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Sample records for activity msna microneurography

  1. Effects of graded LBNP on MSNA and interstitial norepinephrine

    NASA Technical Reports Server (NTRS)

    Khan, Mazhar H.; Sinoway, Lawrence I.; MacLean, David A.

    2002-01-01

    Exposure to lower body negative pressure (LBNP) leads to an increased activation of the sympathetic nervous system (SNS) and an increase in muscle sympathetic nerve activity (MSNA). In this study, we examined the relationship between MSNA and interstitial norepinephrine (NE(i)) concentrations during LBNP. Twelve healthy volunteers were studied (26 +/- 6 yr). Simultaneous MSNA and microdialysis data were collected in six of these subjects. Measurements of MSNA (microneurography) and NE(i) (microdialysis, vastus lateralis) were performed at rest and then during an incremental LBNP paradigm (-10, -30, and -50 mmHg). MSNA rose as a function of LBNP (P < 0.001, n = 12). The plasma norepinephrine (NE(p)) concentration was 0.9 +/- 0.1 nmol/l at rest (n = 12). NE(i) measured in six subjects rose from 5.2 +/- 0.8 nmol/l at rest to 17.0 +/- 1.7 nmol/l at -50 mmHg (P < 0.001). Of note, the rise in NE(p) with LBNP was considerably less compared with the changes in NE(i) (Delta21 +/- 6% vs. Delta197 +/- 52%, n = 6, P < 0.015). MSNA and NE(i) showed a significant linear relationship (r = 0.721, P < 0.004). Activation of the SNS increased MSNA and NE(i) levels. The magnitude of the NE(i) increase was far greater than that seen for NE(p) suggesting that NE movement into the circulation decreases with baroreceptor unloading.

  2. Muscle sympathetic nerve activity in blood pressure control against gravitational stress.

    PubMed

    Mano, T

    2001-10-01

    Muscle sympathetic nerve activity (MSNA) can be directly recorded from human peripheral nerves in situ using microneurography. MSNA plays an essential role to control systemic blood pressure against gravitational stress. MSNA was enhanced by changing posture against terrestrial gravity from lying to sitting, and from sitting to standing. This activity was enhanced by head-up tilt depending on the gravitational input from the head to the leg (+Gz) in the human body. Orthostatic hypotension occurred when MSNA response to gravitational stress was impaired both in high and low responders of this sympathetic outflow. Syncope was preceded and/or associated by a withdrawal of MSNA. MSNA was suppressed by short-term exposure to microgravity but was enhanced after long-term exposure to microgravity. Orthostatic intolerance after exposure to prolonged microgravity was associated with a reduction of increased MSNA response to gravitational stress. Aging influenced gravity-related responses of MSNA.

  3. Contributions of MSNA and stroke volume to orthostatic intolerance following bed rest

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

    We examined whether the altered orthostatic tolerance following 14 days of head-down tilt bed rest (HDBR) was related to inadequate sympathetic outflow or to excessive reductions in cardiac output during a 10- to 15-min head-up tilt (HUT) test. Heart rate, blood pressure (BP, Finapres), muscle sympathetic nerve activity (MSNA, microneurography), and stroke volume blood velocity (SVV, Doppler ultrasound) were assessed during supine 30 degrees (5 min) and 60 degrees (5-10 min) HUT positions in 15 individuals who successfully completed the pre-HDBR test without evidence of orthostatic intolerance. Subjects were classified as being orthostatically tolerant (OT, n = 9) or intolerant (OI, n = 6) following the post-HDBR test. MSNA, BP, and SVV during supine and HUT postures were not altered in the OT group. Hypotension during 60 degrees HUT in the post-bed rest test for the OI group (P < 0.05) was associated with a blunted increase in MSNA (P < 0.05). SVV was reduced following HDBR in the OI group (main effect of HDBR, P < 0.02). The data support the hypothesis that bed rest-induced orthostatic intolerance is related to an inadequate increase in sympathetic discharge that cannot compensate for a greater postural reduction in stroke volume.

  4. Microneurography as a tool in clinical neurophysiology to investigate peripheral neural traffic in humans.

    PubMed

    Mano, Tadaaki; Iwase, Satoshi; Toma, Shinobu

    2006-11-01

    Microneurography is a method using metal microelectrodes to investigate directly identified neural traffic in myelinated as well as unmyelinated efferent and afferent nerves leading to and coming from muscle and skin in human peripheral nerves in situ. The present paper reviews how this technique has been used in clinical neurophysiology to elucidate the neural mechanisms of autonomic regulation, motor control and sensory functions in humans under physiological and pathological conditions. Microneurography is particularly important to investigate efferent and afferent neural traffic in unmyelinated C fibers. The recording of efferent discharges in postganglionic sympathetic C efferent fibers innervating muscle and skin (muscle sympathetic nerve activity; MSNA and skin sympathetic nerve activity; SSNA) provides direct information about neural control of autonomic effector organs including blood vessels and sweat glands. Sympathetic microneurography has become a potent tool to reveal neural functions and dysfunctions concerning blood pressure control and thermoregulation. This recording has been used not only in wake conditions but also in sleep to investigate changes in sympathetic neural traffic during sleep and sleep-related events such as sleep apnea. The same recording was also successfully carried out by astronauts during spaceflight. Recordings of afferent discharges from muscle mechanoreceptors have been used to understand the mechanisms of motor control. Muscle spindle afferent information is particularly important for the control of fine precise movements. It may also play important roles to predict behavior outcomes during learning of a motor task. Recordings of discharges in myelinated afferent fibers from skin mechanoreceptors have provided not only objective information about mechanoreceptive cutaneous sensation but also the roles of these signals in fine motor control. Unmyelinated mechanoreceptive afferent discharges from hairy skin seem to be

  5. Effects of 12 Months Continuous Positive Airway Pressure on Sympathetic Activity Related Brainstem Function and Structure in Obstructive Sleep Apnea

    PubMed Central

    Henderson, Luke A.; Fatouleh, Rania H.; Lundblad, Linda C.; McKenzie, David K.; Macefield, Vaughan G.

    2016-01-01

    Muscle sympathetic nerve activity (MSNA) is greatly elevated in patients with obstructive sleep apnea (OSA) during normoxic daytime wakefulness. Increased MSNA is a precursor to hypertension and elevated cardiovascular morbidity and mortality. However, the mechanisms underlying the high MSNA in OSA are not well understood. In this study we used concurrent microneurography and magnetic resonance imaging to explore MSNA-related brainstem activity changes and anatomical changes in 15 control and 15 OSA subjects before and after 6 and 12 months of continuous positive airway pressure (CPAP) treatment. We found that following 6 and 12 months of CPAP treatment, resting MSNA levels were significantly reduced in individuals with OSA. Furthermore, this MSNA reduction was associated with restoration of MSNA-related brainstem activity and structural changes in the medullary raphe, rostral ventrolateral medulla, dorsolateral pons, and ventral midbrain. This restoration occurred after 6 months of CPAP treatment and was maintained following 12 months CPAP. These findings show that continual CPAP treatment is an effective long-term treatment for elevated MSNA likely due to its effects on restoring brainstem structure and function. PMID:27013952

  6. Contributions of Central Command and Muscle Feedback to Sympathetic Nerve Activity in Contracting Human Skeletal Muscle

    PubMed Central

    Boulton, Daniel; Taylor, Chloe E.; Macefield, Vaughan G.; Green, Simon

    2016-01-01

    During voluntary contractions, muscle sympathetic nerve activity (MSNA) to contracting muscles increases in proportion to force but the underlying mechanisms are not clear. To shed light on these mechanisms, particularly the influences of central command and muscle afferent feedback, the present study tested the hypothesis that MSNA is greater during voluntary compared with electrically-evoked contractions. Seven male subjects performed a series of 1-min isometric dorsiflexion contractions (left leg) separated by 2-min rest periods, alternating between voluntary and electrically-evoked contractions at similar forces (5–10% of maximum). MSNA was recorded continuously (microneurography) from the left peroneal nerve and quantified from cardiac-synchronized, negative-going spikes in the neurogram. Compared with pre-contraction values, MSNA increased by 51 ± 34% (P < 0.01) during voluntary contractions but did not change significantly during electrically-evoked contractions (−8 ± 12%, P > 0.05). MSNA analyzed at 15-s intervals revealed that this effect of voluntary contraction appeared 15–30 s after contraction onset (P < 0.01), remained elevated until the end of contraction, and disappeared within 15 s after contraction. These findings suggest that central command, and not feedback from contracting muscle, is the primary mechanism responsible for the increase in MSNA to contracting muscle. The time-course of MSNA suggests that there is a longer delay in the onset of this effect compared with its cessation after contraction. PMID:27242537

  7. Dissociation of muscle sympathetic nerve activity and leg vascular resistance in humans

    NASA Technical Reports Server (NTRS)

    Shoemaker, J. K.; Herr, M. D.; Sinoway, L. I.

    2000-01-01

    We examined the hypothesis that the increase in inactive leg vascular resistance during forearm metaboreflex activation is dissociated from muscle sympathetic nerve activity (MSNA). MSNA (microneurography), femoral artery mean blood velocity (FAMBV, Doppler), mean arterial pressure (MAP), and heart rate (HR) were assessed during fatiguing static handgrip exercise (SHG, 2 min) followed by posthandgrip ischemia (PHI, 2 min). Whereas both MAP and MSNA increase during SHG, the transition from SHG to PHI is characterized by a transient reduction in MAP but sustained elevation in MSNA, facilitating separation of these factors in vivo. Femoral artery vascular resistance (FAVR) was calculated (MAP/MBV). MSNA increased by 59 +/- 20% above baseline during SHG (P < 0.05) and was 58 +/- 18 and 78 +/- 18% above baseline at 10 and 20 s of PHI, respectively (P < 0.05 vs. baseline). Compared with baseline, FAVR increased 51 +/- 22% during SHG (P < 0.0001) but returned to baseline levels during the first 30 s of PHI, reflecting the changes in MAP (P < 0.005) and not MSNA. It was concluded that control of leg muscle vascular resistance is sensitive to changes in arterial pressure and can be dissociated from sympathetic factors.

  8. [Microneurography--from basic aspects to clinical applications and application in space medicine].

    PubMed

    Mano, Tadaaki

    2009-03-01

    Microneurography is an electrophysiological method that directly records impulse traffic from human peripheral nerves by using metal microelectrodes. This method enables the recording of identified postganglionic sympathetic efferent neural traffic leading to the skeletal muscles (muscle sympathetic nerve activity) and skin (skin sympathetic nerve activity), as well as myelinated and unmyelinated afferent nerve impulses from the sensory receptors in skeletal muscles (muscle spindles, Golgi tendon organs, and nociceptors) and skin (skin mechanoreceptors and noci-thermoceptors). The clinical applications of sympathetic microneurography are useful for the elucidation of the neural mechanisms of abnormal blood pressure control and thermoregulation. Sympathetic microneurography is also used in space medicine to elucidate changes in sympathetic neural traffic during and after exposure to simulated microgravity and spaceflight. The clinical applications of sensory microneurography are useful to clarify the neural mechanisms underlying abnormalities in muscle and skin sensation and those in sensory motor control. Microstimulation by using the microneurography technique can also be used to determine the peripheral sensory, sympathetic, and motor nerve functions.

  9. Limb venous distension evokes sympathetic activation via stimulation of the limb afferents in humans.

    PubMed

    Cui, Jian; McQuillan, Patrick M; Blaha, Cheryl; Kunselman, Allen R; Sinoway, Lawrence I

    2012-08-15

    We have recently shown that a saline infusion in the veins of an arterially occluded human forearm evokes a systemic response with increases in muscle sympathetic nerve activity (MSNA) and blood pressure. In this report, we examined whether this response was a reflex that was due to venous distension. Blood pressure (Finometer), heart rate, and MSNA (microneurography) were assessed in 14 young healthy subjects. In the saline trial (n = 14), 5% forearm volume normal saline was infused in an arterially occluded arm. To block afferents in the limb, 90 mg of lidocaine were added to the same volume of saline in six subjects during a separate visit. To examine whether interstitial perfusion of normal saline alone induced the responses, the same volume of albumin solution (5% concentration) was infused in 11 subjects in separate studies. Lidocaine abolished the MSNA and blood pressure responses seen with saline infusion. Moreover, compared with the saline infusion, an albumin infusion induced a larger (MSNA: Δ14.3 ± 2.7 vs. Δ8.5 ± 1.3 bursts/min, P < 0.01) and more sustained MSNA and blood pressure responses. These data suggest that venous distension activates afferent nerves and evokes a powerful systemic sympathoexcitatory reflex. We posit that the venous distension plays an important role in evoking the autonomic adjustments seen with postural stress in human subjects.

  10. Carotid baroreflex regulation of sympathetic nerve activity during dynamic exercise in humans

    NASA Technical Reports Server (NTRS)

    Fadel, P. J.; Ogoh, S.; Watenpaugh, D. E.; Wasmund, W.; Olivencia-Yurvati, A.; Smith, M. L.; Raven, P. B.

    2001-01-01

    We sought to determine whether carotid baroreflex (CBR) control of muscle sympathetic nerve activity (MSNA) was altered during dynamic exercise. In five men and three women, 23.8 +/- 0.7 (SE) yr of age, CBR function was evaluated at rest and during 20 min of arm cycling at 50% peak O(2) uptake using 5-s periods of neck pressure and neck suction. From rest to steady-state arm cycling, mean arterial pressure (MAP) was significantly increased from 90.0 +/- 2.7 to 118.7 +/- 3.6 mmHg and MSNA burst frequency (microneurography at the peroneal nerve) was elevated by 51 +/- 14% (P < 0.01). However, despite the marked increases in MAP and MSNA during exercise, CBR-Delta%MSNA responses elicited by the application of various levels of neck pressure and neck suction ranging from +45 to -80 Torr were not significantly different from those at rest. Furthermore, estimated baroreflex sensitivity for the control of MSNA at rest was the same as during exercise (P = 0.74) across the range of neck chamber pressures. Thus CBR control of sympathetic nerve activity appears to be preserved during moderate-intensity dynamic exercise.

  11. Strength training reduces arterial blood pressure but not sympathetic neural activity in young normotensive subjects

    NASA Technical Reports Server (NTRS)

    Carter, Jason R.; Ray, Chester A.; Downs, Emily M.; Cooke, William H.

    2003-01-01

    The effects of resistance training on arterial blood pressure and muscle sympathetic nerve activity (MSNA) at rest have not been established. Although endurance training is commonly recommended to lower arterial blood pressure, it is not known whether similar adaptations occur with resistance training. Therefore, we tested the hypothesis that whole body resistance training reduces arterial blood pressure at rest, with concomitant reductions in MSNA. Twelve young [21 +/- 0.3 (SE) yr] subjects underwent a program of whole body resistance training 3 days/wk for 8 wk. Resting arterial blood pressure (n = 12; automated sphygmomanometer) and MSNA (n = 8; peroneal nerve microneurography) were measured during a 5-min period of supine rest before and after exercise training. Thirteen additional young (21 +/- 0.8 yr) subjects served as controls. Resistance training significantly increased one-repetition maximum values in all trained muscle groups (P < 0.001), and it significantly decreased systolic (130 +/- 3 to 121 +/- 2 mmHg; P = 0.01), diastolic (69 +/- 3 to 61 +/- 2 mmHg; P = 0.04), and mean (89 +/- 2 to 81 +/- 2 mmHg; P = 0.01) arterial blood pressures at rest. Resistance training did not affect MSNA or heart rate. Arterial blood pressures and MSNA were unchanged, but heart rate increased after 8 wk of relative inactivity for subjects in the control group (61 +/- 2 to 67 +/- 3 beats/min; P = 0.01). These results indicate that whole body resistance exercise training might decrease the risk for development of cardiovascular disease by lowering arterial blood pressure but that reductions of pressure are not coupled to resistance exercise-induced decreases of sympathetic tone.

  12. Interstitial pH, K(+), lactate, and phosphate determined with MSNA during exercise in humans

    NASA Technical Reports Server (NTRS)

    MacLean, D. A.; Imadojemu, V. A.; Sinoway, L. I.

    2000-01-01

    The purpose of the present study was to use the microdialysis technique to simultaneously measure the interstitial concentrations of several putative stimulators of the exercise pressor reflex during 5 min of intermittent static quadriceps exercise in humans (n = 7). Exercise resulted in approximately a threefold (P < 0.05) increase in muscle sympathetic nerve activity (MSNA) and 13 +/- 3 beats/min (P < 0.05) and 20 +/- 2 mmHg (P < 0.05) increases in heart rate and blood pressure, respectively. During recovery, all reflex responses quickly returned to baseline. Interstitial lactate levels were increased (P < 0.05) from rest (1.1 +/- 0.1 mM) to exercise (1. 6 +/- 0.2 mM) and were further increased (P < 0.05) during recovery (2.0 +/- 0.2 mM). Dialysate phosphate concentrations were 0.55 +/- 0. 04, 0.71 +/- 0.05, and 0.48 +/- 0.03 mM during rest, exercise, and recovery, respectively, and were significantly elevated during exercise. At the onset of exercise, dialysate K(+) levels rose rapidly above resting values (4.2 +/- 0.1 meq/l) and continued to increase during the exercise bout. After 5 min of contractions, dialysate K(+) levels had peaked with an increase (P < 0.05) of 0.6 +/- 0.1 meq/l and subsequently decreased during recovery, not being different from rest after 3 min. In contrast, H(+) concentrations rapidly decreased (P < 0.05) from resting levels (69.4 +/- 3.7 nM) during quadriceps exercise and continued to decrease with a mean decline (P < 0.05) of 16.7 +/- 3.8 nM being achieved after 5 min. During recovery, H(+) concentrations rapidly increased and were not significantly different from baseline after 1 min. This study represents the first time that skeletal muscle interstitial pH, K(+), lactate, and phosphate have been measured in conjunction with MSNA, heart rate, and blood pressure during intermittent static quadriceps exercise in humans. These data suggest that interstitial K(+) and phosphate, but not lactate and H(+), may contribute to the stimulation

  13. Role of adenosine in the sympathetic activation produced by isometric exercise in humans.

    PubMed Central

    Costa, F; Biaggioni, I

    1994-01-01

    Isometric exercise increases sympathetic nerve activity and blood pressure. This exercise pressor reflex is partly mediated by metabolic products activating muscle afferents (metaboreceptors). Whereas adenosine is a known inhibitory neuromodulator, there is increasing evidence that it activates afferent nerves. We, therefore, examined the hypothesis that adenosine stimulates muscle afferents and participates in the exercise pressor reflex in healthy volunteers. Intraarterial administration of adenosine into the forearm, during venous occlusion to prevent systemic effects, mimicked the response to exercise, increasing muscle sympathetic nerve activity (MSNA, lower limb microneurography) and mean arterial blood pressure (MABP) at all doses studied (2, 3, and 4 mg). Heart rate increased only with the highest dose. Intrabrachial adenosine (4 mg) increased MSNA by 96 +/- 25% (n = 6, P < 0.01) and MABP by 12 +/- 3 mmHg (P < 0.01). Adenosine produced forearm discomfort, but equivalent painful stimuli (forearm ischemia and cold exposure) increased MSNA significantly less than adenosine. Furthermore, adenosine receptor antagonism with intrabrachial theophylline (1 microgram/ml forearm per min) blocked the increase in MSNA (92 +/- 15% vs. 28 +/- 6%, n = 7, P < 0.01) and MABP (38 +/- 6 vs. 27 +/- 4 mmHg, P = 0.01) produced by isometric handgrip (30% of maximal voluntary contraction) in the infused arm, but not the contralateral arm. Theophylline did not prevent the increase in heart rate produced by handgrip, a response mediated more by central command than muscle afferent activation. We propose that endogenous adenosine contributes to the activation of muscle afferents involved in the exercise pressor reflex in humans. PMID:8163667

  14. Increased Muscle Sympathetic Nerve Activity and Impaired Executive Performance Capacity in Obstructive Sleep Apnea

    PubMed Central

    Goya, Thiago T.; Silva, Rosyvaldo F.; Guerra, Renan S.; Lima, Marta F.; Barbosa, Eline R.F.; Cunha, Paulo Jannuzzi; Lobo, Denise M.L.; Buchpiguel, Carlos A.; Busatto-Filho, Geraldo; Negrão, Carlos E.; Lorenzi-Filho, Geraldo; Ueno-Pardi, Linda M.

    2016-01-01

    Study Objectives: To investigate muscle sympathetic nerve activity (MSNA) response and executive performance during mental stress in obstructive sleep apnea (OSA). Methods: Individuals with no other comorbidities (age = 52 ± 1 y, body mass index = 29 ± 0.4, kg/m2) were divided into two groups: (1) control (n = 15) and (2) untreated OSA (n = 20) defined by polysomnography. Mini-Mental State of Examination (MMSE) and Inteligence quocient (IQ) were assessed. Heart rate (HR), blood pressure (BP), and MSNA (microneurography) were measured at baseline and during 3 min of the Stroop Color Word Test (SCWT). Sustained attention and inhibitory control were assessed by the number of correct answers and errors during SCWT. Results: Control and OSA groups (apnea-hypopnea index, AHI = 8 ± 1 and 47 ± 1 events/h, respectively) were similar in age, MMSE, and IQ. Baseline HR and BP were similar and increased similarly during SCWT in control and OSA groups. In contrast, baseline MSNA was higher in OSA compared to controls. Moreover, MSNA significantly increased in the third minute of SCWT in OSA, but remained unchanged in controls (P < 0.05). The number of correct answers was lower and the number of errors was significantly higher during the second and third minutes of SCWT in the OSA group (P < 0.05). There was a significant correlation (P < 0.01) between the number of errors in the third minute of SCWT with AHI (r = 0.59), arousal index (r = 0.55), and minimum O2 saturation (r = −0.57). Conclusions: As compared to controls, MSNA is increased in patients with OSA at rest, and further significant MSNA increments and worse executive performance are seen during mental stress. Clinical Trial Registration: URL: http://www.clinicaltrials.gov, registration number: NCT002289625. Citation: Goya TT, Silva RF, Guerra RS, Lima MF, Barbosa ER, Cunha PJ, Lobo DM, Buchpiguel CA, Busatto-Filho G, Negrão CE, Lorenzi-Filho G, Ueno-Pardi LM. Increased muscle sympathetic nerve activity and

  15. Microneurography in relation to intraneural topography: somatotopic organisation of median nerve fascicles in humans.

    PubMed Central

    Hallin, R G

    1990-01-01

    Microneurography was performed in median nerve sensory fascicles with concentric needle electrodes and with conventional tungsten microneedles. The latter electrodes preferentially recorded activity from the myelinated fibres in the whole fascicle. By contrast, due to its special design, a concentric needle can record activity selectively from even a small part of a fascicle. High amplitude signals in C fibres can be discriminated close to Schwann cells that envelope unmyelinated axons. Apart from being biased for activity in thin fibres, the concentric needles can also record signals from nearby myelinated fibres. The palmar receptive fields of such fibre groups were not congruent with the areas traditionally attributed to multiunit skin afferents in humans, namely the innervation zone(s) of one or two adjacent digital nerve(s). Instead, the multiunit fields often comprised small parts of a digital nerve innervation area, frequently only the pulp of a finger. Single units were always localised within previously screened multiunit areas. Contrary to some previously accepted tenets it is probable that single unit activity in myelinated fibres in these studies is recorded extra-axonally near to a node of Ranvier. The findings also suggest the presence of a somatotopy in human limb nerve fascicles, comparable to that previously established in the spinal cord and the somatosensory cortex. Images PMID:2246655

  16. In Vivo MR Microneurography of the Tibial and Common Peroneal Nerves

    PubMed Central

    Felisaz, Paolo F.; Chang, Eric Y.; Montagna, Stefano; Baldi, Maurizia

    2014-01-01

    MR microneurography is a noninvasive technique that provides visualization of the microanatomy of peripheral nerves, otherwise available only with histopathology. The objective of this study was to present a protocol to visualize the microstructure of peripheral nerves in vivo, using a 3T MRI scanner with a clinical set of coils and sequences. The tibial and the common peroneal nerves of healthy volunteers were imaged above the medial malleolus and at the level of the fibular head, respectively. The acquired images provided details about the internal structure of peripheral nerves, with visualization of the fascicles, the interfascicular fat, the epineurium, and the perineurium. MR microneurography can be performed in a clinical setting with acceptable imaging times and can be a potentially powerful tool that complements standard MR neurography. PMID:25548670

  17. In Vivo MR Microneurography of the Tibial and Common Peroneal Nerves.

    PubMed

    Felisaz, Paolo F; Chang, Eric Y; Carne, Irene; Montagna, Stefano; Balducci, Francesco; Maugeri, Giulia; Pichiecchio, Anna; Calliada, Fabrizio; Baldi, Maurizia; Bastianello, Stefano

    2014-01-01

    MR microneurography is a noninvasive technique that provides visualization of the microanatomy of peripheral nerves, otherwise available only with histopathology. The objective of this study was to present a protocol to visualize the microstructure of peripheral nerves in vivo, using a 3T MRI scanner with a clinical set of coils and sequences. The tibial and the common peroneal nerves of healthy volunteers were imaged above the medial malleolus and at the level of the fibular head, respectively. The acquired images provided details about the internal structure of peripheral nerves, with visualization of the fascicles, the interfascicular fat, the epineurium, and the perineurium. MR microneurography can be performed in a clinical setting with acceptable imaging times and can be a potentially powerful tool that complements standard MR neurography.

  18. Role of sympathetic neural activation in age- and habitual exercise-related differences in the thermic effect of food.

    PubMed

    Jones, Pamela Parker; Van Pelt, Rachael E; Johnson, David G; Seals, Douglas R

    2004-10-01

    The thermic effect of food (TEF) declines with advancing age in adult humans but is enhanced in the habitually exercising state. The responsiveness of the sympathetic nervous system (SNS) has been implicated in these differences in TEF. We tested the hypotheses that 1) the reduction in TEF with aging is associated with an attenuated SNS response to acute energy intake; and 2) the greater TEF observed in endurance exercise-trained adults is associated with an augmented SNS response. Four groups of healthy men were studied: 16 young and 11 older sedentary men and nine young and 10 older habitually exercising men. Metabolic rate (indirect calorimetry, ventilated hood), skeletal muscle sympathetic nerve activity (MSNA; peroneal microneurography), and plasma norepinephrine and plasma epinephrine concentrations were measured before and for up to 4 h after ingestion of a carbohydrate drink (2.5 g/kg fat-free mass). TEF was approximately 50% greater in young compared with older men (P < 0.05) and approximately 25% greater in exercising compared with sedentary men (P < 0.05). In contrast, the MSNA, plasma norepinephrine, and plasma epinephrine responses were not different among the four groups. Covarying for MSNA did not significantly alter the observed differences in TEF. Habitual exercise status did not affect the age-associated decline in TEF. These findings demonstrate that altered postprandial whole-body and skeletal muscle SNS activation is not an important mechanism mediating either the reduction in TEF with aging or the augmented TEF associated with the exercise-trained state in healthy men. Differences in beta-adrenergic responsiveness to postprandial sympathoadrenal stimulation and/or nonsympathetic adrenergic influences likely explain the age- and habitual exercise-related differences in TEF.

  19. Generalised anhidrosis: different lesion sites demonstrated by microneurography and skin biopsy.

    PubMed

    Donadio, V; Montagna, P; Nolano, M; Cortelli, P; Misciali, C; Pierangeli, G; Provitera, V; Casano, A; Baruzzi, A; Liguori, R

    2005-04-01

    Generalised anhidrosis (GA) shows a uniform clinical picture whether the pathogenesis involves intrinsic abnormalities of sweat glands or postganglionic sympathetic cholinergic nerve dysfunction. We describe two patients who presented intolerance to heat and anhidrosis. In the first patient, symptoms started at 33 years of age, and were associated with absent tendon reflexes and a mydriatic right pupil unreactive to light. The other patient had been unable to sweat since birth. GA was diagnosed on the basis of clinical findings and thermoregulatory tests. Microneurography and morphological analysis of the skin and its innervation disclosed a different lesion site underlying GA in the two patients, and distinguished between a postganglionic autonomic nerve fibre lesion and sweat gland dysfunction.

  20. Comparable Attenuation of Sympathetic Nervous System Activity in Obese Subjects with Normal Glucose Tolerance, Impaired Glucose Tolerance, and Treatment Naïve Type 2 Diabetes following Equivalent Weight Loss.

    PubMed

    Straznicky, Nora E; Grima, Mariee T; Sari, Carolina I; Lambert, Elisabeth A; Phillips, Sarah E; Eikelis, Nina; Mariani, Justin A; Kobayashi, Daisuke; Hering, Dagmara; Dixon, John B; Lambert, Gavin W

    2016-01-01

    Background and Purpose: Elevated sympathetic nervous system (SNS) activity is a characteristic of obesity and type 2 diabetes (T2D) that contributes to target organ damage and cardiovascular risk. In this study we examined whether baseline metabolic status influences the degree of sympathoinhibition attained following equivalent dietary weight loss. Methods: Un-medicated obese individuals categorized as normal glucose tolerant (NGT, n = 15), impaired glucose tolerant (IGT, n = 24), and newly-diagnosed T2D (n = 15) consumed a hypocaloric diet (29% fat, 23% protein, 45% carbohydrate) for 4-months. The three groups were matched for baseline age (56 ± 1 years), body mass index (BMI, 32.9 ± 0.7 kg/m(2)), and gender. Clinical measurements included whole-body norepinephrine kinetics, muscle sympathetic nerve activity (MSNA, by microneurography), spontaneous cardiac baroreflex sensitivity (BRS), and oral glucose tolerance test. Results: Weight loss averaged -7.5 ± 0.8, -8.1 ± 0.5, and -8.0 ± 0.9% of body weight in NGT, IGT, and T2D groups, respectively. T2D subjects had significantly greater reductions in fasting glucose, 2-h glucose and glucose area under the curve (AUC0-120) compared to NGT and IGT (group effect, P <0.001). Insulinogenic index decreased in IGT and NGT groups and increased in T2D (group × time, P = 0.04). The magnitude of reduction in MSNA (-7 ± 3, -8 ± 4, -15 ± 4 burst/100 hb, respectively) and whole-body norepinephrine spillover rate (-28 ± 8, -18 ± 6, and -25 ± 7%, respectively), time effect both P <0.001, did not differ between groups. After adjustment for age and change in body weight, Δ insulin AUC0-120 was independently associated with reduction in arterial norepinephrine concentration, whilst Δ LDL-cholesterol and improvement in BRS were independently associated with decrease in MSNA. Conclusions: Equivalent weight loss through hypocaloric diet is accompanied by similar sympathoinhibition in matched obese subjects with different

  1. Comparable Attenuation of Sympathetic Nervous System Activity in Obese Subjects with Normal Glucose Tolerance, Impaired Glucose Tolerance, and Treatment Naïve Type 2 Diabetes following Equivalent Weight Loss

    PubMed Central

    Straznicky, Nora E.; Grima, Mariee T.; Sari, Carolina I.; Lambert, Elisabeth A.; Phillips, Sarah E.; Eikelis, Nina; Mariani, Justin A.; Kobayashi, Daisuke; Hering, Dagmara; Dixon, John B.; Lambert, Gavin W.

    2016-01-01

    Background and Purpose: Elevated sympathetic nervous system (SNS) activity is a characteristic of obesity and type 2 diabetes (T2D) that contributes to target organ damage and cardiovascular risk. In this study we examined whether baseline metabolic status influences the degree of sympathoinhibition attained following equivalent dietary weight loss. Methods: Un-medicated obese individuals categorized as normal glucose tolerant (NGT, n = 15), impaired glucose tolerant (IGT, n = 24), and newly-diagnosed T2D (n = 15) consumed a hypocaloric diet (29% fat, 23% protein, 45% carbohydrate) for 4-months. The three groups were matched for baseline age (56 ± 1 years), body mass index (BMI, 32.9 ± 0.7 kg/m2), and gender. Clinical measurements included whole-body norepinephrine kinetics, muscle sympathetic nerve activity (MSNA, by microneurography), spontaneous cardiac baroreflex sensitivity (BRS), and oral glucose tolerance test. Results: Weight loss averaged −7.5 ± 0.8, −8.1 ± 0.5, and −8.0 ± 0.9% of body weight in NGT, IGT, and T2D groups, respectively. T2D subjects had significantly greater reductions in fasting glucose, 2-h glucose and glucose area under the curve (AUC0−120) compared to NGT and IGT (group effect, P <0.001). Insulinogenic index decreased in IGT and NGT groups and increased in T2D (group × time, P = 0.04). The magnitude of reduction in MSNA (−7 ± 3, −8 ± 4, −15 ± 4 burst/100 hb, respectively) and whole-body norepinephrine spillover rate (−28 ± 8, −18 ± 6, and −25 ± 7%, respectively), time effect both P <0.001, did not differ between groups. After adjustment for age and change in body weight, Δ insulin AUC0−120 was independently associated with reduction in arterial norepinephrine concentration, whilst Δ LDL-cholesterol and improvement in BRS were independently associated with decrease in MSNA. Conclusions: Equivalent weight loss through hypocaloric diet is accompanied by similar sympathoinhibition in matched obese subjects

  2. Brain stem activity changes associated with restored sympathetic drive following CPAP treatment in OSA subjects: a longitudinal investigation.

    PubMed

    Lundblad, Linda C; Fatouleh, Rania H; McKenzie, David K; Macefield, Vaughan G; Henderson, Luke A

    2015-08-01

    Obstructive sleep apnea (OSA) is associated with significantly elevated muscle sympathetic nerve activity (MSNA), leading to hypertension and increased cardiovascular morbidity. Although little is known about the mechanisms responsible for the sympathoexcitation, we have recently shown that the elevated MSNA in OSA is associated with altered neural processing in various brain stem sites, including the dorsolateral pons, rostral ventrolateral medulla, medullary raphe, and midbrain. Given the risk associated with elevated MSNA, we aimed to determine if treatment of OSA with continuous positive airway pressure (CPAP) would reduce the elevated MSNA and reverse the brain stem functional changes associated with the elevated MSNA. We performed concurrent recordings of MSNA and blood oxygen level-dependent (BOLD) signal intensity of the brain stem, using high-resolution functional magnetic resonance imaging, in 15 controls and 13 subjects with OSA, before and after 6 mo CPAP treatment. As expected, 6 mo of CPAP treatment significantly reduced MSNA in subjects with OSA, from 54 ± 4 to 23 ± 3 bursts/min and from 77 ± 7 to 36 ± 3 bursts/100 heart beats. Importantly, we found that MSNA-coupled changes in BOLD signal intensity within the dorsolateral pons, medullary raphe, and rostral ventrolateral medulla returned to control levels. That is, CPAP treatment completely reversed brain stem functional changes associated with elevated MSNA in untreated OSA subjects. These data highlight the effectiveness of CPAP treatment in reducing one of the most significant health issues associated with OSA, that is, elevated MSNA and its associated elevated morbidity.

  3. Cardiopulmonary baroreceptor control of muscle sympathetic nerve activity in heat-stressed humans

    NASA Technical Reports Server (NTRS)

    Crandall, C. G.; Etzel, R. A.; Farr, D. B.

    1999-01-01

    Whole body heating decreases central venous pressure (CVP) while increasing muscle sympathetic nerve activity (MSNA). In normothermia, similar decreases in CVP elevate MSNA, presumably via cardiopulmonary baroreceptor unloading. The purpose of this project was to identify whether increases in MSNA during whole body heating could be attributed to cardiopulmonary baroreceptor unloading coincident with the thermal challenge. Seven subjects were exposed to whole body heating while sublingual temperature, skin blood flow, heart rate, arterial blood pressure, and MSNA were monitored. During the heat stress, 15 ml/kg warmed saline was infused intravenously over 7-10 min to increase CVP and load the cardiopulmonary baroreceptors. We reported previously that this amount of saline was sufficient to return CVP to pre-heat stress levels. Whole body heating increased MSNA from 25 +/- 3 to 39 +/- 3 bursts/min (P < 0. 05). Central blood volume expansion via rapid saline infusion did not significantly decrease MSNA (44 +/- 4 bursts/min, P > 0.05 relative to heat stress period) and did not alter mean arterial blood pressure (MAP) or pulse pressure. To identify whether arterial baroreceptor loading decreases MSNA during heat stress, in a separate protocol MAP was elevated via steady-state infusion of phenylephrine during whole body heating. Increasing MAP from 82 +/- 3 to 93 +/- 4 mmHg (P < 0.05) caused MSNA to decrease from 36 +/- 3 to 15 +/- 4 bursts/min (P < 0.05). These data suggest that cardiopulmonary baroreceptor unloading during passive heating is not the primary mechanism resulting in elevations in MSNA. Moreover, arterial baroreceptors remain capable of modulating MSNA during heat stress.

  4. Sympathetic Activation is Associated with Exercise Limitation in COPD.

    PubMed

    Haarmann, Helge; Folle, Jan; Nguyen, Xuan Phuc; Herrmann, Peter; Heusser, Karsten; Hasenfuß, Gerd; Andreas, Stefan; Raupach, Tobias

    2016-10-01

    Exercise intolerance, skeletal muscle dysfunction, and reduced daily activity are central in COPD patients and closely related to quality of life and prognosis. Studies assessing muscle exercise have revealed an increase in sympathetic outflow as a link to muscle hypoperfusion and exercise limitation. Our primary hypothesis was that muscle sympathetic nerve activity (MSNA) correlates with exercise limitation in COPD. MSNA was evaluated at rest and during dynamic or static handgrip exercise. Additionally, we assessed heart rate, blood pressure, CO2 tension, oxygen saturation (SpO2), and breathing frequency. Ergospirometry was performed to evaluate exercise capacity. We assessed MSNA of 14 COPD patients and 8 controls. In patients, MSNA was negatively correlated with peak oxygen uptake (VO2% pred) (r = -0.597; p = 0.040). During dynamic or static handgrip exercise, patients exhibited a significant increase in MSNA, which was not observed in the control group. The increase in MSNA during dynamic handgrip was highly negatively correlated with peak exercise capacity in Watts (w) and peak oxygen uptake (VO2/kg) (r = -0.853; p = 0.002 and r = -0.881; p = 0.002, respectively). Our study reveals an association between increased MSNA and limited exercise capacity in patients with COPD. Furthermore, we found an increased sympathetic response to moderate physical exercise (handgrip), which may contribute to exercise intolerance in COPD.

  5. Lateralization of expression of neural sympathetic activity to the vessels and effects of carotid baroreceptor stimulation

    PubMed Central

    Diedrich, André; Porta, Alberto; Barbic, Franca; Brychta, Robert J.; Bonizzi, Pietro; Diedrich, Laura; Cerutti, Sergio; Robertson, David; Furlan, Raffaello

    2009-01-01

    Human studies suggest that cardiovascular neural sympathetic control is predominantly modulated by the right cerebral hemisphere. It is unknown whether post-ganglionic sympathetic activity [muscle sympathetic nerve activity (MSNA)] shows any functional asymmetry. Eight right-handed volunteers (3 women and 5 men, 32 ± 2 yr of age) underwent ECG, beat-by-beat blood pressure, respiratory activity, and simultaneous right and left MSNA recordings during spontaneous and controlled breathing (CB, 15 breaths/min, 0.25 Hz). Dynamic carotid baroreceptor stimulation was obtained by 0.1-Hz sinusoidal suction, from 0 to −50 mmHg, randomly applied to the right, left, and combined right and left sides of the neck during CB. Laterality was assessed by changes in the MSNA burst rate (in bursts/min, and bursts/100 beats), strength [amplitude (A) and area (AA)], and the oscillatory component at 0.1 Hz during baroreceptor stimulation. Amplitude parameters were normalized by CB burst mean amplitude and area of the same side. At rest, the right and left MSNA burst rate and total MSNA activity were similar. Conversely, the right MSNA normalized burst AN (1.36 ± 0.18) and AAN (1.31 ± 0.16) were larger than the left MSNA AN (1.04 ± 0.09) and AAN (1.02 ± 0.08). Unilateral and bilateral carotid baroreflex stimulation abolished the right prevalence of AN and AAN. In conclusion, the right lateralization of sympathetic activity to the vessels is indicated by normalized burst strength parameters of bilateral MSNA recordings at rest during spontaneous breathing. Carotid baroreceptor stimulation disrupted such expression of MSNA lateralization possibly by disturbing the synchronizing action of right cerebral hemisphere. PMID:19363133

  6. Interaction of the vestibular system and baroreflexes on sympathetic nerve activity in humans

    NASA Technical Reports Server (NTRS)

    Ray, C. A.

    2000-01-01

    Muscle sympathetic nerve activity (MSNA) is altered by vestibular otolith stimulation. This study examined interactive effects of the vestibular system and baroreflexes on MSNA in humans. In study 1, MSNA was measured during 4 min of lower body negative pressure (LBNP) at either -10 or -30 mmHg with subjects in prone posture. During the 3rd min of LBNP, subjects lowered their head over the end of a table (head-down rotation, HDR) to engage the otolith organs. The head was returned to baseline upright position during the 4th min. LBNP increased MSNA above baseline during both trials with greater increases during the -30-mmHg trial. HDR increased MSNA further during the 3rd min of LBNP at -10 and -30 mmHg (Delta32% and Delta34%, respectively; P < 0.01). MSNA returned to pre-HDR levels during the 4th min of LBNP when the head was returned upright. In study 2, MSNA was measured during HDR, LBNP, and simultaneously performed HDR and LBNP. The sum of MSNA responses during individual HDR and LBNP trials was not significantly different from that observed during HDR and LBNP performed together (Delta131 +/- 28 vs. Delta118 +/- 47 units and Delta340 +/- 77 vs. Delta380 +/- 90 units for the -10 and -30 trials, respectively). These results demonstrate that vestibular otolith stimulation can increase MSNA during unloading of the cardiopulmonary and arterial baroreflexes. Also, the interaction between the vestibulosympathetic reflex and baroreflexes is additive in humans. These studies indicate that the vestibulosympathetic reflex may help defend against orthostatic challenges in humans by increasing sympathetic outflow.

  7. Interaction between vestibulosympathetic and skeletal muscle reflexes on sympathetic activity in humans

    NASA Technical Reports Server (NTRS)

    Ray, C. A.

    2001-01-01

    Evidence from animals indicates that skeletal muscle afferents activate the vestibular nuclei and that both vestibular and skeletal muscle afferents have inputs to the ventrolateral medulla. The purpose of the present study was to investigate the interaction between the vestibulosympathetic and skeletal muscle reflexes on muscle sympathetic nerve activity (MSNA) and arterial pressure in humans. MSNA, arterial pressure, and heart rate were measured in 17 healthy subjects in the prone position during three experimental trials. The three trials were 2 min of 1) head-down rotation (HDR) to engage the vestibulosympathetic reflex, 2) isometric handgrip (IHG) at 30% maximal voluntary contraction to activate skeletal muscle afferents, and 3) HDR and IHG performed simultaneously. The order of the three trials was randomized. HDR and IHG performed alone increased total MSNA by 46 +/- 16 and 77 +/- 24 units, respectively (P < 0.01). During the HDR plus IHG trial, MSNA increased 142 +/- 38 units (P < 0.01). This increase was not significantly different from the sum of the individual trials (130 +/- 41 units). This finding was also observed with mean arterial pressure (sum = 21 +/- 2 mmHg and HDR + IHG = 22 +/- 2 mmHg). These findings suggest that there is an additive interaction for MSNA and arterial pressure when the vestibulosympathetic and skeletal muscle reflexes are engaged simultaneously in humans. Therefore, no central modulation exists between these two reflexes with regard to MSNA output in humans.

  8. Effect of pioglitazone on muscle sympathetic nerve activity in type 2 diabetes mellitus with α-glucosidase inhibitor.

    PubMed

    Kobayashi, Daisuke; Takamura, Masayuki; Murai, Hisayoshi; Usui, Soichiro; Ikeda, Tatsunori; Inomata, Jun-ichiro; Takashima, Shin-ichiro; Kato, Takeshi; Furusho, Hiroshi; Takeshita, Yumie; Ota, Tsuguhito; Takamura, Toshinari; Kaneko, Shuichi

    2010-12-08

    Activation of the sympathetic nervous system is augmented in patients with type 2 diabetes mellitus (DM). Pioglitazone, an anti-diabetic drug, improves insulin resistance, but its influence on sympathetic nerve activity is not clear. To identify the relationship between insulin resistance and sympathetic activity, we examined muscle sympathetic nerve activity (MSNA) in controlled type 2 DM patients with alpha-glucosidase inhibitor (GI). We measured MSNA and calculated homeostasis model assessment of insulin resistance index (HOMA-IR) in twelve DM patients treated with alpha-GI and thirteen age-matched healthy subjects. In DM patients with alpha-GI, all parameters were reexamined after three months of treatment with pioglitazone. MSNA and HOMA-IR were significantly greater in DM patients with alpha-GI compared to healthy subjects. Hemoglobin A1c did not differ in DM patients before and after pioglitazone. However, pioglitazone significantly decreased MSNA in DM patients compared with alpha-GI (21.7±5.2 vs. 32.0±6.8 burst/min, p<0.01). Furthermore, MSNA level in pioglitazone was similar to that in healthy subjects. HOMA-IR significantly decreased after pioglitazone, and a significant relationship was found between the absolute change in MSNA and HOMA-IR (r=0.65, p<0.05). These results suggest that improved insulin resistance with pioglitazone provides an additional effect on inhibition of sympathetic nerve activity.

  9. Muscle Sympathetic Nerve Activity Is Associated with Liver Insulin Sensitivity in Obese Non-Diabetic Men.

    PubMed

    Chen, Daniel L T; Brown, Rachael; Liess, Carsten; Poljak, Anne; Xu, Aimin; Zhang, Jialiang; Trenell, Michael; Jenkins, Arthur; Chisholm, Donald; Samocha-Bonet, Dorit; Macefield, Vaughan G; Greenfield, Jerry R

    2017-01-01

    Introduction: Muscle sympathetic nerve activity (MSNA) may play a role in insulin resistance in obesity. However, the direction and nature of the relationship between MSNA and insulin resistance in obesity remain unclear. We hypothesized that resting MSNA would correlate inversely with both muscle and liver insulin sensitivity and that it would be higher in insulin-resistant vs. insulin-sensitive subjects. Materials and methods: Forty-five non-diabetic obese subjects were studied. As no significant relationships were found in women, the data presented in on 22 men aged 48 ± 12 years. Two-step (15 and 80 mU/m(2)/min) hyperinsulinaemic-euglycaemic clamps were performed using deuterated glucose to determine liver and muscle insulin sensitivity. Clinical and metabolic parameters were assessed. MSNA was measured via a microelectrode inserted percutaneously into the common peroneal nerve. Results: MSNA burst frequency correlated inversely with liver insulin sensitivity (r = -0.53, P = 0.02) and positively with the hepatokines C-reactive protein (CRP) and fibroblast growth factor (FGF)-19 (r = 0.57, P = 0.006, and r = -0.47, P = 0.03, respectively). MSNA burst frequency was lower in Liversen compared to Liverres (27 ± 5 vs. 38 ± 2 bursts per minute; P = 0.03). Muscle insulin sensitivity was unrelated to MSNA. Discussion: Sympathetic neural activation is related to liver insulin sensitivity and circulating hepatokines CRP and FGF-19 in non-diabetic obese men. These results suggest a potential hepato-endocrine-autonomic axis. Future studies are needed to clarify the influence of MSNA on liver insulin sensitivity in men.

  10. Muscle Sympathetic Nerve Activity Is Associated with Liver Insulin Sensitivity in Obese Non-Diabetic Men

    PubMed Central

    Chen, Daniel L. T.; Brown, Rachael; Liess, Carsten; Poljak, Anne; Xu, Aimin; Zhang, Jialiang; Trenell, Michael; Jenkins, Arthur; Chisholm, Donald; Samocha-Bonet, Dorit; Macefield, Vaughan G.; Greenfield, Jerry R.

    2017-01-01

    Introduction: Muscle sympathetic nerve activity (MSNA) may play a role in insulin resistance in obesity. However, the direction and nature of the relationship between MSNA and insulin resistance in obesity remain unclear. We hypothesized that resting MSNA would correlate inversely with both muscle and liver insulin sensitivity and that it would be higher in insulin-resistant vs. insulin-sensitive subjects. Materials and methods: Forty-five non-diabetic obese subjects were studied. As no significant relationships were found in women, the data presented in on 22 men aged 48 ± 12 years. Two-step (15 and 80 mU/m2/min) hyperinsulinaemic-euglycaemic clamps were performed using deuterated glucose to determine liver and muscle insulin sensitivity. Clinical and metabolic parameters were assessed. MSNA was measured via a microelectrode inserted percutaneously into the common peroneal nerve. Results: MSNA burst frequency correlated inversely with liver insulin sensitivity (r = −0.53, P = 0.02) and positively with the hepatokines C-reactive protein (CRP) and fibroblast growth factor (FGF)-19 (r = 0.57, P = 0.006, and r = −0.47, P = 0.03, respectively). MSNA burst frequency was lower in Liversen compared to Liverres (27 ± 5 vs. 38 ± 2 bursts per minute; P = 0.03). Muscle insulin sensitivity was unrelated to MSNA. Discussion: Sympathetic neural activation is related to liver insulin sensitivity and circulating hepatokines CRP and FGF-19 in non-diabetic obese men. These results suggest a potential hepato-endocrine-autonomic axis. Future studies are needed to clarify the influence of MSNA on liver insulin sensitivity in men. PMID:28293196

  11. Baroreflex modulation of sympathetic nerve activity to muscle in heat-stressed humans

    NASA Technical Reports Server (NTRS)

    Cui, Jian; Wilson, Thad E.; Crandall, Craig G.

    2002-01-01

    To identify whether whole body heating alters arterial baroreflex control of muscle sympathetic nerve activity (MSNA), MSNA and beat-by-beat arterial blood pressure were recorded in seven healthy subjects during acute hypotensive and hypertensive stimuli in both normothermic and heat stress conditions. Whole body heating significantly increased sublingual temperature (P < 0.01), MSNA (P < 0.01), heart rate (P < 0.01), and skin blood flow (P < 0.001), whereas mean arterial blood pressure did not change significantly (P > 0.05). During both normothermic and heat stress conditions, MSNA increased and then decreased significantly when blood pressure was lowered and then raised via intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure during heat stress (-128.3 +/- 13.9 U x beats(-1) x mmHg(-1)) was similar (P = 0.31) with normothermia (-140.6 +/- 21.1 U x beats(-1) x mmHg(-1)). Moreover, no significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. These data suggest that arterial baroreflex modulation of MSNA and heart rate are not altered by whole body heating, with the exception of an upward shift of these baroreflex curves to accommodate changes in these variables that occur with whole body heating.

  12. Seasonal variation in muscle sympathetic nerve activity

    PubMed Central

    Cui, Jian; Muller, Matthew D; Blaha, Cheryl; Kunselman, Allen R; Sinoway, Lawrence I

    2015-01-01

    Epidemiologic data suggest there are seasonal variations in the incidence of severe cardiac events with peak levels being evident in the winter. Whether autonomic indices including muscle sympathetic nerve activity (MSNA) vary with season remains unclear. In this report, we tested the hypothesis that resting MSNA varies with the seasons of the year with peak levels evident in the winter. We analyzed the supine resting MSNA in 60 healthy subjects. Each subject was studied during two, three, or four seasons (total 237 visits). MSNA burst rate in the winter (21.0 ± 6.8 burst/min, mean ± SD) was significantly greater than in the summer (13.5 ± 5.8 burst/min, P < 0.001), the spring (17.1 ± 9.0 burst/min, P = 0.03), and the fall (17.9 ± 7.7 burst/min, P = 0.002). There was no significant difference in MSNA for other seasonal comparisons. The results suggest that resting sympathetic nerve activity varies along the seasons, with peak levels evident in the winter. We speculate that the seasonal changes in sympathetic activity may be a contribution to the previously observed seasonal variations in cardiovascular morbidity and mortality. PMID:26265752

  13. Vestibular control of sympathetic activity. An otolith-sympathetic reflex in humans

    NASA Technical Reports Server (NTRS)

    Kaufmann, H.; Biaggioni, I.; Voustianiouk, A.; Diedrich, A.; Costa, F.; Clarke, R.; Gizzi, M.; Raphan, T.; Cohen, B.

    2002-01-01

    It has been proposed that a vestibular reflex originating in the otolith organs and other body graviceptors modulates sympathetic activity during changes in posture with regard to gravity. To test this hypothesis, we selectively stimulated otolith and body graviceptors sinusoidally along different head axes in the coronal plane with off-vertical axis rotation (OVAR) and recorded sympathetic efferent activity in the peroneal nerve (muscle sympathetic nerve activity, MSNA), blood pressure, heart rate, and respiratory rate. All parameters were entrained during OVAR at the frequency of rotation, with MSNA increasing in nose-up positions during forward linear acceleration and decreasing when nose-down. MSNA was correlated closely with blood pressure when subjects were within +/-90 degrees of nose-down positions with a delay of 1.4 s, the normal latency of baroreflex-driven changes in MSNA. Thus, in the nose-down position, MSNA was probably driven by baroreflex afferents. In contrast, when subjects were within +/-45 degrees of the nose-up position, i.e., when positive linear acceleration was maximal along the naso-ocipital axis, MSNA was closely related to gravitational acceleration at a latency of 0.4 s. This delay is too short for MSNA changes to be mediated by the baroreflex, but it is compatible with the delay of a response originating in the vestibular system. We postulate that a vestibulosympathetic reflex, probably originating mainly in the otolith organs, contributes to blood pressure maintenance during forward linear acceleration. Because of its short latency, this reflex may be one of the earliest mechanisms to sustain blood pressure upon standing.

  14. Reduced sympathetic nervous activity. A potential mechanism predisposing to body weight gain.

    PubMed Central

    Spraul, M; Ravussin, E; Fontvieille, A M; Rising, R; Larson, D E; Anderson, E A

    1993-01-01

    The sympathetic nervous system is recognized to play a role in the etiology of animal and possibly human obesity through its impact on energy expenditure and/or food intake. We, therefore, measured fasting muscle sympathetic nerve activity (MSNA) in the peroneal nerve and its relationship with energy expenditure and body composition in 25 relatively lean Pima Indian males (means +/- SD; 26 +/- 6 yr, 82 +/- 19 kg, 28 +/- 10% body fat) and 19 Caucasian males (29 +/- 5 yr, 81 +/- 13 kg, 24 +/- 9% body fat). 24-h energy expenditure, sleeping metabolic rate, and resting metabolic rate were measured in a respiratory chamber, whereas body composition was estimated by hydrodensitometry. Pima Indians had lower MSNA than Caucasians (23 +/- 6 vs 33 +/- 10 bursts/min, P = 0.0007). MSNA was significantly related to percent body fat in Caucasians (r = 0.55, P = 0.01) but not in Pimas. MSNA also correlated with energy expenditure adjusted for fat-free mass, fat mass, and age in Caucasians (r = 0.51, P = 0.03; r = 0.54, P = 0.02; and r = 0.53, P = 0.02 for adjusted 24-h energy expenditure, sleeping metabolic rate, and resting metabolic rate, respectively) but not in Pima Indians. In conclusion, the activity of the sympathetic nervous system is a determinant of energy expenditure in Caucasians. Individuals with low resting MSNA may be at risk for body weight gain resulting from a lower metabolic rate. A low resting MSNA and the lack of impact of MSNA on metabolic rate might play a role in the etiology of obesity in Pima Indians. PMID:8408625

  15. Cigarette smoking augments sympathetic nerve activity in patients with coronary heart disease.

    PubMed

    Shinozaki, Norihiko; Yuasa, Toyoshi; Takata, Shigeo

    2008-05-01

    It has been shown that cigarette smoking increases blood pressure (BP) and heart rate (HR), and decreases muscle sympathetic nerve activity (MSNA) in healthy young smokers. The decrease in MSNA might be secondary to baroreflex responses to the pressor effect. We tested the hypothesis that cigarette smoking increases MSNA in smokers with impaired baroreflex function. The effects of cigarette smoking on BP, HR, forearm blood flow (FBF), forearm vascular resistance (FVR), and MSNA were examined in 14 patients with stable effort angina (59+/-3 years, group CAD) and 10 healthy smokers (23+/-1 years, group C). In group CAD, the arterial baroreflex sensitivity (BRS) was significantly lower than in group C (4.7+/-0.8 versus 15.1+/-2.2 msec/mmHg, P<0.01). In both groups, cigarette smoking increased the plasma concentration of nicotine, systolic and diastolic BP, HR, and FVR significantly (P<0.01), but decreased FBF significantly (P<0.01). After smoking, MSNA was decreased significantly in group C (from 35.2+/-3.5 to 23.5+/-3.2 bursts/100 beats, P<0.01), but increased significantly in group CAD (from 48.8+/-5.4 to 57.3+/-5.5 bursts/100 beats, P<0.01). There was significant correlation between BRS and changes in MSNA (r= -0.62, P<0.01). Cigarette smoking increased MSNA in smokers with impaired baroreflex function. This demonstrates that cigarette smoking stimulates sympathetic nerve activity by both a direct peripheral effect and a centrally mediated effect.

  16. Heart rate variability and muscle sympathetic nerve activity response to acute stress: the effect of breathing

    PubMed Central

    DeBeck, Lindsay D.; Petersen, Stewart R.; Jones, Kelvin E.; Stickland, Michael K.

    2016-01-01

    Previous research has suggested a relationship between low-frequency power of heart rate variability (HRV; LF in normalized units, LFnu) and muscle sympathetic nerve activity (MSNA). However, investigations have not systematically controlled for breathing, which can modulate both HRV and MSNA. Accordingly, the aims of this experiment were to investigate the possibility of parallel responses in MSNA and HRV (LFnu) to selected acute stressors and the effect of controlled breathing. After data were obtained at rest, 12 healthy males (28 ± 5 yr) performed isometric handgrip exercise (30% maximal voluntary contraction) and the cold pressor test in random order, and were then exposed to hypoxia (inspired fraction of O2 = 0.105) for 7 min, during randomly assigned spontaneous and controlled breathing conditions (20 breaths/min, constant tidal volume, isocapnic). MSNA was recorded from the peroneal nerve, whereas HRV was calculated from ECG. At rest, controlled breathing did not alter MSNA but decreased LFnu (P < 0.05 for all) relative to spontaneous breathing. MSNA increased in response to all stressors regardless of breathing. LFnu increased with exercise during both breathing conditions. During cold pressor, LFnu decreased when breathing was spontaneous, whereas in the controlled breathing condition, LFnu was unchanged from baseline. Hypoxia elicited increases in LFnu when breathing was controlled, but not during spontaneous breathing. The parallel changes observed during exercise and controlled breathing during hypoxia suggest that LFnu may be an indication of sympathetic outflow in select conditions. However, since MSNA and LFnu did not change in parallel with all stressors, a cautious approach to the use of LFnu as a marker of sympathetic activity is warranted. PMID:20410469

  17. Heart rate variability and muscle sympathetic nerve activity response to acute stress: the effect of breathing.

    PubMed

    DeBeck, Lindsay D; Petersen, Stewart R; Jones, Kelvin E; Stickland, Michael K

    2010-07-01

    Previous research has suggested a relationship between low-frequency power of heart rate variability (HRV; LF in normalized units, LFnu) and muscle sympathetic nerve activity (MSNA). However, investigations have not systematically controlled for breathing, which can modulate both HRV and MSNA. Accordingly, the aims of this experiment were to investigate the possibility of parallel responses in MSNA and HRV (LFnu) to selected acute stressors and the effect of controlled breathing. After data were obtained at rest, 12 healthy males (28 +/- 5 yr) performed isometric handgrip exercise (30% maximal voluntary contraction) and the cold pressor test in random order, and were then exposed to hypoxia (inspired fraction of O(2) = 0.105) for 7 min, during randomly assigned spontaneous and controlled breathing conditions (20 breaths/min, constant tidal volume, isocapnic). MSNA was recorded from the peroneal nerve, whereas HRV was calculated from ECG. At rest, controlled breathing did not alter MSNA but decreased LFnu (P < 0.05 for all) relative to spontaneous breathing. MSNA increased in response to all stressors regardless of breathing. LFnu increased with exercise during both breathing conditions. During cold pressor, LFnu decreased when breathing was spontaneous, whereas in the controlled breathing condition, LFnu was unchanged from baseline. Hypoxia elicited increases in LFnu when breathing was controlled, but not during spontaneous breathing. The parallel changes observed during exercise and controlled breathing during hypoxia suggest that LFnu may be an indication of sympathetic outflow in select conditions. However, since MSNA and LFnu did not change in parallel with all stressors, a cautious approach to the use of LFnu as a marker of sympathetic activity is warranted.

  18. Cardiopulmonary baroreflex inhibition of sympathetic nerve activity is preserved with age in healthy humans.

    PubMed

    Tanaka, H; Davy, K P; Seals, D R

    1999-02-15

    1. We tested the hypothesis that the ability of the cardiopulmonary baroreflex to produce sympathoinhibition is reduced with age in humans. Eleven young (23 +/- 1 years, mean +/- s.e.m.) and ten older (64 +/- 1) healthy adult males were studied under supine conditions (control) and in response to cardiopulmonary baroreflex stimulation evoked by acute central circulatory hypervolaemia (10 deg head-down tilt). The two groups were normotensive and free of overt cardiovascular disease. 2. Supine baseline (control) levels of efferent muscle sympathetic nerve activity (MSNA) burst frequency were twice as high in the older men (41 +/- 2 vs. 21 +/- 2 bursts min-1, P < 0.05). In both groups in response to head-down tilt arterial blood pressure and heart rate were unchanged, peripheral venous pressure (PVP) increased (P < 0.05), MSNA total activity decreased (P < 0.05), antecubital venous plasma noradrenaline concentrations did not change significantly, and forearm blood flow and vascular conductance increased (vascular resistance decreased) (all P < 0.05). The mean absolute DeltaMSNA/DeltaPVP was similar in the young and older men, although the higher control levels of MSNA in the older men resulted in a smaller percentage DeltaMSNA/DeltaPVP (P < 0.05). Per DeltaPVP, the reduction in forearm vascular resistance was smaller in the older men, but there were no age group differences when expressed as increases in forearm vascular conductance. 3. These results indicate that the ability of the cardiopulmonary baroreflex to inhibit MSNA is well preserved with age in healthy adult humans. As such, these findings are not consistent with the concept that this mechanism plays a role in the age-associated elevation in basal MSNA.

  19. Regulation of muscle sympathetic nerve activity after bed rest deconditioning

    NASA Technical Reports Server (NTRS)

    Pawelczyk, J. A.; Zuckerman, J. H.; Blomqvist, C. G.; Levine, B. D.

    2001-01-01

    Cardiovascular deconditioning reduces orthostatic tolerance. To determine whether changes in autonomic function might produce this effect, we developed stimulus-response curves relating limb vascular resistance, muscle sympathetic nerve activity (MSNA), and pulmonary capillary wedge pressure (PCWP) with seven subjects before and after 18 days of -6 degrees head-down bed rest. Both lower body negative pressure (LBNP; -15 and -30 mmHg) and rapid saline infusion (15 and 30 ml/kg body wt) were used to produce a wide variation in PCWP. Orthostatic tolerance was assessed with graded LBNP to presyncope. Bed rest reduced LBNP tolerance from 23.9 +/- 2.1 to 21.2 +/- 1.5 min, respectively (means +/- SE, P = 0.02). The MSNA-PCWP relationship was unchanged after bed rest, though at any stage of the LBNP protocol PCWP was lower, and MSNA was greater. Thus bed rest deconditioning produced hypovolemia, causing a shift in operating point on the stimulus-response curve. The relationship between limb vascular resistance and MSNA was not significantly altered after bed rest. We conclude that bed rest deconditioning does not alter reflex control of MSNA, but may produce orthostatic intolerance through a combination of hypovolemia and cardiac atrophy.

  20. Influence of age and sex on the pressor response following a spontaneous burst of muscle sympathetic nerve activity

    PubMed Central

    Vianna, Lauro C.; Hart, Emma C.; Fairfax, Seth T.; Charkoudian, Nisha; Joyner, Michael J.

    2012-01-01

    The sympathetic nervous system is critical for the beat-to-beat regulation of arterial blood pressure (BP). Although studies have examined age- and sex-related effects on BP control, findings are inconsistent and limited data are available in postmenopausal women. In addition, the majority of studies have focused on time-averaged responses without consideration for potential beat-to-beat alterations. Thus we examined whether the ability of muscle sympathetic nerve activity (MSNA) to modulate BP on a beat-to-beat basis is affected by age or sex. BP and MSNA were measured during supine rest in 40 young (20 men) and 40 older (20 men) healthy subjects. Beat-to-beat fluctuations in mean arterial pressure (MAP) were characterized for 15 cardiac cycles after each MSNA burst using signal averaging. The rise in MAP following an MSNA burst was similar between young men and women (+2.64 ± 0.3 vs. +2.57 ± 0.3 mmHg, respectively). However, the magnitude of the increase in MAP after an MSNA burst was reduced in older compared with young subjects (P < 0.05). Moreover, the attenuation of the pressor response was greater in older women (+1.20 ± 0.1 mmHg) compared with older men (+1.72 ± 0.2 mmHg; P < 0.05). Interestingly, in all groups, MAP consistently decreased after cardiac cycles without MSNA bursts (nonbursts) with the magnitude of fall greatest in older men. In summary, healthy aging is associated with an attenuated beat-to-beat increase in BP after a spontaneous MSNA burst, and this attenuation is more pronounced in postmenopausal women. Furthermore, our nonburst findings highlight the importance of sympathetic vasoconstrictor activity to maintain beat-to-beat BP, particularly in older men. PMID:22427525

  1. Whole body heating reduces the baroreflex response of sympathetic nerve activity during Valsalva straining.

    PubMed

    Yamazaki, Fumio; Yamauchi, Katsuya; Tsutsui, Yuka; Endo, Yutaka; Sagawa, Sueko; Shiraki, Keizo

    2003-01-31

    The present experiment was carried out to examine the possible effects of whole body heating on the baroreflex control of muscle sympathetic nerve activity (MSNA) and heart rate (HR). Nine healthy male volunteers underwent the Valsalva maneuver during exposure to heat stress using a hot water-perfused suit. To exclude an effect from the unloading of the cardiopulmonary baroreceptors during hyperthermia, the central hypovolemia was counterbalanced by head-down tilt (HDT) at 8 degrees. The baroreflex slopes of MSNA and HR against mean arterial pressure were determined by regression analysis during the early phase II (falling blood pressure period) of the Valsalva maneuver. The core temperature increased from 36.9 +/- 0.1 degrees C at thermoneutral to 37.7 +/- 0.1 degrees C during heat exposure, whereas the left atrial diameter (LAD) decreased. Both the MSNA and HR increased (P < 0.05) during hyperthermia. The baroreflex slopes of MSNA and HR in the phase II decreased 30 +/- 8% (P < 0.05) and 24 +/- 9% (P < 0.05), respectively, during hyperthermia. The HDT increased LAD, but there was no change in HR, arterial pressure and the baroreflex slopes. These results suggest that hyperthermia reduces the baroreflex responses of MSNA and HR during a transient falling period of blood pressure. These reduced baroreflex responses may not be attributable to an unloading of the cardiopulmonary baroreceptors during heat stress.

  2. Baroreflex modulation of muscle sympathetic nerve activity during cold pressor test in humans

    NASA Technical Reports Server (NTRS)

    Cui, Jian; Wilson, Thad E.; Crandall, Craig G.

    2002-01-01

    The purpose of this project was to test the hypothesis that baroreceptor modulation of muscle sympathetic nerve activity (MSNA) and heart rate is altered during the cold pressor test. Ten subjects were exposed to a cold pressor test by immersing a hand in ice water for 3 min while arterial blood pressure, heart rate, and MSNA were recorded. During the second and third minute of the cold pressor test, blood pressure was lowered and then raised by intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure was more negative (P < 0.005) during the cold pressor test (-244.9 +/- 26.3 units x beat(-1) x mmHg(-1)) when compared with control conditions (-138.8 +/- 18.6 units x beat(-1) x mmHg(-1)), whereas no significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. These data suggest that baroreceptors remain capable of modulating MSNA and heart rate during a cold pressor test; however, the sensitivity of baroreflex modulation of MSNA is elevated without altering the sensitivity of baroreflex control of heart rate.

  3. Baroreflex modulation of muscle sympathetic nerve activity during posthandgrip muscle ischemia in humans

    NASA Technical Reports Server (NTRS)

    Cui, J.; Wilson, T. E.; Shibasaki, M.; Hodges, N. A.; Crandall, C. G.

    2001-01-01

    To identify whether muscle metaboreceptor stimulation alters baroreflex control of muscle sympathetic nerve activity (MSNA), MSNA, beat-by-beat arterial blood pressure (Finapres), and electrocardiogram were recorded in 11 healthy subjects in the supine position. Subjects performed 2 min of isometric handgrip exercise at 40% of maximal voluntary contraction followed by 2.5 min of posthandgrip muscle ischemia. During muscle ischemia, blood pressure was lowered and then raised by intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure was more negative (P < 0.001) during posthandgrip muscle ischemia (-201.9 +/- 20.4 units. beat(-1). mmHg(-1)) when compared with control conditions (-142.7 +/- 17.3 units. beat(-1). mmHg(-1)). No significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. However, both curves shifted during postexercise ischemia to accommodate the elevation in blood pressure and MSNA that occurs with this condition. These data suggest that the sensitivity of baroreflex modulation of MSNA is elevated by muscle metaboreceptor stimulation, whereas the sensitivity of baroreflex of modulate heart rate is unchanged during posthandgrip muscle ischemia.

  4. Baroreflex modulation of muscle sympathetic nerve activity at rest does not differ between morning and afternoon

    PubMed Central

    Hissen, Sarah L.; Macefield, Vaughan G.; Brown, Rachael; Witter, Trevor; Taylor, Chloe E.

    2015-01-01

    The incidence of cardiovascular events is significantly higher in the morning than other times of day. This has previously been associated with poor blood pressure control via the cardiac baroreflex. However, it is not known whether diurnal variation exists in vascular sympathetic baroreflex function, in which blood pressure is regulated via muscle sympathetic nerve activity (MSNA). The aim of this study was to compare vascular sympathetic baroreflex sensitivity (BRS) in the same participants between the morning and afternoon. In 10 participants (mean age 22 ± 2.9 years), continuous measurements of blood pressure, heart rate and MSNA were made during 10 min of rest in the morning (between 0900 and 1000 h) and afternoon (between 1400 and 1500 h). Spontaneous vascular sympathetic BRS was quantified by plotting MSNA burst incidence against diastolic pressure (vascular sympathetic BRSinc), and by plotting total MSNA against diastolic pressure (vascular sympathetic BRStotal). Significant vascular sympathetic BRSinc and vascular sympathetic BRStotal slopes were obtained for 10 participants at both times of day. There was no significant difference in vascular sympathetic BRSinc between morning (−2.2 ± 0.6% bursts/mmHg) and afternoon (−2.5 ± 0.2% bursts/mmHg; P = 0.68) sessions. Similarly, vascular sympathetic BRStotal did not differ significantly between the morning (−3.0±0.5 AU/beat/mmHg) and afternoon (−2.9 ± 0.4 AU/beat/mmHg; P = 0.89). It is concluded that in healthy, young individuals baroreflex modulation of MSNA at rest does not differ between the morning and afternoon. The results indicate that recording MSNA at different times of the day is a valid means of assessing sympathetic function. PMID:26388723

  5. Slow and deep respiration suppresses steady-state sympathetic nerve activity in patients with chronic heart failure: from modeling to clinical application.

    PubMed

    Harada, Daisuke; Asanoi, Hidetsugu; Takagawa, Junya; Ishise, Hisanari; Ueno, Hiroshi; Oda, Yoshitaka; Goso, Yukiko; Joho, Shuji; Inoue, Hiroshi

    2014-10-15

    Influences of slow and deep respiration on steady-state sympathetic nerve activity remain controversial in humans and could vary depending on disease conditions and basal sympathetic nerve activity. To elucidate the respiratory modulation of steady-state sympathetic nerve activity, we modeled the dynamic nature of the relationship between lung inflation and muscle sympathetic nerve activity (MSNA) in 11 heart failure patients with exaggerated sympathetic outflow at rest. An autoregressive exogenous input model was utilized to simulate entire responses of MSNA to variable respiratory patterns. In another 18 patients, we determined the influence of increasing tidal volume and slowing respiratory frequency on MSNA; 10 patients underwent a 15-min device-guided slow respiration and the remaining 8 had no respiratory modification. The model predicted that a 1-liter, step increase of lung volume decreased MSNA dynamically; its nadir (-33 ± 22%) occurred at 2.4 s; and steady-state decrease (-15 ± 5%), at 6 s. Actually, in patients with the device-guided slow and deep respiration, respiratory frequency effectively fell from 16.4 ± 3.9 to 6.7 ± 2.8/min (P < 0.0001) with a concomitant increase in tidal volume from 499 ± 206 to 1,177 ± 497 ml (P < 0.001). Consequently, steady-state MSNA was decreased by 31% (P < 0.005). In patients without respiratory modulation, there were no significant changes in respiratory frequency, tidal volume, and steady-state MSNA. Thus slow and deep respiration suppresses steady-state sympathetic nerve activity in patients with high levels of resting sympathetic tone as in heart failure.

  6. Gender affects sympathetic and hemodynamic response to postural stress

    NASA Technical Reports Server (NTRS)

    Shoemaker, J. K.; Hogeman, C. S.; Khan, M.; Kimmerly, D. S.; Sinoway, L. I.

    2001-01-01

    We tested the hypothesis that differences in sympathetic reflex responses to head-up tilt (HUT) between males (n = 9) and females (n = 8) were associated with decrements in postural vasomotor responses in women. Muscle sympathetic nerve activity (MSNA; microneurography), heart rate, stroke volume (SV; Doppler), and blood pressure (Finapres) were measured during a progressive HUT protocol (5 min at each of supine, 20 degrees, 40 degrees, and 60 degrees ). MSNA and hemodynamic responses were also measured during the cold pressor test (CPT) to examine nonbaroreflex neurovascular control. SV was normalized to body surface area (SV(i)) to calculate the index of cardiac output (Q(i)), and total peripheral resistance (TPR). During HUT, heart rate increased more in females versus males (P < 0.001) and SV(i) and Q(i) decreased similarly in both groups. Mean arterial pressure (MAP) increased to a lesser extent in females versus males in the HUT (P < 0.01) but increases in TPR during HUT were similar. MSNA burst frequency was lower in females versus males in supine (P < 0.03) but increased similarly during HUT. Average amplitude/burst increased in 60 degrees HUT for males but not females. Both males and females demonstrated an increase in MAP as well as MSNA burst frequency, mean burst amplitude, and total MSNA during the CPT. However, compared with females, males demonstrated a greater neural response (DeltaTotal MSNA) due to a larger increase in mean burst amplitude (P < 0.05). Therefore, these data point to gender-specific autonomic responses to cardiovascular stress. The different MSNA response to postural stress between genders may contribute importantly to decrements in blood pressure control during HUT in females.

  7. Sympathetic overactivity in active ulcerative colitis: effects of clonidine.

    PubMed

    Furlan, Raffaello; Ardizzone, Sandro; Palazzolo, Laura; Rimoldi, Alexandra; Perego, Francesca; Barbic, Franca; Bevilacqua, Maurizio; Vago, Luca; Bianchi Porro, Gabriele; Malliani, Alberto

    2006-01-01

    Previous reports suggest that inflammatory bowel diseases may be accompanied by abnormalities in the neural autonomic profile. We tested the hypotheses that 1) an exaggerated sympathetic activity characterizes active ulcerative colitis (UC) and 2) a reduction of sympathetic activity by clonidine would be associated with clinical changes of UC. In 23 patients with UC and 20 controls, muscle sympathetic nerve activity (MSNA), ECG, blood pressure, and respiration were continuously recorded, and plasma catecholamine was evaluated both at rest and during a 75 degrees head-up tilt. Autonomic profile was assessed by MSNA, norepinephrine, epinephrine, spectral markers of low-frequency (LF) cardiac sympathetic (LF(RR); normalized units) and high-frequency (HF) parasympathetic (HF(RR); normalized units) modulation and sympathetic vasomotor control (LF systolic arterial pressure; LF(SAP)), obtained by spectrum analysis of the R-R interval and systolic pressure variability. Among UC patients, 16 agreed to be randomly assigned to 8-wk transdermal clonidine (15 mg/wk, 9 subjects), or placebo (7 patients). An autonomic profile, Disease Activity Index (DAI), and endoscopic pattern were compared before and after clonidine/placebo. At rest, MSNA, heart rate (HR), LF(RR), LF/HF, and LF(SAP) were higher and HF(RR) was lower in patients than in controls. Tilt decreased HF(RR) and increased MSNA and LF(RR) less in patients than in controls. Clonidine decreased HR, MSNA, epinephrine, LF(RR), and increased HF(RR), whereas placebo had no effects. Changes of the autonomic profile after clonidine were associated with reduction of DAI score. An overall increase of sympathetic activity characterized active UC. Normalization of the autonomic profile by clonidine was accompanied by an improvement of the disease.

  8. Enhanced muscle pump during mild dynamic leg exercise inhibits sympathetic vasomotor outflow

    PubMed Central

    Katayama, Keisho; Ishida, Koji; Saito, Mitsuru; Koike, Teruhiko; Hirasawa, Ai; Ogoh, Shigehiko

    2014-01-01

    Abstract Muscle sympathetic nerve activity (MSNA) is not increased during leg cycling at light and mild intensities, despite activation of central command and the exercise pressor reflex. We determined whether increasing central blood volume and loading the cardiopulmonary baroreceptors modulate sympathetic vasomotor outflow during leg cycling. To this end, we changed the pedaling frequency to enhance skeletal muscle pump. Subjects performed two leg cycle exercises at differential pedal rates of 60 and 80 rpm (60EX and 80EX trials) for two conditions (with and without MSNA measurement). In each trial, subjects completed leg cycling with a differential workload to maintain constant oxygen consumption (VO2). MSNA was recorded via microneurography at the right median nerve of the elbow. Without MSNA measurement, thoracic impedance, stroke volume (SV), and cardiac output (CO) were measured non‐invasively using impedance cardiography. Heart rate and VO2 during exercise did not differ between the 60EX and 80EX trials. Changes in thoracic impedance, SV, and CO during the 80EX trial were greater than during the 60EX trial. MSNA during the 60EX trial was unchanged compared with that at rest (25.8 ± 3.1 [rest] to 28.3 ± 3.4 [exercise] bursts/min), whereas a significant decrease in MSNA was observed during the 80EX trial (25.8 ± 2.8 [rest] to 19.7 ± 2.0 [exercise] bursts/min). These results suggest that a muscle pump‐induced increase in central blood volume, and thereby loading of cardiopulmonary baroreceptors, could inhibit sympathetic vasomotor outflow during mild dynamic leg exercise, despite activation of central command and the exercise pressor reflex. PMID:25347854

  9. The role of α-adrenergic receptors in mediating beat-by-beat sympathetic vascular transduction in the forearm of resting man.

    PubMed

    Fairfax, Seth T; Holwerda, Seth W; Credeur, Daniel P; Zuidema, Mozow Y; Medley, John H; Dyke, Peter C; Wray, D Walter; Davis, Michael J; Fadel, Paul J

    2013-07-15

    Sympathetic vascular transduction is commonly understood to act as a basic relay mechanism, but under basal conditions, competing dilatory signals may interact with and alter the ability of sympathetic activity to decrease vascular conductance. Thus, we determined the extent to which spontaneous bursts of muscle sympathetic nerve activity (MSNA) mediate decreases in forearm vascular conductance (FVC) and the contribution of local α-adrenergic receptor-mediated pathways to the observed FVC responses. In 19 young men, MSNA (microneurography), arterial blood pressure and brachial artery blood flow (duplex Doppler ultrasound) were continuously measured during supine rest. These measures were also recorded in seven men during intra-arterial infusions of normal saline, phentolamine (PHEN) and PHEN with angiotensin II (PHEN+ANG). The latter was used to control for increases in resting blood flow with α-adrenergic blockade. Spike-triggered averaging was used to characterize beat-by-beat changes in FVC for 15 cardiac cycles following each MSNA burst and a peak response was calculated. Following MSNA bursts, FVC initially increased by +3.3 ± 0.3% (P = 0.016) and then robustly decreased to a nadir of -5.8 ± 1.6% (P < 0.001). The magnitude of vasoconstriction appeared graded with the number of consecutive MSNA bursts; while individual burst size only had a mild influence. Neither PHEN nor PHEN+ANG infusions affected the initial rise in FVC, but both infusions significantly attenuated the subsequent decrease in FVC (-2.1 ± 0.7% and -0.7 ± 0.8%, respectively; P < 0.001 vs. normal saline). These findings indicate that spontaneous MSNA bursts evoke robust beat-by-beat decreases in FVC that are exclusively mediated via α-adrenergic receptors.

  10. Molecular basis for the improvement in muscle metaboreflex and mechanoreflex control in exercise-trained humans with chronic heart failure

    PubMed Central

    Antunes-Correa, Ligia M.; Nobre, Thais S.; Groehs, Raphaela V.; Alves, Maria Janieire N. N.; Fernandes, Tiago; Couto, Gisele K.; Rondon, Maria Urbana P. B.; Oliveira, Patricia; Lima, Marta; Mathias, Wilson; Brum, Patricia C.; Mady, Charles; Almeida, Dirceu R.; Rossoni, Luciana V.; Oliveira, Edilamar M.; Middlekauff, Holly R.

    2014-01-01

    Previous studies have demonstrated that muscle mechanoreflex and metaboreflex controls are altered in heart failure (HF), which seems to be due to changes in cyclooxygenase (COX) pathway and changes in receptors on afferent neurons, including transient receptor potential vanilloid type-1 (TRPV1) and cannabinoid receptor type-1 (CB1). The purpose of the present study was to test the hypotheses: 1) exercise training (ET) alters the muscle metaboreflex and mechanoreflex control of muscle sympathetic nerve activity (MSNA) in HF patients. 2) The alteration in metaboreflex control is accompanied by increased expression of TRPV1 and CB1 receptors in skeletal muscle. 3) The alteration in mechanoreflex control is accompanied by COX-2 pathway in skeletal muscle. Thirty-four consecutive HF patients with ejection fractions <40% were randomized to untrained (n = 17; 54 ± 2 yr) or exercise-trained (n = 17; 56 ± 2 yr) groups. MSNA was recorded by microneurography. Mechanoreceptors were activated by passive exercise and metaboreceptors by postexercise circulatory arrest (PECA). COX-2 pathway, TRPV1, and CB1 receptors were measured in muscle biopsies. Following ET, resting MSNA was decreased compared with untrained group. During PECA (metaboreflex), MSNA responses were increased, which was accompanied by the expression of TRPV1 and CB1 receptors. During passive exercise (mechanoreflex), MSNA responses were decreased, which was accompanied by decreased expression of COX-2, prostaglandin-E2 receptor-4, and thromboxane-A2 receptor and by decreased in muscle inflammation, as indicated by increased miRNA-146 levels and the stable NF-κB/IκB-α ratio. In conclusion, ET alters muscle metaboreflex and mechanoreflex control of MSNA in HF patients. This alteration with ET is accompanied by alteration in TRPV1 and CB1 expression and COX-2 pathway and inflammation in skeletal muscle. PMID:25305179

  11. Isometric handgrip training reduces arterial pressure at rest without changes in sympathetic nerve activity

    NASA Technical Reports Server (NTRS)

    Ray, C. A.; Carrasco, D. I.

    2000-01-01

    The purpose of this study was to determine whether isometric handgrip (IHG) training reduces arterial pressure and whether reductions in muscle sympathetic nerve activity (MSNA) mediate this drop in arterial pressure. Normotensive subjects were assigned to training (n = 9), sham training (n = 7), or control (n = 8) groups. The training protocol consisted of four 3-min bouts of IHG exercise at 30% of maximal voluntary contraction (MVC) separated by 5-min rest periods. Training was performed four times per week for 5 wk. Subjects' resting arterial pressure and heart rate were measured three times on 3 consecutive days before and after training, with resting MSNA (peroneal nerve) recorded on the third day. Additionally, subjects performed IHG exercise at 30% of MVC to fatigue followed by muscle ischemia. In the trained group, resting diastolic (67 +/- 1 to 62 +/- 1 mmHg) and mean arterial pressure (86 +/- 1 to 82 +/- 1 mmHg) significantly decreased, whereas systolic arterial pressure (116 +/- 3 to 113 +/- 2 mmHg), heart rate (67 +/- 4 to 66 +/- 4 beats/min), and MSNA (14 +/- 2 to 15 +/- 2 bursts/min) did not significantly change following training. MSNA and cardiovascular responses to exercise and postexercise muscle ischemia were unchanged by training. There were no significant changes in any variables for the sham training and control groups. The results indicate that IHG training is an effective nonpharmacological intervention in lowering arterial pressure.

  12. Arterial baroreflex control of sympathetic nerve activity during acute hypotension: effect of fitness

    NASA Technical Reports Server (NTRS)

    Fadel, P. J.; Stromstad, M.; Hansen, J.; Sander, M.; Horn, K.; Ogoh, S.; Smith, M. L.; Secher, N. H.; Raven, P. B.

    2001-01-01

    We examined arterial baroreflex control of muscle sympathetic nerve activity (MSNA) during abrupt decreases in mean arterial pressure (MAP) and evaluated whether endurance training alters baroreflex function. Acute hypotension was induced nonpharmacologically in 14 healthy subjects, of which 7 were of high fitness (HF) and 7 were of average fitness (AF), by releasing a unilateral arterial thigh cuff after 9 min of resting ischemia under two conditions: control, which used aortic and carotid baroreflex (ABR and CBR, respectively) deactivation; and suction, which used ABR deactivation alone. The application of neck suction to counteract changes in carotid sinus transmural pressure during cuff release significantly attenuated the MSNA response (which increased 134 +/- 32 U/14 s) compared with control (which increased 195 +/- 43 U/14 s) and caused a greater decrease in MAP (19 +/- 2 vs. 15 +/- 2 mmHg; P < 0.05). Furthermore, during both trials, the HF subjects exhibited a greater decrease in MAP compared with AF subjects despite an augmented baroreflex control of MSNA. These data indicate that the CBR contributes importantly to the MSNA response during acute systemic hypotension. Additionally, we suggest that an impaired control of vascular reactivity hinders blood pressure regulation in HF subjects.

  13. Sympathetic activation in exercise is not dependent on muscle acidosis. Direct evidence from studies in metabolic myopathies

    NASA Technical Reports Server (NTRS)

    Vissing, J.; Vissing, S. F.; MacLean, D. A.; Saltin, B.; Quistorff, B.; Haller, R. G.; Blomqvist, C. G. (Principal Investigator)

    1998-01-01

    Muscle acidosis has been implicated as a major determinant of reflex sympathetic activation during exercise. To test this hypothesis we studied sympathetic exercise responses in metabolic myopathies in which muscle acidosis is impaired or augmented during exercise. As an index of reflex sympathetic activation to muscle, microneurographic measurements of muscle sympathetic nerve activity (MSNA) were obtained from the peroneal nerve. MSNA was measured during static handgrip exercise at 30% of maximal voluntary contraction force to exhaustion in patients in whom exercise-induced muscle acidosis is absent (seven myophosphorylase deficient patients; MD [McArdle's disease], and one patient with muscle phosphofructokinase deficiency [PFKD]), augmented (one patient with mitochondrial myopathy [MM]), or normal (five healthy controls). Muscle pH was monitored by 31P-magnetic resonance spectroscopy during handgrip exercise in the five control subjects, four MD patients, and the MM and PFKD patients. With handgrip to exhaustion, the increase in MSNA over baseline (bursts per minute [bpm] and total activity [%]) was not impaired in patients with MD (17+/-2 bpm, 124+/-42%) or PFKD (65 bpm, 307%), and was not enhanced in the MM patient (24 bpm, 131%) compared with controls (17+/-4 bpm, 115+/-17%). Post-handgrip ischemia studied in one McArdle patient, caused sustained elevation of MSNA above basal suggesting a chemoreflex activation of MSNA. Handgrip exercise elicited an enhanced drop in muscle pH of 0.51 U in the MM patient compared with the decrease in controls of 0.13+/-0.02 U. In contrast, muscle pH increased with exercise in MD by 0.12+/-0.05 U and in PFKD by 0.01 U. In conclusion, patients with glycogenolytic, glycolytic, and oxidative phosphorylation defects show normal muscle sympathetic nerve responses to static exercise. These findings indicate that muscle acidosis is not a prerequisite for sympathetic activation in exercise.

  14. Sympathetic support of energy expenditure and sympathetic nervous system activity after gastric bypass surgery

    PubMed Central

    Curry, Timothy B.; Somaraju, Madhuri; Hines, Casey N.; Groenewald, Cornelius B.; Miles, John M.; Joyner, Michael J.; Charkoudian, Nisha

    2012-01-01

    Resting energy expenditure (REE) is partially dependent on the sympathetic nervous system as evidenced by the fact REE decreases during systemic beta-adrenergic blockade. It is not known how gastric bypass affects the sympathetically mediated component of REE or muscle sympathetic nerve activity (MSNA). We measured REE before and after beta-blockade in female subjects approximately three years post-gastric bypass surgery and in female obese individuals for comparison. We also measured MSNA in a subset of these subjects. The gastric bypass subjects had no change in REE after systemic beta-blockade, reflecting a lack of sympathetic support of REE, in contrast to obese subjects where REE was reduced by beta-blockade by approximately 5% (P<0.05). The gastric bypass subjects, while still overweight (BMI = 29.3 vs 38.0 kg/m2 for obese subjects, P<0.05), also had significantly lower MSNA compared to obese subjects (10.9 ± 2.3 vs. 21.9 ± 4.1 bursts/min, P<0.05). The reasons for low MSNA and a lack of sympathetically mediated support of REE after gastric bypass are likely multifactorial and may be related to changes in insulin sensitivity, body composition, and leptin, among other factors. These findings may have important consequences for the maintenance of weight loss after gastric bypass. Longitudinal studies are needed to further explore the changes in sympathetic support of REE and if changes in MSNA or tissue responsiveness are related to the sympathetic support of REE. PMID:23592656

  15. Muscle pain perception and sympathetic nerve activity to exercise during opioid modulation

    NASA Technical Reports Server (NTRS)

    Cook, D. B.; O'Connor, P. J.; Ray, C. A.

    2000-01-01

    The purpose of this experiment was to examine the effects of the endogenous opioid system on forearm muscle pain and muscle sympathetic nerve activity (MSNA) during dynamic fatiguing exercise. Twelve college-age men (24 +/- 4 yr) performed graded (1-min stages; 30 contractions/min) handgrip to fatigue 1 h after the ingestion of either 60 mg codeine, 50 mg naltrexone, or placebo. Pain (0-10 scale) and exertion (0-10 and 6-20 scales) intensities were measured during the last 15 s of each minute of exercise and every 15 s during recovery. MSNA was measured continuously from the peroneal nerve in the left leg. Pain threshold occurred earlier [1.8 +/- 1, 2. 2 +/- 1, 2.2 +/- 1 J: codeine, naltrexone, and placebo, respectively] and was associated with a lower rating of perceived exertion (RPE) (2.7 +/- 2, 3.6 +/- 2, 3.8 +/- 2: codeine, naltrexone, and placebo, respectively) in the codeine condition compared with either the naltrexone or placebo conditions. There were no main effects (i.e., drugs) or interaction (i.e., drugs x time) for either forearm muscle pain or RPE during exercise [pain: F (2, 22) = 0.69, P = 0.51]. There was no effect of drug on MSNA, heart rate, or blood pressure during baseline, exercise, or recovery. Peak exercise MSNA responses were 21 +/- 1, 21 +/- 2.0, and 21 +/- 2.0 bursts/30 s for codeine, naltrexone, and placebo conditions, respectively. Peak mean arterial pressure responses were 135 +/- 4, 131 +/- 3, and 132 +/- 4 mmHg for codeine, naltrexone, and placebo conditions, respectively. It is concluded that neither 60 mg codeine nor 50 mg naltrexone has an effect on forearm muscle pain, exertion, or MSNA during high- intensity handgrip to fatigue.

  16. Bed rest attenuates sympathetic and pressor responses to isometric exercise in antigravity leg muscles in humans.

    PubMed

    Kamiya, Atsunori; Michikami, Daisaku; Shiozawa, Tomoki; Iwase, Satoshi; Hayano, Junichiro; Kawada, Toru; Sunagawa, Kenji; Mano, Tadaaki

    2004-05-01

    Although spaceflight and bed rest are known to cause muscular atrophy in the antigravity muscles of the legs, the changes in sympathetic and cardiovascular responses to exercises using the atrophied muscles remain unknown. We hypothesized that bed rest would augment sympathetic responses to isometric exercise using antigravity leg muscles in humans. Ten healthy male volunteers were subjected to 14-day 6 degrees head-down bed rest. Before and after bed rest, they performed isometric exercises using leg (plantar flexion) and forearm (handgrip) muscles, followed by 2-min postexercise muscle ischemia (PEMI) that continues to stimulate the muscle metaboreflex. These exercises were sustained to fatigue. We measured muscle sympathetic nerve activity (MSNA) in the contralateral resting leg by microneurography. In both pre- and post-bed-rest exercise tests, exercise intensities were set at 30 and 70% of the maximum voluntary force measured before bed rest. Bed rest attenuated the increase in MSNA in response to fatiguing plantar flexion by approximately 70% at both exercise intensities (both P < 0.05 vs. before bed rest) and reduced the maximal voluntary force of plantar flexion by 15%. In contrast, bed rest did not alter the increase in MSNA response to fatiguing handgrip and had no effects on the maximal voluntary force of handgrip. Although PEMI sustained MSNA activation before bed rest in all trials, bed rest entirely eliminated the PEMI-induced increase in MSNA in leg exercises but partially attenuated it in forearm exercises. These results do not support our hypothesis but indicate that bed rest causes a reduction in isometric exercise-induced sympathetic activation in (probably atrophied) antigravity leg muscles.

  17. Sympathetic nerve activity and simulated diving in healthy humans.

    PubMed

    Shamsuzzaman, Abu; Ackerman, Michael J; Kuniyoshi, Fatima Sert; Accurso, Valentina; Davison, Diane; Amin, Raouf S; Somers, Virend K

    2014-04-01

    The goal of our study was to develop a simple and practical method for simulating diving in humans using facial cold exposure and apnea stimuli to measure neural and circulatory responses during the stimulated diving reflex. We hypothesized that responses to simultaneous facial cold exposure and apnea (simulated diving) would be synergistic, exceeding the sum of responses to individual stimuli. We studied 56 volunteers (24 female and 32 male), average age of 39 years. All subjects were healthy, free of cardiovascular and other diseases, and on no medications. Although muscle sympathetic nerve activity (MSNA), blood pressure, and vascular resistance increased markedly during both early and late phases of simulated diving, significant reductions in heart rate were observed only during the late phase. Total MSNA during simulated diving was greater than combined MSNA responses to the individual stimuli. We found that simulated diving is a powerful stimulus to sympathetic nerve traffic with significant bradycardia evident in the late phase of diving and eliciting synergistic sympathetic and parasympathetic responses. Our data provide insight into autonomic triggers that could help explain catastrophic cardiovascular events that may occur during asphyxia or swimming, such as in patients with obstructive sleep apnea or congenital long QT syndrome.

  18. Muscle sympathetic activity in resting and exercising humans with and without heart failure.

    PubMed

    Notarius, Catherine F; Millar, Philip J; Floras, John S

    2015-11-01

    The sympathetic nervous system is critical for coordinating the cardiovascular response to various types of physical exercise. In a number of disease states, including human heart failure with reduced ejection fraction (HFrEF), this regulation can be disturbed and adversely affect outcome. The purpose of this review is to describe sympathetic activity at rest and during exercise in both healthy humans and those with HFrEF and outline factors, which influence these responses. We focus predominately on studies that report direct measurements of efferent sympathetic nerve traffic to skeletal muscle (muscle sympathetic nerve activity; MSNA) using intraneural microneurographic recordings. Differences in MSNA discharge between subjects with and without HFrEF both at rest and during exercise and the influence of exercise training on the sympathetic response to exercise will be discussed. In contrast to healthy controls, MSNA increases during mild to moderate dynamic exercise in the presence of HFrEF. This increase may contribute to the exercise intolerance characteristic of HFrEF by limiting muscle blood flow and may be attenuated by exercise training. Future investigations are needed to clarify the neural afferent mechanisms that contribute to efferent sympathetic activation at rest and during exercise in HFrEF.

  19. Cardiac-locked bursts of muscle sympathetic nerve activity are absent in familial dysautonomia

    PubMed Central

    Macefield, Vaughan G; Norcliffe-Kaufmann, Lucy; Axelrod, Felicia B; Kaufmann, Horacio

    2013-01-01

    Familial dysautonomia (Riley–Day syndrome) is an hereditary sensory and autonomic neuropathy (HSAN type III), expressed at birth, that is associated with reduced pain and temperature sensibilities and absent baroreflexes, causing orthostatic hypotension as well as labile blood pressure that increases markedly during emotional excitement. Given the apparent absence of functional baroreceptor afferents, we tested the hypothesis that the normal cardiac-locked bursts of muscle sympathetic nerve activity (MSNA) are absent in patients with familial dysautonomia. Tungsten microelectrodes were inserted percutaneously into muscle or cutaneous fascicles of the common peroneal nerve in 12 patients with familial dysautonomia. Spontaneous bursts of MSNA were absent in all patients, but in five patients we found evidence of tonically firing sympathetic neurones, with no cardiac rhythmicity, that increased their spontaneous discharge during emotional arousal but not during a manoeuvre that unloads the baroreceptors. Conversely, skin sympathetic nerve activity (SSNA), recorded in four patients, appeared normal. We conclude that the loss of phasic bursts of MSNA and the loss of baroreflex modulation of muscle vasoconstrictor drive contributes to the poor control of blood pressure in familial dysautonomia, and that the increase in tonic firing of muscle vasoconstrictor neurones contributes to the increase in blood pressure during emotional excitement. PMID:23165765

  20. Sympathetic neural activation in nondiabetic metabolic syndrome and its further augmentation by hypertension.

    PubMed

    Huggett, Robert J; Burns, Joanna; Mackintosh, Alan F; Mary, David A S G

    2004-12-01

    Hypertension is a major cardiovascular risk factor in the metabolic syndrome (MS) in which the presence of insulin resistance, glucose intolerance, abnormal lipoprotein metabolism, and central obesity all confer an increased risk. Because essential hypertension (EHT), insulinemia, and visceral fat are associated with sympathetic hyperactivity, which is itself known to increase cardiovascular risk, the aim of this study was to see if MS is a state of sympathetic nerve hyperactivity and if the additional presence of EHT intensifies this hyperactivity. In 69 closely matched subjects, comprising hypertensive MS (MS+EHT, 18), normotensive MS (MS-EHT, 17), hypertensives without MS (EHT, 16), and normotensive controls without MS (NC, 18), we measured resting muscle sympathetic nerve activity (MSNA) as assessed from multiunit discharges and from single units with defined vasoconstrictor properties (s-MSNA). The s-MSNA in MS+EHT (76+/-3.1 impulses/100 beats) was greater (at least P<0.01) than in MS-EHT (62+/-3.2 impulses/100 beats) and in EHT (60+/-2.3 impulses/100 beats), and all these were significantly greater (at least P<0.01) than in NC (46+/-2.7 impulse/100 beats). The multi-unit MSNA followed a similar trend. These findings suggest that MS is a state of sympathetic nerve hyperactivity and that the additional presence of hypertension further intensifies this hyperactivity. The degree of sympathetic hyperactivity seen in this study could be argued at least partly to contribute to the higher cardiovascular risk and metabolic abnormalities seen in MS+EHT patients.

  1. Effects of a T-type calcium channel blocker, ABT-639, on spontaneous activity in C-nociceptors in patients with painful diabetic neuropathy: a randomized controlled trial.

    PubMed

    Serra, Jordi; Duan, W Rachel; Locke, Charles; Solà, Romà; Liu, Wei; Nothaft, Wolfram

    2015-11-01

    T-type calcium channels are a potential novel target for treatment of neuropathic pain such as painful diabetic neuropathy. ABT-639 is a peripherally acting highly selective T-type Ca(v)3.2 calcium channel blocker that has demonstrated analgesic efficacy in preclinical models and may have the potential to reduce spontaneous fiber activity. Microneurography is a unique technique that directly assesses the function of peripheral sensory afferents and measures abnormal spontaneous activity in single peripheral nociceptive C fibers. Abnormal spontaneous activity in C-nociceptors functions as a marker for spontaneous pain, as reduction of this activity could indicate analgesic efficacy. This randomized, double-blind controlled study evaluated the effects of a single 100-mg oral dose of ABT-639, compared with placebo, on abnormal spontaneous activity in peripheral C-nociceptors, measured for the first time by microneurography in adult patients with painful diabetic neuropathy. Lidocaine was included in this study and compared with placebo. Pharmacokinetics and safety of ABT-639 were evaluated. Thirty-nine patients were randomized, and a total of 56 analyzable C-nociceptors with spontaneous activity were identified in 34 patients. There were no significant differences in C-nociceptor activities after ABT-639 treatment vs placebo. Similar findings were observed for lidocaine vs placebo. There were no clinically significant findings in the safety of ABT-639. Further research of T-type Ca(v)3.2 calcium channels as potential treatment targets for painful diabetic neuropathy is warranted. The utilization of microneurography as a means to measure abnormal activity in C-nociceptors in human clinical studies opens new possibilities for future studies of compounds targeting peripheral nerve hyperexcitability. ClinicalTrials.gov identifier: NCT01589432.

  2. Vestibular activation of sympathetic nerve activity

    NASA Technical Reports Server (NTRS)

    Ray, C. A.; Carter, J. R.

    2003-01-01

    AIM: The vestibulosympathetic reflex refers to sympathetic nerve activation by the vestibular system. Animal studies indicate that the vestibular system assists in blood pressure regulation during orthostasis. Although human studies clearly demonstrate activation of muscle sympathetic nerve activity (MSNA) during engagement of the otolith organs, the role of the vestibulosympathetic reflex in maintaining blood pressure during orthostasis is not well-established. Examination of the vestibulosympathetic reflex with other cardiovascular reflexes indicates that it is a powerful and independent reflex. Ageing, which is associated with an increased risk for orthostatic hypotension, attenuates the vestibulosympathetic reflex. The attenuated reflex is associated with a reduction in arterial pressure. CONCLUSION: These findings suggest that the vestibulosympathetic reflex assists in blood pressure regulation in humans, but future studies examining this reflex in other orthostatically intolerant populations are necessary to address this hypothesis.

  3. Effect of pioglitazone on arterial baroreflex sensitivity and sympathetic nerve activity in patients with acute myocardial infarction and type 2 diabetes mellitus.

    PubMed

    Yokoe, Hiroshi; Yuasa, Fumio; Yuyama, Reisuke; Murakawa, Kousuke; Miyasaka, Yoko; Yoshida, Susumu; Tsujimoto, Satoshi; Sugiura, Tetsuro; Iwasaka, Toshiji

    2012-06-01

    Pioglitazone has been shown to reduce the occurrence of fatal and nonfatal myocardial infarction (MI) in type 2 diabetes mellitus (DM). However, the mechanisms of such favorable effects remain speculative. The aim of this study was to investigate the effect of pioglitazone on arterial baroreflex sensitivity (BRS) and muscle sympathetic nerve activity (MSNA) in 30 DM patients with recent MI. Patients were randomly assigned to those taking pioglitazone (n = 15) and those not taking pioglitazone (n = 15) at 4 weeks after the onset of MI. BRS, MSNA, calculated homeostasis model assessment of insulin resistance index (HOMA-IR), and plasma adiponectin were measured at baseline and after 12 weeks. Pioglitazone increased plasma adiponectin (from 6.9 ± 3.3 μg/dL to 12.2 ± 7.1 μg/dL) and reduced HOMA-IR (from 4.0 ± 2.2 to 2.1 ± 0.9). In the pioglitazone group, MSNA decreased significantly (from 37 ± 7 bursts/min to 25 ± 8 bursts/min) and BRS increased significantly (from 6.7 ± 3.0 to 9.9 ± 3.2 ms/mm Hg) after 12 weeks. Furthermore, a significant relationship was found between the change in MSNA and HOMA-IR (r = 0.6, P = 0.042). Thus, pioglitazone decreased the sympathetic nerve traffic through the improvement of insulin resistance in DM patients with recent MI, which indicate that the sympathoinhibitory effects of pioglitazone may, at least in part, have contributed to the beneficial effects of pioglitazone.

  4. Neurovascular control during exercise in acute coronary syndrome patients with Gln27Glu polymorphism of β2-adrenergic receptor

    PubMed Central

    Ferreira-Santos, Larissa; Martinez, Daniel G.; Nicolau, José Carlos; Moreira, Humberto G.; Alves, Maria Janieire; Pereira, Alexandre C.; Trombetta, Ivani C.; Negrão, Carlos Eduardo

    2017-01-01

    Background Gln27Glu (rs1042714) polymorphism of the β2-adrenergic receptor (ADRB2) has been association with cardiovascular functionality in healthy subjects. However, it is unknown whether the presence of the ADRB2 Gln27Glu polymorphism influences neurovascular responses during exercise in patients with acute coronary syndromes (ACS). We tested the hypothesis that patients with ACS homozygous for the Gln allele would have increased muscle sympathetic nerve activity (MSNA) responses and decreased forearm vascular conductance (FVC) responses during exercise compared with patients carrying the Glu allele (Gln27Glu and Glu27Glu). In addition, exercise training would restore these responses in Gln27Gln patients. Methods and results Thirty-days after an ischemic event, 61 patients with ACS without ventricular dysfunction were divided into 2 groups: (1) Gln27Gln (n = 35, 53±1years) and (2) Gln27Glu+Glu27Glu (n = 26, 52±2years). MSNA was directly measured using the microneurography technique, blood pressure (BP) was measured with an automatic oscillometric device, and blood flow was measured using venous occlusion plethysmography. MSNA, mean BP, and FVC were evaluated at rest and during a 3-min handgrip exercise. The MSNA (P = 0.02) and mean BP (P = 0.04) responses during exercise were higher in the Gln27Gln patients compared with that in the Gln27Glu+Glu27Glu patients. No differences were found in FVC. Two months of exercise training significantly decreased the MSNA levels at baseline (P = 0.001) and in their response during exercise (P = 0.02) in Gln27Gln patients, but caused no changes in Gln27Glu+Glu27Glu patients. Exercise training increased FVC responses in Gln27Glu+Glu27Glu patients (P = 0.03), but not in Gln27Gln patients. Conclusion The exaggerated MSNA and mean BP responses during exercise suggest an increased cardiovascular risk in patients with ACS and Gln27Gln polymorphism. Exercise training emerges as an important strategy for restoring this reflex

  5. α-Adrenergic effects on low-frequency oscillations in blood pressure and R-R intervals during sympathetic activation.

    PubMed

    Kiviniemi, Antti M; Frances, Maria F; Tiinanen, Suvi; Craen, Rosemary; Rachinsky, Maxim; Petrella, Robert J; Seppänen, Tapio; Huikuri, Heikki V; Tulppo, Mikko P; Shoemaker, J Kevin

    2011-08-01

    The present study was designed to address the contribution of α-adrenergic modulation to the genesis of low-frequency (LF; 0.04-0.15 Hz) oscillations in R-R interval (RRi), blood pressure (BP) and muscle sympathetic nerve activity (MSNA) during different sympathetic stimuli. Blood pressure and RRi were measured continuously in 12 healthy subjects during 5 min periods each of lower body negative pressure (LBNP; -40 mmHg), static handgrip exercise (HG; 20% of maximal force) and postexercise forearm circulatory occlusion (PECO) with and without α-adrenergic blockade by phentolamine. Muscle sympathetic nerve activity was recorded in five subjects during LBNP and in six subjects during HG and PECO. Low-frequency powers and median frequencies of BP, RRi and MSNA were calculated from power spectra. Low-frequency power during LBNP was lower with phentolamine versus without for both BP and RRi oscillations (1.6 ± 0.6 versus 1.2 ± 0.7 ln mmHg(2), P = 0.049; and 6.9 ± 0.8 versus 5.4 ± 0.9 ln ms(2), P = 0.001, respectively). In contrast, the LBNP with phentolamine increased the power of high-frequency oscillations (0.15-0.4 Hz) in BP and MSNA (P < 0.01 for both), which was not observed during saline infusion. Phentolamine also blunted the increases in the LBNP-induced increase in frequency of LF oscillations in BP and RRi. Phentolamine decreased the LF power of RRi during HG (P = 0.015) but induced no other changes in LF powers or frequencies during HG. Phentolamine resulted in decreased frequency of LF oscillations in RRi (P = 0.004) during PECO, and a similar tendency was observed in BP and MSNA. The power of LF oscillation in MSNA did not change during any intervention. We conclude that α-adrenergic modulation contributes to LF oscillations in BP and RRi during baroreceptor unloading (LBNP) but not during static exercise. Also, α-adrenergic modulation partly explains the shift to a higher frequency of LF oscillations during baroreceptor unloading and muscle

  6. Functional and structural changes in the brain associated with the increase in muscle sympathetic nerve activity in obstructive sleep apnoea.

    PubMed

    Fatouleh, Rania H; Hammam, Elie; Lundblad, Linda C; Macey, Paul M; McKenzie, David K; Henderson, Luke A; Macefield, Vaughan G

    2014-01-01

    Muscle sympathetic nerve activity (MSNA) is greatly elevated in patients with obstructive sleep apnoea (OSA) during daytime wakefulness, leading to hypertension, but the underlying mechanisms are poorly understood. By recording MSNA concurrently with functional Magnetic Resonance Imaging (fMRI) of the brain we aimed to identify the central processes responsible for the sympathoexcitation. Spontaneous fluctuations in MSNA were recorded via tungsten microelectrodes inserted percutaneously into the common peroneal nerve in 17 OSA patients and 15 healthy controls lying in a 3 T MRI scanner. Blood Oxygen Level Dependent (BOLD) contrast gradient echo, echo-planar images were continuously collected in a 4 s ON, 4 s OFF (200 volumes) sampling protocol. Fluctuations in BOLD signal intensity covaried with the intensity of the concurrently recorded bursts of MSNA. In both groups there was a positive correlation between MSNA and signal intensity in the left and right insulae, dorsolateral prefrontal cortex (dlPFC), dorsal precuneus, sensorimotor cortex and posterior temporal cortex, and the right mid-cingulate cortex and hypothalamus. In OSA the left and right dlPFC, medial PFC (mPFC), dorsal precuneus, anterior cingulate cortex, retrosplenial cortex and caudate nucleus showed augmented signal changes compared with controls, while the right hippocampus/parahippocampus signal intensity decreased in controls but did not change in the OSA subjects. In addition, there were significant increases in grey matter volume in the left mid-insula, the right insula, left and right primary motor cortices, left premotor cortex, left hippocampus and within the brainstem and cerebellum, and significant decreases in the mPFC, occipital lobe, right posterior cingulate cortex, left cerebellar cortex and the left and right amygdala in OSA, but there was no overlap between these structural changes and the functional changes in OSA. These data suggest that the elevated muscle vasoconstrictor drive

  7. Role of sympathetic nerve activity in the process of fainting

    PubMed Central

    Iwase, Satoshi; Nishimura, Naoki; Mano, Tadaaki

    2014-01-01

    Syncope is defined as a transient loss of consciousness and postural tone, characterized by rapid onset, short duration, and spontaneous recovery, and the process of syncope progression is here described with two types of sympathetic change. Simultaneous recordings of microneurographically-recorded muscle sympathetic nerve activity (MSNA) and continuous and noninvasive blood pressure measurement has disclosed what is going on during the course of syncope progression. For vasovagal or neurally mediated syncope, three stages are identified in the course of syncope onset, oscillation, imbalance, and catastrophe phases. Vasovagal syncope is characterized by sympathoexcitation, followed by vagal overcoming via the Bezold-Jarisch reflex. Orthostatic syncope is caused by response failure or a lack of sympathetic nerve activity to the orthostatic challenge, followed by fluid shift and subsequent low cerebral perfusion. Four causes are considered for the compensatory failure that triggers orthostatic syncope: hypovolemia, increased pooling in the lower body, failure to activate sympathetic activity, and failure of vasoconstriction against sympathetic vasoconstrictive stimulation. Many pathophysiological conditions have been described from the perspectives of (1) exaggerated sympathoexcitation and (2) failure to activate the sympathetic nerve. We conclude that the sympathetic nervous system can control cardiovascular function, and its failure results in syncope; however, responses of the system obtained by microneurographically-recorded MSNA would determine the pathophysiology of the onset and progression of syncope, explaining the treatment effect that could be achieved by the analysis of this mechanism. PMID:25309444

  8. Differential responses to CO2 and sympathetic stimulation in the cerebral and femoral circulations in humans

    PubMed Central

    Ainslie, Philip N; Ashmead, Jon C; Ide, Kojiro; Morgan, Barbara J; Poulin, Marc J

    2005-01-01

    The relative importance of CO2 and sympathetic stimulation in the regulation of cerebral and peripheral vasculatures has not been previously studied in humans. We investigated the effect of sympathetic activation, produced by isometric handgrip (HG) exercise, on cerebral and femoral vasculatures during periods of isocapnia and hypercapnia. In 14 healthy males (28.1 ± 3.7 (mean ± s.d.) years), we measured flow velocity (; transcranial Doppler ultrasound) in the middle cerebral artery during euoxic isocapnia (ISO, +1 mmHg above rest) and two levels of euoxic hypercapnia (HC5, end-tidal PCO2, PET,CO2, = +5 mmHg above ISO; HC10, PET,CO2= +10 above ISO). Each PET,CO2 level was maintained for 10 min using the dynamic end-tidal forcing technique, during which increases in sympathetic activity were elicited by a 2-min HG at 30% of maximal voluntary contraction. Femoral blood flow (FBF; Doppler ultrasound), muscle sympathetic nerve activity (MSNA; microneurography) and mean arterial pressure (MAP; Portapres) were also measured. Hypercapnia increased and FBF by 5.0 and 0.6% mmHg−1, respectively, and MSNA by 20–220%. Isometric HG increased MSNA by 50% and MAP by 20%, with no differences between ISO, HC5 and HC10. During the ISO HG there was an increase in cerebral vascular resistance (CVR; 20 ± 11%), while remained unchanged. During HC5 and HC10 HG, increased (13% and 14%, respectively), but CVR was unchanged. In contrast, HG-induced sympathetic stimulation increased femoral vascular resistance (FVR) during ISO, HC5 and HC10 (17–41%), while there was a general decrease in FBF below ISO. The HG-induced increases in MSNA were associated with increases in FVR in all conditions (r = 0.76–0.87), whereas increases in MSNA were associated with increases in CVR only during ISO (r = 0.91). In summary, in the absence of hypercapnia, HG exercise caused cerebral vasoconstriction, myogenically and/or neurally, which was reflected by increases in CVR and a maintained . In

  9. Increased sympathetic nerve activity and reduced cardiac baroreflex sensitivity in rheumatoid arthritis

    PubMed Central

    Adlan, Ahmed M.; Paton, Julian F. R.; Lip, Gregory Y. H.; Kitas, George D.

    2016-01-01

    Key points Rheumatoid arthritis (RA) is a chronic inflammatory condition associated with an increased risk of cardiovascular mortality.Increased sympathetic nerve activity and reduced cardiac baroreflex sensitivity heighten cardiovascular risk, althogh whether such autonomic dysfunction is present in RA is not known.In the present study, we observed an increased sympathetic nerve activity and reduced cardiac baroreflex sensitivity in patients with RA compared to matched controls.Pain was positively correlated with sympathetic nerve activity and negatively correlated with cardiac baroreflex sensitivity.The pattern of autonomic dysfunction that we describe may help to explain the increased cardiovascular risk in RA, and raises the possibility that optimizing pain management may resolve autonomic dysfunction in RA. Abstract Rheumatoid arthritis (RA) is a chronic inflammatory condition associated with increased cardiovascular morbidity/mortality and an incompletely understood pathophysiology. In animal studies, central and blood borne inflammatory cytokines that can be elevated in RA evoke pathogenic increases in sympathetic activity and reductions in baroreflex sensitivity (BRS). We hypothesized that muscle sympathetic nerve activity (MSNA) was increased and BRS decreased in RA. MSNA, blood pressure and heart rate (HR) were recorded in age‐ and sex‐matched RA‐normotensive (n = 13), RA‐hypertensive patients (RA‐HTN; n = 17), normotensive (NC; n = 17) and hypertensive controls (HTN; n = 16). BRS was determined using the modified Oxford technique. Inflammation and pain were determined using serum high sensitivity C‐reactive protein (hs‐CRP) and a visual analogue scale (VAS), respectively. MSNA was elevated similarly in RA, RA‐HTN and HTN patients (32 ± 9, 35 ± 14, 37 ± 8 bursts min–1) compared to NC (22 ± 9 bursts min–1; P = 0.004). Sympathetic BRS was similar between groups (P = 0.927), whereas cardiac BRS (cBRS) was

  10. Obstructive Sleep Apnea Impairs Postexercise Sympathovagal Balance in Patients with Metabolic Syndrome

    PubMed Central

    Cepeda, Felipe X.; Toschi-Dias, Edgar; Maki-Nunes, Cristiane; Rondon, Maria Urbana P.B.; Alves, Maria Janieire N.N.; Braga, Ana Maria F.W.; Martinez, Daniel G.; Drager, Luciano F.; Lorenzi-Filho, Geraldo; Negrao, Carlos E.; Trombetta, Ivani C.

    2015-01-01

    Study Objectives: The attenuation of heart rate recovery after maximal exercise (ΔHRR) is independently impaired by obstructive sleep apnea (OSA) and metabolic syndrome (MetS). Therefore, we tested the hypotheses: (1) MetS + OSA restrains ΔHRR; and (2) Sympathetic hyperactivation is involved in this impairment. Design: Cross-sectional study. Participants: We studied 60 outpatients in whom MetS had been newly diagnosed (ATP III), divided according to apnea-hypopnea index (AHI) ≥ 15 events/h in MetS + OSA (n = 30, 49 ± 1.7 y) and AHI < 15 events/h in MetS - OSA (n = 30, 46 ± 1.4 y). Normal age-matched healthy control subjects (C) without MetS and OSA were also enrolled (n = 16, 46 ± 1.7 y). Interventions: Polysomnography, microneurography, cardiopulmonary exercise test. Measurements and Results: We evaluated OSA (AHI - polysomnography), muscle sympathetic nerve activity (MSNA - microneurography) and cardiac autonomic activity (LF = low frequency, HF = high frequency, LF/HF = sympathovagal balance) based on spectral analysis of heart rate (HR) variability. ΔHRR was calculated (peak HR minus HR at first, second, and fourth minute of recovery) after cardiopulmonary exercise test. MetS + OSA had higher MSNA and LF, and lower HF than MetS - OSA and C. Similar impairment occurred in MetS - OSA versus C (interaction, P < 0.01). MetS + OSA had attenuated ΔHRR at first, second, and at fourth minute than did C, and attenuated ΔHRR at fourth minute than did MetS - OSA (interaction, P < 0.001). Compared with C, MetS - OSA had attenuated ΔHRR at second and fourth min (interaction, P < 0.001). Further analysis showed association of the ΔHRR (first, second, and fourth minute) and AHI, MSNA, LF and HF components (P < 0.05 for all associations). Conclusions: The attenuation of heart rate recovery after maximal exercise is impaired to a greater degree where metabolic syndrome (MetS) is associated with moderate to severe obstructive sleep apnea (OSA) than by MetS with no or

  11. The influence of aetiology on the benefits of exercise training in patients with heart failure.

    PubMed

    Antunes-Correa, Ligia M; Ueno-Pardi, Linda M; Trevizan, Patricia F; Santos, Marcelo R; da Silva, Carlos Henrique P; Franco, Fábio Gm; Alves, Maria Janieire Nn; Rondon, Maria Urbana Pb; Negrao, Carlos E

    2017-03-01

    Background Exercise training improves neurovascular control and functional capacity in heart failure (HF) patients. However, the influence of the aetiology on these benefits is unknown. We compared the effects of exercise training on neurovascular control and functional capacity in idiopathic, ischaemic and hypertensive HF patients. Design Subjects consisted of 45 exercise-trained HF patients from our database (2000-2015), aged 40-70 years old, functional class II/III and ejection fraction ≤40%, and they were divided into three groups: idiopathic ( n = 11), ischaemic ( n = 18) and hypertensive ( n = 16). Methods Functional capacity was determined by cardiopulmonary exercise testing. Muscle sympathetic nerve activity (MSNA) was recorded by microneurography. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. Results Four months of exercise training significantly reduced MSNA and significantly increased FBF in all groups. However, the relative reduction in MSNA was greater in hypertensive patients compared with that in idiopathic patients (frequency: -34% vs . -15%, p = 0.01; incidence: -31% vs . -12%, p = 0.02). No differences were found between hypertensive patients and ischaemic patients. The relative increase in FBF was greater in hypertensive patients than in ischaemic and idiopathic patients (42% vs. 15% and 17%, respectively, p = 0.02). The relative increase in forearm vascular conductance was greater in hypertensive patients compared with those in ischaemic and idiopathic patients (57% vs . 13% and 26%, respectively, p = 0.001). Exercise training significantly and similarly increased peak oxygen consumption in all groups. Conclusion The exercise-induced improvement in neurovascular control is more pronounced in hypertensive HF patients than in idiopathic and ischaemic HF patients. The increase in functional capacity is independent of aetiology.

  12. Effect of morphine on sympathetic nerve activity in humans

    NASA Technical Reports Server (NTRS)

    Carter, Jason R.; Sauder, Charity L.; Ray, Chester A.

    2002-01-01

    There are conflicting reports for the role of endogenous opioids on sympathetic and cardiovascular responses to exercise in humans. A number of studies have utilized naloxone (an opioid-receptor antagonist) to investigate the effect of opioids during exercise. In the present study, we examined the effect of morphine (an opioid-receptor agonist) on sympathetic and cardiovascular responses at rest and during isometric handgrip (IHG). Eleven subjects performed 2 min of IHG (30% maximum) followed by 2 min of postexercise muscle ischemia (PEMI) before and after systemic infusion of morphine (0.075 mg/kg loading dose + 1 mg/h maintenance) or placebo (saline) in double-blinded experiments on separate days. Morphine increased resting muscle sympathetic nerve activity (MSNA; 17 +/- 2 to 22 +/- 2 bursts/min; P < 0.01) and increased mean arterial pressure (MAP; 87 +/- 2 to 91 +/- 2 mmHg; P < 0.02), but it decreased heart rate (HR; 61 +/- 4 to 59 +/- 3; P < 0.01). However, IHG elicited similar increases for MSNA, MAP, and HR between the control and morphine trial (drug x exercise interaction = not significant). Moreover, responses to PEMI were not different. Placebo had no effect on resting, IHG, and PEMI responses. We conclude that morphine modulates cardiovascular and sympathetic responses at rest but not during isometric exercise.

  13. Magnetic stimulation of the human motor cortex evokes skin sympathetic nerve activity.

    PubMed

    Silber, D H; Sinoway, L I; Leuenberger, U A; Amassian, V E

    2000-01-01

    Single-pulse magnetic coil stimulation (Cadwell MES 10) over the cranium induces without pain an electric pulse in the underlying cerebral cortex. Stimulation over the motor cortex can elicit a muscle twitch. In 10 subjects, we tested whether motor cortical stimulation could also elicit skin sympathetic nerve activity (SSNA; n = 8) and muscle sympathetic nerve activity (MSNA; n = 5) in the peroneal nerve. Focal motor cortical stimulation predictably elicited bursts of SSNA but not MSNA; with successive stimuli, the SSNA responses did not readily extinguish (94% of discharges to the motor cortex evoked SSNA responses) and had predictable latencies [739 +/- 33 (SE) to 895 +/- 13 ms]. The SSNA responses were similar after stimulation of dominant and nondominant sides. Focal stimulation posterior to the motor cortex elicited extinguishable SSNA responses. In three of six subjects, anterior cortical stimulation evoked SSNA responses similar to those seen with motor cortex stimulation but without detectable movement; in the other subjects, anterior stimulation evoked less SSNA discharge than that seen with motor cortex stimulation. Contrasting with motor cortical stimulation, evoked SSNA responses were more readily extinguished with 1) peripheral stimulation that directly elicited forearm muscle activation accompanied by electromyograms similar to those with motor cortical stimulation; 2) auditory stimulation by the click of the energized coil when off the head; and 3) in preliminary experiments, finger afferent stimulation sufficient to cause tingling. Our findings are consistent with the hypothesis that motor cortex stimulation can cause activation of both alpha-motoneurons and SSNA.

  14. Anxiolytic therapy with alprazolam increases muscle sympathetic activity in patients with panic disorders.

    PubMed

    Béchir, Markus; Schwegler, Kyrill; Chenevard, Rémy; Binggeli, Christian; Caduff, Christian; Büchi, Stefan; Buddeberg, Claus; Lüscher, Thomas F; Noll, Georg

    2007-07-31

    Anxiolytic therapy with the benzodiazepine alprazolam is an established therapy in patients with panic disorder. Normally, panic-like anxiety and its concomitant physical symptoms quickly disappear under such treatment. Therefore we investigated whether there is a difference in sympathetic nervous system in patients with panic disorder compared to healthy controls. Three groups of subjects were included: ten patients with panic disorder, who received alprazolam and 20 healthy control subjects who were given either alprazolam (n=10) or matching placebo (n=10). Muscle sympathetic nerve activity (MSNA) and heart rate did not differ at baseline but significantly increased both in patients and healthy controls after intake of alprazolam (1 mg). However, in both groups both MSNA and heart rate were significantly elevated when compared to both baseline and the placebo control group. This study demonstrates (1) that anxiolytic therapy with alprazolam increases muscle sympathetic nerve activity and heart rate not only in patients with panic disorder but also in healthy controls and (2) that a significant difference in sympathetic nervous system activity between patients and controls, at baseline and during the therapy with alprazolam could not be demonstrated.

  15. Opposing effects of shear-mediated dilation and myogenic constriction on artery diameter in response to handgrip exercise in humans.

    PubMed

    Atkinson, Ceri L; Carter, Howard H; Naylor, Louise H; Dawson, Ellen A; Marusic, Petra; Hering, Dagmara; Schlaich, Markus P; Thijssen, Dick H J; Green, Daniel J

    2015-10-15

    While the impact of changes in blood flow and shear stress on artery function are well documented, the acute effects of increases in arterial pressure are less well described in humans. The aim of this study was to assess the effect of 30 min of elevated blood pressure, in the absence of changes in shear stress or sympathetic nervous system (SNS) activation, on conduit artery diameter. Ten healthy male subjects undertook three sessions of 30 min unilateral handgrip exercise at 5, 10, and 15% of maximal voluntary contractile (MVC) strength. Brachial artery shear rate and blood flow profiles were measured simultaneously during exercise in the active and contralateral resting arms. Bilateral brachial artery diameter was simultaneously assessed before and immediately postexercise. In a second experiment, six subjects repeated the 15% MVC condition while continuous vascular measurements were collected during muscle sympathetic nerve activity (MSNA) assessment using peroneal microneurography. We found that unilateral handgrip exercise at 5, 10, and 15% MVC strength induced stepwise elevations in blood pressure (P < 0.01, Δmean arterial pressure: 7.06 ± 2.44, 8.50 ± 2.80, and 18.35 ± 3.52 mmHg, P < 0.01). Whereas stepwise increases were evident in shear rate in the exercising arm (P < 0.001), no changes were apparent in the nonexercising limb (P = 0.42). Brachial artery diameter increased in the exercising arm (P = 0.02), but significantly decreased in the nonexercising arm (P = 0.03). At 15% MVC, changes in diameter were significantly different between arms (interaction effect: P = 0.01), whereas this level of exertion produced no significant changes in MSNA. We conclude that acute increases in transmural pressure, independent of shear rate and changes in SNS activation, reduce arterial caliber in normotensive humans in vivo. These changes in diameter were mitigated by exercise-induced elevations in shear rate in the active limb.

  16. Symptoms of anxiety and mood disturbance alter cardiac and peripheral autonomic control in patients with metabolic syndrome.

    PubMed

    Toschi-Dias, Edgar; Trombetta, Ivani C; da Silva, Valdo José Dias; Maki-Nunes, Cristiane; Alves, Maria Janieire N N; Angelo, Luciana F; Cepeda, Felipe X; Martinez, Daniel G; Negrão, Carlos Eduardo; Rondon, Maria Urbana P B

    2013-03-01

    Previous investigations show that metabolic syndrome (MetSyn) causes sympathetic hyperactivation. Symptoms of anxiety and mood disturbance (AMd) provoke sympatho-vagal imbalance. We hypothesized that AMd would alter even further the autonomic function in patients with MetSyn. Twenty-six never-treated patients with MetSyn (ATP-III) were allocated to two groups, according to the levels of anxiety and mood disturbance: (1) with AMd (MetSyn + AMd, n = 15), and (2) without AMd (MetSyn, n = 11). Ten healthy control subjects were also studied (C, n = 10). AMd was determined using quantitative questionnaires. Muscle sympathetic nerve activity (MSNA, microneurography), blood pressure (oscillometric beat-to-beat basis), and heart rate (ECG) were measured during a baseline 10-min period. Spectral analysis of RR interval and systolic arterial pressure were analyzed, and the power of low (LF) and high (HF) frequency bands were determined. Sympatho-vagal balance was obtained by LF/HF ratio. Spontaneous baroreflex sensitivity (BRS) was evaluated by calculation of α-index. MSNA was greater in patients with MetSyn + AMd compared with MetSyn and C. Patients with MetSyn + AMd showed higher LF and lower HF power compared with MetSyn and C. In addition, LF/HF balance was higher in MetSyn + AMd than in MetSyn and C groups. BRS was decreased in MetSyn + AMd compared with MetSyn and C groups. Anxiety and mood disturbance alter autonomic function in patients with MetSyn. This autonomic dysfunction may contribute to the increased cardiovascular risk observed in patients with mood alterations.

  17. Cutaneous Mechanoreceptor Feedback from the Hand and Foot Can Modulate Muscle Sympathetic Nerve Activity

    PubMed Central

    Strzalkowski, Nicholas D. J.; Incognito, Anthony V.; Bent, Leah R.; Millar, Philip J.

    2016-01-01

    Stimulation of high threshold mechanical nociceptors on the skin can modulate efferent sympathetic outflow. Whether low threshold mechanoreceptors from glabrous skin are similarly capable of modulating autonomic outflow is unclear. Therefore, the purpose of this study was to examine the effects of cutaneous afferent feedback from the hand palm and foot sole on efferent muscle sympathetic nerve activity (MSNA). Fifteen healthy young participants (9 male; 25 ± 3 years [range: 22–29]) underwent microneurographic recording of multi-unit MSNA from the right fibular nerve during 2 min of baseline and 2 min of mechanical vibration (150 Hz, 220 μm peak-to-peak) applied to the left hand or foot. Each participant completed three trials of both hand and foot stimulation, each separated by 5 min. MSNA burst frequency decreased similarly during the 2 min of both hand (20.8 ± 8.9 vs. 19.3 ± 8.6 bursts/minute [Δ −8%], p = 0.035) and foot (21.0 ± 8.3 vs. 19.5 ± 8.3 bursts/minute [Δ −8%], p = 0.048) vibration but did not alter normalized mean burst amplitude or area (All p > 0.05). Larger reductions in burst frequency were observed during the first 10 s (onset) of both hand (20.8 ± 8.9 vs. 17.0 ± 10.4 [Δ −25%], p < 0.001) and foot (21.0 ± 8.3 vs. 18.3 ± 9.4 [Δ −16%], p = 0.035) vibration, in parallel with decreases in normalized mean burst amplitude (hand: 0.45 ± 0.06 vs. 0.36 ± 0.14% [Δ −19%], p = 0.03; foot: 0.47 ± 0.07 vs. 0.34 ± 0.19% [Δ −27%], p = 0.02) and normalized mean burst area (hand: 0.42 ± 0.05 vs. 0.32 ± 0.12% [Δ −25%], p = 0.003; foot: 0.47 ± 0.05 vs. 0.34 ± 0.16% [Δ −28%], p = 0.01). These results demonstrate that tactile feedback from the hands and feet can influence efferent sympathetic outflow to skeletal muscle. PMID:28008306

  18. The persistence of the NWA effect during the low solar activity period 2007-2009

    NASA Astrophysics Data System (ADS)

    Jakowski, N.; Hoque, M. M.; Kriegel, M.; Patidar, V.

    2015-10-01

    The ionospheric Nighttime Winter Anomaly (NWA) was first reported more than three decades ago based on total electron content (TEC) and vertical sounding data. The aim of this paper is to provide further evidence that the NWA effect is a persistent feature in the Northern Hemisphere at the American and in the Southern Hemisphere at the Asian longitude sector under low solar activity conditions. The analysis of ground-based GPS derived TEC and peak electron density data from radio occultation measurements on Formosat-3/COSMIC satellites confirms and further supports the findings published in earlier NWA papers. So it has been confirmed and further specified that the NWA appears at longitude sectors where the displacement between the geomagnetic and the geographic equator maximizes. Here NWA peaks at around 40°-50° geomagnetic midlatitude supporting the idea that wind-induced plasma uplifting in the conjugated summer hemisphere is the main driving force for the accumulation of ionospheric plasma in the topside ionosphere and plasmasphere. In parallel, the midsummer nighttime anomaly (MSNA) is caused at the local ionosphere. Simultaneously, interhemispheric coupling causes severe downward plasma fluxes in the conjugated winter hemisphere during night causing the NWA at low solar activity. With increasing solar activity, the downward plasma fluxes lose their impact due to the much stronger increasing background ionization that masks the NWA. It is assumed that MSNA and related special anomalies such as the Weddell Sea Anomaly and the Okhotsk Sea Anomaly are closely related to the NWA via enhanced wind-induced uplifting of the ionosphere.

  19. Asian women have attenuated sympathetic activation but enhanced renal–adrenal responses during pregnancy compared to Caucasian women

    PubMed Central

    Okada, Yoshiyuki; Best, Stuart A; Jarvis, Sara S; Shibata, Shigeki; Parker, Rosemary S; Casey, Brian M; Levine, Benjamin D; Fu, Qi

    2015-01-01

    Abstract Asians have a lower prevalence of hypertensive disorders of pregnancy than Caucasians. Since sympathetic overactivity and dysregulation of the renal–adrenal system (e.g. low aldosterone levels) have been found in preeclamptic women, we hypothesized that Asians have lower muscle sympathetic nerve activity (MSNA) and greater aldosterone concentrations during normal pregnancy than Caucasians. In a prospective study, blood pressure (BP), heart rate (HR), and MSNA were measured during supine and upright tilt (30 deg and 60 deg for 5 min each) in 9 Asians (32 ± 1 years (mean ± SEM)) and 12 Caucasians (29 ± 1 years) during pre-, early (≤8 weeks of gestation) and late (32–36 weeks) pregnancy, and post-partum (6–10 weeks after delivery). Supine MSNA increased with pregnancy in both groups (P < 0.001); it was significantly lower in Asians than Caucasians (14 ± 3 vs. 23 ± 3 bursts min−1 and 16 ± 5 vs. 30 ± 3 bursts min−1 in early and late pregnancy, respectively; P = 0.023). BP decreased during early pregnancy (P < 0.001), but was restored during late pregnancy. HR increased during pregnancy (P < 0.001) with no racial difference (P = 0.758). MSNA increased during tilting and it was markedly lower in Asians than Caucasians in late pregnancy (31 ± 6 vs. 49 ± 3 bursts min−1 at 60 deg tilt; P = 0.003). Upright BP was lower in Asians, even in pre-pregnancy (P = 0.006), and this racial difference persisted during pregnancy. Direct renin and aldosterone increased during pregnancy (both P < 0.001); these hormones were greater in Asians (P = 0.086 and P = 0.014). Thus, Asians have less sympathetic activation but more upregulated renal–adrenal responses than Caucasians during pregnancy. These results may explain, at least in part, why Asian women are at low risk of hypertensive disorders in pregnancy. Key points Asian women have a lower prevalence of hypertensive disorders of pregnancy than Caucasian

  20. Human muscle spindle sensitivity reflects the balance of activity between antagonistic muscles.

    PubMed

    Dimitriou, Michael

    2014-10-08

    Muscle spindles are commonly considered as stretch receptors encoding movement, but the functional consequence of their efferent control has remained unclear. The "α-γ coactivation" hypothesis states that activity in a muscle is positively related to the output of its spindle afferents. However, in addition to the above, possible reciprocal inhibition of spindle controllers entails a negative relationship between contractile activity in one muscle and spindle afferent output from its antagonist. By recording spindle afferent responses from alert humans using microneurography, I show that spindle output does reflect antagonistic muscle balance. Specifically, regardless of identical kinematic profiles across active finger movements, stretch of the loaded antagonist muscle (i.e., extensor) was accompanied by increased afferent firing rates from this muscle compared with the baseline case of no constant external load. In contrast, spindle firing rates from the stretching antagonist were lowest when the agonist muscle powering movement (i.e., flexor) acted against an additional resistive load. Stepwise regressions confirmed that instantaneous velocity, extensor, and flexor muscle activity had a significant effect on spindle afferent responses, with flexor activity having a negative effect. Therefore, the results indicate that, as consequence of their efferent control, spindle sensitivity (gain) to muscle stretch reflects the balance of activity between antagonistic muscles rather than only the activity of the spindle-bearing muscle.

  1. Impact of lung inflation cycle frequency on rat muscle and skin sympathetic activity recorded using suction electrodes

    PubMed Central

    Huang, Chunhua; Marina, Nephtali; Gilbey, Michael P.

    2009-01-01

    Microneurography has been used in humans to study sympathetic activity supplying targets within skeletal muscle and skin. Comparable animal studies are relatively few, probably due to the technical demands of traditional fibre picking techniques. Here we apply a simple suction electrode technique to record cutaneous (CVC) and muscle (MVC) vasoconstrictor activities and describe and investigate the basis of the frequency dependence of lung inflation related modulation. Hindlimb MVC and CVC activities were recorded concurrently. The magnitude of MVC and CVC activities at the lung inflation cycle frequency was significantly less at 2.0 Hz than at lung inflation cycle frequencies ≤ 1.0 Hz. As lung inflation cycle frequency was increased the coherence between lung inflation cycle or BP and MVC or CVC waveforms decreased. Consistent with the hypothesis that much of the coherence between lung inflation cycle and nerve activity waveforms is secondary to oscillating baroreceptor activity attributable to BP waves, partialization with the BP waveform significantly decreased the coherence between lung inflation cycle and nerve waveforms, and there was an absence of coherence between these waveforms following sinus and aortic denervation. Our data extend findings from other laboratories and establish the value of a suction electrode technique for recording MVC and CVC activities. Furthermore, our observations describe the rates of positive pressure ventilation that avoid strong and regular gating of sympathetic activity. PMID:19457723

  2. SCN10A Mutation in a Patient with Erythromelalgia Enhances C-Fiber Activity Dependent Slowing

    PubMed Central

    Neacsu, Cristian; Eberhardt, Esther; Schmidt, Roland; Lunden, Lars Kristian; Ørstavik, Kristin; Kaluza, Luisa; Meents, Jannis; Zhang, Zhiping; Carr, Thomas Hedley; Salter, Hugh; Malinowsky, David; Wollberg, Patrik; Krupp, Johannes; Kleggetveit, Inge Petter; Schmelz, Martin; Jørum, Ellen; Namer, Barbara

    2016-01-01

    Gain-of-function mutations in the tetrodotoxin (TTX) sensitive voltage-gated sodium channel (Nav) Nav1.7 have been identified as a key mechanism underlying chronic pain in inherited erythromelalgia. Mutations in TTX resistant channels, such as Nav1.8 or Nav1.9, were recently connected with inherited chronic pain syndromes. Here, we investigated the effects of the p.M650K mutation in Nav1.8 in a 53 year old patient with erythromelalgia by microneurography and patch-clamp techniques. Recordings of the patient’s peripheral nerve fibers showed increased activity dependent slowing (ADS) in CMi and less spontaneous firing compared to a control group of erythromelalgia patients without Nav mutations. To evaluate the impact of the p.M650K mutation on neuronal firing and channel gating, we performed current and voltage-clamp recordings on transfected sensory neurons (DRGs) and neuroblastoma cells. The p.M650K mutation shifted steady-state fast inactivation of Nav1.8 to more hyperpolarized potentials and did not significantly alter any other tested gating behaviors. The AP half-width was significantly broader and the stimulated action potential firing rate was reduced for M650K transfected DRGs compared to WT. We discuss the potential link between enhanced steady state fast inactivation, broader action potential width and the potential physiological consequences. PMID:27598514

  3. Higher sympathetic nerve activity during ventricular (VVI) than during dual-chamber (DDD) pacing

    NASA Technical Reports Server (NTRS)

    Taylor, J. A.; Morillo, C. A.; Eckberg, D. L.; Ellenbogen, K. A.

    1996-01-01

    OBJECTIVES: We determined the short-term effects of single-chamber ventricular pacing and dual-chamber atrioventricular (AV) pacing on directly measured sympathetic nerve activity. BACKGROUND: Dual-chamber AV cardiac pacing results in greater cardiac output and lower systemic vascular resistance than does single-chamber ventricular pacing. However, it is unclear whether these hemodynamic advantages result in less sympathetic nervous system outflow. METHODS: In 13 patients with a dual-chamber pacemaker, we recorded the electrocardiogram, noninvasive arterial pressure (Finapres), respiration and muscle sympathetic nerve activity (microneurography) during 3 min of underlying basal heart rate and 3 min of ventricular and AV pacing at rates of 60 and 100 beats/min. RESULTS: Arterial pressure was lowest and muscle sympathetic nerve activity was highest at the underlying basal heart rate. Arterial pressure increased with cardiac pacing and was greater with AV than with ventricular pacing (change in mean blood pressure +/- SE: 10 +/- 3 vs. 2 +/- 2 mm Hg at 60 beats/min; 21 +/- 5 vs. 14 +/- 2 mm Hg at 100 beats/min; p < 0.05). Sympathetic nerve activity decreased with cardiac pacing and the decline was greater with AV than with ventricular pacing (60 beats/min -40 +/- 11% vs. -17 +/- 7%; 100 beats/min -60 +/- 9% vs. -48 +/- 10%; p < 0.05). Although most patients showed a strong inverse relation between arterial pressure and muscle sympathetic nerve activity, three patients with severe left ventricular dysfunction (ejection fraction < or = 30%) showed no relation between arterial pressure and sympathetic activity. CONCLUSIONS: Short-term AV pacing results in lower sympathetic nerve activity and higher arterial pressure than does ventricular pacing, indicating that cardiac pacing mode may influence sympathetic outflow simply through arterial baroreflex mechanisms. We speculate that the greater incidence of adverse outcomes in patients treated with single-chamber ventricular

  4. Mild central chemoreflex activation does not alter arterial baroreflex function in healthy humans

    PubMed Central

    Simmons, Grant H; Manson, Julie M; Halliwill, John R

    2007-01-01

    We have previously shown that activation of peripheral chemoreceptors with isocapnic hypoxia resets arterial baroreflex control of heart rate and sympathetic vasoconstrictor outflow to higher pressures, without changes in baroreflex gain. We tested the hypothesis that activation of central chemoreceptors with mild hyperoxic hypercapnia also causes resetting of the arterial baroreflex, but that this resetting would not occur with matched volume and frequency hyperpnoea. Baroreflex control of heart rate (n = 16) and muscle sympathetic nerve activity (microneurography; n = 11) was assessed in healthy men and women, age 20–33 years, using the modified Oxford technique during hyperoxic eucapnia, hyperoxic hyperpnoea and hyperoxic hypercapnia (end-tidal PCO2+ 5 mmHg above eucapnia). Baroreflex trials were separated by 30 min of rest. While neither hyperpnoea nor hypercapnia changed mean arterial pressure (92.0 ± 1.8 during eucapnia versus 91.0 ± 1.2 and 90.7 ± 1.4 mmHg during hyperpnoea and hypercapnia; P = 0.427) or muscle sympathetic nerve activity (2301 ± 687 during eucapnia versus 2959 ± 987 and 2272 ± 414 total integrated units min−1 during hyperpnoea and hypercapnia; P = 0.653), heart rate was increased from 59.3 ± 2.7 during eucapnia to 63.2 ± 3.0 and 62.4 ± 2.8 beats min−1 during hyperpnoea and hypercapnia (both P < 0.017). Baroreflex gain was not altered by hyperpnoea or hypercapnia. Thus, acute activation of central chemoreceptors with mild hyperoxic hypercapnia does not affect arterial pressure, sympathetic vasoconstrictor outflow, or baroreflex gain. Heart rate is elevated during hyperoxic hypercapnia, but this response is not different from the increase in heart rate produced by matched volume and frequency hyperpnoea. Therefore, mild activation of central chemoreceptors does not appear to alter arterial baroreflex function. PMID:17640930

  5. Sympathetic nervous system activity is associated with obesity-induced subclinical organ damage in young adults.

    PubMed

    Lambert, Elisabeth; Sari, Carolina Ika; Dawood, Tye; Nguyen, Julie; McGrane, Mariee; Eikelis, Nina; Chopra, Reena; Wong, Chiew; Chatzivlastou, Kanella; Head, Geoff; Straznicky, Nora; Esler, Murray; Schlaich, Markus; Lambert, Gavin

    2010-09-01

    Excess weight is established as a major risk factor for cardiovascular diseases, particularly in young individuals. To get a better understanding of the pathophysiology underlying increased cardiovascular disease risk, we evaluated early signs of organ damage and their possible relationship to sympathetic nervous activity. Eighteen lean (body mass index <25 kg/m(2)) and 25 overweight or obese (body mass index >25 kg/m(2)) healthy university students were included in the study. We comprehensively assessed subclinical target organ damage, including the following: (1) assessment of renal function; (2) left ventricular structure and systolic and diastolic function; and (3) endothelial function. Muscle sympathetic nervous activity was assessed by microneurography. Participants with excess weight had decreased endothelial function (P<0.01), elevated creatinine clearance (P<0.05), increased left ventricular mass index (P<0.05), increased left ventricular wall thickness (P<0.01), lower systolic and diastolic function (P<0.01), and elevated muscle sympathetic nervous activity (P<0.001) compared with lean individuals. In multiple regression analysis, endothelial function was inversely related to muscle sympathetic nervous activity (R(2)=0.244; P<0.05), whereas creatinine clearance and left ventricular mass index were positively related to muscle sympathetic nervous activity, after adjustment for body mass index, sex, and blood pressure (R(2)=0.318, P<0.01 and R(2)=0.312, P<0.05, respectively). Excess weight in young individuals is associated with subclinical alterations in renal and endothelial function, as well as in the structure of the heart, even in the absence of hypertension. Sympathetic activity is closely associated with cardiovascular and renal alterations observed in these subjects.

  6. Vestibulosympathetic reflex during mental stress

    NASA Technical Reports Server (NTRS)

    Carter, Jason R.; Ray, Chester A.; Cooke, William H.

    2002-01-01

    Increases in sympathetic neural activity occur independently with either vestibular or mental stimulation, but it is unknown whether sympathetic activation is additive or inhibitive when both stressors are combined. The purpose of the present study was to investigate the combined effects of vestibular and mental stimulation on sympathetic neural activation and arterial pressure in humans. Muscle sympathetic nerve activity (MSNA), arterial pressure, and heart rate were recorded in 10 healthy volunteers in the prone position during 1) head-down rotation (HDR), 2) mental stress (MS; using arithmetic), and 3) combined HDR and MS. HDR significantly (P < 0.05) increased MSNA (9 +/- 2 to 13 +/- 2 bursts/min). MS significantly increased MSNA (8 +/- 2 to 13 +/- 2 bursts/min) and mean arterial pressure (87 +/- 2 to 101 +/- 2 mmHg). Combined HDR and MS significantly increased MSNA (9 +/- 1 to 16 +/- 2 bursts/min) and mean arterial pressure (89 +/- 2 to 100 +/- 3 mmHg). Increases in MSNA (7 +/- 1 bursts/min) during the combination trial were not different from the algebraic sum of each trial performed alone (8 +/- 2 bursts/min). We conclude that the interaction for MSNA and arterial pressure is additive during combined vestibular and mental stimulation. Therefore, vestibular- and stress-mediated increases of MSNA appear to occur independently in humans.

  7. Limb neurovascular control during altered otolithic input in humans

    NASA Technical Reports Server (NTRS)

    Monahan, Kevin D.; Ray, Chester A.

    2002-01-01

    Head-down rotation (HDR), which activates the vestibulosympathetic reflex, increases leg muscle sympathetic nerve activity (MSNA) and produces calf vasoconstriction with no change in either cardiac output or arterial blood pressure. Based on animal studies, it was hypothesized that differential control of arm and leg MSNA explains why HDR does not alter arterial blood pressure. Fifteen healthy subjects were studied. Heart rate, arterial blood pressure, forearm and calf blood flow, and leg MSNA responses were measured during HDR in these subjects. Simultaneous recordings of arm and leg MSNA were obtained from five of the subjects. Forearm and calf blood flow, vascular conductances, and vascular resistances were similar before HDR, as were arm and leg MSNA. HDR elicited similar significant increases in leg (Delta 6 +/- 1 bursts min(-1); 59 +/- 16 % from baseline) and arm MSNA (Delta 5 +/- 1 bursts min(-1); 80 +/- 28 % from baseline). HDR significantly decreased calf (-19 +/- 2 %) and forearm vascular conductance (-12 +/- 2 %) and significantly increased calf (25 +/- 4 %) and forearm vascular resistance (15 +/- 2 %), with 60 % greater vasoconstriction in the calf than in the forearm. Arterial blood pressure and heart rate were not altered by HDR. These results indicate that there is no differential control of MSNA in the arm and leg during altered feedback from the otolith organs in humans, but that greater vasoconstriction occurs in the calf than in the forearm. These findings indicate that vasodilatation occurs in other vascular bed(s) to account for the lack of increase in arterial blood pressure during HDR.

  8. Activity.

    ERIC Educational Resources Information Center

    Clearing: Nature and Learning in the Pacific Northwest, 1984

    1984-01-01

    Presents three activities: (1) investigating succession in a schoolground; (2) investigating oak galls; and (3) making sun prints (photographs made without camera or darkroom). Each activity includes a list of materials needed and procedures used. (JN)

  9. Sympathetic vascular transduction is augmented in young normotensive blacks

    NASA Technical Reports Server (NTRS)

    Ray, Chester A.; Monahan, Kevin D.

    2002-01-01

    The purpose of the present study was to determine sympathetic vascular transduction in young normotensive black and white adults. We hypothesized that blacks would demonstrate augmented transduction of muscle sympathetic nerve activity (MSNA) into vascular resistance. To test this hypothesis, MSNA, forearm blood flow, heart rate, and arterial blood pressure were measured during lower body negative pressure (LBNP). At rest, no differences existed in arterial blood pressure, heart rate, forearm blood flow, and forearm vascular resistance (FVR). Likewise, LBNP elicited comparable responses of these variables for blacks and whites. Baseline MSNA did not differ between blacks and whites, but whites demonstrated greater increases during LBNP (28 +/- 7 vs. 55 +/- 18%, 81 +/- 21 vs. 137 +/- 42%, 174 +/- 81 vs. 556 +/- 98% for -5, -15, and -40 mmHg LBNP, respectively; P < 0.001). Consistent with smaller increases in MSNA but similar FVR responses during LBNP, blacks demonstrated greater sympathetic vascular transduction (%FVR/%MSNA) than whites (0.95 +/- 0.07 vs. 0.82 +/- 0.07 U; 0.82 +/- 0.11 vs. 0.64 +/- 0.09 U; 0.95 +/- 0.37 vs. 0.35 +/- 0.09 U; P < 0.01). In summary, young whites demonstrate greater increases in MSNA during baroreceptor unloading than age-matched normotensive blacks. However, more importantly, for a given increase in MSNA, blacks demonstrate greater forearm vasoconstriction than whites. This finding may contribute to augmented blood pressure reactivity in blacks.

  10. Identification of the Anti-Aflatoxinogenic Activity of Micromeria graeca and Elucidation of Its Molecular Mechanism in Aspergillus flavus

    PubMed Central

    El Khoury, Rhoda; Caceres, Isaura; Puel, Olivier; Bailly, Sylviane; Atoui, Ali; Oswald, Isabelle P.; El Khoury, André; Bailly, Jean-Denis

    2017-01-01

    Of all the food-contaminating mycotoxins, aflatoxins, and most notably aflatoxin B1 (AFB1), are found to be the most toxic and economically costly. Green farming is striving to replace fungicides and develop natural preventive strategies to minimize crop contamination by these toxic fungal metabolites. In this study, we demonstrated that an aqueous extract of the medicinal plant Micromeria graeca—known as hyssop—completely inhibits aflatoxin production by Aspergillus flavus without reducing fungal growth. The molecular inhibitory mechanism was explored by analyzing the expression of 61 genes, including 27 aflatoxin biosynthesis cluster genes and 34 secondary metabolism regulatory genes. This analysis revealed a three-fold down-regulation of aflR and aflS encoding the two internal cluster co-activators, resulting in a drastic repression of all aflatoxin biosynthesis genes. Hyssop also targeted fifteen regulatory genes, including veA and mtfA, two major global-regulating transcription factors. The effect of this extract is also linked to a transcriptomic variation of several genes required for the response to oxidative stress such as msnA, srrA, catA, cat2, sod1, mnsod, and stuA. In conclusion, hyssop inhibits AFB1 synthesis at the transcriptomic level. This aqueous extract is a promising natural-based solution to control AFB1 contamination. PMID:28257049

  11. Folic acid supplementation increases cutaneous vasodilator sensitivity to sympathetic nerve activity in older adults.

    PubMed

    Stanhewicz, Anna E; Greaney, Jody L; Alexander, Lacy M; Kenney, W Larry

    2017-02-22

    During heat stress, blunted increases in skin sympathetic nervous system activity (SSNA) and reductions in end-organ vascular responsiveness contribute to the age-related reduction in reflex cutaneous vasodilation. In older adults, folic acid supplementation improves the cutaneous vascular conductance (CVC) response to passive heating; however, the influence of folic acid supplementation on SSNA:CVC transduction is unknown. Fourteen older adults (66±1yrs, 8M/6F) ingested folic acid (5mg·day(-1)) or placebo for 6 weeks in a randomized, double-blind, crossover design. In protocol 1, esophageal temperature (Tes) was increased by 1.0ºC (water-perfused suit) while SSNA (peroneal microneurography) and red cell flux in the innervated dermatome (laser Doppler flowmetry; dorsum of the foot) were continuously measured. In protocol 2, two intradermal microdialysis fibers were placed in the skin of the lateral calf for graded infusions of acetylcholine (ACh; 10(-10) to 10(-1)M) with and without nitric oxide synthase (NOS) blockade (20mM L-NAME). Folic acid improved reflex vasodilation (46±4% vs. 31±3 %CVCmax for placebo; P<0.001) without affecting the increase in SSNA (Δ506±104% vs. Δ415±73% for placebo; NS). Folic acid increased the slope of the SSNA:CVC relation (0.08±0.02 vs. 0.05±0.01 for placebo; P<0.05) and extended the response range. Folic acid augmented ACh-induced vasodilation (83±3% vs. 66±4 %CVCmax for placebo; P=0.002); however there was no difference between treatments at the NOS-inhibited site (53±4% vs. 52±4% CVCmax for placebo; NS). These data demonstrate that folic acid supplementation enhances reflex vasodilation by increasing the sensitivity of skin arterioles to central sympathetic nerve outflow during hyperthermia in aged human subjects.

  12. Augmented supraorbital skin sympathetic nerve activity responses to symptom trigger events in rosacea patients

    PubMed Central

    Metzler-Wilson, Kristen; Toma, Kumika; Sammons, Dawn L.; Mann, Sarah; Jurovcik, Andrew J.; Demidova, Olga

    2015-01-01

    Facial flushing in rosacea is often induced by trigger events. However, trigger causation mechanisms are currently unclear. This study tested the central hypothesis that rosacea causes sympathetic and axon reflex-mediated alterations resulting in trigger-induced symptomatology. Twenty rosacea patients and age/sex-matched controls participated in one or a combination of symptom triggering stressors. In protocol 1, forehead skin sympathetic nerve activity (SSNA; supraorbital microneurography) was measured during sympathoexcitatory mental (2-min serial subtraction of novel numbers) and physical (2-min isometric handgrip) stress. In protocol 2, forehead skin blood flow (laser-Doppler flowmetry) and transepithelial water loss/sweat rate (capacitance hygrometry) were measured during sympathoexcitatory heat stress (whole body heating by perfusing 50°C water through a tube-lined suit). In protocol 3, cheek, forehead, forearm, and palm skin blood flow were measured during nonpainful local heating to induce axon reflex vasodilation. Heart rate (HR) and mean arterial pressure (MAP) were recorded via finger photoplethysmography to calculate cutaneous vascular conductance (CVC; flux·100/MAP). Higher patient transepithelial water loss was observed (rosacea 0.20 ± 0.02 vs. control 0.10 ± 0.01 mg·cm−2·min−1, P < 0.05). HR and MAP changes were not different between groups during sympathoexcitatory stressors or local heating. SSNA during early mental (32 ± 9 and 9 ± 4% increase) and physical (25 ± 4 and 5 ± 1% increase, rosacea and controls, respectively) stress was augmented in rosacea (both P < 0.05). Heat stress induced more rapid sweating and cutaneous vasodilation onset in rosacea compared with controls. No axon reflex vasodilation differences were observed between groups. These data indicate that rosacea affects SSNA and that hyperresponsiveness to trigger events appears to have a sympathetic component. PMID:26133800

  13. Acupuncture attenuates exercise-induced increases in skin sympathetic nerve activity.

    PubMed

    Toma, Kumika; Walkowski, Stevan; Metzler-Wilson, Kristen; Wilson, Thad E

    2011-07-05

    To identify the effect of acupuncture on skin sympathetic nerve activity (SSNA), 17 healthy subjects (7 male and 10 female) underwent LI4 acupuncture and sham needle insertion during resting or elevated SSNA conditions. In Protocol 1 (resting SSNA), subjects received a 10 min sham followed by 10 min of LI4 acupuncture during resting conditions. In Protocol 2 (elevated SSNA), subjects performed 10 min of submaximal intermittent handgrip (2:4s work to rest interval at 37±3% of maximal voluntary contraction) during sham and LI4 acupuncture conditions. SSNA (peroneal nerve microneurography), heart rate (ECG), and mean arterial blood pressure (finger photoplethysmography) were measured and normalized to baseline. SSNA, heart rate, and mean arterial blood pressure were not significantly altered during resting conditions (Protocol 1). During handgrip (Protocol 2), SSNA significantly increased with the sham treatment (+15.3±8.8, +11.1±5.9, and +24.3±13.0% at minutes 1, 5, and 10, respectively), while LI4 acupuncture attenuated this increase (-1.6±7.6, 0.0±4.3, and +2.2±11.2% at minutes 1, 5, and 10, respectively). Heart rate and mean arterial blood pressure increased during handgrip (Protocol 2), but no differences were observed between sham and LI4 acupuncture treatments. These results suggest that acupuncture does not affect resting SSNA in healthy subjects, however if SSNA is acutely elevated above baseline levels, acupuncture has the capacity to attenuate the increased SSNA.

  14. Augmented supraorbital skin sympathetic nerve activity responses to symptom trigger events in rosacea patients.

    PubMed

    Metzler-Wilson, Kristen; Toma, Kumika; Sammons, Dawn L; Mann, Sarah; Jurovcik, Andrew J; Demidova, Olga; Wilson, Thad E

    2015-09-01

    Facial flushing in rosacea is often induced by trigger events. However, trigger causation mechanisms are currently unclear. This study tested the central hypothesis that rosacea causes sympathetic and axon reflex-mediated alterations resulting in trigger-induced symptomatology. Twenty rosacea patients and age/sex-matched controls participated in one or a combination of symptom triggering stressors. In protocol 1, forehead skin sympathetic nerve activity (SSNA; supraorbital microneurography) was measured during sympathoexcitatory mental (2-min serial subtraction of novel numbers) and physical (2-min isometric handgrip) stress. In protocol 2, forehead skin blood flow (laser-Doppler flowmetry) and transepithelial water loss/sweat rate (capacitance hygrometry) were measured during sympathoexcitatory heat stress (whole body heating by perfusing 50°C water through a tube-lined suit). In protocol 3, cheek, forehead, forearm, and palm skin blood flow were measured during nonpainful local heating to induce axon reflex vasodilation. Heart rate (HR) and mean arterial pressure (MAP) were recorded via finger photoplethysmography to calculate cutaneous vascular conductance (CVC; flux·100/MAP). Higher patient transepithelial water loss was observed (rosacea 0.20 ± 0.02 vs. control 0.10 ± 0.01 mg·cm(-2)·min(-1), P < 0.05). HR and MAP changes were not different between groups during sympathoexcitatory stressors or local heating. SSNA during early mental (32 ± 9 and 9 ± 4% increase) and physical (25 ± 4 and 5 ± 1% increase, rosacea and controls, respectively) stress was augmented in rosacea (both P < 0.05). Heat stress induced more rapid sweating and cutaneous vasodilation onset in rosacea compared with controls. No axon reflex vasodilation differences were observed between groups. These data indicate that rosacea affects SSNA and that hyperresponsiveness to trigger events appears to have a sympathetic component.

  15. Activities.

    ERIC Educational Resources Information Center

    Bippert, Judy

    1993-01-01

    Presents activities designed to give students an opportunity to solve concrete problems involving spatial relationships and logical thinking utilizing hands-on manipulatives. Provides teacher instructions and four reproducible worksheets. (MDH)

  16. Activities.

    ERIC Educational Resources Information Center

    Kincaid, Charlene; And Others

    1993-01-01

    Presents an activity in which students collect and organize data from a real-world simulation of the scientific concept of half life. Students collect data using a marble sifter, analyze the data using a graphing calculator, and determine an appropriate mathematical model. Includes reproducible worksheets. (MDH)

  17. The vestibulosympathetic reflex in humans: neural interactions between cardiovascular reflexes

    NASA Technical Reports Server (NTRS)

    Ray, Chester A.; Monahan, Kevin D.

    2002-01-01

    1. Over the past 5 years, there has been emerging evidence that the vestibular system regulates sympathetic nerve activity in humans. We have studied this issue in humans by using head-down rotation (HDR) in the prone position. 2. These studies have clearly demonstrated increases in muscle sympathetic nerve activity (MSNA) and calf vascular resistance during HDR. These responses are mediated by engagement of the otolith organs and not the semicircular canals. 3. However, differential activation of sympathetic nerve activity has been observed during HDR. Unlike MSNA, skin sympathetic nerve activity does not increase with HDR. 4. Examination of the vestibulosympathetic reflex with other cardiovascular reflexes (i.e. barorereflexes and skeletal muscle reflexes) has shown an additive interaction for MSNA. 5. The additive interaction between the baroreflexes and vestibulosympathetic reflex suggests that the vestibular system may assist in defending against orthostatic challenges in humans by elevating MSNA beyond that of the baroreflexes. 6. In addition, the further increase in MSNA via otolith stimulation during isometric handgrip, when arterial pressure is elevated markedly, indicates that the vestibulosympathetic reflex is a powerful activator of MSNA and may contribute to blood pressure and flow regulation during dynamic exercise. 7. Future studies will help evaluate the importance of the vestibulosympathetic reflex in clinical conditions associated with orthostatic hypotension.

  18. Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans

    NASA Technical Reports Server (NTRS)

    Wilson, T. E.; Cui, J.; Crandall, C. G.

    2001-01-01

    1. Prior findings suggest that baroreflexes are capable of modulating skin blood flow, but the effects of baroreceptor loading/unloading on sweating are less clear. Therefore, this project tested the hypothesis that pharmacologically induced alterations in arterial blood pressure in heated humans would lead to baroreflex-mediated changes in both skin sympathetic nerve activity (SSNA) and sweat rate. 2. In seven subjects mean arterial blood pressure was lowered (approximately 8 mmHg) and then raised (approximately 13 mmHg) by bolus injections of sodium nitroprusside and phenylephrine, respectively. Moreover, in a separate protocol, arterial blood pressure was reduced via steady-state administration of sodium nitroprusside. In both normothermia and heat-stress conditions the following responses were monitored: sublingual and mean skin temperatures, heart rate, beat-by-beat blood pressure, skin blood flow (laser-Doppler flowmetry), local sweat rate and SSNA (microneurography from peroneal nerve). 3. Whole-body heating increased skin and sublingual temperatures, heart rate, cutaneous blood flow, sweat rate and SSNA, but did not change arterial blood pressure. Heart rate was significantly elevated (from 74 +/- 3 to 92 +/- 4 beats x min(-1); P < 0.001) during bolus sodium nitroprusside-induced reductions in blood pressure, and significantly reduced (from 92 +/- 4 to 68 +/- 4 beats x min(-1); P < 0.001) during bolus phenylephrine-induced elevations in blood pressure, thereby demonstrating normal baroreflex function in these subjects. 4. Neither SSNA nor sweat rate was altered by rapid (bolus infusion) or sustained (steady-state infusion) changes in blood pressure regardless of the thermal condition. 5. These data suggest that SSNA and sweat rate are not modulated by arterial baroreflexes in normothermic or moderately heated individuals.

  19. Sympathetic nerve hyperactivity of essential hypertension is lower in postmenopausal women than men.

    PubMed

    Hogarth, A J; Burns, J; Mackintosh, A F; Mary, D A S G

    2008-08-01

    Sympathetic activation has been associated with the development and complications of hypertension. While the prevalence of hypertension and its cardiovascular risks in women are found to be less than in men and tend to become similar to men after the menopause, there have been no data on the level of sympathetic activation in postmenopausal women relative to men. Therefore, we planned to find out whether muscle sympathetic nerve hyperactivity of essential hypertension (EHT) in postmenopausal women is different from that in matched men. We quantified muscle sympathetic nerve activity (MSNA) as mean frequency of single units (s-MSNA) and multiunit bursts (b-MSNA) in 21 postmenopausal women with EHT (W-EHT) relative to 21 matched men with EHT (M-EHT), in comparison to two control groups of 21 normal women (W-NC) and 21 men (M-NC), respectively. The EHT groups had greater MSNA indices than NC groups. W-EHT had lower (P<0.05) s-MSNA (63+/-22.7 impulses per 100 cardiac beats) than M-EHT (78+/-11.2 impulses per 100 cardiac beats). W-NC had lower (P<0.05) s-MSNA (53+/-12.4 impulses per 100 cardiac beats) than M-NC (65+/-16.3 impulses per 100 cardiac beats). Similar results were obtained for b-MSNA. Postmenopausal women with EHT had lower level of central sympathetic hyperactivity than men. Similarly, normal postmenopausal women had lower MSNA than men. These findings suggest that postmenopausal women continue to have a lower sympathetic nerve activity than men even after the development of EHT, and that this could have implications for gender-specific management of hypertension.

  20. Interactive effect of hypoxia and otolith organ engagement on cardiovascular regulation in humans

    NASA Technical Reports Server (NTRS)

    Monahan, Kevin D.; Ray, Chester A.

    2002-01-01

    We determined the interaction between the vestibulosympathetic reflex and the arterial chemoreflex in 12 healthy subjects. Subjects performed three trials in which continuous recordings of muscle sympathetic nerve activity (MSNA), mean arterial blood pressure (MAP), heart rate (HR), and arterial oxygen saturation were obtained. First, in prone subjects the otolith organs were engaged by use of head-down rotation (HDR). Second, the arterial chemoreflex was activated by inspiration of hypoxic gas (10% O2 and 90% N2) for 7 min with HDR being performed during minute 6. Third, hypoxia was repeated (15 min) with HDR being performed during minute 14. HDR [means +/- SE; increase (Delta)7 +/- 1 bursts/min and Delta50 +/- 11% for burst frequency and total MSNA, respectively; P < 0.05] and hypoxia (Delta6 +/- 2 bursts/min and Delta62 +/- 29%; P < 0.05) increased MSNA. Additionally, MSNA increased when HDR was performed during hypoxia (Delta11 +/- 2 bursts/min and Delta127 +/- 57% change from normoxia; P < 0.05). These increases in MSNA were similar to the algebraic sum of the individual increase in MSNA elicited by HDR and hypoxia (Delta13 +/- 1 bursts/min and Delta115 +/- 36%). Increases in MAP (Delta3 +/- 1 mmHg) and HR (Delta19 +/- 1 beats/min) during combined HDR and hypoxia generally were smaller (P < 0.05) than the algebraic sum of the individual responses (Delta5 +/- 1 mmHg and Delta24 +/- 2 beats/min for MAP and HR, respectively; P < 0.05). These findings indicate an additive interaction between the vestibulosympathetic reflex and arterial chemoreflex for MSNA. Therefore, it appears that MSNA outputs between the vestibulosympathetic reflex and arterial chemoreflex are independent of one another in humans.

  1. Sustained sympathetic and blood pressure reduction 1 year after renal denervation in patients with resistant hypertension.

    PubMed

    Hering, Dagmara; Marusic, Petra; Walton, Antony S; Lambert, Elisabeth A; Krum, Henry; Narkiewicz, Krzysztof; Lambert, Gavin W; Esler, Murray D; Schlaich, Markus P

    2014-07-01

    Renal denervation (RDN) reduces muscle sympathetic nerve activity (MSNA) and blood pressure (BP) in resistant hypertension. Although a persistent BP-lowering effect has been demonstrated, the long-term effect on MSNA remains elusive. We investigated whether RDN influences MSNA over time. Office BP and MSNA were obtained at baseline, 3, 6, and 12 months after RDN in 35 patients with resistant hypertension. Office BP averaged 166±22/88±19 mm Hg, despite the use of an average of 4.8±2.1 antihypertensive drugs. Baseline MSNA was 51±11 bursts/min ≈2- to 3-fold higher than the level observed in healthy controls. Mean office systolic and diastolic BP significantly decreased by -12.6±18.3/-6.5±9.2, -16.1±25.6/-8.6±12.9, and -21.2±29.1/-11.1±12.9 mm Hg (P<0.001 for both systolic BP and diastolic BP) with RDN at 3-, 6-, and 12-month follow-up, respectively. MSNA was reduced by -8±12, -6±12, and -6±11 bursts/min (P<0.01) at 3-, 6-, and 12-month follow-up. The reduction in MSNA was maintained, despite a progressive fall in BP over time. No such changes were observed in 7 control subjects at 6-month follow-up. These findings confirm previous reports on the favorable effects of RDN on elevated BP and demonstrate sustained reduction of central sympathetic outflow ≤1-year follow-up in patients with resistant hypertension and high baseline MSNA. These observations are compatible with the hypothesis of a substantial contribution of afferent renal nerve signaling to increased BP in resistant hypertension and argue against a relevant reinnervation at 1 year after procedure.

  2. Sympathetic adaptations to one-legged training

    NASA Technical Reports Server (NTRS)

    Ray, C. A.

    1999-01-01

    The purpose of the present study was to determine the effect of leg exercise training on sympathetic nerve responses at rest and during dynamic exercise. Six men were trained by using high-intensity interval and prolonged continuous one-legged cycling 4 day/wk, 40 min/day, for 6 wk. Heart rate, mean arterial pressure (MAP), and muscle sympathetic nerve activity (MSNA; peroneal nerve) were measured during 3 min of upright dynamic one-legged knee extensions at 40 W before and after training. After training, peak oxygen uptake in the trained leg increased 19 +/- 2% (P < 0.01). At rest, heart rate decreased from 77 +/- 3 to 71 +/- 6 beats/min (P < 0.01) with no significant changes in MAP (91 +/- 7 to 91 +/- 11 mmHg) and MSNA (29 +/- 3 to 28 +/- 1 bursts/min). During exercise, both heart rate and MAP were lower after training (108 +/- 5 to 96 +/- 5 beats/min and 132 +/- 8 to 119 +/- 4 mmHg, respectively, during the third minute of exercise; P < 0.01). MSNA decreased similarly from rest during the first 2 min of exercise both before and after training. However, MSNA was significantly less during the third minute of exercise after training (32 +/- 2 to 22 +/- 3 bursts/min; P < 0.01). This training effect on MSNA remained when MSNA was expressed as bursts per 100 heartbeats. Responses to exercise in five untrained control subjects were not different at 0 and 6 wk. These results demonstrate that exercise training prolongs the decrease in MSNA during upright leg exercise and indicates that attenuation of MSNA to exercise reported with forearm training also occurs with leg training.

  3. Limb congestion enhances the synchronization of sympathetic outflow with muscle contraction

    NASA Technical Reports Server (NTRS)

    Mostoufi-Moab, S.; Herr, M. D.; Silber, D. H.; Gray, K. S.; Leuenberger, U. A.; Sinoway, L. I.

    2000-01-01

    In this report, we examined if the synchronization of muscle sympathetic nerve activity (MSNA) with muscle contraction is enhanced by limb congestion. To explore this relationship, we applied signal-averaging techniques to the MSNA signal obtained during short bouts of forearm contraction (2-s contraction/3-s rest cycle) at 40% maximal voluntary contraction for 5 min. We performed this analysis before and after forearm venous congestion; an intervention that augments the autonomic response to sustained static muscle contractions via a local effect on muscle afferents. There was an increased percentage of the MSNA noted during second 2 of the 5-s contraction/rest cycles. The percentage of total MSNA seen during this particular second increased from minute 1 to 5 of contraction and was increased further by limb congestion (control minute 1 = 25.6 +/- 2.0%, minute 5 = 32.8 +/- 2.2%; limb congestion minute 1 = 29.3 +/- 2.1%, minute 5 = 37.8 +/- 3.9%; exercise main effect <0.005; limb congestion main effect P = 0.054). These changes in the distribution of signal-averaged MSNA were seen despite the fact that the mean number of sympathetic discharges did not increase over baseline. We conclude that synchronization of contraction and MSNA is seen during short repetitive bouts of handgrip. The sensitizing effect of contraction time and limb congestion are apparently due to feedback from muscle afferents within the exercising muscle.

  4. Oscillatory patterns in sympathetic neural discharge and cardiovascular variables during orthostatic stimulus

    NASA Technical Reports Server (NTRS)

    Furlan, R.; Porta, A.; Costa, F.; Tank, J.; Baker, L.; Schiavi, R.; Robertson, D.; Malliani, A.; Mosqueda-Garcia, R.

    2000-01-01

    BACKGROUND: We tested the hypothesis that a common oscillatory pattern might characterize the rhythmic discharge of muscle sympathetic nerve activity (MSNA) and the spontaneous variability of heart rate and systolic arterial pressure (SAP) during a physiological increase of sympathetic activity induced by the head-up tilt maneuver. METHODS AND RESULTS: Ten healthy subjects underwent continuous recordings of ECG, intra-arterial pressure, respiratory activity, central venous pressure, and MSNA, both in the recumbent position and during 75 degrees head-up tilt. Venous samplings for catecholamine assessment were obtained at rest and during the fifth minute of tilt. Spectrum and cross-spectrum analyses of R-R interval, SAP, and MSNA variabilities and of respiratory activity provided the low (LF, 0.1 Hz) and high frequency (HF, 0.27 Hz) rhythmic components of each signal and assessed their linear relationships. Compared with the recumbent position, tilt reduced central venous pressure, but blood pressure was unchanged. Heart rate, MSNA, and plasma epinephrine and norepinephrine levels increased, suggesting a marked enhancement of overall sympathetic activity. During tilt, LF(MSNA) increased compared with the level in the supine position; this mirrored similar changes observed in the LF components of R-R interval and SAP variabilities. The increase of LF(MSNA) was proportional to the amount of the sympathetic discharge. The coupling between LF components of MSNA and R-R interval and SAP variabilities was enhanced during tilt compared with rest. CONCLUSIONS: During the sympathetic activation induced by tilt, a similar oscillatory pattern based on an increased LF rhythmicity characterized the spontaneous variability of neural sympathetic discharge, R-R interval, and arterial pressure.

  5. Sympathetic and cardiovascular responses to venous distension in an occluded limb.

    PubMed

    Cui, Jian; Leuenberger, Urs A; Gao, Zhaohui; Sinoway, Lawrence I

    2011-12-01

    We recently showed that a fixed volume (i.e., 40 ml) of saline infused into the venous circulation of an arterially occluded vascular bed increases muscle sympathetic nerve activity (MSNA) and blood pressure. In the present report, we hypothesized that the volume and rate of infusion would influence the magnitude of the sympathetic response. Blood pressure, heart rate, and MSNA were assessed in 13 young healthy subjects during forearm saline infusions (arrested circulation). The effects of different volumes of saline (i.e., 2%, 3%, 4%, or 5% forearm volume at 30 ml/min) and different rates of infusion (i.e., 5% forearm volume at 10, 20, or 30 ml/min) were evaluated. MSNA and blood pressure responses were linked with the infusion volume. Infusion of 5% of forearm volume evoked greater MSNA responses than did infusion of 2% of forearm volume (Δ11.6 ± 1.9 vs. Δ3.1 ± 1.8 bursts/min and Δ332 ± 105 vs. Δ38 ± 32 units/min, all P < 0.05). Moreover, greater MSNA responses were evoked by saline infusion at 30 ml/min than 10 ml/min (P < 0.05). Sonographic measurements confirmed that the saline infusions induced forearm venous distension. The results suggest that volume and rate of saline infusion are important factors in evoking sympathetic activation. We postulate that venous distension contributes to cardiovascular autonomic adjustment in humans.

  6. Muscle sympathetic nerve responses to physiological changes in prostaglandin production in humans

    NASA Technical Reports Server (NTRS)

    Doerzbacher, K. J.; Ray, C. A.

    2001-01-01

    Previous studies suggest that prostaglandins may contribute to exercise-induced increases in muscle sympathetic nerve activity (MSNA). To test this hypothesis, MSNA was measured at rest and during exercise before and after oral administration of ketoprofen, a cyclooxygenase inhibitor, or placebo. Twenty-one subjects completed two bouts of graded dynamic and isometric handgrip to fatigue. Each exercise bout was followed by 2 min of postexercise muscle ischemia. The second exercise bouts were performed after 60 min of rest in which 11 subjects were given ketoprofen (300 mg) and 10 subjects received a placebo. Ketoprofen significantly lowered plasma thromboxane B(2) in the drug group (from 36 +/- 6 to 22 +/- 3 pg/ml, P < 0.04), whereas thromboxane B(2) in the placebo group increased from 40 +/- 5 to 61 +/- 9 pg/ml from trial 1 to trial 2 (P < 0.008). Ketoprofen and placebo did not change sympathetic and cardiovascular responses to dynamic handgrip, isometric handgrip, and postexercise muscle ischemia. There was no relationship between thromboxane B(2) concentrations and MSNA or arterial pressure responses during both exercise modes. The data indicate that physiological increases or decreases in prostaglandins do not alter exercise-induced increases in MSNA and arterial pressure in humans. These findings suggest that contraction-induced metabolites other than prostaglandins mediate MSNA responses to exercise in humans.

  7. Sympathetic neural adaptations to exercise training in humans.

    PubMed

    Carter, Jason R; Ray, Chester A

    2015-03-01

    Physiological adaptations to exercise training are well recognized and contribute importantly to health and fitness. Cardiovascular diseases, such as hypertension and heart failure, are often associated with elevated activity of the sympathetic nervous system. This review aims to provide comprehensive overview on the role of exercise training on muscle sympathetic nerve activity (MSNA) regulation in humans, with a focus on recent advances in at-risk populations. Collectively, these studies converge to demonstrate that aerobic exercise training reduces resting MSNA in populations at heightened cardiovascular risk, but do not appear to alter resting MSNA in healthy adults. We provide directions for future research which might address gaps in our knowledge regarding sympathoneural adaptations to exercise training.

  8. Acute Response to Unilateral Unipolar Electrical Carotid Sinus Stimulation in Patients With Resistant Arterial Hypertension.

    PubMed

    Heusser, Karsten; Tank, Jens; Brinkmann, Julia; Menne, Jan; Kaufeld, Jessica; Linnenweber-Held, Silvia; Beige, Joachim; Wilhelmi, Mathias; Diedrich, André; Haller, Hermann; Jordan, Jens

    2016-03-01

    Bilateral bipolar electric carotid sinus stimulation acutely reduced muscle sympathetic nerve activity (MSNA) and blood pressure (BP) in patients with resistant arterial hypertension but is no longer available. The second-generation device uses a smaller unilateral unipolar disk electrode to reduce invasiveness while saving battery life. We hypothesized that the second-generation device acutely lowers BP and MSNA in treatment-resistant hypertensive patients. Eighteen treatment-resistant hypertensive patients (9 women/9 men; 53±11 years; 33±5 kg/m(2)) on stable medications have been included in the study. We monitored finger and brachial BP, heart rate, and MSNA. Without stimulation, BP was 165±31/91±18 mm Hg, heart rate was 75±17 bpm, and MSNA was 48±14 bursts per minute. Acute stimulation with intensities producing side effects that were tolerable in the short term elicited interindividually variable changes in systolic BP (-16.9±15.0 mm Hg; range, 0.0 to -40.8 mm Hg; P=0.002), heart rate (-3.6±3.6 bpm; P=0.004), and MSNA (-2.0±5.8 bursts per minute; P=0.375). Stimulation intensities had to be lowered in 12 patients to avoid side effects at the expense of efficacy (systolic BP, -6.3±7.0 mm Hg; range, 2.8 to -14.5 mm Hg; P=0.028 and heart rate, -1.5±2.3 bpm; P=0.078; comparison against responses with side effects). Reductions in diastolic BP and MSNA (total activity) were correlated (r(2)=0.329; P=0.025). In our patient cohort, unilateral unipolar electric baroreflex stimulation acutely lowered BP. However, side effects may limit efficacy. The approach should be tested in a controlled comparative study.

  9. An Acute Bout of a Controlled Breathing Frequency Lowers Sympathetic Neural Outflow but not Blood Pressure in Healthy Normotensive Subjects

    PubMed Central

    MCCLAIN, SHANNON L.; BROOKS, ALEXA M.; JARVIS, SARA S.

    2017-01-01

    Controlled or paced breathing is often used as a stress reduction technique but the impact on blood pressure (BP) and sympathetic outflow have not been consistently reported. The purpose of this study was to determine whether a controlled breathing (12 breaths/min, CB) rate would be similar to an individual’s spontaneous breathing (SB) rate. Secondly, would a CB rate of 12 breaths/min alter heart rate (HR), BP, and indices of muscle sympathetic nerve activity (MSNA). Twenty-one subjects (10 women, 11 men) performed two trials: SB, where the subject chose a comfortable breathing rate; and CB, where the subject breathed at a pace of 12 breaths/min. Each trial was 6 min during which respiratory waveforms, HR, BP (systolic, SBP; diastolic, DBP), and MSNA were recorded. During CB, the 6 min average breathing frequency (14±4 vs 12±1 breaths/min, P<0.05 for SB and CB, respectively), MSNA burst frequency (18±12 vs 14±10 bursts/min, P<0.01) and MSNA burst incidence (28±19 vs 21± 6 bursts/100 heart beats, P<0.01) were significantly lower than during SB. HR (66±9 vs 67±9 beats/min, P<0.05) was higher during CB. SBP (120±13 vs 121±15 mmHg, P=0.741), DBP (56±8 vs 57±9 mmHg, P=0.768), and MSNA total activity (166±94 vs 145±102 a.u./min, P=0.145) were not different between the breathing conditions. In conclusion, an acute reduction in breathing frequency such as that observed during CB elicited a decrease in indices of MSNA (burst frequency and incidence) with no change in BP. PMID:28344733

  10. Contrasting effects of phentolamine and nitroprusside on neural and cardiovascular variability.

    PubMed

    van de Borne, P; Rahnama, M; Mezzetti, S; Montano, N; Porta, A; Degaute, J P; Somers, V K

    2001-08-01

    The relative contributions of a central neural oscillator and of the delay in alpha-adrenergic transmission within the baroreflex loop in the predominance of low-frequency (LF) cardiovascular variability during sympathetic activation in humans are unclear. We measured R-R interval (RR), muscle sympathetic nerve activity (MSNA), blood pressure (BP), and their variability in 10 normal subjects during sympathetic activation achieved by BP lowering with sodium nitroprusside (SNP) and alpha-adrenergic blockade using phentolamine. SNP and phentolamine induced comparable reductions in BP (P > 0.25). Despite tachycardia and sympathetic activation with both SNP and phentolamine, LF variability in RR, MSNA, and BP increased during SNP and decreased during phentolamine (SNP: RR +20 +/- 6%, MSNA +3 +/- 5%, systolic BP +9 +/- 6%, diastolic BP +7 +/- 5%; phentolamine: RR -2 +/- 7%, MSNA -34 +/- 6%, systolic BP -16 +/- 8%, diastolic BP -13 +/- 4%, P < 0.05 except systolic BP, where P = 0.09). Thus LF variability is reduced when sympathetic activation is induced by alpha-adrenergic blockade. This suggests that alpha-adrenergic transmission within the baroreflex loop may contribute importantly to the predominance of LF cardiovascular variability associated with sympathetic excitation in humans.

  11. Abnormal neurocirculatory control during exercise in humans with chronic renal failure.

    PubMed

    Park, Jeanie; Middlekauff, Holly R

    2015-03-01

    Abnormal neurocirculatory control during exercise is one important mechanism leading to exercise intolerance in patients with both end-stage renal disease (ESRD) and earlier stages of chronic kidney disease (CKD). This review will provide an overview of mechanisms underlying abnormal neurocirculatory and hemodynamic responses to exercise in patients with kidney disease. Recent studies have shown that ESRD and CKD patients have an exaggerated increase in blood pressure (BP) during both isometric and rhythmic exercise. Subsequent studies examining the role of the exercise pressor reflex in the augmented pressor response revealed that muscle sympathetic nerve activity (MSNA) was not augmented during exercise in these patients, and metaboreflex-mediated increases in MSNA were blunted, while mechanoreflex-mediated increases were preserved under basal conditions. However, normalizing the augmented BP response during exercise via infusion of nitroprusside (NTP), and thereby equalizing baroreflex-mediated suppression of MSNA, an important modulator of the final hemodynamic response to exercise, revealed that CKD patients had an exaggerated increase in MSNA during isometric and rhythmic exercise. In addition, mechanoreflex-mediated control was augmented, and metaboreceptor blunting was no longer apparent in CKD patients with baroreflex normalization. Factors leading to mechanoreceptor sensitization, and other mechanisms underlying the exaggerated exercise pressor response, such as impaired functional sympatholysis, should be investigated in future studies.

  12. Phenylephrine-induced elevations in arterial blood pressure are attenuated in heat-stressed humans

    NASA Technical Reports Server (NTRS)

    Cui, Jian; Wilson, Thad E.; Crandall, Craig G.

    2002-01-01

    To test the hypothesis that phenylephrine-induced elevations in blood pressure are attenuated in heat-stressed humans, blood pressure was elevated via steady-state infusion of three doses of phenylephrine HCl in 10 healthy subjects in both normothermic and heat stress conditions. Whole body heating significantly increased sublingual temperature by 0.5 degrees C, muscle sympathetic nerve activity (MSNA), heart rate, and cardiac output and decreased total peripheral vascular resistance (TPR; all P < 0.005) but did not change mean arterial blood pressure (MAP; P > 0.05). At the highest dose of phenylephrine, the increase in MAP and TPR from predrug baselines was significantly attenuated during the heat stress [DeltaMAP 8.4 +/- 1.2 mmHg; DeltaTPR 0.96 +/- 0.85 peripheral resistance units (PRU)] compared with normothermia (DeltaMAP 15.4 +/- 1.4 mmHg, DeltaTPR 7.13 +/- 1.18 PRU; all P < 0.001). The sensitivity of baroreflex control of MSNA and heart rate, expressed as the slope of the relationship between MSNA and diastolic blood pressure, as well as the slope of the relationship between heart rate and systolic blood pressure, respectively, was similar between thermal conditions (each P > 0.05). These data suggest that phenylephrine-induced elevations in MAP are attenuated in heat-stressed humans without affecting baroreflex control of MSNA or heart rate.

  13. Vestibulosympathetic reflex during orthostatic challenge in aging humans

    NASA Technical Reports Server (NTRS)

    Monahan, Kevin D.; Ray, Chester A.

    2002-01-01

    Aging attenuates the increase in muscle sympathetic nerve activity (MSNA) and elicits hypotension during otolith organ engagement in humans. The purpose of the present study was to determine the neural and cardiovascular responses to otolithic engagement during orthostatic stress in older adults. We hypothesized that age-related impairments in the vestibulosympathetic reflex would persist during orthostatic challenge in older subjects and might compromise arterial blood pressure regulation. MSNA, arterial blood pressure, and heart rate responses to head-down rotation (HDR) performed with and without lower body negative pressure (LBNP) in prone subjects were measured. Ten young (27 +/- 1 yr) and 11 older subjects (64 +/- 1 yr) were studied prospectively. HDR performed alone elicited an attenuated increase in MSNA in older subjects (Delta106 +/- 28 vs. Delta20 +/- 7% for young and older subjects). HDR performed during simultaneous orthostatic stress increased total MSNA further in young (Delta53 +/- 15%; P < 0.05) but not older subjects (Delta-5 +/- 4%). Older subjects demonstrated consistent significant hypotension during HDR performed both alone (Delta-6 +/- 2 mmHg) and during LBNP (Delta-7 +/- 2 mmHg). These data provide experimental support for the concept that age-related impairments in the vestibulosympathetic reflex persist during orthostatic challenge in older adults. Furthermore, these findings are consistent with the concept that age-related alterations in vestibular function might contribute to altered orthostatic blood pressure regulation with age in humans.

  14. Effect of aerobic training on baroreflex regulation of cardiac and sympathetic function.

    PubMed

    Sheldahl, L M; Ebert, T J; Cox, B; Tristani, F E

    1994-01-01

    To investigate the effect of aerobic exercise training on baroreflex regulation of muscle sympathetic nerve activity (MSNA) and cardiac R-R intervals in a middle-aged to older population, 10 healthy men > 40 yr of age underwent tests of autonomic function before and after 12 wk of high-intensity training. Cardiac and peripheral baroslopes were determined from the R-R interval vs. mean arterial pressure (MAP) and peroneal MSNA vs. diastolic pressure relationships, respectively, during sequential bolus injections of nitroprusside and phenylephrine. Maximal oxygen uptake increased (P < 0.05) 17% with training. Resting R-R interval increased (881 +/- 23 to 956 +/- 38 ms, P < 0.05), MAP decreased (96 +/- 2 to 91 +/- 3 mmHg, P < 0.05), and MSNA was unaltered (23.1 +/- 2.3 to 23.6 +/- 1.9 bursts/min) with training. Before and after training, respectively, cardiac baroslopes determined with decreasing (8.7 +/- 0.9 to 9.9 +/- 5.5 ms/mmHg) and increasing MAP (9.6 +/- 2.1 to 9.9 +/- 2.2 ms/mmHg) and the peripheral sympathetic baroslope (-3.3 +/- 0.4 to -3.5 +/- 0.6 bursts.min-1 x mmHg-1) did not differ. The results suggest that short-term aerobic training does not alter resting MSNA or neurocirculatory responses to baroreceptor challenges in middle-aged and older men.

  15. Distension of central great vein decreases sympathetic outflow in humans.

    PubMed

    Cui, Jian; Gao, Zhaohui; Blaha, Cheryl; Herr, Michael D; Mast, Jessica; Sinoway, Lawrence I

    2013-08-01

    Classic canine studies suggest that central great vein distension evokes an autonomic reflex tachycardia (Bainbridge reflex). It is unclear whether central venous distension in humans is a necessary and sufficient stimulus to evoke a reflex increase in heart rate (HR), blood pressure (BP), and muscle sympathetic nerve activity (MSNA). Prior work from our laboratory suggests that limb venous distension evokes a reflex increase in BP and MSNA in humans. We hypothesized that in humans, compared with the limb venous distension, inferior vena cava (IVC) distension would evoke a less prominent increase in HR and MSNA. IVC distension (monitored with ultrasonography) was induced by two methods: 1) head-down tilt (HDT, N = 13); and 2) lower-body positive pressure (LBPP, N = 10). Two minutes of HDT induced IVC distension (Δ2.6 ± 0.2 mm, P < 0.001, ~27% in cross-sectional area), slightly increased mean BP (Δ2.3 ± 0.7 mmHg, P = 0.005), decreased MSNA (Δ5.2 ± 0.8 bursts/min, P < 0.001, N = 10), and did not alter HR (P = 0.37). LBPP induced similar IVC distension, increased BP (Δ2.0 ± 0.7 mmHg, P < 0.01), and did not alter HR (P = 0.34). Thus central venous distension leads to a rapid increase in BP and a subsequent fall in MSNA. Central venous distension does not evoke either bradycardia or tachycardia in humans. The absence of a baroreflex-mediated bradycardia suggests that the Bainbridge reflex is engaged. Clearly, this reflex differs from the powerful sympathoexcitation peripheral venous distension reflex described in humans.

  16. Attenuated cardiac baroreflex in men with presyncope evoked by lower body negative pressure.

    PubMed

    Wijeysundera, D N; Butler, G C; Ando, S; Pollard, M; Picton, P; Floras, J S

    2001-03-01

    Mechanisms responsible for presyncope during lower body negative pressure (LBNP) in otherwise healthy subjects are poorly understood. Muscle sympathetic nerve activity (MSNA), blood pressure, heart rate (HR), HR power spectra, central venous pressure (CVP) and stroke volume were determined in 14 healthy men subjected to incremental LBNP. Of these, seven experienced presyncope at LBNP >-15 mmHg. Subjects who tolerated LBNP >-15 mmHg had significantly lower CVP (2.6+/-1.0 versus 7.2+/-1.2 mmHg; means+/-S.E.M., P<0.02), HR (59+/-2 versus 66+/-3 beats/min, P<0.05) and MSNA burst frequency (29.0+/-2.4 versus 39.0+/-3.5 bursts/min, P<0.05) during supine rest. LBNP at -15 mmHg had no effect on blood pressure, but caused similar and significant reductions in stroke volume and cardiac output in both groups. Subjects who tolerated LBNP had significant reflex increases in HR, MSNA burst frequency and burst amplitude with LBNP of -15 mmHg. These responses were absent in those who experienced presyncope. The gain of the cardiac baroreflex regulation of MSNA was markedly attenuated in pre-syncopal subjects (1.2+/-0.6 versus 8.8+/-1.4 bursts/100 heart beats per mmHg; P<0.001). Healthy subjects who experience presyncope in response to LBNP appear more dependent, when supine, upon MSNA to maintain preload, and less able to increase sympathetic vasoconstrictor discharge to skeletal muscle reflexively in response to orthostatic stimuli.

  17. Active-R filter

    DOEpatents

    Soderstrand, Michael A.

    1976-01-01

    An operational amplifier-type active filter in which the only capacitor in the circuit is the compensating capacitance of the operational amplifiers, the various feedback and coupling elements being essentially solely resistive.

  18. Get Active

    MedlinePlus

    ... Basics: Health Benefits What are the benefits of physical activity? Physical activity increases your chances of living longer. ... pain Help you feel better about yourself Is physical activity for everyone? Yes! Physical activity is good for ...

  19. Simultaneous Characterization of Sympathetic and Cardiac Arms of the Baroreflex through Sequence Techniques during Incremental Head-Up Tilt

    PubMed Central

    Marchi, Andrea; Bari, Vlasta; De Maria, Beatrice; Esler, Murray; Lambert, Elisabeth; Baumert, Mathias; Porta, Alberto

    2016-01-01

    We propose a sympathetic baroreflex (sBR) sequence method for characterizing sBR from spontaneous beat-to-beat fluctuations of muscle sympathetic nerve activity (MSNA) and diastolic arterial pressure (DAP). The method exploits a previously defined MSNA variability quantifying the fluctuations of MSNA burst rate. The method is based on the detection of MSNA and DAP sequences characterized by the contemporaneous DAP increase and MSNA decrease or vice versa. The percentage of sBR sequences (SEQ%sBR) was taken as an indication of the degree of sBR solicitation and the average slope of the regression lines in the (DAP, MSNA) plane was taken as sBR sensitivity (sBRSSEQ) and expressed in bursts.s−1.mmHg−1. sBRSSEQ was compared to a more traditional estimate based on the baroreflex threshold analysis (sBRSBTA). An incremental head-up tilt protocol, carried out in 12 young healthy subjects (age: 20–36 yr, median = 22.5 yr, 9 females) sequentially tilted at 0, 20, 30, 40, 60° table inclinations, was utilized to set the sBR sequence method parameters. Traditional sequence analysis was exploited to estimate cardiac baroreflex (cBR) sensitivity (cBRSSEQ) and percentage of cBR sequences (SEQ%cBR). The head-up tilt induced the progressive increase of SEQ%sBR and SEQ%cBR and gradual decrease of both sBRSSEQ and cBRSSEQ, thus suggesting the gradual rise of the sBR and cBR solicitations and the progressive reduction of their effectiveness with the stimulus. sBRSSEQ was significantly associated with sBRSBTA. sBRSSEQ and cBRSSEQ were significantly correlated as well as SEQ%sBR and SEQ%cBR, even though the correlation was not strong, thus suggesting a certain degree of independence between the baroreflex arms. The proposed sBR sequence approach provides a dynamical characterization of the sBR alternative to more traditional static pharmacological and nonpharmacological methods and fully homogenous with the cBR sequence technique. PMID:27746741

  20. Contribution of perfusion pressure to vascular resistance response during head-up tilt

    NASA Technical Reports Server (NTRS)

    Imadojemu, V. A.; Lott, M. E.; Gleeson, K.; Hogeman, C. S.; Ray, C. A.; Sinoway, L. I.

    2001-01-01

    We measured brachial and femoral artery flow velocity in eight subjects and peroneal and median muscle sympathetic nerve activity (MSNA) in five subjects during tilt testing to 40 degrees. Tilt caused similar increases in MSNA in the peroneal and median nerves. Tilt caused a fall in femoral artery flow velocity, whereas no changes in flow velocity were seen in the brachial artery. Moreover, with tilt, the increase in the vascular resistance employed (blood pressure/flow velocity) was greater and more sustained in the leg than in the arm. The ratio of the percent increase in vascular resistance in leg to arm was 2.5:1. We suggest that the greater vascular resistance effects in the leg were due to an interaction between sympathetic nerve activity and the myogenic response.

  1. Arterial Pulse Pressure and Its Association With Reduced Stroke Volume During Progressive Central Hypovolemia

    DTIC Science & Technology

    2006-09-01

    NM, Joyner MJ. Influence of increased central venous pressure on baroreflex control of sympathetic activity in humans. Am J Physiol Heart Circ Physiol...Arterial Pulse Pressure and Its Association With Reduced Stroke Volume During Progressive Central Hypovolemia Victor A. Convertino, PhD, William H...reduction of SV and change in MSNA during graded central hypovolemia in humans. Methods: After a 12-minute baseline data collection period, 13 men were

  2. Aging attenuates the vestibulosympathetic reflex in humans

    NASA Technical Reports Server (NTRS)

    Ray, Chester A.; Monahan, Kevin D.

    2002-01-01

    BACKGROUND: The vestibular system contributes to sympathetic activation by engagement of the otolith organs. However, there is a significant loss of vestibular function with aging. Therefore, the purpose of the present study was to determine if young and older individuals differ in their cardiovascular and sympathetic responses to otolithic stimulation (ie, head-down rotation, HDR). We hypothesized that responses to otolithic stimulation would be attenuated in older adults because of morphological and physiological alterations that occur in the vestibular system with aging. METHODS AND RESULTS: Arterial blood pressure, heart rate, muscle sympathetic nerve activity (MSNA), and head rotation were measured during HDR in 11 young (26 +/- 1 years) and 11 older (64 +/- 1 years) subjects in the prone posture. Five older subjects performed head rotation (chin to chest) in the lateral decubitus position, which simulates HDR but does not alter afferent inputs from the vestibular system. MSNA responses to HDR were significantly attenuated in older as compared with young subjects (P<0.01). MSNA increased in the older subjects by only 12 +/- 5% as compared with 85 +/- 16% in the young. Furthermore, HDR elicited significant reductions in mean arterial blood pressure in older (Delta-6 +/- 1 mm Hg; P<0.01) but not young subjects (Delta1 +/- 1 mm Hg). In contrast to HDR, head rotation performed in the lateral decubitus position did not elicit hypotension. MSNA responses to baroreceptor unloading and the cold pressor test were not different between the age groups. CONCLUSIONS: These data indicate that aging attenuates the vestibulosympathetic reflex in humans and may contribute to the increased prevalence of orthostatic hypotension with age.

  3. Activation detector

    DOEpatents

    Bell, Zane William [Oak Ridge, TN; Boatner, Lynn Allen [Oak Ridge, TN

    2009-12-08

    A method of detecting an activator, the method including impinging with an activator a receptor material lacking a photoluminescent material and generating a by-product of a radioactive decay due to the activator impinging the reeptor material. The method further including, generating light from the by-product via the Cherenkov effect and identifying a characteristic of the activator based on the light.

  4. Comparison of sympathetic nerve responses to neck and forearm isometric exercise

    NASA Technical Reports Server (NTRS)

    Steele, S. L. Jr; Ray, C. A.

    2000-01-01

    PURPOSE: Although the autonomic and cardiovascular responses to arm and leg exercise have been studied, the sympathetic adjustments to exercise of the neck have not. The purpose of the present study was twofold: 1) to determine sympathetic and cardiovascular responses to isometric contractions of the neck extensors and 2) to compare sympathetic and cardiovascular responses to isometric exercise of the neck and forearm. METHODS: Muscle sympathetic nerve activity (MSNA), mean arterial pressure (MAP), and heart rate were measured in nine healthy subjects while performing isometric neck extension (INE) and isometric handgrip (IHG) in the prone position. After a 3-min baseline period, subjects performed three intensities of INE for 2.5 min each: 1) unloaded (supporting head alone), 2) 10% maximal voluntary contraction (MVC), and 3) 30% MVC, then subjects performed two intensities (10% and 30% MVC) of IHG for 2.5 min. RESULTS: Supporting the head by itself did not significantly change any of the variables. During [NE, MAP significantly increased by 10 +/- 2 and 31 +/- 4 mm Hg and MSNA increased by 67 +/- 46 and 168 +/- 36 units/30 s for 10% and 30% MVC, respectively. IHG and INE evoked similar responses at 10% MVC, but IHG elicited higher peak MAP and MSNA at 30% MVC (37 +/- 7 mm Hg (P < 0.05) and 300 +/- 48 units/30 s (P < 0.01) for IHG, respectively). CONCLUSIONS: The data indicate that INE can elicit marked increases in MSNA and cardiovascular responses but that it evokes lower peak responses as compared to IHG. We speculate that possible differences in muscle fiber type composition, muscle mass, and/or muscle architecture of the neck and forearm are responsible for these differences in peak responses.

  5. Chronic orthostatic intolerance: a disorder with discordant cardiac and vascular sympathetic control

    NASA Technical Reports Server (NTRS)

    Furlan, R.; Jacob, G.; Snell, M.; Robertson, D.; Porta, A.; Harris, P.; Mosqueda-Garcia, R.

    1998-01-01

    BACKGROUND: Chronic orthostatic intolerance (COI) is a debilitating autonomic condition in young adults. Its neurohumoral and hemodynamic profiles suggest possible alterations of postural sympathetic function and of baroreflex control of heart rate (HR). METHODS AND RESULTS: In 16 COI patients and 16 healthy volunteers, intra-arterial blood pressure (BP), ECG, central venous pressure (CVP), and muscle sympathetic nerve activity (MSNA) were recorded at rest and during 75 degrees tilt. Spectral analysis of RR interval and systolic arterial pressure (SAP) variabilities provided indices of sympathovagal modulation of the sinoatrial node (ratio of low-frequency to high-frequency components, LF/HF) and of sympathetic vasomotor control (LFSAP). Baroreflex mechanisms were assessed (1) by the slope of the regression line obtained from changes of RR interval and MSNA evoked by pharmacologically induced alterations in BP and (2) by the index alpha, obtained from cross-spectral analysis of RR and SAP variabilities. At rest, HR, MSNA, LF/HF, and LFSAP were higher in COI patients, whereas BP and CVP were similar in the two groups. During tilt, BP did not change and CVP fell by the same extent in the 2 groups; the increase of HR and LF/HF was more pronounced in COI patients. Conversely, the increase of MSNA was lower in COI than in control subjects. Baroreflex sensitivity was similar in COI and control subjects at rest; tilt reduced alpha similarly in both groups. CONCLUSIONS: COI is characterized by an overall enhancement of noradrenergic tone at rest and by a blunted postganglionic sympathetic response to standing, with a compensatory cardiac sympathetic overactivity. Baroreflex mechanisms maintain their functional responsiveness. These data suggest that in COI, the functional distribution of central sympathetic tone to the heart and vasculature is abnormal.

  6. Obstructive apnea during sleep is associated with peripheral vasoconstriction

    NASA Technical Reports Server (NTRS)

    Imadojemu, Virginia A.; Gleeson, Kevin; Gray, Kristen S.; Sinoway, Lawrence I.; Leuenberger, Urs A.

    2002-01-01

    Obstructive apnea during sleep is associated with a substantial transient blood pressure elevation. The mechanism of this pressor response is unclear. In this study we measured muscle sympathetic nerve activity (MSNA), mean arterial pressure (Psa), and mean limb blood velocity as an index of blood flow (MBV, Doppler) and calculated changes in limb vascular resistance during and after apneas during both wakefulness and sleep in patients with the obstructive sleep apnea syndrome. Immediately postapnea during sleep Psa increased significantly compared with the earlier stages of apnea and this was preceded by a rise of MSNA (n = 5). In contrast to blood pressure, MBV remained unchanged. Because resistance = blood pressure/blood flow, limb vascular resistance increased by 29 +/- 8% from late apnea to postapnea (n = 7, p < 0.002). Voluntary breathhold maneuvers during room air exposure evoked similar responses (n = 10). Supplemental oxygen administered via nonrebreather face mask attenuated the MSNA and vasoconstrictor responses to obstructive (n = 2) and voluntary apneas (n = 10). Our data suggest that obstructive apneas in patients with the obstructive apnea syndrome are accompanied by transient limb vasoconstriction. This vasoconstrictor response appears to be, at least in part, mediated by the sympathetic nervous system and may be linked to hypoxia.

  7. Conditional symbolic analysis detects nonlinear influences of respiration on cardiovascular control in humans

    PubMed Central

    Porta, Alberto; Marchi, Andrea; Bari, Vlasta; Heusser, Karsten; Tank, Jens; Jordan, Jens; Barbic, Franca; Furlan, Raffaello

    2015-01-01

    We propose a symbolic analysis framework for the quantitative characterization of complex dynamical systems. It allows the description of the time course of a single variable, the assessment of joint interactions and an analysis triggered by a conditioning input. The framework was applied to spontaneous variability of heart period (HP), systolic arterial pressure (SAP) and integrated muscle sympathetic nerve activity (MSNA) with the aim of characterizing cardiovascular control and nonlinear influences of respiration at rest in supine position, during orthostatic challenge induced by 80° head-up tilt (TILT) and about 3 min before evoked pre-syncope signs (PRESY). The approach detected (i) the exaggerated sympathetic modulation and vagal withdrawal from HP variability and the increased presence of fast MSNA variability components during PRESY compared with TILT; (ii) the increase of the SAP–HP coordination occurring at slow temporal scales and a decrease of that occurring at faster time scales during PRESY compared with TILT; (iii) the reduction of the coordination between fast MSNA and SAP patterns during TILT and PRESY; (iv) the nonlinear influences of respiration leading to an increased likelihood to observe the abovementioned findings during expiration compared with inspiration one. The framework provided simple, quantitative indexes able to distinguish experimental conditions characterized by different states of the autonomic nervous system and to detect the early signs of a life threatening situation such as postural syncope. PMID:25548269

  8. Sympathetic discharge and vascular resistance after bed rest

    NASA Technical Reports Server (NTRS)

    Shoemaker, J. K.; Hogeman, C. S.; Leuenberger, U. A.; Herr, M. D.; Gray, K.; Silber, D. H.; Sinoway, L. I.

    1998-01-01

    The effect of -6 degrees head-down-tilt bed rest (HDBR) for 14 days on supine sympathetic discharge and cardiovascular hemodynamics at rest was assessed. Mean arterial pressure, heart rate (n = 25), muscle sympathetic nerve activity (MSNA; n = 16) burst frequency, and forearm blood flow (n = 14) were measured, and forearm vascular resistance (FVR) was calculated. Stroke distance, our index of stroke volume, was derived from measurements of aortic mean blood velocity (Doppler) and R-R interval (n = 7). With these data, an index of total peripheral resistance was determined. Heart rate at rest was greater in the post (71 +/- 2 beats/min)- compared with the pre-HDBR test (66 +/- 2 beats/min; P < 0.003), but mean arterial pressure was unchanged. Aortic stroke distance during post-HDBR (15.5 +/- 1.1 cm/beat) was reduced from pre-HDBR levels (20.0 +/- 1.5 cm/beat) (P < 0.03). Also, MSNA burst frequency was reduced in the post (16.7 +/- 2.8 beats/min)- compared with the pre (25.2 +/- 2.6 beats/min)-HDBR condition (P < 0.01). Bed rest did not alter forearm blood flow, FVR, or total peripheral resistance. Thus reductions in MSNA with HDBR were not associated with a decrease in FVR.

  9. Increased expression of HCN2 channel protein in L4 dorsal root ganglion neurons following axotomy of L5- and inflammation of L4-spinal nerves in rats.

    PubMed

    Smith, T; Al Otaibi, M; Sathish, J; Djouhri, L

    2015-06-04

    A hallmark of peripheral neuropathic pain (PNP) is chronic spontaneous pain and/or hypersensitivity to normally painful stimuli (hyperalgesia) or normally nonpainful stimuli (allodynia).This pain results partly from abnormal hyperexcitability of dorsal root ganglion (DRG) neurons. We have previously shown, using a modified version of the lumbar 5 (L5)-spinal nerve ligation model of PNP (mSNA model involving L5-spinal nerve axotomy plus loose ligation of the lumbar 4 (L4)-spinal nerve with neuroinflammation-inducing chromic-gut), that L4 DRG neurons exhibit increased spontaneous activity, the key characteristic of neuronal hyperexcitability. The underlying ionic and molecular mechanisms of the hyperexcitability of L4 DRG neurons are incompletely understood, but could result from changes in expression and/or function of ion channels including hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which are active near the neuron's resting membrane potential, and which produce an excitatory inward current that depolarizes the membrane potential toward the threshold of action potential generation. Therefore, in the present study we used the mSNA model to investigate whether: (a) expression of HCN1-HCN3 channels is altered in L4 DRG neurons which, in the mSNA model, are essential for transmission of the evoked pain, and which contribute to chronic spontaneous pain, and (b) local (intraplantar) blockade of these HCN channels, with a specific blocker, ZD7288, attenuates chronic spontaneous pain and/or evoked pain in mSNA rats. We found 7days after mSNA: (1) a significant increase in HCN2-immunoreactivity in small (<30μm) DRG neurons (predominantly IB4-negative neurons), and in the proportion of small neurons expressing HCN2 (putative nociceptors); (2) no significant change in HCN1- or HCN3-immunoreactivity in all cell types; and (3) attenuation, with ZD7288 (100μM intraplantar), of chronic spontaneous pain behavior (spontaneous foot lifting) and mechanical

  10. Catalyst activator

    DOEpatents

    McAdon, Mark H.; Nickias, Peter N.; Marks, Tobin J.; Schwartz, David J.

    2001-01-01

    A catalyst activator particularly adapted for use in the activation of metal complexes of metals of Group 3-10 for polymerization of ethylenically unsaturated polymerizable monomers, especially olefins, comprising two Group 13 metal or metalloid atoms and a ligand structure including at least one bridging group connecting ligands on the two Group 13 metal or metalloid atoms.

  11. Outdoor Activities.

    ERIC Educational Resources Information Center

    Minneapolis Independent School District 275, Minn.

    Twenty-four activities suitable for outdoor use by elementary school children are outlined. Activities designed to make children aware of their environment include soil painting, burr collecting, insect and pond water collecting, studies of insect galls and field mice, succession studies, and a model of natural selection using dyed toothpicks. A…

  12. Physical activity

    MedlinePlus

    ... activity -- which includes an active lifestyle and routine exercise -- plus eating well, is the best way to stay healthy. ... goal. Your goal might be to: Manage a health condition Reduce stress ... other benefits, such as: Better control of your weight and ...

  13. Astronomy Activities.

    ERIC Educational Resources Information Center

    Greenstone, Sid

    This document consists of activities and references for teaching astronomy. The activities (which include objectives, list of materials needed, and procedures) focus on: observing the Big Dipper and locating the North Star; examining the Big Dipper's stars; making and using an astrolabe; examining retograde motion of Mars; measuring the Sun's…

  14. Cardiovascular and sympathetic neural responses to handgrip and cold pressor stimuli in humans before, during and after spaceflight

    NASA Technical Reports Server (NTRS)

    Fu, Qi; Levine, Benjamin D.; Pawelczyk, James A.; Ertl, Andrew C.; Diedrich, Andre; Cox, James F.; Zuckerman, Julie H.; Ray, Chester A.; Smith, Michael L.; Iwase, Satoshi; Saito, Mitsuru; Sugiyama, Yoshiki; Mano, Tadaaki; Zhang, Rong; Iwasaki, Kenichi; Lane, Lynda D.; Buckey, Jay C Jr; Cooke, William H.; Robertson, Rose Marie; Baisch, Friedhelm J.; Blomqvist, C. Gunnar; Eckberg, Dwain L.; Robertson, David; Biaggioni, Italo

    2002-01-01

    Astronauts returning to Earth have reduced orthostatic tolerance and exercise capacity. Alterations in autonomic nervous system and neuromuscular function after spaceflight might contribute to this problem. In this study, we tested the hypothesis that exposure to microgravity impairs autonomic neural control of sympathetic outflow in response to peripheral afferent stimulation produced by handgrip and a cold pressor test in humans. We studied five astronauts approximately 72 and 23 days before, and on landing day after the 16 day Neurolab (STS-90) space shuttle mission, and four of the astronauts during flight (day 12 or 13). Heart rate, arterial pressure and peroneal muscle sympathetic nerve activity (MSNA) were recorded before and during static handgrip sustained to fatigue at 40 % of maximum voluntary contraction, followed by 2 min of circulatory arrest pre-, in- and post-flight. The cold pressor test was applied only before (five astronauts) and during flight (day 12 or 13, four astronauts). Mean (+/- S.E.M.) baseline heart rates and arterial pressures were similar among pre-, in- and post-flight measurements. At the same relative fatiguing force, the peak systolic pressure and mean arterial pressure during static handgrip were not different before, during and after spaceflight. The peak diastolic pressure tended to be higher post- than pre-flight (112 +/- 6 vs. 99 +/- 5 mmHg, P = 0.088). Contraction-induced rises in heart rate were similar pre-, in- and post-flight. MSNA was higher post-flight in all subjects before static handgrip (26 +/- 4 post- vs. 15 +/- 4 bursts min(-1) pre-flight, P = 0.017). Contraction-evoked peak MSNA responses were not different before, during, and after spaceflight (41 +/- 4, 38 +/- 5 and 46 +/- 6 bursts min(-1), all P > 0.05). MSNA during post-handgrip circulatory arrest was higher post- than pre- or in-flight (41 +/- 1 vs. 33 +/- 3 and 30 +/- 5 bursts min(-1), P = 0.038 and 0.036). Similarly, responses of MSNA and blood pressure

  15. Activated Charcoal

    MedlinePlus

    ... is used to treat poisonings, reduce intestinal gas (flatulence), lower cholesterol levels, prevent hangover, and treat bile ... lower cholesterol levels in the blood. Decreasing gas (flatulence). Some studies show that activated charcoal is effective ...

  16. Activity Theory.

    ERIC Educational Resources Information Center

    Koschmann, Timothy; Roschelle, Jeremy; Nardi, Bonnie A.

    1998-01-01

    Includes three articles that discuss activity theory, based on "Context and Consciousness." Topics include human-computer interaction; computer interfaces; hierarchical structuring; mediation; contradictions and development; failure analysis; and designing educational technology. (LRW)

  17. Plant metacaspase activation and activity.

    PubMed

    Minina, Elena A; Stael, Simon; Van Breusegem, Frank; Bozhkov, Peter V

    2014-01-01

    Metacaspases are essential for cell death regulation in plants. Further understanding of biochemistry of metacaspases and their molecular function in plant biology requires a set of robust methods for detection of metacaspase activation and quantitative analysis of corresponding proteolytic activity. Here we describe methods for purification of recombinant metacaspases, measurement of enzymatic activity of recombinant and endogenous metacaspases in vitro and in cell lysates, respectively, and finally detection of metacaspase activation in vivo. Additionally, an in vitro metacaspase protein substrate cleavage assay based on the cell-free production of substrate protein followed by proteolysis with recombinant metacaspase is presented. These methods have been originally developed for type II metacaspases from Arabidopsis and Norway spruce (Picea abies), but they can be used as templates for type I metacaspases, as well as for type II metacaspases from other species.

  18. Active colloids

    NASA Astrophysics Data System (ADS)

    Aranson, Igor S.

    2013-01-01

    A colloidal suspension is a heterogeneous fluid containing solid microscopic particles. Colloids play an important role in our everyday life, from food and pharmaceutical industries to medicine and nanotechnology. It is useful to distinguish two major classes of colloidal suspensions: equilibrium and active, i.e., maintained out of thermodynamic equilibrium by external electric or magnetic fields, light, chemical reactions, or hydrodynamic shear flow. While the properties of equilibrium colloidal suspensions are fairly well understood, active colloids pose a formidable challenge, and the research is in its early exploratory stage. One of the most remarkable properties of active colloids is the possibility of dynamic self-assembly, a natural tendency of simple building blocks to organize into complex functional architectures. Examples range from tunable, self-healing colloidal crystals and membranes to self-assembled microswimmers and robots. Active colloidal suspensions may exhibit material properties not present in their equilibrium counterparts, e.g., reduced viscosity and enhanced self-diffusivity, etc. This study surveys the most recent developments in the physics of active colloids, both in synthetic and living systems, with the aim of elucidation of the fundamental physical mechanisms governing self-assembly and collective behavior.

  19. Active microwaves

    NASA Technical Reports Server (NTRS)

    Evans, D.; Vidal-Madjar, D.

    1994-01-01

    Research on the use of active microwaves in remote sensing, presented during plenary and poster sessions, is summarized. The main highlights are: calibration techniques are well understood; innovative modeling approaches have been developed which increase active microwave applications (segmentation prior to model inversion, use of ERS-1 scatterometer, simulations); polarization angle and frequency diversity improves characterization of ice sheets, vegetation, and determination of soil moisture (X band sensor study); SAR (Synthetic Aperture Radar) interferometry potential is emerging; use of multiple sensors/extended spectral signatures is important (increase emphasis).

  20. Activated Sludge.

    ERIC Educational Resources Information Center

    Saunders, F. Michael

    1978-01-01

    Presents the 1978 literature review of wastewater treatment. This review covers: (1) activated sludge process; (2) process control; (3) oxygen uptake and transfer; (4) phosphorus removal; (5) nitrification; (6) industrial wastewater; and (7) aerobic digestion. A list of 136 references is also presented. (HM)

  1. Activities: Spirolaterals.

    ERIC Educational Resources Information Center

    Brannan, Richard; McFadden, Scott

    1981-01-01

    A set of activities designed to help students discover properties about order-3 spirolaterals on square grid paper is presented. The materials are prepared on worksheets designed for easy duplication. The lessons can lead to investigations involving spirolaterals of many other orders and shapes. (MP)

  2. Leaf Activities.

    ERIC Educational Resources Information Center

    Mingie, Walter

    Leaf activities can provide a means of using basic concepts of outdoor education to learn in elementary level subject areas. Equipment needed includes leaves, a clipboard with paper, and a pencil. A bag of leaves may be brought into the classroom if weather conditions or time do not permit going outdoors. Each student should pick a leaf, examine…

  3. Learning Activities.

    ERIC Educational Resources Information Center

    Tipton, Tom, Ed.

    1983-01-01

    Presents a flow chart for naming inorganic compounds. Although it is not necessary for students to memorize rules, preliminary skills needed before using the chart are outlined. Also presents an activity in which the mass of an imaginary atom is determined using lead shot, Petri dishes, and a platform balance. (JN)

  4. Activity report

    SciTech Connect

    Yu, S W

    2008-08-11

    This report is aimed to show the author's activities to support the LDRD. The title is 'Investigation of the Double-C Behavior in the Pu-Ga Time-Temperature-Transformation Diagram' The sections are: (1) Sample Holder Test; (2) Calculation of x-ray diffraction patterns; (3) Literature search and preparing publications; (4) Tasks Required for APS Experiments; and (5) Communications.

  5. Antimicrobial Activity.

    PubMed

    2016-01-01

    Natural products of higher plants may possess a new source of antimicrobial agents with possibly novel mechanisms of action. They are effective in the treatment of infectious diseases while simultaneously mitigating many of the side effects that are often associated with conventional antimicrobials. A method using scanning electron microscope (SEM) to study the morphology of the bacterial and fungal microbes and thus determining antimicrobial activity is presented in the chapter.

  6. Analgesic Activity.

    PubMed

    2016-01-01

    Analgesics are agents which selectively relieve pain by acting in the CNS and peripheral pain mediators without changing consciousness. Analgesics may be narcotic or non-narcotic. The study of pain in animals raises ethical, philosophical, and technical problems. Both peripheral and central pain models are included to make the test more evident for the analgesic property of the plant. This chapter highlights methods such as hot plate and formalin and acetic acid-induced pain models to check the analgesic activity of medicinal plants.

  7. Active packaging with antifungal activities.

    PubMed

    Nguyen Van Long, N; Joly, Catherine; Dantigny, Philippe

    2016-03-02

    There have been many reviews concerned with antimicrobial food packaging, and with the use of antifungal compounds, but none provided an exhaustive picture of the applications of active packaging to control fungal spoilage. Very recently, many studies have been done in these fields, therefore it is timely to review this topic. This article examines the effects of essential oils, preservatives, natural products, chemical fungicides, nanoparticles coated to different films, and chitosan in vitro on the growth of moulds, but also in vivo on the mould free shelf-life of bread, cheese, and fresh fruits and vegetables. A short section is also dedicated to yeasts. All the applications are described from a microbiological point of view, and these were sorted depending on the name of the species. Methods and results obtained are discussed. Essential oils and preservatives were ranked by increased efficacy on mould growth. For all the tested molecules, Penicillium species were shown more sensitive than Aspergillus species. However, comparison between the results was difficult because it appeared that the efficiency of active packaging depended greatly on the environmental factors of food such as water activity, pH, temperature, NaCl concentration, the nature, the size, and the mode of application of the films, in addition to the fact that the amount of released antifungal compounds was not constant with time.

  8. Active tectonics

    SciTech Connect

    Not Available

    1986-01-01

    This study is part of a series of Studies in Geophysics that have been undertaken for the Geophysics Research Forum by the Geophysics Study Committee. One purpose of each study is to provide assessments from the scientific community to aid policymakers in decisions on societal problems that involve geophysics. An important part of such assessments is an evaluation of the adequacy of current geophysical knowledge and the appropriateness of current research programs as a source of information required for those decisions. The study addresses our current scientific understanding of active tectonics --- particularly the patterns and rates of ongoing tectonic processes. Many of these processes cannot be described reasonably using the limited instrumental or historical records; however, most can be described adequately for practical purposes using the geologic record of the past 500,000 years. A program of fundamental research focusing especially on Quaternary tectonic geology and geomorphology, paleoseismology, neotectonics, and geodesy is recommended to better understand ongoing, active tectonic processes. This volume contains 16 papers. Individual papers are indexed separately on the Energy Database.

  9. IASS Activity

    NASA Astrophysics Data System (ADS)

    Hojaev, Alisher S.; Ibragimova, Elvira M.

    2015-08-01

    It’s well known, astronomy in Uzbekistan has ancient roots and traditions (e.g., Mirzo Ulugh Beg, Abū al-Rayhān al-Bīrūnī, Abū ‘Abdallāh al-Khwārizmī) and astronomical heritage carefully preserved. Nowadays uzbek astronomers play a key role in scientific research but also in OAD and Decadal Plan activity in the Central Asia region. International Aerospace School (IASS) is an amazing and wonderful event held annually about 30 years. IASS is unique project in the region, and at the beginning we spent the Summer and Winter Schools. At present in the summer camp we gather about 50 teenage and undergraduate students over the country and abroad (France, Malaysia, Turkey, Azerbaijan, Pakistan, Russia, etc.). They are selected on the basis of tests of astronomy and space issues. During two weeks of IASS camp the invited scientists, cosmonauts and astronauts as well as other specialists give lectures and engage in practical exercises with IASS students in astronomy, including daily observations of the Sun and night sky observations with meniscus telescope, space research and exploration, aerospace modelling, preparation and presentation of original projects. This is important that IASS gives not theoretical grounds only but also practically train the students and the hands-on training is the major aims of IASS. Lectures and practice in the field of astronomy carried out with the direct involvement and generous assistance of Uranoscope Association (Paris, France). The current 26-th IASS is planned to held in July 2015.

  10. Physical Activity (Exercise)

    MedlinePlus

    ... Physical activity (exercise) fact sheet ePublications Physical activity (exercise) fact sheet How can physical activity improve my ... recent hip surgery More information on physical activity (exercise) For more information about physical activity (exercise), call ...

  11. Activation Energy

    NASA Technical Reports Server (NTRS)

    Gadeken, Owen

    2002-01-01

    Teaming is so common in today's project management environment that most of us assume it comes naturally. We further assume that when presented with meaningful and challenging work, project teams will naturally engage in productive activity to complete their tasks. This assumption is expressed in the simple (but false) equation: Team + Work = Teamwork. Although this equation appears simple and straightforward, it is far from true for most project organizations whose reality is a complex web of institutional norms based on individual achievement and rewards. This is illustrated by the very first successful team experience from my early Air Force career. As a young lieutenant, I was sent to Squadron Officer School, which was the first in the series of Air Force professional military education courses I was required to complete during my career. We were immediately formed into teams of twelve officers. Much of the course featured competition between these teams. As the most junior member of my team, I quickly observed the tremendous pressure to show individual leadership capability. At one point early in the course, almost everyone in our group was vying to become the team leader. This conflict was so intense that it caused us to fail miserably in our first outdoor team building exercise. We spent so much time fighting over leadership that we were unable to complete any of the events on the outdoor obstacle course. This complete lack of success was so disheartening to me that I gave our team little hope for future success. What followed was a very intense period of bickering, conflict, and even shouting matches as our dysfunctional team tried to cope with our early failures and find some way to succeed. British physician and researcher Wilfred Bion (Experiences in Groups, 1961) discovered that there are powerful psychological forces inherent in all groups that divert from accomplishing their primary tasks. To overcome these restraining forces and use the potential

  12. Staying Active: Physical Activity and Exercise

    MedlinePlus

    ... How much physical activity should I do each week? The Centers for Disease Control and Prevention recommend ... 150 minutes of moderate-intensity aerobic activity a week, along with muscle-strengthening activities on 2 days ...

  13. Exaggerated sympathetic and pressor responses to handgrip exercise in older hypertensive humans: role of the muscle metaboreflex.

    PubMed

    Delaney, Erin P; Greaney, Jody L; Edwards, David G; Rose, William C; Fadel, Paul J; Farquhar, William B

    2010-11-01

    Recent animal studies have reported that exercise pressor reflex (EPR)-mediated increases in blood pressure are exaggerated in hypertensive (HTN) rodents. Whether these findings can be extended to human hypertension remains unclear. Mean arterial pressure (MAP), muscle sympathetic nerve activity (MSNA), and venous metabolites were measured in normotensive (NTN; n = 23; 60 ± 1 yr) and HTN (n = 15; 63 ± 1 yr) subjects at baseline, and during static handgrip at 30 and 40% maximal voluntary contraction (MVC) followed by a period of postexercise ischemia (PEI) to isolate the metabolic component of the EPR. Changes in MAP from baseline were augmented in HTN subjects during both 30 and 40% MVC handgrip (P < 0.05 for both), and these group differences were maintained during PEI (30% PEI trial: Δ15 ± 2 NTN vs. Δ19 ± 2 HTN mmHg; 40% PEI trial: Δ16 ± 1 NTN vs. Δ23 ± 2 HTN mmHg; P < 0.05 for both). Similarly, in HTN subjects, MSNA burst frequency was greater during 30 and 40% MVC handgrip (P < 0.05 for both), and these differences were maintained during PEI [30% PEI trial: 35 ± 2 (NTN) vs. 44 ± 2 (HTN) bursts/min; 40% PEI trial: 36 ± 2 (NTN) vs. 48 ± 2 (HTN) bursts/min; P < 0.05 for both]. No group differences in metabolites were observed. MAP and MSNA responses to a cold pressor test were not different between groups, suggesting no group differences in generalized sympathetic responsiveness. In summary, compared with NTN subjects, HTN adults exhibit exaggerated sympathetic and pressor responses to handgrip exercise that are maintained during PEI, indicating that activation of the metabolic component of the EPR is augmented in older HTN humans.

  14. Association between resting-state brain functional connectivity and muscle sympathetic burst incidence

    PubMed Central

    Kucyi, Aaron; Millar, Philip J.; Murai, Hisayoshi; Kimmerly, Derek S.; Morris, Beverley L.; Bradley, T. Douglas; Floras, John S.

    2015-01-01

    The insula (IC) and cingulate are key components of the central autonomic network and central nodes of the salience network (SN), a set of spatially distinct but temporally correlated brain regions identified with resting-state (task free) functional MRI (rsMRI). To examine the SN's involvement in sympathetic outflow, we tested the hypothesis that individual differences in intrinsic connectivity of the SN correlate positively with resting postganglionic muscle sympathetic nerve activity (MSNA) burst incidence (BI) in subjects without and with obstructive sleep apnea (OSA). Overnight polysomnography, 5-min rsMRI, and fibular MSNA recording were performed in 36 subjects (mean age 57 yr; 10 women, 26 men). Independent component analysis (ICA) of the entire cohort identified the SN as including bilateral IC, pregenual anterior cingulate cortex (pgACC), midcingulate cortex (MCC), and the temporoparietal junction (TPJ). There was a positive correlation between BI and the apnea-hypopnea index (AHI) (P < 0.001), but dual-regression analysis identified no differences in SN functional connectivity between subjects with no or mild OSA (n = 17) and moderate or severe (n = 19) OSA. Correlation analysis relating BI to the strength of connectivity within the SN revealed large (i.e., spatial extent) and strong correlations for the left IC (P < 0.001), right pgACC/MCC (P < 0.006), left TPJ (P < 0.004), thalamus (P < 0.035), and cerebellum (P < 0.013). Indexes of sleep apnea were unrelated to BI and the strength of SN connectivity. There were no relationships between BI and default or sensorimotor network connectivity. This study links connectivity within the SN to MSNA, demonstrating several of its nodes to be key sympathoexcitatory regions. PMID:26538607

  15. Tactile stimulation of the oropharynx elicits sympathoexcitation in conscious humans

    PubMed Central

    Muller, Matthew D.; Mast, Jessica L.; Cui, Jian; Heffernan, Matthew J.; McQuillan, Patrick M.

    2013-01-01

    Tactile stimulation of the oropharynx (TSO) elicits the gag reflex and increases heart rate (HR) and mean arterial pressure (MAP) in anesthetized patients. However, the interaction between upper-airway defense reflexes and the sympathetic nervous system has not been investigated in conscious humans. In Experiment 1, beat-by-beat measurements of HR, MAP, muscle sympathetic nerve activity (MSNA), and renal vascular resistance (RVR) were measured during TSO and tactile stimulation of the hard palate (Sham) in the supine posture. In Experiment 2, TSO was performed before (pre) and after (post) inhalation of 4% lidocaine via nebulizer. Rate pressure product (RPP) was determined. Compared with Sham, TSO elicited the gag reflex and increased RPP [absolute change (Δ)36 ± 6 vs. 17 ± 5%], MSNA (Δ122 ± 39 vs. 19 ± 19%), and RVR (Δ55 ± 11 vs. 4 ± 4%). This effect occurred within one to two cardiac cycles of TSO. The ΔMAP (12 ± 3 vs. 6 ± 1 mmHg) and the ΔHR (10 ± 3 vs. 3 ± 3 beats/min) were also greater following TSO compared with Sham. Lidocaine inhalation blocked the gag reflex and attenuated increases in MAP (Δpre: 16 ± 2; Δpost: 5 ± 2 mmHg) and HR (Δpre: 12 ± 3; Δpost: 2 ± 2 beats/min) in response to TSO. When mechanically stimulated, afferents in the oropharynx not only serve to protect the airway but also cause reflex increases in MSNA, RVR, MAP, and HR. An augmented sympathoexcitatory response during intubation and laryngoscopy may contribute to perioperative cardiovascular morbidity and mortality. PMID:23599399

  16. Adolescent sexual activity.

    PubMed

    Braverman, P K; Strasburger, V C

    1993-11-01

    Adolescents are becoming sexually active at younger ages. One half of the adolescents in the United States are sexually active. This article reviews adolescent sexual activity, including rates of sexual activity, sexual practices, gay and lesbian youth, and factors affecting the initiation of sexual activity. In addition, adolescent pregnancy, with possible outcomes and effects on teen parents and their offspring, is discussed.

  17. Guide to Physical Activity

    MedlinePlus

    ... Families ( We Can! ) Health Professional Resources Guide to Physical Activity Physical activity is an important part of your ... to injury. Examples of moderate-intensity amounts of physical activity Common Chores Washing and waxing a car for ...

  18. Physical Activity Assessment

    Cancer.gov

    Current evidence convincingly indicates that physical activity reduces the risk of colon and breast cancer. Physical activity may also reduce risk of prostate cancer. Scientists are also evaluating potential relationships between physical activity and other cancers.

  19. Cortical regions associated with orthostatic stress in conscious humans

    NASA Astrophysics Data System (ADS)

    Kimmerly, Derek S.; O'Leary, Debbie D.; Cechetto, Angela; Shoemaker, Kevin J.

    2005-08-01

    The purpose of this study was to determine the cortical structures associated with lower body negative pressure (LBNP)-induced baroreflex control using functional magnetic resonance imaging (fMRI). Heart rate (HR) and LBNP were simultaneously monitored during scanning. Central venous pressure (CVP), muscle sympathetic nerve activity (MSNA) and arterial blood pressure (ABP) were measured on a separate day. Random effects analyses (SPM2) were used to evaluate fMRI signal changes that correlated separately with both LBNP and HR (15 and 35-mmHg versus 5-mmHg LBNP). LBNP at 15- and 35-mmHg decreased CVP and increased MSNA, both P < 0.05 versus baseline) but only LBNP at 35- mmHg elevated HR. ABP was similar at all levels of LBNP . Cortical regions demonstrating increased activity at higher HR and greater LBNP included the right superior posterior insula and the cerebellum. Conversely, bilateral anterior insular cortices, the right anterior cingulate, amygdala, and mediodorsal nucleus of the thalamus showed decreased neural activation.

  20. Political activity for physical activity: health advocacy for active transport

    PubMed Central

    2011-01-01

    Effective health advocacy is a priority for efforts to increase population participation in physical activity. Local councils are an important audience for this advocacy. The aim of the current study was to describe features of advocacy for active transport via submissions to city council annual plans in New Zealand, and the impact of an information sheet to encourage the health sector to be involved in this process. Written submissions to city council's annual consultation process were requested for 16 city councils over the period of three years (2007/08, 2008/09, and 2009/10). Submissions were reviewed and categories of responses were created. An advocacy information sheet encouraging health sector participation and summarising some of the evidence-base related to physical activity, active transport and health was released just prior to the 2009/10 submission time. Over the period of the study, city councils received 47,392 submissions, 17% of which were related to active transport. Most submissions came from city residents, with a small proportion (2%) from the health sector. The largest category of submissions was in support of pedestrian and cycling infrastructure, design and maintenance of facilities and additional features to support use of these transport modes. Health arguments featured prominently in justifications for active transport initiatives, including concerns about injury risk, obesity, physical inactivity, personal safety and facilities for people with disabilities. There was evidence that the information sheet was utilised by some health sector submitters (12.5%), providing tentative support for initiatives of this nature. In conclusion, the study provides novel information about the current nature of health advocacy for active transport and informs future advocacy efforts about areas for emphasis, such as health benefits of active transport, and potential alliances with other sectors such as environmental sustainability, transport and urban

  1. Home Activities for Fours.

    ERIC Educational Resources Information Center

    Ferguson-Florissant School District, Ferguson, MO.

    These home learning activity guides have been developed for parents to use with their 4-year-old children. Most of the activities require only household items that are often thrown away and can be recycled for learning activities. Some require no materials at all. The guides frequently begin with a discussion of home activities; progress through…

  2. Active commuting to school

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Declines in physical activity levels have coincided with increasing rates of obesity in children. This is problematic because physical activity has been shown to attenuate weight gain in children. Active commuting to school is one way of increasing children's physical activity. However, given the hi...

  3. Civil Law: 12 Activities.

    ERIC Educational Resources Information Center

    Dresbach, Debra

    These learning activities on civil law are intended to supplement the secondary level Scholastic materials "Living Law." Case studies, simulations, and role-play activities are included. Information provided for each activity includes a brief overview, background information, teacher instructions and a description of each activity.…

  4. Increasing Youth Physical Activity with Activity Calendars

    ERIC Educational Resources Information Center

    Eckler, Seth

    2016-01-01

    Physical educators often struggle with ways to get their students to be active beyond the school day. One strategy to accomplish this is the use of physical activity calendars (PACs). The purpose of this article is to support the use of PACs and give practical advice for creating effective PACs.

  5. Cultural Activation of Consumers.

    PubMed

    Siegel, Carole E; Reid-Rose, Lenora; Joseph, Adriana M; Hernandez, Jennifer C; Haugland, Gary

    2016-02-01

    This column discusses "cultural activation," defined as a consumer's recognition of the importance of providing cultural information to providers about cultural affiliations, challenges, views about, and attitudes toward behavioral health and general medical health care, as well as the consumer's confidence in his or her ability to provide this information. An aid to activation, "Cultural Activation Prompts," and a scale that measures a consumer's level of activation, the Cultural Activation Measurement Scale, are described. Suggestions are made about ways to introduce cultural activation as a component of usual care.

  6. Smoking, physical activity, and active life expectancy.

    PubMed

    Ferrucci, L; Izmirlian, G; Leveille, S; Phillips, C L; Corti, M C; Brock, D B; Guralnik, J M

    1999-04-01

    The effect of smoking and physical activity on active and disabled life expectancy was estimated using data from the Established Populations for Epidemiologic Studies of the Elderly (EPESE). Population-based samples of persons aged > or = 65 years from the East Boston, Massachusetts, New Haven, Connecticut, and Iowa sites of the EPESE were assessed at baseline between 1981 and 1983 and followed for mortality and disability over six annual follow-ups. A total of 8,604 persons without disability at baseline were classified as "ever" or "never" smokers and doing "low," "moderate," or "high" level physical activity. Active and disabled life expectancies were estimated using a Markov chain model. Compared with smokers, men and women nonsmokers survived 1.6-3.9 and 1.6-3.6 years longer, respectively, depending on level of physical activity. When smokers were disabled and close to death, most nonsmokers were still nondisabled. Physical activity, from low to moderate to high, was significantly associated with more years of life expectancy in both smokers (9.5, 10.5, 12.9 years in men and 11.1, 12.6, 15.3 years in women at age 65) and nonsmokers (11.0, 14.4, 16.2 years in men and 12.7, 16.2, 18.4 years in women at age 65). Higher physical activity was associated with fewer years of disability prior to death. These findings provide strong and explicit evidence that refraining from smoking and doing regular physical activity predict a long and healthy life.

  7. Population Education. Awareness Activities.

    ERIC Educational Resources Information Center

    Brouse, Deborah E.

    1990-01-01

    Described are awareness activities that deal with human population growth, resources, and the environment. Activities include simulations, mathematical exercises, and discussions of the topic. Specific examples of what individuals can do to help are listed. (KR)

  8. Major operations and activities

    SciTech Connect

    Black, D.G.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the major operations and activities on the site. These operations and activities include site management, waste management, environmental restoration and corrective actions, and research and technology development.

  9. Family Activities for Fitness

    ERIC Educational Resources Information Center

    Grosse, Susan J.

    2009-01-01

    This article discusses how families can increase family togetherness and improve physical fitness. The author provides easy ways to implement family friendly activities for improving and maintaining physical health. These activities include: walking, backyard games, and fitness challenges.

  10. Active magnetic regenerator

    DOEpatents

    Barclay, John A.; Steyert, William A.

    1982-01-01

    The disclosure is directed to an active magnetic regenerator apparatus and method. Brayton, Stirling, Ericsson, and Carnot cycles and the like may be utilized in an active magnetic regenerator to provide efficient refrigeration over relatively large temperature ranges.

  11. ACS Community Activities Contests

    NASA Astrophysics Data System (ADS)

    Burgener, Marisa

    2007-08-01

    The Committee on Community Activities and the Office of Community Activities announce the winners of the Illustrated Haiku Contest, Earth Day 2007 and the Poster Contest, National Chemistry Week 2006.

  12. Activity Theory and Ontology

    ERIC Educational Resources Information Center

    Peim, Nick

    2009-01-01

    This paper seeks to re-examine Yrio Engestrom's activity theory as a technology of knowledge designed to enable positive transformations of specific practices. The paper focuses on a key paper where Engestrom defines the nature and present state of activity theory. Beginning with a brief account of the relations between activity theory and…

  13. Measurement of Physical Activity.

    ERIC Educational Resources Information Center

    Dishman, Rod K.; Washburn, Richard A.; Schoeller, Dale A.

    2001-01-01

    Valid assessment of physical activity must be unobtrusive, practical to administer, and specific about physical activity type, frequency, duration, and intensity. Assessment methods can be categorized according to whether they provide direct or indirect (e.g., self-report) observation of physical activity, body motion, physiological response…

  14. Horticultural Practices. Activity Guides.

    ERIC Educational Resources Information Center

    Bania, Kent; Cummings, John, Ed.

    The 88 activity guides in this document are intended to supplement the initial or organized instruction of the agricultural teacher at the secondary educational level. Some of the activities require one student to complete, others may need two or more students working in a team. Some activities also require followup checking within a few days to…

  15. Highlights of 1981 activities

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The highlights of NASA's 1981 activities are presented, including the results of the two flights of the space shuttle Columbia and the Voyager 2 encounter with Saturn. Accomplishments in the areas of space transportation operations; space science; aeronautical, energy, and space research and development; as well as space tracking, international activities, and 1981 launch activities are discussed.

  16. Bonus Activity Book.

    ERIC Educational Resources Information Center

    Learning, 1992

    1992-01-01

    Provides on-task activities to fill in unexpected extra moments in elementary classes. The activities require little preparation and take 5-15 minutes to complete. There are activities for math, language arts, social science, science, critical thinking, and computer. An outer space board game is also included. (SM)

  17. Activity Sheets. Draft Copy.

    ERIC Educational Resources Information Center

    Duke Power Company, Educational Services Dept., Charlotte, NC.

    This document consists of energy vocabulary activities, three games, worksheets, laboratory activities/exercises, and an introductory classroom exercise designed to introduce energy concepts to students. Vocabulary activities focus on coal and energy consumption. The three games (with instructions) focus on various aspects of energy and energy…

  18. Technology Learning Activities I.

    ERIC Educational Resources Information Center

    International Technology Education Association, Reston, VA.

    This guide contains 30 technology learning activities. Activities may contain all or some of the following: an introduction, objectives, materials and equipment, challenges, limitations, notes and investigations, resources and references used, and evaluation ideas. Activity titles are: (1) Occupations in Construction Technology; (2) Designing a…

  19. Technology Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Brame, Ray; And Others

    This guide contains 43 modules of laboratory activities for technology education courses. Each module includes an instructor's resource sheet and the student laboratory activity. Instructor's resource sheets include some or all of the following elements: module number, course title, activity topic, estimated time, essential elements, objectives,…

  20. Computers + Student Activities Handbook.

    ERIC Educational Resources Information Center

    Masie, Elliott; Stein, Michele

    Designed to provide schools with the tools to start utilizing computers for student activity programs without additional expenditures, this handbook provides beginning computer users with suggestions and ideas for using computers in such activities as drama clubs, yearbooks, newspapers, activity calendars, accounting programs, room utilization,…

  1. Climate Change: An Activity.

    ERIC Educational Resources Information Center

    Lewis, Garry

    1995-01-01

    Presents a segment of the Geoscience Education booklet, Climate Change, that contains information and activities that enable students to gain a better appreciation of the possible effects human activity has on the Earth's climate. Describes the Terrace Temperatures activity that leads students through an investigation using foraminifera data to…

  2. Metabolism Supports Macrophage Activation

    PubMed Central

    Langston, P. Kent; Shibata, Munehiko; Horng, Tiffany

    2017-01-01

    Macrophages are found in most tissues of the body, where they have tissue- and context-dependent roles in maintaining homeostasis as well as coordinating adaptive responses to various stresses. Their capacity for specialized functions is controlled by polarizing signals, which activate macrophages by upregulating transcriptional programs that encode distinct effector functions. An important conceptual advance in the field of macrophage biology, emerging from recent studies, is that macrophage activation is critically supported by metabolic shifts. Metabolic shifts fuel multiple aspects of macrophage activation, and preventing these shifts impairs appropriate activation. These findings raise the exciting possibility that macrophage functions in various contexts could be regulated by manipulating their metabolism. Here, we review the rapidly evolving field of macrophage metabolism, discussing how polarizing signals trigger metabolic shifts and how these shifts enable appropriate activation and sustain effector activities. We also discuss recent studies indicating that the mitochondria are central hubs in inflammatory macrophage activation. PMID:28197151

  3. Current Approaches to Quantifying Tonic and Reflex Autonomic Outflows Controlling Cardiovascular Function in Humans and Experimental Animals.

    PubMed

    Salman, Ibrahim M

    2015-11-01

    The role of the autonomic nervous system in the pathophysiology of human and experimental models of cardiovascular disease is well established. In the recent years, there have been some rapid developments in the diagnostic approaches used to assess and monitor autonomic functions. Although most of these methods are devoted for research purposes in laboratory animals, many have still found their way to routine clinical practice. To name a few, direct long-term telemetry recording of sympathetic nerve activity (SNA) in rodents, single-unit SNA recording using microneurography in human subjects and spectral analysis of blood pressure and heart rate in both humans and animals have recently received an overwhelming attention. In this article, we therefore provide an overview of the methods and techniques used to assess tonic and reflex autonomic functions in humans and experimental animals, highlighting current advances available and procedure description, limitations and usefulness for diagnostic purposes.

  4. Activated carbon from biomass

    NASA Astrophysics Data System (ADS)

    Manocha, S.; Manocha, L. M.; Joshi, Parth; Patel, Bhavesh; Dangi, Gaurav; Verma, Narendra

    2013-06-01

    Activated carbon are unique and versatile adsorbents having extended surface area, micro porous structure, universal adsorption effect, high adsorption capacity and high degree of surface reactivity. Activated carbons are synthesized from variety of materials. Most commonly used on a commercial scale are cellulosic based precursors such as peat, coal, lignite wood and coconut shell. Variation occurs in precursors in terms of structure and carbon content. Coir having very low bulk density and porous structure is found to be one of the valuable raw materials for the production of highly porous activated carbon and other important factor is its high carbon content. Exploration of good low cost and non conventional adsorbent may contribute to the sustainability of the environment and offer promising benefits for the commercial purpose in future. Carbonization of biomass was carried out in a horizontal muffle furnace. Both carbonization and activation were performed in inert nitrogen atmosphere in one step to enhance the surface area and to develop interconnecting porosity. The types of biomass as well as the activation conditions determine the properties and the yield of activated carbon. Activated carbon produced from biomass is cost effective as it is easily available as a waste biomass. Activated carbon produced by combination of chemical and physical activation has higher surface area of 2442 m2/gm compared to that produced by physical activation (1365 m2/gm).

  5. Factor XII Contact Activation.

    PubMed

    Naudin, Clément; Burillo, Elena; Blankenberg, Stefan; Butler, Lynn; Renné, Thomas

    2017-03-27

    Contact activation is the surface-induced conversion of factor XII (FXII) zymogen to the serine protease FXIIa. Blood-circulating FXII binds to negatively charged surfaces and this contact to surfaces triggers a conformational change in the zymogen inducing autoactivation. Several surfaces that have the capacity for initiating FXII contact activation have been identified, including misfolded protein aggregates, collagen, nucleic acids, and platelet and microbial polyphosphate. Activated FXII initiates the proinflammatory kallikrein-kinin system and the intrinsic coagulation pathway, leading to formation of bradykinin and thrombin, respectively. FXII contact activation is well characterized in vitro and provides the mechanistic basis for the diagnostic clotting assay, activated partial thromboplastin time. However, only in the past decade has the critical role of FXII contact activation in pathological thrombosis been appreciated. While defective FXII contact activation provides thromboprotection, excess activation underlies the swelling disorder hereditary angioedema type III. This review provides an overview of the molecular basis of FXII contact activation and FXII contact activation-associated disease states.

  6. Marine Biology Activities. Ocean Related Curriculum Activities.

    ERIC Educational Resources Information Center

    Pauls, John

    The ocean affects all of our lives. Therefore, awareness of and information about the interconnections between humans and oceans are prerequisites to making sound decisions for the future. Project ORCA (Ocean Related Curriculum Activities) has developed interdisciplinary curriculum materials designed to meet the needs of students and teachers…

  7. Patterns in Active Nematics

    NASA Astrophysics Data System (ADS)

    Yeomans, Julia M.

    Active systems, from bacterial suspensions to cellular monolayers, are continuously driven out of equilibrium by local injection of energy from their constituent elements and exhibit turbulent-like, chaotic patterns. We describe how active systems can be stabilised by tuning a physical feature of the system, friction. We demonstrate how the crossover between wet active systems, whose behaviour is dominated by hydrodynamics, and dry active matter where any flow is screened, can be achieved by using friction as a control parameter and demonstrate vortex ordering at the wet-dry crossover. We show that the self organisation of vortices into lattices is accompanied by the spatial ordering of topological defects leading to active crystal-like structures. The emergence of vortex lattices which leads to the positional ordering of topological defects may be a useful step towards the design and control of active materials.

  8. Activated recombinant adenovirus proteinases

    DOEpatents

    Anderson, C.W.; Mangel, W.F.

    1999-08-10

    This application describes methods and expression constructs for producing activatable recombinant adenovirus proteinases. Purified activatable recombinant adenovirus proteinases and methods of purification are described. Activated adenovirus proteinases and methods for obtaining activated adenovirus proteinases are further included. Isolated peptide cofactors of adenovirus proteinase activity, methods of purifying and identifying peptide cofactors are also described. Antibodies immunoreactive with adenovirus proteinases, immunospecific antibodies, and methods for preparing them are also described. Other related methods and materials are also described. 29 figs.

  9. Activated recombinant adenovirus proteinases

    DOEpatents

    Anderson, Carl W.; Mangel, Walter F.

    1999-08-10

    This application describes methods and expression constructs for producing activatable recombinant adenovirus proteinases. Purified activatable recombinant adenovirus proteinases and methods of purification are described. Activated adenovirus proteinases and methods for obtaining activated adenovirus proteinases are further included. Isolated peptide cofactors of adenovirus proteinase activity, methods of purifying and identifying said peptide cofactors are also described. Antibodies immunoreactive with adenovirus proteinases, immunospecific antibodies, and methods for preparing them are also described. Other related methods and materials are also described.

  10. Activity in distant comets

    NASA Technical Reports Server (NTRS)

    Luu, Jane X.

    1992-01-01

    Activity in distant comets remains a mystery in the sense that we still have no complete theory to explain the various types of activity exhibited by different comets at large distances. This paper explores the factors that should play a role in determining activity in a distant comet, especially in the cases of comet P/Tempel 2, comet Schwassmann-Wachmann 1, and 2060 Chiron.

  11. Thermally Activated Driver

    NASA Technical Reports Server (NTRS)

    Kinard, William H.; Murray, Robert C.; Walsh, Robert F.

    1987-01-01

    Space-qualified, precise, large-force, thermally activated driver (TAD) developed for use in space on astro-physics experiment to measure abundance of rare actinide-group elements in cosmic rays. Actinide cosmic rays detected using thermally activated driver as heart of event-thermometer (ET) system. Thermal expansion and contraction of silicone oil activates driver. Potential applications in fluid-control systems where precise valve controls are needed.

  12. [Biomedical activity of biosurfactants].

    PubMed

    Krasowska, Anna

    2010-07-23

    Biosurfactants, amphiphilic compounds, synthesized by microorganisms have surface, antimicrobial and antitumor properties. Biosurfactants prevent adhesion and biofilms formation by bacteria and fungi on various surfaces. For many years microbial surfactants are used as antibiotics with board spectrum of activity against microorganisms. Biosurfactants act as antiviral compounds and their antitumor activities are mediated through induction of apoptosis. This work presents the current state of knowledge related to biomedical activity of biosurfactants.

  13. NASA metrication activities

    NASA Technical Reports Server (NTRS)

    Vlannes, P. N.

    1978-01-01

    NASA's organization and policy for metrification, history from 1964, NASA participation in Federal agency activities, interaction with nongovernmental metrication organizations, and the proposed metrication assessment study are reviewed.

  14. Active Flow Control Activities at NASA Langley

    NASA Technical Reports Server (NTRS)

    Anders, Scott G.; Sellers, William L., III; Washburn, Anthony E.

    2004-01-01

    NASA Langley continues to aggressively investigate the potential advantages of active flow control over more traditional aerodynamic techniques. This paper provides an update to a previous paper and describes both the progress in the various research areas and the significant changes in the NASA research programs. The goals of the topics presented are focused on advancing the state of knowledge and understanding of controllable fundamental mechanisms in fluids as well as to address engineering challenges. An organizational view of current research activities at NASA Langley in active flow control as supported by several projects is presented. On-center research as well as NASA Langley funded contracts and grants are discussed at a relatively high level. The products of this research are to be demonstrated either in bench-top experiments, wind-tunnel investigations, or in flight as part of the fundamental NASA R&D program and then transferred to more applied research programs within NASA, DOD, and U.S. industry.

  15. Active Students in Webinars

    ERIC Educational Resources Information Center

    Kolås, Line; Nordseth, Hugo; Yri, Jørgen Sørlie

    2015-01-01

    To ensure student activity in webinars we have defined 10 learning tasks focusing on production and communication e.g. collaborative writing, discussion and polling, and investigated how the technology supports the learning activities. The three project partners in the VisPed-project use different video-conferencing systems, and we analyzed how it…

  16. [Field Learning Activities].

    ERIC Educational Resources Information Center

    Nolde Forest Environmental Education Center, Reading, PA.

    Seventy field activities, pertinent to outdoor, environmental studies, are described in this compilation. Designed for elementary and junior high school students, the activities cover many discipline areas--science, social studies, language arts, health, history, mathematics, and art--and many are multidisciplinary in use. Topics range from soil…

  17. Warm-Up Activities.

    ERIC Educational Resources Information Center

    Mingguang, Yang

    1999-01-01

    Discusses how warm-up activities can help to make the English-as-a-foreign-language classroom a lively and interesting place. Warm-up activities are games carried out at the beginning of each class to motivate students to make good use of class time. (Author/VWL)

  18. Nutrition Activities Resource Guide.

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY. Div. of Special Education.

    The resource guide suggests activities to help special education students make appropriate choices about their nutritional habits. It is explained that the activities can be infused into other curriculum areas. The guide consists of five themes and includes performance objectives for each: foods eaten at school (planning a school lunch, keeping a…

  19. Science World Activities Book.

    ERIC Educational Resources Information Center

    Wisconsin Academy of Sciences, Arts and Letters, Madison.

    This document consists of three sections. Section I contains 19 activities developed by master teachers for the Science World '84 summer science program. These activities focus on studies involving airplane controls, trash bag kites, computers, meteorology, compass orienteering, soils, aquatic ecosystems, bogs, and others. Objectives, materials…

  20. The Journal Synthesizing Activity.

    ERIC Educational Resources Information Center

    Garber, Zev

    The journal synthesizing activity is intended to combine aspects of the formal essay with that of a diary. Activities associated with lecture topics are written up as short journal entries of approximately five typewritten pages and are turned in during the weekly class session at which the related topic is being discussed. The journal project…

  1. Activation of fly ash

    DOEpatents

    Corbin, D.R.; Velenyi, L.J.; Pepera, M.A.; Dolhyj, S.R.

    1986-08-19

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  2. Activating Event Knowledge

    ERIC Educational Resources Information Center

    Hare, Mary; Jones, Michael; Thomson, Caroline; Kelly, Sarah; McRae, Ken

    2009-01-01

    An increasing number of results in sentence and discourse processing demonstrate that comprehension relies on rich pragmatic knowledge about real-world events, and that incoming words incrementally activate such knowledge. If so, then even outside of any larger context, nouns should activate knowledge of the generalized events that they denote or…

  3. Coordinating Shared Activities

    NASA Technical Reports Server (NTRS)

    Clement, Bradley

    2004-01-01

    Shared Activity Coordination (ShAC) is a computer program for planning and scheduling the activities of an autonomous team of interacting spacecraft and exploratory robots. ShAC could also be adapted to such terrestrial uses as helping multiple factory managers work toward competing goals while sharing such common resources as floor space, raw materials, and transports. ShAC iteratively invokes the Continuous Activity Scheduling Planning Execution and Replanning (CASPER) program to replan and propagate changes to other planning programs in an effort to resolve conflicts. A domain-expert specifies which activities and parameters thereof are shared and reports the expected conditions and effects of these activities on the environment. By specifying these conditions and effects differently for each planning program, the domain-expert subprogram defines roles that each spacecraft plays in a coordinated activity. The domain-expert subprogram also specifies which planning program has scheduling control over each shared activity. ShAC enables sharing of information, consensus over the scheduling of collaborative activities, and distributed conflict resolution. As the other planning programs incorporate new goals and alter their schedules in the changing environment, ShAC continually coordinates to respond to unexpected events.

  4. Activities: More Calculator Capers.

    ERIC Educational Resources Information Center

    Schmalz, Rosemary

    1983-01-01

    Provided is an activity designed to give grades 7-12 students opportunities to discover numerical patterns and to derive general conclusions from observing data. The activity focuses attention on patterns in products such as 33x34, 333x334, and 3333x3334. Three worksheets and answers are included. (JN)

  5. Choreography of AMPK activation.

    PubMed

    Langendorf, Christopher G; Kemp, Bruce E

    2015-01-01

    A recent study published in Cell Research by Li and colleagues reports a detailed biophysical and structural study of AMPK's intra-molecular interactions during activation. By employing subunit tagging and proximity analysis with the aid of AlphaScreen instrumentation, Li et al. add to our understanding of the choreography of activation of AMPK by both nucleotides and phosphorylation.

  6. Rainy Day Activities.

    ERIC Educational Resources Information Center

    Texas Child Care, 1997

    1997-01-01

    Experienced caregivers plan ahead for rainy days. This article describes specific rainy day activities for young children, such as books and crafts to learn about rain (rain in a jar, making a rainbow), simple cooking activities (taffy pull, cinnamon candy tea), and games (mummy wrap, hunt the thimble, rain lotto). (EV)

  7. Laboratory Activities in Israel

    ERIC Educational Resources Information Center

    Mamlok-Naaman, Rachel; Barnea, Nitza

    2012-01-01

    Laboratory activities have long had a distinctive and central role in the science curriculum, and science educators have suggested that many benefits accrue from engaging students in science laboratory activities. Many research studies have been conducted to investigate the educational effectiveness of laboratory work in science education in…

  8. Peak Longevity Physical Activity

    Cancer.gov

    People who engage in three to five times the recommended minimum level of leisure-time physical activity derive the greatest benefit in terms of mortality reduction when compared with people who do not engage in leisure-time physical activity.

  9. Curriculum Activities on Aging.

    ERIC Educational Resources Information Center

    Schmall, Vicki L.; Benge, Nancy

    This paper contains learning activities on aging for use with elementary, high school, and university students in health, family relationships, social studies, and art courses. The activities are intended to help youth develop a more realistic understanding of the aging process and to become aware of both the problems and benefits associated with…

  10. Students Active in Leadership.

    ERIC Educational Resources Information Center

    Brutcher, Robert

    2001-01-01

    Describes SAIL (Students Active in Leadership) as a school-based, youth-directed group. States that the program helps teenagers learn leadership skills by developing and implementing community service activities. SAIL finds partners with whom to collaborate among local businesses, government, and health associations, and these partners provide the…

  11. Ten Minute Writing Activities.

    ERIC Educational Resources Information Center

    Markus, Sharyn

    Designed with junior high school students in mind, the activities in this booklet are offered as ways to stimulate interest in writing using as little as ten minutes of class time. The activities are arranged in six sections: (1) developing observation skills and paying attention to details; (2) word play, descriptive words, and word collections…

  12. Nature's engines: active matter

    NASA Astrophysics Data System (ADS)

    Yeomans, Julia M.

    2017-03-01

    Active materials, bacteria, molecular motors, and self-propelled colloids, continuously transform chemical energy from the environment to mechanical work. Dense active matter, from layers of cells to flocks of birds, self-assembles into intricate patterns. Nature's engines are complex and efficient, and we would like to exploit her ideas to fabricate nano-machines.

  13. Activation of fly ash

    DOEpatents

    Corbin, David R.; Velenyi, Louis J.; Pepera, Marc A.; Dolhyj, Serge R.

    1986-01-01

    Fly ash is activated by heating a screened magnetic fraction of the ash in a steam atmosphere and then reducing, oxidizing and again reducing the hydrothermally treated fraction. The activated fly ash can be used as a carbon monoxide disproportionating catalyst useful in the production of hydrogen and methane.

  14. Activity Book: Ocean Ecology.

    ERIC Educational Resources Information Center

    Learning, 1992

    1992-01-01

    Presents a collection of activities to help elementary students study ocean ecology. The activities have students investigate ocean inhabitants, analyze animal adaptations, examine how temperature and saltiness affect ocean creatures, and learn about safeguarding the sea. Student pages offer reproducible learning sheets. (SM)

  15. [Biosignals of dermal activity].

    PubMed

    Rathkolb, O; Gallei, L

    1993-01-01

    Electrodermal activity (EDA) summarizes different electrophysiological dimensions of human skin. EDA is based on the activity of sweat glands and their innervation by the autonomic nervous system. EDA is used as indicator in the additional diagnostic assessment of patients in the fields of neurology and psychosomatic medicine.

  16. Active galactic nuclei

    PubMed Central

    Fabian, Andrew C.

    1999-01-01

    Active galactic nuclei are the most powerful, long-lived objects in the Universe. Recent data confirm the theoretical idea that the power source is accretion into a massive black hole. The common occurrence of obscuration and outflows probably means that the contribution of active galactic nuclei to the power density of the Universe has been generally underestimated. PMID:10220363

  17. Reflections on Activity Theory

    ERIC Educational Resources Information Center

    Bakhurst, David

    2009-01-01

    It is sometimes suggested that activity theory represents the most important legacy of Soviet philosophy and psychology. But what exactly "is" activity theory? The canonical account in the West is given by Engestrom, who identifies three stages in the theory's development: from Vygotsky's insights, through Leontiev's articulation of the…

  18. Student Activities. Managing Liability.

    ERIC Educational Resources Information Center

    Bennett, Barbara; And Others

    This monograph suggests ways that college or university administrations can undertake a systematic and careful review of the risks posed by students' activities. Its purpose is to provide guidance in integrating the risk management process into a school's existing approaches to managing student organizations and activities. It is noted that no…

  19. The Activity of Trypsin

    ERIC Educational Resources Information Center

    Russo, Salvatore F.; Holzman, Tom

    1977-01-01

    Describes an experiment that illustrates the following points concerning the experimental determination of trypsin activity: (1) there is a difference in basing enzyme concentration on weight, absorbance, or active sites; and (2) the method of expressing enzyme concentration determines the value of specific, molecular, and catalytic center…

  20. Metastasis and AKT activation.

    PubMed

    Qiao, Meng; Sheng, Shijie; Pardee, Arthur B

    2008-10-01

    Metastasis is responsible for 90% of cancer patient deaths. More information is needed about the molecular basis for its potential detection and treatment. The activated AKT kinase is necessary for many events of the metastatic pathway including escape of cells from the tumor's environment, into and then out of the circulation, activation of proliferation, blockage of apoptosis, and activation of angiogenesis. A series of steps leading to metastatic properties can be initiated upon activation of AKT by phosphorylation on Ser-473. These findings lead to the question of how this activation is connected to metastasis. Activated AKT phosphorylates GSK-3beta causing its proteolytic removal. This increases stability of the negative transcription factor SNAIL, thereby decreasing transcription of the transmembrane protein E-cadherin that forms adhesions between adjacent cells, thereby permitting their detachment. How is AKT hyperactivated in metastatic cells? Increased PI3K or TORC2 kinase activity- or decreased PHLPP phosphatase could be responsible. Furthermore, a positive feedback mechanism is that the decrease of E-cadherin lowers PTEN and thereby increases PIP3, further activating AKT and metastasis.

  1. Aging and Semantic Activation.

    ERIC Educational Resources Information Center

    Howard, Darlene V.

    Three studies tested the theory that long term memory consists of a semantically organized network of concept nodes interconnected by leveled associations or relations, and that when a stimulus is processed, the corresponding concept node is assumed to be temporarily activated and this activation spreads to nearby semantically related nodes. In…

  2. Activities of the ILO.

    ERIC Educational Resources Information Center

    Labour Education, 1984

    1984-01-01

    Seven articles on International Labour Organization (ILO) activities cover study groups at ILO headquarters, a Philippine rural workers seminar, women's participation in Central American union activities, worksite courses in India, and seminars and symposia in Cape Verde, Mauritius, and Sierra Leone. (SK)

  3. Learning Activities for Toddlers.

    ERIC Educational Resources Information Center

    Texas Child Care, 1996

    1996-01-01

    Suggests activities to help toddlers develop skills in the four important areas of self-help, creativity, world mastery, and coordination. Activities include hand washing, button practice, painting, movement and music, bubble making, creation of a nature mural, and a shoe print trail. (TJQ)

  4. Active and Healthy Schools

    ERIC Educational Resources Information Center

    Ball, Stephen; Kovarik, Jessica; Leidy, Heather

    2015-01-01

    The Active and Healthy School Program (AHS) can be used to alter the culture and environment of a school to help children make healthier choices. The purpose of this study was to determine the effectiveness of AHS to increase physical activity while decreasing total screen time, increase healthy food choices, and improve knowledge about physical…

  5. ZOOMsci Activity Guide.

    ERIC Educational Resources Information Center

    Wade, Meredith

    This activity guide is based on the Public Broadcasting System's (PBS) program "ZOOM." It is designed for educators with activities that are categorized into three themes: (1) Things That Go, which includes "Air" which explores air pressure, "Rubber Bands" which discovers the potential energy of rubber bands,…

  6. Emotionally Intense Science Activities

    ERIC Educational Resources Information Center

    King, Donna; Ritchie, Stephen; Sandhu, Maryam; Henderson, Senka

    2015-01-01

    Science activities that evoke positive emotional responses make a difference to students' emotional experience of science. In this study, we explored 8th Grade students' discrete emotions expressed during science activities in a unit on Energy. Multiple data sources including classroom videos, interviews and emotion diaries completed at the end of…

  7. Active optical zoom system

    DOEpatents

    Wick, David V.

    2005-12-20

    An active optical zoom system changes the magnification (or effective focal length) of an optical imaging system by utilizing two or more active optics in a conventional optical system. The system can create relatively large changes in system magnification with very small changes in the focal lengths of individual active elements by leveraging the optical power of the conventional optical elements (e.g., passive lenses and mirrors) surrounding the active optics. The active optics serve primarily as variable focal-length lenses or mirrors, although adding other aberrations enables increased utility. The active optics can either be LC SLMs, used in a transmissive optical zoom system, or DMs, used in a reflective optical zoom system. By appropriately designing the optical system, the variable focal-length lenses or mirrors can provide the flexibility necessary to change the overall system focal length (i.e., effective focal length), and therefore magnification, that is normally accomplished with mechanical motion in conventional zoom lenses. The active optics can provide additional flexibility by allowing magnification to occur anywhere within the FOV of the system, not just on-axis as in a conventional system.

  8. Emotionally Intense Science Activities

    NASA Astrophysics Data System (ADS)

    King, Donna; Ritchie, Stephen; Sandhu, Maryam; Henderson, Senka

    2015-08-01

    Science activities that evoke positive emotional responses make a difference to students' emotional experience of science. In this study, we explored 8th Grade students' discrete emotions expressed during science activities in a unit on Energy. Multiple data sources including classroom videos, interviews and emotion diaries completed at the end of each lesson were analysed to identify individual student's emotions. Results from two representative students are presented as case studies. Using a theoretical perspective drawn from theories of emotions founded in sociology, two assertions emerged. First, during the demonstration activity, students experienced the emotions of wonder and surprise; second, during a laboratory activity, students experienced the intense positive emotions of happiness/joy. Characteristics of these activities that contributed to students' positive experiences are highlighted. The study found that choosing activities that evoked strong positive emotional experiences, focused students' attention on the phenomenon they were learning, and the activities were recalled positively. Furthermore, such positive experiences may contribute to students' interest and engagement in science and longer term memorability. Finally, implications for science teachers and pre-service teacher education are suggested.

  9. List 9 - Active CERCLIS Sites:

    EPA Pesticide Factsheets

    The List 9 displays the sequence of activities undertaken at active CERCLIS sites. An active site is one at which site assessment, removal, remedial, enforcement, cost recovery, or oversight activities are being planned or conducted.

  10. THE ACTIVE CENTAURS

    SciTech Connect

    Jewitt, David

    2009-05-15

    The Centaurs are recent escapees from the Kuiper Belt that are destined either to meet fiery oblivion in the hot inner regions of the solar system or to be ejected to the interstellar medium by gravitational scattering from the giant planets. Dynamically evolved Centaurs, when captured by Jupiter and close enough to the Sun for near-surface water ice to sublimate, are conventionally labeled as 'short-period' (specifically, Jupiter-family) comets. Remarkably, some Centaurs show comet-like activity even when far beyond the orbit of Jupiter, suggesting mass loss driven by a process other than the sublimation of water ice. We observed a sample of 23 Centaurs and found nine to be active, with mass-loss rates measured from several kg s{sup -1} to several tonnes s{sup -1}. Considered as a group, we find that the 'active Centaurs' in our sample have perihelia smaller than the inactive Centaurs (median 5.9 AU versus 8.7 AU), and smaller than the median perihelion distance computed for all known Centaurs (12.4 AU). This suggests that their activity is thermally driven. We consider several possibilities for the origin of the mass loss from the active Centaurs. Most are too cold for activity at the observed levels to originate via the sublimation of crystalline water ice. Solid carbon monoxide and carbon dioxide have the opposite problem: they are so volatile that they should drive activity in Centaurs at much larger distances than observed. We consider the possibility that activity in the Centaurs is triggered by the conversion of amorphous ice into the crystalline form accompanied by the release of trapped gases, including carbon monoxide. By imposing the condition that crystallization should occur when the crystallization time is shorter than the orbital period we find a qualitative match to the perihelion distribution of the active Centaurs and conclude that the data are consistent with the hypothesis that the Centaurs contain amorphous ice.

  11. Physics of solar activity

    NASA Technical Reports Server (NTRS)

    Sturrock, Peter A.

    1993-01-01

    The aim of the research activity was to increase our understanding of solar activity through data analysis, theoretical analysis, and computer modeling. Because the research subjects were diverse and many researchers were supported by this grant, a select few key areas of research are described in detail. Areas of research include: (1) energy storage and force-free magnetic field; (2) energy release and particle acceleration; (3) radiation by nonthermal electrons; (4) coronal loops; (5) flare classification; (6) longitude distributions of flares; (7) periodicities detected in the solar activity; (8) coronal heating and related problems; and (9) plasma processes.

  12. Algorithm-development activities

    NASA Technical Reports Server (NTRS)

    Carder, Kendall L.

    1994-01-01

    The task of algorithm-development activities at USF continues. The algorithm for determining chlorophyll alpha concentration, (Chl alpha) and gelbstoff absorption coefficient for SeaWiFS and MODIS-N radiance data is our current priority.

  13. MARIHUANA ACTIVITY OF CANNABINOL.

    PubMed

    Loewe, S

    1945-12-14

    Cannabinol, generally believed to be an inert component of hemp oil, is shown to have marihuana activity. The significance of this observation with regard to the relationship between structure and mamactivity in the class of cannabinols is discussed.

  14. Balance Food and Activity

    MedlinePlus

    ... eNewsletters Calendar Balance Food and Activity What is Energy Balance? Energy is another word for "calories." Your ... adults, fewer calories are needed at older ages. Energy Balance in Real Life Think of it as ...

  15. Activities in Teaching Weather

    ERIC Educational Resources Information Center

    Tonn, Martin

    1977-01-01

    Presented is a unit composed of activities for teaching weather. Topics include cloud types and formation, simple weather instruments, and the weather station. Illustrations include a weather chart and instruments. A bibliography is given. (MA)

  16. Extravehicular activity technology discipline

    NASA Technical Reports Server (NTRS)

    Webbon, Bruce W.

    1990-01-01

    Viewgraphs on extravehicular activity technology discipline for Space Station Freedom are presented. Topics covered include: extravehicular mobility unit; airlock and EMU support equipment; tools, mobility aids, and workstations; and telerobotic work aids interfaces.

  17. French space activities

    NASA Technical Reports Server (NTRS)

    Blanc, R.

    1982-01-01

    The four main points of research and development of space programs by France are explained. The National Center of Space Studies is discussed, listing the missions of the Center and describing the activities of the staff.

  18. Active Fire Mapping Program

    MedlinePlus

    Active Fire Mapping Program Current Large Incidents (Home) New Large Incidents Fire Detection Maps MODIS Satellite Imagery VIIRS Satellite Imagery Fire Detection GIS Data Fire Data in Google Earth ...

  19. ERLN Activities Details

    EPA Pesticide Factsheets

    Environmental Response Laboratory Network activities include the All Hazard Receipt Facility and Screening Protocol, standardizing chemical methods, Chemical Warfare Agent Fixed Laboratory Pilot Project, microbial efforts, and WLA response plan.

  20. The Activity Centre.

    ERIC Educational Resources Information Center

    Australian Mathematics Teacher, 1989

    1989-01-01

    Presents four examples on arithmetic mean and harmonic mean. Provides solution of each of the examples and instructional activities related to the examples. Lists eight references on mathematical problem solving. (YP)

  1. Active at Any Size

    MedlinePlus

    ... a row. Your muscles need time to recover. Mind and body exercise Your local hospital or fitness, ... can be viewed at www.ClinicalTrials.gov . Additional Reading Tips to Help You Get Active Identifies and ...

  2. Exercise and activity - children

    MedlinePlus

    ... and most other organized sports (such as soccer, swimming, and dancing) Younger children cannot stick with the ... your child's preferences and abilities. Individual activities include swimming, running, skiing, or biking. Group sports are another ...

  3. Active terahertz metamaterials

    SciTech Connect

    Chen, Hou-tong

    2009-01-01

    We demonstrate planar terahertz metamaterial devices enabling actively controllable transmission amplitude, phase, or frequency at room temperature via carrier depletion or photoexcitation in the semiconductor substrate or in semiconductor materials incorporated into the metamaterial structure.

  4. Enrichment Activities for Geometry.

    ERIC Educational Resources Information Center

    Usiskin, Zalman

    1983-01-01

    Enrichment activities that teach about geometry as they instruct in geometry are given for some significant topics. The facets of geometry included are tessellations, round robin tournaments, geometric theorems on triangles, and connections between geometry and complex numbers. (MNS)

  5. Interactive Design Activism

    NASA Astrophysics Data System (ADS)

    Goulev, Petar; Farrer, Joan

    The following sections are included: * Introduction * Computers and Human Well-being * To Fuzzy or Yes (No)! * Interactive Design Activism * Sensing the Sun * Personalised Public Health Advice * Modifying Human Behaviour * Transdisciplinarity, Knowledge Transfer and Multi-domain

  6. Island Watershed Activity.

    ERIC Educational Resources Information Center

    Benson, Rod

    2003-01-01

    Describes a 90-minute "Island Watershed" activity to help earth science students understand the concept of the water cycle. Introduces a surface waters unit appropriate for students in grades 7-10. Includes watershed project guidelines. (Author/KHR)

  7. Active Limiters For Photodetectors

    NASA Technical Reports Server (NTRS)

    Katz, Joseph; Cheng, Li-Jen

    1990-01-01

    Active or "smart" electro-optical shutters proposed for protection of photodetectors, imaging devices, and other sensitive optical or optoelectronic elements. Responds rapidly and automatically to increase in illumination above prescribed level.

  8. Math Lab Activities

    ERIC Educational Resources Information Center

    Brumbaugh, Douglas K.; Hynes, Michael C.

    1974-01-01

    The goals, objects, materials and grade levels are specified in this description of a laboratory activity involving analytic geometry concepts. Students mark out bicycle gymkhana courses in which directions to participants are given by Cartesian coordinates. (JP)

  9. Low activation ferritic alloys

    DOEpatents

    Gelles, David S.; Ghoniem, Nasr M.; Powell, Roger W.

    1986-01-01

    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  10. Low activation ferritic alloys

    DOEpatents

    Gelles, D.S.; Ghoniem, N.M.; Powell, R.W.

    1985-02-07

    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  11. RAVEN Quality Assurance Activities

    SciTech Connect

    Cogliati, Joshua Joseph

    2015-09-01

    This report discusses the quality assurance activities needed to raise the Quality Level of Risk Analysis in a Virtual Environment (RAVEN) from Quality Level 3 to Quality Level 2. This report also describes the general RAVEN quality assurance activities. For improving the quality, reviews of code changes have been instituted, more parts of testing have been automated, and improved packaging has been created. For upgrading the quality level, requirements have been created and the workflow has been improved.

  12. Activated partial thromboplastin time.

    PubMed

    Ignjatovic, Vera

    2013-01-01

    Activated partial thromboplastin time (APTT) is a commonly used coagulation assay that is easy to perform, is affordable, and is therefore performed in most coagulation laboratories, both clinical and research, worldwide. The APTT is based on the principle that in citrated plasma, the addition of a platelet substitute, factor XII activator, and CaCl2 allows for formation of a stable clot. The time required for the formation of a stable clot is recorded in seconds and represents the actual APTT result.

  13. Active aperture phased arrays

    NASA Astrophysics Data System (ADS)

    Shenoy, R. P.

    1989-04-01

    Developments towards the realization of active aperture phased arrays are reviewed. The technology and cost aspects of the power amplifier and phase shifter subsystems are discussed. Consideration is given to research concerning T/R modules, MESFETs, side lobe control, beam steering, optical control techniques, and printed circuit antennas. Methods for configuring the array are examined, focusing on the tile and brick configurations. It is found that there is no technological impediment for introducing active aperture phased arrays.

  14. Intercreativity: Mapping Online Activism

    NASA Astrophysics Data System (ADS)

    Meikle, Graham

    How do activists use the Internet? This article maps a wide range of activist practice and research by applying and developing Tim Berners-Lee's concept of ‘intercreativity' (1999). It identifies four dimensions of Net activism: intercreative texts, tactics, strategies and networks. It develops these through examples of manifestations of Net activism around one cluster of issues: support campaigns for refugees and asylum seekers.

  15. ABB: active bandwidth broker

    NASA Astrophysics Data System (ADS)

    Wong, Kason; Law, Eddie

    2001-07-01

    In this paper, we shall discuss a novel design on the policy-based management for the Internet. This design deploys the concept of active networking. As opposed to the traditional network design, active network empowers network node with the ability to manipulate data and program code in packets, and configure the network properties according to the needs of different applications. The policy-based management can control network routers in order to realize end-to-end Quality of Service (QoS), such as differentiated and integrated services, across the Internet. For the moment, the Internet Engineering Task Force (IETF) has defined the framework of the policy-based management. It employs a simple client/server model that uses Common Open Policy Service (COPS) protocol to facilitate policy management and control. Our design of Active Bandwidth Broker (ABB) belongs to an active application. Our goals are to distribute centralized workload of the policy-based management over multiple active nodes in the active networks, introduce mobility of the bandwidth brokers, and allows load sharing to the policy-based management. This results a network-wide intelligent, highly available, and consistent QoS control that allows performance protection for voice, video and Internet business application while reducing costs for growing networks.

  16. Rheology of Active Gels

    NASA Astrophysics Data System (ADS)

    Chen, Daniel

    2015-03-01

    Active networks drive a diverse range of critical processes ranging from motility to division in living cells, yet a full picture of their rheological capabilities in non-cellular contexts is still emerging, e.g., How does the rheological response of a network capable of remodeling under internally-generated stresses differ from that of a passive biopolymer network? In order to address this and other basic questions, we have engineered an active gel composed of microtubules, bidirectional kinesin motors, and molecular depletant that self-organizes into a highly dynamic network of active bundles. The network continually remodels itself under ATP-tunable cycles of extension, buckling, fracturing, and self-healing. Using confocal rheometry we have simultaneously characterized the network's linear and non-linear rheological responses to shear deformation along with its dynamic morphology. We find several surprising and unique material properties for these active gels; most notably, rheological cloaking, the ability of the active gel to drive large-scale fluid mixing over several orders of flow magnitude while maintaining an invariant, solid-like rheological profile and spontaneous flow under confinement, the ability to exert micro-Newton forces to drive persistent directed motion of the rheometer tool. Taken together, these results and others to be discussed highlight the rich stress-structure-dynamics relationships in this class of biologically-derived active gels.

  17. Antimicrobial activity of flavonoids.

    PubMed

    Cushnie, T P Tim; Lamb, Andrew J

    2005-11-01

    Flavonoids are ubiquitous in photosynthesising cells and are commonly found in fruit, vegetables, nuts, seeds, stems, flowers, tea, wine, propolis and honey. For centuries, preparations containing these compounds as the principal physiologically active constituents have been used to treat human diseases. Increasingly, this class of natural products is becoming the subject of anti-infective research, and many groups have isolated and identified the structures of flavonoids possessing antifungal, antiviral and antibacterial activity. Moreover, several groups have demonstrated synergy between active flavonoids as well as between flavonoids and existing chemotherapeutics. Reports of activity in the field of antibacterial flavonoid research are widely conflicting, probably owing to inter- and intra-assay variation in susceptibility testing. However, several high-quality investigations have examined the relationship between flavonoid structure and antibacterial activity and these are in close agreement. In addition, numerous research groups have sought to elucidate the antibacterial mechanisms of action of selected flavonoids. The activity of quercetin, for example, has been at least partially attributed to inhibition of DNA gyrase. It has also been proposed that sophoraflavone G and (-)-epigallocatechin gallate inhibit cytoplasmic membrane function, and that licochalcones A and C inhibit energy metabolism. Other flavonoids whose mechanisms of action have been investigated include robinetin, myricetin, apigenin, rutin, galangin, 2,4,2'-trihydroxy-5'-methylchalcone and lonchocarpol A. These compounds represent novel leads, and future studies may allow the development of a pharmacologically acceptable antimicrobial agent or class of agents.

  18. Phytase activity in lichens.

    PubMed

    Higgins, Niall F; Crittenden, Peter D

    2015-10-01

    Phytase activity was investigated in 13 lichen species using a novel assay method. The work tested the hypothesis that phytase is a component of the suite of surface-bound lichen enzymes that hydrolyse simple organic forms of phosphorus (P) and nitrogen (N) deposited onto the thallus surface. Hydrolysis of inositol hexaphosphate (InsP6 , the substrate for phytase) and appearance of lower-order inositol phosphates (InsP5 -InsP1 ), the hydrolysis products, were measured by ion chromatography. Phytase activity in Evernia prunastri was compared among locations with contrasting rates of N deposition. Phytase activity was readily measurable in epiphytic lichens (e.g. 11.3 μmol InsP6 hydrolysed g(-1)  h(-1) in Bryoria fuscescens) but low in two terricolous species tested (Cladonia portentosa and Peltigera membranacea). Phytase and phosphomonoesterase activities were positively correlated amongst species. In E. prunastri both enzyme activities were promoted by N enrichment and phytase activity was readily released into thallus washings. InsP6 was not detected in tree canopy throughfall but was present in pollen leachate. Capacity to hydrolyse InsP6 appears widespread amongst lichens potentially promoting P capture from atmospheric deposits and plant leachates, and P cycling in forest canopies. The enzyme assay used here might find wider application in studies on plant root-fungal-soil systems.

  19. Menstrual cycle effects on sympathetic neural responses to upright tilt.

    PubMed

    Fu, Qi; Okazaki, Kazunobu; Shibata, Shigeki; Shook, Robin P; VanGunday, Tiffany B; Galbreath, M Melyn; Reelick, Miriam F; Levine, Benjamin D

    2009-05-01

    Young women are more susceptible to orthostatic intolerance than men, though the sex-specific pathophysiology remains unknown. As blood pressure (BP) is regulated through the baroreflex mechanism, we tested the hypothesis that baroreflex control of muscle sympathetic nerve activity (MSNA) during orthostasis is impaired in women and can be affected by the menstrual cycle. MSNA and haemodynamics were measured supine and during a graded upright tilt (30 deg for 6 min, 60 deg for 45 min or till presyncope) in 11 young men and 11 women during the early follicular (EFP) and mid-luteal phase (MLP) of the menstrual cycle. Sympathetic baroreflex sensitivity was quantified using the slope of the linear correlation between total activity and diastolic BP during spontaneous breathing. Baroreflex function was further assessed during a Valsalva manoeuvre (VM). Although MSNA burst frequency responses during tilting were similar between sexes and menstrual phases, increases in total activity were lower in women during EFP than MLP (P = 0.030), while total peripheral resistance and plasma noradrenaline were not similarly lower; upright total activity tended to be lower in women during EFP than men (P = 0.102). Sympathetic baroreflex sensitivity did not differ between sexes (P = 0.676) supine (-281 +/- 46 (S.E.M.) units beat(-1) mmHg(-1) in men vs -252 +/- 52 in EFP and -272 +/- 40 in MLP in women), at 30 deg tilt (-648 +/- 129 vs -611 +/- 79 and -487 +/- 94), and at 60 deg tilt (-792 +/- 135 vs -831 +/- 92 and -814 +/- 142); this sensitivity was not affected by the menstrual cycle (P = 0.747). Similar sympathetic baroreflex sensitivity between sexes and phases was also observed during the VM. Cardiovagal baroreflex sensitivity assessed during decreasing BP (i.e. early phase II of the VM) was comparable between sexes, but it was greater in men than women during increasing BP (i.e. phase IV); the menstrual cycle had no influences on cardiovagal baroreflex sensitivity. We conclude

  20. T cell activation.

    PubMed

    Smith-Garvin, Jennifer E; Koretzky, Gary A; Jordan, Martha S

    2009-01-01

    This year marks the 25th anniversary of the first Annual Review of Immunology article to describe features of the T cell antigen receptor (TCR). In celebration of this anniversary, we begin with a brief introduction outlining the chronology of the earliest studies that established the basic paradigm for how the engaged TCR transduces its signals. This review continues with a description of the current state of our understanding of TCR signaling, as well as a summary of recent findings examining other key aspects of T cell activation, including cross talk between the TCR and integrins, the role of costimulatory molecules, and how signals may negatively regulate T cell function.Acronyms and DefinitionsAdapter protein: cellular protein that functions to bridge molecular interactions via characteristic domains able to mediate protein/protein or protein/lipid interactions Costimulation: signals delivered to T cells by cell surface receptors other than the TCR itself that potentiate T cell activation cSMAC: central supramolecular activation cluster Immunoreceptor tyrosine-based activation motif (ITAM): a short peptide sequence in the cytoplasmic tails of key surface receptors on hematopoietic cells that is characterized by tyrosine residues that are phosphorylated by Src family PTKs, enabling the ITAM to recruit activated Syk family kinases Inside-out signaling: signals initiated by engagement of immunoreceptors that lead to conformational changes and clustering of integrins, thereby increasing the affinity and avidity of the integrins for their ligands NFAT: nuclear factor of activated T cells PI3K: phosphoinositide 3-kinase PKC: protein kinase C PLC: phospholipase C pMHC: peptide major histocompatibility complex (MHC) complex pSMAC: peripheral supramolecular activation cluster PTK: protein tyrosine kinase Signal transduction: biochemical events linking surface receptor engagement to cellular responses TCR: T cell antigen receptor

  1. Sirtuin activators and inhibitors

    PubMed Central

    Villalba, José M.; Alcaín, Francisco J.

    2012-01-01

    Sirtuins 1-7 (SIRT1-7) belong to the third class of deacetylase enzymes, which are dependent on NAD+ for activity. Sirtuins activity is linked to gene repression, metabolic control, apoptosis and cell survival, DNA repair, development, inflammation, neuroprotection and healthy aging. Because sirtuins modulation could have beneficial effects on human diseases there is a growing interest in the discovery of small molecules modifying their activity. We review here those compounds known to activate or inhibit sirtuins, discussing the data that support the use of sirtuin-based therapies. Almost all sirtuin activators have been described only for SIRT1. Resveratrol is a natural compound which activates SIRT1, and may help in the treatment or prevention of obesity, and in preventing tumorigenesis and the aging-related decline in heart function and neuronal loss. Due to its poor bioavailability, reformulated versions of resveratrol with improved bioavailability have been developed (resVida, Longevinex®, SRT501). Molecules that are structurally unrelated to resveratrol (SRT1720, SRT2104, SRT2379, among others) have been also developed to stimulate sirtuin activities more potently than resveratrol. Sirtuin inhibitors with a wide range of core structures have been identified for SIRT1, SIRT2, SIRT3 and SIRT5 (splitomicin, sirtinol, AGK2, cambinol, suramin, tenovin, salermide, among others). SIRT1 inhibition has been proposed in the treatment of cancer, immunodeficiency virus infections, Fragile X mental retardation syndrome and for preventing or treating parasitic diseases, whereas SIRT2 inhibitors might be useful for the treatment of cancer and neurodegenerative diseases. PMID:22730114

  2. Antimutagenic activity of spearmint.

    PubMed

    Yu, Tian-Wei; Xu, Meirong; Dashwood, Roderick H

    2004-01-01

    The antimutagenic activity of spearmint (Mentha spicata), a popular food flavoring agent, was studied in the Salmonella assay. Spearmint leaves were brewed in hot water for 5 min at concentrations up to 5% (w/v), and the water extracts were tested against the direct-acting mutagens 4-nitro-1,2-phenylenediamine (NPD) and 2-hydroxyamino-3-methyl-3H-imidazo[4,5-f]quinoline (N-OH-IQ) using Salmonella typhimurium strain TA98. Nontoxic concentrations of spearmint extract inhibited the mutagenic activity of N-OH-IQ in a concentration-dependent fashion, but had no effect against NPD. These experiments by design focused on the water extract consumed commonly as an herbal tea, but chloroform and methanol extracts of spearmint also possessed antimutagenic activity against N-OH-IQ. Water extract of spearmint inhibited the mutagenic activity of the parent compound, 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ), in the presence of rat liver S9; however, the concentration for 50% inhibition (IC50) against IQ was approximately 10-fold higher than in assays with N-OH-IQ minus S9. At concentrations similar to those used in the Salmonella assays, spearmint extract inhibited two of the major enzymes that play a role in the metabolic activation of IQ, namely, cytochromes P4501A1 and 1A2, based on ethoxyresorufin O-deethylase and methoxyresorufin O-demethylase assays in vitro. In vivo, rats were given spearmint water extract (2%; w/v) as the sole source of drinking fluid before, during, and after 2-week treatment with IQ; colonic aberrant crypt foci were inhibited significantly at 8 weeks (P < 0.05, compared with rats given IQ alone). Collectively, these findings suggest that spearmint tea protects against IQ and possibly other heterocyclic amines through inhibition of carcinogen activation and via direct effects on the activated metabolite(s).

  3. [Inflammasome: activation mechanisms].

    PubMed

    Suárez, Raibel; Buelvas, Neudo

    2015-03-01

    Inflammation is a rapid biologic response of the immune system in vascular tissues, directed to eliminate stimuli capable of causing damage and begin the process of repair. The macromolecular complexes known as "inflammasomes" are formed by a receptor, either NOD (NLR) or ALR, the receptor absent in melanoma 2 (AIM2). In addition, the inflammasome is formed by the speck-like protein associated to apoptosis (ASC) and procaspase-1, that may be activated by variations in the ionic and intracellular and extracellular ATP concentrations; and the loss of stabilization of the fagolisosomme by internalization of insoluble crystals and redox mechanisms. As a result, there is activation of the molecular platform and the processing of inflammatory prointerleukins to their active forms. There are two modalities of activation of the inflammasome: canonical and non-canonical, both capable of generating effector responses. Recent data associate NLRP 3, IL-1β and IL-18 in the pathogenesis of a variety of diseases, including atherosclerosis, type II diabetes, hyperhomocysteinemia, gout, malaria and hypertension. The inflammasome cascade is emerging as a new chemotherapeutic target in these diseases. In this review we shall discuss the mechanisms of activation and regulation of the inflammasome that stimulate, modulate and resolve inflammation.

  4. Chromatin as active matter

    NASA Astrophysics Data System (ADS)

    Agrawal, Ankit; Ganai, Nirmalendu; Sengupta, Surajit; Menon, Gautam I.

    2017-01-01

    Active matter models describe a number of biophysical phenomena at the cell and tissue scale. Such models explore the macroscopic consequences of driving specific soft condensed matter systems of biological relevance out of equilibrium through ‘active’ processes. Here, we describe how active matter models can be used to study the large-scale properties of chromosomes contained within the nuclei of human cells in interphase. We show that polymer models for chromosomes that incorporate inhomogeneous activity reproduce many general, yet little understood, features of large-scale nuclear architecture. These include: (i) the spatial separation of gene-rich, low-density euchromatin, predominantly found towards the centre of the nucleus, vis a vis. gene-poor, denser heterochromatin, typically enriched in proximity to the nuclear periphery, (ii) the differential positioning of individual gene-rich and gene-poor chromosomes, (iii) the formation of chromosome territories, as well as (iv), the weak size-dependence of the positions of individual chromosome centres-of-mass relative to the nuclear centre that is seen in some cell types. Such structuring is induced purely by the combination of activity and confinement and is absent in thermal equilibrium. We systematically explore active matter models for chromosomes, discussing how our model can be generalized to study variations in chromosome positioning across different cell types. The approach and model we outline here represent a preliminary attempt towards a quantitative, first-principles description of the large-scale architecture of the cell nucleus.

  5. Active flows on trees

    NASA Astrophysics Data System (ADS)

    Forrow, Aden; Woodhouse, Francis G.; Dunkel, Jörn

    2016-11-01

    Coherent, large scale dynamics in many nonequilibrium physical, biological, or information transport networks are driven by small-scale local energy input. We introduce and explore a generic model for compressible active flows on tree networks. In contrast to thermally-driven systems, active friction selects discrete states with only a small number of oscillation modes activated at distinct fixed amplitudes. This state selection can interact with graph topology to produce different localized dynamical time scales in separate regions of large networks. Using perturbation theory, we systematically predict the stationary states of noisy networks. Our analytical predictions agree well with a Bayesian state estimation based on a hidden Markov model applied to simulated time series data on binary trees. While the number of stable states per tree scales exponentially with the number of edges, the mean number of activated modes in each state averages 1 / 4 the number of edges. More broadly, these results suggest that the macroscopic response of active networks, from actin-myosin networks in cells to flow networks in Physarum polycephalum, can be dominated by a few select modes.

  6. Interpreting EEG alpha activity.

    PubMed

    Bazanova, O M; Vernon, D

    2014-07-01

    Exploring EEG alpha oscillations has generated considerable interest, in particular with regards to the role they play in cognitive, psychomotor, psycho-emotional and physiological aspects of human life. However, there is no clearly agreed upon definition of what constitutes 'alpha activity' or which of the many indices should be used to characterize it. To address these issues this review attempts to delineate EEG alpha-activity, its physical, molecular and morphological nature, and examine the following indices: (1) the individual alpha peak frequency; (2) activation magnitude, as measured by alpha amplitude suppression across the individual alpha bandwidth in response to eyes opening, and (3) alpha "auto-rhythmicity" indices: which include intra-spindle amplitude variability, spindle length and steepness. Throughout, the article offers a number of suggestions regarding the mechanism(s) of alpha activity related to inter and intra-individual variability. In addition, it provides some insights into the various psychophysiological indices of alpha activity and highlights their role in optimal functioning and behavior.

  7. Active thermal cloak

    NASA Astrophysics Data System (ADS)

    Nguyen, Dang Minh; Xu, Hongyi; Zhang, Youming; Zhang, Baile

    2015-09-01

    Thermal cloaking, as an ultimate thermal "illusion" phenomenon, is the result of advanced heat manipulation with thermal metamaterials—heat can be guided around a hidden object smoothly without disturbing the ambient thermal environment. However, all previous thermal metamaterial cloaks were passive devices, lacking the functionality of switching on/off and the flexibility of changing geometries. In this letter, we report an active thermal cloaking device that is controllable. Different from previous thermal cloaking approaches, this thermal cloak adopts active thermoelectric components to "pump" heat from one side to the other side of the hidden object, in a process controlled by input electric voltages. Our work not only incorporates active components in thermal cloaking but also provides controllable functionality in thermal metamaterials that can be used to construct more flexible thermal devices.

  8. Activity Cycles in Stars

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    2009-01-01

    Starspots and stellar activity can be detected in other stars using high precision photometric and spectrometric measurements. These observations have provided some surprises (starspots at the poles - sunspots are rarely seen poleward of 40 degrees) but more importantly they reveal behaviors that constrain our models of solar-stellar magnetic dynamos. The observations reveal variations in cycle characteristics that depend upon the stellar structure, convection zone dynamics, and rotation rate. In general, the more rapidly rotating stars are more active. However, for stars like the Sun, some are found to be inactive while nearly identical stars are found to be very active indicating that periods like the Sun's Maunder Minimum (an inactive period from 1645 to 1715) are characteristic of Sun-like stars.

  9. Antimicrobial activity of spices.

    PubMed

    Arora, D S; Kaur, J

    1999-08-01

    Spices have been shown to possess medicinal value, in particular, antimicrobial activity. This study compares the sensitivity of some human pathogenic bacteria and yeasts to various spice extracts and commonly employed chemotherapeutic substances. Of the different spices tested only garlic and clove were found to possess antimicrobial activity. The bactericidal effect of garlic extract was apparent within 1 h of incubation and 93% killing of Staphylococcus epidermidis and Salmonella typhi was achieved within 3 h. Yeasts were totally killed in 1 h by garlic extract but in 5 h with clove. Some bacteria showing resistance to certain antibiotics were sensitive to extracts of both garlic and clove. Greater anti-candidal activity was shown by garlic than by nystatin. Spices might have a great potential to be used as antimicrobial agents.

  10. PRODUCTS OF ACTIVATED LYMPHOCYTES

    PubMed Central

    Sorg, Clemens; Bloom, Barry R.

    1973-01-01

    General methods were developed and applied to the biosynthesis and purification of products of activated lymphocytes available in minute quantities. The activity studied here was the migration inhibitory factor (MIF) produced by purified protein derivative (PPD)- or concanavalin A (Con A)-stimulated lymphocytes obtained from one guinea pig or less. The methods selected yielded results in terms of two chemical parameters characteristic of the molecules involved, namely Kd on Sephadex G-75 and isoionic point, pI, on isoelectric focusing. When supernatants were fractionated on G-75 columns, there were several areas even in control supernatants which produced migration inhibition relative to medium controls. However, in PPD- and Con A-stimulated supernatants, at least one peak of MIF activity was found solely in the stimulated cultures, with a Kd of 0.15. A double-labeling technique was used to characterize the proteins of this peak. Control, unstimulated cultures were labeled with [14C]leucine and stimulated cultures were labeled with [3H]leucine. After mixing the supernatants and G-75 filtration, a major "ratiolabeled" broad peak. i.e. one with increased 3H/14C ratio, was found. When a narrow portion of this peak about Kd 0.15, containing most of the MIF activity, was subjected to analytical isoelectric focusing, all of the label was associated with proteins of lower net charge than albumin. A unique ratiolabeled peak was found in PPD- and Con A-stimulated fractions with a pI of approx. 5.3. A micropreparative isoelectric focusing technique was developed and yielded MIF activity in the same region as the major ratiolabeled peak. Further study will be required to ascertain whether the ratiolabeled protein is MIF. By following the Kd, pI, and 3H/14C labeling ratio, at least 14 products of activated lymphocytes, synthesized either de novo or in increased amounts, could be distinguished. PMID:4688317

  11. Active cleaning technique device

    NASA Technical Reports Server (NTRS)

    Shannon, R. L.; Gillette, R. B.

    1973-01-01

    The objective of this program was to develop a laboratory demonstration model of an active cleaning technique (ACT) device. The principle of this device is based primarily on the technique for removing contaminants from optical surfaces. This active cleaning technique involves exposing contaminated surfaces to a plasma containing atomic oxygen or combinations of other reactive gases. The ACT device laboratory demonstration model incorporates, in addition to plasma cleaning, the means to operate the device as an ion source for sputtering experiments. The overall ACT device includes a plasma generation tube, an ion accelerator, a gas supply system, a RF power supply and a high voltage dc power supply.

  12. Actively coupled optical waveguides

    NASA Astrophysics Data System (ADS)

    Alexeeva, N. V.; Barashenkov, I. V.; Rayanov, K.; Flach, S.

    2014-01-01

    We consider light propagation through a pair of nonlinear optical waveguides with absorption, placed in a medium with power gain. The active medium boosts the in-phase component of the overlapping evanescent fields of the guides, while the nonlinearity of the guides couples it to the damped out-of-phase component creating a feedback loop. As a result, the structure exhibits stable stationary and oscillatory regimes in a wide range of gain-loss ratios. We show that the pair of actively coupled (AC) waveguides can act as a stationary or integrate-and-fire comparator sensitive to tiny differences in their input powers.

  13. MCO Monitoring activity description

    SciTech Connect

    SEXTON, R.A.

    1998-11-09

    Spent Nuclear Fuel remaining from Hanford's N-Reactor operations in the 1970s has been stored under water in the K-Reactor Basins. This fuel will be repackaged, dried and stored in a new facility in the 200E Area. The safety basis for this process of retrieval, drying, and interim storage of the spent fuel has been established. The monitoring of MCOS in dry storage is a currently identified issue in the SNF Project. This plan outlines the key elements of the proposed monitoring activity. Other fuel stored in the K-Reactor Basins, including SPR fuel, will have other monitoring considerations and is not addressed by this activity description.

  14. Inflammasomes and Their Activation

    PubMed Central

    Khare, Sonal; Luc, Nancy; Dorfleutner, Andrea; Stehlik, Christian

    2011-01-01

    The innate immune system relies on the recognition of pathogens by pattern recognition receptors as a first line of defense and to initiate the adaptive immune response. Substantial progress has been made in defining the role of Nod (nucleotide-binding oligimerization domain)-like receptors and AIM2 (absent in melanoma 2) as pattern recognition receptors that activate inflammasomes in macrophages. Inflammasomes are protein platforms essential for the activation of inflammatory caspases and subsequent maturation of their pro-inflammatory cytokine substrates and induction of pyroptosis. This paper summarizes recent developments regarding the function of Nod-like receptors in immunity and disease. PMID:21083527

  15. Activated carbon material

    DOEpatents

    Evans, A. Gary

    1978-01-01

    Activated carbon particles for use as iodine trapping material are impregnated with a mixture of selected iodine and potassium compounds to improve the iodine retention properties of the carbon. The I/K ratio is maintained at less than about 1 and the pH is maintained at above about 8.0. The iodine retention of activated carbon previously treated with or coimpregnated with triethylenediamine can also be improved by this technique. Suitable flame retardants can be added to raise the ignition temperature of the carbon to acceptable standards.

  16. Antibacterial activity of grepafloxacin.

    PubMed

    Wiedemann, B; Heisig, P

    1997-12-01

    Grepafloxacin has an extremely broad spectrum of activity. Its activity against Gram-positive bacteria exceeds that of currently available quinolones. Grepafloxacin-resistant mutants seem to occur less frequently than ciprofloxacin- or ofloxacin-resistant mutants, and the increase in MIC against the former mutants is less than that of the latter. This applies only to the relative differences (in dilution steps); the absolute values are similar. Grepafloxacin kills Gram-positive bacteria at concentrations little above the MIC. Its pharmacodynamic profile against pneumococci is promising, favouring use of this drug for respiratory tract infections.

  17. Active seismic experiment

    NASA Technical Reports Server (NTRS)

    Kovach, R. L.; Watkins, J. S.; Talwani, P.

    1972-01-01

    The Apollo 16 active seismic experiment (ASE) was designed to generate and monitor seismic waves for the study of the lunar near-surface structure. Several seismic energy sources are used: an astronaut-activated thumper device, a mortar package that contains rocket-launched grenades, and the impulse produced by the lunar module ascent. Analysis of some seismic signals recorded by the ASE has provided data concerning the near-surface structure at the Descartes landing site. Two compressional seismic velocities have so far been recognized in the seismic data. The deployment of the ASE is described, and the significant results obtained are discussed.

  18. Space construction activities

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Center for Space Construction at the University of Colorado at Boulder was established in 1988 as a University Space Engineering Research Center. The mission of the Center is to conduct interdisciplinary engineering research which is critical to the construction of future space structures and systems and to educate students who will have the vision and technical skills to successfully lead future space construction activities. The research activities are currently organized around two central projects: Orbital Construction and Lunar Construction. Summaries of the research projects are included.

  19. Cosmogenic activation of materials

    NASA Astrophysics Data System (ADS)

    Amaré, J.; Beltrán, B.; Capelli, S.; Capozzi, F.; Carmona, J. M.; Cebrián, S.; Cremonesi, O.; García, E.; Irastorza, I. G.; Gómez, H.; Luzón, G.; Martínez, M.; Morales, J.; Ortiz de Solórzano, A.; Pavan, M.; Pobes, C.; Puimedón, J.; Rodríguez, A.; Ruz, J.; Sarsa, M. L.; Torres, L.; Villar, J. A.

    2005-09-01

    The problem of cosmogenic activation produced at sea level in materials typically used in underground experiments looking for rare events is being studied. Several nuclear data libraries have been screened looking for relevant isotope production cross-sections and different codes which can be applied to activation studies have been reviewed. The excitation functions for some problems of interest like production of 60Co and 68Ge in germanium and production of 60Co in tellurium have been obtained taking into account both measurements and calculations and a preliminary estimate of the corresponding rates of production at sea level has been performed.

  20. [Problem Solving Activities.

    ERIC Educational Resources Information Center

    Wisconsin Univ. - Stout, Menomonie. Center for Vocational, Technical and Adult Education.

    The teacher directed problem solving activities package contains 17 units: Future Community Design, Let's Build an Elevator, Let's Construct a Catapult, Let's Design a Recreational Game, Let's Make a Hand Fishing Reel, Let's Make a Wall Hanging, Let's Make a Yo-Yo, Marooned in the Past, Metrication, Mousetrap Vehicles, The Multi System…

  1. [Biological activity of Spirulina].

    PubMed

    Blinkova, L P; Gorobets, O B; Baturo, A P

    2001-01-01

    In this review information of Spirulina platensis (SP), a blue-green alga (photosynthesizing cyanobacterium) having diverse biological activity is presented. Due to high content of highly valuable proteins, indispensable amino acids, vitamins, beta-carotene and other pigments, mineral substances, indispensable fatty acids and polysaccharides, PS has been found suitable for use as bioactive additive. SP produces an immunostimulating effect by enhancing the resistance of humans, mammals, chickens and fish to infections, the capacity of influencing hemopoiesis, stimulating the production of antibodies and cytokines. Under the influence of SP macrophages, T and B cells are activated. SP sulfolipids have proved to be effective against HIV. Preparations obtained from SP biomass have also been found active against herpesvirus, cytomegalovirus, influenza virus, etc. SP extracts are capable in inhibiting cancerogenesis. SP preparations are regarded as functional products contributing to the preservation of the resident intestinal microflora, especially lactic acid bacilli and bifidobacteria, and to a decrease in the level of Candida albicans. The biological activity of SP with respect to microorganisms holds good promise for using these microalgae as components of culture media.

  2. Active Authentication: Beyond Passwords

    DTIC Science & Technology

    2011-11-18

    semantic analysis (how you construct sentences); Forensic authorship Keystroke pattern; Mouse movement Fingerprint ; Iris pattern; Vein...Solutions Physiological Biometrics Sensors tracking the physical attributes of you • DNA • Ear Geometry • Facial Geometry • Fingerprint • Iris...Preview Fingerprint Forensic authorship2 Mouse tracking1 How you behave Physical aspects of you The context you exist in • The Active Authentication

  3. An Active Attraction.

    ERIC Educational Resources Information Center

    Burns, Joseph C.; Buzzelli, Cary

    1992-01-01

    Describes a unit on magnetism that utilizes hands-on activities in which students make hypotheses for discrepant behavior, discover whether a magnet attracts one object through another, measure the strength of magnets, explore levitating paper clips, and play a game dependent on magnetic attraction. (MDH)

  4. Active control system trends

    NASA Technical Reports Server (NTRS)

    Yore, E. E.; Gunderson, D. C.

    1976-01-01

    The active control concepts which achieve the benefit of improved mission performance and lower cost and generate system trends towards improved dynamic performance, more integration, and digital fly by wire mechanization are described. Analytical issues and implementation requirements and tools and approaches developed to address the analytical and implementation issues are briefly discussed.

  5. Arsenic activation neutron detector

    DOEpatents

    Jacobs, Eddy L.

    1981-01-01

    A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5 Mev neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

  6. Arsenic activation neutron detector

    DOEpatents

    Jacobs, E.L.

    1980-01-28

    A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5-MeV neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

  7. Earthfest. Activity Book.

    ERIC Educational Resources Information Center

    Weilbacher, Mike

    1991-01-01

    An activity book to help elementary teachers and students explore the environment offers information and questions about spaceships; an ecology primer and poster with questions; information on animal adaptation with poster and questions; ecological and dramatic arts projects; a script for performance; and suggestions to make Earth Day celebrations…

  8. Regional Activities Division. Papers.

    ERIC Educational Resources Information Center

    International Federation of Library Associations, The Hague (Netherlands).

    Papers on library network activities in Canada, the Third World, Japan, Malaysia, Brazil, and Sweden which were presented at the 1982 International Federation of Library Associations (IFLA) conference include: (1) "Canada: A Voluntary and Flexible Network," a review by Guy Sylvestre of the political, social, and economic structures…

  9. Learning Activity Package, Algebra.

    ERIC Educational Resources Information Center

    Evans, Diane

    A set of ten teacher-prepared Learning Activity Packages (LAPs) in beginning algebra and nine in intermediate algebra, these units cover sets, properties of operations, number systems, open expressions, solution sets of equations and inequalities in one and two variables, exponents, factoring and polynomials, relations and functions, radicals,…

  10. Educating for Political Activity

    ERIC Educational Resources Information Center

    Chitty, Clyde

    2010-01-01

    The term "political activity" can be interpreted in a myriad of different ways, but in this paper, it is taken to mean involvement in a variety of campaigns around issues affecting the way we live and the sort of society we want to live in. At a time when support for the main political parties has never been weaker, it is essential that…

  11. Active microwave water equivalence

    NASA Technical Reports Server (NTRS)

    Boyne, H. S.; Ellerbruch, D. A.

    1980-01-01

    Measurements of water equivalence using an active FM-CW microwave system were conducted over the past three years at various sites in Colorado, Wyoming, and California. The measurement method is described. Measurements of water equivalence and stratigraphy are compared with ground truth. A comparison of microwave, federal sampler, and snow pillow measurements at three sites in Colorado is described.

  12. Active Learning Methods

    ERIC Educational Resources Information Center

    Zayapragassarazan, Z.; Kumar, Santosh

    2012-01-01

    Present generation students are primarily active learners with varied learning experiences and lecture courses may not suit all their learning needs. Effective learning involves providing students with a sense of progress and control over their own learning. This requires creating a situation where learners have a chance to try out or test their…

  13. Bonus Activity Book.

    ERIC Educational Resources Information Center

    Learning, 1993

    1993-01-01

    Elementary level activity book presents suggestions for teaching students about endangered and threatened species worldwide. Students learn about what is causing the rapid extinction rate and what needs to be done. They also discover the value of rainforests and why conservationists are fighting to save them. (SM)

  14. Macrophage activation and polarization.

    PubMed

    Martinez, Fernando Oneissi; Sica, Antonio; Mantovani, Alberto; Locati, Massimo

    2008-01-01

    Macrophages are widely distributed immune system cells that play an indispensable role in homeostasis and defense. They can be phenotypically polarized by the microenvironment to mount specific functional programs. Polarized macrophages can be broadly classified in two main groups: classically activated macrophages (or M1), whose prototypical activating stimuli are IFNgamma and LPS, and alternatively activated macrophages (or M2), further subdivided in M2a (after exposure to IL-4 or IL-13), M2b (immune complexes in combination with IL-1beta or LPS) and M2c (IL-10, TGFbeta or glucocorticoids). M1 exhibit potent microbicidal properties and promote strong IL-12-mediated Th1 responses, whilst M2 support Th2-associated effector functions. Beyond infection M2 polarized macrophages play a role in resolution of inflammation through high endocytic clearance capacities and trophic factor synthesis, accompanied by reduced pro-inflammatory cytokine secretion. Similar functions are also exerted by tumor-associated macrophages (TAM), which also display an alternative-like activation phenotype and play a detrimental pro-tumoral role. Here we review the main functions of polarized macrophages and discuss the perspectives of this field.

  15. Active Ingredient - AZ

    EPA Pesticide Factsheets

    EPA Pesticide Chemical Search allows a user to easily find the pesticide chemical or active ingredient that they are interested in by using an array of simple to advanced search options. Chemical Search provides a single point of reference for easy access to information previously published in a variety of locations, including various EPA web pages and Regulations.gov.

  16. Shark Tagging Activities.

    ERIC Educational Resources Information Center

    Current: The Journal of Marine Education, 1998

    1998-01-01

    In this group activity, children learn about the purpose of tagging and how scientists tag a shark. Using a cut-out of a shark, students identify, measure, record data, read coordinates, and tag a shark. Includes introductory information about the purpose of tagging and the procedure, a data sheet showing original tagging data from Tampa Bay, and…

  17. Engineers and Active Responsibility.

    PubMed

    Pesch, Udo

    2015-08-01

    Knowing that technologies are inherently value-laden and systemically interwoven with society, the question is how individual engineers can take up the challenge of accepting the responsibility for their work? This paper will argue that engineers have no institutional structure at the level of society that allows them to recognize, reflect upon, and actively integrate the value-laden character of their designs. Instead, engineers have to tap on the different institutional realms of market, science, and state, making their work a 'hybrid' activity combining elements from the different institutional realms. To deal with this institutional hybridity, engineers develop routines and heuristics in their professional network, which do not allow societal values to be expressed in a satisfactory manner. To allow forms of 'active' responsibility, there have to be so-called 'accountability forums' that guide moral reflections of individual actors. The paper will subsequently look at the methodologies of value-sensitive design (VSD) and constructive technology assessment (CTA) and explore whether and how these methodologies allow engineers to integrate societal values into the design technological artifacts and systems. As VSD and CTA are methodologies that look at the process of technological design, whereas the focus of this paper is on the designer, they can only be used indirectly, namely as frameworks which help to identify the contours of a framework for active responsibility of engineers.

  18. Activities: Visualization, Estimation, Computation.

    ERIC Educational Resources Information Center

    Maletsky, Evan M.

    1982-01-01

    The material is designed to help students build a cone model, visualize how its dimensions change as its shape changes, estimate maximum volume position, and develop problem-solving skills. Worksheets designed for duplication for classroom use are included. Part of the activity involves student analysis of a BASIC program. (MP)

  19. Intermittent Activity in AGN

    NASA Astrophysics Data System (ADS)

    Janiuk, A.; Czerny, B.; Siemiginowska, A.

    2004-10-01

    There is a growing evidence that the AGN activity could be intermittent. It remains an open question if this behavior is caused by changes in the fuel sup- ply to the supermassive black hole from the large distances, or rather by a processes intrinsic to the active nucleus. We consider the possibility that ac- cretion onto a supermassive black hole is controlled by an accretion disk which is subject to the hydro- gen ionization instability. This drives the observed on-off activity cycle, since periodically the accretion flow becomes inefficient and the disk goes to quies- cence. We consider effects of the MHD turbulence on the viscosity during the evolution of a standard α - disk. We perform a self-consistency check of the α de- scription of the angular momentum transfer. Hav- ing shown that the viscosity parameter is constant throughout the whole instability cycle, as implied by the strength of the MHD turbulence, we calcu- late the time evolution of the disk under the influ- ence of the ionization instability. We demonstrate that if the accretion onto a supermassive black hole proceeds through an outer standard accretion disk and inner, radiatively inefficient and advection dom- inated flow, the modelled amplitudes of disk lumi- nosity variations are sufficiently high to account for the observations. Key words: accretion disks; galaxies: active.

  20. Highlights of 1976 activities

    NASA Technical Reports Server (NTRS)

    Fitzpatrick, M.

    1976-01-01

    Highlights of NASA's 1976 activities are summarized. Sixteen successful launches were made. Two landings of Viking spacecraft on Mars and rollout of the space shuttle orbiter are reviewed. Applications of aerospace science to education, health care, and community services are also discussed.

  1. Activities from Asia.

    ERIC Educational Resources Information Center

    Texas Child Care, 1995

    1995-01-01

    Notes that the best way to learn about another culture is to know how its habits, traditions, and environments differ from or resemble our own. Provides several activities to help young children understand Asian cultures, including cooking, origami, and games and festivals. (HTH)

  2. Highlights of 1978 activities

    NASA Technical Reports Server (NTRS)

    1978-01-01

    General highlights of NASA's activities for 1978 are presented. The highlights are categorized into topics such as space science, space transportation systems, space and terrestrial applications, environment, technology utilization, aeronautics, space research and technology, energy programs, and international. A list of the 1978 launches including: (1) launch date; (2) payload designation; (3) launch vehicle; (4) launch site and (5) mission remarks is also presented.

  3. Multidisciplinary Wildlife Teaching Activities.

    ERIC Educational Resources Information Center

    Hernbrode, William R., Ed.

    This guide provides information and activities descriptions designed to allow the teacher to use wildlife concepts in the teaching of various subjects. The author suggests that wildlife and animals are tremendous motivators for children and hold their attention. In the process, concepts of wildlife interaction with man and the environment are…

  4. Active-bridge oscillator

    DOEpatents

    Wessendorf, Kurt O.

    2001-01-01

    An active bridge oscillator is formed from a differential amplifier where positive feedback is a function of the impedance of one of the gain elements and a relatively low value common emitter resistance. This use of the nonlinear transistor parameter h stabilizes the output and eliminates the need for ALC circuits common to other bridge oscillators.

  5. Immunizations: Active vs. Passive

    MedlinePlus

    ... a certain type of wild animal bites a child. Passive immunizations for hepatitis A (gamma globulin) may be helpful ... A is common. They are typically given before children or adults leave on their ... active vaccination is preferable. Keep in mind that passive immunizations ...

  6. 85 Engaging Movement Activities.

    ERIC Educational Resources Information Center

    Weikart, Phyllis S.; Carlton, Elizabeth B.

    This book presents activities to keep K-6 students moving in a variety of ways as they learn. The movement experiences are planned around key curriculum concepts in movement and music as well as in academic curriculum areas. The experiences develop students' basic timing, language abilities, vocabulary, concentration, planning skills, and…

  7. Classification of Physical Activity

    PubMed Central

    Turksoy, Kamuran; Paulino, Thiago Marques Luz; Zaharieva, Dessi P.; Yavelberg, Loren; Jamnik, Veronica; Riddell, Michael C.; Cinar, Ali

    2015-01-01

    Physical activity has a wide range of effects on glucose concentrations in type 1 diabetes (T1D) depending on the type (ie, aerobic, anaerobic, mixed) and duration of activity performed. This variability in glucose responses to physical activity makes the development of artificial pancreas (AP) systems challenging. Automatic detection of exercise type and intensity, and its classification as aerobic or anaerobic would provide valuable information to AP control algorithms. This can be achieved by using a multivariable AP approach where biometric variables are measured and reported to the AP at high frequency. We developed a classification system that identifies, in real time, the exercise intensity and its reliance on aerobic or anaerobic metabolism and tested this approach using clinical data collected from 5 persons with T1D and 3 individuals without T1D in a controlled laboratory setting using a variety of common types of physical activity. The classifier had an average sensitivity of 98.7% for physiological data collected over a range of exercise modalities and intensities in these subjects. The classifier will be added as a new module to the integrated multivariable adaptive AP system to enable the detection of aerobic and anaerobic exercise for enhancing the accuracy of insulin infusion strategies during and after exercise. PMID:26443291

  8. Production Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Gallaway, Ann, Ed.

    This production systems guide provides teachers with learning activities for secondary students. Introductory materials include an instructional planning outline and worksheet, an outline of essential elements, domains and objectives, a course description, and a content outline. The guide contains 30 modules on the following topics: production…

  9. Dissemination Activities Report

    ERIC Educational Resources Information Center

    Barclay, Hanna; Batatia, Hudj; Bauters, Merja; Ben Ami, Zvi; Drachman, Raul; Flouris, Giorgos; Jadin, Tanja; Jalonen, Satu; Karlgren, Klas; Karpati, Andrea; Kotzinos, Dimitris; Lakkala, Minna; Lallimo, Jiri; Moen, Anne; Nygard, Kathrine; Paavola, Sami; Padiglia, Sheila; Scapolla, Marina; Sins, Patrick; Vasileva, Tania

    2008-01-01

    In the first 24 months of the project, KP-Lab members were highly dedicated to dissemination and were engaged in various dissemination activities that contributed to the prime objective of the KP-Lab dissemination efforts which is "to make the project widely known to a variety of prospective users and, at a later stage, to promote the…

  10. Designing Metacognitive Activities.

    ERIC Educational Resources Information Center

    Lin, Xiaodong

    2001-01-01

    Proposes a framework for thinking about how metacognition research might apply to design activities. Examines two basic approaches to supporting metacognition: strategy training, and creation of a supportive social environment for metacognition. Identifies two kinds of content that are taught using these two approaches: knowledge about a specific…

  11. Geology: The Active Earth.

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1987-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. The topic of this issue is "Geology: The Active Earth." Contents are organized into the…

  12. Marketing coprovided activities.

    PubMed

    Dickerson, Pamela S

    2014-05-01

    Coproviding is a wonderful way for two or more organizations to work together to provide continuing nursing education. To be transparent to the learners, marketing materials identify the parties involved and prominently note the name of the organization accountable for developing the activity and awarding the contact hours.

  13. Communication Systems. Laboratory Activities.

    ERIC Educational Resources Information Center

    Sutherland, Barbara, Ed.

    This communication systems guide provides teachers with learning activities for secondary students. Introductory materials include an instructional planning outline and worksheet, an outline of essential elements, a list of objectives, a course description, and a content outline. The guide contains 32 modules on the following topics: story…

  14. Chaperone activation by unfolding.

    PubMed

    Foit, Linda; George, Jenny S; Zhang, Bin W; Brooks, Charles L; Bardwell, James C A

    2013-04-02

    Conditionally disordered proteins can alternate between highly ordered and less ordered configurations under physiological conditions. Whereas protein function is often associated with the ordered conformation, for some of these conditionally unstructured proteins, the opposite applies: Their activation is associated with their unfolding. An example is the small periplasmic chaperone HdeA, which is critical for the ability of enteric bacterial pathogens like Escherichia coli to survive passage through extremely acidic environments, such as the human stomach. At neutral pH, HdeA is a chaperone-inactive dimer. On a shift to low pH, however, HdeA monomerizes, partially unfolds, and becomes rapidly active in preventing the aggregation of substrate proteins. By mutating two aspartic acid residues predicted to be responsible for the pH-dependent monomerization of HdeA, we have succeeded in isolating an HdeA mutant that is active at neutral pH. We find this HdeA mutant to be substantially destabilized, partially unfolded, and mainly monomeric at near-neutral pH at a concentration at which it prevents aggregation of a substrate protein. These results provide convincing evidence for direct activation of a protein by partial unfolding.

  15. Ocean Drilling Simulation Activity.

    ERIC Educational Resources Information Center

    Telese, James A.; Jordan, Kathy

    The Ocean Drilling Project brings together scientists and governments from 20 countries to explore the earth's structure and history as it is revealed beneath the oceans' basins. Scientific expeditions examine rock and sediment cores obtained from the ocean floor to learn about the earth's basic processes. The series of activities in this…

  16. Organizing Preservation Activities.

    ERIC Educational Resources Information Center

    Cloonan, Michele

    This resource guide considers issues in the staffing and organization of preservation activities. It provides guidance in implementing a systematic preservation program and evaluates the structures of various types of preservation programs. The following articles complement the discussion of program models and implementation: (1)…

  17. Activities: Some Colorful Mathematics.

    ERIC Educational Resources Information Center

    DeTemple, Duane W.; Walker, Dean A.

    1996-01-01

    Describes three activities in discrete mathematics that involve coloring geometric objects: counting colored regions of overlapping simple closed curves, counting colored triangulations of polygons, and determining the number of colors required to paint the plane so that no two points one inch apart are the same color. (MKR)

  18. Physical Activities for Preschool.

    ERIC Educational Resources Information Center

    Adkins, Dorothy C.; And Others

    The underlying premise of the University of Hawaii Physical Activities for Preschool curriculum is that important contributions to a positive self-concept are made by motor independence and a realistic body image. Program objectives include: (1) the development of strength, endurance, and flexibility in skills that involve the muscles,…

  19. Activating silent argonautes.

    PubMed

    Kidwell, Mary Anne; Doudna, Jennifer A

    2013-07-01

    Multiple Argonaute proteins are implicated in gene silencing by RNA interference (RNAi), but only one is known to be an endonuclease that can cleave target mRNAs. Chimeric Argonaute proteins now reveal an unexpected mechanism by which mutations distal to the catalytic center can unmask intrinsic catalytic activity, results hinting at structurally mediated regulation.

  20. Commission 10: Solar Activity

    NASA Astrophysics Data System (ADS)

    van Driel-Gesztelyi, Lidia; Schrijver, Carolus J.; Klimchuk, James A.; Charbonneau, Paul; Fletcher, Lyndsay; Hasan, S. Sirajul; Hudson, Hugh S.; Kusano, Kanya; Mandrini, Cristina H.; Peter, Hardi; Vršnak, Bojan; Yan, Yihua

    2012-04-01

    Commission 10 of the International Astronomical Union has more than 650 members who study a wide range of activity phenomena produced by our nearest star, the Sun. Solar activity is intrinsically related to solar magnetic fields and encompasses events from the smallest energy releases (nano- or even picoflares) to the largest eruptions in the Solar System, coronal mass ejections (CMEs), which propagate into the Heliosphere reaching the Earth and beyond. Solar activity is manifested in the appearance of sunspot groups or active regions, which are the principal sources of activity phenomena from the emergence of their magnetic flux through their dispersion and decay. The period 2008-2009 saw an unanticipated extended solar cycle minimum and unprecedentedly weak polar-cap and heliospheric field. Associated with that was the 2009 historical maximum in galactic cosmic rays flux since measurements begun in the middle of the 20th Century. Since then Cycle 24 has re-started solar activity producing some spectacular eruptions observed with a fleet of spacecraft and ground-based facilities. In the last triennium major advances in our knowledge and understanding of solar activity were due to continuing success of space missions as SOHO, Hinode, RHESSI and the twin STEREO spacecraft, further enriched by the breathtaking images of the solar atmosphere produced by the Solar Dynamic Observatory (SDO) launched on 11 February 2010 in the framework of NASA's Living with a Star program. In August 2012, at the time of the IAU General Assembly in Beijing when the mandate of this Commission ends, we will be in the unique position to have for the first time a full 3-D view of the Sun and solar activity phenomena provided by the twin STEREO missions about 120 degrees behind and ahead of Earth and other spacecraft around the Earth and ground-based observatories. These new observational insights are continuously posing new questions, inspiring and advancing theoretical analysis and

  1. 45 CFR 1226.8 - Prohibited activities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SERVICE PROHIBITIONS ON ELECTORAL AND LOBBYING ACTIVITIES Volunteer Activities § 1226.8 Prohibited activities. (a) Electoral Activity. Volunteers shall not engage in any activity which may, directly...

  2. Interdisciplinary Astronomy Activities

    NASA Astrophysics Data System (ADS)

    Nerantzis, Nikolaos; Mitrouda, Aikaterini; Reizopoulou, Ioanna; Sidiropoulou, Eirini; Hatzidimitriou, Antonios

    2016-04-01

    On November 9th, 2015, three didactical hours were dedicated to Interdisciplinary Astronomy Activities (http://wp.me/p6Hte2-1I). Our students and their teachers formed three groups and in rotation, were engaged with the following activities: (a) viewing unique images of the Cosmos in the mobile planetarium STARLAB (http://www.planitario.gr/tholos-starlab-classic-standard.html), (b) watching the following videos: Journey to the end of the universe (https://youtu.be/Ufl_Nwbl8xs), Rosetta update (https://youtu.be/nQ9ivd7wv30), The Solar System (https://youtu.be/d66dsagrTa0), Ambition the film (https://youtu.be/H08tGjXNHO4) in the school's library. Students and teachers were informed about our solar system, the Rosetta mission, the universe, etc. and (c) tactile activities such as Meet our home and Meet our neighbors (http://astroedu.iau.org, http://nuclio.org/astroneighbours/resources) and the creation of planets' 3D models (Geology-Geography A' Class Student's book, pg.15). With the activities above we had the pleasure to join the Cosmic Light Edu Kit / International Year of Light 2015 program. After our Interdisciplinary Astronomy Activities, we did a "small" research: our students had to fill an evaluation about their educational gains and the results can be found here http://wp.me/p6Hte2-2q. Moreover, we discussed about Big Ideas of Science (http://wp.me/p3oRiZ-dm) and through the "big" impact of the Rosetta mission & the infinity of our universe, we print posters with relevant topics and place them to the classrooms. We thank Rosa Doran (Nuclio - President of the Executive Council) for her continuous assistance and support on innovative science teaching proposals. She is an inspiration.

  3. Activities. Inductive and Deductive Reasoning.

    ERIC Educational Resources Information Center

    O'Daffer, Phares G.; And Others

    1990-01-01

    Provided are the activity sheets for students and the teaching guide for this middle school geometry activity. Materials, prerequisites, objectives, and procedures are listed. Extension activities are suggested. An answer key is included. (CW)

  4. 101 Environmental Education Activities. Booklet 6--Social Studies Activities.

    ERIC Educational Resources Information Center

    Whitney, Helen, Comp.

    Based on the environment and directed at elementary and intermediate level students, 5 field trips are a significant part of the 12 social studies activities in the sixth booklet by the Upper Mississippi River ECO-Center outlining environmental and outdoor education activities. Most of the activities include objectives, activity description,…

  5. Integration of Active Video Games in Extracurricular Activity at Schools

    ERIC Educational Resources Information Center

    Lee, Jung Eun; Huang, Charles; Pope, Zachary; Gao, Zan

    2015-01-01

    Active video games require players to be physically active. Dance Dance Revolution (DDR) is an interactive dancing game that requires fast-foot movement coordinated with energetic music and visuals. The Wii and Xbox Kinect games have also become good active video games for the promotion of physical activity participation. These games are much more…

  6. Is Enhanced Physical Activity Possible Using Active Videogames?

    PubMed

    Baranowski, Tom; Baranowski, Janice; O'Connor, Teresia; Lu, Amy Shirong; Thompson, Debbe

    2012-06-01

    Our research indicated that 10-12-year-old children receiving two active Wii(™) (Nintendo(®); Nintendo of America, Inc., Redmond, WA) console videogames were no more physically active than children receiving two inactive videogames. Research is needed on how active videogames may increase physical activity.

  7. Active braze process

    SciTech Connect

    Levine, I.L.; Pike, R.A.

    1990-11-02

    Active metal bonding using Cusil (silver-copper) braze alloys is a well established method used at GE Neutron Devices (GEND) for bonding metal to metal, metal to ceramics, and ceramics to ceramics. However, there are many instances in which using a silver alloy for bonding is undesirable (e.g., in vacuum tube envelopes, or where sequential braze steps at different temperatures are required to complete an assembly). The Material and Processes Laboratory at GEND has discovered a new method of active brazing with non-silver alloys which has proved especially successful in ceramic-to-ceramic joints. This method has the added advantage of eliminating several steps which are required in conventional bonding techniques. 2 figs., 10 tabs.

  8. Myofilament length dependent activation.

    PubMed

    de Tombe, Pieter P; Mateja, Ryan D; Tachampa, Kittipong; Ait Mou, Younss; Farman, Gerrie P; Irving, Thomas C

    2010-05-01

    The Frank-Starling law of the heart describes the interrelationship between end-diastolic volume and cardiac ejection volume, a regulatory system that operates on a beat-to-beat basis. The main cellular mechanism that underlies this phenomenon is an increase in the responsiveness of cardiac myofilaments to activating Ca(2+) ions at a longer sarcomere length, commonly referred to as myofilament length-dependent activation. This review focuses on what molecular mechanisms may underlie myofilament length dependency. Specifically, the roles of inter-filament spacing, thick and thin filament based regulation, as well as sarcomeric regulatory proteins are discussed. Although the "Frank-Starling law of the heart" constitutes a fundamental cardiac property that has been appreciated for well over a century, it is still not known in muscle how the contractile apparatus transduces the information concerning sarcomere length to modulate ventricular pressure development.

  9. Mount Erebus activity

    NASA Astrophysics Data System (ADS)

    An international team of scientists reports that unusually high seismic activity joggled Mount Erebus last fall. However, the Antarctic volcano showed no external signs of an eruption.When scientists from the United States, Japan, and New Zealand returned to the world's southernmost active volcano last November for their annual field expedition, they found that seismic stations recorded 650 small tremors on October 8; prior to that, the number of quakes had averaged between 20 and 80 per day. The October 8 maximum was followed by 140 on October 9 and 120 on October 10. Philip R. Kyle, assistant professor of geochemistry at the New Mexico Institute of Mining and Technology in Socorro and leader of the team studying Mount Erebus, noted that some of the strongest earthquakes recorded during the team's 3 years of observations occurred on October 8; these registered less than 2 on the Richter scale.

  10. UNESCO's activities in ethics.

    PubMed

    ten Have, Henk A M J

    2010-03-01

    UNESCO is an intergovernmental organization with 193 Member States. It is concerned with a broad range of issues regarding education, science and culture. It is the only UN organisation with a mandate in science. Since 1993 it is addressing ethics of science and technology, with special emphasis on bioethics. One major objective of the ethics programme is the development of international normative standards. This is particularly important since many Member States only have a limited infrastructure in bioethics, lacking expertise, educational programs, bioethics committees and legal frameworks. UNESCO has recently adopted the Universal Declaration on Bioethics and Human Rights. The focus of current activities is now on implementation of this Declaration. Three activities are discussed that aim at improving and reinforcing the ethics infrastructure in relation to science and technology: the Global Ethics Observatory, the Ethics Education Programme and the Assisting Bioethics Committees project.

  11. LANSCE Activity Report

    SciTech Connect

    Amy Robinson; Audrey Archuleta; Barbara Maes; Dan Strottman; Earl Hoffman; Garth Tietjen; Gene Farnum; Geoff Greene; Joyce Roberts; Ken Johnson; Paul Lewis; Roger Pynn; Stan Schriber; Steve Sterbenz; Steve Wender; Sue Harper

    1999-02-01

    The Los Alamos Neutron Science Center Activity Report describes scientific and technological progress and achievements in LANSCE Division during the period of 1995 to 1998. This report includes a message from the Division Director, an overview of LANSCE, sponsor overviews, research highlights, advanced projects and facility upgrades achievements, experimental and user program accomplishments, news and events, and a list of publications. The research highlights cover the areas of condensed-matter science and engineering, accelerator science, nuclear science, and radiography. This report also contains a compact disk that includes an overview, the Activity Report itself, LANSCE operations progress reports for 1996 and 1997, experiment reports from LANSCE users, as well as a search capability.

  12. Myofilament length dependent activation

    SciTech Connect

    de Tombe, Pieter P.; Mateja, Ryan D.; Tachampa, Kittipong; Mou, Younss Ait; Farman, Gerrie P.; Irving, Thomas C.

    2010-05-25

    The Frank-Starling law of the heart describes the interrelationship between end-diastolic volume and cardiac ejection volume, a regulatory system that operates on a beat-to-beat basis. The main cellular mechanism that underlies this phenomenon is an increase in the responsiveness of cardiac myofilaments to activating Ca{sup 2+} ions at a longer sarcomere length, commonly referred to as myofilament length-dependent activation. This review focuses on what molecular mechanisms may underlie myofilament length dependency. Specifically, the roles of inter-filament spacing, thick and thin filament based regulation, as well as sarcomeric regulatory proteins are discussed. Although the 'Frank-Starling law of the heart' constitutes a fundamental cardiac property that has been appreciated for well over a century, it is still not known in muscle how the contractile apparatus transduces the information concerning sarcomere length to modulate ventricular pressure development.

  13. Techniques for active passivation

    SciTech Connect

    Roscioli, Joseph R.; Herndon, Scott C.; Nelson, Jr., David D.

    2016-12-20

    In one embodiment, active (continuous or intermittent) passivation may be employed to prevent interaction of sticky molecules with interfaces inside of an instrument (e.g., an infrared absorption spectrometer) and thereby improve response time. A passivation species may be continuously or intermittently applied to an inlet of the instrument while a sample gas stream is being applied. The passivation species may have a highly polar functional group that strongly binds to either water or polar groups of the interfaces, and once bound presents a non-polar group to the gas phase in order to prevent further binding of polar molecules. The instrument may be actively used to detect the sticky molecules while the passivation species is being applied.

  14. Nematicidal activity of terpenoids.

    PubMed

    Abdel-Rahman, Fawzia H; Alaniz, Nina M; Saleh, Mahmoud A

    2013-01-01

    Thirty four phytoterpenoids were evaluated for their nematicidal effect using the model nematode Caenorhabditis elegans. Nematicidal activities of the tested compounds at concentrations of 50 μg/mL showed wide variation in their effects ranging from no effect, weak, moderate and strong effects. Terpenoids exerting 50% or higher mortality at 50 μg/mL were further tested at five different concentrations to calculate the concentration that will kill 50% of the nematode population (LC(50)). Among the most effective terpenoids were carvacrol, thymol, nerolidol, α-terpinene, geraniol, citronellol, farnesol, limonene, pseudoionone and eugenol in a descending order. These compounds exhibited a dose-dependent effect. The results suggest that the selected monoterpenoids and essential oils with a high concentration of these compounds mayprovide potential natural nematicides and merit further study as botanical nematicides for the control of both plant and animal parasitic nematodes. In general, oxygenated terpenoids and phenolic terpenoids exhibited higher nematicidal activity than hydrocarbons terpenoids.

  15. Active region seismology

    NASA Technical Reports Server (NTRS)

    Bogdan, Tom; Braun, D. C.

    1995-01-01

    Active region seismology is concerned with the determination and interpretation of the interaction of the solar acoustic oscillations with near-surface target structures, such as magnetic flux concentration, sunspots, and plage. Recent observations made with a high spatial resolution and a long temporal duration enabled measurements of the scattering matrix for sunspots and solar active regions to be carried out as a function of the mode properties. Based on this information, the amount of p-mode absorption, partial-wave phase shift, and mode mixing introduced by the sunspot, could be determined. In addition, the possibility of detecting the presence of completely submerged magnetic fields was raised, and new procedures for performing acoustic holography of the solar interior are being developed. The accumulating evidence points to the mode conversion of p-modes to various magneto-atmospheric waves within the magnetic flux concentration as being the unifying physical mechanism responsible for these diverse phenomena.

  16. Cisplatin triggers platelet activation.

    PubMed

    Togna, G I; Togna, A R; Franconi, M; Caprino, L

    2000-09-01

    Clinical observations suggest that anticancer drugs could contribute to the thrombotic complications of malignancy in treated patients. Thrombotic microangiopathy, myocardial infarction, and cerebrovascular thrombotic events have been reported for cisplatin, a drug widely used in the treatment of many solid tumours. The aim of this study is to explore in vitro cisplatin effect on human platelet reactivity in order to define the potentially active role of platelets in the pathogenesis of cisplatin-induced thrombotic complications. Our results demonstrate that cisplatin increases human platelet reactivity (onset of platelet aggregation wave and thromboxane production) to non-aggregating concentrations of the agonists involving arachidonic acid metabolism. Direct or indirect activation of platelet phospholipase A(2) appears to be implicated. This finding contributes to a better understanding of the pathogenesis of thrombotic complications occurring during cisplatin-based chemotherapy.

  17. Active optical zoom system.

    PubMed

    Wang, Di; Wang, Qiong-Hua; Shen, Chuan; Zhou, Xin; Liu, Chun-Mei

    2014-11-01

    In this work, we propose an active optical zoom system. The zoom module of the system is formed by a liquid lens and a spatial light modulator (SLM). By controlling the focal lengths of the liquid lens and the encoded digital lens on the SLM panel, we can change the magnification of an image without mechanical moving parts and keep the output plane stationary. The magnification can change from 1/3 to 3/2 as the focal length of the encoded lens on the SLM changes from infinity to 24 cm. The proposed active zoom system is simple and flexible, and has widespread application in optical communications, imaging systems, and displays.

  18. Active microchannel heat exchanger

    DOEpatents

    Tonkovich, Anna Lee Y [Pasco, WA; Roberts, Gary L [West Richland, WA; Call, Charles J [Pasco, WA; Wegeng, Robert S [Richland, WA; Wang, Yong [Richland, WA

    2001-01-01

    The present invention is an active microchannel heat exchanger with an active heat source and with microchannel architecture. The microchannel heat exchanger has (a) an exothermic reaction chamber; (b) an exhaust chamber; and (c) a heat exchanger chamber in thermal contact with the exhaust chamber, wherein (d) heat from the exothermic reaction chamber is convected by an exothermic reaction exhaust through the exhaust chamber and by conduction through a containment wall to the working fluid in the heat exchanger chamber thereby raising a temperature of the working fluid. The invention is particularly useful as a liquid fuel vaporizer and/or a steam generator for fuel cell power systems, and as a heat source for sustaining endothermic chemical reactions and initiating exothermic reactions.

  19. Environmental health program activities

    NASA Technical Reports Server (NTRS)

    Bergtholdt, C. P.

    1969-01-01

    Activities reported include studies on toxic air contaminants, excessive noise, poor lighting, food sanitation, water pollution, and exposure to nonionizing radiation as health hazards. Formulations for a radiological health manual provide guidance to personnel in the procurement and safe handling of radiation producing equipment and Apollo mission planning. A literature search and development of a water analysis laboratory are outlined to obtain information regarding microbiological problems involving potable water, waste management, and personal hygiene.

  20. [Chronotropic activity of semax].

    PubMed

    Arushanian, E B; Popov, A V

    2008-01-01

    The chronic administration of nootropic drug Semax, a peptide analog of ACTH (4-10), normalized the circadian locomotor rhythm in rats (with an increase in its amplitude, a shift in the acrophase, and a change of the spectral characteristics) and reduced the integral chronobiological index. It is suggested that the rhythm-synchronizing chronotropic activity may be a part of the specific effect of this cognitive enhancer.

  1. Imaging nervous system activity.

    PubMed

    Fields, Douglas R; Shneider, Neil; Mentis, George Z; O'Donovan, Michael J

    2009-10-01

    This unit describes methods for loading ion- and voltage-sensitive dyes into neurons, with a particular focus on the spinal cord as a model system. In addition, we describe the use of these dyes to visualize neural activity. Although the protocols described here concern spinal networks in culture or an intact in vitro preparation, they can be, and have been, widely used in other parts of the nervous system.

  2. Assay of FAAH Activity.

    PubMed

    Bari, Monica; Feole, Monica; Maccarrone, Mauro

    2016-01-01

    Fatty acid amide hydrolase (FAAH) is an intracellular enzyme responsible for the hydrolysis of endogenous anandamide (AEA), a reaction that terminates the biological effects of this lipid mediator. The final products of this reaction are arachidonic acid and ethanolamine. In the method described herein, FAAH activity is measured through the use of a radioactive substrate by quantification of reaction products, that is, [(14)C]-ethanolamine from [(14)C-ethanolamine]-AEA.

  3. Active inference and learning.

    PubMed

    Friston, Karl; FitzGerald, Thomas; Rigoli, Francesco; Schwartenbeck, Philipp; O'Doherty, John; Pezzulo, Giovanni

    2016-09-01

    This paper offers an active inference account of choice behaviour and learning. It focuses on the distinction between goal-directed and habitual behaviour and how they contextualise each other. We show that habits emerge naturally (and autodidactically) from sequential policy optimisation when agents are equipped with state-action policies. In active inference, behaviour has explorative (epistemic) and exploitative (pragmatic) aspects that are sensitive to ambiguity and risk respectively, where epistemic (ambiguity-resolving) behaviour enables pragmatic (reward-seeking) behaviour and the subsequent emergence of habits. Although goal-directed and habitual policies are usually associated with model-based and model-free schemes, we find the more important distinction is between belief-free and belief-based schemes. The underlying (variational) belief updating provides a comprehensive (if metaphorical) process theory for several phenomena, including the transfer of dopamine responses, reversal learning, habit formation and devaluation. Finally, we show that active inference reduces to a classical (Bellman) scheme, in the absence of ambiguity.

  4. Active Brownian rods

    NASA Astrophysics Data System (ADS)

    Peruani, Fernando

    2016-11-01

    Bacteria, chemically-driven rods, and motility assays are examples of active (i.e. self-propelled) Brownian rods (ABR). The physics of ABR, despite their ubiquity in experimental systems, remains still poorly understood. Here, we review the large-scale properties of collections of ABR moving in a dissipative medium. We address the problem by presenting three different models, of decreasing complexity, which we refer to as model I, II, and III, respectively. Comparing model I, II, and III, we disentangle the role of activity and interactions. In particular, we learn that in two dimensions by ignoring steric or volume exclusion effects, large-scale nematic order seems to be possible, while steric interactions prevent the formation of orientational order at large scales. The macroscopic behavior of ABR results from the interplay between active stresses and local alignment. ABR exhibit, depending on where we locate ourselves in parameter space, a zoology of macroscopic patterns that ranges from polar and nematic bands to dynamic aggregates.

  5. Active polarization descattering.

    PubMed

    Treibitz, Tali; Schechner, Yoav Y

    2009-03-01

    Vision in scattering media is important but challenging. Images suffer from poor visibility due to backscattering and attenuation. Most prior methods for scene recovery use active illumination scanners (structured and gated), which can be slow and cumbersome, while natural illumination is inapplicable to dark environments. The current paper addresses the need for a non-scanning recovery method, that uses active scene irradiance. We study the formation of images under widefield artificial illumination. Based on the formation model, the paper presents an approach for recovering the object signal. It also yields rough information about the 3D scene structure. The approach can work with compact, simple hardware, having active widefield, polychromatic polarized illumination. The camera is fitted with a polarization analyzer. Two frames of the scene are taken, with different states of the analyzer or polarizer. A recovery algorithm follows the acquisition. It allows both the backscatter and the object reflection to be partially polarized. It thus unifies and generalizes prior polarization-based methods, which had assumed exclusive polarization of either of these components. The approach is limited to an effective range, due to image noise and illumination falloff. Thus, the limits and noise sensitivity are analyzed. We demonstrate the approach in underwater field experiments.

  6. Active quantum plasmonics.

    PubMed

    Marinica, Dana Codruta; Zapata, Mario; Nordlander, Peter; Kazansky, Andrey K; M Echenique, Pedro; Aizpurua, Javier; Borisov, Andrei G

    2015-12-01

    The ability of localized surface plasmons to squeeze light and engineer nanoscale electromagnetic fields through electron-photon coupling at dimensions below the wavelength has turned plasmonics into a driving tool in a variety of technological applications, targeting novel and more efficient optoelectronic processes. In this context, the development of active control of plasmon excitations is a major fundamental and practical challenge. We propose a mechanism for fast and active control of the optical response of metallic nanostructures based on exploiting quantum effects in subnanometric plasmonic gaps. By applying an external dc bias across a narrow gap, a substantial change in the tunneling conductance across the junction can be induced at optical frequencies, which modifies the plasmonic resonances of the system in a reversible manner. We demonstrate the feasibility of the concept using time-dependent density functional theory calculations. Thus, along with two-dimensional structures, metal nanoparticle plasmonics can benefit from the reversibility, fast response time, and versatility of an active control strategy based on applied bias. The proposed electrical manipulation of light using quantum plasmonics establishes a new platform for many practical applications in optoelectronics.

  7. THE ACTIVE ASTEROIDS

    SciTech Connect

    Jewitt, David

    2012-03-15

    Some asteroids eject dust, unexpectedly producing transient, comet-like comae and tails. First ascribed to the sublimation of near-surface water ice, mass-losing asteroids (also called 'main-belt comets') can in fact be driven by a surprising diversity of mechanisms. In this paper, we consider 11 dynamical asteroids losing mass, in nine of which the ejected material is spatially resolved. We address mechanisms for producing mass loss including rotational instability, impact ejection, electrostatic repulsion, radiation pressure sweeping, dehydration stresses, and thermal fracture, in addition to the sublimation of ice. In two objects (133P and 238P) the repetitive nature of the observed activity leaves ice sublimation as the only reasonable explanation, while in a third ((596) Scheila), a recent impact is the cause. Another impact may account for activity in P/2010 A2, but this tiny object can also be explained as having shed mass after reaching rotational instability. Mass loss from (3200) Phaethon is probably due to cracking or dehydration at extreme ({approx}1000 K) perihelion temperatures, perhaps aided by radiation pressure sweeping. For the other bodies, the mass-loss mechanisms remain unidentified, pending the acquisition of more and better data. While the active asteroid sample size remains small, the evidence for an astonishing diversity of mass-loss processes in these bodies is clear.

  8. Active quantum plasmonics

    PubMed Central

    Marinica, Dana Codruta; Zapata, Mario; Nordlander, Peter; Kazansky, Andrey K.; M. Echenique, Pedro; Aizpurua, Javier; Borisov, Andrei G.

    2015-01-01

    The ability of localized surface plasmons to squeeze light and engineer nanoscale electromagnetic fields through electron-photon coupling at dimensions below the wavelength has turned plasmonics into a driving tool in a variety of technological applications, targeting novel and more efficient optoelectronic processes. In this context, the development of active control of plasmon excitations is a major fundamental and practical challenge. We propose a mechanism for fast and active control of the optical response of metallic nanostructures based on exploiting quantum effects in subnanometric plasmonic gaps. By applying an external dc bias across a narrow gap, a substantial change in the tunneling conductance across the junction can be induced at optical frequencies, which modifies the plasmonic resonances of the system in a reversible manner. We demonstrate the feasibility of the concept using time-dependent density functional theory calculations. Thus, along with two-dimensional structures, metal nanoparticle plasmonics can benefit from the reversibility, fast response time, and versatility of an active control strategy based on applied bias. The proposed electrical manipulation of light using quantum plasmonics establishes a new platform for many practical applications in optoelectronics. PMID:26824066

  9. Sesterterpenoids with Anticancer Activity

    PubMed Central

    Evidente, Antonio; Kornienko, Alexander; Lefranc, Florence; Cimmino, Alessio; Dasari, Ramesh; Evidente, Marco; Mathieu, Véronique; Kiss, Robert

    2016-01-01

    Terpenes have received a great deal of attention in the scientific literature due to complex, synthetically challenging structures and diverse biological activities associated with this class of natural products. Based on the number of C5 isoprene units they are generated from, terpenes are classified as hemi- (C5), mono- (C10), sesqui- (C15), di- (C20), sester- (C25), tri (C30), and tetraterpenes (C40). Among these, sesterterpenes and their derivatives known as sesterterpenoids, are ubiquitous secondary metabolites in fungi, marine organisms, and plants. Their structural diversity encompasses carbotricyclic ophiobolanes, polycyclic anthracenones, polycyclic furan-2-ones, polycyclic hydroquinones, among many other carbon skeletons. Furthermore, many of them possess promising biological activities including cytotoxicity and the associated potential as anticancer agents. This review discusses the natural sources that produce sesterterpenoids, provides sesterterpenoid names and their chemical structures, biological properties with the focus on anticancer activities and literature references associated with these metabolites. A critical summary of the potential of various sesterterpenoids as anticancer agents concludes the review. PMID:26295461

  10. Transport to Rhebpress activity.

    PubMed

    Garrido, Amanda; Brandt, Marta; Djouder, Nabil

    2016-01-01

    The small GTPases from the rat sarcoma (Ras) superfamily are a heterogeneous group of proteins of about 21 kDa that act as molecular switches, modulating cell signaling pathways and controlling diverse cellular processes. They are active when bound to guanosine triphosphate (GTP) and inactive when bound to guanosine diphosphate (GDP). Ras homolog enriched in brain (Rheb) is a member of the Ras GTPase superfamily and a key activator of the mammalian/mechanistic target of rapamycin complex 1 (mTORC1). We recently determined that microspherule protein 1 (MCRS1) maintains Rheb at lysosomal surfaces in an amino acid-dependent manner. MCRS1 depletion promotes the formation of the GDP-bound form of Rheb, which is then delocalized from the lysosomal platform and transported to endocytic recycling vesicles, leading to mTORC1 inactivation. During this delocalization process, Rheb-GDP remains farnesylated and associated with cellular endomembranes. These findings provide new insights into the regulation of small GTPases, whose activity depends on both their GTP/GDP switch state and their capacity to move between different cellular membrane-bound compartments. Dynamic spatial transport between compartments makes it possible to alter the proximity of small GTPases to their activatory sites depending on the prevailing physiological and cellular conditions.

  11. Thermal activity on Enceladus

    NASA Astrophysics Data System (ADS)

    Tobie, G.; Besserer, J.; Behounkova, M.; Cadek, O.; Choblet, G.; Sotin, C.

    2009-04-01

    Observations by Cassini have revealed that Enceladus' souh pole is highly active, with jets of icy particles and water vapour emanated from narrow tectonic ridges, called "tiger stripes". This jet activity is associated to a very high thermal emission mainly focused along the tectonic ridges. Heat power required to sustain such an activity is probably related to the dissipation of mechanical energy due to tidal forces exerted by Saturn. However, the dissipation process and its relation to the tectonic features are not clearly established. Both shear heating along the tectonic ridges and viscous dissipation in the convective part of the ice shell could contribute to the energy budget (Nimmo et al. 2007, Tobie et al. 2008). Tobie et al. (2008) pointed out that only interior models with a liquid water layer at depth, covering at least ~2/3 of the southern hemisphere, can explain the observed magnitude of dissipation and its particular location at the south pole. However, the long term stability of such a liquid reservoir remains problematic (Roberts and Nimmo 2007) and the possible link between the liquid reservoir and the surface activities is unknown. Concentration of tidal stresses along the tiger ridges have also been invoked as a mechanism to trigger the eruptive processes (Hurtford et al. 2007, Smith-Konter et al. 2008). However, those models do not take into account a realistic rheological structure for the ice shell when computing the fluctuating stress field. Moreover, the effect of the faults on the background tidal stress is neglected. In particular, low viscosity values are expected to be associated with the shear zone along the tiger stripes and may have a significant impact of the global tidal stress field. In order to self-consistently determine the tidal deformation and its impact on the thermal activity on Enceladus, we are currently developing a 3D model that combines a thermal convection code in spherical geometry (Choblet et al. 2007) and a

  12. Gender Issues: An Activity File.

    ERIC Educational Resources Information Center

    Fountain, Susan

    This activity file grew out of research of an "Images of Women in Development" project of the Centre for Global Education at the University of York, England. The activities are intended for students in the 8- to 13-year-old range to learn more about gender issues. The activities are divided into four sections: (1) awareness-raising activities in…

  13. Metric Activities, Grades K-6.

    ERIC Educational Resources Information Center

    Draper, Bob, Comp.

    This pamphlet presents worksheets for use in fifteen activities or groups of activities designed for teaching the metric system to children in grades K through 6. The approach taken in several of the activities is one of conversion between metric and English units. The majority of the activities concern length, area, volume, and capacity. A…

  14. Changing Conceptions of Activation Energy.

    ERIC Educational Resources Information Center

    Pacey, Philip D.

    1981-01-01

    Provides background material which relates to the concept of activation energy, fundamental in the study of chemical kinetics. Compares the related concepts of the Arrhenius activation energy, the activation energy at absolute zero, the enthalpy of activation, and the threshold energy. (CS)

  15. Science Activities in Energy: Conservation.

    ERIC Educational Resources Information Center

    Oak Ridge Associated Universities, TN.

    Presented is a science activities in energy package which includes 14 activities relating to energy conservation. Activities are simple, concrete experiments for fourth, fifth and sixth grades, which illustrate principles and problems relating to energy. Each activity is outlined on a simple card which is introduced by a question. A teacher's…

  16. Epsiodic Activity in Radio Galaxies

    SciTech Connect

    Saikia, D.J.; Konar, C.; Jamrozy, M.; Machalski, J.; Gupta, Neeraj; Stawarz, L.; Mack, K.-H.; Siemiginowska, A.; /Harvard-Smithsonian Ctr. Astrophys.

    2007-10-15

    One of the interesting issues in our understanding of active galactic nuclei is the duration of their active phase and whether such activity is episodic. In this paper we summarize our recent results on episodic activity in radio galaxies obtained with the GMRT and the VLA.

  17. [Tilt test and orthostatic intolerance: abnormalities in the neural sympathetic response to gravitational stimulus].

    PubMed

    Furlan, R

    2001-05-01

    In the present manuscript the different methodologies aimed at assessing the autonomic profile in humans during a gravitational stimulus have been described. In addition, strengths and drawbacks of the tilt test in relation to occasional orthostatic intolerance were addressed. Finally, different autonomic abnormalities underlying occasional and chronic orthostatic intolerance syndromes have been schematically highlighted. The direct recording of the neural sympathetic discharge from the peroneal nerve (MSNA), in spite of its invasive nature, still represents the recognized reference to quantify the changes in the sympathetic activity to the vessels attending postural modifications. The increase of plasma norepinephrine during a tilt test is achieved by both an increase in plasma spillover and a concomitant decrease in systemic clearance. Changes in the indices of cardiac sympathetic and vagal modulation may also be quantified during a tilt test by power spectrum analysis of RR interval variability. The spectral markers of cardiac autonomic control, if evaluated concomitantly with MSNA, may contribute to assess abnormalities in the regional distribution of the sympathetic activity to the heart and the vessels. The capability of the tilt test of reproducing a vasovagal event or of inducing "false positive responses" seems to be markedly affected by the age, thus suggesting that additional or different etiopathogenetic mechanisms might be involved in the loss of consciousness in older as compared to younger subjects. In subjects suffering from occasional or habitual neurally mediated syncope an increase or, respectively, a decrease in cardiac and vascular sympathetic modulation has been documented before the loss of consciousness. In patients with pure autonomic failure, a global dysautonomia affecting both the sympathetic and the vagal modulation to the heart, seems to be present. In chronic orthostatic intolerance, the most common form of dysautonomia of young women

  18. The active asteroids

    NASA Astrophysics Data System (ADS)

    Jewitt, D.

    2014-07-01

    Active asteroids simultaneously possess the orbits of main-belt asteroids and the physical appearances of comets; they show transient dust comae and solar-radiation pressure-swept tails. Apart from the shear surprise at finding such strange objects in the asteroid belt, the active asteroids are scientifically interesting for several reasons. Although we are limited to scarcely more than a dozen examples, the active asteroids already reveal the distinct action of different physical processes, each previously unobserved and carrying big-picture importance for understanding the solar system. 1. IMPACT. An unambiguous asteroid-asteroid impact was observed in 2010, when a 30-m scale body struck 100-km diameter (596) Scheila. Direct observations of impacts hold scientific importance both by sampling this natural process at full scale (compared with laboratory impacts conducted at tiny scales) and because impact statistics will allow us to assess the erosion rate in the asteroid belt and the contribution of asteroid dust to the interplanetary medium. 2. CRITICAL ROTATION. Several objects have been observed in which the best explanation seems to lie with spin-up to critical periods, presumably (but not certainly) caused by YORP. Examples of both likely mass-shedding (P/2010 A2, P/2013 P5) and full break-up (P/2013 R3, shown below) exist. It has been suggested that, at sub-kilometer sizes, spin-up disruption rates may surpass impact disruption rates. Future observations will show whether or not this is true, and may ultimately lead to an improved understanding of the physics of break-up. 3. THERMAL DISINTEGRATION. Geminid parent (3200) Phaethon shows on-going mass-loss at perihelion, driven by the 1000-K surface temperatures found there. The mechanisms appear to be some combination of thermal fracture and desiccation stress. 4. SUBLIMATION. Two objects have shown repeated activity that appears to be correlated with position in the orbit. The best example is 133P, which has

  19. Asthma and physical activity.

    PubMed

    Oseid, S

    1982-01-01

    Physical activity regularly leads to a decline in lung function in children and adolescents with asthma. This decline is a consequence of what is known as exercise-induced asthma (EIA), and can be determined and graded with the help of lung function tests before and after submaximal workloads on the ergometer cycle or the treadmill. Typical EIA appears in asthmatic individuals with entirely normal lung function before the effort, but EIA may also become clinically manifest with exercise in patients who have a subclinical degree of obstruction. The grade of EIA is essentially dependent on the duration and intensity of effort but also on the type of exercise. For example, free running causes much greater bronchoconstriction than swimming. The temperature and humidity of the inspired air may partially explain this difference. At the Voksentoppen Allergy Institute we find that about 85% of children develop a fall in lung function of 15% or more after a six minute ergometer cycle test. With typical EIA the fall may be totally or partially abolished by prophylactic medication 10 minutes before the start of the test. Disodium cromoglycate (Intal) and/or beta-adrenergic drugs are regularly used before all physical activity. Training programmes must be based on the interval principle. Swimming, ball games, relay races and dancing are examples of useful activities in the training and rehabilitation of children and adolescents with asthma. Through prophylactic medication and physical training, the aerobic work capacity, muscle strength and lung function in asthmatic children is improved. Training also leads to a significant mobilisation of mental resources and an increase in social integration.

  20. Active travel intervention and physical activity behaviour: an evaluation.

    PubMed

    Norwood, Patricia; Eberth, Barbara; Farrar, Shelley; Anable, Jillian; Ludbrook, Anne

    2014-07-01

    A physically active lifestyle is an important contributor to individual health and well-being. The evidence linking higher physical activity levels with better levels of morbidity and mortality is well understood. Despite this, physical inactivity remains a major global risk factor for mortality and, consequently, encouraging individuals to pursue physically active lifestyles has been an integral part of public health policy in many countries. Physical activity promotion and interventions are now firmly on national health policy agendas, including policies that promote active travel such as walking and cycling. This study evaluates one such active travel initiative, the Smarter Choices, Smarter Places programme in Scotland, intended to encourage uptake of walking, cycling and the use of public transport as more active forms of travel. House to house surveys were conducted before and after the programme intervention, in May/June 2009 and 2012 (12,411 surveys in 2009 and 9542 in 2012), for the evaluation of the programme. This paper analyses the physical activity data collected, focussing on what can be inferred from the initiative with regards to adult uptake of physical activity participation and whether, for those who participated in physical activity, the initiative impacted on meeting recommended physical activity guidelines. The results suggest that the initiative impacted positively on the likelihood of physical activity participation and meeting the recommended physical activity guidelines. Individuals in the intervention areas were on average 6% more likely to meet the physical activity guidelines compared to individuals in the non intervention areas. However, the absolute prevalence of physical activity participation declined in both intervention and control areas over time. Our evaluation of this active transport initiative indicates that similar programmes may aid in contributing to achieving physical activity targets and adds to the international

  1. Rationales for regulatory activity

    SciTech Connect

    Perhac, R.M.

    1997-02-01

    The author provides an outline which touches on the types of concerns about risk evaluation which are addressed in the process of establishing regulatory guides. Broadly he says regulatory activity serves three broad constituents: (1) Paternalism (private risk); (2) Promotion of social welfare (public risks); (3) Protection of individual rights (public risks). He then discusses some of the major issues encountered in reaching a decision on what is an acceptable level of risk within each of these areas, and how one establishes such a level.

  2. GPS Activities at SLAC

    SciTech Connect

    Behrend, Dirk

    2002-11-19

    The Alignment Engineering Group of the Stanford Linear Accelerator Center (SLAC) started to use RTK (real-time kinematic) GPS equipment in order to perform structure mapping and GIS-related tasks on the SLAC campus. In a first step a continuously observing GPS station (SLAC M40) was set up. This station serves as master control station for all differential GPS activities on site and its coordinates have been determined in the well-defined global geodetic datum ITRF2000 at a given reference epoch. Some trials have been performed to test the RTK method. The tests have proven RTK to be very fast and efficient.

  3. Reuse of activated alumina

    SciTech Connect

    Hobensack, J.E.

    1991-12-31

    Activated alumina is used as a trapping media to remove trace quantities of UF{sub 6} from process vent streams. The current uranium recovery method employs concentrated nitric acid which destroys the alumina pellets and forms a sludge which is a storage and disposal problem. A recently developed technique using a distilled water rinse followed by three dilute acid rinses removes on average 97% of the uranium, and leaves the pellets intact with crush strength and surface area values comparable with new material. Trapping tests confirm the effectiveness of the recycled alumina as UF{sub 6} trapping media.

  4. Crew Activity Analyzer

    NASA Technical Reports Server (NTRS)

    Murray, James; Kirillov, Alexander

    2008-01-01

    The crew activity analyzer (CAA) is a system of electronic hardware and software for automatically identifying patterns of group activity among crew members working together in an office, cockpit, workshop, laboratory, or other enclosed space. The CAA synchronously records multiple streams of data from digital video cameras, wireless microphones, and position sensors, then plays back and processes the data to identify activity patterns specified by human analysts. The processing greatly reduces the amount of time that the analysts must spend in examining large amounts of data, enabling the analysts to concentrate on subsets of data that represent activities of interest. The CAA has potential for use in a variety of governmental and commercial applications, including planning for crews for future long space flights, designing facilities wherein humans must work in proximity for long times, improving crew training and measuring crew performance in military settings, human-factors and safety assessment, development of team procedures, and behavioral and ethnographic research. The data-acquisition hardware of the CAA (see figure) includes two video cameras: an overhead one aimed upward at a paraboloidal mirror on the ceiling and one mounted on a wall aimed in a downward slant toward the crew area. As many as four wireless microphones can be worn by crew members. The audio signals received from the microphones are digitized, then compressed in preparation for storage. Approximate locations of as many as four crew members are measured by use of a Cricket indoor location system. [The Cricket indoor location system includes ultrasonic/radio beacon and listener units. A Cricket beacon (in this case, worn by a crew member) simultaneously transmits a pulse of ultrasound and a radio signal that contains identifying information. Each Cricket listener unit measures the difference between the times of reception of the ultrasound and radio signals from an identified beacon

  5. Minor meteor shower activity

    NASA Astrophysics Data System (ADS)

    Rendtel, J.

    2016-01-01

    Video meteor observations provide us with data to analyze structures in minor meteor showers or weak features in flux profiles. Samples obtained independently by other techniques allow to calibrate the data sets and to improve the confidence of results as demonstrated with a few results. Both, the confirmation of events predicted by model calculation and the input of observational data to improve the modelling results may help to better understand meteoroid stream evolution processes. Furthermore, calibrated data series can be used for studies of the long-term evolution of meteor shower activity.

  6. Enceladus: Starting Hydrothermal Activity

    NASA Technical Reports Server (NTRS)

    Matson, D. L.; Castillo-Rogez, J. C.; Johnson, T. V.; Lunine, J. I.; Davies, A. G.

    2011-01-01

    We describe a process for starting the hydrothermal activity in Enceladus' South Polar Region. The process takes advantage of fissures that reach the water table, about 1 kilometer below the surface. Filling these fissures with fresh ocean water initiates a flow of water up from an ocean that can be self-sustaining. In this hypothesis the heat to sustain the thermal anomalies and the plumes comes from a slightly warm ocean at depth. The heat is brought to the surface by water that circulates up, through the crust and then returns to the ocean.

  7. Active terahertz metamaterials

    SciTech Connect

    Chen, Hou-tong; O' Hara, John F; Taylor, Antoinette J

    2009-01-01

    In this paper we present an overview of research in our group in terahertz (THz) metamaterials and their applications. We have developed a series of planar metamaterials operating at THz frequencies, all of which exhibit a strong resonant response. By incorporating natural materials, e.g. semiconductors, as the substrates or as critical regions of metamaterial elements, we are able to effectively control the metamaterial resonance by the application of external stimuli, e.g., photoexcitation and electrical bias. Such actively controllable metamaterials provide novel functionalities for solid-state device applications with unprecedented performance, such as THz spectroscopy, imaging, and many others.

  8. Athena: Assessment Phase Activities

    NASA Astrophysics Data System (ADS)

    Lumb, David; Ayre, Mark

    2015-09-01

    The Athena mission concept has been proposed by the community in response to science themes of the Hot and Energetic Universe. Unlike other, competitive, mission selection exercises this "Large" class observatory mission has essentially been pre-selected. Nevertheless it has to be demonstrated that Athena meets the programmatic constraints of 1Bn euro cost cap, and a readiness level appropriate for formal mission adoption by the end 2019. This should be confirmed through a Phase A study conducted with two parallel industry activities. We describe the technical and programmatic content of these and latest progress in space and ground segment definition.

  9. Activation of solar flares

    SciTech Connect

    Cargill, P.J.; Migliuolo, S.; Hood, A.W.

    1984-11-01

    The physics of the activation of two-ribbon solar flares via the MHD instability of coronal arcades is presented. The destabilization of a preflare magnetic field is necessary for a rapid energy release, characteristic of the impulsive phase of the flare, to occur. The stability of a number of configurations are examined, and the physical consequences and relative importance of varying pressure profiles and different sets of boundary conditions (involving field-line tying) are discussed. Instability modes, driven unstable by pressure gradients, are candidates for instability. Shearless vs. sheared equilibria are also discussed. (ESA)

  10. ECLSS medical support activities

    NASA Technical Reports Server (NTRS)

    Crump, William J.; Kilgore, Melvin V., Jr.

    1991-01-01

    During the period from April 10, 1990 to April 9, 1991, the Consortium for the Space Life Sciences provided technical assistance to the NASA/MSFC water recovery efforts. This assistance was in the form of literature reviews, technical recommendations, and presentations. This final report summarizes the activities completed during this period and identifies those areas requiring additional efforts. The tasks which the University of Alabama in Huntsville (UAH) water recovery team addressed were either identified by MSFC technical representatives or chosen from those outlined in the subject statement of work.

  11. Bioethics activities in India.

    PubMed

    Kumar, Nandini K

    2006-01-01

    The Indian Council of Medical Research formulates, coordinates and promotes biomedical research in India. In 1980, they formulated the first national ethical guidelines. They offer a number of different training programmes, from 1 day to 6 months. The council is developing a core curriculum for teaching bioethics, which would be applied uniformly in medical schools throughout the country. Drug development and ethics is also important in India, particularly now that the local pharmaceutical industry is expanding and so many drugs trials are outsourced to the country. The council is also very active in encouraging the development of ethics review committees.

  12. AMS Prototyping Activities

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott

    2008-01-01

    This slide presentation reviews the activity around the Asynchronous Message Service (AMS) prototype. An AMS reference implementation has been available since late 2005. It is aimed at supporting message exchange both in on-board environments and over space links. The implementation incoroporates all mandatory elements of the draft recommendation from July 2007: (1) MAMS, AMS, and RAMS protocols. (2) Failover, heartbeats, resync. (3) "Hooks" for security, but no cipher suites included in the distribution. The performance is reviewed, and a Benchmark latency test over VxWorks Message Queues is shown as histograms of a count vs microseconds per 1000-byte message

  13. Imaging nervous system activity.

    PubMed

    Fields, R D; O'Donovan, M J

    2001-05-01

    Optical imaging methods rely upon visualization of three types of signals: (1) intrinsic optical signals, including light scattering and reflectance, birefringence, and spectroscopic changes of intrinsic molecules, such as NADH or oxyhemoglobin; (2) changes in fluorescence or absorbance of voltage-sensitive membrane dyes; and (3) changes in fluorescence or absorbance of calcium-sensitive indicator dyes. Of these, the most widely used approach is fluorescent microscopy of calcium-sensitive dyes. This unit describes protocols for the use of calcium-sensitive dyes and voltage-dependent dyes for studies of neuronal activity in culture, tissue slices, and en-bloc preparations of the central nervous system.

  14. ASTP RBCC Activities

    NASA Technical Reports Server (NTRS)

    Nelson, Karl W.; McArthur, Craig; Leopard, Larry (Technical Monitor)

    2000-01-01

    This presentation reviews the activities of the Advanced Space Transportation Program (ASTP) in the development of Rocket-Based Combined Cycle (RBCC)technology. The document consist of the presentation slides for a talk scheduled to be given to the World Aviation Congress and Exhibit of SAE. Included in the review is discussion of recent accomplishments in the area of Advanced Reusable technologies (ART), which includes work in flowpath testing, and system studies of the various vehicle/engine combinations including RBCC, Turbine Based Combined Cycle (TBCC) and Pulsed Detonation Engine (PDE). Pictures of the proposed RBCC Flowpaths are included. The next steps in the development process are reviewed.

  15. Hypnotic activity of brotizolam

    PubMed Central

    Uzzan, B.; Warot, D.; Chermat, P.; Dantlo, B.; Bornstein, S.; Simon, P.

    1983-01-01

    1 A double-blind, crossover study was carried out in general practice on the hypnotic activity of 0.25 mg brotizolam in patients aged between 18 and 70 years complaining of insomnia (11 men, 28 women). 2 Patients reported that they slept better, that they awoke less frequently and that they slept longer with brotizolam than with placebo. Overall the patients preferred brotizolam to placebo, and subjective assessments of well-being after brotizolam did not differ from those after placebo. Brotizolam was well tolerated and there were no incidents of note. PMID:6362701

  16. Monitoring international nuclear activity

    SciTech Connect

    Firestone, R.B.

    2006-05-19

    The LBNL Table of Isotopes website provides primary nuclearinformation to>150,000 different users annually. We have developedthe covert technology to identify users by IP address and country todetermine the kinds of nuclear information they are retrieving. Wepropose to develop pattern recognition software to provide an earlywarning system to identify Unusual nuclear activity by country or regionSpecific nuclear/radioactive material interests We have monitored nuclearinformation for over two years and provide this information to the FBIand LLNL. Intelligence is gleaned from the website log files. Thisproposal would expand our reporting capabilities.

  17. Neutron activation analysis system

    DOEpatents

    Taylor, M.C.; Rhodes, J.R.

    1973-12-25

    A neutron activation analysis system for monitoring a generally fluid media, such as slurries, solutions, and fluidized powders, including two separate conduit loops for circulating fluid samples within the range of radiation sources and detectors is described. Associated with the first loop is a neutron source that emits s high flux of slow and thermal neutrons. The second loop employs a fast neutron source, the flux from which is substantially free of thermal neutrons. Adjacent to both loops are gamma counters for spectrographic determination of the fluid constituents. Other gsmma sources and detectors are arranged across a portion of each loop for deterMining the fluid density. (Official Gazette)

  18. Physical Activity in Elderly

    PubMed Central

    Tirpakova, Veronika; Sedliak, Milan; Kern, Helmut; Mayr, Winfried; Hamar, Dušan

    2015-01-01

    Aging is a multifactorial irreversible process associated with significant decline in muscle mass and neuromuscular functions. One of the most efficient methods to counteract age-related changes in muscle mass and function is physical exercise. An alternative effective intervention to improve muscle structure and performance is electrical stimulation. In the present work we present the positive effects of physical activity in elderly and a study where the effects of a 8-week period of functional electrical stimulation and strength training with proprioceptive stimulation in elderly are compared. PMID:26913164

  19. Activities for the classroom

    NASA Astrophysics Data System (ADS)

    Stark, Joyce

    From my research experiences on board the R/V Atlantis, I have developed experiments that can be used in an integrated science program or for biology. These activities reflect life in extreme environments on Earth such as the hydrothermal vents and on other planets and moons in our solar system. Students can learn to map the oceans of Europa and discover how plants grow on Mars. Students have designed research projects from the experimentation that I was involved with through the REVEL program.

  20. The Active Solid Earth

    NASA Astrophysics Data System (ADS)

    Ebinger, Cynthia

    2016-04-01

    Dynamic processes in Earth's crust, mantle and core shape Earth's surface and magnetic field over time scales of seconds to millennia, and even longer time scales as recorded in the ca. 4 Ga rock record. Our focus is the earthquake-volcano deformation cycles that occur over human time scales, and their comparison with time-averaged deformation studies, with emphasis on mantle plume provinces where magma and volatile release and vertical tectonics are readily detectable. Active deformation processes at continental and oceanic rift and back arc zones provide critical constraints on mantle dynamics, the role of fluids (volatiles, magma, water), and plate rheology. For example, recent studies of the East African rift zone, which formed above one of Earth's largest mantle upwellings reveal that magma production and volatile release rates are comparable to those of magmatic arcs, the archetypal zones of continental crustal creation. Finite-length faults achieve some plate deformation, but magma intrusion in the form of dikes accommodates extension in continental, back-arc, and oceanic rifts, and intrusion as sills causes permanent uplift that modulates the local time-space scales of earthquakes and volcanoes. Volatile release from magma intrusion may reduce fault friction and permeability, facilitating aseismic slip and creating magma pathways. We explore the implications of active deformation studies to models of the time-averaged structure of plume and extensional provinces in continental and oceanic plate settings.

  1. Raman activated cell sorting.

    PubMed

    Song, Yizhi; Yin, Huabing; Huang, Wei E

    2016-08-01

    Single cell Raman spectra (SCRS) are intrinsic biochemical profiles and 'chemical images' of single cells which can be used to characterise phenotypic changes, physiological states and functions of cells. On the base of SCRS, Raman activated cell sorting (RACS) provides a label-free cell sorting approach, which can link single cells to their chemical or phenotypic profiles. Overcoming naturally weak Raman signals, establishing Raman biomarker as sorting criteria to RACS and improving specific sorting technology are three challenges of developing RACS. Advances on Raman spectroscopy such as stimulated Raman scattering (SRS) and pre-screening helped to increase RACS sorting speed. Entire SCRS can be characterised using pattern recognition methods, and specific Raman bands can be extracted as biomarkers for RACS. Recent advances on cell sorting technologies based on microfluidic device and surface-ejection enable accurate and reliable single cell sorting from complex samples. A high throughput RACS will be achievable in near future by integrating fast Raman detection system such as SRS with microfluidic RACS and Raman activated cell ejection (RACE).

  2. Microbiologically active nanocomposite media

    NASA Astrophysics Data System (ADS)

    Petranovskii, Vitalii; Panina, Lyudmila; Bogomolova, Eugenia; Belostotskaya, Galina

    2003-07-01

    The most recent approach to the development of novel antimicrobial and antifungal agents is based on the application of synthetic and natural zeolites, because zeolites are known to be the carrier and slow releaser of the heavy metals with olygodynamic properties. The microbiological activity of the ion-exchanged zeolites is attributed to the ionic state of the metal sreleased from the zeolites by ion re-exchange. In the present work we used low cost natural clinoptilolite (Cli) as a substrate for copper and silver in different states. The state of oxidation of the exchanged metal in zeolite with supported Cu and Ag species (in the form of cations, small clusters, sub-coloidal particles, large particles) in order to fit them to fulfill the following criteria: to demonstrate their high protective abilities against fungi and long-term stability. The study of structure of samples with XRD, UV-visible spectroscopy, FTIR, their stability with temperature and during storage was carried out for obtaining the correct correlation with microbiological activity.

  3. Activating event knowledge.

    PubMed

    Hare, Mary; Jones, Michael; Thomson, Caroline; Kelly, Sarah; McRae, Ken

    2009-05-01

    An increasing number of results in sentence and discourse processing demonstrate that comprehension relies on rich pragmatic knowledge about real-world events, and that incoming words incrementally activate such knowledge. If so, then even outside of any larger context, nouns should activate knowledge of the generalized events that they denote or typically play a role in. We used short stimulus onset asynchrony priming to demonstrate that (1) event nouns prime people (sale-shopper) and objects (trip-luggage) commonly found at those events; (2) location nouns prime people/animals (hospital-doctor) and objects (barn-hay) commonly found at those locations; and (3) instrument nouns prime things on which those instruments are commonly used (key-door), but not the types of people who tend to use them (hose-gardener). The priming effects are not due to normative word association. On our account, facilitation results from event knowledge relating primes and targets. This has much in common with computational models like LSA or BEAGLE in which one word primes another if they frequently occur in similar contexts. LSA predicts priming for all six experiments, whereas BEAGLE correctly predicted that priming should not occur for the instrument-people relation but should occur for the other five. We conclude that event-based relations are encoded in semantic memory and computed as part of word meaning, and have a strong influence on language comprehension.

  4. Active Near Earth Asteroids

    NASA Astrophysics Data System (ADS)

    Jenniskens, Peter

    2015-08-01

    Past activity from Near Earth Asteroids is recorded in the meteoroid streams that cause our meteor showers. Automated meteoroid orbit surveys by photographic, low-light video, specular radar, and head-echo radar reflections are providing the first maps of meteor shower activity at different particle sizes. There are distinct differences in particle size distributions among streams. The underlaying mechanisms that created these streams are illuminated: fragmentation from spin-up or thermal stresses, meteoroid ejection by water vapor drag, and ejection of icy particles by CO and CO2 sublimation. The distribution of the meteoroid orbital elements probe the subsequent evolution by planetary perturbations and sample the range of dynamical processes to which Near Earth Asteroids are exposed. The non-stream "sporadic" meteors probe early stages in the evolution from meteoroid streams into the zodiacal dust cloud. We see that the lifetime of large meteoroids is generally not limited by collisions. Results obtained by the CAMS video survey of meteoroid orbits are compared to those from other orbit surveys. Since October 2010, over 200,000 meteoroid orbits have been measured. First results from an expansion into the southern hemisphere are also presented, as are first results from the measurement of main element compositions. Among the many streams detected so far, the Geminid and Sextantid showers stand out by having a relatively high particle density and derive from parent bodies that appear to have originated in the main belt.

  5. Visualizing cellulase activity.

    PubMed

    Bubner, Patricia; Plank, Harald; Nidetzky, Bernd

    2013-06-01

    Commercial exploitation of lignocellulose for biotechnological production of fuels and commodity chemicals requires efficient-usually enzymatic-saccharification of the highly recalcitrant insoluble substrate. A key characteristic of cellulose conversion is that the actual hydrolysis of the polysaccharide chains is intrinsically entangled with physical disruption of substrate morphology and structure. This "substrate deconstruction" by cellulase activity is a slow, yet markedly dynamic process that occurs at different length scales from and above the nanometer range. Little is currently known about the role of progressive substrate deconstruction on hydrolysis efficiency. Application of advanced visualization techniques to the characterization of enzymatic degradation of different celluloses has provided important new insights, at the requisite nano-scale resolution and down to the level of single enzyme molecules, into cellulase activity on the cellulose surface. Using true in situ imaging, dynamic features of enzyme action and substrate deconstruction were portrayed at different morphological levels of the cellulose, thus providing new suggestions and interpretations of rate-determining factors. Here, we review the milestones achieved through visualization, the methods which significantly promoted the field, compare suitable (model) substrates, and identify limiting factors, challenges and future tasks.

  6. [Sport and physical activity].

    PubMed

    Bria, S; Zeppilli, P

    2010-01-01

    A regular sport activity involves physical and psychological benefits helping to improve the quality of life at any age. This aspect is even more important in the developing age, when the sport takes on a role of training and education. In this context, instances directed to allow adolescent and young adults with heart disease to practice sports seem justified, and they're becoming more pressing since when the diagnostic and therapeutic advances, especially in cardiac surgery and in interventional hemodynamics, allow an increasing number of patients, previously allocated to physical inactivity, to lead an active lifestyle. However, we have to keep in mind that congenital heart disease population is varied, not only by the nature of the malformation, but also because in the same cardiopathy you can find subjects in "natural history" or after surgery and, between them, subjects treated with several techniques and different outcomes. This justifies the need for a close collaboration between sports doctors, cardiologists and heart surgeons, particularly in the management of the most difficult and delicate problems.

  7. Active Astronomy Roadshow Haiti

    NASA Astrophysics Data System (ADS)

    Laycock, Silas; Oram, Kathleen; Alabre, Dayana; Douyon, Ralph; UMass Lowell Haiti Development Studies Center

    2016-01-01

    College-age Haitian students working with advisors and volunteers from UMass Lowell in 2015 developed and tested an activity-based K-8 curriculum in astronomy, space, and earth science. Our partner school is located in Les Cayes, Haiti a city where only 65% of children attend school, and only half of those will complete 6th grade. Astronomy provides an accessible and non-intimidating entry into science, and activity-based learning contrasts with the predominant traditional teaching techniques in use in Haiti, to reach and inspire a different cohort of learners. Teachers are predominantly women in Haiti, so part of the effort involves connecting them with scientists, engineers and teacher peers in the US. As a developing nation, it is vital for Haitian (as for all) children to grow up viewing women as leaders in science. Meanwhile in the US, few are aware of the reality of getting an education in a 3rd world nation (i.e. most of the world), so we also joined with teachers in Massachusetts to give US school children a peek at what daily life is like for their peers living in our vibrant but impoverished neighbor. Our Haitian partners are committed to helping their sister-schools with curriculum and educator workshops, so that the overall quality of education can rise, and not be limited to the very few schools with access to resources. We will describe the activites, motivation, and and the lessons learned from our first year of the project.

  8. Neutron activation for ITER

    SciTech Connect

    Barnes, C.W.; Loughlin, M.J.; Nishitani, Takeo

    1996-04-29

    There are three primary goals for the Neutron Activation system for ITER: maintain a robust relative measure of fusion power with stability and high dynamic range (7 orders of magnitude); allow an absolute calibration of fusion power (energy); and provide a flexible and reliable system for materials testing. The nature of the activation technique is such that stability and high dynamic range can be intrinsic properties of the system. It has also been the technique that demonstrated (on JET and TFTR) the highest accuracy neutron measurements in DT operation. Since the gamma-ray detectors are not located on the tokamak and are therefore amenable to accurate characterization, and if material foils are placed very close to the ITER plasma with minimum scattering or attenuation, high overall accuracy in the fusion energy production (7--10%) should be achievable on ITER. In the paper, a conceptual design is presented. A system is shown to be capable of meeting these three goals, also detailed design issues remain to be solved.

  9. Tracking dynamic team activity

    SciTech Connect

    Tambe, M.

    1996-12-31

    AI researchers are striving to build complex multi-agent worlds with intended applications ranging from the RoboCup robotic soccer tournaments, to interactive virtual theatre, to large-scale real-world battlefield simulations. Agent tracking - monitoring other agent`s actions and inferring their higher-level goals and intentions - is a central requirement in such worlds. While previous work has mostly focused on tracking individual agents, this paper goes beyond by focusing on agent teams. Team tracking poses the challenge of tracking a team`s joint goals and plans. Dynamic, real-time environments add to the challenge, as ambiguities have to be resolved in real-time. The central hypothesis underlying the present work is that an explicit team-oriented perspective enables effective team tracking. This hypothesis is instantiated using the model tracing technology employed in tracking individual agents. Thus, to track team activities, team models are put to service. Team models are a concrete application of the joint intentions framework and enable an agent to track team activities, regardless of the agent`s being a collaborative participant or a non-participant in the team. To facilitate real-time ambiguity resolution with team models: (i) aspects of tracking are cast as constraint satisfaction problems to exploit constraint propagation techniques; and (ii) a cost minimality criterion is applied to constrain tracking search. Empirical results from two separate tasks in real-world, dynamic environments one collaborative and one competitive - are provided.

  10. Regulation of inflammasome activation.

    PubMed

    Man, Si Ming; Kanneganti, Thirumala-Devi

    2015-05-01

    Inflammasome biology is one of the most exciting and rapidly growing areas in immunology. Over the past 10 years, inflammasomes have been recognized for their roles in the host defense against invading pathogens and in the development of cancer, auto-inflammatory, metabolic, and neurodegenerative diseases. Assembly of an inflammasome complex requires cytosolic sensing of pathogen-associated molecular patterns or danger-associated molecular patterns by a nucleotide-binding domain and leucine-rich repeat receptor (NLR) or absent in melanoma 2 (AIM2)-like receptors (ALR). NLRs and ALRs engage caspase-1, in most cases requiring the adapter protein apoptosis-associated speck-like protein containing a CARD (ASC), to catalyze proteolytic cleavage of pro-interleukin-1β (pro-IL-1β) and pro-IL-18 and drive pyroptosis. Recent studies indicate that caspase-8, caspase-11, IL-1R-associated kinases (IRAK), and receptor-interacting protein (RIP) kinases contribute to inflammasome functions. In addition, post-translational modifications, including ubiquitination, deubiquitination, phosphorylation, and degradation control almost every aspect of inflammasome activities. Genetic studies indicate that mutations in NLRP1, NLRP3, NLRC4, and AIM2 are linked with the development of auto-inflammatory diseases, enterocolitis, and cancer. Overall, these findings transform our understanding of the basic biology and clinical relevance of inflammasomes. In this review, we provide an overview of the latest development of inflammasome research and discuss how inflammasome activities govern health and disease.

  11. Activities in dementia care: A comparative assessment of activity types.

    PubMed

    Lokon, Elizabeth; Sauer, Philip E; Li, Yue

    2016-12-05

    This exploratory study compares the impact of five activity types on the well-being of institutionalized people with dementia: the intergenerational art program Opening Minds through Art, art and music therapies, creative activities, non-creative activities, and no activities at all. We validated the Scripps Modified Greater Cincinnati Chapter Well-Being Observational Tool, and used that instrument to systematically observe N = 67 people with dementia as they participated in different activity types. People with dementia showed the highest well-being scores during Opening Minds through Art compared to all other activities. No significant well-being differences were found between creative activities led by licensed art/music therapist versus regular activity staff. Furthermore, no significant well-being differences were found between creative and non-creative activities that were both led by regular activity staff. Overall, people with dementia benefit from participating in activities, regardless of the type (creative or non-creative), or who conducts them (licensed therapists or activity staff). However, in order for people with dementia to reach significantly high levels of overall well-being, we recommend that activities are specifically designed for people with dementia and incorporate a 1:1 ratio between people with dementia and well-trained volunteers/staff members.

  12. Effect of gender on vestibular sympathoexcitation

    NASA Technical Reports Server (NTRS)

    Ray, C. A.

    2000-01-01

    Studies have suggested that premenopausal women are more prone to orthostatic intolerance than men. Additionally, it has been postulated that the vestibulosympathetic reflex is important in regulating postural-related changes in sympathetic activity. The purpose of the present study was to determine whether men and women differ in their sympathetic and cardiovascular responses to stimulation of the otolith organs elicited by head-down rotation (HDR). Heart rate (HR), arterial pressure, calf blood flow (CBF), and leg muscle sympathetic nerve activity (MSNA) were measured during 3 min of HDR in the prone posture in 33 women and 30 men. With the exception of HR (71 +/- 2 and 63 +/- 1 beats/min for women and men, respectively; P < 0.01), all baseline variables were not different between genders. There were no gender differences in responses to HDR. MSNA increased 72 +/- 33 units (43%) in the men and 88 +/- 15 units (59%) in the women during HDR (P < 0.01). CBF decreased [-0.6 +/- 0.1 (15%) and -0.5 +/- 0.1 (19%) ml. min(-1). 100 ml(-1)] and calf vascular resistance increased [8 +/- 2 (21%) and 11 +/- 3 (25%) units during HDR for men and women, respectively (P < 0.01)]. Both in the men and women, HR increased 2 +/- 1 beats/min (P < 0.01). These results demonstrate that sympathetic activation during HDR in the prone posture is similar in men and women. Therefore, these findings suggest that the vestibulosympathetic reflex is not different between healthy men and women.

  13. The active video games' narrative impact on children's physical activities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Active video games (AVGs) capable of inducing physical activity offer an innovative approach to combating childhood obesity. Unfortunately, children's AVG game play decreases quickly, underscoring the need to identify novel methods for player engagement. Narratives have been demonstrated to influenc...

  14. Active Magnetic Regenerative Liquefier

    SciTech Connect

    Barclay, John A.; Oseen-Send, Kathryn; Ferguson, Luke; Pouresfandiary, Jamshid; Cousins, Anand; Ralph, Heather; Hampto, Tom

    2016-01-12

    This final report for the DOE Project entitled Active Magnetic Regenerative Liquefier (AMRL) funded under Grant DE-FG36-08GO18064 to Heracles Energy Corporation d.b.a. Prometheus Energy (Heracles/Prometheus) describes an active magnetic regenerative refrigerator (AMRR) prototype designed and built during the period from July 2008 through May 2011. The primary goal of this project was to make significant technical advances toward highly efficient liquefaction of hydrogen. Conventional hydrogen liquefiers at any scale have a maximum FOM of ~0.35 due primarily to the intrinsic difficulty of rapid, efficient compression of either hydrogen or helium working gases. Numerical simulation modeling of high performance AMRL designs indicates certain designs have promise to increase thermodynamic efficiency from a FOM of ~0.35 toward ~0.5 to ~0.6. The technical approach was the use of solid magnetic working refrigerants cycled in and out of high magnetic fields to build an efficient active regenerative magnetic refrigeration module providing cooling power for AMRL. A single-stage reciprocating AMRR with a design temperature span from ~290 K to ~120 K was built and tested with dual magnetic regenerators moving in and out of the conductively-cooled superconducting magnet subsystem. The heat transfer fluid (helium) was coupled to the process stream (refrigeration/liquefaction load) via high performance heat exchangers. In order to maximize AMRR efficiency a helium bypass loop with adjustable flow was incorporated in the design because the thermal mass of magnetic refrigerants is higher in low magnetic field than in high magnetic field. Heracles/Prometheus designed experiments to measure AMRR performance under a variety of different operational parameters such as cycle frequency, magnetic field strength, heat transfer fluid flow rate, amount of bypass flow of the heat transfer fluid while measuring work input, temperature span, cooling capability as a function of cold temperature

  15. Overview of Langley activities in active controls research

    NASA Technical Reports Server (NTRS)

    Abel, I.; Newsom, J. R.

    1981-01-01

    The application of active controls technology to reduce aeroelastic response of aircraft structures offers a potential for significant payoffs in terms of aerodynamic efficiency and weight savings. The activities of the Langley Research Center (laRC) in advancing active controls technology. Activities are categorized into the development of appropriate analysis tools, control law synthesis methodology, and experimental investigations aimed at verifying both analysis and synthesis methodology.

  16. Youth Physical Activity Resource Use and Activity Measured by Accelerometry

    ERIC Educational Resources Information Center

    Maslow, Andra L.; Colabianchi, Natalie

    2011-01-01

    Objectives: To examine whether use of physical activity resources (e.g., parks) was associated with daily physical activity measured by accelerometry. Methods: One hundred eleven adolescents completed a travel diary with concurrent accelerometry. The main exposure was self-reported use of a physical activity resource (none /1 resources). The main…

  17. Examining Activism in Practice: A Qualitative Study of Archival Activism

    ERIC Educational Resources Information Center

    Novak, Joy Rainbow

    2013-01-01

    While archival literature has increasingly discussed activism in the context of archives, there has been little examination of the extent to which archivists in the field have accepted or incorporated archival activism into practice. Scholarship that has explored the practical application of archival activism has predominately focused on case…

  18. Activity Based Curriculum for Elementary Education. Additional Activities, K-6.

    ERIC Educational Resources Information Center

    Wichita Public Schools, KS.

    This elementary curriculum is a vehicle to provide manipulative activities that reinforce academic skills through meaningful, relevant, activity-based awareness of modern society. The twenty-six activity plans included in the curriculum place a major emphasis upon realistic or concrete experiences that deal with the manipulation and exploration of…

  19. Active Play: Exploring the Influences on Children's School Playground Activities

    ERIC Educational Resources Information Center

    Hyndman, Brendon; Benson, Amanda; Telford, Amanda

    2016-01-01

    Because children spend so much of their time in schools, their playgrounds offer a good setting for promoting active play in young lives. Teachers, instead of considering active play a taxing demand on their busy day, have begun to develop an informal curriculum for it. The authors review the research on children's active play and explores its…

  20. 101 Environmental Education Activities. Booklet 2--Language Art Activities.

    ERIC Educational Resources Information Center

    Whitney, Helen, Comp.

    This booklet containing 20 language arts activities is the second in the series "101 Environmental Education Activities" produced by the Upper Mississippi River ECO-Center. The description of each activity contains learning objectives, directions, and suggested student evaluation standards. Elementary and intermediate level students…

  1. 101 Environmental Education Activities. Booklet 4--Science Activities.

    ERIC Educational Resources Information Center

    Whitney, Helen, Comp.

    Fourth in the series "101 Environmental Education Activities" by the Upper Mississippi River ECO-Center, the booklet contains 39 environment-based science activities directed to students in primary, intermediate, and junior high classes. Organization of the activities usually includes grade level, objectives, procedures, and materials,…

  2. 101 Environmental Education Activities. Booklet 1--Art and Music Activities.

    ERIC Educational Resources Information Center

    Whitney, Helen, Comp.

    First of a series of 6 publications containing environmental education activities, this booklet by the Upper Mississippi River ECO-Center describes 12 environmentally-based art and music activities for elementary and intermediate grades. Each activity description contains objectives, preparation, materials, directions, student evaluation, and…

  3. Is enhanced physical activity possible using active videogames?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our research indicated that 10– to 12-year-old children receiving two active Wii (TM)(Nintendo (R); Nintendo of America, Inc., Redmond, WA) console videogames were no more physically active than children receiving two inactive videogames. Research is needed on how active videogames may increase phys...

  4. Summary of JPL Activities

    NASA Technical Reports Server (NTRS)

    Timmerman, Paul J.; Surampudi, Subbarao

    2000-01-01

    A viewgraph presentation outlines the Jet Propulsion Laboratory (JPL) flight programs, including past, present and future missions targeting Solar System exploration. Details, including launch dates and batteries used, are given for Deep Space 1 (Asteroid Rendezvous), Deep Space 2 (Mars Penetrator), Mars Global Surveyor, Mars Surveyor '98, Stardust, Europa Orbiter, Mars Surveyor 2001, Mars 2003 Lander and Rover, and Genesis (Solar Dust Return). Earth science projects are also outlined: Active Cavity Radiometer Irradiance Monitor (ARIMSAT), Ocean Topography Experiment (TOPEX/Poseidon), Jason-1 (TOPEX follow-on), and QuikScat/Seawinds (Ocean Winds Tracking). The status, background, and plans are given for several batteries: (1) 2.5 inch common pressure vessel (CPV), (2) 3.5 inch CPV, (3) Ni-H2, and (4) Li-Ion.

  5. P21 activated kinases

    PubMed Central

    Rane, Chetan K; Minden, Audrey

    2014-01-01

    The p21 activated kinases (Paks) are well known effector proteins for the Rho GTPases Cdc42 and Rac. The Paks contain 6 members, which fall into 2 families of proteins. The first family consists of Paks 1, 2, and 3, and the second consists of Paks 4, 5, and 6. While some of the Paks are ubiquitously expressed, others have more restrictive tissue specificity. All of them are found in the nervous system. Studies using cell culture, transgenic mice, and knockout mice, have revealed important roles for the Paks in cytoskeletal organization and in many aspects of cell growth and development. This review discusses the basic structures of the Paks, and their roles in cell growth, development, and in cancer. PMID:24658305

  6. Extravehicular activity welding experiment

    NASA Technical Reports Server (NTRS)

    Watson, J. Kevin

    1989-01-01

    The In-Space Technology Experiments Program (INSTEP) provides an opportunity to explore the many critical questions which can only be answered by experimentation in space. The objective of the Extravehicular Activity Welding Experiment definition project was to define the requirements for a spaceflight experiment to evaluate the feasibility of performing manual welding tasks during EVA. Consideration was given to experiment design, work station design, welding hardware design, payload integration requirements, and human factors (including safety). The results of this effort are presented. Included are the specific objectives of the flight test, details of the tasks which will generate the required data, and a description of the equipment which will be needed to support the tasks. Work station requirements are addressed as are human factors, STS integration procedures and, most importantly, safety considerations. A preliminary estimate of the cost and the schedule for completion of the experiment through flight and postflight analysis are given.

  7. Active Piezoelectric Diaphragms

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G.; Effinger, Robert T., IV; Aranda, Isaiah, Jr.; Copeland, Ben M.; Covington, Ed W., III

    2002-01-01

    Several active piezoelectric diaphragms were fabricated by placing unelectroded piezoelectric disks between copper clad films patterned with Inter-Circulating Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is radially distributed electric field that mechanically strains the piezo-ceramic along the Z-axis (perpendicular to the applied electric field), rather than the expected in-plane (XY-axis) direction. Unlike other out of plane piezoelectric actuators, which are benders, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements while maintaining a constant circumference. This paper covers the fabrication and characterization of these diaphragms as a function of poling field strength, ceramic diameter and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage ranging from DC to 10 Hz.

  8. Mechanically Activated Ion Channels

    PubMed Central

    Ranade, Sanjeev S.; Syeda, Ruhma; Patapoutian, Ardem

    2015-01-01

    Mechanotransduction, the conversion of physical forces into biochemical signals, is an essential component of numerous physiological processes including not only conscious senses of touch and hearing, but also unconscious senses such as blood pressure regulation. Mechanically activated (MA) ion channels have been proposed as sensors of physical force, but the identity of these channels and an understanding of how mechanical force is transduced has remained elusive. A number of recent studies on previously known ion channels along with the identification of novel MA ion channels have greatly transformed our understanding of touch and hearing in both vertebrates and invertebrates. Here, we present an updated review of eukaryotic ion channel families that have been implicated in mechanotransduction processes and evaluate the qualifications of the candidate genes according to specified criteria. We then discuss the proposed gating models for MA ion channels and highlight recent structural studies of mechanosensitive potassium channels. PMID:26402601

  9. DPAL activities in Japan

    NASA Astrophysics Data System (ADS)

    Endo, Masamori; Wani, Fumio

    2015-02-01

    Activities on diode pumped alkali laser (DPAL) in Japan is reviewed. We have started alkali laser works in 2011, and currently, we are the only players in Japan. Our interests are application oriented, and it is not only defense but also industrial. DPAL is a good candidate as a source of remote laser machining, thanks to its scalability and extremely good beam quality. We are studying on scientific and engineering problems of Cs DPAL with a small-scale apparatus. A commercial diode laser with volume Bragg grating outcoupler is used to pump the gain cell longitudinally. A 6.5 W continuous-wave output with optical to optical efficiency of 56% (based on the absorbed power) has been achieved. Numerical simulation codes are developed to understand the physics of DPAL and to help future developments.

  10. Active submarine volcano sampled

    USGS Publications Warehouse

    Taylor, B.

    1983-01-01

    On June 4, 1982, two full dredge hauls of fresh lava were recovered from the upper flanks of Kavachi submarine volcano, Solomon Islands, in the western Pacific Ocean, from the water depths of 1,200 and 2,700 feet. the shallower dredge site was within 0.5 mile of the active submarine vent shown at the surface by an area of slick water, probably caused by gas emissions. Kavachi is a composite stratovolcano that has been observed to erupt every year or two for at least the last 30 years (see photographs). An island formed in 1952, 1961, 1965, and 1978; but, in each case, it rapidly eroded below sea level. The latest eruption was observed by Solair pilots during the several weeks up to and including May 18, 1982. 

  11. Mechanically Activated Ion Channels.

    PubMed

    Ranade, Sanjeev S; Syeda, Ruhma; Patapoutian, Ardem

    2015-09-23

    Mechanotransduction, the conversion of physical forces into biochemical signals, is essential for various physiological processes such as the conscious sensations of touch and hearing, and the unconscious sensation of blood flow. Mechanically activated (MA) ion channels have been proposed as sensors of physical force, but the identity of these channels and an understanding of how mechanical force is transduced has remained elusive. A number of recent studies on previously known ion channels along with the identification of novel MA ion channels have greatly transformed our understanding of touch and hearing in both vertebrates and invertebrates. Here, we present an updated review of eukaryotic ion channel families that have been implicated in mechanotransduction processes and evaluate the qualifications of the candidate genes according to specified criteria. We then discuss the proposed gating models for MA ion channels and highlight recent structural studies of mechanosensitive potassium channels.

  12. Monitoring active volcanoes

    USGS Publications Warehouse

    Tilling, Robert I.

    1987-01-01

    One of the most spectacular, awesomely beautiful, and at times destructive displays of natural energy is an erupting volcano, belching fume and ash thousands of meters into the atmosphere and pouring out red-hot molten lava in fountains and streams. Countless eruptions in the geologic past have produced volcanic rocks that form much of the Earth's present surface. The gradual disintegration and weathering of these rocks have yielded some of the richest farmlands in the world, and these fertile soils play a significant role in sustaining our large and growing population. Were it not for volcanic activity, the Hawaiian Islands with their sugar cane and pineapple fields and magnificent landscapes and seascapes would not exist to support their residents and to charm their visitors. Yet, the actual eruptive processes are catastrophic and can claim life and property.

  13. CNES gondola development activities

    NASA Astrophysics Data System (ADS)

    Vargas, André; Verdier, Nicolas; Escarnot, Jean-Pierre; Vargas, André

    Recent safety rules and gondola obsolescence oblige CNES to initiate new developments to improve performances according scientific needs. A large project called NOSYCA will able to offer versatile housekeeping and science telemetry system for Zero Pressure Balloons. This concept is modular, use IP protocol for scientific high data rate and mix telemetry systems to perform long duration flight. To respect safety duties, the long duration flight ISBA gondola is modified. New functions are implemented to increase reliability for stratospheric super and zero Pressure balloons flights. "Pointed gondola activity" is also concerned by improvements. After the First Fireball flight, new equipment designs are in progress for future missions. At least, boundary layer balloons performances of science payload and housekeeping system increase with new instrumentation and network telemetry concepts.

  14. Factors regulating microglia activation

    PubMed Central

    Kierdorf, Katrin; Prinz, Marco

    2013-01-01

    Microglia are resident macrophages of the central nervous system (CNS) that display high functional similarities to other tissue macrophages. However, it is especially important to create and maintain an intact tissue homeostasis to support the neuronal cells, which are very sensitive even to minor changes in their environment. The transition from the “resting” but surveying microglial phenotype to an activated stage is tightly regulated by several intrinsic (e.g., Runx-1, Irf8, and Pu.1) and extrinsic factors (e.g., CD200, CX3CR1, and TREM2). Under physiological conditions, minor changes of those factors are sufficient to cause fatal dysregulation of microglial cell homeostasis and result in severe CNS pathologies. In this review, we discuss recent achievements that gave new insights into mechanisms that ensure microglia quiescence. PMID:23630462

  15. Implementation team activities

    NASA Astrophysics Data System (ADS)

    Linder, F.

    2002-12-01

    The implementation Team (IT) is a body reporting to the SCSB,. It has been assigned the task of preparing and harmonising policy, standards and specification proposals for evaluation, qualification and quality control, thus enabling a coherent and cost-effective ESCC Specification System for the procurement of EEE space components. Among the 10 recommendations issued by the SCAHC, 7 have been studied under the auspices of the Implementation Team. Its main activities have been the updating and modernising of the ESA/SCC system in order to meet user needs and to be compatible with market trends. In particular it updated the technical aspects of generic specifications for the different component families and introduced the QML concept into the SCC system. It has also studied and discussed other topics such as procurement standards, a reliability system, mutual recognition, databases and the preferred parts list. A summary of the progress made in all these fields will be presented below.

  16. Actively stressed marginal networks.

    PubMed

    Sheinman, M; Broedersz, C P; MacKintosh, F C

    2012-12-07

    We study the effects of motor-generated stresses in disordered three-dimensional fiber networks using a combination of a mean-field theory, scaling analysis, and a computational model. We find that motor activity controls the elasticity in an anomalous fashion close to the point of marginal stability by coupling to critical network fluctuations. We also show that motor stresses can stabilize initially floppy networks, extending the range of critical behavior to a broad regime of network connectivities below the marginal point. Away from this regime, or at high stress, motors give rise to a linear increase in stiffness with stress. Finally, we demonstrate that our results are captured by a simple, constitutive scaling relation highlighting the important role of nonaffine strain fluctuations as a susceptibility to motor stress.

  17. Lightning activity on Jupiter

    NASA Technical Reports Server (NTRS)

    Borucki, W. J.; Bar-Nun, A.; Scarf, F. L.; Look, A. F.; Hunt, G. E.

    1982-01-01

    Photographic observations of the nightside of Jupiter by the Voyager 1 spacecraft show the presence of extensive lightning activity. Detection of whistlers by the plasma wave analyzer confirms the optical observations and implies that many flashes were not recorded by the Voyager camera because the intensity of the flashes was below the threshold sensitivity of the camera. Measurements of the optical energy radiated per flash indicate that the observed flashes had energies similar to that for terrestrial superbolts. The best estimate of the lightning energy dissipation rate of 0.0004 W/sq m was derived from a consideration of the optical and radiofrequency measurements. The ratio of the energy dissipated by lightning compared to the convective energy flux is estimated to be between 0.000027 and 0.00005. The terrestrial value is 0.0001.

  18. Small Active Radiation Monitor

    NASA Technical Reports Server (NTRS)

    Badhwar, Gautam D.

    2004-01-01

    A device, named small active radiation monitor, allows on-orbit evaluations during periods of increased radiation, after extravehicular activities, or at predesignated times for crews on such long-duration space missions as on the International Space Station. It also permits direct evaluation of biological doses, a task now performed using a combination of measurements and potentially inaccurate simulations. Indeed the new monitor can measure a full array of radiation levels, from soft x-rays to hard galactic cosmic-ray particles. With refinement, it will benefit commercial (nuclear power-plant workers, airline pilots, medical technicians, physicians/dentists, and others) and military personnel as well as the astronauts for whom thermoluminescent dosimeters are inadequate. Civilian and military personnel have long since graduated from film badges to thermoluminescent dosimeters. Once used, most dosimeters must be returned to a central facility for processing, a step that can take days or even weeks. While this suffices for radiation workers for whom exposure levels are typically very low and of brief duration, it does not work for astronauts. Even in emergencies and using express mail, the results can often be delayed by as much as 24 hours. Electronic dosimeters, which are the size of electronic oral thermometers, and tattlers, small electronic dosimeters that sound an alarm when the dose/dose rate exceeds preset values, are also used but suffer disadvantages similar to those of thermoluminescent dosimeters. None of these devices fully answers the need of rapid monitoring during the space missions. Instead, radiation is monitored by passive detectors, which are read out after the missions. Unfortunately, these detectors measure only the absorbed dose and not the biologically relevant dose equivalent. The new monitor provides a real-time readout, a time history of radiation exposures (both absorbed dose and biologically relevant dose equivalent), and a count of the

  19. Earthquake activity in Oklahoma

    SciTech Connect

    Luza, K.V.; Lawson, J.E. Jr. )

    1989-08-01

    Oklahoma is one of the most seismically active areas in the southern Mid-Continent. From 1897 to 1988, over 700 earthquakes are known to have occurred in Oklahoma. The earliest documented Oklahoma earthquake took place on December 2, 1897, near Jefferson, in Grant County. The largest known Oklahoma earthquake happened near El Reno on April 9, 1952. This magnitude 5.5 (mb) earthquake was felt from Austin, Texas, to Des Moines, Iowa, and covered a felt area of approximately 362,000 km{sup 2}. Prior to 1962, all earthquakes in Oklahoma (59) were either known from historical accounts or from seismograph stations outside the state. Over half of these events were located in Canadian County. In late 1961, the first seismographs were installed in Oklahoma. From 1962 through 1976, 70 additional earthquakes were added to the earthquake database. In 1977, a statewide network of seven semipermanent and three radio-telemetry seismograph stations were installed. The additional stations have improved earthquake detection and location in the state of Oklahoma. From 1977 to 1988, over 570 additional earthquakes were located in Oklahoma, mostly of magnitudes less than 2.5. Most of these events occurred on the eastern margin of the Anadarko basin along a zone 135 km long by 40 km wide that extends from Canadian County to the southern edge of Garvin County. Another general area of earthquake activity lies along and north of the Ouachita Mountains in the Arkoma basin. A few earthquakes have occurred in the shelves that border the Arkoma and Anadarko basins.

  20. Science Activities for School Trips.

    ERIC Educational Resources Information Center

    Quint, Walter C.

    1980-01-01

    Describes ways in which physics-learning activity packets can be used by high school students participating in trips organized by other departments. Provides an example of physics activities incorporated into an airplane trip to Disney World. (CS)

  1. Antinociceptive activity of Helicteres isora.

    PubMed

    Venkatesh, Sama; Laxmi, K Sai; Reddy, B Madhava; Ramesh, M

    2007-02-01

    Helicteres isora root extracts were studied for antinociceptive activity on acetic acid-induced writhing test in mice, at a dose of 250 mg/kg. Petroleum ether, chloroform and aqueous ethanol extracts have shown significant activity.

  2. Physical Activity and Your Heart

    MedlinePlus

    ... more energy than resting. Walking, running, dancing, swimming, yoga, and gardening are a few examples of physical activity. According to the Department of Health and Human Services' 2008 Physical Activity Guidelines for ...

  3. Environmental Education Tips: Weather Activities.

    ERIC Educational Resources Information Center

    Brainard, Audrey H.

    1989-01-01

    Provides weather activities including questions, on weather, heating the earth's surface, air, tools of the meteorologist, clouds, humidity, wind, and evaporation. Shows an example of a weather chart activity. (RT)

  4. Physical activity extends life expectancy

    Cancer.gov

    Leisure-time physical activity is associated with longer life expectancy, even at relatively low levels of activity and regardless of body weight, according to a study by a team of researchers led by the NCI.

  5. Antiviral activities of photoactive perylenequinones.

    PubMed

    Hudson, J B; Imperial, V; Haugland, R P; Diwu, Z

    1997-02-01

    Nine perylenequinones (PQ), including some familiar naturally occurring pigments, were compared for their light-mediated antiviral efficacies. Calphostin C was the most active compound against the two target viruses, herpes simplex virus type 1 and Sindbis virus. Hypocrellins A and B were also very active. However, three cercosporin-like PQ were substantially less active in spite of their high quantum yields of singlet oxygen, whereas phleichrome, another efficient singlet oxygen producer, showed no detectable antiviral activity. One other PQ, which was a very weak singlet oxygen producer, also showed no antiviral activity. None of the active compounds showed significant antiviral activity in the dark. Thus, for some groups of PQ there was correlation between quantum yield of singlet oxygen (1O2) and antiviral efficacy, but there are evidently other structural features of PQ that influence activity.

  6. Papermaking as a Science Activity.

    ERIC Educational Resources Information Center

    Fetters, Marcia K.

    2000-01-01

    Describes a simple procedure for making paper and provides some suggestions for extending and modifying the activity. The activity is correlated to the National Science Standards and Benchmarks for Science Literacy. (SAH)

  7. Diabetes Diet, Eating, & Physical Activity

    MedlinePlus

    ... Disease, & Other Dental Problems Diabetes & Sexual & Urologic Problems Diabetes Diet, Eating, & Physical Activity Nutrition and physical activity ... What foods can I eat if I have diabetes? You may worry that having diabetes means going ...

  8. The Study of Animal Activity

    ERIC Educational Resources Information Center

    Westling, Bruce

    1971-01-01

    Describes how to measure the daily rhythm of activity (photoperiodism) of small mammals. Three methods for recording information are reviewed including instructions for making a recorder. Includes suggestions for activities and experiments. (PR)

  9. Organic active materials for batteries

    SciTech Connect

    Abouimrane, Ali; Weng, Wei; Amine, Khalil

    2016-08-16

    A rechargeable battery includes a compound having at least two active sites, R.sup.1 and R.sup.2; wherein the at least two active sites are interconnected by one or more conjugated moieties; each active site is coordinated to one or more metal ions M.sup.a+ or each active site is configured to coordinate to one or more metal ions; and "a" is 1, 2, or 3.

  10. Insight into hydroxides-activated coals: chemical or physical activation?

    SciTech Connect

    Alcaniz-Monge, J.; Illan-Gomez, M.J.

    2008-02-15

    The objective of this paper is to get an insight into the chemical activation mechanism using KOH and NaOH as activated agents. Three coals have been selected as carbon precursors. It was found that KOH and NaOH develop a similar narrow microporosity, independently of the coal rank, whereas only KOH generates supermicroporosity. Temperature-programmed desorption experiments, carried out with impregnated anthracite, show differences on the gas evolved during the activated carbon preparation using the two activating agents. Thus, whereas hydrogen profiles are quite similar for both activated agents, the CO and H{sub 2}O profiles are different. It is remarkable the high amount of H{sub 2}O evolved at the maximum treatment temperature for both activating agents. The results obtained to allow conclusion that the chemical activation is due to a combination of different process driving the development of material porosity.

  11. Assessing and Increasing Physical Activity

    ERIC Educational Resources Information Center

    Van Camp, Carole M.; Hayes, Lynda B.

    2012-01-01

    Increasing physical activity is a crucial component of any comprehensive approach to combat the growing obesity epidemic. This review summarizes recent behavioral research on the measurement of physical activity and interventions aimed at increasing physical activity and provides directions for future research.

  12. Encapsulation of new active ingredients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The organic construct consumed as food comes packaged in units that carry the active components, protects the entrapped active materials until delivered to targeted human organ. The packaging and delivery role is mimicked in the microencapsulation tools used to deliver active ingredients in process...

  13. Art Activities for the Handicapped.

    ERIC Educational Resources Information Center

    Laurie, Frank, Comp.

    Intended for professionals interested in incorporating arts activities into the educational programs for disabled students, Part One of the document contains arts activities contributed by clinician-presenters in the 1978 Illinois series of Very Special Arts Festivals; while Part Two contains activities contributed by clinician-presenters and…

  14. Hospitality Services. Student Activity Book.

    ERIC Educational Resources Information Center

    Texas Tech Univ., Lubbock. Home Economics Curriculum Center.

    This student activity book contains pencil-and-paper activities for use in a hospitality services course focusing on the food and lodging segments of the hospitality and tourism industry. The activities are organized into 29 chapters on the following topics: hospitality services industry; professional ethics; organization/management structures in…

  15. Activation Cascading in Sign Production

    ERIC Educational Resources Information Center

    Navarrete, Eduardo; Peressotti, Francesca; Lerose, Luigi; Miozzo, Michele

    2017-01-01

    In this study, we investigated how activation unfolds in sign production by examining whether signs that are not produced have their representations activated by semantics (cascading of activation). Deaf signers were tested with a picture-picture interference task. Participants were presented with pairs of overlapping pictures and named the green…

  16. Yohimbine in neurally mediated syncope. Pathophysiological implications.

    PubMed Central

    Mosqueda-Garcia, R; Fernandez-Violante, R; Tank, J; Snell, M; Cunningham, G; Furlan, R

    1998-01-01

    In this study, we evaluated if increased sympathetic stimulation is an essential requirement for the development of neurally mediated syncope (NMS) by manipulating overall sympathetic outflow in subjects susceptible to tilt-induced syncope. Eight previously characterized patients with recurrent NMS (five females and three males; 34+/-2 yr) were recruited from the Vanderbilt Syncope Unit and eight age-matched controls underwent initial administration of clonidine (CLO) or yohimbine (YHO). This was done, prospectively, to determine doses of these agents that would increase or decrease plasma norepinephrine levels by >/= 30%. On a different day, in all subjects we determined intraarterial blood pressure, EKG and muscle sympathetic nerve activity (MSNA) both supine and during upright tilt. After this, subjects randomly received either CLO or YHO, and 3 h later another tilt was performed. After 1 wk, a similar procedure with the other drug was performed. During the two basal tilts, all the control subjects completed the study, whereas all the NMS patients developed syncope. Reduction in sympathetic tone by CLO resulted in a decreased tolerance to tilt in three out of eight controls and in all the NMS patients. In contrast, YHO not only increased basal plasma NorEpi levels and MSNA, but also prevented syncope in seven out of eight patients. In a selected population of patients, increased sympathetic activity is not a prerequisite for the development of syncope. Yohimbine-induced enhancement of sympathetic tone in patients with NMS improves orthostatic tolerance and raises the possibility that this drug may be a useful agent in the treatment of NMS. PMID:9819368

  17. RELAXIN ACTIVATES PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR GAMMA

    PubMed Central

    Singh, Sudhir; Bennett, Robert G

    2009-01-01

    SUMMARY Relaxin is a polypeptide hormone that triggers multiple signaling pathways through its receptor RXFP1. Many of relaxin’s functions, including vascular and antifibrotic effects, are similar to those induced by activation of PPARγ. In this study, we tested the hypothesis that relaxin signaling through RXFP1 would activate PPARγ activity. In cells overexpressing RXFP1 (HEK-RXFP1), relaxin increased transcriptional activity through a PPAR response element (PPRE) in a concentration-dependent manner. In cells lacking RXFP1, relaxin had no effect. Relaxin increased both the baseline activity and the response to the PPARγ agonists rosiglitazone and 15d-PGJ2, but not to agonists of PPARα or PPARδ. In HEK-RXFP1 cells infected with adenovirus expressing PPARγ, relaxin increased transcriptional activity through PPRE, and this effect was blocked with an adenovirus expressing a dominant-negative PPARγ. Knockdown of PPARγ using siRNA resulted in a decrease in the response to both relaxin and rosiglitazone. Both relaxin and rosiglitazone increased expression of the PPARγ target genes CD36 and LXRα in HEK-RXFP1 and in THP-1 cells naturally expressing RXFP1. Relaxin did not increase PPARγ mRNA or protein levels. Treatment of cells with GW9662, an inhibitor of PPARγ ligand binding, effectively blocked rosiglitazone-induced PPARγ activation, but had no effect on relaxin activation of PPARγ. These results suggest that relaxin activates PPARγ activity, and increases the overall response in the presence PPARγ agonists. This activation is dependent on the presence of RXFP1. Furthermore, relaxin activates PPARγ via a ligand-independent mechanism. These studies represent the first report that relaxin can activate the transcriptional activity of PPARγ. PMID:19712722

  18. Oriented active shape models.

    PubMed

    Liu, Jiamin; Udupa, Jayaram K

    2009-04-01

    Active shape models (ASM) are widely employed for recognizing anatomic structures and for delineating them in medical images. In this paper, a novel strategy called oriented active shape models (OASM) is presented in an attempt to overcome the following five limitations of ASM: 1) lower delineation accuracy, 2) the requirement of a large number of landmarks, 3) sensitivity to search range, 4) sensitivity to initialization, and 5) inability to fully exploit the specific information present in the given image to be segmented. OASM effectively combines the rich statistical shape information embodied in ASM with the boundary orientedness property and the globally optimal delineation capability of the live wire methodology of boundary segmentation. The latter characteristics allow live wire to effectively separate an object boundary from other nonobject boundaries with similar properties especially when they come very close in the image domain. The approach leads to a two-level dynamic programming method, wherein the first level corresponds to boundary recognition and the second level corresponds to boundary delineation, and to an effective automatic initialization method. The method outputs a globally optimal boundary that agrees with the shape model if the recognition step is successful in bringing the model close to the boundary in the image. Extensive evaluation experiments have been conducted by utilizing 40 image (magnetic resonance and computed tomography) data sets in each of five different application areas for segmenting breast, liver, bones of the foot, and cervical vertebrae of the spine. Comparisons are made between OASM and ASM based on precision, accuracy, and efficiency of segmentation. Accuracy is assessed using both region-based false positive and false negative measures and boundary-based distance measures. The results indicate the following: 1) The accuracy of segmentation via OASM is considerably better than that of ASM; 2) The number of landmarks

  19. Distributed Active Archive Center

    NASA Technical Reports Server (NTRS)

    Bodden, Lee; Pease, Phil; Bedet, Jean-Jacques; Rosen, Wayne

    1993-01-01

    The Goddard Space Flight Center Version 0 Distributed Active Archive Center (GSFC V0 DAAC) is being developed to enhance and improve scientific research and productivity by consolidating access to remote sensor earth science data in the pre-EOS time frame. In cooperation with scientists from the science labs at GSFC, other NASA facilities, universities, and other government agencies, the DAAC will support data acquisition, validation, archive and distribution. The DAAC is being developed in response to EOSDIS Project Functional Requirements as well as from requirements originating from individual science projects such as SeaWiFS, Meteor3/TOMS2, AVHRR Pathfinder, TOVS Pathfinder, and UARS. The GSFC V0 DAAC has begun operational support for the AVHRR Pathfinder (as of April, 1993), TOVS Pathfinder (as of July, 1993) and the UARS (September, 1993) Projects, and is preparing to provide operational support for SeaWiFS (August, 1994) data. The GSFC V0 DAAC has also incorporated the existing data, services, and functionality of the DAAC/Climate, DAAC/Land, and the Coastal Zone Color Scanner (CZCS) Systems.

  20. Photoperiodism and Enzyme Activity

    PubMed Central

    Queiroz, Orlando; Morel, Claudine

    1974-01-01

    Metabolic readjustments after a change from long days to short days appear, in Kalanchoe blossfeldiana, to be achieved through the operation of two main mechanisms: variation in enzyme capacity, and circadian rhythmicity. After a lag time, capacity in phosphoenolpyruvate carboxylase and capacity in aspartate aminotransferase increase exponentially and appear to be allometrically linked during 50 to 60 short days; then a sudden fall takes place in the activity of the former. Malic enzyme and alanine aminotransferase behave differently. Thus, the operation of the two sections of the pathway (before and after the malate step) give rise to a continuously changing functional compartmentation in the pathway. Circadian rhythmicity, on the other hand, produces time compartmentation through phase shifts and variation in amplitude, independently for each enzyme. These characteristics suggest that the operation of a so-called biological clock would be involved. We propose the hypothesis that feedback regulation would be more accurate and efficient when applied to an already oscillating, clock-controlled enzyme system. PMID:16658749

  1. Optically active quantum dots

    NASA Astrophysics Data System (ADS)

    Gerard, Valerie; Govan, Joseph; Loudon, Alexander; Baranov, Alexander V.; Fedorov, Anatoly V.; Gun'ko, Yurii K.

    2015-10-01

    The main goal of our research is to develop new types of technologically important optically active quantum dot (QD) based materials, study their properties and explore their biological applications. For the first time chiral II-VI QDs have been prepared by us using microwave induced heating with the racemic (Rac), D- and L-enantiomeric forms of penicillamine as stabilisers. Circular dichroism (CD) studies of these QDs have shown that D- and L-penicillamine stabilised particles produced mirror image CD spectra, while the particles prepared with a Rac mixture showed only a weak signal. It was also demonstrated that these QDs show very broad emission bands between 400 and 700 nm due to defects or trap states on the surfaces of the nanocrystals. These QDs have demonstrated highly specific chiral recognition of various biological species including aminoacids. The utilisation of chiral stabilisers also allowed the preparation of new water soluble white emitting CdS nano-tetrapods, which demonstrated circular dichroism in the band-edge region of the spectrum. Biological testing of chiral CdS nanotetrapods displayed a chiral bias for an uptake of the D- penicillamine stabilised nano-tetrapods by cancer cells. It is expected that this research will open new horizons in the chemistry of chiral nanomaterials and their application in nanobiotechnology, medicine and optical chemo- and bio-sensing.

  2. VERA Geodetic Activities

    NASA Technical Reports Server (NTRS)

    Jike, Takaaki; Tamura, Yoshiaki; Shizugami, Makoto

    2013-01-01

    This report briefly describes the geodetic activities of VERA in the year 2012. The regular geodetic observations are carried out both in K- and S/X-bands. The frequency of regular observations is three times a month-twice for the VERA internal observations in K-band. The networks of the S/X sessions are JADE of GSI and IVS-T2. The raw data of the T2 and JADE sessions are electronically transferred to the Bonn, Haystack, and GSI correlators via Internet. Gravimetric observations are carried out at the VERA stations. An SG was installed at Mizusawa and placed in the vicinity of the VERA antenna in order to monitor vertical displacement at the end of 2008, and the observations continued throughout the year. Also at the VERA-Ishigakijima station, continuous operation of the SG started in 2012. The crustal movements generated by the 2011 earthquake off the Pacific coast of Tohoku continued during 2012, and displacement of the VERA-Mizusawa position by post-seismic creeping continued.

  3. Active control of convection

    NASA Astrophysics Data System (ADS)

    Singer, Jonathan; Bau, Haim H.

    1991-12-01

    It is demonstrated theoretically that active (feedback) control can be used to alter the characteristics of thermal convection in a toroidal, vertical loop heated from below and cooled from above. As the temperature difference between the heated and cooled sections of the loop increases, the flow in the uncontrolled loop changes from no motion to steady, time-independent motion to temporally oscillatory, chaotic motion. With the use of a feedback controller effecting small perturbations in the boundary conditions, one can maintain the no-motion state at significantly higher temperature differences than the critical one corresponding to the onset of convection in the uncontrolled system. Alternatively, one can maintain steady, time-independent flow under conditions in which the flow would otherwise be chaotic. That is, the controller can be used to suppress chaos. Likewise, it is possible to stabilize periodic nonstable orbits that exist in the chaotic regime of the uncontrolled system. Finally, the controller also can be used to induce chaos in otherwise laminar (fully predictable), nonchaotic flow.

  4. ADASY (Active Daylighting System)

    NASA Astrophysics Data System (ADS)

    Vázquez-Moliní, Daniel; González-Montes, Mario; Fernández-Balbuena, Antonio Á.; Bernabéu, Eusebio; García-Botella, Ángel; García-Rodríguez, Lucas; Pohl, Wilfried

    2009-08-01

    The main objective of ADASY (Active Daylighting System) work is to design a façade static daylighting system oriented to office applications, mainly. The goal of the project is to save energy by guiding daylight into a building for lighting purpose. With this approach we can reduce the electrical load for artificial lighting, completing it with sustainable energy. The collector of the system is integrated on a vertical façade and its distribution guide is always horizontal inside of the false ceiling. ADASY is designed with a specific patent pending caption system, a modular light-guide and light extractor luminaire system. Special care has been put on the final cost of the system and its building integration purpose. The current ADASY configuration is able to illuminate 40 m2 area with a 300lx-400lx level in the mid time work hours; furthermore it has a good enough spatial uniformity distribution and a controlled glare. The data presented in this study are the result of simulation models and have been confirmed by a physical scaled prototype. ADASY's main advantages over regular illumination systems are: -Low maintenance; it has not mobile pieces and therefore it lasts for a long time and require little attention once installed. - No energy consumption; solar light continue working even if there has been a power outage. - High quality of light: the colour rendering of light is very high - Psychological benefits: People working with daylight get less stress and more comfort, increasing productivity. - Health benefits

  5. Battery equalization active methods

    NASA Astrophysics Data System (ADS)

    Gallardo-Lozano, Javier; Romero-Cadaval, Enrique; Milanes-Montero, M. Isabel; Guerrero-Martinez, Miguel A.

    2014-01-01

    Many different battery technologies are available for the applications which need energy storage. New researches are being focused on Lithium-based batteries, since they are becoming the most viable option for portable energy storage applications. As most of the applications need series battery strings to meet voltage requirements, battery imbalance is an important matter to be taken into account, since it leads the individual battery voltages to drift apart over time, and premature cells degradation, safety hazards, and capacity reduction will occur. A large number of battery equalization methods can be found, which present different advantages/disadvantages and are suitable for different applications. The present paper presents a summary, comparison and evaluation of the different active battery equalization methods, providing a table that compares them, which is helpful to select the suitable equalization method depending on the application. By applying the same weight to the different parameters of comparison, switch capacitor and double-tiered switching capacitor have the highest ratio. Cell bypass methods are cheap and cell to cell ones are efficient. Cell to pack, pack to cell and cell to pack to cell methods present a higher cost, size, and control complexity, but relatively low voltage and current stress in high-power applications.

  6. Perspectives in active liquid crystals.

    PubMed

    Majumdar, Apala; Cristina, Marchetti M; Virga, Epifanio G

    2014-11-28

    Active soft matter is a young, growing field, with potential applications to a wide variety of systems. This Theme Issue explores this emerging new field by highlighting active liquid crystals. The collected contributions bridge theory to experiment, mathematical theories of passive and active nematics, spontaneous flows to defect dynamics, microscopic to continuum levels of description, spontaneous activity to biological activation. While the perspectives offered here only span a small part of this rapidly evolving field, we trust that they might provide the interested reader with a taste for this new class of non-equilibrium systems and their rich behaviour.

  7. Recurrent Activity in Radio Galaxies

    SciTech Connect

    Jamrozy, Marek; Konar, Chiranjib; Machalski, Jerzy; Mack, Karl-Heinz; Saikia, Dhruba; Siemiginowska, Aneta; Stawarz, Lukasz; /KIPAC, Menlo Park /Jagiellonian U.

    2007-10-15

    One of the outstanding issues concerning extragalactic radio sources is the total duration of their active phase and the possible existence of duty cycles of their nuclear activity. A duty cycle can be recognized if there is a mechanism which preserves the information of past activity for a sufficiently long time after a new activity has started up. If a new cycle starts before the radio lobes created during a former activity period have faded, we can recognize this by the observations of a young radio source embedded in an old relic structure.

  8. Activated sintering of zirconium dioxide

    NASA Astrophysics Data System (ADS)

    Panin, V. E.; Slosman, A. I.; Matrenin, S. V.

    1996-02-01

    A new phenomenon has been observed — the activated sintering of a zirconium ceramic in the hydrogen-nitrogen plasma of a glow discharge. It is shown that the activation energy is considerably lower than the activation energy for sintering in a vacuum furnace. This makes it possible to reduce sintering temperature, refine the grains, and improve the mechanical properties of the ceramic. It is proposed that the mechanism by which sintering is activated is connected with the activating effect of hydrogen during a structural transformation involving the formation of oxynitride phases.

  9. Global optogenetic activation of inhibitory interneurons during epileptiform activity.

    PubMed

    Ledri, Marco; Madsen, Marita Grønning; Nikitidou, Litsa; Kirik, Deniz; Kokaia, Merab

    2014-02-26

    Optogenetic techniques provide powerful tools for bidirectional control of neuronal activity and investigating alterations occurring in excitability disorders, such as epilepsy. In particular, the possibility to specifically activate by light-determined interneuron populations expressing channelrhodopsin-2 provides an unprecedented opportunity of exploring their contribution to physiological and pathological network activity. There are several subclasses of interneurons in cortical areas with different functional connectivity to the principal neurons (e.g., targeting their perisomatic or dendritic compartments). Therefore, one could optogenetically activate specific or a mixed population of interneurons and dissect their selective or concerted inhibitory action on principal cells. We chose to explore a conceptually novel strategy involving simultaneous activation of mixed populations of interneurons by optogenetics and study their impact on ongoing epileptiform activity in mouse acute hippocampal slices. Here we demonstrate that such approach results in a brief initial action potential discharge in CA3 pyramidal neurons, followed by prolonged suppression of ongoing epileptiform activity during light exposure. Such sequence of events was caused by massive light-induced release of GABA from ChR2-expressing interneurons. The inhibition of epileptiform activity was less pronounced if only parvalbumin- or somatostatin-expressing interneurons were activated by light. Our data suggest that global optogenetic activation of mixed interneuron populations is a more effective approach for development of novel therapeutic strategies for epilepsy, but the initial action potential generation in principal neurons needs to be taken in consideration.

  10. Trypsin activity is not involved in premature, intrapancreatic trypsinogen activation.

    PubMed

    Halangk, Walter; Krüger, Burkhard; Ruthenbürger, Manuel; Stürzebecher, Jörg; Albrecht, Elke; Lippert, Hans; Lerch, Markus M

    2002-02-01

    A premature and intracellular activation of digestive zymogens is thought to be responsible for the onset of pancreatitis. Because trypsin has a critical role in initiating the activation cascade of digestive enzymes in the gut, it has been assumed that trypsin also initiates intracellular zymogen activation in the pancreas. We have tested this hypothesis in isolated acini and lobules from rat pancreas. Intracellular trypsinogen activation was induced by supramaximal secretagogue stimulation and measured using either specific trypsin substrates or immunoreactivity of the trypsinogen activation peptide (TAP). To prevent a trypsin-induced trypsinogen activation, we used the cell-permeant, highly specific, and reversible inhibitor Nalpha-(2-naphthylsulfonyl)-3-amidinophenylalanine-carboxymethylpiperazide (S124), and to prevent cathepsin-induced trypsinogen activation, we used the cysteine protease inhibitor E-64d. Incubation of acini or lobules in the presence of S124 completely prevented the generation of trypsin activity in response to supramaximal caerulein but had no effect whatsoever on the generation of TAP. Conversely, when trypsin activity was recovered at the end of the experiment by either washout of S124 from acini or extensive dilution of lobule homogenates, it was up to 400% higher than after caerulein alone and corresponded, in molar terms, to the generation of TAP. Both trypsin activity and TAP release were inhibited in parallel by E-64d. We conclude that caerulein-induced trypsinogen activation in the pancreas is caused by an E-64d-inhibitable mechanism such as cathepsin-induced trypsinogen activation, and neither involves nor requires intracellular trypsin activity. Specific trypsin inhibition, on the other hand, prevents 80% of trypsin inactivation or autodegradation in the pancreas.

  11. Dynamic Patterns in Active Fluids

    NASA Astrophysics Data System (ADS)

    Jülicher, Frank

    2012-02-01

    Biological matter is inherently dynamic and exhibits active properties. A key example is the force generation by molecular motors in the cell cytoskeleton. Such active processes give rise to the generation of active mechanical stresses and spontaneous flows in gel-like cytoskeletal networks. Active material behaviors play a key role for the dynamics of cellular processes such as cell locomotion and cell division. We will discuss intracellular flow patterns that are created by active processes in the cell cortex. By combining theory with quantitative experiments we show that observed flow patterns result from profiles of active stress generation in the system. We will also consider the situation where active stress is regulated by a diffusing molecular species. In this case, spatial concentration patterns are generated by the interplay of stress regulation and self-generated flow fields.

  12. Active Kids Active Minds: A Physical Activity Intervention to Promote Learning?

    ERIC Educational Resources Information Center

    lisahunter; Abbott, Rebecca; Macdonald, Doune; Ziviani, Jennifer; Cuskelly, Monica

    2014-01-01

    This study assessed the feasibility and impact of introducing a programme of an additional 30 minutes per day of moderate physical activity within curriculum time on learning and readiness to learn in a large elementary school in south-east Queensland, Australia. The programme, Active Kids Active Minds (AKAM), involved Year 5 students (n = 107),…

  13. Strategy as active waiting.

    PubMed

    Sull, Donald N

    2005-09-01

    Successful executives who cut their teeth in stable industries or in developed countries often stumble when they face more volatile markets. They falter, in part, because they assume they can gaze deep into the future and develop a long-term strategy that will confer a sustainable competitive advantage. But visibility into the future of volatile markets is sharply limited because so many different variables are in play. Factors such as technological innovation, customers' evolving needs, government policy, and changes in the capital markets interact with one another to create unexpected outcomes. Over the past six years, Donald Sull, an associate professor at London Business School, has led a research project examining some of the world's most volatile markets, from national markets like China and Brazil to industries like enterprise software, telecommunications, and airlines. One of the most striking findings from this research is the importance of taking action during comparative lulls in the storm. Huge business opportunities are relatively rare; they come along only once or twice in a decade. And, for the most part, companies can't manufacture those opportunities; changes in the external environment converge to make them happen. What managers can do is prepare for these golden opportunities by managing smart during the comparative calm of business as usual. During these periods of active waiting, leaders must probe the future and remain alert to anomalies that signal potential threats or opportunities; exercise restraint to preserve their war chests; and maintain discipline to keep the troops battle ready. When a golden opportunity or"sudden death"threat emerges, managers must have the courage to declare the main effort and concentrate resources to seize the moment.

  14. Mechanically Active Electrospun Materials

    NASA Astrophysics Data System (ADS)

    Robertson, Jaimee M.

    Electrospinning, a technique used to fabricate small diameter polymer fibers, has been employed to develop unique, active materials falling under two categories: (1) shape memory elastomeric composites (SMECs) and (2) water responsive fiber mats. (1) Previous work has characterized in detail the properties and behavior of traditional SMECs with isotropic fibers embedded in an elastomer matrix. The current work has two goals: (i) characterize laminated anisotropic SMECs and (ii) develop a fabrication process that is scalable for commercial SMEC manufacturing. The former ((i)) requires electrospinning aligned polymer fibers. The aligned fibers are similarly embedded in an elastomer matrix and stacked at various fiber orientations. The resulting laminated composite has a unique response to tensile deformation: after stretching and releasing, the composite curls. This curling response was characterized based on fiber orientation. The latter goal ((ii)) required use of a dual-electrospinning process to simultaneously electrospin two polymers. This fabrication approach incorporated only industrially relevant processing techniques, enabling the possibility of commercial application of a shape memory rubber. Furthermore, the approach had the added benefit of increased control over composition and material properties. (2) The strong elongational forces experienced by polymer chains during the electrospinning process induce molecular alignment along the length of electrospun fibers. Such orientation is maintained in the fibers as the polymer vitrifies. Consequently, residual stress is stored in electrospun fiber mats and can be recovered by heating through the polymer's glass transition temperature. Alternatively, the glass transition temperature can be depressed by introducing a plasticizing agent. Poly(vinyl acetate) (PVAc) is plasticized by water, and its glass transition temperature is lowered below room temperature. Therefore, the residual stress can be relaxed at room

  15. AMPK activators: mechanisms of action and physiological activities

    PubMed Central

    Kim, Joungmok; Yang, Goowon; Kim, Yeji; Kim, Jin; Ha, Joohun

    2016-01-01

    AMP-activated protein kinase (AMPK) is a central regulator of energy homeostasis, which coordinates metabolic pathways and thus balances nutrient supply with energy demand. Because of the favorable physiological outcomes of AMPK activation on metabolism, AMPK has been considered to be an important therapeutic target for controlling human diseases including metabolic syndrome and cancer. Thus, activators of AMPK may have potential as novel therapeutics for these diseases. In this review, we provide a comprehensive summary of both indirect and direct AMPK activators and their modes of action in relation to the structure of AMPK. We discuss the functional differences among isoform-specific AMPK complexes and their significance regarding the development of novel AMPK activators and the potential for combining different AMPK activators in the treatment of human disease. PMID:27034026

  16. Fluidization and Active Thinning by Molecular Kinetics in Active Gels.

    PubMed

    Oriola, David; Alert, Ricard; Casademunt, Jaume

    2017-02-24

    We derive the constitutive equations of an active polar gel from a model for the dynamics of elastic molecules that link polar elements. Molecular binding kinetics induces the fluidization of the material, giving rise to Maxwell viscoelasticity and, provided that detailed balance is broken, to the generation of active stresses. We give explicit expressions for the transport coefficients of active gels in terms of molecular properties, including nonlinear contributions on the departure from equilibrium. In particular, when activity favors linker unbinding, we predict a decrease of viscosity with activity-active thinning-of kinetic origin, which could explain some experimental results on the cell cortex. By bridging the molecular and hydrodynamic scales, our results could help understand the interplay between molecular perturbations and the mechanics of cells and tissues.

  17. Being active when you have heart disease

    MedlinePlus

    Heart disease - activity; CAD - activity; Coronary artery disease - activity; Angina - activity ... Getting regular exercise when you have heart disease is important. Exercise can make your heart muscle stronger. It may also help you be more active without chest pain or ...

  18. Rest Rust ! Physical active for active and healthy ageing

    PubMed Central

    Vollenbroek-Hutten, M; Pais, S; Ponce, S; Dekker-van Weering, M; Jansen-Kosterink, S; Schena, F; Tabarini, N; Carotenuto, F; Iadicicco, V; Illario, M

    2015-01-01

    The aim of this paper is to give an insight on how physical activity can be defined, parameterized and measured in older adults and on different options to deal with citizen physical activity promotion at European level. Three relevant aspects are highlighted: When talking about physical activity, two different aspects are often unfairly mixed up: “physical activity” and “physical capacity”. Physical activity, is referred to as the level of physical activity someone is actually performing in daily life.Physical capacity is referred to as the maximum physical activity a person can perform.Both physical activity and physical capacity can be expressed in different dimensions such as time, frequency, or type of activity with the consequence that there are many tools and techniques available. In order to support people to choose an appropriate instrument in their everyday practice a list of 9 criteria that are considered important is defined.Older adults score differently across the various physical dimensions, so strategies to promote physical activity should consider individual differences, in order to adapt for these variations. PMID:27042429

  19. Activated coconut shell charcoal carbon using chemical-physical activation

    NASA Astrophysics Data System (ADS)

    Budi, Esmar; Umiatin, Nasbey, Hadi; Bintoro, Ridho Akbar; Wulandari, Futri; Erlina

    2016-02-01

    The use of activated carbon from natural material such as coconut shell charcoal as metal absorbance of the wastewater is a new trend. The activation of coconut shell charcoal carbon by using chemical-physical activation has been investigated. Coconut shell was pyrolized in kiln at temperature about 75 - 150 °C for about 6 hours in producing charcoal. The charcoal as the sample was shieved into milimeter sized granule particle and chemically activated by immersing in various concentration of HCl, H3PO4, KOH and NaOH solutions. The samples then was physically activated using horizontal furnace at 400°C for 1 hours in argon gas environment with flow rate of 200 kg/m3. The surface morphology and carbon content of activated carbon were characterized by using SEM/EDS. The result shows that the pores of activated carbon are openned wider as the chemical activator concentration is increased due to an excessive chemical attack. However, the pores tend to be closed as further increasing in chemical activator concentration due to carbon collapsing.

  20. Silicon active photonic devices

    NASA Astrophysics Data System (ADS)

    Dimitropoulos, Dimitrios

    Active photonic devices utilizing the optical nonlinearities of silicon have emerged in the last 5 years and the effort for commercial photonic devices in the material that has been the workhorse of electronics has been building up since. This dissertation presents the theory for some of these devices. We are concerned herein with CW lasers, amplifiers and wavelength converters that are based on the Raman effect. There have already been cursory experimental demonstrations of these devices and some of their limitations are already apparent. Most of the limitations observed are because of the appearance of effects that are competing with stimulated Raman scattering. Under the high optical powers that are necessary for the Raman effect (tens to hundrends of mW's) the process of optical two-photon (TPA) absorption occurs. The absorption of optical power that it causes itself is weak but in the process electrons and holes are generated which can further absorb light through the free-carrier absorption effect (FCA). The effective "lifetime" that these carriers have determines the magnitude of the FCA loss. We present a model for the carrier lifetime in Silicon-On-Insulator (SOI) waveguides and numerical simulations to understand how this critical parameter varies and how it can be controlled. A p-i-n junction built along SOI waveguides can help achieve lifetime of the order of 20--100 ps but the price one has to pay is on-chip electrical power consumption on the order of 100's of mWs. We model CW Raman lasers and we find that the carrier lifetime reduces the output power. If the carrier lifetime exceeds a certain "critical" value optical losses become overwhelming and lasing is impossible. As we show, in amplifiers, the nonlinear loss does not only result in diminished gain, but also in a higher noise figure. Finally the effect of Coherent anti-Stokes Raman scattering (CARS) is examined. The effect is important because with a pump frequency at 1434nm coherent power

  1. Rapid Active Sampling Package

    NASA Technical Reports Server (NTRS)

    Peters, Gregory

    2010-01-01

    A field-deployable, battery-powered Rapid Active Sampling Package (RASP), originally designed for sampling strong materials during lunar and planetary missions, shows strong utility for terrestrial geological use. The technology is proving to be simple and effective for sampling and processing materials of strength. Although this originally was intended for planetary and lunar applications, the RASP is very useful as a powered hand tool for geologists and the mining industry to quickly sample and process rocks in the field on Earth. The RASP allows geologists to surgically acquire samples of rock for later laboratory analysis. This tool, roughly the size of a wrench, allows the user to cut away swaths of weathering rinds, revealing pristine rock surfaces for observation and subsequent sampling with the same tool. RASPing deeper (.3.5 cm) exposes single rock strata in-situ. Where a geologist fs hammer can only expose unweathered layers of rock, the RASP can do the same, and then has the added ability to capture and process samples into powder with particle sizes less than 150 microns, making it easier for XRD/XRF (x-ray diffraction/x-ray fluorescence). The tool uses a rotating rasp bit (or two counter-rotating bits) that resides inside or above the catch container. The container has an open slot to allow the bit to extend outside the container and to allow cuttings to enter and be caught. When the slot and rasp bit are in contact with a substrate, the bit is plunged into it in a matter of seconds to reach pristine rock. A user in the field may sample a rock multiple times at multiple depths in minutes, instead of having to cut out huge, heavy rock samples for transport back to a lab for analysis. Because of the speed and accuracy of the RASP, hundreds of samples can be taken in one day. RASP-acquired samples are small and easily carried. A user can characterize more area in less time than by using conventional methods. The field-deployable RASP used a Ni

  2. A new regional total electron content empirical model in northeast China

    NASA Astrophysics Data System (ADS)

    Feng, Jiandi; Wang, Zhengtao; Jiang, Weiping; Zhao, Zhenzhen; Zhang, Bingbing

    2016-10-01

    Using total electron content (TEC) data over one and a half solar cycles (1999-2015) provided by the Center for Orbit Determination in Europe (CODE), this paper proposes a new empirical TEC model for northeast China (40-50N, 120-130E). The model, called TECM-NEC, involves the multiplication of four separable components, including diurnal variation, seasonal variation, geomagnetic field dependency, and solar dependency. Diurnal variation is composed of three parts: the typical daily variation of TEC; corrections of Mid-latitude Summer Nighttime Anomaly (MSNA) that depend on geographic location, season, and local time; and corrections of day-to-night ratio under different seasons and solar activities. Four sub-harmonics of the year with annual, semiannual, four-, and three-month periods are used to describe seasonal variations. For geomagnetic variation, geomagnetic latitude is based on the latest International Geomagnetic Reference Field (IGRF12) model. Compared with similar empirical models, the solar proxy index F10.7P = (F10.7 + F10.7A)/2, where F10.7A is the 81-day running mean of daily F10.7, is chosen as having linear relationship with TEC for the model. This model has 43 coefficients, which are determined by nonlinear least squares fitting (NLSF) technique. The TECM-NEC model fits with the TEC/CODE input data with a bias of 0.03TECU and a RMS deviation of 2.76TECU. The proposed TECM-NEC model can reproduce the MSNA and nighttime TEC enhancements phenomenon over northeast China.

  3. Influences of hydration on post-exercise cardiovascular control in humans.

    PubMed

    Charkoudian, Nisha; Halliwill, John R; Morgan, Barbara J; Eisenach, John H; Joyner, Michael J

    2003-10-15

    Dehydration is known to decrease orthostatic tolerance and cause tachycardia, but little is known about the cardiovascular control mechanisms involved. To test the hypothesis that arterial baroreflex sensitivity increases during exercise-induced dehydration, we assessed arterial baroreflex responsiveness in 13 healthy subjects (protocol 1) at baseline (PRE-EX) and 1 h after (EX-DEH) 90 min of exercise to cause dehydration, and after subsequent intravenous rehydration with saline (EX-REH). Six of these subjects were studied a second time (protocol 2) with intravenous saline during exercise to prevent dehydration. We measured heart rate, central venous pressure and arterial pressure during all trials, and muscle sympathetic nerve activity (MSNA) during the post-exercise trials. Baroreflex responses were assessed using sequential boluses of nitroprusside and phenylephrine (modified Oxford technique). After exercise in protocol 1 (EX-DEH), resting blood pressure was decreased and resting heart rate was increased. Cardiac baroreflex gain, assessed as the responsiveness of heart rate or R-R interval to changes in systolic pressure, was diminished in the EX-DEH condition (9.17 +/- 1.06 ms mmHg-1 vs. PRE-EX: 18.68 +/- 2.22 ms mmHg-1, P < 0.05). Saline infusion after exercise did not alter the increase in HR post-exercise or the decrease in baroreflex gain (EX-REH: 10.20 +/- 1.43 ms mmHg-1; P > 0.10 vs. EX-DEH). Saline infusion during exercise (protocol 2) resulted in less of a post-exercise decrease in blood pressure and a smaller change in cardiac baroreflex sensitivity. Saline infusion caused a decrease in MSNA in protocol 1. We conclude that exercise-induced dehydration causes post-exercise changes in the baroreflex control of blood pressure that may contribute to, rather than offset, orthostatic intolerance.

  4. Enhanced NIF neutron activation diagnostics.

    PubMed

    Yeamans, C B; Bleuel, D L; Bernstein, L A

    2012-10-01

    The NIF neutron activation diagnostic suite relies on removable activation samples, leading to operational inefficiencies and a fundamental lower limit on the half-life of the activated product that can be observed. A neutron diagnostic system measuring activation of permanently installed samples could remove these limitations and significantly enhance overall neutron diagnostic capabilities. The physics and engineering aspects of two proposed systems are considered: one measuring the (89)Zr/(89 m)Zr isomer ratio in the existing Zr activation medium and the other using potassium zirconate as the activation medium. Both proposed systems could improve the signal-to-noise ratio of the current system by at least a factor of 5 and would allow independent measurement of fusion core velocity and fuel areal density.

  5. CDPK Activation in PRR Signaling.

    PubMed

    Seybold, Heike; Boudsocq, Marie; Romeis, Tina

    2017-01-01

    Calcium-dependent protein kinases undergo a rapid biochemical activation in response to an intracellular Ca increase induced by the PRR-dependent perception of a pathogen-related stimulus. Based on SDS gel resolution, the in-gel kinase assay allows the analysis of multiple in vivo protein samples in parallel, combining the advantage of protein separation according to molecular mass with the activity read-out of a protein kinase assay. It thus enables to follow the transient CDPK activation and inactivation in response to in vivo elicitation with a time-wise resolution. In addition, changes of CDPK phosphorylation activity often correlate with slight shifts in the enzyme's apparent molecular mass, indicating posttranslational modifications and a conformational change of the active enzyme compared to its inactive resting form. These band shifts can be detected by a simple immunoblotting to monitor CDPK activation.

  6. Swim pressure of active matter

    NASA Astrophysics Data System (ADS)

    Takatori, Sho; Yan, Wen; Brady, John; Caltech Team

    2014-11-01

    Through their self-motion, all active matter systems generate a unique ``swim pressure'' that is entirely athermal in origin. This new source for the active stress exists at all scales in both living and nonliving active systems, and also applies to larger organisms where inertia is important (i.e., the Stokes number is not small). Here we explain the origin of the swim stress and develop a simple thermodynamic model to study the self-assembly and phase separation in active soft matter. Our new swim stress perspective can help analyze and exploit a wide class of active soft matter, from swimming bacteria and catalytic nanobots, schools of fish and birds, and molecular motors that activate the cellular cytoskeleton.

  7. Enhanced NIF neutron activation diagnostics

    SciTech Connect

    Yeamans, C. B.; Bleuel, D. L.; Bernstein, L. A.

    2012-10-15

    The NIF neutron activation diagnostic suite relies on removable activation samples, leading to operational inefficiencies and a fundamental lower limit on the half-life of the activated product that can be observed. A neutron diagnostic system measuring activation of permanently installed samples could remove these limitations and significantly enhance overall neutron diagnostic capabilities. The physics and engineering aspects of two proposed systems are considered: one measuring the {sup 89}Zr/{sup 89m}Zr isomer ratio in the existing Zr activation medium and the other using potassium zirconate as the activation medium. Both proposed systems could improve the signal-to-noise ratio of the current system by at least a factor of 5 and would allow independent measurement of fusion core velocity and fuel areal density.

  8. Active Cells for Multifunctional Structures

    DTIC Science & Technology

    2014-09-24

    techniques to explore a variety of cell designs.  Designed a simplified active cell using Nitinol as the actuation method and relying on Joule heating...for contraction of the cell.  Developed manufacturing techniques for reliably creating Nitinol spring coils in a variety of diameters and gauges...design of the active cells to maximum the stroked length of the active cells by tuning the stiffness of a passive spring in parallel with the Nitinol

  9. Antiangiogenic Activity of Glycyrrhiza Extract

    NASA Astrophysics Data System (ADS)

    Li, Ying-Qiu

    The bioactivity of extract of glycyrrhiza was detected by zebrafish antiangiogenic model after 70% ethanol extract of glycyrrhiza was extracted with petroleum ether, ethyl acetate, n-butanol. The inhibition of the extracts in antiangiogenic activity showed that the highest active components existed in ethyl acetate extract of glycyrrhiza. The ethyl acetate extract of glycyrrhiza was separated by polyamide column chromatography to obtain 7 fractions (Fr1-Fr7), which Fr5 and Fr6 showed antiangiogenic activity.

  10. In Situ Activation of Microcapsules

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R. (Inventor); Mosier, Benjamin (Inventor)

    2000-01-01

    Disclosed are microcapsules comprising a polymer shell enclosing two or more immiscible liquid phases in which a drug, or a prodrug and a drug activator are partitioned into separate phases. or prevented from diffusing out of the microcapsule by a liquid phase in which the drug is poorly soluble. Also disclosed are methods of using the microcapsules for in situ activation of drugs where upon exposure to an appropriate energy source the internal phases mix and the drug is activated in situ.

  11. Macrophage Biochemistry, Activation and Function

    DTIC Science & Technology

    1981-01-01

    glucoeidase +8 . . Sulfatase c +8 Modified from Morahan, 1980. b(+)Exhibit@ activity; (-) lacks activity; (+) weak or marginal activity. ’References: (1...endoplasmic reticulum enzymes, sulfatase c and alkaline a-glucosidase. Dissociation of the lysosomal enzyme patterns from sulfatase c and alkaline r...1974; Beaufay et al., 1974). Peritoneal macrophages are deficient or contain inauf- • -𔃼 :’- 41 ficient quantities of the classical constituents to be

  12. L3 Study Team Activities

    NASA Astrophysics Data System (ADS)

    Shoemaker, David; L3ST Team

    2017-01-01

    The NASA-Chartered L3 Study Team is working to develop the US community participation and to support NASA's contribution to the ESA-led LISA mission to observe gravitational waves via space-based detectors. The present activities of the L3ST will be described, and the next steps for the Study Team will also be given. NASA supports travel activities and support for the Study Team activities.

  13. Active auditory mechanics in mosquitoes.

    PubMed Central

    Göpfert, M. C.; Robert, D.

    2001-01-01

    In humans and other vertebrates, hearing is improved by active contractile properties of hair cells. Comparable active auditory mechanics is now demonstrated in insects. In mosquitoes, Johnston's organ transduces sound-induced vibrations of the antennal flagellum. A non-muscular 'motor' activity enhances the sensitivity and tuning of the flagellar mechanical response in physiologically intact animals. This motor is capable of driving the flagellum autonomously, amplifying sound-induced vibrations at specific frequencies and intensities. Motor-related electrical activity of Johnston's organ strongly suggests that mosquito hearing is improved by mechanoreceptor motility. PMID:11270428

  14. Geomagnetic response to solar activity.

    NASA Technical Reports Server (NTRS)

    Mead, G. D.

    1972-01-01

    The relationship between solar activity and geomagnetic variations is discussed in the light of spacecraft data obtained during the last decade. The effects of centers of solar activity responsible for producing geomagnetic activity on earth are believed to be transmitted through the solar wind, and there is usually a delay of two or three days before the onset of magnetic activity. Attempts to make a one-to-one correspondence between specific solar events and specific magnetic storms, however, are usually unsuccessful, because of the complex and indirect processes linking the two phenomena. Normally, only statistical tendencies can be shown.

  15. Activated T lymphocytes in uveitis.

    PubMed Central

    Deschênes, J.; Char, D. H.; Kaleta, S.

    1988-01-01

    Two colour flow cytometry techniques were used to assess the activation stages of peripheral and intraocular T lymphocytes in uveitis. Increased numbers of T lymphocytes bearing the interleukin-2 (IL-2) receptors were found in intraocular fluids or peripheral blood or both of 35/51 patients with uveitis. This increased expression of IL-2 receptors on lymphocytes correlated with increased expression of other early T lymphocyte activation markers, HLA-DR and L-35. Both T helper cells (Leu-3A+) and suppressor cells (Leu 2A+) were activated in vivo. A positive correlation was seen between lymphocyte activation and clinical uveitis activity. In idiopathic uveitis activation of Leu-3A lymphocytes (helper/inducer) was significantly increased, and intraocular activation of the Leu-2A lymphocytes (cytotoxic/suppressor) was significantly decreased. These data show that some patients with idiopathic uveitis have a perturbation of T helper cells. Twenty-two of 31 patients with idiopathic uveitis, not associated with systemic disease, had increased peripheral T lymphocyte activation. This finding indicates that in some inflammations believed to be restricted to the eye an abnormal systemic immune activation exists. PMID:2964862

  16. Active surveillance for prostate cancer.

    PubMed

    Romero-Otero, Javier; García-Gómez, Borja; Duarte-Ojeda, José M; Rodríguez-Antolín, Alfredo; Vilaseca, Antoni; Carlsson, Sigrid V; Touijer, Karim A

    2016-03-01

    It is worth distinguishing between the two strategies of expectant management for prostate cancer. Watchful waiting entails administering non-curative androgen deprivation therapy to patients on development of symptomatic progression, whereas active surveillance entails delivering curative treatment on signs of disease progression. The objectives of the two management strategies and the patients enrolled in either are different: (i) to review the role of active surveillance as a management strategy for patients with low-risk prostate cancer; and (ii) review the benefits and pitfalls of active surveillance. We carried out a systematic review of active surveillance for prostate cancer in the literature using the National Center for Biotechnology Information's electronic database, PubMed. We carried out a search in English using the terms: active surveillance, prostate cancer, watchful waiting and conservative management. Selected studies were required to have a comprehensive description of the demographic and disease characteristics of the patients at the time of diagnosis, inclusion criteria for surveillance, and a protocol for the patients' follow up. Review articles were included, but not multiple papers from the same datasets. Active surveillance appears to reduce overtreatment in patients with low-risk prostate cancer without compromising cancer-specific survival at 10 years. Therefore, active surveillance is an option for select patients who want to avoid the side-effects inherent to the different types of immediate treatment. However, inclusion criteria for active surveillance and the most appropriate method of monitoring patients on active surveillance have not yet been standardized.

  17. International Activities Related to Pesticides

    EPA Pesticide Factsheets

    Regulating pesticides involves many international issues and working with our regulatory partners in other countries. Learn about EPA's activities, upcoming meetings and workshops, and various regulatory issues.

  18. Physical Activity and Cancer Survivorship

    PubMed Central

    Garcia, David O.; Thomson, Cynthia A.

    2015-01-01

    There has been an increase in the cancer survivor population in the United States over the past several decades primarily due to improvements in early detection of first malignancies and effective treatment modalities. A wealth of evidence has demonstrated that regular physical activity is associated with a lower risk of death, all-cause mortality, cancer recurrence, and several chronic diseases, including type 2 diabetes and cardiovascular disease, common comorbid conditions in people who have survived cancer. Physical activity also is a central component of weight management. Methods This review summarizes the current physical activity recommendations and the evidence linking physical activity to improvements in weight management, physiological effects, and psychological health outcomes for cancer survivors. Results The available literature suggests physical activity is safe and is positively associated with weight management, cardiorespiratory fitness, muscular strength and endurance, quality of life, fatigue, and other psychosocial factors in cancer survivors. Yet relationships related to specific cancer diagnoses, treatments, and underlying cardiometabolic mechanisms associated with survival have not been thoroughly examined in randomized controlled trials. Furthermore, factors that influence adherence to physical activity behaviors must be identified to develop effective exercise programs. The use of objective measures of physical activity and the standardization of reporting outcome measures within intervention trials are needed to complement this effort. Conclusions Healthcare providers should consider individual differences among cancer survivors and tailor physical activity programs to meet the individual needs of the patient to assist in the adoption and maintenance of a physically active lifestyle. PMID:25335787

  19. Studies in geophysics: Active tectonics

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Active tectonics is defined within the study as tectonic movements that are expected to occur within a future time span of concern to society. Such movements and their associated hazards include earthquakes, volcanic eruptions, and land subsidence and emergence. The entire range of geology, geophysics, and geodesy is, to some extent, pertinent to this topic. The needs for useful forecasts of tectonic activity, so that actions may be taken to mitigate hazards, call for special attention to ongoing tectonic activity. Further progress in understanding active tectonics depends on continued research. Particularly important is improvement in the accuracy of dating techniques for recent geologic materials.

  20. Demand Activated Manufacturing Architecture

    SciTech Connect

    Bender, T.R.; Zimmerman, J.J.

    2001-02-07

    Honeywell Federal Manufacturing & Technologies (FM&T) engineers John Zimmerman and Tom Bender directed separate projects within this CRADA. This Project Accomplishments Summary contains their reports independently. Zimmerman: In 1998 Honeywell FM&T partnered with the Demand Activated Manufacturing Architecture (DAMA) Cooperative Business Management Program to pilot the Supply Chain Integration Planning Prototype (SCIP). At the time, FM&T was developing an enterprise-wide supply chain management prototype called the Integrated Programmatic Scheduling System (IPSS) to improve the DOE's Nuclear Weapons Complex (NWC) supply chain. In the CRADA partnership, FM&T provided the IPSS technical and business infrastructure as a test bed for SCIP technology, and this would provide FM&T the opportunity to evaluate SCIP as the central schedule engine and decision support tool for IPSS. FM&T agreed to do the bulk of the work for piloting SCIP. In support of that aim, DAMA needed specific DOE Defense Programs opportunities to prove the value of its supply chain architecture and tools. In this partnership, FM&T teamed with Sandia National Labs (SNL), Division 6534, the other DAMA partner and developer of SCIP. FM&T tested SCIP in 1998 and 1999. Testing ended in 1999 when DAMA CRADA funding for FM&T ceased. Before entering the partnership, FM&T discovered that the DAMA SCIP technology had an array of applications in strategic, tactical, and operational planning and scheduling. At the time, FM&T planned to improve its supply chain performance by modernizing the NWC-wide planning and scheduling business processes and tools. The modernization took the form of a distributed client-server planning and scheduling system (IPSS) for planners and schedulers to use throughout the NWC on desktops through an off-the-shelf WEB browser. The planning and scheduling process within the NWC then, and today, is a labor-intensive paper-based method that plans and schedules more than 8,000 shipped parts

  1. Platelet activating factor activity in the phospholipids of bovine spermatozoa

    SciTech Connect

    Parks, J.E.; Hough, S.; Elrod, C. )

    1990-11-01

    Platelet activating factor (PAF) has been detected in sperm from several mammalian species and can affect sperm motility and fertilization. Because bovine sperm contain a high percentage of ether-linked phospholipid precursors required for PAF synthesis, a study was undertaken to determine the PAF activity of bovine sperm phospholipids. Total lipids of washed, ejaculated bull sperm were extracted, and phospholipids were fractionated by thin-layer chromatography. Individual phospholipid fractions were assayed for PAF activity on the basis of (3H)serotonin release from equine platelets. PAF activity was detected in the PAF fraction (1.84 pmol/mumol total phospholipid) and in serine/inositol (PS/PI), choline (CP), and ethanolamine phosphoglyceride (EP) and cardiolipin (CA) fractions. Activity was highest in the CP fraction (8.05 pmol/mumol total phospholipid). Incomplete resolution of PAF and neutral lipids may have contributed to the activity in the PS/PI and CA fractions, respectively. Phospholipids from nonsperm sources did not stimulate serotonin release. Platelet activation by purified PAF and by sperm phospholipid fractions was inhibited by the receptor antagonist SRI 63-675. These results indicate that bovine sperm contain PAF and that other sperm phospholipids, especially CP and EP, which are high in glycerylether components, are capable of receptor-mediated platelet activation.

  2. Brain activation associated with active and passive lower limb stepping

    PubMed Central

    Jaeger, Lukas; Marchal-Crespo, Laura; Wolf, Peter; Riener, Robert; Michels, Lars; Kollias, Spyros

    2014-01-01

    Reports about standardized and repeatable experimental procedures investigating supraspinal activation in patients with gait disorders are scarce in current neuro-imaging literature. Well-designed and executed tasks are important to gain insight into the effects of gait-rehabilitation on sensorimotor centers of the brain. The present study aims to demonstrate the feasibility of a novel imaging paradigm, combining the magnetic resonance (MR)-compatible stepping robot (MARCOS) with sparse sampling functional magnetic resonance imaging (fMRI) to measure task-related BOLD signal changes and to delineate the supraspinal contribution specific to active and passive stepping. Twenty-four healthy participants underwent fMRI during active and passive, periodic, bilateral, multi-joint, lower limb flexion and extension akin to human gait. Active and passive stepping engaged several cortical and subcortical areas of the sensorimotor network, with higher relative activation of those areas during active movement. Our results indicate that the combination of MARCOS and sparse sampling fMRI is feasible for the detection of lower limb motor related supraspinal activation. Activation of the anterior cingulate and medial frontal areas suggests motor response inhibition during passive movement in healthy participants. Our results are of relevance for understanding the neural mechanisms underlying gait in the healthy. PMID:25389396

  3. Active Brownian particles with velocity-alignment and active fluctuations

    NASA Astrophysics Data System (ADS)

    Großmann, R.; Schimansky-Geier, L.; Romanczuk, P.

    2012-07-01

    We consider a model of active Brownian particles (ABPs) with velocity alignment in two spatial dimensions with passive and active fluctuations. Here, active fluctuations refers to purely non-equilibrium stochastic forces correlated with the heading of an individual active particle. In the simplest case studied here, they are assumed to be independent stochastic forces parallel (speed noise) and perpendicular (angular noise) to the velocity of the particle. On the other hand, passive fluctuations are defined by a noise vector independent of the direction of motion of a particle, and may account, for example, for thermal fluctuations. We derive a macroscopic description of the ABP gas with velocity-alignment interaction. Here, we start from the individual-based description in terms of stochastic differential equations (Langevin equations) and derive equations of motion for the coarse-grained kinetic variables (density, velocity and temperature) via a moment expansion of the corresponding probability density function. We focus here on the different impact of active and passive fluctuations on onset of collective motion and show how active fluctuations in the active Brownian dynamics can change the phase-transition behaviour of the system. In particular, we show that active angular fluctuations lead to an earlier breakdown of collective motion and to the emergence of a new bistable regime in the mean-field case.

  4. From Physical Activity Guidelines to a National Activity Plan

    ERIC Educational Resources Information Center

    Bornstein, Daniel B.; Pate, Russell R.

    2014-01-01

    The U.S. National Physical Activity Plan (NPAP) is a comprehensive strategic plan aimed at increasing physical activity levels in all segments of the American population. The purpose of this paper is to summarize the development of the NPAP, provide an update on the status of the NPAP, and comment on the future of the NPAP. The NPAP was released…

  5. How Active Are Your Students? Increasing Physical Activity in Schools

    ERIC Educational Resources Information Center

    Avery, Marybell; Brandt, Janet

    2010-01-01

    The U. S. Department of Health and Human Services recommends that youth engage in at least 60 minutes of physical activity each day, most of which should be either moderate- or vigorous-intensity aerobic physical activity. Half of this amount (30 minutes) should be achieved during the school day. NASPE provides guidance in the form of a…

  6. Reading Aloud Activity in L2 and Cerebral Activation

    ERIC Educational Resources Information Center

    Takeuchi, Osamu; Ikeda, Maiko; Mizumoto, Atsushi

    2012-01-01

    This article explores the cerebral mechanism of reading aloud activities in L2 learners. These activities have been widely used in L2 learning and teaching, and its effect has been reported in various Asian L2 learning contexts. However, the reasons for its effectiveness have not been examined. In order to fill in this gap, two studies using a…

  7. 101 Environmental Education Activities. Booklet 3--Mathematics Activities.

    ERIC Educational Resources Information Center

    Schaljo, Roger, Comp.

    Each of the 14 environment-related mathematics activities included in this publication by the Upper Mississippi River ECO-Center includes objectives, materials needed, preparation, and activity description. Occasionally, variations and helpful hints are added. Because the student can gain experience to help him with the practical application of…

  8. Active microrheology in active matter systems: Mobility, intermittency, and avalanches.

    PubMed

    Reichhardt, C; Reichhardt, C J Olson

    2015-03-01

    We examine the mobility and velocity fluctuations of a driven particle moving through an active matter bath of self-mobile disks for varied density or area coverage and varied activity. We show that the driven particle mobility can exhibit nonmonotonic behavior that is correlated with distinct changes in the spatiotemporal structures that arise in the active media. We demonstrate that the probe particle velocity distributions exhibit specific features in the different dynamic regimes and identify an activity-induced uniform crystallization that occurs for moderate activity levels and is distinct from the previously observed higher activity cluster phase. The velocity distribution in the cluster phase has telegraph noise characteristics produced when the probe particle moves alternately through high-mobility areas that are in the gas state and low-mobility areas that are in the dense phase. For higher densities and large activities, the system enters what we characterize as an active jamming regime. Here the probe particle moves in intermittent jumps or avalanches that have power-law-distributed sizes that are similar to the avalanche distributions observed for nonactive disk systems near the jamming transition.

  9. Basic Business and Economics: Varied Activities Encourage Active Student Involvement.

    ERIC Educational Resources Information Center

    Baker, Robert Lee, Jr.

    1978-01-01

    Describes a variety of activities for the basic business classroom, such as having guest speakers, question-and-answer sessions, simulations, role playing, debates, small group work, field trips, games, and individualized instruction. Includes a report of business teachers' knowledge of and attitudes toward these activities. (MF)

  10. Incorporation of Socio-scientific Content into Active Learning Activities

    NASA Astrophysics Data System (ADS)

    King, D. B.; Lewis, J. E.; Anderson, K.; Latch, D.; Sutheimer, S.; Webster, G.; Moog, R.

    2014-12-01

    Active learning has gained increasing support as an effective pedagogical technique to improve student learning. One way to promote active learning in the classroom is the use of in-class activities in place of lecturing. As part of an NSF-funded project, a set of in-class activities have been created that use climate change topics to teach chemistry content. These activities use the Process Oriented Guided Inquiry Learning (POGIL) methodology. In this pedagogical approach a set of models and a series of critical thinking questions are used to guide students through the introduction to or application of course content. Students complete the activities in their groups, with the faculty member as a facilitator of learning. Through assigned group roles and intentionally designed activity structure, process skills, such as teamwork, communication, and information processing, are developed during completion of the activity. Each of these climate change activities contains a socio-scientific component, e.g., social, ethical and economic data. In one activity, greenhouse gases are used to explain the concept of dipole moment. Data about natural and anthropogenic production rates, global warming potential and atmospheric lifetimes for a list of greenhouse gases are presented. The students are asked to identify which greenhouse gas they would regulate, with a corresponding explanation for their choice. They are also asked to identify the disadvantages of regulating the gas they chose in the previous question. In another activity, where carbon sequestration is used to demonstrate the utility of a phase diagram, students use economic and environmental data to choose the best location for sequestration. Too often discussions about climate change (both in and outside the classroom) consist of purely emotional responses. These activities force students to use data to support their arguments and hypothesize about what other data could be used in the corresponding discussion to

  11. Fluidization and Active Thinning by Molecular Kinetics in Active Gels

    NASA Astrophysics Data System (ADS)

    Oriola, David; Alert, Ricard; Casademunt, Jaume

    2017-02-01

    We derive the constitutive equations of an active polar gel from a model for the dynamics of elastic molecules that link polar elements. Molecular binding kinetics induces the fluidization of the material, giving rise to Maxwell viscoelasticity and, provided that detailed balance is broken, to the generation of active stresses. We give explicit expressions for the transport coefficients of active gels in terms of molecular properties, including nonlinear contributions on the departure from equilibrium. In particular, when activity favors linker unbinding, we predict a decrease of viscosity with activity—active thinning—of kinetic origin, which could explain some experimental results on the cell cortex. By bridging the molecular and hydrodynamic scales, our results could help understand the interplay between molecular perturbations and the mechanics of cells and tissues.

  12. Active Volcanism on Io: Global Distribution and Variations in Activity

    USGS Publications Warehouse

    Lopes-Gautier, R.; McEwen, A.S.; Smythe, W.B.; Geissler, P.E.; Kamp, L.; Davies, A.G.; Spencer, J.R.; Keszthelyi, L.; Carlson, R.; Leader, F.E.; Mehlman, R.; Soderblom, L.

    1999-01-01

    Io's volcanic activity has been monitored by instruments aboard the Galileo spacecraft since June 28, 1996. We present results from observations by the near-infrared mapping spectrometer (NIMS) for the first 10 orbits of Galileo, correlate them with results from the Solid State Imaging System (SSI) and from groundbased observations, and compare them to what was known about Io's volcanic activity from observations made during the two Voyager flybys in 1979. A total of 61 active volcanic centers have been identified from Voyager, groundbased, and Galileo observations. Of these, 41 are hot spots detected by NIMS and/or SSI. Another 25 locations were identified as possible active volcanic centers, mostly on the basis of observed surface changes. Hot spots are correlated with surface colors, particularly dark and red deposits, and generally anti-correlated with white, SO2-rich areas. Surface features corresponding to the hot spots, mostly calderas or flows, were identified from Galileo and Voyager images. Hot spot temperatures obtained from both NIMS and SSI are consistent with silicate volcanism, which appears to be widespread on Io. Two types of hot spot activity are present: persistent-type activity, lasting from months to years, and sporadic events, which may represent either short-lived activity or low-level activity that occasionally flares up. Sporadic events are not often detected, but may make an important contribution to Io's heat flow and resurfacing. The distribution of active volcanic centers on the surface does not show any clear correlation with latitude, longitude, Voyager-derived global topography, or heat flow patterns predicted by the asthenosphere and deep mantle tidal dissipation models. However, persistent hot spots and active plumes are concentrated toward lower latitudes, and this distribution favors the asthenosphere rather than the deep mantle tidal dissipation model. ?? 1999 Academic Press.

  13. Protease activities of rumen protozoa.

    PubMed Central

    Forsberg, C W; Lovelock, L K; Krumholz, L; Buchanan-Smith, J G

    1984-01-01

    Intact, metabolically active rumen protozoa prepared by gravity sedimentation and washing in a mineral solution at 10 to 15 degrees C had comparatively low proteolytic activity on azocasein and low endogenous proteolytic activity. Protozoa washed in 0.1 M potassium phosphate buffer (pH 6.8) at 4 degrees C and stored on ice autolysed when they were warmed to 39 degrees C. They also exhibited low proteolytic activity on azocasein, but they had a high endogenous proteolytic activity with a pH optimum of 5.8. The endogenous proteolytic activity was inhibited by cysteine proteinase inhibitors, for example, iodoacetate (63.1%) and the aspartic proteinase inhibitor, pepstatin (43.9%). Inhibitors specific for serine proteinases and metalloproteinases were without effect. The serine and cysteine proteinase inhibitors of microbial origin, including antipain, chymostatin, and leupeptin, caused up to 67% inhibition of endogenous proteolysis. Hydrolysis of casein by protozoa autolysates was also inhibited by cysteine proteinase inhibitors. Some of the inhibitors decreased endogenous deamination, in particular, phosphoramidon, which had little inhibitory effect on proteolysis. Protozoal and bacterial preparations exhibited low hydrolytic activities on synthetic proteinase and carboxypeptidase substrates, although the protozoa had 10 to 78 times greater hydrolytic activity (per milligram of protein) than bacteria on the synthetic aminopeptidase substrates L-leucine-p-nitroanilide, L-leucine-beta-naphthylamide, and L-leucinamide. The aminopeptidase activity was partially inhibited by bestatin. It was concluded that cysteine proteinases and, to a lesser extent, aspartic proteinases are primarily responsible for proteolysis in autolysates of rumen protozoa. The protozoal autolysates had high aminopeptidase activity; low deaminase activity was observed on endogenous amino acids. PMID:6364968

  14. NSLS 2009 Activity Report

    SciTech Connect

    Nasta K.; Mona R.

    2009-05-01

    2009 was an incredibly exciting year for light sources at Brookhaven. The National Synchrotron Light Source (NSLS) hosted more than 2,200 visiting researchers, who, along with the about 50 members of our scientific staff, produced a total of 957 publications - about 20 percent of which appeared in premier journals. Covering topics ranging from Alzheimer's disease detection to ethanol-powered fuel cells, a sampling of these findings can be found in this Activity Report. We've also seen the resurfacing of some of our long-time users hard work. I was very proud to hear that two of the three recipients of the 2009 Nobel Prize in Chemistry have ties to the NSLS. Venki Ramakrishnan, a former employee in Brookhaven's biology department and long-time user of the NSLS, now at Cambridge University, and Thomas A. Steitz of Yale University, also a long-time NSLS user, shared the prize with Ada E. Yonath of the Weizmann Institute of Science for their work on the structure and function of the ribosome. In the late 1990s, Ramakrishnan and Steitz used protein crystallography at the NSLS to gather atomic-level images of two ribosome subunits: 30S (Ramakrishnan) and 50S (Steitz). Both laureates solved the high-resolution structures for these subunits based on this data. After struggling with a rough budget for several years, we received excellent funding, and then some, this year. In addition to NSLS operations funding, we received $3 million in funds from the American Recovery and Reinvestment Act (ARRA). We used that additional money for two exciting projects: construction of a full-field x-ray microscope and acquisition of several advanced x-ray detectors. The x-ray microscope will be able to image objects with a targeted spatial resolution of 30 nanometers. This capability will be particularly important for new initiatives in energy research and will prepare our users for the projected 1-nanometer resolution benchmark at the National Synchrotron Light Source II (NSLS-II). The

  15. World Cultures through Art Activities.

    ERIC Educational Resources Information Center

    Robinson, Dindy

    The guide is intended to be a supplement to multicultural units in primary grades. The activities are freehand and students should be encouraged to use their imaginations and ideas to improve on a design. The approach is based on a whole language philosophy of learning with simple art activities that encourage creativity and critical thinking in…

  16. Interdisciplinarity in Adapted Physical Activity

    ERIC Educational Resources Information Center

    Bouffard, Marcel; Spencer-Cavaliere, Nancy

    2016-01-01

    It is commonly accepted that inquiry in adapted physical activity involves the use of different disciplines to address questions. It is often advanced today that complex problems of the kind frequently encountered in adapted physical activity require a combination of disciplines for their solution. At the present time, individual research…

  17. Outdoor Recreation Activities at Cispus.

    ERIC Educational Resources Information Center

    Cispus Environmental Center, Randle, WA.

    Most of the activities in this booklet have been developed around skills related to the outdoors and, in particular, to the logging industry and forest fire fighting. The activities attempt to develop muscles, coordination skills, and teamwork. They also give the students (junior high school or high school) and staff the opportunity to do…

  18. Antimicrobial activity of Securidaca longipedunculata.

    PubMed

    Ajali, U; Chukwurah, B K C

    2004-11-01

    The folk herbal uses of Securidaca longipedunculata in the treatment of diarrhea, boils, gonorrhea, and cough prompted phytochemical analyses and antimicrobial activity screening of extracts of the root. Some flavonoids isolated showed activity against many micro-organisms. These flavonoids were isolated using chromatographic methods.

  19. Getting Active in the Classroom

    ERIC Educational Resources Information Center

    Yerigan, Tanya

    2008-01-01

    This paper presents active learning theory and how implementation of dynamic instruction strategies can transform the K-12 classroom. A multi-part study was conducted to determine both the level of active learning knowledge among participants and applicability of newly acquired approaches within the participants' classrooms. First, teachers were…

  20. Cancer, physical activity, and exercise.

    PubMed

    Brown, Justin C; Winters-Stone, Kerri; Lee, Augustine; Schmitz, Kathryn H

    2012-10-01

    This review examines the relationship between physical activity and cancer along the cancer continuum, and serves as a synthesis of systematic and meta-analytic reviews conducted to date. There exists a large body of epidemiologic evidence that conclude those who participate in higher levels of physical activity have a reduced likelihood of developing a variety of cancers compared to those who engage in lower levels of physical activity. Despite this observational evidence, the causal pathway underlying the association between participation in physical activity and cancer risk reduction remains unclear. Physical activity is also a useful adjunct to improve the deleterious sequelae experienced during cancer treatment. These deleterious sequelae may include fatigue, muscular weakness, deteriorated functional capacity, and many others. The benefits of physical activity during cancer treatment are similar to those experienced after treatment. Despite the growing volume of literature examining physical activity and cancer across the cancer continuum, a number of research gaps exist. There is little evidence on the safety of physical activity among all cancer survivors, as most trials have selectively recruited participants. The specific dose of exercise needed to optimize primary cancer prevention or symptom control during and after cancer treatment remains to be elucidated.