Measurement of ischaemia-reperfusion in patients with intermittent claudication using NMR-based metabonomics.

NARCIS (Netherlands)

Coolen, S.A.; Daykin, C.A.; Duynhoven, J.P. van; Dorsten, F.A. van; Wulfert, F.; Mathot, J.; Scheltinga, M.R.M.; Stroosma, O.; Vader, H.L.; Wijnen, M.H.W.A.

2008-01-01

Intermittent claudication has proved to be a good in vivo model for ischaemia-reperfusion. For assessment of ischaemia-reperfusion damage, the known biochemical markers all have disadvantages with respect to sensitivity and interference with other physiological events. In this work, we studied the

Analysis of isokinetic muscle function and postural control in individuals with intermittent claudication

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Morgan Lanzarin

2016-02-01

Full Text Available BACKGROUND: Intermittent claudication (IC is a debilitating condition that mostly affects elderly people. IC is manifested by a decrease in ambulatory function. Individuals with IC present with motor and sensory nerve dysfunction in the lower extremities, which may lead to deficits in balance. OBJECTIVE: This study aimed to measure postural control and isokinetic muscle function in individuals with intermittent claudication. METHOD: The study included 32 participants of both genders, 16 IC participants (mean age: 64 years, SD=6 and 16 healthy controls (mean age: 67 years, SD=5, which were allocated into two groups: intermittent claudication group (ICG and control group (CG. Postural control was assessed using the displacement and velocity of the center of pressure (COP during the sensory organization test (SOT and the motor control test (MCT. Muscle function of the flexor and extensor muscles of the knee and ankle was measured by an isokinetic dynamometer. Independent t tests were used to calculate the between-group differences. RESULTS: The ICG presented greater displacement (p =0.027 and speed (p =0.033 of the COP in the anteroposterior direction (COPap during the MCT, as well as longer latency (p =0.004. There were no between-group differences during the SOT. The ICG showed decreased muscle strength and power in the plantar flexors compared to the CG. CONCLUSION: Subjects with IC have lower values of strength and muscle power of plantiflexores, as well as changes in postural control in dynamic conditions. These individuals may be more vulnerable to falls than healthy subjects.

Fitting multistate transition models with autoregressive logistic regression : Supervised exercise in intermittent claudication

NARCIS (Netherlands)

de Vries, S O; Fidler, Vaclav; Kuipers, Wietze D; Hunink, Maria G M

1998-01-01

The purpose of this study was to develop a model that predicts the outcome of supervised exercise for intermittent claudication. The authors present an example of the use of autoregressive logistic regression for modeling observed longitudinal data. Data were collected from 329 participants in a

Gender and ethnic differences in arterial compliance in patients with intermittent claudication.

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Gardner, Andrew W; Montgomery, Polly S; Blevins, Steve M; Parker, Donald E

2010-03-01

To assess the gender and ethnic differences in arterial compliance in patients with intermittent claudication. A total of 114 patients participated, including 38 Caucasian men, 32 Caucasian women, 16 African American men, and 28 African American women. Patients were assessed on large artery elasticity index (LAEI), small artery elasticity index (SAEI), age, weight, body mass index, ankle-brachial index (ABI), smoking status, and metabolic syndrome components. Group differences were found for LAEI (P = .042), SAEI (P = .019), body mass index (P = .020), prevalence of elevated fasting glucose (P = .001), and prevalence of abdominal obesity (P = .025). Significant covariates for LAEI included age (P = .0002) and elevated triglycerides (P = .0719). LAEI (units = 10 mL x mm Hg) adjusted for age and triglycerides was 39% lower (P = .0005) in African Americans (11.4 +/- .90; mean +/- SE) than in Caucasians (15.8 +/- 0.72), whereas no significant difference (P = .7904) existed between men (13.8 +/- 0.81) and women (13.5 +/- 0.79). Significant covariates for SAEI included age (P = .0001), abdominal obesity (P = .0030), and elevated blood pressure (P = .0067). SAEI (units = 100 mL x mm Hg) adjusted for age, abdominal obesity, and elevated blood pressure was 32% lower (P = .0007) in African-Americans (2.8 +/- 0.3) than in Caucasians 4.1 +/- 0.2), and was 18% lower (P = .0442) in women (3.1 +/- 0.2) than in men (3.8 +/- 0.2). African American patients with intermittent claudication have more impaired macrovascular and microvascular function than Caucasian patients, and women have more impaired microvascular function than men. These ethnic and gender differences in arterial compliance are evident even though ABI was similar among groups, suggesting that arterial compliance provides unique information to quantify vascular impairment in patients with intermittent claudication.

Percutaneous transluminal angioplasty of infrarenal arteries in intermittent claudication

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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...

Improvement of walking distance by defibrotide in patients with intermittent claudication--results of a randomized, placebo-controlled study (the DICLIS study). Defibrotide Intermittent CLaudication Italian Study.

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Violi, F; Marubini, E; Coccheri, S; Nenci, G G

2000-05-01

Defibrotide is an antithrombotic drug which enhances prostacyclin production and activates fibrinolytic system. The aim of this study was to investigate the improvement of walking distance in patients with intermittent claudication treated with defibrotide. DICLIS was a double blind, placebo-controlled study which included patients with walking distance autonomy at a standardized treadmill test or =100 meters. A total of 310 patients were randomly allocated to placebo (n = 101), defibrotide 800 mg/day (n = 104) or defibrotide 1200 mg/day (n = 105). During a one year follow-up, the Absolute Walking Distance (AWD) was measured six times (0, 30, 60, 90, 180, 360 days). Similar improvement in walking distance was found in the three groups until the 90th day; thereafter placebo group showed no further increase, while AWD continued to increase in the defibrotide groups. Between the 180th and 360th day visits, AWD was significantly higher (P defibrotide than in patients given placebo. No difference in efficacy was observed between the two dosages of defibrotide. No differences in side effects were observed among the three groups. The results of the present trial suggest that long-term administration of defibrotide improves walking distance in patients with intermittent claudication.

Computerized dynamic posturography in the objective assessment of balance in patients with intermittent claudication.

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Mockford, Katherine A; Mazari, Fayyaz A K; Jordan, Alastair R; Vanicek, Natalie; Chetter, Ian C; Coughlin, Patrick A

2011-02-01

One-third of all elderly patients fall each year and impaired balance has been recognized as a specific risk factor. Intermittent claudication is common among the elderly population, affecting approximately 5% of the population over the age of 50. The aim of this proof-of-concept study was to assess the prevalence of impaired balance among elderly claudicants and to assess each patient's insight into their own risk of falling. A total of 58 claudicants (45 men), median age of 70 (interquartile range = 65-73) years, underwent objective balance assessment by using computerized dynamic posturography. As compared with 195 (5%) historic controls, 24 (41%) of the claudicants demonstrated abnormal balance when the Sensory Organization Test (SOT) was used. Vestibular dysfunction occurred in 52% of the claudicants. Abnormalities including somatosensory (22%), visual function (17%), and preferential reliance on inaccurate visual cues (17%) occurred less often. Prolonged Motor Control Test latency times were uncommon (n = 13) and were in most cases evenly distributed between those with normal (n = 7) and abnormal (n = 6) composite SOT scores. There was a significant difference in history of falling between claudicants with abnormal and normal SOT scores (p = 0.003), with a higher number of patients with abnormal SOT having experienced falling in the past year. However, no correlation between fear of falling and composite SOT score was found (Spearman rank correlation, r = 0.124; p = 0.381). Impaired balance, particularly secondary to vestibular problems, is very common among claudicants and may predispose to a high incidence of falls. Claudicants with abnormal balance are more likely to have a history of falls but not a fear of falling, thus potentially rendering these patients to be at a greater risk. Copyright © 2011. Published by Elsevier Inc.

[Consensus diagnosis and treatment of arterial intermittent claudication. Central Guidance Organization for Peer Review].

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Kitslaar, P J

1997-12-06

Intermittent claudication is an indicator of increased risk of cardiac and cerebrovascular morbidity and mortality and as such a reason to look for modifiable risk factors for atherosclerosis. A vascular anamnesis and physical examination can reliably exclude presence of peripheral arterial occlusive disease in the lower extremities, but cannot reliably demonstrate its presence. Certainty about presence or absence of peripheral arterial occlusive disease can be obtained by determination of an ankle-brachial blood pressure index. The main method for the diagnosis of severity and localisation of stenoses and occlusions in the arteries to the legs is the echo-Doppler (duplex) examination. With this method the feasibility of percutaneous transluminal angioplasty (PTA) can also be determined. Consequently, angiography has lost importance as a diagnostic method and is only still indicated as part of an interventional treatment (operation or PTA). Treatment should be aimed at both amelioration of symptoms and reduction of risk factors for atherosclerosis. A key-stone of the treatment is cessation of smoking. The role of pharmacotherapy in reducing symptomatology is only limited. Walking exercise can have a positive effect on walking distance and should always be tried. PTA is the treatment modality of first choice for stenoses in the aortoiliac and femoropopliteal arteries. For segmental occlusions in the iliac pathway, also recanalisation by means of PTA (in combination with stent placement) is a justifiable treatment option. In all other cases operative revascularisations give good functional results. Invasive treatments for patients with intermittent claudication should be performed within a multidisciplinary team.

The role of kinesitherapy and electrotherapeutic procedures in non-operative management of patients with intermittent claudications.

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Marković, Miroslav D; Marković, Danica M; Dragaš, Marko V; Končar, Igor B; Banzić, Igor L; Ille, Mihailo E; Davidović, Lazar B

2016-06-01

To examine the effects of physical therapy (kinesitherapy and electrotherapeutic procedures) on the course of peripheral arterial occlusive disease by monitoring the changes in values of claudication distance and ankle-brachial indexes. Prospective randomized study included 47 patients with peripheral arterial occlusive disease manifested by intermittent claudications associated with ankle-brachial indexes values ranging from 0.5 to 0.9. Patients from the first group (25 pts) were treated with medicamentous therapy, walking exercises beyond the pain threshold, dynamic low-burden kinesi exercises and electrotherapeutic ageneses (interference therapy, diadynamic therapy, and electromagnetic field), while the second group of patients (22 pts) was treated with "conventional" non-operative treatment - medicamentous therapy and walking exercises. The values of newly established absolute claudication distance and ankle-brachial indexes were measured. Significant increase of absolute claudication distance in both groups of patients was registered, independently of therapeutic protocol applied (p operative treatment of peripheral arterial occlusive disease patients, improving their functional ability and thus postponing surgical treatment. However, further investigations including larger number of patients are needed. © The Author(s) 2015.

Effectiveness of interspinous implant surgery in patients with intermittent neurogenic claudication: a systematic review and meta-analysis

NARCIS (Netherlands)

Moojen, W.A.; Arts, M.P.; Bartels, R.H.M.A.; Jacobs, W.C.; Peul, W.C.

2011-01-01

INTRODUCTION: Despite an increasing implantation rate of interspinous process distraction (IPD) devices in the treatment of intermittent neurogenic claudication (INC), definitive evidence on the clinical effectiveness of implants is lacking. The main objective of this review was to perform a

Intermittent claudication-like syndrome secondary to atherosclerosis in a yellow-naped Amazon parrot (Amazona ochrocephala auropalliata).

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Beaufrère, Hugues; Holder, Kali A; Bauer, Rudy; Schnellbacher, Rodney; Pariaut, Romain; Tully, Thomas N; Wakamatsu, Nobuko

2011-12-01

A 25-year-old yellow-naped Amazon parrot (Amazona ochrocephala auropalliata) was presented for nasal discharge and sneezing. Physical examination revealed poor feather quality, a mild serous nasal discharge, and a mass on the dorsal surface of the oral cavity. Cytologic examination of a mass aspirate as well as results of a choanal culture revealed squamous metaplasia of the salivary glands and bacterial rhinitis, respectively. Following resolution of the presenting conditions, the patient was presented for hind limb weakness and ataxia. The clinical signs were transient and generally resolved with rest but could be reproduced after stressful episodes, such as restraint for procedures or treatment. Test results from a complete blood count, biochemistry profile, whole-body radiographs, needle electromyography of the leg muscles, and an edrophonium challenge test were within reference limits. Based on the clinical signs and results of the diagnostic workup, the presumptive diagnosis was intermittent claudication, a condition caused by peripheral vascular disease and defined as intermittent weakness and pain in the legs induced by exercise and relieved by rest. Shortly after initiation of treatment with isoxsuprine, the bird died. Postmortem examination and histopathology revealed severe atherosclerotic lesions throughout the vascular system with stenotic lesions present in the abdominal aorta and femoral arteries. Electron microscopic examination of the great arteries was also performed and helped to further characterize the nature of the lesions. This case is the first report, to our knowledge, of an intermittent claudication-like syndrome associated with peripheral atherosclerosis in a psittacine bird. In addition, the distribution and some of the macroscopic and histopathologic features of the lesions differ from previous descriptions of atherosclerosis in psittacine birds.

Effectiveness of interspinous implant surgery in patients with intermittent neurogenic claudication : a systematic review and meta-analysis

NARCIS (Netherlands)

Moojen, Wouter A.; Arts, Mark P.; Bartels, Ronald H. M. A.; Jacobs, Wilco C. H.; Peul, Wilco C.

2011-01-01

Despite an increasing implantation rate of interspinous process distraction (IPD) devices in the treatment of intermittent neurogenic claudication (INC), definitive evidence on the clinical effectiveness of implants is lacking. The main objective of this review was to perform a meta-analysis of all

[The modern principles of management of intermittent claudication].

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Gamzatov, T H; Svetlikov, A V

2016-01-01

Number of patients with peripheral arterial disease, despite various national public health programs, remains high and has no steady downward trend over the past few decades. Despite recent advances in drug therapy, сonservative approach in the management of peripheral arterial disease is often neglected by vascular surgeons. However, vast majority of patients with intermittent claudication, who receive comprehensive conservative treatment, including risk factor modification, exercise and drug therapy, may get significant improvement in quality of life by partial or complete relief of symptoms related to the disease. Patients strictly adhering to medical recommendations has favorable prognosis and progression of disease to the stage of critical limb ischemia is very unlikely. Noncompliant patients and those who continue smoking in particular, often experience progression of symptoms related to the disease. That may result in the need for surgical intervention aiming to prevent or delay the onset of critical limb ischemia.

The reliability of differentiating neurogenic claudication from vascular claudication based on symptomatic presentation.

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Nadeau, Mélissa; Rosas-Arellano, M Patricia; Gurr, Kevin R; Bailey, Stewart I; Taylor, David C; Grewal, Ruby; Lawlor, D Kirk; Bailey, Chris S

2013-12-01

Intermittent claudication can be neurogenic or vascular. Physicians use a profile based on symptom attributes to differentiate the 2 types of claudication, and this guides their investigations for diagnosis of the underlying pathology. We evaluated the validity of these symptom attributes in differentiating neurogenic from vascular claudication. Patients with a diagnosis of lumbar spinal stenosis (LSS) or peripheral vascular disease (PVD) who reported claudication answered 14 questions characterizing their symptoms. We determined the sensitivity, specificity and positive and negative likelihood ratios (PLR and NLR) for neurogenic and vascular claudication for each symptom attribute. We studied 53 patients. The most sensitive symptom attribute to rule out LSS was the absence of "triggering of pain with standing alone" (sensitivity 0.97, NLR 0.050). Pain alleviators and symptom location data showed a weak clinical significance for LSS and PVD. Constellation of symptoms yielded the strongest associations: patients with a positive shopping cart sign whose symptoms were located above the knees, triggered with standing alone and relieved with sitting had a strong likelihood of neurogenic claudication (PLR 13). Patients with symptoms in the calf that were relieved with standing alone had a strong likelihood of vascular claudication (PLR 20.0). The classic symptom attributes used to differentiate neurogenic from vascular claudication are at best weakly valid independently. However, certain constellation of symptoms are much more indicative of etiology. These results can guide general practitioners in their evaluation of and investigation for claudication.

Effectiveness of interspinous implant surgery in patients with intermittent neurogenic claudication: a systematic review and meta-analysis

OpenAIRE

Moojen, Wouter A.; Arts, Mark P.; Bartels, Ronald H. M. A.; Jacobs, Wilco C. H.; Peul, Wilco C.

2011-01-01

Introduction Despite an increasing implantation rate of interspinous process distraction (IPD) devices in the treatment of intermittent neurogenic claudication (INC), definitive evidence on the clinical effectiveness of implants is lacking. The main objective of this review was to perform a meta-analysis of all systematic reviews, randomized clinical trials and prospective cohort series to quantify the effectiveness of IPDs and to evaluate the potential side-effects. Methods Data from all stu...

The management of patients with peripheral arterial disease and intermittent claudication. Actual recommendations.

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Tîrziu, Cristina; Bădilă, Elisabeta; Mehic, Florentina; Ghiorghe, S; Bartoş, Daniela

2010-01-01

In the general context of increasing prevalence of cardiovascular risk factors in European population, we face with a significant rise of the incidence of atherothrombotic diseases. Peripheral arterial disease (PAD) represented for a long time a peripheral interest for cardiologist. The epidemiological studies in the latest years determine a reconsideration of the medical attitude in respect of PAD, motivated by an increase in its prevalence and, on the other hand, by the significant cardiovascular risk this disease carries with. Taking into account that fact and aiming at a better medical approach of these patients, we realized a review regarding therapeutic methods in patients with PAD and intermittent claudication based on the latest medical publications and in accord with the guide in force at the moment.

The effects of acebutolol and metoprolol on walking distances and distal blood pressure in hypertensive patients with intermittent claudication

DEFF Research Database (Denmark)

Svendsen, T L; Jelnes, Rolf; Tønnesen, K H

1986-01-01

The effects of acebutolol (with intrinsic sympathomimetic activity (ISA] and metoprolol (without ISA) on arm blood pressure, ankle systolic blood pressure, claudication distances (CD) and maximal walking distances (MWD) were compared in patients with essential hypertension and intermittent...... claudication. Fourteen patients participated in a long-term, open, randomized cross-over study. After randomization the patients received either acebutolol, 200 mg b.i.d., or metoprolol, 100 mg b.i.d. After eight weeks the drugs were shifted and after another eight weeks they were withdrawn. Arm and ankle...... pressure there were no significant changes in ankle blood pressure, CD or MWD after the two drugs. After withdrawal of the drugs and after the arm blood pressure had returned to the control value no significant changes were seen in CD, MWD or ankle blood pressure. It is concluded that beta-blockers have...

The Felix-trial. Double-blind randomization of interspinous implant or bony decompression for treatment of spinal stenosis related intermittent neurogenic claudication

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Brand Ronald

2010-05-01

Full Text Available Abstract Background Decompressive laminotomy is the standard surgical procedure in the treatment of patients with canal stenosis related intermittent neurogenic claudication. New techniques, such as interspinous process implants, claim a shorter hospital stay, less post-operative pain and equal long-term functional outcome. A comparative (cost- effectiveness study has not been performed yet. This protocol describes the design of a randomized controlled trial (RCT on (cost- effectiveness of the use of interspinous process implants versus conventional decompression surgery in patients with lumbar spinal stenosis. Methods/Design Patients (age 40-85 presenting with intermittent neurogenic claudication due to lumbar spinal stenosis lasting more than 3 months refractory to conservative treatment, are included. Randomization into interspinous implant surgery versus bony decompression surgery will take place in the operating room after induction of anesthesia. The primary outcome measure is the functional assessment of the patient measured by the Zurich Claudication Questionnaire (ZCQ, at 8 weeks and 1 year after surgery. Other outcome parameters include perceived recovery, leg and back pain, incidence of re-operations, complications, quality of life, medical consumption, absenteeism and costs. The study is a randomized multi-institutional trial, in which two surgical techniques are compared in a parallel group design. Patients and research nurses are kept blinded of the allocated treatment during the follow-up period of 1 year. Discussion Currently decompressive laminotomy is the golden standard in the surgical treatment of lumbar spinal stenosis. Whether surgery with interspinous implants is a reasonable alternative can be determined by this trial. Trial register Dutch Trial register number: NTR1307

Effects of 12-week supervised treadmill training on spatio-temporal gait parameters in patients with claudication.

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Konik, Anita; Kuklewicz, Stanisław; Rosłoniec, Ewelina; Zając, Marcin; Spannbauer, Anna; Nowobilski, Roman; Mika, Piotr

2016-01-01

The purpose of the study was to evaluate selected temporal and spatial gait parameters in patients with intermittent claudication after completion of 12-week supervised treadmill walking training. The study included 36 patients (26 males and 10 females) aged: mean 64 (SD 7.7) with intermittent claudication. All patients were tested on treadmill (Gait Trainer, Biodex). Before the programme and after its completion, the following gait biomechanical parameters were tested: step length (cm), step cycle (cycle/s), leg support time (%), coefficient of step variation (%) as well as pain-free walking time (PFWT) and maximal walking time (MWT) were measured. Training was conducted in accordance with the current TASC II guidelines. After 12 weeks of training, patients showed significant change in gait biomechanics consisting in decreased frequency of step cycle (p gait was more regular, which was expressed via statistically significant decrease of coefficient of variation (p 0.05). Twelve-week treadmill walking training programme may lead to significant improvement of temporal and spatial gait parameters in patients with intermittent claudication. Twelve-week treadmill walking training programme may lead to significant improvement of pain-free walking time and maximum walking time in patients with intermittent claudication.

Subanalysis of the CONFIRM Registries: Acute Procedural Outcomes in Claudicant and Critical Limb Ischemia Patients With Varying Levels of Calcification Treated for Peripheral Arterial Disease With Orbital Atherectomy.

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Adams, George L; Das, Tony; Lee, Michael S; Beasley, Robert; Mustapha, Jihad

2015-11-01

Patients with peripheral arterial disease (PAD) can be classified into groups based upon the severity of the disease using the Rutherford classification system. This analysis compares the procedural outcomes of PAD patients treated with orbital atherectomy stratified by Rutherford class (1-3 = intermittent claudication; 4-6 = critical limb ischemia [CLI]), and acute angiographic outcomes of these patients stratified by degree of lesion calcification. The CONFIRM registry series was analyzed and included 1697 patients with intermittent claudication (Rutherford class 1-3) and 1320 patients with CLI (Rutherford class 4-6) treated with orbital atherectomy. The composite rate of dissection, perforation, slow-flow, vessel closure, spasm, embolism, and thrombus formation was compared between claudicants and CLI patients with varying degrees of lesion calcification. Patients with CLI were older and had a higher prevalence of diabetes, coronary artery disease, and renal disease (Patherectomy resulted in similar low procedural complication rates in the CLI group compared with the claudicant group. These results suggest that orbital atherectomy is safe and effective for treating calcified lesions in high-risk patients with varying severity of PAD symptoms.

Compared to Intermittant Claudication Critical Limb Ischemia Is Associated with Elevated Levels of Cytokines.

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Juho Jalkanen

Full Text Available Critical limb ischemia (CLI is the advanced stage of peripheral artery disease (PAD and associated with an extremely poor clinical outcome. In order to understand the possible role of circulating cytokines and poor outcome associated with CLI we compared the circulating cytokine profile of patients with CLI against patients with intermittent claudication (IC. The levels of 48 circulating cytokines were examined in 226 consecutive patients with peripheral artery disease (PAD admitted for elective, non-urgent, invasive treatment of IC or CLI. The PAD patient cohort was evenly distributed between subjects with IC (46.5% and CLI (53.5%. As accustomed in PAD, CLI was associated with higher age, chronic kidney disease and diabetes when compared to IC (P < 0.01 for all. In multivariable linear regression modeling taking into account the baseline differences between IC and CLI groups CLI was independently associated with elevated levels of a large number of cytokines: IL-1β, IL-1ra, IL-2Rα, IL-4, IL-6, IL-10, IFN-γ, GM-CSF, G-CSF (P < 0.01 for all, and IL-2, IL-7, IL-12, IL-13, IL-17, bFGF, VEGF, SCGF-β (P < 0.05 for all. The current findings indicate that CLI is associated with a circulating cytokine profile, which resembles serious medical conditions such as severe pancreatitis, sepsis, or even cancer. Compared to IC, CLI is a systemic inflammatory condition, which may explain the extremely poor outcome associated with it.

The ClaudicatioNet concept: design of a national integrated care network providing active and healthy aging for patients with intermittent claudication

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Lauret GJ

2012-08-01

Full Text Available Gert-Jan Lauret,1,2 Harm JH Gijsbers,3 Erik JM Hendriks,2 Marie-Louise Bartelink,4 Rob A de Bie,2 Joep AW Teijink1,2 On behalf of the ClaudicatioNet Study Group members1Department of Vascular Surgery, Catharina Hospital, Eindhoven, The Netherlands; 2Caphri Research Institute, Department of Epidemiology, Maastricht University, Maastricht, The Netherlands; 3Dutch Society for Heart, Vascular and Lung Physiotherapy, Meijerslaan PG Heemstede, The Netherlands; 4Julius Center Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The NetherlandsIntroduction: Intermittent claudication (IC is a manifestation of peripheral arterial occlusive disease (PAOD. Besides cardiovascular risk management, supervised exercise therapy (SET should be offered to all patients with IC. Outdated guidelines, an insufficient number of specialized physiotherapists (PTs, lack of awareness of the importance of SET by referring physicians, and misguided financial incentives all seriously impede the availability of a structured SET program in The Netherlands.Description of care practice: By initiating regional care networks, ClaudicatioNet aims to improve the quality of care for patients with IC. Based on the chronic care model as a conceptual framework, these networks should enhance the access, continuity, and (cost efficiency of the health care system. With the aid of a national database, health care professionals will be able to benchmark patient results while ClaudicatioNet will be able to monitor quality of care by way of functional and patient reported outcome measures.Discussion: The success of ClaudicatioNet is dependent on several factors. Vascular surgeons, general practitioners and coordinating central caregivers will need to team up and work in close collaboration with specialized PTs. A substantial task in the upcoming years will be to monitor the quality, volume, and distribution of ClaudicatioNet PTs. Finally, misguided financial incentives

Iliac Artery Stent Placement Relieves Claudication in Patients with Iliac and Superficial Femoral Artery Lesions

International Nuclear Information System (INIS)

Ichihashi, Shigeo; Higashiura, Wataru; Itoh, Hirofumi; Sakaguchi, Shoji; Kichikawa, Kimihiko

2013-01-01

Purpose. To evaluate the efficacy of iliac artery stent placement for relief of claudication in patients with both iliac and superficial femoral artery (SFA) lesions. Methods. Stent placement for only iliac artery occlusive disease was performed in 94 limbs (74 patients) with both iliac and SFA occlusive disease on the same limb. All procedures were performed because intermittent claudication did not improve after continuation of antiplatelet medication therapy and home-based exercise for 3 months. Rutherford classification was 2 in 20 limbs and 3 in 74 limbs. Patients with critical limb ischemia were excluded. Median duration of follow-up was 40 months. Primary patency rates of the iliac stent, clinical improvement rates, and risk factors for requiring additional SFA procedures were evaluated. Results. Primary patency rates of the iliac stent at 1, 3, 5, and 7 years were 97, 93, 79, and 79 %, respectively. The initial clinical improvement rate was 87 %. Continued clinical improvement rates at 1, 3, 5, and 7 years were 87, 81, 69, and 66 %, respectively. SFA Trans-Atlantic Inter-Society Consensus (TASC) II C/D lesion was a significant risk factor for requiring additional SFA procedures. Conclusion. Intermittent claudication was relieved by iliac stent placement in most patients with both iliac and SFA lesions. Thus, the indications for treatment of the SFA intended for claudicants should be evaluated after treatment of the iliac lesion.

Imaging popliteal artery disease in young adults with claudication: self-assessment module.

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Chew, Felix S; Bui-Mansfield, Liem T

2007-09-01

The educational objectives of this self-assessment module on imaging popliteal artery disease in young adults with intermittent claudication are for the participant to exercise, self-assess, and improve his or her knowledge of the imaging and clinical features of popliteal artery entrapment syndrome, cystic adventitial disease,and masses associated with popliteal artery obstruction.

Exploring physical activity behaviour - needs for and interest in a technology-delivered, home-based exercise programme among patients with intermittent claudication.

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Cornelis, Nils; Buys, Roselien; Fourneau, Inge; Dewit, Tijl; Cornelissen, Véronique

2018-02-01

Supervised walking is a first line therapy in peripheral arterial disease (PAD) with complaints of intermittent claudication. However, uptake of supervised programmes is low. Home-based exercise seems an appealing alternative; especially since technological advances, such as tele-coaching and tele-monitoring, may facilitate the process and support patients when adopting a physically active lifestyle. To guide the development of such an intervention, it is important to identify barriers of physical activity and the needs and interests for technology-enabled exercise in this patient group. PAD patients were recruited at the vascular centre of UZ Leuven (Belgium). A questionnaire assessing PA (SF-International Physical Activity Questionnaire), barriers to PA, and interest in technology-supported exercise (Technology Usage Questionnaire) was completed. Descriptive and correlation analyses were performed. Ninety-nine patients (76 men; mean age 69 years) completed the survey. Physical activity levels were low in 48 %, moderate in 29 %, and high in 23 %. Intermittent claudication itself is the most important barrier for enhanced PA, with most patients reporting pain (93 %), need for rest (92 %), and obstacles worsening their pain (74 %) as barriers. A total of 93 % participants owned a mobile phone; 76 % had Internet access. Eighty-seven reported the need for an exercise programme, with 67 % showing interest in tele-coaching to support exercise. If technology was available, three-quarter stated they would be interested in home-based tele-coaching using the Internet (preferably e-mails, 86 %); 50 % via mobile phone, 87 % preferred text messages. Both were inversely related to age (rpb = 0.363 and rpb = 0.255, p < 0.05). Acquaintance with elastic bands or gaming platforms was moderate (55 and 49 %, respectively), but patients were interested in using them as alternatives (84 and 42 %). Interest in platforms was age-dependent (rs = -0.508, p < 0.01). PAD patients show

Effects of walking and strength training on walking capacity in individuals with claudication: meta-analysis

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Alessandra de Souza Miranda

2013-06-01

Full Text Available CONTEXT: Over the past few years, several clinical trials have been performed to analyze the effects of exercise training on walking ability in patients with intermittent claudication (IC. However, it remains unclear which type of physical exercise provides the maximum benefits in terms of walking ability. OBJECTIVE: To analyze, by means of a meta-analysis, the effects of walking and strength training on the walking capacity in patients with IC. METHODS: Papers analyzing the effects of walking and strength training programs in patients with IC were browsed on the Medline, Lilacs, and Cochrane databases. Randomized clinical trials scoring >4 on the Physiotherapy Evidence Database (PEDro scale and assessing claudication distance (CD and total walking distance (TWD were included in the review. RESULTS: Walking and strength training yielded increases in CD and TWD (P < 0.05. However, walking training yielded greater increases than strength training (P = 0.02. CONCLUSION: Walking and strength training improve walking capacity in patients with IC. However, greater improvements in TWD are obtained with walking training.

Supervised Exercise Therapy for Intermittent Claudication Is Increasingly Endorsed by Dutch Vascular Surgeons.

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Hageman, David; Lauret, Gert-Jan; Gommans, Lindy N M; Koelemay, Mark J W; van Sambeek, Marc R H M; Scheltinga, Marc R M; Teijink, Joep A W

2018-02-01

Although supervised exercise therapy (SET) is generally accepted as an effective noninvasive treatment for intermittent claudication (IC), Dutch vascular surgeons were initially somewhat hesitant as reported by a 2011 questionnaire study. Later on, a nationwide multidisciplinary network for SET was introduced in the Netherlands. The aim of this questionnaire study was to determine possible trends in conceptions among Dutch vascular surgeons regarding the prescription of SET. In the year of 2015, Dutch vascular surgeons, fellows, and senior residents were asked to complete a 26-item questionnaire including issues that were considered relevant for prescribing SET such as patient selection criteria and comorbidity. Outcome was compared to the 2011 survey. Data of 124 respondents (82% males; mean age 46 years; 64% response rate) were analyzed. SET referral rate of new IC patients was not different over time (2015: 81% vs. 2011: 75%; P = 0.295). However, respondents were more willing to prescribe SET in IC patients with chronic obstructive pulmonary disease (2015: 86% vs. 2011: 69%; P = 0.002). Nevertheless, a smaller portion of respondents found that SET was also indicated for aortoiliac disease (2015: 63% vs. 2011: 76%; P = 0.049). Insufficient health insurance coverage and/or personal financial resources were the most important presumed barriers preventing patients from initiating SET (80% of respondents). Moreover, 94% of respondents judged that SET should be fully reimbursed by all Dutch basic health insurances. The concept of SET for IC is nowadays generally embraced by the vast majority of Dutch vascular surgeons. SET may have gained in popularity in IC patients with cardiopulmonary comorbidity. However, SET remains underutilized for aortoiliac disease. Reimbursement is considered crucial for a successful SET implementation. Copyright © 2017 Elsevier Inc. All rights reserved.

The ClaudicatioNet concept: design of a national integrated care network providing active and healthy aging for patients with intermittent claudication.

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Lauret, Gert-Jan; Gijsbers, Harm J H; Hendriks, Erik J M; Bartelink, Marie-Louise; de Bie, Rob A; Teijink, Joep A W

2012-01-01

Intermittent claudication (IC) is a manifestation of peripheral arterial occlusive disease (PAOD). Besides cardiovascular risk management, supervised exercise therapy (SET) should be offered to all patients with IC. Outdated guidelines, an insufficient number of specialized physiotherapists (PTs), lack of awareness of the importance of SET by referring physicians, and misguided financial incentives all seriously impede the availability of a structured SET program in The Netherlands. By initiating regional care networks, ClaudicatioNet aims to improve the quality of care for patients with IC. Based on the chronic care model as a conceptual framework, these networks should enhance the access, continuity, and (cost) efficiency of the health care system. With the aid of a national database, health care professionals will be able to benchmark patient results while ClaudicatioNet will be able to monitor quality of care by way of functional and patient reported outcome measures. The success of ClaudicatioNet is dependent on several factors. Vascular surgeons, general practitioners and coordinating central caregivers will need to team up and work in close collaboration with specialized PTs. A substantial task in the upcoming years will be to monitor the quality, volume, and distribution of ClaudicatioNet PTs. Finally, misguided financial incentives within the Dutch health care system need to be tackled. With ClaudicatioNet, integrated care pathways are likely to improve in the upcoming years. This should result in the achievement of optimal quality of care for all patients with IC.

Effect of diabetes mellitus on walking distance parameters after supervised exercise therapy for intermittent claudication: A systematic review.

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Hageman, David; Gommans, Lindy Nm; Scheltinga, Marc Rm; Teijink, Joep Aw

2017-02-01

Some believe that certain patients with intermittent claudication may be unsuitable for supervised exercise therapy (SET), based on the presence of comorbidities and the possibly increased risks. We conducted a systematic review (MEDLINE, EMBASE and CENTRAL) to summarize evidence on the potential influence of diabetes mellitus (DM) on the response to SET. Randomized and nonrandomized studies that investigated the effect of DM on walking distance after SET in patients with IC were included. Considered outcome measures were maximal, pain-free and functional walking distance (MWD, PFWD and FWD). Three articles met the inclusion criteria ( n = 845). In one study, MWD was 111 meters (128%) longer in the non-DM group compared to the DM group after 3 months of follow-up ( p = 0.056). In a second study, the non-DM group demonstrated a significant increase in PFWD (114 meters, p ⩽ 0.05) after 3 months of follow-up, whereas there was no statistically significant increase for the DM group (54 meters). On the contrary, the largest study of this review did not demonstrate any adverse effect of DM on MWD and FWD after SET. In conclusion, the data evaluating the effects of DM on SET were inadequate to determine if DM impairs the exercise response. While trends in the data do not suggest an impairment, they are not conclusive. Practitioners should consider this limitation when making clinical decisions.

Intermittent, Non Cyclic Severe Mechanical Aortic Valve Regurgitation

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Choi, Jong Hyun; Song, Seunghwan; Lee, Myung-Yong

2013-01-01

Mechanical aortic prosthesis dysfunction can result from thrombosis or pannus formation. We describe an unusual case of intermittent, non cyclic mechanical aortic prosthesis dysfunction due to pannus formation with thrombus in the absence of systolic restriction of disk excursion, that presented with intermittent severe aortic regurgitation. PMID:24459568

Education and home based training for intermittent claudication: functional effects and quality of life.

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Prévost, Alain; Lafitte, Marianne; Pucheu, Yann; Couffinhal, Thierry

2015-03-01

Supervised exercise programs increase physical performance in patients with peripheral artery disease (PAD). However, there are a limited number of programs, and to date they have failed to provide evidence of long-term adherence to exercise or any meaningful effect on Quality of Life (QoL). We created a program of therapeutic education and a personalized program of reconditioning exercise for patients with PAD. Patients with an ankle-brachial index (ABI) below 0.9 in at least one limb, and an absolute claudication distance (ACD) ≤500 meters, were included in the study. Quality of Life (QoL) as measured by SF-36, cardiovascular risk factors and functional parameters were evaluated at 0, 3, 6 and 12 months. Forty-six patients completed the program. Cardiovascular risks were controlled and stabilized over time. SF-36 scores improved significantly and remained stable. Initial and absolute claudication distance (ICD and ACD) as well as other functional parameters improved significantly (6 months: +138 m or +203% ICD and +139 m or +84% ACD). Ten patients (22%) did not show improvement in ICD or ACD within the first 3 months, but their SF-36 score did increase at subsequent visits. Interestingly, these patients had a significantly lower ACD at baseline. This study measured beneficial effects of an educational therapeutic program for patients with PAD. The results demonstrate a significant improvement in functional and QoL parameters during the first 3 months of coaching, and long-term persistence of the results even when patients were no longer coached. © The European Society of Cardiology 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Self-administered versus interview-based questionnaires among patients with intermittent claudication: Do they give different results? A cross-sectional study.

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Lozano, Francisco; Lobos, José María; March, José Ramón; Carrasco, Eduardo; Barros, Marcello Barbosa; González-Porras, José Ramón

2016-01-01

Many clinical investigations use generic and/or specific questionnaires to obtain information about participants and patients. There is disagreement about whether the administration method can affect the results. The aim here was to determine whether, among patients with intermittent claudication (IC), there are differences in the Walking Impairment Questionnaire (WIQ) and European Quality of Life-5 Dimension (EQ-5D) scores with regard to: 1) the questionnaire administration method (self-administration versus face-to-face interview); and 2) the type of interviewer (vascular surgeon, VS, versus general practitioner, GP). Cross-sectional observational multicenter epidemiological study carried out within the Spanish National Health Service. 1,641 evaluable patients with IC firstly completed the WIQ and EQ-5D questionnaires and then were interviewed by their doctor on the same day. Pearson correlations and Chi-square tests were used. There was a strong correlation (r > 0.800; P questionnaires, and between the VS and GP groups. Likewise, there was a high level of concordance (P > 0.05) between the different dimensions of the WIQ-distance and EQ-5D (self-administration versus face-to-face) in the VS and GP groups. There was no difference between the different methods of administering the WIQ and EQ-5D questionnaires, among the patients with IC. Similarly, the two types of interviewers (VS or GP) were equally valid. Therefore, it seems unnecessary to expend effort to administer these questionnaires by interview, in studies on IC.

Google Maps offers a new way to evaluate claudication.

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Khambati, Husain; Boles, Kim; Jetty, Prasad

2017-05-01

Accurate determination of walking capacity is important for the clinical diagnosis and management plan for patients with peripheral arterial disease. The current "gold standard" of measurement is walking distance on a treadmill. However, treadmill testing is not always reflective of the patient's natural walking conditions, and it may not be fully accessible in every vascular clinic. The objective of this study was to determine whether Google Maps, the readily available GPS-based mapping tool, offers an accurate and accessible method of evaluating walking distances in vascular claudication patients. Patients presenting to the outpatient vascular surgery clinic between November 2013 and April 2014 at the Ottawa Hospital with vasculogenic calf, buttock, and thigh claudication symptoms were identified and prospectively enrolled in our study. Onset of claudication symptoms and maximal walking distance (MWD) were evaluated using four tools: history; Walking Impairment Questionnaire (WIQ), a validated claudication survey; Google Maps distance calculator (patients were asked to report their daily walking routes on the Google Maps-based tool runningmap.com, and walking distances were calculated accordingly); and treadmill testing for onset of symptoms and MWD, recorded in a double-blinded fashion. Fifteen patients were recruited for the study. Determination of walking distances using Google Maps proved to be more accurate than by both clinical history and WIQ, correlating highly with the gold standard of treadmill testing for both claudication onset (r = .805; P Google Maps tool was also efficient, with reporting times averaging below 4 minutes. For vascular claudicants with no other walking limitations, Google Maps is a promising new tool that combines the objective strengths of the treadmill test and incorporates real-world walking environments. It offers an accurate, efficient, inexpensive, and readily accessible way to assess walking distances in patients with

Optimization, ex vivo permeation, and stability study of lipid nanocarrier loaded gelatin capsules for treatment of intermittent claudication

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Sallam MA

2015-07-01

Full Text Available Marwa Ahmed Sallam,1 María Teresa Marín Boscá21Department of Industrial Pharmacy, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt; 2Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, Granada University, Granada, Spain Abstract: In this study, an optimized nanodispersible oral dosage form (containing a lactate ester was developed for cilostazol (CZL. CZL is a phosphodiesterase inhibitor used for intermittent claudication. We aimed to improve the dissolution rate and absorption of CZL giving it a better chance of oral bioavailability, and to evaluate its stability on storage. Suitable compositions of nanoemulsion preconcentrate formulations were screened via solubility and compatibility tests. Response surface methodology and a desirability approach were applied to optimize preconcentrates containing minimum amount of surfactant mixture, maximum amount of lipid, and possessing the smallest globule size, with the highest emulsification and dissolution rates and minimum risk of drug precipitation. As part of the optimization process, the main effect, interaction effects and quadratic effects of amounts of lipid, and surfactant/co-surfactant ratio on % transmittance, globule size, emulsification time, drug precipitation, and drug release were investigated. The optimized formulation consisting of 28.9% butyl lactate, 28.9% Capryol®, 27.82% Solubilisant Gamma® 2429, and 14.18% Transcutol® possessing a globule size of 60 nm was mixed with Aerosil® 200. This gave uniform free flowing granules, which were characterized for surface and powder properties. The self-nanoemulsifying granules (SNEGs filled into hard gelatin capsules showed two- and threefold increase in CZL released compared with conventional tablet and pure drug, respectively. The amount of drug permeated using non-everted sac technique from the SNEGs was twofold higher than that permeated from the tablet suspension. The shelf life was 526 days at

Home-based exercise for elderly patients with intermittent claudication limited by osteoarticular disorders - feasibility and effectiveness of a low-intensity programme.

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Lamberti, Nicola; Straudi, Sofia; Lissia, Efisio; Cavazzini, Lorenza; Buja, Sergio; Manfredini, Roberto; Basaglia, Nino; Manfredini, Fabio

2018-04-01

Peripheral arterial disease (PAD) is a common cardiovascular pathology affecting mobility in elderly. Osteoarticular diseases (ODs), responsible for functional limitations and confounding leg symptoms, may interfere with exercise therapy. This study evaluates the feasibility and effectiveness of a structured home-based exercise programme on rehabilitative outcomes in a cohort of elderly PAD patients with and without coexisting ODs. Patients were enrolled from 2002 to 2016 in an exercise programme prescribed and controlled at the hospital and based on two daily 10-minute home walking sessions below the self-selected speed. The presence and localization of ODs at baseline were derived from consultation of medical documents. The ankle-brachial index and functional outcomes, defined as speed at the onset of claudication and attainable maximal speed by an incremental treadmill test, were assessed at baseline and discharge. Feasibility was determined according to dropout rate, number of visits, duration of the programme, and adherence. A total of 1,251 PAD patients were enrolled (931 men; 71 ± 9 years; 0.63 ± 0.19 ankle-brachial index). Eight hundred sixty-four patients were free of ODs (ODfree PAD , 69 %), whereas 387 were affected by ODs (OD PAD , 31 %), predominantly located in the spine (72 %). In the logistic regression models, the presence of ODs was associated with female sex, overweight, sedentary and/or driving professions. At discharge, OD PAD and ODfree PAD did not differ in dropout rates (12 % each), programme duration (378 ± 241 vs. 390 ± 260 days), number of visits (7 ± 3 each), and adherence (80 % each). Similar improvements for OD PAD and ODfree PAD were observed for the ankle-brachial index (0.06 ± 0.12 each), the speed at onset of claudication (0.7 ± 0.7 vs. 0.7 ± 0.8 kmh-1; p = 0.70), and maximal speed (0.4 ± 0.6 vs. 0.4 ± 0.6 kmh-1; p = 0.77). Equally satisfactory rehabilitative outcomes were observed in elderly patients with claudication

A Primary Care Approach to the Diagnosis and Management of Peripheral Arterial Disease

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Dawson, David L.

2000-01-01

The objectives of this work are: (1) Be able to recognize characteristic symptoms of intermittent claudication (2) Diagnose PAD on the basis of history, physical exam, and simple limb blood pressure measurements (3) Recognize the significance of peripheral artery disease as a marker for coronary or cerebrovascular atherosclerosis (4) Provide appropriate medical management of atherosclerosis risk factors-- including use of antiplatelet therapy to reduce risk of myocardial infarction, stroke and death (5) Manage symptoms of intermittent claudication with program of smoking cessation, exercise, and medication The diagnosis of intermittent claudication secondary to peripheral artery disease (PAD) can often be made on the basis of history and physical examination. Additional evaluation of PAD is multi-modal and the techniques used will vary depending on the nature and severity of the patient's presenting problem. Most patients can be appropriately managed without referral for specialized diagnostic services or interventions.

Popliteal amyloidoma presenting with leg ischemia in a chronic dialysis patient

International Nuclear Information System (INIS)

Aoki, Y.; Kaneda, Kiyoshi; Miyagi, Noboru; Itoh, Manabu; Ohmoto, Hirofumi

2000-01-01

The authors report a case of bilateral popliteal amyloidoma causing stenosis of the popliteal artery and vein. This patient had been treated with hemodialysis for 26 years. The diagnosis was made with MR angiography. A popliteal tumor of the right knee was resected surgically and the histologic examination showed deposition of amyloid. After resecting the popliteal tumor, the severe leg pain and intermittent claudication improved. This report suggests that popliteal amyloid tumors should be considered in a patient undergoing long-term hemodialysis who complains of leg pain and intermittent claudication. (orig.)

Introducing the Concept of the Minimally Important Difference to Determine a Clinically Relevant Change on Patient-Reported Outcome Measures in Patients with Intermittent Claudication

International Nuclear Information System (INIS)

Conijn, Anne P.; Jonkers, Wilma; Rouwet, Ellen V.; Vahl, Anco C.; Reekers, Jim A.; Koelemay, Mark J. W.

2015-01-01

PurposeThe minimally important difference (MID) represents the smallest change in score on patient-reported outcome measures that is relevant to patients. The aim of this study was to introduce the MID for the Vascular Quality of Life Questionnaire (VascuQol) and the walking impairment questionnaire (WIQ) for patients with intermittent claudication (IC).MethodsIn this multicenter study, we recruited 294 patients with IC between July and October 2012. Patients completed the VascuQol, with scores ranging from 1 to 7 (worst to best), and the WIQ, with scores ranging from 0 to 1 (worst to best) at first visit and after 4 months follow-up. In addition, patients answered an anchor-question rating their health status compared to baseline, as being improved, unchanged, or deteriorated. The MID for improvement and deterioration was calculated by an anchor-based approach, and determined with the upper and lower limits of the 95 % confidence interval of the mean change of the group who had not changed according to the anchor-question.ResultsFor the MID analyses of the VascuQol and WIQ, 163 and 134 patients were included, respectively. The MID values for the VascuQol (mean baseline score 4.25) were 0.87 for improvement and 0.23 for deterioration. For the WIQ (mean baseline score 0.39), we found MID values of 0.11 and −0.03 for improvement and deterioration, respectively.ConclusionIn this study, we calculated the MID for the VascuQol and the WIQ. Applying these MID facilitates better interpretation of treatment outcomes and can help to set treatment goals for individual care

Introducing the Concept of the Minimally Important Difference to Determine a Clinically Relevant Change on Patient-Reported Outcome Measures in Patients with Intermittent Claudication

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Conijn, Anne P., E-mail: a.p.conijn@amc.nl [Academic Medical Center, Departments of Vascular Surgery and Interventional Radiology (Netherlands); Jonkers, Wilma, E-mail: wilma.jonkers@achmea.nl [Achmea Insurances, Division of Health Care (Netherlands); Rouwet, Ellen V., E-mail: e.rouwet@erasmusmc.nl [Erasmus Medical Center, Department of Vascular Surgery (Netherlands); Vahl, Anco C., E-mail: a.c.vahl@olvg.nl [Onze Lieve Vrouwe Gasthuis, Department of Vascular Surgery (Netherlands); Reekers, Jim A., E-mail: j.a.reekers@amc.nl [Academic Medical Center, Department of Radiology (Netherlands); Koelemay, Mark J. W., E-mail: m.j.koelemaij@amc.nl [Academic Medical Center, Department of vascular surgery (Netherlands)

2015-10-15

PurposeThe minimally important difference (MID) represents the smallest change in score on patient-reported outcome measures that is relevant to patients. The aim of this study was to introduce the MID for the Vascular Quality of Life Questionnaire (VascuQol) and the walking impairment questionnaire (WIQ) for patients with intermittent claudication (IC).MethodsIn this multicenter study, we recruited 294 patients with IC between July and October 2012. Patients completed the VascuQol, with scores ranging from 1 to 7 (worst to best), and the WIQ, with scores ranging from 0 to 1 (worst to best) at first visit and after 4 months follow-up. In addition, patients answered an anchor-question rating their health status compared to baseline, as being improved, unchanged, or deteriorated. The MID for improvement and deterioration was calculated by an anchor-based approach, and determined with the upper and lower limits of the 95 % confidence interval of the mean change of the group who had not changed according to the anchor-question.ResultsFor the MID analyses of the VascuQol and WIQ, 163 and 134 patients were included, respectively. The MID values for the VascuQol (mean baseline score 4.25) were 0.87 for improvement and 0.23 for deterioration. For the WIQ (mean baseline score 0.39), we found MID values of 0.11 and −0.03 for improvement and deterioration, respectively.ConclusionIn this study, we calculated the MID for the VascuQol and the WIQ. Applying these MID facilitates better interpretation of treatment outcomes and can help to set treatment goals for individual care.

Relacao entre o nivel de atividade fisica estimado pelo Baltimore Activity Scale for Intermittent Claudication e a pedometria em pacientes com claudicacao intermitente

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Pollianny Ramos Lopes

2013-09-01

Full Text Available CONTEXTO: Os pacientes com claudicação intermitente apresentam níveis reduzidos de atividade física. A Baltimore Activity Scale for Intermittent Claudication (BASIC foi validada para quantificar o nível de atividade física destes pacientes. No entanto, esta validação se baseou em apenas dois dias de monitoramento com acelerômetros, de modo que ainda permanece incerto se a BASIC fornece informações sobre os níveis de atividade física semanal. OBJETIVO: Analisar a correlação entre o nível de atividade física estimada pela BASIC e o nível obtido pelo pedômetro em uma semana, em pacientes com claudicação intermitente. MÉTODOS: Foram estudados 150 pacientes com claudicação intermitente, com idade entre 30 e 80 anos. Foram obtidos os dados sociodemográficos e verificada a presença de comorbidades e de fatores de risco cardiovascular, e a BASIC. O pedômetro foi utilizado por sete dias consecutivos, sendo a análise feita em três diferentes períodos de monitorização (todos os dias, dias da semana e do fim de semana. RESULTADOS: Foi observada correlação entre a BASIC e a média de passos de todos os dias (rho=0,343; p<0,001, dos dias de semana (rho=0,336; p<0,001 e dos dias do final de semana (rho=0,317; p<0,001. CONCLUSÃO: Em pacientes com claudicação intermitente, o nível de atividade física estimado pela BASIC se correlaciona com o nível de atividade física semanal.

Sciatica and claudication caused by ganglion cyst.

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Yang, Guang; Wen, Xiaoyu; Gong, Yubao; Yang, Chen

2013-12-15

Case report. We report a rare case that a ganglion cyst compressed the sciatic nerve and caused sciatica and claudication in a 51-year-old male. Sciatica and claudication commonly occurs in spinal stenosis. To our knowledge, only 4 cases have been reported on sciatica resulting from posterior ganglion cyst of hip. A 51-year-old male had a 2-month history of radiating pain on his right leg. He could only walk 20 to 30 m before stopping and standing to rest for 1 to 3 minutes. Interestingly, he was able to walk longer distances (about 200 m) when walking slowly in small steps, without any rest. He had been treated as a case of lumbar disc herniation, but conservative treatment was ineffective. On buttock examination, a round, hard, and fixative mass was palpated at the exit of the sciatic nerve. MR imaging of hip revealed a multilocular cystic mass located on the posterior aspect of the superior gemellus and obturator internus, compressing the sciatic nerve. On operation, we found that the cyst extended to the superior gemellus and the obturator internus, positioned right at the outlet of the sciatic nerve. At 18 months of follow-up, the patient continued to be symptom free. He returned to comprehensive physical activity with no limitations. For an extraspinal source, a direct compression on the sciatic nerve also resulted in sciatica and claudication. A meticulous physical examination is very important for the differential diagnosis of extraspinal sciatica from spinal sciatica.

A Three Month Home Exercise Programme Augmented with Nordic Poles for Patients with Intermittent Claudication Enhances Quality of Life and Continues to Improve Walking Distance and Compliance After One Year.

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Oakley, C; Spafford, C; Beard, J D

2017-05-01

The objective of this study was to collect 1 year follow-up information on walking distance, speed, compliance, and cost in patients with intermittent claudication who took part in a previously reported 12 week randomised clinical trial of a home exercise programme augmented with Nordic pole walking versus controls who walked normally. A second objective was to look at quality of life and ankle brachial pressure indices (ABPIs) after a 12 week augmented home exercise programme. Thirty-two of the 38 patients who completed the original trial were followed-up after 6 and 12 months. Frequency, duration, speed, and distance of walking were recorded using diaries and pedometers. A new observational cohort of 29 patients was recruited to the same augmented home exercise programme. ABPIs, walking improvement, and quality of life questionnaire were recorded at baseline and 12 weeks (end of the programme). Both groups in the follow-up study continued to improve their walking distance and speed over the following year. Compliance was excellent: 98% of the augmented group were still walking with poles at both 6 and 12 months, while 74% of the control group were still walking at the same point. The augmented group increased their mean walking distance to 17.5 km by 12 months, with a mean speed of 4.2 km/hour. The control group only increased their mean walking distance from 4.2 km to 5.6 km, and speed to 3.3 km/hour. Repeated ANOVA showed the results to be highly significant (p = .002). The 21/29 patients who completed the observational study showed a statistically significant increase in resting ABPIs from baseline (mean ± SD 0.75 ± 0.12) to week 12 (mean ± SD 0.85 ± 0.12) (t = (20) -8.89, p = .000 [two-tailed]). All their walking improvement and quality of life parameters improved significantly (p = .002 or less in the six categories) over the same period and their mean health scores improved by 79%. Following a 12 week augmented home exercise

Assessment of lumbar spinal canal stenosis by magnetic resonance phlebography

International Nuclear Information System (INIS)

Manaka, Masakazu; Komagata, Masashi; Endo, Kenji; Imakiire, Atsuhiro

2003-01-01

There is evidence to suggest that cauda equina intermittent claudication is caused by local circulatory disturbances in the cauda equina as well as compression of the cauda equina. We evaluated the role of magnetic resonance phlebography (MRP) in identifying circulatory disturbances of the vertebral venous system in patients with lumbar spinal canal stenosis. Extensive filling defects of the anterior internal vertebral venous plexus were evident in patients with lumbar spinal canal stenosis (n=53), whereas only milder abnormalities were noted in patients with other lumber diseases (n=16) and none in normal subjects (n=13). The extent of the defect on MRP correlated with the time at which intermittent claudication appeared. In patients with lumber spinal canal stenosis, extensive defects of the internal vertebral venous plexus on MRP were noted in the neutral spine position, but the defect diminished with anterior flexion of the spine. This phenomenon correlated closely with the time at which intermittent claudication appeared. Our results highlight the importance of MRP for assessing the underlying mechanism of cauda equina intermittent claudication in patients with lumbar spinal canal stenosis and suggest that congestive venous ischemia is involved in the development of intermittent claudication in these patients. (author)

Lower-leg symptoms in peripheral arterial disease are associated with anxiety, depression, and anhedonia

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Smolderen, Kim G; Hoeks, Sanne E; Pedersen, Susanne S.

2009-01-01

Patients with peripheral arterial disease (PAD) report diverse clinical manifestations that are not always consistent with classic intermittent claudication. We examined the degree to which atypical exertional leg symptoms, intermittent claudication, and exertional leg symptoms that begin at rest...... 2.5 and 4.0, p...

Hemorrhagic and Ischemic Strokes Compared Stroke Severity, Mortality, and Risk Factors

DEFF Research Database (Denmark)

Andersen, Klaus Kaae; Olsen, T. S.; Dehlendorff, Christian

2009-01-01

were diabetes, atrial fibrillation, previous myocardial infarction, previous stroke, and intermittent arterial claudication. Smoking and alcohol consumption favored HS, whereas age, sex, and hypertension did not herald stroke type. Compared with ischemic strokes, HS was associated with an overall...... higher mortality risk (HR, 1.564; 95% CI, 1.441-1.696). The increased risk was, however, time-dependent; initially, risk was 4-fold, after 1 week it was 2.5-fold, and after 3 weeks it was 1.5-fold. After 3 months stroke type did not correlate to mortality. Conclusion-Strokes are generally more severe...... based on 25 123 individuals with a complete data set. Results-Of the patients 3993 (10.1%) had HS. Stroke severity was almost linearly related to the probability of having HS (2% in patients with the mildest stroke and 30% in those with the most severe strokes). Factors favoring ischemic strokes vs HS...

Increased MCP-1 gene expression in monocytes of severe OSA patients and under intermittent hypoxia.

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Chuang, Li-Pang; Chen, Ning-Hung; Lin, Yuling; Ko, Wen-Shan; Pang, Jong-Hwei S

2016-03-01

Obstructive sleep apnea (OSA) is known to be a risk factor of coronary artery disease. Monocyte chemoattractant protein-1 (MCP-1), as a critical factor for monocyte infiltration, is known to play a role in the development of atherosclerosis. This study aimed to investigate the effect of intermittent hypoxia, the hallmark of OSA, on the MCP-1 expression of monocytes. Peripheral blood was sampled from 61 adults enrolled for suspected OSA. RNA was prepared from the isolated monocytes for the analysis of MCP-1. The effect of in vitro intermittent hypoxia on the regulation and function of MCP-1 was investigated on THP-1 monocytic cells and human monocytes. The mRNA and secreted protein levels were investigated by RT/real-time PCR and enzyme-linked immunosorbent assay, respectively. Monocytic MCP-1 gene expression was found to be increased significantly in severe OSA patients. In vitro intermittent hypoxia was demonstrated to increase the mRNA and protein expression levels of MCP-1 dose- and time-dependently in THP-1 monocytic cells. The MCP-1 mRNA expression in monocytes isolated from OSA patient was induced to a much higher level compared to that from normal control. Pre-treatment with inhibitor for p42/44 MAPK or p38 MAPK suppressed the activation of MCP-1 expression by intermittent hypoxia. This is the first study to demonstrate the increase of MCP-1 gene expression in monocytes of severe OSA patients. In addition, monocytic MCP-1 gene expression can be induced under intermittent hypoxia.

Intermittent Hypoxia Increases the Severity of Bleomycin-Induced Lung Injury in Mice

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Thomas Gille

2018-01-01

Full Text Available Background. Severe obstructive sleep apnea (OSA with chronic intermittent hypoxia (IH is common in idiopathic pulmonary fibrosis (IPF. Here, we evaluated the impact of IH on bleomycin- (BLM- induced pulmonary fibrosis in mice. Methods. C57BL/6J mice received intratracheal BLM or saline and were exposed to IH (40 cycles/hour; FiO2 nadir: 6%; 8 hours/day or intermittent air (IA. In the four experimental groups, we evaluated (i survival; (ii alveolar inflammation, pulmonary edema, lung oxidative stress, and antioxidant enzymes; (iii lung cell apoptosis; and (iv pulmonary fibrosis. Results. Survival at day 21 was lower in the BLM-IH group (p<0.05. Pulmonary fibrosis was more severe at day 21 in BLM-IH mice, as assessed by lung collagen content (p=0.02 and histology. At day 4, BLM-IH mice developed a more severe neutrophilic alveolitis, (p<0.001. Lung oxidative stress was observed, and superoxide dismutase and glutathione peroxidase expression was decreased in BLM-IH mice (p<0.05 versus BLM-IA group. At day 8, pulmonary edema was observed and lung cell apoptosis was increased in the BLM-IH group. Conclusion. These results show that exposure to chronic IH increases mortality, lung inflammation, and lung fibrosis in BLM-treated mice. This study raises the question of the worsening impact of severe OSA in IPF patients.

[Objective evaluation of arterial intermittent claudication by the walking tolerance test. Comparative study of physiological walking and walking on a conveyor belt (author's transl)].

Science.gov (United States)

Bouchet, J Y; Franco, A; Morzol, B; Beani, J C

1980-01-01

Two methods are used to evaluate the walking distance: physiological walking along a standard path (0% - 6 mk/h) and walking on a tread mill (10% - 3 km/h). In both tests, four data are checked: -- initial trouble distance, -- cramp or walking-distance, -- localisation of pain, -- recovery time. These tests are dependable for the diagnosis of arterial claudication, reproducible and well tolerated. Their results have been compared: there is no correlation between the initial trouble distance and the cramp distance. However there is a correlation between the cramp distance by physiological walking and on treadmill. Recovery time, if long, is a criteria of gravity. Interests of both methods are discussed.

Classification of peripheral occlusive arterial diseases based on symptoms, signs and distal blood pressure measurements

DEFF Research Database (Denmark)

Tønnesen, K H; Noer, Ivan; Paaske, William

1980-01-01

Systolic blood pressures at toe and ankle were measured in 459 consecutive patients with occlusive arterial disease. Fifty-eight per cent had intermittent claudication with arterial disease of all degrees of severity. Seventeen per cent complained of rest pain having toe systolic pressures below 30...

Sodium bicarbonate supplementation improves severe-intensity intermittent exercise under moderate acute hypoxic conditions.

Science.gov (United States)

Deb, Sanjoy K; Gough, Lewis A; Sparks, S Andy; McNaughton, Lars R

2018-03-01

Acute moderate hypoxic exposure can substantially impair exercise performance, which occurs with a concurrent exacerbated rise in hydrogen cation (H + ) production. The purpose of this study was therefore, to alleviate this acidic stress through sodium bicarbonate (NaHCO 3 ) supplementation and determine the corresponding effects on severe-intensity intermittent exercise performance. Eleven recreationally active individuals participated in this randomised, double-blind, crossover study performed under acute normobaric hypoxic conditions (FiO 2 % = 14.5%). Pre-experimental trials involved the determination of time to attain peak bicarbonate anion concentrations ([HCO 3 - ]) following NaHCO 3 ingestion. The intermittent exercise tests involved repeated 60-s work in their severe-intensity domain and 30-s recovery at 20 W to exhaustion. Participants ingested either 0.3 g kg bm -1 of NaHCO 3 or a matched placebo of 0.21 g kg bm -1 of sodium chloride prior to exercise. Exercise tolerance (+ 110.9 ± 100.6 s; 95% CI 43.3-178 s; g = 1.0) and work performed in the severe-intensity domain (+ 5.8 ± 6.6 kJ; 95% CI 1.3-9.9 kJ; g = 0.8) were enhanced with NaHCO 3 supplementation. Furthermore, a larger post-exercise blood lactate concentration was reported in the experimental group (+ 4 ± 2.4 mmol l -1 ; 95% CI 2.2-5.9; g = 1.8), while blood [HCO 3 - ] and pH remained elevated in the NaHCO 3 condition throughout experimentation. In conclusion, this study reported a positive effect of NaHCO 3 under acute moderate hypoxic conditions during intermittent exercise and therefore, may offer an ergogenic strategy to mitigate hypoxic induced declines in exercise performance.

Peripheral artery disease (PAD) screening in the asymptomatic population

DEFF Research Database (Denmark)

Sillesen, Henrik; Falk, Erling

2011-01-01

and feet (lower limb), which in the Western world is caused by atherosclerosis if not previous trauma. Whereas severity of intermittent claudication is only poorly related to ABI, cardiovascular outcomes are as follows: the lower the ABI the higher the incidence of cardiovascular events and death...

Increased C-C chemokine receptor 2 gene expression in monocytes of severe obstructive sleep apnea patients and under intermittent hypoxia.

Science.gov (United States)

Chuang, Li-Pang; Chen, Ning-Hung; Lin, Shih-Wei; Chang, Ying-Ling; Liao, Hsiang-Ruei; Lin, Yu-Sheng; Chao, I-Ju; Lin, Yuling; Pang, Jong-Hwei S

2014-01-01

Obstructive sleep apnea (OSA) is known to be a risk factor of coronary artery disease. The chemotaxis and adhesion of monocytes to the endothelium in the early atherosclerosis is important. This study aimed to investigate the effect of intermittent hypoxia, the hallmark of OSA, on the chemotaxis and adhesion of monocytes. Peripheral blood was sampled from 54 adults enrolled for suspected OSA. RNA was prepared from the isolated monocytes for the analysis of C-C chemokine receptor 2 (CCR2). The effect of intermittent hypoxia on the regulation and function of CCR2 was investigated on THP-1 monocytic cells and monocytes. The mRNA and protein expression levels were investigated by RT/real-time PCR and western blot analysis, respectively. Transwell filter migration assay and cell adhesion assay were performed to study the chemotaxis and adhesion of monocytes. Monocytic CCR2 gene expression was found to be increased in severe OSA patients and higher levels were detected after sleep. Intermittent hypoxia increased the CCR2 expression in THP-1 monocytic cells even in the presence of TNF-α and CRP. Intermittent hypoxia also promoted the MCP-1-mediated chemotaxis and adhesion of monocytes to endothelial cells. Furthermore, inhibitor for p42/44 MAPK or p38 MAPK suppressed the activation of monocytic CCR2 expression by intermittent hypoxia. This is the first study to demonstrate the increase of CCR2 gene expression in monocytes of severe OSA patients. Monocytic CCR2 gene expression can be induced under intermittent hypoxia which contributes to the chemotaxis and adhesion of monocytes.

Positiv effekt af intermitterende over- og undertryk (Vacusac) ved claudicatio intermittens

DEFF Research Database (Denmark)

Mehlsen, J; Himmelstrup, H; Himmelstrup, B

1994-01-01

Twenty-two patients with intermittent claudication were included in a double-blinded, randomized trial comparing the effects of 25 treatments with intermittent suction and pressure (Vacusac treatment) to 25 placebo applications given over a period of two months. Twelve patients participated in an...... treatment caused significant increments in ADP-induced platelet aggregation, while the effects on fibrinolysis were uncertain. It is concluded that intermittent suction and pressure treatment offers a new approach for conservative treatment of intermittent claudication....... in an open trial investigating the effects of the same treatment on adenosine diphosphate (ADP)-induced platelet aggregation and fibrinolysis. Active treatment resulted in significant improvements in pain-free and maximal walking distances, whereas no changes could be found during placebo application. Active...

Validation of the Walking Impairment Questionnaire for Spanish patients.

Science.gov (United States)

Lozano, Francisco S; March, José R; González-Porras, José R; Carrasco, Eduardo; Lobos, José M; Areitio-Aurtena, Alix

2013-09-01

The Walking Impairment Questionnaire (WIQ) is a short, easy to complete, disease-specific questionnaire to assess intermittent claudication. A Spanish version of the WIQ for Hispanic Americans has recently been validated in Texas, but it needs to be validated for European Spanish people. After translation and cultural adaptation of the WIQ, 920 patients with intermittent claudication (ankle brachial index Spanish version of the WIQ and European Quality of Life 5 Dimension [EQ-5D]). The validity of the WIQ was determined by correlating WIQ and EQ-5D. Test-retest reliability and internal consistency were determined using the intra-class correlation coefficient (ICC) and Cronbach's alpha, respectively. The three domains of the WIQ were moderately correlated with the EQ-5D health outcome (r = 0.54 to 0.60; p Spanish version of the WIQ for European Spanish patients was valid and reproducible, suggesting that it could be used in Spanish patients with intermittent claudication.

The impact of intermittent or sustained carbon dioxide on intermittent hypoxia initiated respiratory plasticity. What is the effect of these combined stimuli on apnea severity?

Science.gov (United States)

Mateika, Jason H; Panza, Gino; Alex, Raichel; El-Chami, Mohamad

2017-10-31

The following review explores the effect that intermittent or sustained hypercapnia coupled to intermittent hypoxia has on respiratory plasticity. The review explores published work which suggests that intermittent hypercapnia leads to long-term depression of respiration when administered in isolation and prevents the initiation of long-term facilitation when administered in combination with intermittent hypoxia. The review also explores the impact that sustained hypercapnia alone and in combination with intermittent hypoxia has on the magnitude of long-term facilitation. After exploring the outcomes linked to intermittent hypoxia/hypercapnia and intermittent hypoxia/sustained hypercapnia the translational relevance of the outcomes as it relates to breathing stability during sleep is addressed. The likelihood that naturally induced cycles of intermittent hypoxia, coupled to oscillations in carbon dioxide that range between hypocapnia and hypercapnia, do not initiate long-term facilitation is addressed. Moreover, the conditions under which intermittent hypoxia/sustained hypercapnia could serve to improve breathing stability and mitigate co-morbidities associated with sleep apnea are considered. Published by Elsevier B.V.

A Comparison of Clinical Outcomes for Diabetic and Nondiabetic Patients Following Directional Atherectomy in the DEFINITIVE LE Claudicant Cohort.

Science.gov (United States)

Garcia, Lawrence A; Jaff, Michael R; Rocha-Singh, Krishna J; Zeller, Thomas; Bosarge, Christopher; Kamat, Suraj; McKinsey, James F

2015-10-01

To report a subset analysis that evaluated the hypothesis that directional atherectomy for peripheral artery disease in diabetic claudicants has noninferior primary patency at 12 months compared with nondiabetic claudicants. DEFINITIVE LE, a US/European multicenter study, assessed the effectiveness of directional atherectomy using SilverHawk/TurboHawk systems for treatment of peripheral artery disease in the superficial femoral, popliteal, and infrapopliteal arteries. Of the 800 patients enrolled in the study, only the 598 claudicant patients (mean age 69.5±10.4 years; 336 men) who were classified at baseline as Rutherford category 1-3 were eligible for this subset analysis. Of these, 46.8% (280/598) had diabetes. Follow-up to 12 months included duplex ultrasound examination, functional assessments, and adverse event evaluations. Independent angiographic and duplex ultrasound core laboratories assessed primary patency and secondary endpoints; a clinical events committee adjudicated adverse events. Although diabetics had significantly more baseline comorbidities, 12-month primary patency (77.0%) was no different than for nondiabetics (77.9%; superiority p=0.98; noninferiority patherectomy is an effective treatment in diabetic as well as nondiabetic claudicants. Directional atherectomy remains an attractive treatment option, improving luminal diameters without stents, which preserves future treatment options for both diabetic and nondiabetic patients with progressive, diffuse vascular disease. © The Author(s) 2015.

The limits of evidence in drug approval and availability: a case study of cilostazol and naftidrofuryl for the treatment of intermittent claudication.

Science.gov (United States)

Hong, Haeyeon; Mackey, William C

2014-08-01

Despite numerous efforts to develop effective medications for the treatment of intermittent claudication (IC) over the past 4 decades, a gold standard medical management option has yet to be defined. Although not life-threatening, IC interferes with mobility and activities of daily living, significantly impairing quality of life and potentially causing depression. Cilostazol, the leading pharmacologic agent for IC in the United States, was approved by the US Food and Drug Administration (FDA) in 1999 based on controversial data. Meanwhile, naftidrofuryl, the first-line pharmacologic agent for IC in the United Kingdom and Europe, has never been approved by the FDA and therefore is not available in the United States. The clinical data for cilostazol and naftidrofuryl are plagued by flaws related to lack of protocol standardization, objective endpoints, and strict eligibility criteria in study subjects, making identification of a true treatment effect impossible. Furthermore, no prospective randomized trial comparing the efficacy of cilostazol and naftidrofuryl has been conducted, because the manufacturers of these agents have much to lose and little to gain from such a study. This article provides an overview of the pharmacology of cilostazol and naftidrofuryl, and the clinical studies leading to their approval and clinical acceptance. It further explores the possible sources of bias in analyzing these clinical trials, some of which have been brought to light by the National Institute for Health and Clinical Excellence (NICE) of the United Kingdom in its technology appraisal guidance. It also speculates the ways in which economic incentives may affect drug-marketing decisions. A literature review of pharmacology and clinical trials for cilostazol and naftidrofuryl was performed in PubMed. The majority of included clinical trials were initially identified through the most recent Cochrane review articles as well as the FDA's approval packet for cilostazol. The

Comparative analysis of different modalities of assessment of lower ...

African Journals Online (AJOL)

LEAD was assessed in all the patients using: 1. History of intermittent claudication using the Edinburgh Claudication Questionnaire. 2. Palpation of pedal pulses for diminished or absent dorsalis pedis and/or posterior tibial artery pulsations. 3. Ankle Brachial Index <0.9 in either leg, using hand-held Doppler ultrasonography

Patient Characteristics and Comorbidities Influence Walking Distances in Symptomatic Peripheral Arterial Disease: A Large One-Year Physiotherapy Cohort Study.

Science.gov (United States)

Dörenkamp, Sarah; Mesters, Ilse; de Bie, Rob; Teijink, Joep; van Breukelen, Gerard

2016-01-01

The aim of this study is to investigate the association between age, gender, body-mass index, smoking behavior, orthopedic comorbidity, neurologic comorbidity, cardiac comorbidity, vascular comorbidity, pulmonic comorbidity, internal comorbidity and Initial Claudication Distance during and after Supervised Exercise Therapy at 1, 3, 6 and 12 months in a large sample of patients with Intermittent Claudication. Data was prospectively collected in standard physiotherapy care. Patients received Supervised Exercise Therapy according to the guideline Intermittent Claudication of the Royal Dutch Society for Physiotherapy. Three-level mixed linear regression analysis was carried out to analyze the association between patient characteristics, comorbidities and Initial Claudication Distance at 1, 3, 6 and 12 months. Data from 2995 patients was analyzed. Results showed that being female, advanced age and a high body-mass index were associated with lower Initial Claudication Distance at all-time points (p = 0.000). Besides, a negative association between cardiac comorbidity and Initial Claudication Distance was revealed (p = 0.011). The interaction time by age, time by body-mass index and time by vascular comorbidity were significantly associated with Initial Claudication Distance (p≤ 0.05). Per year increase in age (range: 33-93 years), the reduction in Initial Claudication Distance was 8m after 12 months of Supervised Exercise Therapy. One unit increase in body-mass index (range: 16-44 kg/m2) led to 10 m less improvement in Initial Claudication Distance after 12 months and for vascular comorbidity the reduction in improvement was 85 m after 12 months. This study reveals that females, patients at advanced age, patients with a high body-mass index and cardiac comorbidity are more likely to show less improvement in Initial Claudication Distances (ICD) after 1, 3, 6 and 12 months of Supervised Exercise Therapy. Further research should elucidate treatment adaptations that

Impact of a single session of intermittent pneumatic leg compressions on skeletal muscle and isolated artery gene expression in rats.

Science.gov (United States)

Roseguini, Bruno T; Arce-Esquivel, Arturo A; Newcomer, Sean C; Laughlin, M H

2011-12-01

Intermittent pneumatic leg compressions (IPC) have proven to be an effective noninvasive approach for treatment of patients with claudication, but the mechanisms underlying the clinical benefits remain elusive. In the present study, a rodent model of claudication produced by bilateral ligation of the femoral artery was used to investigate the acute impact of a single session of IPC (150 min) on hemodynamics, skeletal muscle (tibialis anterior), and isolated collateral artery (perforating artery) expression of a subset of genes associated with inflammation and vascular remodeling. In addition, the effect of compression frequency (15 vs. 3 compressions/min) on the expression of these factors was studied. In ligated animals, IPC evoked an increase of monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant 1 (CXCL1) mRNA (P < 0.01) and immunostaining (P < 0.05), as well as a minor increase in VEGF immunostaining in the muscle endomysium 150 min postintervention. Further, collateral arteries from these animals showed an increased expression of MCP-1 (approximately twofold, P = 0.02). These effects were most evident in the group exposed to the high-frequency protocol (15 compressions/min). In contrast, IPC in sham-operated control animals evoked a modest initial upregulation of VEGF (P = 0.01), MCP-1 (P = 0.02), and CXCL1 (P = 0.03) mRNA in the muscle without concomitant changes in protein levels. No changes in gene expression were observed in arteries isolated from sham animals. In conclusion, IPC acutely up-regulates the expression of important factors involved in vascular remodeling in the compressed muscle and collateral arteries in a model of hindlimb ischemia. These effects appear to be dependent on the compression frequency, such that a high compression frequency (15 compressions/min) evokes more consistent and robust effects compared with the frequency commonly employed clinically to treat patients with claudication (3

Effects of vacusac in intermittent claudication

DEFF Research Database (Denmark)

Himmelstrup, H; Himmelstrup, Bodil; Mehlsen, J

1991-01-01

. Seventeen patients completed the study. The effect of treatment was quantified by measurements of systemic and peripheral systolic blood pressures and by measurements of the pain-free and the maximal walking distance on a treadmill. The ankle pressure index (ankle systolic pressure/arm systolic pressure...

Metabolic Effects of Intermittent Fasting.

Science.gov (United States)

Patterson, Ruth E; Sears, Dorothy D

2017-08-21

The objective of this review is to provide an overview of intermittent fasting regimens, summarize the evidence on the health benefits of intermittent fasting, and discuss physiological mechanisms by which intermittent fasting might lead to improved health outcomes. A MEDLINE search was performed using PubMed and the terms "intermittent fasting," "fasting," "time-restricted feeding," and "food timing." Modified fasting regimens appear to promote weight loss and may improve metabolic health. Several lines of evidence also support the hypothesis that eating patterns that reduce or eliminate nighttime eating and prolong nightly fasting intervals may result in sustained improvements in human health. Intermittent fasting regimens are hypothesized to influence metabolic regulation via effects on (a) circadian biology, (b) the gut microbiome, and (c) modifiable lifestyle behaviors, such as sleep. If proven to be efficacious, these eating regimens offer promising nonpharmacological approaches to improving health at the population level, with multiple public health benefits.

MILD® Is an Effective Treatment for Lumbar Spinal Stenosis with Neurogenic Claudication: MiDAS ENCORE Randomized Controlled Trial.

Science.gov (United States)

Benyamin, Ramsin M; Staats, Peter S; MiDAS Encore, Investigators

2016-05-01

, NPRS, and all 3 ZCQ domains (Symptom Severity, Physical Function and Patient Satisfaction) demonstrated statistically significant superiority of MILD versus the active control. For primary efficacy, the 58.0% ODI responder rate in the MILD group was higher than the 27.1% responder rate in the epidural steroid group (P < 0.001). The primary safety endpoint was achieved, demonstrating that there is no difference in safety between MILD and ESIs (P = 1.00). There was a lack of patient blinding due to considerable differences in treatment protocols, and a potentially higher non-responder rate for both groups versus standard-of-care due to adjunctive pain therapy study restrictions. Study enrollment was not limited to patients that had never received ESI therapy. One-year results of this randomized controlled clinical trial demonstrate that MILD is statistically superior to ESIs in the treatment of LSS patients with neurogenic claudication and verified central stenosis due to ligamentum flavum hypertrophy. Primary and secondary efficacy outcome measures achieved statistical superiority in the MILD group compared to the control group. With 95% of patients in this study presenting with 5 or more LSS co-factors, it is important to note that patients with spinal co-morbidities also experienced statistically significant improved function that was durable through 1 year. MILD, minimally invasive lumbar decompression, interlaminar epidural steroid injections, ESI neurogenic claudication, ligamentum flavum, ENCORE, PILD, CED Study, LSS.

Doppler ultrasound exam of an arm or leg

Science.gov (United States)

Peripheral vascular disease - Doppler; PVD - Doppler; PAD - Doppler; Blockage of leg arteries - Doppler; Intermittent claudication - Doppler; Arterial insufficiency of the legs - Doppler; Leg pain and ...

Stent-induced flow disturbances in the ipsilateral external carotid artery following internal carotid artery stenting: a temporary cause of jaw claudication.

Science.gov (United States)

Giurgea, Georgiana-Aura; Haumer, Markus; Mlekusch, Irene; Sabeti-Sandor, Schila; Dick, Petra; Schillinger, Martin; Minar, Erich; Mlekusch, Wolfgang

2017-07-01

We hypothesize that stenting of the internal carotid artery can immediately impede blood flow to the external carotid artery by either plaque shift or stent coverage of the ostium, and thereby cause ischemic symptoms like ipsilateral jaw claudication. Thirty-three patients with high-grade asymptomatic stenosis of the internal carotid artery who underwent endovascular treatment were examined by ultrasound of the external carotid artery and performed an exercise test by chewing chewing gum synchronously to an electronic metronome for 3 min. Tests were performed before, the day after, and 1 week after the stenting procedure. Claudication time was defined as the timespan until occurrence of pain of the masseter muscle and/or chewing dyssynchrony to the metronome for more than 15 s. Ten patients with an isolated, atherosclerotic stenosis of the external carotid artery served as controls. A significantly reduced claudication time (in seconds) was recorded in patients who underwent carotid artery stenting compared to baseline values; median 89 (interquartile range, IQR, 57 to 124) vs. median 180 (IQR 153 to 180; p external carotid artery into faster or slower as 200 cm/sec, the effect was even accentuated. Stenting values showed improvement 1 week after but did not return to baseline levels. No respective changes were found in controls. Stenting of the internal carotid artery lead to ipsilateral flow deterioration at the external carotid artery resulting in temporary jaw claudication. This impairment attenuated over the time and was significantly reduced after 1 week.

[Lumbar spondylosis].

Science.gov (United States)

Seichi, Atsushi

2014-10-01

Lumbar spondylosis is a chronic, noninflammatory disease caused by degeneration of lumbar disc and/or facet joints. The etiology of lumbar spondylosis is multifactorial. Patients with lumbar spondylosis complain of a broad variety of symptoms including discomfort in the low back lesion, whereas some of them have radiating leg pain or neurologenic intermittent claudication (lumbar spinal stenosis). The majority of patients with spondylosis and stenosis of the lumbosacral spine can be treated nonsurgically. Nonsteroidal anti-inflammatory drugs and COX-2 inhibitors are helpful in controlling symptoms. Prostaglandin, epidural injection, and transforaminal injection are also helpful for leg pain and intermittent claudication. Operative therapy for spinal stenosis or spondylolisthesis is reserved for patients who are totally incapacitated by their condition.

Hemorrhagic and ischemic strokes compared: stroke severity, mortality, and risk factors.

Science.gov (United States)

Andersen, Klaus Kaae; Olsen, Tom Skyhøj; Dehlendorff, Christian; Kammersgaard, Lars Peter

2009-06-01

Stroke patients with hemorrhagic (HS) and ischemic strokes were compared with regard to stroke severity, mortality, and cardiovascular risk factors. A registry started in 2001, with the aim of registering all hospitalized stroke patients in Denmark, now holds information for 39,484 patients. The patients underwent an evaluation including stroke severity (Scandinavian Stroke Scale), CT, and cardiovascular risk factors. They were followed-up from admission until death or censoring in 2007. Independent predictors of death were identified by means of a survival model based on 25,123 individuals with a complete data set. Of the patients 3993 (10.1%) had HS. Stroke severity was almost linearly related to the probability of having HS (2% in patients with the mildest stroke and 30% in those with the most severe strokes). Factors favoring ischemic strokes vs HS were diabetes, atrial fibrillation, previous myocardial infarction, previous stroke, and intermittent arterial claudication. Smoking and alcohol consumption favored HS, whereas age, sex, and hypertension did not herald stroke type. Compared with ischemic strokes, HS was associated with an overall higher mortality risk (HR, 1.564; 95% CI, 1.441-1.696). The increased risk was, however, time-dependent; initially, risk was 4-fold, after 1 week it was 2.5-fold, and after 3 weeks it was 1.5-fold. After 3 months stroke type did not correlate to mortality. Strokes are generally more severe in patients with HS. Within the first 3 months after stroke, HS is associated with a considerable increase of mortality, which is specifically associated with the hemorrhagic nature of the lesion.

Below knee angioplasty in elderly patients: Predictors of major adverse clinical outcomes.

LENUS (Irish Health Repository)

Keeling, Aoife N

2011-03-01

To determine predictors of clinical outcome following percutaneous transluminal angioplasty (PTA) in elderly patients with below knee atherosclerotic lesions causing intermittent claudication (IC) or critical limb ischaemia (CLI).

Estudo comparativo da evolução e sobrevida de pacientes com claudicação intermitente, com ou sem limitação para exercícios, acompanhados em ambulatório específico Comparative study of evolution and survival of patients with intermittent claudication, with or without limitation for exercises, followed in a specific outpatient setting

Directory of Open Access Journals (Sweden)

Ricardo de Alvarenga Yoshida

2008-06-01

established, as well as the benefits of physical training in the treatment of intermittent claudication (IC. However, current data do not provide enough information about the relationship between clinical limitations and risk factors and the performance of physical training and its implications on the evolution and mortality of these patients. OBJECTIVE: To compare the claudication distance and survival of patients with IC throughout time in a specific outpatient setting, with or without limitation for exercises. METHODS: A retrospective cohort study was performed to review the protocols of 185 patients and 469 returns, from 1999 to 2005, evaluating demographic data, average claudication distance and death. The data were analyzed using the software Epi-Info, version 3.2, and SAS, version 8.2. RESULTS: Mean age was 60.9±11.1 years; 61.1% were males and 38.9% were females; 87% were Caucasians and 13% were non-Caucasians. Associated risk factors were hypertension (69.7%, smoking (44.3%, dyslipidemia (32.4%, and diabetes (28.6%. For the patients with claudicating distance lower than 500 m, mean initial distance was 154.0±107.6 m and final distance was 199.8±120.5 m. About 45% of the patients had some clinical limitation to perform the prescribed exercise program, such as angina (26.0%, stroke (4.3%, osteoarthrosis (3.8%, previous minor or major amputation (2.1%, or chronic obstructive pulmonary disease (1.6%. About 11.4% of the patients had previous myocardial infarction, and 5.4% of them were using cardiotonic drugs. Mean follow-up time was 16.0±14.4 months. Mean claudication distance increased 100% (418.47 to 817.74 m throughout 2 years in the group without limitation (p < 0.001 and in nonsmokers (p < 0.001. Survival rate of patients with IC was significantly reduced in the group with limitation for exercises. Logistic regression analysis showed that limitation to exercises was the single factor significantly influencing mortality (p < 0.001. CONCLUSION: Proper and regular

Intermittent, noncyclic dysfunction of a mechanical aortic prosthesis by pannus formation.

Science.gov (United States)

Giroux, Sylvie K; Labinaz, Marino X; Grisoli, Dominique; Klug, Andrew P; Veinot, John P; Burwash, Ian G

2010-01-01

Mechanical aortic prosthesis dysfunction can result from thrombosis or pannus formation. Pannus formation usually restricts systolic excursion of the occluding disk, resulting in progressive stenosis of the aortic prosthesis. Intermittent dysfunction of a mechanical aortic prosthesis is usually ascribed to thrombus formation. We describe an unusual case of intermittent, noncyclic dysfunction of a mechanical aortic prosthesis due to pannus formation in the absence of systolic restriction of disk excursion that presented with intermittent massive aortic regurgitation, severe ischemia, and shock. Pannus formation should be considered as a potential cause of acute intermittent severe aortic regurgitation in a patient with a mechanical aortic prosthesis.

Energy intermittency

CERN Document Server

Sorensen, Bent

2014-01-01

The first book to consider intermittency as a key point of an energy system, Energy Intermittency describes different levels of variability for traditional and renewable energy sources, presenting detailed solutions for handling energy intermittency through trade, collaboration, demand management, and active energy storage. Addressing energy supply intermittency systematically, this practical text:Analyzes typical time-distributions and intervals between episodes of demand-supply mismatch and explores their dependence on system layouts and energy source characteristicsSimulates scenarios regar

Intermittent Hypoxia Causes Inflammation and Injury to Human Adult Cardiac Myocytes.

Science.gov (United States)

Wu, Jing; Stefaniak, Joanna; Hafner, Christina; Schramel, Johannes Peter; Kaun, Christoph; Wojta, Johann; Ullrich, Roman; Tretter, Verena Eva; Markstaller, Klaus; Klein, Klaus Ulrich

2016-02-01

Intermittent hypoxia may occur in a number of clinical scenarios, including interruption of myocardial blood flow or breathing disorders such as obstructive sleep apnea. Although intermittent hypoxia has been linked to cardiovascular and cerebrovascular disease, the effect of intermittent hypoxia on the human heart is not fully understood. Therefore, in the present study, we compared the cellular responses of cultured human adult cardiac myocytes (HACMs) exposed to intermittent hypoxia and different conditions of continuous hypoxia and normoxia. HACMs were exposed to intermittent hypoxia (0%-21% O2), constant mild hypoxia (10% O2), constant severe hypoxia (0% O2), or constant normoxia (21% O2), using a novel cell culture bioreactor with gas-permeable membranes. Cell proliferation, lactate dehydrogenase release, vascular endothelial growth factor release, and cytokine (interleukin [IL] and macrophage migration inhibitory factor) release were assessed at baseline and after 8, 24, and 72 hours of exposure. A signal transduction pathway finder array was performed to determine the changes in gene expression. In comparison with constant normoxia and constant mild hypoxia, intermittent hypoxia induced earlier and greater inflammatory response and extent of cell injury as evidenced by lower cell numbers and higher lactate dehydrogenase, vascular endothelial growth factor, and proinflammatory cytokine (IL-1β, IL-6, IL-8, and macrophage migration inhibitory factor) release. Constant severe hypoxia showed more detrimental effects on HACMs at later time points. Pathway analysis demonstrated that intermittent hypoxia primarily altered gene expression in oxidative stress, Wnt, Notch, and hypoxia pathways. Intermittent and constant severe hypoxia, but not constant mild hypoxia or normoxia, induced inflammation and cell injury in HACMs. Cell injury occurred earliest and was greatest after intermittent hypoxia exposure. Our in vitro findings suggest that intermittent hypoxia

Estimated Probability of Stroke Among Medical Outpatients in Enugu ...

African Journals Online (AJOL)

diabetes were recruited irrespective of their last fasting plasma glucose levels. ... myocardial infarction or intermittent claudication, angina pectoris, coronary .... obesity are generally higher in older women hence increasing their risk of ...

Stroke in Malawi – What do we know about it and How should we ...

African Journals Online (AJOL)

2010-03-28

Mar 28, 2010 ... ○There are no data on the impact of hyperlipidaemia, obesity or genetic factors on .... Atheroma markers (angina, diabetes, intermittent claudication) ... Investigations. ○ Fasting blood glucose (and random on admission),.

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.

Ketanserin effect on limb perfusion and arterial collaterals

International Nuclear Information System (INIS)

Grassi, C.J.; Janicek, M.; Hollenberg, N.K.; Meyerovitz, M.F.; Harrington, D.P.

1987-01-01

Arterial collateral flow and major vessel patency are important in patients with intermittent claudication. Activity of serotonin released from platelets has been demonstrated experimentally, and serotonin antagonists have been investigated in treadmill testing. Ketanserin, a serotonin (5-HT/sup 2/) antagonist, was investigated in 20 patients with intermittent claudication to assess its effect on collaterals. Blood-pressure ratio (thigh/arm), mercury-strain gauge plethysmography, Doppler pressures, and repeat arteriography were performed. Ketanserin (3-30 μg/kg IA) increased collateral vessel size on angiography in 12 patients (60%) and increased blood-flow ratio and plethysmogrpahy pressures on average. These observations, confirming clinical studies that some patients show a dramatic response and others do not, might prove useful in identifying patients who will respond to ketanserin for occlusive vascular disease

Interspinous process device versus standard conventional surgical decompression for lumbar spinal stenosis: Randomized controlled trial

NARCIS (Netherlands)

W.A. Moojen (Wouter); M.P. Arts (Mark); W.C.H. Jacobs (Wilco); E.W. van Zwet (Erik); M.E. van den Akker-van Marle (Elske); B.W. Koes (Bart); C.L.A.M. Vleggeert-Lankamp (Carmen); W.C. Peul (Wilco)

2013-01-01

markdownabstractAbstract Objective To assess whether interspinous process device implantation is more effective in the short term than conventional surgical decompression for patients with intermittent neurogenic claudication due to lumbar spinal stenosis. Design Randomized controlled

Deletion of MAOA and MAOB in a male patient causes severe developmental delay, intermittent hypotonia and stereotypical hand movements

OpenAIRE

Whibley, Annabel; Urquhart, Jill; Dore, Jonathan; Willatt, Lionel; Parkin, Georgina; Gaunt, Lorraine; Black, Graeme; Donnai, Dian; Raymond, F Lucy

2010-01-01

Monoamine oxidases (MAO-A and MAO-B) have a key role in the degradation of amine neurotransmitters, such as dopamine, norepinephrine and serotonin. We identified an inherited 240 kb deletion on Xp11.3–p11.4, which encompasses both monoamine oxidase genes but, unlike other published reports, does not affect the adjacent Norrie disease gene (NDP). The brothers who inherited the deletion, and thus have no monoamine oxidase function, presented with severe developmental delay, intermittent hypoton...

Intermittent search strategies

Science.gov (United States)

Bénichou, O.; Loverdo, C.; Moreau, M.; Voituriez, R.

2011-01-01

This review examines intermittent target search strategies, which combine phases of slow motion, allowing the searcher to detect the target, and phases of fast motion during which targets cannot be detected. It is first shown that intermittent search strategies are actually widely observed at various scales. At the macroscopic scale, this is, for example, the case of animals looking for food; at the microscopic scale, intermittent transport patterns are involved in a reaction pathway of DNA-binding proteins as well as in intracellular transport. Second, generic stochastic models are introduced, which show that intermittent strategies are efficient strategies that enable the minimization of search time. This suggests that the intrinsic efficiency of intermittent search strategies could justify their frequent observation in nature. Last, beyond these modeling aspects, it is proposed that intermittent strategies could also be used in a broader context to design and accelerate search processes.

Symptomatic peripheral arterial disease: the value of a validated questionnaire and a clinical decision rule

NARCIS (Netherlands)

Bendermacher, Bianca L. W.; Teijink, Joep A. W.; Willigendael, Edith M.; Bartelink, Marie-Louise; Büller, Harry R.; Peters, Ron J. G.; Boiten, Jelis; Langenberg, Machteld; Prins, Martin H.

2006-01-01

BACKGROUND: If a validated questionnaire, when applied to patients reporting with symptoms of intermittent claudication, could adequately discriminate between those with and without peripheral arterial disease, GPs could avoid the diagnostic measurement of the ankle brachial index. AIM: To

peripheralarterial disease in rheumatoid arthritis patients at the ...

African Journals Online (AJOL)

2011-12-12

Dec 12, 2011 ... five (27.7%) of the study subjects exhibited symptoms of intermittent claudication,. 13(52%) of them had ... musculoskeletal impairment may not favour exercise induced ... Or a fasting blood glucose of >7mmol or random blood ...

Factors Relevant to Utility Integration of Intermittent Renewable Technologies

Energy Technology Data Exchange (ETDEWEB)

Wan, Y.; Parsons, B.

1993-08-24

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 fmdings 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 am feasible); and (3) intermittent renewable energy technologies can have capacity values. Obstacles still interfering with intermittent renewable technologies are also indentified.

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.

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.

Mass or high-risk screening for abdominal aortic aneurysm

DEFF Research Database (Denmark)

Lindholt, Jes Sanddal; Henneberg, E W; Fasting, H

1997-01-01

Abdominal aortic aneurysm (AAA) is known to be associated with various diseases, especially hypertension, acute myocardial infarction (AMI), chronic obstructive airway disease (COAD), and intermittent claudication. These associations have led to a debate about whether screening of older men for AAA...

White adipose tissue coloring by intermittent fasting.

Science.gov (United States)

Kivelä, Riikka; Alitalo, Kari

2017-11-01

Intermittent fasting (IF) has been shown to promote metabolic health in several organisms. Two recent papers show that IF induces white adipose tissue beiging and increases thermogenesis, which improves metabolic health in mice.

Sliding Intermittent Control for BAM Neural Networks with Delays

Directory of Open Access Journals (Sweden)

Jianqiang Hu

2013-01-01

Full Text Available This paper addresses the exponential stability problem for a class of delayed bidirectional associative memory (BAM neural networks with delays. A sliding intermittent controller which takes the advantages of the periodically intermittent control idea and the impulsive control scheme is proposed and employed to the delayed BAM system. With the adjustable parameter taking different particular values, such a sliding intermittent control method can comprise several kinds of control schemes as special cases, such as the continuous feedback control, the impulsive control, the periodically intermittent control, and the semi-impulsive control. By using analysis techniques and the Lyapunov function methods, some sufficient criteria are derived for the closed-loop delayed BAM neural networks to be globally exponentially stable. Finally, two illustrative examples are given to show the effectiveness of the proposed control scheme and the obtained theoretical results.

Effects of vacuum compression therapy on skin microcirculation in patients suffering from lower limb ischaemia

NARCIS (Netherlands)

Ubbink, D. T.; van der Oord, B. M.; Sobotka, M. R.; Jacobs, M. J.

2000-01-01

We investigated the short-term effect of vacuum compression (VC) treatment on skin microcirculatory perfusion in the foot of patients with lower limb ischaemia and healthy controls. Ten patients with intermittent claudication or rest pain and 5 healthy controls underwent vacuum-compression treatment

Vitamin E and cardiovascular disease

NARCIS (Netherlands)

Kleijnen, J.; Knipschild, P.; ter Riet, G.

1989-01-01

Randomized clinical trials of the effects of Vitamin E on complaints of intermittent claudication and angina pectoris are reviewed, and their methodological shortcomings are considered. Mechanisms by which Vitamin E might act in cardiovascular disease are discussed. The evidence about the possible

The prevalence and association of low testosterone levels in a ...

African Journals Online (AJOL)

Men with obesity, metabolic syndrome and type 2 diabetes often have low total and free .... used to diagnose intermittent claudication.22 It consists of nine questions, and ... in the fasting state between 7h:00 am and 10:00 am in clotting.

Padma-28, et urtepraeparat, øger gangdistancen hos patienter med claudicatio intermittens

DEFF Research Database (Denmark)

Drabaek, H; Mehlsen, J; Petersen, J R

1994-01-01

Thirty-six patients with stable intermittent claudication were randomized in a doubleblind study either to treatment with two tablets of Padma-28 twice daily (containing 340 mg dried herbal mixture composed according to an ancient lamaistic prescription) or placebo for four months. Effect...

Mobility and cloud: operating in intermittent, austere network conditions

OpenAIRE

Wee, Toon Joo; Ling, Yu Xian Eldine

2014-01-01

Approved for public release; distribution is unlimited Cloud computing is emerging as the mainstream platform for a range of on-demand applications, services, and infrastructure. Before the benefits of cloud computing are realized, several technology challenges must be addressed. Operating in intermittent and austere network conditions is one of such challenges, which navy ships face when communicating with land-based cloud computing environments. Given limited bandwidth and intermittent c...

Intermittent degradation and schizotypy

Directory of Open Access Journals (Sweden)

Matthew W. Roché

2015-06-01

Full Text Available 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-report questionnaires assessing schizotypy and psychological state variables (e.g., anxiety, depression, and their reaction times were recorded as they did so. Intermittent degradation was defined as the number of times a subject’s reaction time for questionnaire items met or exceeded three standard deviations from his or her mean reaction time after controlling for each item’s information processing load. Intermittent degradation scores were correlated with questionnaire scores. Our results indicate that intermittent degradation is associated with total scores on measures of positive and disorganized schizotypy, but unrelated to total scores on measures of negative schizotypy and psychological state variables. Intermittent degradation is interpreted as potentially derivative of schizotypy and a candidate endophenotypic marker worthy of continued research.

Reproducibility of proximal and distal transcutaneous oxygen pressure measurements during exercise in stage 2 arterial claudication.

Science.gov (United States)

Bouyé, P; Picquet, J; Jaquinandi, V; Enon, B; Leftheriotis, G; Saumet, J-L; Abraham, P

2004-06-01

Although transcutaneous oxygen pressure measurements (tcpO2) are largely used in the investigation of vascular patients, its reproducibility is still debated. Indeed an unpredictable gradient exists between arterial and transcutaneous oxygen pressure. We hypothesised that indices taking into account changes over time and independent of absolute starting values would be more reproducible than other indices. comparative test-retest procedure (1 to 13 days between tests). institutional practice, ambulatory care. 15 subjects with stage 2 claudication. tcpO2 recordings at rest and at exercise during the 2 treadmill tests. calculation of the Delta-from-rest of oxygen pressure index (limb tcpO2 changes minus chest tcpO2 changes), of the resting - or minimal values attained during exercise - of absolute tcpO2 and of the regional perfusion index (regional perfusion index: ration of limb to chest). Both absolute tcpO2 and regional perfusion index at rest showed low reproducibility. During exercise the best reproducibility was attained through Delta-from-rest of oxygen pressure index calculation. Equations from the linear regression analysis (test 2 versus test 1) were 0.88 x -4.2 (r(2)=0.82) at the buttock level and 0.82 x -3.8 (r(2)=0.80) at the calf level. TcpO2 measurement on the calf or buttock during exercise, is a reproducible measurement in patients with vascular claudication, specifically when corrected for exercise-induced systemic pO2 changes trough Delta-from-rest of oxygen pressure calculation.

Severe acute intermittent hypoxia elicits phrenic long-term facilitation by a novel adenosine-dependent mechanism

Science.gov (United States)

Nichols, Nicole L.; Dale, Erica A.

2012-01-01

Acute intermittent hypoxia [AIH; 3, 5-min episodes; 35–45 mmHg arterial Po2 (PaO2)] elicits serotonin-dependent phrenic long-term facilitation (pLTF), a form of phrenic motor facilitation (pMF) initiated by Gq protein-coupled metabotropic 5-HT2 receptors. An alternate pathway to pMF is induced by Gs protein-coupled metabotropic receptors, including adenosine A2A receptors. AIH-induced pLTF is dominated by the serotonin-dependent pathway and is actually restrained via inhibition from the adenosine-dependent pathway. Here, we hypothesized that severe AIH shifts pLTF from a serotonin-dependent to an adenosine-dependent form of pMF. pLTF induced by severe (25–30 mmHg PaO2) and moderate (45–55 mmHg PaO2) AIH were compared in anesthetized rats, with and without intrathecal (C4) spinal A2A (MSX-3, 130 ng/kg, 12 μl) or 5-HT receptor antagonist (methysergide, 300 μg/kg, 15 μl) injections. During severe, but not moderate AIH, progressive augmentation of the phrenic response during hypoxic episodes was observed. Severe AIH (78% ± 8% 90 min post-AIH, n = 6) elicited greater pLTF vs. moderate AIH (41% ± 12%, n = 8; P MSX-3 (28% ± 6%; n = 6; P 0.05). Thus severe AIH shifts pLTF from a serotonin-dependent to an adenosine-dependent mechanism; the adenosinergic pathway inhibits the serotonergic pathway following moderate AIH. Here we demonstrate a novel adenosine-dependent pathway to pLTF following severe AIH. Shifts in the mechanisms of respiratory plasticity provide the ventilatory control system greater flexibility as challenges that differ in severity are confronted. PMID:22403346

Development of quality indicators for physiotherapy for patients with PAOD in the Netherlands: a Delphi study

NARCIS (Netherlands)

Gijsbers, H. J. H.; Lauret, G. J.; van Hofwegen, A.; van Dockum, T. A.; Teijink, J. A. W.; Hendriks, H. J. M.

2016-01-01

The aim of the study was to develop quality indicators (QIs) for physiotherapy management of patients with intermittent claudication (IC) in the Netherlands. As part of an international six-step method to develop QIs, an online survey Delphi-procedure was completed. After two Delphi-rounds a

Quality of provided care in vascular surgery : outcome assessment & improvement strategies

NARCIS (Netherlands)

Flu, Hans Christiaan

2010-01-01

The aim of this thesis was to evaluate the quality of care in vascular surgery in end-stage renal disease (ESRD) and peripheral arterial occlusive disease (PAOD): intermittent claudication (IC) and critical lower limb ischaemia (CLI) patients. Therefore firstly it focused on the improvement of the

Subintimal angioplasty: predictors of long-term success.

LENUS (Irish Health Repository)

Keeling, Aoife N

2009-08-01

To determine the clinical outcomes and success rates after percutaneous subintimal angioplasty (SIA) in patients with lower-limb occlusive lesions causing intermittent claudication (IC) or critical limb ischemia (CLI) at midterm to long-term follow-up. The secondary aim was to elicit factors predictive of a successful outcome.

Intermittency in Hall-magnetohydrodynamics with a strong guide field

International Nuclear Information System (INIS)

Rodriguez Imazio, P.; Martin, L. N.; Dmitruk, P.; Mininni, P. D.

2013-01-01

We present a detailed study of intermittency in the velocity and magnetic field fluctuations of compressible Hall-magnetohydrodynamic turbulence with an external guide field. To solve the equations numerically, a reduced model valid when a strong guide field is present is used. Different values for the ion skin depth are considered in the simulations. The resulting data are analyzed computing field increments in several directions perpendicular to the guide field, and building structure functions and probability density functions. In the magnetohydrodynamic limit, we recover the usual results with the magnetic field being more intermittent than the velocity field. In the presence of the Hall effect, field fluctuations at scales smaller than the ion skin depth show a substantial decrease in the level of intermittency, with close to monofractal scaling

Complementary therapies for peripheral arterial disease: systematic review.

Science.gov (United States)

Pittler, Max H; Ernst, Edzard

2005-07-01

While peripheral arterial disease (PAD) affects a considerable proportion of patients in the primary care setting, there is a high level of use of complementary treatment options. The aim was to assess the effectiveness of any type of complementary therapy for peripheral arterial disease. A systematic review was performed. Literature searches were conducted on Medline, Embase, Amed, and the Cochrane Library until December 2004. Hand-searches of medical journals and bibliographies were conducted. There were no restrictions regarding the language of publication. The screening of studies, selection, data extraction, the assessment of methodologic quality and validation were performed independently by the two reviewers. Data from randomized controlled trials, and systematic reviews and meta-analyses, which based their findings on the results of randomized controlled trials were included. Seven systematic reviews and meta-analyses and three additional randomized controlled trials met the inclusion criteria and were reviewed. The evidence relates to acupuncture, biofeedback, chelation therapy, CO(2)-applications and the dietary supplements Allium sativum (garlic), Ginkgo biloba (ginkgo), omega-3 fatty acids, padma 28 and Vitamin E. Most studies included only patients with peripheral arterial disease in Fontaine stage II (intermittent claudication). The reviewed RCTs, systematic reviews and meta-analyses which based their findings on the results of RCTs suggest that G. biloba is effective compared with placebo for patients with intermittent claudication. Evidence also suggests that padma 28 is effective for intermittent claudication, although more data are required to confirm these findings. For all other complementary treatment options there is no evidence beyond reasonable doubt to suggest effectiveness for patients with peripheral arterial disease.

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.

Dacron or PTFE for Above-knee Femoropopliteal Bypass. A Multicenter Randomised Study

DEFF Research Database (Denmark)

Jensen, L. P.; Lepäntalo, M.; Fossdal, J. E.

2007-01-01

more often than patients operated on for intermittent claudication, 10 and 3 respectively (p=0.003), and had higher mortality rates, 20% and 8% respectively (p=0.001). CONCLUSION: This trial confirms that Dacron is at least as durable as PTFE for above-knee bypass procedures, and might even be superior....

ISSN 2073 ISSN 2073-9990 East Cent. East Cent. East Cent. Afr. J.

African Journals Online (AJOL)

DELL

cause very rarely is fungal. Five types of infected .... The patient later developed ischemic symptoms in his right leg with intermittent claudication. He had to .... Salmonella species. Few cases of aneurysm caused by Tb have been described. Our cases have presented with abdominal pain, pulsating mass and a bruit. Our first.

Intermittent heating of buildings

Energy Technology Data Exchange (ETDEWEB)

Kohonen, K

1983-02-01

Conditions for intermittent heating of buildings are considered both theoretically and experimentally. Thermal behaviour of buildings adn rooms in intermittent heating is simulated by a program based on the convective heat balance equation and by simplified RC-models. The preheat times and the heating energy savings compared with continuous heating are presented for typical lightweight, mediumweight and heavyweight classroom and office modules. Formulaes for estimating the oversizing of the radiator network, the maximum heat output of heat exchangers in district heating and the efficiency of heating boilers in intermittent heating are presented. The preheat times and heating energy savings with different heating control systems are determined also experimentally in eight existing buildings. In addition some principles for the planning and application of intermittent heating systems are suggested.

ANESTHETIC MANAGEMENT FOR A PATIENT WITH ACUTE INTERMITTENT PORPHYRIA

Directory of Open Access Journals (Sweden)

Nenad Savić

2010-09-01

Full Text Available Acute intermittent porphyria is a rare metabolic disorder resulting from a partial deficiency of porphobilinogen deaminase, enzyme in the heme biosynthetic pathway. Its inheritance is autosomal dominant. A deficiency of porphobilinogen deaminase is not sufficient by its self to produce acute intermittent porphyria, and other activating factors must also be present. These include some drugs, hormones, infection, injury and alcohol. Besides others, anesthetics have been implicated in the triggering of a number of severe porphyric reactions. Although there is no clinical evidence, the fear of hypothesized porphyrinogenicity of repetitive anesthetics exposures still remains. Despite these doubts, we report here the case of uneventful repeated exposure to anesthetics in a patient suffering from acute intermittent porphyria, within a fifteen- month period. On both occasions, the patient was safely exposed to certain anesthetics included: propofol, sevoflurane, rocuronium, midazolam and fentanyl.

Intermittent Domestic Water Supply: A Critical Review and Analysis of Causal-Consequential Pathways

Directory of Open Access Journals (Sweden)

S. E. Galaitsi

2016-06-01

Full Text Available Communities in many parts of the world, especially in developing countries, face obstacles in supplying continuous water to household consumers. Authorities often cite water scarcity as the cause, but we demonstrate that environmental constraints constitute only one aspect of a multi-dimensional problem. By asking what causes intermittent domestic water supply, this literature review (129 articles identifies 47 conditions of intermittent systems and the causal-consequential pathways between them that can reinforce intermittency. These pathways span several disciplines including engineering, government administration and anthropology, and when viewed together they (1 emphasize the human drivers of intermittency; (2 suggest generalized interventions; and (3 reveal a gap in the literature in terms of meaningful categorizations of the reliability of intermittent supplies. Based on the reliability of consumers’ water access, we propose three categories of intermittency—predictable, irregular, and unreliable—to facilitate comparisons between case studies and transfers of solutions.

Multidimensional intermittency in hadronic collisions

International Nuclear Information System (INIS)

Pan, J.; Hwa, R.C.

1992-06-01

The study of intermittency in high-energy hadronic collisions by the Monte Carlo code ECCO is extended to 3-dimensional phase space. Strong intermittency is found in agreement with the data. Fluctuation in the impact parameter is responsible for the intermittency in lnp T , and the transverse-momentum conservation leads to negative intermittency slopes in the azimuthal angle φ. The Ochs-Wosiek plots are linear in all dimensions having universal slopes. An exponent ν = 1.448 emerges to characterize multiparticle production in pp collisions. The properties of G moments are also examined, and the fractal dimensions determined

Intermittency in branching models

International Nuclear Information System (INIS)

Chiu, C.B.; Texas Univ., Austin; Hwa, R.C.; Oregon Univ., Eugene

1990-01-01

The intermittency properties of three branching models have been investigated. The factorial moments show power-law behavior as function of small rapidity width. The slopes and energy dependences reveal different characteristics of the models. The gluon model has the weakest intermittency. (orig.)

One-Year Outcomes Following Directional Atherectomy of Infrapopliteal Artery Lesions: Subgroup Results of the Prospective, Multicenter DEFINITIVE LE Trial.

Science.gov (United States)

Rastan, Aljoscha; McKinsey, James F; Garcia, Lawrence A; Rocha-Singh, Krishna J; Jaff, Michael R; Noory, Elias; Zeller, Thomas

2015-12-01

To report a subgroup analysis of the prospective, multicenter, single-arm DEFINITIVE LE trial to assess the effectiveness of directional atherectomy for the treatment of infrapopliteal artery lesions at 1 year. In the DEFINITIVE LE trial, follow-up assessments occurred up to 1 year postprocedure. Of the 800 patients enrolled, 145 subjects with 189 infrapopliteal lesions met the criteria for this analysis. Seventy (48.3%) and 75 (51.7%) patients were suffering critical limb ischemia (CLI) and intermittent claudication, respectively; 68.3% (99/145) had diabetes. The mean lesion length was 58±44 mm (all lesions); 20.2% were occluded. The primary endpoint for patients with claudication was duplex ultrasound-derived primary patency, while for subjects with CLI it was freedom from major amputation of the target limb at 1 year. Endpoints and adverse events were independently assessed. Procedure success (≤30% residual stenosis) was achieved in 84% of treated lesions. The 1-year primary patency rate was 84% (claudicants 89.6% and CLI patients 78%, p=0.11), and the freedom from major amputation rate was 97.1% (claudicants 100% and CLI 93.8%, p=0.03). In both claudication and CLI patients, significant improvements in Rutherford category and objective measures of walking distance and quality of life were seen at 1 year in comparison to baseline. This study demonstrates that directional atherectomy in infrapopliteal arteries results in promising technical and clinical results at 1 year for claudicant as well as CLI patients. © The Author(s) 2015.

Development of quality indicators for physiotherapy for patients with PAOD in the Netherlands: a Delphi study.

Science.gov (United States)

Gijsbers, H J H; Lauret, G J; van Hofwegen, A; van Dockum, T A; Teijink, J A W; Hendriks, H J M

2016-06-01

The aim of the study was to develop quality indicators (QIs) for physiotherapy management of patients with intermittent claudication (IC) in the Netherlands. As part of an international six-step method to develop QIs, an online survey Delphi-procedure was completed. After two Delphi-rounds a validation round was performed. Twenty-six experts were recruited to participate in this study. Twenty-four experts completed two Delphi-rounds. A third round was conducted inviting 1200 qualified and registered physiotherapists of the Dutch integrated care network 'Claudicationet' to validate a draft set of quality indicators. Out of 83 potential QIs in the Dutch physiotherapy guideline on 'Intermittent claudication', consensus among the experts selected nine indicators. All nine quality indicators were validated by 300 physiotherapists. A final set of nine indicators was derived from (1) a Dutch evidence-based physiotherapy guideline, (2) an expert Delphi procedure and (3) a validation by 300 physiotherapists. This set of indicators should be validated in clinical practice. Copyright © 2015 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

Evolution of surgical techniques for a progressive risk reduction.

Science.gov (United States)

Amato, Bruno; Santoro, Mario; Izzo, Raffaele; Servillo, Giuseppe; Compagna, Rita; Di Domenico, Lorenza; Di Nardo, Veronica; Giugliano, Giuseppe

2017-07-18

Advanced age is a strong predictor of high perioperative mortality in surgical patients and patients aged 75 years and older have an elevated surgical risk, much higher than that of younger patients. Progressive advances in surgical techniques now make it possible to treat high-risk surgical patients with minimally invasive procedures. Endovascular techniques have revolutionized the treatment of several vascular diseases, in particular carotid stenosis, aortic pathologies, and severely incapacitating intermittent claudication or critical limb ischemia. The main advantages of the endovascular approach are the low complication rate, high rate of technical success and a good clinical outcome. Biliary stenting has improved the clinical status of severely ill patients with bile duct stricture before major surgery, and represents a good palliative therapy in the case of malignant biliary obstruction.

Bilateral paracoccidioidomycotic iliopsoas abscess associated with ileo-colonic lesion

Directory of Open Access Journals (Sweden)

Helena Duani

2012-10-01

Full Text Available This case report shows the clinical development of a patient with systemic paracoccidioidomycosis presenting with lymphatic-intestinalmanifestation. The patient initially had a substantial clinical improvement but had a recrudescence after six months of sulfamethoxazoletrimethoprim oral treatment, with the emergence of feverish syndrome, lumbar pain, and intermittent claudication, characterizing a bilateral iliopsoas muscle abscess, necessitating clinicosurgical therapeutics.

Cosmic Rays in Intermittent Magnetic Fields

International Nuclear Information System (INIS)

Shukurov, Anvar; Seta, Amit; Bushby, Paul J.; Wood, Toby S.; Snodin, Andrew P.

2017-01-01

The propagation of cosmic rays in turbulent magnetic fields is a diffusive process driven by the scattering of the charged particles by random magnetic fluctuations. Such fields are usually highly intermittent, consisting of intense magnetic filaments and ribbons surrounded by weaker, unstructured fluctuations. Studies of cosmic-ray propagation have largely overlooked intermittency, instead adopting Gaussian random magnetic fields. Using test particle simulations, we calculate cosmic-ray diffusivity in intermittent, dynamo-generated magnetic fields. The results are compared with those obtained from non-intermittent magnetic fields having identical power spectra. The presence of magnetic intermittency significantly enhances cosmic-ray diffusion over a wide range of particle energies. We demonstrate that the results can be interpreted in terms of a correlated random walk.

Cosmic Rays in Intermittent Magnetic Fields

Energy Technology Data Exchange (ETDEWEB)

Shukurov, Anvar; Seta, Amit; Bushby, Paul J.; Wood, Toby S. [School of Mathematics and Statistics, Newcastle University, Newcastle Upon Tyne NE1 7RU (United Kingdom); Snodin, Andrew P., E-mail: a.seta1@ncl.ac.uk, E-mail: amitseta90@gmail.com [Department of Mathematics, Faculty of Applied Science, King Mongkut’s University of Technology North Bangkok, Bangkok 10800 (Thailand)

2017-04-10

The propagation of cosmic rays in turbulent magnetic fields is a diffusive process driven by the scattering of the charged particles by random magnetic fluctuations. Such fields are usually highly intermittent, consisting of intense magnetic filaments and ribbons surrounded by weaker, unstructured fluctuations. Studies of cosmic-ray propagation have largely overlooked intermittency, instead adopting Gaussian random magnetic fields. Using test particle simulations, we calculate cosmic-ray diffusivity in intermittent, dynamo-generated magnetic fields. The results are compared with those obtained from non-intermittent magnetic fields having identical power spectra. The presence of magnetic intermittency significantly enhances cosmic-ray diffusion over a wide range of particle energies. We demonstrate that the results can be interpreted in terms of a correlated random walk.

The organ specificity in pathological damage of chronic intermittent hypoxia: an experimental study on rat with high-fat diet.

Science.gov (United States)

Wang, Hui; Tian, Jian-li; Feng, Shu-zhi; Sun, Ning; Chen, Bao-yuan; Zhang, Yun

2013-09-01

It is known today that sleep apnea hypopnea syndrome and its characteristic chronic intermittent hypoxia can cause damages to multiple organs, including the cardiovascular system, urinary system, and liver. It is still unclear, however, whether the damage caused by sleep apnea hypopnea syndrome and the severity of the damage are organ-specific. This research observed the pathological effects of chronic intermittent hypoxia on rat's thoracic aorta, myocardium, liver, and kidney, under the condition of lipid metabolism disturbance, through establishing the rat model of chronic intermittent hypoxia with high-fat diet by imitating the features of human sleep apnea hypopnea syndrome. In this model, 24 male Wistar rats were randomly divided into three groups: a control group fed by regular diet, a high-fat group fed by high-fat diet, and a high-fat plus intermittent hypoxia group fed by high-fat diet and treated with intermittent hypoxia 7 h a day. At the end of the ninth week, the pathological changes of rat's organs, including the thoracic aorta, myocardium, liver, and kidney are observed (under both optical microscopy and transmission electron microscopy). As the result of the experiment shows, while there was no abnormal effect observed on any organs of the control group, slight pathological changes were found in the organs of the high-fat group. For the high-fat plus intermittent hypoxia group, however, remarkably severer damages were found on all the organs. It also showed that the severity of the damage varies by organ in the high-fat plus intermittent hypoxia group, with the thoracic aorta being the worst, followed by the liver and myocardium, and the kidney being the slightest. Chronic intermittent hypoxia can lead to multiple-organ damage to rat with high-fat diet. Different organs appear to have different sensitivity to chronic intermittent hypoxia.

Multistate intermittency on the route to chaos of a semiconductor laser subjected to optical feedback from a long external cavity.

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Choi, Daeyoung; Wishon, Michael J; Chang, C Y; Citrin, D S; Locquet, A

2018-01-01

We observe experimentally two regimes of intermittency on the route to chaos of a semiconductor laser subjected to optical feedback from a long external cavity as the feedback level is increased. The first regime encountered corresponds to multistate intermittency involving two or three states composed of several combinations of periodic, quasiperiodic, and subharmonic dynamics. The second regime is observed for larger feedback levels and involves intermittency between period-doubled and chaotic regimes. This latter type of intermittency displays statistical properties similar to those of on-off intermittency.

Computing moving and intermittent queue propagation in highway work zones.

Science.gov (United States)

2012-07-01

Drivers may experience intermittent congestion and moving queue conditions in work zones due to several reasons such as presence of lane closure, roadway geometric changes, higher demand, lower speed, and reduced capacity. The congestion and queue ha...

Exercise in claudicants increase or decrease walking ability and the response relates to mitochondrial function.

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van Schaardenburgh, Michel; Wohlwend, Martin; Rognmo, Øivind; Mattsson, Erney J R

2017-06-07

Exercise of patients with intermittent claudication improves walking performance. Exercise does not usually increase blood flow, but seems to increase muscle mitochondrial enzyme activities. Although exercise is beneficial in most patients, it might be harmful in some. The mitochondrial response to exercise might therefore differ between patients. Our hypothesis was that changes in walking performance relate to changes in mitochondrial function after 8 weeks of exercise. At a subgroup level, negative responders decrease and positive responders increase mitochondrial capacity. Two types of exercise were studied, calf raising and walking (n = 28). We wanted to see whether there were negative and positive responders, independent of type of exercise. Measurements of walking performance, peripheral hemodynamics, mitochondrial respiration and content (citrate synthase activity) were obtained on each patient before and after the intervention period. Multiple linear regression was used to test whether changes in peak walking time relate to mitochondrial function. Subgroups of negative (n = 8) and positive responders (n = 8) were defined as those that either decreased or increased peak walking time following exercise. Paired t test and analysis of covariance was used to test changes within and between subgroups. Changes in peak walking time were related to changes in mitochondrial respiration supported by electron transferring flavoprotein (ETF + CI) P (p = 0.004), complex I (CI + ETF) P (p = 0.003), complex I + complex II (CI + CII + ETF) P (p = 0.037) and OXPHOS coupling efficiency (p = 0.046) in the whole group. Negative responders had more advanced peripheral arterial disease. Mitochondrial respiration supported by electron transferring flavoprotein (ETF + CI) P (p = 0.0013), complex I (CI + ETF) P (p = 0.0005), complex I + complex II (CI + CII + ETF) P (p = 0.011) and electron transfer system capacity (CI + CII + ETF) E (p

Induction of Severe Chronic Hyperplastic Candidiasis in Rat by Opportunistic Infection of C. albicans through Combination of Diabetes and Intermittent Prednisolone Administration.

Science.gov (United States)

Terayama, Yui; Matsuura, Tetsuro; Ozaki, Kiyokazu

2017-08-01

Chronic hyperplastic candidiasis progresses from squamous cell hyperplasia to squamous cell carcinoma (SCC); however, the oncogenic mechanism remains unclear. In the present study, we attempted to induce opportunistic Candida albicans infection and establish chronic hyperplastic candidiasis in rats by combining diabetic condition and prednisolone administration, followed by analysis of the inflammatory cells involved in the disease progression. Female Wistar Bunn/Kobori (WBN/Kob) rats were divided into 3 groups: alloxan-induced diabetic rats (A group) along with diabetic (AP group) and nondiabetic (P group) rats intermittently treated with prednisolone. Animals were euthanized at 42 weeks of age. Squamous cell hyperplasia following C. albicans infection in the forestomach was observed in almost all AP and A group rats. The lesions in the AP group were significantly more severe than those in the A group. In addition, SCC was detected in 1 AP group animal. Cluster of differentiation (CD)4-positive T cell and CD68-positive macrophage infiltration in the AP group was significantly stronger than that in the A group. These findings suggest that the combination of diabetes and intermittent prednisolone administration could induce chronic hyperplastic candidiasis without direct C. albicans inoculation and that CD4-positive T cells and CD68-positive macrophages may be highly involved in the pathogenesis of these hyperplastic lesions.

Randomized, controlled trial comparing synchronized intermittent mandatory ventilation and synchronized intermittent mandatory ventilation plus pressure support in preterm infants.

Science.gov (United States)

Reyes, Zenaida C; Claure, Nelson; Tauscher, Markus K; D'Ugard, Carmen; Vanbuskirk, Silvia; Bancalari, Eduardo

2006-10-01

Prolonged mechanical ventilation is associated with lung injury in preterm infants. In these infants, weaning from synchronized intermittent mandatory ventilation may be delayed by their inability to cope with increased respiratory loads. The addition of pressure support to synchronized intermittent mandatory ventilation can offset these loads and may facilitate weaning. The purpose of this work was to compare synchronized intermittent mandatory ventilation and synchronized intermittent mandatory ventilation plus pressure support in weaning from mechanical ventilation and the duration of supplemental oxygen dependency in preterm infants with respiratory failure. Preterm infants weighing 500 to 1000 g at birth who required mechanical ventilation during the first postnatal week were randomly assigned to synchronized intermittent mandatory ventilation or synchronized intermittent mandatory ventilation plus pressure support. In both groups, weaning followed a set protocol during the first 28 days. Outcomes were assessed during the first 28 days and until discharge or death. There were 107 infants enrolled (53 synchronized intermittent mandatory ventilation plus pressure support and 54 synchronized intermittent mandatory ventilation). Demographic and perinatal data, mortality, and morbidity did not differ between groups. During the first 28 days, infants in the synchronized intermittent mandatory ventilation plus pressure support group reached minimal ventilator settings and were extubated earlier than infants in the synchronized intermittent mandatory ventilation group. Total duration of mechanical ventilation, duration of oxygen dependency, and oxygen need at 36 weeks' postmenstrual age alone or combined with death did not differ between groups. However, infants in synchronized intermittent mandatory ventilation plus pressure support within the 700- to 1000-g birth weight strata had a shorter oxygen dependency. The results of this study suggest that the addition of

Intermittency in 197Au fragmentation

International Nuclear Information System (INIS)

Dabrowska, A.; Holynski, R.; Olszewski, A.; Szarska, M.; Wilczynska, B.; Wolter, W.; Wosiek, B.; Cherry, M.L.; Deines-Jones, P.; Jones, W.V.; Sengupta, K.; Wefel, B.

1995-07-01

The concept of factorial moments was applied to an analysis of the dynamical fluctuations in the charge distributions of the fragments emitted from gold nuclei with energies 10.6 and < 1.0 GeV/n interacting with emulsion nuclei. Clear evidence for intermittent fluctuations has been found in an analysis using all the particles released from the gold projectile, with a stronger effect observed below 1 GeV/n than at 10.6 GeV/n. For the full data sets, however, the intermittency effect was found to be very sensitive to the singly charged particles, and neglecting these particles strongly reduces the intermittency signal. When the analysis is restricted to the multiply charged fragments, an intermittency effect is revealed only for multifragmentation events, although one that is enhanced as compared to the analysis of all, singly and multiply charged, particles. The properties of the anomalous fractal dimensions suggest a sequential decay mechanism, rather than the existence of possible critical behaviour in the process of nuclear fragmentation. The likely influence of the charge conservation effects and the finite size of decaying systems on the observed intermittency signals was pointed out. (author). 37 refs, 9 figs, 5 tabs

Intermittent control: a computational theory of human control.

Science.gov (United States)

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

2011-02-01

The paradigm of continuous control using internal models has advanced understanding of human motor control. However, this paradigm ignores some aspects of human control, including intermittent feedback, serial ballistic control, triggered responses and refractory periods. It is shown that event-driven intermittent control provides a framework to explain the behaviour of the human operator under a wider range of conditions than continuous control. Continuous control is included as a special case, but sampling, system matched hold, an intermittent predictor and an event trigger allow serial open-loop trajectories using intermittent feedback. The implementation here may be described as "continuous observation, intermittent action". Beyond explaining unimodal regulation distributions in common with continuous control, these features naturally explain refractoriness and bimodal stabilisation distributions observed in double stimulus tracking experiments and quiet standing, respectively. Moreover, given that human control systems contain significant time delays, a biological-cybernetic rationale favours intermittent over continuous control: intermittent predictive control is computationally less demanding than continuous predictive control. A standard continuous-time predictive control model of the human operator is used as the underlying design method for an event-driven intermittent controller. It is shown that when event thresholds are small and sampling is regular, the intermittent controller can masquerade as the underlying continuous-time controller and thus, under these conditions, the continuous-time and intermittent controller cannot be distinguished. This explains why the intermittent control hypothesis is consistent with the continuous control hypothesis for certain experimental conditions.

STUDIES ON DIABETIC FOOT ULCERS IN PATIENTS AT

African Journals Online (AJOL)

(>126 mg/ dl) for fasting blood sugar or more than 11.1 mmol/L (>200 mg/dl) 2 hours postprandial (l 1). ... The fasting blood glucose at the time of admission ranged from 6.0 mmol/L to 28 mmol/L. The packed .... Presence of intermittent claudication 37 14 36.8. Presence or nocturnal diarrhoea 38 15 39.5. Presence of ...

CONDITIONED ANALYSIS OF HIGH-LATITUDE SOLAR WIND INTERMITTENCY

International Nuclear Information System (INIS)

D'Amicis, R.; Consolini, G.; Bavassano, B.; Bruno, R.

2012-01-01

The solar wind is a turbulent medium displaying intermittency. Its intermittent features have been widely documented and studied, showing how the intermittent character is different in fast and slow wind. In this paper, a statistical conditioned analysis of the solar wind intermittency for a period of high-latitude fast solar wind is presented. In particular, the intermittent features are investigated as a function of the Alfvénic degree of fluctuations at a given scale. The results show that the main contribution to solar wind intermittency is due to non-Alfvénic structures, while Alfvénic increments are found to be characterized by a smaller level of intermittency than the previous ones. Furthermore, the lifetime statistics of Alfvénic periods are discussed in terms of a multiscale texture of randomly oriented flux tubes.

Healthcare professional versus patient goal setting in intermittent allergic rhinitis.

Science.gov (United States)

O'Connor, J; Seeto, C; Saini, B; Bosnic-Anticevich, S; Krass, I; Armour, C; Smith, L

2008-01-01

To examine the impact of healthcare professional versus patient goal setting for the self-management of intermittent allergic rhinitis (AR) on symptom severity and quality of life. This was a 6 week, parallel group study. Group A participants, with pharmacist facilitation, nominated personally relevant goals and strategies relating to their AR. Group B participants had their goals and strategies set by the pharmacist. The main outcome measures used included perceived symptom severity and quality of life. In addition, goals and strategies data from participants of both groups were collected and analysed. Both groups demonstrated significant improvements in symptom severity and quality of life scores however Group B symptom severity scores improved more. Group B set a greater number of goals and strategies which were better structured and more task specific. This is the first study to investigate the impact of goal setting on patient behaviour in a chronic yet episodic illness. Our results suggest that self-management goals set by the healthcare professional which are clinically indicated but tailored to the patient's nominated symptoms yields better outcomes than goals nominated by the patient. A brief, structured intervention, tailored to patient symptoms, can enhance self-management of intermittent allergic rhinitis.

Intermittency '93

International Nuclear Information System (INIS)

Bialas, A.

1993-01-01

The existing data definitely indicate the existence of intermittency, i.e. of self similar structures in the systems of particles created in high-energy collisions. The effect seems universal: it was found in most of the processes investigated and its measures parameters depend only weakly (if at all) on the process in question. Strong HBT effect was found, suggesting that intermittency is related to space-time structure of the pion source rather than to detailed momentum structure of the production amplitudes. There are indications that this space time structure may be fractal, but more data is needed to establish this. The theoretical explanation remains obscure: it seems that both parton cascade and hadronization play an important role. Their interrelation, however, remains a mystery. 5 figs., 19 refs

Are the barriers for physical activity practice equal for all peripheral artery disease patients?

Science.gov (United States)

Cavalcante, Bruno R; Farah, Breno Q; dos A Barbosa, João Paulo; Cucato, Gabriel Grizzo; da Rocha Chehuen, Marcel; da Silva Santana, Fábio; Wolosker, Nelson; de Moraes Forjaz, Cláudia Lúcia; Ritti-Dias, Raphael M

2015-02-01

To investigate barriers to physical activity related to the sociodemographic comorbidities and clinical variables of patients with intermittent claudication. Cross-sectional study. Ambulatory care. The medical histories of patients (N=145) aged ≥50 years with intermittent claudication were examined. Not applicable. Sociodemographic data (sex, race, level of education, socioeconomic status, marital status), comorbidities (overweight, hypertension, dyslipidemia, diabetes, currently smoking, heart disease), and clinical variables (initial claudication distance, total walking distance, ankle-brachial index). Information on personal and environmental barriers was obtained by questionnaire. Low economic status was most associated with "being afraid of falling" (odd ratios [OR]=2.22; 95% confidence interval [CI], 1.08-4.54). Low education level was most associated with "lack of street pedestrian crossing" (OR=3.34; 95% CI, 1.48-7.52). Diabetes was associated with lack of energy (OR=3.38; 95% CI, 1.68-6.79) and other medical conditions (eg, arthritis, angina) (OR=3.44; 95% CI, 1.65-7.16). Ankle brachial index was associated with "some difficulty in getting to a place where physical activity can be performed" (OR=2.75; 95% CI, 1.22-6.21). Walking capacity was strongly associated with barriers relating to leg pain (OR=7.39; 95% CI, 1.66-32.88). Older patients, those with a low education level, patients with diabetes, low ankle brachial index, and those with a lower walking capacity are more likely to experience barriers to physical activity. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Optimal Intermittent Operation of Water Distribution Networks under Water Shortage

Directory of Open Access Journals (Sweden)

mohamad Solgi

2017-07-01

Full Text Available Under water shortage conditions, it is necessary to exercise water consumption management practices in water distribution networks (WDN. Intermittent supply of water is one such practice that makes it possible to supply consumption nodal demands with the required pressure via water cutoff to some consumers during certain hours of the day. One of the most important issues that must be observed in this management practice is the equitable and uniform water distribution among the consumers. In the present study, uniformity in water distribution and minimum supply of water to all consumers are defined as justice and equity, respectively. Also, an optimization model has been developed to find an optimal intermittent supply schedule that ensures maximum number of demand nodes are supplied with water while the constraints on the operation of water distribution networks are also observed. To show the efficiency of the proposed model, it has been used in the Two-Loop distribution network under several different scenarios of water shortage. The optimization model has been solved using the honey bee mating optimization algorithm (HBMO linked to the hydraulic simulator EPANET. The results obtained confirm the efficiency of the proposed model in achieving an optimal intermittent supply schedule. Moreover, the model is found capable of distributing the available water in an equitable and just manner among all the consumers even under severe water shoratges.

Impact of Chronic Neonatal Intermittent Hypoxia on Severity of Retinal Damage in a Rat Model of Oxygen-Induced Retinopathy.

Science.gov (United States)

Beharry, Kay D; Cai, Charles L; Ahmad, Taimur; Guzel, Sibel; Valencia, Gloria B; Aranda, Jacob V

2018-01-01

Neonatal intermittent hypoxia (IH) followed by re-oxygenation in normoxia or supplemental oxygen (IHR) increases the risk for severe retinopathy of prematurity (ROP). The exact timing for the onset of retinal damage which may guide strategic interventions during retinal development, is unknown. We tested the hypothesis that chronic exposure of the immature retina to neonatal IH induces early manifestations of retinal damage that can be utilized as key time points for strategic pharmacologic intervention. Newborn rats were exposed to IH within 2 hours of birth (P0) until P14, or allowed to recover in room air (RA) from P14 to P21 (IHR). Retinal integrity and angiogenesis biomarkers were progressively assessed before (P0), during IH, and post IH (recovery in RA), or IHR, and compared to normoxic age-matched controls. Retinal damage occurred as early as day 3 of neonatal IH, consistent with vascular abnormalities and disturbances in the astrocytic template. These abnormalities worsened during IHR. Pharmacologic and non-pharmacologic interventions to identify, prevent, or minimize neonatal IH should be implemented shortly after birth in high risk preterm newborns. This strategy may lead to a reduction in the outcome of severe ROP requiring later invasive treatments.

The impact of coronary artery disease and left ventricular ejection fraction on the prognosis of patients with peripheral artery disease.

Science.gov (United States)

Tsujimura, Takuya; Iida, Osamu; Ishihara, Takayuki; Fujita, Masashi; Masuda, Masaharu; Okamoto, Shin; Nanto, Kiyonori; Kanda, Takashi; Sunaga, Akihiro; Takahara, Mitsuyoshi; Uematsu, Masaaki

2017-11-01

The impact of the severity of coronary artery disease (CAD) and left ventricular ejection fraction (LVEF) on the prognosis of patients with peripheral artery disease (PAD) has not been systematically studied. We retrospectively analysed 622 patients with PAD (intermittent claudication (IC): n = 446; critical limb ischaemia (CLI): n = 176). The association of SYNTAX score and LVEF with mortality was analysed using the Cox proportional hazard model. In patients with IC, a high SYNTAX score was significantly associated with mortality, whereas reduced LVEF was significantly associated with mortality in patients with CLI. The prognostic impact of CAD and LVEF appears different between patients with IC and CLI. © 2017 Royal Australasian College of Physicians.

Effects of intermittent feeding of tylosin phosphate during the finishing period on feedlot performance, carcass characteristics, antimicrobial resistance, and incidence and severity of liver abscesses in steers.

Science.gov (United States)

Müller, H C; Van Bibber-Krueger, C L; Ogunrinu, O J; Amachawadi, R G; Scott, H M; Drouillard, J S

2018-04-27

Liver abscesses (LA) are a source of economic loss for feedlot cattle feedlots, and the 2017 veterinary feed directive has restricted further use of tylosin phosphate to prevention and control of LA. Our objective was to evaluate effects of intermittent tylosin phosphate feeding on incidence and severity of liver abscesses in feedlot cattle and presence of total antimicrobial resistant Enterococcus spp. Steers (n=312, 411.4 ± 6.71 kg) were blocked by initial BW and randomly assigned to a treatment group. Treatments included a negative control group (no tylosin phosphate throughout the finishing period), a positive control group (tylosin phosphate fed continuously throughout the finishing period), and a group that received tylosin phosphate off-label by feeding the drug on a repeated intermittent basis (1 week on, 2 weeks off). Steers were housed in 24 soil-surfaced pens with 13 steers per pen. Bodyweights of cattle were obtained every 28 d and at the end of 119 d the steers were weighed and harvested at a commercial abattoir. Fecal samples were collected on day 0, 21, and 118 to characterize antimicrobial resistant Enterococcus spp. Total LA percentage was greater (P = 0.012) for the no tylosin phosphate treatment compared to the other treatments, but did not differ between the continuous tylosin phosphate treatment and the intermittently fed tylosin phosphate treatment (P = 0.716). No difference was observed among treatments for ADG (P = 0.21), DMI (P = 0.28), or G:F (P = 0.75). Marbling score was lower (P = 0.022) for tylosin phosphate treatment when compared both to intermittent treatment and continuous tylosin phosphate treatment. Enterococcus spp. bacterial counts did not differ by treatment group over time (P > 0.05); however, there was a strong period effect for macrolide resistance among all groups (P feeding period. We conclude that feeding tylosin phosphate intermittently during the finishing phase decreases the total percentage of LA and maintains

Obstructive sleep apnea and intermittent hypoxia increase expression of dual specificity phosphatase 1.

Science.gov (United States)

Hoffmann, Michal S; Singh, Prachi; Wolk, Robert; Narkiewicz, Krzysztof; Somers, Virend K

2013-12-01

Dual specificity phosphatase 1 (DUSP1) inhibits mitogen activated protein kinase activity, and is activated by several stimuli such as sustained hypoxia, oxidative stress, and hormones. However, the effect of intermittent hypoxia is not known. The aim of this study was to evaluate the role of intermittent hypoxia on DUSP1 expression, and to validate its role in a human model of intermittent hypoxia, as seen in obstructive sleep apnea (OSA). OSA is characterized by recurrent episodes of hypoxemia/reoxygenation and is a known risk factor for cardiovascular morbidity. In-vitro studies using human coronary artery endothelial cells (HCAEC) and ex-vivo studies using white blood cells isolated from healthy and OSA subjects. Intermittent hypoxia induced DUSP1 expression in human coronary artery endothelial cells (HCAEC), and in granulocytes isolated from healthy human subjects. Functionally, DUSP1 increased the expression and activity of manganese superoxide dismutase (MnSOD) in HCAEC. Further, significant increases in DUSP1 mRNA from total blood, and in DUSP1 protein in mononuclear cells and granulocytes isolated from OSA subjects, were observed in the early morning hours after one night of intermittent hypoxemia due to untreated OSA. This early-morning OSA-induced augmentation of DUSP1 gene expression was attenuated by continuous positive airway pressure (CPAP) treatment of OSA. Intermittent hypoxia increases MnSOD activity via increased DUSP1 expression in HCAEC. Similarly, overnight intermittent hypoxemia in patients with OSA induces expression of DUSP1, which may mediate increases of MnSOD expression and activity. This may contribute significantly to neutralizing the effects of reactive oxygen species, a consequence of the intermittent hypoxemia/reperfusion elicited by OSA. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Pressure Autoregulation Measurement Techniques in Adult Traumatic Brain Injury, Part I: A Scoping Review of Intermittent/Semi-Intermittent Methods.

Science.gov (United States)

Zeiler, Frederick A; Donnelly, Joseph; Calviello, Leanne; Menon, David K; Smielewski, Peter; Czosnyka, Marek

2017-12-01

The purpose of this study was to perform a systematic, scoping review of commonly described intermittent/semi-intermittent autoregulation measurement techniques in adult traumatic brain injury (TBI). Nine separate systematic reviews were conducted for each intermittent technique: computed tomographic perfusion (CTP)/Xenon-CT (Xe-CT), positron emission tomography (PET), magnetic resonance imaging (MRI), arteriovenous difference in oxygen (AVDO 2 ) technique, thigh cuff deflation technique (TCDT), transient hyperemic response test (THRT), orthostatic hypotension test (OHT), mean flow index (Mx), and transfer function autoregulation index (TF-ARI). MEDLINE ® , BIOSIS, EMBASE, Global Health, Scopus, Cochrane Library (inception to December 2016), and reference lists of relevant articles were searched. A two tier filter of references was conducted. The total number of articles utilizing each of the nine searched techniques for intermittent/semi-intermittent autoregulation techniques in adult TBI were: CTP/Xe-CT (10), PET (6), MRI (0), AVDO 2 (10), ARI-based TCDT (9), THRT (6), OHT (3), Mx (17), and TF-ARI (6). The premise behind all of the intermittent techniques is manipulation of systemic blood pressure/blood volume via either chemical (such as vasopressors) or mechanical (such as thigh cuffs or carotid compression) means. Exceptionally, Mx and TF-ARI are based on spontaneous fluctuations of cerebral perfusion pressure (CPP) or mean arterial pressure (MAP). The method for assessing the cerebral circulation during these manipulations varies, with both imaging-based techniques and TCD utilized. Despite the limited literature for intermittent/semi-intermittent techniques in adult TBI (minus Mx), it is important to acknowledge the availability of such tests. They have provided fundamental insight into human autoregulatory capacity, leading to the development of continuous and more commonly applied techniques in the intensive care unit (ICU). Numerous methods of

TST, as a polysomnographic variable, is superior to the apnea hypopnea index for evaluating intermittent hypoxia in severe obstructive sleep apnea.

Science.gov (United States)

Zhang, Xiao-Bin; Zen, Hui-Qing; Lin, Qi-Chang; Chen, Gong-Ping; Chen, Li-Da; Chen, Hua

2014-10-01

The polysomnography (PSG) index of the apnea hypopnea index (AHI) is considered the 'gold standard' for stratifying the severity of obstructive sleep apnea (OSA). However, AHI cannot reflect the true characteristic of chronic intermittent hypoxia (CIH), which may trigger systemic inflammation in some OSA patients. High-sensitivity C-reactive protein (hsCRP) is considered a biomarker of systemic inflammation in OSA patients. The aim of the present study was to evaluate the relationship between PSG variables and hsCRP in men with severe OSA. Men with severe OSA (AHI ≥ 30 events/h) diagnosed by PSG were enrolled. AHI and body mass index were matched between a high hsCRP group (hsCRP ≥ 3.0 mg/L) and a low hsCRP group. A blood sample was taken for serum hsCRP analysis. Multiple regression analysis was performed to assess independent predictors of high hsCRP. One hundred and fifty-two subjects were enrolled in the study (76 in each group). Mean serum hsCRP was 3.76 ± 2.13 mg/L. The mean percentage of total sleep time spent with SaO2 hypoxia variables.

Optimal intermittent search strategies

International Nuclear Information System (INIS)

Rojo, F; Budde, C E; Wio, H S

2009-01-01

We study the search kinetics of a single fixed target by a set of searchers performing an intermittent random walk, jumping between different internal states. Exploiting concepts of multi-state and continuous-time random walks we have calculated the survival probability of a target up to time t, and have 'optimized' (minimized) it with regard to the transition probability among internal states. Our model shows that intermittent strategies always improve target detection, even for simple diffusion states of motion

Intermittency in {sup 197}Au fragmentation

Energy Technology Data Exchange (ETDEWEB)

Dabrowska, A; Holynski, R; Olszewski, A; Szarska, M; Wilczynska, B; Wolter, W; Wosiek, B [Institute of Nuclear Physics, Cracow (Poland); Cherry, M L; Deines-Jones, P; Jones, W V; Sengupta, K; Wefel, B [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Physics and Astronomy; Waddington, C J [Minnesota Univ., Minneapolis, MN (United States). School of Physics and Astronomy; Pozharova, E A; Skorodko, T Yu [Inst. of Theoretical and Experimental Physics, Moscow (Russian Federation); KLMM Collaboration

1995-07-01

The concept of factorial moments was applied to an analysis of the dynamical fluctuations in the charge distributions of the fragments emitted from gold nuclei with energies 10.6 and < 1.0 GeV/n interacting with emulsion nuclei. Clear evidence for intermittent fluctuations has been found in an analysis using all the particles released from the gold projectile, with a stronger effect observed below 1 GeV/n than at 10.6 GeV/n. For the full data sets, however, the intermittency effect was found to be very sensitive to the singly charged particles, and neglecting these particles strongly reduces the intermittency signal. When the analysis is restricted to the multiply charged fragments, an intermittency effect is revealed only for multifragmentation events, although one that is enhanced as compared to the analysis of all, singly and multiply charged, particles. The properties of the anomalous fractal dimensions suggest a sequential decay mechanism, rather than the existence of possible critical behaviour in the process of nuclear fragmentation. The likely influence of the charge conservation effects and the finite size of decaying systems on the observed intermittency signals was pointed out. (author). 37 refs, 9 figs, 5 tabs.

Optimal intermittent search strategies

Energy Technology Data Exchange (ETDEWEB)

Rojo, F; Budde, C E [FaMAF, Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina); Wio, H S [Instituto de Fisica de Cantabria, Universidad de Cantabria and CSIC E-39005 Santander (Spain)

2009-03-27

We study the search kinetics of a single fixed target by a set of searchers performing an intermittent random walk, jumping between different internal states. Exploiting concepts of multi-state and continuous-time random walks we have calculated the survival probability of a target up to time t, and have 'optimized' (minimized) it with regard to the transition probability among internal states. Our model shows that intermittent strategies always improve target detection, even for simple diffusion states of motion.

Accommodative spasm with bilateral vision loss due to untreated intermittent exotropia in an adult.

Science.gov (United States)

Shanker, V; Ganesh, S; Sethi, S

2012-01-01

Intermittent exotropia (IXT) is an exodeviation intermittently controlled by fusional mechanisms. Patients with IXT may present with asthenopic symptoms, blurred vision, headaches, diplopia or visual confusion and reading difficulties; especially after prolonged periods of near work. To report the presentation and management of a young adult with intractable accommodative spasm secondary to long standing intermittent exotropia. The patient was found to have bilateral accommodative spasm with high pseudomyopia and severe impairment of vision. There was a tendency for recurrence with discontinuation of cycloplegics. A total relief of symptoms was noticed after strabismus surgery was undertaken for the exotropia. A detailed orthoptic evaluation with emphasis on recognizing accommodative spasm as an unusual presentation of IXT, could aid in appropriate diagnosis and treatment of such cases. © NEPjOPH.

Intermittent Rivers and Biodiversity. Large scale analyses between hydrology and ecology in intermittent rivers

OpenAIRE

Blanchard, Q.

2014-01-01

Intermittent rivers are characterized by a temporary interruption of their flow which can manifest in a variety of ways, as much on a spatial scale as on a temporal one. This particular aspect of intermittent river hydrology gives rise to unique ecosystems, combining both aquatic and terrestrial habitats. Neglected for a long time by scientists and once considered biologically depauperate and ecologically unimportant, these fragile habitats are nowadays acknowledged for their rendered service...

Method for assessing the probability of accumulated doses from an intermittent source using the convolution technique

International Nuclear Information System (INIS)

Coleman, J.H.

1980-10-01

A technique is discussed for computing the probability distribution of the accumulated dose received by an arbitrary receptor resulting from several single releases from an intermittent source. The probability density of the accumulated dose is the convolution of the probability densities of doses from the intermittent releases. Emissions are not assumed to be constant over the brief release period. The fast fourier transform is used in the calculation of the convolution

Positive effects of intermittent fasting in ischemic stroke.

Science.gov (United States)

Fann, David Yang-Wei; Ng, Gavin Yong Quan; Poh, Luting; Arumugam, Thiruma V

2017-03-01

Intermittent fasting (IF) is a dietary protocol where energy restriction is induced by alternate periods of ad libitum feeding and fasting. Prophylactic intermittent fasting has been shown to extend lifespan and attenuate the progress and severity of age-related diseases such as cardiovascular (e.g. stroke and myocardial infarction), neurodegenerative (e.g. Alzheimer's disease and Parkinson's disease) and cancerous diseases in animal models. Stroke is the second leading cause of death, and lifestyle risk factors such as obesity and physical inactivity have been associated with elevated risks of stroke in humans. Recent studies have shown that prophylactic IF may mitigate tissue damage and neurological deficit following ischemic stroke by a mechanism(s) involving suppression of excitotoxicity, oxidative stress, inflammation and cell death pathways in animal stroke models. This review summarizes data supporting the potential hormesis mechanisms of prophylactic IF in animal models, and with a focus on findings from animal studies of prophylactic IF in stroke in our laboratory. Copyright © 2017 Elsevier Inc. All rights reserved.

Putting intelligent structured intermittent auscultation (ISIA) into practice.

Science.gov (United States)

Maude, Robyn M; Skinner, Joan P; Foureur, Maralyn J

2016-06-01

Fetal monitoring guidelines recommend intermittent auscultation for the monitoring of fetal wellbeing during labour for low-risk women. However, these guidelines are not being translated into practice and low-risk women birthing in institutional maternity units are increasingly exposed to continuous cardiotocographic monitoring, both on admission to hospital and during labour. When continuous fetal monitoring becomes routinised, midwives and obstetricians lose practical skills around intermittent auscultation. To support clinical practice and decision-making around auscultation modality, the intelligent structured intermittent auscultation (ISIA) framework was developed. The purpose of this discussion paper is to describe the application of intelligent structured intermittent auscultation in practice. The intelligent structured intermittent auscultation decision-making framework is a knowledge translation tool that supports the implementation of evidence into practice around the use of intermittent auscultation for fetal heart monitoring for low-risk women during labour. An understanding of the physiology of the materno-utero-placental unit and control of the fetal heart underpin the development of the framework. Intelligent structured intermittent auscultation provides midwives with a robust means of demonstrating their critical thinking and clinical reasoning and supports their understanding of normal physiological birth. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance.

Science.gov (United States)

Baker, Lindsay B; Rollo, Ian; Stein, Kimberly W; Jeukendrup, Asker E

2015-07-14

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 and during a game

Study of pentoxifylline effects on motility and viability of spermatozoa from infertile asthenozoospermic males

OpenAIRE

Ghasemzadeh, Aliye; Karkon-Shayan, Farid; Yousefzadeh, Solmaz; Naghavi-Behzad, Mohammad; Hamdi, Kobra

2016-01-01

Background: The quality of semen is one of the major parameters in male infertility. Pentoxifylline, a methylxanthine derivative, is an agent primarily used in the treatment of intermittent claudication and other vascular disorders. Studies have shown that pentoxifylline enhances the quality and quantity of sperms. In this study, we have investigated the in vitro effects of pentoxifylline on viability and motility of spermatozoa in samples of infertile oligoasthenozoospermic males. Materials ...

Coherent Structures and Intermittency in Plasma Turbulence

International Nuclear Information System (INIS)

Das, Amita; Kaw, Predhiman; Sen, Abhijit

2008-01-01

The paper discusses some fundamental issues related to the phenomenon of intermittency in plasma turbulence with particular reference to experimental observations in fusion devices. Intermittency is typically associated with the presence of coherent structures in turbulence. Since coherent structures can play an important role in governing the transport properties of a system they have received a great deal of attention in fusion research. We review some of the experimental measurements and numerical simulation studies on the presence and formation of coherent structures in plasmas and discuss their relevance to intermittency. Intermittency, as widely discussed in the context of neutral fluid turbulence, implies multiscaling behaviour in contrast to self-similar scaling patterns observed in self organized criticality (SOC) phenomenon. The experimental evidence from plasma turbulence measurements reveal a mixed picture--while some observations support the SOC model description others indicate the presence of multiscaling behaviour. We discuss these results in the light of our present understanding of plasma turbulence and in terms of certain unique aspects of intermittency as revealed by fluid models of plasmas.

A neonatal mouse model of intermittent hypoxia associated with features of apnea in premature infants.

Science.gov (United States)

Cai, Jun; Tuong, Chi Minh; Gozal, David

2011-09-15

A neonatal mouse model of intermittent hypoxia (IH) simulating the recurring hypoxia/reoxygenation episodes of apnea of prematurity (AOP) was developed. C57BL/6 P2 pups were culled for exposure to either intermittent hypoxia or intermittent air as control. The IH paradigms consisted of alternation cycles of 20.9% O2 and either 8.0% or 5.7% O2 every 120 or 140s for 6h a day during daylight hours from day 2 to day 10 postnatally, i.e., roughly equivalent to human brain development in the perinatal period. IH exposures elicited modest to severe decrease in oxygen saturation along with bradycardia in neonatal mice, which were severity-dependent. Hypomyelination in both central and peripheral nervous systems was observed despite the absence of visible growth retardation. The neonatal mouse model of IH in this study partially fulfills the current diagnostic criteria with features of AOP, and provides opportunities to reproduce in rodents some of the pathophysiological changes associated with this disorder, such as alterations in myelination. Copyright © 2011 Elsevier B.V. All rights reserved.

Intermittent hypoxia increases insulin resistance in genetically obese mice.

Science.gov (United States)

Polotsky, Vsevolod Y; Li, Jianguo; Punjabi, Naresh M; Rubin, Arnon E; Smith, Philip L; Schwartz, Alan R; O'Donnell, Christopher P

2003-10-01

Obstructive sleep apnoea, a syndrome that leads to recurrent intermittent hypoxia, is associated with insulin resistance in obese individuals, but the mechanisms underlying this association remain unknown. We utilized a mouse model to examine the effects of intermittent hypoxia on insulin resistance in lean C57BL/6J mice and leptin-deficient obese (C57BL/6J-Lepob) mice. In lean mice, exposure to intermittent hypoxia for 5 days (short term) resulted in a decrease in fasting blood glucose levels (from 173 +/- 11 mg dl-1 on day 0 to 138 +/- 10 mg dl-1 on day 5, P obese mice, short-term intermittent hypoxia led to a decrease in blood glucose levels accompanied by a 607 +/- 136 % (P intermittent hypoxia was completely abolished by prior leptin infusion. Obese mice exposed to intermittent hypoxia for 12 weeks (long term) developed a time-dependent increase in fasting serum insulin levels (from 3.6 +/- 1.1 ng ml-1 at baseline to 9.8 +/- 1.8 ng ml-1 at week 12, P intermittent hypoxia is dependent on the disruption of leptin pathways.

The Yo-Yo intermittent recovery test

DEFF Research Database (Denmark)

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

2008-01-01

The two Yo-Yo intermittent recovery (IR) tests evaluate an individual's ability to repeatedly perform intense exercise. The Yo-Yo IR level 1 (Yo-Yo IR1) test focuses on the capacity to carry out intermittent exercise leading to a maximal activation of the aerobic system, whereas Yo-Yo IR level 2...

Dynamic characterizers of spatiotemporal intermittency

OpenAIRE

Gupte, Neelima; Jabeen, Zahera

2006-01-01

Systems of coupled sine circle maps show regimes of spatiotemporally intermittent behaviour with associated scaling exponents which belong to the DP class, as well as regimes of spatially intermittent behaviour (with associated regular dynamical behaviour) which do not belong to the DP class. Both types of behaviour are seen along the bifurcation boundaries of the synchronized solutions, and contribute distinct signatures to the dynamical characterizers of the system, viz. the distribution of...

Surgical treatment of chronic occlusive in peripheral arteries (Review of 100 cases

Directory of Open Access Journals (Sweden)

H. AHRARI

1977-01-01

Full Text Available The purpose of this article is to diseuse the philosophy of our approch to the severely ischemic extremity and ourcurrent methods of treatment. 1 - The natural history of artheriosclerotic arterial obstruction should always be borne in mind. There is no doubt that many people have some degree of arterial stenosis or obstrcction and never suffer symptoms, either because of the reduced demand due to senility or because they are prepared to tolerate minor inconveniences which do not significantly interfere with their lives or livelihood. It should also be remembered that a proportion of patients with claudication improve spontaneously ever a time scale extending to many months or years. Taylor and Cale (1962, in a long term follow up of patients with untreated intermittent claudication, found spontaneous relief of symptoms in 39 per cent of the cases, no change in 45% and 16% worsening. Because of this it is impossible to lay down precise rules concerning the treatment of patients with intermittent claudication. It would be wrong to advise major arterial surgery in an elderly patient with extensive main' vessel disease and relatively mild claudication, and equally wrong to deny surgical treatment to an active younger patient with a we 11 localized arterial lesion. It is superfuous to add that anyhow, the surgery must not make the patient worse. 2- In a survey of a decade of experience, the arterioplastie treatment of occlusive disease seems to fall int three groups based on the anatomic distribution of the lesion. (Ref, 13. A - These in whom the obstructive disease is limited to the aortoiliac segments of the arterial tree supplying the leg. B - Those with both aort-iliao and femoral arterial disease. C - These with only femoropopliteal or proximal part of the popliteal arteries. Results in both the aorto-iliac and femoral arterial disease operations were in general satisfactory. The good early results of aorto-iliac operations showed only a

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

Forces and energetics of intermittent swimming

Science.gov (United States)

Floryan, Daniel; Van Buren, Tyler; Smits, Alexander J.

2017-08-01

Experiments are reported on intermittent swimming motions. Water tunnel experiments on a nominally two-dimensional pitching foil show that the mean thrust and power scale linearly with the duty cycle, from a value of 0.2 all the way up to continuous motions, indicating that individual bursts of activity in intermittent motions are independent of each other. This conclusion is corroborated by particle image velocimetry (PIV) flow visualizations, which show that the main vortical structures in the wake do not change with duty cycle. The experimental data also demonstrate that intermittent motions are generally energetically advantageous over continuous motions. When metabolic energy losses are taken into account, this conclusion is maintained for metabolic power fractions less than 1.

Intermittent cranial lung herniation in two dogs.

Science.gov (United States)

Guglielmini, Carlo; De Simone, Antonio; Valbonetti, Luca; Diana, Alessia

2007-01-01

Two aged dogs with chronic obstructive airway disease were evaluated because of intermittent swelling of the ventral cervical region. Radiographs made at expiration and caudal positioning of the forelimbs allowed identification of intermittent cervical lung herniation of the left and right cranial lung lobe in both dogs. Pulmonary hyperinflation, increased expiratory effort, and chronic coughing were considered responsible for the lung herniation. Cervical lung hernia should be included in the differential diagnoses of intermittent cervical swelling in dogs with chronic respiratory disorders associated with increased expiratory effort and chronic coughing.

Intermittency in the particle production and in the nuclear multifragmentation

International Nuclear Information System (INIS)

Bozek, P.; Ploszajczak, M.

1991-01-01

Intermittency is a manifestation of scale invariance and randomness in physical systems. Intermittency in relativistic heavy-ion collisions and, in particular, the projectile dependence, multiplicity dependence and source-size dependence are discussed in the frame of the model of spatio-temporal intermittency. Moreover, recent theoretical results in intermittency studies of the nuclear multifragmentation are presented. (author) 35 refs., 4 figs., 1 tab

Intermittency and random matrices

Science.gov (United States)

Sokoloff, Dmitry; Illarionov, E. A.

2015-08-01

A spectacular phenomenon of intermittency, i.e. a progressive growth of higher statistical moments of a physical field excited by an instability in a random medium, attracted the attention of Zeldovich in the last years of his life. At that time, the mathematical aspects underlying the physical description of this phenomenon were still under development and relations between various findings in the field remained obscure. Contemporary results from the theory of the product of independent random matrices (the Furstenberg theory) allowed the elaboration of the phenomenon of intermittency in a systematic way. We consider applications of the Furstenberg theory to some problems in cosmology and dynamo theory.

Intermittent behavior of the logistic system

Science.gov (United States)

Mayer-Kress, G.; Haken, H.

1981-03-01

In the discrete logistic model a transition to chaotic behavior via intermittency occurs in a neighborhood of periodic bands. Intermittent behavior is also induced if a stable periodic orbit is perturbed by low-level external noise, whereas alterations due to computer digitalisation produce remarkable periodicities. We compare our numerical results with the predictions of Pomeau and Manneville for the Lorenz system.

Intermittent hydronephrosis

International Nuclear Information System (INIS)

Knop, J.; Vogel, H.; Hupe, W.

1981-01-01

An intermittent hydronephrosis was observed in a 40-year old patient. This disease pattern is due to an incongruity between the formation of urine and the transport capacity in the ureteropelvic junction. The latent impediment of flow becomes manifest with increased urine secretion. Irreversible renal damage can be the result of the repeatedly occurring hydronephrotic crises. (orig.) [de

Intermittency in Hall-magnetohydrodynamics with a strong guide field

OpenAIRE

Imazio, P. Rodriguez; Martin, L. N.; Dmitruk, P.; Mininni, P. D.

2013-01-01

We present a detailed study of intermittency in the velocity and magnetic field fluctuations of compressible Hall-magnetohydrodynamic turbulence with an external guide field. To solve the equations numerically, a reduced model valid when a strong guide field is present is used. Different values for the ion skin depth are considered in the simulations. The resulting data are analyzed computing field increments in several directions perpendicular to the guide field, and building structure funct...

Effect of intermittent treatment with amodiaquine on anaemia and malarial fevers in infants in Tanzania: a randomised placebo-controlled trial

DEFF Research Database (Denmark)

Massaga, Julius J; Kitua, Andrew Y; Lemnge, Martha M

2003-01-01

: Presumptive intermittent treatment for malaria with amodiaquine reduced malarial fevers and anaemia in infants, in an area with high resistance to other antimalarials. Intermittent treatment strategies for malaria in highly endemic areas could be of great benefit to public health.......BACKGROUND: Malaria is a major cause of infant morbidity and mortality in sub-Saharan Africa, and is often complicated by severe anaemia. Resistance of Plasmodium falciparum to most affordable antimalarial drugs is an impediment to intermittent chemotherapy. We investigated the effect...... of presumptive intermittent treatment with amodiaquine and daily iron supplementation in infants on malarial fevers and anaemia, in a holoendemic area of Tanzania where malaria is largely resistant to chloroquine and sulfadoxine/ pyrimethamine. METHODS: 291 infants aged 12-16 weeks who attended three clinics...

Characterization of intermittency in zooplankton behaviour in turbulence.

Science.gov (United States)

Michalec, François-Gaël; Schmitt, François G; Souissi, Sami; Holzner, Markus

2015-10-01

We consider Lagrangian velocity differences of zooplankters swimming in still water and in turbulence. Using cumulants, we quantify the intermittency properties of their motion recorded using three-dimensional particle tracking velocimetry. Copepods swimming in still water display an intermittent behaviour characterized by a high probability of small velocity increments, and by stretched exponential tails. Low values arise from their steady cruising behaviour while heavy tails result from frequent relocation jumps. In turbulence, we show that at short time scales, the intermittency signature of active copepods clearly differs from that of the underlying flow, and reflects the frequent relocation jumps displayed by these small animals. Despite these differences, we show that copepods swimming in still and turbulent flow belong to the same intermittency class that can be modelled by a log-stable model with non-analytical cumulant generating function. Intermittency in swimming behaviour and relocation jumps may enable copepods to display oriented, collective motion under strong hydrodynamic conditions and thus, may contribute to the formation of zooplankton patches in energetic environments.

Intermittent hypoxia impairs glucose homeostasis in C57BL6/J mice: partial improvement with cessation of the exposure.

Science.gov (United States)

Polak, Jan; Shimoda, Larissa A; Drager, Luciano F; Undem, Clark; McHugh, Holly; Polotsky, Vsevolod Y; Punjabi, Naresh M

2013-10-01

Obstructive sleep apnea is associated with insulin resistance, glucose intolerance, and type 2 diabetes mellitus. Although several studies have suggested that intermittent hypoxia in obstructive sleep apnea may induce abnormalities in glucose homeostasis, it remains to be determined whether these abnormalities improve after discontinuation of the exposure. The objective of this study was to delineate the effects of intermittent hypoxia on glucose homeostasis, beta cell function, and liver glucose metabolism and to investigate whether the impairments improve after the hypoxic exposure is discontinued. C57BL6/J mice were exposed to 14 days of intermittent hypoxia, 14 days of intermittent air, or 7 days of intermittent hypoxia followed by 7 days of intermittent air (recovery paradigm). Glucose and insulin tolerance tests were performed to estimate whole-body insulin sensitivity and calculate measures of beta cell function. Oxidative stress in pancreatic tissue and glucose output from isolated hepatocytes were also assessed. Intermittent hypoxia increased fasting glucose levels and worsened glucose tolerance by 67% and 27%, respectively. Furthermore, intermittent hypoxia exposure was associated with impairments in insulin sensitivity and beta cell function, an increase in liver glycogen, higher hepatocyte glucose output, and an increase in oxidative stress in the pancreas. While fasting glucose levels and hepatic glucose output normalized after discontinuation of the hypoxic exposure, glucose intolerance, insulin resistance, and impairments in beta cell function persisted. Intermittent hypoxia induces insulin resistance, impairs beta cell function, enhances hepatocyte glucose output, and increases oxidative stress in the pancreas. Cessation of the hypoxic exposure does not fully reverse the observed changes in glucose metabolism.

[A 65-year-old man with history of claudication, palpable purpura and livedo reticularis].

Science.gov (United States)

Braun, N; Kimmel, M; Grabner, A; Ott, G; Alscher, M D

2010-04-01

A 65-year-old man was admitted with history of claudication symptoms and painful skin lesions of the lower legs. Physical examination showed palpable purpura of the lower legs and livedo reticularis, most marked at the forefoot and toes. Computed tomography (CT) showed an aortic mass 2 cm above the bifurcation. This was treated after angiography with a covered stent. Biopsy of the skin lesions showed no sign of vasculitis and no cholesterol crystals. The patient was discharged and remained symptom-free for 9 months. He was readmitted at that time with recurrent complaints. CT revealed a subtotal stenosis of the aortic stent. A skin biopsy showed CD31-positive tumor cells in small arteries. Biopsy of a new osteolytic lesion in the ileum confirmed the diagnosis of angiosarcoma of the aorta. The patient decided in favor of palliative care and was discharged from the hospital. Primary tumors of the aorta, although they are rare, should be considered in the presence of an intravascular mass with stenosis to blood flow. A skin biopsy is easy to conduct and often leads to the final diagnosis. Georg Thieme Verlag KG Stuttgart. New York.

Unsteady propulsion by an intermittent swimming gait

Science.gov (United States)

Akoz, Emre; Moored, Keith W.

2018-01-01

Inviscid computational results are presented on a self-propelled swimmer modeled as a virtual body combined with a two-dimensional hydrofoil pitching intermittently about its leading edge. Lighthill (1971) originally proposed that this burst-and-coast behavior can save fish energy during swimming by taking advantage of the viscous Bone-Lighthill boundary layer thinning mechanism. Here, an additional inviscid Garrick mechanism is discovered that allows swimmers to control the ratio of their added mass thrust-producing forces to their circulatory drag-inducing forces by decreasing their duty cycle, DC, of locomotion. This mechanism can save intermittent swimmers as much as 60% of the energy it takes to swim continuously at the same speed. The inviscid energy savings are shown to increase with increasing amplitude of motion, increase with decreasing Lighthill number, Li, and switch to an energetic cost above continuous swimming for sufficiently low DC. Intermittent swimmers are observed to shed four vortices per cycle that form into groups that are self-similar with the DC. In addition, previous thrust and power scaling laws of continuous self-propelled swimming are further generalized to include intermittent swimming. The key is that by averaging the thrust and power coefficients over only the bursting period then the intermittent problem can be transformed into a continuous one. Furthermore, the intermittent thrust and power scaling relations are extended to predict the mean speed and cost of transport of swimmers. By tuning a few coefficients with a handful of simulations these self-propelled relations can become predictive. In the current study, the mean speed and cost of transport are predicted to within 3% and 18% of their full-scale values by using these relations.

To vigorously and safely develop the interventional therapy for diabetic peripheral vascular diseases

International Nuclear Information System (INIS)

Zhao Jungong; Cheng Yongde

2011-01-01

Diabetic critical limb ischemia is one of the most severe complications caused by diabetes mellitus, which carries significant morbidity and mortality. The symptoms related to limb ischemia include intermittent claudication, rest pain, refractory ulcers, infections or even gangrene of the foot or toes. Percutaneous transluminal angioplasty (PTA) can be used to treat arterial stenosis or occlusive disease of the iliac and femoropopliteal arteries. However, PTA has a relatively poor outcome for the treatment of infrapopliteal arteries with conventional short coronary balloons. In the past 10 years, infrapopliteal angioplasty with a long over-the-wire (OTW) balloon, subintimal technique, retrograde transdorsal-to-plantar loop, Excimer laser ablation, local delivery of paclitaxel, etc. have been continually developed. The clinical practise has proved that these techniques and devices are feasible and effective for the treatment of severe limb ischemia in diabetic patients. The midterm outcomes seem to be satisfactory and encouraging. (authors)

Stochastic synchronization of coupled neural networks with intermittent control

International Nuclear Information System (INIS)

Yang Xinsong; Cao Jinde

2009-01-01

In this Letter, we study the exponential stochastic synchronization problem for coupled neural networks with stochastic noise perturbations. Based on Lyapunov stability theory, inequality techniques, the properties of Weiner process, and adding different intermittent controllers, several sufficient conditions are obtained to ensure exponential stochastic synchronization of coupled neural networks with or without coupling delays under stochastic perturbations. These stochastic synchronization criteria are expressed in terms of several lower-dimensional linear matrix inequalities (LMIs) and can be easily verified. Moreover, the results of this Letter are applicable to both directed and undirected weighted networks. A numerical example and its simulations are offered to show the effectiveness of our new results.

Which factors make clean intermittent (self) catheterisation successful?

NARCIS (Netherlands)

Cobussen-Boekhorst, H.; Beekman, J.; Wijlick, E. van; Schaafstra, J.; Kuppevelt, D. van; Heesakkers, J.P.

2016-01-01

AIMS AND OBJECTIVES: To explore which factors determine successful intermittent catheterisation. BACKGROUND: Intermittent catheterisation is a safe, effective treatment and is associated with improved quality of life, although negative issues are reported. Factors which determine adherence are

Intermittent Hypoxia Impairs Glucose Homeostasis in C57BL6/J Mice: Partial Improvement with Cessation of the Exposure

Science.gov (United States)

Polak, Jan; Shimoda, Larissa A.; Drager, Luciano F.; Undem, Clark; McHugh, Holly; Polotsky, Vsevolod Y.; Punjabi, Naresh M.

2013-01-01

Objectives: Obstructive sleep apnea is associated with insulin resistance, glucose intolerance, and type 2 diabetes mellitus. Although several studies have suggested that intermittent hypoxia in obstructive sleep apnea may induce abnormalities in glucose homeostasis, it remains to be determined whether these abnormalities improve after discontinuation of the exposure. The objective of this study was to delineate the effects of intermittent hypoxia on glucose homeostasis, beta cell function, and liver glucose metabolism and to investigate whether the impairments improve after the hypoxic exposure is discontinued. Interventions: C57BL6/J mice were exposed to 14 days of intermittent hypoxia, 14 days of intermittent air, or 7 days of intermittent hypoxia followed by 7 days of intermittent air (recovery paradigm). Glucose and insulin tolerance tests were performed to estimate whole-body insulin sensitivity and calculate measures of beta cell function. Oxidative stress in pancreatic tissue and glucose output from isolated hepatocytes were also assessed. Results: Intermittent hypoxia increased fasting glucose levels and worsened glucose tolerance by 67% and 27%, respectively. Furthermore, intermittent hypoxia exposure was associated with impairments in insulin sensitivity and beta cell function, an increase in liver glycogen, higher hepatocyte glucose output, and an increase in oxidative stress in the pancreas. While fasting glucose levels and hepatic glucose output normalized after discontinuation of the hypoxic exposure, glucose intolerance, insulin resistance, and impairments in beta cell function persisted. Conclusions: Intermittent hypoxia induces insulin resistance, impairs beta cell function, enhances hepatocyte glucose output, and increases oxidative stress in the pancreas. Cessation of the hypoxic exposure does not fully reverse the observed changes in glucose metabolism. Citation: Polak J; Shimoda LA; Drager LF; Undem C; McHugh H; Polotsky VY; Punjabi NM

Childhood intermittent and persistent rhinitis prevalence and climate and vegetation: a global ecologic analysis.

Science.gov (United States)

Fuertes, Elaine; Butland, Barbara K; Ross Anderson, H; Carlsten, Chris; Strachan, David P; Brauer, Michael

2014-10-01

The effect of climate change and its effects on vegetation growth, and consequently on rhinitis, are uncertain. To examine between- and within-country associations of climate measures and the normalized difference vegetation index with intermittent and persistent rhinitis symptoms in a global context. Questionnaire data from 6- to 7-year-olds and 13- to 14-year-olds were collected in phase 3 of the International Study of Asthma and Allergies in Childhood. Associations of intermittent (>1 symptom report but not for 2 consecutive months) and persistent (symptoms for ≥2 consecutive months) rhinitis symptom prevalences with temperature, precipitation, vapor pressure, and the normalized difference vegetation index were assessed in linear mixed-effects regression models adjusted for gross national income and population density. The mean difference in prevalence per 100 children (with 95% confidence intervals [CIs]) per interquartile range increase of exposure is reported. The country-level intermittent symptom prevalence was associated with several country-level climatic measures, including the country-level mean monthly temperature (6.09 °C; 95% CI, 2.06-10.11°C per 10.4 °C), precipitation (3.10 mm; 95% CI, 0.46-5.73 mm; per 67.0 mm), and vapor pressure (6.21 hPa; 95% CI, 2.17-10.24 hPa; per 10.4 hPa) among 13- to 14-year-olds (222 center in 94 countries). The center-level persistent symptom prevalence was positively associated with several center-level climatic measures. Associations with climate were also found for the 6- to 7-year-olds (132 center in 57 countries). Several between- and within-country spatial associations between climatic factors and intermittent and persistent rhinitis symptom prevalences were observed. These results provide suggestive evidence that climate (and future changes in climate) may influence rhinitis symptom prevalence. Copyright © 2014 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Photonic integrated circuits unveil crisis-induced intermittency.

Science.gov (United States)

Karsaklian Dal Bosco, Andreas; Akizawa, Yasuhiro; Kanno, Kazutaka; Uchida, Atsushi; Harayama, Takahisa; Yoshimura, Kazuyuki

2016-09-19

We experimentally investigate an intermittent route to chaos in a photonic integrated circuit consisting of a semiconductor laser with time-delayed optical feedback from a short external cavity. The transition from a period-doubling dynamics to a fully-developed chaos reveals a stage intermittently exhibiting these two dynamics. We unveil the bifurcation mechanism underlying this route to chaos by using the Lang-Kobayashi model and demonstrate that the process is based on a phenomenon of attractor expansion initiated by a particular distribution of the local Lyapunov exponents. We emphasize on the crucial importance of the distribution of the steady-state solutions introduced by the time-delayed feedback on the existence of this intermittent dynamics.

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.

The effect of intermittent dosing of Nicotiana glauca on teratogenesis in goats.

Science.gov (United States)

Welch, K D; Panter, K E; Lee, S T; Gardner, D R

2015-01-01

Sustained inhibition of fetal movement in livestock species, induced by several poisonous plants, can result in numerous skeletal-contracture malformations. Lupines are responsible for a condition in cattle referred to as "crooked calf syndrome" that occurs when pregnant cattle graze teratogenic lupines. Similar malformations are also seen in animals poisoned by Conium maculatum (coniine) and Nicotiana glauca (anabasine). A proposed management strategy to limit these types of birth defects includes utilizing an intermittent grazing schedule to allow short durations of grazing lupine-infested areas interrupted by movement to a lupine-free pasture. The objective of this study was to use a goat model to determine if an intermittent schedule of five continuous days on treatment followed by two days off treatment would be sufficient to decrease, or prevent, the incidence of anabasine-induced malformations. The data from this study suggest that, for N. glauca in goats, the intermittent grazing program of five days exposure with two days of non-exposure is insufficient to prevent significant skeletal malformations from occurring. However, this study did demonstrate an inverse relationship between the amount of serum anabasine in the dam and the extent of fetal movement. Published by Elsevier Ltd.

Controls on streamflow intermittence in the Colorado Front Range

Science.gov (United States)

Kampf, S. K.; Puntenney, K.; Martin, C.; Weber, R.; Gerlich, J.; Hammond, J. C.; Lefsky, M. A.

2017-12-01

Intermittent streams comprise more than 60% of the channel length in semiarid northern Colorado, yet little is known about their flow magnitude and timing. We used field surveys, stream sensors, and remote sensing to quantify spatial and temporal patterns of streamflow intermittence in the Cache la Poudre basin in 2016-2017. To evaluate potential controls on streamflow intermittence, we delineated the drainage area to each monitored point and quantified the catchment's mean precipitation, temperature, snow persistence, slope, aspect, vegetation type, soil type, and bedrock geology. During the period of study, most streams below 2500 m elevation and drainage areas >1 km2 had perennial flow, whereas nearly all streams with drainage areas <1 km2 had intermittent flow. For the high elevation intermittent streams, stream locations often differed substantially from the locations mapped in standard GIS data products. Initial analyses have identified no clearly quantifiable controls on flow duration of high elevation streams, but field observations indicate subsurface flow paths are important contributors to surface streams.

Intermittent oral iron supplementation during pregnancy (Review)

Science.gov (United States)

Peña-Rosas, Juan Pablo; De-Regil, Luz Maria; Dowswell, Therese; Viteri, Fernando E

2014-01-01

and most had high levels of attrition. Overall, there was no clear evidence of differences between groups for infant primary outcomes: low birthweight (average risk ratio (RR) 0.96; 95% confidence interval (CI) 0.61 to 1.52, seven studies), infant birthweight (mean difference MD −8.62 g; 95% CI −52.76 g to 35.52 g, eight studies), premature birth (average RR 1.82; 95% CI 0.75 to 4.40, four studies). None of the studies reported neonatal deaths or congenital anomalies. For maternal outcomes, there was no clear evidence of differences between groups for anaemia at term (average RR 1.22; 95% CI 0.84 to 1.80, four studies) and women receiving intermittent supplementation had less side effects (average RR 0.56; 95% CI 0.37 to 0.84, 11 studies) than those receiving daily supplements. Women receiving intermittent supplements were also at lower risk of having high haemoglobin (Hb) concentrations (greater than 130 g/L) during the second or third trimester of pregnancy (average RR 0.48; 95% CI 0.35 to 0.67, 13 studies). There were no significant differences in iron-deficiency anaemia between women receiving intermittent or daily iron+folic acid supplementation (average RR 0.71; 95% CI 0.08 to 6.63, 1 study). There were no maternal deaths (six studies) or women with severe anaemia in pregnancy (six studies). None of the studies reported on iron deficiency at term or infections during pregnancy. Where sufficient data were available for primary outcomes, we set up subgroups to look for possible differences between studies in terms of earlier or later supplementation; women’s anaemia status at the start of supplementation; higher and lower weekly doses of iron; and the malarial status of the region in which the trials were conducted. There was no clear effect of these variables on the results of the review. Authors’ conclusions The present systematic review is the most comprehensive summary of the evidence assessing the benefits and harms of intermittent iron

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)

Intermittent versus continuous exercise training in chronic heart failure: a meta-analysis.

Science.gov (United States)

Smart, Neil A; Dieberg, Gudrun; Giallauria, Francesco

2013-06-20

We conducted a meta-analysis of randomized, controlled trials of combined strength and intermittent aerobic training, intermittent aerobic training only and continuous exercise training in heart failure patients. A systematic search was conducted of Medline (Ovid) (1950-September 2011), Embase.com (1974-September 2011), Cochrane Central Register of Controlled Trials and CINAHL (1981-September 19 2011). The search strategy included a mix of MeSH and free text terms for the key concepts heart failure, exercise training, interval training and intermittent exercise training. The included studies contained an aggregate of 446 patients, 212 completed intermittent exercise training, 66 only continuous exercise training, 59 completed combined intermittent and strength training and 109 sedentary controls. Weighted mean difference (MD) in Peak VO2 was 1.04mlkg(-1)min(-1) and (95% C.I.) was 0.42-1.66 (p=0.0009) in intermittent versus continuous exercise training respectively. Weighted mean difference in Peak VO2 was -1.10mlkg(-1)min(-1) (95% C.I.) was -1.83-0.37 p=0.003 for intermittent only versus intermittent and strength (combined) training respectively. In studies reporting VE/VCO2 for intermittent versus control groups, MD was -1.50 [(95% C.I. -2.64, -0.37), p=0.01] and for intermittent versus continuous exercise training MD was -1.35 [(95% C.I. -2.15, -0.55), p=0.001]. Change in peak VO2 was positively correlated with weekly exercise energy expenditure for intermittent exercise groups (r=0.48, p=0.05). Combined strength and intermittent exercise appears superior for peak VO2 changes when compared to intermittent exercise of similar exercise energy expenditure. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Under X-ray guidance stent implantation through retrograde popliteal artery puncturing for the treatment of superficial femoral artery occlusion: the initial results in nine cases

International Nuclear Information System (INIS)

He Xu; Gu Jianping; Lou Wensheng; Chen Liang; Chen Guoping; Su Haobo; Song Jinhua; Wang Tao; Xu Ke

2011-01-01

Objective: To discuss the application of retrograde popliteal artery puncturing under X-ray guidance in the interventional therapy for superficial femoral artery occlusion. Methods: Retrograde popliteal artery puncturing under X-ray guidance was carried out in nine patients with long-segment occlusion of superficial femoral artery as antegrade recanalization via femoral artery approach had failed in them. After retrograde route was successfully established, the balloon dilation and subsequent stent placement for occluded vessel were performed. Results: The technical success was obtained in all patients. The occluded superficial femoral arteries were reopened and the symptoms of intermittent claudication disappeared. No serious complications such as injuries of adjacent nerves or vessels occurred. The ankle-brachial index (ABI) increased from preoperative (0.38±0.13) to postoperative (0.92±0.11) with the difference being statistically significant (P<0.01). A follow-up period lasting for 2-16 months was conducted. Eleven months after the treatment, intermittent claudication recurred in one case, and CT angiography showed that the distal part of the stent was narrowed. The symptoms were improved after percutaneous transcatheter angioplasty was performed again. Conclusion: Retrograde popliteal artery puncturing under X-ray guidance is an effective and safe technique for the treatment of superficial femoral artery long-segment occlusion with stent placement, especially for patients in whom antegrade recanalization via femoral artery approach fails. (authors)

Subintimal angioplasty for the treatment of long segment occlusion of superficial femoral artery: the midterm results

International Nuclear Information System (INIS)

Lou Wensheng; Gu Jianping; He Xu; Chen Liang; Chen Guoping; Su Haobo; Song Jinhua; Wang Tao; Xu Ke

2011-01-01

Objective: To discuss the clinical value of subintimal angioplasty in treating long segment occlusion of superficial femoral artery and to observe its midterm results. Methods: Subintimal angioplasty was performed in 45 patients with long segment occlusion of superficial femoral artery, whose clinical presentation was intermittent claudication or critical limb ischemia. The primary patency, limb salvage and factors influencing long-term patency were observed, and the clinical data were analyzed. Results: Of the total 45 cases, the subintimal angioplasty was successfully accomplished in 43. The success rate of antegrade approach technique via the superficial femoral artery was 80% (n=36), the occlusion was recanalized by using retrograde approach technique via ipsilateral popliteal artery in 7 case. The total technical success rate was 95.6%. The primary patency in 43 successful cases at 6, 12, 24 and 36 months was 85.7%, 69.0% 57.3% and 50.9%, respectively. No statistically significant difference in primary patency existed between the group of intermittent claudication and the group of critical limb ischemia (P>0.05). Statistically significant prediction factors for primary patency included the number of the run off vessels below the knee and the length of the occlusion (P<0.05). Conclusion: Subintimal angioplasty is an effective procedure for the treatment of long segment occlusions of superficial femoral artery with satisfactory mid-term results. (authors)

Impact of age on intermittent hypoxia in obstructive sleep apnea: a propensity-matched analysis.

Science.gov (United States)

Bostanci, Asli; Bozkurt, Selen; Turhan, Murat

2018-05-01

To determine independent relationship of aging with chronic intermittent hypoxia, we compared hypoxia-related polysomnographic variables of geriatric patients (aged ≥ 65 years) with an apnea-hypopnea index (AHI)-, gender-, body mass index (BMI)-, and neck circumference-matched cohort of non-geriatric patients. The study was conducted using clinical and polysomnographic data of 1280 consecutive patients who underwent complete polysomnographic evaluation for suspected sleep-disordered breathing (SDB) at a single sleep disorder center. A propensity score-matched analysis was performed to obtain matched cohorts of geriatric and non-geriatric patients, which resulted in successful matching of 168 patients from each group. Study groups were comparable for gender (P = 0.999), BMI (P = 0.940), neck circumference (P = 0.969), AHI (P = 0.935), and severity of SDB (P = 0.089). The oximetric variables representing the duration of chronic intermittent hypoxia such as mean (P = 0.001), the longest (P = 0.001) and total apnea durations (P = 0.003), mean (P = 0.001) and the longest hypopnea durations (P = 0.001), and total sleep time with oxygen saturation below 90% (P = 0.008) were significantly higher in the geriatric patients as compared with younger adults. Geriatric patients had significantly lower minimum (P = 0.013) and mean oxygen saturation (P = 0.001) than non-geriatric patients. The study provides evidence that elderly patients exhibit more severe and deeper nocturnal intermittent hypoxia than the younger adults, independent of severity of obstructive sleep apnea, BMI, gender, and neck circumference. Hypoxia-related polysomnographic variables in geriatric patients may in fact reflect a physiological aging process rather than the severity of a SDB.

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.

Impact of repeated daily exposure to intermittent hypoxia and mild sustained hypercapnia on apnea severity.

Science.gov (United States)

Yokhana, Sanar S; Gerst, David G; Lee, Dorothy S; Badr, M Safwan; Qureshi, Tabarak; Mateika, Jason H

2012-02-01

We examined whether exposure to intermittent hypoxia (IH) during wakefulness impacted on the apnea/hypopnea index (AHI) during sleep in individuals with sleep apnea. Participants were exposed to twelve 4-min episodes of hypoxia in the presence of sustained mild hypercapnia each day for 10 days. A control group was exposed to sustained mild hypercapnia for a similar duration. The intermittent hypoxia protocol was completed in the evening on day 1 and 10 and was followed by a sleep study. During all sleep studies, the change in esophageal pressure (ΔPes) from the beginning to the end of an apnea and the tidal volume immediately following apneic events were used to measure respiratory drive. Following exposure to IH on day 1 and 10, the AHI increased above baseline measures (day 1: 1.95 ± 0.42 fraction of baseline, P ≤ 0.01, vs. day 10: 1.53 ± 0.24 fraction of baseline, P < 0.06). The indexes were correlated to the hypoxic ventilatory response (HVR) measured during the IH protocol but were not correlated to the magnitude of ventilatory long-term facilitation (vLTF). Likewise, ΔPes and tidal volume measures were greater on day 1 and 10 compared with baseline (ΔPes: -8.37 ± 0.84 vs. -5.90 ± 1.30 cmH(2)0, P ≤ 0.04; tidal volume: 1,193.36 ± 101.85 vs. 1,015.14 ± 119.83 ml, P ≤ 0.01). This was not the case in the control group. Interestingly, the AHI on day 10 (0.78 ± 0.13 fraction of baseline, P ≤ 0.01) was significantly less than measures obtained during baseline and day 1 in the mild hypercapnia control group. We conclude that enhancement of the HVR initiated by exposure to IH may lead to increases in the AHI during sleep and that initiation of vLTF did not appear to impact on breathing stability. Lastly, our results suggest that repeated daily exposure to mild sustained hypercapnia may lead to a decrease in breathing events.

Small-world networks exhibit pronounced intermittent synchronization

Science.gov (United States)

Choudhary, Anshul; Mitra, Chiranjit; Kohar, Vivek; Sinha, Sudeshna; Kurths, Jürgen

2017-11-01

We report the phenomenon of temporally intermittently synchronized and desynchronized dynamics in Watts-Strogatz networks of chaotic Rössler oscillators. We consider topologies for which the master stability function (MSF) predicts stable synchronized behaviour, as the rewiring probability (p) is tuned from 0 to 1. MSF essentially utilizes the largest non-zero Lyapunov exponent transversal to the synchronization manifold in making stability considerations, thereby ignoring the other Lyapunov exponents. However, for an N-node networked dynamical system, we observe that the difference in its Lyapunov spectra (corresponding to the N - 1 directions transversal to the synchronization manifold) is crucial and serves as an indicator of the presence of intermittently synchronized behaviour. In addition to the linear stability-based (MSF) analysis, we further provide global stability estimate in terms of the fraction of state-space volume shared by the intermittently synchronized state, as p is varied from 0 to 1. This fraction becomes appreciably large in the small-world regime, which is surprising, since this limit has been otherwise considered optimal for synchronized dynamics. Finally, we characterize the nature of the observed intermittency and its dominance in state-space as network rewiring probability (p) is varied.

A botanical compound, Padma 28, increases walking distance in stable intermittent claudication

DEFF Research Database (Denmark)

Drabaek, H; Mehlsen, J; Himmelstrup, H

1993-01-01

and by measurements of the pain-free and the maximal walking distance on a treadmill. The ankle pressure index (ankle systolic pressure/arm systolic pressure) was calculated. The group randomized to active treatment received two tablets bid containing 340 mg of a dried herbal mixture composed according to an ancient...

Intermittent Testicular Torsion

African Journals Online (AJOL)

2017-06-02

Jun 2, 2017 ... had prior episodes of testicular pain, suggesting that they may have had intermittent torsion before .... None of the patients had antecedent history of sexual exposure, fever, or urinary tract infection .... torsion of the spermatic cord portends an increased risk of acute testicular infarction. J Urol 2008;180 4 ...

Effect of Intermittent Hypercapnia on Respiratory Control in Rat Pups

Science.gov (United States)

Steggerda, Justin A.; Mayer, Catherine A.; Martin, Richard J.; Wilson, Christopher G.

2010-01-01

Preterm infants are subject to fluctuations in blood gas status associated with immature respiratory control. Intermittent hypoxia during early postnatal life has been shown to increase chemoreceptor sensitivity and destabilize the breathing pattern; however, intermittent hypercapnia remains poorly studied. Therefore, to test the hypothesis that intermittent hypercapnia results in altered respiratory control, we examined the effects of daily exposure to intermittent hypercapnia on the ventilatory response to subsequent hypercapnic and hypoxic exposure in neonatal rat pups. Exposure cycles consisted of 5 min of intermittent hypercapnia (5% CO2, 21% O2, balance N2) followed by 10 min of normoxia. Rat pups were exposed to 18 exposure cycles each day for 1 week, from postnatal day 7 to 14. We analyzed diaphragm electromyograms (EMGs) from pups exposed to subsequent acute hypercapnic (5% CO2) and hypoxic (12% O2) challenges. In response to a subsequent hypercapnia challenge, there was no significant difference in the ventilatory response between control and intermittent hypercapnia-exposed groups. In contrast, intermittent hypercapnia-exposed rat pups showed an enhanced ventilatory response to hypoxic challenge with an increase in minute EMG to 118 ± 14% of baseline versus 107 ± 13% for control pups (p < 0.05). We speculate that prior hypercapnic exposure may increase peripheral chemoreceptor response to subsequent hypoxic exposures and result in perturbed neonatal respiratory control. PMID:19752577

Degrees-of-Freedom of the MIMO Three-Way Channel with Node-Intermittency

KAUST Repository

Neu, Joachim

2017-08-28

The characterization of fundamental performance bounds of many-to-many communication systems in which participating nodes are active in an intermittent way is one of the major challenges in communication theory. In order to address this issue, we introduce the multiple-input multiple-output (MIMO) three-way channel (3WC) with an intermittent node and study its degrees-of-freedom (DoF) region and sum-DoF. We devise a non-adaptive encoding scheme based on zero-forcing, interference alignment and erasure coding, and show its DoF region (and thus sum-DoF) optimality for non-intermittent 3WCs and its sum-DoF optimality for (node-)intermittent 3WCs. However, we show by example that in general some DoF tuples in the intermittent 3WC can only be achieved by adaptive schemes, such as multi-hop or decode-forward relaying. This shows that non-adaptive encoding is sufficient for the non-intermittent 3WC and for the sum-DoF of intermittent 3WCs, but adaptive encoding is necessary for the DoF region of intermittent 3WCs. Our work contributes to a better understanding of the fundamental limits of multi-way communication systems with intermittency and the impact of adaptation therein.

Intermittent fasting: a "new" historical strategy for controlling seizures?

Science.gov (United States)

Hartman, Adam L; Rubenstein, James E; Kossoff, Eric H

2013-05-01

In antiquity, fasting was a treatment for epilepsy and a rationale for the ketogenic diet (KD). Preclinical data indicate the KD and intermittent fasting do not share identical anticonvulsant mechanisms. We implemented an intermittent fasting regimen in six children with an incomplete response to a KD. Three patients adhered to the combined intermittent fasting/KD regimen for 2 months and four had transient improvement in seizure control, albeit with some hunger-related adverse reactions. Copyright © 2012 Elsevier B.V. All rights reserved.

[Treatment for patients who have arterial ulcers].

Science.gov (United States)

Antolínez de Abia, Noelia

2009-01-01

Arterial ulcers are produced due to chronic ischemia in lower limbs. This causes a progressive, slow decrease in blood flow and oxygen supply to lower limbs. The main symptom consists of an intermittent claudication, or muscle pain while walking which ceases upon resting, but, when these symptoms appear; this wound usually is advanced and medical professionals basically use surgical, pharmaceutical and local treatments to cure this ulcer. In this article, the author presents a guide to diagnosis, treatment and prevention of arterial ulcers.

Hierarchy compensation of non-homogeneous intermittent atmospheric turbulence

Science.gov (United States)

Redondo, Jose M.; Mahjoub, Otman B.; Cantalapiedra, Inma R.

2010-05-01

In this work a study both the internal turbulence energy cascade intermittency evaluated from wind speed series in the atmospheric boundary layer, as well as the role of external or forcing intermittency based on the flatness (Vindel et al 2008)is carried out. The degree of intermittency in the stratified ABL flow (Cuxart et al. 2000) can be studied as the deviation, from the linear form, of the absolute scaling exponents of the structure functions as well as generalizing for non-isotropic and non-homogeneous turbulence, even in non-inertial ranges (in the Kolmogorov-Kraichnan sense) where the scaling exponents are not constant. The degree of intermittency, evaluated in the non-local quasi-inertial range, is explained from the variation with scale of the energy transfer as well as the dissipation. The scale to scale transfer and the structure function scaling exponents are calculated and from these the intermittency parametres. The turbulent diffusivity could also be estimated and compared with Richardson's law. Some two point correlations and time lag calculations are used to investigate the time and spatial integral length scales obtained from both Lagrangian and Eulerian correlations and functions, and we compare these results with both theoretical and laboratory data. We develop a theoretical description of how to measure the different levels of intermittency following (Mahjoub et al. 1998, 2000) and the role of locality in higher order exponents of structure function analysis. Vindel J.M., Yague C. and Redondo J.M. (2008) Structure function analysis and intermittency in the ABL. Nonlin. Processes Geophys., 15, 915-929. Cuxart J, Yague C, Morales G, Terradellas E, Orbe J, Calvo J, Fernández A, Soler M R, Infante C, Buenestado P, Espinalt A, Joergensen H E, Rees J M, Vilá J, Redondo J M, Cantalapiedra R and Conangla L (2000): Stable atmospheric boundary-layer experiment in Spain (Sables 98): a report, Boundary-Layer Meteorology 96, 337-370 Mahjoub O

Intermittent fasting and cardiovascular disease: current evidence and unresolved questions.

Science.gov (United States)

Tinsley, Grant M; Horne, Benjamin D

2018-01-01

Intermittent fasting has produced a variety of beneficial health effects in animal models, although high-quality research in humans has been limited. This special report examines current evidences for intermittent fasting in humans, discusses issues that require further examination, and recommends new research that can improve the knowledge base in this emerging research area. While potentially useful for health improvement, intermittent fasting requires further study prior to widespread implementation for health purposes. Randomized, longer-term studies are needed to determine whether using intermittent fasting as a lifestyle rather than a diet is feasible and beneficial for the health of some members of the human population.

Mechanisms of Sympathetic Activation and Blood Pressure Elevation by Intermittent Hypoxia

OpenAIRE

Prabhakar, Nanduri R.; Kumar, Ganesh K.

2010-01-01

Sleep disordered breathing with recurrent apneas is one of the most frequently encountered breathing disorder in adult humans and preterm infants. Recurrent apnea patients exhibit several co-morbidities including hypertension and persistent sympathetic activation. Intermittent hypoxia (IH) resulting from apneas appears to be the primary stimulus for evoking autonomic changes. The purpose of this article is to briefly review the effects of IH on chemo-and baro-reflexes and circulating vasoacti...

Assessment of the quality of life of patients with peripheral vascular diseases

International Nuclear Information System (INIS)

Wohlgemuth, W.A.; Bayreuth Univ.; Niechzial, M.; Nagel, E.; Bohndorf, K.

2003-01-01

The Medical Outcome Short Form 36 is commonly used as a generic quality of life measure in the assessment of vascular disease. The Claudication Scale CLAU-S, the PAVK-86 Fragebogen, and the Walking Impairment Questionnaire WIQ are validated disease-specific questionnaires for intermittent claudication. A disease specific tool for critical ischaemia is lacking. Quality of life of patients with peripheral arterial occlusive disease is not only impaired in the physical functioning domains (mobility, self care, activities of daily living), but moreover in their social and emotional wellbeing. This situation worsens under conservative treatment. Angioplasty and operation procedure similar improvements in all dimensions of hrQOL. As radiological interventional procedures just aim to improve hrQOL and do not bring a definite cure for the underlying disease, patients perception of their quality of life should be taken into account both in the indication for angioplasty and for the scientific evaluation of new treatment modalities. (orig.) [de

Complex economic dynamics: Chaotic saddle, crisis and intermittency

International Nuclear Information System (INIS)

Chian, Abraham C.-L.; Rempel, Erico L.; Rogers, Colin

2006-01-01

Complex economic dynamics is studied by a forced oscillator model of business cycles. The technique of numerical modeling is applied to characterize the fundamental properties of complex economic systems which exhibit multiscale and multistability behaviors, as well as coexistence of order and chaos. In particular, we focus on the dynamics and structure of unstable periodic orbits and chaotic saddles within a periodic window of the bifurcation diagram, at the onset of a saddle-node bifurcation and of an attractor merging crisis, and in the chaotic regions associated with type-I intermittency and crisis-induced intermittency, in non-linear economic cycles. Inside a periodic window, chaotic saddles are responsible for the transient motion preceding convergence to a periodic or a chaotic attractor. The links between chaotic saddles, crisis and intermittency in complex economic dynamics are discussed. We show that a chaotic attractor is composed of chaotic saddles and unstable periodic orbits located in the gap regions of chaotic saddles. Non-linear modeling of economic chaotic saddle, crisis and intermittency can improve our understanding of the dynamics of financial intermittency observed in stock market and foreign exchange market. Characterization of the complex dynamics of economic systems is a powerful tool for pattern recognition and forecasting of business and financial cycles, as well as for optimization of management strategy and decision technology

Effects of Intermittent Fasting on Experimental Autoimune Encephalomyelitis in C57BL/6 Mice.

Science.gov (United States)

Razeghi Jahromi, Soodeh; Ghaemi, Amir; Alizadeh, Akram; Sabetghadam, Fatemeh; Moradi Tabriz, Hedieh; Togha, Mansoureh

2016-06-01

Several religions recommend periods of fasting. One of the most frequently asked questions of MS patients before the holy month of Ramadan is weather fasting might have an unfavorable effect on their disease course. This debate became more challenging after the publication of experimental studies suggesting that calorie restriction prior to disease induction attenuates disease severity. We conducted this study to assess early and late effects of fasting on the animal model of MS, known as autoimmune encephalomyelitis. EAE was induced in the C57BL/6 mice, using Myelin Oligodendrocyte Glycopeptide  (MOG) 35-55 and they fasted every other day either after the appearance of the first clinical sign or 30 days after disease induction for ten days. Thereafter, the mice were sacrificed for further histological and immunological evaluations. Intermittent fasting after the establishment of EAE did not have any unfavorable effect on the course of disease. Moreover, fasting at the early phase of disease alleviated EAE severity by ameliorating spinal cord demyelination. Fasting suppressed the secretion of IFN-γ, TNF-α and raised IL-10 production in splenocytes. Fasting was also associated with a lower percent of cytotoxicity. Intermittent fasting not only had no unfavorable effect on EAE but also reduced EAE severity if started at early phase of disease.

Intermittent or daily montelukast versus placebo for episodic asthma in children.

Science.gov (United States)

Valovirta, Erkka; Boza, Maria L; Robertson, Colin F; Verbruggen, Nadia; Smugar, Steven S; Nelsen, Linda M; Knorr, Barbara A; Reiss, Theodore F; Philip, George; Gurner, Deborah M

2011-06-01

No standard, optimal treatment exists for severe intermittent (ie, episodic) asthma in children. However, evidence suggests that both daily and episode-driven montelukast are effective for this phenotype. To assess the regimen-related efficacy of montelukast in treating pediatric episodic asthma. A multicenter, randomized, double-blind, double-dummy, parallel-group, 52-week study was performed in children 6 months to 5 years of age comparing placebo with two regimens of montelukast 4 mg: (1) daily; or (2) episode-driven for 12 days beginning with signs/symptoms consistent with imminent cold or breathing problem. The main outcome measure was the number of asthma episodes (symptoms requiring treatment) culminating in an asthma attack (symptoms requiring physician visit, emergency room visit, corticosteroids, or hospitalization). Five hundred eighty-nine patients were randomized to daily montelukast, 591 to intermittent montelukast, and 591 to placebo. Compared with placebo, no significant difference was seen between daily montelukast (P = .510) or intermittent montelukast (P = .884) in the number of asthma episodes culminating in an asthma attack over 1 year. Daily montelukast reduced symptoms over the 12-day treatment period of asthma episodes compared with placebo (P = .045). Beta-agonist use was reduced with both daily (P = .048) and intermittent montelukast (P = .028) compared with placebo. However, because of prespecified rules for multiplicity adjustments (requiring a positive primary endpoint), statistical significance for secondary endpoints cannot be concluded. All treatments were well tolerated. Montelukast did not reduce the number of asthma episodes culminating in an asthma attack over 1 year in children 6 months to 5 years of age, although numerical improvements occurred in some endpoints. Copyright © 2011 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Intermittent intravenous followed by intermittent oral 1 alpha(OH)D3 treatment of secondary hyperparathyroidism in uraemia

DEFF Research Database (Denmark)

Brandi, L; Daugaard, H; Egsmose, C

1996-01-01

OBJECTIVES: To examine whether intermittent oral 1 alpha(OH)D3 treatment of patients on haemodialysis with secondary hyperparathyroidism (HPT) was able to maintain the marked suppression of PTH, which previously had been induced by an intermittent intravenous administration of 1 alpha(OH)D3....... Simultaneously, the effect of the different routes of administration of 1 alpha(OH)D3 on the circulating levels of N- and C-terminal PTH fragments was measured. DESIGN: An open study of patients on chronic haemodialysis. SETTING: Renal division, Rigshospitalet, Copenhagen, Denmark. SUBJECTS: A total of 26...

Subsurface Controls on Stream Intermittency in a Semi-Arid Landscape

Science.gov (United States)

Dohman, J.; Godsey, S.; Thackray, G. D.; Hale, R. L.; Wright, K.; Martinez, D.

2017-12-01

Intermittent streams currently constitute 30% to greater than 50% of the global river network. In addition, the number of intermittent streams is expected to increase due to changes in land use and climate. These streams provide important ecosystem services, such as water for irrigation, increased biodiversity, and high rates of nutrient cycling. Many hydrological studies have focused on mapping current intermittent flow regimes or evaluating long-term flow records, but very few have investigated the underlying causes of stream intermittency. The disconnection and reconnection of surface flow reflects the capacity of the subsurface to accommodate flow, so characterizing subsurface flow is key to understanding stream drying. We assess how subsurface flow paths control local surface flows during low-flow periods, including intermittency. Water table dynamics were monitored in an intermittent reach of Gibson Jack Creek in southeastern Idaho. Four transects were delineated with a groundwater well located in the hillslope, riparian zone, and in the stream, for a total of 12 groundwater wells. The presence or absence of surface flow was determined by frequent visual observations as well as in situ loggers every 30m along the 200m study reach. The rate of surface water drying was measured in conjunction with temperature, precipitation, subsurface hydraulic conductivity, hillslope-riparian-stream connectivity and subsurface travel time. Initial results during an unusually wet year suggest different responses in reaches that were previously observed to occasionally cease flowing. Flows in the intermittent reaches had less coherent and lower amplitude diel variations during base flow periods than reaches that had never been observed to dry out. Our findings will help contribute to our understanding of mechanisms driving expansion and contraction cycles in intermittent streams, increase our ability to predict how land use and climate change will affect flow regimes, and

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.)

Intermittent hyperthyreosis

International Nuclear Information System (INIS)

Sulman, F.G.; Tal, E.; Pfeifer, Y.; Superstine, E.

1975-01-01

Intermittent hyperthyreosis occurs under various forms of stress, especially heat stress. The clinician may diagnose such cases as masked or apathetic hyperthyroidism or 'forme fruste' hyperthyreosis or thyroid autonomy. As most routine and standard tests may here yield inconsistent results, it is the patients' anamnesis which may provide the clue. Our Bioclimatology Unit has now seen over 100 cases in which thyroid hypersensitivity towards heat was the most prominent syndrome: 10-15% of weather-sensitive patients are affected. The patients complain before or during heat spells of such contradictory symptoms as insomnia, irritability, tension, tachycardia, palpitations, precordial pain, dyspnoe, flushes with sweating or chills, tremor, abdominal pain or diarrhea, polyuria or pollakisuria, weight loss in spite of ravenous appetite, fatigue, exhaustion, depression, adynamia, lack of concentration and confusion. Determination of urinary neurohormones allows a differential diagnosis, intermittent hyperthyreosis being characterized by three cardinal symptoms: tachycardia - every case with more than 80 pulse beats being suspect (not specific); urinary histamine - every case excreting more than 90 μg/day being suspect. Again the drawback of this test is its lack of specificity, as histamine may also be increased in cases of allergy and spondylitis; urinary thyroxine - every case excreting more than 20 μg/day T-4 being suspect. This is the only specific test. Therapy should make use of lithium carbonate and betablockers. Propyl thiouracil is rarely required. (orig.) [de

Intermittency in Complex Flows

Science.gov (United States)

Ben Mahjoub, Otman; Redondo, Jose M.

2017-04-01

Experimental results of the complex turbulent wake of a cilinder in 2D [1] and 3D flows [2] were used to investigate the scaling of structure functions, similar research was also performed on wave propagation and breaking in the Ocean [3], in the the stratified Atmosphere (ABL) [4] and in a 100large flume (UPC) for both regular and irregular waves, where long time series of waves propagating and generating breaking turbulence velocity rms and higher order measurements were taken in depth. [3,5] by means of a velocimeter SONTEK3-D. The probability distribution functions of the velocity differences and their non Gaussian distribution related to the energy spectrum indicate that irregularity is an important source of turbulence. From Kolmogorov's K41 and K61 intermittency correction: the p th-order longitudinal velocity structure function δul at scale l in the inertial range of three-dimensional fully developed turbulence is related by ⟨δup⟩ = ⟨(u(x+ l)- u(x))p⟩ ˜ ɛp0/3lp/3 l where ⟨...⟩ represents the spatial average over flow domain, with ɛ0 the mean energy dissipation per unit mass and l is the separation distance. The importance of the random nature of the energy dissipation led to the K62 theory of intermittency, but locality and non-homogeneity are key issues. p p/3 p/3 ξd ⟨δul⟩ ˜ ⟨ɛl ⟩l ˜ l and ξp = p 3 + τp/3 , where now ɛl is a fractal energy dissipation at scale l, τp/3 is the scaling of and ξp is the scaling exponent of the velocity structure function of order p. Both in K41 and K62, the structure functions of third order related to skewness is ξ3 = 1. But this is not true either. We show that scaling exponents ξp do deviate from early studies that only investigated homogeneous turbulence, where a large inertial range dominates. The use of multi-fractal analysis and improvements on Structure function calculations on standard Enhanced mixing is an essential property of turbulence and efforts to alter and to control

Intermittent fasting: A “new” historical strategy for controlling seizures?

OpenAIRE

Hartman, Adam L.; Rubenstein, James E.; Kossoff, Eric H.

2012-01-01

In antiquity, fasting was a treatment for epilepsy and a rationale for the ketogenic diet (KD). Preclinical data indicate the KD and intermittent fasting do not share identical anticonvulsant mechanisms. We implemented an intermittent fasting regimen in six children with an incomplete response to a KD. Three patients adhered to the combined intermittent fasting/KD regimen for 2 months and four had transient improvement in seizure control, albeit with some hunger-related adverse reactions.

Sinusoidal visuomotor tracking: intermittent servo-control or coupled oscillations?

Science.gov (United States)

Russell, D M; Sternad, D

2001-12-01

In visuomotor tasks that involve accuracy demands, small directional changes in the trajectories have been taken as evidence of feedback-based error corrections. In the present study variability, or intermittency, in visuomanual tracking of sinusoidal targets was investigated. Two lines of analyses were pursued: First, the hypothesis that humans fundamentally act as intermittent servo-controllers was re-examined, probing the question of whether discontinuities in the movement trajectory directly imply intermittent control. Second, an alternative hypothesis was evaluated: that rhythmic tracking movements are generated by entrainment between the oscillations of the target and the actor, such that intermittency expresses the degree of stability. In 2 experiments, participants (N = 6 in each experiment) swung 1 of 2 different hand-held pendulums, tracking a rhythmic target that oscillated at different frequencies with a constant amplitude. In 1 line of analyses, the authors tested the intermittency hypothesis by using the typical kinematic error measures and spectral analysis. In a 2nd line, they examined relative phase and its variability, following analyses of rhythmic interlimb coordination. The results showed that visually guided corrective processes play a role, especially for slow movements. Intermittency, assessed as frequency and power components of the movement trajectory, was found to change as a function of both target frequency and the manipulandum's inertia. Support for entrainment was found in conditions in which task frequency was identical to or higher than the effector's eigenfrequency. The results suggest that it is the symmetry between task and effector that determines which behavioral regime is dominant.

Intermittent exposure to ethanol vapor affects osteoblast behaviour more severely than estrogen deficiency does

International Nuclear Information System (INIS)

Torricelli, Paola; Fini, Milena; Giavaresi, Gianluca; Borsari, Veronica; Rimondini, Lia; Rimondini, Roberto; Carrassi, Antonio; Giardino, Roberto

2007-01-01

With rising rates of alcohol consumption acute and chronic damage from alcohol is expected to increase all over the world. Habitual excessive alcohol consumption is associated with pathological effects on bone. The aim of the present in vitro study was to investigate comparatively the proliferation and synthetic activity of osteoblasts (OB) isolated from the trabecular bone of rats previously exposed to 7-week intermittent exposure to ethanol vapor, sham-aged rats and long-term estrogen deficient rats. Cell proliferation (WST1) and synthesis of alkaline phosphatase (ALP), osteocalcin (OC), collagen I (CICP), transforming growth factor beta1 (TGF-β1), interleukin-6 (IL-6), tumor necrosis factor alfa (TNFα) were measured at 3, 7 and 14 days of culture. Osteoblast proliferation rate and TGF-β1, IL-6 and TNFα syntheses were significantly affected by alcohol exposure. Estrogen deficiency and alcohol consumption share many common pathophysiological mechanisms of damage to bone, but alcohol affects OB proliferation and TNFα synthesis significantly more than menopause does. Therefore, these in vitro data suggest that alcohol has even more deleterious effects on bone than estrogen deficiency does

Intermittent fasting: A “new” historical strategy for controlling seizures?

Science.gov (United States)

Hartman, Adam L.; Rubenstein, James E.; Kossoff, Eric H.

2013-01-01

Summary In antiquity, fasting was a treatment for epilepsy and a rationale for the ketogenic diet (KD). Preclinical data indicate the KD and intermittent fasting do not share identical anticonvulsant mechanisms. We implemented an intermittent fasting regimen in six children with an incomplete response to a KD. Three patients adhered to the combined intermittent fasting/KD regimen for 2 months and four had transient improvement in seizure control, albeit with some hunger-related adverse reactions. PMID:23206889

Quantifying spatial and temporal patterns of flow intermittency using spatially contiguous runoff data

Science.gov (United States)

Yu (于松延), Songyan; Bond, Nick R.; Bunn, Stuart E.; Xu, Zongxue; Kennard, Mark J.

2018-04-01

River channel drying caused by intermittent stream flow is a widely-recognized factor shaping stream ecosystems. There is a strong need to quantify the distribution of intermittent streams across catchments to inform management. However, observational gauge networks provide only point estimates of streamflow variation. Increasingly, this limitation is being overcome through the use of spatially contiguous estimates of the terrestrial water-balance, which can also assist in estimating runoff and streamflow at large-spatial scales. Here we proposed an approach to quantifying spatial and temporal variation in monthly flow intermittency throughout river networks in eastern Australia. We aggregated gridded (5 × 5 km) monthly water-balance data with a hierarchically nested catchment dataset to simulate catchment runoff accumulation throughout river networks from 1900 to 2016. We also predicted zero flow duration for the entire river network by developing a robust predictive model relating measured zero flow duration (% months) to environmental predictor variables (based on 43 stream gauges). We then combined these datasets by using the predicted zero flow duration from the regression model to determine appropriate 'zero' flow thresholds for the modelled discharge data, which varied spatially across the catchments examined. Finally, based on modelled discharge data and identified actual zero flow thresholds, we derived summary metrics describing flow intermittency across the catchment (mean flow duration and coefficient-of-variation in flow permanence from 1900 to 2016). We also classified the relative degree of flow intermittency annually to characterise temporal variation in flow intermittency. Results showed that the degree of flow intermittency varied substantially across streams in eastern Australia, ranging from perennial streams flowing permanently (11-12 months) to strongly intermittent streams flowing 4 months or less of year. Results also showed that the

Major depressive disorder and depressive symptoms in intermittent explosive disorder.

Science.gov (United States)

Medeiros, Gustavo C; Seger, Liliana; Grant, Jon E; Tavares, Hermano

2018-04-01

It is estimated that between 1.7 and 2.6 million people have had intermittent explosive disorder (IED) during their life in the United States alone. Co-occurring psychiatric disorders are very common in IED, being major depressive disorder arguably the most common. The objective of this study was to examine the clinical correlates of IED and depressive manifestations in 74 treatment-seeking subjects. After controlling for confounders, there were associations between major depressive disorder and severity of depressive symptoms, and (a) higher assault scores, (b) more severe hostile behavior and (c) worse social adjustment. Management of depressive symptoms may be an important for IED treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

Randomized trial of intermittent or continuous amnioinfusion for variable decelerations.

Science.gov (United States)

Rinehart, B K; Terrone, D A; Barrow, J H; Isler, C M; Barrilleaux, P S; Roberts, W E

2000-10-01

To determine whether continuous or intermittent bolus amnioinfusion is more effective in relieving variable decelerations. Patients with repetitive variable decelerations were randomized to an intermittent bolus or continuous amnioinfusion. The intermittent bolus infusion group received boluses of 500 mL of normal saline, each over 30 minutes, with boluses repeated if variable decelerations recurred. The continuous infusion group received a bolus infusion of 500 mL of normal saline over 30 minutes and then 3 mL per minute until delivery occurred. The ability of the amnioinfusion to abolish variable decelerations was analyzed, as were maternal demographic and pregnancy outcome variables. Power analysis indicated that 64 patients would be required. Thirty-five patients were randomized to intermittent infusion and 30 to continuous infusion. There were no differences between groups in terms of maternal demographics, gestational age, delivery mode, neonatal outcome, median time to resolution of variable decelerations, or the number of times variable decelerations recurred. The median volume infused in the intermittent infusion group (500 mL) was significantly less than that in the continuous infusion group (905 mL, P =.003). Intermittent bolus amnioinfusion is as effective as continuous infusion in relieving variable decelerations in labor. Further investigation is necessary to determine whether either of these techniques is associated with increased occurrence of rare complications such as cord prolapse or uterine rupture.

Uncoupling of Vascular Nitric Oxide Synthase Caused by Intermittent Hypoxia

Directory of Open Access Journals (Sweden)

Mohammad Badran

2016-01-01

Full Text Available Objective. Obstructive sleep apnea (OSA, characterized by chronic intermittent hypoxia (CIH, is often present in diabetic (DB patients. Both conditions are associated with endothelial dysfunction and cardiovascular disease. We hypothesized that diabetic endothelial dysfunction is further compromised by CIH. Methods. Adult male diabetic (BKS.Cg-Dock7m +/+ Leprdb/J (db/db mice (10 weeks old and their heterozygote littermates were subjected to CIH or intermittent air (IA for 8 weeks. Mice were separated into 4 groups: IA (intermittent air nondiabetic, IH (intermittent hypoxia nondiabetic, IADB (intermittent air diabetic, and IHDB (intermittent hypoxia diabetic groups. Endothelium-dependent and endothelium-independent relaxation and modulation by basal nitric oxide (NO were analyzed using wire myograph. Plasma 8-isoprostane, interleukin-6 (IL-6, and asymmetric dimethylarginine (ADMA were measured using ELISA. Uncoupling of eNOS was measured using dihydroethidium (DHE staining. Results. Endothelium-dependent vasodilation and basal NO production were significantly impaired in the IH and IADB group compared to IA group but was more pronounced in IHDB group. Levels of 8-isoprostane, IL-6, ADMA, and eNOS uncoupling were ≈2-fold higher in IH and IADB groups and were further increased in the IHDB group. Conclusion. Endothelial dysfunction is more pronounced in diabetic mice subjected to CIH compared to diabetic or CIH mice alone. Oxidative stress, ADMA, and eNOS uncoupling were exacerbated by CIH in diabetic mice.

Accelerated anaerobic hydrolysis rates under a combination of intermittent aeration and anaerobic conditions

DEFF Research Database (Denmark)

Jensen, T. R.; Lastra Milone, T.; Petersen, G.

2017-01-01

Anaerobic hydrolysis in activated return sludge was investigated in laboratory scale experiments to find if intermittent aeration would accelerate anaerobic hydrolysis rates compared to anaerobic hydrolysis rates under strict anaerobic conditions. The intermittent reactors were set up in a 240 h...... for calculating hydrolysis rates based on soluble COD were compared. Two-way ANOVA with the Bonferroni post-test was performed in order to register any significant difference between reactors with intermittent aeration and strictly anaerobic conditions respectively. The experiment demonstrated a statistically...... significant difference in favor of the reactors with intermittent aeration showing a tendency towards accelerated anaerobic hydrolysis rates due to application of intermittent aeration. The conclusion of the work is thus that intermittent aeration applied in the activated return sludge process (ARP) can...

Intermittent pneumatic compression of legs increases microcirculation in distant skeletal muscle.

Science.gov (United States)

Liu, K; Chen, L E; Seaber, A V; Johnson, G W; Urbaniak, J R

1999-01-01

Intermittent pneumatic compression has been established as a method of clinically preventing deep vein thrombosis, but the mechanism has not been documented. This study observed the effects of intermittent pneumatic compression of legs on the microcirculation of distant skeletal muscle. The cremaster muscles of 80 male rats were exposed, a specially designed intermittent pneumatic-compression device was applied to both legs for 60 minutes, and the microcirculation of the muscles was assessed by measurement of the vessel diameter in three categories (10-20, 21-40, and 41-70 microm) for 120 minutes. The results showed significant vasodilation in arterial and venous vessels during the application of intermittent pneumatic compression, which disappeared after termination of the compression. The vasodilation reached a maximum 30 minutes after initiation of the compression and could be completely blocked by an inhibitor of nitric oxide synthase, NG-monomethyl-L-arginine (10 micromol/min). A 120-minute infusion of NG-monomethyl-L-arginine, beginning coincident with 60 minutes of intermittent pneumatic compression, resulted in a significant decrease in arterial diameter that remained at almost the same level after termination of the compression. The magnitude of the decrease in diameter in the group treated with intermittent pneumatic compression and NG-monomethyl-L-arginine was comparable with that in the group treated with NG-monomethyl-L-arginine alone. The results imply that the production of nitric oxide is involved in the positive influence of intermittent pneumatic compression on circulation. It is postulated that the rapid increase in venous velocity induced by intermittent pneumatic compression produces strong shear stress on the vascular endothelium, which stimulates an increased release of nitric oxide and thereby causes systemic vasodilation.

Intermittent synchronization in a network of bursting neurons

Science.gov (United States)

Park, Choongseok; Rubchinsky, Leonid L.

2011-09-01

Synchronized oscillations in networks of inhibitory and excitatory coupled bursting neurons are common in a variety of neural systems from central pattern generators to human brain circuits. One example of the latter is the subcortical network of the basal ganglia, formed by excitatory and inhibitory bursters of the subthalamic nucleus and globus pallidus, involved in motor control and affected in Parkinson's disease. Recent experiments have demonstrated the intermittent nature of the phase-locking of neural activity in this network. Here, we explore one potential mechanism to explain the intermittent phase-locking in a network. We simplify the network to obtain a model of two inhibitory coupled elements and explore its dynamics. We used geometric analysis and singular perturbation methods for dynamical systems to reduce the full model to a simpler set of equations. Mathematical analysis was completed using three slow variables with two different time scales. Intermittently, synchronous oscillations are generated by overlapped spiking which crucially depends on the geometry of the slow phase plane and the interplay between slow variables as well as the strength of synapses. Two slow variables are responsible for the generation of activity patterns with overlapped spiking, and the other slower variable enhances the robustness of an irregular and intermittent activity pattern. While the analyzed network and the explored mechanism of intermittent synchrony appear to be quite generic, the results of this analysis can be used to trace particular values of biophysical parameters (synaptic strength and parameters of calcium dynamics), which are known to be impacted in Parkinson's disease.

Synchronization of coupled stochastic complex-valued dynamical networks with time-varying delays via aperiodically intermittent adaptive control

Science.gov (United States)

Wang, Pengfei; Jin, Wei; Su, Huan

2018-04-01

This paper deals with the synchronization problem of a class of coupled stochastic complex-valued drive-response networks with time-varying delays via aperiodically intermittent adaptive control. Different from the previous works, the intermittent control is aperiodic and adaptive, and the restrictions on the control width and time delay are removed, which lead to a larger application scope for this control strategy. Then, based on the Lyapunov method and Kirchhoff's Matrix Tree Theorem as well as differential inequality techniques, several novel synchronization conditions are derived for the considered model. Specially, impulsive control is also considered, which can be seen as a special case of the aperiodically intermittent control when the control width tends to zero. And the corresponding synchronization criteria are given as well. As an application of the theoretical results, a class of stochastic complex-valued coupled oscillators with time-varying delays is studied, and the numerical simulations are also given to demonstrate the effectiveness of the control strategies.

Comparing microbial water quality in an intermittent and continuous piped water supply.

Science.gov (United States)

Kumpel, Emily; Nelson, Kara L

2013-09-15

Supplying piped water intermittently is a common practice throughout the world that increases the risk of microbial contamination through multiple mechanisms. Converting an intermittent supply to a continuous supply has the potential to improve the quality of water delivered to consumers. To understand the effects of this upgrade on water quality, we tested samples from reservoirs, consumer taps, and drinking water provided by households (e.g. from storage containers) from an intermittent and continuous supply in Hubli-Dharwad, India, over one year. Water samples were tested for total coliform, Escherichia coli, turbidity, free chlorine, and combined chlorine. While water quality was similar at service reservoirs supplying the continuous and intermittent sections of the network, indicator bacteria were detected more frequently and at higher concentrations in samples from taps supplied intermittently compared to those supplied continuously (p supply, with 0.7% of tap samples positive compared to 31.7% of intermittent water supply tap samples positive for E. coli. In samples from both continuously and intermittently supplied taps, higher concentrations of total coliform were measured after rainfall events. While source water quality declined slightly during the rainy season, only tap water from intermittent supply had significantly more indicator bacteria throughout the rainy season compared to the dry season. Drinking water samples provided by households in both continuous and intermittent supplies had higher concentrations of indicator bacteria than samples collected directly from taps. Most households with continuous supply continued to store water for drinking, resulting in re-contamination, which may reduce the benefits to water quality of converting to continuous supply. Copyright © 2013 Elsevier Ltd. All rights reserved.

Generation of intermittent gravitocapillary waves via parametric forcing

Science.gov (United States)

Castillo, Gustavo; Falcón, Claudio

2018-04-01

We report on the generation of an intermittent wave field driven by a horizontally moving wave maker interacting with Faraday waves. The spectrum of the local gravitocapillary surface wave fluctuations displays a power law in frequency for a wide range of forcing parameters. We compute the probability density function of the local surface height increments, which show that they change strongly across time scales. The structure functions of these increments are shown to display power laws as a function of the time lag, with exponents that are nonlinear functions of the order of the structure function. We argue that the origin of this scale-invariant intermittent spectrum is the Faraday wave pattern breakup due to its advection by the propagating gravity waves. Finally, some interpretations are proposed to explain the appearance of this intermittent spectrum.

Intermittency in e+e- and lepton-hadron collisions

International Nuclear Information System (INIS)

Sugano, K.

1990-01-01

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

Chronic Intermittent Hypoxia Induces Atherosclerosis

OpenAIRE

Savransky, Vladimir; Nanayakkara, Ashika; Li, Jianguo; Bevans, Shannon; Smith, Philip L.; Rodriguez, Annabelle; Polotsky, Vsevolod Y.

2007-01-01

Rationale: Obstructive sleep apnea, a condition leading to chronic intermittent hypoxia (CIH), is associated with hyperlipidemia, atherosclerosis, and a high cardiovascular risk. A causal link between obstructive sleep apnea and atherosclerosis has not been established.

Mammalian target of rapamycin is required for phrenic long-term facilitation following severe but not moderate acute intermittent hypoxia.

Science.gov (United States)

Dougherty, Brendan J; Fields, Daryl P; Mitchell, Gordon S

2015-09-01

Phrenic long-term facilitation (pLTF) is a persistent increase in phrenic nerve activity after acute intermittent hypoxia (AIH). Distinct cell-signaling cascades give rise to pLTF depending on the severity of hypoxemia within hypoxic episodes. Moderate AIH (mAIH; three 5-min episodes, PaO2 ∼35-55 mmHG) elicits pLTF by a serotonin (5-HT)-dependent mechanism that requires new synthesis of brain-derived neurotrophic factor (BDNF), activation of its high-affinity receptor (TrkB), and ERK MAPK signaling. In contrast, severe AIH (sAIH; three 5-min episodes, PaO2 ∼25-30 mmHG) elicits pLTF by an adenosine-dependent mechanism that requires new TrkB synthesis and Akt signaling. Although both mechanisms require spinal protein synthesis, the newly synthesized proteins are distinct, as are the neurochemicals inducing plasticity (serotonin vs. adenosine). In many forms of neuroplasticity, new protein synthesis requires translational regulation via mammalian target of rapamycin (mTOR) signaling. Since Akt regulates mTOR activity, we hypothesized that mTOR activity is necessary for sAIH- but not mAIH-induced pLTF. Phrenic nerve activity in anesthetized, paralyzed, and ventilated rats was recorded before, during, and 60 min after mAIH or sAIH. Rats were pretreated with intrathecal injections of 20% DMSO (vehicle controls) or rapamycin (0.1 mM, 12 μl), a selective mTOR complex 1 inhibitor. Consistent with our hypothesis, rapamycin blocked sAIH- but not mAIH-induced pLTF. Thus spinal mTOR activity is required for adenosine-dependent (sAIH) but not serotonin-dependent (mAIH) pLTF, suggesting that distinct mechanisms regulate new protein synthesis in these forms of spinal neuroplasticity. Copyright © 2015 the American Physiological Society.

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.

Intermittent Fasting Modulation of the Diabetic Syndrome in Streptozotocin-Injected Rats

OpenAIRE

Louiza Belkacemi; Ghalem Selselet-Attou; Emeline Hupkens; Evrard Nguidjoe; Karim Louchami; Abdullah Sener; Willy J. Malaisse

2012-01-01

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 benefic...

An intermittency route to global instability in low-density jets

Science.gov (United States)

Murugesan, Meenatchidevi; Zhu, Yuanhang; Li, Larry K. B.

2017-11-01

Above a critical Reynolds number (Re), a low-density jet can become globally unstable, transitioning from a steady state (i.e. a fixed point) to a self-excited oscillatory state (i.e. a limit cycle) via a Hopf bifurcation. In this experimental study, we show that this transition can sometimes involve intermittency. When Re is just slightly above the critical point, intermittent bursts of high-amplitude periodic oscillations emerge amidst a background of low-amplitude aperiodic fluctuations. As Re increases further, these intermittent bursts persist longer in time until they dominate the overall dynamics, causing the jet to transition fully to a periodic limit cycle. We identify this as Type-II Pomeau-Manneville intermittency by quantifying the statistical distribution of the duration of the aperiodic fluctuations at the onset of intermittency. This study shows that the transition to global instability in low-density jets is not always abrupt but can involve an intermediate state with characteristics of both the initial fixed point and the final limit cycle. This work was supported by the Research Grants Council of Hong Kong (Project No. 16235716 and 26202815).

Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake

Science.gov (United States)

Anson, R. Michael; Guo, Zhihong; de Cabo, Rafael; Iyun, Titilola; Rios, Michelle; Hagepanos, Adrienne; Ingram, Donald K.; Lane, Mark A.; Mattson, Mark P.

2003-01-01

Dietary restriction has been shown to have several health benefits including increased insulin sensitivity, stress resistance, reduced morbidity, and increased life span. The mechanism remains unknown, but the need for a long-term reduction in caloric intake to achieve these benefits has been assumed. We report that when C57BL/6 mice are maintained on an intermittent fasting (alternate-day fasting) dietary-restriction regimen their overall food intake is not decreased and their body weight is maintained. Nevertheless, intermittent fasting resulted in beneficial effects that met or exceeded those of caloric restriction including reduced serum glucose and insulin levels and increased resistance of neurons in the brain to excitotoxic stress. Intermittent fasting therefore has beneficial effects on glucose regulation and neuronal resistance to injury in these mice that are independent of caloric intake. PMID:12724520

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.

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

International Nuclear Information System (INIS)

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

2014-01-01

We study the radial evolution of the intermittency of density fluctuations in the fast solar wind. The study is performed by 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 timescales 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 the fast wind are rather intermittent and their level of intermittency, together with the amplitude of intermittent events, decreases with the distance from the Sun, at odds with the intermittency of both magnetic field and all 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. A remarkable, qualitative similarity with the behavior of plasma density fluctuations obtained from a numerical study of the nonlinear evolution of parametric instability in the solar wind supports the idea that this mechanism has an important role in governing density fluctuations in the inner heliosphere.

Sensitivity of intermittent streams to climate variations in the United States

Science.gov (United States)

Eng, K.

2015-12-01

There is growing interest in the effects of climate change on streamflows because of the potential negative effects on aquatic biota and water supplies. Previous studies of climate controls on flows have primarily focused on perennial streams, and few studies have examined the effect of climate variability on intermittent streams. Our objectives in this study were to (1) identify regions showing similar patterns of intermittency, and (2) evaluate the sensitivity of intermittent streams to historical variability in climate in the United States. This study was carried out at 265 intermittent streams by evaluating: (1) correlations among time series of flow metrics (number of zero-flow events, the average of the central 50% and largest 10% of flows) with precipitation (magnitudes, durations and intensity) and temperature, and (2) decadal changes in the seasonality and long-term trends of these flow metrics. Results identified five distinct seasonal patterns of flow intermittency: fall, fall-to-winter, non-seasonal, summer, and summer-to-winter intermittent streams. In addition, strong associations between the low-flow metrics and historical climate variability were found. However, the lack of trends in historical variations in precipitation results in no significant seasonal shifts or decade-to-decade trends in the low-flow metrics over the period of record (1950 to 2013).

High-dose phenobarbital with intermittent short-acting barbiturates for acute encephalitis with refractory, repetitive partial seizures.

Science.gov (United States)

Uchida, Takashi; Takayanagi, Masaru; Kitamura, Taro; Nishio, Toshiyuki; Numata, Yurika; Endo, Wakaba; Haginoya, Kazuhiro; Ohura, Toshihiro

2016-08-01

Acute encephalitis with refractory, repetitive partial seizures (AERRPS) is characterized by repetitive seizures during the acute and chronic phases and has a poor neurological outcome. Burst-suppression coma via continuous i.v. infusion of a short-acting barbiturate is used to terminate refractory seizures, but the severe side-effects of short-acting barbiturates are problematic. We report on a 9-year-old boy with AERRPS who was effectively treated with very-high-dose phenobarbital (VHDPB) combined with intermittent short-acting barbiturates. VHDPB side-effects were mild, especially compared with those associated with continuous i.v. infusion of short-acting barbiturates (dosage, 40-75 mg/kg/day; maximum blood level, 290 μg/mL). Using VHDPB as the main treatment, short-acting barbiturates were used intermittently and in small amounts. This is the first report to show that VHDPB, combined with intermittent short-acting barbiturates, can effectively treat AERRPS. After treatment, convulsions were suppressed and daily life continued, but intellectual impairment and high-level dysfunction remained. © 2016 Japan Pediatric Society.

Intermittent hypoxic episodes in preterm infants: do they matter?

Science.gov (United States)

Martin, Richard J; Wang, Katherine; Köroğlu, Ozge; Di Fiore, Juliann; Kc, Prabha

2011-01-01

Intermittent hypoxic episodes are typically a consequence of immature respiratory control and remain a troublesome challenge for the neonatologist. Furthermore, their frequency and magnitude are underestimated by clinically employed pulse oximeter settings. In extremely low birth weight infants the incidence of intermittent hypoxia progressively increases over the first 4 weeks of postnatal life, with a subsequent plateau followed by a slow decline beginning at weeks 6-8. Such episodic hypoxia/reoxygenation has the potential to sustain a proinflammatory cascade with resultant multisystem morbidity. This morbidity includes retinopathy of prematurity and impaired growth, as well as possible longer-term cardiorespiratory instability and poor neurodevelopmental outcome. Therapeutic approaches for intermittent hypoxic episodes comprise determination of optimal baseline saturation and careful titration of supplemental inspired oxygen, as well as xanthine therapy to prevent apnea of prematurity. In conclusion, characterization of the pathophysiologic basis for such intermittent hypoxic episodes and their consequences during early life is necessary to provide an evidence-based approach to their management. Copyright © 2011 S. Karger AG, Basel.

Phrenicotomy alters phrenic long-term facilitation following intermittent hypoxia in anesthetized rats

OpenAIRE

Sandhu, M. S.; Lee, K. Z.; Fregosi, R. F.; Fuller, D. D.

2010-01-01

Intermittent hypoxia (IH) can induce a persistent increase in neural drive to the respiratory muscles known as long-term facilitation (LTF). LTF of phrenic inspiratory activity is often studied in anesthetized animals after phrenicotomy (PhrX), with subsequent recordings being made from the proximal stump of the phrenic nerve. However, severing afferent and efferent axons in the phrenic nerve has the potential to alter the excitability of phrenic motoneurons, which has been hypothesized to be...

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...

Endovascular Therapy Is Effective for Leriche Syndrome with Deep Vein Thrombosis

Directory of Open Access Journals (Sweden)

Tasuku Higashihara

2015-01-01

Full Text Available A 65-year-old man presented to our hospital due to intermittent claudication and swelling in his left leg. He had Leriche syndrome and deep vein thrombosis. We performed endovascular therapy (EVT for Leriche syndrome, and a temporary filter was inserted in the inferior vena cava. He received anticoagulation therapy for deep vein thrombosis. The stenotic lesion in the terminal aorta was stented with an excellent postprocedural angiographic result and dramatic clinical improvement after EVT. This case suggests that EVT can be a treatment for Leriche syndrome.

[Effect of intermittent hypoxia of sleep apnea on embryonic rat cortical neurons in vitro].

Science.gov (United States)

Zhang, Chanjuan; Li, Yanzhong; Wang, Yan

2015-05-01

To investigate the effects of different pattens of intermittent hypoxia on the activity and apoptosis of primary cultured rat embryonic cortical neurons, and to evaluate the role of intermittent hypoxia in the mechanism of obstructive sleep syndrom induced cognitive function loss. The embryonic cerebral cortical neurons were cultured in vitro and were identified by immunofluorescence. Cultured neurons were randomly divided into intermittent hypoxia group, intermittent normal oxygen group, persistent hypoxia group and the control group, and intermittent hypoxia group was divided into five subgroups according to different frequency and time-bound. Neurons were exposed in different modes of hypoxia. MTT colorimetry was used to detect the viability of the neurons, and DAPI colorated measurement was used to calculate the percentages of neuron apoptosis. There were significantly different effects between all subgroups of intermittent hypoxia and the continued hypoxia group on neuronal activity and apoptosis (P Intermittent hypoxia groups with different frequency and time had no difference in neuronal activity and apoptosis (P > 0.05). The effect of intermittent hypoxia was more serious than that of continued hypoxia on neuronal activity and apoptosis; The impact of intermittent hypoxia on neuronal activity and apoptosis may be an important factor in obstructive sleep apnea related cognitive impairment.

Incidence and severity of root resorption in orthodontically moved premolars in dogs.

Science.gov (United States)

Maltha, J C; van Leeuwen, E J; Dijkman, G E H M; Kuijpers-Jagtman, A M

2004-05-01

To study treatment-related factors for external root resorption during orthodontic tooth movement. An experimental animal study. Department of Orthodontics and Oral Biology, University Medical Centre Nijmegen, The Netherlands. Twenty-four young adult beagle dogs. Mandibular premolars were bodily moved with continuous or intermittent controlled orthodontic forces of 10, 25, 50, 100, or 200 cN according to standardized protocols. At different points in time histomorphometry was performed to determine the severity of root resorption. Prevalence of root resorptions, defined as microscopically visible resorption lacunae in the dentin. Severity of resorption was defined by the length, relative length, depth, and surface area of each resorption area. The incidence of root resorption increased with the duration of force application. After 14-17 weeks of force application root resorption was found at 94% of the root surfaces at pressure sides. The effect of force magnitude on the severity of root resorption was not statistically significant. The severity of root resorption was highly related to the force regimen. Continuous forces caused significantly more severe root resorption than intermittent forces. A strong correlation (0.60 < r < 0.68) was found between the amount of tooth movement and the severity of root resorption. Root resorption increases with the duration of force application. The more teeth are displaced, the more root resorption will occur. Intermittent forces cause less severe root resorption than continuous forces, and force magnitude is probably not decisive for root resorption.

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...

Intermittent hypoxia in obese Zucker rats: cardiometabolic and inflammatory effects.

Science.gov (United States)

Briançon-Marjollet, Anne; Monneret, Denis; Henri, Marion; Joyeux-Faure, Marie; Totoson, Perle; Cachot, Sandrine; Faure, Patrice; Godin-Ribuot, Diane

2016-11-01

What is the central question of this study? This study addresses the relative impact of obesity and intermittent hypoxia in the pathophysiological process of obstructive sleep apnoea by investigating the metabolic, inflammatory and cardiovascular consequences of intermittent hypoxia in lean and obese Zucker rats. What is the main finding and its importance? We found that obesity and intermittent hypoxia have mainly distinct consequences on the investigated inflammatory and cardiometabolic parameters in Zucker rats. This suggests that, for a given severity of sleep apnea, the association of obesity and obstructive sleep apnoea may not necessarily be deleterious. Obstructive sleep apnoea is associated with obesity with a high prevalence, and both co-morbidities are independent cardiovascular risk factors. Intermittent hypoxia (IH) is thought to be the main factor responsible for the obstructive sleep apnoea-related cardiometabolic alterations. The aim of this study was to assess the respective impact of obesity and IH on the inflammatory and cardiometabolic state in rats. Lean and obese Zucker rats were exposed to normoxia or chronic IH, and we assessed metabolic and inflammatory parameters, such as plasma lipids and glucose, serum leptin and adiponectin, liver cytokines, nuclear factor-κB activity and cardiac endothelin-1 levels. Myocardial infarct size was also evaluated following in vitro ischaemia-reperfusion. Circulating lipids, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), leptin and adiponectin levels were higher in obese versus lean rats. Chronic IH did not have a significant impact on metabolic parameters in lean rats. In obese rats, IH increased glycaemia and HOMA-IR. Liver interleukin-6 and tumour necrosis factor-α levels were elevated in lean rats exposed to IH; obesity prevented the increase in interleukin-6 but not in tumour necrosis factor-α. Finally, IH exposure enhanced myocardial sensitivity to infarction in both lean and

On intermittent flow characteristics of gas–liquid two-phase flow

Energy Technology Data Exchange (ETDEWEB)

Thaker, Jignesh; Banerjee, Jyotirmay, E-mail: jbaner@gmail.com

2016-12-15

Highlights: • Unified correlations for intermittent flow characteristics are developed. • Influence of inflow conditions on intermittent flow characteristics is analysed. • Developed correlations can be used for effective design of piping components. - Abstract: Flow visualisation experiments are reported for intermittent regime of gas–liquid two-phase flow. Intermittent flow characteristics, which include plug/slug frequency, liquid plug/slug velocity, liquid plug/slug length, and plug/slug bubble length are determined by image processing of flow patterns captured at a rate of 1600 frames per second (FPS). Flow characteristics are established as a function of inlet superficial velocity of both the phases (in terms of Re{sub SL} and Re{sub SG}). The experimental results are first validated with the existing correlations for slug flow available in literature. It is observed that the correlations proposed in literature for slug flow do not accurately predict the flow characteristics in the plug flow regime. The differences are clearly highlighted in this paper. Based on the measured database for both plug and slug flow regime, modified correlations for the intermittent flow regime are proposed. The correlations reported in the present paper, which also include plug flow characteristics will aid immensely to the effective design and optimization of operating conditions for safer operation of two-phase flow piping systems.

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.

Pathophysiology, diagnosis and treatment of intermittent claudication in patients with lumbar canal stenosis.

Science.gov (United States)

Kobayashi, Shigeru

2014-04-18

Spinal nerve roots have a peculiar structure, different from the arrangements in the peripheral nerve. The nerve roots are devoid of lymphatic vessels but are immersed in the cerebrospinal fluid (CSF) within the subarachnoid space. The blood supply of nerve roots depends on the blood flow from both peripheral direction (ascending) and the spinal cord direction (descending). There is no hypovascular region in the nerve root, although there exists a so-called water-shed of the bloodstream in the radicular artery itself. Increased mechanical compression promotes the disturbance of CSF flow, circulatory disturbance starting from the venous congestion and intraradicular edema formation resulting from the breakdown of the blood-nerve barrier. Although this edema may diffuse into CSF when the subarachnoid space is preserved, the endoneurial fluid pressure may increase when the area is closed by increased compression. On the other hand, the nerve root tissue has already degenerated under the compression and the numerous macrophages releasing various chemical mediators, aggravating radicular symptoms that appear in the area of Wallerian degeneration. Prostaglandin E1 (PGE1) is a potent vasodilator as well as an inhibitor of platelet aggregation and has therefore attracted interest as a therapeutic drug for lumbar canal stenosis. However, investigations in the clinical setting have shown that PGE1 is effective in some patients but not in others, although the reason for this is unclear.

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…

Intermittent Hypoxia Alters Gene Expression in Peripheral Blood Mononuclear Cells of Healthy Volunteers.

Science.gov (United States)

Polotsky, Vsevolod Y; Bevans-Fonti, Shannon; Grigoryev, Dmitry N; Punjabi, Naresh M

2015-01-01

Obstructive sleep apnea is associated with high cardiovascular morbidity and mortality. Intermittent hypoxia of obstructive sleep apnea is implicated in the development and progression of insulin resistance and atherosclerosis, which have been attributed to systemic inflammation. Intermittent hypoxia leads to pro-inflammatory gene up-regulation in cell culture, but the effects of intermittent hypoxia on gene expression in humans have not been elucidated. A cross-over study was performed exposing eight healthy men to intermittent hypoxia or control conditions for five hours with peripheral blood mononuclear cell isolation before and after exposures. Total RNA was isolated followed by gene microarrays and confirmatory real time reverse transcriptase PCR. Intermittent hypoxia led to greater than two fold up-regulation of the pro-inflammatory gene toll receptor 2 (TLR2), which was not increased in the control exposure. We hypothesize that up-regulation of TLR2 by intermittent hypoxia may lead to systemic inflammation, insulin resistance and atherosclerosis in patients with obstructive sleep apnea.

Obstructive sleep apnea and cancer: effects of intermittent hypoxia?

Science.gov (United States)

Kukwa, Wojciech; Migacz, Ewa; Druc, Karolina; Grzesiuk, Elzbieta; Czarnecka, Anna M

2015-01-01

Obstructive sleep apnea (OSA) is a common disorder characterized by pauses in regular breathing. Apneic episodes lead to recurrent hypoxemia-reoxygenation cycles with concomitant cellular intermittent hypoxia. Studies suggest that intermittent hypoxia in OSA may influence tumorigenesis. This review presents recent articles on the potential role of OSA in cancer development. Relevant research has focused on: molecular pathways mediating the influence of intermittent hypoxia on tumor physiology, animal and epidemiological human studies linking OSA and cancer. Current data relating OSA to risk of neoplastic disease remain scarce, but recent studies reveal the potential for a strong relation. More work is, therefore, needed on the impact of OSA on many cancer-related aspects. Results may offer enlightenment for improved cancer diagnosis and treatment.

Three hours of intermittent hypoxia increases circulating glucose levels in healthy adults.

Science.gov (United States)

Newhouse, Lauren P; Joyner, Michael J; Curry, Timothy B; Laurenti, Marcello C; Man, Chiara Dalla; Cobelli, Claudio; Vella, Adrian; Limberg, Jacqueline K

2017-01-01

An independent association exists between sleep apnea and diabetes. Animal models suggest exposure to intermittent hypoxia, a consequence of sleep apnea, results in altered glucose metabolism and fasting hyperglycemia. However, it is unknown if acute exposure to intermittent hypoxia increases glucose concentrations in nondiabetic humans. We hypothesized plasma glucose would be increased from baseline following 3 h of intermittent hypoxia in healthy humans independent of any effect on insulin sensitivity. Eight (7M/1F, 21-34 years) healthy subjects completed two study visits randomized to 3 h of intermittent hypoxia or continuous normoxia, followed by an oral glucose tolerance test. Intermittent hypoxia consisted of 25 hypoxic events per hour where oxygen saturation (SpO 2 ) was significantly reduced (Normoxia: 97 ± 1%, Hypoxia: 90 ± 2%, P  0.05). In contrast, circulating glucose concentrations were increased after 3 h of intermittent hypoxia when compared to baseline (5.0 ± 0.2 vs. 5.3 ± 0.2 mmol/L, P = 0.01). There were no detectable changes in insulin sensitivity following intermittent hypoxia when compared to continuous normoxia, as assessed by the oral glucose tolerance test (P > 0.05). Circulating glucose is increased after 3 h of intermittent hypoxia in healthy humans, independent of any lasting changes in insulin sensitivity. These novel findings could explain, in part, the high prevalence of diabetes in patients with sleep apnea and warrant future studies to identify underlying mechanisms. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Effekten af Ginkgo biloba-ekstrakt hos patienter med claudicatio intermittens

DEFF Research Database (Denmark)

Drabaek, H; Petersen, J R; Wïnberg, N

1996-01-01

Eighteen patients with stable intermittent claudication were randomized in a double blind cross-over study comparing the effects of the Ginkgo biloba extract GB-8 at a dose of 120 mg o.d. with placebo. All patients were treated for three months with the active extract and three months with placebo...... of concentration, and inability to remember. Short-term memory was objectively assessed. We did not find any significant changes in either peripheral blood pressures, walking distances or the severity of leg pain. Systemic blood pressure was reduced both by placebo and GB-8. The impairment of concentration...... and the inability to remember were both reduced, when comparing results during active treatment to placebo. Short-term memory did not change significantly. In conclusion, our study has shown that treatment with the Ginkgo biloba extract GB-8 improves some cognitive functions in elderly patients with moderate...

Intermittent hypercapnic hypoxia during sleep does not induce ventilatory long-term facilitation in healthy males.

Science.gov (United States)

Deacon, Naomi L; McEvoy, R Doug; Stadler, Daniel L; Catcheside, Peter G

2017-09-01

Intermittent hypoxia-induced ventilatory neuroplasticity is likely important in obstructive sleep apnea pathophysiology. Although concomitant CO 2 levels and arousal state critically influence neuroplastic effects of intermittent hypoxia, no studies have investigated intermittent hypercapnic hypoxia effects during sleep in humans. Thus the purpose of this study was to investigate if intermittent hypercapnic hypoxia during sleep induces neuroplasticity (ventilatory long-term facilitation and increased chemoreflex responsiveness) in humans. Twelve healthy males were exposed to intermittent hypercapnic hypoxia (24 × 30 s episodes of 3% CO 2 and 3.0 ± 0.2% O 2 ) and intermittent medical air during sleep after 2 wk washout period in a randomized crossover study design. Minute ventilation, end-tidal CO 2 , O 2 saturation, breath timing, upper airway resistance, and genioglossal and diaphragm electromyograms were examined during 10 min of stable stage 2 sleep preceding gas exposure, during gas and intervening room air periods, and throughout 1 h of room air recovery. There were no significant differences between conditions across time to indicate long-term facilitation of ventilation, genioglossal or diaphragm electromyogram activity, and no change in ventilatory response from the first to last gas exposure to suggest any change in chemoreflex responsiveness. These findings contrast with previous intermittent hypoxia studies without intermittent hypercapnia and suggest that the more relevant gas disturbance stimulus of concomitant intermittent hypercapnia frequently occurring in sleep apnea influences acute neuroplastic effects of intermittent hypoxia. These findings highlight the need for further studies of intermittent hypercapnic hypoxia during sleep to clarify the role of ventilatory neuroplasticity in the pathophysiology of sleep apnea. NEW & NOTEWORTHY Both arousal state and concomitant CO 2 levels are known modulators of the effects of intermittent hypoxia on

Shape of power spectrum of intermittent chaos

International Nuclear Information System (INIS)

So, B.C.; Mori, H.

1984-01-01

Power spectra of intermittent chaos are calculated analytically. It is found that the power spectrum near onset point consists of a large number of Lorentzian lines with two peaks around frequencies ω = 0 and ω = ω 0 , where ω 0 is a fundamental frequency of a periodic orbit before the onset point, and furthermore the envelope of lines around ω = 0 obeys the power law 1/ + ω +2 , whereas the envelope around ω 0 obeys 1/ + ω-ω 0 +4 . The universality of these power law dependence in a certain class of intermittent chaos are clarified from a phenomenological view point. (author)

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.

Critical behavior of the Lyapunov exponent in type-III intermittency

International Nuclear Information System (INIS)

Alvarez-Llamoza, O.; Cosenza, M.G.; Ponce, G.A.

2008-01-01

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 β 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 β varies on the interval 0 ≤ β < 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 β 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

Intermittently chaotic oscillations for a differential-delay equation with Gaussian nonlinearity

Science.gov (United States)

Hamilton, Ian

1992-01-01

For a differential-delay equation the time dependence of the variable is a function of the variable at a previous time. We consider a differential-delay equation with Gaussian nonlinearity that displays intermittent chaos. Although not the first example of a differential-delay equation that displays such behavior, for this example the intermittency is classified as type III, and the origin of the intermittent chaos may be qualitatively understood from the limiting forms of the equation for large and small variable magnitudes.

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.

Physiologic basis for intermittent hypoxic episodes in preterm infants.

Science.gov (United States)

Martin, R J; Di Fiore, J M; Macfarlane, P M; Wilson, C G

2012-01-01

Intermittent hypoxic episodes are typically a consequence of immature respiratory control and remain a troublesome challenge for the neonatologist. Furthermore, their frequency and magnitude are commonly underestimated by clinically employed pulse oximeter settings. In extremely low birth weight infants the incidence of intermittent hypoxia [IH] progressively increases over the first 4 weeks of postnatal life, with a subsequent plateau followed by a slow decline beginning at weeks six to eight. Over this period of unstable respiratory control, increased oxygen-sensitive peripheral chemoreceptor activity has been associated with a higher incidence of apnea of prematurity. In contrast, infants with bronchopulmonary dysplasia [chronic neonatal lung disease] exhibit decreased peripheral chemosensitivity, although the effect on respiratory stability in this population is unclear. Such episodic hypoxia/reoxygenation in early life has the potential to sustain a proinflammatory cascade with resultant multisystem, including respiratory, morbidity. Therapeutic approaches for intermittent hypoxic episodes comprise careful titration of baseline or supplemental inspired oxygen as well as xanthine therapy to prevent apnea of prematurity. Characterization of the pathophysiologic basis for such intermittent hypoxic episodes and their consequences during early life is necessary to provide an evidence-based approach to their management.

Recurrent severe vomiting due to hyperthyroidism

OpenAIRE

Chen, Li-ying; Zhou, Bo; Chen, Zhou-wen; Fang, Li-zheng

2010-01-01

Thyrotoxicosis may present in many ways; severe vomiting as a prominent symptom of thyrotoxicosis is uncommon. In this paper, we report a 24-year-old Chinese male with hyperthyroidism who presented with recurrent severe vomiting. The patient had had intermittent vomiting for seven years and had lost approximately 15 kg of weight. Gastroscopic examinations revealed chronic gastritis and one occasion peptic ulcer. He was treated with antacid and proton pump inhibitors, but his symptoms had no r...

Intermittent Anisotropic Turbulence Detected by THEMIS in the Magnetosheath

Science.gov (United States)

Macek, W. M.; Wawrzaszek, A.; Kucharuk, B.; Sibeck, D. G.

2017-12-01

Following our previous study of Time History of Events and Macroscale Interactions during Substorms (THEMIS) data, we consider intermittent turbulence in the magnetosheath depending on various conditions of the magnetized plasma behind the Earth’s bow shock and now also near the magnetopause. Namely, we look at the fluctuations of the components of the Elsässer variables in the plane perpendicular to the scale-dependent background magnetic fields and along the local average ambient magnetic fields. We have shown that Alfvén fluctuations often exhibit strong anisotropic non-gyrotropic turbulent intermittent behavior resulting in substantial deviations of the probability density functions from a normal Gaussian distribution with a large kurtosis. In particular, for very high Alfvénic Mach numbers and high plasma beta, we have clear anisotropy with non-Gaussian statistics in the transverse directions. However, along the magnetic field, the kurtosis is small and the plasma is close to equilibrium. On the other hand, intermittency becomes weaker for moderate Alfvén Mach numbers and lower values of the plasma parameter beta. It also seems that the degree of intermittency of turbulence for the outgoing fluctuations propagating relative to the ambient magnetic field is usually similar as for the ingoing fluctuations, which is in agreement with approximate equipartition of energy between these oppositely propagating Alfvén waves. We believe that the different characteristics of this intermittent anisotropic turbulent behavior in various regions of space and astrophysical plasmas can help identify nonlinear structures responsible for deviations of the plasma from equilibrium.

Wave-Number Spectra and Intermittency in the Terrestrial Foreshock Region

International Nuclear Information System (INIS)

Narita, Y.; Glassmeier, K.-H.; Treumann, R. A.

2006-01-01

Wave-number spectra of magnetic field fluctuations are directly determined in the terrestrial foreshock region (upstream of a quasiparallel collisionless shock wave) using four-point Cluster spacecraft measurements. The spectral curve is characterized by three ranges reminiscent of turbulence: energy injection, inertial, and dissipation range. The spectral index for the inertial range spectrum is close to Kolmogorov's slope, -5/3. On the other hand, the fluctuations are highly anisotropic and intermittent perpendicular to the mean magnetic field direction. These results suggest that the foreshock is in a weakly turbulent and intermittent state in which parallel propagating Alfven waves interact with one another, resulting in the phase coherence or the intermittency

Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

National Research Council Canada - National Science Library

Wang, Zhou

2004-01-01

.... Intermittent androgen ablation therapy may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

National Research Council Canada - National Science Library

Wang, Zhou

2005-01-01

.... Intermittent androgen ablation therapy may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

National Research Council Canada - National Science Library

Wang, Zhou

2003-01-01

.... Intermittent androgen ablation therapy may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

New advances on chaotic intermittency and its applications

CERN Document Server

Elaskar, Sergio

2017-01-01

One of the most important routes to chaos is the chaotic intermittency. However, there are many cases that do not agree with the classical theoretical predictions. In this book, an extended theory for intermittency in one-dimensional maps is presented. A new general methodology to evaluate the reinjection probability density function (RPD) is developed in Chapters 5 to 8. The key of this formulation is the introduction of a new function, called M(x), which is used to calculate the RPD function. The function M(x) depends on two integrals. This characteristic reduces the influence on the statistical fluctuations in the data series. Also, the function M(x) is easy to evaluate from the data series, even for a small number of numerical or experimental data. As a result, a more general form for the RPD is found; where the classical theory based on uniform reinjection is recovered as a particular case. The characteristic exponent traditionally used to characterize the intermittency type, is now a function depending ...

Multiparticle correlations and intermittency in high energy collisions

International Nuclear Information System (INIS)

Bozek, P.

1992-01-01

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

Multiparticle correlations and intermittency in high energy collisions

International Nuclear Information System (INIS)

Bozek, P.

1992-01-01

An 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 (lD) cellular-automaton (CA) and a lD forest-fire model is studied. On the example of the noncritical lD Ising model the difficulties of the scaled factorial moment (SFM) method in extracting genuine scaling behaviour are illustrated. The problem of the finite-size effect in connection to the dimensional projection can be easily exemplified in the case of the 2D critical system with conformal symmetry. (R.P.) 122 refs., 38 figs., 3 tabs

[Intermittent Explosive Disorder: A Controversial Diagnosis].

Science.gov (United States)

Zapata, Juan Pablo; Palacio, Juan David

2016-01-01

Intermittent explosive disorder (IED) is aan externalizing externalising disorder characterized characterised by recurrent aggression episodes. Even though this disorder was described several decades ago, and it carries personal and social consequences, there is little in the medical scientific literature on this. bibliographic production about it is scanty. To perform a conceptualization conceptualisation of this disorder, through the review and bibliometric analysis of the available scientific articles. A search was performed in databases with the english English terms intermittent explosive disorder, impulse disorders control [MeSH], in combination with other terms. A bibliometric analysis in the GoPubMed® search engineer was also performed using all data obtained in the search. was also perfomed. IED prevalence ranges from 1.4% to 7%, it presents more frequently during middle adolescence, and with more noticeable repercussions in men males than in womenfemales. The psychopathological core of IED is the impulsive aggressive behaviour that presents in the form of «attacks» that occurs in response to a lower precipitating stimulus. Scientific publications about IED are few and relatively recent, and the vast majority is provided bycomes from the United States (56.56%), and headed by a single author. This fact highlights the need to replicate the findings described about the IED in order to demonstrate the validity and reliability of its diagnostic criteria. It is possible that doubts about the existence of a diagnosis lead have led to such a scant literature about the IED. Available studies about IED allow have allowed characterizing a group of subjects with episodes of impulsive aggression to be characterised, but this description requires replication in different latitudesneeds to be repeated in different areas. Copyright © 2015 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

Influence of obstructive sleep apnea on fatty liver disease: role of chronic intermittent hypoxia.

Science.gov (United States)

Türkay, Cansel; Ozol, Duygu; Kasapoğlu, Benan; Kirbas, Ismail; Yıldırım, Zeki; Yiğitoğlu, Ramazan

2012-02-01

Currently the common pathogenetic mechanisms in nonalcoholic fatty liver disease (NAFLD) and obstructive sleep apnea (OSA) are gaining increased attention. The aim of this study is to find out the influence of chronic intermittent hypoxemia and OSA related parameters to the severity of NAFLD. We examined the liver functions tests and ultrasonographic data of liver as well as markers of OSA severity (apnea-hypopnea index [AHI], oxygen desaturation index, minimum oxygen saturation, percentage of time spent with S(pO(2)) hypoxia during sleep. The prevalence of NAFLD was higher in patients with severe OSA, suggesting a role for nocturnal hypoxemia in the pathogenesis of fatty liver disease.

Enhancement of Intermittent Androgen Ablation Therapy by Finasteride Administration in Animal Models

National Research Council Canada - National Science Library

Wang, Zhou

2006-01-01

.... Intermittent androgen ablation therapy (IAAT) may slow down the development of androgen refractory tumors because intermittent recovery of androgens can induce differentiation of prostatic epithelial cells...

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.

Pulsar wind model for the spin-down behavior of intermittent pulsars

Energy Technology Data Exchange (ETDEWEB)

Li, L.; Tong, H.; Yan, W. M.; Yuan, J. P.; Wang, N. [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi, Xinjiang 830011 (China); Xu, R. X., E-mail: tonghao@xao.ac.cn [School of Physics, Peking University, Beijing (China)

2014-06-10

Intermittent pulsars are part-time radio pulsars. They have higher slow down rates in the on state (radio-loud) than in the off state (radio-quiet). This gives evidence that particle wind may play an important role in pulsar spindown. The effect of particle acceleration is included in modeling the rotational energy loss rate of the neutron star. Applying the pulsar wind model to the three intermittent pulsars (PSR B1931+24, PSR J1841–0500, and PSR J1832+0029) allows their magnetic fields and inclination angles to be calculated simultaneously. The theoretical braking indices of intermittent pulsars are also given. In the pulsar wind model, the density of the particle wind can always be the Goldreich-Julian density. This may ensure that different on states of intermittent pulsars are stable. The duty cycle of particle wind can be determined from timing observations. It is consistent with the duty cycle of the on state. Inclination angle and braking index observations of intermittent pulsars may help to test different models of particle acceleration. At present, the inverse Compton scattering induced space charge limited flow with field saturation model can be ruled out.

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

Science.gov (United States)

Li, Liaoliao; Wang, Zhi; Zuo, Zhiyi

2013-01-01

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.

Enhancing wastewater degradation and biogas production by intermittent operation of UASB reactors

International Nuclear Information System (INIS)

Nadais, Helena; Barbosa, Marta; Capela, Isabel; Arroja, Luis; Ramos, Christian G.; Grilo, Andre; Sousa, Silvia A.; Leitao, Jorge H.

2011-01-01

The present work establishes intermittent operation of UASB reactors as a novel form of enhancing the anaerobic degradation of complex wastewaters and its conversion to usable biogas. Results show that the average methane production rate is 25% higher with the intermittent operation than with the continuous mode, meaning that it could produce 25% more electricity or heat. The methanization efficiency obtained in intermittent UASB reactors is around 20% higher than in the continuous systems, confirming a higher biological degradation of the substrates. It has been suggested that intermittent operation causes a forced adaptation of the biomass towards the degradation of complex substrates and results from morphological analyses of the biomass developed in intermittent and continuous UASB reactors showed marked differences between them. In order to gain a deeper knowledge on how microbial populations are affected by these operational parameters, a strategy involving the amplification, cloning, and analysis of the nucleotide sequences of genes encoding the 16S ribosomal RNA was undertaken and is described in this work. This strategy allowed the identification of a total of 49 different sequences. Results from the molecular characterization of the microbial populations are consistent with the higher methanization efficiency of the intermittent mode of operation.

Intermittency inhibited by transport: An exactly solvable model

Science.gov (United States)

Zanette, Damián H.

1994-04-01

Transport is incorporated in a discrete-time stochastic model of a system undergoing autocatalytic reactions of the type A-->2A and A-->0, whose population field is known to exhibit spatiotemporal intermittency. The temporal evolution is exactly solved, and it is shown that if the transport process is strong enough, intermittency is inhibited. This inhibition is nonuniform, in the sense that, as transport is strengthened, low-order population moments are affected before the high-order ones. Numerical simulations are presented to support the analytical results.

Melatonin Protects the Heart, Lungs and Kidneys from Oxidative Stress under Intermittent Hypobaric Hypoxia in Rats

Directory of Open Access Journals (Sweden)

Jorge G Farías

2012-01-01

Full Text Available Melatonin (N-acetyl-5-methoxytryptamine is the main secretory product of the pineal gland in all mammals including humans, but it is also produced in other organs. It has been previously demonstrated to be a powerful organ-protective substance under oxidative stress conditions. The aim of this study was to evaluate the protective effect of melatonin in several organs such as heart, lung, kidney, and of the reproductive system, such as testis and epididymis in animals exposed to intermittent hypobaric hypoxia and therefore exposed to oxidative stress and analyzed by lipid peroxidation. Ten-week-old male Wistar rats were divided into 6 groups for 96 hours during 32 days under: 1 Normobaric conditions, 2 plus physiologic solution, 3 plus melatonin, 4 intermittent hypobaric hypoxia, 5 plus physiologic solution and 6 plus melatonin. The animals were injected with melatonin (10 mg/kg body weight at an interval of 96 hours during 32 days. Results indicated that melatonin decreased lipid peroxidation in heart, kidneys and lung under intermittent hypobaric hypoxia conditions. However, it did not exhibit any protective effect in liver, testis, epididymis and sperm count.

Intermittent Hypoxic Episodes in Preterm Infants: Do They Matter?

OpenAIRE

Martin, Richard J.; Wang, Katherine; Köroğlu, Özge; Di Fiore, Juliann; Kc, Prabha

2011-01-01

Intermittent hypoxic episodes are typically a consequence of immature respiratory control and remain a troublesome challenge for the neonatologist. Furthermore, their frequency and magnitude are underestimated by clinically employed pulse oximeter settings. In extremely low birth weight infants the incidence of intermittent hypoxia progressively increases over the first 4 weeks of postnatal life, with a subsequent plateau followed by a slow decline beginning at weeks 6–8. Such episodic hypoxi...

The Effects of Intermittent Drinking Water Supply in Arraiján, Panama

OpenAIRE

Erickson, John Joseph

2016-01-01

Over three hundred million people throughout the world receive supply from piped drinking water distribution networks that operate intermittently. This dissertation evaluates the effects of intermittent supply on water quality, pipe damage and service reliability in four study zones (one continuous and three intermittent) in a peri-urban drinking water distribution network in Arraiján, Panama. Normal water quality in all zones was good, with 97% of routine water quality grab samples from the ...

Optimal Dynamics of Intermittent Water Supply

Science.gov (United States)

Lieb, Anna; Wilkening, Jon; Rycroft, Chris

2014-11-01

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. These consequences include degradation of distribution system components, compromised water quality, and inequitable water availability. The goal of this work is to model the important dynamics and identify operating conditions that mitigate certain negative effects of intermittent water supply. Specifically, we will look at valve parameters occurring as boundary conditions in a network model of transient, transition flow through closed pipes. Optimization will be used to find boundary values to minimize pressure gradients and ensure equitable water availability.

Intermittent hypoxia simulating obstructive sleep apnea causes pulmonary inflammation and activates the Nrf2/HO-1 pathway.

Science.gov (United States)

Wang, Yeying; Chai, Yanling; He, Xiaojie; Ai, Li; Sun, Xia; Huang, Yiling; Li, Yongxia

2017-10-01

Obstructive sleep apnea (OSA) is a disorder with high morbidity in adults. OSA damages multiple organs and tissues, including the cardiovascular and cerebrovascular systems, the metabolism system, the lungs, liver and heart. OSA-induced damage is earliest and greatest to the pulmonary tissue. The present study established a rat OSA model of differing severity by inducing intermittent hypoxia with different concentrations of O 2 and it was determined that OSA caused a severe oxidative stress response and pulmonary inflammation in a dose-dependent manner. OSA increased serum levels of C-reactive protein and 8-isoprostane and elevated the expression of malondialdehyde, tumor necrosis factor α, interleukin (IL)-1β and IL-6 in the pulmonary tissue. Furthermore, the expression of two important antioxidants, superoxide dismutase and glutathione, was downregulated following intermittent hypoxia. By contrast, levels of cylooxygenase 2 and inducible nitric oxide synthase, which are crucial in the antioxidative response, increased. In addition, OSA activates the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase (OH)-1 antioxidative signaling pathway. Finally, all increases and decreases in levels of inflammatory and antioxidative substances were dependent on oxygen concentrations. Therefore, the present study demonstrated that OSA, simulated by intermittent hypoxia, caused an oxidative stress response and pulmonary inflammation, and activated the canonical antioxidative Nrf2/HO-1 signaling pathway in a dose-dependent manner. These results may facilitate the development of clinical therapies to treat pulmonary diseases caused by OSA.

Protective effects of intermittent hypoxia on brain and memory in a mouse model of apnea of prematurity

OpenAIRE

Bouslama, Myriam; Adle-Biassette, Homa; Ramanantsoa, Nelina; Bourgeois, Thomas; Bollen, Bieke; Brissaud, Olivier; Matrot, Boris; Gressens, Pierre; Gallego, Jorge

2015-01-01

Apnea of prematurity (AOP) is considered a risk factor for neurodevelopmental disorders in children based on epidemiological studies. This idea is supported by studies in newborn rodents in which exposure to intermittent hypoxia (IH) as a model of AOP significantly impairs development. However, the severe IH used in these studies may not fully reflect the broad spectrum of AOP severity. Considering that hypoxia appears neuroprotective under various conditions, we hypothesized that moderate IH...

Wave-number spectra and intermittency in the terrestrial foreshock region.

Science.gov (United States)

Narita, Y; Glassmeier, K-H; Treumann, R A

2006-11-10

Wave-number spectra of magnetic field fluctuations are directly determined in the terrestrial foreshock region (upstream of a quasiparallel collisionless shock wave) using four-point Cluster spacecraft measurements. The spectral curve is characterized by three ranges reminiscent of turbulence: energy injection, inertial, and dissipation range. The spectral index for the inertial range spectrum is close to Kolmogorov's slope, -5/3. On the other hand, the fluctuations are highly anisotropic and intermittent perpendicular to the mean magnetic field direction. These results suggest that the foreshock is in a weakly turbulent and intermittent state in which parallel propagating Alfvén waves interact with one another, resulting in the phase coherence or the intermittency.

Dynamic analysis with a fractional-order chaotic system for estimation of peripheral arterial disease in diabetic foot

Science.gov (United States)

Li, Chien-Ming; Du, Yi-Chun; Wu, Jian-Xing; Lin, Chia-Hung; Ho, Yueh-Ren; Chen, Tainsong

2013-08-01

Lower-extremity peripheral arterial disease (PAD) is caused by narrowing or occlusion of vessels in patients like type 2 diabetes mellitus, the elderly and smokers. Patients with PAD are mostly asymptomatic; typical early symptoms of this limb-threatening disorder are intermittent claudication and leg pain, suggesting the necessity for accurate diagnosis by invasive angiography and ankle-brachial pressure index. This index acts as a gold standard reference for PAD diagnosis and categorizes its severity into normal, low-grade and high-grade, with respective cut-off points of ≥0.9, 0.9-0.5 and diabetics and 11 healthy adults, with analysis of dynamic errors based on various butterfly motion patterns, and color relational analysis as classifier for pattern recognition. The results show that the classification of PAD severity among these testees was achieved with high accuracy and efficiency. This noninvasive methodology potentially provides timing and accessible feedback to patients with asymptomatic PAD and their physicians for further invasive diagnosis or strict management of risk factors to intervene in the disease progression.

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

Directory of Open Access Journals (Sweden)

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

Chronic intermittent hypoxia induces atherosclerosis via activation of adipose angiopoietin-like 4.

Science.gov (United States)

Drager, Luciano F; Yao, Qiaoling; Hernandez, Karen L; Shin, Mi-Kyung; Bevans-Fonti, Shannon; Gay, Jason; Sussan, Thomas E; Jun, Jonathan C; Myers, Allen C; Olivecrona, Gunilla; Schwartz, Alan R; Halberg, Nils; Scherer, Philipp E; Semenza, Gregg L; Powell, David R; Polotsky, Vsevolod Y

2013-07-15

Obstructive sleep apnea is a risk factor for dyslipidemia and atherosclerosis, which have been attributed to chronic intermittent hypoxia (CIH). Intermittent hypoxia inhibits a key enzyme of lipoprotein clearance, lipoprotein lipase, and up-regulates a lipoprotein lipase inhibitor, angiopoietin-like 4 (Angptl4), in adipose tissue. The effects and mechanisms of Angptl4 up-regulation in sleep apnea are unknown. To examine whether CIH induces dyslipidemia and atherosclerosis by increasing adipose Angptl4 via hypoxia-inducible factor-1 (HIF-1). ApoE(-/-) mice were exposed to intermittent hypoxia or air for 4 weeks while being treated with Angptl4-neutralizing antibody or vehicle. In vehicle-treated mice, hypoxia increased adipose Angptl4 levels, inhibited adipose lipoprotein lipase, increased fasting levels of plasma triglycerides and very low density lipoprotein cholesterol, and increased the size of atherosclerotic plaques. The effects of CIH were abolished by the antibody. Hypoxia-induced increases in plasma fasting triglycerides and adipose Angptl4 were not observed in mice with germline heterozygosity for a HIF-1α knockout allele. Transgenic overexpression of HIF-1α in adipose tissue led to dyslipidemia and increased levels of adipose Angptl4. In cultured adipocytes, constitutive expression of HIF-1α increased Angptl4 levels, which was abolished by siRNA. Finally, in obese patients undergoing bariatric surgery, the severity of nocturnal hypoxemia predicted Angptl4 levels in subcutaneous adipose tissue. HIF-1-mediated increase in adipose Angptl4 and the ensuing lipoprotein lipase inactivation may contribute to atherosclerosis in patients with sleep apnea.

On the degrees-of-freedom of the MIMO three-way channel with intermittent connectivity

KAUST Repository

Chaaban, Anas

2017-08-29

The degrees-of-freedom (DoF) of the multi-antenna three-way channel (3WC) with an intermittent node is studied. Special attention is given to the impact of adaptation when the intermittent node has the largest number of antennas. A non-adaptive transmission scheme based on interference alignment, zero-forcing, and erasure-channel treatment is proposed, and its corresponding DoF region is derived. Then, it is shown that this scheme achieves the sum-DoF of the intermittent channel, in addition to the DoF region of the nonintermittent one. Thus, adaptation is not necessary from those perspectives. To the contrary, it is shown that adaptation is necessary for achieving the DoF region of the intermittent case. This is shown by deriving an outer bound for the intermittent channel with nonadaptive encoding, and proposing an adaptive scheme which achieves DoF tuples outside this bound. This highlights the importance of cooperation in this intermittent network.

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

Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials.

Science.gov (United States)

Seimon, Radhika V; Roekenes, Jessica A; Zibellini, Jessica; Zhu, Benjamin; Gibson, Alice A; Hills, Andrew P; Wood, Rachel E; King, Neil A; Byrne, Nuala M; Sainsbury, Amanda

2015-12-15

Energy restriction induces physiological effects that hinder further weight loss. Thus, deliberate periods of energy balance during weight loss interventions may attenuate these adaptive responses to energy restriction and thereby increase the efficiency of weight loss (i.e. the amount of weight or fat lost per unit of energy deficit). To address this possibility, we systematically searched MEDLINE, PreMEDLINE, PubMed and Cinahl and reviewed adaptive responses to energy restriction in 40 publications involving humans of any age or body mass index that had undergone a diet involving intermittent energy restriction, 12 with direct comparison to continuous energy restriction. Included publications needed to measure one or more of body weight, body mass index, or body composition before and at the end of energy restriction. 31 of the 40 publications involved 'intermittent fasting' of 1-7-day periods of severe energy restriction. While intermittent fasting appears to produce similar effects to continuous energy restriction to reduce body weight, fat mass, fat-free mass and improve glucose homeostasis, and may reduce appetite, it does not appear to attenuate other adaptive responses to energy restriction or improve weight loss efficiency, albeit most of the reviewed publications were not powered to assess these outcomes. Intermittent fasting thus represents a valid--albeit apparently not superior--option to continuous energy restriction for weight loss. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Intermittent hypoxia in childhood: the harmful consequences versus potential benefits of therapeutic uses

Directory of Open Access Journals (Sweden)

Tatiana V. Serebrovskaya

2015-05-01

Full Text Available Intermittent hypoxia often occurs in early infancy in both preterm and term infants and especially at 36 to 44 weeks postmenstrual age. These episodes of intermittent hypoxia could result from sleep-disordered breathing or may be temporally unrelated to apnea or bradycardia events. There are numerous reports indicating adverse effects of intermittent hypoxia on development, behavior, academic achievement and cognition in children with sleep apnea syndrome. It remains uncertain the exact causative relationship between the neurocognitive and behavioral morbidities and intermittent hypoxia and/or its associated sleep fragmentation. On the other hand, well-controlled and moderate intermittent hypoxia conditioning/training has been used in sick children for treating their various forms of bronchial asthma, allergic dermatoses, autoimmune thyroiditis, cerebral palsy, and obesity. This review article provides an updated and impartial analysis on the currently available evidence in supporting either side of the seemingly contradictory scenarios. We wish to stimulate a comprehensive understanding of such a complex physiological phenomenon as intermittent hypoxia, which may be accompanied by other confounding factors (e.g. hypercapnia, polycythemia, in order to prevent or reduce its harmful consequences, while maximize its potential utility as an effective therapeutic tool in pediatric patients.

Hemorrhagic lumbar facet cysts accompanying a spinal subdural hematoma at the same level.

Science.gov (United States)

Ikeda, Osamu; Minami, Norihiko; Yamazaki, Masashi; Koda, Masao; Morinaga, Tatsuo

2015-03-01

We present a rare and interesting case of hemorrhagic lumbar facet cysts accompanying a spinal subdural hematoma at the same level suggesting a possible mechanism by which spinal subdural hematomas can arise. A 71-year-old man presented with persistent sciatic pain and intermittent claudication. Magnetic resonance imaging demonstrated a multilocular mass lesion that showed high signal intensity in both T1- and T2-weighted images, and was located both inside and outside of the spinal canal. Computed tomographic myelography showed a cap-shaped block of the dural tube at L5 and computed tomography with L5-S facet arthrography demonstrated cystic masses. The patient was diagnosed with lumbar radiculopathy caused by hemorrhagic facet cysts, and then progressed to surgical treatment. Surgery revealed that the cysts contained blood clots, and intraoperative findings that the inside of the dural tube appeared blackish and that the dural tube was tensely ballooned after removal of the cysts led us to explorative durotomy. The durotomy demonstrated concentrated old blood pooling both in the dorsal and ventral subdural space, and these spaces were subsequently drained. After surgery, his sciatic pain and intermittent claudication resolved. There was no evidence of cyst mass recurrence at 2 years of follow-up. We propose a newly described mechanism for the formation of spinal subdural hematomas. We recommend surgeons be alert to epidural lesions causing repeated acute compression of the dural tube, which can cause spinal subdural hematoma, and consider the possible coexistence of these lesions in diagnosis and strategic surgical decisions.

The prevalence of peripheral arterial disease in diabetic subjects in south-west Nigeria

Directory of Open Access Journals (Sweden)

Bolaji O. Oyelade

2012-10-01

Full Text Available Background: Peripheral arterial disease (PAD is rarely sought for and generally underdiagnosed even in diabetics in developing countries like Nigeria. PAD is easily detected and diagnosed by the ankle-brachial index, a simple and reliable test. Objectives: To determine the prevalence of PAD in diabetic subjects aged 50–89 years and the value of ankle-brachial index measurement in the detection of PAD. Method: A cross-sectional descriptive study of 219 diabetic subjects aged 50–89 years was carried out. The participants were administered a pre-tested questionnaire and measurement of ankle-brachial index (ABI was done. The ankle-brachial index < 0.90 was considered equivalent to peripheral arterial disease. Results: The overall prevalence of PAD was 52.5%. The prevalence of symptomatic PAD was 28.7% whilst that of asymptomatic PAD was 71.3%. There were a number of associations with PAD which included, age (p < 0.05, sex (p < 0.05, and marital status (p < 0.05. The use of the ankle-brachial index in the detection of PAD was clearly more reliable than the clinical methods like history of intermittent claudication and absence or presence of pedal pulses. Conclusion: The prevalence of PAD is relatively high in diabetic subjects in the southwestern region of Nigeria. Notable is the fact that a higher proportion was asymptomatic. Also the use of ABI is of great value in the detection of PAD as evidenced by a clearly more objective assessment of PAD compared to both intermittent claudication and absent pedal pulses.

Intermittent Aeration Suppresses Nitrite-Oxidizing Bacteria in Membrane-Aerated Biofilms: A Model-Based Explanation

DEFF Research Database (Denmark)

Ma, Yunjie; Domingo Felez, Carlos; Plósz, Benedek G.

2017-01-01

. On the basis of dissolved oxygen (DO), ammonium, nitrite, and nitrate profiles within the biofilm and in the bulk, a 1-dimensional nitrifying biofilm model was developed and calibrated. The model was utilized to explore the potential mechanisms of NOB suppression associated with intermittent aeration...... nitritation, strategies to suppress nitrite-oxidizing bacteria (NOB) are needed, which are ideally grounded on an understanding of underlying mechanisms. In this study, a nitrifying MABR was operated under intermittent aeration. During eight months of operation, AOB dominated, while NOB were suppressed...... during intermittent aeration was mostly explained by periodic inhibition caused by free ammonia due to periodic transient pH upshifts. Dissolved oxygen limitation did not govern NOB suppression. Different intermittent aeration strategies were then evaluated for nitritation success in intermittently...

Intermittent turbulence and oscillations in the stable boundary layer over land

NARCIS (Netherlands)

Wiel, van de B.

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

Juvenile allergic urethritis with urethro-ejaculatory reflux presenting as acute intermittent bilateral testicular torsion.

Science.gov (United States)

Patel, Ramnik V; Brimioulle, Marina; Govani, Dhaval; Youssef, Talaat

2015-07-06

We report a case of juvenile allergic urethritis secondary to double concentrate orange squash of a famous brand in a 3-year-old boy who developed bilateral urethro-ejaculatory reflux (UER) and severe urethral, perineal and scrotal pain referred to both lower limbs intermittently predominantly during and after micturition-simulating features of bilateral intermittent testicular torsion. Accurate history, urinalysis, ultrasound, colour Doppler and food challenge were helpful in diagnosis. Topical steroids, antihistaminic, analgesic and anti-inflammatory medications together with withdrawal of the allergen produced complete recovery. Allergic urethritis in association with bilateral UER causing secondary seminal vesiculitis and epididymitis is rare. It presented as acute scrotum and responded to innovative treatment. Allergic disease can have a dramatic effect on a child's quality of life. This is the first documented case of allergic urethritis and associated UER presenting as juvenile acute scrotum. Steroids, antihistamines and anti-inflammatory agents together with avoidance of the allergen helped achieve recovery. 2015 BMJ Publishing Group Ltd.

Efficient search by optimized intermittent random walks

International Nuclear Information System (INIS)

Oshanin, Gleb; Lindenberg, Katja; Wio, Horacio S; Burlatsky, Sergei

2009-01-01

We study the kinetics for the search of an immobile target by randomly moving searchers that detect it only upon encounter. The searchers perform intermittent random walks on a one-dimensional lattice. Each searcher can step on a nearest neighbor site with probability α or go off lattice with probability 1 - α to move in a random direction until it lands back on the lattice at a fixed distance L away from the departure point. Considering α and L as optimization parameters, we seek to enhance the chances of successful detection by minimizing the probability P N that the target remains undetected up to the maximal search time N. We show that even in this simple model, a number of very efficient search strategies can lead to a decrease of P N by orders of magnitude upon appropriate choices of α and L. We demonstrate that, in general, such optimal intermittent strategies are much more efficient than Brownian searches and are as efficient as search algorithms based on random walks with heavy-tailed Cauchy jump-length distributions. In addition, such intermittent strategies appear to be more advantageous than Levy-based ones in that they lead to more thorough exploration of visited regions in space and thus lend themselves to parallelization of the search processes.

Effect of Acute Intermittent CPAP Depressurization during Sleep in Obese Patients.

Science.gov (United States)

Jun, Jonathan C; Unnikrishnan, Dileep; Schneider, Hartmut; Kirkness, Jason; Schwartz, Alan R; Smith, Philip L; Polotsky, Vsevolod Y

2016-01-01

Obstructive Sleep Apnea (OSA) describes intermittent collapse of the airway during sleep, for which continuous positive airway pressure (CPAP) is often prescribed for treatment. Prior studies suggest that discontinuation of CPAP leads to a gradual, rather than immediate return of baseline severity of OSA. The objective of this study was to determine the extent of OSA recurrence during short intervals of CPAP depressurization during sleep. Nine obese (BMI = 40.4 ± 3.5) subjects with severe OSA (AHI = 88.9 ± 6.8) adherent to CPAP were studied during one night in the sleep laboratory. Nasal CPAP was delivered at therapeutic (11.1 ± 0.6 cm H20) or atmospheric pressure, in alternating fashion for 1-hour periods during the night. We compared sleep architecture and metrics of OSA during CPAP-on and CPAP-off periods. 8/9 subjects tolerated CPAP withdrawal. The average AHI during CPAP-on and CPAP-off periods was 3.6 ± 0.6 and 15.8 ± 3.6 respectively (p<0.05). The average 3% ODI during CPAP-on and CPAP-off was 4.7 ± 2 and 20.4 ± 4.7 respectively (p<0.05). CPAP depressurization also induced more awake (p<0.05) and stage N1 (p<0.01) sleep, and less stage REM (p<0.05) with a trend towards decreased stage N3 (p = 0.064). Acute intermittent depressurization of CPAP during sleep led to deterioration of sleep architecture but only partial re-emergence of OSA. These observations suggest carryover effects of CPAP.

Effect of Acute Intermittent CPAP Depressurization during Sleep in Obese Patients.

Directory of Open Access Journals (Sweden)

Jonathan C Jun

Full Text Available Obstructive Sleep Apnea (OSA describes intermittent collapse of the airway during sleep, for which continuous positive airway pressure (CPAP is often prescribed for treatment. Prior studies suggest that discontinuation of CPAP leads to a gradual, rather than immediate return of baseline severity of OSA. The objective of this study was to determine the extent of OSA recurrence during short intervals of CPAP depressurization during sleep.Nine obese (BMI = 40.4 ± 3.5 subjects with severe OSA (AHI = 88.9 ± 6.8 adherent to CPAP were studied during one night in the sleep laboratory. Nasal CPAP was delivered at therapeutic (11.1 ± 0.6 cm H20 or atmospheric pressure, in alternating fashion for 1-hour periods during the night. We compared sleep architecture and metrics of OSA during CPAP-on and CPAP-off periods.8/9 subjects tolerated CPAP withdrawal. The average AHI during CPAP-on and CPAP-off periods was 3.6 ± 0.6 and 15.8 ± 3.6 respectively (p<0.05. The average 3% ODI during CPAP-on and CPAP-off was 4.7 ± 2 and 20.4 ± 4.7 respectively (p<0.05. CPAP depressurization also induced more awake (p<0.05 and stage N1 (p<0.01 sleep, and less stage REM (p<0.05 with a trend towards decreased stage N3 (p = 0.064.Acute intermittent depressurization of CPAP during sleep led to deterioration of sleep architecture but only partial re-emergence of OSA. These observations suggest carryover effects of CPAP.

Intermittent chaotic chimeras for coupled rotators

DEFF Research Database (Denmark)

Olmi, Simona; Martens, Erik Andreas; Thutupalli, Shashi

2015-01-01

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...

Cost effectiveness of intermittent screening followed by treatment versus intermittent preventive treatment during pregnancy in West Africa

DEFF Research Database (Denmark)

Fernandes, Silke; Sicuri, Elisa; Halimatou, Diawara

2016-01-01

$/DALY averted. Simulations show that cost-effectiveness of ISTp-AL increases as the efficacy of IPTp-SP decreases, though the specific threshold at which ISTp-AL becomes cost-effective depends on assumptions about the contribution of bed nets to malaria control, bed net coverage and the willingness......-to-pay threshold used.  Conclusions: At SP efficacy levels currently observed in the trial settings it would not be cost-effective to switch from IPTp-SP to ISTp-AL, mainly due to the substantially higher costs of ISTp-AL and limited difference in outcomes. The modelling results indicate thresholds below which IPT......Background: Emergence of high-grade sulfadoxine-pyrimethamine (SP) resistance in parts of Africa has led to growing concerns about the efficacy of intermittent preventive treatment of malaria during pregnancy (IPTp) with SP. The incremental cost-effectiveness of intermittent screening and treatment...

Subcutaneous adipose tissue blood flow in the forefoot during 24 hours. Labeling pattern and reproducibility

DEFF Research Database (Denmark)

Jelnes, Rolf; Bülow, J; Tønnesen, K H

1987-01-01

Wash-out of 133xenon from a local depot in the subcutaneous adipose tissue in the forefoot was measured continuously during 24 hours on subsequent recordings in 51 feet (normal circulation: 10, intermittent claudication: 22 and ischaemic nocturnal rest pain: 19) with a mean time interval of 26 da...... was calculated to 10%, and for the ratio of blood flow from day to night to 5%. The method is thus considered apt as a monitor in the treatment of peripheral vascular disease, for example, surgery and medical therapy. As predominant source of error is the formation of oedema....

Muscular soreness following prolonged intermittent high-intensity shuttle running.

Science.gov (United States)

Thompson, D; Nicholas, C W; Williams, C

1999-05-01

The aim of this study was to examine the impact of prolonged intermittent high-intensity shuttle running on soreness and markers of muscle damage. Sixteen males took part in the study, half of whom were assigned to a running group and half to a resting control group. The exercise protocol involved 90 min of intermittent shuttle running and walking (Loughborough Intermittent Shuttle Test: LIST), reflecting the activity pattern found in multiple-sprint sports such as soccer. Immediately after exercise, there was a significant increase (P < 0.05) in serum activities of creatine kinase and aspartate aminotransferase, and values remained above baseline for 48 h (P < 0.05). Median peak activities of creatine kinase and aspartate aminotransferase occurred 24 h post-exercise and were 774 and 43 U x l(-1), respectively. The intensity of general muscle soreness, and in the specific muscles investigated, was greater than baseline for 72 h after the shuttle test (P < 0.05), peaking 24-48 h post-exercise (P < 0.05). Muscle soreness was not correlated with either creatine kinase or aspartate aminotransferase activity. Soreness was most frequently reported in the hamstrings. Neither soreness nor serum enzyme activity changed in the controls over the 4 day observation period. It appears that unaccustomed performance of prolonged intermittent shuttle running produces a significant increase in both soreness and markers of muscle damage.

Chronic intermittent hyperoxia alters the development of the hypoxic ventilatory response in neonatal rats.

Science.gov (United States)

Logan, Sarah; Tobin, Kristina E; Fallon, Sarah C; Deng, Kevin S; McDonough, Amy B; Bavis, Ryan W

2016-01-01

Chronic exposure to sustained hyperoxia alters the development of the respiratory control system, but the respiratory effects of chronic intermittent hyperoxia have rarely been investigated. We exposed newborn rats to short, repeated bouts of 30% O2 or 60% O2 (5 bouts h(-1)) for 4-15 days and then assessed their hypoxic ventilatory response (HVR; 10 min at 12% O2) by plethysmography. The HVR tended to be enhanced by intermittent hyperoxia at P4 (early phase of the HVR), but it was significantly reduced at P14-15 (primarily late phase of the HVR) compared to age-matched controls; the HVR recovered when individuals were returned to room air and re-studied as adults. To investigate the role of carotid body function in this plasticity, single-unit carotid chemoafferent activity was recorded in vitro. Intermittent hyperoxia tended to decrease spontaneous action potential frequency under normoxic conditions but, contrary to expectations, hypoxic responses were only reduced at P4 (not at P14) and only in rats exposed to higher O2 levels (i.e., intermittent 60% O2). Rats exposed to intermittent hyperoxia had smaller carotid bodies, and this morphological change may contribute to the blunted HVR. In contrast to rats exposed to intermittent hyperoxia beginning at birth, two weeks of intermittent 60% O2 had no effect on the HVR or carotid body size of rats exposed beginning at P28; therefore, intermittent hyperoxia-induced respiratory plasticity appears to be unique to development. Although both intermittent and sustained hyperoxia alter carotid body development and the HVR of rats, the specific effects and time course of this plasticity differs. Copyright © 2015 Elsevier B.V. All rights reserved.

Distinct mechanisms underlying tolerance to intermittent and constant hypoxia in Drosophila melanogaster.

Directory of Open Access Journals (Sweden)

Priti Azad

Full Text Available BACKGROUND: Constant hypoxia (CH and intermittent hypoxia (IH occur during several pathological conditions such as asthma and obstructive sleep apnea. Our research is focused on understanding the molecular mechanisms that lead to injury or adaptation to hypoxic stress using Drosophila as a model system. Our current genome-wide study is designed to investigate gene expression changes and identify protective mechanism(s in D. melanogaster after exposure to severe (1% O(2 intermittent or constant hypoxia. METHODOLOGY/PRINCIPAL FINDINGS: Our microarray analysis has identified multiple gene families that are up- or down-regulated in response to acute CH or IH. We observed distinct responses to IH and CH in gene expression that varied in the number of genes and type of gene families. We then studied the role of candidate genes (up-or down-regulated in hypoxia tolerance (adult survival for longer periods (CH-7 days, IH-10 days under severe CH or IH. Heat shock proteins up-regulation (specifically Hsp23 and Hsp70 led to a significant increase in adult survival (as compared to controls of P-element lines during CH. In contrast, during IH treatment the up-regulation of Mdr49 and l(208717 genes (P-element lines provided survival advantage over controls. This suggests that the increased transcript levels following treatment with either paradigm play an important role in tolerance to severe hypoxia. Furthermore, by over-expressing Hsp70 in specific tissues, we found that up-regulation of Hsp70 in heart and brain play critical role in tolerance to CH in flies. CONCLUSIONS/SIGNIFICANCE: We observed that the gene expression response to IH or CH is specific and paradigm-dependent. We have identified several genes Hsp23, Hsp70, CG1600, l(208717 and Mdr49 that play an important role in hypoxia tolerance whether it is in CH or IH. These data provide further clues about the mechanisms by which IH or CH lead to cell injury and morbidity or adaptation and survival.

The problem of intermittency of renewable energies: solar and wind energy

International Nuclear Information System (INIS)

Livet, Frederic

2011-01-01

As solar and wind energies are to be intensively developed but are intermittent, more or less regular and unpredictable, the author first discusses methods which are presently used to manage this intermittency in various European countries. He also discusses the various methods which are proposed to compensate this intermittency: hydraulic storage, hydrogen-based storage, batteries, and large scale interconnections. He gives and comments cost assessments of the various proposed methods and of capacities. He shows that various measures which are discussed at the European level to promote renewable energies and to promote electricity exchanges will in fact result in a three times higher price of electricity for individuals

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.

Demographics and frequency of the intermittently upturned omentum at CT

International Nuclear Information System (INIS)

Penn, Alex; Wang, Wilbur; Wang, Zhen Jane; Yee, Judy; Webb, Emily M.; Yeh, Benjamin M.

2013-01-01

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

29 CFR 825.203 - Scheduling of intermittent or reduced schedule leave.

Science.gov (United States)

2010-07-01

... leave intermittently or on a reduced leave schedule for planned medical treatment, then the employee... 29 Labor 3 2010-07-01 2010-07-01 false Scheduling of intermittent or reduced schedule leave. 825... OF LABOR OTHER LAWS THE FAMILY AND MEDICAL LEAVE ACT OF 1993 Employee Leave Entitlements Under the...

Adequacy in dialysis: intermittent versus continuous therapies.

Science.gov (United States)

Misra, M; Nolph, K D

2000-01-01

A vital conceptual difference between intermittent and continuous dialysis therapies is the difference in the relationship between Kt/V urea and dietary protein intake. For a given level of protein intake the intermittent therapies require a higher Kt/V urea due to the reasons mentioned above. The recently released adequacy guidelines by DOQI for intermittent and continuous therapies are based on these assumptions. The link between adequacy targets and patient survival is well documented for an intermittent therapy like HD. For a continuous therapy like CAPD however, the evidence linking improved peritoneal clearance to better survival is not as direct. However, present consensus allows one to extrapolate results based on HD. The concept of earlier and healthier initiation of dialysis is gaining hold and incremental dialysis forms an integral aspect of the whole concept. Tools like urea kinetic modeling give us valuable insight in making mathematical projections about the timing as well as dosing of dialysis. Daily home hemodialysis is still an underutilized modality despite offering best survival figures. Hopefully, with increasing availability of better and simpler machines its use will increase. Still several questions remain unanswered. Despite availability of data in hemodialysis patients suggesting that an increased dialysis prescription leads to a better survival, optimal dialysis dose is yet to be defined. Concerns regarding methodology of such studies and conclusions thereof has been raised. Other issues relating to design of the studies, variation in dialysis delivery, use of uncontrolled historical standards and lack of patient randomization etc also need to be considered when designing such trials. Hopefully an ongoing prospective randomized trial, namely the HEMO study, looking at two precisely defined and carefully maintained dialysis prescriptions will provide some insight into adequacy of dialysis dose and survival. In diabetic patients, the

Boldness and intermittent locomotion in the bluegill sunfish, Lepomis macrochirus

OpenAIRE

Alexander D.M. Wilson; Jean-Guy J. Godin

2009-01-01

Intermittent locomotion, characterized by moves interspersed with pauses, is a common pattern of locomotion in animals, but its ecological and evolutionary significance relative to continuous locomotion remains poorly understood. Although many studies have examined individual differences in both intermittent locomotion and boldness separately, to our knowledge, no study to date has investigated the relationship between these 2 traits. Characterizing and understanding this relationship is impo...

The intermittency of vector fields and random-number generators

Science.gov (United States)

Kalinin, A. O.; Sokoloff, D. D.; Tutubalin, V. N.

2017-09-01

We examine how well natural random-number generators can reproduce the intermittency phenomena that arise in the transfer of vector fields in random media. A generator based on the analysis of financial indices is suggested as the most promising random-number generator. Is it shown that even this generator, however, fails to reproduce the phenomenon long enough to confidently detect intermittency, while the C++ generator successfully solves this problem. We discuss the prospects of using shell models of turbulence as the desired generator.

Muscle involvement during intermittent contraction patterns with different target force feedback modes

DEFF Research Database (Denmark)

Sjøgaard, G; Jørgensen, L V; Ekner, D

2000-01-01

and following 30 min of intermittent contractions showed larger fatigue development with proprioceptive feedback than visual feedback. Also rating of perceived exertion increased more during proprioceptive feedback than visual feedback. This may in part be explained by small differences in the mechanics during......: Feedback mode significantly effects the muscle involvement and fatigue during intermittent contractions. RelevanceIntermittent contractions are common in many work places and various feedback modes are being given regarding work requirements. The choice of feedback may significantly affect the muscle load...... and consequently the development muscle fatigue and disorders....

Intermittent Hypoxia in Childhood: The Harmful Consequences Versus Potential Benefits of Therapeutic Uses

OpenAIRE

Serebrovskaya, Tatiana V.; Xi, Lei

2015-01-01

Intermittent hypoxia often occurs in early infancy in both preterm and term infants and especially at 36 to 44 weeks postmenstrual age. These episodes of intermittent hypoxia could result from sleep-disordered breathing or may be temporally unrelated to apnea or bradycardia events. There are numerous reports indicating adverse effects of intermittent hypoxia on development, behavior, academic achievement and cognition in children with sleep apnea syndrome. It remains uncertain the exact causa...

Sprint vs. intermittent training in young female basketball players.

Science.gov (United States)

Attene, G; Pizzolato, F; Calcagno, G; Ibba, G; Pinna, M; Salernitano, G; Padulo, J

2014-04-01

This study aimed at comparing the effects of intermittent and repeated sprint ability training on physiological variables. Sixteen young female basketball players were randomly allocated to intermittent training (IT=8) or repeated sprint ability training (RST=8) groups. The following outcomes were measured at baseline and after 6 weeks of training: Yo-Yo intermittent recovery (Yo-Yo) and repeated sprint ability (RSA) tests. For all the variables investigated the effect of training type showed a different trend respect at current knowledge. In the RSA, best time (BT) was a significant main effect of training time (pre- vs. post-) (Ptraining type/time (P=0.03). The RST showed a decrease in BT of 3.1% (P=0.005) while the IT showed a decrease of 6.2% (Ptraining methods used in this study can be an effective training strategy for inducing anaerobic and basketball-specific training schedules. Besides, even when IT training is not done at very high speed, it can increase the maximum speed of the RSA.

EVOLUTION OF INTERMITTENCY IN THE SLOW AND FAST SOLAR WIND BEYOND THE ECLIPTIC PLANE

International Nuclear Information System (INIS)

Wawrzaszek, A.; Macek, W. M.; Echim, M.; Bruno, R.

2015-01-01

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

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.

Intermittent operation of ultra-low pressure ultrafiltration for decentralized drinking water treatment.

Science.gov (United States)

Peter-Varbanets, Maryna; Gujer, Willi; Pronk, Wouter

2012-06-15

River water was treated by ultrafiltration at a relatively low transmembrane pressure (40 mbar). As observed before, flux stabilization occurred after several days of operation although no back-flushing or cross flow was applied. Interruptions in flux were applied by temporary offset of the transmembrane pressure. After restoration of the transmembrane pressure, the initial flux was higher than the stable flux level, and the flux recovery depended on the standstill time. Furthermore, if a short cross flow was applied after standstill, the flux was restored to an even higher level. In all cases, the flux decreased again during operation to reach finally the same stable level as before standstill. In order to evaluate the influence of intermittent operation as practiced for water treatment on a household level, daily interruptions of flux were applied. An optimum of total daily water production rate was obtained at 21 h of operation and 3 h of standstill per day. A model was developed which can describe the impact of intermittent operation on the flux depending on the duration of the standstill and operating periods. This enables the prediction of production capacity of the system operated intermittently. The flux increase during standstill could be explained by a relaxation and expansion of the biofouling layer, while the higher flux after forward-flushing was caused by this layer being partially sloughed off. Household water treatment with the process presented here will generally be operated on a discontinuous basis. The results show that such operation schemes do not compromise the permeability of the system, but actually lead to higher fluxes after standstill. Copyright © 2012 Elsevier Ltd. All rights reserved.

Economic intermittency in a two-country model of business cycles coupled by investment

Energy Technology Data Exchange (ETDEWEB)

Saiki, Y., E-mail: saiki@math.sci.hokudai.ac.jp [Department of Mathematics, Hokkaido University, Sapporo 060-0810 (Japan); Chian, A.C.L. [National Institute for Space Research (INPE) and World Institute for Space Environment Research (WISER), P.O. Box 515, Sao Jose dos Campos-SP 12227-010 (Brazil); California Institute of Technology, Pasadena, CA 91125 (United States); Yoshida, H. [College of Economics, Nihon University, Tokyo 101-8360 (Japan)

2011-06-15

Highlights: > Intermittent economic behavior of Keynes-Goodwin type model is investigated. > After a transition the system keeps its memory before the transition. > The intermittent phenomena is examined from the business cycle patterns. > It is concluded that dynamical patterns do not alter much around the transition. - Abstract: Intermittent behavior of economic dynamics is investigated by a two-country model of Keynes-Goodwin type business cycles. Numerical simulations show that after an economic system evolves from weak chaos to strong chaos the system keeps its memory before the transition and its time series alternates episodically between periods of weakly and strongly chaotic fluctuations. In addition, we examine the intermittent phenomena from the view point of business cycle patterns near the crisis point.

Economic intermittency in a two-country model of business cycles coupled by investment

International Nuclear Information System (INIS)

Saiki, Y.; Chian, A.C.L.; Yoshida, H.

2011-01-01

Highlights: → Intermittent economic behavior of Keynes-Goodwin type model is investigated. → After a transition the system keeps its memory before the transition. → The intermittent phenomena is examined from the business cycle patterns. → It is concluded that dynamical patterns do not alter much around the transition. - Abstract: Intermittent behavior of economic dynamics is investigated by a two-country model of Keynes-Goodwin type business cycles. Numerical simulations show that after an economic system evolves from weak chaos to strong chaos the system keeps its memory before the transition and its time series alternates episodically between periods of weakly and strongly chaotic fluctuations. In addition, we examine the intermittent phenomena from the view point of business cycle patterns near the crisis point.

Pinning synchronization of hybrid-coupled directed delayed dynamical network via intermittent control.

Science.gov (United States)

Cai, Shuiming; Zhou, Peipei; Liu, Zengrong

2014-09-01

This paper concerns the problem of exponential synchronization for a class of general delayed dynamical networks with hybrid coupling via pinning periodically intermittent control. Both the internal delay and coupling delay are taken into account in the network model. Meanwhile, the transmission delay and self-feedback delay are involved in the delayed coupling term. By establishing a new differential inequality, several simple and useful exponential synchronization criteria are derived analytically. It is shown that the controlled synchronization state can vary in comparison with the conventional synchronized solution, and the degree of the node and the inner delayed coupling matrix play important roles in the controlled synchronization state. By choosing different inner delayed coupling matrices and the degrees of the node, different controlled synchronization states can be obtained. Furthermore, the detail pinning schemes deciding what nodes should be chosen as pinned candidates and how many nodes are needed to be pinned for a fixed coupling strength are provided. The simple procedures illuminating how to design suitable intermittent controllers in real application are also given. Numerical simulations, including an undirected scale-free network and a directed small-world network, are finally presented to demonstrate the effectiveness of the theoretical results.

Intermittent characteristics in coupling between turbulence and zonal flows

International Nuclear Information System (INIS)

Fujisawa, A; Shimizu, A; Nakano, H; Ohshima, S; Itoh, K; Nagashima, Y; Itoh, S-I; Iguchi, H; Yoshimura, Y; Minami, T; Nagaoka, K; Takahashi, C; Kojima, M; Nishimura, S; Isobe, M; Suzuki, C; Akiyama, T; Ido, T; Matsuoka, K; Okamura, S; Diamond, P H

2007-01-01

An extended application of Gabour's wavelet to bicoherence analysis succeeds in resolving the instantaneous structure of three wave couplings between disparate scale electric field fluctuations in the high temperature core in a toroidal plasma device named the compact helical system. The obtained results quantify an intermittent linkage between turbulence and zonal flows-a highlighted issue in the present plasma research. This is the first demonstration that the intermittent nature of the three wave coupling should underlie the turbulence power modulation due to zonal flows

Effects of Intermittent Versus Continuous Walking on Distance Walked and Fatigue in Persons With Multiple Sclerosis: A Randomized Crossover Trial.

Science.gov (United States)

Karpatkin, Herb; Cohen, Evan T; Rzetelny, Adam; Parrott, J Scott; Breismeister, Breanne; Hartman, Ryan; Luu, Ronald; Napolione, Danielle

2015-07-01

Fatigue is a common, disabling symptom experienced by persons with multiple sclerosis (MS). Evidence shows that intermittent exercise is associated in improved performance and negligible fatigue. The purpose of this study was to examine whether subjects with MS walk greater distances with less fatigue under intermittent (INT) or continuous (CONT) walking condition. Twenty-seven subjects with MS (median Extended Disability Severity Scale 3.5, interquartile range 1.6) walked in the CONT (ie, 6 uninterrupted minutes) and INT (ie, three 2-minute walking bouts) conditions in a randomized crossover. Distance was measured for the entire 6-minute walking period and each 2-minute increment. Fatigue was measured as the difference in a visual analog scale of fatigue (ΔVAS-F) immediately preceding and following each trial. Participants walked greater distances in the INT condition compared to the CONT condition (P = 0.005). There was a significant interaction of walking condition and time (P walked in the INT condition changed across time. ΔVAS-F was significantly lower in the INT condition than in the CONT condition (P = 0.036). Subjects with MS walked farther, and with less fatigue, when walking intermittently rather than continuously. Persons with MS may be able to tolerate a greater dose of walking training if the walking bouts are intermittent. Further study to determine the benefits of a walking exercise program using intermittent walking is recommended.Video Abstract available for additional insights from the authors (Supplemental Digital Content 1, http://links.lww.com/JNPT/A103).

The stochastic dynamics of intermittent porescale particle motion

Science.gov (United States)

Dentz, Marco; Morales, Veronica; Puyguiraud, Alexandre; Gouze, Philippe; Willmann, Matthias; Holzner, Markus

2017-04-01

Numerical and experimental data for porescale particle dynamics show intermittent patterns in Lagrangian velocities and accelerations, which manifest in long time intervals of low and short durations of high velocities [1, 2]. This phenomenon is due to the spatial persistence of particle velocities on characteristic heterogeneity length scales. In order to systematically quantify these behaviors and extract the stochastic dynamics of particle motion, we focus on the analysis of Lagrangian velocities sampled equidistantly along trajectories [3]. This method removes the intermittency observed under isochrone sampling. The space-Lagrangian velocity series can be quantified by a Markov process that is continuous in distance along streamline. It is fully parameterized in terms of the flux-weighted Eulerian velocity PDF and the characteristic pore-length. The resulting stochastic particle motion describes a continuous time random walk (CTRW). This approach allows for the process based interpretation of experimental and numerical porescale velocity, acceleration and displacement data. It provides a framework for the characterization and upscaling of particle transport and dispersion from the pore to the Darcy-scale based on the medium geometry and Eulerian flow attributes. [1] P. De Anna, T. Le Borgne, M. Dentz, A.M. Tartakovsky, D. Bolster, and P. Davy, "Flow intermittency, dispersion, and correlated continuous time random walks in porous media," Phys. Rev. Lett. 110, 184502 (2013). [2] M. Holzner, V. L. Morales, M. Willmann, and M. Dentz, "Intermittent Lagrangian velocities and accelerations in three- dimensional porous medium flow," Phys. Rev. E 92, 013015 (2015). [3] M. Dentz, P. K. Kang, A. Comolli, T. Le Borgne, and D. R. Lester, "Continuous time random walks for the evolution of Lagrangian velocities," Phys. Rev. Fluids (2016).

Circulating, cell-free DNA as a marker for exercise load in intermittent sports

OpenAIRE

Haller, Nils; Helmig, Susanne; Taenny, Pascal; Petry, Julian; Schmidt, Sebastian; Simon, Perikles

2018-01-01

Background Attempts to establish a biomarker reflecting individual player load in intermittent sports such as football have failed so far. Increases in circulating DNA (cfDNA) have been demonstrated in various endurance sports settings. While it has been proposed that cfDNA could be a suitable marker for player load in intermittent sports, the effects on cfDNA of repeated sprinting as an essential feature in intermittent sports are unknown. For the first time, we assessed both alterations of ...

Intermittent dynamics of nonlinear resistive tearing modes at extremely high magnetic Reynolds number

International Nuclear Information System (INIS)

Miyoshi, Takahiro; Becchaku, Masahiro; Kusano, Kanya

2008-01-01

Nonlinear dynamics of the resistive tearing instability in high magnetic Reynolds number (R m ) plasmas is studied by newly developing an accurate and robust resistive magnetohydrodynamic (MHD) scheme. The results show that reconnection processes strongly depend on R m . Particularly, in a high R m case, small-scale plasmoids induced by a secondary instability are intermittently generated and ejected accompanied by fast shocks. According to the intermittent processes, the reconnection rate increases intermittently at a later nonlinear stage. (author)

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.

Chronic intermittent hypoxia preserves bone density in a mouse model of sleep apnea.

Science.gov (United States)

Torres, Marta; Montserrat, Josep M; Pavía, Javier; Dalmases, Mireia; Ros, Domenec; Fernandez, Yolanda; Barbé, Ferran; Navajas, Daniel; Farré, Ramon

2013-12-01

Very recent clinical research has investigated whether obstructive sleep apnea (OSA) may modulate bone homeostasis but the few data available are conflicting. Here we report novel data obtained in a mouse study specifically designed to determine whether chronic intermittent hypoxia realistically mimicking OSA modifies bone mineral density (BMD). Normal male and female mice and orchidectomized mice (N=10 each group) were subjected to a pattern of high-frequency intermittent hypoxia (20s at 5% and 40s at 21%, 60 cycles/h) for 6h/day. Identical groups breathing room air (normoxia) were the controls. After 32 days of intermittent hypoxia/normoxia the trabecular bone mineral density (BMD) in the peripheral femora were measured by micro-CT scanning. When compared with normoxia (two-way ANOVA), intermittent hypoxia did not significantly modify BMD in the three animal groups tested. Data in this study suggest that the type of intermittent hypoxia characterizing OSA, applied as a single challenge, preserves bone homeostasis. Copyright © 2013 Elsevier B.V. All rights reserved.

External intermittency prediction using AMR solutions of RANS turbulence and transported PDF models

Science.gov (United States)

Olivieri, D. A.; Fairweather, M.; Falle, S. A. E. G.

2011-12-01

External intermittency in turbulent round jets is predicted using a Reynolds-averaged Navier-Stokes modelling approach coupled to solutions of the transported probability density function (pdf) equation for scalar variables. Solutions to the descriptive equations are obtained using a finite-volume method, combined with an adaptive mesh refinement algorithm, applied in both physical and compositional space. This method contrasts with conventional approaches to solving the transported pdf equation which generally employ Monte Carlo techniques. Intermittency-modified eddy viscosity and second-moment turbulence closures are used to accommodate the effects of intermittency on the flow field, with the influence of intermittency also included, through modifications to the mixing model, in the transported pdf equation. Predictions of the overall model are compared with experimental data on the velocity and scalar fields in a round jet, as well as against measurements of intermittency profiles and scalar pdfs in a number of flows, with good agreement obtained. For the cases considered, predictions based on the second-moment turbulence closure are clearly superior, although both turbulence models give realistic predictions of the bimodal scalar pdfs observed experimentally.

Quasistatic Dynamics with Intermittency

International Nuclear Information System (INIS)

Leppänen, Juho; Stenlund, Mikko

2016-01-01

We study an intermittent quasistatic dynamical system composed of nonuniformly hyperbolic Pomeau–Manneville maps with time-dependent parameters. We prove an ergodic theorem which shows almost sure convergence of time averages in a certain parameter range, and identify the unique physical family of measures. The theorem also shows convergence in probability in a larger parameter range. In the process, we establish other results that will be useful for further analysis of the statistical properties of the model.

Quasistatic Dynamics with Intermittency

Energy Technology Data Exchange (ETDEWEB)

Leppänen, Juho; Stenlund, Mikko, E-mail: mikko.stenlund@helsinki.fi [University of Helsinki, Department of Mathematics and Statistics (Finland)

2016-06-15

We study an intermittent quasistatic dynamical system composed of nonuniformly hyperbolic Pomeau–Manneville maps with time-dependent parameters. We prove an ergodic theorem which shows almost sure convergence of time averages in a certain parameter range, and identify the unique physical family of measures. The theorem also shows convergence in probability in a larger parameter range. In the process, we establish other results that will be useful for further analysis of the statistical properties of the model.

Dealing with uncertainty in modeling intermittent water supply

Science.gov (United States)

Lieb, A. M.; Rycroft, C.; Wilkening, J.

2015-12-01

Intermittency in urban water supply affects hundreds of millions of people in cities around the world, impacting water quality and infrastructure. Building on previous work to dynamically model the transient flows in water distribution networks undergoing frequent filling and emptying, we now consider the hydraulic implications of uncertain input data. Water distribution networks undergoing intermittent supply are often poorly mapped, and household metering frequently ranges from patchy to nonexistent. In the face of uncertain pipe material, pipe slope, network connectivity, and outflow, we investigate how uncertainty affects dynamical modeling results. We furthermore identify which parameters exert the greatest influence on uncertainty, helping to prioritize data collection.

[Study on intermittent hypoxia in children sleep apnea hypopnea syndrome model and insulin-like growth factor-1 and insulin-like growth factor binding protein-3 levels in serum].

Science.gov (United States)

Hou, Jin; Yan, Jing; Kang, Quan-qing

2012-03-01

Using rats fed in intermittent hypoxia environment to study the relationship between sleep apnea hypopnea syndrome (SAHS) of children and growth retardation. The hypoxic chamber was designed and manufactured, the control of intermittent hypoxia was achieved. Twenty-four rats were randomly divided into three groups: mild and severe hypoxia group, and control group. In control group, the animals were normally fed, without interruption. The animals in other two groups were kept in the cabin, simulated mild and severe intermittent hypoxia conditions 8-hour a day, a total of 35 days. According to the results of preliminary experiments, the concentration of intermittent hypoxia and frequency were determined. The animals with mild hypoxia events occurred nearly six times per hour, the average minimum oxygen saturation dropped to 0.853, the animals with severe hypoxia events occurred nearly 24 times per hour, the average minimum oxygen saturation dropped to 0.776. Body mass and length were measured before and after experiment. The serum insulin-like growth factor (IGF)-1 and insulin-like growth factor binding protein (IGFBP)-3 expression were tested from venous blood by enzyme-linked immunosorbent assay (ELISA). The length and body mass of rats in three groups before and after experiment were not statistically different (P>0.05). Before the experiment the serum IGF-1 and IGFBP-3 levels were not significantly different (P>0.05). 35 d after the experiment, the serum IGF-1 (x±s, the same below) in the control group, mild hypoxia and severe hypoxia were (60.0±18.5) ng/ml, (40.6±9.9) ng/ml and (13.1±8.6) ng/ml, F=25.840, Phypoxia increased (Papnea hypopnea syndrome, the intermittent hypoxia in young rats does not show physical growth retardation, but the serum IGF-1, IGFBP-3 levels decreased with the increase of hypoxia and decline of oxygen saturation.

Optimal Integration of Intermittent Renewables: A System LCOE Stochastic Approach

Directory of Open Access Journals (Sweden)

Carlo Lucheroni

2018-03-01

Full Text Available We propose a system level approach to value the impact on costs of the integration of intermittent renewable generation in a power system, based on expected breakeven cost and breakeven cost risk. To do this, we carefully reconsider the definition of Levelized Cost of Electricity (LCOE when extended to non-dispatchable generation, by examining extra costs and gains originated by the costly management of random power injections. We are thus lead to define a ‘system LCOE’ as a system dependent LCOE that takes properly into account intermittent generation. In order to include breakeven cost risk we further extend this deterministic approach to a stochastic setting, by introducing a ‘stochastic system LCOE’. This extension allows us to discuss the optimal integration of intermittent renewables from a broad, system level point of view. This paper thus aims to provide power producers and policy makers with a new methodological scheme, still based on the LCOE but which updates this valuation technique to current energy system configurations characterized by a large share of non-dispatchable production. Quantifying and optimizing the impact of intermittent renewables integration on power system costs, risk and CO 2 emissions, the proposed methodology can be used as powerful tool of analysis for assessing environmental and energy policies.

Analyzing the Efficiency of Introduction of the Intermittent Heating Mode

Science.gov (United States)

Anisimova, E.; Shcherbak, A.

2017-11-01

The efficiency of introduction of an optimal intermittent heating mode for a service center building in Chelyabinsk is estimated. The optimal intermittent heating mode ensures heat energy saving while maintaining the required microclimate parameters. The graphical dependencies of the amount of heat energy saving on the heat retention of the building and the outdoor air temperature are shown. The fundamental formulas which were the basis for calculating the periods of cooling, warming and expenditures of heat energy for the two heating modes are given. The literature on the issue is reviewed, the main points, advantages and disadvantages in the works of both Russian and foreign authors are revealed. The calculation was carried out in compliance with the modern state standards and regulatory documents. The capital costs of a system construction with an intermittent heating mode are determined.

Male fertility is reduced by chronic intermittent hypoxia mimicking sleep apnea in mice.

Science.gov (United States)

Torres, Marta; Laguna-Barraza, Ricardo; Dalmases, Mireia; Calle, Alexandra; Pericuesta, Eva; Montserrat, Josep M; Navajas, Daniel; Gutierrez-Adan, Alfonso; Farré, Ramon

2014-11-01

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxia and oxidative stress. However, it is unknown whether intermittent hypoxia mimicking OSA modifies male fertility. We tested the hypothesis that male fertility is reduced by chronic intermittent hypoxia mimicking OSA in a mouse model. Case-control comparison in a murine model. University research laboratory. Eighteen F1 (C57BL/6xCBA) male mice. Mice were subjected to a pattern of periodic hypoxia (20 sec at 5% O2 followed by 40 sec of room air) 6 h/day for 60 days or normoxia. After this period, mice performed a mating trial to determine effective fertility by assessing the number of pregnant females and fetuses. After euthanasia, oxidative stress in testes was assessed by measuring the expression of glutathione peroxidase 1 (Gpx1) and superoxide dismutase-1 (Sod1) by reverse-transcription polymerase chain reaction. Sperm motility was determined by Integrated Semen Analysis System (ISAS). Intermittent hypoxia significantly increased testicular oxidative stress, showing a reduction in the expression of Gpx1 and Sod1 by 38.9% and 34.4%, respectively, as compared with normoxia (P intermittent hypoxia group (P = 0.04). The proportion of pregnant females and number of fetuses per mating was significantly lower in the intermittent hypoxia group (0.33 ± 0.10 and 2.45 ± 0.73, respectively) than in normoxic controls (0.72 ± 0.16 and 5.80 ± 1.24, respectively). These results suggest that the intermittent hypoxia associated with obstructive sleep apnea (OSA) could induce fertility reduction in male patients with this sleep breathing disorder.

Cooling tower modification for intermittent operation

International Nuclear Information System (INIS)

Midkiff, W.S.

1975-03-01

One of the cooling towers at Los Alamos Scientific Laboratory is being operated intermittently. The cooling tower has been modified to restrict air flow and to keep the tower from drying out. The modifications are relatively inexpensive, simple to operate, and have proved effective. (U.S.)

Multi-scale magnetic field intermittence in the plasma sheet

Directory of Open Access Journals (Sweden)

Z. Vörös

2003-09-01

Full Text Available This paper demonstrates that intermittent magnetic field fluctuations in the plasma sheet exhibit transitory, localized, and multi-scale features. We propose a multifractal-based algorithm, which quantifies intermittence on the basis of the statistical distribution of the "strength of burstiness", estimated within a sliding window. Interesting multi-scale phenomena observed by the Cluster spacecraft include large-scale motion of the current sheet and bursty bulk flow associated turbulence, interpreted as a cross-scale coupling (CSC process.Key words. Magnetospheric physics (magnetotail; plasma sheet – Space plasma physics (turbulence

Optimal intermittent search strategies: smelling the prey

International Nuclear Information System (INIS)

Revelli, J A; Wio, H S; Rojo, F; Budde, C E

2010-01-01

We study the kinetics of the search of a single fixed target by a searcher/walker that performs an intermittent random walk, characterized by different states of motion. In addition, we assume that the walker has the ability to detect the scent left by the prey/target in its surroundings. Our results, in agreement with intuition, indicate that the prey's survival probability could be strongly reduced (increased) if the predator is attracted (or repelled) by the trace left by the prey. We have also found that, for a positive trace (the predator is guided towards the prey), increasing the inhomogeneity's size reduces the prey's survival probability, while the optimal value of α (the parameter that regulates intermittency) ceases to exist. The agreement between theory and numerical simulations is excellent.

Optimal intermittent search strategies: smelling the prey

Energy Technology Data Exchange (ETDEWEB)

Revelli, J A; Wio, H S [Instituto de Fisica de Cantabria, Universidad de Cantabria and CSIC, E-39005 Santander (Spain); Rojo, F; Budde, C E [Fa.M.A.F., Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina)

2010-05-14

We study the kinetics of the search of a single fixed target by a searcher/walker that performs an intermittent random walk, characterized by different states of motion. In addition, we assume that the walker has the ability to detect the scent left by the prey/target in its surroundings. Our results, in agreement with intuition, indicate that the prey's survival probability could be strongly reduced (increased) if the predator is attracted (or repelled) by the trace left by the prey. We have also found that, for a positive trace (the predator is guided towards the prey), increasing the inhomogeneity's size reduces the prey's survival probability, while the optimal value of {alpha} (the parameter that regulates intermittency) ceases to exist. The agreement between theory and numerical simulations is excellent.

Feigenbaum attractor and intermittency in particle collisions

International Nuclear Information System (INIS)

Batunin, A.V.

1992-01-01

The hypothesis is proposed that the Feigenbaum attractor arising as a limit set in an infinite pichfork bifurcation sequence for unimodal one-dimensional maps underlies the intermittency phenomena in particle collisions. 23 refs.; 8 figs

Circuit implementation and multiform intermittency in a hyper-chaotic model extended from the Lorenz system

International Nuclear Information System (INIS)

Shi-Jian, Cang; Zeng-Qiang, Chen; Wen-Juan, Wu

2009-01-01

This paper presents a non-autonomous hyper-chaotic system, which is formed by adding a periodic driving signal to a four-dimensional chaotic model extended from the Lorenz system. The resulting non-autonomous hyper-chaotic system can display any dynamic behaviour among the periodic orbits, intermittency, chaos and hyper-chaos by controlling the frequency of the periodic signal. The phenomenon has been well demonstrated by numerical simulations, bifurcation analysis and electronic circuit realization. Moreover, the system is concrete evidence for the presence of Pomeau–Manneville Type-I intermittency and crisis-induced intermittency. The emergence of a different type of intermittency is similarly subjected to the frequency of periodic forcing. By statistical analysis, power scaling laws consisting in different intermittency are obtained for the lifetime in the laminar state between burst states

Hippocampal mitogen-activated protein kinase activation is associated with intermittent hypoxia in a rat model of obstructive sleep apnea syndrome.

Science.gov (United States)

Zhao, Ya-Ning; Wang, Hong-Yang; Li, Jian-Min; Chen, Bao-Yuan; Xia, Guo; Zhang, Pan-Pan; Ge, Yan-Lei

2016-01-01

generally increased at the late stages under continued hypoxia, but increased at all time-points under the intermittent hypoxia conditions. The two types of hypoxia induced an increase in the MDA content, but a decrease in SOD activity. Marked changes in these two parameters coupled with markedly reduced surviving cells in the hippocampus in a time‑dependent manner were observed in the intermittent hypoxia group in comparison with the continued hypoxia group. OSAS‑induced intermittent hypoxia markedly activated the MAPK signaling pathways, which were triggered by oxidative stress, leading to abnormal expression of downstream Bcl‑2 and Bax, and a severe loss of neural cells in the hippocampus.

Influence of Peripheral Artery Disease and Statin Therapy on Apolipoprotein Profiles

Directory of Open Access Journals (Sweden)

Andrew W. Gardner

2013-01-01

Full Text Available Apolipoprotein B is a stronger predictor of myocardial infarction than LDL cholesterol, and it is inversely related to physical activity and modifiable with exercise training. As such, apolipoprotein measures may be of particular relevance for subjects with PAD and claudication. We compared plasma apolipoprotein profiles in 29 subjects with peripheral artery disease (PAD and intermittent claudication and in 39 control subjects. Furthermore, we compared the plasma apolipoprotein profiles of subjects with PAD either treated (n=17 or untreated (n=12 with statin medications. For the apolipoprotein subparticle analyses, subjects with PAD had higher age-adjusted Lp-B:C (P<0.05 and lower values of Lp-A-I:A-II (P<0.05 than controls. The PAD group taking statins had lower age-adjusted values for apoB (P<0.05, Lp-A-II:B:C:D:E (P<0.05, Lp-B:E + Lp-B:C:E (P<0.05, Lp-B:C (P<0.05, and Lp-A-I (P<0.05 than the untreated PAD group. Subjects with PAD have impaired apolipoprotein profiles than controls, characterized by Lp-B:C and Lp-A-I:A-II. Furthermore, subjects with PAD on statin medications have a more favorable risk profile, particularly noted in multiple apolipoprotein subparticles. The efficacy of statin therapy to improve cardiovascular risk appears more evident in the apolipoprotein sub-particle profile than in the more traditional lipid profile of subjects with PAD and claudication. This trial is registered with ClinicalTrials.gov NCT00618670.

Intermittent Auscultation for Intrapartum Fetal Heart Rate Surveillance: American College of Nurse-Midwives.

Science.gov (United States)

2015-01-01

Fetal heart rate surveillance is a standard component of intrapartum care. The fetal heart rate can be evaluated using intermittent auscultation or electronic fetal monitoring. Research that has compared these 2 strategies found them to be equivalent with respect to long-term neonatal outcomes. The purpose of this clinical bulletin by the American College of Nurse-Midwives is to review the evidence for use of intermittent auscultation and provide recommendations for intermittent auscultation technique, interpretation, and documentation. © 2015 by the American College of Nurse-Midwives.

Modelling the influence of intermittent rain events on long-term fate and transport of organic air pollutants

DEFF Research Database (Denmark)

Jolliet, Olivier; Hauschild, Michael Zwicky

2005-01-01

through wet deposition, and an underestimation of travel distances, leading to the following questions: How strong is the influence of the intermittent character of rain on concentrations, residence times, deposited fractions and characteristic transport distances of different substances in air......The deposition of particles and substances in air is under strong influence of the precipitation patterns of the atmosphere. Most multimedia models, like type III Mackay models, treat rain as a continuous phenomenon. This may cause severe overestimation of the substance removal from the atmosphere......? Is there an expression which can provide an accurate approximation to be used in steady state multimedia models? Assuming a periodically intermittent rain, the mass of an emitted substance which is present in the air compartment is calculated as a function of the deposition rate constants during dry and wet periods...

Hovering and intermittent flight in birds

International Nuclear Information System (INIS)

Tobalske, Bret W

2010-01-01

Two styles of bird locomotion, hovering and intermittent flight, have great potential to inform future development of autonomous flying vehicles. Hummingbirds are the smallest flying vertebrates, and they are the only birds that can sustain hovering. Their ability to hover is due to their small size, high wingbeat frequency, relatively large margin of mass-specific power available for flight and a suite of anatomical features that include proportionally massive major flight muscles (pectoralis and supracoracoideus) and wing anatomy that enables them to leave their wings extended yet turned over (supinated) during upstroke so that they can generate lift to support their weight. Hummingbirds generate three times more lift during downstroke compared with upstroke, with the disparity due to wing twist during upstroke. Much like insects, hummingbirds exploit unsteady mechanisms during hovering including delayed stall during wing translation that is manifest as a leading-edge vortex (LEV) on the wing and rotational circulation at the end of each half stroke. Intermittent flight is common in small- and medium-sized birds and consists of pauses during which the wings are flexed (bound) or extended (glide). Flap-bounding appears to be an energy-saving style when flying relatively fast, with the production of lift by the body and tail critical to this saving. Flap-gliding is thought to be less costly than continuous flapping during flight at most speeds. Some species are known to shift from flap-gliding at slow speeds to flap-bounding at fast speeds, but there is an upper size limit for the ability to bound (∼0.3 kg) and small birds with rounded wings do not use intermittent glides.

Hovering and intermittent flight in birds

Energy Technology Data Exchange (ETDEWEB)

Tobalske, Bret W, E-mail: bret.tobalske@mso.umt.ed [Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, MT 59812 (United States)

2010-12-15

Two styles of bird locomotion, hovering and intermittent flight, have great potential to inform future development of autonomous flying vehicles. Hummingbirds are the smallest flying vertebrates, and they are the only birds that can sustain hovering. Their ability to hover is due to their small size, high wingbeat frequency, relatively large margin of mass-specific power available for flight and a suite of anatomical features that include proportionally massive major flight muscles (pectoralis and supracoracoideus) and wing anatomy that enables them to leave their wings extended yet turned over (supinated) during upstroke so that they can generate lift to support their weight. Hummingbirds generate three times more lift during downstroke compared with upstroke, with the disparity due to wing twist during upstroke. Much like insects, hummingbirds exploit unsteady mechanisms during hovering including delayed stall during wing translation that is manifest as a leading-edge vortex (LEV) on the wing and rotational circulation at the end of each half stroke. Intermittent flight is common in small- and medium-sized birds and consists of pauses during which the wings are flexed (bound) or extended (glide). Flap-bounding appears to be an energy-saving style when flying relatively fast, with the production of lift by the body and tail critical to this saving. Flap-gliding is thought to be less costly than continuous flapping during flight at most speeds. Some species are known to shift from flap-gliding at slow speeds to flap-bounding at fast speeds, but there is an upper size limit for the ability to bound ({approx}0.3 kg) and small birds with rounded wings do not use intermittent glides.

Intermittent fasting during Ramadan: does it affect sleep?

Science.gov (United States)

Bahammam, Ahmed S; Almushailhi, Khalid; Pandi-Perumal, Seithikurippu R; Sharif, Munir M

2014-02-01

Islamic intermittent fasting is distinct from regular voluntary or experimental fasting. We hypothesised that if a regimen of a fixed sleep-wake schedule and a fixed caloric intake is followed during intermittent fasting, the effects of fasting on sleep architecture and daytime sleepiness will be minimal. Therefore, we designed this study to objectively assess the effects of Islamic intermittent fasting on sleep architecture and daytime sleepiness. Eight healthy volunteers reported to the Sleep Disorders Centre on five occasions for polysomnography and multiple sleep latency tests: (1) during adaptation; (2) 3 weeks before Ramadan, after having performed Islamic fasting for 1 week (baseline fasting); (3) 1 week before Ramadan (non-fasting baseline); (4) 2 weeks into Ramadan (Ramadan); and (5) 2 weeks after Ramadan (non-fasting; Recovery). Daytime sleepiness was assessed using the Epworth Sleepiness Scale and the multiple sleep latency test. The participants had a mean age of 26.6 ± 4.9 years, a body mass index of 23.7 ± 3.5 kg m(-2) and an Epworth Sleepiness Scale score of 7.3 ± 2.7. There was no change in weight or the Epworth Sleepiness Scale in the four study periods. The rapid eye movement sleep percentage was significantly lower during fasting. There was no difference in sleep latency, non-rapid eye movement sleep percentage, arousal index and sleep efficiency. The multiple sleep latency test analysis revealed no difference in the sleep latency between the 'non-fasting baseline', 'baseline fasting', 'Ramadan' and 'Recovery' time points. Under conditions of a fixed sleep-wake schedule and a fixed caloric intake, Islamic intermittent fasting results in decreased rapid eye movement sleep with no impact on other sleep stages, the arousal index or daytime sleepiness. © 2013 European Sleep Research Society.

Intermittent negative pressure wound therapy with instillation for the treatment of persistent periprosthetic hip infections: a report of two cases

Directory of Open Access Journals (Sweden)

Söylemez MS

2016-02-01

Full Text Available Mehmet Salih Söylemez,1 Korhan Özkan,2 Bülent Kılıç,3 Samet Erinç41Department of Orthopaedics and Traumatology, Bingöl State Hospital, Bingöl, 2Department of Orthopaedics and Traumatology, Faculty of Medicine, Medeniyet University, Istanbul, 3Department of Orthopaedics and Traumatology, Orthopaedic Surgery Clinic, Istanbul Gelişim University, Tekirdağ, 4Department of Orthopaedics and Traumatology, Istanbul Medeniyet University, Göztepe Training and Research Hospital, Istanbul, TurkeyAbstract: Intermittent negative pressure wound therapy with instillation (NPWTi is starting to be used successfully to treat early periprosthetic infections of endoprostheses. However, few articles have reported the outcome of treatment with intermittent NPWTi for late persistent periprosthetic infections of the hip. In this study, we report two cases who underwent several rounds of radical wound debridement for the treatment of a late persistent periprosthetic infection of the hip. Intermittent NPWTi was used in both cases. Patients were treated successfully and there was no recurrence after 3 and 1 years of follow-up, respectively.Keywords: negative pressure, vacuum-assisted, periprosthetic infection, hip

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.

Effects of chronic pollution and water flow intermittency on stream biofilms biodegradation capacity.

Science.gov (United States)

Rožman, Marko; Acuña, Vicenç; Petrović, Mira

2018-02-01

A mesocosm case study was conducted to gain understanding and practical knowledge on biofilm emerging contaminants biodegradation capacity under stressor and multiple stressor conditions. Two real life scenarios: I) biodegradation in a pristine intermittent stream experiencing acute pollution and II) biodegradation in a chronically polluted intermittent stream, were examined via a multifactorial experiment using an artificial stream facility. Stream biofilms were exposed to different water flow conditions i.e. permanent and intermittent water flow. Venlafaxine, a readily biodegradable pharmaceutical was used as a measure of biodegradation capacity while pollution was simulated by a mixture of four emerging contaminants (erythromycin, sulfisoxazole, diclofenac and imidacloprid in addition to venlafaxine) in environmentally relevant concentrations. Biodegradation kinetics monitored via LC-MS/MS was established, statistically evaluated, and used to link biodegradation with stress events. The results suggest that the effects of intermittent flow do not hinder and may even stimulate pristine biofilm biodegradation capacity. Chronic pollution completely reduced biodegradation in permanent water flow experimental treatments while no change in intermittent streams was observed. A combined effect of water flow conditions and emerging contaminants exposure on biodegradation was found. The decrease in biodegradation due to exposure to emerging contaminants is significantly greater in streams with permanent water flow suggesting that the short and medium term biodegradation capacity in intermittent systems may be preserved or even greater than in perennial streams. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of intermittent feedback control on robustness of human-like postural control system

Science.gov (United States)

Tanabe, Hiroko; Fujii, Keisuke; Suzuki, Yasuyuki; Kouzaki, Motoki

2016-03-01

Humans have to acquire postural robustness to maintain stability against internal and external perturbations. Human standing has been recently modelled using an intermittent feedback control. However, the causality inside of the closed-loop postural control system associated with the neural control strategy is still unknown. Here, we examined the effect of intermittent feedback control on postural robustness and of changes in active/passive components on joint coordinative structure. We implemented computer simulation of a quadruple inverted pendulum that is mechanically close to human tiptoe standing. We simulated three pairs of joint viscoelasticity and three choices of neural control strategies for each joint: intermittent, continuous, or passive control. We examined postural robustness for each parameter set by analysing the region of active feedback gain. We found intermittent control at the hip joint was necessary for model stabilisation and model parameters affected the robustness of the pendulum. Joint sways of the pendulum model were partially smaller than or similar to those of experimental data. In conclusion, intermittent feedback control was necessary for the stabilisation of the quadruple inverted pendulum. Also, postural robustness of human-like multi-link standing would be achieved by both passive joint viscoelasticity and neural joint control strategies.

Knockdown of angiopoietin-like 2 mimics the benefits of intermittent fasting on insulin responsiveness and weight loss.

Science.gov (United States)

Martel, Cécile; Pinçon, Anthony; Bélanger, Alexandre Maxime; Luo, Xiaoyan; Gillis, Marc-Antoine; de Montgolfier, Olivia; Thorin-Trescases, Nathalie; Thorin, Éric

2018-01-01

Angiopoietin-like 2 (ANGPTL2) is an inflammatory adipokine linking obesity to insulin resistance. Intermittent fasting, on the other hand, is a lifestyle intervention able to prevent obesity and diabetes but difficult to implement and maintain. Our objectives were to characterize a link between ANGPTL2 and intermittent fasting and to investigate whether the knockdown of ANGPTL2 reproduces the benefits of intermittent fasting on weight gain and insulin responsiveness in knockdown and wild-type littermates mice. Intermittent fasting, access to food ad libitum once every other day, was initiated at the age of three months and maintained for four months. Intermittent fasting decreased by 63% (p < 0.05) gene expression of angptl2 in adipose tissue of wild-type mice. As expected, intermittent fasting improved insulin sensitivity (p < 0.05) and limited weight gain (p < 0.05) in wild-type mice. Knockdown mice fed ad libitum, however, were comparable to wild-type mice following the intermittent fasting regimen: insulin sensitivity and weight gain were identical, while intermittent fasting had no additional impact on these parameters in knockdown mice. Energy intake was similar between both wild-type fed intermittent fasting and ANGPTL2 knockdown mice fed ad libitum, suggesting that intermittent fasting and knockdown of ANGPTL2 equally lower feeding efficiency. These results suggest that the reduction of ANGPTL2 could be a useful and promising strategy to prevent obesity and insulin resistance, although further investigation of the mechanisms linking ANGPTL2 and intermittent fasting is warranted. Impact statement Intermittent fasting is an efficient diet pattern to prevent weight gain and improve insulin sensitivity. It is, however, a difficult regimen to follow and compliance is expected to be very low. In this work, we demonstrate that knockdown of ANGPTL2 in mice fed ad libitum mimics the beneficial effects of intermittent fasting on weight gain and insulin

CT changes in children with drained hydrocephalus and intermittently raised intracranial pressure

International Nuclear Information System (INIS)

Schmidt, H.; Korinthenberg, R.; Erlemann, R.; Lengerke, H.J. von; Muenster Univ.

1987-01-01

Seven children with drained hydrocephalus are described who showed increasingly severe and frequent episodes of intermittently raised intracranial pressure. CT examinations during symptom-free intervals, or after conservative treatment, showed collapsed slit-like ventricles. Examination during attacks of raised pressure showed relative dilatation of the ventricles as compared with earlier examinations. Children with ventricular shunts of long duration may develop a shunt-dependent syndrome; CT may show normal or narrow ventricles and this does not exclude the possibility of a rise of intracranial pressure. These findings may help in making the diagnosis by means of CT without any further invasive procedure. (orig.) [de

Intermittent character of interplanetary magnetic field fluctuations

International Nuclear Information System (INIS)

Bruno, Roberto; Carbone, Vincenzo; Chapman, Sandra; Hnat, Bogdan; Noullez, Alain; Sorriso-Valvo, Luca

2007-01-01

Interplanetary magnetic field magnitude fluctuations are notoriously more intermittent than velocity fluctuations in both fast and slow wind. This behavior 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 the 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

Effects of intermittent hypoxia on running economy.

Science.gov (United States)

Burtscher, M; Gatterer, H; Faulhaber, M; Gerstgrasser, W; Schenk, K

2010-09-01

We investigated the effects of two 5-wk periods of intermittent hypoxia on running economy (RE). 11 male and female middle-distance runners were randomly assigned to the intermittent hypoxia group (IHG) or to the control group (CG). All athletes trained for a 13-wk period starting at pre-season until the competition season. The IHG spent additionally 2 h at rest on 3 days/wk for the first and the last 5 weeks in normobaric hypoxia (15-11% FiO2). RE, haematological parameters and body composition were determined at low altitude (600 m) at baseline, after the 5 (th), the 8 (th) and the 13 (th) week of training. RE, determined by the relative oxygen consumption during submaximal running, (-2.3+/-1.2 vs. -0.3+/-0.7 ml/min/kg, Ptraining phase. Georg Thieme Verlag KG Stuttgart . New York.

Obstructive sleep apnea: role of intermittent hypoxia and inflammation.

Science.gov (United States)

May, Anna M; Mehra, Reena

2014-10-01

Obstructive sleep apnea results in intermittent hypoxia via repetitive upper airway obstruction leading to partial or complete upper airway closure, apneas and hypopneas, respectively. Intermittent hypoxia leads to sympathetic nervous system activation and oxidative stress with a resultant systemic inflammatory cascade. The putative mechanism by which obstructive sleep apnea has been linked to numerous pathologic conditions including stoke, cardiovascular disease, hypertension, and metabolic derangements is through these systemic effects. Treatment of obstructive sleep apnea appears to reduce systemic markers of inflammation and ameliorates the adverse sequelae of this disease. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects—A Narrative Review of Human and Animal Evidence

Directory of Open Access Journals (Sweden)

Michelle Harvie

2017-01-01

Full Text Available Intermittent energy restriction (IER has become popular as a means of weight control amongst people who are overweight and obese, and is also undertaken by normal weight people hoping spells of marked energy restriction will optimise their health. This review summarises randomised comparisons of intermittent and isoenergetic continuous energy restriction for weight loss to manage overweight and obesity. It also summarises the potential beneficial or adverse effects of IER on body composition, adipose stores and metabolic effects from human studies, including studies amongst normal weight subjects and relevant animal experimentation. Six small short term (<6 month studies amongst overweight or obese individuals indicate that intermittent energy restriction is equal to continuous restriction for weight loss, with one study reporting greater reductions in body fat, and two studies reporting greater reductions in HOMA insulin resistance in response to IER, with no obvious evidence of harm. Studies amongst normal weight subjects and different animal models highlight the potential beneficial and adverse effects of intermittent compared to continuous energy restriction on ectopic and visceral fat stores, adipocyte size, insulin resistance, and metabolic flexibility. The longer term benefits or harms of IER amongst people who are overweight or obese, and particularly amongst normal weight subjects, is not known and is a priority for further investigation.

Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects-A Narrative Review of Human and Animal Evidence.

Science.gov (United States)

Harvie, Michelle; Howell, Anthony

2017-01-19

Intermittent energy restriction (IER) has become popular as a means of weight control amongst people who are overweight and obese, and is also undertaken by normal weight people hoping spells of marked energy restriction will optimise their health. This review summarises randomised comparisons of intermittent and isoenergetic continuous energy restriction for weight loss to manage overweight and obesity. It also summarises the potential beneficial or adverse effects of IER on body composition, adipose stores and metabolic effects from human studies, including studies amongst normal weight subjects and relevant animal experimentation. Six small short term (<6 month) studies amongst overweight or obese individuals indicate that intermittent energy restriction is equal to continuous restriction for weight loss, with one study reporting greater reductions in body fat, and two studies reporting greater reductions in HOMA insulin resistance in response to IER, with no obvious evidence of harm. Studies amongst normal weight subjects and different animal models highlight the potential beneficial and adverse effects of intermittent compared to continuous energy restriction on ectopic and visceral fat stores, adipocyte size, insulin resistance, and metabolic flexibility. The longer term benefits or harms of IER amongst people who are overweight or obese, and particularly amongst normal weight subjects, is not known and is a priority for further investigation.

Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects—A Narrative Review of Human and Animal Evidence

Science.gov (United States)

Harvie, Michelle; Howell, Anthony

2017-01-01

Intermittent energy restriction (IER) has become popular as a means of weight control amongst people who are overweight and obese, and is also undertaken by normal weight people hoping spells of marked energy restriction will optimise their health. This review summarises randomised comparisons of intermittent and isoenergetic continuous energy restriction for weight loss to manage overweight and obesity. It also summarises the potential beneficial or adverse effects of IER on body composition, adipose stores and metabolic effects from human studies, including studies amongst normal weight subjects and relevant animal experimentation. Six small short term (obese individuals indicate that intermittent energy restriction is equal to continuous restriction for weight loss, with one study reporting greater reductions in body fat, and two studies reporting greater reductions in HOMA insulin resistance in response to IER, with no obvious evidence of harm. Studies amongst normal weight subjects and different animal models highlight the potential beneficial and adverse effects of intermittent compared to continuous energy restriction on ectopic and visceral fat stores, adipocyte size, insulin resistance, and metabolic flexibility. The longer term benefits or harms of IER amongst people who are overweight or obese, and particularly amongst normal weight subjects, is not known and is a priority for further investigation. PMID:28106818

Composeable Chat over Low-Bandwidth Intermittent Communication Links

National Research Council Canada - National Science Library

Wilcox, D. R

2007-01-01

Intermittent low-bandwidth communication environments, such as those encountered in U.S. Navy tactical radio and satellite links, have special requirements that do not pertain to commercial applications...

Study of intermittent bifurcations and chaos in boost PFC converters by nonlinear discrete models

International Nuclear Information System (INIS)

Zhang Hao; Ma Xikui; Xue Bianling; Liu Weizeng

2005-01-01

This paper mainly deals with nonlinear phenomena like intermittent bifurcations and chaos in boost PFC converters under peak-current control mode. Two nonlinear models in the form of discrete maps are derived to describe precisely the nonlinear dynamics of boost PFC converters from two points of view, i.e., low- and high-frequency regimes. Based on the presented discrete models, both the evolution of intermittent behavior and the periodicity of intermittency are investigated in detail from the fast and slow-scale aspects, respectively. Numerical results show that the occurrence of intermittent bifurcations and chaos with half one line period is one of the most distinguished dynamical characteristics. Finally, we make some instructive conclusions, which prove to be helpful in improving the performances of practical circuits

Modified fenestration with restorative spinoplasty for lumbar spinal stenosis.

Science.gov (United States)

Matsudaira, Ko; Yamazaki, Takashi; Seichi, Atsushi; Hoshi, Kazuto; Hara, Nobuhiro; Ogiwara, Satoshi; Terayama, Sei; Chikuda, Hirotaka; Takeshita, Katsushi; Nakamura, Kozo

2009-06-01

The authors developed an original procedure, modified fenestration with restorative spinoplasty (MFRS) for the treatment of lumbar spinal stenosis. The first step is to cut the spinous process in an L-shape, which is caudally reflected. This procedure allows easy access to the spinal canal, including lateral recesses, and makes it easy to perform a trumpet-style decompression of the nerve roots without violating the facet joints. After the decompression of neural tissues, the spinous process is anatomically restored (spinoplasty). The clinical outcomes at 2 years were evaluated using the Japanese Orthopaedic Association (JOA) scale and patients' satisfaction. Radiological follow-up included radiographs and CT. Between January 2000 and December 2002, 109 patients with neurogenic intermittent claudication with or without mild spondylolisthesis underwent MFRS. Of these, 101 were followed up for at least 2 years (follow-up rate 93%). The average score on the self-administered JOA scale in 89 patients without comorbidity causing gait disturbance improved from 13.3 preoperatively to 22.9 at 2 years' follow-up. Neurogenic intermittent claudication disappeared in all cases. The patients' assessment of treatment satisfaction was "satisfied" in 74 cases, "slightly satisfied" in 12, "slightly dissatisfied" in 2, and "dissatisfied" in 1 case. In 16 cases (18%), a minimum progression of slippage occurred, but no symptomatic instability or recurrent stenosis was observed. Computed tomography showed that the lateral part of the facet joints was well preserved, and the mean residual ratio was 80%. The MFRS technique produces an adequate and safe decompression of the spinal canal, even in patients with narrow and steep facet joints in whom conventional fenestration is technically demanding.

PROPAGATION OF RELATIVISTIC, HYDRODYNAMIC, INTERMITTENT JETS IN A ROTATING, COLLAPSING GRB PROGENITOR STAR

Energy Technology Data Exchange (ETDEWEB)

Geng, Jin-Jun [School of Astronomy and Space Science, Nanjing University, Nanjing 210046 (China); Zhang, Bing [Department of Physics and Astronomy, University of Nevada Las Vegas, NV 89154 (United States); Kuiper, Rolf, E-mail: gengjinjun@gmail.com, E-mail: zhang@physics.unlv.edu [Institute of Astronomy and Astrophysics, University of Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen (Germany)

2016-12-10

The prompt emission of gamma-ray bursts (GRBs) is characterized by rapid variabilities, which may be a direct reflection of the unsteady central engine. We perform a series of axisymmetric 2.5-dimensional simulations to study the propagation of relativistic, hydrodynamic, intermittent jets through the envelope of a GRB progenitor star. A realistic rapidly rotating star is incorporated as the background of jet propagation, and the star is allowed to collapse due to the gravity of the central black hole. By modeling the intermittent jets with constant-luminosity pulses with equal on and off durations, we investigate how the half period, T , affects the jet dynamics. For relatively small T values (e.g., 0.2 s), the jet breakout time t {sub bo} depends on the opening angle of the jet, with narrower jets more penetrating and reaching the surface at shorter times. For T  ≤ 1 s, the reverse shock (RS) crosses each pulse before the jet penetrates through the stellar envelope. As a result, after the breakout of the first group of pulses at t {sub bo}, several subsequent pulses vanish before penetrating the star, causing a quiescent gap. For larger half periods ( T = 2.0 and 4.0 s), all the pulses can successfully penetrate through the envelope, since each pulse can propagate through the star before the RS crosses the shell. Our results may interpret the existence of a weak precursor in some long GRBs, given that the GRB central engine injects intermittent pulses with a half period T  ≤ 1 s. The observational data seem to be consistent with such a possibility.

Synchronization of Hierarchical Time-Varying Neural Networks Based on Asynchronous and Intermittent Sampled-Data Control.

Science.gov (United States)

Xiong, Wenjun; Patel, Ragini; Cao, Jinde; Zheng, Wei Xing

In this brief, our purpose is to apply asynchronous and intermittent sampled-data control methods to achieve the synchronization of hierarchical time-varying neural networks. The asynchronous and intermittent sampled-data controllers are proposed for two reasons: 1) the controllers may not transmit the control information simultaneously and 2) the controllers cannot always exist at any time . The synchronization is then discussed for a kind of hierarchical time-varying neural networks based on the asynchronous and intermittent sampled-data controllers. Finally, the simulation results are given to illustrate the usefulness of the developed criteria.In this brief, our purpose is to apply asynchronous and intermittent sampled-data control methods to achieve the synchronization of hierarchical time-varying neural networks. The asynchronous and intermittent sampled-data controllers are proposed for two reasons: 1) the controllers may not transmit the control information simultaneously and 2) the controllers cannot always exist at any time . The synchronization is then discussed for a kind of hierarchical time-varying neural networks based on the asynchronous and intermittent sampled-data controllers. Finally, the simulation results are given to illustrate the usefulness of the developed criteria.

Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects—A Narrative Review of Human and Animal Evidence

OpenAIRE

Howell, Anthony; Harvie, Michelle

2017-01-01

Intermittent energy restriction (IER) has become popular as a means of weight control amongst people who are overweight and obese, and is also undertaken by normal weight people hoping spells of marked energy restriction will optimise their health. This review summarises randomised comparisons of intermittent and isoenergetic continuous energy restriction for weight loss to manage overweight and obesity. It also summarises the potential beneficial or adverse effects of IER on body composition...

Effect of Linguizhugan decoction on hyperlipidemia rats with intermittent fasting.

Science.gov (United States)

Yang, Yubin; Qin, Jian; Ke, Bin; Zhang, Junjie; Shi, Lanying; Li, Qiong

2013-04-01

To explore the effect of Linguizhugan decoction on hyperlipidemia rats with caloric restriction. The hyperlipidemia model of rat was induced by high fat diet for 8 weeks. After the model was established, 26 rats were randomly divided into 4 groups: the control group (n = 6), the model group (n = 6), the intermittent fasting (IF) group (n = 8), and the IF and herbal medicine (IFH) group (n = 6). IF group was applied intermittent fasting every other day. The IFH group was given Linguizhugan decoction every day and intermittent fasting every other day. Blood samples were taken at the end of 16 weeks, and serum ghrelin and lipid was tested. Serum ghrelin in the IF group significantly increased (P < 0.01). Serum ghrelin in IFH group was lower than the IF group (P < 0.05), but higher than the model group (P < 0.01). Linguizhugan decoction may play a part in regulation of energy and appetite in hyperlipidemia rats with IF.

Water quality effects of intermittent water supply in Arraiján, Panama.

Science.gov (United States)

Erickson, John J; Smith, Charlotte D; Goodridge, Amador; Nelson, Kara L

2017-05-01

Intermittent drinking water supply is common in low- and middle-income countries throughout the world and can cause water quality to degrade in the distribution system. In this study, we characterized water quality in one study zone with continuous supply and three zones with intermittent supply in the drinking water distribution network in Arraiján, Panama. Low or zero pressures occurred in all zones, and negative pressures occurred in the continuous zone and two of the intermittent zones. Despite hydraulic conditions that created risks for backflow and contaminant intrusion, only four of 423 (0.9%) grab samples collected at random times were positive for total coliform bacteria and only one was positive for E. coli. Only nine of 496 (1.8%) samples had turbidity >1.0 NTU and all samples had ≥0.2 mg/L free chlorine residual. In contrast, water quality was often degraded during the first-flush period (when supply first returned after an outage). Still, routine and first-flush water quality under intermittent supply was much better in Arraiján than that reported in a previous study conducted in India. Better water quality in Arraiján could be due to better water quality leaving the treatment plant, shorter supply outages, higher supply pressures, a more consistent and higher chlorine residual, and fewer contaminant sources near pipes. The results illustrate that intermittent supply and its effects on water quality can vary greatly between and within distribution networks. The study also demonstrated that monitoring techniques designed specifically for intermittent supply, such as continuous pressure monitoring and sampling the first flush, can detect water quality threats and degradation that would not likely be detected with conventional monitoring. Copyright © 2017 Elsevier Ltd. All rights reserved.

Intermittent preventive treatment of malaria in pregnancy

DEFF Research Database (Denmark)

Mbonye, A.K.; Hansen, Kristian Schultz; Bygbjerg, Ib Christian

2008-01-01

The main objective of this study was to assess whether traditional birth attendants, drug-shop vendors, community reproductive health workers and adolescent peer mobilisers could administer intermittent preventive treatment (IPTp) with sulfadoxine-pyrimethamine (SP) to pregnant women. The study w...

Investigation of intermittency in simulated and experimental turbulence data by wavelet analysis

International Nuclear Information System (INIS)

Mahdizadeh, N.; Ramisch, M.; Stroth, U.; Lechte, C.; Scott, B.D.

2004-01-01

Turbulent transport in magnetized plasmas has an intermittent nature. Peaked probability density functions and a 1/frequency decay of the power spectra have been interpreted as signs of self-organized criticality generated, similar to a sand pile, by the critical gradients of ion- (ITG) or electron-temperature-gradient (ETG) driven instabilities. In order to investigate the degree of intermittency in toroidally confined plasmas in the absence of critical pressure or temperature gradients, data from the drift-Alfven-wave turbulence code DALF3 [B. Scott, Plasma Phys. Controlled Fusion 39, 1635 (1997)], running with a fixed background pressure gradient, and from a weakly driven low-temperature plasma are analyzed. The intermittency is studied on different temporal scales, which are separated by a wavelet transform. Simulated and experimental data reproduce the results on intermittent transport found in fusion plasmas. It can therefore be expected that in fusion plasmas, too, a substantial fraction of the bursty nature of turbulent transport is not related to avalanches caused by a critical gradient as generated by ITG or ETG turbulence

Mouse Intermittent Hypoxia Mimicking Apnea of Prematurity: Effects on Myelinogenesis and Axonal Maturation

Science.gov (United States)

CAI, JUN; TUONG, CHI MINH; ZHANG, YIPING; SHIELDS, CHRISTOPHER B.; GUO, GANG; FU, HUI; GOZAL, DAVID

2014-01-01

Premature babies are at high risk for both infantile apnea and long-term neurobehavioral deficits. Recent studies suggest that diffuse structural changes in brain white matter are a positive predictor of poor cognitive outcomes. Since oligodendrocyte maturation, myelination, axon development and synapse formation mainly occur in the 3rd trimester of gestation and 1st postnatal year, infantile apnea could lead to and/or exaggerate white matter impairments in preterm neonates. Therefore, we investigated oligodendroglia and axon development in a neonatal mouse model of intermittent hypoxia between postnatal days 2 to 10. During critical phases of central nervous system development, intermittent hypoxia induced hypomyelination in the corpus callosum, striatum, fornix and cerebellum, but not the pons or spinal cord. Intermittent hypoxia-elicited alterations in myelin-forming processes were reflected by decreased expression of myelin proteins, including MBP, PLP, MAG and CNPase, possibly due to arrested maturation of oligodendrocytes. Ultra-structural abnormalities were apparent in the myelin sheath and axon. Immature oligodendrocytes were more vulnerable to neonatal intermittent hypoxia exposures than developing axons, suggesting that hypomyelination may contribute, at least partially, to axonal deficits. Insufficient neurofilament synthesis with anomalous components of neurofilament subunits, β-tubulin and MAP2 isoforms indicated immaturity of axons in intermittent hypoxia-exposed mouse brains. In addition, down-regulation of Synapsin I, Synaptophysin and Gap-43 phosphorylation suggested a potential stunt in axonogenesis and synaptogenesis. The region-selective and complex impairment in brain white matter induced by intermittent hypoxia was further associated with electrophysiological changes that may underlie long-term neurobehavioral sequelae. PMID:21953180

Fractal structures and intermittency in QCD

International Nuclear Information System (INIS)

Gustafson, Goesta.

1990-04-01

New results are presented for fractal structures and intermittency in QCD parton showers. A geometrical interpretation of the anomalous dimension in QCD is given. It is shown that model predications for factorial moments in the PEP-PETRA energy range are increased. if the properties of directly produced pions are more carefully taken into account

Intermittent Moderate Energy Restriction Improves Weight Loss Efficiency in Diet-Induced Obese Mice.

Directory of Open Access Journals (Sweden)

Radhika V Seimon

Full Text Available Intermittent severe energy restriction is popular for weight management. To investigate whether intermittent moderate energy restriction may improve this approach by enhancing weight loss efficiency, we conducted a study in mice, where energy intake can be controlled.Male C57/Bl6 mice that had been rendered obese by an ad libitum diet high in fat and sugar for 22 weeks were then fed one of two energy-restricted normal chow diets for a 12-week weight loss phase. The continuous diet (CD provided 82% of the energy intake of age-matched ad libitum chow-fed controls. The intermittent diet (ID provided cycles of 82% of control intake for 5-6 consecutive days, and ad libitum intake for 1-3 days. Weight loss efficiency during this phase was calculated as (total weight change ÷ [(total energy intake of mice on CD or ID-(total average energy intake of controls]. Subsets of mice then underwent a 3-week weight regain phase involving ad libitum re-feeding.Mice on the ID showed transient hyperphagia relative to controls during each 1-3-day ad libitum feeding period, and overall ate significantly more than CD mice (91.1±1.0 versus 82.2±0.5% of control intake respectively, n = 10, P<0.05. There were no significant differences between CD and ID groups at the end of the weight loss or weight regain phases with respect to body weight, fat mass, circulating glucose or insulin concentrations, or the insulin resistance index. Weight loss efficiency was significantly greater with ID than with CD (0.042±0.007 versus 0.018±0.001 g/kJ, n = 10, P<0.01. Mice on the CD exhibited significantly greater hypothalamic mRNA expression of proopiomelanocortin (POMC relative to ID and control mice, with no differences in neuropeptide Y or agouti-related peptide mRNA expression between energy-restricted groups.Intermittent moderate energy restriction may offer an advantage over continuous moderate energy restriction, because it induces significantly greater weight loss relative

Cardiovascular disease in obstructive sleep apnoea syndrome: the role of intermittent hypoxia and inflammation.

LENUS (Irish Health Repository)

Garvey, J F

2012-02-01

There is increasing evidence that intermittent hypoxia plays a role in the development of cardiovascular risk in obstructive sleep apnoea syndrome (OSAS) through the activation of inflammatory pathways. The development of translational models of intermittent hypoxia has allowed investigation of its role in the activation of inflammatory mechanisms and promotion of cardiovascular disease in OSAS. There are noticeable differences in the response to intermittent hypoxia between body tissues but the hypoxia-sensitive transcription factors hypoxia-inducible factor-1 and nuclear factor-kappaB appear to play a key role in mediating the inflammatory and cardiovascular consequences of OSAS. Expanding our understanding of these pathways, the cross-talk between them and the activation of inflammatory mechanisms by intermittent hypoxia in OSAS will provide new avenues of therapeutic opportunity for the disease.

Metabolic syndrome in patients with prostate cancer undergoing intermittent androgen-deprivation therapy.

Science.gov (United States)

Rezaei, Mohammadali Mohammadzadeh; Rezaei, Mohammadhadi Mohammadzadeh; Ghoreifi, Alireza; Kerigh, Behzad Feyzzadeh

2016-01-01

The presence of metabolic syndrome in men with prostate cancer (PCa) undergoing androgen-deprivation therapy (ADT), especially intermittent type, has not been completely evaluated. The aim of this study is to evaluate metabolic syndrome in men with PCa undergoing intermittent ADT. In this longitudinal study, we studied the prevalence of metabolic syndrome and its components in 190 patients who were undergoing intermittent ADT. The metabolic syndrome was defined according to the Adult Treatment Panel III criteria. All metabolic parameters, including lipid profile, blood glucose, blood pressures, and waist circumferences of the patients were measured six and 12 months after treatment. Mean age of the patients was 67.5 ± 6.74 years. The incidence of metabolic syndrome after six and 12 months was 6.8% and 14.7%, respectively. Analysis of various components of the metabolic syndrome revealed that patients had significantly higher overall prevalence of hyperglycemia, abdominal obesity, and hypertriglyceridemia in their six- and 12-month followups, but blood pressure has not been changed in the same period except for diastolic blood pressure after six months. Although there was an increased risk of metabolic syndrome in patients receiving intermittent ADT, it was lower than other studies that treated the same patients with continuous ADT. Also it seems that intermittent ADT has less metabolic complications than continuous ADT and could be used as a safe alternative in patients with advanced and metastatic PCa.

Coherent and intermittent ensemble oscillations emerge from networks of irregular spiking neurons.

Science.gov (United States)

Hoseini, Mahmood S; Wessel, Ralf

2016-01-01

Local field potential (LFP) recordings from spatially distant cortical circuits reveal episodes of coherent gamma oscillations that are intermittent, and of variable peak frequency and duration. Concurrently, single neuron spiking remains largely irregular and of low rate. The underlying potential mechanisms of this emergent network activity have long been debated. Here we reproduce such intermittent ensemble oscillations in a model network, consisting of excitatory and inhibitory model neurons with the characteristics of regular-spiking (RS) pyramidal neurons, and fast-spiking (FS) and low-threshold spiking (LTS) interneurons. We find that fluctuations in the external inputs trigger reciprocally connected and irregularly spiking RS and FS neurons in episodes of ensemble oscillations, which are terminated by the recruitment of the LTS population with concurrent accumulation of inhibitory conductance in both RS and FS neurons. The model qualitatively reproduces experimentally observed phase drift, oscillation episode duration distributions, variation in the peak frequency, and the concurrent irregular single-neuron spiking at low rate. Furthermore, consistent with previous experimental studies using optogenetic manipulation, periodic activation of FS, but not RS, model neurons causes enhancement of gamma oscillations. In addition, increasing the coupling between two model networks from low to high reveals a transition from independent intermittent oscillations to coherent intermittent oscillations. In conclusion, the model network suggests biologically plausible mechanisms for the generation of episodes of coherent intermittent ensemble oscillations with irregular spiking neurons in cortical circuits. Copyright © 2016 the American Physiological Society.

Intermittency exponent of the turbulent energy cascade

International Nuclear Information System (INIS)

Cleve, J.; Greiner, M.; Pearson, B.R.; Sreenivasan, K.R.

2006-12-01

We consider the turbulent energy dissipation from one-dimensional records in experiments using air and gaseous helium at cryogenic temperatures, and obtain the intermittency exponent via the two-point correlation function of the energy dissipation. The air data are obtained in a number of flows in a wind tunnel and the atmospheric boundary layer at a height of about 35 m above the ground. The helium data correspond to the centerline of a jet exhausting into a container. The air data on the intermittency exponent are consistent with each other and with a trend that increases with the Taylor microscale Reynolds number, R λ , of up to about 1000 and saturates thereafter. On the other hand, the helium data cluster around a constant value at nearly all R λ , this being about half of the asymptotic value for the air data. Some possible explanation is offered for this anomaly. (author)

Determining order-up-to levels under periodic review for compound binomial (intermittent) demand

NARCIS (Netherlands)

Teunter, R. H.; Syntetos, A. A.; Babai, M. Z.

2010-01-01

We propose a new method for determining order-up-to levels for intermittent demand items in a periodic review system. Contrary to existing methods, we exploit the intermittent character of demand by modelling lead time demand as a compound binomial process. in an extensive numerical study using

Intermittent fasting protects against the deterioration of cognitive function, energy metabolism and dyslipidemia in Alzheimer's disease-induced estrogen deficient rats.

Science.gov (United States)

Shin, Bae Kun; Kang, Suna; Kim, Da Sol; Park, Sunmin

2018-02-01

Intermittent fasting may be an effective intervention to protect against age-related metabolic disturbances, although it is still controversial. Here, we investigated the effect of intermittent fasting on the deterioration of the metabolism and cognitive functions in rats with estrogen deficiency and its mechanism was also explored. Ovariectomized rats were infused with β-amyloid (25-35; Alzheimer's disease) or β-amyloid (35-25, Non-Alzheimer's disease; normal cognitive function) into the hippocampus. Each group was randomly divided into two sub-groups: one with intermittent fasting and the other fed ad libitum: Alzheimer's disease-ad libitum, Alzheimer's disease-intermittent fasting, Non-Alzheimer's disease-ad libitum, and Non-Alzheimer's disease-intermittent fasting. Rats in the intermittent fasting groups had a restriction of food consumption to a 3-h period every day. Each group included 10 rats and all rats fed a high-fat diet for four weeks. Interestingly, Alzheimer's disease increased tail skin temperature more than Non-Alzheimer's disease and intermittent fasting prevented the increase. Alzheimer's disease reduced bone mineral density in the spine and femur compared to the Non-Alzheimer's disease, whereas bone mineral density in the hip and leg was reduced by intermittent fasting. Fat mass only in the abdomen was decreased by intermittent fasting. Intermittent fasting decreased food intake without changing energy expenditure. Alzheimer's disease increased glucose oxidation, whereas intermittent fasting elevated fat oxidation as a fuel source. Alzheimer's disease and intermittent fasting deteriorated insulin resistance in the fasting state but intermittent fasting decreased serum glucose levels after oral glucose challenge by increasing insulin secretion. Alzheimer's disease deteriorated short and spatial memory function compared to the Non-Alzheimer's disease, whereas intermittent fasting prevented memory loss in comparison to ad libitum. Unexpectedly

The efficacy of transcutaneous electrical nerve stimulation on the improvement of walking distance in patients with peripheral arterial disease with intermittent claudication: study protocol for a randomised controlled trial: the TENS-PAD study.

Science.gov (United States)

Besnier, Florent; Sénard, Jean-Michel; Grémeaux, Vincent; Riédel, Mélanie; Garrigues, Damien; Guiraud, Thibaut; Labrunée, Marc

2017-08-10

In patients with peripheral arterial disease (PAD), walking improvements are often limited by early pain onset due to vascular claudication. It would thus appear interesting to develop noninvasive therapeutic strategies, such as transcutaneous electrical nerve stimulation (TENS), to improve the participation of PAD patients in rehabilitation programmes, and thus improve their quality of life. Our team recently tested the efficacy of a single 45-min session of 10-Hz TENS prior to walking. TENS significantly delayed pain onset and increased the pain-free walking distance in patients with class-II PAD. We now seek to assess the efficacy of a chronic intervention that includes the daily use of TENS for 3 weeks (5 days a week) on walking distance in Leriche-Fontaine stage-II PAD patients. This is a prospective, double-blind, multicentre, randomised, placebo-controlled trial. One hundred subjects with unilateral PAD (Leriche-Fontaine stage II) will be randomised into two groups (1:1). For the experimental group (TENS group): the treatment will consist of stimulation of the affected leg (at a biphasic frequency of 10 Hz, with a pulse width of 200 μs, maximal intensity below the motor threshold) for 45 min per day, in the morning before the exercise rehabilitation programme, for 3 weeks, 5 days per week. For the control group (SHAM group): the placebo stimulation will be delivered according to the same modalities as for the TENS group but with a voltage level automatically falling to zero after 10 s of stimulation. First outcome: walking distance without pain. transcutaneous oxygen pressure (TcPO 2 ) measured during a Strandness exercise test, peak oxygen uptake (VO 2 peak), endothelial function (EndoPAT®), Ankle-brachial Pressure Index, Body Mass Index, lipid profile (LDL-C, HDL-C, triglycerides), fasting glycaemia, HbA1c level, and the WELCH questionnaire. TENS-PAD is the first randomised controlled trial that uses transcutaneous electrical therapy as an

Intermittent fasting decreases oxidative stress parameters in Wistar rats (Rattus norvegicus)

OpenAIRE

Titis Nurmasitoh; Shindy Yudha Utami; Endah Kusumawardani; Abdulhalim Ahmad Najmuddin; Ika Fidianingsih

2018-01-01

Background Chronic and degenerative diseases are closely related to modern lifestyles that tend to be deficient in physical activity but excessive in food intake. One method used to overcome this problem is dietary restriction through intermittent fasting. Intermittent fasting decreases the risk of chronic and degenerative diseases, e.g. by lowering oxidative stress. Oxidative stress can be determined from the malondialdehyde (MDA) levels and lipid profile in the blood. The present study a...

Clean intermittent self-catheterisation - principles and practice

Directory of Open Access Journals (Sweden)

Arun Narayanaswamy

2000-01-01

Full Text Available This review of the literature on the principles and prac-tice of clean intermittent self-catheterisation includes the role of antiseptics/antibiotics, and outcome. It covers ac-ceptance of the technique, urinary tract infection, conti-nence, and preservation of upper urinary tract.

Intermittent and global transitions in plasma turbulence

International Nuclear Information System (INIS)

Vlad, M.; Spineanu, F.; Itoh, K.; Itoh, S.-I.

2003-07-01

The dynamics of the transition processes in plasma turbulence described by the nonlinear Langevin equation (1) is studied. We show that intermittent or global transitions between metastable states can appear. The conditions for the generation of these transitions and their statistical characteristics are determined. (author)

The two normalization schemes of factorial moments in high energy collisions and the dependence intermittency degree on average transverse momentum

International Nuclear Information System (INIS)

Wu Yuanfnag; Liu Lianshou

1992-01-01

The two different normalization scheme of factorial moments are analyzed carefully. It is found that in both the cases of fixed multiplicity and of intermittency independent of multiplicity, the intermittency indexes obtained from these two normalization schemes are equal to each other. In the case of non-fixed multiplicity and intermittency depending on multiplicity, the formulae expressing the intermittency indexes from the two different normalization schemes in terms of the dynamical index are given. The experimentally observed dependency of intermittency degree on transverse momentum cut is fully recovered by means of the assumption that intermittency degree depends on average transverse momentum per event. It confirms importance of the dependency of intermittency on average momentum

77 FR 67743 - Federal Employees Health Benefits Program Coverage for Certain Intermittent Employees

Science.gov (United States)

2012-11-14

... employees who work on intermittent schedules eligible to be enrolled in a health benefits plan under the... put their health and safety at risk in order to assist those who have been affected by the storm... health insurance coverage based on the potentially diverse work schedules of intermittent employees...

Affecting Factors and Outcome on Intermittent Internet Pulling Behavior in Taiwan's Undergraduate Students

Science.gov (United States)

Yang, Hui-Jen; Lay, Yun-Long

2011-01-01

Nowadays people's lives heavily rely on Internet facilities. Internet users generally have constant Internet connectivity and intermittently click on sites they want to access even amidst studying or working. In this study, we sought to examine the factors affecting intermittent Internet pulling behavior on undergraduate students. Furthermore, the…

Intermittent versus Persistent Wolff-Parkinson-White Syndrome in Children: Electrophysiologic Properties and Clinical Outcomes.

Science.gov (United States)

Kiger, Michelle E; McCanta, Anthony C; Tong, Suhong; Schaffer, Michael; Runciman, Martin; Collins, Kathryn K

2016-01-01

Intermittent Wolff-Parkinson-White (WPW) syndrome is considered to have a lower risk of sudden death. Fewer data exist regarding electrophysiologic (EP) characteristics and the natural history of intermittent WPW in children. All patients with WPW age 1-18 years at a single institution (1996-2013) were reviewed. Patients with intermittent preexcitation were compared to those with loss of preexcitation on Holter/exercise testing and those with persistent preexcitation. High-risk accessory pathway (AP) was defined as AP effective refractory period (APERP), block cycle length, or shortest preexcited RR interval during atrial fibrillation ≤250 ms. A total of 295 patients were included: 226 (76.6%) persistent, 39 (13.2%) intermittent, and 30 (10.2%) loss of preexcitation Holter/exercise. There were no differences in symptoms between groups. Median interquartile range APERP was significantly longer in intermittent WPW (380 [320, 488] ms vs 320 [300, 350] ms persistent, 310 [290, 330] ms loss of preexcitation Holter/exercise; P = 0.0008). At baseline, there was no difference between groups in frequency of high-risk pathways. However, when isoproterenol values were included, high-risk pathways were more frequent among patients with loss of preexcitation on Holter/exercise (54% vs 16% persistent, 11% intermittent; P = 0.005). There was one death in a patient with loss of preexcitation on exercise testing, no EP study, and prior drug use. A second patient with persistent WPW and APERP 270 ms required resuscitation following a methadone overdose. Intermittent preexcitation in children does not connote a lower risk AP by EP criteria or reduced symptoms. The low number of pediatric WPW patients who develop preexcited atrial fibrillation or sudden death warrants larger studies to investigate these outcomes. ©2015 Wiley Periodicals, Inc.

Characterization and consequences of intermittent sediment oxygenation by macrofauna: interpretation of high-resolution data sets

Science.gov (United States)

Meile, C. D.; Dwyer, I.; Zhu, Q.; Polerecky, L.; Volkenborn, N.

2017-12-01

Mineralization of organic matter in marine sediments leads to the depletion of oxygen, while activities of infauna introduce oxygenated seawater to the subsurface. In permeable sediments solutes can be transported from animals and their burrows into the surrounding sediment through advection over several centimeters. The intermittency of pumping leads to a spatially heterogeneous distribution of oxidants, with the temporal dynamics depending on sediment reactivity and activity patterns of the macrofauna. Here, we present results from a series of experiments in which these dynamics are studied at high spatial and temporal resolution using planar optodes. From O2, pH and pCO2 optode data, we quantify rates of O2 consumption and dissolved inorganic carbon production, as well alkalinity dynamics, with millimeter-scale resolution. Simulating intermittent irrigation by imposed pumping patterns in thin aquaria, we derive porewater flow patterns, which together with the production and consumption rates cause the chemical distributions and the establishment of reaction fronts. Our analysis thus establishes a quantitative connection between the locally dynamic redox conditions relevant for biogeochemical transformations and macroscopic observations commonly made with sediment cores.

Chronic intermittent hypoxia induces cardiac inflammation and dysfunction in a rat obstructive sleep apnea model.

Science.gov (United States)

Wei, Qin; Bian, Yeping; Yu, Fuchao; Zhang, Qiang; Zhang, Guanghao; Li, Yang; Song, Songsong; Ren, Xiaomei; Tong, Jiayi

2016-11-01

Chronic intermittent hypoxia is considered to play an important role in cardiovascular pathogenesis during the development of obstructive sleep apnea (OSA). We used a well-described OSA rat model induced with simultaneous intermittent hypoxia. Male Sprague Dawley rats were individually placed into plexiglass chambers with air pressure and components were electronically controlled. The rats were exposed to intermittent hypoxia 8 hours daily for 5 weeks. The changes of cardiac structure and function were examined by ultrasound. The cardiac pathology, apoptosis, and fibrosis were analyzed by H&E staining, TUNNEL assay, and picosirius staining, respectively. The expression of inflammation and fibrosis marker genes was analyzed by quantitative real-time PCR and Western blot. Chronic intermittent hypoxia/low pressure resulted in significant increase of left ventricular internal diameters (LVIDs), end-systolic volume (ESV), end-diastolic volume (EDV), and blood lactate level and marked reduction in ejection fraction and fractional shortening. Chronic intermittent hypoxia increased TUNNEL-positive myocytes, disrupted normal arrangement of cardiac fibers, and increased Sirius stained collagen fibers. The expression levels of hypoxia induced factor (HIF)-1α, NF-kB, IL-6, and matrix metallopeptidase 2 (MMP-2) were significantly increased in the heart of rats exposed to chronic intermittent hypoxia. In conclusion, the left ventricular function was adversely affected by chronic intermittent hypoxia, which is associated with increased expression of HIF-1α and NF-kB signaling molecules and development of cardiac inflammation, apoptosis and fibrosis. © 2016 by the Journal of Biomedical Research. All rights reserved.

Dynamic MR in patients affected by neurogenical claudication: technique and results from a single-center experience

Energy Technology Data Exchange (ETDEWEB)

Muto, Mario; Guarnieri, Gianluigi; Zeccolini, Fabio; Diano, Alvaro [Cardarelli Hospital, Neuroradiology Department, Naples (Italy); Giurazza, Francesco [Universita Campus Bio-Medico di Roma, Radiology Department, Rome (Italy); Senese, Rossana [Emicenter European Medical Imaging, Naples (Italy); Schena, Emiliano [Universita Campus Bio-Medico di Roma, Measurement and Biomedical Instrumentation Laboratory, Rome (Italy)

2016-08-15

This study aimed to determine changes in size of lumbar spinal canal and related articular structures, during dynamic MR scans acquired in symptomatic patients standing upright using a new open MR system. Forty patients (mean age 58.4 years) affected by lumbar back pain associated with claudication, referring symptoms since more than 6 months. No one underwent to previous spine surgery. MR scans were performed with a novel open 0.5-T scanner, patient supine and upright (90 ). Lumbar lordotic angle, flavum ligament thickness, herniated discs, spinal canal area, spinal canal and dural sac antero-posterior diameters, and spinal alignment were measured and compared in both supine and upright positions. Mean scanning time was 43 min. All the considered parameters showed a statistically significant difference, except for lumbar lordotic angle. Mean percentage differences moving from supine to upright were +3.9 % for lumbar lordotic angle, +15 % for flavum ligament thickness, +16.2 % for sagittal disc bulge, -10.8 % for dural sac diameter, -13.1 % for spinal canal diameter, and -15.8 % for spinal canal area. In supine position, no patient presented with spondylolisthesis; moving to upright position, four patients showed spondylolisthesis (grade I). Dynamic MR is a valuable diagnostic exam to analyze the structures involved in lumbar back pain due to spinal canal stenosis and spondylolisthesis; in supine position, relevant factors can be underestimated or hidden, becoming appreciable only patient standing upright. In this series, flavum ligament thickening presented a role comparable to disc bulge for narrowing of lumbar spinal canal. (orig.)

Increased expression of protein kinase A inhibitor alpha (PKI-alpha) and decreased PKA-regulated genes in chronic intermittent alcohol exposure.

Science.gov (United States)

Repunte-Canonigo, Vez; Lutjens, Robert; van der Stap, Lena D; Sanna, Pietro Paolo

2007-03-23

Intermittent models of alcohol exposure that mimic human patterns of alcohol consumption produce profound physiological and biochemical changes and induce rapid increases in alcohol self-administration. We used high-density oligonucleotide microarrays to investigate gene expression changes during chronic intermittent alcohol exposure in three brain regions that receive mesocorticolimbic dopaminergic projections and that are believed to be involved in alcohol's reinforcing actions: the medial prefrontal cortex, the nucleus accumbens and the amygdala. An independent replication of the experiment was used for RT-PCR validation of the microarray results. The protein kinase A inhibitor alpha (PKI-alpha, Pkia), a member of the endogenous PKI family implicated in reducing nuclear PKA activity, was found to be increased in all three regions tested. Conversely, we observed a downregulation of the expression of several PKA-regulated transcripts in one or more of the brain regions studied, including the activity and neurotransmitter-regulated early gene (Ania) - 1, -3, -7, -8, the transcription factors Egr1 and NGFI-B (Nr4a1) and the neuropeptide NPY. Reduced expression of PKA-regulated genes in mesocorticolimbic projection areas may have motivational significance in the rapid increase in alcohol self-administration induced by intermittent alcohol exposure.

Statistical parameter characteristics of gas-phase fluctuations for gas-liquid intermittent flow

Energy Technology Data Exchange (ETDEWEB)

Matsui, G.; Monji, H.; Takaguchi, M. [Univ. of Tsukuba (Japan)

1995-09-01

This study deals with theoretical analysis on the general behaviour of statistical parameters of gas-phase fluctuations and comparison of statistical parameter characteristics for the real void fraction fluctuations measured with those for the wave form modified the real fluctuations. In order to investigate the details of the relation between the behavior of the statistical parameters in real intermittent flow and analytical results obtained from information on the real flow, the distributions of statistical parameters for general fundamental wave form of gas-phase fluctuations are discussed in detail. By modifying the real gas-phase fluctuations to a trapezoidaly wave, the experimental results can be directly compared with the analytical results. The analytical results for intermittent flow show that the wave form parameter, and the total amplitude of void fraction fluctuations, affects strongly on the statistical parameter characteristics. The comparison with experiment using nitrogen gas-water intermittent flow suggests that the parameters of skewness and excess may be better as indicators of flow pattern. That is, the macroscopic nature of intermittent flow can be grasped by the skewness and the excess, and the detailed flow structure may be described by the mean and the standard deviation.

Statistical parameter characteristics of gas-phase fluctuations for gas-liquid intermittent flow

International Nuclear Information System (INIS)

Matsui, G.; Monji, H.; Takaguchi, M.

1995-01-01

This study deals with theoretical analysis on the general behaviour of statistical parameters of gas-phase fluctuations and comparison of statistical parameter characteristics for the real void fraction fluctuations measured with those for the wave form modified the real fluctuations. In order to investigate the details of the relation between the behavior of the statistical parameters in real intermittent flow and analytical results obtained from information on the real flow, the distributions of statistical parameters for general fundamental wave form of gas-phase fluctuations are discussed in detail. By modifying the real gas-phase fluctuations to a trapezoidaly wave, the experimental results can be directly compared with the analytical results. The analytical results for intermittent flow show that the wave form parameter, and the total amplitude of void fraction fluctuations, affects strongly on the statistical parameter characteristics. The comparison with experiment using nitrogen gas-water intermittent flow suggests that the parameters of skewness and excess may be better as indicators of flow pattern. That is, the macroscopic nature of intermittent flow can be grasped by the skewness and the excess, and the detailed flow structure may be described by the mean and the standard deviation

Acute intermittent porphyria presenting as progressive muscular ...

African Journals Online (AJOL)

Acute intermittent porphyria, the most common porphyria affecting the nervous system, typically presents with neurovisceral crises followed by a motor neuropathy. We describe a 23-year-old black South African man presenting with a progressive stuttering, lower motor neuron syndrome developing over months. He had not ...

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

Mobilization of microspheres from a fractured soil during intermittent infiltration events

Science.gov (United States)

Mohanty, Sanjay; Bulicek, Mark; Metge, David W.; Harvey, Ronald W.; Ryan, Joseph N.; Boehm, Alexandria B.

2015-01-01

Pathogens or biocolloids mobilized in the vadose zone may consequently contaminate groundwater. We found that microspheres were mobilized from a fractured soil during intermittent rainfall and the mobilization was greater when the microsphere size was larger and when the soil had greater water permeability.The vadose zone filters pathogenic microbes from infiltrating water and consequently protects the groundwater from possible contamination. In some cases, however, the deposited microbes may be mobilized during rainfall and migrate into the groundwater. We examined the mobilization of microspheres, surrogates for microbes, in an intact core of a fractured soil by intermittent simulated rainfall. Fluorescent polystyrene microspheres of two sizes (0.5 and 1.8 mm) and Br− were first applied to the core to deposit the microspheres, and then the core was subjected to three intermittent infiltration events to mobilize the deposited microspheres. Collecting effluent samples through a 19-port sampler at the base of the core, we found that water flowed through only five ports, and the flow rates varied among the ports by a factor of 12. These results suggest that flow paths leading to the ports had different permeabilities, partly due to macropores. Although 40 to 69% of injected microspheres were retained in the core during their application, 12 to 30% of the retained microspheres were mobilized during three intermittent infiltration events. The extent of microsphere mobilization was greater in flow paths with greater permeability, which indicates that macropores could enhance colloid mobilization during intermittent infiltration events. In all ports, the 1.8-mm microspheres were mobilized to a greater extent than the 0.5-mm microspheres, suggesting that larger colloids are more likely to mobilize. These results are useful in assessing the potential of pathogen mobilization and colloid-facilitated transport of contaminants in the subsurface under natural infiltration

Laboratory investigation on effects of flood intermittency on river delta dynamics

Science.gov (United States)

Miller, K. L.; Kim, W.

2015-12-01

In order to simplify the complex hydrological variability of flow conditions, experiments modeling delta evolution are often conducted using a representative "channel-forming" flood flow and then relate results to field settings using an intermittency factor, defined as the fraction of total time at flood conditions. Although this intermittency factor makes it easier to investigate how variables, such as relative base level and/or sediment supply, affect delta dynamics, little is known about how this generalization to a single flow condition affects delta processes. We conducted a set of laboratory experiments with periodic flow conditions to determine the effects of intermittent discharges on delta evolution. During the experiment, flood with a set water discharge and sediment supply, cycles between periods of normal flow where the water flux is halved and the sediment discharge is turned off. For each run, the magnitude of the flood is held constant, but the duration is assigned differently, thus varying the intermittency between 1 and 0.2. We find that as the intermittency factor decreases (duration of each flood period decreases), the delta topset has a larger, more elongated area with a shallower slope as a result of reworking on the delta topset during normal flow conditions. During periods of normal flow, the system adjusts towards a new equilibrium state that then in turn acts as the initial condition for the subsequent flood period. Furthermore, the natural delta avulsion cycle becomes obscured by the flood cycles as the flood duration becomes shorter than the autogenic behavior. These results suggest that the adjustment timescale for differing flow conditions is a factor in determining the overall shape of the delta and behavior of the fluviodeltaic channels. We conclude, periods of normal flow when topset sediment is reworked, may be just as important to delta dynamics as periods of flood when sediment is supplied to the system.

Effects of intermittent fasting on body composition and clinical health markers in humans.

Science.gov (United States)

Tinsley, Grant M; La Bounty, Paul M

2015-10-01

Intermittent fasting is a broad term that encompasses a variety of programs that manipulate the timing of eating occasions by utilizing short-term fasts in order to improve body composition and overall health. This review examines studies conducted on intermittent fasting programs to determine if they are effective at improving body composition and clinical health markers associated with disease. Intermittent fasting protocols can be grouped into alternate-day fasting, whole-day fasting, and time-restricted feeding. Alternate-day fasting trials of 3 to 12 weeks in duration appear to be effective at reducing body weight (≈3%-7%), body fat (≈3-5.5 kg), total cholesterol (≈10%-21%), and triglycerides (≈14%-42%) in normal-weight, overweight, and obese humans. Whole-day fasting trials lasting 12 to 24 weeks also reduce body weight (≈3%-9%) and body fat, and favorably improve blood lipids (≈5%-20% reduction in total cholesterol and ≈17%-50% reduction in triglycerides). Research on time-restricted feeding is limited, and clear conclusions cannot be made at present. Future studies should examine long-term effects of intermittent fasting and the potential synergistic effects of combining intermittent fasting with exercise. © The Author(s) 2015. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Atomistic Model of Fluorescence Intermittency of Colloidal Quantum Dots

KAUST Repository

Voznyy, O.; Sargent, E. H.

2014-01-01

with foreign cations can stabilize the vacancies, inhibiting intermittency and improving quantum yield, providing an explanation of recent experimental observations. © 2014 American Physical Society.

Tangent map intermittency as an approximate analysis of intermittency in a high dimensional fully stochastic dynamical system: The Tangled Nature model.

Science.gov (United States)

Diaz-Ruelas, Alvaro; Jeldtoft Jensen, Henrik; Piovani, Duccio; Robledo, Alberto

2016-12-01

It is well known that low-dimensional nonlinear deterministic maps close to a tangent bifurcation exhibit intermittency and this circumstance has been exploited, e.g., by Procaccia and Schuster [Phys. Rev. A 28, 1210 (1983)], to develop a general theory of 1/f spectra. This suggests it is interesting to study the extent to which the behavior of a high-dimensional stochastic system can be described by such tangent maps. The Tangled Nature (TaNa) Model of evolutionary ecology is an ideal candidate for such a study, a significant model as it is capable of reproducing a broad range of the phenomenology of macroevolution and ecosystems. The TaNa model exhibits strong intermittency reminiscent of punctuated equilibrium and, like the fossil record of mass extinction, the intermittency in the model is found to be non-stationary, a feature typical of many complex systems. We derive a mean-field version for the evolution of the likelihood function controlling the reproduction of species and find a local map close to tangency. This mean-field map, by our own local approximation, is able to describe qualitatively only one episode of the intermittent dynamics of the full TaNa model. To complement this result, we construct a complete nonlinear dynamical system model consisting of successive tangent bifurcations that generates time evolution patterns resembling those of the full TaNa model in macroscopic scales. The switch from one tangent bifurcation to the next in the sequences produced in this model is stochastic in nature, based on criteria obtained from the local mean-field approximation, and capable of imitating the changing set of types of species and total population in the TaNa model. The model combines full deterministic dynamics with instantaneous parameter random jumps at stochastically drawn times. In spite of the limitations of our approach, which entails a drastic collapse of degrees of freedom, the description of a high-dimensional model system in terms of a low

Intermittency Statistics in the Expanding Solar Wind

Science.gov (United States)

Cuesta, M. E.; Parashar, T. N.; Matthaeus, W. H.

2017-12-01

The solar wind is observed to be turbulent. One of the open questions in solar wind research is how the turbulence evolves as the solar wind expands to great distances. Some studies have focused on evolution of the outer scale but not much has been done to understand how intermittency evolves in the expanding wind beyond 1 AU (see [1,2]). We use magnetic field data from Voyager I spacecraft from 1 to 10AU to study the evolution of statistics of magnetic discontinuities. We perform various statistical tests on these discontinuities and make connections to the physical processes occurring in the expanding wind.[1] Tsurutani, Bruce T., and Edward J. Smith. "Interplanetary discontinuities: Temporal variations and the radial gradient from 1 to 8.5 AU." Journal of Geophysical Research: Space Physics 84.A6 (1979): 2773-2787.[2] Greco, A., et al. "Evidence for nonlinear development of magnetohydrodynamic scale intermittency in the inner heliosphere." The Astrophysical Journal 749.2 (2012): 105.

Intermittent preventive treatment of malaria in pregnancy

DEFF Research Database (Denmark)

Mbonye, A.K.; Bygbjerg, Ib Christian; Magnussen, Pascal

2008-01-01

OBJECTIVE: To assess whether traditional birth attendants, drug-shop vendors, community reproductive-health workers, or adolescent peer mobilizers could administer intermittent preventive treatment (IPTp) for malaria with sulfadoxine-pyrimethamine to pregnant women. METHODS: A non-randomized comm......OBJECTIVE: To assess whether traditional birth attendants, drug-shop vendors, community reproductive-health workers, or adolescent peer mobilizers could administer intermittent preventive treatment (IPTp) for malaria with sulfadoxine-pyrimethamine to pregnant women. METHODS: A non......-randomized community trial was implemented in 21 community clusters (intervention) and four clusters where health units provided routine IPTp (control). The primary outcome measures were access and adherence to IPTp, number of malaria episodes, prevalence of anaemia, and birth weight. Numbers of live births, abortions......, still births, and maternal and child deaths were secondary endpoints. FINDINGS: 1404 (67.5%) of 2081 with the new delivery system received two doses of sulfadoxine-pyrimethamine versus 281 (39.9%) of 704 with health units (P malaria episodes decreased from 906 (49...

Determine Efficacy of a Short Course of Montelukast in Children with Intermittent Asthma and Viral Infection

Directory of Open Access Journals (Sweden)

Hamid Ahanchian

2013-12-01

Full Text Available Introduction Mild intermittent asthma is common in children and viral infections are responsible for the majority of exacerbations. As leukotrienes are potent inflammatory mediators, some studies have shown that Montelukast, a leukotriene receptor antagonist, may be effective on reduction of asthma symptom. To determine whether a short course of Montelukast in asthmatic children with common cold would modify the severity of an asthma episode.     Materials and Methods Children, aged 6-12 years with intermittent asthma participated in this randomized, double-blind, placebo-controlled clinical trial. Treatment with Montelukast or placebo was initiated at the onset of viral upper respiratory tract infection and continued for 7 days. Primary outcomes included the clinical manifestation: duration of episodes, daily symptom, nights symptoms and activity limitation. Secondary outcomes included the need for beta agonist usage, oral prednisolone, physician visit, hospital admission and school absence.   Results                                                              A total of 187 children with intermittent asthma were randomized, 93 to Montelukast group and 94 to placebo group. Montelukast significantly decreased the cough by 17.3% (P

Intermittent torsion of a normal ovary in a child associated with use of a trampoline.

Science.gov (United States)

Yancey, Lynne M

2012-04-01

Ovarian torsion is rare in children. It usually occurs in the presence of ovarian or pelvic pathology. The course of symptoms is typically hours to days. Some authors have speculated that sudden acceleration/deceleration movements may precipitate torsion. The objective of this report is to describe a case of intermittent abdominal pain lasting nearly 6 months, which started when the child began playing regularly on a trampoline, and was ultimately diagnosed as intermittent ovarian torsion of an otherwise normal ovary. A 12-year-old girl presented to the Emergency Department (ED) with 2 h of abdominal pain and vomiting. She reported similar episodes over the previous 6 months. Initial ultrasound, obtained between episodes, was normal. Repeat ultrasound at ED presentation showed no blood flow to the left adnexa. Surgery confirmed the ovary to be twisted 1080 degrees and markedly edematous due to vascular engorgement. The family retrospectively identified the onset of the first episode as happening the same week the child had begun playing regularly on a trampoline. After surgery, she no longer played on the trampoline. At follow-up 22 months later, she had had no recurrence of her symptoms. Intermittent ovarian torsion should be considered as a rare cause of recurrent abdominal pain in children. The presence of blood flow with Doppler ultrasound during acute symptoms does not exclude the diagnosis. Clinicians might also ask about unusual physical activities because several authors have theorized that ovarian torsion could be precipitated by sudden acceleration/deceleration movements. Copyright © 2012. Published by Elsevier Inc.

Turbulent intermittent structure in non-homogeneous non-local flows

Science.gov (United States)

Mahjoub, O. B.; Castilla, R.; Vindel, J. M.; Redondo, J. M.

2010-05-01

Data from SABLES98 experimental campaign have been used in order to study the influence of stability (from weak to strong stratification) on intermittency [1]. Standard instrumentation, 14 thermocouples and 3 sonic anemometers at three levels (5.8, 13.5 and 32 m) were available in September 1998 and calculations are done in order to evaluate structure functions and the scale to scale characteristics. Using BDF [2-4] as well as other models of cascades, the spectral equilibrium values were used to calculate fluxes of momentum and heat as well as non-homogeneous models and the turbulent mixing produced. The differences in structure and higher order moments between stable, convective and neutral turbulence were used to identify differences in turbulent intermittent mixing and velocity PDF's. The intermittency of atmospheric turbulence in strongly stable situations affected by buoyancy and internal waves are seen to modify the structure functions exponents and intermittency, depending on the modulus of the Richardson's number,Ri, as well as of the Monin-Obukhov and Ozmidov lengthscales. The topological aspects of the turbulence affected by stratification reduce the vertical length-scales to a maximum described by the Thorpe and the Ozmidov lenth-scales, but intermittency, Kurtosis and other higher order descriptors of the turbulence based on spectral wavelet analysis are also affected in a complex way [5,6]. The relationship between stratification, intermittency, µ(Ri) and the fractal dimension of the stable flows and between the dispersion, the fractal dimension are discussed. The data analyzed is from the campaign SABLES-98 at the north-west Iberian Peninsula plateau.(Cuxart et al. 2000). Conditional statistics of the relationship between µ(Ri) are confirmed as in (Vindel et al 2008)[4] and compared with laboratory experiments and with 2D-3D aspects of the turbulence cascade. The use of BDF [3] model comparing the corresponding relative scaling exponents which are

Intermittent hypoxia increases melanoma metastasis to the lung in a mouse model of sleep apnea.

Science.gov (United States)

Almendros, Isaac; Montserrat, Josep M; Torres, Marta; Dalmases, Mireia; Cabañas, Maria L; Campos-Rodríguez, Francisco; Navajas, Daniel; Farré, Ramon

2013-05-01

Obstructive sleep apnea (OSA) has recently been associated with an increased risk of cancer incidence and mortality in humans. Experimental data in mice have also shown that intermittent hypoxia similar to that observed in OSA patients enhances tumor growth. The aim of this study was to test the hypothesis that intermittent hypoxia mimicking OSA enhances lung metastasis. A total of 75 C57BL/6J male mice (10-week-old) were subjected to either spontaneous or induced melanoma lung metastasis. Normoxic animals breathed room air and intermittent hypoxic animals were subjected to cycles of 20s of 5% O2 followed by 40s of room air for 6h/day. Spontaneous and induced lung metastases were studied after subcutaneous and intravenous injection of B16F10 melanoma cells, respectively. Compared with normoxia, intermittent hypoxia induced a significant increase in melanoma lung metastasis. These animal model results suggest that intermittent hypoxia could contribute to cancer metastasis in patients with OSA. Copyright © 2013 Elsevier B.V. All rights reserved.

Intermittent Access to Ethanol Drinking Facilitates the Transition to Excessive Drinking After Chronic Intermittent Ethanol Vapor Exposure.

Science.gov (United States)

Kimbrough, Adam; Kim, Sarah; Cole, Maury; Brennan, Molly; George, Olivier

2017-08-01

Alcohol binge drinking in humans is thought to increase the risk for alcohol use disorder (AUD). Unclear is whether drinking patterns (e.g., bingelike or stable drinking) differentially affect the transition to compulsive-like drinking in dependent individuals. We examined whether chronic bingelike drinking facilitates the transition to compulsive-like drinking in rats. Male Wistar rats were given 5 months of intermittent access to ethanol (EtOH) (IAE) or continuous access to EtOH (CAE) in a 2-bottle choice paradigm. Then, rats were given chronic intermittent EtOH (CIE) vapor exposure. Escalation of EtOH intake and compulsive-like responding for EtOH, using a progressive-ratio schedule of reinforcement and quinine-adulterated EtOH, were measured. IAE rats escalated EtOH drinking after 2 weeks of 2-bottle choice, whereas CAE rats exhibited stable EtOH drinking for 5 months. After 8 weeks of CIE, both IAE + CIE and CAE + CIE rats escalated their EtOH intake. However, IAE rats escalated their EtOH intake weeks sooner than CAE rats and exhibited greater EtOH intake. No differences in compulsive-like responding were found between IAE + CIE and CAE + CIE rats. However, both IAE + CIE and CAE + CIE rats showed strong compulsive-like responding compared with rats without prior IAE or CAE. Chronic EtOH drinking at stable or escalated levels for several months is associated with more compulsive-like responding for EtOH in rats that are exposed to CIE compared with rats without a prior history of EtOH drinking. Moreover, IAE facilitated the transition to compulsive-like responding for EtOH after CIE exposure, reflected by the escalation of EtOH intake. These results suggest that IAE may facilitate the transition to AUD. This study indicates that despite a moderate level of EtOH drinking, the IAE animal model is highly relevant to early stages of alcohol abuse and suggests that it may be associated with neuroadaptations that produce a faster transition to

Intermittency in nuclear multifragmentation

International Nuclear Information System (INIS)

Ploszajczak, M.; Tucholski, A.

1990-07-01

Fluctuations of the fragment size distribution in a percolation model and in nuclear multifragmentation following the breakup of high energy nuclei in the nuclear emulsion are studied using the method of scaled factorial moments. An intermittent patern of fluctuations is found in the data as well as in the percolation lattice calculation. This is a consequence of both a self-similarity in the fragment size distribution and a random character for the scaling law. These fluctuations are in general well-described by percolation model. The multifractal dimensions are calculated and their relevance to the study of possible critical behaviour is pointed out. (orig.)

THE EFFECT OF INTERMITTENT GYRO-SCALE SLAB TURBULENCE ON PARALLEL AND PERPENDICULAR COSMIC-RAY TRANSPORT

International Nuclear Information System (INIS)

Le Roux, J. A.

2011-01-01

Earlier work based on nonlinear guiding center (NLGC) theory suggested that perpendicular cosmic-ray transport is diffusive when cosmic rays encounter random three-dimensional magnetohydrodynamic turbulence dominated by uniform two-dimensional (2D) turbulence with a minor uniform slab turbulence component. In this approach large-scale perpendicular cosmic-ray transport is due to cosmic rays microscopically diffusing along the meandering magnetic field dominated by 2D turbulence because of gyroresonant interactions with slab turbulence. However, turbulence in the solar wind is intermittent and it has been suggested that intermittent turbulence might be responsible for the observation of 'dropout' events in solar energetic particle fluxes on small scales. In a previous paper le Roux et al. suggested, using NLGC theory as a basis, that if gyro-scale slab turbulence is intermittent, large-scale perpendicular cosmic-ray transport in weak uniform 2D turbulence will be superdiffusive or subdiffusive depending on the statistical characteristics of the intermittent slab turbulence. In this paper we expand and refine our previous work further by investigating how both parallel and perpendicular transport are affected by intermittent slab turbulence for weak as well as strong uniform 2D turbulence. The main new finding is that both parallel and perpendicular transport are the net effect of an interplay between diffusive and nondiffusive (superdiffusive or subdiffusive) transport effects as a consequence of this intermittency.

Intermittent fasting preserves beta-cell mass in obesity-induced diabetes via the autophagy-lysosome pathway.

Science.gov (United States)

Liu, Haiyan; Javaheri, Ali; Godar, Rebecca J; Murphy, John; Ma, Xiucui; Rohatgi, Nidhi; Mahadevan, Jana; Hyrc, Krzysztof; Saftig, Paul; Marshall, Connie; McDaniel, Michael L; Remedi, Maria S; Razani, Babak; Urano, Fumihiko; Diwan, Abhinav

2017-01-01

Obesity-induced diabetes is characterized by hyperglycemia, insulin resistance, and progressive beta cell failure. In islets of mice with obesity-induced diabetes, we observe increased beta cell death and impaired autophagic flux. We hypothesized that intermittent fasting, a clinically sustainable therapeutic strategy, stimulates autophagic flux to ameliorate obesity-induced diabetes. Our data show that despite continued high-fat intake, intermittent fasting restores autophagic flux in islets and improves glucose tolerance by enhancing glucose-stimulated insulin secretion, beta cell survival, and nuclear expression of NEUROG3, a marker of pancreatic regeneration. In contrast, intermittent fasting does not rescue beta-cell death or induce NEUROG3 expression in obese mice with lysosomal dysfunction secondary to deficiency of the lysosomal membrane protein, LAMP2 or haplo-insufficiency of BECN1/Beclin 1, a protein critical for autophagosome formation. Moreover, intermittent fasting is sufficient to provoke beta cell death in nonobese lamp2 null mice, attesting to a critical role for lysosome function in beta cell homeostasis under fasting conditions. Beta cells in intermittently-fasted LAMP2- or BECN1-deficient mice exhibit markers of autophagic failure with accumulation of damaged mitochondria and upregulation of oxidative stress. Thus, intermittent fasting preserves organelle quality via the autophagy-lysosome pathway to enhance beta cell survival and stimulates markers of regeneration in obesity-induced diabetes.

THE EFFECT OF INTERMITTENT GYRO-SCALE SLAB TURBULENCE ON PARALLEL AND PERPENDICULAR COSMIC-RAY TRANSPORT

Energy Technology Data Exchange (ETDEWEB)

Le Roux, J. A. [Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

2011-12-10

Earlier work based on nonlinear guiding center (NLGC) theory suggested that perpendicular cosmic-ray transport is diffusive when cosmic rays encounter random three-dimensional magnetohydrodynamic turbulence dominated by uniform two-dimensional (2D) turbulence with a minor uniform slab turbulence component. In this approach large-scale perpendicular cosmic-ray transport is due to cosmic rays microscopically diffusing along the meandering magnetic field dominated by 2D turbulence because of gyroresonant interactions with slab turbulence. However, turbulence in the solar wind is intermittent and it has been suggested that intermittent turbulence might be responsible for the observation of 'dropout' events in solar energetic particle fluxes on small scales. In a previous paper le Roux et al. suggested, using NLGC theory as a basis, that if gyro-scale slab turbulence is intermittent, large-scale perpendicular cosmic-ray transport in weak uniform 2D turbulence will be superdiffusive or subdiffusive depending on the statistical characteristics of the intermittent slab turbulence. In this paper we expand and refine our previous work further by investigating how both parallel and perpendicular transport are affected by intermittent slab turbulence for weak as well as strong uniform 2D turbulence. The main new finding is that both parallel and perpendicular transport are the net effect of an interplay between diffusive and nondiffusive (superdiffusive or subdiffusive) transport effects as a consequence of this intermittency.

Volcano-like intermittent bleeding activity for seven years from an arterio-enteric fistula on a kidney graft site after pancreas-kidney transplantation: a case report

Directory of Open Access Journals (Sweden)

Schölmerich Jürgen

2010-11-01

Full Text Available Abstract Introduction We report the first case of a patient who underwent simultaneous kidney and pancreas transplantation and who then suffered from repeated episodes of severe gastrointestinal bleeding over a period of seven years. Locating the site of gastrointestinal bleeding is a challenging task. This case illustrates that detection of an arterio-enteric fistula can be very difficult, especially in technically-challenging situations such as cases of severe intra-abdominal adhesions. It is important to consider the possibility of arterio-enteric fistulas in cases of intermittent bleeding episodes, especially in transplant patients. Case presentation A 40-year-old Caucasian man received a combined pancreas-kidney transplantation as a result of complications from diabetes mellitus type I. Thereafter, he suffered from intermittent clinically-relevant episodes of gastrointestinal bleeding. Repeat endoscopic, surgical, scintigraphic, and angiographic investigations during his episodes of acute bleeding could not locate the bleeding site. He finally died in hemorrhagic shock due to arterio-enteric bleeding at the kidney graft site, which was diagnosed post-mortem. Conclusions In accordance with the literature, we suggest considering the removal of any rejected transplant organs in situations where arterio-enteric fistulas seem likely but cannot be excluded by repeat conventional or computed tomography-angiographic methods. Arterio-enteric fistulas may intermittently bleed over many years.

Effects of intermittent theta burst stimulation on cerebral blood flow and cerebral vasomotor reactivity.

Science.gov (United States)

Pichiorri, Floriana; Vicenzini, Edoardo; Gilio, Francesca; Giacomelli, Elena; Frasca, Vittorio; Cambieri, Chiara; Ceccanti, Marco; Di Piero, Vittorio; Inghilleri, Maurizio

2012-08-01

To determine whether intermittent theta burst stimulation influences cerebral hemodynamics, we investigated changes induced by intermittent theta burst stimulation on the middle cerebral artery cerebral blood flow velocity and vasomotor reactivity to carbon dioxide (CO(2)) in healthy participants. The middle cerebral artery flow velocity and vasomotor reactivity were monitored by continuous transcranial Doppler sonography. Changes in cortical excitability were tested by transcranial magnetic stimulation. In 11 healthy participants, before and immediately after delivering intermittent theta burst stimulation, we tested cortical excitability measured by the resting motor threshold and motor evoked potential amplitude over the stimulated hemisphere and vasomotor reactivity to CO(2) bilaterally. The blood flow velocity was monitored in both middle cerebral arteries throughout the experimental session. In a separate session, we tested the effects of sham stimulation under the same experimental conditions. Whereas the resting motor threshold remained unchanged before and after stimulation, motor evoked potential amplitudes increased significantly (P = .04). During and after stimulation, middle cerebral artery blood flow velocities also remained bilaterally unchanged, whereas vasomotor reactivity to CO(2) increased bilaterally (P = .04). The sham stimulation left all variables unchanged. The expected intermittent theta burst stimulation-induced changes in cortical excitability were not accompanied by changes in cerebral blood flow velocities; however, the bilateral increased vasomotor reactivity suggests that intermittent theta burst stimulation influences the cerebral microcirculation, possibly involving subcortical structures. These findings provide useful information on hemodynamic phenomena accompanying intermittent theta burst stimulation, which should be considered in research aimed at developing this noninvasive, low-intensity stimulation technique for safe

Intermittent fasting modulation of the diabetic syndrome in sand rats. II. In vivo investigations.

Science.gov (United States)

Belkacemi, Louiza; Selselet-Attou, Ghalem; Louchami, Karim; Sener, Abdullah; Malaisse, Willy J

2010-11-01

This study deals with the effects of daily intermittent fasting for 15 h upon the development of diabetes in sand rats exposed to a hypercaloric diet. The same pattern of daily intermittent fasting was imposed on sand rats maintained on a purely vegetal diet (control animals). Over the last 30 days of the present experiments, non-fasting animals gained weight, whilst intermittently fasting sand rats lost weight. In this respect, there was no significant difference between control animals and either diabetic or non-diabetic sand rats exposed to the hypercaloric diet. The postprandial glycemia remained fairly stable in the control animals. During a 3-week transition period from a purely vegetal to a hypercaloric diet, the post-prandial glycemia increased by 5.95 ± 1.26 mM (n=6) in diabetic sand rats, as distinct from an increase of only 0.45 ± 0.56 mM (n=6) in the non-diabetic animals. During the intermittent fasting period, the postprandial glycemia decreased significantly in the diabetic animals, but not so in the non-diabetic sand rats. Before the switch in food intake, the peak glycemia at the 30th min of an intraperitoneal glucose tolerance test was already higher in the diabetic than non-diabetic rats. In both the non-diabetic and diabetic sand rats, intermittent fasting prevented the progressive deterioration of glucose tolerance otherwise observed in non-fasting animals. These findings reveal that, at least in sand rats, intermittent daily fasting prevents the progressive deterioration of glucose tolerance otherwise taking place when these animals are exposed to a hypercaloric diet.

Transient analysis of intermittent multijet sprays

Energy Technology Data Exchange (ETDEWEB)

Panao, Miguel R.O.; Moreira, Antonio Luis N. [Universidade Tecnica de Lisboa, IN, Center for Innovation, Technology and Policy Research, Instituto Superior Tecnico, Lisboa (Portugal); Durao, Diamantino G. [Universidade Lusiada, Lisboa (Portugal)

2012-07-15

This paper analyzes the transient characteristics of intermittent sprays produced by the single-point impact of multiple cylindrical jets. The aim is to perform a transient analysis of the intermittent atomization process to study the effect of varying the number of impinging jets in the hydrodynamic mechanisms of droplet formation. The results evidence that hydrodynamic mechanisms underlying the physics of ligament fragmentation in 2-impinging jets sprays also apply to sprays produced with more than 2 jets during the main period of injection. Ligaments detaching from the liquid sheet, as well as from its bounding rim, have been identified and associated with distinct droplet clusters, which become more evident as the number of impinging jets increases. Droplets produced by detached ligaments constitute the main spray, and their axial velocity becomes more uniformly distributed with 4-impinging jets because of a delayed ligament fragmentation. Multijet spray dispersion patterns are geometric depending on the number of impinging jets. Finally, an analysis on the Weber number of droplets suggests that multijet sprays are more likely to deposit on interposed surfaces, thus becoming a promising and competitive atomization solution for improving spray cooling. (orig.)

Five-year durability of stand-alone interspinous process decompression for lumbar spinal stenosis

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Nunley PD

2017-09-01

Full Text Available Pierce D Nunley,1 Vikas V Patel,2 Douglas G Orndorff,3 William F Lavelle,4 Jon E Block,5 Fred H Geisler6 1Spine Institute of Louisiana, Shreveport, LA, 2The Spine Center, University of Colorado Hospital, Denver, CO, 3Spine Colorado, Mercy Regional Hospital, Durango, CO, 4Upstate Bone and Joint Center, East Syracuse, NY, 5Independent Consultant, San Francisco, CA, 6Independent Consultant, Chicago, IL, USA Background: Lumbar spinal stenosis is the most common indication for spine surgery in older adults. Interspinous process decompression (IPD using a stand-alone spacer that functions as an extension blocker offers a minimally invasive treatment option for intermittent neurogenic claudication associated with spinal stenosis.Methods: This study evaluated the 5-year clinical outcomes for IPD (Superion® from a randomized controlled US Food and Drug Administration (FDA noninferiority trial. Outcomes included Zurich Claudication Questionnaire (ZCQ symptom severity (ss, physical function (pf, and patient satisfaction (ps subdomains, leg and back pain visual analog scale (VAS, and Oswestry Disability Index (ODI.Results: At 5 years, 84% of patients (74 of 88 demonstrated clinical success on at least two of three ZCQ domains. Individual ZCQ domain success rates were 75% (66 of 88, 81% (71 of 88, and 90% (79 of 88 for ZCQss, ZCQpf, and ZCQps, respectively. Leg and back pain success rates were 80% (68 of 85 and 65% (55 of 85, respectively, and the success rate for ODI was 65% (57 of 88. Percentage improvements over baseline were 42%, 39%, 75%, 66%, and 58% for ZCQss, ZCQpf, leg and back pain VAS, and ODI, respectively (all P<0.001. Within-group effect sizes were classified as very large for four of five clinical outcomes (ie, >1.0; all P<0.0001. Seventy-five percent of IPD patients were free from reoperation, revision, or supplemental fixation at their index level at 5 years.Conclusion: After 5 years of follow-up, IPD with a stand-alone spacer provides

Intra-accumbens Raclopride Administration Prevents Behavioral Changes Induced by Intermittent Access to Sucrose Solution

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Josué O. Suárez-Ortiz

2018-02-01

Full Text Available Overeating is one of the most relevant clinical features in Binge Eating Disorder and in some obesity patients. According to several studies, alterations in the mesolimbic dopaminergic transmission produced by non-homeostatic feeding behavior may be associated with changes in the reward system similar to those produced by drugs of abuse. Although it is known that binge-eating is related with changes in dopaminergic transmission mediated by D2 receptors in the nucleus accumbens shell (NAcS, it has not been determined whether these receptors may be a potential target for the treatment of eating pathology with binge-eating. Accordingly, the aim of the present study was to evaluate whether sugar binging induced by intermittent access to a sucrose solution produced changes in the structure of feeding behavior and whether blocking D2 receptors prevented these changes. We used the intermittent access model to a 10% sucrose solution (2 h/day for 4 weeks to induce sugar binging in Sprague Dawley female rats. Experimental subjects consumed in a 2-h period more than 50% of the caloric intake consumed by the subjects with ad-lib access to the sweetened solution without any increase in body weight or fat accumulation. Furthermore, we evaluated whether sugar binging was associated to the estrous cycle and we did not find differences in caloric intake (estrous vs. diestrus. Subsequently, we characterized the structure of feeding behavior (microstructural analysis and the motivation for palatable food (breakpoints of the subjects with sugar binging and found that feeding episodes had short latencies, high frequencies, as well as short durations and inter-episode intervals. The intermittent access model did not increase breakpoints, as occurred in subjects with ad-lib access to the sucrose. Finally, we evaluated the effects of D2 receptor blockade in the NAcS, and found that raclopride (18 nM prevented the observed changes in the frequency and duration of

Consensus for linear multi-agent system with intermittent information transmissions using the time-scale theory

Science.gov (United States)

Taousser, Fatima; Defoort, Michael; Djemai, Mohamed

2016-01-01

This paper investigates the consensus problem for linear multi-agent system with fixed communication topology in the presence of intermittent communication using the time-scale theory. Since each agent can only obtain relative local information intermittently, the proposed consensus algorithm is based on a discontinuous local interaction rule. The interaction among agents happens at a disjoint set of continuous-time intervals. The closed-loop multi-agent system can be represented using mixed linear continuous-time and linear discrete-time models due to intermittent information transmissions. The time-scale theory provides a powerful tool to combine continuous-time and discrete-time cases and study the consensus protocol under a unified framework. Using this theory, some conditions are derived to achieve exponential consensus under intermittent information transmissions. Simulations are performed to validate the theoretical results.

Effects of acute intermittent hypoxia on glucose metabolism in awake healthy volunteers

OpenAIRE

Louis, Mariam; Punjabi, Naresh M.

2009-01-01

Accumulating evidence suggests that obstructive sleep apnea is associated with alterations in glucose metabolism. Although the pathophysiology of metabolic dysfunction in obstructive sleep apnea is not well understood, studies of murine models indicate that intermittent hypoxemia has an important contribution. However, corroborating data on the metabolic effects of intermittent hypoxia on glucose metabolism in humans are not available. Thus the primary aim of this study was to characterize th...

Intermittent Water Supplies: Challenges and Opportunities for Residential Water Users in Jordan

OpenAIRE

Rosenberg, David E.; Talozi, Samer; Lund, Jay

2008-01-01

Intermittent access to improved urban water supplies is a large and expanding global problem. This paper describes 16 supply enhancement and 23 demand management actions available to urban residential water users in Jordan to cope with intermittent supplies. We characterize actions by implementation, costs, and water quantities and qualities acquired or conserved. This effort systematically identifies potential options prior to detailed study and shows that water users have significant capaci...

Intermittent resistive faults in digital cmos circuits

NARCIS (Netherlands)

Kerkhoff, Hans G.; Ebrahimi, Hassan

2015-01-01

A major threat in extremely dependable high-end process node integrated systems in e.g. Avionics are no failures found (NFF). One category of NFFs is the intermittent resistive fault, often originating from bad (e.g. Via or TSV-based) interconnections. This paper will show the impact of these faults

Design and economical analysis of hybrid PV-wind systems connected to the grid for the intermittent production of hydrogen

International Nuclear Information System (INIS)

Dufo-Lopez, Rodolfo; Bernal-Agustin, Jose L.; Mendoza, Franklin

2009-01-01

In this paper, several designs of hybrid PV-wind (photovoltaic-wind) systems connected to the electrical grid, including the intermittent production of hydrogen, are shown. The objective considered in the design is economical to maximise the net present value (NPV) of the system. A control strategy has been applied so that hydrogen is only produced by the electrolyser when there is an excess of electrical energy that cannot be exported to the grid (intermittent production of hydrogen). Several optimisation studies based on different scenarios have been carried out. After studying the results - for systems with which the produced hydrogen would be sold for external consumption - it can be stated that the selling price of hydrogen should be about 10 Euro /kg in areas with strong wind, in order to get economically viable systems. For the hydrogen-producing systems in which hydrogen is produced when there is an excess of electricity and then stored and later used in a fuel cell to produce electricity to be sold to the grid, even in areas with high wind speed rate, the price of electrical energy produced by the fuel cell should be very high for the system to be profitable.

Intermittent balneotherapy at the Dead Sea area for patients with knee osteoarthritis.

Science.gov (United States)

Sherman, Gilad; Zeller, Lior; Avriel, Avital; Friger, Michael; Harari, Marco; Sukenik, Shaul

2009-02-01

Balneotherapy, traditionally administered during a continuous stay at the Dead Sea area, has been shown to be effective for patients suffering from knee osteoarthritis. To evaluate the effectiveness of an intermittent regimen of balneotherapy at the Dead Sea for patients with knee osteoarthritis. Forty-four patients with knee osteoarthritis were included in a prospective randomized single-blind controlled study. The patients were divided into two groups: a treatment group (n=24), which were treated twice weekly for 6 consecutive weeks in a sulfur pool heated to 35-36 degrees C, and a control group (n=20) treated in a Jacuzzi filled with tap water heated to 35-36 degrees C. Participants were assessed by the Lequesne index of osteoarthritis severity, the WOMAC index, the SF-36 quality of health questionnaire, VAS scales for pain (completed by patients and physicians), and physical examination. A statistically significant improvement, lasting up to 6 months, was observed in the treatment group for most of the clinical parameters. In the control group the only improvements were in the SF-36 bodily pain scale at 6 months, the Lequesne index at 1 month and the WOMAC pain score at the end of the treatment period. Although the patients in the control group had milder disease, the difference between the two groups was not statistically significant. Intermittent balneotherapy appears to be effective for patients with knee osteoarthritis.

Coexistence for an Almost Periodic Predator-Prey Model with Intermittent Predation Driven by Discontinuous Prey Dispersal

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Yantao Luo

2017-01-01

Full Text Available An almost periodic predator-prey model with intermittent predation and prey discontinuous dispersal is studied in this paper, which differs from the classical continuous and impulsive dispersal predator-prey models. The intermittent predation behavior of the predator species only happens in the channels between two patches where the discontinuous migration movement of the prey species occurs. Using analytic approaches and comparison theorems of the impulsive differential equations, sufficient criteria on the boundedness, permanence, and coexistence for this system are established. Finally, numerical simulations demonstrate that, for an intermittent predator-prey model, both the intermittent predation and intrinsic growth rates of the prey and predator species can greatly impact the permanence, extinction, and coexistence of the population.

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 that...

Collapse of the balloon-expandable stent in the common iliac artery due to minor external compression in a lean patient

International Nuclear Information System (INIS)

Park, Sung Eun; Choi, Ho Cheol; Choi, Dae Seob; Lee, Sang Min; Lee, Jung Eun; Cho, Su Beom; Ahn, Jong Hwa

2017-01-01

A 60-year-old lean man with claudication due to severe stenosis of the right common iliac artery (CIA) underwent balloon-expandable stent deployment. Nineteen months later, claudication and lower limb ischemia in the patient recurred after minor external pressure and computed tomography indicated collapse of the right CIA stent. We performed balloon angioplasty again and self-expandable stent deployment was performed, and the patient's symptoms were relieved. We suggest that the CIA in a lean person could be susceptible to external pressure

Design and setup of intermittent-flow respirometry system for aquatic organisms

DEFF Research Database (Denmark)

Svendsen, Morten Bo Søndergaard; Bushnell, P.G.; Steffensen, John Fleng

2016-01-01

Intermittent-flow respirometry is an experimental protocol for measuring oxygen consumption in aquatic organisms that utilizes the best features of closed (stop-flow) and flow-through respirometry while eliminating (or at least reducing) some of their inherent problems. By interspersing short...... and software further reduces error by allowing many measurements to be made over long periods thereby minimizing animal stress due to acclimation issues. This paper describes some of the fundamental principles that need to be considered when designing and carrying out automated intermittent-flow respirometry...

A meta-analysis comparing efficacy of continuous terbinafine with intermittent itraconazole for toenail onychomycosis

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Trivedi N

2010-01-01

Full Text Available Background: Toenail onychomycosis is a challenge for clinicians to treat. While both Itraconazole and terbinafine have proven to be effective against onychomycosis, very little is known about their comparative efficacy in achieving mycological and clinical cure. Aim: The purpose of this meta-analysis is to compare the efficacy of continuous terbinafine with intermittent itraconazole in the treatment of toenail onychomycosis. Material and Methods: all RCTs comparing continuous terbinafine with intermittent itraconazole were identified from PUBMED and BIDS electronic database. Results: analysis of total eight trials including 1181 patients state that treatment with continuous terbinafine is more likely to produce mycological and clinical cure compared to intermittent itraconazole with odds ratio 2.3(95% CI, 1.7 to 3.0 P< 0.0001 Conclusion: though both itraconazole and terbinafine are well tolerated and highly effective drugs, continuous terbinafine is more effective than intermittent itraconazole at achieving mycological cure of toenail onychomycosis

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.

Intermittent fasting modulates IgA levels in the small intestine under intense stress: a mouse model.

Science.gov (United States)

Lara-Padilla, Eleazar; Godínez-Victoria, Marycarmen; Drago-Serrano, Maria Elisa; Reyna-Garfias, Humberto; Arciniega-Martínez, Ivonne Maciel; Abarca-Rojano, Edgar; Cruz-Hernández, Teresita Rocío; Campos-Rodríguez, Rafael

2015-08-15

Intermittent fasting prolongs the lifespan and unlike intense stress provides health benefits. Given the role of the immunoglobulin A (IgA) in the intestinal homeostasis, the aim of this study was to assess the impact of intermittent fasting plus intense stress on secretory IgA (SIgA) production and other mucosal parameters in the duodenum and ileum. Two groups of six mice, with intermittent fasting or fed ad libitum for 12weeks, were submitted to a session of intense stress by a bout of forced swimming. Unstressed ad libitum fed or intermittently fasted groups were included as controls. After sacrifice, we evaluated intestinal SIgA and plasma adrenal hormones, lamina propria IgA+ plasma-cells, mRNA expression of polymeric immunoglobulin receptor, α- and J-chains in the liver and intestinal mucosa, as well as pro- (tumor necrosis factor-α, interleukin-6 and Interferon-γ) and anti- (interleukin-2, -4, -10 and transforming growth factor-β) inflammatory cytokines in mucosal samples. Under intense stress, intermittent fasting down- or up-modulated the levels of most parameters in the duodenum and ileum, respectively while up-regulated corticosterone levels without affecting epinephrine. Our data suggest intermittent fasting plus intense stress elicited neuroendocrine pathways that differentially controlled IgA and pIgR expression in duodenum and ileum. These findings provide experimental foundations for a presumable impact of intermittent fasting under intense stress on the intestinal homeostasis or inflammation by triggering or reducing the IgA production in ileum or duodenum respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

A qualitative descriptive study of self-management issues in people with long-term intermittent urinary catheters.

Science.gov (United States)

Wilde, Mary H; Brasch, Judith; Zhang, Yi

2011-06-01

The study was to identify and describe issues of intermittent urinary catheter users for future self-management research and/or training programmes. Limited studies were found of how people using clean intermittent catheterization manage their daily routines or troubleshoot problems. Self-management research related to intermittent catheterization could lead to improved compliance with the method and better quality of life. This qualitative descriptive study involved in-depth tape-recorded telephone interviews in 2008-2009 with 34 people in the United States of America using permanent intermittent catheterization, mostly individuals with spinal cord injury or multiple sclerosis. Recruitment was through Internet sites where individuals could link to the study website and then contact the researchers. The sample included 13 men and 21 women aged 21-72 years (mean 42 years). Content analysis for qualitative data involved iterative comparisons of transcripts, summaries and memos. Coding, key quotes and tables were developed to determine themes. Six major themes were identified: Knowing the Body, Practising Intermittent Catheterization, Limited Options in Catheters and Equipment, Inaccessible Bathrooms, Hassles, and Adjustment in Making Intermittent Catheterization a Part of Life. While some persons had choices in catheters, many did not because of insurance constraints. Some individuals developed knowledge of how to balance the procedure with fluid intake and activities. The lack of acceptable bathrooms can interfere with being able to go to work, travel or be with friends and family. All using intermittent catheterization should have adequate insurance coverage when this is needed. Research into training programmes could incorporate knowledge of experienced users. © 2011 Blackwell Publishing Ltd.

Influence of intermittent pressure, fluid flow, and mixing on the regenerative properties of articular chondrocytes.

Science.gov (United States)

Carver, S E; Heath, C A

1999-11-05

Equine articular chondrocytes, embedded within a polyglycolic acid nonwoven mesh, were cultured with various combinations of intermittent pressure, fluid flow, and mixing to examine the effects of different physical stimuli on neochondrogenesis from young cells. The cell/polymer constructs were cultured first in 125 ml spinner flasks for 1, 2, or 4 weeks and then in a perfusion system with intermittent pressure for a total of up to 6 weeks. Additional constructs were either cultured for all 6 weeks in the spinner flasks or for 1 week in spinners followed by 5 weeks in the perfusion system without intermittent pressure. Tissue constructs cultivated for 2 or 4 weeks in spinner flasks followed by perfusion with intermittent pressure had significantly higher concentrations of both sulfated glycosaminoglycan and collagen than constructs cultured entirely in spinners or almost entirely in the pressure/perfusion system. Initial cultivation in the spinner flasks, with turbulent mixing, enhanced both cell attachment and early development of the extracellular matrix. Subsequent culture with perfusion and intermittent pressure appeared to accelerate matrix formation. While the correlation was much stronger in the pressurized constructs, the compressive modulus was directly proportional to the concentration of sulfated glycosaminoglycan in all physically stressed constructs. Constructs that were not stressed beyond the 1-week seeding period lost mechanical integrity upon harvest, suggesting that physical stimulation, particularly with intermittent pressure, of immature tissue constructs during their development may contribute to their ultimate biomechanical functionality. Copyright 1999 John Wiley & Sons, Inc.

Time limit and time at VO2max' during a continuous and an intermittent run.

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Demarie, S; Koralsztein, J P; Billat, V

2000-06-01

The purpose of this study was to verify, by track field tests, whether sub-elite runners (n=15) could (i) reach their VO2max while running at v50%delta, i.e. midway between the speed associated with lactate threshold (vLAT) and that associated with maximal aerobic power (vVO2max), and (ii) if an intermittent exercise provokes a maximal and/or supra maximal oxygen consumption longer than a continuous one. Within three days, subjects underwent a multistage incremental test during which their vVO2max and vLAT were determined; they then performed two additional testing sessions, where continuous and intermittent running exercises at v50%delta were performed up to exhaustion. Subject's gas exchange and heart rate were continuously recorded by means of a telemetric apparatus. Blood samples were taken from fingertip and analysed for blood lactate concentration. In the continuous and the intermittent tests peak VO2 exceeded VO2max values, as determined during the incremental test. However in the intermittent exercise, peak VO2, time to exhaustion and time at VO2max reached significantly higher values, while blood lactate accumulation showed significantly lower values than in the continuous one. The v50%delta is sufficient to stimulate VO2max in both intermittent and continuous running. The intermittent exercise results better than the continuous one in increasing maximal aerobic power, allowing longer time at VO2max and obtaining higher peak VO2 with lower lactate accumulation.

Scaling forecast models for wind turbulence and wind turbine power intermittency

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Duran Medina, Olmo; Schmitt, Francois G.; Calif, Rudy

2017-04-01

The intermittency of the wind turbine power remains an important issue for the massive development of this renewable energy. The energy peaks injected in the electric grid produce difficulties in the energy distribution management. Hence, a correct forecast of the wind power in the short and middle term is needed due to the high unpredictability of the intermittency phenomenon. We consider a statistical approach through the analysis and characterization of stochastic fluctuations. The theoretical framework is the multifractal modelisation of wind velocity fluctuations. Here, we consider three wind turbine data where two possess a direct drive technology. Those turbines are producing energy in real exploitation conditions and allow to test our forecast models of power production at a different time horizons. Two forecast models were developed based on two physical principles observed in the wind and the power time series: the scaling properties on the one hand and the intermittency in the wind power increments on the other. The first tool is related to the intermittency through a multifractal lognormal fit of the power fluctuations. The second tool is based on an analogy of the power scaling properties with a fractional brownian motion. Indeed, an inner long-term memory is found in both time series. Both models show encouraging results since a correct tendency of the signal is respected over different time scales. Those tools are first steps to a search of efficient forecasting approaches for grid adaptation facing the wind energy fluctuations.

Analyzing energy consumption while heating one-layer building envelopes in conditions of intermittent heating

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Vytchikov Yury

2017-01-01

Full Text Available This paper focuses on energy consumption for heating single layer building envelopes, used in conditions of intermittent heating in different physical and mechanical and thermophysical parameters of construction materials. The authors investigated several variants of single-layer building envelopes, used frequently in building practice, with different density and coefficients of building materials thermal conductivity. For each variant of a building envelope heat leakage and time spent on heating were calculated. Heating time was calculated by both exact and approximate analytical method. Then the researchers draw a graphic dependence of energy consumption on the density of the material taking this computational data as a basis. Further analysis showed that building envelopes made of lightweight aggregate concrete and porous concrete were the most energy efficient.This paper focuses on energy consumption for heating single layer building envelopes, used in conditions of intermittent heating in different physical and mechanical and thermophysical parameters of construction materials. The authors investigated several variants of single-layer building envelopes, used frequently in building practice, with different density and coefficients of building materials thermal conductivity. For each variant of a building envelope heat leakage and time spent on heating were calculated. Heating time was calculated by both exact and approximate analytical method. Then the researchers draw a graphic dependence of energy consumption on the density of the material taking this computational data as a basis. Further analysis showed that building envelopes made of lightweight aggregate concrete and porous concrete were the most energy efficient.

On the moment-order, multiplicity and transverse-momentum dependences of intermittency in hadron-hadron collisions

International Nuclear Information System (INIS)

Wu Yuanfang; Liu Lianshou

1991-01-01

The dependences of intermittency degree on moment-order, multiplicity and transverse momentum are discussed. It is pointed out that the difference between the dependences of the anomalous exponents of factorial moments on moment-order at energies lower and higher than top ISR energy implies that the dependences of intermittency degree on multiplicity are in opposite directions in the two energy regions. It is argued that these different trends imply that intermittency degree depends on other more basic quantity, such as transverse momentum. These assertions and their deductions remain to be examined experimentally

Aortofemoral thromboendarterectomy

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Aguiar Eduardo Toledo de

2002-01-01

Full Text Available PURPOSE: To study whether endarterectomy is feasible in all patients with aortofemoral atherosclerotic obstruction, considering early and late results. METHODS: A clinical, prospective, and descriptive study carried out in a university hospital. Inclusion criteria were atherosclerotic aortofemoral obstructive disease, clinical status compatible with major surgery, and absence of prior restorative procedure. Exclusion criteria were aneurysm, inflammatory arterial disease, and prior restorative procedure found during surgery. Eighty patients entered the protocol, but 9 were excluded (11.2%. Seventy-one patients, mean age of 57.3 years, underwent endarterectomy. Operative indications were intermittent claudication and critical ischemia. A ring-stripper endarterectomy technique was employed in all patients. Results were related to age, gender, symptoms, presence of diabetes mellitus, extension of endarterectomy, and extent of obstructive disease. Chi square or Fisher exact tests were used when appropriate, and the Wilkoxon (Gehan test was used to compare survival curves. RESULTS: Sixty-eight (100% endarterectomies were patent at discharge. The mortality rate was 4.2%. The amputation rate (4.3% was higher in diabetic patients and when there was associated femoropopliteal obstruction. The 5-year survival rate was 83.3%, and late deaths were mostly cardiovascular. Diabetes mellitus, age above 65 years, and associated femoropopliteal obstruction lowered the survival rate. The 5-year patency rate was 87.0%. Critical ischemia and less extensive endarterectomies were associated with a lower patency rate. There were no anastomotic aneurysms or deep infections. CONCLUSIONS: Aortofemoral thromboendarterectomy is feasible in 90% of patients, early mortality rate is low, diabetic patients and those with associated femoropopliteal obstructive disease have a higher mortality rate, amputation rate is low, late deaths are mostly cardiovascular, and late patency

Peripheral arterial disease among adult diabetic patients attending a large outpatient diabetic clinic at a national referral hospital in Uganda: a descriptive cross sectional study.

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Raymond Mbayo Mwebaze

Full Text Available BACKGROUND: Peripheral arterial disease (PAD is one of the recognised diabetic macro vascular complications. It is a marker of generalised systemic atherosclerosis and is closely associated with symptomatic coronary and cerebrovascular disease, hence significant morbidity and mortality. Among African adult diabetic populations, screening and diagnosis of PAD is frequently suboptimal. The aim of this study was to determine the prevalence and associated clinical factors of PAD in adult ambulatory diabetic patients attending the outpatient diabetic clinic of Mulago national referral and teaching hospital, Kampala Uganda. METHODS: In this descriptive cross sectional study, 146 ambulatory adult diabetic patients were studied. Information about their socio-demographic and clinical characteristics, fasting lipid profile status, blood pressure, glycated haemoglobin (HbA1c levels and presence of albuminuria was collected using a pre tested questionnaire. Measurement of ankle brachial index (ABI to assess for PAD, defined as a ratio less than 0.9 was performed using a portable 5-10 MHz Doppler device. Clinical factors associated with PAD were determined by comparing specific selected characteristics in patients with PAD and those without. RESULTS: The mean age/standard deviation of the study participants was 53.9/12.4 years with a male predominance (75, 51.4%. PAD was prevalent in 57 (39% study participants. Of these, 34 (59.6% had symptomatic PAD. The noted clinical factors associated with PAD in this study population were presence of symptoms of intermittent claudication and microalbuminuria. CONCLUSIONS: This study documents a high prevalence of PAD among adult ambulatory Ugandan diabetic patients. Aggressive screening for PAD using ABI measurement in adult diabetic patients should be emphasised in Uganda especially in the presence of symptoms of intermittent claudication and microalbuminuria.

Intermittency patterns in pp collisions at 360 GeV/c

International Nuclear Information System (INIS)

Singh, J.B.; Kohli, J.M.

1991-01-01

The intermittency effect has been observed in pp collisions at 360 GeV/c and the strength decreases with the increase in multiplicity. The low multiplicity events in pp data (n ch ≤ 8), anti pp collisions (n ch ≤ 15) at Collider energy and elementary interaction (e + e - , μp) samples have almost the same strength. Most likely, few sources seem to contribute at lower multiplications. The intermittency effect is less in pp data compared to e + e - data, however it is fairly strong as compared to nucleus data. The presently used hadronization models DPM, LUND and FRITIOF do not reproduce the results fully. (orig.)

Crisis induced intermittency in a fourth-order autonomous electric circuit

International Nuclear Information System (INIS)

Stouboulos, I.N.; Miliou, A.N.; Valaristos, A.P.; Kyprianidis, I.M.; Anagnostopoulos, A.N.

2007-01-01

The chaotic dynamics of a fourth-order autonomous nonlinear electric circuit has been studied. The circuit consists of two active elements, one linear negative conductance and one nonlinear resistor exhibiting a symmetrical piecewise-linear v-i characteristic and two capacitances C 1 and C 2 , which serve as the control parameters of the system. Experimental time series and the corresponding phase portraits were used to register the intermittent behaviour of the corresponding dynamical system between two interacting subattractors. The distribution of the times τ, between successive transitions from the one subattractor to the other indicates that a crisis induced intermittency occurs in the studied circuit

Outer synchronization of complex networks with internal delay and coupling delay via aperiodically intermittent pinning control

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Zhang, Chuan; Wang, Xingyuan; Wang, Chunpeng; Xia, Zhiqiu

This paper concerns the outer synchronization problem between two complex delayed networks via the method of aperiodically intermittent pinning control. Apart from previous works, internal delay and coupling delay are both involved in this model, and the designed intermittent controllers can be aperiodic. The main work in this paper can be summarized as follows: First, two cases of aperiodically intermittent control with constant gain and adaptive gain are implemented, respectively. The intermittent control and pinning control are combined to reduce consumptions further. Then, based on the Lyapunov stability theory, synchronization protocols are given by strict derivation. Especially, the designed controllers are indeed simple and valid in application of theory to practice. Finally, numerical examples put the proposed control methods to the test.

Thermal responses from repeated exposures to severe cold with intermittent warmer temperatures.

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Ozaki, H; Enomoto-Koshimizu, H; Tochihara, Y; Nakamura, K

1998-09-01

This study was conducted to evaluate physiological reaction and manual performance during exposure to warm (30 degrees C) and cool (10 degrees C) environments after exposure to very low temperatures (-25 degrees C). Furthermore, this experiment was conducted to study whether it is desirable to remove cold-protective jackets in warmer rooms after severe cold exposure. Eight male students remained in an extremely cold room for 20 min, after which they transferred into either the warm room or the cool room for 20 min. This pattern was repeated three times, and the total cold exposure time was 60 min. In the warm and cool rooms, the subjects either removed their cold-protective jackets (Condition A), or wore them continuously (Condition B). Rectal temperature, skin temperatures, manual performance, blood pressure, thermal, comfort and pain sensations were measured during the experiment. The effects of severe cold on almost all measurements in the cool (10 degrees C) environment were greater than those in the warm (30 degrees C) environment under both clothing conditions. The effects of severe cold on all measurements under Condition A except rectal temperature and toe skin temperature were significantly greater than those under Condition B in the cool environment but, not at all differences between Condition A and Condition B in the warm environments were significant. It was recognized that to remove cold-protective jackets in the cool room (10 degrees C) after severe cold exposure promoted the effects of severe cold. When rewarming in the warm resting room (30 degrees C), the physiological and psychological responses and manual performance were not influenced by the presence or absence of cold-protective clothing. These results suggest that it is necessary for workers to make sure to rewarm in the warm room outside of the cold storage and continue to wear cold-protective clothing in the cool room.

Impact of intermittent fasting on glucose homeostasis.

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Varady, Krista A

2016-07-01

This article provides an overview of the most recent human trials that have examined the impact of intermittent fasting on glucose homeostasis. Our literature search retrieved one human trial of alternate day fasting, and three trials of Ramadan fasting published in the past 12 months. Current evidence suggests that 8 weeks of alternate day fasting that produces mild weight loss (4% from baseline) has no effect on glucose homeostasis. As for Ramadan fasting, decreases in fasting glucose, insulin, and insulin resistance have been noted after 4 weeks in healthy normal weight individuals with mild weight loss (1-2% from baseline). However, Ramadan fasting may have little impact on glucoregulatory parameters in women with polycystic ovarian syndrome who failed to observe weight loss. Whether intermittent fasting is an effective means of regulating glucose homeostasis remains unclear because of the scarcity of studies in this area. Large-scale, longer-term randomized controlled trials will be required before the use of fasting can be recommended for the prevention and treatment of metabolic diseases.

Intermittent magnetic reconnection in TS-3 merging experiment

International Nuclear Information System (INIS)

Ono, Y.; Hayashi, Y.; Ii, T.; Tanabe, H.; Ito, S.; Kuwahata, A.; Ito, T.; Kamino, Y.; Yamada, T.; Inomoto, M.

2011-01-01

Ejection of current sheet with plasma mass causes impulsive and intermittent magnetic reconnection in the TS-3 spherical tokamak (ST) merging experiment. Under high guide toroidal field, the sheet resistivity is almost classical due to the sheet thickness much longer than the ion gyroradius. Large inflow flux and low current-sheet resistivity result in flux and plasma pileup followed by rapid growth of the current sheet. When the pileup exceeds a critical limit, the sheet is ejected mechanically from the squeezed X-point area. The reconnection (outflow) speed is slow during the flux/plasma pileup and is fast during the ejection, suggesting that intermittent reconnection similar to the solar flare increases the averaged reconnection speed. These transient effects enable the merging tokamaks to have the fast reconnection as well as the high-power reconnection heating, even when their current-sheet resistivity is low under high guide field.

The Comparison of Continuous and Intermittent Enteral Nutrition In Cerebrovascular Patients

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Levent Güngör

2011-06-01

Full Text Available OBJECTIVE: Dysphagia and malnutrition are not so rare in stroke patients, and have an unfavorable influence on recovery. Nutritional support may reduce infections, duration of hospital stay and mortality. However, there is no clear evidence about the modality of nasogastric nutrition. In this study, intermittent and continuous enteral nutrition is compared by means of pulmonary infections and gastrointestinal tolerance, among acute cerebrovascular patients. METHODS: Sixty two acute cerebrovascular patients with dysphagia were included the study. The same volume of nutrition product was infused 4 times daily to 31 patients, and continuously for 24 hours to the remaining 31. After 10 days of follow-up, the rates of pulmonary infections, diarrhea, increased gastric residual volumes, vomiting and tube occlusion were compared between two groups. RESULTS: Twenty patients developed pneumonia (32% and 8 diarrhea (13%. Mortality due to complications associated with tube feeding was 6%. Aspiration and related pneumonia was present in 11 patients in the intermittent nutrition group (35%, and in 9 patients in the continuous nutrition group (29%. The rate of pulmonary infection was not statistically different between two groups (p>0.05. Diarrhea was observed in 7 intermittently fed patients (23%, while was present only in 1 patient (3% in the continuously fed group. Diarrhea was more common in the intermittent nutrition group, just at the statistical border (p=0.05. None of the patients developed tube occlusion, vomiting and gastric retention. The rate of mortality and the interruption of feeding was not significantly different between two groups (p>0.05. CONCLUSION: Diarrhea and pulmonary infections are more prevalent with intermittent tube feeding with respect to continuous enteral nutrition, though the difference is not so conspicuous. The reason may be contamination of the equipments and the feeding solution because of frequent manipulation and

The Comparison of Continuous and Intermittent Enteral Nutrition In Cerebrovascular Patients

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Levent Güngör

2011-06-01

Full Text Available OBJECTIVE: Dysphagia and malnutrition are not so rare in stroke patients, and have an unfavorable influence on recovery. Nutritional support may reduce infections, duration of hospital stay and mortality. However, there is no clear evidence about the modality of nasogastric nutrition. In this study, intermittent and continuous enteral nutrition is compared by means of pulmonary infections and gastrointestinal tolerance, among acute cerebrovascular patients. METHODS: Sixty two acute cerebrovascular patients with dysphagia were included the study. The same volume of nutrition product was infused 4 times daily to 31 patients, and continuously for 24 hours to the remaining 31. After 10 days of follow-up, the rates of pulmonary infections, diarrhea, increased gastric residual volumes, vomiting and tube occlusion were compared between two groups. RESULTS: Twenty patients developed pneumonia (32% and 8 diarrhea (13%. Mortality due to complications associated with tube feeding was 6%. Aspiration and related pneumonia was present in 11 patients in the intermittent nutrition group (35%, and in 9 patients in the continuous nutrition group (29%. The rate of pulmonary infection was not statistically different between two groups (p>0.05. Diarrhea was observed in 7 intermittently fed patients (23%, while was present only in 1 patient (3% in the continuously fed group. Diarrhea was more common in the intermittent nutrition group, just at the statistical border (p=0.05. None of the patients developed tube occlusion, vomiting and gastric retention. The rate of mortality and the interruption of feeding was not significantly different between two groups (p>0.05. CONCLUSION: Diarrhea and pulmonary infections are more prevalent with intermittent tube feeding with respect to continuous enteral nutrition, though the difference is not so conspicuous. The reason may be contamination of the equipments and the feeding solution because of frequent manipulation and

Seizure tests distinguish intermittent fasting from the ketogenic diet

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Hartman, Adam L.; Zheng, Xiangrong; Bergbower, Emily; Kennedy, Michiko; Hardwick, J. Marie

2010-01-01

Summary Purpose Calorie restriction can be anticonvulsant in animal models. The ketogenic diet was designed to mimic calorie restriction and has been assumed to work by the same mechanisms. We challenged this assumption by profiling the effects of these dietary regimens in mice subjected to a battery of acute seizure tests. Methods Juvenile male NIH Swiss mice received ketogenic diet or a normal diet fed in restricted quantities (continuously or intermittently) for ~ 12 days, starting at 3–4 weeks of age. Seizures were induced by the 6 Hz test, kainic acid, maximal electroshock, or pentylenetetrazol. Results The ketogenic and calorie-restricted diets often had opposite effects depending on the seizure test. The ketogenic diet protected from 6 Hz–induced seizures, whereas calorie restriction (daily and intermittent) increased seizure activity. Conversely, calorie restriction protected juvenile mice against seizures induced by kainic acid, whereas the ketogenic diet failed to protect. Intermittent caloric restriction worsened seizures induced by maximal electroshock but had no effect on those induced by pentylenetetrazol. Discussion In contrast to a longstanding hypothesis, calorie restriction and the ketogenic diet differ in their acute seizure test profiles, suggesting that they have different underlying anticonvulsant mechanisms. These findings highlight the importance of the 6 Hz test and its ability to reflect the benefits of ketosis and fat consumption. PMID:20477852

Seizure tests distinguish intermittent fasting from the ketogenic diet.

Science.gov (United States)

Hartman, Adam L; Zheng, Xiangrong; Bergbower, Emily; Kennedy, Michiko; Hardwick, J Marie

2010-08-01

Calorie restriction can be anticonvulsant in animal models. The ketogenic diet was designed to mimic calorie restriction and has been assumed to work by the same mechanisms. We challenged this assumption by profiling the effects of these dietary regimens in mice subjected to a battery of acute seizure tests. Juvenile male NIH Swiss mice received ketogenic diet or a normal diet fed in restricted quantities (continuously or intermittently) for ∼12 days, starting at 3-4 weeks of age. Seizures were induced by the 6 Hz test, kainic acid, maximal electroshock, or pentylenetetrazol. The ketogenic and calorie-restricted diets often had opposite effects depending on the seizure test. The ketogenic diet protected from 6 Hz-induced seizures, whereas calorie restriction (daily and intermittent) increased seizure activity. Conversely, calorie restriction protected juvenile mice against seizures induced by kainic acid, whereas the ketogenic diet failed to protect. Intermittent caloric restriction worsened seizures induced by maximal electroshock but had no effect on those induced by pentylenetetrazol. In contrast to a longstanding hypothesis, calorie restriction and the ketogenic diet differ in their acute seizure test profiles, suggesting that they have different underlying anticonvulsant mechanisms. These findings highlight the importance of the 6 Hz test and its ability to reflect the benefits of ketosis and fat consumption. Wiley Periodicals, Inc. © 2010 International League Against Epilepsy.

Implementation of DMAs in Intermittent Water Supply Networks Based on Equity Criteria

OpenAIRE

Amilkar E. Ilaya-Ayza; Carlos Martins; Enrique Campbell; Joaquín Izquierdo

2017-01-01

Intermittent supply is a common way of delivering water in many developing countries. Limitations on water and economic resources, in addition to poor management and population growth, limit the possibilities of delivering water 24 h a day. Intermittent water supply networks are usually designed and managed in an empirical manner, or using tools and criteria devised for continuous supply systems, and this approach can produce supply inequity. In this paper, an approach based on the hydraulic ...

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.

Intermittency and transition to chaos in the cubical lid-driven cavity flow

Energy Technology Data Exchange (ETDEWEB)

Loiseau, J-Ch [Department of Mechanics, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden); Robinet, J-Ch [Laboratoire DynFluid, Arts et Métiers ParisTech, F-75013 Paris (France); Leriche, E, E-mail: loiseau@mech.kth.se [Laboratoire de Mécanique de Lille, Université Lille 1, F-59655 Villeneuve d’Ascq (France)

2016-12-15

Transition from steady state to intermittent chaos in the cubical lid-driven cavity flow is investigated numerically. Fully three-dimensional stability analyses have revealed that the flow experiences an Andronov–Poincaré–Hopf bifurcation at a critical Reynolds number Re {sub c} = 1914. As for the 2D-periodic lid-driven cavity flows, the unstable mode originates from a centrifugal instability of the primary vortex core. A Reynolds–Orr analysis reveals that the unstable perturbation relies on a combination of the lift-up and anti lift-up mechanisms to extract its energy from the base flow. Once linearly unstable, direct numerical simulations show that the flow is driven toward a primary limit cycle before eventually exhibiting intermittent chaotic dynamics. Though only one eigenpair of the linearized Navier–Stokes operator is unstable, the dynamics during the intermittencies are surprisingly well characterized by one of the stable eigenpairs. (paper)

Intermittent aerosol delivery to the lungs during high-flow nasal cannula therapy.

Science.gov (United States)

Golshahi, Laleh; Longest, P Worth; Azimi, Mandana; Syed, Aamer; Hindle, Michael

2014-10-01

Use of submicrometer particles combined with condensational growth techniques has been proposed to reduce drug losses within components of high-flow nasal cannula therapy systems and to enhance the dose reaching the lower respiratory tract. These methods have been evaluated using continuous inhalation flow rather than realistic inhalation/exhalation breathing cycles. The goal of this study was to evaluate in vitro aerosol drug delivery using condensational growth techniques during high-flow nasal cannula therapy using realistic breathing profiles and incorporating intermittent aerosol delivery techniques. A mixer-heater combined with a vibrating mesh nebulizer was used to generate a submicrometer aerosol using a formulation of 0.2% albuterol sulfate and 0.2% sodium chloride in water. Delivery efficiency of the aerosol for 1 min through a nasal cannula was considered using an intermittent delivery regime with aerosol being emitted for either the entire inhalation time (2 s) or half of the inhalation period (1 s) and compared with continuous delivery. The deposition of the aerosol was evaluated in the nasal delivery components (ventilator tubing and cannula) and an in vitro adult nose-mouth-throat (NMT) model using 3 realistic breathing profiles. Significant improvements in dose delivered to the exit of the NMT model (ex-NMT) were observed for both condensational growth methods using intermittent aerosol delivery compared with continuous delivery, and increasing the tidal volume was found useful. The combination of the largest tidal volume with the shortest intermittent delivery time resulted in the lowest respiration losses and the highest ex-NMT delivered dose. Intermittent aerosol delivery using realistic breathing profiles of submicrometer condensational growth aerosols was found to be efficient in delivering nasally administered drugs in an in vitro airway model. Copyright © 2014 by Daedalus Enterprises.

Uncoupling protein-2 mRNA expression in mice subjected to intermittent hypoxia

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Luciana Rodrigues Vieira

2015-04-01

Full Text Available Objective: To investigate the effect of intermittent hypoxia-a model of obstructive sleep apnea (OSA-on pancreatic expression of uncoupling protein-2 (UCP2, as well as on glycemic and lipid profiles, in C57BL mice. Methods: For 8 h/day over a 35-day period, male C57BL mice were exposed to intermittent hypoxia (hypoxia group or to a sham procedure (normoxia group. The intermittent hypoxia condition involved exposing mice to an atmosphere of 92% N and 8% CO2 for 30 s, progressively reducing the fraction of inspired oxygen to 8 ± 1%, after which they were exposed to room air for 30 s and the cycle was repeated (480 cycles over the 8-h experimental period. Pancreases were dissected to isolate the islets. Real-time PCR was performed with TaqMan assays. Results: Expression of UCP2 mRNA in pancreatic islets was 20% higher in the normoxia group than in the hypoxia group (p = 0.11. Fasting serum insulin was higher in the hypoxia group than in the normoxia group (p = 0.01. The homeostasis model assessment of insulin resistance indicated that, in comparison with the control mice, the mice exposed to intermittent hypoxia showed 15% lower insulin resistance (p = 0.09 and 21% higher pancreatic β-cell function (p = 0.01. Immunohistochemical staining of the islets showed no significant differences between the two groups in terms of the area or intensity of α- and β-cell staining for insulin and glucagon. Conclusions: To our knowledge, this is the first report of the effect of intermittent hypoxia on UCP2 expression. Our findings suggest that UCP2 regulates insulin production in OSA. Further study of the role that UCP2 plays in the glycemic control of OSA patients is warranted.

The Acute Effects of Intermittent Light Exposure in the Evening on Alertness and Subsequent Sleep Architecture.

Science.gov (United States)

Yang, Minqi; Ma, Ning; Zhu, Yingying; Su, Ying-Chu; Chen, Qingwei; Hsiao, Fan-Chi; Ji, Yanran; Yang, Chien-Ming; Zhou, Guofu

2018-03-15

Exposure to bright light is typically intermittent in our daily life. However, the acute effects of intermittent light on alertness and sleep have seldom been explored. To investigate this issue, we employed within-subject design and compared the effects of three light conditions: intermittent bright light (30-min pulse of blue-enriched bright light (~1000 lux, ~6000 K) alternating with 30-min dim normal light (~5 lux, ~3600 K) three times); continuous bright light; and continuous dim light on subjective and objective alertness and subsequent sleep structure. Each light exposure was conducted during the three hours before bedtime. Fifteen healthy volunteers (20 ± 3.4 years; seven males) were scheduled to stay in the sleep laboratory for four separated nights (one for adaptation and the others for the light exposures) with a period of at least one week between nights. The results showed that when compared with dim light, both intermittent light and continuous bright light significantly increased subjective alertness and decreased sleep efficiency (SE) and total sleep time (TST). Intermittent light significantly increased objective alertness than dim light did during the second half of the light-exposure period. Our results suggested that intermittent light was as effective as continuous bright light in their acute effects in enhancing subjective and objective alertness and in negatively impacting subsequent sleep.

The Acute Effects of Intermittent Light Exposure in the Evening on Alertness and Subsequent Sleep Architecture

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Minqi Yang

2018-03-01

Full Text Available Exposure to bright light is typically intermittent in our daily life. However, the acute effects of intermittent light on alertness and sleep have seldom been explored. To investigate this issue, we employed within-subject design and compared the effects of three light conditions: intermittent bright light (30-min pulse of blue-enriched bright light (~1000 lux, ~6000 K alternating with 30-min dim normal light (~5 lux, ~3600 K three times; continuous bright light; and continuous dim light on subjective and objective alertness and subsequent sleep structure. Each light exposure was conducted during the three hours before bedtime. Fifteen healthy volunteers (20 ± 3.4 years; seven males were scheduled to stay in the sleep laboratory for four separated nights (one for adaptation and the others for the light exposures with a period of at least one week between nights. The results showed that when compared with dim light, both intermittent light and continuous bright light significantly increased subjective alertness and decreased sleep efficiency (SE and total sleep time (TST. Intermittent light significantly increased objective alertness than dim light did during the second half of the light-exposure period. Our results suggested that intermittent light was as effective as continuous bright light in their acute effects in enhancing subjective and objective alertness and in negatively impacting subsequent sleep.

The effect of intermittent fasting on blood pressure variability in patients with newly diagnosed hypertension or prehypertension.

Science.gov (United States)

Erdem, Yunus; Özkan, Gülsüm; Ulusoy, Şükrü; Arıcı, Mustafa; Derici, Ülver; Şengül, Şule; Sindel, Şükrü; Ertürk, Şehsuvar

2018-01-01

Intermittent fasting is a phenomenon which can be observed in most humans. The effect of intermittent fasting on blood pressure variability (BPV) has not previously been investigated. The purpose of this study was to assess the effect of fasting on blood pressure (BP) (with office, home, central, and ambulatory blood pressure monitoring [ABPM]) and on BPV. Sixty individuals were included in the study. Office, home, ABPM, and central BP measurements were performed before and during intermittent fasting. Standard deviation and coefficient variation were used for office and home BPV measurement, while the smoothness index was used to calculate ABPM variability. Patients' BP and BPV values before and during intermittent fasting were then compared. Intermittent fasting resulted in a significant decrease in office BP values and ABPM measurements but caused no significant change in home and central BP measurements. Twenty-four hour urinary sodium excretion decreased. Smoothness values obtained from ABPM measurements were low; in other words, BPV was greater. BPV was higher in patients who woke up to eat before sunrise, but BPV was low in patients with high body mass index. Intermittent fasting produced a significant decrease in BP values in terms of office and ABPM measurements in this study but caused no significant change in central BP and home measurements. We also identified an increase in BPV during intermittent fasting, particularly in patients who rose before sunrise. Copyright © 2017 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.

Multi-point observations of intermittency in the cusp regions

Directory of Open Access Journals (Sweden)

M. M. Echim

2007-08-01

Full Text Available In this paper we investigate the statistical properties of magnetic field fluctuations measured by the four Cluster spacecraft in the cusp and close to the interface with the magnetospheric lobes, magnetopause and magnetosheath. At lower altitudes along the outbound orbit of 26 February 2001, the magnetic field fluctuations recorded by all four spacecraft are random and their Probability Distribution Functions (PDFs are Gaussian at all scales. The flatness parameter, F – related to the kurtosis of the time series, is equal to 3. At higher altitudes, in the cusp and its vicinity, closer to the interface with the magnetopause and magnetosheath, the PDFs from all Cluster satellites are non-Gaussian and show a clear intermittent behavior at scales smaller than τ_G≈ 61 s (or 170 km. The flatness parameter increases to values greater than 3 for scales smaller than τ_G. A Haar wavelet transform enables the identification of the "events" that produce sudden variations of the magnetic field and of the scales that have most of the power. The LIM parameter (i.e. normalized wavelet power indicates that events for scales below 65 s are non-uniformly distributed throughout the cusp passage. PDFs, flatness and wavelet analysis show that at coarse-grained scales larger than τ_G the intermittency is absent in the cusp. Fluctuations of the magnetic energy observed during the same orbit in the magnetosheath show PDFs that tend toward a Gaussian at scales smaller than τ_G found in the cusp. The flatness analysis confirms the decreasing of τ_G from cusp to magnetosheath. Our analysis reveals the turbulent cusp as a transition region from a non-intermittent turbulent state inside the magnetosphere to an intermittent turbulent state in the magnetosheath that has statistical properties resembling the solar wind turbulence. The observed turbulent fluctuations in the cusp suggests a phenomenon of nonlinear

Exposure to intermittent hypoxia and sustained hypercapnia reduces therapeutic CPAP in participants with obstructive sleep apnea.

Science.gov (United States)

El-Chami, Mohamad; Sudan, Sukhesh; Lin, Ho-Sheng; Mateika, Jason H

2017-10-01

Our purpose was to determine whether exposure to mild intermittent hypoxia leads to a reduction in the therapeutic continuous positive airway pressure required to eliminate breathing events. Ten male participants were treated with twelve 2-min episodes of hypoxia ([Formula: see text] ≈50 mmHg) separated by 2-min intervals of normoxia in the presence of [Formula: see text] that was sustained 3 mmHg above baseline. During recovery from the last episode, the positive airway pressure was reduced in a stepwise fashion until flow limitation was evident. The participants also completed a sham protocol under normocapnic conditions, which mimicked the time frame of the intermittent hypoxia protocol. After exposure to intermittent hypoxia, the therapeutic pressure was significantly reduced (i.e., 5 cmH 2 O) without evidence of flow limitation (103.4 ± 6.3% of baseline, P = 0.5) or increases in upper airway resistance (95.6 ± 15.0% of baseline, P = 0.6). In contrast, a similar decrease in pressure was accompanied by flow limitation (77.0 ± 1.8% of baseline, P = 0.001) and an increase in upper airway resistance (167.2 ± 17.5% of baseline, P = 0.01) after the sham protocol. Consistent with the initiation of long-term facilitation of upper airway muscle activity, exposure to intermittent hypoxia reduced the therapeutic pressure required to eliminate apneic events that could improve treatment compliance. This possibility, coupled with the potentially beneficial effects of intermittent hypoxia on comorbidities linked to sleep apnea, suggests that mild intermittent hypoxia may have a multipronged therapeutic effect on sleep apnea. NEW & NOTEWORTHY Our new finding is that exposure to mild intermittent hypoxia reduced the therapeutic pressure required to treat sleep apnea. These findings are consistent with previous results, which have shown that long-term facilitation of upper muscle activity can be initiated following exposure to intermittent hypoxia in humans.

Spectral degeneracy and escape dynamics for intermittent maps with a hole

International Nuclear Information System (INIS)

Froyland, Gary; Stancevic, Ognjen; Murray, Rua

2011-01-01

We study intermittent maps from the point of view of metastability. Small neighbourhoods of an intermittent fixed point and their complements form pairs of almost-invariant sets. Treating the small neighbourhood as a hole, we first show that the absolutely continuous conditional invariant measures (ACCIMs) converge to the ACIM as the length of the small neighbourhood shrinks to zero. We then quantify how the escape dynamics from these almost-invariant sets are connected with the second eigenfunctions of Perron–Frobenius (transfer) operators when a small perturbation is applied near the intermittent fixed point. In particular, we describe precisely the scaling of the second eigenvalue with the perturbation size, provide upper and lower bounds and demonstrate L 1 convergence of the positive part of the second eigenfunction to the ACIM as the perturbation goes to zero. This perturbation and associated eigenvalue scalings and convergence results are all compatible with Ulam's method and provide a formal explanation for the numerical behaviour of Ulam's method in this nonuniformly hyperbolic setting. The main results of the paper are illustrated with numerical computations

Canonical Cortical Circuit Model Explains Rivalry, Intermittent Rivalry, and Rivalry Memory.

Directory of Open Access Journals (Sweden)

Shashaank Vattikuti

2016-05-01

Full Text Available It has been shown that the same canonical cortical circuit model with mutual inhibition and a fatigue process can explain perceptual rivalry and other neurophysiological responses to a range of static stimuli. However, it has been proposed that this model cannot explain responses to dynamic inputs such as found in intermittent rivalry and rivalry memory, where maintenance of a percept when the stimulus is absent is required. This challenges the universality of the basic canonical cortical circuit. Here, we show that by including an overlooked realistic small nonspecific background neural activity, the same basic model can reproduce intermittent rivalry and rivalry memory without compromising static rivalry and other cortical phenomena. The background activity induces a mutual-inhibition mechanism for short-term memory, which is robust to noise and where fine-tuning of recurrent excitation or inclusion of sub-threshold currents or synaptic facilitation is unnecessary. We prove existence conditions for the mechanism and show that it can explain experimental results from the quartet apparent motion illusion, which is a prototypical intermittent rivalry stimulus.

Collapse of the balloon-expandable stent in the common iliac artery due to minor external compression in a lean patient

Energy Technology Data Exchange (ETDEWEB)

Park, Sung Eun; Choi, Ho Cheol; Choi, Dae Seob; Lee, Sang Min; Lee, Jung Eun [Gyeongsang National University School of Medicine and Gyeongsang National University Hospital, Jinju (Korea, Republic of); Cho, Su Beom; Ahn, Jong Hwa [Gyeongsang National University School of Medicine and Gyeongsang National University Changwon Hospital, Changwon (Korea, Republic of)

2017-08-15

A 60-year-old lean man with claudication due to severe stenosis of the right common iliac artery (CIA) underwent balloon-expandable stent deployment. Nineteen months later, claudication and lower limb ischemia in the patient recurred after minor external pressure and computed tomography indicated collapse of the right CIA stent. We performed balloon angioplasty again and self-expandable stent deployment was performed, and the patient's symptoms were relieved. We suggest that the CIA in a lean person could be susceptible to external pressure.

Whole lung lavage with intermittent double lung ventilation. A modified technique for managing pulmonary alveolar proteinosis

International Nuclear Information System (INIS)

Ahmed, Raees; Iqbal, Mobeen; Kashef, Sayed H.; Almomatten, Mohammed I.

2005-01-01

Whole lung lavage is still the most effective treatment for pulmonary alveolar proteinosis. We report a 21-year-old male diagnosed with pulmonary alveolar proteinosis by open lung biopsy and who underwent whole lung lavage with a modified technique. He showed significant improvement in clinical and functional parameters. The technique of intermittent double lung ventilation during lavage procedure keeps the oxygen saturation in acceptable limits in patients at risk for severe hypoxemia and allows the procedure to be completed in a single setting. (author)

Modeling and Optimization for Management of Intermittent Water Supply

Science.gov (United States)

Lieb, A. M.; Wilkening, J.; Rycroft, C.

2014-12-01

In many urban areas, 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. These consequences include degradation of distribution system components, compromised water quality, and inequitable water availability. The goal of this work is to model the important dynamics and identify operating conditions that mitigate certain negative effects of intermittent water supply. Specifically, we will look at controlling valve parameters occurring as boundary conditions in a network model of transient, transition flow through closed pipes. Gradient-based optimization will be used to find boundary values to minimize pressure gradients and ensure equitable water availability at system endpoints.

Long-range forecasting of intermittent streamflow

OpenAIRE

F. F. van Ogtrop; R. W. Vervoort; G. Z. Heller; D. M. Stasinopoulos; R. A. Rigby

2011-01-01

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 statistical model to forecast streamflow up to 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 th...

Long-range forecasting of intermittent streamflow

OpenAIRE

F. F. van Ogtrop; R. W. Vervoort; G. Z. Heller; D. M. Stasinopoulos; R. A. Rigby

2011-01-01

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 probabil...

Methane bursts as a trigger for intermittent lake-forming climates on post-Noachian Mars

Science.gov (United States)

Kite, Edwin S.; Gao, Peter; Goldblatt, Colin; Mischna, Michael A.; Mayer, David P.; Yung, Yuk L.

2017-10-01

Lakes existed on Mars later than 3.6 billion years ago, according to sedimentary evidence for deltaic deposition. The observed fluviolacustrine deposits suggest that individual lake-forming climates persisted for at least several thousand years (assuming dilute flow). But the lake watersheds’ little-weathered soils indicate a largely dry climate history, with intermittent runoff events. Here we show that these observational constraints, although inconsistent with many previously proposed triggers for lake-forming climates, are consistent with a methane burst scenario. In this scenario, chaotic transitions in mean obliquity drive latitudinal shifts in temperature and ice loading that destabilize methane clathrate. Using numerical simulations, we find that outgassed methane can build up to atmospheric levels sufficient for lake-forming climates, if methane clathrate initially occupies more than 4% of the total volume in which it is thermodynamically stable. Such occupancy fractions are consistent with methane production by water-rock reactions due to hydrothermal circulation on early Mars. We further estimate that photochemical destruction of atmospheric methane curtails the duration of individual lake-forming climates to less than a million years, consistent with observations. We conclude that methane bursts represent a potential pathway for intermittent excursions to a warm, wet climate state on early Mars.

A theoretically consistent stochastic cascade for temporal disaggregation of intermittent rainfall

Science.gov (United States)

Lombardo, F.; Volpi, E.; Koutsoyiannis, D.; Serinaldi, F.

2017-06-01

Generating fine-scale time series of intermittent rainfall that are fully consistent with any given coarse-scale totals is a key and open issue in many hydrological problems. We propose a stationary disaggregation method that simulates rainfall time series with given dependence structure, wet/dry probability, and marginal distribution at a target finer (lower-level) time scale, preserving full consistency with variables at a parent coarser (higher-level) time scale. We account for the intermittent character of rainfall at fine time scales by merging a discrete stochastic representation of intermittency and a continuous one of rainfall depths. This approach yields a unique and parsimonious mathematical framework providing general analytical formulations of mean, variance, and autocorrelation function (ACF) for a mixed-type stochastic process in terms of mean, variance, and ACFs of both continuous and discrete components, respectively. To achieve the full consistency between variables at finer and coarser time scales in terms of marginal distribution and coarse-scale totals, the generated lower-level series are adjusted according to a procedure that does not affect the stochastic structure implied by the original model. To assess model performance, we study rainfall process as intermittent with both independent and dependent occurrences, where dependence is quantified by the probability that two consecutive time intervals are dry. In either case, we provide analytical formulations of main statistics of our mixed-type disaggregation model and show their clear accordance with Monte Carlo simulations. An application to rainfall time series from real world is shown as a proof of concept.

29 CFR 825.205 - Increments of FMLA leave for intermittent or reduced schedule leave.

Science.gov (United States)

2010-07-01

... intermittent leave or working a reduced leave schedule to commence or end work mid-way through a shift, such as... per week, but works only 20 hours a week under a reduced leave schedule, the employee's ten hours of... 29 Labor 3 2010-07-01 2010-07-01 false Increments of FMLA leave for intermittent or reduced...

Acute interstitial nephritis induced by intermittent use of Rifampicin in patient with Brucellosis

International Nuclear Information System (INIS)

Salih, S. Bin; Kharal, M.; Qahtani, M.; Dahneem, L.; Nohair, S.

2008-01-01

Acute oliguric renal failure (ARF) developed in a patient 2 days after she was started on intermittent anti-Brucella therapy including rifampicin. The clinical picture was compatible with acute allergic interstitial nephritis. Renal histology revealed mainly acute tubular necrosis with mild tubulo-intertitial mononuclear cellular infiltrate. Intermittent therapy, as in our patient, has been the major factor in the development of rifampicin induced ARF in cases reviewed in literature. (author)

Observation of intermittent transition by electrode biasing in Heliotron J

International Nuclear Information System (INIS)

Shimizu, Kosuke; Kitajima, Sumio; Okamoto, Atsushi

2015-01-01

We observed intermittent increases in the electrode current in electrode biasing experiments in Heliotron J. In addition, electron density and floating potential showed pulsating behavior associated with the electrode current. The relation between line density and electrode current and that between floating potential and electrode current showed a hysteresis feature in transitions. Then it is evident that the pulsating behavior was the intermittent transition between two distinctive states. We also observed the mode (∼10 kHz) that accompanied the pulsating behavior in the power spectrum density of the floating potential and ion saturation current obtained via fast Fourier transform. The electron density gradient increased, and subsequently the power spectrum density of the fluctuation increased. (author)

Elastically driven intermittent microscopic dynamics in soft solids

Science.gov (United States)

Bouzid, Mehdi; Colombo, Jader; Barbosa, Lucas Vieira; Del Gado, Emanuela

2017-06-01

Soft solids with tunable mechanical response are at the core of new material technologies, but a crucial limit for applications is their progressive aging over time, which dramatically affects their functionalities. The generally accepted paradigm is that such aging is gradual and its origin is in slower than exponential microscopic dynamics, akin to the ones in supercooled liquids or glasses. Nevertheless, time- and space-resolved measurements have provided contrasting evidence: dynamics faster than exponential, intermittency and abrupt structural changes. Here we use 3D computer simulations of a microscopic model to reveal that the timescales governing stress relaxation, respectively, through thermal fluctuations and elastic recovery are key for the aging dynamics. When thermal fluctuations are too weak, stress heterogeneities frozen-in upon solidification can still partially relax through elastically driven fluctuations. Such fluctuations are intermittent, because of strong correlations that persist over the timescale of experiments or simulations, leading to faster than exponential dynamics.

Intermittency and correlations in hadronic $Z^0$ decays

CERN Document Server

Abbiendi, G.; Alexander, G.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Blobel, V.; Bloodworth, I.J.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David 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.Marco; Davis, R.; De Jong, S.; de Roeck, A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Fiedler, F.; Fierro, M.; Fleck, I.; Folman, R.; Frey, A.; Furtjes, 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.; Goldberg, J.; Gorn, W.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hobson, P.R.; Hoch, M.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klier, A.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, J.; Michelini, A.; 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.; Ogren, H.O.; Oreglia, M.J.; Orito, S.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycien, M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schmitt, S.; Schoning, A.; Schroder, Matthias; 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, R.; Soldner-Rembold, S.; Spagnolo, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, 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.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Ueda, I.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wackerle, 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...

Intermittent bursts induced by double tearing mode reconnection

Science.gov (United States)

Wei, Lai; Wang, Zheng-Xiong

2014-06-01

Reversed magnetic shear (RMS) configuration is assumed to be the steady-state operation scenario for the future advanced tokamaks like International Thermonuclear Experimental Reactor. In this work, we numerically discover a phenomenon of violent intermittent bursts induced by self-organized double tearing mode (DTM) reconnection in the RMS configuration during the very long evolution, which may continuously lead to annular sawtooth crashes and thus badly impact the desired steady-state operation of the future advanced RMS tokamaks. The key process of the intermittent bursts in the off-axis region is similar to that of the typical sawtooth relaxation oscillation in the positive magnetic shear configuration. It is interestingly found that in the decay phase of the DTM reconnection, the zonal field significantly counteracts equilibrium field to make the magnetic shear between the two rational surfaces so weak that the residual self-generated vortices of the previous DTM burst are able to trigger a reverse DTM reconnection by curling the field lines.

Intermittent bursts induced by double tearing mode reconnection

International Nuclear Information System (INIS)

Wei, Lai; Wang, Zheng-Xiong

2014-01-01

Reversed magnetic shear (RMS) configuration is assumed to be the steady-state operation scenario for the future advanced tokamaks like International Thermonuclear Experimental Reactor. In this work, we numerically discover a phenomenon of violent intermittent bursts induced by self-organized double tearing mode (DTM) reconnection in the RMS configuration during the very long evolution, which may continuously lead to annular sawtooth crashes and thus badly impact the desired steady-state operation of the future advanced RMS tokamaks. The key process of the intermittent bursts in the off-axis region is similar to that of the typical sawtooth relaxation oscillation in the positive magnetic shear configuration. It is interestingly found that in the decay phase of the DTM reconnection, the zonal field significantly counteracts equilibrium field to make the magnetic shear between the two rational surfaces so weak that the residual self-generated vortices of the previous DTM burst are able to trigger a reverse DTM reconnection by curling the field lines

Intermittent bursts induced by double tearing mode reconnection

Energy Technology Data Exchange (ETDEWEB)

Wei, Lai; Wang, Zheng-Xiong, E-mail: zxwang@dlut.edu.cn [Key Laboratory of Materials Modification by Beams of the Ministry of Education, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

2014-06-15

Reversed magnetic shear (RMS) configuration is assumed to be the steady-state operation scenario for the future advanced tokamaks like International Thermonuclear Experimental Reactor. In this work, we numerically discover a phenomenon of violent intermittent bursts induced by self-organized double tearing mode (DTM) reconnection in the RMS configuration during the very long evolution, which may continuously lead to annular sawtooth crashes and thus badly impact the desired steady-state operation of the future advanced RMS tokamaks. The key process of the intermittent bursts in the off-axis region is similar to that of the typical sawtooth relaxation oscillation in the positive magnetic shear configuration. It is interestingly found that in the decay phase of the DTM reconnection, the zonal field significantly counteracts equilibrium field to make the magnetic shear between the two rational surfaces so weak that the residual self-generated vortices of the previous DTM burst are able to trigger a reverse DTM reconnection by curling the field lines.

Low nitrous oxide production in intermittent-feed high performance nitritating reactors

DEFF Research Database (Denmark)

Su, Qingxian; Jensen, Malene M.; Smets, Barth F.

Nitrous oxide (N2O) production from autotrophic nitrogen removal processes, especially nitritating systems, is of growing concern. N2O dynamics were characterized and N2O production factors were quantified in two lab-scale intermittent-feed nitritating SBRs. 93 ± 14% of the oxidized ammonium...... was converted to nitrite, with the average total net N2O production of 2.1 ± 0.7% of the ammonium oxidized. Operation with intermittent feeding appears an effective optimization approach to mitigate N2O emissions from nitritating systems. Net N2O production rates transiently increased with a rise in pH after...

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...

Stochastic index model for intermittent regimes: from preliminary analysis to regionalisation

Directory of Open Access Journals (Sweden)

M. Rianna

2011-04-01

Full Text Available In small and medium-sized basins or in rivers characterized by intermittent discharges, with low or negligible/null observed values for long periods of the year, the correct representation of the discharge regime is important for issues related to water management and to define the amount and quality of water available for irrigation, domestic and recreational uses. In these cases, only one index as a statistical metric is often not enough; it is thus necessary to introduce Flow Duration Curves (FDC.

The aim of this study is therefore to combine a stochastic index flow model capable of reproducing the FDC record period of a river, regardless of the persistence and seasonality of the series, with the theory of total probability in order to calculate how often a river is dry.

The paper draws from preliminary analyses, including a study to estimate the correlation between discharge indicators Q₉₅, Q₅₀ and Q₁ (discharges exceeding 95%, 50% or 1% of the time, respectively and some fundamental characteristics of the basin, as well as to identify homogeneous regions in the target area through the study of several geo-morphological features and climatic conditions. The stochastic model was then applied in one of the homogeneous regions that includes intermittent rivers.

Finally, the model was regionalized by means of regression analysis in order to calculate the FDC for ungauged basins; the reliability of this method was tested using jack-knife validation.

Sensitivity of intermittent streams to climate variations in the USA

Science.gov (United States)

Eng, Kenny; Wolock, David M.; Dettinger, Mike

2015-01-01

There is a great deal of interest in the literature on streamflow changes caused by climate change because of the potential negative effects on aquatic biota and water supplies. Most previous studies have primarily focused on perennial streams, and there have been only a few studies examining the effect of climate variability on intermittent streams. Our objectives in this study were to (1) identify regions of similar zero-flow behavior, and (2) evaluate the sensitivity of intermittent streams to historical variability in climate in the United States. This study was carried out at 265 intermittent streams by evaluating: (1) correlations among time series of flow metrics (number of zero-flow events, the average of the central 50% and largest 10% of flows) with climate (magnitudes, durations and intensity), and (2) decadal changes in the seasonality and long-term trends of these flow metrics. Results identified five distinct seasonality patterns in the zero-flow events. In addition, strong associations between the low-flow metrics and historical changes in climate were found. The decadal analysis suggested no significant seasonal shifts or decade-to-decade trends in the low-flow metrics. The lack of trends or changes in seasonality is likely due to unchanged long-term patterns in precipitation over the time period examined.

Nitrogen removal in the bioreactor landfill system with intermittent aeration at the top of landfilled waste

International Nuclear Information System (INIS)

He Ruo; Shen Dongsheng

2006-01-01

High ammonia concentration of recycled landfill leachate makes it very difficult to treat. In this work, a vertical aerobic/anoxic/anaerobic lab-scale bioreactor landfill system, which was constructed by intermittent aeration at the top of landfilled waste, as a bioreactor for in situ nitrogen removal was investigated during waste stabilization. Intermittent aeration at the top of landfilled waste might stimulate the growth of nitrifying bacteria and denitrifying bacteria in the top and middle layers of waste. The nitrifying bacteria population for the landfill bioreactor with intermittent aeration system reached between10 6 and 10 8 cells/dry g waste, although it decreased 2 orders of magnitude on day 30, due to the inhibitory effect of the acid environment and high organic matter in the landfilled waste. The denitrifying bacteria population increased by between 4 and 13 orders of magnitude compared with conventional anaerobic landfilled waste layers. Leachate NO 3 - -N concentration was very low in both two experimental landfill reactors. After 105 days operation, leachate NH 4 + -N and TN concentrations for the landfill reactor with intermittent aeration system dropped to 186 and 289 mg/l, respectively, while they were still kept above 1000 mg/l for the landfill reactor without intermittent aerobic system. In addition, there is an increase in the rate of waste stabilization as well as an increase of 12% in the total waste settlement for the landfill reactor with intermittent aeration system

Effect of ovariectomy on inflammation induced by intermittent hypoxia in a mouse model of sleep apnea.

Science.gov (United States)

Torres, Marta; Palomer, Xavier; Montserrat, Josep M; Vázquez-Carrera, Manel; Farré, Ramon

2014-10-01

Patient data report marked gender and pre-vs-postmenopausal differences in obstructive sleep apnea (OSA). However, no experimental data are available on how sexual hormones modulate OSA consequences. Here we report novel results on estrogen-modulated heart and brain inflammation in female mice subjected to intermittent hypoxia, a major injurious challenge in OSA. C57BL/6J (14-week old) intact and ovariectomized mice (n=6 each) were subjected to intermittent hypoxia (20 s at 5% and 40s at 21%, 60 cycles/h; 6 h/day). Identical intact and ovariectomized groups breathing room air were controls. After 30 days, the gene expressions of interleukins 6 and 8 (IL-6, IL-8) in the brain and heart tissues were measured. Whereas, compared with normoxia, intermittent hypoxia considerably increased IL-6 and IL-8 gene expressions in intact females, no change was found in ovariectomized mice when comparing normoxia and intermittent hypoxia. These data suggest that estrogens modulate the inflammatory effects of intermittent hypoxia and point to further studies on the role played by sex hormones in OSA. Copyright © 2014 Elsevier B.V. All rights reserved.

High rates of organic carbon processing in the hyporheic zone of intermittent streams.

Science.gov (United States)

Burrows, Ryan M; Rutlidge, Helen; Bond, Nick R; Eberhard, Stefan M; Auhl, Alexandra; Andersen, Martin S; Valdez, Dominic G; Kennard, Mark J

2017-10-16

Organic carbon cycling is a fundamental process that underpins energy transfer through the biosphere. However, little is known about the rates of particulate organic carbon processing in the hyporheic zone of intermittent streams, which is often the only wetted environment remaining when surface flows cease. We used leaf litter and cotton decomposition assays, as well as rates of microbial respiration, to quantify rates of organic carbon processing in surface and hyporheic environments of intermittent and perennial streams under a range of substrate saturation conditions. Leaf litter processing was 48% greater, and cotton processing 124% greater, in the hyporheic zone compared to surface environments when calculated over multiple substrate saturation conditions. Processing was also greater in more saturated surface environments (i.e. pools). Further, rates of microbial respiration on incubated substrates in the hyporheic zone were similar to, or greater than, rates in surface environments. Our results highlight that intermittent streams are important locations for particulate organic carbon processing and that the hyporheic zone sustains this fundamental process even without surface flow. Not accounting for carbon processing in the hyporheic zone of intermittent streams may lead to an underestimation of its local ecological significance and collective contribution to landscape carbon processes.

Therapeutic Efficacy of Intermittent Cryotherapy in the Management ...

African Journals Online (AJOL)

This study was therefore, designed to investigate the efficacy of intermittent cryotherapy in the management of pain among human subjects who sustained closed soft tissue injuries (CSTIs). Subjects' pre- and post-treatment pain perception scores (PPS) using visual analogue scale (VAS) and the sessions of treatment were ...

Clan structure as a source of intermittency in high energy multihadron production

International Nuclear Information System (INIS)

Hove, L. van

1989-01-01

Recently the systematic study of charged hadron multiplicity distributions in high energy hadronic and leptonic collisions has revealed the general occurrence of negative binomial regularities in symmetric CM rapidity windows and of intermittency in very small windows in the central region. The negative binomial regularities imply a particular form of clustering called clan structure, which embodies all Mueller multiparticle correlations. We show that this clan structure leads to intermittency when the simplest assumptions are made on the behaviour of the clans in very small windows. (orig.)

Intermittent Nitrate Use and Risk of Hip Fracture

Science.gov (United States)

Misra, Devyani; Peloquin, Christine; Kiel, Douglas P.; Neogi, Tuhina; Lu, Na; Zhang, Yuqing

2016-01-01

Purpose Nitrates, commonly used anti-anginal medications, also have beneficial effect on bone remodeling and bone density, particularly with intermittent use. However, their effect on fracture risk is not clear. We examined the relation of short-acting nitrate use (proxy for intermittent use) to the risk of hip fracture in a large cohort of older adults with ischemic heart disease. Materials and Methods Participants ≥ 60 years old with ischemic heart disease and without history of hip fracture from The Health Improvement Network (THIN), an electronic medical records database in the UK, were included. The association of incident (new) use of short-acting nitrate formulations (nitroglycerin sublingual/spray/ointment or ISDN injection/sprays) with incident (new-onset) hip fracture risk was examined by plotting Kaplan-Maier curves and calculating Hazard ratios (HR) using Cox proportional hazards regression models. Competing risk by death was analyzed in separate analyses. Results Among 14, 451 pairs of matched nitrate users and non-users (mean age 72±7.6, 41% women for each cohort), 573 fractures occurred during follow up (257 nitrate users; 316 non-users). Hip fracture risk was 33% lower among short-acting nitrate users compared with non-users (HR=0.67, 95% CI 0.53–0.85, p=0.0008). Competing risk analysis by death did not change effect estimates. Conclusion In this large population-based cohort of older adults with ischemic heart disease, we found significant reduction in hip fracture risk with use of short-acting nitrates (intermittent use). Future studies are warranted given the potential for nitrates to be potent, inexpensive and readily available anti-osteoporotic agents. PMID:27720852

Noise-sustained structure, Intermittency, and the Ginzburg--Landau equation

International Nuclear Information System (INIS)

Deissler, R.J.

1985-01-01

The time-dependent generalized Ginzburg--Landau equation is an equation that is related to many physical systems. Solutions of this equation in the presence of low-level external noise are studied. Numerical solutions of this equation in the stationary frame of refernce and with nonzero group velocity that is greater than a critical velocity exhibit a selective spatial amplification of noise resulting in spatially growing waves. These waves in turn result in the formation of a dynamic structure. It is found that the microscopic noise plays an importuant role in the macroscopic dynamics of the system. For certain parameter values the system exhibits intermittent turbulent behavior in which the random nature of the external noise plays a crucial role. A mechanism which may be responsible for the intermittent turbulence occurring in some fluid systems is suggested

A novel inclusion of intermittent generation resources in long term energy auctions

International Nuclear Information System (INIS)

Marambio, Rodrigo; Rudnick, Hugh

2017-01-01

Long term energy auctions are positioning as a valuable tool in order to attract new investments into power systems, especially in Latin American countries where emergent economies characteristics and their correspondent risks are usually present. Even though the focus of these auctions is the long term, there are short term issues involved which actual auction designs fail to include, resulting in an energy allocation that is not necessarily optimal for the system, a condition which becomes more evident in the presence of intermittent renewable technologies. A novel mechanism is formulated to obtain the optimal allocation in long term energy auctions, considering short term generation profiles from both intermittent and conventional base load technologies, and also their risk aversions. The proposed mechanism is developed and simulations are made for some scenarios in the Chilean power market, with different levels of renewable penetration. Significant cost savings are achieved for the final consumers in relation to energy purchases, in comparison with a mechanism that follows the demand profile. As more renewable intermittent capacity enters the power system it is evident the need for changes in the energy auctions allocation mechanisms, including elements to exploit the synergies among participants in the short term. - Highlights: • Risk management consideration in technology neutral auctions allocation. • Allocation mechanism in technology neutral auctions with intermittent technologies. • Renewable and conventional technologies energy auction offer curves. • Increase bid prices in auctions as a consequence of solar technology support.

Chaos as an intermittently forced linear system.

Science.gov (United States)

Brunton, Steven L; Brunton, Bingni W; Proctor, Joshua L; Kaiser, Eurika; Kutz, J Nathan

2017-05-30

Understanding the interplay of order and disorder in chaos is a central challenge in modern quantitative science. Approximate linear representations of nonlinear dynamics have long been sought, driving considerable interest in Koopman theory. We present a universal, data-driven decomposition of chaos as an intermittently forced linear system. This work combines delay embedding and Koopman theory to decompose chaotic dynamics into a linear model in the leading delay coordinates with forcing by low-energy delay coordinates; this is called the Hankel alternative view of Koopman (HAVOK) analysis. This analysis is applied to the Lorenz system and real-world examples including Earth's magnetic field reversal and measles outbreaks. In each case, forcing statistics are non-Gaussian, with long tails corresponding to rare intermittent forcing that precedes switching and bursting phenomena. The forcing activity demarcates coherent phase space regions where the dynamics are approximately linear from those that are strongly nonlinear.The huge amount of data generated in fields like neuroscience or finance calls for effective strategies that mine data to reveal underlying dynamics. Here Brunton et al.develop a data-driven technique to analyze chaotic systems and predict their dynamics in terms of a forced linear model.

Subintimal angioplasty in femoropopliteal region-Mid-term results

International Nuclear Information System (INIS)

Koecher, Martin; Cerna, Marie; Utikal, Petr; Kozak, Jiri; Sisola, Ivan; Thomas, Rohit P.; Bachleda, Petr; Drac, Petr; Sekanina, Zdenek; Langova, Katerina

2010-01-01

Purpose: Subintimal angioplasty is becoming more frequently used treatment option for patients with long arterial occlusions or diffuse atherosclerotic changes as an alternative to surgical treatment in claudicants especially in patients with critical limb ischemia. The aim of our article is to retrospectively assess mid-term outcomes of subintimal angioplasty of chronic arterial occlusions in femoropopliteal region followed clinically and by Doppler ultrasonography. Materials and methods: From May 2002 to December 2007, 133 femoropopliteal artery occlusions in 123 patients were indicated for subintimal recanalisation. The indications for treatment were intermittent claudications in 84 patients (63.15%) and critical limb ischemia in 49 patients (36.85%). The median length of lesions was 11.4 cm, range 2-30 cm. Except doppler ultrasonographic examination done 24 h after the procedure and clinical examination before discharge, both clinical and ultrasonographic examinations were performed 6 and 12 months after the procedure and yearly thereafter. Statistical analysis of our cohort was performed by Kaplan-Meier analysis, log-rank test and Cox regression. Results: Technical success was achieved in 86.46%. Primary patency rate was 83.1% (SE: 3.9%), 67.5% (SE: 5%), 58% (SE: 5.9%) a 48.4% (SE: 7.1%) at 6, 12, 24 and 36 months respectively. No statistically significant difference of primary patency was found between the group of claudicants and the group of patient with critical limb ischemia. Statistically significant prediction factors for primary patency were only the quality of the run off and the length of the occlusion. Limb salvage rate in our group of patients with critical limb ischemia was 80.8% at 12 months. Conclusion: Subintimal recanalisation is a simple and safe procedure for treatment of chronic peripheral arterial occlusions with high primary technical success rate, acceptable primary patency rate, low percentage of complications and mortality is as low as

Intermittency in super-high energy cosmic ray events

International Nuclear Information System (INIS)

Gladysz-Dziadus, E.

1988-12-01