

    Kiliccote, Sila; Sporborg, Pamela; Sheik, Imran; Huffaker, Erich; Piette, Mary Ann

    2010-11-30

    This scoping study summarizes the challenges with integrating wind and solar generation into the California's electricity grid. These challenges include: Smoothing intra-hour variability; - Absorbing excess renewable energy during over-generation periods; - Addressing morning and evening ramping periods. In addition, there are technical challenges to integrating retail demand response (DR) triggered by the wholesale conditions into the CAISO markets. The study describes the DR programs available to the consumers through the utilities in California and CAISO's ancillary services market because an integration of the wholesale and retail DR requires an understanding of these different offerings and the costs associated with acquiring them. Demand-side active and passive storage systems are proposed as technologies that may be used to mitigate the effects of intermittence due to renewable generation. Commercial building technologies as well as industrial facilities with storage capability are identified as targets for the field tests. Two systems used for ancillary services communications are identified as providing the triggers for DR enablement. Through the field tests, issues related to communication, automation and flexibility of demand-side resources will be explored and the performance of technologies that participate in the field tests will be evaluated. The major outcome of this research is identifying and defining flexibility of DR resources and optimized use of these resources to respond to grid conditions.

  6. Role of orthoptic treatment in the management of intermittent exotropia

    Directory of Open Access Journals (Sweden)

    Singh Vinita

    1992-01-01

    Full Text Available 30 patients of intermittent ACDS were studied prospectively for a period of 8 weeks to 1 year to evaluate the role of orthoptics in the management of these cases. In patients with convergence insufficiency and a maximum deviation of 25 PD or less the orthoptic treatment was found to be effective in offering symptomatic relief and improving binocular functional status. A reduction in the maximum angle of deviation by 4 PD to 8 PD was observed in 4 patients. Even though the basic angle of deviation remained unchanged in most of the patients, significant functional and symptomatic improvement was obtained in 64% to 85.7% of these cases. The long term stability of these results remains to be studied. In patients with a deviation of more than 25 PD there was no significant improvement in symptoms or reduction in maximum angle of deviation. In 6(37.5% of these patients some improvement in the fusional range could be demonstrated on the synoptophore without any symptomatic relief.

  7. A stochastic space-time model for intermittent precipitation occurrences

    KAUST Repository

    Sun, Ying

    2016-01-28

    Modeling a precipitation field is challenging due to its intermittent and highly scale-dependent nature. Motivated by the features of high-frequency precipitation data from a network of rain gauges, we propose a threshold space-time t random field (tRF) model for 15-minute precipitation occurrences. This model is constructed through a space-time Gaussian random field (GRF) with random scaling varying along time or space and time. It can be viewed as a generalization of the purely spatial tRF, and has a hierarchical representation that allows for Bayesian interpretation. Developing appropriate tools for evaluating precipitation models is a crucial part of the model-building process, and we focus on evaluating whether models can produce the observed conditional dry and rain probabilities given that some set of neighboring sites all have rain or all have no rain. These conditional probabilities show that the proposed space-time model has noticeable improvements in some characteristics of joint rainfall occurrences for the data we have considered.

  8. Tensor-Based Link Prediction in Intermittently Connected Wireless Networks

    CERN Document Server

    Zayani, Mohamed-Haykel; Slama, Ines; Zeghlache, Djamal

    2011-01-01

    Through several studies, it has been highlighted that mobility patterns in mobile networks are driven by human behaviors. This effect has been particularly observed in intermittently connected networks like DTN (Delay Tolerant Networks). Given that common social intentions generate similar human behavior, it is relevant to exploit this knowledge in the network protocols design, e.g. to identify the closeness degree between two nodes. In this paper, we propose a temporal link prediction technique for DTN which quantifies the behavior similarity between each pair of nodes and makes use of it to predict future links. Our prediction method keeps track of the spatio-temporal aspects of nodes behaviors organized as a third-order tensor that aims to records the evolution of the network topology. After collapsing the tensor information, we compute the degree of similarity for each pair of nodes using the Katz measure. This metric gives us an indication on the link occurrence between two nodes relying on their closene...

  9. Aerodynamic surface stress intermittency and conditionally averaged turbulence statistics

    Science.gov (United States)

    Anderson, William; Lanigan, David

    2015-11-01

    Aeolian erosion is induced by aerodynamic stress imposed by atmospheric winds. Erosion models prescribe that sediment flux, Q, scales with aerodynamic stress raised to exponent, n, where n > 1 . Since stress (in fully rough, inertia-dominated flows) scales with incoming velocity squared, u2, it follows that q ~u2n (where u is some relevant component of the flow). Thus, even small (turbulent) deviations of u from its time-mean may be important for aeolian activity. This rationale is augmented given that surface layer turbulence exhibits maximum Reynolds stresses in the fluid immediately above the landscape. To illustrate the importance of stress intermittency, we have used conditional averaging predicated on stress during large-eddy simulation of atmospheric boundary layer flow over an arid, bare landscape. Conditional averaging provides an ensemble-mean visualization of flow structures responsible for erosion `events'. Preliminary evidence indicates that surface stress peaks are associated with the passage of inclined, high-momentum regions flanked by adjacent low-momentum regions. We characterize geometric attributes of such structures and explore streamwise and vertical vorticity distribution within the conditionally averaged flow field. This work was supported by the National Sci. Foundation, Phys. and Dynamic Meteorology Program (PM: Drs. N. Anderson, C. Lu, and E. Bensman) under Grant # 1500224. Computational resources were provided by the Texas Adv. Comp. Center at the Univ. of Texas.

  10. Assimilating uncertain, dynamic and intermittent streamflow observations in hydrological models

    Science.gov (United States)

    Mazzoleni, Maurizio; Alfonso, Leonardo; Chacon-Hurtado, Juan; Solomatine, Dimitri

    2015-09-01

    Catastrophic floods cause significant socio-economical losses. Non-structural measures, such as real-time flood forecasting, can potentially reduce flood risk. To this end, data assimilation methods have been used to improve flood forecasts by integrating static ground observations, and in some cases also remote sensing observations, within water models. Current hydrologic and hydraulic research works consider assimilation of observations coming from traditional, static sensors. At the same time, low-cost, mobile sensors and mobile communication devices are becoming also increasingly available. The main goal and innovation of this study is to demonstrate the usefulness of assimilating uncertain streamflow observations that are dynamic in space and intermittent in time in the context of two different semi-distributed hydrological model structures. The developed method is applied to the Brue basin, where the dynamic observations are imitated by the synthetic observations of discharge. The results of this study show how model structures and sensors locations affect in different ways the assimilation of streamflow observations. In addition, it proves how assimilation of such uncertain observations from dynamic sensors can provide model improvements similar to those of streamflow observations coming from a non-optimal network of static physical sensors. This can be a potential application of recent efforts to build citizen observatories of water, which can make the citizens an active part in information capturing, evaluation and communication, helping simultaneously to improvement of model-based flood forecasting.

  11. Intravesical oxybutinin chloride in children with intermittent catheterization: sonographic findings.

    Science.gov (United States)

    Zerin, J M; DiPietro, M A; Ritchey, M L; Bloom, D A

    1994-01-01

    The sonographic findings in the bladder are presented in four children with myelomeningocele and neurogenic dysfunction of the bladder, who were treated with intermittent self-catheterization and intravesical oxybutinin chloride. All were referred for routine sonography of the urinary tract. Each had infused a crushed tablet of oxybutinin chloride intravesically 30-120 min before the examination. In two children, brightly echogenic, non-shadowing particles were suspended in the bladder urine. In one of these, the particles swirled giving the impression of a "snowstorm"; in the other, most of the particles gradually settled forming an irregular clump on the bladder base. In the remaining two children, the urine appeared diffusely hazy with innumerable tiny particles giving the impression of a fine mist filling the bladder. The sonographic appearance of the urine in the bladder after intravesical instillation of crushed tablets can be dramatic and can simulate pus, blood, fungus, or other debris in the bladder lumen. In the absence of clinical symptoms or hematuria, a history of recent infusion of medication into the bladder should be sought. PMID:7824373

  12. Nonlinear random optical waves: Integrable turbulence, rogue waves and intermittency

    Science.gov (United States)

    Randoux, Stéphane; Walczak, Pierre; Onorato, Miguel; Suret, Pierre

    2016-10-01

    We examine the general question of statistical changes experienced by ensembles of nonlinear random waves propagating in systems ruled by integrable equations. In our study that enters within the framework of integrable turbulence, we specifically focus on optical fiber systems accurately described by the integrable one-dimensional nonlinear Schrödinger equation. We consider random complex fields having a Gaussian statistics and an infinite extension at initial stage. We use numerical simulations with periodic boundary conditions and optical fiber experiments to investigate spectral and statistical changes experienced by nonlinear waves in focusing and in defocusing propagation regimes. As a result of nonlinear propagation, the power spectrum of the random wave broadens and takes exponential wings both in focusing and in defocusing regimes. Heavy-tailed deviations from Gaussian statistics are observed in focusing regime while low-tailed deviations from Gaussian statistics are observed in defocusing regime. After some transient evolution, the wave system is found to exhibit a statistically stationary state in which neither the probability density function of the wave field nor the spectrum changes with the evolution variable. Separating fluctuations of small scale from fluctuations of large scale both in focusing and defocusing regimes, we reveal the phenomenon of intermittency; i.e., small scales are characterized by large heavy-tailed deviations from Gaussian statistics, while the large ones are almost Gaussian.

  13. Green Tea, Intermittent Sprinting Exercise, and Fat Oxidation

    Directory of Open Access Journals (Sweden)

    Daniel Gahreman

    2015-07-01

    Full Text Available Fat oxidation has been shown to increase after short term green tea extract (GTE ingestion and after one bout of intermittent sprinting exercise (ISE. Whether combining the two will result in greater fat oxidation after ISE is undetermined. The aim of the current study was to investigate the combined effect of short term GTE and a single session of ISE upon post-exercise fat oxidation. Fourteen women consumed three GTE or placebo capsules the day before and one capsule 90 min before a 20-min ISE cycling protocol followed by 1 h of resting recovery. Fat oxidation was calculated using indirect calorimetry. There was a significant increase in fat oxidation post-exercise compared to at rest in the placebo condition (p < 0.01. After GTE ingestion, however, at rest and post-exercise, fat oxidation was significantly greater (p < 0.05 than that after placebo. Plasma glycerol levels at rest and 15 min during post-exercise were significantly higher (p < 0.05 after GTE consumption compared to placebo. Compared to placebo, plasma catecholamines increased significantly after GTE consumption and 20 min after ISE (p < 0.05. Acute GTE ingestion significantly increased fat oxidation under resting and post-exercise conditions when compared to placebo.

  14. SP Monitoring of Intermittent Flow Through Covered-Karst Sinkholes

    Science.gov (United States)

    Bumpus, P. B.; Kruse, S. E.

    2010-12-01

    A year of continuous SP (self-potential) monitoring was combined with high-resolution 3-D GPR surveys and intermittent water table monitoring over two small covered-karst conduits in Tampa, Florida. SP readings were logged over ~30 electrodes at 2-minute intervals. Positive and negative SP anomalies episodically manifested over conduits, suggesting that conduit flow is dynamic, not static. Three distinct SP flow regimes in the conduits are postulated: fast flow through the conduit to the underlying aquifer, slow flow to the confining layer through the collapse conduit walls, and a conduit plugged high enough to behave like the rest of the confining layer. SP responses after rain events appear to measure the effects of two wetting front curves, one striking the monitoring electrode, one the reference. By comparing curve shapes for all possible pairs of electrodes, it may be possible to establish surficial infiltration and flow patterns. SP is also strongly affected by soil conductivity, rainfall history, and cultural noise. Further concurrent study of moisture content and SP with a suite of reference electrodes placed in various topographic, vegetative, geologic, and climatic settings will help distinguish groundwater flow from other sources affecting SP measurements.

  15. Atypical Chronic Myelogenous Leukemia

    Science.gov (United States)

    ... myeloproliferative neoplasms, leukemia , and other conditions . Chronic Myelomonocytic Leukemia Key Points Chronic myelomonocytic leukemia is a disease ... chance of recovery) and treatment options. Chronic myelomonocytic leukemia is a disease in which too many myelocytes ...

  16. Intermittent observer-based consensus control for multi-agent systems with switching topologies

    Science.gov (United States)

    Xu, Xiaole; Gao, Lixin

    2016-06-01

    In this paper, we focus on the consensus problem for leaderless and leader-followers multi-agent systems with periodically intermittent control. The dynamics of each agent in the system is a linear system, and the interconnection topology among the agents is assumed to be switching. We assume that each agent can only share the outputs with its neighbours. Therefore, a class of distributed intermittent observer-based consensus protocols are proposed for each agent. First, in order to solve this problem, a parameter-dependent common Lyapunov function is constructed. Using this function, we prove that all agents can access a prescribed value, under the designed intermittent controller and observer, if there are suitable conditions on communication. Second, based on the investigation of the leader-following consensus problem, we design a new distributed intermittent observer-based protocol for each following agent. Finally, we provide an illustrative example to verify the effectiveness of the proposed approach.

  17. Maintenance immunosuppression with intermittent intravenous IL-2 receptor antibody therapy in renal transplant recipients.

    LENUS (Irish Health Repository)

    Gabardi, Steven

    2011-09-01

    To report what we believe to be the first 2 cases of long-term (>24 months) intermittent intravenous interleukin-2 receptor antibody (IL-2RA) therapy for maintenance immunosuppression following renal transplantation.

  18. Critical behavior of the Lyapunov exponent in type-III intermittency

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Llamoza, O. [Departamento de Fisica, FACYT, Universidad de Carabobo, Valencia (Venezuela); Centro de Fisica Fundamental, Grupo de Caos y Sistemas Complejos, Universidad de Los Andes, Merida 5251, Merida (Venezuela)], E-mail: llamoza@ula.ve; Cosenza, M.G. [Centro de Fisica Fundamental, Grupo de Caos y Sistemas Complejos, Universidad de Los Andes, Merida 5251, Merida (Venezuela); Ponce, G.A. [Departamento de Fisica, Universidad Nacional Autonoma de Honduras (Honduras); Departamento de Ciencias Naturales, Universidad Pedagogica Nacional Francisco Morazan, Tegucigalpa (Honduras)

    2008-04-15

    The critical behavior of the Lyapunov exponent near the transition to robust chaos via type-III intermittency is determined for a family of one-dimensional singular maps. Critical boundaries separating the region of robust chaos from the region where stable fixed points exist are calculated on the parameter space of the system. A critical exponent {beta} expressing the scaling of the Lyapunov exponent is calculated along the critical curve corresponding to the type-III intermittent transition to chaos. It is found that {beta} varies on the interval 0 {<=} {beta} < 1/2 as a function of the order of the singularity of the map. This contrasts with earlier predictions for the scaling behavior of the Lyapunov exponent in type-III intermittency. The variation of the critical exponent {beta} implies a continuous change in the nature of the transition to chaos via type-III intermittency, from a second-order, continuous transition to a first-order, discontinuous transition.

  19. Changes in pulmonary blood flow do not affect gas exchange during intermittent ventilation in resting turtles

    DEFF Research Database (Denmark)

    Wang, Tobias; Hicks, James W.

    2008-01-01

    The breathing pattern of many different air-breathing vertebrates, including lungfish, anuran amphibians, turtles, crocodiles and snakes, is characterized by brief periods of lung ventilation interspersed among apnoeas of variable duration. These intermittent ventilatory cycles are associated...

  20. Analysis of residual chlorine in simple drinking water distribution system with intermittent water supply

    Science.gov (United States)

    Goyal, Roopali V.; Patel, H. M.

    2015-09-01

    Knowledge of residual chlorine concentration at various locations in drinking water distribution system is essential final check to the quality of water supplied to the consumers. This paper presents a methodology to find out the residual chlorine concentration at various locations in simple branch network by integrating the hydraulic and water quality model using first-order chlorine decay equation with booster chlorination nodes for intermittent water supply. The explicit equations are developed to compute the residual chlorine in network with a long distribution pipe line at critical nodes. These equations are applicable to Indian conditions where intermittent water supply is the most common system of water supply. It is observed that in intermittent water supply, the residual chlorine at farthest node is sensitive to water supply hours and travelling time of chlorine. Thus, the travelling time of chlorine can be considered to justify the requirement of booster chlorination for intermittent water supply.