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Sample records for relaxed muscles behave

  1. Vertical dimonsion changes after muscle relaxation

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    Shahroodi MH

    1998-09-01

    Full Text Available In this study, 116 edentulous patients in the age group 37-90 yrs were selected. Out of the above,"n12 patients had visited the dept. Of prosthodontics for the first time for treatment. Other 34 of them were"npatients of the dental school and the rest were from Kahrizak and Nikan sanatoriums."nInitially, the V.D. of rest was measured as usual for all the patients. After subjecting them to the excercises of completely opening and closing of the mouth for 15 no. of times, the rest position was measured again. Results show that the changes in V.D.R. after, excercises, relaxing the elevator and depressor muscles and the duration of usage of prosthesis, the following conclusions are obtained."n1. There is an increase in V.D.R. after tiring out the elevator and depressor muscles of the jaws."n2. There is a direct co - relation between the increased V.D.R. and duration of use of prosthesis after excercises."n3. Change in the V.D.R. after excercise is notably more in women."n4. No definite conclusion is obtained in the relationship between changes in V.D.R. after excercises and use of prosthesis during sleep."n5. As above no conclusions as yet can be deduced between changes in V.D.R. and different operators.

  2. The effects of progressive muscle relaxation and autogenic relaxation on young soccer players' mood states.

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    Hashim, Hairul Anuar; Hanafi Ahmad Yusof, Hazwani

    2011-06-01

    This study was designed to compare the effects of two different relaxation techniques, namely progressive muscle relaxation (PMR) and autogenic relaxation (AGR) on moods of young soccer players. sixteen adolescent athletes (mean age: 14.1 ± 1.3) received either PMR or AGR training. Using Profile of Mood States- Adolescents, their mood states were measured one week before relaxation training, before the first relaxation session, and after the twelfth relaxation session. Mixed ANOVA revealed no significant interaction effects and no significant main effects in any of the subscales. However, significant main effects for testing sessions were found for confusion, depression, fatigue, and tension subscales. Post hoc tests revealed post-intervention reductions in the confusion, depression, fatigue, and tension subscale scores. These two relaxation techniques induce equivalent mood responses and may be used to regulate young soccer players' mood states.

  3. The Effects of Progressive Muscle Relaxation and Autogenic Relaxation on Young Soccer Players’ Mood States

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    Hashim, Hairul Anuar; Hanafi@Ahmad Yusof, Hazwani

    2011-01-01

    Purpose This study was designed to compare the effects of two different relaxation techniques, namely progressive muscle relaxation (PMR) and autogenic relaxation (AGR) on moods of young soccer players. Methods Sixteen adolescent athletes (mean age: 14.1 ± 1.3) received either PMR or AGR training. Using Profile of Mood States- Adolescents, their mood states were measured one week before relaxation training, before the first relaxation session, and after the twelfth relaxation session. Results Mixed ANOVA revealed no significant interaction effects and no significant main effects in any of the subscales. However, significant main effects for testing sessions were found for confusion, depression, fatigue, and tension subscales. Post hoc tests revealed post-intervention reductions in the confusion, depression, fatigue, and tension subscale scores. Conclusion These two relaxation techniques induce equivalent mood responses and may be used to regulate young soccer players’ mood states. PMID:22375225

  4. Experimental model of human corpus cavernosum smooth muscle relaxation

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    Rommel P. Regadas

    2010-08-01

    Full Text Available PURPOSE: To describe a technique for en bloc harvesting of the corpus cavernosum, cavernous artery and urethra from transplant organ donors and contraction-relaxation experiments with corpus cavernosum smooth muscle. MATERIALS AND METHODS: The corpus cavernosum was dissected to the point of attachment with the crus penis. A 3 cm segment (corpus cavernosum and urethra was isolated and placed in ice-cold sterile transportation buffer. Under magnification, the cavernous artery was dissected. Thus, 2 cm fragments of cavernous artery and corpus cavernosum were obtained. Strips measuring 3 x 3 x 8 mm3 were then mounted vertically in an isolated organ bath device. Contractions were measured isometrically with a Narco-Biosystems force displacement transducer (model F-60, Narco-Biosystems, Houston, TX, USA and recorded on a 4-channel Narco-Biosystems desk model polygraph. RESULTS: Phenylephrine (1µM was used to induce tonic contractions in the corpus cavernosum (3 - 5 g tension and cavernous artery (0.5 - 1g tension until reaching a plateau. After precontraction, smooth muscle relaxants were used to produce relaxation-response curves (10-12M to 10-4 M. Sodium nitroprusside was used as a relaxation control. CONCLUSION: The harvesting technique and the smooth muscle contraction-relaxation model described in this study were shown to be useful instruments in the search for new drugs for the treatment of human erectile dysfunction.

  5. [Central muscle relaxant activities of 2-methyl-3-aminopropiophenone derivatives].

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    Kontani, H; Mano, A; Koshiura, R; Yamazaki, M; Shimada, Y; Oshita, M; Morikawa, K; Kato, H; Ito, Y

    1987-02-01

    In this experiment, we synthetized new 2-methyl-3-aminopropiophenone (MP) derivatives, whose structure is known to have central muscle relaxant activities, and quinolizidine and indan . tetralin derivatives derived from MP by cyclization, and we investigated the central muscle relaxant activity. Among the quinolizidine derivatives, there was a very strong central depressant agent, trans (3H, 9aH)-3-(p-chloro) benzoyl-quinolizidine (HSR-740), and among the indan . tetralin derivatives, there was an excitant agents, trans (1H, 2H)-5-methoxy-3, 3-dimethyl-2-piperidinomethyl indan-1-ol (HSR-719). From the results, these derivatives were not considered to be adequate for central muscle relaxant. Among the MP derivatives, (4'-chloro-2'-methoxy-3-piperidino) propiophenone HCl (HSR-733) and (4'-ethyl-2-methyl-3-pyrrolidino) propiophenone HCl (HSR-770) strongly inhibited the cooperative movement in the rotating rod method using mice, and it exerted almost the same depressant activity on the cross extensor reflex using alpha-chloralose anesthetized rats. However, the inhibitory effects of HSR-733 on the anemic decerebrate rigidity and the rigidity induced by intracollicular decerebration in rats were weaker than those of HSR-770 and eperisone. In spinal cats, at a low dose (5 mg/kg, i.v.), HSR-733 depressed monosynaptic and dorsal root reflex potentials as compared with polysynaptic reflex potentials, and inhibitory effects of HSR-733 on these three reflex potentials were more potent than those of eperisone and HSR-770. Although HSR-770 acts on the spinal cord and supraspinal level on which eperisone has been reported to act, HSR-733 may mainly act on the spinal cord. These results indicate that the MP derivative with a 2-methyl group may be suitable as a central muscle relaxant. HSR-770, which has equipotent muscle relaxant activity to eperisone, exerted strong inhibitory effects on oxotremorine-induced tremor and weak inhibitory effects on spontaneous motor activity in the

  6. Spectroscopic Studies of the Super Relaxed State of Skeletal Muscle.

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    Leonardo Nogara

    Full Text Available In the super-relaxed state of myosin, ATPase activity is strongly inhibited by binding of the myosin heads to the core of the thick filament in a structure known as the interacting-heads motif. In the disordered relaxed state myosin heads are not bound to the core of the thick filament and have an ATPase rate that is 10 fold greater. In the interacting-heads motif the two regulatory light chains appear to bind to each other. We have made single cysteine mutants of the regulatory light chain, placed both paramagnetic and fluorescent probes on them, and exchanged them into skinned skeletal muscle fibers. Many of the labeled light chains tended to disrupt the stability of the super-relaxed state, and showed spectral changes in the transition from the disordered relaxed state to the super-relaxed state. These data support the putative interface between the two regulatory light chains identified by cryo electron microscopy and show that both the divalent cation bound to the regulatory light chain and the N-terminus of the regulatory light chain play a role in the stability of the super-relaxed state. One probe showed a shift to shorter wavelengths in the super-relaxed state such that a ratio of intensities at 440nm to that at 520nm provided a measure of the population of the super-relaxed state amenable for high throughput screens for finding potential pharmaceuticals. The results provide a proof of concept that small molecules that bind to this region can destabilize the super-relaxed state and provide a method to search for small molecules that do so leading to a potentially effective treatment for Type 2 diabetes and obesity.

  7. Repeatability and reliability of muscle relaxation properties induced by motor cortical stimulation.

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    Molenaar, Joery P; Voermans, Nicol C; de Jong, Lysanne A; Stegeman, Dick F; Doorduin, Jonne; van Engelen, Baziel G

    2018-03-15

    Impaired muscle relaxation is a feature of many neuromuscular disorders. However, there are few tests available to quantify muscle relaxation. Transcranial magnetic stimulation (TMS) of the motor cortex can induce muscle relaxation by abruptly inhibiting corticospinal drive. The aim of our study is to investigate if repeatability and reliability of TMS-induced relaxation is greater than voluntary relaxation. Furthermore, effects of sex, cooling and fatigue on muscle relaxation properties were studied. Muscle relaxation of deep finger flexors was assessed in twenty-five healthy subjects (14 M and 11 F, aged 39.1{plus minus}12.7 and 45.3{plus minus}8.7 years old, respectively) using handgrip dynamometry. All outcome measures showed greater repeatability and reliability in TMS-induced relaxation compared to voluntary relaxation. The within-subject coefficient of variability of normalized peak relaxation rate was lower in TMS-induced relaxation than in voluntary relaxation (3.0 vs 19.7% in men, and 6.1 vs 14.3% in women). The repeatability coefficient was lower (1.3 vs 6.1 s -1 in men and 2.3 vs 3.1 s -1 in women), and the intraclass correlation coefficient was higher (0.95 vs 0.53 in men and 0.78 vs 0.69 in women), for TMS-induced relaxation compared to voluntary relaxation. TMS enabled to demonstrate slowing effects of sex, muscle cooling, and muscle fatigue on relaxation properties that voluntary relaxation could not. In conclusion, repeatability and reliability of TMS-induced muscle relaxation was greater compared to voluntary muscle relaxation. TMS-induced muscle relaxation has the potential to be used in clinical practice for diagnostic purposes and therapy effect monitoring in patients with impaired muscle relaxation.

  8. Sedative and muscle relaxant activities of diterpenoids from Phlomidoschema parviflorum

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    Abdur Rauf

    Full Text Available Abstract Phlomidoschema parviflorum (Benth. Vved. (Basionym: Stachys parviflora Benth. Lamiaceae, have significance medicinal importance as it is used in number of health disorders including diarrhea, fever, sore mouth and throat, internal bleeding, weaknesses of the liver and heart genital tumors, sclerosis of the spleen, inflammatory tumors and cancerous ulcers. The present contribution deals with the sedative and muscle relaxant like effects of diterpenoids trivially named stachysrosane and stachysrosane, isolated from the ethyl acetate soluble fraction of P. parviflorum. Both compounds (at 5, 10 and 15 mg/kg, i.p were assessed for their in vivo sedative and muscle relaxant activity in open field and inclined plane test, respectively. The geometries of both compounds were optimized with density functional theory. The molecular docking of both compounds were performed with receptor gamma aminobutyric acid. Both compounds showed marked activity in a dose dependent manner. The docking studies showed that both compounds interact strongly with important residues in receptor gamma aminobutyric acid. The reported data demonstrate that both compounds exhibited significant sedative and muscle relaxant-like effects in animal models, which opens a door for novel therapeutic applications.

  9. An electromyographic study of muscle relaxants in man.

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    Suzuki, H; Kanayama, T; Nakagawa, H; Yazaki, S; Shiratsuchi, T

    1975-05-01

    Supramaximal paired stimuli were applied to the ulnar nerve, and the amplitude of the muscle action potential evoked in the abductor digiti minimi by the second member of the stimulus pair (test response) was compared with that evoked by the first component (conditioning response). The interval between the two components of the stimulus pair (the pair interval) was increased stepwise from 7 to 100 msec and a curve (recovery curve) was obtained by relating the changes in pair interval to the difference in amplitude of the test and conditioning responses. Alterations of the recovery curve (RC) during partial paralysis by muscle relaxants were investigated in healthy adult patients under the lightest plane of general anaesthesia. The control curve obtained in 32 subjects before the administration of a muscle relaxant drug was characterized by slight depressions at very short intervals of paired stimuli, followed by a slight potentiation at 20-100 msec. With non-depolarizing relaxants, RC altered to the characteristic pattern of potentiation at very short intervals of stimuli, followed by a notable depression at longer intervals. In depolarizing blocks with small doses of suxamethonium, the depression of RC at short intervals in the control was enhanced and the pattern of RC was different from that of non-depolarizing agents. When desensitization blocks were instigated by the i.v. administration of suxamethonium, the RC patterns were similar to those of competitive agents.

  10. Quantitative evaluation of muscle relaxation induced by Kundalini yoga with the help of EMG integrator.

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    Narayan, R; Kamat, A; Khanolkar, M; Kamat, S; Desai, S R; Dhume, R A

    1990-10-01

    The present work is aimed to quantify the degree of relaxation of muscle under the effects of Kundalini Yoga with the help of EMG integrator. The data collected from 8 individuals (4 males 4 females) on the degree of muscle relaxation at the end of meditation revealed a significantly decreased muscle activity amounting to 58% of the basal level in both the sexes.

  11. HSP20 phosphorylation and airway smooth muscle relaxation

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    Mariam Ba

    2009-06-01

    Full Text Available Mariam Ba1, Cherie A Singer1, Manoj Tyagi2, Colleen Brophy3, Josh E Baker4, Christine Cremo4, Andrew Halayko5, William T Gerthoffer21Department of Pharmacology, University of Nevada School of Medicine, Reno, NV, USA; 2Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL, USA; 3Harrington Department of Biochemistry, Arizona State University, Tempe, AZ, USA; 4Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA; 5Departments of Physiology and Internal Medicine, University of Manitoba, Winnipeg, MB, CanadaAbstract: HSP20 (HSPB6 is a small heat shock protein expressed in smooth muscles that is hypothesized to inhibit contraction when phosphorylated by cAMP-dependent protein kinase. To investigate this hypothesis in airway smooth muscle (ASM we showed that HSP20 was constitutively expressed as well as being inducible in cultured hASM cells by treatment with 1 µM isoproterenol or 10 µM salmeterol. In contrast, a mixture of proinflammatory mediators (interleukin-1β, tumor necrosis factor α, and interferon γ inhibited expression of HSP20 by about 50% in 48 hours. To determine whether phosphorylation of HSP20 is sufficient to induce relaxation, canine tracheal smooth muscle was treated with a cell permeant phosphopeptide that mimics the phosphorylation of HSP20. The HSP20 phosphopeptide antagonized carbacholinduced contraction by 60% with no change in myosin light chain phosphorylation. Recombinant full length HSP20 inhibited skeletal actin binding to smooth muscle myosin subfragment 1 (S1, and recombinant cell permeant TAT-HSP20 S16D mutant reduced F-actin filaments in cultured hASM cells. Carbachol stimulation of canine tracheal smooth muscle tissue caused redistribution of HSP20 from large macromolecular complexes (200–500 kDa to smaller complexes (<60 kDa. The results are consistent with HSP20 expression and macromolecular structure being dynamically regulated in airway

  12. Oxygen mediates vascular smooth muscle relaxation in hypoxia.

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    Jessica Dada

    Full Text Available The activation of soluble guanylate cyclase (sGC by nitric oxide (NO and other ligands has been extensively investigated for many years. In the present study we considered the effect of molecular oxygen (O2 on sGC both as a direct ligand and its affect on other ligands by measuring cyclic guanosine monophosphate (cGMP production, as an index of activity, as well as investigating smooth muscle relaxation under hypoxic conditions. Our isolated enzyme studies confirm the function of sGC is impaired under hypoxic conditions and produces cGMP in the presence of O2, importantly in the absence of NO. We also show that while O2 could partially affect the magnitude of sGC stimulation by NO when the latter was present in excess, activation by the NO independent, haem-dependent sGC stimulator 3-(5'-hydroxymethyl-2'-furyl-1-benzylindazole (YC-1 was unaffected. Our in vitro investigation of smooth muscle relaxation confirmed that O2 alone in the form of a buffer bolus (equilibrated at 95% O2/5% CO2 had the ability to dilate vessels under hypoxic conditions and that this was dependent upon sGC and independent of eNOS. Our studies confirm that O2 can be a direct and important mediator of vasodilation through an increase in cGMP production. In the wider context, these observations are key to understanding the relative roles of O2 versus NO-induced sGC activation.

  13. Gamma dosimetric parameters in some skeletal muscle relaxants

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    Manjunatha, H. C.

    2017-09-01

    We have studied the attenuation of gamma radiation of energy ranging from 84 keV to 1330 keV (^{170}Tm, ^{22}Na,^{137}Cs, and ^{60}Co) in some commonly used skeletal muscle relaxants such as tubocurarine chloride, gallamine triethiodide, pancuronium bromide, suxamethonium bromide and mephenesin. The mass attenuation coefficient is measured from the attenuation experiment. In the present work, we have also proposed the direct relation between mass attenuation coefficient (μ /ρ ) and mass energy absorption coefficient (μ _{en}/ρ ) based on the nonlinear fitting procedure. The gamma dosimetric parameters such as mass energy absorption coefficient (μ _{en}/ρ ), effective atomic number (Z_{eff}), effective electron density (N_{el}), specific γ-ray constant, air kerma strength and dose rate are evaluated from the measured mass attentuation coefficient. These measured gamma dosimetric parameters are compared with the theoretical values. The measured values agree with the theoretical values. The studied gamma dosimetric values for the relaxants are useful in medical physics and radiation medicine.

  14. Multivariate analysis of electrical impedance spectra for relaxed and contracted skeletal muscle

    International Nuclear Information System (INIS)

    Zagar, T; Krizaj, D

    2008-01-01

    Four-electrode impedance spectra of relaxed and contracted muscle biceps brachii were analyzed in an adult human subject over the frequency range from 300 Hz to 75 kHz. A feasibility of the principal component analysis of bioimpedance measurement for the evaluation of skeletal muscle contractile state was examined. The principal components score plots show a data grouping of the impedance spectra from the two muscle groups. The classification was performed using a soft independent modeling of class analogy (SIMCA) method. The data set comprised 32 samples (16 samples of contracted muscle and 16 samples of relaxed muscle). The leave-one-out test of the classification yields about 80% of correctly classified samples (11 samples for contracted and 15 samples for relaxed muscle)

  15. MUSCLE RELAXANTS: ARE THEY NEEDED IN ANKYLOSING SPONDYLITIS?

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    T. V. Dubinina

    2016-01-01

    Full Text Available Guidelines for the treatment of ankylosing spondylitis (AS lack muscle relaxants. At the same time, the latter are used for combined therapy using nonsteroidal  anti-inflammatory drugs (NSAIDs  in 53.1% of patients in an outpatient  setting. No clear recommendations make the administration of these agents uncontrolled, on the one hand, and substantially restrict therapeutic  possibilities, on the other.Objective: to investigate the short-term effect and safety of using tolperisone hydrochloride  (THC,  Mydocalm®  in patients with AS during group therapeutic  exercise (TE.Subjects and methods. The investigation included 40 patients aged over 18 years with a valid diagnosis of AS who had been treated at the Clinic of the V.A. Nasonova Research Institute of Rheumatology and agreed to participate  in the study. All the patients were randomized  in a 1:1 ratio into two groups: 1 20 patients used NSAIDs in combination with TE; 2 20 patients received NSAIDs,  TE, and THC 450 mg/day. The groups were matched for age, gender, disease duration,  and functional impairments. Before and after completion  of the investigation, the investigators estimated BASDAI, BASFI, patient-rated numerical pain rating scale (NPRS, patient-rated TE performance  scores (NPRS, where 0 (very effective, 10 (ineffective, THC tolerance monitoring  (consideration of adverse events. Spinal motility was evaluated using BASMI and chest excursion measurement.Results and discussion. During TE, both groups showed a significant increase in the volume of movements (p < 0.03, when measuring chest excursion and carrying out modified Schober's test, a decrease in BASDAI (p < 0.01 and BASFI (p < 0.009, as well as a reduction  in patient-rated overall disease activity assessment (p < 0.02 as compared to the baseline values. At the same time the modified Schober test revealed that the increase in motility was significantly higher in Group 2 than in Group 1 (p < 0.05. During the

  16. In vivo antinociceptive and muscle relaxant activity of leaf and bark of Buddleja asiatica L.

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    Barkatullah, -; Ibrar, Muhammad; Ikram, Nazia; Rauf, Abdur; Hadda, Taibi Ben; Bawazeer, Saud; Khan, Haroon; Pervez, Samreen

    2016-09-01

    The current study was designed to assess the antinociceptive and skeleton muscle relaxant effect of leaves and barks of Buddleja asiatica in animal models. In acetic acid induced writhing test, pretreatment of ethanolic extract of leaves and barks evoked marked dose dependent antinociceptive effect with maximum of 70% and 67% pain relief at 300mg/kg i.p. respectively. In chimney test, the ethanolic extract of leaves and barks evoked maximum of 66.66% and 53.33% muscle relaxant effect after 90min of treatment at 300mg/kg i.p respectively. In traction test, the ethanolic extract of leaves and barks caused maximum of 60% and 73.33% muscle relaxant effect after 90min of treatment at 300mg/kg i.p respectively. In short, both leaves and barks demonstrated profound antinociceptive and skeleton muscle relaxant effects and thus the study provided natural healing agents for the treatment of said disorders.

  17. Arginase strongly impairs neuronal nitric oxide-mediated airway smooth muscle relaxation in allergic asthma

    NARCIS (Netherlands)

    Maarsingh, H; Leusink, J; Bos, I Sophie T; Zaagsma, J; Meurs, H

    2006-01-01

    Background: Using guinea pig tracheal preparations, we have recently shown that endogenous arginase activity attenuates inhibitory nonadrenergic noncholinergic (iNANC) nerve-mediated airway smooth muscle relaxation by reducing nitric oxide (NO) production - due to competition with neuronal

  18. Control of muscle relaxation during anesthesia: a novel approach for clinical routine.

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    Stadler, Konrad S; Schumacher, Peter M; Hirter, Sibylle; Leibundgut, Daniel; Bouillon, Thomas W; Glattfelder, Adolf H; Zbinden, Alex M

    2006-03-01

    During general anesthesia drugs are administered to provide hypnosis, ensure analgesia, and skeletal muscle relaxation. In this paper, the main components of a newly developed controller for skeletal muscle relaxation are described. Muscle relaxation is controlled by administration of neuromuscular blocking agents. The degree of relaxation is assessed by supramaximal train-of-four stimulation of the ulnar nerve and measuring the electromyogram response of the adductor pollicis muscle. For closed-loop control purposes, a physiologically based pharmacokinetic and pharmacodynamic model of the neuromuscular blocking agent mivacurium is derived. The model is used to design an observer-based state feedback controller. Contrary to similar automatic systems described in the literature this controller makes use of two different measures obtained in the train-of-four measurement to maintain the desired level of relaxation. The controller is validated in a clinical study comparing the performance of the controller to the performance of the anesthesiologist. As presented, the controller was able to maintain a preselected degree of muscle relaxation with excellent precision while minimizing drug administration. The controller performed at least equally well as the anesthesiologist.

  19. Smooth muscle relaxant activity of Crocus sativus (saffron and its constituents: possible mechanisms

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    Amin Mokhtari-Zaer

    2015-08-01

    Full Text Available Saffron, Crocus sativus L. (C. sativus is rich in carotenoids and used in traditional medicine for treatment of various conditions such as coughs, stomach disorders, amenorrhea, asthma and cardiovascular disorders. These therapeutic effects of the plant are suggested to be due to its relaxant effect on smooth muscles. The effect of C. sativus and its constituents on different smooth muscles and the underlying mechanisms have been studied. Several studies have shown the relaxant effects of C. sativus and its constituents including safranal, crocin, crocetin and kaempferol on blood vessels. In addition, it was reported that saffron stigma lowers systolic blood pressure. The present review highlights the relaxant effects of C. sativus and its constituents on various smooth muscles. The possible mechanisms of this relaxing effect including activation of ß2-adrenoceptors, inhibition of histamine H1 and muscarinic receptors and calcium channels and modulation of nitric oxide (NO are also reviewed.

  20. Effects of zoxazolamine and related centrally acting muscle relaxants on nigrostriatal dopaminergic neurons.

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    Matthews, R T; McMillen, B A; Speciale, S G; Jarrah, H; Shore, P A; Sanghera, M K; Shepard, P D; German, D C

    1984-05-01

    The effects of zoxazolamine (ZOX) and related centrally acting muscle relaxants on striatal dopamine (DA) metabolism and turnover, and substantia nigra zona compacta DA neuronal impulse flow were studied in rats. ZOX, chlorzoxazone and mephenesin, but not meprobamate, chloral hydrate, diazepam, pentobarbital, ethanol or dantrolene, decreased striatal DA metabolism without affecting striatal DA concentrations. More specifically, ZOX, as a representative muscle relaxant, was shown to decrease striatal DA turnover without directly affecting DA synthesis, catabolism, reuptake, or release. ZOX decreased nigral DA neuronal firing rates and dramatically decreased firing rate variability (normally many of the cells fire with bursting firing patterns but after ZOX the cells often fired with a very regular pacemaker-like firing pattern). ZOX and related centrally acting muscle relaxants appear to decrease striatal DA turnover by decreasing both neuronal firing rate and firing rate variability. The possible relationships between DA neuronal activity and muscle tone are discussed.

  1. Synthesis and photodegradation studies of analogues of muscle relaxant 1,4-dihydropyridine compounds

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    Gündüz Miyase Gözde

    2017-09-01

    Full Text Available This paper describes the synthesis of 1,4-dihydropyridine compounds (DHPs endowed with good muscle relaxant activity and stability to light. Six new condensed DHPs were synthesized by the microwave irradiation method. A long-chain ester moiety [2-(methacryloyloxyethyl] and various substituents on the phenyl ring were demonstrated to affect the muscle relaxant activity occurring in isolated rabbit gastric fundus smooth muscle strips. Forced photodegradation conditions were applied to the molecules according to the ICH rules. The degradation profile of the drugs was monitored by spectrophotometry coupled with the multivariate curve resolution technique. Formation of the oxidized pyridine derivative was observed for all the studied DHPs, except for one compound, which showed very fast degradation and formation of a second photo-product. Pharmacological tests on the molecules showed a good muscle relaxing effect, with a mechanism similar to that of nifedipine, however, proving to be more stable to light.

  2. β-adrenergic relaxation of smooth muscle: differences between cells and tissues

    International Nuclear Information System (INIS)

    Scheid, C.R.

    1987-01-01

    The present studies were carried out in an attempt to resolve the controversy about the Na + dependence of β-adrenergic relaxation in smooth muscle. Previous studies on isolated smooth muscle cells from the toad stomach had suggested that at least some of the actions of β-adrenergic agents, including a stimulatory effect on 45 Ca efflux, were dependent on the presence of a normal transmembrane Na + gradient. Studies by other investigators using tissues derived from mammalian sources had suggested that the relaxing effect of β-adrenergic agents was Na + independent. Uncertainty remained as to whether these discrepancies reflected differences between cells and tissues or differences between species. Thus, in the present studies, the authors utilized both tissues and cells from the same source, the stomach muscle of the toad Bufo marinus, and assessed the Na + dependence of β-adrenergic relaxation. They found that elimination of a normal Na + gradient abolished β-adrenergic relaxation of isolated cells. In tissues, however, similar manipulations had no effect on relaxation. The reasons for this discrepancy are unclear but do not appear to be attributable to changes in smooth muscle function following enzymatic dispersion. Thus the controversy concerning the mechanisms of β-adrenergic relaxation may reflect inherent differences between tissues and cells

  3. Effect of an Ethanol Extract of Scutellaria baicalensis on Relaxation in Corpus Cavernosum Smooth Muscle

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    Xiang Li

    2012-01-01

    Full Text Available Aims of study. The aim of the present study was to investigate whether an ethanol extract of Scutellaria baicalensis (ESB relaxes penile corpus cavernosum muscle in organ bath experiments. Materials and methods. Changes in tension of cavernous smooth muscle strips were determined by penile strip chamber model and in penile perfusion model. Isolated endothelium-intact rabbit corpus cavernosum was precontracted with phenylephrine (PE and then treated with ESB. Results. ESB relaxed penile smooth muscle in a dose-dependent manner, and this was inhibited by pre-treatment with NG-nitro-l-arginine methyl ester (l-NAME, a nitric oxide (NO synthase inhibitor, and 1H-[1, 2, 4]-oxadiazolo-[4,3-α]-quinoxalin-1-one (ODQ, a soluble guanylyl cyclase (sGC inhibitor. ESB-induced relaxation was significantly attenuated by pretreatment with tetraethylammonium (TEA, a nonselective K+ channel blocker, and charybdotoxin, a selective Ca2+-dependent K+ channel inhibitor. ESB increased the cGMP levels of rabbit corpus cavernosum in a concentration-dependent manner without changes in cAMP levels. In a perfusion model of penile tissue, ESB also relaxed penile corpus cavernosum smooth muscle in a dose-dependent manner. Conclusion. Taken together, these results suggest that ESB relaxed rabbit cavernous smooth muscle via the NO/cGMP system and Ca2+-sensitive K+ channels in the corpus cavernosum.

  4. Muscle relaxation for individuals having tattoos removed through laser treatment: possible effects regarding anxiety and pain.

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    Huang, Faye; Chou, Wen-Jiun; Chen, Tien-Hsing; Chen, Ching; Hsieh, Yu-Lian; Chong, Mian-Yoon; Hung, Chi-Fa; Lin, Shu-Ching; Tsai, Hsiu-Huang; Wang, Liang-Jen

    2016-08-01

    Effectively managing pain is vital for the well-being and satisfaction of patients undergoing dermatologic treatments involving lasers. This study investigates the potential outcome of using muscle relaxation techniques to reduce pain among people having their tattoos removed with laser treatment. This study consists of 56 participants (mean age 18.1 ± 2.1 years) that had tattoos removed using the principle of selective photothermolysis. These participants underwent muscle relaxation before receiving the laser treatment. Their peripheral skin temperatures (PST) were measured both at the beginning and the end of the muscle relaxation period. Then, the Beck Anxiety Inventory was applied to evaluate anxiety levels. Once the laser treatment was completed, pain levels were measured using a visual analogue scale. A total of 125 person-sessions of laser treatment and psychometric assessments were performed in this study. The muscle relaxation method significantly increased the PST of the participants while reducing the levels of anxiety and pain throughout the course of the laser treatment procedure. The PST, anxiety scores, and pain scores all showed significant correlations with one another. According to the results obtained, this study proposes that muscle relaxation techniques be considered possibly auxiliary treatment options for individuals having tattoos removed through laser treatment. Additional studies with a comparison group and a larger sample size are required in the future to confirm the effectiveness of such intervention.

  5. Smooth muscle relaxant activity of 3- carbomethoxylpyridine from ...

    African Journals Online (AJOL)

    This was achieved by subjecting the compound to uterine preparation in an organ bath containing a physiological salt solution of De Jalon. The contractions were recorded with an FT03 transducer attached to an Ugo Basil recorder. The study has shown for the first time that 3-carbomethoxylpyridine has a relaxant effect on ...

  6. Effect of Progressive Muscle Relaxation on the Adverse ...

    African Journals Online (AJOL)

    of PCOS patients and their influence on the cardiovascular risk factors. ... and relaxation therapies may be recommended as an adjuvant therapy, to tilt the autonomic balance to .... The fall in systolic pressure was taken as the result of orthostatic tolerance test (OTT). ... period. Group B (control group) received treatment only.

  7. The Effects of Progressive Muscle Relaxation and Guided Imagery on gestational hypertension

    OpenAIRE

    Ranjkesh F

    2017-01-01

    Introduction: Hypertension is a common disorder in pregnancy. Although this disorder is accompanied by many difficulties in pregnancy, no effective therapy has still been found to treat it. One of the main methods in the treatment of hypertension is stress reducing programs such as relaxation and Guided Imagery. This study is aimed to evaluate the effects of progressive muscle relaxation and guided imagery on the gestational hypertension. Methods: The present study is a randomized clinical...

  8. Logarithmic superposition of force response with rapid length changes in relaxed porcine airway smooth muscle.

    Science.gov (United States)

    Ijpma, G; Al-Jumaily, A M; Cairns, S P; Sieck, G C

    2010-12-01

    We present a systematic quantitative analysis of power-law force relaxation and investigate logarithmic superposition of force response in relaxed porcine airway smooth muscle (ASM) strips in vitro. The term logarithmic superposition describes linear superposition on a logarithmic scale, which is equivalent to multiplication on a linear scale. Additionally, we examine whether the dynamic response of contracted and relaxed muscles is dominated by cross-bridge cycling or passive dynamics. The study shows the following main findings. For relaxed ASM, the force response to length steps of varying amplitude (0.25-4% of reference length, both lengthening and shortening) are well-fitted with power-law functions over several decades of time (10⁻² to 10³ s), and the force response after consecutive length changes is more accurately fitted assuming logarithmic superposition rather than linear superposition. Furthermore, for sinusoidal length oscillations in contracted and relaxed muscles, increasing the oscillation amplitude induces greater hysteresivity and asymmetry of force-length relationships, whereas increasing the frequency dampens hysteresivity but increases asymmetry. We conclude that logarithmic superposition is an important feature of relaxed ASM, which may facilitate a more accurate prediction of force responses in the continuous dynamic environment of the respiratory system. In addition, the single power-function response to length changes shows that the dynamics of cross-bridge cycling can be ignored in relaxed muscle. The similarity in response between relaxed and contracted states implies that the investigated passive dynamics play an important role in both states and should be taken into account.

  9. Selective reversal of muscle relaxation in general anesthesia: focus on sugammadex

    Directory of Open Access Journals (Sweden)

    Sorin J Brull

    2009-04-01

    Full Text Available Sorin J Brull1, Mohamed Naguib21Department of Anesthesiology, Mayo Clinic College of Medicine, Mayo Clinic Hospital, Jacksonville, FL, USA; 2Department of Anesthesiology and Pain Medicine, The University of Texas M D Anderson Cancer Center,  Houston, TX, USAAbstract: Despite the significant improvements in the pharmacology of muscle relaxants in the past six decades, the search for the ideal muscle relaxant continues, mainly because of the incomplete efficacy and persistent side effects associated with their antagonism. Clinical concerns remain about the residual paralysis and hemodynamic side effects associated with the classic pharmacologic reversal agents, the acetylcholinesterase inhibitors. Although the development of the “ideal muscle relaxant” remains illusory, pharmacologic advancements hold promise for improved clinical care and patient safety. Recent clinical advances include the development of short-acting nondepolarizing muscle relaxant agents that have fast onset and a very rapid metabolism that allows reliable and complete recovery; and the development of selective, “designer” reversal agents that are specific for a single drug or class of drugs. This article reviews recent developments in the pharmacology of these selective reversal agents: plasma cholinesterases, cysteine, and sugammadex. Although each of the selective reversal agents is specific in its substrate, the clinical use of the combination of muscle relaxant with its specific reversal agent will allow much greater intraoperative titrating ability, decreased side effect profile, and may result in a decreased incidence of postoperative residual paralysis and improved patient safety.Keywords: selective reversal agents, cysteine, plasma cholinesterases, sugammadex

  10. Relaxing action of adrenergic β2-agonists on guinea-pig skinned tracheal muscle

    Directory of Open Access Journals (Sweden)

    Kayo Nemoto

    1999-01-01

    Full Text Available Although adrenergic β2-agonist-induced smooth muscle relaxation has been attributed to increased intracellular cyclic AMP (cAMP, a relaxation response has been observed at low β2-agonist concentrations that do not cause increased cAMP To elucidate the mechanism of tracheal muscle relaxation induced by low concentrations of β2-agonists, we used a guinea-pig skinned tracheal smooth muscle preparation to examine the effects on the contractile protein system. The isotonic contraction of β-escin-treated skinned tracheal muscle from guinea-pig was measured. When the intracellular Ca2+ concentration was maintained at 1 μmol/L in the presence of guanosine 5′-triphosphate (GTP; 100 μmol/L, neither isoproterenol (10nmol/L nor salbutamol (60 nmol/L affected Ca2+ sensitivity, but a significant decrease in Ca2+ sensitivity was observed in the presence of okadaic acid (1 μmol/L. The decrease in Ca2+ sensitivity was a slow response and was blocked by pretreatment with propranolol (1 μmol/L. Forskolin (1 μmol/L did not affect Ca2+ sensitivity. These results suggest that adrenergic b 2-agonists may activate protein phosphatase through an unknown pathway involving the β2-receptor, which enhances dephosphorylation of the myosin light chain and/or thin filament proteins, resulting in relaxation of the tracheal smooth muscle.

  11. Electromechanical delay components during skeletal muscle contraction and relaxation in patients with myotonic dystrophy type 1.

    Science.gov (United States)

    Esposito, Fabio; Cè, Emiliano; Rampichini, Susanna; Limonta, Eloisa; Venturelli, Massimo; Monti, Elena; Bet, Luciano; Fossati, Barbara; Meola, Giovanni

    2016-01-01

    The electromechanical delay during muscle contraction and relaxation can be partitioned into mainly electrochemical and mainly mechanical components by an EMG, mechanomyographic, and force combined approach. Component duration and measurement reliability were investigated during contraction and relaxation in a group of patients with myotonic dystrophy type 1 (DM1, n = 13) and in healthy controls (n = 13). EMG, mechanomyogram, and force were recorded in DM1 and in age- and body-matched controls from tibialis anterior (distal muscle) and vastus lateralis (proximal muscle) muscles during maximum voluntary and electrically-evoked isometric contractions. The electrochemical and mechanical components of the electromechanical delay during muscle contraction and relaxation were calculated off-line. Maximum strength was significantly lower in DM1 than in controls under both experimental conditions. All electrochemical and mechanical components were significantly longer in DM1 in both muscles. Measurement reliability was very high in both DM1 and controls. The high reliability of the measurements and the differences between DM1 patients and controls suggest that the EMG, mechanomyographic, and force combined approach could be utilized as a valid tool to assess the level of neuromuscular dysfunction in this pathology, and to follow the efficacy of pharmacological or non-pharmacological interventions. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Effect of Progressive Muscle Relaxation on Social Performance and Quality of Life in Aging

    Directory of Open Access Journals (Sweden)

    Ali Hassanpour Dehkordi

    2016-07-01

    Conclusion: The findings of this study revealed that the progressive muscle relaxation technique can effectively reduce the duration of rehabilitation, days of hospitalization and healthcare costs, as well as improve the quality of life, mood, and mental health in the elderly people.

  13. The effect of progressive muscle relaxation techniques on anxiety in Patients with myocardial infarction

    Directory of Open Access Journals (Sweden)

    Mozhgan Jariani

    2011-12-01

    Conclusion: progressive muscle relaxation can reduce the amount of anxiety, and systolic and diastolic blood pressure of the patients with myocardial infarction hospitalized in CCU ward, therefore it can play an effective role as a supplement non-medicinal, simple and cheap treatment for these patients

  14. Effect of Progressive Muscle Relaxation on the Fatigue and Quality of Life Among Iranian Aging Persons

    Directory of Open Access Journals (Sweden)

    Ali Hassanpour-Dehkordi

    2016-07-01

    Full Text Available Since the elderly population is increasing rapidly in developing countries which may decrease the physical activity and exercise and in turn could affect the elderly’s quality of life, this study aimed to investigate the effect of progressive muscle relaxation on the elderly’s quality of life in Iran. In a randomized clinical trial, participants were randomly divided into intervention and control groups. For the intervention group, muscular progressive relaxation was run three days per week for three months (totally 36 sessions. In relaxation, a patient contract a group of his/her muscles in each step and relaxes them after five seconds and finally loosens all muscles and takes five deep breaths. Each session lasts for 45 minutes. The instrument of data gathering consisted of questionnaires on individual’s demographic data and quality of life SF-36. After intervention, quality of life increased significantly in the patients undergoing muscular progressive relaxation and fatigue severity decreased significantly in the intervention group compared to prior to intervention. In addition, there was a statistically significant difference in mean score of physical performance, restricted activity after physical problem, energy, socially function, physical pain, overall hygiene, and quality of life between intervention and control groups. By implementing regular and continuous progressive muscle relaxation, quality of life could be increased in different dimensions in the elderly and the context could be provided to age healthily and enjoy higher health and autonomy. Therefore, all of the therapeutic staffs are recommended to implement this plan to promote the elderly’s quality of life.

  15. Acrolein relaxes mouse isolated tracheal smooth muscle via a TRPA1-dependent mechanism.

    Science.gov (United States)

    Cheah, Esther Y; Burcham, Philip C; Mann, Tracy S; Henry, Peter J

    2014-05-01

    Airway sensory C-fibres express TRPA1 channels which have recently been identified as a key chemosensory receptor for acrolein, a toxic and highly prevalent component of smoke. TRPA1 likely plays an intermediary role in eliciting a range of effects induced by acrolein including cough and neurogenic inflammation. Currently, it is not known whether acrolein-induced activation of TRPA1 produces other airway effects including relaxation of mouse airway smooth muscle. The aims of this study were to examine the effects of acrolein on airway smooth muscle tone in mouse isolated trachea, and to characterise the cellular and molecular mechanisms underpinning the effects of acrolein. Isometric tension recording studies were conducted on mouse isolated tracheal segments to characterise acrolein-induced relaxation responses. Release of the relaxant PGE₂ was measured by EIA to examine its role in the response. Use of selective antagonists/inhibitors permitted pharmacological characterisation of the molecular and cellular mechanisms underlying this relaxation response. Acrolein induced dose-dependent relaxation responses in mouse isolated tracheal segments. Importantly, these relaxation responses were significantly inhibited by the TRPA1 antagonists AP-18 and HC-030031, an NK₁ receptor antagonist RP-67580, and the EP₂ receptor antagonist PF-04418948, whilst completely abolished by the non-selective COX inhibitor indomethacin. Acrolein also caused rapid PGE₂ release which was suppressed by HC-030031. In summary, acrolein induced a novel bronchodilator response in mouse airways. Pharmacologic studies indicate that acrolein-induced relaxation likely involves interplay between TRPA1-expressing airway sensory C-fibres, NK₁ receptor-expressing epithelial cells, and EP₂-receptor expressing airway smooth muscle cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Comparison of sensory modes of biofeedback in relaxation training of frontalis muscle.

    Science.gov (United States)

    Chen, W

    1981-12-01

    The purpose of this study was to compare the effectiveness of various sensory modes of EMG biofeedback to relaxation training of the frontalis muscle. 19 male and 29 female subjects were randomly selected from a pool of college volunteers. They were then randomly assigned 12 each to audiofeedback, visual feedback, audiovisual feedback, and no feedback groups. There were 11 20-min. sessions per subject. Subjects in the biofeedback groups were trained to reduce muscle tension voluntarily by utilizing Cyborg J33 EMG portable trainers. The subjects in the three feedback groups exhibited significantly lower muscle tension than did the subjects in the no-feedback control group. There were no significant differences in relaxation among the three feedback groups.

  17. Relaxation time T/sub 1/ and bound water fraction of muscle by NMR imager

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, N.; Ikehira, H.; Yamane, T.; Tateno, Y.; Torii, S.; Matsumura, K.

    1986-05-01

    In order to establish the efficacy of NMR-CT in the diagnostic investigation of muscle disorders, proton NMR-CT imaging was performed and muscle longitudinal relaxation (T1) times were measured in 20 Duchenne muscular dystrophy (DMD) patients and normal controls (NC). In addition, the bound water fraction (BWF) was calculated from the measured T1 value in appropriate cases. Results show that in DMD muscle T1 values were above normal in the early clinical stages, declined rapidly with progress of the disease, and reached the same low level as the subcutaneous fat. This decrease of T1 values was not uniform for all muscles, being most prominent in gluteus maximus and least in sartorius and gracilis. In NC muscle BWF increased with maturation under the age of 10 years, and became fixed beyond that. In the early stages of DMD, BWF was below normal.

  18. Azemiopsin, a Selective Peptide Antagonist of Muscle Nicotinic Acetylcholine Receptor: Preclinical Evaluation as a Local Muscle Relaxant

    Directory of Open Access Journals (Sweden)

    Irina V. Shelukhina

    2018-01-01

    Full Text Available Azemiopsin (Az, a linear peptide from the Azemiops feae viper venom, contains no disulfide bonds, is a high-affinity and selective inhibitor of nicotinic acetylcholine receptor (nAChR of muscle type and may be considered as potentially applicable nondepolarizing muscle relaxant. In this study, we investigated its preclinical profile in regard to in vitro and in vivo efficacy, acute and chronic toxicity, pharmacokinetics, allergenic capacity, immunotoxicity and mutagenic potency. The peptide effectively inhibited (IC50 ~ 19 nM calcium response of muscle nAChR evoked by 30 μM (EC100 acetylcholine but was less potent (IC50 ~ 3 μM at α7 nAChR activated by 10 μM (EC50 acetylcholine and had a low affinity to α4β2 and α3-containing nAChR, as well as to GABAA or 5HT3 receptors. Its muscle relaxant effect was demonstrated at intramuscular injection to mice at doses of 30–300 µg/kg, 30 µg/kg being the initial effective dose and 90 µg/kg—the average effective dose. The maximal muscle relaxant effect of Az was achieved in 10 min after the administration and elimination half-life of Az in mice was calculated as 20–40 min. The longest period of Az action observed at a dose of 300 µg/kg was 55 min. The highest acute toxicity (LD50 510 μg/kg was observed at intravenous injection of Az, at intramuscular or intraperitoneal administration it was less toxic. The peptide showed practically no immunotoxic, allergenic or mutagenic capacity. Overall, the results demonstrate that Az has good drug-like properties for the application as local muscle relaxant and in its parameters, is not inferior to the relaxants currently used. However, some Az modification might be effective to extend its narrow therapeutic window, a typical characteristic and a weak point of all nondepolarizing myorelaxants.

  19. Flexion relaxation of the hamstring muscles during lumbar-pelvic rhythm.

    Science.gov (United States)

    Sihvonen, T

    1997-05-01

    This study investigated the simultaneous activity of back muscles and hamstring muscles during sagittal forward body flexion and extension in healthy persons. The study was cross-sectional. A descriptive study of paraspinal and hamstring muscle activity in normal persons during lumbar-pelvic rhythm. A university hospital. Forty healthy volunteers (21 men, 19 women, ages 17 to 48 years), all without back pain or other pain syndromes. Surface electromyography (EMG) was used to follow activities in the back and the hamstring muscles. With movement sensors, real lumbar flexion was separated from simultaneous pelvic motion by monitoring the components of motion with a two-inclinometer method continuously from the initial upright posture into full flexion. All signals were sampled during real-time monitoring for off-line analyses. Back muscle activity ceased (ie, flexion relaxation [FR] occurred) at lumbar flexion with a mean of 79 degrees. Hamstring activity lasted longer and EMG activity ceased in the hamstrings when nearly full lumbar flexion (97%) was reached. After this point total flexion and pelvic flexion continued further, so that the last part of lumbar flexion and the last part of pelvic flexion happened without back muscle activity or hamstring bracing, respectively. FR of the back muscles during body flexion has been well established and its clinical significance in low back pain has been confirmed. In this study, it was shown for the first time that the hip extensors (ie, hamstring muscles) relax during forward flexion but with different timing. FR in hamstrings is not dependent on or coupled firmly with back muscle behavior in spinal disorders and the lumbar pelvic rhythm can be locally and only partially disturbed.

  20. Evidence of direct smooth muscle relaxant effects of the fibrate gemfibrozil.

    Science.gov (United States)

    Phelps, Laura E; Peuler, Jacob D

    2010-01-01

    Fibrates are commonly employed to treat abnormal lipid metabolism via their unique ability to stimulate peroxisome proliferator-activated receptor alpha (PPARalpha). Interestingly, they also decrease systemic arterial pressure, despite recent evidence that PPAR alpha may contribute to expression of renin and related hypertension. Yet, mechanisms responsible for their potential antihypertensive activity remain unresolved. Rapid decreases in arterial pressure following bolus intravenous injections of bezafibrate strongly suggest they may relax arterial smooth muscle directly. But since bezafibrate is highly susceptible to photodegradation in aqueous media, it has never been critically tested for this possibility in vitro with isolated arterial smooth muscle preparations. Accordingly, we tested gemfibrozil which is resistant to photodegradation. We examined it over a therapeutically-relevant range (50-400 microM) for both acute and delayed relaxant effects on contractions of the isolated rat tail artery; contractions induced by either depolarizing its smooth muscle cell membranes with high potassium or stimulating its membrane-bound receptors with norepinephrine and arginine-vasopressin. We also examined these same gemfibrozil levels for effects on spontaneously-occurring phasic rhythmic contractile activity, typically not seen in arteries under in vitro conditions but commonly exhibited by smooth muscle of uterus, duodenum and bladder. We found that gemfibrozil significantly relaxed all induced forms of contraction in the rat tail artery, acutely at the higher test levels and after a delay of a few hours at the lower test levels. The highest test level of gemfibrozil (400 microM) also completely abolished spontaneously-occurring contractile activity of the isolated uterus and duodenum and markedly suppressed it in the bladder. This is the first evidence that a fibrate drug can directly relax smooth muscle contractions, either induced by various contractile agents or

  1. Sodium pump activity and calcium relaxation in vascular smooth muscle of deoxycorticosterone acetate-salt rats

    International Nuclear Information System (INIS)

    Soltis, E.E.; Field, F.P.

    1986-01-01

    The Na + -K + pump activity was determined in femoral arterial smooth muscle from deoxycorticosterone acetate (DOCA)-salt hypertensive rats using potassium relaxation and ouabain-sensitive 86 Rb uptake as indices. The membrane-stabilizing effect of calcium and its relation to Na + -K + pump activity also were examined. Femoral arteries from DOCA-salt rats exhibited a greater relaxation in response to potassium addition after contraction with norepinephrine in a low potassium (0.6 mM) Krebs solution. The concentration of potassium required to produce a 50% relaxation was significantly less in DOCA-salt rats. Ouabain-sensitive 86 Rb uptake was significantly greater at 3, 10, and 20 minutes of 86 Rb incubation in femoral arteries from DOCA-salt rats. Linear regression analysis revealed a significant correlation between the uptake of 86 Rb and time of incubation in both control and DOCA-salt rats. A significant difference in the slopes of the regression lines showed that the rate of uptake was greater in DOCA-salt rats. No difference was observed in ouabain-insensitive 86 Rb uptake. A dose-dependent relaxation in response to increasing concentrations of calcium following contraction to norepinephrine was observed in femoral arteries from control and DOCA-salt rats. The relaxation was directly dependent on the level of extracellular potassium and was blocked by ouabain. Femoral arteries from DOCA-salt rats relaxed to a significantly greater extent in response to calcium at each level of potassium when compared with controls. These results provide further evidence for an increase in Na + -K + pump activity in vascular smooth muscle from DOCA-salt hypertensive rats

  2. PROGRESSIVE MUSCLE RELAXATION INCREASE PEAK EXPIRATORY FLOW RATE ON CHRONIC OBSTRUCTIVE PULMONARY DISEASE PATIENTS

    Directory of Open Access Journals (Sweden)

    Tintin Sukartini

    2017-07-01

    Full Text Available Introduction: Limited progressive air flow in Chronic Obstructive Pulmonary Disease (COPD can caused by small airway disease (bronchiolitis obstructive and loss of elasticity of the lung (emphysema. Further it can be decreasing the quality of life in COPD patients because dyspnea and uncomfortable in activity. Progressive muscle relaxation (PMR is one of the relaxation technique that can repair pulmonary ventilation by decreasing chronic constriction of the respiratory muscles. The objective of this study was to analyze the effect of progressive muscle relaxation on raised peak expiratory flow rate (PEFR. Method: A pre-experimental one group pre-post test design was used in this study. Population was all of the COPD patients at Pulmonary Specialist Polyclinic Dr Mohamad Soewandhie Surabaya. There were 8 respondents taken by using purposive sampling. PEFR was counted by using peak flow meter every six day. Data were analyzed by using Paired t-Test with significance level  p≤0.05. Result: The result showed that PMR had significance level on increasing of PEFR (p=0.012. Discussion: It can be concluded that PMR has an effect on raise PEFR. Further studies are recommended to measure the effect of PMR on respiratory rate (RR, heart rate (HR subjective dyspnoe symptoms, forced expiration volume on the first minute (FEV1 and mid maximum flow rate (MMFR in COPD patients.

  3. Bifunctional Rhodamine Probes of Myosin Regulatory Light Chain Orientation in Relaxed Skeletal Muscle Fibers

    Science.gov (United States)

    Brack, Andrew S.; Brandmeier, Birgit D.; Ferguson, Roisean E.; Criddle, Susan; Dale, Robert E.; Irving, Malcolm

    2004-01-01

    The orientation of the regulatory light chain (RLC) region of the myosin heads in relaxed skinned fibers from rabbit psoas muscle was investigated by polarized fluorescence from bifunctional rhodamine (BR) probes cross-linking pairs of cysteine residues introduced into the RLC. Pure 1:1 BR-RLC complexes were exchanged into single muscle fibers in EDTA rigor solution for 30 min at 30°C; ∼60% of the native RLC was removed and stoichiometrically replaced by BR-RLC, and >85% of the BR-RLC was located in the sarcomeric A-bands. The second- and fourth-rank order parameters of the orientation distributions of BR dipoles linking RLC cysteine pairs 100-108, 100-113, 108-113, and 104-115 were calculated from polarized fluorescence intensities, and used to determine the smoothest RLC orientation distribution—the maximum entropy distribution—consistent with the polarized fluorescence data. Maximum entropy distributions in relaxed muscle were relatively broad. At the peak of the distribution, the “lever” axis, linking Cys707 and Lys843 of the myosin heavy chain, was at 70–80° to the fiber axis, and the “hook” helix (Pro830–Lys843) was almost coplanar with the fiber and lever axes. The temperature and ionic strength of the relaxing solution had small but reproducible effects on the orientation of the RLC region. PMID:15041671

  4. Repeated sugammadex reversal of muscle relaxation during lumbar spine surgery with intraoperative neurophysiological multimodal monitoring.

    Science.gov (United States)

    Errando, C L; Blanco, T; Díaz-Cambronero, Ó

    2016-11-01

    Intraoperative neurophysiological monitoring during spine surgery is usually acomplished avoiding muscle relaxants. A case of intraoperative sugammadex partial reversal of the neuromuscular blockade allowing adequate monitoring during spine surgery is presented. A 38 year-old man was scheduled for discectomy and vertebral arthrodesis throughout anterior and posterior approaches. Anesthesia consisted of total intravenous anesthesia plus rocuronium. Intraoperatively monitoring was needed, and the muscle relaxant reverted twice with low dose sugammadex in order to obtain adequate responses. The doses of sugammadex used were conservatively selected (0.1mg/kg boluses increases, total dose needed 0.4mg/kg). Both motor evoqued potentials, and electromyographic responses were deemed adequate by the neurophysiologist. If muscle relaxation was needed in the context described, this approach could be useful to prevent neurological sequelae. This is the first study using very low dose sugammadex to reverse rocuronium intraoperatively and to re-establish the neuromuscular blockade. Copyright © 2016 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  5. PPARα-Independent Arterial Smooth Muscle Relaxant Effects of PPARα Agonists

    Directory of Open Access Journals (Sweden)

    Neerupma Silswal

    2012-01-01

    Full Text Available We sought to determine direct vascular effects of peroxisome proliferator-activated receptor alpha (PPARα agonists using isolated mouse aortas and middle cerebral arteries (MCAs. The PPARα agonists GW7647, WY14643, and gemfibrozil acutely relaxed aortas held under isometric tension and dilated pressurized MCAs with the following order of potency: GW7647≫WY14643>gemfibrozil. Responses were endothelium-independent, and the use of PPARα deficient mice demonstrated that responses were also PPARα-independent. Pretreating arteries with high extracellular K+ attenuated PPARα agonist-mediated relaxations in the aorta, but not in the MCA. In the aorta, the ATP sensitive potassium (KATP channel blocker glibenclamide also impaired relaxations whereas the other K+ channel inhibitors, 4-aminopyridine and Iberiotoxin, had no effect. In aortas, GW7647 and WY14643 elevated cGMP levels by stimulating soluble guanylyl cyclase (sGC, and inhibition of sGC with ODQ blunted relaxations to PPARα agonists. In the MCA, dilations were inhibited by the protein kinase C (PKC activator, phorbol 12,13-dibutyrate, and also by ODQ. Our results demonstrated acute, nonreceptor-mediated relaxant effects of PPARα agonists on smooth muscle of mouse arteries. Responses to PPARα agonists in the aorta involved KATP channels and sGC, whereas in the MCA the PKC and sGC pathways also appeared to contribute to the response.

  6. Skeletal muscle relaxant effect of a standardized extract of Valeriana officinalis L. after acute administration in mice

    Directory of Open Access Journals (Sweden)

    Dorian Caudal

    2018-04-01

    Full Text Available Valeriana officinalis L. root extracts are traditionally taken for their sedative and anxiolytic properties and are also used for muscle relaxation. Relaxant effects were clearly observed on smooth muscle whereas data on effects on skeletal muscle are scarce and inconsistent. The aim of this study was to assess whether a standardized extract (SE of V. officinalis had myorelaxant effects by decreasing skeletal muscle strength and/or neuromuscular tone in mice. Mice received an acute dose of V. officinalis SE (2 or 5 g/kg per os or tetrazepam (10 mg/kg ip, a standard myorelaxant drug. Thirty minutes later, the maximal muscle strength was measured using a grip test, while global skeletal muscle function (endurance and neuromuscular tone was assessed in a wire hanging test. Compared to tetrazepam, both doses of V. officinalis SE induced a pronounced decrease in skeletal muscle strength without any significant effects on endurance and neuromuscular tone. This study provides clear evidence that the extract of V. officinalis tested has a relaxant effect on skeletal muscle. By decreasing skeletal muscle strength without impacting endurance and neuromuscular tone, V. officinalis SE could induce less undesirable side effects than standard myorelaxant agents, and be particularly useful for avoiding falls in the elderly. Keywords: Valeriana officinalis, Skeletal muscle relaxant, Strength, Hydroethanolic root extract, Acute treatment, Mouse

  7. Arginase strongly impairs neuronal nitric oxide-mediated airway smooth muscle relaxation in allergic asthma

    Directory of Open Access Journals (Sweden)

    Zaagsma Johan

    2006-01-01

    Full Text Available Abstract Background Using guinea pig tracheal preparations, we have recently shown that endogenous arginase activity attenuates inhibitory nonadrenergic noncholinergic (iNANC nerve-mediated airway smooth muscle relaxation by reducing nitric oxide (NO production – due to competition with neuronal NO-synthase (nNOS for the common substrate, L-arginine. Furthermore, in a guinea pig model of allergic asthma, airway arginase activity is markedly increased after the early asthmatic reaction (EAR, leading to deficiency of agonist-induced, epithelium-derived NO and subsequent airway hyperreactivity. In this study, we investigated whether increased arginase activity after the EAR affects iNANC nerve-derived NO production and airway smooth muscle relaxation. Methods Electrical field stimulation (EFS; 150 mA, 4 ms, 4 s, 0.5 – 16 Hz-induced relaxation was measured in tracheal open-ring preparations precontracted to 30% with histamine in the presence of 1 μM atropine and 3 μM indomethacin. The contribution of NO to EFS-induced relaxation was assessed by the nonselective NOS inhibitor Nω-nitro-L-arginine (L-NNA, 100 μM, while the involvement of arginase activity in the regulation of EFS-induced NO production and relaxation was investigated by the effect of the specific arginase inhibitor Nω-hydroxy-nor-L-arginine (nor-NOHA, 10 μM. Furthermore, the role of substrate availability to nNOS was measured in the presence of exogenous L-arginine (5.0 mM. Results At 6 h after ovalbumin-challenge (after the EAR, EFS-induced relaxation (ranging from 3.2 ± 1.1% at 0.5 Hz to 58.5 ± 2.2% at 16 Hz was significantly decreased compared to unchallenged controls (7.1 ± 0.8% to 75.8 ± 0.7%; P P P Conclusion The results clearly demonstrate that increased arginase activity after the allergen-induced EAR contributes to a deficiency of iNANC nerve-derived NO and decreased airway smooth muscle relaxation, presumably via increased substrate competition with nNOS.

  8. In vivo measurements of T1 relaxation times of 31P-metabolites in human skeletal muscle

    DEFF Research Database (Denmark)

    Thomsen, C; Jensen, K E; Henriksen, O

    1989-01-01

    The T1 relaxation times were estimated for 31P-metabolites in human skeletal muscle. Five healthy volunteers were examined in a 1.5 Tesla wholebody imaging system using an inversion recovery pulse sequence. The calculated T1 relaxation times ranged from 5.517 sec for phosphocreatine to 3.603 sec...

  9. The Effect of Progressive Muscle Relaxation on The Occupational Stress of Nurses in Critical Care Units

    Directory of Open Access Journals (Sweden)

    Pegah Matourypour

    2012-10-01

    Full Text Available Background and objective: In the nursing profession, there are numerous factors which altogether cause occupational stress and as a result occupational exhaustion in nurses and decrease the quality of patient care. Regarding the importance of this issue which influences the health indices of the society, this study investigates the effect of progressive muscle relaxation on the occupational stress of nurses.Materials and Methods: This semi-experimental and before-after study was conducted using progressive muscle relaxation intervention on 33 nurses in special treatment (ICU and CCU and emergency units through simple sampling in Yazd in 2012. To assess occupational stress,Toft-Anderson questionnaire was used. The procedure of applying relaxation in a practical way was given to nurses in pamphlets and questionnaires were filled before and two weeks after the intervention. Analysis was done using SPSS.16 software and T-test.Results: The average total score of stress in nurses before and after the intervention was determined as – 28.12±43.74 and 52.12±04.72 respectively and this difference was not statistically significant (39.0>p. However, in the dimensions of nurses’ workload (/0>p 03 and t=2.27 and patients’ suffering and death, these scores were significantly different (0001.0>p and t=3.94.Conclusion: This study showed that applying progressive muscle relaxation technique as a method of emotion-focused coping cannot be effective in the reduction of occupational stress in nurses.

  10. Effect of cycling on oxygenation of relaxed neck/shoulder muscles in women with and without chronic pain

    DEFF Research Database (Denmark)

    Andersen, Lars L; Blangsted, Anne Katrine; Nielsen, Pernille Kofoed

    2010-01-01

    Work-related neck/shoulder muscle pain has been associated with increased anaerobic muscle metabolism. Thus, interventions to enhance oxygenation of painful muscles seem relevant. While cycling with relaxed shoulders has been shown to result in acute neck/shoulder muscle pain reduction, the effect...... on tissue oxygenation remains unknown. The aim of the present study was to investigate tissue oxygenation of the passive trapezius muscle during and after cycling in female workers with (MYA) and without (CON) trapezius myalgia. Eligible participants (n = 17 MYA, n = 8 CON) performed 20 min sub...... increases oxygenation of resting neck/shoulder muscles in women with and without trapezius myalgia, indicating acute positive effects of either neural or humoral factors on vascular beds of distant relaxed muscles. Although this beneficial response was observed in both groups, the post-exercise response...

  11. Pharmacological characterization of the relaxant effect induced by adrenomedullin in rat cavernosal smooth muscle

    International Nuclear Information System (INIS)

    Leite, L.N.; Gonzaga, N.A.; Tirapelli, D.P.C.; Tirapelli, L.F.; Tirapelli, C.R.

    2014-01-01

    The aim of the present study was to determine the mechanisms underlying the relaxant effect of adrenomedullin (AM) in rat cavernosal smooth muscle (CSM) and the expression of AM system components in this tissue. Functional assays using standard muscle bath procedures were performed in CSM isolated from male Wistar rats. Protein and mRNA levels of pre-pro-AM, calcitonin receptor-like receptor (CRLR), and Subtypes 1, 2 and 3 of the receptor activity-modifying protein (RAMP) family were assessed by Western immunoblotting and quantitative real-time polymerase chain reaction, respectively. Nitrate and 6-keto-prostaglandin F 1α (6-keto-PGF 1α ; a stable product of prostacyclin) levels were determined using commercially available kits. Protein and mRNA of AM, CRLR, and RAMP 1, -2, and -3 were detected in rat CSM. Immunohistochemical assays demonstrated that AM and CRLR were expressed in rat CSM. AM relaxed CSM strips in a concentration-dependent manner. AM 22-52 , a selective antagonist for AM receptors, reduced the relaxation induced by AM. Conversely, CGRP 8-37 , a selective antagonist for calcitonin gene-related peptide receptors, did not affect AM-induced relaxation. Preincubation of CSM strips with N G -nitro-L-arginine-methyl-ester (L-NAME, nitric oxide synthase inhibitor), 1H-(1,2,4)oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, quanylyl cyclase inhibitor), Rp-8-Br-PET-cGMPS (cGMP-dependent protein kinase inhibitor), SC560 [5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethyl pyrazole, selective cyclooxygenase-1 inhibitor], and 4-aminopyridine (voltage-dependent K + channel blocker) reduced AM-induced relaxation. On the other hand, 7-nitroindazole (selective neuronal nitric oxide synthase inhibitor), wortmannin (phosphatidylinositol 3-kinase inhibitor), H89 (protein kinase A inhibitor), SQ22536 [9-(tetrahydro-2-furanyl)-9H-purin-6-amine, adenylate cyclase inhibitor], glibenclamide (selective blocker of ATP-sensitive K + channels), and apamin (Ca 2+ -activated

  12. Pharmacological characterization of the relaxant effect induced by adrenomedullin in rat cavernosal smooth muscle

    Energy Technology Data Exchange (ETDEWEB)

    Leite, L.N. [Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Laboratório de Farmacologia, Departamento de Enfermagem Psiquiátrica e Ciências Humanas, Escola de Enfermagem de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Gonzaga, N.A. [Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Tirapelli, D.P.C.; Tirapelli, L.F. [Departamento de Cirurgia e Anatomia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Tirapelli, C.R. [Laboratório de Farmacologia, Departamento de Enfermagem Psiquiátrica e Ciências Humanas, Escola de Enfermagem de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2014-08-15

    The aim of the present study was to determine the mechanisms underlying the relaxant effect of adrenomedullin (AM) in rat cavernosal smooth muscle (CSM) and the expression of AM system components in this tissue. Functional assays using standard muscle bath procedures were performed in CSM isolated from male Wistar rats. Protein and mRNA levels of pre-pro-AM, calcitonin receptor-like receptor (CRLR), and Subtypes 1, 2 and 3 of the receptor activity-modifying protein (RAMP) family were assessed by Western immunoblotting and quantitative real-time polymerase chain reaction, respectively. Nitrate and 6-keto-prostaglandin F{sub 1α} (6-keto-PGF{sub 1α}; a stable product of prostacyclin) levels were determined using commercially available kits. Protein and mRNA of AM, CRLR, and RAMP 1, -2, and -3 were detected in rat CSM. Immunohistochemical assays demonstrated that AM and CRLR were expressed in rat CSM. AM relaxed CSM strips in a concentration-dependent manner. AM{sub 22-52}, a selective antagonist for AM receptors, reduced the relaxation induced by AM. Conversely, CGRP{sub 8-37}, a selective antagonist for calcitonin gene-related peptide receptors, did not affect AM-induced relaxation. Preincubation of CSM strips with N{sup G}-nitro-L-arginine-methyl-ester (L-NAME, nitric oxide synthase inhibitor), 1H-(1,2,4)oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, quanylyl cyclase inhibitor), Rp-8-Br-PET-cGMPS (cGMP-dependent protein kinase inhibitor), SC560 [5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethyl pyrazole, selective cyclooxygenase-1 inhibitor], and 4-aminopyridine (voltage-dependent K{sup +} channel blocker) reduced AM-induced relaxation. On the other hand, 7-nitroindazole (selective neuronal nitric oxide synthase inhibitor), wortmannin (phosphatidylinositol 3-kinase inhibitor), H89 (protein kinase A inhibitor), SQ22536 [9-(tetrahydro-2-furanyl)-9H-purin-6-amine, adenylate cyclase inhibitor], glibenclamide (selective blocker of ATP-sensitive K{sup +} channels), and

  13. Relaxation of soman-induced contracture of airway smooth muscle in vitro. (Reannouncement with new availability information)

    Energy Technology Data Exchange (ETDEWEB)

    Filbert, M.G.; Moore, D.H.; Adler, M.

    1992-12-31

    A possible role for beta-adrenergic agonists in the management of bronchoconstriction resulting from exposure to anticholinesterase compounds was investigated in vitro in canine tracheal smooth muscle. Norepinephrine, salbutamol and isoproterenol produced partial relaxation of soman-induced contractures. However, the relaxation induced was not sustained; muscle tensions returned to pretreatment levels within minutes despite the continued presence of beta-agonists. Increasing cAMP levels with the non beta-agonist bronchodilators such as thoophylline, a phosphodiesterase inhibitor, or forskolin, a specific stimulator of adenylate cyclase, resulted in more complete and longer lasting relaxation, suggesting that beta-adrenoceptor desensitization may contribute to the failure by beta-agonists to produce sustained relaxation. Nerve agents, Soman, Toxicity, Airway smooth muscle, In vitro, Physiology, Effects.

  14. Synthesis of the muscle relaxant [14C]L-637,510

    International Nuclear Information System (INIS)

    O'Connor, S.P.; Ellsworth, R.L.; Gatto, G.

    1991-01-01

    The synthesis of (E)-3-(9-chloro-5,6-dihydro-11H-pyrolo(2,1-b)(3)-benzazepin-11-ylidene)-N,N-dimethyl-1- [3- 14 C]-propanamine (Z)-2-butenedioate(1:1) ([ 14 C]L-637,510), a potential muscle relaxant product for which 14 C-labeling was required for metabolism studies, is described. Introduction of the label in the 3-position of the propanamine side chain was accomplished in eight steps from sodium [ 14 C]cyanide with an overall radiochemical yield of 4.8%. (author)

  15. Relaxation effect of marmin on guinea pig tracheal smooth muscle via NO-independent mechanisms

    Directory of Open Access Journals (Sweden)

    Dadang Irfan Husori

    2012-05-01

    Full Text Available Objective: To investigate the relaxation mechanims of marmin on epithelium of guinea pig isolated trachea smooth muscle (TSM. Methods: The study was conducted using in vitro isolated-trachea experimental. The guinea pig isolated trachea were incubated in Krebs solution-containing organ bath and supplied with a mixed gas of O2:CO2 (95%:5%. Result: Removal of tracheal epithelium was associated with significant increases in the potencies of histamine and methacholine to contract guinea pig TSM. The pD2 value of histamine increased from 6.04依0.08 on epithelial-intact to 6.32依0.06 on epithelial-denuded (P<0.05. The pD2 value of methacholine also increased from 5.85依0.09 on epithelial-intact to 6.15依0.07 on epithelial-denuded (P<0.05. Marmin exhibited relaxation effects on TSM induced by methacholine (3伊10-5 mol/L and histamine (3伊10-5 mol/L. Inhibition of prostaglandin E2 (PGE2 through incubation with indomethacin could reduce the relaxation effect of marmin (P<0.05 on methacholine- and histamine-induced contractions. However, no significant differenceswere shown in methylene blue, Nω-nitro-L-arginine (L-NNA and propranolol-incubated TSM. Conclusions: The results suggest that marmin has relaxation effect on TSM which is epithelial-dependent through the release of PGE2. However, nitric oxide, cGMP and 毬 2-adrenergic-mediated relaxation were not involved.

  16. Effects of Ginger and Its Constituents on Airway Smooth Muscle Relaxation and Calcium Regulation

    Science.gov (United States)

    Siviski, Matthew E.; Zhang, Yi; Xu, Carrie; Hoonjan, Bhupinder; Emala, Charles W.

    2013-01-01

    The prevalence of asthma has increased in recent years, and is characterized by airway hyperresponsiveness and inflammation. Many patients report using alternative therapies to self-treat asthma symptoms as adjuncts to short-acting and long-acting β-agonists and inhaled corticosteroids (ICS). As many as 40% of patients with asthma use herbal therapies to manage asthma symptoms, often without proven efficacy or known mechanisms of action. Therefore, investigations of both the therapeutic and possible detrimental effects of isolated components of herbal treatments on the airway are important. We hypothesized that ginger and its active components induce bronchodilation by modulating intracellular calcium ([Ca2+]i) in airway smooth muscle (ASM). In isolated human ASM, ginger caused significant and rapid relaxation. Four purified constituents of ginger were subsequently tested for ASM relaxant properties in both guinea pig and human tracheas: [6]-gingerol, [8]-gingerol, and [6]-shogaol induced rapid relaxation of precontracted ASM (100–300 μM), whereas [10]-gingerol failed to induce relaxation. In human ASM cells, exposure to [6]-gingerol, [8]-gingerol, and [6]-shogaol, but not [10]-gingerol (100 μM), blunted subsequent Ca2+ responses to bradykinin (10 μM) and S-(−)-Bay K 8644 (10 μM). In A/J mice, the nebulization of [8]-gingerol (100 μM), 15 minutes before methacholine challenge, significantly attenuated airway resistance, compared with vehicle. Taken together, these novel data show that ginger and its isolated active components, [6]-gingerol, [8]-gingerol, and [6]-shogaol, relax ASM, and [8]-gingerol attenuates airway hyperresponsiveness, in part by altering [Ca2+]i regulation. These purified compounds may provide a therapeutic option alone or in combination with accepted therapeutics, including β2-agonists, in airway diseases such as asthma. PMID:23065130

  17. The effects of music relaxation and muscle relaxation techniques on sleep quality and emotional measures among individuals with posttraumatic stress disorder

    Directory of Open Access Journals (Sweden)

    Iris Haimov

    2012-07-01

    Full Text Available Posttraumatic stress disorder (PTSD, an anxiety disorder with lifetime prevalence of 7.8%, is characterized by symptoms that develop following exposure to traumatic life events and that cause an immediate experience of intense fear, helplessness or horror. PTSD is marked by recurrent nightmares typified by the recall of intrusive experiences and by extended disturbance throughout sleep. Individuals with PTSD respond poorly to drug treatments for insomnia. The disadvantages of drug treatment for insomnia underline the importance of non-pharmacological alternatives. Thus, the present study had three aims: first, to compare the efficiency of two relaxation techniques (muscular relaxation and progressive music relaxation in alleviating insomnia among individuals with PTSD using both objective and subjective measures of sleep quality; second, to examine whether these two techniques have different effects on psychological indicators of PTSD, such as depression and anxiety; and finally, to examine how initial PTSD symptom severity and baseline emotional measures are related to the efficiency of these two relaxation methods. Thirteen PTSD patients with no other major psychiatric or neurological disorders participated in the study. The study comprised one seven-day running-in, no-treatment period, followed by two seven-day experimental periods. The treatments constituted either music relaxation or muscle relaxation techniques at desired bedtime. These treatments were randomly assigned. During each of these three experimental periods, subjects’ sleep was continuously monitored with a wrist actigraph (Ambulatory Monitoring, Inc., and subjects were asked to fill out several questionnaires concerned with a wide spectrum of issues, such as sleep, depression, and anxiety. Analyses revealed a significant increase in objective and subjective sleep efficiency and a significant reduction in depression level following music relaxation. Moreover, following music

  18. [The effect of EMG level by EMG biofeedback with progressive muscle relaxation training on tension headache].

    Science.gov (United States)

    Ro, U J; Kim, N C; Kim, H S

    1990-08-01

    The purpose of this study is to assess if EMG biofeedback training with progressive muscle relaxation training is effective in reducing the EMG level in patients with tension headaches. This study which lasted from 23 October to 30 December 1989, was conducted on 10 females who were diagnosed as patients with tension headaches and selected from among volunteers at C. University in Seoul. The process of the study was as follows: First, before the treatment, the baseline was measured for two weeks and the level of EMG was measured five times in five minutes. And then EMG biofeedback training was used for six weeks, 12 sessions in all, and progressive muscle relaxation was done at home by audio tape over eight weeks. Each session was composed of a 5-minute baseline, two 5-minute EMG biofeedback training periods and a 5-minute self-control stage. Each stage was followed by a five minute rest period. So each session took a total of 40 minutes. The EMG level was measured by EMG biofeedback (Autogenic-Cyborg: M 130 EMG module). The results were as follows: 1. The average age of the subjects was 44.1 years and the average history of headache was 10.6 years (range: 6 months-20 years). 2. The level of EMG was lowest between the third and the fourth week of the training except in Cases I and IV. 3. The patients began to show a nonconciliatory attitude at the first session of the fifth week of the training.

  19. Oral Mucosal Injection of a Local Anesthetic Solution Containing Epinephrine Enhances Muscle Relaxant Effects of Rocuronium

    Science.gov (United States)

    Ninomiya, Asako; Terakawa, Yui; Matsuura, Nobuyuki; Ichinohe, Tatsuya; Kaneko, Yuzuru

    2012-01-01

    The purpose of this study was to examine how submucosal injection of a clinically relevant dose of a lidocaine hydrochloride solution containing epinephrine affects the muscle relaxant effects of rocuronium bromide. Sixteen patients scheduled for orthognathic surgery participated in this study. All patients were induced with fentanyl citrate, a target-controlled infusion of propofol and rocuronium bromide. Anesthesia was maintained by total intravenous anesthesia. After nasotracheal intubation, an infusion of rocuronium bromide was started at 7 µg/kg/min, and the infusion rate was then adjusted to maintain a train of four (TOF) ratio at 10 to 15%. The TOF ratio just prior to oral mucosal injection of a 1% lidocaine hydrochloride solution containing 10 µg/mL epinephrine (LE) was taken as the baseline. TOF ratio was observed for 20 minutes, with 1-minute intervals following the start of injection. Mean epinephrine dose was 85.6 ± 18.6 µg and mean infusion rate of rocuronium bromide was 6.3 ± 1.6 µg/kg/min. TOF ratio began to decrease 2 minutes after the injection of LE, reached the minimum value at 3.1 ± 3.6% 12 minutes after the injection, and then began to recover. We conclude that oral mucosal injection of LE enhances the muscle relaxant effects of rocuronium bromide. PMID:22428970

  20. [Electroencephalographic effects of chlorphenesin carbamate, a new central muscle relaxant, in rabbits (author's transl)].

    Science.gov (United States)

    Watanabe, S; Araki, H; Kawasaki, H; Ueki, S

    1977-05-01

    Electroencephalographic (EEG) effects of chlorphenesin carbamate were investigated in rabbits with chronic electrode implants, and compared with those of chlormezanone and methocarbamol. Chlorphenesin carbamate (50 mg/kg i.v., 100 mg/kg i.d.) induced a drowsy pattern of spontaneous EEG consisting of high voltage slow waves in the cortex and amygdala, and desynchronization of hippocampal theta waves. Chlormezanone also elicited similar EEG changes but such were much more potent than chlorphenesin carbamate. Methocarbamol showed no effect on spontaneous EEG. Chlorphenesin carbamate caused sedation in this period and muscle relaxation was more potent than that of chlormezanone. The EEG arousal response to auditory stimulation and to electric stimulation of the posterior hypothalamus, centromedian thalamus and mesencephalic reticular formation was slightly depressed by chlorphenesin carbamate. Chlorphenesin carbamate, as with chlormezanone, markedly depressed the limbic afterdischarges elicited by hippocampal stimulation. These EEG effects of chlorphenesin carbamate were qualitatively similar to but much weaker than those of chlormezanone, whereas the muscle relaxant effect of chlorphenesin carbamate was more potent than that of chlormezanone.

  1. Comparative efficacy of Combination of Propofol or Thiopental with Remifentanil on Tracheal Intubation without Muscle Relaxants

    Directory of Open Access Journals (Sweden)

    k Naseri

    2007-10-01

    Full Text Available Introduction & Objective: In some medical situations administration of muscle relaxants after intravenous anesthetics for tracheal intubation may be unnecessary or sometimes could be hazardous. In such situations, replacing an alternative drug for the facilitation of tracheal intubation is obvious. Remifentanil is a short acting opioid drug which may be useful in solving this problem. The aim of this study was to compare the effects of propofol or thiopental in combination with remifentanil in the absence of muscle relaxants on larengoscopy and intubation conditions in general anesthesia. Materials & Methods: This is a randomized double-blind clinical trial which was performed in 1386 in Be’sat hospital of Sanandaj. Forty two ASA 1 and 2 patients recruited to receive propofol, 2 Mg/Kg, or thiopental, 5Mg/K. All patients received lidocaine, 1.5 Mg/Kg, and remifentanil, 2.5 µg/Kg, 30 seconds before anesthetics administration. larengoscopy and tracheal intubation were done 90 seconds after induction of anesthesia. On the basis of mask ventilation, jaw relaxation, vocal cords position and patient's response to intubations and endotracheal tube cuff inflation the intubation conditions were assessed and recorded as excellent, good ,acceptable or poor. The mean arterial pressure and heart rate were measured before and after anesthetics administration and also 45 seconds and two and five minutes after intubations. Data were analyzed by X2, fisher exact test ant student T-test using SPSS software. Results: Excellent or good larengoscopy and intubation conditions were observed in 9 (%42.9 of thiopental patients and 20 (%95.2 of propofol patients (p<0.05. Mean arterial pressure and heart rate decreased more significantly in propofol group in comparison with the thiopental group (p<0.05. Conclusion: Combination of remifentanil and propofol or thiopental could facilitate ventilation via face mask in all patients. Although combination of propofol and

  2. Myosin dephosphorylation during rapid relaxation of hog carotid artery smooth muscle.

    Science.gov (United States)

    Driska, S P; Stein, P G; Porter, R

    1989-02-01

    Changes in myosin light chain phosphorylation were measured during histamine-induced rhythmic contractions of hog carotid artery smooth muscle strips. Histamine made the muscle strips contract spontaneously every 1-5 min, and this allowed measurement of the time course of phosphorylation in relation to force development under conditions where diffusion of the agonist through tissue would not complicate the interpretation of the data. In the absence of histamine, phosphorylation was low [0.12 +/- 0.04 mol P/mol of the 20,000-Da light chain (LC 20)]. Phosphorylation was slightly (but not significantly) higher in the presence of 10 microM histamine in the relaxed state between contractions (0.20 +/- 0.03 mol P/mol LC 20). In muscle strips frozen during force development, when force had reached half of its peak value, phosphorylation was 0.38 +/- 0.06 mol P/mol LC 20. The highest levels of phosphorylation (0.49 +/- 0.04 mol P/mol LC 20) were found in strips frozen at the peak of the rhythmic contractions. Strips frozen when force had declined to half of the peak force showed low levels of phosphorylation (0.17 +/- 0.07 mol P/mol LC 20), indicating that the myosin light chain phosphatase activity was quite high. Mathematical modeling of the kinase and phosphatase reactions suggested that the apparent first-order phosphatase rate constant was at least 0.08 s-1 under these conditions. To obtain a better estimate of this rate constant, a second series of phosphorylation measurements were made early in the relaxation phase of the rhythmic contractions. The highest phosphatase rate constant obtained from these measurements was 0.23 s-1.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Crosstalk between Gi and Gq/Gs pathways in airway smooth muscle regulates bronchial contractility and relaxation

    OpenAIRE

    McGraw, Dennis W.; Elwing, Jean M.; Fogel, Kevin M.; Wang, Wayne C.H.; Glinka, Clare B.; Mihlbachler, Kathryn A.; Rothenberg, Marc E.; Liggett, Stephen B.

    2007-01-01

    Receptor-mediated airway smooth muscle (ASM) contraction via Gαq, and relaxation via Gαs, underlie the bronchospastic features of asthma and its treatment. Asthma models show increased ASM Gαi expression, considered the basis for the proasthmatic phenotypes of enhanced bronchial hyperreactivity to contraction mediated by M3-muscarinic receptors and diminished relaxation mediated by β2-adrenergic receptors (β2ARs). A causal effect between Gi expression and phenotype has not been established, n...

  4. Myosin Va Plays a Role in Nitrergic Smooth Muscle Relaxation in Gastric Fundus and Corpora Cavernosa of Penis

    Science.gov (United States)

    Carew, Josephine A.; Goyal, Raj K.; Sullivan, Maryrose P.

    2014-01-01

    The intracellular motor protein myosin Va is involved in nitrergic neurotransmission possibly by trafficking of neuronal nitric oxide synthase (nNOS) within the nerve terminals. In this study, we examined the role of myosin Va in the stomach and penis, proto-typical smooth muscle organs in which nitric oxide (NO) mediated relaxation is critical for function. We used confocal microscopy and co-immunoprecipitation of tissue from the gastric fundus (GF) and penile corpus cavernosum (CCP) to localize myosin Va with nNOS and demonstrate their molecular interaction. We utilized in vitro mechanical studies to test whether smooth muscle relaxations during nitrergic neuromuscular neurotransmission is altered in DBA (dilute, brown, non-agouti) mice which lack functional myosin Va. Myosin Va was localized in nNOS-positive nerve terminals and was co-immunoprecipitated with nNOS in both GF and CCP. In comparison to C57BL/6J wild type (WT) mice, electrical field stimulation (EFS) of precontracted smooth muscles of GF and CCP from DBA animals showed significant impairment of nitrergic relaxation. An NO donor, Sodium nitroprusside (SNP), caused comparable levels of relaxation in smooth muscles of WT and DBA mice. These normal postjunctional responses to SNP in DBA tissues suggest that impairment of smooth muscle relaxation resulted from inhibition of NO synthesis in prejunctional nerve terminals. Our results suggest that normal physiological processes of relaxation of gastric and cavernosal smooth muscles that facilitate food accommodation and penile erection, respectively, may be disrupted under conditions of myosin Va deficiency, resulting in complications like gastroparesis and erectile dysfunction. PMID:24516539

  5. Cutaneous Sensory Block Area, Muscle-Relaxing Effect, and Block Duration of the Transversus Abdominis Plane Block

    DEFF Research Database (Denmark)

    Støving, Kion; Rothe, Christian; Rosenstock, Charlotte V

    2015-01-01

    BACKGROUND AND OBJECTIVES: The transversus abdominis plane (TAP) block is a widely used nerve block. However, basic block characteristics are poorly described. The purpose of this study was to assess the cutaneous sensory block area, muscle-relaxing effect, and block duration. METHODS: Sixteen...... healthy volunteers were randomized to receive an ultrasound-guided unilateral TAP block with 20 mL 7.5 mg/mL ropivacaine and placebo on the contralateral side. Measurements were performed at baseline and 90 minutes after performing the block. Cutaneous sensory block area was mapped and separated...... into a medial and lateral part by a vertical line through the anterior superior iliac spine. We measured muscle thickness of the 3 lateral abdominal muscle layers with ultrasound in the relaxed state and during maximal voluntary muscle contraction. The volunteers reported the duration of the sensory block...

  6. Streptozotocin diabetes attenuates the effects of nondepolarizing neuromuscular relaxants on rat muscles.

    Science.gov (United States)

    Huang, Lina; Chen, Dan; Li, Shitong

    2014-12-01

    The hypothesis of this study was that diabetes-induced desensitization of rat soleus (SOL) and extensor digitorum longus (EDL) to non-depolarizing muscle relaxants (NDMRs) depends on the stage of diabetes and on the kind of NDMRs. We tested the different magnitude of resistance to vecuronium, cisatracurium, and rocuronium at different stages of streptozotocin (STZ)-induced diabetes by the EDL sciatic nerve-muscle preparations, and the SOL sciatic nerve-muscle preparations from rats after 4 and 16 weeks of STZ treatment. The concentration-twitch tension curves were significantly shifted from those of the control group to the right in the diabetic groups. Concentration giving 50% of maximal inhibition (IC50) was larger in the diabetic groups for all the NDMRs. For rocuronium and cisatracurium in both SOL and EDL, IC50 was significantly larger in diabetic 16 weeks group than those in the diabetic 4 weeks group. For SOL/EDL, the IC50 ratios were significantly largest in the diabetic 16 weeks group, second largest in the diabetic 4 weeks group, and smallest for the control group. Diabetes-induced desensitization to NDMRs depended on the stage of diabetes and on the different kind of muscles observed while was independent on different kind of NDMRs. The resistance to NDMRs was stronger in the later stage of diabetes (16 versus 4 weeks after STZ treatment). Additionally, when monitoring in SOL, diabetes attenuated the actions of neuromuscular blockade more intensely than that in EDL. Nonetheless, the hyposensitivity to NDMRs in diabetes was not relevant for the kind of NDMRs.

  7. Effectiveness of passive stretching versus hold relax technique in flexibility of hamstring muscle

    Directory of Open Access Journals (Sweden)

    Gauri Shankar

    2010-10-01

    Full Text Available Aim: To compare the effectiveness of passive stretching and hold relax technique in the flexibility of hamstring muscle. Methods: A total of 80 normal healthy female subjects between age group 20-30 years referred to the department of physiotherapy, Sumandeep Vidyapeeth University, sampling method being convenient sampling. The subjects were randomly divided in two groups i.e. passive stretching group (n=40 and PNF group (n=40 and given passive stretching and proprioceptive neuromuscular facilitation technique respectively. Active knee extension range was measured before and after the intervention by goniometer. Results: t test showed a highly significant (p=0.000 increase in range of motion in PNF group. Conclusion: Proprioceptive neuromuscular facilitation technique is more effective in increasing hamstring flexibility than the passive stretching.

  8. Effects of Progressive Muscle Relaxation Counseling on Anxiety among Primigravida Women Referred to Health Care Centers in Hamadan

    Directory of Open Access Journals (Sweden)

    Fateme Shobeiri

    2015-09-01

    Full Text Available Background and Objectives: Progressive muscle relaxation is a non-invasive, cost-effective and complication less method which can be performed independently by the individual. Considering the importance of psychological problems during pregnancy, the purpose of this study was to evaluate the effect of progressive muscle relaxation counseling on anxiety among primigravida women referred to health care centers in Hamadan, Iran. Materials and Methods: This study was a randomized clinical trial with two groups (experimental and control with pre-test and post-test. A total of 120 women were referred to health centers in Hamadan who were experiencing their first pregnancy and were consecutively enrolled in the study, after obtaining informed consents. They were randomly assigned to intervention and control groups (60 women in each group by allocation concealment. The control group only received routine prenatal care, but the experimental group after two counseling sessions and learning muscle relaxation techniques performed progressive muscle relaxation exercises from 21-22 weeks for 10 weeks, and completed the daily performance sheet of relaxation. The study data collection tools included a demographic questionnaire, Spielberger state-trait anxiety inventory, and the daily performance sheet for the intervention group. Data were analyzed in SPSS 20 using independent samples t-test, Analysis of covariance (ANCOVA, and paired t-test. Results: Data analysis reflected the homogeneity of the state and trait anxiety levels in both groups before the intervention. The results showed that state and trait anxiety in the control group after the intervention was significantly increased (P<0.001, but the experimental group showed a significant decrease in state and trait anxiety after the intervention (P<0.001. Conclusions: Teaching progressive muscle relaxation techniques to pregnant women can have a significant impact on reducing pregnancy anxiety.

  9. Pharmacological identification of β-adrenoceptor subtypes mediating isoprenaline-induced relaxation of guinea pig colonic longitudinal smooth muscle.

    Science.gov (United States)

    Chino, Daisuke; Sone, Tomoyo; Yamazaki, Kumi; Tsuruoka, Yuri; Yamagishi, Risa; Shiina, Shunsuke; Obara, Keisuke; Yamaki, Fumiko; Higai, Koji; Tanaka, Yoshio

    2018-01-01

    Object We aimed to identify the β-adrenoceptor (β-AR) subtypes involved in isoprenaline-induced relaxation of guinea pig colonic longitudinal smooth muscle using pharmacological and biochemical approaches. Methods Longitudinal smooth muscle was prepared from the male guinea pig ascending colon and contracted with histamine prior to comparing the relaxant responses to three catecholamines (isoprenaline, adrenaline, and noradrenaline). The inhibitory effects of subtype-selective β-AR antagonists on isoprenaline-induced relaxation were then investigated. Results The relaxant potencies of the catecholamines were ranked as: isoprenaline > noradrenaline ≈ adrenaline, whereas the rank order was isoprenaline > noradrenaline > adrenaline in the presence of propranolol (a non-selective β-AR antagonist; 3 × 10 -7 M). Atenolol (a selective β 1 -AR antagonist; 3 × 10 -7 -10 -6  M) acted as a competitive antagonist of isoprenaline-induced relaxation, and the pA 2 value was calculated to be 6.49 (95% confidence interval: 6.34-6.83). The relaxation to isoprenaline was not affected by ICI-118,551 (a selective β 2 -AR antagonist) at 10 -9 -10 -8  M, but was competitively antagonized by 10 -7 -3 × 10 -7  M, with a pA 2 value of 7.41 (95% confidence interval: 7.18-8.02). In the presence of propranolol (3 × 10 -7 M), the relaxant effect of isoprenaline was competitively antagonized by bupranolol (a non-selective β-AR antagonist), with a pA 2 value of 5.90 (95% confidence interval: 5.73-6.35). Conclusion These findings indicated that the β-AR subtypes involved in isoprenaline-induced relaxation of colonic longitudinal guinea pig muscles are β 1 -AR and β 3 -AR.

  10. Efficacy of IV Buscopan as a muscle relaxant in CT colonography

    International Nuclear Information System (INIS)

    Bruzzi, John F.; Brennan, Darren D.; Fenlon, Helen M.; Moss, Alan C.; MacMathuna, Padraic

    2003-01-01

    The aim of this study was to examine the efficacy of IV Buscopan as a muscle relaxant in CT colonography in terms of colonic distension and polyp detection, and to determine its particular efficacy in patients with diverticular disease. Seventy-three consecutive patients were randomised to receive IV Buscopan or no muscle relaxant prior to CT colonography. CT colonography was performed using a Siemens Somatom 4-detector multislice CT scanner. The following parameters were recorded: degree of colonic distension using a 4-point scale; diagnostic adequacy of colonic distension; presence or absence of diverticular disease; and presence of colonic polyps. Accuracy of polyp detection was assessed using subsequent conventional colonoscopy as a gold standard. There was no significant difference between the two groups in the number of segments that were deemed to be optimally or adequately distended (p=0.37). Although IV Buscopan did improve distension of certain segments, this effect was not sufficient to improve the number of diagnostically adequate studies in the Buscopan group (p=0.14). In patients with diverticular disease, IV Buscopan did not have any significant effect on segments affected by diverticulosis but was associated with an improvement in distension of more proximal segments. There was no significant difference between the two groups in terms of polyp detection (p=0.34). The addition of prone scanning to supine scanning was found to be the most useful technique for maximising colonic distension. Intravenous Buscopan at CT colonography does not improve the overall adequacy of colonic distension nor the accuracy of polyp detection. In patients with sigmoid diverticular disease IV Buscopan improves distension of more proximal colonic segments and may be useful in selected cases, but our results do not support its routine use for CT colonography. (orig.)

  11. Time course of action and endotracheal intubating conditions of Org 9487, a new short-acting steroidal muscle relaxant; a comparison with succinylcholine

    NARCIS (Netherlands)

    Wierda, JMKH; van den Broek, L; Proost, JH; Verbaan, BW; Hennis, PJ

    In a randomized study, we evaluated lag time (time from the end of injection of muscle relaxant until the first depression of the train-of-four response [TOF]), onset time (time from the end of injection of muscle relaxant until the maximum depression of the first twitch of the TOF [T1]),

  12. Muscle relaxants for nonspecific low back pain: a systematic review within the framework of the cochrane collaboration

    NARCIS (Netherlands)

    van Tulder, M W; Touray, T; Furlan, A D; Solway, S; Bouter, L M

    STUDY DESIGN: A systematic review of randomized and/or double-blinded controlled trials. SUMMARY OF BACKGROUND DATA: The use of muscle relaxants in the management of nonspecific low back pain is controversial. It is not clear if they are effective, and concerns have been raised about the potential

  13. Temperature effect on the rates of isometric force development and relaxation in the fresh and fatigued human adductor pollicis muscle

    NARCIS (Netherlands)

    de Ruiter, C J; Jones, D A; Sargeant, A J; de Haan, A

    1999-01-01

    The purpose of the present study was to investigate the effect of temperature on the rates of isometric force development and relaxation in electrically activated fresh and fatigued human adductor pollicis muscle. Following immersion of the lower arm for 20 min in water baths of four different

  14. Application of magnetic liposomes for magnetically guided transport of muscle relaxants and anti-cancer photodynamic drugs

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, Anatoly A.; Filippov, Victor I.; Alyautdin, Renat N.; Torshina, N.L.; Kuznetsov, O.A. E-mail: oleg@louisiana.edu

    2001-07-01

    Magnetic liposomes containing submicron-sized ferromagnetic particles were prepared encapsulating the muscle relaxant drugs, diadony or diperony, for local anesthesia. Alternatively, metal phthalocyanines (Photosense or Teraphthal), sensitizers for photodynamic or catalytic cancer therapy were loaded into the magnetic liposomes. Animal trials demonstrated successful magnetically guided transport of the drug-loaded liposomes.

  15. Application of magnetic liposomes for magnetically guided transport of muscle relaxants and anti-cancer photodynamic drugs

    International Nuclear Information System (INIS)

    Kuznetsov, Anatoly A.; Filippov, Victor I.; Alyautdin, Renat N.; Torshina, N.L.; Kuznetsov, O.A.

    2001-01-01

    Magnetic liposomes containing submicron-sized ferromagnetic particles were prepared encapsulating the muscle relaxant drugs, diadony or diperony, for local anesthesia. Alternatively, metal phthalocyanines (Photosense or Teraphthal), sensitizers for photodynamic or catalytic cancer therapy were loaded into the magnetic liposomes. Animal trials demonstrated successful magnetically guided transport of the drug-loaded liposomes

  16. A temporary decrease in twitch response during reversal of rocuronium-induced muscle relaxation with a small dose of sugammadex

    NARCIS (Netherlands)

    Eleveld, Douglas J.; Kuizenga, Karel; Proost, Johannes H.; Wierda, J. Mark K. H.

    BACKGROUND: We present a case in which a temporary decrease in train-of-four (TOF) response was observed after reversal of muscle relaxation with a small dose (0.5 mg/kg) of sugammadex administered 42 min after 0.9 mg/kg of rocuronium. At the end of the operation, the TOF ratio was > 0.9, and the

  17. Intravenous regional anesthesia: a review of common local anesthetic options and the use of opioids and muscle relaxants as adjuncts

    Directory of Open Access Journals (Sweden)

    Flamer D

    2011-11-01

    Full Text Available David Flamer, Philip WH PengDepartment of Anesthesia, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, ON, CanadaPurpose: To provide a review of local anesthetic (LA agents and adjuncts, opioids and muscle relaxants, and their intraoperative effects and postoperative outcomes in intravenous regional anesthesia (IVRA.Source: A search for prospective, double-blind, randomized controlled trials evaluating LA agents, opioids and muscle relaxants as adjuvants for IVRA, was conducted (MEDLINE®, Embase. Intraoperative benefits (onset/recovery of sensory and motor block, intraoperative analgesia, tourniquet pain, postoperative benefits (pain score, analgesic consumption, time to first analgesia, and side effects were recorded. A conclusion for overall benefit was made based on statistical significance and clinical relevance.Findings: Thirty-one studies were evaluated, with data collected on 1523 subjects. LA agents evaluated were lidocaine, ropivacaine, and prilocaine. Adjuncts evaluated were opioids (morphine, fentanyl, meperidine, sufentanil, tramadol and muscle relaxants (pancuronium, atracurium, mivacurium, cisatacurium. There was good evidence that ropivacaine provided effective IVRA and improved postoperative analgesia. Lidocaine and prilocaine were effective LA agents, however they lacked postoperative benefits. Morphine, fentanyl, and meperidine as sole adjuncts did not demonstrate clinically significant benefits or result in an increased risk of side effects. Sufentanil data was limited, but appeared to provide faster onset of sensory block. Tramadol provided faster onset of sensory block and tourniquet tolerance, however postoperative benefits were not consistent and the risk of minor side effects increased. Muscle relaxants improved the quality of motor block, but at the expense of delayed motor recovery. The combination of fentanyl and muscle relaxants can achieve an equivalent quality of IVRA with 50

  18. Relaxant effect of ghrelin on guinea pig isolated tracheal smooth muscle: role of epithelial NO and PGE2.

    Science.gov (United States)

    Al-Ayed, Mohammed Saeed Zayed

    2018-06-01

    This study aimed at investigating the potential ghrelin relaxing effect on guinea pig isolated tracheal smooth muscle (TSM). Using an in vitro experimental approach, the physiological role of the airway epithelium on smooth muscle relaxation has been investigated by analyzing the dose-response curves for carbachol- or histamine-induced contractions on epithelium intact versus denuded tracheal tissue. The relaxant effect of ghrelin (5-200 μmol/L) then investigated on carbachol-contracted, non-sensitized, and ovalbumin (OVA)-sensitized guinea pig TSM with an intact or denuded epithelium. The isolated TSMs from identical guinea pigs were incubated in Krebs solution aerated with 95% O 2 and 5% CO 2 through an automated tissue organ bath system (n = 6 for each group). The ghrelin relaxation mechanism was assessed by adding L-NAME, indomethacin, and YIL-781 for GHS-R1 into the tissue chamber. The spasmogens carbachol and histamine have shown a significantly higher contracting effect on epithelium-denuded than in epithelium-intact TSM confirmed by the significantly higher mean pEC50 of both agonists on the epithelium-denuded trachea (p < 0.05). Ghrelin has shown a concentration-dependent relaxing effect on carbachol-contracted TSM (r = 0.96, p = 0.00). The effect was more evident in the intact non-sensitized than in epithelium-denuded or OVA-sensitized groups (p < 0.05). Preincubation with nitric oxide (NO) and prostaglandin E 2 (PGE 2 ) inhibitors has significantly reduced the ghrelin-induced relaxation on epithelium-intact TSM suggesting an epithelium-dependant mechanism. However, GHS-R1a antagonist has also succeeded to reduce ghrelin relaxant effect, which needs further clarification. Ghrelin proved to have a potential TSM relaxant effect possibly through epithelium-dependant mechanisms involving NO and PGE 2 .

  19. Nondepolarizing muscle relaxant improves direct laryngoscopy view with no effect on face mask ventilation

    Directory of Open Access Journals (Sweden)

    Marwan S. Rizk

    2017-07-01

    Full Text Available Background: Difficult or impossible face mask ventilation complicated with difficult tracheal intubation during anesthesia induction occurs in 0.4% of adult anesthesia cases, possibly leading to life-threatening complications. Because of such catastrophes, muscle relaxants have been recommended to be administered after confirming adequate face mask ventilation without a solid scientific validation of this principal. Methods: In this observational study, the ease of ventilation and the scores of direct laryngoscopy views before and after administration of cisatracurium were assessed in ninety young healthy adults, without anesthetic risks and without foreseen difficult intubation and who were scheduled for general elective surgeries. Results: Before muscle relaxation, 43 patients (48% were Cormack Grade I, while the remaining 47 patients (52% were either Cormack Grade II (28 patients, 31% or Cormack Grade II (19 patients, 21%. Following muscle relaxation with cisatracurium, the number of patients with Cormack Grade I significantly increased from 43 patients (48% to 65 patients (72% (p = 0.0013. Only 1 patient out of 19 patients (5% improved his Cormack grade from Grade III to Grade I while 16 out 19 patients (84% improved their Cormack grade from Grade III to Grade II after the use of cisatracurium. The quality of face mask ventilation did not differ with and without muscle relaxants in all patients. Conclusion: The use of cisatracurium in healthy young adults undergoing general elective surgeries with no anticipated difficult endotracheal intubation had no effect on the quality of face mask ventilation despite resulting in a quantifiable improvement in the laryngeal view. Resumo: Justificativa: A ventilação difícil ou impossível via máscara facial complicada pela intubação traqueal difícil durante a indução da anestesia ocorre em 0,4% dos casos de anestesia em adultos, possivelmente levando a complicações fatais. Devido a tais cat

  20. Duchenne muscular dystrophy carriers. Proton spin-lattice relaxation times of skeletal muscles on magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, K.; Nakano, I. (Shimoshizu National Hospital, Chiba (Japan). Dept. of Neurology); Fukuda, N.; Ikehira, H.; Tateno, Y. (National Inst. of Radiological Sciences, Chiba (Japan). Div. of Clinical Research); Aoki, Y. (National Inst. of Radiological Sciences, Chiba (Japan))

    1989-11-01

    By means of magnetic resonance imaging (MRI), the proton spin-lattice relaxation times (T1 values) of the skeletal muscles were measured in Duchenne muscular dystrophy (DMD) carriers and normal controls. The bound water fraction (BWF) was calculated from the T1 values obtained, according to the fast proton diffusion model. In the DMD carriers, T1 values of the gluteus maximus and quadriceps femoris muscles were significantly higher, and BWFs of these muscles were significantly lower than in normal control. Degenerative muscular changes accompanied by interstitial edema were presumed responsible for this abnormality. No correlation was observed between the muscle T1 and serum creatine kinase values. The present study showed that MRI could be a useful method for studying the dynamic state of water in both normal and pathological skeletal muscles. Its possible utility for DMD carrier detection was discussed briefly. (orig.).

  1. Dietary polyphenols generate nitric oxide from nitrite in the stomach and induce smooth muscle relaxation

    International Nuclear Information System (INIS)

    Rocha, Barbara S.; Gago, Bruno; Barbosa, Rui M.; Laranjinha, Joao

    2009-01-01

    Nitrite, considered a biological waste and toxic product, is being regarded as an important physiological molecule in nitric oxide (·NO) biochemistry. Because the interaction of dietary phenolic compounds and nitrite would be kinetically (due to the high concentrations achieved) and thermodynamically (on basis of the redox potentials) feasible in the stomach, we have studied the potential reduction of nitrite by polyphenols present in several dietary sources. By measuring the time courses of ·NO production in simulated gastric juice (pH 2), the efficiency of the compounds studied is as follows: Epicatechin-3-O-gallate > quercetin > procyanidin B8 dimer > oleuropein > procyanidin B2 dimer > chlorogenic acid > epicatechin > catechin > procyanidin B5 dimer. The initial rates of ·NO production fall in a narrow range (ca. 1-5 μM s -1 ) but the distinct kinetics of the decay of ·NO signals suggest that competition reactions for ·NO are operative. The proof of concept that, in the presence of nitrite, phenol-containing dietary products induce a strong increase of ·NO in the stomach was established in an in vivo experiment with healthy volunteers consuming lettuce, onions, apples, wine, tea, berries and cherries. Moreover, selected mixtures of oleuropein and catechin with low nitrite (1 μM) were shown to induce muscle relaxation of stomach strips in a structure-dependent way. Data presented here brings strong support to the concept that polyphenols consumed in a variety of dietary products, under gastric conditions, reduce nitrite to ·NO that, in turn, may exert a biological impact as a local relaxant.

  2. Identification of mechanisms involved in the relaxation of rabbit cavernous smooth muscle by a new nitric oxide donor ruthenium compound

    Directory of Open Access Journals (Sweden)

    João Batista Gadelha de Cerqueira

    2012-10-01

    Full Text Available PURPOSE: The aim of this study was to evaluate the relaxation in vitro of cavernous smooth muscle induced by a new NO donor of the complex nitrosil-ruthenium, named trans-[Ru(NH34(caffeine(NO]C13 (Rut-Caf and sodium nitroprusside (SNP. MATERIALS AND METHODS: The tissues, immersed in isolated bath systems, were pre-contracted with phenilephrine (PE (1 µM and then concentration-response curves (10-12 - 10-4 M were obtained. To clarify the mechanism of action involved, it was added to the baths ODQ (10 µM, 30 µM, oxyhemoglobin (10 µM, L-cysteine (100 µM, hydroxicobalamine (100 µM, glibenclamide, iberotoxin and apamine. Tissue samples were frozen in liquid nitrogen to measure the amount of cGMP and cAMP produced. RESULTS: The substances provoked significant relaxation of the cavernous smooth muscle. Both Rut-Caf and SNP determined dose-dependent relaxation with similar potency (pEC50 and maximum effect (Emax. The substances showed activity through activation of the soluble guanylyl cyclase (sGC, because the relaxations were inhibited by ODQ. Oxyhemoglobin significantly diminished the relaxation effect of the substances. L-cysteine failed to modify the relaxations caused by the agents. Hydroxicobalamine significantly diminished the relaxation effect of Rut-Caf. Glibenclamide significantly increased the efficacy of Rut-Caf (pEC50 4.09 x 7.09. There were no alterations of potency or maximum effect of the substances with the addition of the other ion channel blockers. Rut-Caf induced production of significant amounts of cGMP and cAMP during the relaxation process. CONCLUSIONS: In conclusion, Rut-Caf causes relaxation of smooth muscle of corpus cavernosum by means of activation of sGC with intracellular production of cGMP and cAMP; and also by release of NO in the intracellular environment. Rut-Caf releases the NO free radical and it does not act directly on the potassium ion channels.

  3. Effect of a muscle relaxant, chlorphenesin carbamate, on the spinal neurons of rats.

    Science.gov (United States)

    Kurachi, M; Aihara, H

    1984-09-01

    The effects of chlorphenesin carbamate (CPC) and mephenesin on spinal neurons were investigated in spinal rats. CPC (50 mg/kg i.v.) inhibited the mono-(MSR) and poly-synaptic reflex (PSR), the latter being more susceptible than the former to CPC depression. Mephenesin also inhibited MSR and PSR, though the effects were short in duration. CPC had no effect on the dorsal root potential evoked by the stimulation of the dorsal root, while mephenesin reduced the dorsal root-dorsal root reflex. The excitability of motoneuron was reduced by the administration of CPC or mephenesin. The excitability of primary afferent terminal was unchanged by CPC, while it was inhibited by mephenesin. Neither CPC nor mephenesin influenced the field potential evoked by the dorsal root stimulation. Both CPC and mephenesin had no effect on the synaptic recovery. These results suggest that both CPC and mephenesin inhibit the firing of motoneurons by stabilizing the neuronal membrane, while mephenesin additionally suppresses the dorsal root reflex and the excitability of the primary afferent terminal. These inhibitory actions of CPC on spinal activities may contribute, at least partly, to its muscle relaxing action.

  4. The Pringle maneuver reduces the infusion rate of rocuronium required to maintain surgical muscle relaxation during hepatectomy.

    Science.gov (United States)

    Kajiura, Akira; Nagata, Osamu; Sanui, Masamitsu

    2018-04-27

    We investigated the continuous infusion rates of rocuronium necessary to obtain the surgical muscle relaxation before, during, and after the Pringle maneuver on patients who underwent hepatectomy. Fifteen patients were induced by total intravenous anesthesia with propofol. After obtaining the calibration of acceleromyography, the patient was intubated with rocuronium 0.6 mg/kg. Fifteen minutes after initial rocuronium injection, the continuous infusion was started at 7.5 µg/kg/min. The infusion rate was adjusted every 15 min so that the first twitch height (% T1) might become from 3 to 10% of control. The infusion rates at the time when the state of surgical muscle relaxation was achieved for more than 15 min were recorded before, during and after the Pringle maneuver. The 25% recovery time was measured after discontinuing the continuous infusion. The infusion rate of rocuronium before, during, and after the Pringle maneuver was 7.2 ± 1.8, 4.2 ± 1.4, and 4.7 ± 1.5 µg/kg/min (mean ± SD), respectively. The rocuronium infusion rate during the Pringle maneuver was decreased about 40% compared to that before this maneuver, and that after completion of the Pringle maneuver was not recovered to that before the Pringle maneuver. The 25% recovery time was 20 ± 7 min. In case of continuous administration of rocuronium during surgery performing the Pringle maneuver, it was considered necessary to regulate the administration of rocuronium using muscle relaxant monitoring in order to deal with the decrease in muscle relaxant requirement by the Pringle maneuver.

  5. Breathing and Relaxation

    Science.gov (United States)

    ... Find a Doctor Relaxation is the absence of tension in muscle groups and a minimum or absence ... Drill Meditation Progressive Muscle Relaxation Minimizing Shortness of Breath Visualization This information has been approved by Shelby ...

  6. [Inductions and intubating conditions with sevoflurane and different doses of remifentanil without muscle relaxant in children].

    Science.gov (United States)

    Wei, Ling-Xin; Deng, Xiao-Ming; Liu, Ju-Hui; Luo, Mao-Ping; Tong, Shi-Yi; Zhang, Yan-Ming; Liao, Xu; Xu, Kun-Lin

    2008-12-01

    To observe the clinical effectiveness of inductions and tracheal intubating conditions with 3% sevoflurane and different doses of remifentanil without muscle relaxant in children. Totally 120 peadiatric patients (aged 4-10 years, American Society of Anesthesiologists grade I for inhalational induction) were randomly allocated into group I (remifentanil 1 microg/kg), group II (remifentanil 2 microg/kg), group III (remifentanil 3 microg/kg), and control group (vecuronium bromide 0.1 mg/kg). After inhalational induction with 3% sevoflurane and 60% nitrous oxide in 40% oxygen for 2 minutes, remifentanil 1 microg/kg, 2 microg/ kg, and 3 microg/kg were intravenously injected over 1 minute into patients in group I , group II, and group III, respectively. After remifentanil administration and manual ventilation for 1 minute, the trachea was intubated. In the control group, 2 minutes after intravenous administration of vecuronium bromide 0.1 mg/kg, tracheal intubation was attempted. Agitation, intubating satisfactoriness, and the circulation changes after tracheal intubation and anesthesia induction were observed. In these four groups, agitation occurred in 37.5% of patients during sevoflurane induction. Satisfactory intubation rate was 70.0% in group I, 86.7% in group II, 90.0% in group III, and 93.3% in the control group. Compared with the control group, the impact of tracheal intubation on the circulatory system was smaller in group I , II , and III. Induction with 3% sevoflurane combined with remifentanil can be smoothly performed, followed by the successful tracheal intubation. The intubating conditions are more satisfactory with 3% sevoflurane combined with remifentanil 2 microg/kg or 3 microg/kg.

  7. Treatment of Storm Fears Using Virtual Reality and Progressive Muscle Relaxation.

    Science.gov (United States)

    Lima, Jessica; McCabe-Bennett, Hanna; Antony, Martin M

    2018-03-01

    The present study examined the efficacy of virtual reality (VR) exposure therapy for treating individuals with storm fears by comparing a one-session VR exposure treatment with a one-session progressive muscle relaxation (PMR) and psychoeducation session. It was predicted that there would be a reduction in storm-related fear post-treatment for individuals in both conditions, but that this reduction would be greater for those in the VR exposure condition. It was predicted that improvements would be maintained at 30-day follow-up only for those in the VR exposure condition. Thirty-six participants each received one of the two treatment conditions. Those in the PMR treatment group received approximately 30 minutes of PMR and approximately 15 minutes of psychoeducation regarding storms. Those in the VR treatment group received approximately 1 hour of VR exposure. Additionally, participants were asked to complete a pre-treatment and post-treatment 5-minute behavioural approach test to assess changes in storm fears. They were also asked to complete a measure assessing storm phobia. There was a significant interaction between treatment group and self-reported fear at post-treatment, such that fear decreased for both groups, although the reduction was stronger in the VR group. Results also showed that reductions in storm fear were maintained at 30-day follow-up for both groups. Although this study used a small non-clinical sample, these results offer preliminary support for the use of VR exposure therapy in the treatment of storm-related fear.

  8. Rocuronium Versus Suxamethonium: A Survey of First-line Muscle Relaxant Use in UK Prehospital Rapid Sequence Induction.

    Science.gov (United States)

    Hartley, Emma L; Alcock, Roger

    2015-04-01

    Prehospital anaesthesia in the United Kingdom (UK) is provided by Helicopter Emergency Medical Service (HEMS) and British Association for Immediate Care (BASICS), a road-based service. Muscle relaxation in rapid sequence induction (RSI) has been traditionally undertaken with the use of suxamethonium; however, rocuronium at higher doses has comparable intubating conditions with fewer side effects. The aim of this survey was to establish how many prehospital services in the UK are now using rocuronium as first line in RSI. An online survey was constructed identifying choice of first-line muscle relaxant for RSI and emailed to lead clinicians for BASICS and HEMS services across the UK. If rocuronium was used, further questions regarding optimal dose, sugammadex, contraindications, and difference in intubating conditions were asked. A total of 29 full responses (93.5%) were obtained from 31 services contacted. Suxamethonium was used first line by 17 prehospital services (58.6%) and rocuronium by 12 (41.4%). In 11 services (91.7%), a dose of 1 mg/kg of rocuronium was used, and in one service, 1.2 mg/kg (8.3%) was used. No services using rocuronium carried sugammadex. In five services, slower relaxation time was found using rocuronium (41.7%), and in seven services, no difference in intubation conditions were noted (58.3%). Contraindications to rocuronium use included high probability of difficult airway and anaphylaxis. Use of rocuronium as first-line muscle relaxant in prehospital RSI is increasing. Continued auditing of practice will ascertain which services have adopted change and identify if complications of failed intubation increase as a result.

  9. Three-way modelling of NMR relaxation profiles from thawed cod muscle

    DEFF Research Database (Denmark)

    Jensen, Kristina Nedenskov; Guldager, Helle Skov; Jørgensen, Bo Munk

    2002-01-01

    Low-field 1H nuclear magnetic resonance transverse relaxation was used to measure water mobility and distribution in cod stored at -20°C or -30°C for up to 12 months and subsequently from 0 to 21 days in modified atmosphere at +2°C. The relaxation profiles were decomposed by parallel factor analy...

  10. [Impact of a quality assurance program on the use of neuromuscular monitoring and reversal of muscle relaxants].

    Science.gov (United States)

    Motamed, C; Bourgain, J-L

    2009-04-01

    As part of a quality assurance in the anaesthesia department, this study was designed to enhance the rate of neuromuscular blockade monitoring for patients receiving muscle relaxant during anaesthesia. After approval of our local ethical committee, we assessed 200 computerized anaesthesia records in which neuromuscular relaxants were used. The following data were collected: demographic characteristics, durations of anaesthesia and surgery, use of neuromuscular monitoring, reversal agents and the quality of neuromuscular monitoring. The results were discussed with all anaesthesia providers of the department and an internal guideline was elaborated with the endpoint that all patients having muscle relaxants should have quantitative neuromuscular monitoring. Six months later, another assessment of 200 consecutive records collected the same data to check the efficiency of the elaborated guideline. The monitoring rate was of 67% at the first assessment and increased to 94% (passessment and was stable at the second assessment (50%). The rate of patients not monitored and not reversed decreased from 5 to 2% (pquality assurance program systematic quantitative monitoring of neuromuscular blockade can be significantly increased.

  11. Cardio-respiratory response of young adult Indian male subjects to stress: Effects of progressive muscle relaxation

    Directory of Open Access Journals (Sweden)

    Arunima Chaudhuri

    2014-01-01

    Full Text Available Background: Stress and anxiety have become an integral part of our lives. Of late, this has resulted in the increase in incidence of hypertension and coronary heart disease. Objectives: To assess the effect of progressive muscle relaxation (PMR on young adult males and its role in the modulation of cardio-respiratory response on exposure to stress. Materials and Methods: This prospective cross-sectional study was conducted in a tertiary care referral hospital. Undergraduate male students under stress were chosen for the study. Fasting blood samples were drawn to analyze sugar and lipid profile, followed by anthropometric measurements and ECG. In the resting condition, blood pressure, pulse rate, and spirometric parameters; forced vital capacities (FVC, and forced expiratory volume in 1 sec (FEV 1 % were measured. Then, they were made to exercise with bicycle ergometer and post exercise, the vital parameters were recorded. All subjects were given a training of Jacobson′s Progressive Muscular Relaxation and asked to practice this technique for 3 months. All parameters were re-evaluated. Results: Significant decreases in resting heart rate, systolic blood pressure and diastolic blood pressure, total cholesterol, triglyceride, and low density lipoprotein (LDL cholesterol levels of subjects were seen after PMR training. Exercise-induced rise in heart rate and blood pressure were also significantly less in subjects following PMR training. Conclusion: Progressive muscle relaxation helps in modulation of heart rate, blood pressure, and lipid profile in healthy normal adult male individuals.

  12. The effect of control of diabetes mellitus on plasma T4, T3, rT3 levels and half muscle relaxation period

    International Nuclear Information System (INIS)

    Ismail, A.A.; Hafiez, A.A.; Sayed, S.N.; Abbas, E.Z.; Halawa, F.A.; Youssef, M.M.

    1984-01-01

    25 diabetics of the maturity onset type who showed no clinical evidence of either peripheral neruropathy or diabetic amyotrophy were selected for this study. All patients were subjected to the following investigations: estimation of half muscle relaxation period of the quadriceps muscle knee-jerk, measurement of plasma levels of thyroxine (T 4 ), triiodothyronine (T 3 ) and reverse triiodothronine (rT 3 ), determination of fasting and two hours postprandial blood sugar levels. The quadriceps muscle relaxation period in uncontrolled diabetics was significantly longer than in normals. Control of diabetes by glibenclamide or gliclazide did not cause a significant change in muscle relaxation period. There was also no significant difference between the effects of the two drugs. (author)

  13. Arginase attenuates inhibitory nonadrenergic noncholinergic nerve-induced nitric oxide generation and airway smooth muscle relaxation

    Directory of Open Access Journals (Sweden)

    Meurs Herman

    2005-03-01

    Full Text Available Abstract Background Recent evidence suggests that endogenous arginase activity potentiates airway responsiveness to methacholine by attenuation of agonist-induced nitric oxide (NO production, presumably by competition with epithelial constitutive NO synthase for the common substrate, L-arginine. Using guinea pig tracheal open-ring preparations, we now investigated the involvement of arginase in the modulation of neuronal nitric oxide synthase (nNOS-mediated relaxation induced by inhibitory nonadrenergic noncholinergic (iNANC nerve stimulation. Methods Electrical field stimulation (EFS; 150 mA, 4 ms, 4 s, 0.5 – 16 Hz-induced relaxation was measured in tracheal preparations precontracted to 30% with histamine, in the presence of 1 μM atropine and 3 μM indomethacin. The contribution of NO to the EFS-induced relaxation was assessed by the nonselective NOS inhibitor L-NNA (0.1 mM, while the involvement of arginase activity in the regulation of EFS-induced NO production and relaxation was investigated by the effect of the specific arginase inhibitor nor-NOHA (10 μM. Furthermore, the role of substrate availability to nNOS in EFS-induced relaxation was measured in the presence of various concentrations of exogenous L-arginine. Results EFS induced a frequency-dependent relaxation, ranging from 6.6 ± 0.8% at 0.5 Hz to 74.6 ± 1.2% at 16 Hz, which was inhibited with the NOS inhibitor L-NNA by 78.0 ± 10.5% at 0.5 Hz to 26.7 ± 7.7% at 8 Hz (P Conclusion The results indicate that endogenous arginase activity attenuates iNANC nerve-mediated airway relaxation by inhibition of NO generation, presumably by limiting L-arginine availability to nNOS.

  14. Characterization of P2Y receptors mediating ATP induced relaxation in guinea pig airway smooth muscle: involvement of prostaglandins and K+ channels.

    Science.gov (United States)

    Montaño, Luis M; Cruz-Valderrama, José E; Figueroa, Alejandra; Flores-Soto, Edgar; García-Hernández, Luz M; Carbajal, Verónica; Segura, Patricia; Méndez, Carmen; Díaz, Verónica; Barajas-López, Carlos

    2011-10-01

    In airway smooth muscle (ASM), adenosine 5'-triphosphate (ATP) induces a relaxation associated with prostaglandin production. We explored the role of K(+) currents (I (K)) in this relaxation. ATP relaxed the ASM, and this effect was abolished by indomethacin. Removal of airway epithelium slightly diminished the ATP-induced relaxation at lower concentration without modifying the responses to ATP at higher concentrations. ATPγS and UTP induced a concentration-dependent relaxation similar to ATP; α,β-methylene-ATP was inactive from 1 to 100 μM. Suramin or reactive blue 2 (RB2), P2Y receptor antagonists, did not modify the relaxation, but their combination significantly reduced this effect of ATP. The relaxation was also inhibited by N-ethylmaleimide (NEM; which uncouples G proteins). In myocytes, the ATP-induced I (K) increment was not modified by suramin or RB2 but the combination of both drugs abolished it. This increment in the I (K) was also completely nullified by NEM and SQ 22,536. 4-Amynopyridine or iberiotoxin diminished the ATP-induced I (K) increment, and the combination of both substances diminished ATP-induced relaxation. The presence of P2Y(2) and P2Y(4) receptors in smooth muscle was corroborated by Western blot and confocal images. In conclusion, ATP: (1) produces relaxation by inducing the production of bronchodilator prostaglandins in airway smooth muscle, most likely by acting on P2Y(4) and P2Y(2) receptors; (2) induces I (K) increment through activation of the delayed rectifier K(+) channels and the high-conductance Ca(2+)-dependent K(+) channels, therefore both channels are implicated in the ATP-induced relaxation; and (3) this I (K) increment is mediated by prostaglandin production which in turns increase cAMP signaling pathway.

  15. Influenza A infection attenuates relaxation responses of mouse tracheal smooth muscle evoked by acrolein.

    Science.gov (United States)

    Cheah, Esther Y; Mann, Tracy S; Burcham, Philip C; Henry, Peter J

    2015-02-15

    The airway epithelium is an important source of relaxant mediators, and damage to the epithelium caused by respiratory tract viruses may contribute to airway hyperreactivity. The aim of this study was to determine whether influenza A-induced epithelial damage would modulate relaxation responses evoked by acrolein, a toxic and prevalent component of smoke. Male BALB/c mice were inoculated intranasally with influenza A/PR-8/34 (VIRUS-infected) or allantoic fluid (SHAM-infected). On day 4 post-inoculation, isometric tension recording studies were conducted on carbachol pre-contracted tracheal segments isolated from VIRUS and SHAM mice. Relaxant responses to acrolein (30 μM) were markedly smaller in VIRUS segments compared to SHAM segments (2 ± 1% relaxation vs. 28 ± 5%, n=14, pacrolein and SP were reduced in VIRUS segments (>35% reduction, n=6, pacrolein were profoundly diminished in tracheal segments isolated from influenza A-infected mice. The mechanism through which influenza A infection attenuates this response appears to involve reduced production of PGE2 in response to SP due to epithelial cell loss, and may provide insight into the airway hyperreactivity observed with influenza A infection. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Effect of hypothyroidism on the nitrergic relaxant responses of corpus cavernosal smooth muscle in rabbits.

    Science.gov (United States)

    Sarac, Bulent; Yildirim, Mustafa K; Bagcivan, Ihsan; Kaya, Kemal; Kilicarslan, Hakan; Yildirim, Sahin

    2006-01-01

    The incidence of hormonal dysfunction as a cause of impotence remains controversial. However, several recent studies have reported evidence of hormonal abnormalities in 25-35% of impotent men. Hypothyroidism has been reported to occur in 6% of impotent men. In the present study, we examined nitrergic responses in hypothyroidism in rabbit corpus cavernosum and compared them with controls. Carbachol-induced relaxation responses and electrical field stimulation (EFS)-induced frequency-dependent relaxations decreased significantly in hypothyroid rabbits. Papaverine and sodium nitroprusside (SNP)-induced relaxation responses did not change significantly in hypothyroid rabbits. The contraction responses of phenylephrine and EFS-induced frequency-dependent contractions were significantly decreased in the hypothyroid group. We can speculate that the reduction of relaxant responses to EFS and carbachol in hypothyroid rabbits can depend on a decreased release of nitric oxide (NO) from nitrergic nerves and endothelium or a reduction of muscarinic receptor density. Also, decreases in contraction responses may depend on diminished adrenoceptor density.

  17. Behaviour of motor units of human arm muscles: differences between slow isometric contraction and relaxation

    NARCIS (Netherlands)

    Denier van der Gon, J.J.; Haar Romenij, ter B.M.; Zuylen, Van E.J.

    1985-01-01

    The behaviour of motor units in the m. biceps brachii (long head), in the m. brachialis and in the m. supinator during slow isometric contraction and relaxation was studied when subjects were performing different motor tasks. These tasks were: flexion of the elbow joint, supination of the forearm

  18. Cyanide and sulfide interact with nitrogenous compounds to influence the relaxation of various smooth muscles

    Energy Technology Data Exchange (ETDEWEB)

    Kruszyna, H.; Kruszyna, R.; Smith, R.P.

    1985-05-01

    Sodium nitroprusside relaxed guinea pig ileum after the segment had been submaximally contracted by either histamine or acetylcholine, intact isolated rabbit gall bladder after submaximal contraction by either acetylcholine or cholecystokinin octapeptide, and rat pulmonary artery helical strips after submaximal contraction with norepinephrine. In each of these cases the relaxation produced by nitroprusside was at least partially reversed by the subsequent addition of excess sodium cyanide. Cyanide, however, in nontoxic concentrations did not reverse the spasmolytic effects of hydroxylamine hydrochloride, sodium azide, nitroglycerin, sodium nitrite, or nitric oxide hemoglobin on guinea pig ileum, nor did cyanide alone in the same concentrations have any effect. The similar interaction between nitroprusside and cyanide on rabbit aortic strips is not dependent on the presence of an intact endothelia cell layer. Also, on rabbit aortic strips and like cyanide, sodium sulfide reversed the spasmolytic effects of azide and hydroxylamine, but it had little or no effect on the relaxation induced by papaverine. Unlike cyanide, however, sulfide augmented the relaxation induced by nitroprusside, and it reversed the effects of nitric oxide hemoglobin, nitroglycerin, and nitrite. A direct chemical reaction between sulfide and nitroprusside may account for the difference between it and cyanide. Although evidence was obtained also for a direct chemical reaction between sulfide and norepinephrine, that reaction does not seem to have played a role in these results.

  19. Comparing the Effects of Progressive Muscle Relaxation and Guided Imagery on sleep quality in primigravida women referring to Mashhad health care centers-1393

    OpenAIRE

    Nahid Golmakani; Farnaz Sadat Seyed Ahmadi Nejad; Mohammad Taghi Shakeri; Negar Asghari Pour

    2015-01-01

    Background & aim: Decreased sleep quality is a common complaint during pregnancy. Relaxation is one of the non-pharmaceutical treatments for sleep disorders. Different techniques could have different impacts on various biological and mental stressors. Therefore, this study aimed to compare the effects of progressive muscle relaxation and guided imagery on the sleep quality of primigravida women. Methods:This three-group clinical trial was conducted on 100 primigravida women, referring to Mash...

  20. Sexual dimorphism of extensor carpi radialis muscle size, isometric force, relaxation rate and stamina during the breeding season of the frog Rana temporaria Linnaeus 1758.

    Science.gov (United States)

    Navas, Carlos A; James, Rob S

    2007-02-01

    Mating success of individual male frogs within explosive breeding species can depend on their ability to compete for a mate and to hold onto that mate during amplexus. Such importance of amplexus has resulted in the evolution of sexual dimorphism in the morphology and contractile characteristics of the anuran forelimb muscles used during amplexus. The aims of our study were to use an explosive breeding frog (Rana temporaria) during the breeding season to compare extensor carpi radialis (ECR) muscle length, mass, isometric activation times, relaxation times, absolute force, relative force (stress) and fatigue between male and female frogs. We found that ECR muscle mass and length were greater (tenfold and 1.4-fold, respectively), absolute tetanic muscle force and relative tetanic force (stress) were greater (16-fold and 2.2-fold, respectively) and relaxation times were slower in males than in females. Male ECR muscles incompletely relaxed during fatigue tests and showed less fatigue than female muscles. These sex differences are likely to be beneficial to the male frogs in allowing them to produce relatively high absolute muscle forces for prolonged periods of time to hold onto their mate during amplexus.

  1. Neck muscle fatigue alters the cervical flexion relaxation ratio in sub-clinical neck pain patients.

    Science.gov (United States)

    Zabihhosseinian, Mahboobeh; Holmes, Michael W R; Ferguson, Brad; Murphy, Bernadette

    2015-06-01

    The cervical flexion relaxation ratio is lower in neck pain patients compared to healthy controls. Fatigue modulates the onset and offset angles of the silent period in both the lumbar and cervical spine in healthy individuals; however, this response has not been studied with neck pain patients. The purpose of this study was to determine if cervical extensor fatigue would alter the parameters of the cervical flexion relaxation more in a neck pain group than a healthy control group. Thirteen healthy and twelve neck pain patients participated. Cervical extensor activity was examined bilaterally and kinematics of the neck and head were collected. An isometric, repetitive neck extension task at 70% of maximum elicited fatigue. Participants performed 3 trials of maximal cervical flexion both pre and post fatigue. The healthy controls and neck pain groups fatigued after 56 (41) and 39 (31) repetitions, respectively. There was a significant interaction effect for the flexion relaxation ratio between the control and neck pain groups from pre to post fatigue trials (F1,96=22.67, P=0.0001), but not for onset and offset angles (F1, 96=0.017, P=0.897), although the onset and offset angles did decrease significantly for both groups following fatigue (F1,96=9.26, P=0.002). Individuals with mild to moderate neck pain have significant differences in their neuromuscular control relative to controls, experienced myoelectric fatigue with fewer repetitions in a shorter time, had a lower cervical flexion relaxation ratio at baseline and had an inability to decrease this ratio further in response to fatigue. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. How are we behaving?

    CERN Multimedia

    2012-01-01

    It’s almost two years since CERN introduced a Code of Conduct. The results may not be immediately measurable, but I’d like to think it’s made the lab a better place to be. The Code of Conduct is based on values that most of us immediately identify with, and so implementing it comes as second nature. Nevertheless, in an organisation of over 10,000 people, it’s useful to have a set of guidelines and there have been occasions on which it’s been necessary to remind people of them.   I use the figure of 10,000 advisedly since the Code of Conduct applies to us all, those on the CERN payroll as well as users of the lab’s facilities and people working for CERN contractors, as long as they are acting on CERN’s behalf. The Code also applies to us whether we are on the CERN site or anywhere else. CERN is a major presence in the region. The way we behave can have a significant influence on how our neighbours perceive us, and how the la...

  3. Comparison of the Hamstring Muscle Activity and Flexion-Relaxation Ratio between Asymptomatic Persons and Computer Work-related Low Back Pain Sufferers.

    Science.gov (United States)

    Kim, Min-Hee; Yoo, Won-Gyu

    2013-05-01

    [Purpose] The purpose of this study was to compare the hamstring muscle (HAM) activities and flexion-relaxation ratios of an asymptomatic group and a computer work-related low back pain (LBP) group. [Subjects] For this study, we recruited 10 asymptomatic computer workers and 10 computer workers with work-related LBP. [Methods] We measured the RMS activity of each phase (flexion, full-flexion, and re-extension phase) of trunk flexion and calculated the flexion-relaxation (FR) ratio of the muscle activities of the flexion and full-flexion phases. [Results] In the computer work-related LBP group, the HAM muscle activity increased during the full-flexion phase compared to the asymptomatic group, and the FR ration was also significantly higher. [Conclusion] We thought that prolonged sitting of computer workers might cause the change in their HAM muscle activity pattern.

  4. In vivo field dependence of proton relaxation times in human brain, liver and skeletal muscle: a multicenter study

    DEFF Research Database (Denmark)

    Henriksen, O; de Certaines, J D; Spisni, A

    1993-01-01

    and MRS, the in vivo field dispersion of T1 and T2 has been measured in order to evaluate whether ex vivo data are representative for the in vivo situation. Brain, skeletal muscle, and liver of healthy human volunteers were studied. Fifteen MR units with a field strength ranging from 0.08 T to 1.5 T took......T1 and T2 relaxation times are fundamental parameters for signal contrast behaviour in MRI. A number of ex vivo relaxometry studies have dealt with the magnetic field dispersion of T1. By means of multicenter study within the frame of the COMAC BME Concerted Action on Tissue Characterization by MRI......, whereas no significant variations were seen for T2. Our in vivo data were generally in reasonable agreement with proposed models based on ex vivo measurements....

  5. Both physical exercise and progressive muscle relaxation reduce the facing-the-viewer bias in biological motion perception.

    Directory of Open Access Journals (Sweden)

    Adam Heenan

    Full Text Available Biological motion stimuli, such as orthographically projected stick figure walkers, are ambiguous about their orientation in depth. The projection of a stick figure walker oriented towards the viewer, therefore, is the same as its projection when oriented away. Even though such figures are depth-ambiguous, however, observers tend to interpret them as facing towards them more often than facing away. Some have speculated that this facing-the-viewer bias may exist for sociobiological reasons: Mistaking another human as retreating when they are actually approaching could have more severe consequences than the opposite error. Implied in this hypothesis is that the facing-towards percept of biological motion stimuli is potentially more threatening. Measures of anxiety and the facing-the-viewer bias should therefore be related, as researchers have consistently found that anxious individuals display an attentional bias towards more threatening stimuli. The goal of this study was to assess whether physical exercise (Experiment 1 or an anxiety induction/reduction task (Experiment 2 would significantly affect facing-the-viewer biases. We hypothesized that both physical exercise and progressive muscle relaxation would decrease facing-the-viewer biases for full stick figure walkers, but not for bottom- or top-half-only human stimuli, as these carry less sociobiological relevance. On the other hand, we expected that the anxiety induction task (Experiment 2 would increase facing-the-viewer biases for full stick figure walkers only. In both experiments, participants completed anxiety questionnaires, exercised on a treadmill (Experiment 1 or performed an anxiety induction/reduction task (Experiment 2, and then immediately completed a perceptual task that allowed us to assess their facing-the-viewer bias. As hypothesized, we found that physical exercise and progressive muscle relaxation reduced facing-the-viewer biases for full stick figure walkers only. Our

  6. Rock Tea extract (Jasonia glutinosa) relaxes rat aortic smooth muscle by inhibition of L-type Ca(2+) channels.

    Science.gov (United States)

    Valero, Marta Sofía; Oliván-Viguera, Aida; Garrido, Irene; Langa, Elisa; Berzosa, César; López, Víctor; Gómez-Rincón, Carlota; Murillo, María Divina; Köhler, Ralf

    2015-12-01

    In traditional herbal medicine, Rock Tea (Jasonia glutinosa) is known for its prophylactic and therapeutic value in various disorders including arterial hypertension. However, the mechanism by which Rock Tea exerts blood pressure-lowering actions has not been elucidated yet. Our aim was to demonstrate vasorelaxing effects of Rock Tea extract and to reveal its possible action mechanism. Isometric myography was conducted on high-K+-precontracted rings from rat thoracic aorta and tested extracts at concentrations of 0.5-5 mg/ml. Whole-cell patch-clamp experiments were performed in rat aortic vascular smooth muscle cells (line A7r5) to determine blocking effects on L-type Ca(2+) channels. Rock Tea extract relaxed the aorta contracted by high [K+] concentration dependently with an EC50 of ≈2.4 mg/ml and produced ≈75 % relaxation at the highest concentration tested. The L-type Ca(2+) channel blocker, verapamil (10(-6) M), had similar effects. Rock Tea extract had no effect in nominally Ca(2+)-free high-K(+) buffer but significantly inhibited contractions to re-addition of Ca(2+). Rock Tea extract inhibited the contractions induced by the L-type Ca(2+) channel activator Bay K 8644 (10(-5) M) and by phenylephrine (10(-6) M). Rock Tea extract and Y-27632 (10(-6) M), Rho-kinase inhibitor, had similar effects and the respective effects were not additive. Patch-clamp experiments demonstrated that Rock Tea extract (2.5 mg/ml) virtually abolished L-type Ca(2+) currents in A7r5. We conclude that Rock Tea extract produced vasorelaxation of rat aorta and that this relaxant effect is mediated by inhibition of L-type Ca(2+) channels. Rock Tea extracts may be of phytomedicinal value for prevention and adjuvant treatment of hypertension and other cardiovascular diseases.

  7. Comparing the Effects of Progressive Muscle Relaxation and Guided Imagery on sleep quality in primigravida women referring to Mashhad health care centers-1393

    Directory of Open Access Journals (Sweden)

    Nahid Golmakani

    2015-04-01

    Full Text Available Background & aim: Decreased sleep quality is a common complaint during pregnancy. Relaxation is one of the non-pharmaceutical treatments for sleep disorders. Different techniques could have different impacts on various biological and mental stressors. Therefore, this study aimed to compare the effects of progressive muscle relaxation and guided imagery on the sleep quality of primigravida women. Methods:This three-group clinical trial was conducted on 100 primigravida women, referring to Mashhad health care centers in 2014. All women, who met the inclusion criteria, were randomly assigned to three groups: progressive muscle relaxation, guided imagery, and control groups. The intervention groups performed the exercises twice a day for a period of four weeks at home after two sessions of relaxation training (held during two weeks. Then, the quality of sleep was measured using Pittsburgh Sleep Quality Index. For data analysis, ANOVA, Kruskal-Wallis, paired t-test, and post-hoc test were performed, using SPSS version 11.5. Results: The total score of sleep quality and its components (except use of sleep medication was significantly lower after the intervention, compared to the pre-intervention period in progressive muscle relaxation and guided imagery groups (P

  8. Quantitative Assessment of the T2 Relaxation Time of the Gluteus Muscles in Children with Duchenne Muscular Dystrophy: a Comparative Study Before and After Steroid Treatment

    International Nuclear Information System (INIS)

    Kim, Hee Kyung; Laor, Tal; Wong, Brenda; Horn, Paul S.

    2010-01-01

    To determine the feasibility of using T2 mapping as a quantitative method to longitudinally follow the disease activity in children with Duchenne muscular dystrophy (DMD) who are treated with steroids. Eleven boys with DMD (age range: 5-14 years) underwent evaluation with the clinical functional score (CFS), and conventional pelvic MRI and T2 mapping before and during steroid therapy. The gluteus muscle inflammation and fatty infiltration were evaluated on conventional MRI. The histograms and mean T2 relaxation times were obtained from the T2 maps. The CFS, the conventional MRI findings and the T2 values were compared before and during steroid therapy. None of the patients showed interval change of their CFSs. On conventional MRI, none of the images showed muscle inflammation. During steroid treatment, two boys showed increased fatty infiltration on conventional MRI, and both had an increase of the mean T2 relaxation time (p < 0.05). The remaining nine boys had no increase in fatty infiltration. Of these, three showed an increased mean T2 relaxation time (p < 0.05), two showed no change and four showed a decreased mean T2 relaxation time (p < 0.05). T2 mapping is a feasible technique to evaluate the longitudinal muscle changes in those children who receive steroid therapy for DMD. The differences of the mean T2 relaxation time may reflect alterations in disease activity, and even when the conventional MRI and CFS remain stable

  9. Quantitative Assessment of the T2 Relaxation Time of the Gluteus Muscles in Children with Duchenne Muscular Dystrophy: a Comparative Study Before and After Steroid Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hee Kyung; Laor, Tal; Wong, Brenda [Cincinnati Children' s Hospital Medical Center, Cincinnati (United States); Horn, Paul S. [University of Cincinnati, Cincinnati (United States)

    2010-06-15

    To determine the feasibility of using T2 mapping as a quantitative method to longitudinally follow the disease activity in children with Duchenne muscular dystrophy (DMD) who are treated with steroids. Eleven boys with DMD (age range: 5-14 years) underwent evaluation with the clinical functional score (CFS), and conventional pelvic MRI and T2 mapping before and during steroid therapy. The gluteus muscle inflammation and fatty infiltration were evaluated on conventional MRI. The histograms and mean T2 relaxation times were obtained from the T2 maps. The CFS, the conventional MRI findings and the T2 values were compared before and during steroid therapy. None of the patients showed interval change of their CFSs. On conventional MRI, none of the images showed muscle inflammation. During steroid treatment, two boys showed increased fatty infiltration on conventional MRI, and both had an increase of the mean T2 relaxation time (p < 0.05). The remaining nine boys had no increase in fatty infiltration. Of these, three showed an increased mean T2 relaxation time (p < 0.05), two showed no change and four showed a decreased mean T2 relaxation time (p < 0.05). T2 mapping is a feasible technique to evaluate the longitudinal muscle changes in those children who receive steroid therapy for DMD. The differences of the mean T2 relaxation time may reflect alterations in disease activity, and even when the conventional MRI and CFS remain stable.

  10. The Effects of Group Relaxation Training/Large Muscle Exercise, and Parental Involvement on Attention to Task, Impulsivity, and Locus of Control among Hyperactive Boys.

    Science.gov (United States)

    Porter, Sally S.; Omizo, Michael M.

    1984-01-01

    The study examined the effects of group relaxation training/large muscle exercise and parental involvement on attention to task, impulsivity, and locus of control among 34 hyperactive boys. Following treatment both experimental groups recorded significantly higher attention to task, lower impulsivity, and lower locus of control scores. (Author/CL)

  11. The Use of a Microcomputer in Collecting Data from Cardiovascular Experiments on Muscle Relaxants

    Science.gov (United States)

    Thut, Paul D.; Polansky, Gregg; Pruzansky, Elysa

    1983-01-01

    The possible association of cardiovascular side-effects from potentially, clinically useful non-depolarizing neuromuscular blocking drugs has been studied with the aid of a micro- computer. The maximal changes in heart rate, systolic, diastolic and mean arterial pressure and pulse pressure were recorded in the onset, maximal effect and recovery phase of relaxant activity in dogs anesthetized with isoflurane. The data collection system employed a Gould 2800S polygraph, an Apple II Plus microcomputer, a Cyborg Corp. ‘Issac’ 12 bit analog to digital converter, two 5 1/4″ floppy disk drives, a ‘Videoterm’ 80 column display board and a 12″ green phosphor monitor. Prior to development of the computer system, direct analysis of polygraph records required more than three times more time than the actual experiment. With the aid of the computer, analysis of data, tabular and graphic presentation and narrative reports were completed within 15 minutes after the end of the experiment.

  12. Evaluation of dysthyroid optic neuropathy using T2-relaxation time of extraocular muscle as parameter

    International Nuclear Information System (INIS)

    Yu, Fumihiko; Maeda, Toshine; Inoue, Toyoko; Inoue, Yoichi

    2001-01-01

    The T2 value of magnetic resonance imaging (MRI) is useful in evaluating the activity of dysthyroid ophthlamopathy. We applied this method in evaluating dysthyroid optic neuropathy in 15 affected eyes of 15 patients. Another group of 40 eyes of 20 patients of dysthyroid opthalmopathy without hypertrophy of extraocular muscles served as control. The T2 value in dysthyroid optic neuropathy significantly decreased following treatment with corticosteroid but the value was still higher than that in control eyes. The findings show that the T2 value of MRI is useful in evaluating the therapeutic effect of dysthyroid optic neuropathy. (author)

  13. Evaluation of dysthyroid optic neuropathy using T2-relaxation time of extraocular muscle as parameter

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Fumihiko; Maeda, Toshine; Inoue, Toyoko; Inoue, Yoichi [Olympia Eye Hospital, Tokyo (Japan)

    2001-11-01

    The T2 value of magnetic resonance imaging (MRI) is useful in evaluating the activity of dysthyroid ophthlamopathy. We applied this method in evaluating dysthyroid optic neuropathy in 15 affected eyes of 15 patients. Another group of 40 eyes of 20 patients of dysthyroid opthalmopathy without hypertrophy of extraocular muscles served as control. The T2 value in dysthyroid optic neuropathy significantly decreased following treatment with corticosteroid but the value was still higher than that in control eyes. The findings show that the T2 value of MRI is useful in evaluating the therapeutic effect of dysthyroid optic neuropathy. (author)

  14. Efficacy of Progressive Muscle Relaxation Training on Anxiety, Depression and Quality of Life in Cancer Patients Undergoing Chemotherapy at Tabriz Hematology and Oncology Research Center, Iran in 2010

    Directory of Open Access Journals (Sweden)

    Reza Shabanlui

    2012-01-01

    Full Text Available Background: Chemotherapy is an important treatment for cancer, yet some of its side effects are serious and painful. Many patients with cancer suffer from psychiatric disorders that most likely result from therapeutic drugs or mental strategies to cope with their illness. Progressive muscle relaxation is one of the cost effective, self-help methods that promotes mental health in healthy participants. Thisstudy aims to determine the effect of progressive muscle relaxation training on anxiety and depression in cancer patients undergoing chemotherapy.Methods: This was a randomized, clinical study that enrolled 60 patients who received inpatient chemotherapy in the Tabriz Hematology and Oncology Research Center in 2010. We divided patients into two groups, intervention and control. All participants signed written formal consents and completed the Hospital Anxiety & Depression Scale questionnaires. Intervention group participants were trained inprogressive muscle relaxation in groups of 3-6 to enable participants to perform this technique when they were alone in the hospital and after discharge, two to three times each day. After one and three months, questionnaires were completed again by both groups and the results compared. 17th version of SPSS software was used fordata analysis.Results: After data analysis, most participants were satisfied with learning and experiencing this technique. There was no significant difference between scales in the case and control groups after one month (P>0.05. However after three months, anxiety and depression considerably improved in patients who underwent progressive muscle relaxation training (P<0.05.Conclusion: Progressive muscle relaxation training can improve anxietyand depression in cancer patients.

  15. The ultrasound-guided nerve blocks of abdominal wall contributed to anesthetic management of cholecystectomy in a patient with Becker muscular dystrophy without using muscle relaxants.

    Science.gov (United States)

    Iwata, Masato; Kuzumoto, Naoya; Akasaki, Yuka; Morioka, Masayo; Nakayama, Kana; Matsuzawa, Nobuyoshi; Kimoto, Katsuhiro; Shimomura, Toshiyuki

    2017-01-01

    Becker muscular dystrophy (BMD) is a progressive neuromuscular disorder caused by mutations in the dystrophin gene. The sensitivity to non-depolarizing muscle relaxant in a patient with muscle dystrophy is reportedly higher than that in normal individuals, and the duration of the effect is known to be prolonged. In this report, we present the case of a 58-year-old man with BMD who underwent laparoscopic cholecystectomy for symptomatic cholelithiasis under total intravenous anesthesia without the use of muscle-relaxant drugs and supplemented with regional anesthesia. Anesthesia was induced and maintained with propofol, remifentanil, and fentanyl; ultrasound-guided bilateral rectus sheath block (RSB) and right-sided subcostal transversus abdominis plane block (TAP) were performed. The procedure required conversion to open surgery because of hard conglutination; intraoperative and postoperative periods were uneventful. Adequate analgesia was maintained after extubation because of the effect of RSB and TAP.

  16. Effects of Fentanyl-lidocaine-propofol and Dexmedetomidine-lidocaine-propofol on Tracheal Intubation Without Use of Muscle Relaxants

    Directory of Open Access Journals (Sweden)

    Volkan Hancı

    2010-05-01

    Full Text Available The aim of this study was to compare the effects of fentanyl or dexmedetomidine when used in combination with propofol and lidocaine for tracheal intubation without using muscle relaxants. Sixty patients with American Society of Anesthesiologists stage I risk were randomized to receive 1 mg/kg dexmedetomidine (Group D, n = 30 or 2 mg/kg fentanyl (Group F, n = 30, both in combination with 1.5 mg/kg lidocaine and 3 mg/kg propofol. The requirement for intubation was determined based on mask ventilation capability, jaw motility, position of the vocal cords and the patient's response to intubation and inflation of the endotracheal tube cuff. Systolic arterial pressure, mean arterial pressure, heart rate and peripheral oxygen saturation values were also recorded. Rate pressure products were calculated. Jaw relaxation, position of the vocal cords and patient's response to intubation and inflation of the endotracheal tube cuff were significantly better in Group D than in Group F (p < 0.05. The intubation conditions were significantly more satisfactory in Group D than in Group F (p = 0.01. Heart rate was significantly lower in Group D than in Group F after the administration of the study drugs and intubation (p < 0.05. Mean arterial pressure was significantly lower in Group F than in Group D after propofol injection and at 3 and 5 minutes after intubation (p < 0.05. After intubation, the rate pressure product values were significantly lower in Group D than in Group F (p < 0.05. We conclude that endotracheal intubation was better with the dexmedetomidine–lidocaine–propofol combination than with the fentanyl–lidocaine–propofol combination. However, side effects such as bradycardia should be considered when using dexmedetomidine.

  17. The Effect of Ratio of Contraction to Relaxation Durations in PNF Exercises on the Muscle Strength and Range of Motion of Hip Joint

    Directory of Open Access Journals (Sweden)

    Hossein Rashedi

    2015-09-01

    Full Text Available Objective: The aim of the present study was to compare the effect of ratios of contraction- Relaxation on the muscle strength and range of motion of hip joint in PNF exercises. Methods: Thirty nine nonathletic male students (Mean±SD; age, 13±1.2 years; body mass, 55±9.8 kg were assigned .Three groups designated as I, II and III groups. The ratios of contraction to relaxation periods for groups were 1, 2 and 3 respectively. Training program included three sessions per week (CR-PNF for 6 weeks. Measurements of hip extensors muscles stretch and strength were performed at the beginning and at the end of training using an inclinometer (during leg raise test and dynamometer. Data were analyzed using dependent samples t-test and one-way ANOVA. Results: The results of the present study showed significant increases in hip extensor muscles flexibility and strength for three groups. This increase the in the strength in group I equaled 6 kg, in group II 4 kg and in group III 7 kg. The amount of increase in the hip extensor muscles flexibility in group I, II and II were 15, 8 and 12 degrees, respectively. The increase in these two variables was significant and similar in all three groups. Conclusion: Different contraction to relaxation ratio normally, 0.5, 1 and 2, did not show any meaningful differences on hip extensor muscular strength and hip range of motion.

  18. Effects of electric paravertebral muscle relaxation processes in the athletes heart

    Directory of Open Access Journals (Sweden)

    D. V. Syshko

    2013-02-01

    Full Text Available Influence of paravertebrals miorelaxation on electric processes in a heart at sportsmen is studied. Paravertebrals miorelaxation was the complex of exercises in a water environment directed on the decline of tone of paravertebral muscles. Before and after it was used of paravertebrals miorelaxation registered the indexes of electrocardiography at the sportsmen engaged in the Greek-Roman fight (n=22 by football (n=24 and heavy athletics (n=25. It is got, that at the sportsmen of engaged in the Greek -Roman fight after paravertebrals miorelaxation QRS and QT were it was increased, and R-R and PQ went down. At the sportsmen of engaged in heavy athletics HR and PQ went down after paravertebrals miorelaxation, R-R, QRS and QT were it was increased. At the sportsmen of getting busy by football the PQ interval shortened, and QRS and QT has multiplied. Findings testify to the presence of different mechanisms of adaptation of the conducting system of heart in the conditions of influencing of paravertebrals miorelaxation. These distinctions are fated by two basic factors: by the functional being of the cardio-vessels system on the whole and functional being of sine knot and conducting system of heart in particular.

  19. behaved particle swarm optimization (QPSO)

    African Journals Online (AJOL)

    Administrator

    2011-06-13

    Jun 13, 2011 ... experiment results of L-glutamic acid fermentation process showed that our ... Key words: Soft-sensing model, quantum-behaved particle swarm optimization ... information about such biochemical variables is, in most practical ...

  20. Effects of Progressive Muscle Relaxation Exercises Accompanied by Music on Low Back Pain and Quality of Life During Pregnancy.

    Science.gov (United States)

    Akmeşe, Zehra Baykal; Oran, Nazan Tuna

    2014-01-01

    Back pain is commonly experienced by pregnant women. Evidence suggests that progressive muscle relaxation (PMR) therapy, a complementary therapy widely used by pregnant women, may improve the physical and psychological outcomes of pregnancy. The aim of this study was to investigate the effects of PMR training accompanied by music on perceived pain and quality of life (QOL) in pregnant women with low back pain (LBP). This was a prospective randomized controlled trial. The study was designed to examine the effects of PMR accompanied by music on pregnant women with LBP. In total, 66 pregnant women were assigned randomly to a PMR group or a control group (33 women in each). A personal information form was used as a data collection tool; a visual analog scale was used for measuring pain; and the Short Form-36 was used to evaluate QOL. The control and intervention groups were comparable at baseline. Significant differences were observed between the 2 groups after 4 and 8 weeks of intervention. The intervention group showed significant improvement in all QOL subscales after the intervention. The intervention group, but not the control group, showed significant improvement in perceived pain after the intervention. The intervention group experienced a greater decrease in perceived pain and improved QOL than the control group. Our findings show that PMR accompanied by music may be an effective therapy for improving pain and QOL in pregnant women with LBP. Large randomized studies are recommended to confirm these results. © 2014 by the American College of Nurse‐Midwives.

  1. Effectiveness of home-based cupping massage compared to progressive muscle relaxation in patients with chronic neck pain--a randomized controlled trial.

    Science.gov (United States)

    Lauche, Romy; Materdey, Svitlana; Cramer, Holger; Haller, Heidemarie; Stange, Rainer; Dobos, Gustav; Rampp, Thomas

    2013-01-01

    Chronic neck pain is a major public health problem with very few evidence-based complementary treatment options. This study aimed to test the efficacy of 12 weeks of a partner-delivered home-based cupping massage, compared to the same period of progressive muscle relaxation in patients with chronic non-specific neck pain. Patients were randomly assigned to self-directed cupping massage or progressive muscle relaxation. They were trained and asked to undertake the assigned treatment twice weekly for 12 weeks. Primary outcome measure was the current neck pain intensity (0-100 mm visual analog scale; VAS) after 12 weeks. Secondary outcome measures included pain on motion, affective pain perception, functional disability, psychological distress, wellbeing, health-related quality of life, pressure pain thresholds and adverse events. Sixty one patients (54.1±12.7 years; 73.8%female) were randomized to cupping massage (n = 30) or progressive muscle relaxation (n = 31). After treatment, both groups showed significantly less pain compared to baseline however without significant group differences. Significant effects in favor of cupping massage were only found for wellbeing and pressure pain thresholds. In conclusion, cupping massage is no more effective than progressive muscle relaxation in reducing chronic non-specific neck pain. Both therapies can be easily used at home and can reduce pain to a minimal clinically relevant extent. Cupping massage may however be better than PMR in improving well-being and decreasing pressure pain sensitivity but more studies with larger samples and longer follow-up periods are needed to confirm these results. ClinicalTrials.gov NCT01500330.

  2. Effectiveness of Home-Based Cupping Massage Compared to Progressive Muscle Relaxation in Patients with Chronic Neck Pain—A Randomized Controlled Trial

    Science.gov (United States)

    Lauche, Romy; Materdey, Svitlana; Cramer, Holger; Haller, Heidemarie; Stange, Rainer; Dobos, Gustav; Rampp, Thomas

    2013-01-01

    Chronic neck pain is a major public health problem with very few evidence-based complementary treatment options. This study aimed to test the efficacy of 12 weeks of a partner-delivered home-based cupping massage, compared to the same period of progressive muscle relaxation in patients with chronic non-specific neck pain. Patients were randomly assigned to self-directed cupping massage or progressive muscle relaxation. They were trained and asked to undertake the assigned treatment twice weekly for 12 weeks. Primary outcome measure was the current neck pain intensity (0–100 mm visual analog scale; VAS) after 12 weeks. Secondary outcome measures included pain on motion, affective pain perception, functional disability, psychological distress, wellbeing, health-related quality of life, pressure pain thresholds and adverse events. Sixty one patients (54.1±12.7 years; 73.8%female) were randomized to cupping massage (n = 30) or progressive muscle relaxation (n = 31). After treatment, both groups showed significantly less pain compared to baseline however without significant group differences. Significant effects in favor of cupping massage were only found for wellbeing and pressure pain thresholds. In conclusion, cupping massage is no more effective than progressive muscle relaxation in reducing chronic non-specific neck pain. Both therapies can be easily used at home and can reduce pain to a minimal clinically relevant extent. Cupping massage may however be better than PMR in improving well-being and decreasing pressure pain sensitivity but more studies with larger samples and longer follow-up periods are needed to confirm these results. Trial Registration ClinicalTrials.gov NCT01500330 PMID:23762355

  3. The impact of muscle relaxation techniques on the quality of life of cancer patients, as measured by the FACT-G questionnaire.

    Science.gov (United States)

    Parás-Bravo, Paula; Salvadores-Fuentes, Paloma; Alonso-Blanco, Cristina; Paz-Zulueta, María; Santibañez-Margüello, Miguel; Palacios-Ceña, Domingo; Boixadera-Planas, Ester; Fernández-de-Las-Peñas, César

    2017-01-01

    Patients with cancer frequently suffer from emotional distress, characterized by psychological symptoms such as anxiety or depression. The presence of psychological symptoms combined with the complex nature of oncology processes can negatively impact patients' quality of life. We aimed to determine the impact of a relaxation protocol on improving quality of life in a sample of oncological patients treated in the Spanish National Public Health System. We conducted a multicenter interventional study without a control group. In total, 272 patients with different oncologic pathologies and showing symptoms of anxiety were recruited from 10 Spanish public hospitals. The intervention comprised abbreviated progressive muscle relaxation training, according to Bernstein and Borkovec. This was followed by weekly telephone calls to each patient over a 1-month period. We collected sociodemographic variables related to the disease process, including information about mental health and the intervention. Patients' quality of life was assessed using the Functional Assessment of Cancer Therapy-General (FACT-G) questionnaire. Bivariate and univariate analyses were performed, along with an analysis of multiple correspondences to identify subgroups of patients with similar variations on the FACT-G. Patients showed statistically significant improvements on the FACT-G overall score (W = 16806; pPatients with cancer who learned and practiced abbreviated progressive muscle relaxation experienced improvement in their perceived quality of life as measured by the FACT-G. Our findings support a previous assumption that complementary techniques (including relaxation techniques) are effective in improving the quality of life of patients with cancer.

  4. [Effects of afloqualone, a centrally acting muscle relaxant, on the sleep-wakefulness cycle in cats with chronically implanted electrodes (author's transl)].

    Science.gov (United States)

    Kojima, M; Kudo, Y; Ishida, R

    1981-11-01

    The present study was carried out to elucidate whether or whether not afloqualone has a hypnotic action because of its similarity in chemical structure to methaqualone. In the sleep-wakefulness cycles during the 8-hour observation period (9:00-17:00), afloqualone increased the percentages of resting (REST) and slow wave light sleep (SWLS) stages at a dose of 25 mg/kg (p.o.), producing a moderate muscle relaxation. Even at a dose of 50 mg/kg (p.o.) where a marked muscle relaxation was produced, afloqualone had no influence on the percentage of slow wave deep sleep (SWDS) stage, though it increased the percentages of SWLS and decreased the percentages of awake (AWK), REST and fast wave sleep (FWS) stages. On the other hand, tolperisone . HCl, chlormezanone, methaqualone and pentobarbital . Na, used as the reference drugs, all increased the percentage of SWDS stage, but either decreased or had no effect on the percentages of the other four stages at pharmacologically effective doses. From these results it was concluded that afloqualone seems to be devoid of a hypnotic action and has different effects on the sleep-wakefulness cycle than those of both the hypnotics and the other muscle relaxants used.

  5. Quantitative assessment of the T2 relaxation time of the gluteus muscles in children with Duchenne muscular dystrophy: a comparative study before and after steroid treatment.

    Science.gov (United States)

    Kim, Hee Kyung; Laor, Tal; Horn, Paul S; Wong, Brenda

    2010-01-01

    To determine the feasibility of using T2 mapping as a quantitative method to longitudinally follow the disease activity in children with Duchenne muscular dystrophy (DMD) who are treated with steroids. ELEVEN BOYS WITH DMD (AGE RANGE: 5-14 years) underwent evaluation with the clinical functional score (CFS), and conventional pelvic MRI and T2 mapping before and during steroid therapy. The gluteus muscle inflammation and fatty infiltration were evaluated on conventional MRI. The histograms and mean T2 relaxation times were obtained from the T2 maps. The CFS, the conventional MRI findings and the T2 values were compared before and during steroid therapy. None of the patients showed interval change of their CFSs. On conventional MRI, none of the images showed muscle inflammation. During steroid treatment, two boys showed increased fatty infiltration on conventional MRI, and both had an increase of the mean T2 relaxation time (p muscle changes in those children who receive steroid therapy for DMD. The differences of the mean T2 relaxation time may reflect alterations in disease activity, and even when the conventional MRI and CFS remain stable.

  6. The effect of low dose rocuronium on globe position, muscle relaxation and ventilation in dogs: a clinical study.

    Science.gov (United States)

    Auer, Ulrike; Mosing, Martina; Moens, Yves P S

    2007-01-01

    The purpose of this study was to evaluate globe position, muscle relaxation and changes in ventilatory parameters after intravenous administration of 0.1 mg/kg rocuronium. Prospective clinical study. Sixteen dogs of different breeds, with a body weight of 22.1 +/- 13 kg and age of 5.6 +/- 2.8 years (mean +/- SD), were anesthetized for a short ophthalmic examination requiring central position of the globe. All dogs were premedicated with 0.005 mg/kg medetomidine and 0.1 mg/kg methadone IV. Anesthesia was induced with propofol to effect and maintained with 10 mg/kg/h propofol by continuous rate infusion. Following endotracheal intubation all dogs breathed 100% oxygen via an anesthetic circle system. Neuromuscular function was assessed with an acceleromyograph (TOF-Guard, Organon Teknika NV, Turnhout, Belgium) and by stimulation of the nervus peroneus superficialis. The ventilation parameters were measured using spirometry and capnography. After baseline measurements 0.1 mg/kg rocuronium was administered IV. Minute volume (MV), tidal volume (Vt), respiratory rate (RR), end expiratory carbon dioxide concentration (PE'CO(2)) and maximal depression of the response of the first twitch (T1) of train-of-four (TOF) stimulation and train-of-four ratio (TOFR) was measured. The change in the position of the globe was recorded. T1 decreased to 61 +/- 18% and the TOF ratio to 45 +/- 21% of baseline values. Both parameters returned to baseline after 9 min. There was no significant reduction in MV, TV and RR and no increase in PE'CO(2). The globe rotated to a central position of 45 +/- 7.7 s after administration of rocuronium and remained there for 23 +/- 10.8 min in all dogs. Rocuronium administered intravenously at a dose of 0.1 mg/kg to dogs causes a central position of the globe but minimal impairment of ventilation parameters.

  7. Muscarinic receptors, nitric oxide formation and cyclooxygenase pathway involved in tracheal smooth muscle relaxant effect of hydro-ethanolic extract of Lavandula angustifolia flowers.

    Science.gov (United States)

    Naghdi, Farzaneh; Gholamnezhad, Zahra; Boskabady, Mohammad Hossein; Bakhshesh, Morteza

    2018-06-01

    Lavandula angustifolia (L. angustifolia) Mill. (Common name Lavender) is used in traditional and folk medicines for the treatment of various diseases including respiratory disorders worldwide. The relaxant effect of the plant on the smooth muscle of some tissues was shown previously. The present study has investigated the role of different receptors and pathways in the relaxant effect of L. angustifolia on tracheal smooth muscle. Cumulative concentrations of the hydro-ethanolic extract of L. angustifolia flowers (0.5, 1, 2 and 4 mg/ml) were added on pre-contracted tracheal smooth muscle by methacholine (10 μM) or KCl (60 mM) on non-preincubated or preincubated tissues with atropine, chlorpheniramine, propranolol, diltiazem, glibenclamide, indomethacin, ω-nitro-L-arginine methyl ester (L-NAME) and papaverine. The results compared with of theophylline (0.2, 0.4, 0.6 and 0.8 mM) as positive control and saline (1 ml) as negative control. The extract showed concentration-dependent relaxant effects in non-preincubated tracheal smooth muscle contracted by KCl and methacholine (p effect ofL. angustifolia was not significantly different between non-preincubated and preincubated tissues with chlorpheniramine, propranolol, diltiazem, glibenclamide, and papaverine. However, two higher concentrations of L. angustifolia in preincubated tissues with L-NAME (p effects than non-preincubated tissues. The EC 50 values of L. angustifolia in tissues preincubated with indomethacin was significantly higher than non-preincubated trachea (p effects of three first concentrations of the extract on KCl and methacholine-induced muscle contraction were significantly lower than those of theophylline (p effect ofL. angustifolia that was lower than the effect of theophylline. The possible mechanisms of relaxant effect of this plant on tracheal smooth muscle are muscarinic receptors blockade, inhibition of cyclooxygenase pathways and/or involvement of nitric oxide production

  8. Work behaviors of artificial muscle based on cation driven polypyrrole.

    Science.gov (United States)

    Fujisue, Hisashi; Sendai, Tomokazu; Yamato, Kentaro; Takashima, Wataru; Kaneto, Keiichi

    2007-06-01

    A soft actuator mimicking natural muscles (artificial muscle) has been developed using a flexible conducting polymer of polypyrrole films, which were driven by electrical stimulus in a saline solution. The work characteristics were studied under various load stresses and found to behave like natural muscles. The artificial muscles shrunk and stiffened by the positive electrical stimulus by 2-3% at the maximum force of 5 MPa, and relaxed by application of negative voltages. At larger load stresses, the artificial muscle shrunk slowly as natural muscles do. The driving current also lasted longer at larger loads, indicating that the muscle sensed the magnitude of the load stress. During contraction of the muscle, the conversion efficiency from the electrical input and mechanical output energies was estimated to be around 0.06%. The maximum volumetric work was approximately estimated to be 100 kJ m(-3). These figures are unexpectedly small compared with those of natural muscles.

  9. The impact of muscle relaxation techniques on the quality of life of cancer patients, as measured by the FACT-G questionnaire.

    Directory of Open Access Journals (Sweden)

    Paula Parás-Bravo

    Full Text Available Patients with cancer frequently suffer from emotional distress, characterized by psychological symptoms such as anxiety or depression. The presence of psychological symptoms combined with the complex nature of oncology processes can negatively impact patients' quality of life. We aimed to determine the impact of a relaxation protocol on improving quality of life in a sample of oncological patients treated in the Spanish National Public Health System.We conducted a multicenter interventional study without a control group. In total, 272 patients with different oncologic pathologies and showing symptoms of anxiety were recruited from 10 Spanish public hospitals. The intervention comprised abbreviated progressive muscle relaxation training, according to Bernstein and Borkovec. This was followed by weekly telephone calls to each patient over a 1-month period. We collected sociodemographic variables related to the disease process, including information about mental health and the intervention. Patients' quality of life was assessed using the Functional Assessment of Cancer Therapy-General (FACT-G questionnaire. Bivariate and univariate analyses were performed, along with an analysis of multiple correspondences to identify subgroups of patients with similar variations on the FACT-G.Patients showed statistically significant improvements on the FACT-G overall score (W = 16806; p<0.001, with an initial mean score of 55.33±10.42 and a final mean score of 64.49±7.70. We also found significant improvements for all subscales: emotional wellbeing (W = 13118; p<0.001, functional wellbeing (W = 16155.5; p<0.001, physical wellbeing (W = 8885.5; p<0.001, and social and family context (W = -1840; p = 0.037.Patients with cancer who learned and practiced abbreviated progressive muscle relaxation experienced improvement in their perceived quality of life as measured by the FACT-G. Our findings support a previous assumption that complementary techniques (including

  10. New technique using [125I]labeled rose bengal for the quantification in blood samples of pipecuronium bromide, a muscle relaxant drug

    International Nuclear Information System (INIS)

    Schopfer, C.; Benakis, A.; Pittet, J.-F.; Tassonyi, E.

    1991-01-01

    A new technique involving the use of [ 125 I]labeled rose bengal for the quantification of pipecuronium bromide (a muscle relaxant drug) is presented. This technique, which is based on the ability of rose bengal to react with pipecuronium and then form a complex which can be extracted into an organic solvent, involves two steps: the purification and labeling of rose bengal with 125 I, and the quantification of pipecuronium. The specific activity of the compound (106 μCi/mg) allows for the quantification of pipecuronium in biological samples at concentrations as low as 5 ng/ml. (author)

  11. New insights into structure-function relationship of the DHPR beta1a subunit in skeletal muscle excitation-contraction coupling using zebrafish 'relaxed' as an expression system

    International Nuclear Information System (INIS)

    Dayal, A.

    2010-01-01

    The paralyzed zebrafish strain relaxed carries a null mutation for the skeletal muscle dihydropyridine receptor (DHPR) [beta]1a subunit. The lack of [beta]1a not only impedes functional [alpha]1S membrane expression but also precludes the skeletal muscle-specific ultrastructural arrangement of DHPRs into tetrads opposite ryanodine receptor (RyR1), coherent with the absence of skeletal muscle excitation-contraction (EC) coupling. With the plethora of experimental approaches feasible with zebrafish model organism and importantly with the [beta]1-null mutation having a monogenetic inheritance and because of the survival of the relaxed larvae for some days, we were able to establish the zebrafish relaxed as an expression system. Linking in vitro to in vivo observations, a clear differentiation between the major functional roles of [beta] subunits in EC coupling was feasible. The skeletal muscle [beta]1a subunit was able to restore all parameters of EC coupling upon expression in relaxed myotubes and larvae. Expression of the phylogenetically closest isoform to [beta]1a, the cardiac/neuronal [beta]2a subunit or the most distant neuronal [beta]M from the housefly in relaxed myotubes and larvae was likewise able to fully restore [alpha]1S triad targeting and facilitate charge movement. However, efficient tetrad formation and thus intact DHPR-RyR1 coupling was exclusively promoted by the [beta]1a isoform. Consequently, we postulated a model according to which [beta]1a acts as a unique allosteric modifier of [alpha]1S conformation crucial for skeletal muscle EC coupling. Therefore, unique structural elements in [beta]1a must be present which endow it with this exclusive property. Earlier, a unique hydrophobic heptad repeat motif (LVV) in the [beta]1a C-terminus was postulated by others to be essential for skeletal muscle EC coupling. We wanted to address the question if the proposed [beta]1a heptad repeat motif could be an active element of the DHPR-RyR1 signal transduction

  12. Objective measurement of minimal fat in normal skeletal muscles of healthy children using T2 relaxation time mapping (T2 maps) and MR spectroscopy.

    Science.gov (United States)

    Kim, Hee Kyung; Serai, Suraj; Merrow, Arnold C; Wang, Lily; Horn, Paul S; Laor, Tal

    2014-02-01

    Various skeletal muscle diseases result in fatty infiltration, making it important to develop noninvasive biomarkers to objectively measure muscular fat. We compared T2 relaxation time mapping (T2 maps) and magnetic resonance spectroscopy (MRS) with physical characteristics previously correlated with intramuscular fat to validate T2 maps and MRS as objective measures of skeletal muscle fat. We evaluated gluteus maximus muscles in 30 healthy boys (ages 5-19 years) at 3 T with T1-weighted images, T2-W images with fat saturation, T2 maps with and without fat saturation, and MR spectroscopy. We calculated body surface area (BSA), body mass index (BMI) and BMI percentile (BMI %). We performed fat and inflammation grading on T1-W imaging and fat-saturated T2-W imaging, respectively. Mean T2 values from T2 maps with fat saturation were subtracted from T2 maps without fat saturation to determine T2 fat values. We obtained lipid-to-water ratios by MR spectroscopy. Pearson correlation was used to assess relationships between BSA, BMI, BMI %, T2 fat values, and lipid-to-water ratios for each boy. Twenty-four boys completed all exams; 21 showed minimal and 3 showed no fatty infiltration. None showed muscle inflammation. There was correlation between BSA, BMI, and BMI %, and T2 fat values (P values and lipid-to-water ratios (P skeletal muscles, even in microscopic amounts, and validate each other. Both techniques might enable detection of minimal pathological fatty infiltration in children with skeletal muscle disorders.

  13. The effect of progressive muscle relaxation and guided imagery on stress, anxiety, and depression of pregnant women referred to health centers.

    Science.gov (United States)

    Nasiri, Saeideh; Akbari, Hossein; Tagharrobi, Leila; Tabatabaee, Akram Sadat

    2018-01-01

    If anxiety and depression do not detect in pregnant women, they may cause complications for the mother, child, and family, including postpartum depression. With regard to the administrative capability of relaxation in health centers, this study was conducted to determine the effect of progressive muscle relaxation and guided imagery on stress, anxiety, and depression in pregnant women. This randomized clinical trial was conducted on pregnant women in the city of Kashan at 28-36 weeks. At the onset of the study, demographic questionnaire, Edinburgh Depression Scale, and Depression, Anxiety, and Stress Scale-21 (DASS-21) were completed. Providing obtaining score of mild-to-moderate in the stress, anxiety, and depression scale and score of 10 or higher in Edinburgh Depression Scale, individuals were divided randomized to the intervention group ( n = 33) and control group ( n = 33). DASS-21 was again completed in the 4 th -7 th weeks of beginning of the study by all women. Analysis of variance with repeated measures indicated significant differences in mean of scores of stress, anxiety, and depression at three different times in relaxation group ( P pregnancy outcomes.

  14. Design, synthesis and biological evaluation of novel ring-opened cromakalim analogues with relaxant effects on vascular and respiratory smooth muscles and as stimulators of elastin synthesis.

    Science.gov (United States)

    Bouhedja, Mourad; Peres, Basile; Fhayli, Wassim; Ghandour, Zeinab; Boumendjel, Ahcène; Faury, Gilles; Khelili, Smail

    2018-01-20

    Two new series of ring-opened analogues of cromakalim bearing sulfonylurea moieties (series A: with N-unmethylated sulfonylureas, series B: with N-methylated sulfonylureas) were synthesized and tested as relaxants of vascular and respiratory smooth muscles (rat aorta and trachea, respectively). Ex vivo biological evaluations indicated that the most active compounds, belonging to series B, displayed a marked vasorelaxant activity on endothelium-intact aortic rings and the trachea. A majority of series B compounds exhibited a higher vasorelaxant activity (EC 50  stronger relaxant effects on the trachea than the reference compound cromakalim (EC 50  = 124 μM), in particular compounds B4, B7 and B16 (EC 50   57 μM for all, and EC 50  > 200 μM for a majority of them), but some of them showed an interesting relaxing effect on trachea (i.e. A15 and A33, EC 50  = 30 μM). The most potent compounds of both series, i.e. A15, A33 and B16, tested on aortic rings in the presence of glibenclamide or 80 mM KCl, suggested that they acted as voltage-gated Ca 2+ channel blockers, like verapamil, instead of being ATP-potassium channel activators, as is cromakalim, the parent molecule. Further investigations on cultured vascular smooth muscle cells showed a strong stimulating effect on elastin synthesis, especially compound B16, which was more active at 20 μM than diazoxide, a reference ATP-sensitive potassium channel activator. Taken together, our results show that the N-methylation of the sulfonylurea moieties of ring-opened cromakalim analogues led to new compounds blocking calcium-gated channels, which had a major impact on the arterial and tracheal activities as well as selectivity. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  15. Mechanism of action of relaxant effect of Agastache mexicana ssp.mexicana essential oil in guinea-pig trachea smooth muscle.

    Science.gov (United States)

    Navarrete, Andrés; Ávila-Rosas, Natalia; Majín-León, Mateo; Balderas-López, José Luis; Alfaro-Romero, Alejandro; Tavares-Carvalho, José Carlos

    2017-12-01

    Agastache mexicana ssp. mexicana (Kunth) Lint & Epling (Lamiaceae), popularly known as 'toronjil morado', is used in Mexican traditional medicine for the treatment of several diseases such as hypertension, anxiety and respiratory disorders. This study investigates the relaxant action mechanism of A. mexicana ssp. mexicana essential oil (AMEO) in guinea-pig isolated trachea model. AMEO was analyzed by GC/MS. The relaxant effect of AMEO (5-50 μg/mL) was tested in guinea-pig trachea pre-contracted with carbachol (3 × 10  -   6  M) or histamine (3 × 10  -   5  M) in the presence or absence of glibenclamide (10  -   5  M), propranolol (3 × 10  -   6  M) or 2',5'-dideoxyadenosine (10  -   5  M). The antagonist effect of AMEO (10-300 μg/mL) against contractions elicited by carbachol (10  -   15 -10  -   3  M), histamine (10  -   15 -10  -   3  M) or calcium (10-300 μg/mL) was evaluated. Essential oil composition was estragole, d-limonene and linalyl anthranilate. AMEO relaxed the carbachol (EC 50  =   18.25 ± 1.03 μg/mL) and histamine (EC 50  =   13.3 ± 1.02 μg/mL)-induced contractions. The relaxant effect of AMEO was not modified by the presence of propranolol, glibenclamide or 2',5'-dideoxyadenosine, suggesting that effect of AMEO is not related to β 2 -adrenergic receptors, ATP-sensitive potassium channels or adenylate cyclase activation. AMEO was more potent to antagonize histamine (pA 2 ' = -1.507 ± 0.122) than carbachol (pA 2 ' = -2.180 ± 0.357). Also, AMEO antagonized the calcium chloride-induced contractions. The results suggest that relaxant effect of AMEO might be due to blockade of calcium influx in guinea-pig trachea smooth muscle. It is possible that estragole and d-limonene could contribute majority in the relaxant effect of AMEO.

  16. Randomized controlled trial to evaluate the effects of progressive resistance training compared to progressive muscle relaxation in breast cancer patients undergoing adjuvant radiotherapy: the BEST study

    International Nuclear Information System (INIS)

    Potthoff, Karin; Steindorf, Karen; Schmidt, Martina E; Wiskemann, Joachim; Hof, Holger; Klassen, Oliver; Habermann, Nina; Beckhove, Philipp; Debus, Juergen; Ulrich, Cornelia M

    2013-01-01

    Cancer-related fatigue (CRF) is one of the most common and distressing side effects of cancer and its treatment. During and after radiotherapy breast cancer patients often suffer from CRF which frequently impairs quality of life (QoL). Despite the high prevalence of CRF in breast cancer patients and the severe impact on the physical and emotional well-being, effective treatment methods are scarce. Physical activity for breast cancer patients has been reported to decrease fatigue, to improve emotional well-being and to increase physical strength. The pathophysiological and molecular mechanisms of CRF and the molecular-biologic changes induced by exercise, however, are poorly understood. In the BEST trial we aim to assess the effects of resistance training on fatigue, QoL and physical fitness as well as on molecular, immunological and inflammatory changes in breast cancer patients during adjuvant radiotherapy. The BEST study is a prospective randomized, controlled intervention trial investigating the effects of a 12-week supervised progressive resistance training compared to a 12-week supervised muscle relaxation training in 160 patients with breast cancer undergoing adjuvant radiotherapy. To determine the effect of exercise itself beyond potential psychosocial group effects, patients in the control group perform a group-based progressive muscle relaxation training. Main inclusion criterion is histologically confirmed breast cancer stage I-III after lumpectomy or mastectomy with indication for adjuvant radiotherapy. Main exclusion criteria are acute infectious diseases, severe neurological, musculosceletal or cardiorespiratory disorders. The primary endpoint is cancer-related fatigue; secondary endpoints include immunological and inflammatory parameters analyzed in peripheral blood, saliva and urine. In addition, QoL, depression, physical performance and cognitive capacity will be assessed. The BEST study is the first randomized controlled trial comparing progressive

  17. Chronic pain and difficulty in relaxing postural muscles in patients with fibromyalgia and chronic whiplash associated disorders.

    Science.gov (United States)

    Elert, J; Kendall, S A; Larsson, B; Månsson, B; Gerdle, B

    2001-06-01

    To investigate if muscle tension according to the surface electromyogram (EMG) of the shoulder flexors is increased in consecutive patients with fibromyalgia (FM) or chronic whiplash associated disorders (WAD). A total of 59 consecutive patients with FM (n = 36) or chronic WAD (n = 23) performed 100 maximal isokinetic contractions combined with surface electromyography of the trapezius and infraspinatus. A randomized group of pain-free female (n = 27) subjects served as control group. Peak torque initially (Pti) and absolute and relative peak torque at endurance level (PTe, PTer) were registered as output variables, together with the EMG level of unnecessary muscle tension, i.e., the signal amplitude ratio (SAR). The patient groups had a higher level of unnecessary tension initially and at the endurance level. The patients had lower absolute output (PTi and PTe), but the relative levels (PTer) did not differ comparing all 3 groups. Subjects with FM had significantly higher body mass index (BMI) than the other groups. BMI did not influence the SAR but correlated positively with PTi. The results confirmed earlier findings that groups of patients with chronic pain have increased muscle tension and decreased output during dynamic activity compared to pain-free controls. However, the results indicated there is heterogeneity within groups of patients with the same chronic pain disorder and that not all patients with chronic pain have increased muscle tension.

  18. trans-Caryophyllene, a Natural Sesquiterpene, Causes Tracheal Smooth Muscle Relaxation through Blockade of Voltage-Dependent Ca2+ Channels

    Directory of Open Access Journals (Sweden)

    Jader Santos Cruz

    2012-10-01

    Full Text Available trans-Caryophyllene is a major component in the essential oils of various species of medicinal plants used in popular medicine in Brazil. It belongs to the chemical class of the sesquiterpenes and has been the subject of a number of studies. Here, we evaluated the effects of this compound in airway smooth muscle. The biological activities of trans-caryophyllene were examined in isolated bath organs to investigate the effect in basal tonus. Electromechanical and pharmacomechanical couplings were evaluated through the responses to K+ depolarization and exposure to acetylcholine (ACh, respectively. Isolated cells of rat tracheal smooth muscle were used to investigate trans-caryophyllene effects on voltage-dependent Ca2+ channels by using the whole-cell voltage-clamp configuration of the patch-clamp technique. trans-Caryophyllene showed more efficiency in the blockade of electromechanical excitation-contraction coupling while it has only minor inhibitory effect on pharmacomechanical coupling. Epithelium removal does not modify tracheal smooth muscle response elicited by trans-caryophyllene in the pharmacomechanical coupling. Under Ca2+-free conditions, pre-exposure to trans-caryophyllene did not reduce the contraction induced by ACh in isolated rat tracheal smooth muscle, regardless of the presence of intact epithelium. In the whole-cell configuration, trans-caryophyllene (3 mM, inhibited the inward Ba2+ current (IBa to approximately 50% of control levels. Altogether, our results demonstrate that trans-caryophyllene has anti-spasmodic activity on rat tracheal smooth muscle which could be explained, at least in part, by the voltage-dependent Ca2+ channels blockade.

  19. In Vivo Study on Analgesic, Muscle-Relaxant, Sedative Activity of Extracts of Hypochaeris radicata and In Silico Evaluation of Hypochaeris Glucoside and Guaiane-Type Sesquiterpene

    Directory of Open Access Journals (Sweden)

    Tareq Abu-Izneid

    2018-01-01

    Full Text Available Background. Hypochaeris radicata (flatweed from the family Asteraceae is a medicinal plant found in Europe, Middle East, and India. In folkloric medication, it is used to heal jaundice, dyspepsia, constipation, rheumatism, and hypoglycemia as well as renal problems. Leaves and roots of the plant have antioxidant and antibacterial properties. The plant is a rich source of pharmacologically active phytochemicals; however, it is explored scantily. The objective of the current study was to identify the chemical composition and investigate the in vivo biological potency of crude extracts of this plant. Methods. The crude extract and the fractions were screened for various phytochemical groups of constituents following standard procedures. The acute toxicity was assayed for safe range of dose determination. The analgesic potential of the extract and fractions was assessed by acetic acid-induced writhing test. The muscle-relaxant activity was examined by standard inclined-plane test and traction test. Sedative potential of extract/fractions was assessed by using standard white wood procedures. Furthermore, docking analysis of two compounds isolated from the ethyl acetate fraction of the plant was assessed against 3D cyclooxygenase-1 and -2 (COX-1 and COX-2. Results. The extract/fractions of H. radicata showed significant analgesic effect in in vivo model of peripheral algesia. The docking analysis of previously isolated molecules from the plant also exhibited promising interaction with COX-1 and COX-2. Also, the plant has a mild sedative and muscle-relaxant potential. Thus, our study provided pharmacological rationale for the traditional uses of the plant as analgesic and anti-inflammatory remedy. Conclusion. The crude extracts and fractions exhibited excellent activity due to active phytochemicals. These active phytochemicals also exhibited promising interaction with COX-1 and COX-2. This finding directed researcher to isolate active compounds from H

  20. The Effect of Progressive Muscle Relaxation Exercises After Endotracheal Extubation on Vital Signs and Anxiety Level in Open Heart Surgery Patients

    Directory of Open Access Journals (Sweden)

    Özlem İbrahimoğlu

    2017-12-01

    Full Text Available Objective: The purpose of this study was to examine the effects of the exercises of progressive muscle relaxation (PMR on vital signs and anxiety level after endotracheal extubation in open heart surgery. Materials and Methods: This study was carried out as quasi-experimental, pre-test, and post-test with a control group. The study recruited 30 experimental and 30 control group open heart surgery patients, who met the inclusion criteria, from a cardiac and vascular surgery clinic of a university hospital. PMR exercises, which were taught before the surgery, were implemented after the surgery in the intensive care unit simultaneously with endotracheal extubation. The vital signs of the patients were monitored for the first 30 min. The anxiety levels were measured after 30 min of extubation with state anxiety inventory. Results: The lower rates of heartbeat, breathing, arterial blood pressure, and anxiety were observed in the experimental group in all measurements (first 30 min after endotracheal extubation, and the differences were statistically significant in favor of the experimental group (p<0.05. Conclusion: The study showed that the relaxation exercises after endotracheal extubation in open heart surgery patients was effective in improving vital signs and reducing anxiety level.

  1. The effect of timing of intravenous muscle relaxant on the quality of double-contrast barium enema

    International Nuclear Information System (INIS)

    Elson, E.M.; Elson, E.M.; Campbell, D.M.; Halligan, S.; Shaikh, I.; Davitt, S.; Bartram, C.I.

    2000-01-01

    AIM: To determine whether the timing of buscopan administration during double-contrast barium enema examination (DCBE) affects diagnostic quality. MATERIALS AND METHODS: In a prospective setting, 100 consecutive adult out-patients referred for DCBE received 20 mg buscopan (hyoscine-N-butylbromide) intravenously, either before infusion of barium suspension (Group A) or after barium infusion and gas insufflation (Group B). A subjective assessment of ease of contrast medium infusion was made at the time of examination and the films subsequently analysed by two radiologists unaware of the mode of relaxant administration, who noted the quality of mucosal coating and made subjective and objective measurements of segmental distension. RESULTS: There was no significant difference in screening times, infusion difficulty or colonic contrast medium coating between the two groups. Subjective assessment of distension of the caecum, ascending colon, transverse colon and rectum were not significantly different. Patients receiving intravenous relaxant after barium and gas infusion had less subjective descending (P = 0.05) and sigmoid (P = 0.04) colon distension, but there was no significant difference with respect to maximal bowel diameter in any of the segments measured. CONCLUSION: The timing of intravenous administration during DCBE is likely to have no significant effect on the diagnostic quality of the study. Elson, E.M. (2000)

  2. A clinical randomized controlled trial of music therapy and progressive muscle relaxation training in female breast cancer patients after radical mastectomy: results on depression, anxiety and length of hospital stay.

    Science.gov (United States)

    Zhou, Kaina; Li, Xiaomei; Li, Jin; Liu, Miao; Dang, Shaonong; Wang, Duolao; Xin, Xia

    2015-02-01

    To examine effects of music therapy and progressive muscle relaxation training on depression, anxiety and length of hospital stay in Chinese female breast cancer patients after radical mastectomy. A total of 170 patients were randomly allocated to the intervention group (n = 85) receiving music therapy and progressive muscle relaxation training plus routine nursing care and the control group (n = 85) receiving routine nursing care. Music therapy and progressive muscle relaxation training were performed twice a day within 48 h after radical mastectomy, once in the early morning (6a.m.-8a.m.) and once in the evening (9p.m.-11p.m.), for 30 min per session until discharged from the hospital. A general linear model with univariate analysis showed that the intervention group patients had significant improvement in depression and anxiety in the effects of group (F = 20.31, P Music therapy and progressive muscle relaxation training can reduce depression, anxiety and length of hospital stay in female breast cancer patients after radical mastectomy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Evaluating the Effectiveness of Using a Progressive Muscle Relaxation Technique on the Self-Efficacy of Breastfeeding in Mothers With Preterm Infants.

    Science.gov (United States)

    Karbandi, Soheila; Hosseini, Seyedeh Maryam; Hosseini, Seyedeh Asieh; Sadeghi, Farshad; Hesari, Maryam; Masoudi, Reza

    2017-08-01

    Breast milk is a God-given gift that conveys a mother's love and compassion and that is made according to the needs and age of the child. Mothers who are interested in the welfare of their newborns tend to breastfeed their children. Training programs have been shown to improve breastfeeding self-efficacy in terms of both duration and amount. The aim of this study was to evaluate the effect of using the progressive muscle relaxation (PMR) technique on the self-efficacy of breastfeeding in mothers with preterm infants. A clinical trial approach was used. Sixty mothers with preterm infants were randomly assigned to either the intervention or control group. The clinical trial ran for a period of 2 months for both groups. At 24-72 hours postpartum, the researcher used the Jacobson method to provide 30-45 minutes of individual training to the intervention group participants on PMR. Under the Jacobson method, mothers contract the 16 groups of muscles until they experience the feeling of pressure and then relax these muscles. The tools used in this study were the standard questionnaire of Dennis breastfeeding self-efficacy, which was completed by the participants at baseline, at the end of the fourth week, and during the eighth week. Data were analyzed using SPSS software. No significant difference was observed between the intervention and control groups in terms of demographic variables (p > .05). Independent t tests found no significant difference between the two groups (p = .45) in terms of mean score of maternal breastfeeding self-efficacy at pretest and significantly higher scores for the intervention group than the control group at both 4 (p = .001) and 8 (p mothers with preterm infants, training and performing these exercises as an effective and low-cost method to improve the health of mothers, particularly mothers of preterm infants, are recommended. The PMR technique facilitates the self-efficacy of breastfeeding in mothers with preterm infants and should be

  4. High-throughput and simultaneous analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry in the positive and negative ionization modes.

    Science.gov (United States)

    Ogawa, Tadashi; Hattori, Hideki; Kaneko, Rina; Ito, Kenjiro; Iwai, Masae; Mizutani, Yoko; Arinobu, Tetsuya; Ishii, Akira; Seno, Hiroshi

    2011-06-01

    In this report, a high-throughput and sensitive method for analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in the positive and negative ionization modes using tolbutamide as internal standard is presented. After pretreatment of a plasma sample by solid-phase extraction with an Oasis HLB cartridge, muscle relaxants were analyzed by UPLC with Acquity UPLC BEH C(18) column and Acquity TQD tandem quadrupole mass spectrometer equipped with an electrospray ionization interface. The calibration curves for muscle relaxants spiked into human plasma equally showed good linearities in the nanogram per milliliter order range. The detection limits (signal-to-noise ratio = 3) was as low as 0.1-2 ng/mL. The method gave satisfactory recovery rates, accuracy, and precision for quality control samples spiked with muscle relaxants. To further validate the present method, 250 mg of chlorphenesin carbamate was orally administered to a healthy male volunteer, and the concentrations of chlorphenesin carbamate in plasma were measured 0.5, 1, 2, 4, 6, and 8 h after dosing; their concentrations in human plasma were between 0.62 and 2.44 μg/mL. To our knowledge, this is the first report describing simultaneous analysis of over more than two central-acting muscle relaxants by liquid chromatography-tandem mass spectrometry. This has been realized by the capability of our instrument for simultaneous multiple reaction monitoring of the target compounds in both positive and negative ionization modes. Therefore, the present method seems very useful in forensic and clinical toxicology and pharmacokinetic studies.

  5. Relaxation Techniques to Manage IBS Symptoms

    Science.gov (United States)

    ... for 15–20 seconds and then begin again. Progressive Muscle Relaxation This method of relaxation focuses on ... helpful, please consider supporting IFFGD with a small tax- deductible donation. Make Donation Adapted from IFFGD Publication # ...

  6. Relaxation Responses of Trigonal Smooth Muscle from Rabbit by Alpha1-Adrenoceptor Antagonists Alfuzosin, Doxazosin and Tamsulosin

    Directory of Open Access Journals (Sweden)

    A. Karadeniz

    2008-01-01

    Full Text Available This study was performed to investigate the effects of alfuzosin, doxazosin and tamsulosin in vitro on trigone smooth muscle of rabbit. In this study, fifteen rabbits weighing 2.5 - 3 kg were used. One strip in the shape of a trigone was prepared for each of the isolated bladders. Firstly, an initial tension of 1 g was placed on each segment, and we waited for equilibration by constantly bubbling with 95% O2 and 5% CO2. Next, the determination level of electrical stimulation which created submaximal contraction and effective dosage were found for trigone and they were determined by applying different concentrations of phenylephrine (10-8 M, 10-7 M, 10-6 M, 10-5 M, respectively. Firstly 10-8 M dosage of alfuzosin (10-8 M, 10-7 M, 10-6 M, 10-5 M was added, then we waited for 20 min. Then, an effective dosage of phenylephrine (10-5 M was added into the solution and we waited for 7 min again. After this process, electrical stimulation was applied for the contraction of the tissue. After stimulation, the tissue was washed twice every two minutes and rested; we waited until the tissue reached its starting stretching value. The same processes were performed for the other dosages of alfuzosin (10-7 M, 10-6 M, 10-5 M, doxazosin (10-7 M, 10-6 M, 10-5 M and tamsulosin (10-7 M, 10-6 M, 10-5 M, respectively. In conclusion, when we compared the amplitudes of the responses of all concentrations of doxazosin, alfuzosin and tamsulosin in the trigone smooth muscle with amplitude of a response of effective concentration of phenylephrine, it was determined that the prevention level of contractions occurred after tamsulosin hydrochloride was higher than after alfuzosin hydrochloride and doxazosin mesylate. With these results, we showed that alfuzosin, doxazosin and tamsulosin inhibited noradrenalin-based contractions in the rabbit trigone smooth muscle and this result can be used both for in vitro and in vivo future studies.

  7. The effect of improvisation-assisted desensitization, and music-assisted progressive muscle relaxation and imagery on reducing pianists' music performance anxiety.

    Science.gov (United States)

    Kim, Youngshin

    2008-01-01

    The purpose of this study was to investigate the effects of two music therapy approaches, improvisation-assisted desensitization, and music-assisted progressive muscle relaxation and imagery on ameliorating the symptoms of music performance anxiety (MPA) among student pianists. Thirty female college pianists (N = 30) were randomly assigned to one of two conditions: (a) improvised music-assisted desensitization group (n = 15), or (b) music-assisted progressive muscle relaxation (PMR) and imagery group (n = 15). All participants received 6 weekly music therapy sessions according to their assigned group. Two lab performances were provided; one before and one after the 6 music therapy sessions, as the performance stimuli for MPA. All participants completed pretest and posttest measures that included four types of visual analogue scales (MPA, stress, tension, and comfort), the state portion of Spielberger's State-Trait Anxiety Inventory (STAI), and the Music Performance Anxiety Questionnaire (MPAQ) developed by Lehrer, Goldman, and Strommen (1990). Participants' finger temperatures were also measured. When results of the music-assisted PMR and imagery condition were compared from pretest to posttest, statistically significant differences occurred in 6 out of the 7 measures-MPA, tension, comfort, STAI, MPAQ, and finger temperature, indicating that the music-assisted PMR and imagery treatment was very successful in reducing MPA. For the improvisation-assisted desensitization condition, the statistically significant decreases in tension and STAI, with increases in finger temperature indicated that this approach was effective in managing MPA to some extent. When the difference scores for the two approaches were compared, there was no statistically significant difference between the two approaches for any of the seven measures. Therefore, no one treatment condition appeared more effective than the other. Although statistically significant differences were not found between

  8. The Effort to Reduce a Muscle Fatigue Through Gymnastics Relaxation and Ergonomic Approach for Computer Users in Central Building State University of Medan

    Science.gov (United States)

    Gultom, Syamsul; Darma Sitepu, Indra; Hasibuan, Nurman

    2018-03-01

    Fatigue due to long and continuous computer usage can lead to problems of dominant fatigue associated with decreased performance and work motivation. Specific targets in the first phase have been achieved in this research such as: (1) Identified complaints on workers using computers, using the Bourdon Wiersma test kit. (2) Finding the right relaxation & work posture draft for a solution to reduce muscle fatigue in computer-based workers. The type of research used in this study is research and development method which aims to produce the products or refine existing products. The final product is a prototype of back-holder, monitoring filter and arranging a relaxation exercise as well as the manual book how to do this while in front of the computer to lower the fatigue level for computer users in Unimed’s Administration Center. In the first phase, observations and interviews have been conducted and identified the level of fatigue on the employees of computer users at Uniemd’s Administration Center using Bourdon Wiersma test and has obtained the following results: (1) The average velocity time of respondents in BAUK, BAAK and BAPSI after working with the value of interpretation of the speed obtained value of 8.4, WS 13 was in a good enough category, (2) The average of accuracy of respondents in BAUK, in BAAK and in BAPSI after working with interpretation value accuracy obtained Value of 5.5, WS 8 was in doubt-category. This result shows that computer users experienced a significant tiredness at the Unimed Administration Center, (3) the consistency of the average of the result in measuring tiredness level on computer users in Unimed’s Administration Center after working with values in consistency of interpretation obtained Value of 5.5 with WS 8 was put in a doubt-category, which means computer user in The Unimed Administration Center suffered an extreme fatigue. In phase II, based on the results of the first phase in this research, the researcher offers

  9. Relaxation-compensated CEST-MRI at 7 T for mapping of creatine content and pH--preliminary application in human muscle tissue in vivo.

    Science.gov (United States)

    Rerich, Eugenia; Zaiss, Moritz; Korzowski, Andreas; Ladd, Mark E; Bachert, Peter

    2015-11-01

    The small biomolecule creatine is involved in energy metabolism. Mapping of the total creatine (mostly PCr and Cr) in vivo has been done with chemical shift imaging. Chemical exchange saturation transfer (CEST) allows an alternative detection of creatine via water MRI. Living tissue exhibits CEST effects from different small metabolites, including creatine, with four exchanging protons of its guanidinium group resonating about 2 ppm from the water peak and hence contributing to the amine proton CEST peak. The intermediate exchange rate (≈ 1000 Hz) of the guanidinium protons requires high RF saturation amplitude B1. However, strong B1 fields also label semi-solid magnetization transfer (MT) effects originating from immobile protons with broad linewidths (~kHz) in the tissue. Recently, it was shown that endogenous CEST contrasts are strongly affected by the MT background as well as by T1 relaxation of the water protons. We show that this influence can be corrected in the acquired CEST data by an inverse metric that yields the apparent exchange-dependent relaxation (AREX). AREX has some useful linearity features that enable preparation of both concentration, and--by using the AREX-ratio of two RF irradiation amplitudes B1--purely exchange-rate-weighted CEST contrasts. These two methods could be verified in phantom experiments with different concentration and pH values, but also varying water relaxation properties. Finally, results from a preliminary application to in vivo CEST imaging data of the human calf muscle before and after exercise are presented. The creatine concentration increases during exercise as expected and as confirmed by (31)P NMR spectroscopic imaging. However, the estimated concentrations obtained by our method were higher than the literature values: cCr,rest=24.5±3.74mM to cCr,ex=38.32±13.05mM. The CEST-based pH method shows a pH decrease during exercise, whereas a slight increase was observed by (31)P NMR spectroscopy. Copyright © 2015

  10. 31P and 1H NMR studies of the structure of enzyme-bound substrate complexes of lobster muscle arginine kinase: Relaxation measurements with Mn(II) and Co(II)

    International Nuclear Information System (INIS)

    Jarori, G.K.; Ray, B.D.; Rao, B.D.N.

    1989-01-01

    The paramagnetic effects of Mn(II) and Co(II) on the spin-lattice relaxation rates of 31 P nuclei of ATP and ADP and of Mn(II) on the spin-lattice relaxation rate of the δ protons of arginine bound to arginine kinase from lobster tail muscle have been measured. Temperature variation of 31 P relaxation rates in E-MnADP and E-MnATP yields activation energies (ΔE) in the range 6-10 kcal/mol. Thus, the 31 P relaxation rates in these complexes are exchange limited and cannot provide structural information. However, the relaxation rates in E-CoADP and E-CoATP exhibit frequency dependence and ΔE values in the range 1-2 kcal/mol; i.e., these rates depend upon 31 P-Co(II) distances. These distances were calculated to be in the range 3.2-4.5 angstrom, appropriate for direct coordination between Co(II) and the phosphoryl groups. The paramagnetic effect of Mn(II) on the 1 H spin-lattice relaxation rate of the δ protons of arginine in the E-MnADP-Arg complex was also measured at three frequencies. From the frequency dependence of the relaxation rate an effective τ C of 0.6 ns has also been calculated, which is most likely to be the electron spin relaxation rate (τ S1 ) for Mn(II) in this complex. The distance estimated on the basis of the reciprocal sixth root of the average relaxation rate of the δ protons was 10.9 ± 0.3 angstrom

  11. Peptide IC-20, encoded by skin kininogen-1 of the European yellow-bellied toad, Bombina variegata, antagonizes bradykinin-induced arterial smooth muscle relaxation

    Directory of Open Access Journals (Sweden)

    Mu Yang

    2011-01-01

    Full Text Available Objectives: The objectives were to determine if the skin secretion of the European yellow-bellied toad (Bombina variegata, in common with other related species, contains a bradykinin inhibitor peptide and to isolate and structurally characterize this peptide. Materials and Methods: Lyophilized skin secretion obtained from this toad was subjected to reverse phase HPLC fractionation with subsequent bioassay of fractions for antagonism of the bradykinin activity using an isolated rat tail artery smooth muscle preparation. Subsequently, the primary structure of the peptide was established by a combination of microsequencing, mass spectroscopy, and molecular cloning, following which a synthetic replicate was chemically synthesised for bioassay. Results: A single peptide of molecular mass 2300.92 Da was resolved in HPLC fractions of skin secretion and its primary structure determined as IYNAIWP-KH-NK-KPGLL-. Database interrogation with this sequence indicated that this peptide was encoded by skin kininogen-1 previously cloned from B. variegata. The blank cycles were occupied by cysteinyl (C residues and the peptide was located toward the C-terminus of the skin kininogen, and flanked N-terminally by a classical -KR- propeptide convertase processing site. The peptide was named IC-20 in accordance (I = N-terminal isoleucine, C = C-terminal cysteine, 20 = number of residues. Like the natural peptide, its synthetic replicate displayed an antagonism of bradykinin-induced arterial smooth muscle relaxation. Conclusion: IC-20 represents a novel bradykinin antagonizing peptide from amphibian skin secretions and is the third such peptide found to be co-encoded with bradykinins within skin kininogens.

  12. In vitro and in vivo aphrodisiac properties of the seed extract from Allium tuberosum on corpus cavernosum smooth muscle relaxation and sexual behavior parameters in male Wistar rats.

    Science.gov (United States)

    Tang, Xingli; Olatunji, Opeyemi J; Zhou, Yifeng; Hou, Xilin

    2017-12-01

    Allium tuberosum is a well-known spice as well as a herb in traditional Chinese medicine, used for increasing libido and treating erectile dysfunction. However, not many studies have been done to evaluate the sexual enhancing properties of A. tuberosum. The aim of this study was to evaluate the aphrodisiac and vasorelaxant properties of A. tuberosum on corpus cavernosum smooth muscle (CCSM) as well as checking the effect on enhancing male rat sexual behavior, libido, potency as well as its spermatogenic properties. The seeds were powdered and sequentially extracted with hexane, ethyl acetate and butanol. Male Wistar rats were administered with graded doses of the n-BuOH extracts (ATB) of A. tuberosum (50, 100, 200 and 400 mg/kg) and Viagra was used as the positive control drug. The extract/drug was administered by gastric probe once daily for 45 days and the sexual behavior was analyzed by exposing the male rats to female rats in the estrus period. ATB relaxed corpus cavernosum smooth muscle (68.9%) at a concentration of 200 μg/ml. The results obtained from the animal studies indicated that ATB significantly increased mount frequency (MF), intromission frequency (IF), ejaculation frequency (EF), ejaculation latency (EL) and markedly reduced post ejaculatory interval (PEI), mount latency (ML), and intromission latency (IL). Furthermore, a remarkable increase in the test for potency was observed as witnessed by marked increase in erections, quick flips, long flips and total reflex. In addition, ATB significantly improved the sperm viability and count as well as increased the concentrations of testosterone, follicle stimulating hormone (FSH), and phosphatases in the treated animals. Thus our results suggest that A. tuberosum could stimulate sexual arousal and enhance sexual execution in male rats, thus providing valuable experimental evidence that A. tuberosum possesses sexual enhancing properties.

  13. Culturally adapted CBT (CA-CBT) for Latino women with treatment-resistant PTSD: a pilot study comparing CA-CBT to applied muscle relaxation.

    Science.gov (United States)

    Hinton, Devon E; Hofmann, Stefan G; Rivera, Edwin; Otto, Michael W; Pollack, Mark H

    2011-04-01

    We examined the therapeutic efficacy of a culturally adapted form of CBT (CA-CBT) for PTSD as compared to applied muscle relaxation (AMR) for female Latino patients with treatment-resistant PTSD. Participants were randomized to receive either CA-CBT (n = 12) or AMR (n = 12), and were assessed before treatment, after treatment, and at a 12-week follow-up. The treatments were manualized and delivered in the form of group therapy across 14 weekly sessions. Assessments included a measure of PTSD, anxiety, culturally relevant idioms of distress (nervios and ataque de nervios), and emotion regulation ability. Patients receiving CA-CBT improved significantly more than in the AMR condition. Effect size estimates showed very large reductions in PTSD symptoms from pretreatment to posttreatment in the CA-CBT group (Cohen's d = 2.6) but only modest improvements in the AMR group (0.8). These results suggest that CA-CBT can be beneficial for previously treatment-resistant PTSD in Latino women. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. A Randomized Controlled Trial for the Effectiveness of Progressive Muscle Relaxation and Guided Imagery as Anxiety Reducing Interventions in Breast and Prostate Cancer Patients Undergoing Chemotherapy

    Directory of Open Access Journals (Sweden)

    Andreas Charalambous

    2015-01-01

    Full Text Available Objective. To test the effectiveness of guided imagery (GI and progressive muscle relaxation (PMR as stress reducing interventions in patients with prostate and breast cancer who undergo chemotherapy. Methods. Patients were randomly assigned to either the control group or the intervention group (PMR and GI. Patients were observed for a total duration of 3 weeks and assessed with the SAS and BECK-II questionnaires for anxiety and depression, respectively, in addiotion to two biological markers (saliva cortisol and saliva amylase (trial registration number: NCT01275872. Results. 256 patients were registered and 236 were randomly assigned. In total 104 were randomised to the control group and 104 to the intervention group. Intervention’s mean anxiety score and depression score changes were significantly different compared to the control’s (b=-29.4, p<0.001; b=-29.4, p<0.001, resp.. Intervention group’s cortisol levels before the intervention (0.30±0.25 gradually decreased up to week 3 (0.16±0.18, whilst the control group’s cortisol levels before the intervention (0.21±0.22 gradually increased up to week 3 (0.44±0.35. The same interaction appears for the Amylase levels (p<0.001. Conclusions. The findings showed that patients with prostate and breast cancer undergoing chemotherapy treatment can benefit from PMR and GI sessions to reduce their anxiety and depression.

  15. Changes in Sensory Responsiveness in Behaving Primates.

    Science.gov (United States)

    1986-07-14

    controlled behavioral training and monitoring, and electrophysiological recording in awake , behaving monkeys. All I, research equipment listed in the original...recording from the sensorimotor cortices was conducted on May 21. Under general anesthesia, a craniotomy was performed over the pre- and postcentral cortices...Department of Neurosurgery at U.T. Dr. Klein is somewhat unusual in that he has had previous experience recording from awake , behaving monkeys. The experience

  16. METODE ACTIVE ISOLATED STRETCHING (AIS DAN METODE HOLD RELAX STRETCHING (HRS SAMA EFEKTIF DALAM MENINGKATKAN FLEKSIBILITAS OTOT HAMSTRING PADA MAHASISWA AKADEMI FISIOTERAPI WIDYA HUSADA SEMARANG YANG MENGALAMI HAMSTRING MUSCLE TIGHTNESS (HMTs

    Directory of Open Access Journals (Sweden)

    Akhmad alfajri

    2015-08-01

    Full Text Available Students with Hamstring Muscle Tightness (HMTs will be at risk of Anterior Crusiatum Ligament (ACL, Low Back Pain (LBP and also Plantar Faciitis. One of the efforts to reduce tightness and improve hamstring muscle flexibility is stretching. Active Isolated Stretching (AIS and Hold Relax Stretching (HRS are the methods of influential stretching to improve muscle flexibility. The goal of the research is to prove that AIS method is equally effective with the HRS method to improve hamstring muscle flexibility to the HMTs patients. The research method was true experimental with pre and post test group design. The research was conducted for 3 weeks and the samples are 23 students in range of 18-25 years old students of physical therapy in Physical Therapy Academy of Widya Husada Semarang which divided into 2 groups; AIS group (n= 12 and HRS group (n= 11. The research used Sit and Reach Test (SRT as the measurement instrument. The result of the research was the average result of AIS group used SRT before treatment was 1.75 cm, SB= 4.309 and after treatment was 10. 58 cm, SB = 8. 005 within p= 0.000 (p 0.05. Those explain that the improvement of hamstring muscle flexibility to the two groups does not show any significant difference. Conclusion from this study was active isolated stretching method and hold relax stretching method are equally effective to improving muscle flexibility of hamstring muscle tightness students of physical therapy in Physical Therapy Academy of Widya Husada Semarang.

  17. Responsiveness in Behaving Monkeys and Human Subjects

    Science.gov (United States)

    1993-07-31

    Status of Current Research - Statement of Work Each study involving awake , behaving monkey neurophysiological recording used a behavioral paradigm that...anesthesia. A craniotomy was performed at approximately A+ 14.5mm. The recording chamber then was fixed to the skull at a lateral angle of 8’ from

  18. Pituitary adenylate cyclase activating polypeptide induces vascular relaxation and inhibits non-vascular smooth muscle activity in the rabbit female genital tract

    DEFF Research Database (Denmark)

    Steenstrup, B R; Ottesen, B; Jørgensen, M

    1994-01-01

    In vitro effects of two bioactive forms of pituitary adenylate cyclase activating polypeptide (PACAP): PACAP-38 and PACAP-27 were studied on rabbit vascular and non-vascular smooth muscle. Segments of the ovarian artery and muscle strips from the fallopian tube were used. Two series of experiment...

  19. Review of Theoretical Prediction Models for Organic Extract Metabolites, Effect of Drying Temperature on Smooth Muscle Relaxing Activity Induced by Organic Extracts Specially Cecropia Obtusifolia Portal and Web Server Predictors of Drug-Protein Interaction.

    Science.gov (United States)

    Aguirre-Crespo, Francisco; García-Mera, Xerardo; Guillén-Poot, Mónica Anahi; May-Díaz, Héctor Fernado; Tun-Suárez, Adrián; Aguirre-Crespo, A; Hernández-Rodríguez, J; Vergara-Galicia, Jorge; Rodríguez-López, V; Prado-Prado, Francisco J

    2015-02-19

    Cecropia obtusifolia bertol is medicinal specie used in the treatment of diabetes mellitus and hypertension and it has scientific studies that support the traditional use. However, it is required to understand the influence of drying temperature on the yield and pharmacological activity. Drying rate, extraction efficiency, changes in the UV-Vis spectrum and estimating chlorophylls were stimulated with the increasing temperature. Finally, relaxant activity of vascular smooth muscle is increased by 70ºC and reducing ability by the method of CARF increases with temperature. Analytical studies are required to identify changes in the metabolic content and those that ensure the safety and efficacy for human consumption. In this sense, bioinformatic studies may be helpful. Studies such as QSAR can help us to study these metabolites derived from natural products. MIND-BETS model and NL MIND-BETS model to predict DPIs was introduced using MARCH-INSIDE (MI) software to calculate structural parameters for drugs and enzymes respectively. We firstly revised the state-of-art on the design with review of previous works with hypertension activity based on theoretical studies. A study, evaluating the effect of drying temperature of leaves of C. obtusifolia on the relaxing of vascular smooth muscle, antioxidant activity and the presence of chlorophylls, with a focus on Cecropia metabolites. Last, we carried out QSAR studies using MIND-BEST and NL MIND-BEST web servers in order to understand the essential metabolites structural requirement for binding with receptors for FDA proteins.

  20. Anxiety and Anger Symptoms in Hwabyung Patients Improved More following 4 Weeks of the Emotional Freedom Technique Program Compared to the Progressive Muscle Relaxation Program: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Jin Woo Suh

    2015-01-01

    Full Text Available Background. The Emotional Freedom Technique (EFT is a meridian-based psychological therapy. The present clinical trial investigates the effectiveness of EFT as a new treatment option for Hwabyung (HB patients experiencing anger and compares the efficacy to the Progressive Muscle Relaxation (PMR, the conventional meditation technique. Methods. The EFT and progressive muscle relaxation (PMR methods were performed on 27 HB patients, and their capacities to alleviate anxiety, anger, and emotional status were compared. After a 4-week program, a survey was conducted; patients then completed a self-training program for 4 weeks, followed by a second survey. Results. During the initial 4 weeks, the EFT group experienced a significant decrease in the HB symptom scale, anger state, and paranoia ideation (p<0.05. Over the entire 9-week interval, there were significant decreases in the HB symptom scale, anxiety state, anger state, anger trait, somatization, anxiety, hostility, and so on in EFT group (p<0.05. Conclusion. The EFT group showed improved psychological symptoms and physical symptoms greater than those observed in the PMR group. EFT more effectively alleviated HB symptoms compared to PMR. EFT group showed better maintenance during self-training, suggesting good model of self-control treatment in HB patients.

  1. The effect of progressive muscle relaxation and guided imagery on stress, anxiety, and depression of pregnant women referred to health centers

    Directory of Open Access Journals (Sweden)

    Saeideh Nasiri

    2018-01-01

    Conclusions: In this study, relaxation could reduce stress, anxiety, and depression in pregnant women during six sessions. Due to the simplicity and low cost of this technique, it can be used to reduce stress and anxiety in pregnant women and improve pregnancy outcomes.

  2. Relaxation System

    Science.gov (United States)

    1987-01-01

    Environ Corporation's relaxation system is built around a body lounge, a kind of super easy chair that incorporates sensory devices. Computer controlled enclosure provides filtered ionized air to create a feeling of invigoration, enhanced by mood changing aromas. Occupant is also surrounded by multidimensional audio and the lighting is programmed to change colors, patterns, and intensity periodically. These and other sensory stimulators are designed to provide an environment in which the learning process is stimulated, because research has proven that while an individual is in a deep state of relaxation, the mind is more receptive to new information.

  3. Laser flash photolysis of diazo-2, a caged calcium chelator: The relationship between the extent and rate of smooth muscle relaxation

    Czech Academy of Sciences Publication Activity Database

    Pelc, Radek; Ishii, N.; Ashley, C. C.

    2009-01-01

    Roč. 21, č. 1 (2009), s. 32-38 ISSN 1042-346X R&D Projects: GA MŠk(CZ) LC06063 Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z50200510 Keywords : caged calcium chelator * smooth muscle * blood pressure Subject RIV: ED - Physiology Impact factor: 0.652, year: 2009

  4. Quantitative Skeletal Muscle MRI: Part 2, MR Spectroscopy and T2 Relaxation Time Mapping-Comparison Between Boys With Duchenne Muscular Dystrophy and Healthy Boys.

    Science.gov (United States)

    Kim, Hee Kyung; Serai, Suraj; Lindquist, Diana; Merrow, Arnold C; Horn, Paul S; Kim, Dong Hoon; Wong, Brenda L

    2015-08-01

    The purpose of this study is to validate the use of MR spectroscopy (MRS) in measuring muscular fat and to compare it with T2 maps in differentiating boys with Duchenne muscular dystrophy (DMD) from healthy boys. Forty-two boys with DMD and 31 healthy boys were evaluated with MRI with (1)H-MRS and T2 maps. Grading of muscle fat and edema on conventional images, calculation of fat fractions ([fat / fat] + water) on MRS, and calculation of T2 fat values on T2 maps of the gluteus maximus and vastus lateralis muscles were performed. Group comparisons were made. The 95% reference interval (RI) of fat fraction for the control group was applied and compared with T2 map results. Minimal fat on T1-weighted images was seen in 90.3% (gluteus maximus) and 71.0% (vastus lateralis) of healthy boys, versus 33.3% (gluteus maximus) and 52.4% (vastus lateralis) of boys with DMD. Muscle edema was seen in none of the healthy boys versus 52.4% (gluteus maximus) and 57.1% (vastus lateralis) of the boys with DMD. Fat fractions were higher in the DMD group (52.7%, gluteus maximus; 27.3%, vastus lateralis) than in the control group (12.8%, gluteus maximus; 13.7%, vastus lateralis) (p muscle edema in DMD.

  5. The relationships between suggestibility, influenceability, and relaxability.

    Science.gov (United States)

    Polczyk, Romuald; Frey, Olga; Szpitalak, Malwina

    2013-01-01

    This research explores the relationships between relaxability and various aspects of suggestibility and influenceability. The Jacobson Progressive Muscle Relaxation procedure was used to induce relaxation. Tests of direct suggestibility, relating to the susceptibility of overt suggestions, and indirect suggestibility, referring to indirect hidden influence, as well as self-description questionnaires on suggestibility and the tendency to comply were used. Thayer's Activation-Deactivation Adjective Check List, measuring various kinds of activation and used as a pre- and posttest, determined the efficacy of the relaxation procedure. Indirect, direct, and self-measured suggestibility proved to be positively related to the ability to relax, measured by Thayer's subscales relating to emotions. Compliance was not related to relaxability. The results are discussed in terms of the aspects of relaxation training connected with suggestibility.

  6. Sleep, Stress & Relaxation: Rejuvenate Body & Mind

    Science.gov (United States)

    Sleep, Stress & Relaxation: Rejuvenate Body & Mind; Relieve Stress; best ways to relieve stress; best way to relieve stress; different ways to relieve stress; does smoking relieve stress; does tobacco relieve stress; how can I relieve stress; how can you relieve stress; how do I relieve stress; reduce stress; does smoking reduce stress; how can I reduce stress; how to reduce stress; reduce stress; reduce stress levels; reducing stress; smoking reduce stress; smoking reduces stress; stress reducing techniques; techniques to reduce stress; stress relief; best stress relief; natural stress relief; need stress relief; relief for stress; relief from stress; relief of stress; smoking and stress relief; smoking for stress relief; smoking stress relief; deal with stress; dealing with stress; dealing with anger; dealing with stress; different ways of dealing with stress; help dealing with stress; how to deal with anger; how to deal with stress; how to deal with stress when quitting smoking; stress management; free stress management; how can you manage stress; how do you manage stress; how to manage stress; manage stress; management of stress; management stress; managing stress; strategies for managing stress; coping with stress; cope with stress; copeing with stress; coping and stress; coping skills for stress; coping strategies for stress; coping strategies with stress; coping strategy for stress; coping with stress; coping with stress and anxiety; emotional health; emotional health; emotional health article; emotional health articles; deep relaxation; deep breathing relaxation techniques; deep muscle relaxation; deep relaxation; deep relaxation meditation; deep relaxation technique; deep relaxation techniques; meditation exercises; mindful exercises; mindful meditation exercises; online relaxation exercises; relaxation breathing exercises; relaxation exercise; relaxation exercises; stress relaxation; methods of relaxation for stress; relax stress; relax techniques stress

  7. Ionic liquids behave as dilute electrolyte solutions

    Science.gov (United States)

    Gebbie, Matthew A.; Valtiner, Markus; Banquy, Xavier; Fox, Eric T.; Henderson, Wesley A.; Israelachvili, Jacob N.

    2013-01-01

    We combine direct surface force measurements with thermodynamic arguments to demonstrate that pure ionic liquids are expected to behave as dilute weak electrolyte solutions, with typical effective dissociated ion concentrations of less than 0.1% at room temperature. We performed equilibrium force–distance measurements across the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) using a surface forces apparatus with in situ electrochemical control and quantitatively modeled these measurements using the van der Waals and electrostatic double-layer forces of the Derjaguin–Landau–Verwey–Overbeek theory with an additive repulsive steric (entropic) ion–surface binding force. Our results indicate that ionic liquids screen charged surfaces through the formation of both bound (Stern) and diffuse electric double layers, where the diffuse double layer is comprised of effectively dissociated ionic liquid ions. Additionally, we used the energetics of thermally dissociating ions in a dielectric medium to quantitatively predict the equilibrium for the effective dissociation reaction of [C4mim][NTf2] ions, in excellent agreement with the measured Debye length. Our results clearly demonstrate that, outside of the bound double layer, most of the ions in [C4mim][NTf2] are not effectively dissociated and thus do not contribute to electrostatic screening. We also provide a general, molecular-scale framework for designing ionic liquids with significantly increased dissociated charge densities via judiciously balancing ion pair interactions with bulk dielectric properties. Our results clear up several inconsistencies that have hampered scientific progress in this important area and guide the rational design of unique, high–free-ion density ionic liquids and ionic liquid blends. PMID:23716690

  8. Effects of flotation-restricted environmental stimulation technique on stress-related muscle pain: what makes the difference in therapy--attention-placebo or the relaxation response?

    Science.gov (United States)

    Bood, Sven A; Sundequist, Ulf; Kjellgren, Anette; Nordstrom, Gun; Norlander, Torsten

    2005-01-01

    The purpose of the present study was to examine the potential effects of attention-placebo on flotation tank therapy. Flotation-restricted environmental stimulation technique is a method whereby an individual lies in a floating tank and all stimuli are reduced to a minimum. Thirty-two patients were diagnosed as having stress-related muscular pain. In addition, 16 of the participants had received the diagnosis of burnout depression. The patients were treated with flotation-restricted environmental stimulation technique for six weeks. One-half of the patients were also given special attention for 12 weeks (high attention), while the remainder received attention for only six weeks (normal attention). The participants exhibited lowered blood pressure, reduced pain, anxiety, depression, stress and negative affectivity, as well as increased optimism, energy and positive affectivity. The results were largely unaffected by the degree of attention-placebo or diagnosis. It was concluded that flotation therapy is an effective, noninvasive method for treating stress-related pain, and that the method is not more affected by placebo than by other methods currently used in pain treatment. The treatment of both burnout depression and pain related to muscle tension constitutes a major challenge for the patient as well as the care provider, an area in which great gains can be made if the treatment is effective. Flotation therapy may constitute an integral part of such treatment.

  9. A double-blind randomised, placebo-controlled trial evaluating the influence of oral long-acting muscle relaxant (Mebeverine MR), and insufflation with CO{sub 2} on pain associated with barium enema

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, A.S.; Chapman, A.H.; Wilson, D.; Culpan, A.G. [Department of Radiology, St. James' s University Hospital, Beckett Street, LS9 7TF, Leeds (United Kingdom)

    2003-07-01

    Previous investigators have shown significant benefit using CO{sub 2} for bowel insufflation. Others have suggested that the long-acting smooth muscle relaxant, Mebeverine, may be of benefit. We subjected this to a randomised double-blind trial. A total of 181 outpatients were randomised to receive either Mebeverine or placebo as pre-medication, and either air or CO{sub 2} for bowel insufflation, thus creating four treatment groups. Visual-analogue lines were used to record pain scores before, during, and up to 8 h following the enema. All groups showed increased pain scores during the enema, with peak pain scores at the end of the examination, falling to baseline scores by 8 h. Patients receiving the combination of C0{sub 2} and placebo had significantly lower pain scores at 1 and 4 h (P=0.00 and P=0.014, respectively; Kruskal-Wallis test) compared with all other groups. Having Mebeverine as a pre-medication did not significantly lower pain scores compared with placebo, and decreased the amount of benefit received from the CO{sub 2}. We confirm that CO{sub 2} is of benefit in decreasing pain during barium enema, and we recommend its routine use to improve the comfort of patients. Mebeverine is not of benefit, and its use as a pre-medication for enemas is not recommended. (orig.)

  10. Concurrent reflectance imaging and microdialysis in the freely behaving cat

    DEFF Research Database (Denmark)

    Poe, G R; Nitz, D A; Rector, D M

    1996-01-01

    We present a method to perform simultaneous microdialysis with light reflectance imaging of neural activity in a discrete brain region of the freely behaving animal. We applied this method to the dorsal hippocampus of freely behaving cats to (1) measure extracellular glutamate and reflectance...... imaged neural activity. Sequential images showed that cocaine perfusion elicited a propagating reflectance change as cocaine reached the tissue. Microperfusion of hypo-osmotic solution ( - 100 mOsm), which increases cell volume, decreased reflectance. Microperfusion of hyperosmotic sucrose solutions...

  11. A Novel Distributed Quantum-Behaved Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Yangyang Li

    2017-01-01

    Full Text Available Quantum-behaved particle swarm optimization (QPSO is an improved version of particle swarm optimization (PSO and has shown superior performance on many optimization problems. But for now, it may not always satisfy the situations. Nowadays, problems become larger and more complex, and most serial optimization algorithms cannot deal with the problem or need plenty of computing cost. Fortunately, as an effective model in dealing with problems with big data which need huge computation, MapReduce has been widely used in many areas. In this paper, we implement QPSO on MapReduce model and propose MapReduce quantum-behaved particle swarm optimization (MRQPSO which achieves parallel and distributed QPSO. Comparisons are made between MRQPSO and QPSO on some test problems and nonlinear equation systems. The results show that MRQPSO could complete computing task with less time. Meanwhile, from the view of optimization performance, MRQPSO outperforms QPSO in many cases.

  12. Two-Photon Functional Imaging of the Auditory Cortex in Behaving Mice: From Neural Networks to Single Spines

    Directory of Open Access Journals (Sweden)

    Ruijie Li

    2018-04-01

    Full Text Available In vivo two-photon Ca2+ imaging is a powerful tool for recording neuronal activities during perceptual tasks and has been increasingly applied to behaving animals for acute or chronic experiments. However, the auditory cortex is not easily accessible to imaging because of the abundant temporal muscles, arteries around the ears and their lateral locations. Here, we report a protocol for two-photon Ca2+ imaging in the auditory cortex of head-fixed behaving mice. By using a custom-made head fixation apparatus and a head-rotated fixation procedure, we achieved two-photon imaging and in combination with targeted cell-attached recordings of auditory cortical neurons in behaving mice. Using synthetic Ca2+ indicators, we recorded the Ca2+ transients at multiple scales, including neuronal populations, single neurons, dendrites and single spines, in auditory cortex during behavior. Furthermore, using genetically encoded Ca2+ indicators (GECIs, we monitored the neuronal dynamics over days throughout the process of associative learning. Therefore, we achieved two-photon functional imaging at multiple scales in auditory cortex of behaving mice, which extends the tool box for investigating the neural basis of audition-related behaviors.

  13. Botulinum Neurotoxin A Injections Influence Stretching of the Gastrocnemius Muscle-Tendon Unit in an Animal Model

    Directory of Open Access Journals (Sweden)

    Christopher J. Tuohy

    2012-08-01

    Full Text Available Botulinum Neurotoxin A (BoNT-A injections have been used for the treatment of muscle contractures and spasticity. This study assessed the influence of (BoNT-A injections on passive biomechanical properties of the muscle-tendon unit. Mouse gastrocnemius muscle (GC was injected with BoNT-A (n = 18 or normal saline (n = 18 and passive, non-destructive, in vivo load relaxation experimentation was performed to examine how the muscle-tendon unit behaves after chemical denervation with BoNT-A. Injection of BoNT-A impaired passive muscle recovery (15% vs. 35% recovery to pre-stretching baseline, p < 0.05 and decreased GC stiffness (0.531 ± 0.061 N/mm vs. 0.780 ± 0.037 N/mm, p < 0.05 compared to saline controls. The successful use of BoNT-A injections as an adjunct to physical therapy may be in part attributed to the disruption of the stretch reflex; thereby modulating in vivo passive muscle properties. However, it is also possible that BoNT-A injection may alter the structure of skeletal muscle; thus modulating the in vivo passive biomechanical properties of the muscle-tendon unit.

  14. Mechanical relaxation in glasses

    International Nuclear Information System (INIS)

    Hiki, Y.

    2004-01-01

    The basic properties of glasses and the characteristics of mechanical relaxation in glasses were briefly reviewed, and then our studies concerned were presented. Experimental methods adopted were viscosity, internal friction, ultrasonic attenuation, and Brillouin scattering measurements. The specimens used were several kinds of inorganic, organic, and metallic glasses. The measurements were mainly carried out from the room temperature up to the glass transition temperature, and the relaxation time was determined as a function of temperature. The 'double relaxation' composed of two Arrhenius-type relaxations was observed in many materials. In both relaxations, the 'compensation effect' showing a correlation of the pre-exponential factor and the activation energy was observed. These results were explained by considering the 'complex relaxation' due to cooperative motions of atoms or group of atoms. Values of activation energy near the glass transition determined by the various experimental methods were compared with each other

  15. [A study on Korean concepts of relaxation].

    Science.gov (United States)

    Park, J S

    1992-01-01

    Relaxation technique is an independent nursing intervention used in various stressful situations. The concept of relaxation must be explored for the meaning given by the people in their traditional thought and philosophy. Korean relaxation technique, wanting to become culturally acceptable and effective, is learning to recognize and develop Korean concepts, experiences, and musics of relaxation. This study was aimed at discovering Korean concepts, experiences and musics of relaxation and contributing the development of the relaxation technique for Korean people. The subjects were 59 nursing students, 39 hospitalized patients, 61 housewives, 21 rural residents and 16 researchers. Data were collected from September 4th to October 24th, 1991 by interviews or questionnaires. The data analysis was done by qualitative research method, and validity assured by conformation of the concept and category by 2 nursing scientists who had written a Master's thesis on the relaxation technique. The results of the study were summarized as follows; 1. The meaning of the relaxation concept; From 298 statements, 107 concepts were extracted and then 5 categories "Physical domain", "Psychological domain", "Complex domain", "Situation", and "environment" were organized. 'Don't have discomforts, 'don't have muscle tension', 'don't have energy (him in Korean)', 'don't have activities' subcategories were included in "Physical domain". 'Don't have anxiety', 'feel good', 'emotional stability', 'don't have wordly thoughts', 'feel one's brain muddled', 'loss of desire' subcategories were included in "physical domain" 'Comfort body and mind', 'don't have tension of body and mind', 'be sagged' 'liveliness of thoughts' subcategories were included in "Complex domain". 'Rest', 'sleep', 'others' subcategories were included in "Situation domain". And 'quite environment' & 'comfortable environment' subcategories were included in "Environmental domain". 2. The experiences of the relaxation; From 151

  16. Relaxation characteristics of hastelloy X

    International Nuclear Information System (INIS)

    Suzuki, Kazuhiko

    1980-02-01

    Relaxation diagrams of Hastelloy X (relaxation curves, relaxation design diagrams, etc.) were generated from the creep constitutive equation of Hastelloy X, using inelastic stress analysis code TEPICC-J. These data are in good agreement with experimental relaxation data of ORNL-5479. Three typical inelastic stress analyses were performed for various relaxation behaviors of the high-temperature structures. An attempt was also made to predict these relaxation behaviors by the relaxation curves. (author)

  17. Changes in emotional distress, short term memory, and sustained attention following 6 and 12 sessions of progressive muscle relaxation training in 10-11 years old primary school children.

    Science.gov (United States)

    Hashim, Hairul Anuar; Zainol, Nurul Ain

    2015-01-01

    This study compared the effects of 6 and 12 sessions of relaxation training on emotional distress, short-term memory, and sustained attention in primary school children. Participants (N = 132) aged 10 and 11 years old participated in this study. All participants and their parents provided written informed consent. Participants completed the measurement instruments before and after the completion of relaxation training. Nearly half (49%) of all respondents reported moderate to extremely severe stress, and 80 and 61% reported moderate to extremely severe anxiety and depression, respectively. The results of a one-way analysis of variance revealed a significant difference among the groups in mean changes in short-term memory. A greater memory increase was observed in the 12-session than in the six-session and no-training group. It can be conceived that 12-session of training should be considered when prescribing relaxation regimens as a nonspecific clinical treatment (i.e. for healthy students).

  18. TEACHING NEUROMUSCULAR RELAXATION.

    Science.gov (United States)

    NORRIS, JEANNE E.; STEINHAUS, ARTHUR H.

    THIS STUDY ATTEMPTED TO FIND OUT WHETHER (1) THE METHODS FOR ATTAINING NEUROMUSCULAR RELAXATION THAT HAVE PROVED FRUITFUL IN THE ONE-TO-ONE RELATIONSHIP OF THE CLINIC CAN BE SUCCESSFULLY ADAPTED TO THE TEACHER-CLASS RELATIONSHIP OF THE CLASSROOM AND GYMNASIUM, AND (2) NEUROMUSCULAR RELAXATION CAN BE TAUGHT SUCCESSFULLY BY AN APPROPRIATELY TRAINED…

  19. Relaxation of Anisotropic Glasses

    DEFF Research Database (Denmark)

    Deubener, Joachim; Martin, Birgit; Wondraczek, Lothar

    2004-01-01

    . When the load was removed at room temperature a permanent optical anisotropy (birefringence) was observed only perpendicular to cylinder axis and the pressure direction indicating complete elimination of thermal stresses. Relaxation of structural anisotropy was studied from reheating experiments using...... the energy release, thermo-mechanical and optical relaxation behaviour are drawn....

  20. Relaxation techniques for stress

    Science.gov (United States)

    ... raise your heart rate. This is called the stress response. Relaxation techniques can help your body relax and lower your blood pressure ... also many other types of breathing techniques you can learn. In many cases, you do not need much ... including those that cause stress. Meditation has been practiced for thousands of years, ...

  1. Calcium regulation and muscle disease.

    NARCIS (Netherlands)

    Gommans, I.M.P.; Vlak, M.; Haan, A. de; Engelen, B.G.M. van

    2002-01-01

    Changes in intracellular Ca2+-concentration play an important role in the excitation-contraction-relaxation cycle of skeletal muscle. In this review we describe various inheritable muscle diseases to highlight the role of Ca2+-regulatory mechanisms. Upon excitation the ryanodine receptor releases

  2. Anticipating and Resisting the Temptation to Behave Unethically.

    Science.gov (United States)

    Sheldon, Oliver J; Fishbach, Ayelet

    2015-07-01

    Ethical dilemmas pose a self-control conflict between pursuing immediate benefits through behaving dishonestly and pursuing long-term benefits through acts of honesty. Therefore, factors that facilitate self-control for other types of goals (e.g., health and financial) should also promote ethical behavior. Across four studies, we find support for this possibility. Specifically, we find that only under conditions that facilitate conflict identification--including the consideration of several decisions simultaneously (i.e., a broad decision frame) and perceived high connectedness to the future self--does anticipating a temptation to behave dishonestly in advance promote honesty. We demonstrate these interaction patterns between conflict identification and temptation anticipation in negotiation situations (Study 1), lab tasks (Study 2), and ethical dilemmas in the workplace (Studies 3-4). We conclude that identifying a self-control conflict and anticipating a temptation are two necessary preconditions for ethical decision making. © 2015 by the Society for Personality and Social Psychology, Inc.

  3. The relaxation time approximation

    International Nuclear Information System (INIS)

    Gairola, R.P.; Indu, B.D.

    1991-01-01

    A plausible approximation has been made to estimate the relaxation time from a knowledge of the transition probability of phonons from one state (r vector, q vector) to other state (r' vector, q' vector), as a result of collision. The relaxation time, thus obtained, shows a strong dependence on temperature and weak dependence on the wave vector. In view of this dependence, relaxation time has been expressed in terms of a temperature Taylor's series in the first Brillouin zone. Consequently, a simple model for estimating the thermal conductivity is suggested. the calculations become much easier than the Callaway model. (author). 14 refs

  4. The olfactory tubercle encodes odor valence in behaving mice.

    Science.gov (United States)

    Gadziola, Marie A; Tylicki, Kate A; Christian, Diana L; Wesson, Daniel W

    2015-03-18

    Sensory information acquires meaning to adaptively guide behaviors. Despite odors mediating a number of vital behaviors, the components of the olfactory system responsible for assigning meaning to odors remain unclear. The olfactory tubercle (OT), a ventral striatum structure that receives monosynaptic input from the olfactory bulb, is uniquely positioned to transform odor information into behaviorally relevant neural codes. No information is available, however, on the coding of odors among OT neurons in behaving animals. In recordings from mice engaged in an odor discrimination task, we report that the firing rate of OT neurons robustly and flexibly encodes the valence of conditioned odors over identity, with rewarded odors evoking greater firing rates. This coding of rewarded odors occurs before behavioral decisions and represents subsequent behavioral responses. We predict that the OT is an essential region whereby odor valence is encoded in the mammalian brain to guide goal-directed behaviors. Copyright © 2015 the authors 0270-6474/15/354515-13$15.00/0.

  5. BehavePlus fire modeling system, version 5.0: Variables

    Science.gov (United States)

    Patricia L. Andrews

    2009-01-01

    This publication has been revised to reflect updates to version 4.0 of the BehavePlus software. It was originally published as the BehavePlus fire modeling system, version 4.0: Variables in July, 2008.The BehavePlus fire modeling system is a computer program based on mathematical models that describe wildland fire behavior and effects and the...

  6. Modeling the dynamic characteristics of pneumatic muscle.

    Science.gov (United States)

    Reynolds, D B; Repperger, D W; Phillips, C A; Bandry, G

    2003-03-01

    A pneumatic muscle (PM) system was studied to determine whether a three-element model could describe its dynamics. As far as the authors are aware, this model has not been used to describe the dynamics of PM. A new phenomenological model consists of a contractile (force-generating) element, spring element, and damping element in parallel. The PM system was investigated using an apparatus that allowed precise and accurate actuation pressure (P) control by a linear servo-valve. Length change of the PM was measured by a linear potentiometer. Spring and damping element functions of P were determined by a static perturbation method at several constant P values. These results indicate that at constant P, PM behaves as a spring and damper in parallel. The contractile element function of P was determined by the response to a step input in P, using values of spring and damping elements from the perturbation study. The study showed that the resulting coefficient functions of the three-element model describe the dynamic response to the step input of P accurately, indicating that the static perturbation results can be applied to the dynamic case. This model is further validated by accurately predicting the contraction response to a triangular P waveform. All three elements have pressure-dependent coefficients for pressure P in the range 207 < or = P < or = 621 kPa (30 < or = P < or = 90 psi). Studies with a step decrease in P (relaxation of the PM) indicate that the damping element coefficient is smaller during relaxation than contraction.

  7. Sawtooth oscillations as MHD relaxation process in a plasma

    International Nuclear Information System (INIS)

    Yoshida, Zensho; Inoue, Nobuyuki; Ogawa, Yuichi

    1992-01-01

    The sawtooth oscillation in a tokamak plasma is a spontaneous relaxation process accompanying global instabilities which behave to reduce the internal magnetic energy. This phenomenon has a similarity to the MHD relaxation processes in Reversed Field Pinch (RFP) and Ultra Low Q (ULQ) plasmas. The self-stabilizing effect of instabilities with m (poloidal mode number) = 1 results in an increase in the central safety factor q(0). Nonlinear dynamics of m = 1 instabilities has been discussed both for global and local modes. The latter appears when a pitch minimum exists in the plasma, and is relevant to the compound sawtooth oscillation. The MHD relaxation is a restructuring process of the plasma current profile that is competitive with the resistive diffusion. (author)

  8. Pupils' reasons for learning and behaving and for not learning and behaving in English and maths lessons in a secondary school.

    Science.gov (United States)

    Norwich, B

    1999-12-01

    There is renewed interest in motivation and school learning, though there has been relatively little theory-linked research in English schools. In the first stage, to explore pupils' reasons for learning and behaving and for not learning and behaving in English, maths and other subjects. In the second stage, to examine differences in reasons across subjects, for learning and behaving and for not learning and behaving for boys and girls in two year groups in one secondary school. Stage 1, 16 pupils in years 7, 8 and 9 in two London secondary schools; Stage 2, 267 pupils in years 7 and 9 in one of these schools. Stage 1--semi-structured interviews were conducted to elicit different kinds of reasons conceptualised in terms of the Deci & Ryan's (1985) framework of self-determination. From these elicited reasons, an inventory 'Why I Learn' was designed. Stage 2--the inventory was administered to identify reasons for learning and behaving and for not learning and behaving in English and maths. Parent introjected reasons were the highest for learning and behaving while teacher introjected and intrinsic reasons were the lowest. Intrinsic reasons were highest for not learning and behaving. Year group differences in reason levels were more significant than gender or subject differences. Reasons for learning and behaving were more differentiated from each other than reasons for not learning and behaving. The results are discussed in terms of their significance for self-determination theory, research into the conditions promoting greater self-determination in school learning and further development of the inventory for programme evaluation.

  9. Appropriateness of Taped versus Live Relaxation in the Systematic Desensitization of Anticipatory Nausea and Vomiting in Cancer Patients.

    Science.gov (United States)

    Morrow, Gary R.

    1984-01-01

    Investigated whether the relaxation part of systematic desensitization could be learned by cancer patients from a prerecorded audiotape. Results showed four of five patients assigned to a taped-relaxation group experienced nausea while listening to the audiotape, whereas none of five patients taught muscle relaxation in person reported nausea. (BH)

  10. Voluntary running enhances glymphatic influx in awake behaving, young mice.

    Science.gov (United States)

    von Holstein-Rathlou, Stephanie; Petersen, Nicolas Caesar; Nedergaard, Maiken

    2018-01-01

    Vascular pathology and protein accumulation contribute to cognitive decline, whereas exercise can slow vascular degeneration and improve cognitive function. Recent investigations suggest that glymphatic clearance measured in aged mice while anesthetized is enhanced following exercise. We predicted that exercise would also stimulate glymphatic activity in awake, young mice with higher baseline glymphatic function. Therefore, we assessed glymphatic function in young female C57BL/6J mice following five weeks voluntary wheel running and in sedentary mice. The active mice ran a mean distance of 6km daily. We injected fluorescent tracers in cisterna magna of awake behaving mice and in ketamine/xylazine anesthetized mice, and later assessed tracer distribution in coronal brain sections. Voluntary exercise consistently increased CSF influx during wakefulness, primarily in the hypothalamus and ventral parts of the cortex, but also in the middle cerebral artery territory. While glymphatic activity was higher under ketamine/xylazine anesthesia, we saw a decrease in glymphatic function during running in awake mice after five weeks of wheel running. In summary, daily running increases CSF flux in widespread areas of the mouse brain, which may contribute to the pro-cognitive effects of exercise. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Hypothesis: solid tumours behave as systemic metabolic dictators.

    Science.gov (United States)

    Lee, Yang-Ming; Chang, Wei-Chun; Ma, Wen-Lung

    2016-06-01

    Current knowledge regarding mechanisms of carcinogenesis in human beings centres around the accumulation of genetic instability, amplified cellular signalling, disturbed cellular energy metabolism and microenvironmental regulation governed by complicated cell-cell interactions. In this article, we provide an alternative view of cancer biology. We propose that cancer behaves as a systemic dictator that interacts with tissues throughout the body to control their metabolism and eventually homeostasis. The mechanism of development of this endocrine organ-like tumour (EOLT) tissue might be the driving force for cancer progression. Here, we review the literature that led to the development of this hypothesis. The EOLT phenotype can be defined as a tumour that alters systemic homeostasis. The literature indicates that the EOLT phenotype is present throughout cancer progression. The feedback mechanism that governs the interaction between tumours and various organs is unknown. We believe that investigating the mechanism of EOLT development may advance the current knowledge of regulation within the tumour macroenvironment and consequently lead to new diagnostic methods and therapy. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  12. Fast optical signal not detected in awake behaving monkeys.

    Science.gov (United States)

    Radhakrishnan, Harsha; Vanduffel, Wim; Deng, Hong Ping; Ekstrom, Leeland; Boas, David A; Franceschini, Maria Angela

    2009-04-01

    While the ability of near-infrared spectroscopy (NIRS) to measure cerebral hemodynamic evoked responses (slow optical signal) is well established, its ability to measure non-invasively the 'fast optical signal' is still controversial. Here, we aim to determine the feasibility of performing NIRS measurements of the 'fast optical signal' or Event-Related Optical Signals (EROS) under optimal experimental conditions in awake behaving macaque monkeys. These monkeys were implanted with a 'recording well' to expose the dura above the primary visual cortex (V1). A custom-made optical probe was inserted and fixed into the well. The close proximity of the probe to the brain maximized the sensitivity to changes in optical properties in the cortex. Motion artifacts were minimized by physical restraint of the head. Full-field contrast-reversing checkerboard stimuli were presented to monkeys trained to perform a visual fixation task. In separate sessions, two NIRS systems (CW4 and ISS FD oximeter), which previously showed the ability to measure the fast signal in human, were used. In some sessions EEG was acquired simultaneously with the optical signal. The increased sensitivity to cortical optical changes with our experimental setup was quantified with 3D Monte Carlo simulations on a segmented MRI monkey head. Averages of thousands of stimuli in the same animal, or grand averages across the two animals and across repeated sessions, did not lead to detection of the fast optical signal using either amplitude or phase of the optical signal. Hemodynamic responses and visual evoked potentials were instead always detected with single trials or averages of a few stimuli. Based on these negative results, despite the optimal experimental conditions, we doubt the usefulness of non-invasive fast optical signal measurements with NIRS.

  13. Relaxed Binaural LCMV Beamforming

    NARCIS (Netherlands)

    Koutrouvelis, A.; Hendriks, R.C.; Heusdens, R.; Jensen, Jesper Rindom

    2017-01-01

    In this paper, we propose a new binaural beamforming technique, which can be seen as a relaxation of the linearly constrained minimum variance (LCMV) framework. The proposed method can achieve simultaneous noise reduction and exact binaural cue preservation of the target source, similar to the

  14. Force encoding in muscle spindles during stretch of passive muscle.

    Directory of Open Access Journals (Sweden)

    Kyle P Blum

    2017-09-01

    Full Text Available Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle

  15. Force encoding in muscle spindles during stretch of passive muscle.

    Science.gov (United States)

    Blum, Kyle P; Lamotte D'Incamps, Boris; Zytnicki, Daniel; Ting, Lena H

    2017-09-01

    Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs) of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt) predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening) of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle lengthening conditions

  16. A Comparison of Meditation with Other Relaxation Techniques.

    Science.gov (United States)

    Fling, Sheila

    This paper critiques a negative 1984 review, "Meditation and Somatic Arousal Reduction" (Holmes), on the absolute effectiveness of meditation in reducing somatic arousal and reviews research on the relative effectiveness of meditation compared to techniques such as biofeedback, hypnosis, progressive muscle relaxation, and autogenics in…

  17. Quantum Behaved Particle Swarm Optimization Algorithm Based on Artificial Fish Swarm

    OpenAIRE

    Yumin, Dong; Li, Zhao

    2014-01-01

    Quantum behaved particle swarm algorithm is a new intelligent optimization algorithm; the algorithm has less parameters and is easily implemented. In view of the existing quantum behaved particle swarm optimization algorithm for the premature convergence problem, put forward a quantum particle swarm optimization algorithm based on artificial fish swarm. The new algorithm based on quantum behaved particle swarm algorithm, introducing the swarm and following activities, meanwhile using the a...

  18. Hair Dye and Hair Relaxers

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women Hair Dye and Hair Relaxers Share Tweet Linkedin Pin it More sharing ... products. If you have a bad reaction to hair dyes and relaxers, you should: Stop using the ...

  19. Experiments in paramagnetic relaxation

    International Nuclear Information System (INIS)

    Lijphart, E.E.

    1976-01-01

    This thesis presents two attempts to improve the resolving power of the relaxation measurement technique. The first attempt reconsiders the old technique of steady state saturation. When used in conjunction with the pulse technique, it offers the possibility of obtaining additional information about the system in which all-time derivatives are zero; in addition, non-linear effects may be distinguished from each other. The second attempt involved a systematic study of only one system: Cu in the Tutton salts (K and Rb). The systematic approach, the high accuracy of the measurement and the sheer amount of experimental data for varying temperature, magnetic field and concentration made it possible in this case to separate the prevailing relaxation mechanisms reliably

  20. Artificial Muscle Kits for the Classroom

    Science.gov (United States)

    2004-01-01

    Commonly referred to as "artificial muscles," electroactive polymer (EAP) materials are lightweight strips of highly flexible plastic that bend or stretch when subjected to electric voltage. EAP materials may prove to be a substitution for conventional actuation components such as motors and gears. Since the materials behave similarly to biological muscles, this emerging technology has the potential to develop improved prosthetics and biologically-inspired robots, and may even one day replace damaged human muscles. The practical application of artificial muscles provides a challenge, however, since the material requires improved effectiveness and durability before it can fulfill its potential.

  1. Relaxation from particle production

    Energy Technology Data Exchange (ETDEWEB)

    Hook, Anson; Marques-Tavares, Gustavo [Stanford Institute for Theoretical Physics, Stanford University, Stanford, CA 94305 (United States)

    2016-12-20

    We consider using particle production as a friction force by which to implement a “Relaxion” solution to the electroweak hierarchy problem. Using this approach, we are able to avoid superplanckian field excursions and avoid any conflict with the strong CP problem. The relaxation mechanism can work before, during or after inflation allowing for inflationary dynamics to play an important role or to be completely decoupled.

  2. Magnetic relaxation in anisotropic magnets

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1971-01-01

    The line shape and the kinematic and thermodynamic slowing down of the critical and paramagnetic relaxation in axially anisotropic materials are discussed. Kinematic slowing down occurs only in the longitudinal relaxation function. The thermodynamic slowing down occurs in either the transverse...... or longitudinal relaxation function depending on the sign of the axial anisotropy....

  3. Momentum constraint relaxation

    International Nuclear Information System (INIS)

    Marronetti, Pedro

    2006-01-01

    Full relativistic simulations in three dimensions invariably develop runaway modes that grow exponentially and are accompanied by violations of the Hamiltonian and momentum constraints. Recently, we introduced a numerical method (Hamiltonian relaxation) that greatly reduces the Hamiltonian constraint violation and helps improve the quality of the numerical model. We present here a method that controls the violation of the momentum constraint. The method is based on the addition of a longitudinal component to the traceless extrinsic curvature A ij -tilde, generated by a vector potential w i , as outlined by York. The components of w i are relaxed to solve approximately the momentum constraint equations, slowly pushing the evolution towards the space of solutions of the constraint equations. We test this method with simulations of binary neutron stars in circular orbits and show that it effectively controls the growth of the aforementioned violations. We also show that a full numerical enforcement of the constraints, as opposed to the gentle correction of the momentum relaxation scheme, results in the development of instabilities that stop the runs shortly

  4. Magnetization relaxation of single molecule magnets after field cooling

    Science.gov (United States)

    Fernandez, Julio F.; Alonso, Juan J.

    2004-03-01

    Magnetic clusters, such as Fe8 and Mn_12, behave at low temperatures as large single spins S. In crystals, anisotropy energies U allow magnetic relaxation only through tunneling at k_BTstackrelspins with dipolar interactions. To mimic tunneling effects, a spin on a lattice site where h is within some tunnel window -h_w

  5. Numerical investigation for one bad-behaved flow in a Pelton turbine

    International Nuclear Information System (INIS)

    Wei, X Z; Yang, K; Wang, H J; Gong, R Z; Li, D Y

    2015-01-01

    The gas-liquid two-phase flow in pelton turbines is very complicated, there are many kinds of bad-behaved flow in pelton turbines. In this paper, CFD numerical simulation for the pelton turbine was conducted using VOF two-phase model. One kind of bad-behaved flow caused by the two jets was captured, and the bad-behaved flow was analysed by torque on buckets. It can be concluded that the angle between the two jets and the value of ratio of runner diameter and jet diameter are important parameters for the bad-behaved flow. Furthermore, the reason why the efficiency of some multi-jet type turbines is very low can be well explained by the analysis of bad-behaved flow. Finally, some suggestions for improvement were also provided in present paper

  6. Numerical investigation for one bad-behaved flow in a Pelton turbine

    Science.gov (United States)

    Wei, X. Z.; Yang, K.; Wang, H. J.; Gong, R. Z.; Li, D. Y.

    2015-01-01

    The gas-liquid two-phase flow in pelton turbines is very complicated, there are many kinds of bad-behaved flow in pelton turbines. In this paper, CFD numerical simulation for the pelton turbine was conducted using VOF two-phase model. One kind of bad-behaved flow caused by the two jets was captured, and the bad-behaved flow was analysed by torque on buckets. It can be concluded that the angle between the two jets and the value of ratio of runner diameter and jet diameter are important parameters for the bad-behaved flow. Furthermore, the reason why the efficiency of some multi-jet type turbines is very low can be well explained by the analysis of bad-behaved flow. Finally, some suggestions for improvement were also provided in present paper.

  7. Variational formulation of relaxed and multi-region relaxed magnetohydrodynamics

    Science.gov (United States)

    Dewar, R. L.; Yoshida, Z.; Bhattacharjee, A.; Hudson, S. R.

    2015-12-01

    > Ideal magnetohydrodynamics (IMHD) is strongly constrained by an infinite number of microscopic constraints expressing mass, entropy and magnetic flux conservation in each infinitesimal fluid element, the latter preventing magnetic reconnection. By contrast, in the Taylor relaxation model for formation of macroscopically self-organized plasma equilibrium states, all these constraints are relaxed save for the global magnetic fluxes and helicity. A Lagrangian variational principle is presented that leads to a new, fully dynamical, relaxed magnetohydrodynamics (RxMHD), such that all static solutions are Taylor states but also allows state with flow. By postulating that some long-lived macroscopic current sheets can act as barriers to relaxation, separating the plasma into multiple relaxation regions, a further generalization, multi-region relaxed magnetohydrodynamics (MRxMHD) is developed.

  8. Dynamics of relaxed inflation

    Science.gov (United States)

    Tangarife, Walter; Tobioka, Kohsaku; Ubaldi, Lorenzo; Volansky, Tomer

    2018-02-01

    The cosmological relaxation of the electroweak scale has been proposed as a mechanism to address the hierarchy problem of the Standard Model. A field, the relaxion, rolls down its potential and, in doing so, scans the squared mass parameter of the Higgs, relaxing it to a parametrically small value. In this work, we promote the relaxion to an inflaton. We couple it to Abelian gauge bosons, thereby introducing the necessary dissipation mechanism which slows down the field in the last stages. We describe a novel reheating mechanism, which relies on the gauge-boson production leading to strong electro-magnetic fields, and proceeds via the vacuum production of electron-positron pairs through the Schwinger effect. We refer to this mechanism as Schwinger reheating. We discuss the cosmological dynamics of the model and the phenomenological constraints from CMB and other experiments. We find that a cutoff close to the Planck scale may be achieved. In its minimal form, the model does not generate sufficient curvature perturbations and additional ingredients, such as a curvaton field, are needed.

  9. Role of ERK signaling pathway in up-regulation of γ-AChR during development of resistance to non-depolarizing muscular relaxants in skeletal muscles of burned rats%ERK信号通路在烧伤大鼠骨骼肌对非去极化肌松药抵抗形成时γ-AChR上调中的作用

    Institute of Scientific and Technical Information of China (English)

    靳天; 王宏; 吴进; 李士通

    2016-01-01

    Objective To evaluate the role of ERK signaling pathway in up-regulation of fetal gamma-acetylcholine receptor (μ-AChR) during the development of resistance to non-depolarizing muscular relaxants in skeletal muscles of burned rats.Methods Thirty adult male SPF Sprague-Dawley rats,weighing 230-250 g,aged 9-10 weeks,were randomly divided into 3 groups (n=10 each) using a random number table:control group (C group),burn group (B group) and ERK1/2 inhibitor U0126 group (U group).The surface area of bilateral hindlimbs was shaved,and the tibialis anterior muscle of the right hiudlimb was exposed to 95 ℃ copper for 12 s in anesthetized rats.At 1.5 h after burn,15 mg/kg U0126 was injected intraperitoneally in group U,and the equal volume of dimethyl sulfoxide was given in C and B groups.The tibialis anterior muscle was obtained on 7th day after establishment of the model for determination of the expression of μ-AChR and adult epsilon-AChR (ε-AChR) mRNA in skeletal muscle cells using real-time polymerase chain reaction.The concentration-effect curve of rocuronium was drawn using muscular tension experiment,and the half inhibitory concentration (IC50) and 95% confidence interval were calculated.Resuits Compared with group C,the expression of μ-AChR mRNA in skeletal muscle cells was significantly up-regulated,and the IC50 was significantly increased in group B (P<0.05).Compared with group B,the expression of γ-AChR mRNA in skeletal muscle cells was significantly down-regulated,and the IC50 was significantly decreased in group U (P<0.05).There was no significant difference in the expression of ε-AChR in skeletal muscle cells between the three groups (P>0.05).Conclusion Up-regulation of μ,-AChR is dependent on activation of ERK signaling pathway during the development of resistance to non-depolarizing muscular relaxants in skeletal muscles of burned rats.%目的 评价细胞外信号调节激酶(ERK)信号通路在烧伤大鼠骨骼肌对非去极化肌松药

  10. Muscle Deoxygenation Causes Muscle Fatigue

    Science.gov (United States)

    Murthy, G.; Hargens, A. R.; Lehman, S.; Rempel, D.

    1999-01-01

    Muscle fatigue is a common musculoskeletal disorder in the work place, and may be a harbinger for more disabling cumulative trauma disorders. Although the cause of fatigue is multifactorial, reduced blood flow and muscle oxygenation may be the primary factor in causing muscle fatigue during low intensity muscle exertion. Muscle fatigue is defined as a reduction in muscle force production, and also occurs among astronauts who are subjected to postural constraints while performing lengthy, repetitive tasks. The objectives of this research are to: 1) develop an objective tool to study the role of decreased muscle oxygenation on muscle force production, and 2) to evaluate muscle fatigue during prolonged glovebox work.

  11. Muscle Cramps

    Science.gov (United States)

    ... Talk to your provider about the risks and benefits of medicines. How can I prevent muscle cramps? To prevent muscle cramps, you can Stretch your muscles, especially before exercising. If you often get leg cramps at night, ...

  12. Vibrational energy transfer in selectively excited diatomic molecules. [Relaxation rates, self-relaxation, upper limits

    Energy Technology Data Exchange (ETDEWEB)

    Dasch, C.J.

    1978-09-01

    Single rovibrational states of HCl(v=2), HBr(v=2), DCl(v=2), and CO(v=2) were excited with a pulsed optical parametric oscillator (OPO). Total vibrational relaxation rates near - resonance quenchers were measured at 295/sup 0/K using time resolved infrared fluorescence. These rates are attributed primarily to V - V energy transfer, and they generally conform to a simple energy gap law. A small deviation was found for the CO(v) + DCl(v') relaxation rates. Upper limits for the self relaxation by V - R,T of HCl(v=2) and HBr(v=2) and for the two quantum exchange between HCl and HBr were determined. The HF dimer was detected at 295/sup 0/K and 30 torr HF pressure with an optoacoustic spectrometer using the OPO. Pulsed and chopped, resonant and non-resonant spectrophones are analyzed in detail. From experiments and first order perturbation theory, these V - V exchange rates appear to behave as a first order perturbation in the vibrational coordinates. The rotational dynamics are known to be complicated however, and the coupled rotational - vibrational dynamics were investigated theoreticaly in infinite order by the Dillon and Stephenson and the first Magnus approximations. Large ..delta..J transitions appear to be important, but these calculations differ by orders of magnitude on specific rovibrational transition rates. Integration of the time dependent semiclassical equations by a modified Gordon method and a rotationally distorted wave approximation are discussed as methods which would treat the rotational motion more accurately. 225 references.

  13. Comparing the effects of relaxation technique and inhalation aromatherapy on fatigue in patients undergoing hemodialysis.

    Science.gov (United States)

    Hassanzadeh, Mohammadali; Kiani, Fatemeh; Bouya, Salehoddin; Zarei, Mohammad

    2018-05-01

    This study aimed to compare the effects of relaxation techniques on fatigue in hemodialysis patients. This clinical trial study was conducted on 105 hemodialysis patients. The subjects were categorized into three groups as: relaxation, aromatherapy and control. In the relaxation group, Benson muscle relaxation techniques were employed; in the aromatherapy group, the inhalation of two drops of 5% lavender essential oil used and the control group only received regular healthcare actions. Data collected by using brief fatigue inventory, before and after the intervention. Results of the current study indicated significant differences in the mean of changes in fatigue scores before and after the intervention between the relaxation and aromatherapy groups, but the difference was insignificant in the control group. Aromatherapy with lavender essential oil can decrease the level of fatigue in the patients undergoing hemodialysis compared to Benson relaxation techniques. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Improved quantum-behaved particle swarm optimization with local search strategy

    Directory of Open Access Journals (Sweden)

    Maolong Xi

    2017-03-01

    Full Text Available Quantum-behaved particle swarm optimization, which was motivated by analysis of particle swarm optimization and quantum system, has shown compared performance in finding the optimal solutions for many optimization problems to other evolutionary algorithms. To address the problem of premature, a local search strategy is proposed to improve the performance of quantum-behaved particle swarm optimization. In proposed local search strategy, a super particle is presented which is a collection body of randomly selected particles’ dimension information in the swarm. The selected probability of particles in swarm is different and determined by their fitness values. To minimization problems, the fitness value of one particle is smaller; the selected probability is more and will contribute more information in constructing the super particle. In addition, in order to investigate the influence on algorithm performance with different local search space, four methods of computing the local search radius are applied in local search strategy and propose four variants of local search quantum-behaved particle swarm optimization. Empirical studies on a suite of well-known benchmark functions are undertaken in order to make an overall performance comparison among the proposed methods and other quantum-behaved particle swarm optimization. The simulation results show that the proposed quantum-behaved particle swarm optimization variants have better advantages over the original quantum-behaved particle swarm optimization.

  15. Relaxation effect of abacavir on rat basilar arteries.

    Directory of Open Access Journals (Sweden)

    Rachel Wai Sum Li

    Full Text Available The use of abacavir has been linked with increased cardiovascular risk in patients with human immunodeficiency virus infection; however, the mechanism involved remains unclear. We hypothesize that abacavir may impair endothelial function. In addition, based on the structural similarity between abacavir and adenosine, we propose that abacavir may affect vascular contractility through endogenous adenosine release or adenosine receptors in blood vessels.The relaxation effect of abacavir on rat basilar arteries was studied using the myograph technique. Cyclic GMP and AMP levels were measured by immunoassay. The effects of abacavir on nucleoside transporters were studied using radiolabeled nucleoside uptake experiments. Ecto-5' nucleotidase activity was determined by measuring the generation of inorganic phosphate using adenosine monophosphate as the substrate.Abacavir induced the relaxation of rat basilar arteries in a concentration-dependent manner. This relaxation was abolished when endothelium was removed. In addition, the relaxation was diminished by the nitric oxide synthase inhibitor, L-NAME, the guanylyl cyclase inhibitor, ODQ, and the protein kinase G inhibitor, KT5820. Abacavir also increased the cGMP level in rat basilar arteries. Abacavir-induced relaxation was also abolished by adenosine A2 receptor blockers. However, abacavir had no effect on ecto-5' nucleotidase and nucleoside transporters. Short-term and long-term treatment of abacavir did not affect acetylcholine-induced relaxation in rat basilar arteries.Abacavir induces acute endothelium-dependent relaxation of rat basilar arteries, probably through the activation of adenosine A2 receptors in endothelial cells, which subsequently leads to the release of nitric oxide, resulting in activation of the cyclic guanosine monophosphate/protein kinase G-dependent pathway in vascular smooth muscle cells. It is speculated that abacavir-induced cardiovascular risk may not be related to

  16. Temperature dependence of the kinetics of isometric myocardium relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Izakov, V.Ya.; Bykov, B.L.; Kimmelman, I.Ya.

    1981-11-01

    The dependence of the exponential decay constant expressing the isometric relaxation of the myocardium on temperature is investigated in animals with various specific contents of myocardial sarcoplasmic reticulum. Experiments were performed on cardiac ventricles and atria isolated from rabbits, frogs and turtles and electrically stimulated to produce maximal contraction at temperatures from 10 to 35 C. Arrhenius plots derived from the data are found to be linear in the myocardia of the rabbit and frog, with a greater activation energy for the relaxation found in the rabbit. The Arrhenius plot for the turtle, which has a sarcoplasmic reticulum content intermediate between those of the frog and rabbit, corresponds to two straight lines with different activation energies. Results thus support the hypothesis of two separate mechanisms of calcium removal, involving the sarcoplasmic reticulum and cellular membrane, in muscle relaxation.

  17. Contracture of Slow Striated Muscle during Calcium Deprivation

    Science.gov (United States)

    Irwin, Richard L.; Hein, Manfred M.

    1963-01-01

    When deprived of calcium the slow striated muscle fibers of the frog develop reversible contractures in either hypertonic or isotonic solutions. While calcium deprivation continues because of a flowing calcium-free solution the muscles relax slowly and completely. Restoration of calcium during contracture relaxes the muscle promptly to initial tension. When relaxed during calcium lack the return of calcium does not change tension and the muscle stays relaxed. When contractures are induced by solutions containing small amounts of calcium relaxation does not occur or requires several hours. The rate of tension development depends upon the rate at which calcium moves outward since the contractures develop slower in low concentrations of calcium and are absent or greatly slowed in a stagnant calcium-free solution. Withdrawal of calcium prevents the contractile responses to ACh, KCl, or electrical stimulation through the nerve. Muscles return to their original excitability after calcium is restored. Origin of the contractures is unrelated to nerve activity since they are maximal during transmission failure from calcium lack, occur in denervated muscles, and are not blocked by high concentrations of d-tubocurarine, procaine, or atropine. The experiments also indicate that the contractures do not originate from repetitive activity of muscle membranes. The findings are most simply explained by relating the outward movement of calcium as a link for initiating contraction in slow type striated muscle. PMID:14065284

  18. Relaxed states with plasma flow

    International Nuclear Information System (INIS)

    Avinash, K.; Taylor, J.B.

    1991-01-01

    In the theory of relaxation, a turbulent plasma reaches a state of minimum energy subject to constant magnetic helicity. In this state the plasma velocity is zero. Attempts have been made by introducing a number of different constraints, to obtain relaxed states with plasma flow. It is shown that these alternative constraints depend on two self-helicities, one for ions, and one for electrons. However, whereas there are strong arguments for the effective invariance of the original magnetic-helicity, these arguments do not apply to the self-helicities. Consequently the existence of relaxed states with flow remains in doubt. (author)

  19. Fetal response to abbreviated relaxation techniques. A randomized controlled study.

    Science.gov (United States)

    Fink, Nadine S; Urech, Corinne; Isabel, Fornaro; Meyer, Andrea; Hoesli, Irène; Bitzer, Johannes; Alder, Judith

    2011-02-01

    stress during pregnancy can have adverse effects on the course of pregnancy and on fetal development. There are few studies investigating the outcome of stress reduction interventions on maternal well-being and obstetric outcome. this study aims (1) to obtain fetal behavioral states (quiet/active sleep, quiet/active wakefulness), (2) to investigate the effects of maternal relaxation on fetal behavior as well as on uterine activity, and (3) to investigate maternal physiological and endocrine parameters as potential underlying mechanisms for maternal-fetal relaxation-transferral. the behavior of 33 fetuses was analyzed during laboratory relaxation/quiet rest (control group, CG) and controlled for baseline fetal behavior. Potential associations between relaxation/quiet rest and fetal behavior (fetal heart rate (FHR), FHR variation, FHR acceleration, and body movements) and uterine activity were studied, using a computerized cardiotocogram (CTG) system. Maternal heart rate, blood pressure, cortisol, and norepinephrine were measured. intervention (progressive muscle relaxation, PMR, and guided imagery, GI) showed changes in fetal behavior. The intervention groups had higher long-term variation during and after relaxation compared to the CG (p=.039). CG fetuses had more FHR acceleration, especially during and after quiet rest (p=.027). Women in the PMR group had significantly more uterine activity than women in the GI group (p=.011) and than CG women. Maternal heart rate, blood pressure, and stress hormones were not associated with fetal behavior. this study indicates that the fetus might participate in maternal relaxation and suggests that GI is superior to PMR. This could especially be true for women who tend to direct their attention to body sensations such as abdominal activity. 2010 Elsevier Ltd. All rights reserved.

  20. Wave fronts, pulses and wave trains in photoexcited superlattices behaving as excitable or oscillatory media

    International Nuclear Information System (INIS)

    Arana, J I; Bonilla, L L; Grahn, H T

    2011-01-01

    Undoped and strongly photoexcited semiconductor superlattices with field-dependent recombination behave as excitable or oscillatory media with spatially discrete nonlinear convection and diffusion. Infinitely long, dc-current-biased superlattices behaving as excitable media exhibit wave fronts with increasing or decreasing profiles, whose velocities can be calculated by means of asymptotic methods. These superlattices can also support pulses of the electric field. Pulses moving downstream with the flux of electrons can be constructed from their component wave fronts, whereas pulses advancing upstream do so slowly and experience saltatory motion: they change slowly in long intervals of time separated by fast transitions during which the pulses jump to the previous superlattice period. Photoexcited superlattices can also behave as oscillatory media and exhibit wave trains. (paper)

  1. Age differences in how consumers behave following exposure to DTC advertising.

    Science.gov (United States)

    DeLorme, Denise E; Huh, Jisu; Reid, Leonard N

    2006-01-01

    This study was conducted to provide additional evidence on how consumers behave following direct-to-consumer (DTC) advertising exposure and to determine if there are differences in ad-prompted acts (drug inquiry and drug requests) between different age groups (i.e., older, mature, and younger adults). The results suggest that younger, mature, and older consumers are all moved to act by DTC drug ads, but that each age group behaves in different ways. Somewhat surprisingly, age was not predictive of ad-prompted behavior. DTC advertising was no more effective at moving older consumers to behave than their younger counterparts. These results suggest that age does not matter that much when it comes to the "moving power" of prescription drug advertising, even though research indicates that older consumers are more vulnerable to the persuasive effects of communication.

  2. ASM-024, a piperazinium compound, promotes the in vitro relaxation of β2-adrenoreceptor desensitized tracheas.

    Science.gov (United States)

    Israël-Assayag, Evelyne; Beaulieu, Marie-Josée; Cormier, Yvon

    2015-01-01

    Inhaled β2-adrenoreceptor agonists are widely used in asthma and chronic obstructive pulmonary disease (COPD) for bronchoconstriction relief. β2-Adrenoreceptor agonists relax airway smooth muscle cells via cyclic adenosine monophosphate (cAMP) mediated pathways. However, prolonged stimulation induces functional desensitization of the β2-adrenoreceptors (β2-AR), potentially leading to reduced clinical efficacy with chronic or prolonged administration. ASM-024, a small synthetic molecule in clinical stage development, has shown activity at the level of nicotinic receptors and possibly at the muscarinic level and presents anti-inflammatory and bronchodilator properties. Aerosolized ASM-024 reduces airway resistance in mice and promotes in-vitro relaxation of tracheal and bronchial preparations from animal and human tissues. ASM-024 increased in vitro relaxation response to maximally effective concentration of short-acting beta-2 agonists in dog and human bronchi. Although the precise mechanisms by which ASM-024 promotes airway smooth muscle (ASM) relaxation remain unclear, we hypothesized that ASM-024 will attenuate and/or abrogate agonist-induced contraction and remain effective despite β2-AR tachyphylaxis. β2-AR tachyphylaxis was induced with salbutamol, salmeterol and formoterol on guinea pig tracheas. The addition of ASM-024 relaxed concentration-dependently intact or β2-AR desensitized tracheal rings precontracted with methacholine. ASM-024 did not induce any elevation of intracellular cAMP in isolated smooth muscle cells; moreover, blockade of the cAMP pathway with an adenylate cyclase inhibitor had no significant effect on ASM-024-induced guinea pig trachea relaxation. Collectively, these findings show that ASM-024 elicits relaxation of β2-AR desensitized tracheal preparations and suggest that ASM-024 mediates smooth muscle relaxation through a different target and signaling pathway than β2-adrenergic receptor agonists. These findings suggest ASM-024

  3. Relaxed states of tokamak plasmas

    International Nuclear Information System (INIS)

    Kucinski, M.Y.; Okano, V.

    1993-01-01

    The relaxed states of tokamak plasmas are studied. It is assumed that the plasma relaxes to a quasi-steady state which is characterized by a minimum entropy production rate, compatible with a number of prescribed conditions and pressure balance. A poloidal current arises naturally due to the anisotropic resistivity. The minimum entropy production theory is applied, assuming the pressure equilibrium as fundamental constraint on the final state. (L.C.J.A.)

  4. Negative magnetic relaxation in superconductors

    Directory of Open Access Journals (Sweden)

    Krasnoperov E.P.

    2013-01-01

    Full Text Available It was observed that the trapped magnetic moment of HTS tablets or annuli increases in time (negative relaxation if they are not completely magnetized by a pulsed magnetic field. It is shown, in the framework of the Bean critical-state model, that the radial temperature gradient appearing in tablets or annuli during a pulsed field magnetization can explain the negative magnetic relaxation in the superconductor.

  5. Relaxation effects in ferrous complexes

    International Nuclear Information System (INIS)

    Nicolini, C.; Mathieu, J.P.; Chappert, J.

    1976-01-01

    The slow relaxation mechanism of the Fe 2+ ion in the tri-fluorinated TF(acac) and hexafluorinated HF(acac) complexes of Fe(II) acetylacetonate was investigated. The 300K and 77K Moessbauer spectra for TF(acac) consist in a slightly asymmetric quadrupole doublet. On the contrary, at 4.2K the higher energy line is strongly widened; that is typical of a slowing down in the electron relaxation frequency [fr

  6. [Asymmetric hypertrophy of the masticatory muscles].

    Science.gov (United States)

    Arzul, L; Corre, P; Khonsari, R H; Mercier, J-M; Piot, B

    2012-06-01

    Hypertrophy of the masticatory muscles most commonly affects the masseter. Less common cases of isolated or associated temporalis hypertrophy are also reported. Parafunctional habits, and more precisely bruxism, can favor the onset of the hypertrophy. This condition is generally idiopathic and can require both medical and/or surgical management. A 29-year-old patient was referred to our department for an asymmetric swelling of the masticatory muscles. Physical examination revealed a bilateral hypertrophy of the masticatory muscles, predominantly affecting the right temporalis and the left masseter. Major bruxism was assessed by premature dental wearing. The additional examinations confirmed the isolated muscle hypertrophy. Benign asymmetric hypertrophy of the masticatory muscles promoted by bruxism was diagnosed. Treatment with injections of type A botulinum toxin was conducted in association with a splint and relaxation. Its effectiveness has been observed at six months. Few cases of unilateral or bilateral temporalis hypertrophy have been reported, added to the more common isolated masseter muscles hypertrophy. The diagnosis requires to rule out secondary hypertrophies and tumors using Magnetic Resonance Imaging. The condition is thought to be favoured by parafunctional habits such as bruxism. The conservative treatment consists in reducing the volume of the masticatory muscles using intramuscular injections of type A botulinum toxin. Other potential conservative treatments are wearing splints and muscle relaxant drugs. Surgical procedures aiming to reduce the muscle volume and/or the bone volume (mandibular gonioplasty) can be proposed. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  7. The influence of external compression on muscle blood flow during exercise

    International Nuclear Information System (INIS)

    Styf, J.

    1990-01-01

    Intramuscular pressures and muscle blood flow were measured in the anterior tibial muscle during dynamic concentric exercise in 14 subjects. Pressures were recorded by the microcapillary infusion method and muscle blood flow by the 133-Xenon clearance technique. Muscle blood flow during constant exercise decreased from 34.5 (SD = 10.3) to 10.6 (SD = 4.9) ml/100 g/min (P less than 0.001) when muscle relaxation pressure was increased from 13.5 (SD = 2.7) to 39.9 (SD = 9.0) mm Hg by external compression. Muscle relaxation pressure during exercise is the intramuscular pressure between contractions. External compression of the lower limb during exercise impedes muscle blood flow by increasing muscle relaxation pressure. The experimental model seems suitable to study the influence of external compression by knee braces on intramuscular pressure during exercise

  8. Mechanism of resveratrol-induced relaxation of the guinea pig fundus.

    Science.gov (United States)

    Tsai, Ching-Chung; Tey, Shu-Leei; Lee, Ming-Che; Liu, Ching-Wen; Su, Yu-Tsun; Huang, Shih-Che

    2018-04-01

    Resveratrol is a polyphenolic compound that can be isolated from plants and also is a constituent of red wine. Resveratrol induces relaxation of vascular smooth muscle and may prevent cardiovascular diseases. Impaired gastric accommodation plays an important role in functional dyspepsia and fundic relaxation and is a therapeutic target of functional dyspepsia. Although drugs for fundic relaxation have been developed, these types of drugs are still rare. The purpose of this study was to investigate the relaxant effects of resveratrol in the guinea pig fundus. We studied the relaxant effects of resveratrol in the guinea pig fundus. In addition, we investigated the mechanism of resveratrol-induced relaxation on the guinea pig fundus by using tetraethylammonium (a non-selective potassium channel blocker), apamine (a selective inhibitor of the small conductance calcium-activated potassium channel), iberiotoxin (an inhibitor of large conductance calcium-activated potassium channels), glibenclamide (an ATP-sensitive potassium channel blocker), KT 5720 (a cAMP-dependent protein kinase A inhibitor), KT 5823 (a cGMP-dependent protein kinase G inhibitor), NG-nitro-L-arginine (a competitive inhibitor of nitric oxide synthase), tetrodotoxin (a selective neuronal Na + channel blocker), ω-conotoxin GVIA (a selective neuronal Ca 2+ channel blocker) and G-15 (a G-protein coupled estrogen receptor antagonist). The results of this study showed that resveratrol has potent and dose-dependent relaxant effects on the guinea pig fundic muscle. In addition, the results showed that resveratrol-induced relaxation of the guinea pig fundus occurs through nitric oxide and ATP-sensitive potassium channels. This study provides the first evidence concerning the relaxant effects of resveratrol in the guinea pig fundic muscle strips. Furthermore, resveratrol may be a potential drug to relieve gastrointestinal dyspepsia. Copyright © 2018 Elsevier GmbH. All rights reserved.

  9. Effect of Progressive Muscle Relaxation in Female Health Care ...

    African Journals Online (AJOL)

    levels among female health care professionals in the age group of 25‑35 years and its impact on health. Subjects ... For these, initial assessment of anthropometric measurement, electrocardiogram ... report of the American Foundation for Suicide Prevention, ... most widely used psychological instrument for measuring the.

  10. Gamma dosimetric parameters in some skeletal muscle relaxants

    Indian Academy of Sciences (India)

    H C MANJUNATHA

    2017-08-29

    Aug 29, 2017 ... The measured values agree with the theoretical values. The studied ... directly related to the quality of radiation and the dose- fractionation protocol. ..... the instrument is +5 V for digital circuits and +9 and. −9 V for analog ...

  11. Intubation without muscle relaxation for suspension laryngoscopy: A ...

    African Journals Online (AJOL)

    2013-11-12

    Nov 12, 2013 ... laryngoscopy under intubation with propofol and remifentanil alone for vocal fold nodule (VFN) excision. ... laryngological procedure, achieves a definitive treatment ... Hospital, Dongying, 4Department of Gastroenterology, The Second Hospital ..... on the dose and infusion rate of propofol and remifentanil.

  12. Effect of Progressive Muscle Relaxation in Female Health Care ...

    African Journals Online (AJOL)

    After 3 months, the lipid profile and vital parameters, Perceived Stress Scale values were re-evaluated and subjects were asked to repeat the same exercises and data thus recorded were analyzed using Statistical Package for the Social Sciences (SPSS) version 16 (SPSS Inc. Released 2007. SPSS for Windows, Version ...

  13. Intubation without muscle relaxation for suspension laryngoscopy: A ...

    African Journals Online (AJOL)

    Objective and Aim: The objective of the following study is to examine the effectiveness and safety of suspension laryngoscopy under intubation with propofol and remifentanil alone for vocal fold nodule (VFN) excision. Materials and Methods: A total of 40 patients were equally and randomly assigned to elective VFN excision ...

  14. Role of Botox in Efficient Muscle Relaxation and Treatment Outcome ...

    African Journals Online (AJOL)

    sterilized and vacuum‑dried powder diluted with saline solution. In implant therapy ... maxillofacial fractures associated with road traffic accident. Inappropriately ... previous levels once the effect of the drug has subsided. In spite of several ...

  15. Relaxation of Isolated Ventricular Cardiomyocytes by a Voltage-Dependent Process

    Science.gov (United States)

    Bridge, John H. B.; Spitzer, Kenneth W.; Ershler, Philip R.

    1988-08-01

    Cell contraction and relaxation were measured in single voltage-clamped guinea pig cardiomyocytes to investigate the contribution of sarcolemmal Na+-Ca2+ exchange to mechanical relaxation. Cells clamped from -80 to 0 millivolts displayed initial phasic and subsequent tonic contractions; caffeine reduced or abolished the phasic and enlarged the tonic contraction. The rate of relaxation from tonic contractions was steeply voltage-dependent and was significantly slowed in the absence of a sarcolemmal Na+ gradient. Tonic contractions elicited in the absence of a Na+ gradient promptly relaxed when external Na+ was applied, reflecting activation of Na+-Ca2+ exchange. It appears that a voltage-dependent Na+-Ca2+ exchange can rapidly mechanically relax mammalian heart muscle.

  16. Hippocampal activity during transient respiratory events in the freely behaving cat

    DEFF Research Database (Denmark)

    Poe, G R; Kristensen, Morten Pilgaard; Rector, D M

    1996-01-01

    We measured dorsal hippocampal activity accompanying sighs and apnea using reflectance imaging and electrophysiologic measures in freely behaving cats. Reflected 660-nm light from a 1-mm2 area of CA1 was captured during sighs and apnea at 25 Hz through a coherent image conduit coupled to a charge...

  17. BEHAVE: fire behavior prediction and fuel modeling system--FUEL subsystem

    Science.gov (United States)

    Robert E. Burgan; Richard C. Rothermel

    1984-01-01

    This manual documents the fuel modeling procedures of BEHAVE--a state-of-the-art wildland fire behavior prediction system. Described are procedures for collecting fuel data, using the data with the program, and testing and adjusting the fuel model.

  18. An Abstract Coalgebraic Approach to Process Equivalence for Well- Behaved Operational Semantics

    DEFF Research Database (Denmark)

    Klin, Bartek

    This thesis is part of the programme aimed at finding a mathematical theory of well-behaved structural operational semantics. General and basic results shown in 1997 in a seminal paper by Turi and Plotkin are extended in two directions, aiming at greater expressivity of the framework. The so-call...

  19. BEHAVE: fire behavior prediction and fuel modeling system-BURN Subsystem, part 1

    Science.gov (United States)

    Patricia L. Andrews

    1986-01-01

    Describes BURN Subsystem, Part 1, the operational fire behavior prediction subsystem of the BEHAVE fire behavior prediction and fuel modeling system. The manual covers operation of the computer program, assumptions of the mathematical models used in the calculations, and application of the predictions.

  20. A lightweight telemetry system for recording neuronal activity in freely behaving small animals

    NARCIS (Netherlands)

    Schregardus, D.S.; Pieneman, A.W.; ter Maat, A.; Brouwer, T.J.F.; Gahr, M.L.

    2006-01-01

    A miniature lightweight radio telemetric device is described which is shown to be suitable for recording neuronal activity in freely behaving animals. Its size (12 × 5 × 8 mm) and weight (1.0-1.1 g with batteries, 0.4-0.5 g without) make the device particularly suitable for recording neuronal units

  1. Spin Relaxation in III-V Semiconductors in various systems: Contribution of Electron-Electron Interaction

    Science.gov (United States)

    Dogan, Fatih; Kesserwan, Hasan; Manchon, Aurelien

    2015-03-01

    In spintronics, most of the phenomena that we are interested happen at very fast time scales and are rich in structure in time domain. Our understanding, on the other hand, is mostly based on energy domain calculations. Many of the theoretical tools use approximations and simplifications that can be perceived as oversimplifications. We compare the structure, material, carrier density and temperature dependence of spin relaxation time in n-doped III-V semiconductors using Elliot-Yafet (EY) and D'yakanov-Perel'(DP) with real time analysis using kinetic spin Bloch equations (KSBE). The EY and DP theories fail to capture details as the system investigated is varied. KSBE, on the other hand, incorporates all relaxation sources as well as electron-electron interaction which modifies the spin relaxation time in a non-linear way. Since el-el interaction is very fast (~ fs) and spin-conserving, it is usually ignored in the analysis of spin relaxation. Our results indicate that electron-electron interaction cannot be neglected and its interplay with the other (spin and momentum) relaxation mechanisms (electron-impurity and electron-phonon scattering) dramatically alters the resulting spin dynamics. We use each interaction explicitly to investigate how, in the presence of others, each relaxation source behaves. We use GaAs and GaN for zinc-blend structure, and GaN and AlN for the wurtzite structure.

  2. Effects of relaxation on psychobiological wellbeing during pregnancy: a randomized controlled trial.

    Science.gov (United States)

    Urech, Corinne; Fink, Nadine S; Hoesli, Irène; Wilhelm, Frank H; Bitzer, Johannes; Alder, Judith

    2010-10-01

    Prenatal maternal stress is associated with adverse birth outcomes and may be reduced by relaxation exercises. The aim of the present study was to compare the immediate effects of two active and one passive 10-min relaxation technique on perceived and physiological indicators of relaxation. 39 healthy pregnant women recruited at the outpatient department of the University Women's Hospital Basel participated in a randomized controlled trial with an experimental repeated measure design. Participants were assigned to one of two active relaxation techniques, progressive muscle relaxation (PMR) or guided imagery (GI), or a passive relaxation control condition. Self-reported relaxation on a visual analogue scale (VAS) and state anxiety (STAI-S), endocrine parameters indicating hypothalamic-pituitary-adrenal (HPA) axis (cortisol and ACTH) and sympathetic-adrenal-medullary (SAM) system activity (norepinephrine and epinephrine), as well as cardiovascular responses (heart rate, systolic and diastolic blood pressure) were measured at four time points before and after the relaxation exercise. Between group differences showed, that compared to the PMR and control conditions, GI was significantly more effective in enhancing levels of relaxation and together with PMR, GI was associated with a significant decrease in heart rate. Within the groups, passive as well as active relaxation procedures were associated with a decline in endocrine measures except epinephrine. Taken together, these data indicate that different types of relaxation had differential effects on various psychological and biological stress systems. GI was especially effective in inducing self-reported relaxation in pregnant women while at the same time reducing cardiovascular activity. Copyright © 2010 Elsevier Ltd. All rights reserved.

  3. Muscle Contraction.

    Science.gov (United States)

    Sweeney, H Lee; Hammers, David W

    2018-02-01

    SUMMARYMuscle cells are designed to generate force and movement. There are three types of mammalian muscles-skeletal, cardiac, and smooth. Skeletal muscles are attached to bones and move them relative to each other. Cardiac muscle comprises the heart, which pumps blood through the vasculature. Skeletal and cardiac muscles are known as striated muscles, because the filaments of actin and myosin that power their contraction are organized into repeating arrays, called sarcomeres, that have a striated microscopic appearance. Smooth muscle does not contain sarcomeres but uses the contraction of filaments of actin and myosin to constrict blood vessels and move the contents of hollow organs in the body. Here, we review the principal molecular organization of the three types of muscle and their contractile regulation through signaling mechanisms and discuss their major structural and functional similarities that hint at the possible evolutionary relationships between the cell types. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

  4. Longitudinal muscle dysfunction in achalasia esophagus and its relevance.

    Science.gov (United States)

    Mittal, Ravinder K; Hong, Su Jin; Bhargava, Valmik

    2013-04-01

    Muscularis propria of the esophagus is organized into circular and longitudinal muscle layers. Goal of this review is to summarize the role of longitudinal muscle in physiology and pathophysiology of esophageal sensory and motor function. Simultaneous manometry and ultrasound imaging that measure circular and longitudinal muscle contraction respectively reveal that during peristalsis 2 layers of the esophagus contract in perfect synchrony. On the other hand, during transient relaxation of the lower esophageal sphincter (LES), longitudinal muscle contracts independently of circular muscle. Recent studies provide novel insights, i.e., longitudinal muscle contraction of the esophagus induces LES relaxation and possibly descending relaxation of the esophagus. In achalasia esophagus and other motility disorders there is discoordination between the 2 muscle layers. Longitudinal muscle contraction patterns are different in the recently described three types of achalasia identified by high-resolution manometry. Robust contraction of the longitudinal muscle in type II achalasia causes pan-esophageal pressurization and is the mechanism of whatever little esophageal emptying that take place in the absence of peristalsis and impaired LES relaxation. It may be that preserved longitudinal muscle contraction is also the reason for superior outcome to medical/surgical therapy in type II achalasia esophagus. Prolonged contractions of longitudinal muscles of the esophagus is a possible mechanism of heartburn and "angina like" pain seen in esophageal motility disorders and possibly achalasia esophagus. Novel techniques to record longitudinal muscle contraction are on the horizon. Neuro-pharmacologic control of circular and longitudinal muscles is different, which provides an important opportunity for the development of novel pharmacological therapies to treat sensory and motor disorders of the esophagus.

  5. Bio-inspired Hybrid Carbon Nanotube Muscles

    Science.gov (United States)

    Kim, Tae Hyeob; Kwon, Cheong Hoon; Lee, Changsun; An, Jieun; Phuong, Tam Thi Thanh; Park, Sun Hwa; Lima, Márcio D.; Baughman, Ray H.; Kang, Tong Mook; Kim, Seon Jeong

    2016-05-01

    There has been continuous progress in the development for biomedical engineering systems of hybrid muscle generated by combining skeletal muscle and artificial structure. The main factor affecting the actuation performance of hybrid muscle relies on the compatibility between living cells and their muscle scaffolds during cell culture. Here, we developed a hybrid muscle powered by C2C12 skeletal muscle cells based on the functionalized multi-walled carbon nanotubes (MWCNT) sheets coated with poly(3,4-ethylenedioxythiophene) (PEDOT) to achieve biomimetic actuation. This hydrophilic hybrid muscle is physically durable in solution and responds to electric field stimulation with flexible movement. Furthermore, the biomimetic actuation when controlled by electric field stimulation results in movement similar to that of the hornworm by patterned cell culture method. The contraction and relaxation behavior of the PEDOT/MWCNT-based hybrid muscle is similar to that of the single myotube movement, but has faster relaxation kinetics because of the shape-maintenance properties of the freestanding PEDOT/MWCNT sheets in solution. Our development provides the potential possibility for substantial innovation in the next generation of cell-based biohybrid microsystems.

  6. Direct effects of doxorubicin on skeletal muscle contribute to fatigue

    NARCIS (Netherlands)

    Norren, van K.; Helvoort, van A.; Argiles, J.M.; Tuijl, van S.; Arts, K.; Gorselink, M.; Laviano, A.; Kegler, D.; Haagsman, H.P.; Beek, E.M.

    2009-01-01

    Chemotherapy-induced fatigue is a multidimensional symptom. Oxidative stress has been proposed as a working mechanism for anthracycline-induced cardiotoxicity. In this study, doxorubicin (DOX) was tested on skeletal muscle function. Doxorubicin induced impaired ex vivo skeletal muscle relaxation

  7. Peeling mode relaxation ELM model

    International Nuclear Information System (INIS)

    Gimblett, C. G.

    2006-01-01

    This paper discusses an approach to modelling Edge Localised Modes (ELMs) in which toroidal peeling modes are envisaged to initiate a constrained relaxation of the tokamak outer region plasma. Relaxation produces both a flattened edge current profile (which tends to further destabilise a peeling mode), and a plasma-vacuum negative current sheet which has a counteracting stabilising influence; the balance that is struck between these two effects determines the radial extent (rE) of the ELM relaxed region. The model is sensitive to the precise position of the mode rational surfaces to the plasma surface and hence there is a 'deterministic scatter' in the results that has an accord with experimental data. The toroidal peeling stability criterion involves the edge pressure, and using this in conjunction with predictions of rE allows us to evaluate the ELM energy losses and compare with experiment. Predictions of trends with the edge safety factor and collisionality are also made

  8. Exercise and relaxation intervention for patients with advanced lung cancer

    DEFF Research Database (Denmark)

    Adamsen, Lis; Stage, M; Laursen, J

    2012-01-01

    Lung cancer patients experience loss of physical capacity, dyspnea, pain, reduced energy and psychological distress. The aim of this study was to explore feasibility, health benefits and barriers of exercise in former sedentary patients with advanced stage lung cancer, non-small cell lung cancer...... (NSCLC) (III-IV) and small cell lung cancer (SCLC) (ED), undergoing chemotherapy. The intervention consisted of a hospital-based, supervised, group exercise and relaxation program comprising resistance-, cardiovascular- and relaxation training 4 h weekly, 6 weeks, and a concurrent unsupervised home......-based exercise program. An explorative study using individual semi-structured interviews (n=15) and one focus group interview (n=8) was conducted among the participants. Throughout the intervention the patients experienced increased muscle strength, improvement in wellbeing, breathlessness and energy. The group...

  9. History-dependence of muscle slack length following contraction and stretch in the human vastus lateralis.

    Science.gov (United States)

    Stubbs, Peter W; Walsh, Lee D; D'Souza, Arkiev; Héroux, Martin E; Bolsterlee, Bart; Gandevia, Simon C; Herbert, Robert D

    2018-06-01

    In reduced muscle preparations, the slack length and passive stiffness of muscle fibres have been shown to be influenced by previous muscle contraction or stretch. In human muscles, such behaviours have been inferred from measures of muscle force, joint stiffness and reflex magnitudes and latencies. Using ultrasound imaging, we directly observed that isometric contraction of the vastus lateralis muscle at short lengths reduces the slack lengths of the muscle-tendon unit and muscle fascicles. The effect is apparent 60 s after the contraction. These observations imply that muscle contraction at short lengths causes the formation of bonds which reduce the effective length of structures that generate passive tension in muscles. In reduced muscle preparations, stretch and muscle contraction change the properties of relaxed muscle fibres. In humans, effects of stretch and contraction on properties of relaxed muscles have been inferred from measurements of time taken to develop force, joint stiffness and reflex latencies. The current study used ultrasound imaging to directly observe the effects of stretch and contraction on muscle-tendon slack length and fascicle slack length of the human vastus lateralis muscle in vivo. The muscle was conditioned by (a) strong isometric contractions at long muscle-tendon lengths, (b) strong isometric contractions at short muscle-tendon lengths, (c) weak isometric contractions at long muscle-tendon lengths and (d) slow stretches. One minute after conditioning, ultrasound images were acquired from the relaxed muscle as it was slowly lengthened through its physiological range. The ultrasound image sequences were used to identify muscle-tendon slack angles and fascicle slack lengths. Contraction at short muscle-tendon lengths caused a mean 13.5 degree (95% CI 11.8-15.0 degree) shift in the muscle-tendon slack angle towards shorter muscle-tendon lengths, and a mean 5 mm (95% CI 2-8 mm) reduction in fascicle slack length, compared to the

  10. Longitudinal Muscle Dysfunction in Achalasia Esophagus and Its Relevance

    OpenAIRE

    Mittal, Ravinder K; Hong, Su Jin; Bhargava, Valmik

    2013-01-01

    Muscularis propria of the esophagus is organized into circular and longitudinal muscle layers. Goal of this review is to summarize the role of longitudinal muscle in physiology and pathophysiology of esophageal sensory and motor function. Simultaneous manometry and ultrasound imaging that measure circular and longitudinal muscle contraction respectively reveal that during peristalsis 2 layers of the esophagus contract in perfect synchrony. On the other hand, during transient relaxation of the...

  11. Combinatorial Clustering Algorithm of Quantum-Behaved Particle Swarm Optimization and Cloud Model

    Directory of Open Access Journals (Sweden)

    Mi-Yuan Shan

    2013-01-01

    Full Text Available We propose a combinatorial clustering algorithm of cloud model and quantum-behaved particle swarm optimization (COCQPSO to solve the stochastic problem. The algorithm employs a novel probability model as well as a permutation-based local search method. We are setting the parameters of COCQPSO based on the design of experiment. In the comprehensive computational study, we scrutinize the performance of COCQPSO on a set of widely used benchmark instances. By benchmarking combinatorial clustering algorithm with state-of-the-art algorithms, we can show that its performance compares very favorably. The fuzzy combinatorial optimization algorithm of cloud model and quantum-behaved particle swarm optimization (FCOCQPSO in vague sets (IVSs is more expressive than the other fuzzy sets. Finally, numerical examples show the clustering effectiveness of COCQPSO and FCOCQPSO clustering algorithms which are extremely remarkable.

  12. Evolving Models of Pavlovian Conditioning: Cerebellar Cortical Dynamics in Awake Behaving Mice

    Directory of Open Access Journals (Sweden)

    Michiel M. ten Brinke

    2015-12-01

    Full Text Available Three decades of electrophysiological research on cerebellar cortical activity underlying Pavlovian conditioning have expanded our understanding of motor learning in the brain. Purkinje cell simple spike suppression is considered to be crucial in the expression of conditional blink responses (CRs. However, trial-by-trial quantification of this link in awake behaving animals is lacking, and current hypotheses regarding the underlying plasticity mechanisms have diverged from the classical parallel fiber one to the Purkinje cell synapse LTD hypothesis. Here, we establish that acquired simple spike suppression, acquired conditioned stimulus (CS-related complex spike responses, and molecular layer interneuron (MLI activity predict the expression of CRs on a trial-by-trial basis using awake behaving mice. Additionally, we show that two independent transgenic mouse mutants with impaired MLI function exhibit motor learning deficits. Our findings suggest multiple cerebellar cortical plasticity mechanisms underlying simple spike suppression, and they implicate the broader involvement of the olivocerebellar module within the interstimulus interval.

  13. Relaxation properties in classical diamagnetism

    Science.gov (United States)

    Carati, A.; Benfenati, F.; Galgani, L.

    2011-06-01

    It is an old result of Bohr that, according to classical statistical mechanics, at equilibrium a system of electrons in a static magnetic field presents no magnetization. Thus a magnetization can occur only in an out of equilibrium state, such as that produced through the Foucault currents when a magnetic field is switched on. It was suggested by Bohr that, after the establishment of such a nonequilibrium state, the system of electrons would quickly relax back to equilibrium. In the present paper, we study numerically the relaxation to equilibrium in a modified Bohr model, which is mathematically equivalent to a billiard with obstacles, immersed in a magnetic field that is adiabatically switched on. We show that it is not guaranteed that equilibrium is attained within the typical time scales of microscopic dynamics. Depending on the values of the parameters, one has a relaxation either to equilibrium or to a diamagnetic (presumably metastable) state. The analogy with the relaxation properties in the Fermi Pasta Ulam problem is also pointed out.

  14. Onsager relaxation of toroidal plasmas

    International Nuclear Information System (INIS)

    Samain, A.; Nguyen, F.

    1997-01-01

    The slow relaxation of isolated toroidal plasmas towards their thermodynamical equilibrium is studied in an Onsager framework based on the entropy metric. The basic tool is a variational principle, equivalent to the kinetic equation, involving the profiles of density, temperature, electric potential, electric current. New minimization procedures are proposed to obtain entropy and entropy production rate functionals. (author)

  15. Anisotropic spin relaxation in graphene

    NARCIS (Netherlands)

    Tombros, N.; Tanabe, S.; Veligura, A.; Jozsa, C.; Popinciuc, M.; Jonkman, H. T.; van Wees, B. J.

    2008-01-01

    Spin relaxation in graphene is investigated in electrical graphene spin valve devices in the nonlocal geometry. Ferromagnetic electrodes with in-plane magnetizations inject spins parallel to the graphene layer. They are subject to Hanle spin precession under a magnetic field B applied perpendicular

  16. Stochastic and Chaotic Relaxation Oscillations

    NARCIS (Netherlands)

    Grasman, J.; Roerdink, J.B.T.M.

    1988-01-01

    For relaxation oscillators stochastic and chaotic dynamics are investigated. The effect of random perturbations upon the period is computed. For an extended system with additional state variables chaotic behavior can be expected. As an example, the Van der Pol oscillator is changed into a

  17. Tensions relaxation in Zircaloy-4

    International Nuclear Information System (INIS)

    Cuniberti, A.M.; Picasso, A.C.

    1990-01-01

    Traction and stress relaxation studies were performed on polycrystalline Zry-4 at room temperature. The effect of loading velocity on the plastic behaviour of the material is discussed, analysing log σ vs. log dε/dt at different deformation levels. The contribution introduced by the testing machine was taken into account in data evaluation. (Author). 7 refs., 3 figs., 3 tabs

  18. Do Students Behave Rationally in Multiple Choice Tests? Evidence from a Field Experiment

    OpenAIRE

    María Paz Espinosa; Javier Gardeazabal

    2013-01-01

    A disadvantage of multiple choice tests is that students have incentives to guess. To discourage guessing, it is common to use scoring rules that either penalize wrong answers or reward omissions. In psychometrics, penalty and reward scoring rules are considered equivalent. However, experimental evidence indicates that students behave differently under penalty or reward scoring rules. These differences have been attributed to the different framing (penalty versus reward). In this paper, we mo...

  19. Chaos Quantum-Behaved Cat Swarm Optimization Algorithm and Its Application in the PV MPPT

    Directory of Open Access Journals (Sweden)

    Xiaohua Nie

    2017-01-01

    Full Text Available Cat Swarm Optimization (CSO algorithm was put forward in 2006. Despite a faster convergence speed compared with Particle Swarm Optimization (PSO algorithm, the application of CSO is greatly limited by the drawback of “premature convergence,” that is, the possibility of trapping in local optimum when dealing with nonlinear optimization problem with a large number of local extreme values. In order to surmount the shortcomings of CSO, Chaos Quantum-behaved Cat Swarm Optimization (CQCSO algorithm is proposed in this paper. Firstly, Quantum-behaved Cat Swarm Optimization (QCSO algorithm improves the accuracy of the CSO algorithm, because it is easy to fall into the local optimum in the later stage. Chaos Quantum-behaved Cat Swarm Optimization (CQCSO algorithm is proposed by introducing tent map for jumping out of local optimum in this paper. Secondly, CQCSO has been applied in the simulation of five different test functions, showing higher accuracy and less time consumption than CSO and QCSO. Finally, photovoltaic MPPT model and experimental platform are established and global maximum power point tracking control strategy is achieved by CQCSO algorithm, the effectiveness and efficiency of which have been verified by both simulation and experiment.

  20. Chaos Quantum-Behaved Cat Swarm Optimization Algorithm and Its Application in the PV MPPT.

    Science.gov (United States)

    Nie, Xiaohua; Wang, Wei; Nie, Haoyao

    2017-01-01

    Cat Swarm Optimization (CSO) algorithm was put forward in 2006. Despite a faster convergence speed compared with Particle Swarm Optimization (PSO) algorithm, the application of CSO is greatly limited by the drawback of "premature convergence," that is, the possibility of trapping in local optimum when dealing with nonlinear optimization problem with a large number of local extreme values. In order to surmount the shortcomings of CSO, Chaos Quantum-behaved Cat Swarm Optimization (CQCSO) algorithm is proposed in this paper. Firstly, Quantum-behaved Cat Swarm Optimization (QCSO) algorithm improves the accuracy of the CSO algorithm, because it is easy to fall into the local optimum in the later stage. Chaos Quantum-behaved Cat Swarm Optimization (CQCSO) algorithm is proposed by introducing tent map for jumping out of local optimum in this paper. Secondly, CQCSO has been applied in the simulation of five different test functions, showing higher accuracy and less time consumption than CSO and QCSO. Finally, photovoltaic MPPT model and experimental platform are established and global maximum power point tracking control strategy is achieved by CQCSO algorithm, the effectiveness and efficiency of which have been verified by both simulation and experiment.

  1. An Adaptive Cultural Algorithm with Improved Quantum-behaved Particle Swarm Optimization for Sonar Image Detection.

    Science.gov (United States)

    Wang, Xingmei; Hao, Wenqian; Li, Qiming

    2017-12-18

    This paper proposes an adaptive cultural algorithm with improved quantum-behaved particle swarm optimization (ACA-IQPSO) to detect the underwater sonar image. In the population space, to improve searching ability of particles, iterative times and the fitness value of particles are regarded as factors to adaptively adjust the contraction-expansion coefficient of the quantum-behaved particle swarm optimization algorithm (QPSO). The improved quantum-behaved particle swarm optimization algorithm (IQPSO) can make particles adjust their behaviours according to their quality. In the belief space, a new update strategy is adopted to update cultural individuals according to the idea of the update strategy in shuffled frog leaping algorithm (SFLA). Moreover, to enhance the utilization of information in the population space and belief space, accept function and influence function are redesigned in the new communication protocol. The experimental results show that ACA-IQPSO can obtain good clustering centres according to the grey distribution information of underwater sonar images, and accurately complete underwater objects detection. Compared with other algorithms, the proposed ACA-IQPSO has good effectiveness, excellent adaptability, a powerful searching ability and high convergence efficiency. Meanwhile, the experimental results of the benchmark functions can further demonstrate that the proposed ACA-IQPSO has better searching ability, convergence efficiency and stability.

  2. A charged anisotropic well-behaved Adler-Finch-Skea solution satisfying Karmarkar condition

    Science.gov (United States)

    Bhar, Piyali; Singh, Ksh. Newton; Rahaman, Farook; Pant, Neeraj; Banerjee, Sumita

    In the present paper, we discover a new well-behaved charged anisotropic solution of Einstein-Maxwell’s field equations. We ansatz the metric potential g00 of the form given by Maurya et al. (Eur. Phys. J. C 76(12) (2016) 693) with n = 2. In their paper, it is mentioned that for n = 2, the solution is not well-behaved for neutral configuration as the speed of sound is nondecreasing radially outward. However, the solution can represent a physically possible configuration with the inclusion of some net electric charge, i.e. the solution can become a well-behaved solution with decreasing sound speed radially outward for a charged configuration. Due to the inclusion of electric charge, the solution leads to a very stiff equation-of-state (EoS) with the velocity of sound at the center vr02 = 0.819, vt02 = 0.923 and the compactness parameter u = 0.823 is close to the Buchdahl limit 0.889. This stiff EoS support a compact star configuration of mass 5.418M⊙ and radius of 10.1km.

  3. Artificial muscle: facts and fiction.

    Science.gov (United States)

    Schaub, Marcus C

    2011-12-19

    Mechanical devices are sought to support insufficient or paralysed striated muscles including the failing heart. Nickel-titanium alloys (nitinol) present the following two properties: (i) super-elasticity, and (ii) the potential to assume different crystal structures depending on temperature and/or stress. Starting from the martensite state nitinol is able to resume the austenite form (state of low potential energy and high entropy) even against an external resistance. This one-way shape change is deployed in self-expanding vascular stents. Heating induces the force generating transformation from martensite to the austenite state while cooling induces relaxation back to the martensite state. This two-way shape change oscillating between the two states may be used in cyclically contracting support devices of silicon-coated nitinol wires. Such a contractile device sutured to the right atrium has been tested in vitro in a bench model and in vivo in sheep. The contraction properties of natural muscles, specifically of the myocardium, and the tight correlation with ATP production by oxidative phosphorylation in the mitochondria is briefly outlined. Force development by the nitinol device cannot be smoothly regulated as in natural muscle. Its mechanical impact is forced onto the natural muscle regardless of the actual condition with regard to metabolism and Ca2+-homeostasis. The development of artificial muscle on the basis of nitinol wires is still in its infancy. The nitinol artificial muscle will have to prove its viability in the various clinical settings.

  4. The Role of Regular Home Practice in the Relaxation Treatment of Tension Headache.

    Science.gov (United States)

    Blanchard, Edward B.; And Others

    1991-01-01

    Gave 27 tension headache sufferers progressive muscle relaxation (PMR) training, with 14 of those subjects also receiving home practice and application instructions. Compared to third group of sufferers (n=6) who merely monitored headache activity, both treated groups showed significant reduction in headache activity. Treatment groups did not…

  5. The Relaxant Effect of Seed's Essential Oil and Oleo‑gum‑resin of ...

    African Journals Online (AJOL)

    kenchu‑to on spontaneous activity in the mouse small intestine. J Smooth Muscle Res. 2006;42:189‑201. 17. Gholamnezhad Z, Byrami G, Boskabady MH, Iranshahi M. Possible mechanism (s) of the relaxant effect of asafoetida. (Ferula assa‑foetida) ...

  6. The Effect of Relaxation Interventions on Cortisol Levels in HIV-Sero-Positive Women

    Science.gov (United States)

    Jones, Deborah; Owens, Mary; Kumar, Mahendra; Cook, Ryan; Weiss, Stephen M.

    2016-01-01

    Purpose Activation of the hypothalamic–pituitary–adrenal axis, assessed in terms of cortisol levels, may enhance the ability of HIV to infect lymphocytes and downregulate the immune system, accelerating disease progression. This study sought to determine the effects of relaxation techniques on cortisol levels in HIV-sero-positive women. Methods Women (n = 150) were randomized to a group cognitive–behavioral stress management (CBSM) condition or an individual information condition and underwent 3 types of relaxation training (progressive muscle relaxation, imagery, and autogenic training). Cortisol levels were obtained pre- and postrelaxation. Results Guided imagery was effective in reducing cortisol in the group condition (t = 3.90, P < .001), and muscle relaxation reduced cortisol in the individual condition (t = 3.11, P = .012). Among participants in the group condition attending all sessions, the magnitude of pre- to postsession reduction became greater over time. Conclusions Results suggest that specific relaxation techniques may be partially responsible for cortisol decreases associated with relaxation and CBSM. PMID:23715264

  7. Muscle contraction analysis with MRI image

    International Nuclear Information System (INIS)

    Horio, Hideyuki; Kuroda, Yoshihiro; Imura, Masataka; Oshiro, Osamu

    2010-01-01

    The MRI measurement has been widely used from the advantage such as no radiation exposure and high resolution. In various measurement objects, the muscle is used for a research and clinical practice. But it was difficult to judge static state of a muscle contraction. In this study, we focused on a proton density change by the blood vessel pressure at the time of the muscle contraction, and aimed the judgments of muscle contraction from variance of the signal intensity. First, the background was removed from the measured images. Second, each signal divided into the low signal side and the high signal side, and variance values (σ H , σ L ) and the ratio (μ) were calculated. Finally, Relax and strain state ware judged from the ratio (μ). As a Result, in relax state, ratio (μ r ) was 0.9823±0.06133. And in strain state, ratio (μ s ) was 0.7547±0.10824. Therefore, a significant difference was obtained in relax state and strain state. Therefore, the strain state judgment of the muscle was possible by this study's method. (author)

  8. Biofeedback-assisted relaxation training to decrease test anxiety in nursing students.

    Science.gov (United States)

    Prato, Catherine A; Yucha, Carolyn B

    2013-01-01

    Nursing students experiencing debilitating test anxiety may be unable to demonstrate their knowledge and have potential for poor academic performance. A biofeedback-assisted relaxation training program was created to reduce test anxiety. Anxiety was measured using Spielberger's Test Anxiety Inventory and monitoring peripheral skin temperature, pulse, and respiration rates during the training. Participants were introduced to diaphragmatic breathing, progressive muscle relaxation, and autogenic training. Statistically significant changes occurred in respiratory rates and skin temperatures during the diaphragmatic breathing session; respiratory rates and peripheral skin temperatures during progressive muscle relaxation session; respiratory and pulse rates, and peripheral skin temperatures during the autogenic sessions. No statistically significant difference was noted between the first and second TAI. Subjective test anxiety scores of the students did not decrease by the end of training. Autogenic training session was most effective in showing a statistically significant change in decreased respiratory and pulse rates and increased peripheral skin temperature.

  9. Your Muscles

    Science.gov (United States)

    ... and you need to throw up. The muscles push the food back out of the stomach so it comes up ... body the power it needs to lift and push things. Muscles in your neck and the top part of your back aren't as large, but they are capable ...

  10. Theory of relaxation phenomena in a spin-3/2 Ising system near the second-order phase transition temperature

    International Nuclear Information System (INIS)

    Keskin, Mustafa; Canko, Osman

    2005-01-01

    The relaxation behavior of the spin-3/2 Ising model Hamiltonian with bilinear and biquadratic interactions near the second-order phase transition temperature or critical temperature is studied by means of the Onsager's theory of irreversible thermodynamics or the Onsager reciprocity theorem (ORT). First, we give the equilibrium case briefly within the molecular-field approximation in order to study the relaxation behavior by using the ORT. Then, the ORT is applied to the model and the kinetic equations are obtained. By solving these equations, three relaxation times are calculated and examined for temperatures near the second-order phase transition temperature. It is found that one of the relaxation times goes to infinity near the critical temperature on either side, the second relaxation time makes a cusp at the critical temperature and third one behaves very differently in which it terminates at the critical temperature while approaching it, then showing a 'flatness' property and then decreases. We also study the influences of the Onsager rate coefficients on the relaxation times. The behavior of these relaxation times is discussed and compared with the spin-1/2 and spin-1 Ising systems

  11. Relaxation and Distraction in Experimental Desensitization.

    Science.gov (United States)

    Weir, R. O.; Marshall, W. L.

    1980-01-01

    Compared experimental desensitization with a procedure that replaced relaxation with a distraction task and with an approach that combined both relaxation and distraction. Desensitization generally was more effective than the other two procedures. (Author)

  12. Relaxation as a Factor in Semantic Desensitization

    Science.gov (United States)

    Bechtel, James E.; McNamara, J. Regis

    1975-01-01

    Relaxation and semantic desensitization were used to alleviate the fear of phobic females. Results showed that semantic desensitization, alone or in combination with relaxation, failed to modify the evaluative meanings evoked by the feared object. (SE)

  13. Plasmon-mediated energy relaxation in graphene

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, D. K. [School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287-5706 (United States); Somphonsane, R. [Department of Physics, King Mongkut' s Institute of Technology, Ladkrabang, Bangkok 10520 (Thailand); Ramamoorthy, H.; Bird, J. P. [Department of Electrical Engineering, University at Buffalo, the State University of New York, Buffalo, New York 14260-1500 (United States)

    2015-12-28

    Energy relaxation of hot carriers in graphene is studied at low temperatures, where the loss rate may differ significantly from that predicted for electron-phonon interactions. We show here that plasmons, important in the relaxation of energetic carriers in bulk semiconductors, can also provide a pathway for energy relaxation in transport experiments in graphene. We obtain a total loss rate to plasmons that results in energy relaxation times whose dependence on temperature and density closely matches that found experimentally.

  14. Influence of pudendal nerve blockade on stress relaxation in the female urethra

    DEFF Research Database (Denmark)

    Thind, P; Bagi, P; Mieszczak, C

    1996-01-01

    The urethral pressure decay following a sudden and sustained dilatation corresponds to stress relaxation. Urethral stress relaxation can be described by the equation Pt = Pequ + P alpha e-t/tau alpha + P beta e-t/tau beta, where Pt is the pressure at time t, Pequ is the equilibrium pressure after...... dilatation, P alpha and P beta are pressure decay, and tau alpha and tau beta are time constants. The time constants have previously proved independent of the way the dilatation is performed. The urethral stress relaxation obtained in 10 healthy women before and after pudendal nerve blockade was analysed...... by the mathematical model and the pressure parameters and time constants determined. The fast time constant, tau beta, was reduced by the nerve blockade, whereas tau alpha was unaffected, however, both P alpha and P beta were reduced. No single stress relaxation parameter can therefore be related to the muscle...

  15. Nonlinear Relaxation in Population Dynamics

    Science.gov (United States)

    Cirone, Markus A.; de Pasquale, Ferdinando; Spagnolo, Bernardo

    We analyze the nonlinear relaxation of a complex ecosystem composed of many interacting species. The ecological system is described by generalized Lotka-Volterra equations with a multiplicative noise. The transient dynamics is studied in the framework of the mean field theory and with random interaction between the species. We focus on the statistical properties of the asymptotic behaviour of the time integral of the ith population and on the distribution of the population and of the local field.

  16. Structural relaxation: low temperature properties

    International Nuclear Information System (INIS)

    Cruz, F. de la

    1984-01-01

    We discuss the changes in transport and superconducting properties of amorphous Zr 70 Cu 30 , induced by thermal relaxation. The experimental results are used to investigate the relation between the microscopic parameters and the observed physical properties. It is shown that the density of eletronic states determines the shift Tc as well as the variation of the electrical resistivity. It is necessary to assume strong hybridization between s and d bands to understand the eletrodynamic response of the superconductor. (Author) [pt

  17. Biceps brachii muscle oxygenation in electrical muscle stimulation.

    Science.gov (United States)

    Muthalib, Makii; Jubeau, Marc; Millet, Guillaume Y; Maffiuletti, Nicola A; Ferrari, Marco; Nosaka, Kazunori

    2010-09-01

    The purpose of this study was to compare between electrical muscle stimulation (EMS) and maximal voluntary (VOL) isometric contractions of the elbow flexors for changes in biceps brachii muscle oxygenation (tissue oxygenation index, TOI) and haemodynamics (total haemoglobin volume, tHb = oxygenated-Hb + deoxygenated-Hb) determined by near-infrared spectroscopy (NIRS). The biceps brachii muscle of 10 healthy men (23-39 years) was electrically stimulated at high frequency (75 Hz) via surface electrodes to evoke 50 intermittent (4-s contraction, 15-s relaxation) isometric contractions at maximum tolerated current level (EMS session). The contralateral arm performed 50 intermittent (4-s contraction, 15-s relaxation) maximal voluntary isometric contractions (VOL session) in a counterbalanced order separated by 2-3 weeks. Results indicated that although the torque produced during EMS was approximately 50% of VOL (P<0.05), there was no significant difference in the changes in TOI amplitude or TOI slope between EMS and VOL over the 50 contractions. However, the TOI amplitude divided by peak torque was approximately 50% lower for EMS than VOL (P<0.05), which indicates EMS was less efficient than VOL. This seems likely because of the difference in the muscles involved in the force production between conditions. Mean decrease in tHb amplitude during the contraction phases was significantly (P<0.05) greater for EMS than VOL from the 10th contraction onwards, suggesting that the muscle blood volume was lower in EMS than VOL. It is concluded that local oxygen demand of the biceps brachii sampled by NIRS is similar between VOL and EMS.

  18. The Effects of Suggestibility on Relaxation.

    Science.gov (United States)

    Rickard, Henry C.; And Others

    1985-01-01

    Selected undergraduates (N=32) on the basis of Creative Imagination Scale scores and randomly assigned high and low suggestibility subjects to progressive relaxation (PR) and suggestions of relaxation (SR) training modes. Results revealed a significant pre-post relaxation effect, and main efffects for both suggestibility and training mode. (NRB)

  19. Relaxed Poisson cure rate models.

    Science.gov (United States)

    Rodrigues, Josemar; Cordeiro, Gauss M; Cancho, Vicente G; Balakrishnan, N

    2016-03-01

    The purpose of this article is to make the standard promotion cure rate model (Yakovlev and Tsodikov, ) more flexible by assuming that the number of lesions or altered cells after a treatment follows a fractional Poisson distribution (Laskin, ). It is proved that the well-known Mittag-Leffler relaxation function (Berberan-Santos, ) is a simple way to obtain a new cure rate model that is a compromise between the promotion and geometric cure rate models allowing for superdispersion. So, the relaxed cure rate model developed here can be considered as a natural and less restrictive extension of the popular Poisson cure rate model at the cost of an additional parameter, but a competitor to negative-binomial cure rate models (Rodrigues et al., ). Some mathematical properties of a proper relaxed Poisson density are explored. A simulation study and an illustration of the proposed cure rate model from the Bayesian point of view are finally presented. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Arresting relaxation in Pickering Emulsions

    Science.gov (United States)

    Atherton, Tim; Burke, Chris

    2015-03-01

    Pickering emulsions consist of droplets of one fluid dispersed in a host fluid and stabilized by colloidal particles absorbed at the fluid-fluid interface. Everyday materials such as crude oil and food products like salad dressing are examples of these materials. Particles can stabilize non spherical droplet shapes in these emulsions through the following sequence: first, an isolated droplet is deformed, e.g. by an electric field, increasing the surface area above the equilibrium value; additional particles are then adsorbed to the interface reducing the surface tension. The droplet is then allowed to relax toward a sphere. If more particles were adsorbed than can be accommodated by the surface area of the spherical ground state, relaxation of the droplet is arrested at some non-spherical shape. Because the energetic cost of removing adsorbed colloids exceeds the interfacial driving force, these configurations can remain stable over long timescales. In this presentation, we present a computational study of the ordering present in anisotropic droplets produced through the mechanism of arrested relaxation and discuss the interplay between the geometry of the droplet, the dynamical process that produced it, and the structure of the defects observed.

  1. Vibrational relaxation in OCS mixtures

    International Nuclear Information System (INIS)

    Simpson, C.J.S.M.; Gait, P.D.; Simmie, J.M.

    1976-01-01

    Experimental measurements are reported of vibrational relaxation times which may be used to show whether there is near resonant vibration-rotation energy transfer between OCS and H 2 , D 2 or HD. Vibrational relaxation times have been measured in OCS and OCS mixtures over the temperature range 360 to 1000 K using a shock tube and a laser schlieren system. The effectiveness of the additives in reducing the relaxation time of OCS is in the order 4 He 3 He 2 2 and HD. Along this series the effect of an increase in temperature changes from the case of speeding up the rate with 4 He to retarding it with D 2 , HD and H 2 . There is no measurable difference in the effectiveness of n-D 2 and o-D 2 and little, or no, difference between n-H 2 and p-H 2 . Thus the experimental results do not give clear evidence for rotational-vibration energy transfer between hydrogen and OCS. This contrasts with the situation for CO 2 + H 2 mixtures. (author)

  2. Relaxed plasma-vacuum systems

    International Nuclear Information System (INIS)

    Spies, G.O.; Lortz, D.; Kaiser, R.

    2001-01-01

    Taylor's theory of relaxed toroidal plasmas (states of lowest energy with fixed total magnetic helicity) is extended to include a vacuum between the plasma and the wall. In the extended variational problem, one prescribes, in addition to the helicity and the magnetic fluxes whose conservation follows from the perfect conductivity of the wall, the fluxes whose conservation follows from the assumption that the plasma-vacuum interface is also perfectly conducting (if the wall is a magnetic surface, then one has the toroidal and the poloidal flux in the vacuum). Vanishing of the first energy variation implies a pressureless free-boundary magnetohydrostatic equilibrium with a Beltrami magnetic field in the plasma, and in general with a surface current in the interface. Positivity of the second variation implies that the equilibrium is stable according to ideal magnetohydrodynamics, that it is a relaxed state according to Taylor's theory if the interface is replaced by a wall, and that the surface current is nonzero (at least if there are no closed magnetic field lines in the interface). The plane slab, with suitable boundary conditions to simulate a genuine torus, is investigated in detail. The relaxed state has the same double symmetry as the vessel if, and only if, the prescribed helicity is in an interval that depends on the prescribed fluxes. This interval is determined in the limit of a thin slab

  3. Regularized Label Relaxation Linear Regression.

    Science.gov (United States)

    Fang, Xiaozhao; Xu, Yong; Li, Xuelong; Lai, Zhihui; Wong, Wai Keung; Fang, Bingwu

    2018-04-01

    Linear regression (LR) and some of its variants have been widely used for classification problems. Most of these methods assume that during the learning phase, the training samples can be exactly transformed into a strict binary label matrix, which has too little freedom to fit the labels adequately. To address this problem, in this paper, we propose a novel regularized label relaxation LR method, which has the following notable characteristics. First, the proposed method relaxes the strict binary label matrix into a slack variable matrix by introducing a nonnegative label relaxation matrix into LR, which provides more freedom to fit the labels and simultaneously enlarges the margins between different classes as much as possible. Second, the proposed method constructs the class compactness graph based on manifold learning and uses it as the regularization item to avoid the problem of overfitting. The class compactness graph is used to ensure that the samples sharing the same labels can be kept close after they are transformed. Two different algorithms, which are, respectively, based on -norm and -norm loss functions are devised. These two algorithms have compact closed-form solutions in each iteration so that they are easily implemented. Extensive experiments show that these two algorithms outperform the state-of-the-art algorithms in terms of the classification accuracy and running time.

  4. Simulating the activation, contraction and movement of skeletal muscles using the bidomain model.

    Science.gov (United States)

    Lopez Rincon, A; Cantu, C; Soto, R; Shimoda, S

    2016-08-01

    A simulation of the muscle activation, contraction and movement is here presented. This system was developed based on the Bidomain mathematical model of the electrical propagation in muscles. This study shows an electrical stimuli input to a muscle and how this behave. The comparison between healthy subject and patient with muscle activation impairment is depicted, depending on whether the signal reaches a threshold. A 3D model of a bicep muscle and a forearm bone connected was constructed using OpenGL. This platform could be used for development of controllers for biomechatronic systems in future works. This kind of bioinspired model could be used for a better understanding of the neuromotor system.

  5. Optimal duration of ultra low frequency-transcutaneous electrical nerve stimulation (ULF-TENS) therapy for muscular relaxation in neuromuscular occlusion: A preliminary clinical study.

    Science.gov (United States)

    Esclassan, Rémi; Rumerio, Anaïs; Monsarrat, Paul; Combadazou, Jean Claude; Champion, Jean; Destruhaut, Florent; Ghrenassia, Christophe

    2017-05-01

    The primary aim of this work was to determine the duration of ultra-low-frequency transcutaneous electrical nerve stimulation (ULF-TENS) application necessary to achieve sufficient relaxation of the masticatory muscles. A secondary aim was to analyze the influence of stimulation on muscle relaxation in pathological subjects and determine whether ULF-TENS has a noteworthy impact on muscle relaxation. Sixteen adult subjects with temporomandibular disorders (TMD) and muscle pain and a group of four control subjects were included in this study. ULF-TENS was applied, and muscular activities of the masseter, temporal, and sternocleidomastoid muscles (SCM) were recorded for 60 min. Significant relaxation was achieved in the TMD group from 20, 40, and 60 min for the temporal, masseter, and SCM muscles (p TENS application would last 40 min to obtain sufficient muscle relaxation both in patients with masticatory system disorders and healthy subjects, a time constraint that is consistent with everyday clinical practice.

  6. Solving Bilevel Multiobjective Programming Problem by Elite Quantum Behaved Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Tao Zhang

    2012-01-01

    Full Text Available An elite quantum behaved particle swarm optimization (EQPSO algorithm is proposed, in which an elite strategy is exerted for the global best particle to prevent premature convergence of the swarm. The EQPSO algorithm is employed for solving bilevel multiobjective programming problem (BLMPP in this study, which has never been reported in other literatures. Finally, we use eight different test problems to measure and evaluate the proposed algorithm, including low dimension and high dimension BLMPPs, as well as attempt to solve the BLMPPs whose theoretical Pareto optimal front is not known. The experimental results show that the proposed algorithm is a feasible and efficient method for solving BLMPPs.

  7. A simple miniature device for wireless stimulation of neural circuits in small behaving animals.

    Science.gov (United States)

    Zhang, Yisi; Langford, Bruce; Kozhevnikov, Alexay

    2011-10-30

    The use of wireless neural stimulation devices offers significant advantages for neural stimulation experiments in behaving animals. We demonstrate a simple, low-cost and extremely lightweight wireless neural stimulation device which is made from off-the-shelf components. The device has low power consumption and does not require a high-power RF preamplifier. Neural stimulation can be carried out in either a voltage source mode or a current source mode. Using the device, we carry out wireless stimulation in the premotor brain area HVC of a songbird and demonstrate that such stimulation causes rapid perturbations of the acoustic structure of the song. Published by Elsevier B.V.

  8. Pareto-Ranking Based Quantum-Behaved Particle Swarm Optimization for Multiobjective Optimization

    Directory of Open Access Journals (Sweden)

    Na Tian

    2015-01-01

    Full Text Available A study on pareto-ranking based quantum-behaved particle swarm optimization (QPSO for multiobjective optimization problems is presented in this paper. During the iteration, an external repository is maintained to remember the nondominated solutions, from which the global best position is chosen. The comparison between different elitist selection strategies (preference order, sigma value, and random selection is performed on four benchmark functions and two metrics. The results demonstrate that QPSO with preference order has comparative performance with sigma value according to different number of objectives. Finally, QPSO with sigma value is applied to solve multiobjective flexible job-shop scheduling problems.

  9. A novel fiber-free technique for brain activity imaging in multiple freely behaving mice

    Science.gov (United States)

    Inagaki, Shigenori; Agetsuma, Masakazu; Nagai, Takeharu

    2018-02-01

    Brain functions and related psychiatric disorders have been investigated by recording electrophysiological field potential. When recording it, a conventional method requires fiber-based apparatus connected to the brain, which however hampers the simultaneous measurement in multiple animals (e.g. by a tangle of fibers). Here, we propose a fiber-free recording technique in conjunction with a ratiometric bioluminescent voltage indicator. Our method allows investigation of electrophysiological filed potential dynamics in multiple freely behaving animals simultaneously over a long time period. Therefore, this fiber-free technique opens up the way to investigate a new mechanism of brain function that governs social behaviors and animal-to-animal interaction.

  10. Capturing molecular multimode relaxation processes in excitable gases based on decomposition of acoustic relaxation spectra

    Science.gov (United States)

    Zhu, Ming; Liu, Tingting; Wang, Shu; Zhang, Kesheng

    2017-08-01

    Existing two-frequency reconstructive methods can only capture primary (single) molecular relaxation processes in excitable gases. In this paper, we present a reconstructive method based on the novel decomposition of frequency-dependent acoustic relaxation spectra to capture the entire molecular multimode relaxation process. This decomposition of acoustic relaxation spectra is developed from the frequency-dependent effective specific heat, indicating that a multi-relaxation process is the sum of the interior single-relaxation processes. Based on this decomposition, we can reconstruct the entire multi-relaxation process by capturing the relaxation times and relaxation strengths of N interior single-relaxation processes, using the measurements of acoustic absorption and sound speed at 2N frequencies. Experimental data for the gas mixtures CO2-N2 and CO2-O2 validate our decomposition and reconstruction approach.

  11. Sandpile model for relaxation in complex systems

    International Nuclear Information System (INIS)

    Vazquez, A.; Sotolongo-Costa, O.; Brouers, F.

    1997-10-01

    The relaxation in complex systems is, in general, nonexponential. After an initial rapid decay the system relaxes slowly following a long time tail. In the present paper a sandpile moderation of the relaxation in complex systems is analysed. Complexity is introduced by a process of avalanches in the Bethe lattice and a feedback mechanism which leads to slower decay with increasing time. In this way, some features of relaxation in complex systems: long time tails relaxation, aging, and fractal distribution of characteristic times, are obtained by simple computer simulations. (author)

  12. Muscle cramps

    Science.gov (United States)

    ... the lower leg/calf Back of the thigh (hamstrings) Front of the thigh (quadriceps) Cramps in the ... Names Cramps - muscle Images Chest stretch Groin stretch Hamstring stretch Hip stretch Thigh stretch Triceps stretch References ...

  13. Muscle atrophy

    Science.gov (United States)

    ... People who cannot actively move one or more joints can do exercises using braces or splints . When ... A.M. Editorial team. Muscle Disorders Read more Neuromuscular Disorders Read more NIH MedlinePlus Magazine Read more ...

  14. [Variation of muscle mass and weight in critical patient].

    Science.gov (United States)

    Valls-Matarín, J; del Cotillo-Fuente, M; Grané-Mascarell, N; Quintana, S

    2015-01-01

    Quantify the muscle mass and body weight variation in critically ill patients and to identify associated factors. A descriptive follow-up study. Data for demographic variables, body weight, fluid balance, daily kilocalories, the amount of sedation and muscle relaxants received and motor physiotherapy applied were collected. Three consecutive measurements were performed in the brachial biceps and quadriceps rectus by using ultrasound, upon admission and every 5 days until discharge. 68 patients were included. Average age was of 73.5 [57-78,5] years. The median length of stay was 9.5 [5.5 -15] days. The median 16 (SD=5.7) daily kilocalories per kg/weight, 91.2% received sedation, 44.1% received muscle relaxants and 20% received physiotherapy. The patients presented a muscle wasting of 4.9 (SD=3.9)mm, p <.001 in the brachial biceps and 5.6 (SD=4.8)mm, p <.001 in the quadriceps rectus. Regression analysis selected the length of stay and the muscle relaxants are the most influential variables in the brachial biceps muscle wasting (R2=0.4), and length of stay as the most influential in the quadriceps rectus muscle wasting (R2=0.3). Patient's mean body weight on admission was of 81.1 (SD=15)kg and 81.2 (SD=14.2)kg on discharge, p=.95. The critically ill patient presents a significant muscle waste related with the length of stay and the treatment received with muscle relaxants. Patients are being discharged with a similar body weight to which they were admitted but with a significant reduction of muscle mass. Copyright © 2014 Elsevier España, S.L.U. y SEEIUC. All rights reserved.

  15. Nitrergic Pathway Is the Main Contributing Mechanism in the Human Gastric Fundus Relaxation: An In Vitro Study.

    Directory of Open Access Journals (Sweden)

    Yang Won Min

    Full Text Available Human gastric fundus relaxation is mediated by intrinsic inhibitory pathway. We investigated the roles of nitrergic and purinergic pathways, two known inhibitory factors in gastric motility, on spontaneous and nerve-evoked contractions in human gastric fundus muscles.Gastric fundus muscle strips (12 circular and 13 longitudinal were obtained from patients without previous gastrointestinal motility disorder who underwent gastrectomy for stomach cancer. Using these specimens, we examined basal tone, peak, amplitude, and frequency of spontaneous contractions, and peak and nadir values under electrical field stimulation (EFS, 150 V, 0.3 ms, 10 Hz, 20 s. To examine responses to purinergic and nitrergic inhibition without cholinergic innervation, atropine (muscarinic antagonist, 1 μM, MRS2500 (a purinergic P2Y1 receptor antagonist, 1 μM, and N-nitro-L-arginine (L-NNA, a nitric oxide synthase inhibitor, 100 μM were added sequentially for spontaneous and electrically-stimulated contractions. Tetrodotoxin was used to confirm any neuronal involvement.In spontaneous contraction, L-NNA increased basal tone and peak in both muscle layers, while amplitude and frequency were unaffected. EFS (up to 10 Hz uniformly induced initial contraction and subsequent relaxation in a frequency-dependent manner. Atropine abolished initial on-contraction and induced only relaxation during EFS. While MRS2500 showed no additional influence, L-NNA reversed relaxation (p = 0.012 in circular muscle, and p = 0.006 in longitudinal muscle. Tetrodotoxin abolished any EFS-induced motor response.The relaxation of human gastric fundus muscle is reduced by nitrergic inhibition. Hence, nitrergic pathway appears to be the main mechanism for the human gastric fundus relaxation.

  16. Relaxation of photoconductivity and persistent photoconductivity in TiO2 nanotubes

    International Nuclear Information System (INIS)

    Enachi, Mihail; Braniste, Tudor; Borodin, Eugeniu; Postolache, Vitalie

    2013-01-01

    Relaxation of photoconductivity is investigated in titania nanotubes produced by electrochemical treatment of Ti foils in organic electrolytes with subsequent thermal treatment at 400 degrees Celsius in air. The photoconductivity was excited both in air and in vacuum with the radiation from a xenon lamp passed through different filters to vary the excitation intensity and wavelength. It was found that the photoconductivity relaxation process consists of two components, i. e. a fast component a slow one. These two components behave differently in air and in the vacuum. The fast component is even faster under vacuum, while the slow component in vacuum is much slower, therefore leading to persistent photoconductivity. The possibility of removing the persistent photoconductivity state by exposure to air is investigated. (authors)

  17. Flexible Coupling of Respiration and Vocalizations with Locomotion and Head Movements in the Freely Behaving Rat

    Directory of Open Access Journals (Sweden)

    Joseph Andrews Alves

    2016-01-01

    Full Text Available Quadrupedal mammals typically synchronize their respiration with body movements during rhythmic locomotion. In the rat, fast respiration is coupled to head movements during sniffing behavior, but whether respiration is entrained by stride dynamics is not known. We recorded intranasal pressure, head acceleration, instantaneous speed, and ultrasonic vocalizations from male and female adult rats while freely behaving in a social environment. We used high-speed video recordings of stride to understand how head acceleration signals relate to locomotion and developed techniques to identify episodes of sniffing, walking, trotting, and galloping from the recorded variables. Quantitative analysis of synchrony between respiration and head acceleration rhythms revealed that respiration and locomotion movements were coordinated but with a weaker coupling than expected from previous work in other mammals. We have recently shown that rats behaving in social settings produce high rates of ultrasonic vocalizations during locomotion bouts. Accordingly, rats emitted vocalizations in over half of the respiratory cycles during fast displacements. We present evidence suggesting that emission of these calls disrupts the entrainment of respiration by stride. The coupling between these two variables is thus flexible, such that it can be overridden by other behavioral demands.

  18. The games economists play: Why economics students behave more selfishly than other students.

    Directory of Open Access Journals (Sweden)

    Philipp Gerlach

    Full Text Available Do economics students behave more selfishly than other students? Experiments involving monetary allocations suggest so. This article investigates the underlying motives for the economic students' more selfish behavior by separating three potential explanatory mechanisms: economics students are less concerned with fairness when making allocation decisions; have a different notion of what is fair in allocations; or are more skeptical about other people's allocations, which in turn makes them less willing to comply with a shared fairness norm. The three mechanisms were tested by inviting students from various disciplines to participate in a relatively novel experimental game and asking all participants to give reasons for their choices. Compared with students of other disciplines, economics students were about equally likely to mention fairness in their comments; had a similar notion of what was fair in the situation; however, they expected lower offers, made lower offers, and were less willing to enforce compliance with a fair allocation at a cost to themselves. The economics students' lower expectations mediated their allocation decisions, suggesting that economics students behaved more selfishly because they expected others not to comply with the shared fairness norm.

  19. An Improved Quantum-Behaved Particle Swarm Optimization Algorithm with Elitist Breeding for Unconstrained Optimization.

    Science.gov (United States)

    Yang, Zhen-Lun; Wu, Angus; Min, Hua-Qing

    2015-01-01

    An improved quantum-behaved particle swarm optimization with elitist breeding (EB-QPSO) for unconstrained optimization is presented and empirically studied in this paper. In EB-QPSO, the novel elitist breeding strategy acts on the elitists of the swarm to escape from the likely local optima and guide the swarm to perform more efficient search. During the iterative optimization process of EB-QPSO, when criteria met, the personal best of each particle and the global best of the swarm are used to generate new diverse individuals through the transposon operators. The new generated individuals with better fitness are selected to be the new personal best particles and global best particle to guide the swarm for further solution exploration. A comprehensive simulation study is conducted on a set of twelve benchmark functions. Compared with five state-of-the-art quantum-behaved particle swarm optimization algorithms, the proposed EB-QPSO performs more competitively in all of the benchmark functions in terms of better global search capability and faster convergence rate.

  20. A portable telemetry system for brain stimulation and neuronal activity recording in freely behaving small animals.

    Science.gov (United States)

    Ye, Xuesong; Wang, Peng; Liu, Jun; Zhang, Shaomin; Jiang, Jun; Wang, Qingbo; Chen, Weidong; Zheng, Xiaoxiang

    2008-09-30

    A portable multi-channel telemetry system which can be used for brain stimulation and neuronal activity recording in freely behaving small animals is described here. This system consists of three major components of headstage, backpack and portable Personal Digital Assistant (PDA). The headstage contains high precision instrument amplifiers with high input impedance. The backpack is comprised of two parts: (1) a main board (size: 36 mm x 22 mm x 3.5 mm and weight: 40 g with batteries, 20 g without), with current/voltage stimulator and special circuit suitable for neuronal activity recording and (2) and a bluetooth transceiver, with a high data transmission rate up to 70 kb/s, suitable for downloading stimulation commands and uploading acquired data. We recorded neuronal activities of the primary motor area of a freely behaving rat with 12-bit resolution at 12 k samples/s. The recorded data and analysis results showed that the system was successful by comparing with the commercial equipment Cerebus 128-Channel Data Acquisition System (Cyberkinetics Inc.). Using the PDA, we can control stimulation and recording. It provides a flexible method to do some research work in the circumstances where other approaches would be difficult or impossible.

  1. Acute effects of 15min static or contract-relax stretching modalities on plantar flexors neuromuscular properties.

    Science.gov (United States)

    Babault, Nicolas; Kouassi, Blah Y L; Desbrosses, Kevin

    2010-03-01

    The present study aimed to investigate the immediate effects of 15 min static or sub-maximal contract-relax stretching modalities on the neuromuscular properties of plantar flexor muscles. Ten male volunteers were tested before and immediately after 15 min static or contract-relax stretching programs of plantar flexor muscles (20 stretches). Static stretching consisted in 30s stretches to the point of discomfort. For the contract-relax stretching modality, subjects performed 6s sub-maximal isometric plantar flexion before 24s static stretches. Measurements included maximal voluntary isometric torque (MVT) and the corresponding electromyographic activity of soleus (SOL) and medial gastrocnemius (MG) muscles (RMS values), as well as maximal peak torque (Pt) elicited at rest by single supramaximal electrical stimulation of the tibial nerve. After 15 min stretching, significant MVT and SOL RMS decreases were obtained (-6.9+/-11.6% and -6.5+/-15.4%, respectively). No difference was obtained between stretching modalities. Pt remained unchanged after stretching. MG RMS changes were significantly different between stretching modalities (-9.4+/-18.3% and +3.5+/-11.6% after static and contract-relax stretching modalities, respectively). These findings indicated that performing 15 min static or contract-relax stretching had detrimental effects on the torque production capacity of plantar flexor muscles and should be precluded before competition. Mechanisms explaining this alteration seemed to be stretch modality dependent. Copyright 2009 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  2. Vibration sensitivity of human muscle spindles and Golgi tendon organs.

    Science.gov (United States)

    Fallon, James B; Macefield, Vaughan G

    2007-07-01

    The responses of the various muscle receptors to vibration are more complicated than a naïve categorization into stretch (muscle spindle primary ending), length (muscle spindle secondary endings), and tension (Golgi tendon organs) receptors. To emphasize the similarity of responses to small length changes, we recorded from 58 individual muscle afferents subserving receptors in the ankle or toe dorsiflexors of awake human subjects (32 primary endings, 20 secondary endings, and six Golgi tendon organs). Transverse sinusoidal vibration was applied to the distal tendon of the receptor-bearing muscle, while subjects either remained completely relaxed or maintained a weak isometric contraction of the appropriate muscle. In relaxed muscle, few units responded in a 1:1 manner to vibration, and there was no evidence of a preferred frequency of activation. In active muscle the response profiles of all three receptor types overlapped, with no significant difference in threshold between receptor types. These results emphasize that when intramuscular tension increases during a voluntary contraction, Golgi tendon organs and muscle spindle secondary endings, not just muscle spindle primary endings, can effectively encode small imposed length changes.

  3. The Effect of Relaxation Training on Symptoms of Anxiety and Depression in Patients with Breast Cancer

    Directory of Open Access Journals (Sweden)

    Meral Demiralp

    2011-04-01

    Full Text Available AIM: The purpose of this study was to investigate the effect of progressive muscle relaxation training on anxiety and depression in Turkish women with breast cancer undergoing adjuvant chemotherapy. METHOD: Data were collected between March 2005–2006. The sample of the study consisted of 27 newly diagnosed breast cancer patients who had planned to be cured with adjuvant chemotherapy. Patients who met these study criteria were accepted to the research programme and assigned to one of two groups, either progressive muscle relaxation (PMR group (n = 14 or control (n = 13 group sequentially. The effect of the progressive muscle relaxation training was measured at different stages of the treatment. A data collection form and Hospital Anxiety and Depression Scale were used to collect the data. In our research, for statistical analysis of data, parametric and nonparametric tests were used according to data range. Values of p0.05. CONCLUSION: Consequently, it was determined that relaxation exercises have no any significant effect on the symptoms of anxiety and depression alone. Based upon these results it was suggested that anxiety and depression symptoms must be assessed again by using different intervention modalities with different research designs and instruments. [TAF Prev Med Bull 2011; 10(2.000: 165-174

  4. STUDY TO COMPARE THE EFFECTIVENESS OF STATIC STRETCH AND HOLD RELAX TECHNIQUE OVER HAMSTRING FLEXIBILITY

    Directory of Open Access Journals (Sweden)

    Shanthi C

    2014-10-01

    Full Text Available Background: Numerous studies have documented on flexibility of muscles. Flexibility is defined as the ability of the muscles to lengthen allowing one joint or more than one joint in a series to move through a range of motion .Flexibility allows tissue to accommodate more easily to stress thus minimizing or preventing muscle injury. But this study sought to identify the study to compare the effectiveness of Static stretch and Hold relax technique over the hamstring flexibility. Methods: 30 healthy male adults with Hamstring tightness aged 21 to 35 years selected from general population through simple randomized technique. Samples are divided into two groups, static stretch Group-I(no.15 and Group-II Hold relax (no.=15.The outcome was measured with help of sit & reach test to see the Hamstring flexibility. Results: Comparison of the post test values of the group I and group II shows a significant difference between the outcomes of two groups with a “t” calculated value of 0.738 (unpaired “t” test. Conclusion: Both static stretch and hold relax Technique can cause very highly significant result in Hamstring Flexibility, further comparison shows very high significant difference between two groups and concludes that hold relax is better than static stretch in Hamstring Flexibility.

  5. Compaction and relaxation of biofilms

    KAUST Repository

    Valladares Linares, R.

    2015-06-18

    Operation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies. The objective of this study was to determine the occurrence, extent and timescale of biofilm compaction and relaxation (decompaction), caused by permeate flux variations. The impact of permeate flux changes on biofilm thickness, structure and stiffness was investigated in situ and non-destructively with optical coherence tomography using membrane fouling monitors operated at a constant crossflow velocity of 0.1 m s−1 with permeate production. The permeate flux was varied sequentially from 20 to 60 and back to 20 L m−2 h−1. The study showed that the average biofilm thickness on the membrane decreased after elevating the permeate flux from 20 to 60 L m−2 h−1 while the biofilm thickness increased again after restoring the original flux of 20 L m−2 h−1, indicating the occurrence of biofilm compaction and relaxation. Within a few seconds after the flux change, the biofilm thickness was changed and stabilized, biofilm compaction occurred faster than the relaxation after restoring the original permeate flux. The initial biofilm parameters were not fully reinstated: the biofilm thickness was reduced by 21%, biofilm stiffness had increased and the hydraulic biofilm resistance was elevated by 16%. Biofilm thickness was related to the hydraulic biofilm resistance. Membrane performance losses are related to the biofilm thickness, density and morphology, which are influenced by (variations in) hydraulic conditions. A (temporarily) permeate flux increase caused biofilm compaction, together with membrane performance losses. The impact of biofilms on membrane performance can be influenced (increased and reduced) by operational parameters. The article shows that a (temporary) pressure increase leads to more

  6. Longitudinal muscle of the esophagus: its role in esophageal health and disease.

    Science.gov (United States)

    Mittal, Ravinder K

    2013-07-01

    The muscularis propria of the esophagus is organized into circular and longitudinal muscle layers. The function of the longitudinal muscle and its role in bolus propulsion are not clear. The goal of this review is to summarize what is known of the role of the longitudinal muscle in health, as well as in sensory and motor disorders of the esophagus. Simultaneous manometry and ultrasound imaging reveal that, during peristalsis, the two muscle layers of the esophagus contract in perfect synchrony. On the contrary, during transient lower esophageal sphincter (LES) relaxation, longitudinal muscle contracts independent of the circular muscle. Recent studies have provided novel insights into the role of the longitudinal muscle in LES relaxation and descending relaxation of the esophagus. In certain diseases (e.g. some motility disorders of the esophagus), there is discoordination between the two muscle layers, which likely plays an important role in the genesis of dysphagia and delayed esophageal emptying. There is close temporal correlation between prolonged contractions of the longitudinal muscles of the esophagus and esophageal 'angina-like' pain. Novel techniques to record longitudinal muscle contraction are reviewed. Longitudinal muscles of the esophagus play a key role in the physiology and pathophysiology of esophageal sensory and motor function. Neuro-pharmacologic controls of circular and longitudinal muscle are different, which provides an opportunity for the development of novel pharmacological therapies in the treatment of esophageal sensory and motor disorders.

  7. Education based thinking and behaving? Towards an identity perspective for studying education differentials in public opinion and political participation

    NARCIS (Netherlands)

    Spruyt, Bram; Kuppens, Toon

    2015-01-01

    Education based thinking and behaving? Towards and identity perspective for studying education differentials in public opinion and political participation Abstract Ever since scholars started studying public opinion and political behaviour, they have reported substantial educational differences.

  8. Ultrasonic relaxations in borate glasses

    International Nuclear Information System (INIS)

    D'Angelo, G.; Tripodo, G.; Carini, G.; Cosio, E.; Bartolotta, A.; Di Marco, G.

    2004-01-01

    The attenuation and velocity of ultrasonic waves of frequencies in the range from 10 to 70 MHz have been measured in M 2 O-B 2 O 3 borate glasses (M: Li or Ag) as a function of temperature between 15 and 350 K. The velocity of sound waves decreases with increasing temperature in all the glasses, the decrease as the temperature is increased is larger in glasses containing silver than in those with lithium. A broad relaxation peak characterises the attenuation behaviour of the lithium and silver borate glasses at temperatures below 100 K and is paralleled by a corresponding dispersive behaviour of the sound velocity. Above 100 K, the ultrasonic velocity shows a nearly linear behaviour regulated by the vibrational anharmonicity, which decreases with increasing content of modifier oxide and is smaller in lithium than in silver borates. These results suggest that the relaxation of structural defects and the anharmonicity of borate glasses are strongly affected by two parameters: the number of bridging bonds per network forming ion and the polarising power of network modifier ions which occupy sites in the existing interstices

  9. Statistical mechanics of violent relaxation

    International Nuclear Information System (INIS)

    Shu, F.H.

    1978-01-01

    We reexamine the foundations of Lynden-Bell's statistical mechanical discussion of violent relaxation in collisionless stellar systems. We argue that Lynden-Bell's formulation in terms of a continuum description introduces unnecessary complications, and we consider a more conventional formulation in terms of particles. We then find the exclusion principle discovered by Lynden-Bell to be quantitatively important only at phase densities where two-body encounters are no longer negligible. Since the edynamical basis for the exclusion principle vanishes in such cases anyway, Lynden-Bell statistics always reduces in practice to Maxwell-Boltzmann statistics when applied to stellar systems. Lynden-Bell also found the equilibrium distribution function generally to be a sum of Maxwellians with velocity dispersions dependent on the phase density at star formation. We show that this difficulty vanishes in the particulate description for an encounterless stellar system as long as stars of different masses are initially well mixed in phase space. Our methods also demonstrate the equivalence between Gibbs's formalism which uses the microcanonical ensemble and Boltzmann's formalism which uses a coarse-grained continuum description. In addition, we clarify the concept of irreversible behavior on a macroscopic scale for an encounterless stellar system. Finally, we comment on the use of unusual macroscopic constraints to simulate the effects of incomplete relaxation

  10. Tbx15 controls skeletal muscle fibre-type determination and muscle metabolism

    Science.gov (United States)

    Lee, Kevin Y.; Singh, Manvendra K.; Ussar, Siegfried; Wetzel, Petra; Hirshman, Michael F.; Goodyear, Laurie J.; Kispert, Andreas; Kahn, C. Ronald

    2015-01-01

    Skeletal muscle is composed of both slow-twitch oxidative myofibers and fast-twitch glycolytic myofibers that differentially impact muscle metabolism, function and eventually whole-body physiology. Here we show that the mesodermal transcription factor T-box 15 (Tbx15) is highly and specifically expressed in glycolytic myofibers. Ablation of Tbx15 in vivo leads to a decrease in muscle size due to a decrease in the number of glycolytic fibres, associated with a small increase in the number of oxidative fibres. This shift in fibre composition results in muscles with slower myofiber contraction and relaxation, and also decreases whole-body oxygen consumption, reduces spontaneous activity, increases adiposity and glucose intolerance. Mechanistically, ablation of Tbx15 leads to activation of AMPK signalling and a decrease in Igf2 expression. Thus, Tbx15 is one of a limited number of transcription factors to be identified with a critical role in regulating glycolytic fibre identity and muscle metabolism. PMID:26299309

  11. The Regulation of Skeletal Muscle Active Hyperemia: The Differential Role of Adenosine in Muscles of Varied Fiber Types

    Science.gov (United States)

    1986-04-21

    cyclase mediates the coronary relaxation induced by adenosine. Adenosine-induced relaxation is accompanied by cyclic AMP accumulation in bovine ...and the reaction was started by adding 0.01 ml L-glutamic dehydrogenase ( bovine liver; 1200 U•ml-1 in SO% glycerol and vhosphate buffer; p~ 7.4...Physiol: London 68: 213-237, 1929. Dudley, G.A. and R.L. Terjung. Influence of acidosis on AMP deaTIIinase activity in contracting fast-twitch muscle

  12. Relaxation of the chemical bond skin chemisorption size matter ZTP mechanics H2O myths

    CERN Document Server

    Sun, Chang Q

    2014-01-01

    The aim of this book is to explore the detectable properties of a material to the parameters of bond and non-bond involved and to clarify the interdependence of various properties. This book is composed of four parts; Part I deals with the formation and relaxation dynamics of bond and non-bond during chemisorptions with uncovering of the correlation among the chemical bond, energy band, and surface potential barrier (3B) during reactions; Part II is focused on the relaxation of bonds between atoms with fewer neighbors than the ideal in bulk with unraveling of the bond order-length-strength (BOLS) correlation mechanism, which clarifies the nature difference between nanostructures and bulk of the same substance; Part III deals with the relaxation dynamics of bond under heating and compressing with revealing of rules on the temperature-resolved elastic and plastic properties of low-dimensional materials; Part IV is focused on the asymmetric relaxation dynamics of the hydrogen bond (O:H-O) and the anomalous behav...

  13. Paramagnetic relaxation effects in perturbed angular correlations for arbitrary electronic relaxation time

    International Nuclear Information System (INIS)

    Chopin, C.; Spanjaard, D.; Hartmann-Boutron, F.

    1975-01-01

    Previous perturbation treatments of paramagnetic relaxation effects in γγ PAC were limited to the case of very short electronic relaxation times. This limitation is circumvented by invoking a new perturbation theory recently elaborated by Hirst and others for handling relaxation effects in Moessbauer spectra. Under the assumption of spherical electronic relaxation the perturbation factors are computed as functions of certain relaxation parameters which are directly related to the microscopic relaxation Hamiltonian. The results are compared to those of the stochastic theory of Scherer and Blume [fr

  14. Optimasi Penempatan Menara BTS Menggunakan Quantum-Behaved Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Mohamad Fatkhur Rohman

    2016-11-01

    Full Text Available Universal Mobile Telecomunication System (UMTS saat ini dipandang sebagai sebuah sistem impian yang menggantikan Global System for Mobile Communication (GSM dan merupakan salah satu evolusi generasi ketiga (3G dari jaringan mobile. Salah satu komponen pendukung jaringan UMTS adalah Node B, Node B dapat dianalogikan sebagai BTS. Seiring perkembangan kebutuhan pelanggan yang semakin meningkat, kebutuhan akan BTS(Node B semakin bertambah, hal ini menyebabkan banyaknya jumlah menara BTS da menyebabkan pemandangan yang kurang bagus bagi visualisasi kota.oleh karena itu perlu dilakukan optimisasi penempatan menara BTS. Salah satu metode untuk mengoptimasi adalah Quantum-behaved Particle Swarm Optimization. Maka dalam penelitian ini akan dirancang simulasi optimasi penempatan BTS menggunakan QPSO dengan parameter yang akan dioptimasi adalah Coverage Area dan Trafik. Dari hasil penelitian yang dilakukan, Algoritma QPSO mampu mengurangi jumlah BTS dari 55 BTS menjadi 43 BTS.

  15. Why consumers behave as they do with respect to food safety and risk information

    DEFF Research Database (Denmark)

    Verbeke, Wim; Frewer, Lynn J.; Scholderer, Joachim

    2007-01-01

    rankings. The aim of this contribution is to provide a better understanding to food risk analysts of why consumers behave as they do with respect to food safety and risk information. This paper presents some cases of seemingly irrational and inconsistent consumer behaviour with respect to food safety...... and risk information and provides explanations for these behaviours based on the nature of the risk and individual psychological processes. Potential solutions for rebuilding consumer confidence in food safety and bridging between lay and expert opinions towards food risks are reviewed. These include......In recent years, it seems that consumers are generally uncertain about the safety and quality of their food and their risk perception differs substantially from that of experts. Hormone and veterinary drug residues in meat persist to occupy a high position in European consumers' food concern...

  16. Draft Tube Baffle (DTB) crystallizers: A study of stationary and dynamically behaving Crystal Size Distributions (CSD)

    Science.gov (United States)

    Deleer, B. G. M.

    1981-11-01

    Based on population balance, CSD behavior as a function of geometrical and operating variables was studied, using a crystallizer. A potash alum-water system, involving a separation technique which uses surface active agents and an apolar, organic liquid to separate potash alum crystals from mother liquid under the influence of gravity was used to check experimental findings against literature data. Results show action of annular settling spaces is strongly influenced by fluid velocities perpendicular to those directed upwards. The well-mixed volume decreases with increasing crystallizer size until a minimum effective volume is reached. As supersaturation is constant throughout the crystallizer volume under stationary operating conditions, the annular settling space behaves like a growth chamber for crystals in its volume. Swirl in the lower part of the annular volume introduces significant back mixing. Crystals within this space either grow and return to the well-mixed part, or withdraw from the annular volume permanently.

  17. A Swarm Optimization Genetic Algorithm Based on Quantum-Behaved Particle Swarm Optimization.

    Science.gov (United States)

    Sun, Tao; Xu, Ming-Hai

    2017-01-01

    Quantum-behaved particle swarm optimization (QPSO) algorithm is a variant of the traditional particle swarm optimization (PSO). The QPSO that was originally developed for continuous search spaces outperforms the traditional PSO in search ability. This paper analyzes the main factors that impact the search ability of QPSO and converts the particle movement formula to the mutation condition by introducing the rejection region, thus proposing a new binary algorithm, named swarm optimization genetic algorithm (SOGA), because it is more like genetic algorithm (GA) than PSO in form. SOGA has crossover and mutation operator as GA but does not need to set the crossover and mutation probability, so it has fewer parameters to control. The proposed algorithm was tested with several nonlinear high-dimension functions in the binary search space, and the results were compared with those from BPSO, BQPSO, and GA. The experimental results show that SOGA is distinctly superior to the other three algorithms in terms of solution accuracy and convergence.

  18. Parameters estimation online for Lorenz system by a novel quantum-behaved particle swarm optimization

    International Nuclear Information System (INIS)

    Gao Fei; Tong Hengqing; Li Zhuoqiu

    2008-01-01

    This paper proposes a novel quantum-behaved particle swarm optimization (NQPSO) for the estimation of chaos' unknown parameters by transforming them into nonlinear functions' optimization. By means of the techniques in the following three aspects: contracting the searching space self-adaptively; boundaries restriction strategy; substituting the particles' convex combination for their centre of mass, this paper achieves a quite effective search mechanism with fine equilibrium between exploitation and exploration. Details of applying the proposed method and other methods into Lorenz systems are given, and experiments done show that NQPSO has better adaptability, dependability and robustness. It is a successful approach in unknown parameter estimation online especially in the cases with white noises

  19. An Image Enhancement Method Using the Quantum-Behaved Particle Swarm Optimization with an Adaptive Strategy

    Directory of Open Access Journals (Sweden)

    Xiaoping Su

    2013-01-01

    Full Text Available Image enhancement techniques are very important to image processing, which are used to improve image quality or extract the fine details in degraded images. In this paper, two novel objective functions based on the normalized incomplete Beta transform function are proposed to evaluate the effectiveness of grayscale image enhancement and color image enhancement, respectively. Using these objective functions, the parameters of transform functions are estimated by the quantum-behaved particle swarm optimization (QPSO. We also propose an improved QPSO with an adaptive parameter control strategy. The QPSO and the AQPSO algorithms, along with genetic algorithm (GA and particle swarm optimization (PSO, are tested on several benchmark grayscale and color images. The results show that the QPSO and AQPSO perform better than GA and PSO for the enhancement of these images, and the AQPSO has some advantages over QPSO due to its adaptive parameter control strategy.

  20. Cross relaxation in nitroxide spin labels

    DEFF Research Database (Denmark)

    Marsh, Derek

    2016-01-01

    Cross relaxation, and mI-dependence of the intrinsic electron spin-lattice relaxation rate We, are incorporated explicitly into the rate equations for the electron-spin population differences that govern the saturation behaviour of 14N- and 15N-nitroxide spin labels. Both prove important in spin......-label EPR and ELDOR, particularly for saturation recovery studies. Neither for saturation recovery, nor for CW-saturation EPR and CW-ELDOR, can cross relaxation be described simply by increasing the value of We, the intrinsic spin-lattice relaxation rate. Independence of the saturation recovery rates from...... the hyperfine line pumped or observed follows directly from solution of the rate equations including cross relaxation, even when the intrinsic spin-lattice relaxation rate We is mI-dependent....

  1. Rodent scope: a user-configurable digital wireless telemetry system for freely behaving animals.

    Directory of Open Access Journals (Sweden)

    David Ball

    Full Text Available This paper describes the design and implementation of a wireless neural telemetry system that enables new experimental paradigms, such as neural recordings during rodent navigation in large outdoor environments. RoSco, short for Rodent Scope, is a small lightweight user-configurable module suitable for digital wireless recording from freely behaving small animals. Due to the digital transmission technology, RoSco has advantages over most other wireless modules of noise immunity and online user-configurable settings. RoSco digitally transmits entire neural waveforms for 14 of 16 channels at 20 kHz with 8-bit encoding which are streamed to the PC as standard USB audio packets. Up to 31 RoSco wireless modules can coexist in the same environment on non-overlapping independent channels. The design has spatial diversity reception via two antennas, which makes wireless communication resilient to fading and obstacles. In comparison with most existing wireless systems, this system has online user-selectable independent gain control of each channel in 8 factors from 500 to 32,000 times, two selectable ground references from a subset of channels, selectable channel grounding to disable noisy electrodes, and selectable bandwidth suitable for action potentials (300 Hz-3 kHz and low frequency field potentials (4 Hz-3 kHz. Indoor and outdoor recordings taken from freely behaving rodents are shown to be comparable to a commercial wired system in sorting for neural populations. The module has low input referred noise, battery life of 1.5 hours and transmission losses of 0.1% up to a range of 10 m.

  2. Structural relaxation in annealed hyperquenched basaltic glasses

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, John C.; Potuzak, M.

    2012-01-01

    The enthalpy relaxation behavior of hyperquenched (HQ) and annealed hyperquenched (AHQ) basaltic glass is investigated through calorimetric measurements. The results reveal a common onset temperature of the glass transition for all the HQ and AHQ glasses under study, indicating that the primary...... relaxation is activated at the same temperature regardless of the initial departure from equilibrium. The analysis of secondary relaxation at different annealing temperatures provides insights into the enthalpy recovery of HQ glasses....

  3. The effect of pneumatic tourniquets on skeletal muscle physiology.

    Science.gov (United States)

    Patterson, S; Klenerman, L; Biswas, M; Rhodes, A

    1981-01-01

    The effect of 3- and 5-hour pneumatic tourniquets on skeletal muscle physiology was investigated. Maximum isometric tension development, contraction and half relaxation times were measured in the muscles lying immediately under and distal to the tourniquet. On release of the tourniquet no consistent difference between control and experimental muscles was observed with respect to contraction and half relaxation times; however, there was a marked reduction in maximum isometric tension development. On the sixth day after release of a 5-hour tourniquet, isometric tension was reduced to 2--20 per cent of the control value in the distal muscle and to 40--60 per cent of the control value in the compressed muscle. Six days after a 3-hour tourniquet the compressed muscle tension was reduced to approximately 80 per cent of the control value whilst in the distal muscle, tension development varied from normal to 64 per cent of the control value. Thus it is shown that the effect on muscle contraction after a 3-hour tourniquet is not immediately reversed by the restoration of the blood supply. A reduction in muscle strength follows which may take a week or more to recover.

  4. Dielectric Relaxation of Water: Theory and Experiment

    International Nuclear Information System (INIS)

    Adhikari, Narayan Prasad; Paudyal, Harihar; Johri, Manoj

    2010-06-01

    We have studied the hydrogen bond dynamics and methods for evaluation of probability and relaxation time for hydrogen bond network. Further, dielectric relaxation time has been calculated by using a diagonalization procedure by obtaining eigen values (inverse of relaxation time) of a master equation framed on the basis of Fokker-Planck equations. Microwave cavity spectrometer has been described to make measurements of relaxation time. Slater's perturbation equations are given for the analysis of the data. A comparison of theoretical and experimental data shows that there is a need for improvements in the theoretical model and experimental techniques to provide exact information about structural properties of water. (author)

  5. Cooling-history effects on magnetic relaxation through quantum tunneling

    Science.gov (United States)

    Fernandez, Julio; Alonso, Juan

    2003-03-01

    Magnetic clusters, such as Fe8 and Mn_12, that make up the core of large organometallic molecules, behave at low temperatures as large single spins S. In crystals, magnetic anisotropy energies U inhibit magnetic relaxation of these spins, which can then proceed at very small temperatures (at k_BT tunneling (MQT). Magnetic dipolar interactions then play an essential role. We study how an Ising system of spins that interact through magnetic dipolar fields relaxes. A spin is allowed to flip, at rate Γ, only if the magnetic field h acting on it is within some tunnel window -hw < h< h_w. We let (1) this system be initially held for some time at some temperature Ta that is above both the long-range ordering temperature and T ˜ U/S, and (2) apply a magnetic field at t=0, inmediately after the system is quenched to T < 0.1U/S. This is somewhat as in the experiments of Wernsdorfer et al on Fe_8. The time evolution of the magnetiztion m and field distributions after the field is applied at t=0 is studied. For small applied fields H, m ˜= hw HF(Γ t). In addition, F(Γ t)˜= cΓ t for Γ t < 1 and F(Γ t)˜= cΓ t for 1 <Γ t < (h_d/h_w)^2, where hd is a nearest neighbor dipolar field. We will show how c depends on the cooling protocol. Finally, m saturates at m_s˜= 0.13\\varepsilon_aH.

  6. Pair plasma relaxation time scales.

    Science.gov (United States)

    Aksenov, A G; Ruffini, R; Vereshchagin, G V

    2010-04-01

    By numerically solving the relativistic Boltzmann equations, we compute the time scale for relaxation to thermal equilibrium for an optically thick electron-positron plasma with baryon loading. We focus on the time scales of electromagnetic interactions. The collisional integrals are obtained directly from the corresponding QED matrix elements. Thermalization time scales are computed for a wide range of values of both the total-energy density (over 10 orders of magnitude) and of the baryonic loading parameter (over 6 orders of magnitude). This also allows us to study such interesting limiting cases as the almost purely electron-positron plasma or electron-proton plasma as well as intermediate cases. These results appear to be important both for laboratory experiments aimed at generating optically thick pair plasmas as well as for astrophysical models in which electron-positron pair plasmas play a relevant role.

  7. Relaxing Chosen-Ciphertext Security

    DEFF Research Database (Denmark)

    Canetti, Ran; Krawczyk, Hugo; Nielsen, Jesper Buus

    2003-01-01

    Security against adaptive chosen ciphertext attacks (or, CCA security) has been accepted as the standard requirement from encryption schemes that need to withstand active attacks. In particular, it is regarded as the appropriate security notion for encryption schemes used as components within...... general protocols and applications. Indeed, CCA security was shown to suffice in a large variety of contexts. However, CCA security often appears to be somewhat too strong: there exist encryption schemes (some of which come up naturally in practice) that are not CCA secure, but seem sufficiently secure...... “for most practical purposes.” We propose a relaxed variant of CCA security, called Replayable CCA (RCCA) security. RCCA security accepts as secure the non-CCA (yet arguably secure) schemes mentioned above; furthermore, it suffices for most existing applications of CCA security. We provide three...

  8. Nicotine impairs cyclooxygenase-2-dependent kinin-receptor-mediated murine airway relaxations

    International Nuclear Information System (INIS)

    Xu, Yuan; Cardell, Lars-Olaf

    2014-01-01

    . - Highlights: • Nicotine from smoking impaired epithelial COX-2-mediated airway relaxation. • Nicotine's effects were at least partially mediated by α7-nicotinic receptors. • Kinin-receptor-mediated airway relaxations are mediated by EP2 receptors in mice. • Nicotine reduced mPGES-1 mRNA and protein expressions in airway smooth muscle. • Dexamethasone could not restore nicotine-impaired airway relaxations

  9. Nicotine impairs cyclooxygenase-2-dependent kinin-receptor-mediated murine airway relaxations

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yuan, E-mail: yuan.xu@ki.se; Cardell, Lars-Olaf

    2014-02-15

    some patients with asthma. - Highlights: • Nicotine from smoking impaired epithelial COX-2-mediated airway relaxation. • Nicotine's effects were at least partially mediated by α7-nicotinic receptors. • Kinin-receptor-mediated airway relaxations are mediated by EP2 receptors in mice. • Nicotine reduced mPGES-1 mRNA and protein expressions in airway smooth muscle. • Dexamethasone could not restore nicotine-impaired airway relaxations.

  10. Physiological studies of muscle rigor mortis in the fowl

    International Nuclear Information System (INIS)

    Nakahira, S.; Kaneko, K.; Tanaka, K.

    1990-01-01

    A simple system was developed for continuous measurement of muscle contraction during nor mortis. Longitudinal muscle strips dissected from the Peroneus Longus were suspended in a plastic tube containing liquid paraffin. Mechanical activity was transmitted to a strain-gauge transducer which is connected to a potentiometric pen-recorder. At the onset of measurement 1.2g was loaded on the muscle strip. This model was used to study the muscle response to various treatments during nor mortis. All measurements were carried out under the anaerobic condition at 17°C, except otherwise stated. 1. The present system was found to be quite useful for continuous measurement of muscle rigor course. 2. Muscle contraction under the anaerobic condition at 17°C reached a peak about 2 hours after the onset of measurement and thereafter it relaxed at a slow rate. In contrast, the aerobic condition under a high humidity resulted in a strong rigor, about three times stronger than that in the anaerobic condition. 3. Ultrasonic treatment (37, 000-47, 000Hz) at 25°C for 10 minutes resulted in a moderate muscle rigor. 4. Treatment of muscle strip with 2mM EGTA at 30°C for 30 minutes led to a relaxation of the muscle. 5. The muscle from the birds killed during anesthesia with pentobarbital sodium resulted in a slow rate of rigor, whereas the birds killed one day after hypophysectomy led to a quick muscle rigor as seen in intact controls. 6. A slight muscle rigor was observed when muscle strip was placed in a refrigerator at 0°C for 18.5 hours and thereafter temperature was kept at 17°C. (author)

  11. Evaluating Swallowing Muscles Essential for Hyolaryngeal Elevation by Using Muscle Functional Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Pearson, William G.; Hindson, David F.; Langmore, Susan E.; Zumwalt, Ann C.

    2013-01-01

    Purpose: Reduced hyolaryngeal elevation, a critical event in swallowing, is associated with radiation therapy. Two muscle groups that suspend the hyoid, larynx, and pharynx have been proposed to elevate the hyolaryngeal complex: the suprahyoid and longitudinal pharyngeal muscles. Thought to assist both groups is the thyrohyoid, a muscle intrinsic to the hyolaryngeal complex. Intensity modulated radiation therapy guidelines designed to preserve structures important to swallowing currently exclude the suprahyoid and thyrohyoid muscles. This study used muscle functional magnetic resonance imaging (mfMRI) in normal healthy adults to determine whether both muscle groups are active in swallowing and to test therapeutic exercises thought to be specific to hyolaryngeal elevation. Methods and Materials: mfMRI data were acquired from 11 healthy subjects before and after normal swallowing and after swallowing exercise regimens (the Mendelsohn maneuver and effortful pitch glide). Whole-muscle transverse relaxation time (T2 signal, measured in milliseconds) profiles of 7 test muscles were used to evaluate the physiologic response of each muscle to each condition. Changes in effect size (using the Cohen d measure) of whole-muscle T2 profiles were used to determine which muscles underlie swallowing and swallowing exercises. Results: Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity during swallowing) for the T2 signal profile of the thyrohyoid was a d value of 0.09; a d value of 0.40 for the mylohyoid, 0.80 for the geniohyoid, 0.04 for the anterior digastric, and 0.25 for the posterior digastric-stylohyoid in the suprahyoid muscle group; and d values of 0.47 for the palatopharyngeus and 0.28 for the stylopharyngeus muscles in the longitudinal pharyngeal muscle group. The Mendelsohn maneuver and effortful pitch glide swallowing exercises showed significant effect size changes for all muscles tested, except for the thyrohyoid. Conclusions

  12. Evaluating Swallowing Muscles Essential for Hyolaryngeal Elevation by Using Muscle Functional Magnetic Resonance Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, William G., E-mail: bp1@bu.edu [Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts (United States); Hindson, David F. [Department of Radiology, Boston Medical Center, Boston, Massachusetts (United States); Langmore, Susan E. [Department of Otolaryngology, Boston Medical Center, Boston, Massachusetts (United States); Speech and Hearing Sciences, Boston University, Boston, Massachusetts (United States); Zumwalt, Ann C. [Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts (United States)

    2013-03-01

    Purpose: Reduced hyolaryngeal elevation, a critical event in swallowing, is associated with radiation therapy. Two muscle groups that suspend the hyoid, larynx, and pharynx have been proposed to elevate the hyolaryngeal complex: the suprahyoid and longitudinal pharyngeal muscles. Thought to assist both groups is the thyrohyoid, a muscle intrinsic to the hyolaryngeal complex. Intensity modulated radiation therapy guidelines designed to preserve structures important to swallowing currently exclude the suprahyoid and thyrohyoid muscles. This study used muscle functional magnetic resonance imaging (mfMRI) in normal healthy adults to determine whether both muscle groups are active in swallowing and to test therapeutic exercises thought to be specific to hyolaryngeal elevation. Methods and Materials: mfMRI data were acquired from 11 healthy subjects before and after normal swallowing and after swallowing exercise regimens (the Mendelsohn maneuver and effortful pitch glide). Whole-muscle transverse relaxation time (T2 signal, measured in milliseconds) profiles of 7 test muscles were used to evaluate the physiologic response of each muscle to each condition. Changes in effect size (using the Cohen d measure) of whole-muscle T2 profiles were used to determine which muscles underlie swallowing and swallowing exercises. Results: Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity during swallowing) for the T2 signal profile of the thyrohyoid was a d value of 0.09; a d value of 0.40 for the mylohyoid, 0.80 for the geniohyoid, 0.04 for the anterior digastric, and 0.25 for the posterior digastric-stylohyoid in the suprahyoid muscle group; and d values of 0.47 for the palatopharyngeus and 0.28 for the stylopharyngeus muscles in the longitudinal pharyngeal muscle group. The Mendelsohn maneuver and effortful pitch glide swallowing exercises showed significant effect size changes for all muscles tested, except for the thyrohyoid. Conclusions

  13. Levcromakalim- and isoprenaline-induced relaxation of human isolated airways--role of the epithelium and of K+ channel activation.

    Science.gov (United States)

    Black, J L; Johnson, P R; McKay, K O; Carey, D; Armour, C L

    1994-06-01

    In this study we have investigated the mechanism of action of levcromakalim and isoprenaline in human isolated airways with respect to the K+ channels they activate and the possibility that these smooth muscle relaxants activate K+ channels on the airway epithelium. Mechanical removal of the epithelial layer (mean percentage of epithelium present 20 +/- 3%, n = 20 tissues) did not affect the relaxation responses to levcromakalim or isoprenaline, either in terms of maximal relaxation or sensitivity. Whilst having no effect on isoprenaline-induced relaxation, studied from basal tone, the ATP-sensitive K+ channel blocker BRL 31660 (10, 30 and 50 microM) reduced relaxation responses induced (from basal tone) by levcromakalim from 74 +/- 6% (of the maximal response to isoprenaline) to 48 +/- 12% (n = 7), 9 +/- 9% (n = 4) and 0 (n = 4), respectively. Charybdotoxin, a blocker of high conductance Ca(2+)-activated K+ channels, at concentrations of 30 and 100 nM, had no effect on either levcromakalim- or or isoprenaline-induced relaxation responses and yet charybdotoxin was active at KCa channels in outside-out patches of hippocampal granule cells. Moreover, tetraethylammonium (10 mM) inhibited neither isoprenaline- nor levcromakalim-induced relaxation. This study has demonstrated that the relaxation responses elicited in human bronchus to isoprenaline and levcromakalim are likely to be the result of direct effects on the smooth muscle with no contribution from epithelial receptors or K+ channels. The actions of levcromakalim appear to be mediated only via activation of KATP channels. Further, we have made the important observation that, under the experimental conditions of our study, isoprenaline does not activate the KCa channel to produce relaxation in human bronchus.

  14. The Effects of Progressive Relaxation and Music on Attention, Relaxation, and Stress Responses: An Investigation of the Cognitive-Behavioral Model of Relaxation

    National Research Council Canada - National Science Library

    Scheufele, Peter

    1999-01-01

    ...) suggested that stress management techniques have specific effects A compromise position suggests that the specific effects of relaxation techniques are superimposed upon a general relaxation response...

  15. Relaxation property of the fractional Brownian particle

    International Nuclear Information System (INIS)

    Wang Litan; Lung, C.W.

    1988-08-01

    Dynamic susceptibility of a diffusion system associated with the fractional Brownian motion (fBm) was examined for the fractal property of the Non-Debye relaxation process. The comparisons between fBm and other approaches were made. Anomalous diffusion and the Non-Debye relaxation processes were discussed with this approach. (author). 8 refs, 1 fig

  16. Lifshitz quasinormal modes and relaxation from holography

    NARCIS (Netherlands)

    Sybesma, Watse|info:eu-repo/dai/nl/369283074; Vandoren, Stefan|info:eu-repo/dai/nl/304830739

    2015-01-01

    We obtain relaxation times for field theories with Lifshitz scaling and with holographic duals Einstein-Maxwell-Dilaton gravity theories. This is done by computing quasinormal modes of a bulk scalar field in the presence of Lifshitz black branes. We determine the relation between relaxation time and

  17. Superparamagnetic relaxation of weakly interacting particles

    DEFF Research Database (Denmark)

    Mørup, Steen; Tronc, Elisabeth

    1994-01-01

    The influence of particle interactions on the superparamagnetic relaxation time has been studied by Mossbauer spectroscopy in samples of maghemite (gamma-Fe2O3) particles with different particle sizes and particle separations. It is found that the relaxation time decreases with decreasing particl...

  18. Models of Flux Tubes from Constrained Relaxation

    Indian Academy of Sciences (India)

    tribpo

    J. Astrophys. Astr. (2000) 21, 299 302. Models of Flux Tubes from Constrained Relaxation. Α. Mangalam* & V. Krishan†, Indian Institute of Astrophysics, Koramangala,. Bangalore 560 034, India. *e mail: mangalam @ iiap. ernet. in. † e mail: vinod@iiap.ernet.in. Abstract. We study the relaxation of a compressible plasma to ...

  19. Superparamagnetic relaxation in alpha-Fe particles

    DEFF Research Database (Denmark)

    Bødker, Franz; Mørup, Steen; Pedersen, Michael Stanley

    1998-01-01

    The superparamagnetic relaxation time of carbon-supported alpha-Fe particles with an average size of 3.0 Mm has been studied over a large temperature range by the use of Mossbauer spectroscopy combined with AC and DC magnetization measurements. It is found that the relaxation time varies...

  20. Baryogenesis via Elementary Goldstone Higgs Relaxation

    DEFF Research Database (Denmark)

    Gertov, Helene; Pearce, Lauren; Sannino, Francesco

    2016-01-01

    We extend the relaxation mechanism to the Elementary Goldstone Higgs framework. Besides studying the allowed parameter space of the theory we add the minimal ingredients needed for the framework to be phenomenologically viable. The very nature of the extended Higgs sector allows to consider very ...... but radiatively generated, it is possible to generate the observed matter-antimatter asymmetry via the relaxation mechanism....

  1. [Transient lower esophageal sphincter relaxation and the related esophageal motor activities].

    Science.gov (United States)

    Han, Seung Hyo; Hong, Su Jin

    2012-03-01

    Transient lower esophageal sphincter (LES) relaxation (TLESR) is defined as LES relaxation without a swallow. TLESRs are observed in both of the normal individuals and the patients with gastroesophageal reflux disorder (GERD). However, TLESR is widely considered as the major mechanism of the GERD. The new equipments such as high resolution manometry and impedance pH study is helped to understand of TLESR and the related esophageal motor activities. The strong longitudinal muscle contraction was observed during development of TLESR. Most of TLESRs are terminated by TLESR related motor events such as primary peristalsis and secondary contractions. The majority of TLESRs are associated with gastroesophageal reflux. Upper esophageal sphincter (UES) contraction is mainly associated with liquid reflux during recumbent position and UES relaxation predominantly related with air reflux during upright position. The frequency of TLESR in GERD patients seems to be not different compared to normal individuals, but the refluxate of GERD patients tend to be more acidic during TLESR.

  2. Evidence for Long-Timescale Patterns of Synaptic Inputs in CA1 of Awake Behaving Mice.

    Science.gov (United States)

    Kolb, Ilya; Talei Franzesi, Giovanni; Wang, Michael; Kodandaramaiah, Suhasa B; Forest, Craig R; Boyden, Edward S; Singer, Annabelle C

    2018-02-14

    Repeated sequences of neural activity are a pervasive feature of neural networks in vivo and in vitro In the hippocampus, sequential firing of many neurons over periods of 100-300 ms reoccurs during behavior and during periods of quiescence. However, it is not known whether the hippocampus produces longer sequences of activity or whether such sequences are restricted to specific network states. Furthermore, whether long repeated patterns of activity are transmitted to single cells downstream is unclear. To answer these questions, we recorded intracellularly from hippocampal CA1 of awake, behaving male mice to examine both subthreshold activity and spiking output in single neurons. In eight of nine recordings, we discovered long (900 ms) reoccurring subthreshold fluctuations or "repeats." Repeats generally were high-amplitude, nonoscillatory events reoccurring with 10 ms precision. Using statistical controls, we determined that repeats occurred more often than would be expected from unstructured network activity (e.g., by chance). Most spikes occurred during a repeat, and when a repeat contained a spike, the spike reoccurred with precision on the order of ≤20 ms, showing that long repeated patterns of subthreshold activity are strongly connected to spike output. Unexpectedly, we found that repeats occurred independently of classic hippocampal network states like theta oscillations or sharp-wave ripples. Together, these results reveal surprisingly long patterns of repeated activity in the hippocampal network that occur nonstochastically, are transmitted to single downstream neurons, and strongly shape their output. This suggests that the timescale of information transmission in the hippocampal network is much longer than previously thought. SIGNIFICANCE STATEMENT We found long (≥900 ms), repeated, subthreshold patterns of activity in CA1 of awake, behaving mice. These repeated patterns ("repeats") occurred more often than expected by chance and with 10 ms

  3. Effects of contract-relax vs static stretching on stretch-induced strength loss and length-tension relationship

    DEFF Research Database (Denmark)

    Balle, S S; Magnusson, S P; McHugh, M P

    2015-01-01

    The purpose of this study was to determine the acute effects of contract-relax stretching (CRS) vs static stretching (SS) on strength loss and the length-tension relationship. We hypothesized that there would be a greater muscle length-specific effect of CRS vs SS. Isometric hamstring strength wa...

  4. Electrical stimulation of the sacral dorsal gray commissure evokes relaxation of the external urethral sphincter in the cat

    NARCIS (Netherlands)

    Blok, Bertil F.M.; Maarseveen, Jos T.P.W.; Holstege, Gert

    1998-01-01

    Stimulation of the pontine micturition center (PMC) results in micturition, i.e. an immediate relaxation of the urethral sphincter and a contraction of the detrusor muscle of the bladder. The PMC generates the bladder contraction by way of a direct excitatory pathway to the parasympathetic bladder

  5. Stress relaxation under cyclic electron irradiation

    International Nuclear Information System (INIS)

    Bystrov, L.N.; Reznitskij, M.E.

    1990-01-01

    The kinetics of deformation process in a relaxating sample under 2 MeV electron cyclic irradiation was studied experimentally. The Al-Mg alloys with controllable and different (in dislocation density precipitate presence and their character) structure were used in experiments. It was established that after the beam was switched on the deformation rate increased sharply and then, during prolonged irradiation, in a gradual manner. After the switching-off the relaxation rate decreases by jumps up to values close to extrapolated rates of pre-radiation relaxation. The exhibition of these effects with radiation switching-off and switchin-on is dependent on the initial rate of thermal relaxation, the test temperature, the preliminary cold deformation and the dominating deformation dislocation mechanism. The preliminary cold deformation and test temperature elevation slightly decrease the effect of instantaneous relaxation acceleration with the irradiation switch-on. 17 refs., 5 figs

  6. Relaxation dynamics following transition of solvated electrons

    International Nuclear Information System (INIS)

    Barnett, R.B.; Landman, U.; Nitzan, A.

    1989-01-01

    Relaxation dynamics following an electronic transition of an excess solvated electron in clusters and in bulk water is studied using an adiabatic simulation method. In this method the solvent evolves classically and the electron is constrained to a specified state. The coupling between the solvent and the excess electron is evaluated via the quantum expectation value of the electron--water molecule interaction potential. The relaxation following excitation (or deexcitation) is characterized by two time scales: (i) a very fast (/similar to/20--30 fs) one associated with molecular rotations in the first solvation shell about the electron, and (ii) a slower stage (/similar to/200 fs), which is of the order of the longitudinal dielectric relaxation time. The fast relaxation stage exhibits an isotope effect. The spectroscopical consequences of the relaxation dynamics are discussed

  7. Anomalous enthalpy relaxation in vitreous silica

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    2015-01-01

    scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling) has impact on enthalpy relaxation in glass. Here, we find that vitreous silica (as a strong system) exhibits striking anomalies in both glass transition and enthalpy...... relaxation compared to fragile oxide systems. The anomalous enthalpy relaxation of vitreous silica is discovered by performing the hyperquenching-annealing-calorimetry experiments. We argue that the strong systems like vitreous silica and vitreous Germania relax in a structurally cooperative manner, whereas...... the fragile ones do in a structurally independent fashion. We discuss the origin of the anomalous enthalpy relaxation in the HQ vitreous silica....

  8. Vibrational and Rotational Energy Relaxation in Liquids

    DEFF Research Database (Denmark)

    Petersen, Jakob

    Vibrational and rotational energy relaxation in liquids are studied by means of computer simulations. As a precursor for studying vibrational energy relaxation of a solute molecule subsequent to the formation of a chemical bond, the validity of the classical Bersohn-Zewail model for describing......, the vibrational energy relaxation of I2 subsequent to photodissociation and recombination in CCl4 is studied using classical Molecular Dynamics simulations. The vibrational relaxation times and the time-dependent I-I pair distribution function are compared to new experimental results, and a qualitative agreement...... is found in both cases. Furthermore, the rotational energy relaxation of H2O in liquid water is studied via simulations and a power-and-work analysis. The mechanism of the energy transfer from the rotationally excited H2O molecule to its water neighbors is elucidated, i.e. the energy-accepting degrees...

  9. Cross-relaxation solid state lasers

    International Nuclear Information System (INIS)

    Antipenko, B.M.

    1989-01-01

    Cross-relaxation functional diagrams provide a high quantum efficiency for pumping bands of solid state laser media and a low waste heat. A large number of the cross-relaxation mechanisms for decay rare earth excited states in crystals have been investigated. These investigations have been a starting-point for development of the cross-relaxation solid state lasers. For example, the cross-relaxation interactions, have been used for the laser action development of LiYF 4 :Gd-Tb. These interactions are important elements of the functional diagrams of the 2 μm Ho-doped media sensitized with Er and Tm and the 3 μm Er-doped media. Recently, new efficient 2 μm laser media with cross-relaxation pumping diagrams have been developed. Physical aspects of these media are the subject of this paper. A new concept of the Er-doped medium, sensitized with Yb, is illustrated

  10. Functional Echomyography of the human denervated muscle: first results

    Directory of Open Access Journals (Sweden)

    Riccardo Zanato

    2011-03-01

    Full Text Available In this study we followed with ultrasound three patients with permanent denervation to evaluate changes in morphology, thickness, contraction and vascularisation of muscles undergoing the home-based electrical stimulation program of the Rise2-Italy project. During a period of 1 year for the first subject, 6 months for the second subject and 3 months for the third subject we studied with ultrasound the denervated muscle comparing it (if possible to the contralateral normal muscle. We evaluated: 1. Changes in morphology and sonographic structure of the pathologic muscle; 2. Muscular thickness in response to the electrical stimulation therapy; 3. Short-term modifications in muscle perfusion and arterial flow patterns after stimulation; 4. Contraction-relaxation kinetic induced by volitional activity or electrical stimulation. Morphology and ultrasonographic structure of the denervated muscles changed during the period of stimulation from a pattern typical of complete muscular atrophy to a pattern which might be considered “normal” when detected in an old patient. Thickness improved significantly more in the middle third than in the proximal and distal third of the denervated muscle, reaching in the last measurements of the first subject approximately the same thickness as the contralateral normal muscle. In all the measurements done within this study, arterial flow of the denervated muscle showed at rest a low-resistance pattern with Doppler Ultra Sound (US, and a pulsed pattern after electrical stimulation. The stimulation- induced pattern is similar to the trifasic high-resistance pattern of the normal muscle. Contraction- relaxation kinetic, measured by recording the muscular movements during electrical stimulation, showed an abnormal behaviour of the denervated muscle during the relaxation phase, which resulted to be significantly longer than in normal muscle (880 msec in the denervated muscle vs 240 msec in the contralateral normal one

  11. L-acetylcarnitine enhances functional muscle re-innervation.

    Science.gov (United States)

    Pettorossi, V E; Brunetti, O; Carobi, C; Della Torre, G; Grassi, S

    1991-01-01

    The efficacy of L-acetylcarnitine and L-carnitine treatment on motor re-innervation was analyzed by evaluating different muscular parameters describing functional muscle recovery after denervation and re-innervation. The results show that L-acetylcarnitine markedly enhances functional muscle re-innervation, which on the contrary is unaffected by L-carnitine. The medial gastrocnemius muscle was denervated by cutting the nerve at the muscle entry point. After 20 days the sectioned nerve was resutured into the medial gastrocnemius muscle, and the extent of re-innervation was monitored 45 days later. L-acetylcarnitine-treated animals show significantly higher twitch and tetanic tensions of re-innervated muscle. Furthermore the results, obtained by analysing the twitch time to peak and tetanic contraction-relaxation times, suggest that L-acetylcarnitine mostly affects the functional re-innervation of slow motor units. The possible mechanisms by which L-acetylcarnitine facilitates such motor and nerve recovery are discussed.

  12. Muscle activity pattern dependent pain development and alleviation

    DEFF Research Database (Denmark)

    Sjøgaard, Gisela; Søgaard, Karen

    2014-01-01

    Muscle activity is for decades considered to provide health benefits irrespectively of the muscle activity pattern performed and whether it is during e.g. sports, transportation, or occupational work tasks. Accordingly, the international recommendations for public health-promoting physical activity...... do not distinguish between occupational and leisure time physical activity. However, in this body of literature, attention has not been paid to the extensive documentation on occupational physical activity imposing a risk of impairment of health - in particular musculoskeletal health in terms...... during physical activities at leisure and sport the motor recruitment patterns are more dynamic including regularly relatively high muscle forces - also activating type 2 muscles fibers - as well as periods of full relaxation even of the type 1 muscle fibers. Such activity is unrelated to muscle pain...

  13. Relaxation Therapy on Fetal Outcomes in Complicated Pregnancies Suffering Sleep Disorders: A Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    azar nematollahi

    2016-10-01

    Full Text Available Background: Sleep disorders like snoring, mouth breathing, and insomnia are frequent in pregnancy and studies have shown that poor sleep is linked to obstetric complications. Muscle relaxation technique is an effective method used for improving sleep quality. The purpose of this study was to determine the effect of muscle relaxation technique on fetal outcomes in complicated pregnancies with sleep disorders. Methods: This study was performed as a clinical trial on 160 pregnant women who suffered from preeclampsia and gestational diabetes. The participants filled the Pittsburgh Sleep Quality Index (PSQI in order to measure the quality and patterns of their sleep. The participants with the total score of 5 or more were included in the present study. Intervention group were asked to use muscle relaxation technique twice a week at home for 8 weeks alongside the routine care. Study variables included sleep quality, Apgar scores, birth weight, levels of Interleukin- 6 (IL- 6, as well as umbilical cord PH and PO2. Results: The mean score of PSQI before the intervention was 9.28±4.16 and 9.18±3.06 in the intervention and control groups without a significant difference (P=0.6, respectively. However, PSQI global score of the experimental group was smaller than the control group at the end of the study (P<0.001. Also, birth weight (P=0.04, Apgar score (P=0.01, and umbilical cord blood po2 (P=0.03 and PH (P=0.01 were higher, and IL-6 (P=0.04 was smaller in the experimental group compared to the control group. Conclusion: The results of this study showed that muscle relaxation, as a simple, inexpensive and safe method, can improve the fetal outcomes such as birth weight, Apgar score, cord blood po2, and cord blood PH, and also it leads to lower IL-6 in complicated pregnancies.

  14. Magnetic Resonance Fingerprinting with short relaxation intervals.

    Science.gov (United States)

    Amthor, Thomas; Doneva, Mariya; Koken, Peter; Sommer, Karsten; Meineke, Jakob; Börnert, Peter

    2017-09-01

    The aim of this study was to investigate a technique for improving the performance of Magnetic Resonance Fingerprinting (MRF) in repetitive sampling schemes, in particular for 3D MRF acquisition, by shortening relaxation intervals between MRF pulse train repetitions. A calculation method for MRF dictionaries adapted to short relaxation intervals and non-relaxed initial spin states is presented, based on the concept of stationary fingerprints. The method is applicable to many different k-space sampling schemes in 2D and 3D. For accuracy analysis, T 1 and T 2 values of a phantom are determined by single-slice Cartesian MRF for different relaxation intervals and are compared with quantitative reference measurements. The relevance of slice profile effects is also investigated in this case. To further illustrate the capabilities of the method, an application to in-vivo spiral 3D MRF measurements is demonstrated. The proposed computation method enables accurate parameter estimation even for the shortest relaxation intervals, as investigated for different sampling patterns in 2D and 3D. In 2D Cartesian measurements, we achieved a scan acceleration of more than a factor of two, while maintaining acceptable accuracy: The largest T 1 values of a sample set deviated from their reference values by 0.3% (longest relaxation interval) and 2.4% (shortest relaxation interval). The largest T 2 values showed systematic deviations of up to 10% for all relaxation intervals, which is discussed. The influence of slice profile effects for multislice acquisition is shown to become increasingly relevant for short relaxation intervals. In 3D spiral measurements, a scan time reduction of 36% was achieved, maintaining the quality of in-vivo T1 and T2 maps. Reducing the relaxation interval between MRF sequence repetitions using stationary fingerprint dictionaries is a feasible method to improve the scan efficiency of MRF sequences. The method enables fast implementations of 3D spatially

  15. Corroborative evidences of TV γ -scaling of the α-relaxation originating from the primitive relaxation/JG β relaxation

    Science.gov (United States)

    Ngai, K. L.; Paluch, M.

    2017-12-01

    Successful thermodynamic scaling of the structural alpha-relaxation time or transport coefficients of glass-forming liquids determined at various temperatures T and pressures P means the data conform to a single function of the product variable TVgamma, where V is the specific volume and gamma is a material specific constant. In the past two decades we have witnessed successful TVgamma-scaling in many molecular, polymeric, and even metallic glass-formers, and gamma is related to the slope of the repulsive part of the intermolecular potential. The advances made indicate TVgamma-scaling is an important aspect of the dynamic and thermodynamic properties of glass-formers. In this paper we show the origin of TVgamma-scaling is not from the structural alpha-relaxation time. Instead it comes from its precursor, the Johari-Goldstein beta-relaxation or the primitive relaxation of the Coupling Model and their relaxation times or tau_0 respectively. It is remarkable that all relaxation times are functions of TVgamma with the same gama, as well as the fractional exponent of the Kohlrausch correlation function of the structural alpha-relaxation. We arrive at this conclusion convincingly based on corroborative evidences from a number of experiments and molecular dynamics simulations performed on a wide variety of glass-formers and in conjunction with consistency with the predictions of the Coupling Model.

  16. How does tissue preparation affect skeletal muscle transverse isotropy?

    Science.gov (United States)

    Wheatley, Benjamin B.; Odegard, Gregory M.; Kaufman, Kenton R.; Haut Donahue, Tammy L.

    2016-01-01

    The passive tensile properties of skeletal muscle play a key role in its physiological function. Previous research has identified conflicting reports of muscle transverse isotropy, with some data suggesting the longitudinal direction is stiffest, while others show the transverse direction is stiffest. Accurate constitutive models of skeletal muscle must be employed to provide correct recommendations for and observations of clinical methods. The goal of this work was to identify transversely isotropic tensile muscle properties as a function of post mortem handling. Six pairs of tibialis anterior muscles were harvested from Giant Flemish rabbits and split into two groups: fresh testing (within four hours post mortem), and non-fresh testing (subject to delayed testing and a freeze/thaw cycle). Longitudinal and transverse samples were removed from each muscle and tested to identify tensile modulus and relaxation behavior. Longitudinal non-fresh samples exhibited a higher initial modulus value and faster relaxation than longitudinal fresh, transverse fresh, and transverse rigor samples (p<0.05), while longitudinal fresh samples were less stiff at lower strain levels than longitudinal non-fresh, transverse fresh, and transverse non-fresh samples (p<0.05), but exhibited more nonlinear behavior. While fresh skeletal muscle exhibits a higher transverse modulus than longitudinal modulus, discrepancies in previously published data may be the result of a number of differences in experimental protocol. Constitutive modeling of fresh muscle should reflect these data by identifying the material as truly transversely isotropic and not as an isotropic matrix reinforced with fibers. PMID:27425557

  17. The embodiment of tourism among bisexually-behaving Dominican male sex workers.

    Science.gov (United States)

    Padilla, Mark B

    2008-10-01

    While theories of "structure" and social inequality have increasingly informed global health efforts for HIV prevention--with growing recognition of the linkages between large-scale political and economic factors in the distribution and impact of the HIV/AIDS epidemic--there is still little theorization of precisely how structural factors shape the very bodies and sexualities of specific populations and groups. In order to extend the theoretical understanding of these macro-micro linkages, this article examines how the growth of the tourism industry in the Dominican Republic has produced sexual practices and identities that reflect both the influence of large-scale structural processes and the resistant responses of local individuals. Drawing on social science theories of political economy, embodiment, and authenticity, I argue that an understanding of patterns of sexuality and HIV risk in the region requires analysis of how political-economic transformations related to tourism intersect with the individual experiences and practices of sexuality on the ground. The analysis draws on long-term ethnographic research with bisexually behaving male sex workers in two cities in the Dominican Republic, including participant observation, in-depth interviews, focus groups, and surveys. By examining the global and local values placed on these men's bodies and the ways sex workers use their bodies to broker tourists' pleasure, we may better understand how the large-scale structures of the tourism industry are linked to the specific meanings and practices of sexuality.

  18. Social class, power, and selfishness: when and why upper and lower class individuals behave unethically.

    Science.gov (United States)

    Dubois, David; Rucker, Derek D; Galinsky, Adam D

    2015-03-01

    Are the rich more unethical than the poor? To answer this question, the current research introduces a key conceptual distinction between selfish and unethical behavior. Based on this distinction, the current article offers 2 novel findings that illuminate the relationship between social class and unethical behavior. First, the effects of social class on unethical behavior are not invariant; rather, the effects of social class are moderated by whether unethical behavior benefits the self or others. Replicating past work, social class positively predicted unethical behavior; however, this relationship was only observed when that behavior was self-beneficial. When unethical behavior was performed to benefit others, social class negatively predicted unethical behavior; lower class individuals were more likely than upper class individuals to engage in unethical behavior. Overall, social class predicts people's tendency to behave selfishly, rather than predicting unethical behavior per se. Second, individuals' sense of power drove the effects of social class on unethical behavior. Evidence for this relationship was provided in three forms. First, income, but not education level, predicted unethical behavior. Second, feelings of power mediated the effect of social class on unethical behavior, but feelings of status did not. Third, two distinct manipulations of power produced the same moderation by self-versus-other beneficiary as was found with social class. The current theoretical framework and data both synthesize and help to explain a range of findings in the social class and power literatures. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  19. Solving the economic dispatch problem with a modified quantum-behaved particle swarm optimization method

    International Nuclear Information System (INIS)

    Sun Jun; Fang Wei; Wang Daojun; Xu Wenbo

    2009-01-01

    In this paper, a modified quantum-behaved particle swarm optimization (QPSO) method is proposed to solve the economic dispatch (ED) problem in power systems, whose objective is to simultaneously minimize the generation cost rate while satisfying various equality and inequality constraints. The proposed method, denoted as QPSO-DM, combines the QPSO algorithm with differential mutation operation to enhance the global search ability of the algorithm. Many nonlinear characteristics of the generator, such as ramp rate limits, prohibited operating zones, and nonsmooth cost functions are considered when the proposed method is used in practical generator operation. The feasibility of the QPSO-DM method is demonstrated by three different power systems. It is compared with the QPSO, the differential evolution (DE), the particle swarm optimization (PSO), and the genetic algorithm (GA) in terms of the solution quality, robustness and convergence property. The simulation results show that the proposed QPSO-DM method is able to obtain higher quality solutions stably and efficiently in the ED problem than any other tested optimization algorithm.

  20. Solving the economic dispatch problem with a modified quantum-behaved particle swarm optimization method

    Energy Technology Data Exchange (ETDEWEB)

    Jun Sun; Wei Fang; Daojun Wang; Wenbo Xu [School of Information Technology, Jiangnan Univ., Wuxi, Jiangsu 214122 (China)

    2009-12-15

    In this paper, a modified quantum-behaved particle swarm optimization (QPSO) method is proposed to solve the economic dispatch (ED) problem in power systems, whose objective is to simultaneously minimize the generation cost rate while satisfying various equality and inequality constraints. The proposed method, denoted as QPSO-DM, combines the QPSO algorithm with differential mutation operation to enhance the global search ability of the algorithm. Many nonlinear characteristics of the generator, such as ramp rate limits, prohibited operating zones, and nonsmooth cost functions are considered when the proposed method is used in practical generator operation. The feasibility of the QPSO-DM method is demonstrated by three different power systems. It is compared with the QPSO, the differential evolution (DE), the particle swarm optimization (PSO), and the genetic algorithm (GA) in terms of the solution quality, robustness and convergence property. The simulation results show that the proposed QPSO-DM method is able to obtain higher quality solutions stably and efficiently in the ED problem than any other tested optimization algorithm. (author)

  1. How Do Children Behave Regarding Their Birth Order in Dental Setting?

    Science.gov (United States)

    Ghaderi, Faezeh; Fijan, Soleiman; Hamedani, Shahram

    2015-12-01

    Prediction of child cooperation level in dental setting is an important issue for a dentist to select the proper behavior management method. Many psychological studies have emphasized the effect of birth order on patient behavior and personality; however, only a few researches evaluated the effect of birth order on child's behavior in dental setting. This study was designed to evaluate the influence of children ordinal position on their behavior in dental setting. A total of 158 children with at least one primary mandibular molar needing class I restoration were selected. Children were classified based on the ordinal position; first, middle, or last child as well as single child. A blinded examiner recorded the pain perception of children during injection based on Visual Analogue Scale (VAS) and Sound, Eye and Movement (SEM) scale. To assess the child's anxiety, the questionnaire known as "Dental Subscale of the Children's Fear Survey Schedule" (CFSS-DS) was employed. The results showed that single children were significantly less cooperative and more anxious than the other children (p<0.001). The middle children were significantly more cooperative in comparison with the other child's position (p< 0.001). Single child may behave less cooperatively in dental setting. The order of child birth must also be considered in prediction of child's behavior for behavioral management.

  2. Dopamine Modulates Delta-Gamma Phase-Amplitude Coupling in the Prefrontal Cortex of Behaving Rats

    Science.gov (United States)

    Andino-Pavlovsky, Victoria; Souza, Annie C.; Scheffer-Teixeira, Robson; Tort, Adriano B. L.; Etchenique, Roberto; Ribeiro, Sidarta

    2017-01-01

    Dopamine release and phase-amplitude cross-frequency coupling (CFC) have independently been implicated in prefrontal cortex (PFC) functioning. To causally investigate whether dopamine release affects phase-amplitude comodulation between different frequencies in local field potentials (LFP) recorded from the medial PFC (mPFC) of behaving rats, we used RuBiDopa, a light-sensitive caged compound that releases the neurotransmitter dopamine when irradiated with visible light. LFP power did not change in any frequency band after the application of light-uncaged dopamine, but significantly strengthened phase-amplitude comodulation between delta and gamma oscillations. Saline did not exert significant changes, while injections of dopamine and RuBiDopa produced a slow increase in comodulation for several minutes after the injection. The results show that dopamine release in the medial PFC shifts phase-amplitude comodulation from theta-gamma to delta-gamma. Although being preliminary results due to the limitation of the low number of animals present in this study, our findings suggest that dopamine-mediated modification of the frequencies involved in comodulation could be a mechanism by which this neurotransmitter regulates functioning in mPFC. PMID:28536507

  3. Seeing the whole picture: A comprehensive imaging approach to functional mapping of circuits in behaving zebrafish.

    Science.gov (United States)

    Feierstein, C E; Portugues, R; Orger, M B

    2015-06-18

    In recent years, the zebrafish has emerged as an appealing model system to tackle questions relating to the neural circuit basis of behavior. This can be attributed not just to the growing use of genetically tractable model organisms, but also in large part to the rapid advances in optical techniques for neuroscience, which are ideally suited for application to the small, transparent brain of the larval fish. Many characteristic features of vertebrate brains, from gross anatomy down to particular circuit motifs and cell-types, as well as conserved behaviors, can be found in zebrafish even just a few days post fertilization, and, at this early stage, the physical size of the brain makes it possible to analyze neural activity in a comprehensive fashion. In a recent study, we used a systematic and unbiased imaging method to record the pattern of activity dynamics throughout the whole brain of larval zebrafish during a simple visual behavior, the optokinetic response (OKR). This approach revealed the broadly distributed network of neurons that were active during the behavior and provided insights into the fine-scale functional architecture in the brain, inter-individual variability, and the spatial distribution of behaviorally relevant signals. Combined with mapping anatomical and functional connectivity, targeted electrophysiological recordings, and genetic labeling of specific populations, this comprehensive approach in zebrafish provides an unparalleled opportunity to study complete circuits in a behaving vertebrate animal. Copyright © 2014. Published by Elsevier Ltd.

  4. Glomerular barrier behaves as an atomically precise bandpass filter in a sub-nanometre regime

    Science.gov (United States)

    Du, Bujie; Jiang, Xingya; Das, Anindita; Zhou, Qinhan; Yu, Mengxiao; Jin, Rongchao; Zheng, Jie

    2017-11-01

    The glomerular filtration barrier is known as a 'size cutoff' slit, which retains nanoparticles or proteins larger than 6-8 nm in the body and rapidly excretes smaller ones through the kidneys. However, in the sub-nanometre size regime, we have found that this barrier behaves as an atomically precise 'bandpass' filter to significantly slow down renal clearance of few-atom gold nanoclusters (AuNCs) with the same surface ligands but different sizes (Au18, Au15 and Au10-11). Compared to Au25 (∼1.0 nm), just few-atom decreases in size result in four- to ninefold reductions in renal clearance efficiency in the early elimination stage, because the smaller AuNCs are more readily trapped by the glomerular glycocalyx than larger ones. This unique in vivo nano-bio interaction in the sub-nanometre regime also slows down the extravasation of sub-nanometre AuNCs from normal blood vessels and enhances their passive targeting to cancerous tissues through an enhanced permeability and retention effect. This discovery highlights the size precision in the body's response to nanoparticles and opens a new pathway to develop nanomedicines for many diseases associated with glycocalyx dysfunction.

  5. Charging and switching of ferroelectrets: how much can ferroelectrets behave like ferroelectrics?

    International Nuclear Information System (INIS)

    Schwoediauer, R.; Graz, I.; Bauer, S.

    2004-01-01

    Dielectrics with good charge storage capability, so called charge electrets, are non or weakly-polar materials. Despite their non-polar nature porous charge electrets with internally charged surfaces can exhibit very pronounced piezoelectricity. Such systems have been termed 'ferroelectrets' and they have been receiving growing attention over the last few years. Their puzzling and unexpected features resemble very much those normally known from traditional ferroelectrics: ferroelectrets are piezo- and pyroelectric, their polarization can be reversed by means of an external field and electrical as well as mechanical hysteresis loops were observed. As conventional ferroelectrics are different and more complicated than ferromagnets, so are ferroelectrets different and more complex than most ferroelectrics. Here we report about the very different charging and switching mechanism in ferroelectrets, both in simple model-systems and in less simple foam structures. These mechanisms are crucial and form the basis for the striking phenomenological similarities to ferroelectrics. We also want to address some of the specific peculiarities and pitfalls related to present ferroelectrets and their characterization. Interfacial charge injection at high electric fields and anelastic non-linearities, for instance, can be the cause for false ferroelectric-like hysteresis effects which do not reflect any polarization reversal. Our contribution is an attempt towards a more comprehensive picture of how much ferroelectrets behave like ferroelectrics. (author)

  6. A mathematical model for pressure-based organs behaving as biological pressure vessels.

    Science.gov (United States)

    Casha, Aaron R; Camilleri, Liberato; Gauci, Marilyn; Gatt, Ruben; Sladden, David; Chetcuti, Stanley; Grima, Joseph N

    2018-04-26

    We introduce a mathematical model that describes the allometry of physical characteristics of hollow organs behaving as pressure vessels based on the physics of ideal pressure vessels. The model was validated by studying parameters such as body and organ mass, systolic and diastolic pressures, internal and external dimensions, pressurization energy and organ energy output measurements of pressure-based organs in a wide range of mammals and birds. Seven rules were derived that govern amongst others, lack of size efficiency on scaling to larger organ sizes, matching organ size in the same species, equal relative efficiency in pressurization energy across species and direct size matching between organ mass and mass of contents. The lung, heart and bladder follow these predicted theoretical relationships with a similar relative efficiency across various mammalian and avian species; an exception is cardiac output in mammals with a mass exceeding 10kg. This may limit massive body size in mammals, breaking Cope's rule that populations evolve to increase in body size over time. Such a limit was not found in large flightless birds exceeding 100kg, leading to speculation about unlimited dinosaur size should dinosaurs carry avian-like cardiac characteristics. Copyright © 2018. Published by Elsevier Ltd.

  7. Correction to: Direct effects of doxorubicin on skeletal muscle contribute to fatigue

    NARCIS (Netherlands)

    Norren, van K.; Helvoort, van A.; Agriles, J.M.; Tuijl, van S.; Arts, K.; Gorselink, M.; Laviano, A.; Kegler, D.; Haagsman, H.P.; Beek, van der E.M.

    2009-01-01

    Chemotherapy-induced fatigue is a multidimensional symptom. Oxidative stress has been proposed as a working mechanism for anthracycline-induced cardiotoxicity. In this study, doxorubicin (DOX) was tested on skeletal muscle function. Doxorubicin induced impaired ex vivo skeletal muscle relaxation

  8. Relaxing a large cosmological constant

    International Nuclear Information System (INIS)

    Bauer, Florian; Sola, Joan; Stefancic, Hrvoje

    2009-01-01

    The cosmological constant (CC) problem is the biggest enigma of theoretical physics ever. In recent times, it has been rephrased as the dark energy (DE) problem in order to encompass a wider spectrum of possibilities. It is, in any case, a polyhedric puzzle with many faces, including the cosmic coincidence problem, i.e. why the density of matter ρ m is presently so close to the CC density ρ Λ . However, the oldest, toughest and most intriguing face of this polyhedron is the big CC problem, namely why the measured value of ρ Λ at present is so small as compared to any typical density scale existing in high energy physics, especially taking into account the many phase transitions that our Universe has undergone since the early times, including inflation. In this Letter, we propose to extend the field equations of General Relativity by including a class of invariant terms that automatically relax the value of the CC irrespective of the initial size of the vacuum energy in the early epochs. We show that, at late times, the Universe enters an eternal de Sitter stage mimicking a tiny positive cosmological constant. Thus, these models could be able to solve the big CC problem without fine-tuning and have also a bearing on the cosmic coincidence problem. Remarkably, they mimic the ΛCDM model to a large extent, but they still leave some characteristic imprints that should be testable in the next generation of experiments.

  9. Distinct mechanisms of relaxation to bioactive components from chamomile species in porcine isolated blood vessels

    International Nuclear Information System (INIS)

    Roberts, R.E.; Allen, S.; Chang, A.P.Y.; Henderson, H.; Hobson, G.C.; Karania, B.; Morgan, K.N.; Pek, A.S.Y.; Raghvani, K.; Shee, C.Y.; Shikotra, J.; Street, E.; Abbas, Z.; Ellis, K.; Heer, J.K.; Alexander, S.P.H.

    2013-01-01

    German chamomile (Matricaria recutita L.), a widely-used herbal medicine, has been reported to have a wide range of biological effects, including smooth muscle relaxation. The aim of this study was to compare the effects of representative compounds from chamomile (apigenin, luteolin, (−)-α-bisabolol, farnesene, umbelliferone; 3–30 μM) on vascular tone using porcine coronary and splenic arteries mounted for isometric tension recording in isolated tissue baths and precontracted with the thromboxane-mimetic U46619. Apigenin, luteolin, and (−)-α-bisabolol produced slow, concentration-dependent relaxations in both the coronary and splenic arteries that were not blocked by inhibition of nitric oxide synthase or potassium channels. Removal of extracellular calcium inhibited the relaxations to all three compounds, and these compounds also inhibited calcium re-addition-evoked contractions, indicating that the relaxation response may be mediated through inhibition of calcium influx. Apigenin and luteolin, but not (−)-α-bisabolol, enhanced the relaxation to the nitric oxide donor sodium nitroprusside, indicating that apigenin and luteolin may act to regulate cyclic GMP levels. Umbelliferone produced a rapid, transient relaxation in the splenic artery, but not the coronary artery, that was inhibited by L-NAME and removal of the endothelium, suggesting an influence on nitric oxide production. Farnesene, at concentrations up to 30 μM, was without effect in either blood vessel. In conclusion, hydroxylated compounds (apigenin, luteolin and (−)-α-bisabolol) found in chamomile all caused a slow relaxation of isolated blood vessels through an effect on calcium influx. Umbelliferone, on the other hand, produced a rapid, transient relaxation dependent upon release of nitric oxide from the endothelium. - Highlights: • Apigenin, luteolin, and (-)-α-bisabolol are present in chamomile. • They produced slow, concentration-dependent relaxations in arteries. • These

  10. Distinct mechanisms of relaxation to bioactive components from chamomile species in porcine isolated blood vessels

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, R.E., E-mail: Richard.roberts@nottingham.ac.uk; Allen, S.; Chang, A.P.Y.; Henderson, H.; Hobson, G.C.; Karania, B.; Morgan, K.N.; Pek, A.S.Y.; Raghvani, K.; Shee, C.Y.; Shikotra, J.; Street, E.; Abbas, Z.; Ellis, K.; Heer, J.K.; Alexander, S.P.H., E-mail: steve.alexander@nottingham.ac.uk

    2013-11-01

    German chamomile (Matricaria recutita L.), a widely-used herbal medicine, has been reported to have a wide range of biological effects, including smooth muscle relaxation. The aim of this study was to compare the effects of representative compounds from chamomile (apigenin, luteolin, (−)-α-bisabolol, farnesene, umbelliferone; 3–30 μM) on vascular tone using porcine coronary and splenic arteries mounted for isometric tension recording in isolated tissue baths and precontracted with the thromboxane-mimetic U46619. Apigenin, luteolin, and (−)-α-bisabolol produced slow, concentration-dependent relaxations in both the coronary and splenic arteries that were not blocked by inhibition of nitric oxide synthase or potassium channels. Removal of extracellular calcium inhibited the relaxations to all three compounds, and these compounds also inhibited calcium re-addition-evoked contractions, indicating that the relaxation response may be mediated through inhibition of calcium influx. Apigenin and luteolin, but not (−)-α-bisabolol, enhanced the relaxation to the nitric oxide donor sodium nitroprusside, indicating that apigenin and luteolin may act to regulate cyclic GMP levels. Umbelliferone produced a rapid, transient relaxation in the splenic artery, but not the coronary artery, that was inhibited by L-NAME and removal of the endothelium, suggesting an influence on nitric oxide production. Farnesene, at concentrations up to 30 μM, was without effect in either blood vessel. In conclusion, hydroxylated compounds (apigenin, luteolin and (−)-α-bisabolol) found in chamomile all caused a slow relaxation of isolated blood vessels through an effect on calcium influx. Umbelliferone, on the other hand, produced a rapid, transient relaxation dependent upon release of nitric oxide from the endothelium. - Highlights: • Apigenin, luteolin, and (-)-α-bisabolol are present in chamomile. • They produced slow, concentration-dependent relaxations in arteries. • These

  11. Stem cell antigen-1 in skeletal muscle function.

    Science.gov (United States)

    Bernstein, Harold S; Samad, Tahmina; Cholsiripunlert, Sompob; Khalifian, Saami; Gong, Wenhui; Ritner, Carissa; Aurigui, Julian; Ling, Vivian; Wilschut, Karlijn J; Bennett, Stephen; Hoffman, Julien; Oishi, Peter

    2013-08-15

    Stem cell antigen-1 (Sca-1) is a member of the Ly-6 multigene family encoding highly homologous, glycosyl-phosphatidylinositol-anchored membrane proteins. Sca-1 is expressed on muscle-derived stem cells and myogenic precursors recruited to sites of muscle injury. We previously reported that inhibition of Sca-1 expression stimulated myoblast proliferation in vitro and regulated the tempo of muscle repair in vivo. Despite its function in myoblast expansion during muscle repair, a role for Sca-1 in normal, post-natal muscle has not been thoroughly investigated. We systematically compared Sca-1-/- (KO) and Sca-1+/+ (WT) mice and hindlimb muscles to elucidate the tissue, contractile, and functional effects of Sca-1 in young and aging animals. Comparison of muscle volume, fibrosis, myofiber cross-sectional area, and Pax7+ myoblast number showed little differences between ages or genotypes. Exercise protocols, however, demonstrated decreased stamina in KO versus WT mice, with young KO mice achieving results similar to aging WT animals. In addition, KO mice did not improve with practice, while WT animals demonstrated conditioning over time. Surprisingly, myomechanical analysis of isolated muscles showed that KO young muscle generated more force and experienced less fatigue. However, KO muscle also demonstrated incomplete relaxation with fatigue. These findings suggest that Sca-1 is necessary for muscle conditioning with exercise, and that deficient conditioning in Sca-1 KO animals becomes more pronounced with age.

  12. Muscle Sensor Model Using Small Scale Optical Device for Pattern Recognitions

    Directory of Open Access Journals (Sweden)

    Kreangsak Tamee

    2013-01-01

    Full Text Available A new sensor system for measuring contraction and relaxation of muscles by using a PANDA ring resonator is proposed. The small scale optical device is designed and configured to perform the coupling effects between the changes in optical device phase shift and human facial muscle movement, which can be used to form the relationship between optical phase shift and muscle movement. By using the Optiwave and MATLAB programs, the results obtained have shown that the measurement of the contraction and relaxation of muscles can be obtained after the muscle movements, in which the unique pattern of individual muscle movement from facial expression can be established. The obtained simulation results, that is, interference signal patterns, can be used to form the various pattern recognitions, which are useful for the human machine interface and the human computer interface application and discussed in detail.

  13. Relaxation of polarized nuclei in superconducting rhodium

    DEFF Research Database (Denmark)

    Knuuttila, T.A.; Tuoriniemi, J.T.; Lefmann, K.

    2000-01-01

    Nuclear spin lattice relaxation rates were measured in normal and superconducting (sc) rhodium with nuclear polarizations up to p = 0.55. This was sufficient to influence the sc state of Rh, whose T, and B-c, are exceptionally low. Because B-c ... is unchanged, the nuclear spin entropy was fully sustained across the sc transition. The relaxation in the sc state was slower at all temperatures without the coherence enhancement close to T-c. Nonzero nuclear polarization strongly reduced the difference between the relaxation rates in the sc and normal...

  14. Spin relaxation in nanowires by hyperfine coupling

    International Nuclear Information System (INIS)

    Echeverria-Arrondo, C.; Sherman, E.Ya.

    2012-01-01

    Hyperfine interactions establish limits on spin dynamics and relaxation rates in ensembles of semiconductor quantum dots. It is the confinement of electrons which determines nonzero hyperfine coupling and leads to the spin relaxation. As a result, in nanowires one would expect the vanishing of this effect due to extended electron states. However, even for relatively clean wires, disorder plays a crucial role and makes electron localization sufficient to cause spin relaxation on the time scale of the order of 10 ns. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Le Chatelier's principle with multiple relaxation channels

    Science.gov (United States)

    Gilmore, R.; Levine, R. D.

    1986-05-01

    Le Chatelier's principle is discussed within the constrained variational approach to thermodynamics. The formulation is general enough to encompass systems not in thermal (or chemical) equilibrium. Particular attention is given to systems with multiple constraints which can be relaxed. The moderation of the initial perturbation increases as additional constraints are removed. This result is studied in particular when the (coupled) relaxation channels have widely different time scales. A series of inequalities is derived which describes the successive moderation as each successive relaxation channel opens up. These inequalities are interpreted within the metric-geometry representation of thermodynamics.

  16. Universal Mechanism of Spin Relaxation in Solids

    Science.gov (United States)

    Chudnovsky, Eugene

    2006-03-01

    Conventional elastic theory ignores internal local twists and torques. Meantime, spin-lattice relaxation is inherently coupled with local elastic twists through conservation of the total angular momentum (spin + lattice). This coupling gives universal lower bound (free of fitting parameters) on the relaxation of the atomic or molecular spin in a solid [1] and on the relaxation of the electron spin in a quantum dot [2]. [1] E. M. Chudnovsky, D. A. Garanin, and R. Schilling, Phys. Rev. B 72, 094426 (2005). [2] C. Calero, E. M. Chudnovsky, and D. A. Garanin, Phys. Rev. Lett. 95, 166603 (2005).

  17. Collisional relaxation of electron tail distribution

    International Nuclear Information System (INIS)

    Yamagiwa, Mitsuru; Okamoto, Masao.

    1985-05-01

    Relaxation due to the Coulomb collisions of the electron velocity distribution function with a high energy tail is investigated in detail. In the course of the relaxation, a 'saddle' point can be created in velocity space owing to upsilon -3 dependence of the deflection rate and a positive slope or a 'dip' appears in the tail direction. The time evolution of the electron tail is studied analytically. A comparison is made with numerical results by using a Fokker-Planck code. Also discussed is the kinetic instability concerned with the positive slope during the relaxation. (author)

  18. Nuclear magnetic resonance relaxation in multiple sclerosis

    DEFF Research Database (Denmark)

    Larsson, H B; Barker, G J; MacKay, A

    1998-01-01

    OBJECTIVES: The theory of relaxation processes and their measurements are described. An overview is presented of the literature on relaxation time measurements in the normal and the developing brain, in experimental diseases in animals, and in patients with multiple sclerosis. RESULTS...... AND CONCLUSION: Relaxation time measurements provide insight into development of multiple sclerosis plaques, especially the occurrence of oedema, demyelination, and gliosis. There is also evidence that normal appearing white matter in patients with multiple sclerosis is affected. What is now needed are fast...

  19. Stress Relaxation in Entangled Polymer Melts

    DEFF Research Database (Denmark)

    Hou, Ji-Xuan; Svaneborg, Carsten; Everaers, Ralf

    2010-01-01

    We present an extensive set of simulation results for the stress relaxation in equilibrium and step-strained bead-spring polymer melts. The data allow us to explore the chain dynamics and the shear relaxation modulus, G(t), into the plateau regime for chains with Z=40 entanglements...... and into the terminal relaxation regime for Z=10. Using the known (Rouse) mobility of unentangled chains and the melt entanglement length determined via the primitive path analysis of the microscopic topological state of our systems, we have performed parameter-free tests of several different tube models. We find...

  20. Slow relaxation in weakly open rational polygons.

    Science.gov (United States)

    Kokshenev, Valery B; Vicentini, Eduardo

    2003-07-01

    The interplay between the regular (piecewise-linear) and irregular (vertex-angle) boundary effects in nonintegrable rational polygonal billiards (of m equal sides) is discussed. Decay dynamics in polygons (of perimeter P(m) and small opening Delta) is analyzed through the late-time survival probability S(m) approximately equal t(-delta). Two distinct slow relaxation channels are established. The primary universal channel exhibits relaxation of regular sliding orbits, with delta=1. The secondary channel is given by delta>1 and becomes open when m>P(m)/Delta. It originates from vertex order-disorder dual effects and is due to relaxation of chaoticlike excitations.

  1. Tetherless near-infrared control of brain activity in behaving animals using fully implantable upconversion microdevices.

    Science.gov (United States)

    Wang, Ying; Lin, Xudong; Chen, Xi; Chen, Xian; Xu, Zhen; Zhang, Wenchong; Liao, Qinghai; Duan, Xin; Wang, Xin; Liu, Ming; Wang, Feng; He, Jufang; Shi, Peng

    2017-10-01

    Many nanomaterials can be used as sensors or transducers in biomedical research and they form the essential components of transformative novel biotechnologies. In this study, we present an all-optical method for tetherless remote control of neural activity using fully implantable micro-devices based on upconversion technology. Upconversion nanoparticles (UCNPs) were used as transducers to convert near-infrared (NIR) energy to visible light in order to stimulate neurons expressing different opsin proteins. In our setup, UCNPs were packaged in a glass micro-optrode to form an implantable device with superb long-term biocompatibility. We showed that remotely applied NIR illumination is able to reliably trigger spiking activity in rat brains. In combination with a robotic laser projection system, the upconversion-based tetherless neural stimulation technique was implemented to modulate brain activity in various regions, including the striatum, ventral tegmental area, and visual cortex. Using this system, we were able to achieve behavioral conditioning in freely moving animals. Notably, our microscale device was at least one order of magnitude smaller in size (∼100 μm in diameter) and two orders of magnitude lighter in weight (less than 1 mg) than existing wireless optogenetic devices based on light-emitting diodes. This feature allows simultaneous implantation of multiple UCNP-optrodes to achieve modulation of brain function to control complex animal behavior. We believe that this technology not only represents a novel practical application of upconversion nanomaterials, but also opens up new possibilities for remote control of neural activity in the brains of behaving animals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Laying hens behave differently in artificially and naturally sourced ammoniated environments.

    Science.gov (United States)

    Pokharel, B B; Dos Santos, V M; Wood, D; Van Heyst, B; Harlander-Matauschek, A

    2017-12-01

    Laying hens are chronically exposed to high levels of ammonia (NH3), one of the most abundant aerial pollutants in poultry houses. Tests for aversion to NH3 in laying hens have used artificially sourced NH3/air mixtures (i.e., from a gas cylinder) showing that birds prefer fresh air to NH3. However, artificially sourced NH3/air mixtures may not accurately reflect barn air conditions, where manure emits a variety of gases. Herein, we investigated whether laying hens differentiate between artificially and naturally sourced NH3/air mixtures and how exposure to NH3 affects foraging and aversive behavior. A total of 20 laying hens was exposed to artificially sourced [A] (from an anhydrous NH3 cylinder) and naturally sourced [N] (from conspecific laying hen excreta) gas mixtures. Hens were exposed to A and N mixtures with NH3 concentrations of 25 and 45 ppm, as well as fresh air [FA]. During the experiment, all birds were exposed to each treatment 3 times using a custom-built polycarbonate chamber, containing a foraging area (containing raisins, mealworms, and feed mix) and a gas delivery system. All testing sessions were video recorded, analyzed with INTERACT® software, and subjected to a GLIMMIX procedure in SAS. Our results showed that the laying hens spent less time foraging overall (P hens were more likely to forage for a longer time (with fewer interruptions) in N than in A treatments (P hens also reacted with greater aversion towards treatment A compared to treatment N (P hens of our study preferred fresh to ammoniated air and that they behaved differently in artificially and naturally sourced NH3/air mixtures, possibly due to the presence of familiar stimuli from the excreta. These findings have implications for new developments in methodological approaches for behavioral testing and for recommendations regarding NH3 levels inside poultry barns. © 2017 Poultry Science Association Inc.

  3. Head-mounted LED for optogenetic experiments of freely-behaving animal

    Science.gov (United States)

    Kwon, Ki Yong; Gnade, Andrew G.; Rush, Alexander D.; Patten, Craig D.

    2016-03-01

    Recent developments in optogenetics have demonstrated the ability to target specific types of neurons with sub-millisecond temporal precision via direct optical stimulation of genetically modified neurons in the brain. In most applications, the beam of a laser is coupled to an optical fiber, which guides and delivers the optical power to the region of interest. Light emitting diodes (LEDs) are an alternative light source for optogenetics and they provide many advantages over a laser based system including cost, size, illumination stability, and fast modulation. Their compact size and low power consumption make LEDs suitable light sources for a wireless optogenetic stimulation system. However, the coupling efficiency of an LED's output light into an optical fiber is lower than a laser due to its noncollimated output light. In typical chronic optogenetic experiment, the output of the light source is transmitted to the brain through a patch cable and a fiber stub implant, and this configuration requires two fiber-to-fiber couplings. Attenuation within the patch cable is potential source of optical power loss. In this study, we report and characterize a recently developed light delivery method for freely-behaving animal experiments. We have developed a head-mounted light source that maximizes the coupling efficiency of an LED light source by eliminating the need for a fiber optic cable. This miniaturized LED is designed to couple directly to the fiber stub implant. Depending on the desired optical power output, the head-mounted LED can be controlled by either a tethered (high power) or battery-powered wireless (moderate power) controller. In the tethered system, the LED is controlled through 40 gauge micro coaxial cable which is thinner, more flexible, and more durable than a fiber optic cable. The battery-powered wireless system uses either infrared or radio frequency transmission to achieve real-time control. Optical, electrical, mechanical, and thermal

  4. Usefulness of muscle denervation as an MRI sign of peripheral nerve pathology

    International Nuclear Information System (INIS)

    Lisle, D. A.; Johnstone, S. A.

    2007-01-01

    Full text: Peripheral nerve disorders may be classified into compressive or entrapment neuropathies and non-compressive neuropathies. Muscle denervation recognized on MRI may be a useful sign in the diagnosis of peripheral nerve disorders. Acute or subacute denervation results in prolonged T 2 relaxation time, producing increased signal in skeletal muscle on short tau inversion-recovery and fat-suppressed T 2 -weighted images. Chronic denervation produces fatty atrophy of skeletal muscles, resulting in increased muscle signal on T 1 -weighted images. This review will outline and illustrate the various ways that muscle denervation as seen on MRI may assist in the diagnosis and localization of peripheral nerve disorders

  5. Mesenteric artery contraction and relaxation studies using automated wire myography.

    Science.gov (United States)

    Bridges, Lakeesha E; Williams, Cicely L; Pointer, Mildred A; Awumey, Emmanuel M

    2011-09-22

    Proximal resistance vessels, such as the mesenteric arteries, contribute substantially to the peripheral resistance. These small vessels of between 100-400 μm in diameter function primarily in directing blood flow to various organs according to the overall requirements of the body. The rat mesenteric artery has a diameter greater than 100 μm. The myography technique, first described by Mulvay and Halpern(1), was based on the method proposed by Bevan and Osher(2). The technique provides information about small vessels under isometric conditions, where substantial shortening of the muscle preparation is prevented. Since force production and sensitivity of vessels to different agonists is dependent on the extent of stretch, according to active tension-length relation, it is essential to conduct contraction studies under isometric conditions to prevent compliance of the mounting wires. Stainless steel wires are preferred to tungsten wires because of oxidation of the latter, which affects recorded responses(3).The technique allows for the comparison of agonist-induced contractions of mounted vessels to obtain evidence for normal function of vascular smooth muscle cell receptors. We have shown in several studies that isolated mesenteric arteries that are contracted with phenylyephrine relax upon addition of cumulative concentrations of extracellular calcium (Ca(2+)(e;)). The findings led us to conclude that perivascular sensory nerves, which express the G protein-coupled Ca(2+)-sensing receptor (CaR), mediate this vasorelaxation response. Using an automated wire myography method, we show here that mesenteric arteries from Wistar, Dahl salt-sensitive(DS) and Dahl salt-resistant (DR) rats respond differently to Ca(2+)(e;). Tissues from Wistar rats showed higher Ca(2+)-sensitivity compared to those from DR and DS. Reduced CaR expression in mesenteric arteries from DS rats correlates with reduced Ca(2+)(e;)-induced relaxation of isolated, pre-contracted arteries. The data

  6. Relaxation processes during amorphous metal alloys heating

    International Nuclear Information System (INIS)

    Malinochka, E.Ya.; Durachenko, A.M.; Borisov, V.T.

    1982-01-01

    Behaviour of Te+15 at.%Ge and Fe+13 at.%P+7 at.%C amorphous metal alloys during heating has been studied using the method of differential scanning calorimetry (DSC) as the most convenient one for determination of the value of heat effects, activation energies, temperature ranges of relaxation processes. Thermal effects corresponding to high-temperature relaxation processes taking place during amorphous metal alloys (AMA) heating are detected. The change of ratio of relaxation peaks values on DSC curves as a result of AMA heat treatment can be explained by the presence of a number of levels of inner energy in amorphous system, separated with potential barriers, the heights of which correspond to certain activation energies of relaxation processes

  7. The relaxation of plasmas with dust particles

    International Nuclear Information System (INIS)

    Chutov, Yu.I.; Kravchenko, A.Yu.; Schram, P.P.J.M.

    1997-01-01

    Various parameters of relaxing plasmas with dust particles including the electron and ion energy distributions function are numerically simulated at various parameters of the dust particles using the PIC method and taking into account the dynamics of the dust particle charge without the assumption about the equilibrium of electrons and ions. Coulomb collisions are taken into account in the framework of the method of stochastic differential equations. The relaxation of bounded plasma clouds expanding into a vacuum as well as the relaxation of a uniform plasma, in which dust particles appear at some initial time, are investigated. The obtained results show that the relaxation of plasmas can be accompanied by a deviation of the ion distribution function from equilibrium as well as a change of the mean energy of electrons and ions because of the dependence of the collection of electrons and ions by dust particles on their energy. (author)

  8. Multiscale dipole relaxation in dielectric materials

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt

    2016-01-01

    Dipole relaxation from thermally induced perturbations is investigated on different length scales for dielectric materials. From the continuum dynamical equations for the polarisation, expressions for the transverse and longitudinal dipole autocorrelation functions are derived in the limit where ...

  9. Generalized approach to non-exponential relaxation

    Indian Academy of Sciences (India)

    Non-exponential relaxation is a universal feature of systems as diverse as glasses, spin ... which changes from a simple exponential to a stretched exponential and a power law by increasing the constraints in the system. ... Current Issue

  10. Oxygen-17 relaxation in aqueous agarose gels

    International Nuclear Information System (INIS)

    Ablett, S.; Lillford, P.J.

    1977-01-01

    Nuclear magnetic relaxation of oxygen-17 in H 2 17 O enriched agarose gels shows that existing explanations of water behaviour are oversimplified. Satisfactory models must include at least three proton phases, two of which involve water molecules. (Auth.)

  11. Muscle activity pattern dependent pain development and alleviation.

    Science.gov (United States)

    Sjøgaard, Gisela; Søgaard, Karen

    2014-12-01

    Muscle activity is for decades considered to provide health benefits irrespectively of the muscle activity pattern performed and whether it is during e.g. sports, transportation, or occupational work tasks. Accordingly, the international recommendations for public health-promoting physical activity do not distinguish between occupational and leisure time physical activity. However, in this body of literature, attention has not been paid to the extensive documentation on occupational physical activity imposing a risk of impairment of health - in particular musculoskeletal health in terms of muscle pain. Focusing on muscle activity patterns and musculoskeletal health it is pertinent to elucidate the more specific aspects regarding exposure profiles and body regional pain. Static sustained muscle contraction for prolonged periods often occurs in the neck/shoulder area during occupational tasks and may underlie muscle pain development in spite of rather low relative muscle load. Causal mechanisms include a stereotype recruitment of low threshold motor units (activating type 1 muscle fibers) characterized by a lack of temporal as well as spatial variation in recruitment. In contrast during physical activities at leisure and sport the motor recruitment patterns are more dynamic including regularly relatively high muscle forces - also activating type 2 muscles fibers - as well as periods of full relaxation even of the type 1 muscle fibers. Such activity is unrelated to muscle pain development if adequate recovery is granted. However, delayed muscle soreness may develop following intensive eccentric muscle activity (e.g. down-hill skiing) with peak pain levels in thigh muscles 1-2 days after the exercise bout and a total recovery within 1 week. This acute pain profile is in contrast to the chronic muscle pain profile related to repetitive monotonous work tasks. The painful muscles show adverse functional, morphological, hormonal, as well as metabolic characteristics. Of

  12. Myofilament calcium sensitivity: Role in regulation of in vivo cardiac contraction and relaxation

    Directory of Open Access Journals (Sweden)

    Jae-Hoon Chung

    2016-12-01

    Full Text Available Myofilament calcium sensitivity is an often-used indicator of cardiac muscle function, often assessed in disease states such as hypertrophic cardiomyopathy (HCM and dilated cardiomyopathy (DCM. While calcium sensitivity measurement provides important insights into the mechanical force-generating capability of a muscle at steady-state, the dynamic behavior of the muscle cannot be sufficiently assessed with a force-pCa curve alone. The dissociation constant (Kd of the force-pCa curve depends on the ratio of the apparent on-rate (kon and apparent off-rate (koff of calcium on TnC and as a stand-alone parameter cannot provide an accurate depiction of the dynamic contraction and relaxation behavior without the additional quantification of kon or koff, or actually measuring dynamic twitch kinetics in an intact muscle. In this review, we examine the effect of length, frequency, and beta-adrenergic stimulation on myofilament calcium sensitivity and dynamic contraction, the effect of membrane permeabilization on calcium sensitivity, and the dynamic consequences of various myofilament protein mutations with potential implications in contractile and relaxation behavior.

  13. Relaxation and hypnosis in pediatric dental patients.

    Science.gov (United States)

    Peretz, B

    1996-01-01

    Relaxation and hypnosis are methods which, may solve the problem of extreme dental anxiety, when all other methods, behavioral or pharmacological may not be used. A simple definition of hypnosis is suggestion and repetition. Suggestion is the process whereby an individual accepts a proposition put to him by another, without having the slightest logical reason for doing so. Relaxation is one method of inducing hypnosis. A case of using hypnosis on an 11-year-old boy is described.

  14. Ghost lines in Moessbauer relaxation spectra

    International Nuclear Information System (INIS)

    Price, D.C.

    1985-01-01

    The appearance in Moessbauer relaxation spectra of 'ghost' lines, which are narrow lines that do not correspond to transitions between real hyperfine energy levels of the resonant system, is examined. It is shown that in many cases of interest, the appearance of these 'ghost' lines can be interpreted in terms of the relaxational averaging of one or more of the static interactions of the ion. (orig.)

  15. Dynamics of helicity transport and Taylor relaxation

    International Nuclear Information System (INIS)

    Diamond, P.H.; Malkov, M.

    2003-01-01

    A simple model of the dynamics of Taylor relaxation is derived using symmetry principles alone. No statistical closure approximations are invoked or detailed plasma model properties assumed. Notably, the model predicts several classes of nondiffusive helicity transport phenomena, including traveling nonlinear waves and superdiffusive turbulent pulses. A universal expression for the scaling of the effective magnetic Reynolds number of a system undergoing Taylor relaxation is derived. Some basic properties of intermittency in helicity transport are examined

  16. Regularities of intermediate adsorption complex relaxation

    International Nuclear Information System (INIS)

    Manukova, L.A.

    1982-01-01

    The experimental data, characterizing the regularities of intermediate adsorption complex relaxation in the polycrystalline Mo-N 2 system at 77 K are given. The method of molecular beam has been used in the investigation. The analytical expressions of change regularity in the relaxation process of full and specific rates - of transition from intermediate state into ''non-reversible'', of desorption into the gas phase and accumUlation of the particles in the intermediate state are obtained

  17. Relaxation of synchronization on complex networks.

    Science.gov (United States)

    Son, Seung-Woo; Jeong, Hawoong; Hong, Hyunsuk

    2008-07-01

    We study collective synchronization in a large number of coupled oscillators on various complex networks. In particular, we focus on the relaxation dynamics of the synchronization, which is important from the viewpoint of information transfer or the dynamics of system recovery from a perturbation. We measure the relaxation time tau that is required to establish global synchronization by varying the structural properties of the networks. It is found that the relaxation time in a strong-coupling regime (K>Kc) logarithmically increases with network size N , which is attributed to the initial random phase fluctuation given by O(N-1/2) . After elimination of the initial-phase fluctuation, the relaxation time is found to be independent of the system size; this implies that the local interaction that depends on the structural connectivity is irrelevant in the relaxation dynamics of the synchronization in the strong-coupling regime. The relaxation dynamics is analytically derived in a form independent of the system size, and it exhibits good consistency with numerical simulations. As an application, we also explore the recovery dynamics of the oscillators when perturbations enter the system.

  18. Stress relaxation in viscous soft spheres.

    Science.gov (United States)

    Boschan, Julia; Vasudevan, Siddarth A; Boukany, Pouyan E; Somfai, Ellák; Tighe, Brian P

    2017-10-04

    We report the results of molecular dynamics simulations of stress relaxation tests in athermal viscous soft sphere packings close to their unjamming transition. By systematically and simultaneously varying both the amplitude of the applied strain step and the pressure of the initial condition, we access both linear and nonlinear response regimes and control the distance to jamming. Stress relaxation in viscoelastic solids is characterized by a relaxation time τ* that separates short time scales, where viscous loss is substantial, from long time scales, where elastic storage dominates and the response is essentially quasistatic. We identify two distinct plateaus in the strain dependence of the relaxation time, one each in the linear and nonlinear regimes. The height of both plateaus scales as an inverse power law with the distance to jamming. By probing the time evolution of particle velocities during relaxation, we further identify a correlation between mechanical relaxation in the bulk and the degree of non-affinity in the particle velocities on the micro scale.

  19. Relaxation strain measurements in cellular dislocation structures

    International Nuclear Information System (INIS)

    Tsai, C.Y.; Quesnel, D.J.

    1984-01-01

    The conventional picture of what happens during a stress relaxation usually involves imagining the response of a single dislocation to a steadily decreasing stress. The velocity of this dislocation decreases with decreasing stress in such a way that we can measure the stress dependence of the dislocation velocity. Analysis of the data from a different viewpoint enables us to calculate the apparent activation volume for the motion of the dislocation under the assumption of thermally activated glie. Conventional thinking about stress relaxation, however, does not consider the eventual fate of this dislocation. If the stress relaxes to a low enough level, it is clear that the dislocation must stop. This is consistent with the idea that we can determine the stress dependence of the dislocation velocity from relaxation data only for those cases where the dislocation's velocity is allowed to approach zero asymptotically, in short, for those cases where the dislocation never stops. This conflict poses a dilemma for the experimentalist. In real crystals, however, obstacles impede the dislocation's progress so that those dislocations which are stopped at a given stress will probably never resume motion under the influence of the steadily declining stress present during relaxation. Thus one could envision stress relaxation as a process of exhaustion of mobile dislocations, rather than a process of decreasing dislocation velocity. Clearly both points of view have merit and in reality both mechanisms contribute to the phenomena

  20. Temperature Scanning Stress Relaxation of an Autonomous Self-Healing Elastomer Containing Non-Covalent Reversible Network Junctions

    Directory of Open Access Journals (Sweden)

    Amit Das

    2018-01-01

    Full Text Available In this work, we report about the mechanical relaxation characteristics of an intrinsically self-healable imidazole modified commercial rubber. This kind of self-healing rubber was prepared by melt mixing of 1-butyl imidazole with bromo-butyl rubber (bromine modified isoprene-isobutylene copolymer, BIIR. By this melt mixing process, the reactive allylic bromine of bromo-butyl rubber was converted into imidazole bromide salt. The resulting development of an ionic character to the polymer backbone leads to an ionic association of the groups which ultimately results to the formation of a network structure of the rubber chains. The modified BIIR thus behaves like a robust crosslinked rubber and shows unusual self-healing properties. The non-covalent reversible network has been studied in detail with respect to stress relaxation experiments, scanning electron microscopic and X-ray scattering.

  1. The effects of progressive muscular relaxation as a nursing procedure used for those who suffer from stress due to multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Paolla Gabrielle Nascimento Novais

    Full Text Available ABSTRACT Objective: to evaluate the effect of progressive muscle relaxation as a nursing procedure on the levels of stress for sufferers of multiple sclerosis. Method: random clinical trials conducted at the Neurology outpatients unit at a University Hospital. The sample consisted of 40 patients who were being monitored as outpatients (20 in a control group and 20 in an experimental group. The Progressive Muscle Relaxation technique was used. The control variables were collected through interviews that were recorded on forms and on the Perceived Stress Scale that we used. Five meetings were held every fortnight covering a period of eight weeks. The experimental group was advised to carry out daily progressive muscle relaxation activities. After eight weeks of these activities, they were evaluated again to measure their levels of stress. In order to analyze the data used, the software package Statistics for Social Sciences version 19.0 was used. Results: the application of the t test showed a significant reduction in the Perceived Stress Scale scores in the experimental group (p<0.001, which in turn proved that there was a reduction in the levels of stress after the application of the relaxation practic-es. Conclusion: the progressive muscle relaxation activities contributed to the reduction in stress levels for multiple sclerosis suffers and thus can be used in nursing for patients. Clinical Trials Identifier: NCT 02673827.

  2. Extraocular muscle function testing

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003397.htm Extraocular muscle function testing To use the sharing features on this page, please enable JavaScript. Extraocular muscle function testing examines the function of the eye muscles. ...

  3. Beta2-adrenoceptor-mediated tracheal relaxation induced by higenamine from Nandina domestica Thunberg.

    Science.gov (United States)

    Tsukiyama, Muneo; Ueki, Takuro; Yasuda, Yoichi; Kikuchi, Hiroko; Akaishi, Tatsuhiro; Okumura, Hidenobu; Abe, Kazuho

    2009-10-01

    The fruit of Nandina domestica Thunberg (ND, Berberidaceae) has been used to improve cough and breathing difficulties in Japan for many years, but very little is known about the constituent of ND responsible for this effect. We have recently reported that the crude extract from ND (NDE) inhibits histamine- and serotonin-induced contraction of isolated guinea pig trachea, and the inhibitory activity was not explained by nantenine, a well-known alkaloid isolated from ND. To explore other constituent(s) of NDE with tracheal smooth muscle relaxant activity, we fractionated NDE and assessed the pharmacological effects of the fractions using isolated guinea pig tracheal ring preparations. NDE was introduced into a polyaromatic absorbent resin column and stepwise eluted to yield five fractions, among which only the 40 % methanol fraction was active in relaxing tracheal smooth muscle precontracted with histamine. Further separation of the 40 % methanol fraction with high-performance liquid chromatography yielded multiple subfractions, one of which was remarkably active in relaxing histamine-precontracted trachea. Chemical analysis with a time-of-flight mass spectrometer and nuclear magnetic resonance spectrometer identified the constituent of the most active subfraction as higenamine, a benzyltetrahydroisoquinoline alkaloid. The potency and efficacy of the active constituent from NDE in relaxing trachea were almost equivalent to synthetic higenamine. In addition, the effect of the active constituent from NDE was competitively inhibited by the selective beta (2)-adrenoceptor antagonist ICI 118,551. These results indicate that the major constituent responsible for the effect of NDE is higenamine, which probably causes the tracheal relaxation through stimulation of beta (2) adrenoceptors. Georg Thieme Verlag KG Stuttgart-New York.

  4. Functional Echomyography: thickness, ecogenicity, contraction and perfusion of the LMN denervated human muscle before and during h-bFES

    Directory of Open Access Journals (Sweden)

    Riccardo Zanato

    2010-03-01

    Full Text Available Permanent denervated muscles were evaluated by ultrasound to monitor changes in morphology, thickness, contraction-relaxation kinetics and perfusion due to the electrical stimulation program of the Rise2-Italy project. In a case of monolateral lesion, morphology and ultrasonographic structure of the denervated muscles changed during the period of stimulation from a pattern typical of complete denervation-induced muscle atrophy to a pattern which might be considered “normal” when detected in an old patient. Thickness improved significantly more in the middle third of the denervated muscle, reaching the same value as the contralateral innervated muscle. Contraction-relaxation kinetics, measured by recording the muscle movements during electrical stimulation, showed an abnormal behavior of the chronically denervated muscle during the relaxation phase, which resulted to be significantly longer than in normal muscle. The long-term denervated muscles analyzed with Echo Doppler showed at rest a low resistance arterial flow that became pulsed during and after electrical stimulation. As expected, the ultra sound measured electrical stimulation-induced hyperemia lasted longer than the stimulation period. The higher than normal energy of the delivered electrical stimuli of the Vienna home-based Functional Electrical Stimulation strategy (h-b FES demonstrate that the explored muscles were still almost completely denervated during the one-year of training. In conclusion, this pilot study confirms the usefulness of Functional Echomyography in the follow-up and the positive effects of h-b FES of denervated muscles.

  5. Regulation and dysregulation of esophageal peristalsis by the integrated function of circular and longitudinal muscle layers in health and disease.

    Science.gov (United States)

    Mittal, Ravinder K

    2016-09-01

    Muscularis propria throughout the entire gastrointestinal tract including the esophagus is comprised of circular and longitudinal muscle layers. Based on the studies conducted in the colon and the small intestine, for more than a century, it has been debated whether the two muscle layers contract synchronously or reciprocally during the ascending contraction and descending relaxation of the peristaltic reflex. Recent studies in the esophagus and colon prove that the two muscle layers indeed contract and relax together in almost perfect synchrony during ascending contraction and descending relaxation of the peristaltic reflex, respectively. Studies in patients with various types of esophageal motor disorders reveal temporal disassociation between the circular and longitudinal muscle layers. We suggest that the discoordination between the two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain. Certain pathologies may selectively target one and not the other muscle layer, e.g., in eosinophilic esophagitis there is a selective dysfunction of the longitudinal muscle layer. In achalasia esophagus, swallows are accompanied by the strong contraction of the longitudinal muscle without circular muscle contraction. The possibility that the discoordination between two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain are discussed. The purpose of this review is to summarize the regulation and dysregulation of peristalsis by the coordinated and discoordinated function of circular and longitudinal muscle layers in health and diseased states.

  6. Muscle glycogen and cell function - Location, location, location

    DEFF Research Database (Denmark)

    Ørtenblad, N; Nielsen, Joachim

    2015-01-01

    The importance of glycogen, as a fuel during exercise, is a fundamental concept in exercise physiology. The use of electron microscopy has revealed that glycogen is not evenly distributed in skeletal muscle fibers, but rather localized in distinct pools. In this review, we present the available...... evidence regarding the subcellular localization of glycogen in skeletal muscle and discuss this from the perspective of skeletal muscle fiber function. The distribution of glycogen in the defined pools within the skeletal muscle varies depending on exercise intensity, fiber phenotype, training status......, and immobilization. Furthermore, these defined pools may serve specific functions in the cell. Specifically, reduced levels of these pools of glycogen are associated with reduced SR Ca(2+) release, muscle relaxation rate, and membrane excitability. Collectively, the available literature strongly demonstrates...

  7. Bioelectrical activity of the pelvic floor muscles after 6-week biofeedback training in nulliparous continent women.

    Science.gov (United States)

    Chmielewska, Daria; Stania, Magdalena; Smykla, Agnieszka; Kwaśna, Krystyna; Błaszczak, Edward; Sobota, Grzegorz; Skrzypulec-Plinta, Violetta

    2016-01-01

    The aim of the study was to evaluate the effects of a 6-week sEMG-biofeedback-assisted pelvic floor muscle training program on pelvic floor muscle activity in young continent women. Pelvic floor muscle activity was recorded using a vaginal probe during five experimental trials. Biofeedback training was continued for 6 weeks, 3 times a week. Muscle strenghtening and endurance exercises were performed alternately. SEMG (surface electromyography) measurements were recorded on four different occasions: before training started, after the third week of training, after the sixth week of training, and one month after training ended. A 6-week sEMG-biofeedback-assisted pelvic floor muscle training program significantly decreased the resting activity of the pelvic floor muscles in supine lying and standing. The ability to relax the pelvic floor muscles after a sustained 60-second contraction improved significantly after the 6-week training in both positions. SEMG-biofeedback training program did not seem to affect the activity of the pelvic floor muscles or muscle fatigue during voluntary pelvic floor muscle contractions. SEMG-biofeedback-assisted pelvic floor muscle training might be recommended for physiotherapists to improve the effectiveness of their relaxation techniques.

  8. Cancer cachexia decreases specific force and accelerates fatigue in limb muscle

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, B. M. [1225 Center Drive, HPNP Building Room 1142, Department of Physical Therapy, University of Florida, Gainesville, FL 32610 (United States); Frye, G. S.; Ahn, B.; Ferreira, L. F. [1864 Stadium Road, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL 32610 (United States); Judge, A.R., E-mail: arjudge@phhp.ufl.edu [1225 Center Drive, HPNP Building Room 1142, Department of Physical Therapy, University of Florida, Gainesville, FL 32610 (United States)

    2013-06-07

    Highlights: •C-26 cancer cachexia causes a significant decrease in limb muscle absolute force. •C-26 cancer cachexia causes a significant decrease in limb muscle specific force. •C-26 cancer cachexia decreases fatigue resistance in the soleus muscle. •C-26 cancer cachexia prolongs time to peak twitch tension in limb muscle. •C-26 cancer cachexia prolongs one half twitch relaxation time in limb muscle. -- Abstract: Cancer cachexia is a complex metabolic syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia have recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. However, more recently, we provided evidence that during severe cancer cachexia muscle weakness in the diaphragm muscle cannot be entirely accounted for by the muscle atrophy. This indicates that muscle weakness is not just a consequence of muscle atrophy but that there is also significant contractile dysfunction. The current study aimed to determine whether contractile dysfunction is also present in limb muscles during severe Colon-26 (C26) carcinoma cachexia by studying the glycolytic extensor digitorum longus (EDL) muscle and the oxidative soleus muscle, which has an activity pattern that more closely resembles the diaphragm. Severe C-26 cancer cachexia caused significant muscle fiber atrophy and a reduction in maximum absolute force in both the EDL and soleus muscles. However, normalization to muscle cross sectional area further demonstrated a 13% decrease in maximum isometric specific force in the EDL and an even greater decrease (17%) in maximum isometric specific force in the soleus. Time to peak tension and half relaxation time were also significantly slowed in both the EDL and the solei from C-26 mice compared to controls. Since, in addition to postural control, the oxidative

  9. Cancer cachexia decreases specific force and accelerates fatigue in limb muscle

    International Nuclear Information System (INIS)

    Roberts, B.M.; Frye, G.S.; Ahn, B.; Ferreira, L.F.; Judge, A.R.

    2013-01-01

    Highlights: •C-26 cancer cachexia causes a significant decrease in limb muscle absolute force. •C-26 cancer cachexia causes a significant decrease in limb muscle specific force. •C-26 cancer cachexia decreases fatigue resistance in the soleus muscle. •C-26 cancer cachexia prolongs time to peak twitch tension in limb muscle. •C-26 cancer cachexia prolongs one half twitch relaxation time in limb muscle. -- Abstract: Cancer cachexia is a complex metabolic syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia have recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. However, more recently, we provided evidence that during severe cancer cachexia muscle weakness in the diaphragm muscle cannot be entirely accounted for by the muscle atrophy. This indicates that muscle weakness is not just a consequence of muscle atrophy but that there is also significant contractile dysfunction. The current study aimed to determine whether contractile dysfunction is also present in limb muscles during severe Colon-26 (C26) carcinoma cachexia by studying the glycolytic extensor digitorum longus (EDL) muscle and the oxidative soleus muscle, which has an activity pattern that more closely resembles the diaphragm. Severe C-26 cancer cachexia caused significant muscle fiber atrophy and a reduction in maximum absolute force in both the EDL and soleus muscles. However, normalization to muscle cross sectional area further demonstrated a 13% decrease in maximum isometric specific force in the EDL and an even greater decrease (17%) in maximum isometric specific force in the soleus. Time to peak tension and half relaxation time were also significantly slowed in both the EDL and the solei from C-26 mice compared to controls. Since, in addition to postural control, the oxidative

  10. Use of relaxation skills in differentially skilled athletes.

    OpenAIRE

    Kudlackova, K.; Eccles, D. W.; Dieffenbach, K.

    2013-01-01

    Objectives: To examine the use of relaxation skills by differentially skilled athletes in relation to the deliberate practice framework. Design: Differentially skilled athletes completed a survey about their use of relaxation skills. Method: 150 athletes representing three skill levels (recreational, college, and professional) completed the deliberate relaxation for sport survey, which assessed relaxation on three deliberate practice dimensions (relevancy, concentration, and ...

  11. The use of (double) relaxation oscillation SQUIDs as a sensor

    NARCIS (Netherlands)

    van Duuren, M.J.; Brons, G.C.S.; Kattouw, H.; Flokstra, Jakob; Rogalla, Horst

    1997-01-01

    Relaxation Oscillation SQUIDs (ROSs) and Double Relaxation Oscillation SQUIDs (DROSs) are based on relaxation oscillations that are induced in hysteretic dc SQUIDs by an external L-R shunt. The relaxation frequency of a ROS varies with the applied flux Φ, whereas the output of a DROS is a dc

  12. Entire mesodermal mantle behaves as Spemann's organizer in dorsoanterior enhanced Xenopus laevis embryos

    International Nuclear Information System (INIS)

    Kao, K.R.; Elinson, R.P.

    1988-01-01

    The body plan of Xenopus laevis can be respecified by briefly exposing early cleavage stage embryos to lithium. Such embryos develop exaggerated dorsoanterior structures such as a radial eye and cement gland. In this paper, we demonstrate that the enhanced dorsoanterior phenotype results from an overcommitment of mesoderm to dorsoanterior mesoderm. Histological and immunohistochemical observations reveal that the embryos have a greatly enlarged notochord with very little muscle tissue. In addition, they develop a radial, beating heart, suggesting that lithium also specifies anterior mesoderm and pharyngeal endoderm. Randomly oriented diametrically opposed marginal zone grafts from lithium-treated embryos, when transplanted into ultraviolet (uv)-irradiated axis-deficient hosts, rescue dorsal axial structures. These transplantation experiments demonstrate that the entire marginal zone of the early gastrula consists of presumptive dorsal mesoderm. Vital dye marking experiments also indicate that the entire marginal zone maps to the prominent proboscis that is composed of chordamesoderm and represents the long axis of the embryo. These results suggest that lithium respecifies the mesoderm of Xenopus laevis embryos so that it differentiates into the Spemann organizer. We suggest that the origin of the dorsoanterior enhanced phenotypes generated by lithium and the dorsoanterior deficient phenotypes generated by uv irradiation are due to relative quantities of organizer. Our evidence demonstrates the existence of a continuum of body plan phenotypes based on this premise

  13. Extraction of motor activity from the cervical spinal cord of behaving rats

    Science.gov (United States)

    Prasad, Abhishek; Sahin, Mesut

    2006-12-01

    Injury at the cervical region of the spinal cord results in the loss of the skeletal muscle control from below the shoulders and hence causes quadriplegia. The brain-computer interface technique is one way of generating a substitute for the lost command signals in these severely paralyzed individuals using the neural signals from the brain. In this study, we are investigating the feasibility of an alternative method where the volitional signals are extracted from the cervical spinal cord above the point of injury. A microelectrode array assembly was implanted chronically at the C5-C6 level of the spinal cord in rats. Neural recordings were made during the face cleaning behavior with forelimbs as this task involves cyclic forelimb movements and does not require any training. The correlation between the volitional motor signals and the elbow movements was studied. Linear regression technique was used to reconstruct the arm movement from the rectified-integrated version of the principal neural components. The results of this study demonstrate the feasibility of extracting the motor signals from the cervical spinal cord and using them for reconstruction of the elbow movements.

  14. A novel vibrotactile system for stimulating the glabrous skin of awake freely behaving rats during operant conditioning.

    Science.gov (United States)

    Devecioğlu, İsmail; Güçlü, Burak

    2015-03-15

    Rat skin is innervated by mechanoreceptive fibers similar to those in other mammals. Tactile experiments with behaving rats mostly focus on the vibrissal system which does not exist in humans. The aim of this study was to design and implement a novel vibrotactile system to stimulate the glabrous skin of behaving rats during operant conditioning. A computer-controlled vibrotactile system was developed for various tasks in which the volar surface of unrestrained rats' fore- and hindpaws was stimulated in an operant chamber. The operant chamber was built from off-the-shelf components. A highly accurate electrodynamic shaker with a novel multi-probe design was used for generating mechanical displacements. Twenty-five rats were trained for four sequential tasks: (A) middle-lever (trial start signal) press, (B) side-lever press with an associated visual cue, (C) similar to (B) with the addition of an auditory/tactile stimulus, (D) auditory/tactile detection (yes/no) task. Out of 9 rats which could complete the tactile version of this training schedule, 5 had over 70% accuracy in the tactile version of the detection task. Unlike actuators for stimulating whiskers, this system does not require a particular head/body alignment and can be used with freely behaving animals. The vibrotactile system was found to be effective for conditioning freely behaving rats based on stimuli applied on the glabrous skin. However, detection accuracies were lower compared to those in tasks involving whisker stimulation reported previously, probably due to differences in cortical processing. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Phase separation, clustering, and fractal characteristics in glass: A magic-angle-spinning NMR spin-lattice relaxation study

    Science.gov (United States)

    Sen, S.; Stebbins, J. F.

    1994-07-01

    A comparative study of the 29Si spin-lattice relaxation behavior (induced by trace amounts of paramagnetic dopants in the glass) in phase-separated Li2Si4O9 and monophasic Li2Si2O5 and Na2Si2O5 glasses has been made in order to understand the nature of clustering and the resulting intermediate-range ordering. Optically clear tetrasilicate and disilicate glasses were prepared with 500 to 2000 ppm of Gd2O3, a paramagnetic dopant. The constituent structural units (Q3 and Q4 species) in all tetrasilicate glasses show strong differential relaxation following a power-law behavior. This is due to preferential partitioning of Gd3+ into the lower silica (Q3-rich) regions of these glasses, indicating the presence of Q species clusters too small to produce optical opalescence (a few nm to perhaps tens of nm). Preliminary results on 6Li spin-lattice relaxation in these glasses support this hypothesis. Differential relaxation becomes more pronounced on annealing due to growth of such clusters. No such differential relaxation was observed in the monophase disilicate glasses. For spin-lattice relaxation induced by direct dipolar coupling to paramagnetic ions, the recovery of magnetization is proportional to time as M(t)~tα where α is a function of the dimensionality D of mass distribution of the constituent Q species around the Gd3+ paramagnetic centers in the glass. For tetrasilicate glasses D~=2.62+/-0.22 and the system behaves as a mass fractal up to a length scale of 2 to 3 nm. D is thus equal to, within error, the theoretical value of 2.6 for an infinite percolation cluster of one type of Q species in another. For disilicate glasses, D~=3.06+/-0.18 which indicates a three-dimensional (and thus nonfractal) mass distribution of the constituent Q species over the same length scale.

  16. A COMPARATIVE STUDY ON EFFECTIVENESS OF STATIC STRETCH AND HOLD RELAX TECHNIQUES OVER HAMSTRING FLEXIBILITY

    Directory of Open Access Journals (Sweden)

    N. Vamsidhar

    2014-12-01

    Full Text Available Background: Flexibility is important in prevention of injury, muscular and postural imbalance more over the Hamstring flexibility has a lion share in sports performances and preventing DOMS. Stretching procedures increases the ROM by embarking on biomechanics and Neurologic and molecular mechanics. Hamstrings, the two joint muscle plays a crucial role in two joints integrity and also spine as they are in closed kinematic chain. The hamstring muscles represent the primary flexors of Knee. Hamstrings tightness results in Limits Knee extension when hip is flexed, Posterior Pelvic tilt, and flatten the lumbar spine. Methods: The subjects selected randomly and divided into two groups (Experimental group and control group.30 samples in One group applied with Static Stretch once a day for 3 repetitions 5 days a week for six weeks and 30 samples in other group applied with Hold relax technique once a day for 4 repetitions 5 days a week for six weeks. The knee joint range of motion was measured at the end of every week with Universal goniometer. Results: By comparing the means of Group – I, given Static Stretch and Group – II, given Hold relax Technique for six weeks implied that there is improvement of flexibility in Group – II and the ‘P’ value < 0.01 shows the difference is highly significant. Conclusion: This study concludes that the hold relax Technique method has proved to be better technique then the static stretch for improving hamstring flexibility.

  17. Relaxant effects of a hydroalcoholic extract of Ruta graveolens on isolated rat tracheal rings

    Directory of Open Access Journals (Sweden)

    Luis Águila

    2015-01-01

    Full Text Available BACKGROUND: Ruta graveolens L. (R. graveolens is a medicinal plant employed in non-traditional medicines that has various therapeutic properties, including anthelmintic, and vasodilatory actions, among others. We evaluated the trachea-relaxant effects of hydroalcoholic extract of R. graveolens against potassium chloride (KCl- and carbachol-induced contraction of rat tracheal rings in an isolated organ bath. RESULTS: The results showed that the airway smooth muscle contraction induced by the depolarizing agent (KCl and cholinergic agonist (carbachol was markedly reduced by R. graveolens in a concentration-dependent manner, with maximum values of 109 ± 7.9 % and 118 ± 2.6 %, respectively (changes in tension expressed as positive percentages of change in proportion to maximum contraction, at the concentration of 45 μg/mL (half-maximal inhibitory concentration IC50: 35.5 μg/mL and 27.8 μg/mL for KCl- and carbachol-induced contraction, respectively. Additionally, the presence of R. graveolens produced rightward parallel displacement of carbachol dose-response curves and reduced over 35 % of the maximum smooth muscle contraction. CONCLUSIONS: The hydroalcoholic extract of R. graveolens exhibited relaxant activity on rat tracheal rings. The results suggest that the trachea-relaxant effect is mediated by a non-competitive antagonistic mechanism. More detailed studies are needed to identify the target of the inhibition, and to determine more precisely the pharmacological mechanisms involved in the observed biological effects.

  18. Flexion-relaxation ratio in computer workers with and without chronic neck pain.

    Science.gov (United States)

    Pinheiro, Carina Ferreira; dos Santos, Marina Foresti; Chaves, Thais Cristina

    2016-02-01

    This study evaluated the flexion-relaxation phenomenon (FRP) and flexion-relaxation ratios (FR-ratios) using surface electromyography (sEMG) of the cervical extensor muscles of computer workers with and without chronic neck pain, as well as of healthy subjects who were not computer users. This study comprised 60 subjects 20-45years of age, of which 20 were computer workers with chronic neck pain (CPG), 20 were computer workers without neck pain (NPG), and 20 were control individuals who do not use computers for work and use them less than 4h/day for other purposes (CG). FRP and FR-ratios were analyzed using sEMG of the cervical extensors. Analysis of FR-ratios showed smaller values in the semispinalis capitis muscles of the two groups of workers compared to the control group. The reference FR-ratio (flexion relaxation ratio [FRR], defined as the maximum activity in 1s of the re-extension/full flexion sEMG activity) was significantly higher in the computer workers with neck pain compared to the CG (CPG: 3.10, 95% confidence interval [CI95%] 2.50-3.70; NPG: 2.33, CI95% 1.93-2.74; CG: 1.99, CI95% 1.81-2.17; pneck pain, and such results suggested that each FR-ratio could have a different application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Mozart versus new age music: relaxation states, stress, and ABC relaxation theory.

    Science.gov (United States)

    Smith, Jonathan C; Joyce, Carol A

    2004-01-01

    Smith's (2001) Attentional Behavioral Cognitive (ABC) relaxation theory proposes that all approaches to relaxation (including music) have the potential for evoking one or more of 15 factor-analytically derived relaxation states, or "R-States" (Sleepiness, Disengagement, Rested / Refreshed, Energized, Physical Relaxation, At Ease/Peace, Joy, Mental Quiet, Childlike Innocence, Thankfulness and Love, Mystery, Awe and Wonder, Prayerfulness, Timeless/Boundless/Infinite, and Aware). The present study investigated R-States and stress symptom-patterns associated with listening to Mozart versus New Age music. Students (N = 63) were divided into three relaxation groups based on previously determined preferences. Fourteen listened to a 28-minute tape recording of Mozart's Eine Kleine Nachtmusik and 14 listened to a 28-minute tape of Steven Halpern's New Age Serenity Suite. Others (n = 35) did not want music and instead chose a set of popular recreational magazines. Participants engaged in their relaxation activity at home for three consecutive days for 28 minutes a session. Before and after each session, each person completed the Smith Relaxation States Inventory (Smith, 2001), a comprehensive questionnaire tapping 15 R-States as well as the stress states of somatic stress, worry, and negative emotion. Results revealed no differences at Session 1. At Session 2, those who listened to Mozart reported higher levels of At Ease/Peace and lower levels of Negative Emotion. Pronounced differences emerged at Session 3. Mozart listeners uniquely reported substantially higher levels of Mental Quiet, Awe and Wonder, and Mystery. Mozart listeners reported higher levels, and New Age listeners slightly elevated levels, of At Ease/Peace and Rested/Refreshed. Both Mozart and New Age listeners reported higher levels of Thankfulness and Love. In summary, those who listened to Mozart's Eine Kleine Nachtmusik reported more psychological relaxation and less stress than either those who listened to

  20. Asymptotic representation of relaxation oscillations in lasers

    CERN Document Server

    Grigorieva, Elena V

    2017-01-01

    In this book we analyze relaxation oscillations in models of lasers with nonlinear elements controlling light dynamics. The models are based on rate equations taking into account periodic modulation of parameters, optoelectronic delayed feedback, mutual coupling between lasers, intermodal interaction and other factors. With the aim to study relaxation oscillations we present the special asymptotic method of integration for ordinary differential equations and differential-difference equations. As a result, they are reduced to discrete maps. Analyzing the maps we describe analytically such nonlinear phenomena in lasers as multistability of large-amplitude relaxation cycles, bifurcations of cycles, controlled switching of regimes, phase synchronization in an ensemble of coupled systems and others. The book can be fruitful for students and technicians in nonlinear laser dynamics and in differential equations.

  1. Relaxation of the magnetization in magnetic molecules

    Science.gov (United States)

    Carretta, S.; Bianchi, A.; Liviotti, E.; Santini, P.; Amoretti, G.

    2006-04-01

    Several mechanisms characterize the relaxation dynamics in magnetic molecules. We investigate two of them, spin-lattice coupling and incoherent quantum tunneling. The effect of the phonon heat bath is studied by analyzing the exponential time decay of the autocorrelation of the magnetization. We show that in ferromagnetic (Cu6) and antiferromagnetic (Fe6) molecular rings this decay is characterized by a single characteristic time. At very low temperature, relaxation through incoherent quantum tunneling may occur in nanomagnets such as Fe8 or Ni4. The mixing between levels with different values of the total spin (S mixing) greatly influences this mechanism. In particular, we demonstrate that a fourth-order anisotropy term O44, required to interpret experimental electron paramagnetic resonance and relaxation data in Ni4, naturally arises when S mixing is considered in calculations.

  2. Excited-state relaxation of some aminoquinolines

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The absorption and fluorescence spectra, fluorescence quantum yields and lifetimes, and fluorescence rate constants ( k f of 2-amino-3-( 2 ′ -benzoxazolylquinoline (I, 2-amino-3-( 2 ′ -benzothiazolylquinoline (II, 2-amino-3-( 2 ′ -methoxybenzothiazolyl-quinoline (III, 2-amino-3-( 2 ′ -benzothiazolylbenzoquinoline (IV at different temperatures have been measured. The shortwavelength shift of fluorescence spectra of compounds studied (23–49 nm in ethanol as the temperature decreases (the solvent viscosity increases points out that the excited-state relaxation process takes place. The rate of this process depends essentially on the solvent viscosity, but not the solvent polarity. The essential increasing of fluorescence rate constant k f (up to about 7 times as the solvent viscosity increases proves the existence of excited-state structural relaxation consisting in the mutual internal rotation of molecular fragments of aminoquinolines studied, followed by the solvent orientational relaxation.

  3. Relaxation oscillation logic in Josephson junction circuits

    International Nuclear Information System (INIS)

    Fulton, T.A.

    1981-01-01

    A dc powered, self-resetting Josephson junction logic circuit relying on relaxation oscillations is described. A pair of Josephson junction gates are connected in series, a first shunt is connected in parallel with one of the gates, and a second shunt is connected in parallel with the series combination of gates. The resistance of the shunts and the dc bias current bias the gates so that they are capable of undergoing relaxation oscillations. The first shunt forms an output line whereas the second shunt forms a control loop. The bias current is applied to the gates so that, in the quiescent state, the gate in parallel with the second shunt is at V O, and the other gate is undergoing relaxation oscillations. By controlling the state of the first gate with the current in the output loop of another identical circuit, the invert function is performed

  4. Muon spin relaxation in ferromagnets. Pt. 1

    International Nuclear Information System (INIS)

    Lovesey, S.W.; Karlsson, E.B.

    1991-04-01

    Expressions for the dipolar and hyperfine contributions to the relaxation rate of muons implanted in a ferromagnet are presented and analysed using the Heisenberg model of spin-waves including dipolar and Zeeman energies. Calculations for EuO indicate that relaxation is likely to be dominated by the hyperfine mechanism, even if the ratio of the hyperfine and dipolar coupling constants is small. The hyperfine mechanism is sensitive to the dipolar energy of the atomic spins, whereas the dipolar mechanisms depend essentially on the exchange energy. For both mechanisms there is an almost quadratic dependence on temperature, throughout much of the ordered magnetic phase, which reflects two-spin-wave difference events from the Raman-type relaxation processes. (author)

  5. Improved memristor-based relaxation oscillator

    KAUST Repository

    Mosad, Ahmed G.

    2013-09-01

    This paper presents an improved memristor-based relaxation oscillator which offers higher frequency and wider tunning range than the existing reactance-less oscillators. It also has the capability of operating on two positive supplies or alternatively a positive and negative supply. Furthermore, it has the advantage that it can be fully integrated on-chip providing an area-efficient solution. On the other hand, The oscillation concept is discussed then a complete mathematical analysis of the proposed oscillator is introduced. Furthermore, the power consumption of the new relaxation circuit is discussed and validated by the PSPICE circuit simulations showing an excellent agreement. MATLAB results are also introduced to demonstrate the resistance range and the corresponding frequency range which can be obtained from the proposed relaxation oscillator. © 2013 Elsevier Ltd.

  6. Relaxation and Diffusion in Complex Systems

    CERN Document Server

    Ngai, K L

    2011-01-01

    Relaxation and Diffusion in Complex Systems comprehensively presents a variety of experimental evidences of universal relaxation and diffusion properties in complex materials and systems. The materials discussed include liquids, glasses, colloids, polymers, rubbers, plastic crystals and aqueous mixtures, as well as carbohydrates, biomolecules, bioprotectants and pharmaceuticals. Due to the abundance of experimental data, emphasis is placed on glass-formers and the glass transition problem, a still unsolved problem in condensed matter physics and chemistry. The evidence for universal properties of relaxation and diffusion dynamics suggests that a fundamental physical law is at work. The origin of the universal properties is traced to the many-body effects of the interaction, rigorous theory of which does not exist at the present time. However, using solutions of simplified models as guides, key quantities have been identified and predictions of the universal properties generated. These predictions from Ngai’...

  7. Electron relaxation properties of Ar magnetron plasmas

    Science.gov (United States)

    Xinjing, CAI; Xinxin, WANG; Xiaobing, ZOU

    2018-03-01

    An understanding of electron relaxation properties in plasmas is of importance in the application of magnetrons. An improved multi-term approximation of the Boltzmann equation is employed to study electron transport and relaxation properties in plasmas. Elastic, inelastic and nonconservative collisions between electrons and neutral particles are considered. The expressions for the transport coefficients are obtained using the expansion coefficients and the collision operator term. Numerical solutions of the matrix equations for the expansion coefficients are also investigated. Benchmark calculations of the Reid model are presented to demonstrate the accuracy of the improved multi-term approximation. It is shown that the two-term approximation is generally not accurate enough and the magnetic fields can reduce the anisotropy of the velocity distribution function. The electron relaxation properties of Ar plasmas in magnetrons for various magnetic fields are studied. It is demonstrated that the energy parameters change more slowly than the momentum parameters.

  8. Intraoperative length and tension curves of human eye muscles. Including stiffness in passive horizontal eye movement in awake volunteers

    NARCIS (Netherlands)

    H.J. Simonsz (Huib); G.H. Kolling (Gerold); H. Kaufmann (Herbert); B. van Dijk (Bob)

    1986-01-01

    textabstractIntraoperative continuous-registration length and tension curves of attached and detached eye muscles were made in 18 strabismic patients under general anesthesia. For relaxed eye muscles, we found an exponential relation between length and tension. An increased stiffness was quantified

  9. Viscoelasticity-based MR elastography of skeletal muscle

    International Nuclear Information System (INIS)

    Klatt, Dieter; Papazoglou, Sebastian; Sack, Ingolf; Braun, Juergen

    2010-01-01

    An in vivo multifrequency magnetic resonance elastography (MRE) protocol was developed for studying the viscoelastic properties of human skeletal muscle in different states of contraction. Low-frequency shear vibrations in the range of 25-62.5 Hz were synchronously induced into the femoral muscles of seven volunteers and measured in a cross-sectional view by encoding the fast-transverse shear wave component parallel to the muscle fibers. The so-called springpot model was used for deriving two viscoelastic constants, μ and α, from the dispersion functions of the complex shear modulus in relaxed and in loaded muscle. Representing the shear elasticity parallel to the muscle fibers, μ increased in all volunteers upon contraction from 2.68 ± 0.23 kPa to 3.87 ± 0.50 kPa. Also α varied with load, indicating a change in the geometry of the mechanical network of muscle from relaxation (α = 0.253 ± 0.009) to contraction (α = 0.270 ± 0.009). These results provide a reference for a future assessment of muscular dysfunction using rheological parameters.

  10. Viscoelasticity-based MR elastography of skeletal muscle

    Science.gov (United States)

    Klatt, Dieter; Papazoglou, Sebastian; Braun, Jürgen; Sack, Ingolf

    2010-11-01

    An in vivo multifrequency magnetic resonance elastography (MRE) protocol was developed for studying the viscoelastic properties of human skeletal muscle in different states of contraction. Low-frequency shear vibrations in the range of 25-62.5 Hz were synchronously induced into the femoral muscles of seven volunteers and measured in a cross-sectional view by encoding the fast-transverse shear wave component parallel to the muscle fibers. The so-called springpot model was used for deriving two viscoelastic constants, μ and α, from the dispersion functions of the complex shear modulus in relaxed and in loaded muscle. Representing the shear elasticity parallel to the muscle fibers, μ increased in all volunteers upon contraction from 2.68 ± 0.23 kPa to 3.87 ± 0.50 kPa. Also α varied with load, indicating a change in the geometry of the mechanical network of muscle from relaxation (α = 0.253 ± 0.009) to contraction (α = 0.270 ± 0.009). These results provide a reference for a future assessment of muscular dysfunction using rheological parameters.

  11. Viscoelasticity-based MR elastography of skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Klatt, Dieter; Papazoglou, Sebastian; Sack, Ingolf [Department of Radiology, Charite-Universitaetsmedizin, Berlin (Germany); Braun, Juergen, E-mail: ingolf.sack@charite.d [Institute of Medical Informatics, Charite-Universitaetsmedizin, Berlin (Germany)

    2010-11-07

    An in vivo multifrequency magnetic resonance elastography (MRE) protocol was developed for studying the viscoelastic properties of human skeletal muscle in different states of contraction. Low-frequency shear vibrations in the range of 25-62.5 Hz were synchronously induced into the femoral muscles of seven volunteers and measured in a cross-sectional view by encoding the fast-transverse shear wave component parallel to the muscle fibers. The so-called springpot model was used for deriving two viscoelastic constants, {mu} and {alpha}, from the dispersion functions of the complex shear modulus in relaxed and in loaded muscle. Representing the shear elasticity parallel to the muscle fibers, {mu} increased in all volunteers upon contraction from 2.68 {+-} 0.23 kPa to 3.87 {+-} 0.50 kPa. Also {alpha} varied with load, indicating a change in the geometry of the mechanical network of muscle from relaxation ({alpha} = 0.253 {+-} 0.009) to contraction ({alpha} = 0.270 {+-} 0.009). These results provide a reference for a future assessment of muscular dysfunction using rheological parameters.

  12. Abrupt relaxation in high-spin molecules

    International Nuclear Information System (INIS)

    Chang, C.-R.; Cheng, T.C.

    2000-01-01

    Mean-field model suggests that the rate of resonant quantum tunneling in high-spin molecules is not only field-dependent but also time-dependent. The relaxation-assisted resonant tunneling in high-spin molecules produces an abrupt magnetization change during relaxation. When the applied field is very close to the resonant field, a time-dependent interaction field gradually shifts the energies of different collective spin states, and magnetization tunneling is observed as two energies of the spin states coincide

  13. Relaxed plasmas in external magnetic fields

    International Nuclear Information System (INIS)

    Spies, G.O.; Li, J.

    1991-08-01

    The well-known theory of relaxed plasmas (Taylor states) is extended to external magnetic fields whose field lines intersect the conducting toroidal boundary. Application to an axially symmetric, large-aspect-ratio torus with circular cross section shows that the maximum pinch ratio, and hence the phenomenon of current saturation, is independent of the external field. The relaxed state is explicitly given for an external octupole field. In this case, field reversal is inhibited near parts of the boundary if the octupole generates magnetic x-points within the plasma. (orig.)

  14. Spin transport and relaxation in graphene

    International Nuclear Information System (INIS)

    Han Wei; McCreary, K.M.; Pi, K.; Wang, W.H.; Li Yan; Wen, H.; Chen, J.R.; Kawakami, R.K.

    2012-01-01

    We review our recent work on spin injection, transport and relaxation in graphene. The spin injection and transport in single layer graphene (SLG) were investigated using nonlocal magnetoresistance (MR) measurements. Spin injection was performed using either transparent contacts (Co/SLG) or tunneling contacts (Co/MgO/SLG). With tunneling contacts, the nonlocal MR was increased by a factor of ∼1000 and the spin injection/detection efficiency was greatly enhanced from ∼1% (transparent contacts) to ∼30%. Spin relaxation was investigated on graphene spin valves using nonlocal Hanle measurements. For transparent contacts, the spin lifetime was in the range of 50-100 ps. The effects of surface chemical doping showed that for spin lifetimes in the order of 100 ps, charged impurity scattering (Au) was not the dominant mechanism for spin relaxation. While using tunneling contacts to suppress the contact-induced spin relaxation, we observed the spin lifetimes as long as 771 ps at room temperature, 1.2 ns at 4 K in SLG, and 6.2 ns at 20 K in bilayer graphene (BLG). Furthermore, contrasting spin relaxation behaviors were observed in SLG and BLG. We found that Elliot-Yafet spin relaxation dominated in SLG at low temperatures whereas Dyakonov-Perel spin relaxation dominated in BLG at low temperatures. Gate tunable spin transport was studied using the SLG property of gate tunable conductivity and incorporating different types of contacts (transparent and tunneling contacts). Consistent with theoretical predictions, the nonlocal MR was proportional to the SLG conductivity for transparent contacts and varied inversely with the SLG conductivity for tunneling contacts. Finally, bipolar spin transport in SLG was studied and an electron-hole asymmetry was observed for SLG spin valves with transparent contacts, in which nonlocal MR was roughly independent of DC bias current for electrons, but varied significantly with DC bias current for holes. These results are very important for

  15. Nonlocal and collective relaxation in stellar systems

    Science.gov (United States)

    Weinberg, Martin D.

    1993-01-01

    The modal response of stellar systems to fluctuations at large scales is presently investigated by means of analytic theory and n-body simulation; the stochastic excitation of these modes is shown to increase the relaxation rate even for a system which is moderately far from instability. The n-body simulations, when designed to suppress relaxation at small scales, clearly show the effects of large-scale fluctuations. It is predicted that large-scale fluctuations will be largest for such marginally bound systems as forming star clusters and associations.

  16. NMR relaxation times of natural rubber latex

    International Nuclear Information System (INIS)

    Harun, S.; Aziz, H.; Basir, Z.

    1994-01-01

    NMR relaxation times T sub 1 and T sub 2 of natural rubber latex have been measured at 25 degree C on a pulsed NMR spectrometer. The work focuses on the variation of the relaxation times with the amount of water content from 0% to 50%. The water content was adjusted by centrifuging and removing a certain amount of water from the sample. The data were analysed using a biexponential fitting procedure which yields simultaneously either T sub 1a and T sub 1b or T sub 2a and T sub 2b. The amount of solid was compared with the known amount of dry rubber content

  17. Green--Kubo formula for collisional relaxation

    International Nuclear Information System (INIS)

    Visscher, P.B.

    1988-01-01

    In this paper we generalize the Green--Kubo method (usually used for obtaining formulas for transport coefficients involving conserved densities) to relaxation processes occurring during collisions, such as the transfer of energy from vibrational to translational modes in a molecular fluid. We show that the relaxation rate can be calculated without evaluating time correlation functions over long times, and can in fact be written as a sum over collisions which makes the relation between the Green--Kubo method and approximate independent-collision models much clearer

  18. Exciton-relaxation dynamics in lead halides

    International Nuclear Information System (INIS)

    Iwanaga, Masanobu; Hayashi, Tetsusuke

    2003-01-01

    We survey recent comprehensive studies of exciton relaxation in the crystals of lead halides. The luminescence and electron-spin-resonance studies have revealed that excitons in lead bromide spontaneously dissociate and both electrons and holes get self-trapped individually. Similar relaxation has been also clarified in lead chloride. The electron-hole separation is ascribed to repulsive correlation via acoustic phonons. Besides, on the basis of the temperature profiles of self-trapped states, we discuss the origin of luminescence components which are mainly induced under one-photon excitation into the exciton band in lead fluoride, lead chloride, and lead bromide

  19. Point defect relaxation volumes for copper

    International Nuclear Information System (INIS)

    Miller, K.M.

    1979-11-01

    The methods used for the determination of point defect relaxation volumes are discussed and it is shown that a previous interatomic potential derived for copper is inaccurate and results obtained using it are invalid. A new interatomic potential has been produced for copper and a computer simulation of point and planar defects carried out. A vacancy relaxation volume of -0.33 atomic volumes has been found with interstitial values in the range 1.7 to 2.0 atomic volumes. It is shown that these values in current theories of irradiation induced swelling lead to an anomalously high value for dislocation bias compared with that determined experimentally. (author)

  20. Strain modulations as a mechanism to reduce stress relaxation in laryngeal tissues.

    Science.gov (United States)

    Hunter, Eric J; Siegmund, Thomas; Chan, Roger W

    2014-01-01

    Vocal fold tissues in animal and human species undergo deformation processes at several types of loading rates: a slow strain involved in vocal fold posturing (on the order of 1 Hz or so), cyclic and faster posturing often found in speech tasks or vocal embellishment (1-10 Hz), and shear strain associated with vocal fold vibration during phonation (100 Hz and higher). Relevant to these deformation patterns are the viscous properties of laryngeal tissues, which exhibit non-linear stress relaxation and recovery. In the current study, a large strain time-dependent constitutive model of human vocal fold tissue is used to investigate effects of phonatory posturing cyclic strain in the range of 1 Hz to 10 Hz. Tissue data for two subjects are considered and used to contrast the potential effects of age. Results suggest that modulation frequency and extent (amplitude), as well as the amount of vocal fold overall strain, all affect the change in stress relaxation with modulation added. Generally, the vocal fold cover reduces the rate of relaxation while the opposite is true for the vocal ligament. Further, higher modulation frequencies appear to reduce the rate of relaxation, primarily affecting the ligament. The potential benefits of cyclic strain, often found in vibrato (around 5 Hz modulation) and intonational inflection, are discussed in terms of vocal effort and vocal pitch maintenance. Additionally, elderly tissue appears to not exhibit these benefits to modulation. The exacerbating effect such modulations may have on certain voice disorders, such as muscle tension dysphonia, are explored.

  1. Nitric oxide and catalase-sensitive relaxation by scutellarin in the mouse thoracic aorta.

    Science.gov (United States)

    Yang, Weimin; Lust, Robert M; Bofferding, April; Wingard, Christopher J

    2009-01-01

    The vascular activity of scutellarin (SCU), a flavonoid isolated from a Chinese traditional medicinal plant, was investigated in isolated thoracic aortic rings of mice. SCU-induced dose-dependent relaxation of phenylephrine (1 microM) stimulated contractions. This relaxation was reduced by endothelium removal, significantly reduced by both the nitric oxide synthase inhibitor (Nomega-nitro-L-arginine methylester, 300 microM) and slightly limited by the soluble guanylyl cyclase inhibitor (1 H-[1,2,4] oxidazolol [4,3-a] quinoxalin-1-one, 100 microM). The catalase inhibitor (3-amino-1,2,4-triazole, 50 mM) augmented the constriction and blocked the lowest SCU concentration relaxation, whereas catalase addition was without effect. Preincubation with 300 and 1000 microM SCU significantly suppressed the contractile dose-response to phenylephrine, causing both a significant rise in half maximal effective concentration and a decrease in the maximal developed force. Western blot analysis showed that SCU inhibition of contraction was independent of reductions in myosin light chain phosphorylation. These results suggested that SCU relaxation was predominantly endothelium dependent and likely involved the catalase-sensitive nitric oxide synthase signaling pathway, without loss of myosin phosphorylation. The potential clinical use of SCU may prove to be effective in increasing vasoreactivity, independently of smooth muscle contractile activity that is mediated by the 20-kDa myosin light chain phosphorylation.

  2. Dynamics of relaxation to a stationary state for interacting molecular motors

    Science.gov (United States)

    Gomes, Luiza V. F.; Kolomeisky, Anatoly B.

    2018-01-01

    Motor proteins are active enzymatic molecules that drive a variety of biological processes, including transfer of genetic information, cellular transport, cell motility and muscle contraction. It is known that these biological molecular motors usually perform their cellular tasks by acting collectively, and there are interactions between individual motors that specify the overall collective behavior. One of the fundamental issues related to the collective dynamics of motor proteins is the question if they function at stationary-state conditions. To investigate this problem, we analyze a relaxation to the stationary state for the system of interacting molecular motors. Our approach utilizes a recently developed theoretical framework, which views the collective dynamics of motor proteins as a totally asymmetric simple exclusion process of interacting particles, where interactions are taken into account via a thermodynamically consistent approach. The dynamics of relaxation to the stationary state is analyzed using a domain-wall method that relies on a mean-field description, which takes into account some correlations. It is found that the system quickly relaxes for repulsive interactions, while attractive interactions always slow down reaching the stationary state. It is also predicted that for some range of parameters the fastest relaxation might be achieved for a weak repulsive interaction. Our theoretical predictions are tested with Monte Carlo computer simulations. The implications of our findings for biological systems are briefly discussed.

  3. Evidence Supports Tradition: The in Vitro Effects of Roman Chamomile on Smooth Muscles

    Directory of Open Access Journals (Sweden)

    Zsolt Sándor

    2018-04-01

    Full Text Available The dried flowers of Chamaemelum nobile (L. All. have been used in traditional medicine for different conditions related to the spasm of the gastrointestinal system. However, there have been no experimental studies to support the smooth muscle relaxant effect of this plant. The aim of our research was to assess the effects of the hydroethanolic extract of Roman chamomile, its fractions, four of its flavonoids (apigenin, luteolin, hispidulin, and eupafolin, and its essential oil on smooth muscles. The phytochemical compositions of the extract and its fractions were characterized and quantified by HPLC-DAD, the essential oil was characterized by GC and GC-MS. Neuronally mediated and smooth muscle effects were tested in isolated organ bath experiments on guinea pig, rat, and human smooth muscle preparations. The crude herbal extract induced an immediate, moderate, and transient contraction of guinea pig ileum via the activation of cholinergic neurons of the gut wall. Purinoceptor and serotonin receptor antagonists did not influence this effect. The more sustained relaxant effect of the extract, measured after pre-contraction of the preparations, was remarkable and was not affected by an adrenergic beta receptor antagonist. The smooth muscle-relaxant activity was found to be associated with the flavonoid content of the fractions. The essential oil showed only the relaxant effect, but no contracting activity. The smooth muscle-relaxant effect was also detected on rat gastrointestinal tissues, as well as on strip preparations of human small intestine. These results suggest that Roman chamomile extract has a direct and prolonged smooth muscle-relaxant effect on guinea pig ileum which is related to its flavonoid content. In some preparations, a transient stimulation of enteric cholinergic motoneurons was also detected. The essential oil also had a remarkable smooth muscle relaxant effect in this setting. Similar relaxant effects were also detected on

  4. Evidence Supports Tradition: The in Vitro Effects of Roman Chamomile on Smooth Muscles.

    Science.gov (United States)

    Sándor, Zsolt; Mottaghipisheh, Javad; Veres, Katalin; Hohmann, Judit; Bencsik, Tímea; Horváth, Attila; Kelemen, Dezső; Papp, Róbert; Barthó, Loránd; Csupor, Dezső

    2018-01-01

    The dried flowers of Chamaemelum nobile (L.) All. have been used in traditional medicine for different conditions related to the spasm of the gastrointestinal system. However, there have been no experimental studies to support the smooth muscle relaxant effect of this plant. The aim of our research was to assess the effects of the hydroethanolic extract of Roman chamomile, its fractions, four of its flavonoids (apigenin, luteolin, hispidulin, and eupafolin), and its essential oil on smooth muscles. The phytochemical compositions of the extract and its fractions were characterized and quantified by HPLC-DAD, the essential oil was characterized by GC and GC-MS. Neuronally mediated and smooth muscle effects were tested in isolated organ bath experiments on guinea pig, rat, and human smooth muscle preparations. The crude herbal extract induced an immediate, moderate, and transient contraction of guinea pig ileum via the activation of cholinergic neurons of the gut wall. Purinoceptor and serotonin receptor antagonists did not influence this effect. The more sustained relaxant effect of the extract, measured after pre-contraction of the preparations, was remarkable and was not affected by an adrenergic beta receptor antagonist. The smooth muscle-relaxant activity was found to be associated with the flavonoid content of the fractions. The essential oil showed only the relaxant effect, but no contracting activity. The smooth muscle-relaxant effect was also detected on rat gastrointestinal tissues, as well as on strip preparations of human small intestine. These results suggest that Roman chamomile extract has a direct and prolonged smooth muscle-relaxant effect on guinea pig ileum which is related to its flavonoid content. In some preparations, a transient stimulation of enteric cholinergic motoneurons was also detected. The essential oil also had a remarkable smooth muscle relaxant effect in this setting. Similar relaxant effects were also detected on other visceral

  5. Operant conditioning of neural activity in freely behaving monkeys with intracranial reinforcement.

    Science.gov (United States)

    Eaton, Ryan W; Libey, Tyler; Fetz, Eberhard E

    2017-03-01

    Operant conditioning of neural activity has typically been performed under controlled behavioral conditions using food reinforcement. This has limited the duration and behavioral context for neural conditioning. To reward cell activity in unconstrained primates, we sought sites in nucleus accumbens (NAc) whose stimulation reinforced operant responding. In three monkeys, NAc stimulation sustained performance of a manual target-tracking task, with response rates that increased monotonically with increasing NAc stimulation. We recorded activity of single motor cortex neurons and documented their modulation with wrist force. We conditioned increased firing rates with the monkey seated in the training booth and during free behavior in the cage using an autonomous head-fixed recording and stimulating system. Spikes occurring above baseline rates triggered single or multiple electrical pulses to the reinforcement site. Such rate-contingent, unit-triggered stimulation was made available for periods of 1-3 min separated by 3-10 min time-out periods. Feedback was presented as event-triggered clicks both in-cage and in-booth, and visual cues were provided in many in-booth sessions. In-booth conditioning produced increases in single neuron firing probability with intracranial reinforcement in 48 of 58 cells. Reinforced cell activity could rise more than five times that of non-reinforced activity. In-cage conditioning produced significant increases in 21 of 33 sessions. In-cage rate changes peaked later and lasted longer than in-booth changes, but were often comparatively smaller, between 13 and 18% above non-reinforced activity. Thus intracranial stimulation reinforced volitional increases in cortical firing rates during both free behavior and a controlled environment, although changes in the latter were more robust. NEW & NOTEWORTHY Closed-loop brain-computer interfaces (BCI) were used to operantly condition increases in muscle and neural activity in monkeys by delivering

  6. On the relation between water pools and water holding capacity in cod muscle

    DEFF Research Database (Denmark)

    Andersen, Charlotte Møller; Jørgensen, Bo

    2004-01-01

    Low-field 1H nuclear magnetic resonance (NMR) relaxations were measured on muscle, minced muscle and centrifuged mince from cod that had been treated under various frozen and chill storage conditions. By using multi-way chemometrics, uni-exponential profiles were obtained, from which the transverse...... relaxation times (T2-values) and the water pool sizes (m- values) were determined. Three pools of water were identified with the different relaxation times and m-values in the centrifuged samples reflecting the removal of loosely bound water. The m-values and the full NMR-signal decays were correlated to two...... measures of water holding capacity (WHC) in a way that WHC related to the original water content could be predicted well for the whole and the minced muscle. The centrifuged samples gave optimal predictions of WHC related to the dry matter content, probably because the centrifuged samples are similar...

  7. Nonmaxwell relaxation in disordered media: Physical mechanisms and fractional relaxation equations

    International Nuclear Information System (INIS)

    Arkhincheev, V.E.

    2004-12-01

    The problem of charge relaxation in disordered systems has been solved. It is shown, that due to the inhomogeneity of the medium the charge relaxation has a non-Maxwell character. The two physical mechanisms of a such behavior have been founded. The first one is connected with the 'fractality' of conducting ways. The second mechanism of nonexponential non-Maxwell behavior is connected with the frequency dispersion of effective conductivity of heterogeneous medium, initially consisting of conducting phases without dispersion. The new generalized relaxation equations in the form of fractional temporal integro-differential equations are deduced. (author)

  8. Energetic aspects of skeletal muscle contraction: implications of fiber types.

    Science.gov (United States)

    Rall, J A

    1985-01-01

    In this chapter fundamental energetic properties of skeletal muscles as elucidated from isolated muscle preparations are described. Implications of these intrinsic properties for the energetic characterization of different fiber types and for the understanding of locomotion have been considered. Emphasis was placed on the myriad of physical and chemical techniques that can be employed to understand muscle energetics and on the interrelationship of results from different techniques. The anaerobic initial processes which liberate energy during contraction and relaxation are discussed in detail. The high-energy phosphate (approximately P) utilized during contraction and relaxation can be distributed between actomyosin ATPase or cross-bridge cycling (70%) and the Ca2+ ATPase of the sacroplasmic reticulum (30%). Muscle shortening increases the rate of approximately P hydrolysis, and stretching a muscle during contraction suppresses the rate of approximately P hydrolysis. The economy of an isometric contraction is defined as the ratio of isometric mechanical response to energetic cost and is shown to be a fundamental intrinsic parameter describing muscle energetics. Economy of contraction varies across the animal kingdom by over three orders of magnitude and is different in different mammalian fiber types. In mammalian skeletal muscles differences in economy of contraction can be attributed mainly to differences in the specific actomyosin and Ca2+ ATPase of muscles. Furthermore, there is an inverse relationship between economy of contraction and maximum velocity of muscle shortening (Vmax) and maximum power output. This is a fundamental relationship. Muscles cannot be economical at developing and maintaining force and also exhibit rapid shortening. Interestingly, there appears to be a subtle system of unknown nature that modulates the Vmax and economy of contraction. Efficiency of a work-producing contraction is defined and contrasted to the economy of contraction

  9. Dynamical relaxation in 2HDM models

    Science.gov (United States)

    Lalak, Zygmunt; Markiewicz, Adam

    2018-03-01

    Dynamical relaxation provides an interesting solution to the hierarchy problem in face of the missing signatures of any new physics in recent experiments. Through a dynamical process taking place in the inflationary phase of the Universe it manages to achieve a small electroweak scale without introducing new states observable in current experiments. Appropriate approximation makes it possible to derive an explicit formula for the final vevs in the double-scanning scenario extended to a model with two Higgs doublets (2HDM). Analysis of the relaxation in the 2HDM confirms that in a general case it is impossible to keep vevs of both scalars small, unless fine-tuning is present or additional symmetries are cast upon the Lagrangian. Within the slightly constrained variant of the 2HDM, where odd powers of the fields’ expectation values are not present (which can be easily enforced by requiring that the doublets have different gauge transformations or by imposing a global symmetry) it is shown that the difference between the vevs of two scalars tends to be proportional to the cutoff. The analysis of the relaxation in 2HDM indicates that in a general case the relaxation would be stopped by the first doublet that gains a vev, with the other one remaining vevless with a mass of the order of the cutoff. This happens to conform with the inert doublet model.

  10. Relaxation of coupled nuclear spin systems

    International Nuclear Information System (INIS)

    Koenigsberger, E.

    1985-05-01

    The subject of the present work is the relaxation behaviour of scalarly coupled spin-1/2 systems. In the theoretical part the semiclassical Redfield equations are used. Dipolar (D), Chemical Shift Anisotropy (CSA) and Random Field (RF) interactions are considered as relaxation mechanisms. Cross correlations of dipolar interactions of different nuclei pairs and those between the D and the CSA mechanisms are important. The model of anisotropic molecular rotational relaxation and the extreme narrowing approximation are used to obtain the spectral density functions. The longitudinal relaxation data are analyzed into normal modes following Werbelow and Grant. The time evolution of normal modes is derived for the AX system with D-CSA cross terms. In the experimental part the hypothesis of dimerization in the cinnamic acid and the methyl cinnamate - AMX systems with DD cross terms - is corroborated by T 1 -time measurements and a calculation of the diffusion constants. In pentachlorobenzene - an AX system - taking into account of D-CSA cross terms enables the complete determination of movements anosotropy and the determination of the sign of the indirect coupling constant 1 Jsub(CH). (G.Q.)

  11. Quantization by stochastic relaxation processes and supersymmetry

    International Nuclear Information System (INIS)

    Kirschner, R.

    1984-01-01

    We show the supersymmetry mechanism resposible for the quantization by stochastic relaxation processes and for the effective cancellation of the additional time dimension against the two Grassmann dimensions. We give a non-perturbative proof of the validity of this quantization procedure. (author)

  12. Charge Relaxation Dynamics of an Electrolytic Nanocapacitor

    Science.gov (United States)

    2015-01-01

    Understanding ion relaxation dynamics in overlapping electric double layers (EDLs) is critical for the development of efficient nanotechnology-based electrochemical energy storage, electrochemomechanical energy conversion, and bioelectrochemical sensing devices as well as the controlled synthesis of nanostructured materials. Here, a lattice Boltzmann (LB) method is employed to simulate an electrolytic nanocapacitor subjected to a step potential at t = 0 for various degrees of EDL overlap, solvent viscosities, ratios of cation-to-anion diffusivity, and electrode separations. The use of a novel continuously varying and Galilean-invariant molecular-speed-dependent relaxation time (MSDRT) with the LB equation recovers a correct microscopic description of the molecular-collision phenomena and enhances the stability of the LB algorithm. Results for large EDL overlaps indicated oscillatory behavior for the ionic current density, in contrast to monotonic relaxation to equilibrium for low EDL overlaps. Further, at low solvent viscosities and large EDL overlaps, anomalous plasmalike spatial oscillations of the electric field were observed that appeared to be purely an effect of nanoscale confinement. Employing MSDRT in our simulations enabled modeling of the fundamental physics of the transient charge relaxation dynamics in electrochemical systems operating away from equilibrium wherein Nernst–Einstein relation is known to be violated. PMID:25678941

  13. Relaxation dynamics of multilayer triangular Husimi cacti

    Science.gov (United States)

    Galiceanu, Mircea; Jurjiu, Aurel

    2016-09-01

    We focus on the relaxation dynamics of multilayer polymer structures having, as underlying topology, the Husimi cactus. The relaxation dynamics of the multilayer structures is investigated in the framework of generalized Gaussian structures model using both Rouse and Zimm approaches. In the Rouse type-approach, we determine analytically the complete eigenvalues spectrum and based on it we calculate the mechanical relaxation moduli (storage and loss modulus) and the average monomer displacement. First, we monitor these physical quantities for structures with a fixed generation number and we increase the number of layers, such that the linear topology will smoothly come into play. Second, we keep constant the size of the structures, varying simultaneously two parameters: the generation number of the main layer, G, and the number of layers, c. This fact allows us to study in detail the crossover from a pure Husimi cactus behavior to a predominately linear chain behavior. The most interesting situation is found when the two limiting topologies cancel each other. For this case, we encounter in the intermediate frequency/time domain regions of constant slope for different values of the parameter set (G, c) and we show that the number of layers follows an exponential-law of G. In the Zimm-type approach, which includes the hydrodynamic interactions, the quantities that describe the mechanical relaxation dynamics do not show scaling behavior as in the Rouse model, except the limiting case, namely, a very high number of layers and low generation number.

  14. Waveform relaxation methods for implicit differential equations

    NARCIS (Netherlands)

    P.J. van der Houwen; W.A. van der Veen

    1996-01-01

    textabstractWe apply a Runge-Kutta-based waveform relaxation method to initial-value problems for implicit differential equations. In the implementation of such methods, a sequence of nonlinear systems has to be solved iteratively in each step of the integration process. The size of these systems

  15. Collection Development: Relaxation & Meditation, September 1, 2010

    Science.gov (United States)

    Lettus, Dodi

    2010-01-01

    One of the first books to document the relationship between stress and physical and emotional health was "The Relaxation Response" by Herbert Benson, M.D., with Miriam Z. Klipper. Originally published in 1975, the book grew out of Benson's observations as a cardiologist and his research as a fellow at Harvard Medical School. Benson's study of…

  16. Relaxation time in confined disordered systems

    International Nuclear Information System (INIS)

    Chamati, H.; Korutcheva, E.

    2006-05-01

    The dynamic critical behavior of a quenched hypercubic sample of linear size L is considered within the 'random T c ' field theoretical model with purely relaxation dynamic (Model A). The dynamic finite size scaling behavior is established and analyzed when the system is quenched from a homogeneous phase towards its critical temperature. The obtained results are compared to those reported in the literature. (author)

  17. Stretched Exponential relaxation in pure Se glass

    Science.gov (United States)

    Dash, S.; Ravindren, S.; Boolchand, P.

    A universal feature of glasses is the stretched exponential relaxation, f (t) = exp[ - t / τ ] β . The model of diffusion of excitations to randomly distributed traps in a glass by Phillips1 yields the stretched exponent β = d[d +2] where d, the effective dimensionality. We have measured the enthalpy of relaxation ΔHnr (tw) at Tg of Se glass in modulated DSC experiments as glasses age at 300K and find β = 0.43(2) for tw in the 0 relaxation is a narrowing of the glass transition width from 7.1°C to 1.4°C, and the ΔHnr term increasing from 0.21 cal/gm to 0.92 cal/gm. In bulk GexSe100-x glasses as x increases to 20%, the length of the polymeric Sen chains between the Ge-crosslinks decreases to n = 2. and the striking relaxation effects nearly vanish. J.C. Phillips, Rep.Prog.Phys. 59 , 1133 (1996). Supported by NSF Grant DMR 08-53957.

  18. Structural relaxation monitored by instantaneous shear modulus

    DEFF Research Database (Denmark)

    Olsen, Niels Boye; Dyre, Jeppe; Christensen, Tage Emil

    1998-01-01

    time definition based on a recently proposed expression for the relaxation time, where G [infinity] reflects the fictive temperature. All parameters entering the reduced time were determined from independent measurements of the frequency-dependent shear modulus of the equilibrium liquid....

  19. Musculoskeletal MRI at 3.0 T and 7.0 T: a comparison of relaxation times and image contrast.

    Science.gov (United States)

    Jordan, Caroline D; Saranathan, Manojkumar; Bangerter, Neal K; Hargreaves, Brian A; Gold, Garry E

    2013-05-01

    The purpose of this study was to measure and compare the relaxation times of musculoskeletal tissues at 3.0 T and 7.0 T, and to use these measurements to select appropriate parameters for musculoskeletal protocols at 7.0 T. We measured the T₁ and T₂ relaxation times of cartilage, muscle, synovial fluid, bone marrow and subcutaneous fat at both 3.0 T and 7.0 T in the knees of five healthy volunteers. The T₁ relaxation times were measured using a spin-echo inversion recovery sequence with six inversion times. The T₂ relaxation times were measured using a spin-echo sequence with seven echo times. The accuracy of both the T₁ and T₂ measurement techniques was verified in phantoms at both magnetic field strengths. We used the measured relaxation times to help design 7.0 T musculoskeletal protocols that preserve the favorable contrast characteristics of our 3.0 T protocols, while achieving significantly higher resolution at higher SNR efficiency. The T₁ relaxation times in all tissues at 7.0 T were consistently higher than those measured at 3.0 T, while the T₂ relaxation times at 7.0 T were consistently lower than those measured at 3.0 T. The measured relaxation times were used to help develop high resolution 7.0 T protocols that had similar fluid-to-cartilage contrast to that of the standard clinical 3.0 T protocols for the following sequences: proton-density-weighted fast spin-echo (FSE), T₂-weighted FSE, and 3D-FSE-Cube. The T₁ and T₂ changes were within the expected ranges. Parameters for musculoskeletal protocols at 7.0 T can be optimized based on these values, yielding improved resolution in musculoskeletal imaging with similar contrast to that of standard 3.0 T clinical protocols. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  20. Musculoskeletal MRI at 3.0 T and 7.0 T: A comparison of relaxation times and image contrast

    International Nuclear Information System (INIS)

    Jordan, Caroline D.; Saranathan, Manojkumar; Bangerter, Neal K.; Hargreaves, Brian A.; Gold, Garry E.

    2013-01-01

    Objective: The purpose of this study was to measure and compare the relaxation times of musculoskeletal tissues at 3.0 T and 7.0 T, and to use these measurements to select appropriate parameters for musculoskeletal protocols at 7.0 T. Materials and methods: We measured the T 1 and T 2 relaxation times of cartilage, muscle, synovial fluid, bone marrow and subcutaneous fat at both 3.0 T and 7.0 T in the knees of five healthy volunteers. The T 1 relaxation times were measured using a spin-echo inversion recovery sequence with six inversion times. The T 2 relaxation times were measured using a spin-echo sequence with seven echo times. The accuracy of both the T 1 and T 2 measurement techniques was verified in phantoms at both magnetic field strengths. We used the measured relaxation times to help design 7.0 T musculoskeletal protocols that preserve the favorable contrast characteristics of our 3.0 T protocols, while achieving significantly higher resolution at higher SNR efficiency. Results: The T 1 relaxation times in all tissues at 7.0 T were consistently higher than those measured at 3.0 T, while the T 2 relaxation times at 7.0 T were consistently lower than those measured at 3.0 T. The measured relaxation times were used to help develop high resolution 7.0 T protocols that had similar fluid-to-cartilage contrast to that of the standard clinical 3.0 T protocols for the following sequences: proton-density-weighted fast spin-echo (FSE), T 2 -weighted FSE, and 3D-FSE-Cube. Conclusion: The T 1 and T 2 changes were within the expected ranges. Parameters for musculoskeletal protocols at 7.0 T can be optimized based on these values, yielding improved resolution in musculoskeletal imaging with similar contrast to that of standard 3.0 T clinical protocols

  1. Muscle activation patterns when passively stretching spastic lower limb muscles of children with cerebral palsy.

    Directory of Open Access Journals (Sweden)

    Lynn Bar-On

    Full Text Available The definition of spasticity as a velocity-dependent activation of the tonic stretch reflex during a stretch to a passive muscle is the most widely accepted. However, other mechanisms are also thought to contribute to pathological muscle activity and, in patients post-stroke and spinal cord injury can result in different activation patterns. In the lower-limbs of children with spastic cerebral palsy (CP these distinct activation patterns have not yet been thoroughly explored. The aim of the study was to apply an instrumented assessment to quantify different muscle activation patterns in four lower-limb muscles of children with CP. Fifty-four children with CP were included (males/females n = 35/19; 10.8 ± 3.8 yrs; bilateral/unilateral involvement n =  32/22; Gross Motor Functional Classification Score I-IV of whom ten were retested to evaluate intra-rater reliability. With the subject relaxed, single-joint, sagittal-plane movements of the hip, knee, and ankle were performed to stretch the lower-limb muscles at three increasing velocities. Muscle activity and joint motion were synchronously recorded using inertial sensors and electromyography (EMG from the adductors, medial hamstrings, rectus femoris, and gastrocnemius. Muscles were visually categorised into activation patterns using average, normalized root mean square EMG (RMS-EMG compared across increasing position zones and velocities. Based on the visual categorisation, quantitative parameters were defined using stretch-reflex thresholds and normalized RMS-EMG. These parameters were compared between muscles with different activation patterns. All patterns were dominated by high velocity-dependent muscle activation, but in more than half, low velocity-dependent activation was also observed. Muscle activation patterns were found to be both muscle- and subject-specific (p<0.01. The intra-rater reliability of all quantitative parameters was moderate to good. Comparing RMS-EMG between

  2. Activation of neural cholecystokinin-1 receptors induces relaxation of the isolated rat duodenum which is reduced by nitric oxide synthase inhibitors

    Directory of Open Access Journals (Sweden)

    S.R. Martins

    2006-02-01

    Full Text Available Cholecystokinin (CCK influences gastrointestinal motility, by acting on central and peripheral receptors. The aim of the present study was to determine whether CCK has any effect on isolated duodenum longitudinal muscle activity and to characterize the mechanisms involved. Isolated segments of the rat proximal duodenum were mounted for the recording of isometric contractions of longitudinal muscle in the presence of atropine and guanethidine. CCK-8S (EC50: 39; 95% CI: 4.1-152 nM and cerulein (EC50: 58; 95% CI: 18-281 nM induced a concentration-dependent and tetrodotoxin-sensitive relaxation. Nomeganitro-L-arginine (L-NOARG reduced CCK-8S- and cerulein-induced relaxation (IC50: 5.2; 95% CI: 2.5-18 µM in a concentration-dependent manner. The magnitude of 300 nM CCK-8S-induced relaxation was reduced by 100 µM L-NOARG from 73 ± 5.1 to 19 ± 3.5% in an L-arginine but not D-arginine preventable manner. The CCK-1 receptor antagonists proglumide, lorglumide and devazepide, but not the CCK-2 receptor antagonist L-365,260, antagonized CCK-8S-induced relaxation in a concentration-dependent manner. These findings suggest that CCK-8S and cerulein activate intrinsic nitrergic nerves acting on CCK-1 receptors in order to cause relaxation of the rat duodenum longitudinal muscle.

  3. Non-invasive assessment of muscle stiffness in patients with Duchenne muscular dystrophy.

    Science.gov (United States)

    Lacourpaille, Lilian; Hug, François; Guével, Arnaud; Péréon, Yann; Magot, Armelle; Hogrel, Jean-Yves; Nordez, Antoine

    2015-02-01

    Assessment of muscle mechanical properties may provide clinically valuable information for follow-up of patients with Duchenne muscular dystrophy (DMD) through the course of their disease. In this study we aimed to assess the effect of DMD on stiffness of relaxed muscles using elastography (supersonic shear imaging). Fourteen DMD patients and 13 control subjects were studied. Six muscles were measured at 2 muscle lengths (shortened and stretched): gastrocnemius medialis (GM); tibialis anterior (TA); vastus lateralis (VL); biceps brachii (BB); triceps brachii (TB); and abductor digiti minimi (ADM). Stiffness was significantly higher in DMD patients compared with controls for all the muscles (main effect for population, P muscle lengths) to large (d = 0.86 for BB/stretched). Supersonic shear imaging is a sensitive non-invasive technique to assess the increase in muscle stiffness associated with DMD. © 2014 Wiley Periodicals, Inc.

  4. Increased muscle belly and tendon stiffness in patients with Parkinson's disease, as measured by myotonometry.

    Science.gov (United States)

    Marusiak, Jarosław; Jaskólska, Anna; Budrewicz, Sławomir; Koszewicz, Magdalena; Jaskólski, Artur

    2011-09-01

    Based on Davis's law, greater tonus of the muscle belly in individuals with Parkinson's disease can create greater tension in the tendon, leading to structural adjustment and an increase in tendon stiffness. Our study aimed to separately assess passive stiffness in the muscle belly and tendon in medicated patients with Parkinson's disease, using myotonometry. We tested 12 patients with Parkinson's disease and 12 healthy matched controls. Passive stiffness of muscle belly and tendon was estimated by myotonometry, electromyography, and mechanomyography in relaxed biceps and triceps brachii muscles. Compared with controls, patients with Parkinson's disease had higher stiffness in the muscle belly and tendon of the biceps brachii and in the tendon of the triceps brachii. In patients with Parkinson's disease, there was a positive correlation between muscle belly stiffness and parkinsonian rigidity in the biceps brachii. Patients with Parkinson's disease have higher passive stiffness of the muscle belly and tendon than healthy matched controls. Copyright © 2011 Movement Disorder Society.

  5. Regulation and dysregulation of esophageal peristalsis by the integrated function of circular and longitudinal muscle layers in health and disease

    OpenAIRE

    Mittal, Ravinder K.

    2016-01-01

    Muscularis propria throughout the entire gastrointestinal tract including the esophagus is comprised of circular and longitudinal muscle layers. Based on the studies conducted in the colon and the small intestine, for more than a century, it has been debated whether the two muscle layers contract synchronously or reciprocally during the ascending contraction and descending relaxation of the peristaltic reflex. Recent studies in the esophagus and colon prove that the two muscle layers indeed c...

  6. Electron spin-lattice relaxation in fractals

    International Nuclear Information System (INIS)

    Shrivastava, K.N.

    1986-08-01

    We have developed the theory of the spin-fracton interaction for paramagnetic ions in fractal structures. The interaction is exponentially damped by the self-similarity length of the fractal and by the range dimensionality d Φ . The relaxation time of the spin due to the absorption and emission of the fracton has been calculated for a general dimensionality called the Raman dimensionality d R , which for the fractons differs from the Hausdorff (fractal) dimensionality, D, as well as from the Euclidean dimensionality, d. The exponent of the energy level separation in the relaxation rate varies with d R d Φ /D. We have calculated the spin relaxation rate due to a new type of Raman process in which one fracton is absorbed to affect a spin transition from one electronic level to another and later another fracton is emitted along with a spin transition such that the difference in the energies of the two fractons is equal to the electronic energy level separation. The temperature and the dimensionality dependence of such a process has been found in several approximations. In one of the approximations where the van Vleck relaxation rate for a spin in a crystal is known to vary with temperature as T 9 , our calculated variation for fractals turns out to be T 6.6 , whereas the experimental value for Fe 3+ in frozen solutions of myoglobin azide is T 6.3 . Since we used d R =4/3 and the fracton range dimensionality d Φ =D/1.8, we expect to measure the dimensionalities of the problem by measuring the temperature dependence of the relaxation times. We have also calculated the shift of the paramagnetic resonance transition for a spin in a fractal for general dimensionalities. (author)

  7. The Whisper Relaxation Sounder onboard Cluster: A Powerful Tool for Space Plasma Diagnosis around the Earth

    International Nuclear Information System (INIS)

    Trotignon, J.G.; Decreau, P.M.E.; Rauch, J.L.; LeGuirriec, E.; Canu, P.; Darrouzet, F.

    2001-01-01

    The WHISPER relaxation sounder that is onboard the four CLUSTER spacecraft has for main scientific objectives to monitor the natural waves in the 2 kHz - 80 kHz frequency range and, mostly, to determine the total plasma density from the solar wind down to the Earth's plasmasphere. To fulfil these objectives, the WHISPER uses the two long double sphere antennae of the Electric Field and Wave experiment as transmitting and receiving sensors. In its active working mode, the WHISPER works according to principles that have been worked out for topside sounding. A radio wave transmitter sends an almost monochromatic and short wave train. A few milliseconds after, a receiver listens to the surrounding plasma response. Strong and long lasting echoes are actually received whenever the transmitting frequencies coincide with characteristic plasma frequencies. Provided that these echoes, also called resonances, may be identified, the WHISPER relaxation sounder becomes a reliable and powerful tool for plasma diagnosis. When the transmitter is off, the WHISPER behaves like a passive receiver, allowing natural waves to be monitored. The paper aims mainly at the resonance identification process description and the WHISPER capabilities and performance highlighting. (author)

  8. Evaluation of PHB/Clay nanocomposite by spin-lattice relaxation time

    Directory of Open Access Journals (Sweden)

    Mariana Bruno

    2008-12-01

    Full Text Available Poly(3-hydroxybutyrate (PHB based on nanocomposites containing different amounts of a commercial organically modified clay (viscogel B7 were prepared employing solution intercalation method. Three solvents, such as: CHCl3, dimethylchloride (DMC and tetrahydrofuran (THF were used. The relationship among the processing conditions; molecular structure and intermolecular interaction, between both nanocomposite components, were investigated using a nuclear magnetic resonance (NMR, as a part of characterization methodology, which has been used by Tavares et al. It involves the hydrogen spin-lattice relaxation time, T1H, by solid state nuclear magnetic resonance, employing low field NMR. X ray diffraction was also employed because it is a conventional technique, generally used to obtain the first information on nanocomposite formation. Changes in PHB crystallinity were observed after the organophilic nanoclay had been incorporated in the polymer matrix. These changes, in the microstructure, were detected by the variation of hydrogen nuclear relaxation time values and by X ray, which showed an increase in the clay interlamelar space due to the intercalation of the polymer in the clay between lamellae. It was also observed, for both techniques, that the solvents affect directly the organization of the crystalline region, promoting a better intercalation, considering that they behave like a plasticizer.

  9. Diffusion processes in the relaxed cross sections for the reaction 107109Ag+20Ne

    International Nuclear Information System (INIS)

    Babinet, R.; Moretto, L.G.; Galin, J.; Jared, R.; Moulton, J.; Thompson, S.G.

    1976-01-01

    The fragments emitted in the reaction 107 109 Ag+ 20 Ne at 175 and 252 MeV bombarding energy have been identified in charge up to Z=32. Kinetic energy distributions, cross sections and angular distributions have been measured for each Z. The kinetic energy spectra show the two usual components: the quasielastic component and the relaxed component. The Z-distribution of the latter is fairly flat, slowly decreasing up to Z approximately 15 and then rising again up to Z=30. The variations in the Z-distribution are more pronounced at the lower bombarding energy. The angular distributions associated with the relaxed component are forward peaked for Z-values close to that of the projectile and behave like 1/sintheta for larger Z-values. The forward peaking is very substantial for Z 10 the forward peaking in excess of 1/sintheta disappears around Z=15. These features are interpreted in terms of a diffusion process along the asymmetry coordinate of a short-lived intermediate complex. (Auth.)

  10. Assessment of muscle fatigue after an ultra-endurance triathlon using tensiomyography (TMG).

    Science.gov (United States)

    García-Manso, Juan Manuel; Rodríguez-Ruiz, David; Rodríguez-Matoso, Dario; de Saa, Yves; Sarmiento, Samuel; Quiroga, Miriam

    2011-03-01

    In this study, we used tensiomyography (TMG) to assess muscle status immediately after an ultra-endurance triathlon. Maximal radial displacement or deformation of the muscle belly, contraction time, delay time, sustain time, and relaxation time were measured for both legs, and dependent t-tests were used to compare means between the beginning and end of the race. The 19 men assessed (age 37.9 ± 7.1 years; height 177.5 ± 4.6 cm; weight: 73.6 ± 6.5 kg) participated in the 2009 edition of the Lanzarote Ironman. Deterioration in the neural response was observed for contraction time (P = 0.008) and relaxation time (P = 0.011), with a moderate decrease in the response time (sustain time) and a loss in muscle stiffness (deformation of the muscle belly). The effect of muscle fatigue on the rectus femoris and biceps femoris was different. Barely any changes in contraction time, relaxation time, sustain time, and deformation of the muscle belly were observed, while only the contraction response time decreased to a significant extent (reduction in delay time; P = 0.003). The considerable loss in contractile capacity induced by a long-distance race was reflected in changes in the neuromuscular response and fluctuations in the contractile capacity of the muscle. These modifications, derived from a prolonged, exhausting effort, can be assessed in a simple, non-aggressive, non-invasive way using tensiomyography.

  11. Static respiratory muscle work during immersion with positive and negative respiratory loading.

    Science.gov (United States)

    Taylor, N A; Morrison, J B

    1999-10-01

    Upright immersion imposes a pressure imbalance across the thorax. This study examined the effects of air-delivery pressure on inspiratory muscle work during upright immersion. Eight subjects performed respiratory pressure-volume relaxation maneuvers while seated in air (control) and during immersion. Hydrostatic, respiratory elastic (lung and chest wall), and resultant static respiratory muscle work components were computed. During immersion, the effects of four air-delivery pressures were evaluated: mouth pressure (uncompensated); the pressure at the lung centroid (PL,c); and at PL,c +/-0.98 kPa. When breathing at pressures less than the PL,c, subjects generally defended an expiratory reserve volume (ERV) greater than the immersed relaxation volume, minus residual volume, resulting in additional inspiratory muscle work. The resultant static inspiratory muscle work, computed over a 1-liter tidal volume above the ERV, increased from 0.23 J. l(-1), when subjects were breathing at PL,c, to 0.83 J. l(-1) at PL,c -0.98 kPa (P work was minimal. When breathing at PL,c +0.98 kPa, subjects adopted an ERV less than the immersed relaxation volume, minus residual volume, resulting in 0.36 J. l(-1) of expiratory muscle work. Thus static inspiratory muscle work varied with respiratory loading, whereas PL,c air supply minimized this work during upright immersion, restoring lung-tissue, chest-wall, and static muscle work to levels obtained in the control state.

  12. Method to Measure Tone of Axial and Proximal Muscle

    Science.gov (United States)

    Gurfinkel, Victor S.; Cacciatore, Timothy W.; Cordo, Paul J.; Horak, Fay B.

    2011-01-01

    The control of tonic muscular activity remains poorly understood. While abnormal tone is commonly assessed clinically by measuring the passive resistance of relaxed limbs1, no systems are available to study tonic muscle control in a natural, active state of antigravity support. We have developed a device (Twister) to study tonic regulation of axial and proximal muscles during active postural maintenance (i.e. postural tone). Twister rotates axial body regions relative to each other about the vertical axis during stance, so as to twist the neck, trunk or hip regions. This twisting imposes length changes on axial muscles without changing the body's relationship to gravity. Because Twister does not provide postural support, tone must be regulated to counteract gravitational torques. We quantify this tonic regulation by the restive torque to twisting, which reflects the state of all muscles undergoing length changes, as well as by electromyography of relevant muscles. Because tone is characterized by long-lasting low-level muscle activity, tonic control is studied with slow movements that produce "tonic" changes in muscle length, without evoking fast "phasic" responses. Twister can be reconfigured to study various aspects of muscle tone, such as co-contraction, tonic modulation to postural changes, tonic interactions across body segments, as well as perceptual thresholds to slow axial rotation. Twister can also be used to provide a quantitative measurement of the effects of disease on axial and proximal postural tone and assess the efficacy of intervention. PMID:22214974

  13. Muscle glycogen and cell function--Location, location, location.

    Science.gov (United States)

    Ørtenblad, N; Nielsen, J

    2015-12-01

    The importance of glycogen, as a fuel during exercise, is a fundamental concept in exercise physiology. The use of electron microscopy has revealed that glycogen is not evenly distributed in skeletal muscle fibers, but rather localized in distinct pools. In this review, we present the available evidence regarding the subcellular localization of glycogen in skeletal muscle and discuss this from the perspective of skeletal muscle fiber function. The distribution of glycogen in the defined pools within the skeletal muscle varies depending on exercise intensity, fiber phenotype, training status, and immobilization. Furthermore, these defined pools may serve specific functions in the cell. Specifically, reduced levels of these pools of glycogen are associated with reduced SR Ca(2+) release, muscle relaxation rate, and membrane excitability. Collectively, the available literature strongly demonstrates that the subcellular localization of glycogen has to be considered to fully understand the role of glycogen metabolism and signaling in skeletal muscle function. Here, we propose that the effect of low muscle glycogen on excitation-contraction coupling may serve as a built-in mechanism, which links the energetic state of the muscle fiber to energy utilization. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Resistance to rocuronium of rat diaphragm as compared with limb muscles.

    Science.gov (United States)

    Huang, Lina; Yang, Meirong; Chen, Lianhua; Li, Shitong

    2014-12-01

    Skeletal muscles are composed of different muscle fiber types. We investigated the different potency to rocuronium among diaphragm (DIA), extensor digitorum longus (EDL), and soleus (SOL) in vitro as well as to investigate the differences of acetylcholine receptors (AChRs) among these three typical kinds of muscles. The isolated left hemidiaphragm nerve-muscle preparations, the EDL sciatic nerve-muscle preparations, and the SOL sciatic nerve-muscle preparations were established to evaluate the potency to rocuronium. Concentration-response curves were constructed and the values of IC50 were obtained. The density of AChRs at the end plate and the number of AChRs per unit fiber cross fiber area (CSA), AChR affinity for muscle relaxants were evaluated. The concentration-twitch tension curves of rocuronium were significantly different. The curves demonstrated a shift to the right of the DIA compared with the EDL and SOL (P  0.05). IC50 was significantly largest in DIA, second largest in SOL, and smallest in EDL (P rocuronium of DIA compared with EDL and SOL was verified. The DIA was characterized by the largest number of AChRs per unit fiber CSA and the lowest affinity of the AChRs. Although compared with SOL, EDL was proved to have larger number of AChRs per unit fiber CSA and the lower affinity of the AChRs. These findings may be the mechanisms of different potency to rocuronium in DIA, EDL, and SOL. The results of the study could help to explain the relationship between different composition of muscle fibers and the potency to muscle relaxants. Extra caution should be taken in clinical practice when monitoring muscle relaxation in anesthetic management using different muscles. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. A COMPARATIVE STUDY OF EFFICACY OF EMG BIO-FEEDBACK AND PROGRESSIVE MUSCULAR RELAXATION IN TENSION HEADACHE1

    Science.gov (United States)

    Gada, M.T.

    1984-01-01

    SUMMARY The aim of the present study was to find out efficacy of frontalis EMG Biofeedback therapy, deep muscular relaxation therapy and compare the efficacy of both in cases of tension headache. During two week basal-data recording period all patients were taught deep muscular relaxation by Jacobson′s technique. Simultaneously patients were instructed to keep headache diary. Headache diary yielded three different parameters a) number of headache-free days per week, b) peak headache intensity (or each week and c) average daily headache activity score per week. These parameters were used to find out therapeutic efficacy of each treatment. Patients were randomly divided in two groups. EMG Biofeedback group was given frontalis EMG feedback through EMG J 33 muscle trainer of Cyborg Corporation (U.S.A.). Patients in each group were given 20 sessions (two sessions per week); each session lasting 30 minutes. Patients were instructed to practice at least one 30 minute session of relaxation at home. The data were subjected to statistical calculation. The results indicate that frontalis EMG Biofeedback therapy and deep muscle relaxation therapy are significantly effective in cases of tension headache. Both treatments are equally effective. The findings are discussed in relation to Indian situation. PMID:21965970

  16. A comparative study of efficacy of emg bio-feedback and progressive muscular relaxation in tension headache.

    Science.gov (United States)

    Gada, M T

    1984-04-01

    The aim of the present study was to find out efficacy of frontalis EMG Biofeedback therapy, deep muscular relaxation therapy and compare the efficacy of both in cases of tension headache. During two week basal-data recording period all patients were taught deep muscular relaxation by Jacobson's technique. Simultaneously patients were instructed to keep headache diary. Headache diary yielded three different parameters a) number of headache-free days per week, b) peak headache intensity (or each week and c) average daily headache activity score per week. These parameters were used to find out therapeutic efficacy of each treatment. Patients were randomly divided in two groups. EMG Biofeedback group was given frontalis EMG feedback through EMG J 33 muscle trainer of Cyborg Corporation (U.S.A.). Patients in each group were given 20 sessions (two sessions per week); each session lasting 30 minutes. Patients were instructed to practice at least one 30 minute session of relaxation at home. The data were subjected to statistical calculation. The results indicate that frontalis EMG Biofeedback therapy and deep muscle relaxation therapy are significantly effective in cases of tension headache. Both treatments are equally effective. The findings are discussed in relation to Indian situation.

  17. Bitter Taste Receptors in The Wrong Place: Novel Airway Smooth Muscle Targets For Treating Asthma

    OpenAIRE

    Liggett, Stephen B.

    2014-01-01

    There is a need to expand the classes of drugs used to treat obstructive lung diseases to achieve better outcomes. With only one class of direct bronchodilators (β-agonists), we sought to find receptors on human airway smooth muscle (ASM) that act via a unique mechanism to relax the muscle, have a diverse agonist binding profile to enhance the probability of finding new therapeutics, and relax ASM with equal or greater efficacy than β-agonists. We have found that human and mouse ASM express s...

  18. RELATIONSHIPS BETWEEN MUSCLE FATIGUE CHARACTERISTICS AND MARKERS OF ENDURANCE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Martyn G. Morris

    2008-12-01

    Full Text Available The aim of this study was to examine the relationship of a range of in-vivo whole muscle characteristics to determinants of endurance performance. Eleven healthy males completed a cycle ergometer step test to exhaustion for the determination of the lactate threshold, gross mechanical efficiency, peak power and VO2max. On two separate occasions, contractile and fatigue characteristics of the quadriceps femoris were collected using a specially designed isometric strength-testing chair. Muscle fatigue was then assessed by stimulating the muscle for 3 minutes. Force, rate of force development and rates of relaxation were calculated at the beginning and end of the 3 minute protocol and examined for reliability and in relation to lactate threshold, VO2max, gross mechanical efficiency and peak power. Muscle characteristics, rate of force development and relaxation rate were demonstrated to be reliable measures. Force drop off over the 3 minutes (fatigue index was related to lactate threshold (r = -0.72 p < 0.01 but not to VO2max. The rate of force development related to the peak power at the end of the cycle ergometer test (r = -0.75 p < 0.01. Rates of relaxation did not relate to any of the performance markers. We found in-vivo whole muscle characteristics, such as the fatigue index and rate of force development, relate to specific markers of peripheral, but not to central, fitness components. Our investigation suggests that muscle characteristics assessed in this way is reliable and could be feasibly utilised to further our understanding of the peripheral factors underpinning performance

  19. Transport and relaxation properties of superfluid 3He. I. Kinetic equation and Bogoliubov quasiparticle relaxation rate

    International Nuclear Information System (INIS)

    Einzel, D.; Woelfle, P.

    1978-01-01

    The kinetic equation for Bogoliubov quasiparticles for both the A and B phases of superfluid 3 He is derived from the general matrix kinetic equation. A condensed expression for the exact spin-symmetric collision integral is given. The quasiparticle relaxation rate is calculated for the BW state using the s--p approximation for the quasiparticle scattering amplitude. By using the results for the quasiparticle relaxation rate, the mean free path of Bogoliubov quasiparticles is calculated for all temperatures

  20. Influence of glutamate-evoked pain and sustained elevated muscle activity on blood oxygenation in the human masseter muscle.

    Science.gov (United States)

    Suzuki, Shunichi; Arima, Taro; Kitagawa, Yoshimasa; Svensson, Peter; Castrillon, Eduardo

    2017-12-01

    This study aimed to investigate the effect of glutamate-evoked masseter muscle pain on intramuscular oxygenation during rest and sustained elevated muscle activity (SEMA). Seventeen healthy individuals participated in two sessions in which they were injected with glutamate and saline in random order. Each session was divided into three, 10-min periods. During the first (period 1) and the last (period 3) 10-min periods, participants performed five intercalated 1-min bouts of masseter SEMA with 1-min periods of 'rest'. At onset of the second 10-min period, glutamate (0.5 ml, 1 M; Ajinomoto, Tokyo, Japan) or isotonic saline (0.5 ml; 0.9%) was injected into the masseter muscle and the participants kept the muscle relaxed in a resting position for 10 min (period 2). The hemodynamic characteristics of the masseter muscle were recorded simultaneously during the experiment by a laser blood-oxygenation monitor. The results demonstrated that glutamate injections caused significant levels of self-reported pain in the masseter muscle; however, this nociceptive input did not have robust effects on intramuscular oxygenation during rest or SEMA tasks. Interestingly, these findings suggest an uncoupling between acute nociceptive activity and hemodynamic parameters in both resting and low-level active jaw muscles. Further studies are needed to explore the pathophysiological significance of blood-flow changes for persistent jaw-muscle pain conditions. © 2017 Eur J Oral Sci.

  1. Change in muscle thickness under contracting conditions following return to sports after a hamstring muscle strain injury—A pilot study

    Directory of Open Access Journals (Sweden)

    Yasuharu Nagano

    2015-04-01

    Full Text Available The purpose of this study was to measure the change in hamstring muscle thickness between contracting and relaxing conditions following a return to sports after a hamstring muscle strain and thereby evaluate muscle function. Six male track and field sprinters participated in this study. All had experienced a prior hamstring strain injury that required a minimum of 2 weeks away from sport participation. Transverse plane scans were performed at the following four points on the affected and unaffected sides under contracting and relaxing conditions: proximal biceps femoris long head, proximal semitendinosus, middle biceps femoris long head, and middle semitendinosus. The results demonstrated an increase in the thickness of the middle biceps femoris long head and middle semitendinosus regions on the unaffected side with contraction, whereas the affected side did not show a significant increase. The proximal semitendinosus muscle thickness was increased with contraction on both the unaffected and the affected sides. By contrast, the proximal biceps femoris muscle thickness did not show a significant increase on both sides. The results of this study show that evaluation of muscle thickness during contraction may be useful for assessing the change in muscle function after a hamstring muscle strain injury.

  2. Regional thermal specialisation in a mammal: temperature affects power output of core muscle more than that of peripheral muscle in adult mice (Mus musculus).

    Science.gov (United States)

    James, Rob S; Tallis, Jason; Angilletta, Michael J

    2015-01-01

    In endotherms, such as mammals and birds, internal organs can specialise to function within a narrow thermal range. Consequently, these organs should become more sensitive to changes in body temperature. Yet, organs at the periphery of the body still experience considerable fluctuations in temperature, which could select for lower thermal sensitivity. We hypothesised that the performance of soleus muscle taken from the leg would depend less on temperature than would the performance of diaphragm muscle taken from the body core. Soleus and diaphragm muscles were isolated from mice and subjected to isometric and work-loop studies to analyse mechanical performance at temperatures between 15 and 40 °C. Across this thermal range, soleus muscle took longer to generate isometric force and longer to relax, and tended to produce greater normalised maximal force (stress) than did diaphragm muscle. The time required to produce half of maximal force during isometric tetanus and the time required to relax half of maximal force were both more sensitive to temperature in soleus than they were in diaphragm. However, thermal sensitivities of maximal force during isometric tetani were similar for both muscles. Consistent with our hypothesis, power output (the product of speed and force) was greater in magnitude and more thermally sensitive in diaphragm than it was in soleus. Our findings, when combined with previous observations of muscles from regionally endothermic fish, suggest that endothermy influences the thermal sensitivities of power output in core and peripheral muscles.

  3. Study of the response of the penile corporal tissue and cavernosus muscles to micturition

    Directory of Open Access Journals (Sweden)

    El Sibai Olfat

    2008-03-01

    Full Text Available Abstract Background The reaction of the corpora cavernosa (CC, the corpus spongiosum (CS, the bulbocavernosus (BCM and ischiocavernosus (ICM muscles to passage of urine through the urethra during micturition is not known. We investigated the hypothesis that the passage of urine through the urethra stimulates the corporal tissue and cavernosus muscles. Methods In 30 healthy men (mean age 42.8 ± 11.7 years, the electromyographic activity (EMG of the CC, CS, BCM, and ICM were recorded before and during micturition, and on interruption of and straining during micturition. These tests were repeated after individual anesthetization of urethra, corporal tissue, and cavernosus muscles. Results During micturition, the slow wave variables (frequency, amplitude, conduction velocity of the CC and CS decreased while the motor unit action potentials of the BCM and ICM increased; these EMG changes were mild and returned to the basal values on interruption or termination of micturition. Micturition after individual anesthetization of urethra, corporal tissue and cavernosal muscles did not effect significant EMG changes in these structures, while saline administration produced changes similar to those occurring before saline administration. Conclusion The decrease of sinusoidal and increase of cavernosus muscles' EMG activity during micturition apparently denotes sinusoidal relaxation and cavernosus muscles contraction. Sinusoidal muscle relaxation and cavernosus muscles contraction upon micturition are suggested to be mediated through a 'urethro-corporocavernosal reflex'. These sinusoidal and cavernosus muscle changes appear to produce a mild degree of penile tumescence and stretch which might assist in urinary flow during micturition.

  4. Biotransformation of glyceryl trinitrate occurs concurrently with relaxation of rabbit aorta

    International Nuclear Information System (INIS)

    Brien, J.F.; McLaughlin, B.E.; Breedon, T.H.; Bennett, B.M.; Nakatsu, K.; Marks, G.S.

    1986-01-01

    This study was conducted to test the hypothesis that biotransformation of glyceryl trinitrate (GTN) is involved in GTN-induced relaxation of vascular smooth muscle. Isolated rabbit aortic strips (RAS) were contracted submaximally with phenylephrine (PE) and then were incubated with 0.5 microM [ 14 C]GTN in a time course study. GTN-induced relaxation (inhibition of PE-induced tone) of RAS was monitored and tissue GTN and glyceryl-1,2- and 1,3-dinitrate (GDN) concentrations were measured by thin-layer chromatography and liquid scintillation spectrometry at 0.5, 1, 2 and 20 min after incubation. Biotransformation of GTN to GDN occurred during GTN-induced relaxation of RAS. The tissue GDN concentration was dependent on the time duration of incubation with GTN and was related to the magnitude of GTN-induced tissue relaxation. At the 20-min interval, the GDN concentration in the incubation medium indicated appreciable efflux of GDN metabolites from the RAS. In the biotransformation of GTN by RAS, there was about 4-fold preferential formation of 1,2-GDN compared with 1,3-GDN. RAS were made tolerant to GTN in vitro by incubation with 500 microM GTN for 1 hr. After washing, GTN-tolerant and nontolerant (incubation with vehicle for 1 hr) RAS were contracted submaximally with PE, and then were incubated with 0.5 microM [ 14 C]GTN for 2 min. GTN-induced relaxation of RAS and tissue GDN concentration were significantly less for GTN-tolerant tissue compared with nontolerant tissue. Tissue GTN concentration was similar for both GTN-tolerant and nontolerant RAS, which indicated that the tissue uptake of GTN was similar and that GTN biotransformation was diminished in tolerant tissue.(ABST

  5. EFFICACY OF POST ISOMETRIC RELAXATION VERSUS STATIC STRECHING IN SUBJECTS WITH CHRONIC NON SPECIFIC NECK PAIN

    Directory of Open Access Journals (Sweden)

    P.Haritha

    2015-12-01

    Full Text Available Background: Neck pain is a common problem within our society. Upper trapezius sternocleidomastoid and the levator scapulae are the most common postural muscles that tends to get shorten leading to restricted neck mobility. There is lack of evidence to allow conclusions to be drawn about the effectiveness of post isometric relaxation when compared with static stretching exercises. The aim is to find out the effectiveness of Post isometric relaxation Versus Static stretching in the subjects with chronic nonspecific neck pain. To evaluate the effectiveness of post isometric relaxation technique on pain by using Visual analoge scale, range of motion by using Universal Goniometry, and functional disability by using Neck Disability Index in chronic nonspecific neck pain. Methods: A convenient sample of thirty seven subjects was diagnosed with nonspecific neck pain was randomly allocated to one of the two treatment groups on the basis of the inclusion criteria. The experimental group (n=15 received three sessions of post isometric relaxation technique for trapezius, sternocleidomastoid and the levator scapulae and control group (n=15 received the three sessions of static stretching for trapezius, sternocliedomastiod and levator scapulae for four weeks. Results: Non parametric tests demonstrated a statistically significant difference with experimental group showing greater improvement in ROM, VAS, and NDI than the control group and significant difference within the group also. Conclusion: This study concluded and the results reflected that post isometric relaxation technique group had better improvement in reduction of pain, improvement in the range of motion, and increased neck functional activities than the static stretching group.

  6. Excess L-arginine restores endothelium-dependent relaxation impaired by monocrotaline pyrrole

    International Nuclear Information System (INIS)

    Cheng Wei; Oike, Masahiro; Hirakawa, Masakazu; Ohnaka, Keizo; Koyama, Tetsuya; Ito, Yushi

    2005-01-01

    The pyrrolizidine alkaloid plant toxin monocrotaline pyrrole (MCTP) causes pulmonary hypertension in experimental animals. The present study aimed to examine the effects of MCTP on the endothelium-dependent relaxation. We constructed an in vitro disease model of pulmonary hypertension by overlaying MCTP-treated bovine pulmonary artery endothelial cells (CPAEs) onto pulmonary artery smooth muscle cell-embedded collagen gel lattice. Acetylcholine (Ach) induced a relaxation of the control CPAEs-overlaid gels that were pre-contracted with noradrenaline, and the relaxation was inhibited by L-NAME, an inhibitor of NO synthase (NOS). In contrast, when MCTP-treated CPAEs were overlaid, the pre-contracted gels did not show a relaxation in response to Ach in the presence of 0.5 mM L-arginine. Expression of endothelial NOS protein, Ach-induced Ca 2+ transients and cellular uptake of L-[ 3 H]arginine were significantly smaller in MCTP-treated CPAEs than in control cells, indicating that these changes were responsible for the impaired NO production in MCTP-treated CPAEs. Since cellular uptake of L-[ 3 H]arginine linearly increased according to its extracellular concentration, we hypothesized that the excess concentration of extracellular L-arginine might restore NO production in MCTP-treated CPAEs. As expected, in the presence of 10 mM L-arginine, Ach showed a relaxation of the MCTP-treated CPAEs-overlaid gels. These results indicate that the impaired NO production in damaged endothelial cells can be reversed by supplying excess L-arginine

  7. Kaempferol enhances endothelium-dependent relaxation in the porcine coronary artery through activation of large-conductance a2+-activated K+ channels

    Science.gov (United States)

    Xu, Y C; Leung, S W S; Leung, G P H; Man, R Y K

    2015-01-01

    Background and Purpose Kaempferol, a plant flavonoid present in normal human diet, can modulate vasomotor tone. The present study aimed to elucidate the signalling pathway through which this flavonoid enhanced relaxation of vascular smooth muscle. Experimental Approach The effect of kaempferol on the relaxation of porcine coronary arteries to endothelium-dependent (bradykinin) and -independent (sodium nitroprusside) relaxing agents was studied in an in vitro organ chamber setup. The whole-cell patch-clamp technique was used to determine the effect of kaempferol on potassium channels in porcine coronary artery smooth muscle cells (PCASMCs). Key Results At a concentration without direct effect on vascular tone, kaempferol (3 × 10−6 M) enhanced relaxations produced by bradykinin and sodium nitroprusside. The potentiation by kaempferol of the bradykinin-induced relaxation was not affected by Nω-nitro-L-arginine methyl ester, an inhibitor of NO synthase (10−4 M) or TRAM-34 plus UCL 1684, inhibitors of intermediate- and small-conductance calcium-activated potassium channels, respectively (10−6 M each), but was abolished by tetraethylammonium chloride, a non-selective inhibitor of calcium-activated potassium channels (10−3 M), and iberiotoxin, a selective inhibitor of large-conductance calcium-activated potassium channel (KCa1.1; 10−7 M). Iberiotoxin also inhibited the potentiation by kaempferol of sodium nitroprusside-induced relaxations. Kaempferol stimulated an outward-rectifying current in PCASMCs, which was abolished by iberiotoxin. Conclusions and Implications The present results suggest that, in smooth muscle cells of the porcine coronary artery, kaempferol enhanced relaxations caused by endothelium-derived and exogenous NO as well as those due to endothelium-dependent hyperpolarization. This vascular effect of kaempferol involved the activation of KCa1.1 channels. PMID:25652142

  8. Kaempferol enhances endothelium-dependent relaxation in the porcine coronary artery through activation of large-conductance Ca(2+) -activated K(+) channels.

    Science.gov (United States)

    Xu, Y C; Leung, S W S; Leung, G P H; Man, R Y K

    2015-06-01

    Kaempferol, a plant flavonoid present in normal human diet, can modulate vasomotor tone. The present study aimed to elucidate the signalling pathway through which this flavonoid enhanced relaxation of vascular smooth muscle. The effect of kaempferol on the relaxation of porcine coronary arteries to endothelium-dependent (bradykinin) and -independent (sodium nitroprusside) relaxing agents was studied in an in vitro organ chamber setup. The whole-cell patch-clamp technique was used to determine the effect of kaempferol on potassium channels in porcine coronary artery smooth muscle cells (PCASMCs). At a concentration without direct effect on vascular tone, kaempferol (3 × 10(-6) M) enhanced relaxations produced by bradykinin and sodium nitroprusside. The potentiation by kaempferol of the bradykinin-induced relaxation was not affected by N(ω)-nitro-L-arginine methyl ester, an inhibitor of NO synthase (10(-4) M) or TRAM-34 plus UCL 1684, inhibitors of intermediate- and small-conductance calcium-activated potassium channels, respectively (10(-6) M each), but was abolished by tetraethylammonium chloride, a non-selective inhibitor of calcium-activated potassium channels (10(-3) M), and iberiotoxin, a selective inhibitor of large-conductance calcium-activated potassium channel (KCa 1.1; 10(-7) M). Iberiotoxin also inhibited the potentiation by kaempferol of sodium nitroprusside-induced relaxations. Kaempferol stimulated an outward-rectifying current in PCASMCs, which was abolished by iberiotoxin. The present results suggest that, in smooth muscle cells of the porcine coronary artery, kaempferol enhanced relaxations caused by endothelium-derived and exogenous NO as well as those due to endothelium-dependent hyperpolarization. This vascular effect of kaempferol involved the activation of KCa 1.1 channels. © 2015 The British Pharmacological Society.

  9. Vibrational Energy Relaxation in Water-Acetonitrile Mixtures

    NARCIS (Netherlands)

    Cringus, Dan; Yeremenko, Sergey; Pshenichnikov, Maxim S.; Wiersma, Douwe A.; Kobayashi, Takayoshi; Kobayashi, Tetsuro; Nelson, Keith A.; Okada, Tadashi; Silvestri, Sandro De

    2004-01-01

    IR pump-probe spectroscopy is used to study the effect of hydrogen bonding on the vibrational energy relaxation pathways. Hydrogen bonding accelerates the population relaxation from 12ps in diluted acetonitrile solution to 700fs in bulk water.

  10. Exploiting Sparsity in SDP Relaxation for Sensor Network Localization

    NARCIS (Netherlands)

    S. Kim (Sunyoung); M. Kojima; H. Waki (Hayato)

    2008-01-01

    htmlabstract A sensor network localization problem can be formulated as a quadratic optimization problem (QOP). For quadratic optimization problems, semidefinite programming (SDP) relaxation by Lasserre with relaxation order 1 for general polynomial optimization problems (POPs) is known to be

  11. Exploiting Sparsity in SDP Relaxation for Sensor Network Localization

    NARCIS (Netherlands)

    S. Kim (Sunyoung); M. Kojima; H. Waki (Hayato)

    2009-01-01

    htmlabstract A sensor network localization problem can be formulated as a quadratic optimization problem (QOP). For quadratic optimization problems, semidefinite programming (SDP) relaxation by Lasserre with relaxation order 1 for general polynomial optimization problems (POPs) is known to be

  12. Synthetic tactile perception induced by transcranial alternating-current stimulation can substitute for natural sensory stimulus in behaving rabbits.

    Science.gov (United States)

    Márquez-Ruiz, Javier; Ammann, Claudia; Leal-Campanario, Rocío; Ruffini, Giulio; Gruart, Agnès; Delgado-García, José M

    2016-01-21

    The use of brain-derived signals for controlling external devices has long attracted the attention from neuroscientists and engineers during last decades. Although much effort has been dedicated to establishing effective brain-to-computer communication, computer-to-brain communication feedback for "closing the loop" is now becoming a major research theme. While intracortical microstimulation of the sensory cortex has already been successfully used for this purpose, its future application in humans partly relies on the use of non-invasive brain stimulation technologies. In the present study, we explore the potential use of transcranial alternating-current stimulation (tACS) for synthetic tactile perception in alert behaving animals. More specifically, we determined the effects of tACS on sensory local field potentials (LFPs) and motor output and tested its capability for inducing tactile perception using classical eyeblink conditioning in the behaving animal. We demonstrated that tACS of the primary somatosensory cortex vibrissa area could indeed substitute natural stimuli during training in the associative learning paradigm.

  13. Mechanically, the shoot apical meristem of Arabidopsis behaves like a shell inflated by a pressure of about 1 MPa

    Directory of Open Access Journals (Sweden)

    Léna eBeauzamy

    2015-11-01

    Full Text Available In plants, the shoot apical meristem contains the stem cells and is responsible for the generation of all aerial organs. Mechanistically, organogenesis is associated with an auxin-dependent local softening of the epidermis. This has been proposed to be sufficient to trigger outgrowth, because the epidermis is thought to be under tension and stiffer than internal tissues in all the aerial part of the plant. However, this has not been directly demonstrated in the shoot apical meristem. Here we tested this hypothesis in Arabidopsis using indentation methods and modeling. We considered two possible scenarios: either the epidermis does not have unique properties and the meristem behaves as a homogeneous linearly-elastic tissue, or the epidermis is under tension and the meristem exhibits the response of a shell under pressure. Large indentation depths measurements with a large tip (~size of the meristem were consistent with a shell-like behavior. This also allowed us to deduce a value of turgor pressure, estimated at 0.82 ± 0.16 MPa. Indentation with atomic force microscopy provided local measurements of pressure in the epidermis, further confirming the values obtained from large deformations. Altogether, our data demonstrate that the Arabidopsis shoot apical meristem behaves like a shell under a MPa range pressure and support a key role for the epidermis in shaping the shoot apex.

  14. Chronic monitoring of cortical hemodynamics in behaving, freely-moving rats using a miniaturized head-mounted optical microscope

    Science.gov (United States)

    Sigal, Iliya; Gad, Raanan; Koletar, Margaret; Ringuette, Dene; Stefanovic, Bojana; Levi, Ofer

    2016-03-01

    Growing interest within the neurophysiology community in assessing healthy and pathological brain activity in animals that are awake and freely-behaving has triggered the need for optical systems that are suitable for such longitudinal studies. In this work we report label-free multi-modal imaging of cortical hemodynamics in the somatosensory cortex of awake, freely-behaving rats, using a novel head-mounted miniature optical microscope. The microscope employs vertical cavity surface emitting lasers (VCSELs) at three distinct wavelengths (680 nm, 795 nm, and 850 nm) to provide measurements of four hemodynamic markers: blood flow speeds, HbO, HbR, and total Hb concentration, across a > 2 mm field of view. Blood flow speeds are extracted using Laser Speckle Contrast Imaging (LSCI), while oxygenation measurements are performed using Intrinsic Optical Signal Imaging (IOSI). Longitudinal measurements on the same animal are made possible over the course of > 6 weeks using a chronic window that is surgically implanted into the skull. We use the device to examine changes in blood flow and blood oxygenation in superficial cortical blood vessels and tissue in response to drug-induced absence-like seizures, correlating motor behavior with changes in blood flow and blood oxygenation in the brain.

  15. Healthy Muscles Matter

    Science.gov (United States)

    ... or lying down, and faster when you’re running or playing sports and your skeletal muscles need more blood to help them do their work. What can go wrong? Injuries Almost everyone has had sore muscles after exercising ...

  16. Muscle emulation with DC motor and neural networks for biped robots.

    Science.gov (United States)

    Serhan, Hayssam; Nasr, Chaiban G; Henaff, Patrick

    2010-08-01

    This paper shows how to use a DC motor and its PID controller, to behave analogously to a muscle. A model of the muscle that has been learned by a NNARX (Neural Network Auto Regressive eXogenous) structure is used. The PID parameters are tuned by an MLP Network with a special indirect online learning algorithm. The calculation of the learning algorithm is performed based on a mathematical equation of the DC motor or with a Neural Network identification of the motor. For each of the two algorithms, the output of the muscle model is used as a reference for the DC motor control loop. The results show that we succeeded in forcing the physical system to behave in the same way as the muscle model with acceptable margin of error. An implementation in the knees of a simulated biped robot is realized. Simulation compares articular trajectories with and without the muscle emulator and shows that with muscle emulator, articular trajectories become closer to the human being ones and that total power consumption is reduced.

  17. The effect of unilateral partial edentulism to muscle thickness

    International Nuclear Information System (INIS)

    Koca-Ceylan, Golzem; Guler, Ahmet U.; Taskay-Yelmir, Nergiz; Lutfi, Incesu; Aksoz, Tolga

    2003-01-01

    Teeth and muscle play a very important role for occlusal equilibrium and function.when tooth loss begins ,it may also effect the function of muscle tissues. The thickness of masseter and anterior temporalis muscles were measured bilaterally in 30 healthy fully dentate adults and in 30 unilateral edentulous patients by using ultrasonographic imaging. All scans were carried out by the same radiologist to eliminate the inter-observer difference, using a real time scanner (Toshiba SSA -270A,Japan). A 7.5 MHz linear transducer was used. The effect of age, sex, duration of partial edentulism, unilateral chewing habits of the individuals to the muscle thickness were also evaluated. In all subjects,facial proportion index was also determined. Main purpose of this study was to compare and establish the differences of muscle thickness between dentate and edentulous side in unilateral partial edentulous patients with ultrasonography and to test whether the variation in the thickness of the muscle is related to the variation in the facial and morphology. Ultrasonography revealed a large variation in the thickness of the masseter and temporolis muscles in experimental and controlled groups ,both relaxed and contracted conditions.The thickness of muscles in females was less in both conditions.In experimental group, a high negative correlation was found between the thickness of the masseter muscle and Facial Proportion Index ( FPI) in the females ,however, the statistical analysis showed no significant difference in the males. Also a high negative correlation was found in female control group. There was no statistically significant relationship between unilateral chewing habits and muscle thickness .In this study the duration of partial edentulism did not affect the thickness of the muscle.Further research is required to study muscular atrophy for comparison with total edentulism. (author)

  18. Multi-region relaxed magnetohydrodynamics with flow

    Energy Technology Data Exchange (ETDEWEB)

    Dennis, G. R., E-mail: graham.dennis@anu.edu.au; Dewar, R. L.; Hole, M. J. [Research School of Physics and Engineering, Australian National University, ACT 0200 (Australia); Hudson, S. R. [Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543 (United States)

    2014-04-15

    We present an extension of the multi-region relaxed magnetohydrodynamics (MRxMHD) equilibrium model that includes plasma flow. This new model is a generalization of Woltjer's model of relaxed magnetohydrodynamics equilibria with flow. We prove that as the number of plasma regions becomes infinite, our extension of MRxMHD reduces to ideal MHD with flow. We also prove that some solutions to MRxMHD with flow are not time-independent in the laboratory frame, and instead have 3D structure which rotates in the toroidal direction with fixed angular velocity. This capability gives MRxMHD potential application to describing rotating 3D MHD structures such as 'snakes' and long-lived modes.

  19. Dissipation and the relaxation to equilibrium

    International Nuclear Information System (INIS)

    Evans, Denis J; Williams, Stephen R; Searles, Debra J

    2009-01-01

    Using the recently derived dissipation theorem and a corollary of the transient fluctuation theorem (TFT), namely the second-law inequality, we derive the unique time independent, equilibrium phase space distribution function for an ergodic Hamiltonian system in contact with a remote heat bath. We prove under very general conditions that any deviation from this equilibrium distribution breaks the time independence of the distribution. Provided temporal correlations decay, we show that any nonequilibrium distribution that is an even function of the momenta eventually relaxes (not necessarily monotonically) to the equilibrium distribution. Finally we prove that the negative logarithm of the microscopic partition function is equal to the thermodynamic Helmholtz free energy divided by the thermodynamic temperature and Boltzmann's constant. Our results complement and extend the findings of modern ergodic theory and show the importance of dissipation in the process of relaxation towards equilibrium

  20. Active nematic gels as active relaxing solids

    Science.gov (United States)

    Turzi, Stefano S.

    2017-11-01

    I propose a continuum theory for active nematic gels, defined as fluids or suspensions of orientable rodlike objects endowed with active dynamics, that is based on symmetry arguments and compatibility with thermodynamics. The starting point is our recent theory that models (passive) nematic liquid crystals as relaxing nematic elastomers. The interplay between viscoelastic response and active dynamics of the microscopic constituents is naturally taken into account. By contrast with standard theories, activity is not introduced as an additional term of the stress tensor, but it is added as an external remodeling force that competes with the passive relaxation dynamics and drags the system out of equilibrium. In a simple one-dimensional channel geometry, we show that the interaction between nonuniform nematic order and activity results in either a spontaneous flow of particles or a self-organization into subchannels flowing in opposite directions.