WorldWideScience

Sample records for mg nifedipine slow

  1. Perbandingan Pengaruh Nifedipin 20 mg per Oral 2 Jam Preoperasi dengan Plasebo terhadap Suhu Inti pada Pasien yang Menjalani Operasi Modified Radical Mastectomy dengan Anestesi Umum

    Directory of Open Access Journals (Sweden)

    Saleh Trisnadi

    2014-08-01

    Full Text Available Strategy of prevention the initial redistribution hypothermia is based on the reduction of the heat gradient between the core and perifer before surgery by administering vasodilators. The purpose of this study was to asses the effect of oral nifedipine 20 mg 2 hours before anesthesia in preventing hypothermia in patients undergoing modified radical mastectomy under general anesthesia and to compare the decreased rate of body temperature oral nifedipine with placebo. The research was done with the prospective method, randomized double-blind controlled study in 30 patients aged 18–60 yrs, American Society of Anesthesiologist (ASA physical status I-II, underwent modified radical mastectomy surgery, were randomly divided into two groups at Dr. Hasan Sadikin General Hospital Bandung during June until August 2012. One group was given oral nifedipine 20 mg 2 hours before general anesthesia and the other group was given placebo. Tymphani temperature was recorded during anesthesia every 10 minutes. Research data was tested statistically by the Mann-Whitney test. The average core temperature in the nifedipine was 36.37 ° C which was higher than the control group 35.61 ° C (p<0.05. It can be concluded that the use of nifedipine can prevent intraoperative hypothermia.

  2. Maintenance nifedipine therapy for preterm symptomatic placenta previa: A randomized, multicenter, double-blind, placebo-controlled trial.

    Directory of Open Access Journals (Sweden)

    Eric Verspyck

    Full Text Available To assess the impact of maintenance nifedipine therapy on pregnancy duration in women with preterm placenta previa bleeding.PPADAL was a randomized, double-blind, placebo-controlled trial conducted between 05/2008 and 05/2012 in five French hospitals. The trial included 109 women, aged ≥ 18 years, with at least one episode of placenta previa bleeding, intact membranes and no other pregnancy complication, at gestational age 24 to 34 weeks and after 48 hours of complete acute tocolysis. Women were randomly allocated to receive either 20 mg of slow-release nifedipine three times daily (n = 54 or placebo (n = 55 until 36 + 6 weeks of gestation. The primary outcome for the trial was length of pregnancy measured in days after enrolment. Main secondary outcomes were rates of recurrent bleeding, cesarean delivery due to hemorrhage, blood transfusion, maternal side effects, gestational age at delivery and adverse perinatal outcomes (perinatal death, chronic lung disease, neonatal sepsis, intraventricular hemorrhage > grade 2, perventricular leukomalacia > grade 1, or necrotizing enterocolitis. Analysis was by intention to treat.Mean (SD prolongation of pregnancy was not different between the nifedipine (n = 54 and the placebo (n = 55 group; 42.5 days ± 23.8 versus 44.2 days ± 24.5, p = 0.70. Cesarean due to hemorrhage performed before 37 weeks occurred more frequently in the nifedipine group in comparison with the placebo group (RR, 1.66; 95% confidence interval, 1.05-2.72. Adverse perinatal outcomes were comparable between groups; 3.8% for nifedipine versus 5.5% for placebo (relative risk, 0.52; 95% confidence interval 0.10-2.61. No maternal mortality or perinatal death occurred.Maintenance oral nifedipine neither prolongs duration of pregnancy nor improves maternal or perinatal outcomes.ClinicalTrials.gov NCT00620724.

  3. Nifedipine and thallium-201 myocardial perfusion in progressive systemic sclerosis

    International Nuclear Information System (INIS)

    Kahan, A.; Devaux, J.Y.; Amor, B.

    1986-01-01

    Heart disease in patients with progressive systemic sclerosis may be due in part to myocardial ischemia caused by a disturbance of the coronary microcirculation. To determine whether abnormalities of myocardial perfusion in this disorder are potentially reversible, we evaluated the effect of the coronary vasodilator nifedipine on myocardial perfusion assessed by thallium-201 scanning in 20 patients. Thallium-201 single-photon-emission computerized tomography was performed under control conditions and 90 minutes after 20 mg of oral nifedipine. The mean (+/- SD) number of left ventricular segments with perfusion defects decreased from 5.3 +/- 2.0 to 3.3 +/- 2.2 after nifedipine (P = 0.0003). Perfusion abnormalities were quantified by a perfusion score (0 to 2.0) assigned to each left ventricular segment and by a global perfusion score (0 to 18) for the entire left ventricle. The mean perfusion score in segments with resting defects increased from 0.97 +/- 0.24 to 1.26 +/- 0.44 after nifedipine (P less than 0.00001). The mean global perfusion score increased from 11.2 +/- 1.7 to 12.8 +/- 2.4 after nifedipine (P = 0.003). The global perfusion score increased by at least 2.0 in 10 patients and decreased by at least 2.0 in only 1. These observations reveal short-term improvement in thallium-201 myocardial perfusion with nifedipine in patients with progressive systemic sclerosis. The results are consistent with a potentially reversible abnormality of coronary vasomotion in this disorder, but the long-term therapeutic effects of nifedipine remain to be determined

  4. Electroreduction of nifedipine.

    Science.gov (United States)

    Ellaithy, M M; Zuman, P

    1992-02-01

    At pH greater than 6, the nitro group of nifedipine is reduced in a four-electron step to a hydroxylamino group. At pH less than 6, the hydroxylamino derivative undergoes an acid-catalyzed dehydration, and the rate of this reaction governs the limiting current. Resulting quinonemethide is further reduced, and a six-electron reduction step results. Formation and reducibility of the quinonemethide is favored by conjugation with the 1,4-dihydropyridine ring. Further reduction of the hydroxylamino derivative is confirmed by the absence of the anodic oxidation peak on the reverse scan at pH less than 6.5. At potentials more negative than that of the nitro group, the protonated form of the hydroxylamino derivative is reduced between pH 4 and 8 in direct current (dc) polarography and between pH 6 and 11 in cyclic voltammetry, the difference resulting from the difference in the measurement time window. The yields and fate of the hydroxylamino derivative obtained in controlled potential electrolysis with a hanging mercury drop electrode (HMDE) differ from those in dc polarography, indicating the presence of different competing reactions. For analyses, pH 2 and 11 are most suitable.

  5. Pharmacokinetic Study of Nifedipine in Healthy Adult Male Human ...

    African Journals Online (AJOL)

    Erah

    obtained from the volunteers. Nifedipine (Adalat® capsules, 10 mg, Bayer. Pharmaceuticals, Karachi, Pakistan) was the drug used. The study was conducted in the same subjects in two phases separated by a washout period of one week. Twelve data sets were obtained. Drug administration and blood sampling. A blank ...

  6. Nifedipine--a calcium channel blocker--in asthmatic patients. Interaction with terbutaline.

    Science.gov (United States)

    Svedmyr, K; Löfdahl, C G; Svedmyr, N

    1984-01-01

    Seven asthmatic patients were studied in a single-blind randomized, crossover study after oral administration of 20 mg nifedipine or placebo. Four increasing doses of i.v. terbutaline were then given with 30 min interval. The study was concluded with inhalation of five terbutaline puffs. FEV1 measurements 30 min after intake of nifedipine did not show any difference compared to placebo. During the terbutaline treatment, however, there was a more pronounced bronchodilation after nifedipine than after placebo (P less than 0.05). Terbutaline-induced skeletal muscle tremor was similar after nifedipine and placebo pretreatments. After nifedipine intake there was a decrease of diastolic blood pressure and a reflexogenic tachycardia. Thus, this study showed a small potentiation of the beta 2-adrenoceptor mediated bronchodilation, which is of importance when treating patients with simultaneous asthma and hypertension or angina pectoris.

  7. Compound list: nifedipine [Open TG-GATEs

    Lifescience Database Archive (English)

    Full Text Available nifedipine NIF 00091 ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Human/i...n_vitro/nifedipine.Human.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vi...tro/nifedipine.Rat.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Liv...er/Single/nifedipine.Rat.in_vivo.Liver.Single.zip ftp://ftp.biosciencedbc.jp/arch

  8. Validación de un método espectrofotométrico para la cuantificación de principio activo en tabletas de nifedipino 10 mg Validation of a spectrophotometric method for quantification of the active principle in 10 mg Nifedipine tablets

    Directory of Open Access Journals (Sweden)

    Yalexmi Ramos Rodríguez

    2008-12-01

    Full Text Available Se realizó la validación de una técnica espectrofotométrica para la cuantificación del principio activo en tabletas de nifedipino 10 mg con el empleo de etanol al 96 % como solvente. Se determinaron los parámetros de linealidad, exactitud, precisión intermedia, repetibilidad, especificidad y robustez. Se comprobó que el método es lineal, exacto y preciso en un rango de 85 a 115 %, lo que demuestra la fiabilidad del método y su posibilidad de empleo en el control de la calidad de la forma terminada.The validation of a spectrophotometric method for the determination of active principle in tablets of nifedipine 10 mg is presented in this work. The linearity, precision, exactitude, specificity and robustness of the method were evaluated. The method employed was linear, exact and precise in the interval of 85 % to 115%. This proves that the method can be used in the tablets' quality control.

  9. Pharmacokinetic profile of nifedipine GITS in hypertensive patients with chronic renal impairment.

    Science.gov (United States)

    Schneider, R; Stolero, D; Griffel, L; Kobelt, R; Brendel, E; Iaina, A

    1994-01-01

    25 hypertensive patients with normal or impaired renal function underwent pharmacokinetic and safety studies after single and multiple dose administration of nifedipine GITS (Gastro-Intestinal Therapeutic System) 60mg tablets. Complete pharmacokinetic data were obtained from 23 of these patients. Blood pressure and heart rate changes were compatible with the known properties of the drug. Impaired renal function did not affect the maximum plasma concentrations or bioavailability of nifedipine after single or multiple dose administration of nifedipine GITS, nor was there any evidence of excessive drug accumulation in the presence of renal impairment.

  10. An oral modified-release nifedipine tablet (Adalat LA) and its appearance on double contrast barium enema

    International Nuclear Information System (INIS)

    Bleehen, Robert E.

    2000-01-01

    Adalat LA 30 mg and 60 mg tablets are widely prescribed oral modified release nifedipine preparations with a porous, non-digestible plastic tablet coating which is required in order to effect the osmotically driven slow release mechanism. These tablets may therefore be seen anywhere along the gastrointestinal tract and are passed apparently whole in the faeces. An example of the appearance within the rectum of Adalat LA 30 (Bayer) on double contrast barium enema is shown and the main features described. A review of the literature is given. Recognition of the appearances during the barium enema examination will prompt those performing the procedure to question the drug history where relevant and will reduce the incidence of false-positive reporting. Bleehen, R.E. (2000)

  11. [Management of pre-term labor: use of nifedipine in Conakry, Guinea].

    Science.gov (United States)

    Sy, T; Diallo, F B; Diallo, Y; Camara, M K; Diallo, A; Cissoko, M; Lontsi, G R; Diallo, M S

    2010-04-01

    This purpose of this prospective and descriptive study was to evaluate the utility of a calcium-channel inhibitor, i.e. nifedipine, for management of preterm labor in our work setting in terms of safety and cost-effectiveness in comparison with betamimetics classically used for this indication. Study was carried out over a six-month period in the department of Gynecology-Obstetrics Department of Ignace Deen National Hospital in Conakry, Guinea. Pregnant women meeting the following criteria were included: 28 to 33 weeks of amenorrhea, six days of hospitalization either for preterm labor or for another diagnosis that was associated with the occurrence of preterm labor during hospitalization, and absence of contraindications for tocolysis using nifedipine. A total of 42 women were included. Pregnancy was extended for more than 48 hours after the first dose of nifedipine in 86.8% of cases. Administration of nifedipine failed in 5 cases including one case in which it was necessary to change the tocolytic and 4 cases in which delivery occurred less than 48 hours after the first dose of nifedipine. In 68% of cases, 90 mg of nifedipine were sufficient to stop uterine contractions within 48 hours. In 39.5% of cases, no side effects were observed. Adverse effects in the other cases were dizziness (39.5%) and headache (18.4%). The mean term of delivery was 36 weeks +/- 5 days of amenorrhea with a mean extension of 6.2 weeks. Apgar score was low in 30.5% of the newborns and normal in 69.5%. One newborn (2.8%) died. The results of this study indicate that nifedipine is an effective, economical and safe drug for tocolysis and that it can be used as an alternative to betamimetis in countries with limited resources. An information campaign is needed to promote use of nifedipine as a tocolytic in obstetrical facilities of our country.

  12. Surface modification of an Mg-1Ca alloy to slow down its biocorrosion by chitosan

    International Nuclear Information System (INIS)

    Gu, X N; Zheng, Y F; Lan, Q X; Cheng, Y; Xi, T F; Zhang, Z X; Zhang, D Y

    2009-01-01

    The surface morphologies before and after immersion corrosion test of various chitosan-coated Mg-1Ca alloy samples were studied to investigate the effect of chitosan dip coating on the slowdown of biocorrosion. It showed that the corrosion resistance of the Mg-Ca alloy increased after coating with chitosan, and depended on both the chitosan molecular weight and layer numbers of coating. The Mg-Ca alloy coated by chitosan with a molecular weight of 2.7 x 10 5 for six layers has smooth and intact surface morphology, and exhibits the highest corrosion resistance in a simulated body fluid.

  13. Surface modification of an Mg-1Ca alloy to slow down its biocorrosion by chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X N; Zheng, Y F; Lan, Q X [State Key Laboratory for Turbulence and Complex System and College of Engineering, Peking University, Beijing 100871 (China); Cheng, Y; Xi, T F [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhang, Z X [Biomedical Engineering Research Center, Research Institute of Peking University in Shenzhen, Shenzhen 518057 (China); Zhang, D Y, E-mail: gxn139888@pku.edu.c, E-mail: yfzheng@pku.edu.c, E-mail: 8lanqiuxiang@163.co, E-mail: chengyan@pku.edu.c, E-mail: top5460@163.co, E-mail: xitingfei@tom.co, E-mail: zhangdeyuan@lifetechmed.co [Lifetech Scientific (Shenzhen) Co. Ltd, Hi-Tech Park, Shenzhen 518000 (China)

    2009-08-15

    The surface morphologies before and after immersion corrosion test of various chitosan-coated Mg-1Ca alloy samples were studied to investigate the effect of chitosan dip coating on the slowdown of biocorrosion. It showed that the corrosion resistance of the Mg-Ca alloy increased after coating with chitosan, and depended on both the chitosan molecular weight and layer numbers of coating. The Mg-Ca alloy coated by chitosan with a molecular weight of 2.7 x 10{sup 5} for six layers has smooth and intact surface morphology, and exhibits the highest corrosion resistance in a simulated body fluid.

  14. Surface modification of an Mg-1Ca alloy to slow down its biocorrosion by chitosan.

    Science.gov (United States)

    Gu, X N; Zheng, Y F; Lan, Q X; Cheng, Y; Zhang, Z X; Xi, T F; Zhang, D Y

    2009-08-01

    The surface morphologies before and after immersion corrosion test of various chitosan-coated Mg-1Ca alloy samples were studied to investigate the effect of chitosan dip coating on the slowdown of biocorrosion. It showed that the corrosion resistance of the Mg-Ca alloy increased after coating with chitosan, and depended on both the chitosan molecular weight and layer numbers of coating. The Mg-Ca alloy coated by chitosan with a molecular weight of 2.7 x 10(5) for six layers has smooth and intact surface morphology, and exhibits the highest corrosion resistance in a simulated body fluid.

  15. Nonsurgical Management of Nifedipine Induced Gingival Overgrowth

    Directory of Open Access Journals (Sweden)

    George Sam

    2014-01-01

    Full Text Available Drug-induced gingival overgrowth is frequently associated with three particular drugs: phenytoin, cyclosporin, and nifedipine. As gingival enlargement develops, it affects the normal oral hygiene practice and may interfere with masticatory functions. The awareness in the medical community about this possible side effect of nifedipine is less when compared to the effects of phenytoin and cyclosporin. The frequency of gingival enlargement associated with chronic nifedipine therapy remains controversial. Within the group of patients that develop this unwanted effect, there appears to be variability in the extent and severity of the gingival changes. Although gingival inflammation is considered a primary requisite in their development, few cases with minimal or no plaque induced gingival inflammation have also been reported. A case report of gingival overgrowth induced by nifedipine in a patient with good oral hygiene and its nonsurgical management with drug substitution is discussed in this case report.

  16. "Nifedipine in the treatment of liver toxicity induced by Acetaminophen overdose in mice "

    Directory of Open Access Journals (Sweden)

    Kalantari H

    2000-11-01

    Full Text Available Acetaminophen is an analgesic and antipyretic drug, which is widely used by public and poisoning with this drug, is common. One of the most important adverse effects of acetaminophen poisoning is centrilobullar necrosis in hepatic cells, which depends on activity of microsomal cytochrome P-450 (CYP enzymes. The aim of this investigation was to find out the protective effect of nifedipine against liver toxicity caused by acetaminophen overdose (700 mg/kg as calcium channel blocker. In this study doses of 5, 50, 100, 250, 500 mg/kg of nifedipine were administered to mice orally one hour before acetaminophen administration. The negative control group receive normal saline. The positive control group was administered with acetaminophen at a dose of 700 mg/kg one hour after nifedipine administration. After 24 hours, enzyme activity (ALT, AST, histopathological examination and liver weight were compared with the control groups. The results revealed that nifedipine at dose of 500 mg/kg was the most effective and protected damage from acetaminophen toxicity.

  17. Isosorbide dinitrate and nifedipine treatment of achalasia: a clinical, manometric and radionuclide evaluation

    International Nuclear Information System (INIS)

    Gelfond, M.; Rozen, P.; Gilat, T.

    1982-01-01

    The effects of sublingual isosorbide dinitrate (5 mg) and nifedipine (20 mg) were compared in 15 patients with achalasia. The parameters examined included the manometric measurement of the lower esophageal sphincter pressure, the radionuclide assessment of esophageal emptying and the clinical response. The mean basal lower esophageal sphincter pressure fell significantly after both drugs (p less than 0.01), with a maximum fall of 63.5% 10 min after receiving isosorbide dinitrate, but by only 46.7% 30 min after nifedipine. The esophageal radionuclide test meal retention was significantly less (p less than 0.01) only after receiving isosorbide dinitrate. The drug improved initial esophageal emptying by its effect on the lower esophageal sphincter and by relieving the test meal hold-up noted to occur at the junction of the upper and midesophagus. Eight patients cleared their test meal within 10 min after isosorbide dinitrate administration while only two did so after nifedipine. Subjectively, 13 patients had their dysphagia relieved by isosorbide dinitrate and 8 by nifedipine. However, this relief was not confirmed in 4 patients by the radionuclide study and they, as well as the other 3 patients who did not respond to therapy, were referred to pneumatic dilatation. Side effects were more prominent after nitrates. Three of the patients are currently receiving nifedipine and 5 patients received isosorbide dinitrate therapy for 8-14 mo. The radionuclide test meal is currently the best way of objectively evaluating drug therapy in patients with achalasia. Isosorbide dinitrate is more effective than nifedipine in relieving their symptoms

  18. Isosorbide dinitrate and nifedipine treatment of achalasia: a clinical, manometric and radionuclide evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Gelfond, M.; Rozen, P.; Gilat, T.

    1982-11-01

    The effects of sublingual isosorbide dinitrate (5 mg) and nifedipine (20 mg) were compared in 15 patients with achalasia. The parameters examined included the manometric measurement of the lower esophageal sphincter pressure, the radionuclide assessment of esophageal emptying and the clinical response. The mean basal lower esophageal sphincter pressure fell significantly after both drugs (p less than 0.01), with a maximum fall of 63.5% 10 min after receiving isosorbide dinitrate, but by only 46.7% 30 min after nifedipine. The esophageal radionuclide test meal retention was significantly less (p less than 0.01) only after receiving isosorbide dinitrate. The drug improved initial esophageal emptying by its effect on the lower esophageal sphincter and by relieving the test meal hold-up noted to occur at the junction of the upper and midesophagus. Eight patients cleared their test meal within 10 min after isosorbide dinitrate administration while only two did so after nifedipine. Subjectively, 13 patients had their dysphagia relieved by isosorbide dinitrate and 8 by nifedipine. However, this relief was not confirmed in 4 patients by the radionuclide study and they, as well as the other 3 patients who did not respond to therapy, were referred to pneumatic dilatation. Side effects were more prominent after nitrates. Three of the patients are currently receiving nifedipine and 5 patients received isosorbide dinitrate therapy for 8-14 mo. The radionuclide test meal is currently the best way of objectively evaluating drug therapy in patients with achalasia. Isosorbide dinitrate is more effective than nifedipine in relieving their symptoms.

  19. Rapid recurrence of pulmonary hypertension following cessation of nifedipine.

    LENUS (Irish Health Repository)

    Gallagher, M M

    2012-02-03

    In a young woman with primary pulmonary hypertension, treatment with low-dose nifedipine resulted in resolution of symptoms and of tricuspid regurgitation. On withdrawal of nifedipine, symptomatic pulmonary hypertension recurred within 48 hours and was controlled by reintroduction of low-dose nifedipine.

  20. Management of preterm labor: atosiban or nifedipine?

    Science.gov (United States)

    de Heus, Roel; Mulder, Eduard J H; Visser, Gerard H A

    2010-08-09

    Preterm birth is strongly associated with neonatal death and long-term neurological morbidity. The purpose of tocolytic drug administration is to postpone threatening preterm delivery for 48 hours to allow maximal effect of antenatal corticosteroids and maternal transportation to a center with specialized neonatal care facilities. There is uncertainty about the value of atosiban (oxytocin receptor antagonist) and nifedipine (calcium channel blocker) as first-line tocolytic drugs in the management of preterm labor. For nifedipine, concerns have been raised about unproven safety, lack of placebo-controlled trials, and its off-label use. The tocolytic efficacy of atosiban has also been questioned because of a lack of reduction in neonatal morbidity. This review discusses the available evidence, the pros and cons of either drug and aims to provide information to support a balanced choice of first-line tocolytic drug: atosiban or nifedipine?

  1. Effect of nifedipine on gastric emptying in normal subjects

    International Nuclear Information System (INIS)

    Traube, M.; Lange, R.C.; McAllister, R.G.; McCallum, R.W.

    1985-01-01

    Nifedipine (N) inhibits calcium entry into smooth muscle cells and relaxes esophageal smooth muscle. The authors studied N's effect on gastric emptying of liquids and solids. Ten normal subjects underwent radionuclide (In-111-DTPA in water and Tc-99m-sulfur colloid tagged to chicken liver) emptying tests with and without 30 mg N given orally 20 min prior to meal ingestion. Peak plasma N levels were either 30 or 60 min after drug dosing and showed a 3-fold variation (low 145 ng/ml, high 434 ng/ml). Both mean N levels and integral concentration time values were twice as high as those obtained after 30 mg sublingual dosing in normals previously studied in our lab. The authors conclude that plasma N levels which are associated with significant esophageal motility effects do not change gastric emptying in normal subjects. The data also show that N levels are greater after oral than sublingual dosing of 30 mg in normal subjects

  2. Labetalol Versus Nifedipine as Antihypertensive Treatment for Chronic Hypertension in Pregnancy: A Randomized Controlled Trial.

    Science.gov (United States)

    Webster, Louise M; Myers, Jenny E; Nelson-Piercy, Catherine; Harding, Kate; Cruickshank, J Kennedy; Watt-Coote, Ingrid; Khalil, Asma; Wiesender, Cornelia; Seed, Paul T; Chappell, Lucy C

    2017-11-01

    Data from randomized controlled trials to guide antihypertensive agent choice for chronic hypertension in pregnancy are limited; this study aimed to compare labetalol and nifedipine, additionally assessing the impact of ethnicity on treatment efficacy. Pregnant women with chronic hypertension (12 +0 -27 +6 weeks' gestation) were enrolled at 4 UK centers (August 2014 to October 2015). Open-label first-line antihypertensive treatment was randomly assigned: labetalol- (200-1800 mg/d) or nifedipine-modified release (20-80 mg/d). Analysis included 112 women (98%) who completed the study (labetalol n=55, nifedipine n=57). Maximum blood pressure after randomization was 161/101 mm Hg with labetalol versus 163/105 mm Hg with nifedipine (mean difference systolic: 1.2 mm Hg [-4.9 to 7.2 mm Hg], diastolic: 3.3 mm Hg [-0.6 to 7.3 mm Hg]). Mean blood pressure was 134/84 mm Hg with labetalol and 134/85 mm Hg with nifedipine (mean difference systolic: 0.3 mm Hg [-2.8 to 3.4 mm Hg], and diastolic: -1.9 mm Hg [-4.1 to 0.3 mm Hg]). Nifedipine use was associated with a 7.4-mm Hg reduction (-14.4 to -0.4 mm Hg) in central aortic pressure, measured by pulse wave analysis. No difference in treatment effect was observed in black women (n=63), but a mean 4 mm Hg reduction (-6.6 to -0.8 mm Hg; P =0.015) in brachial diastolic blood pressure was observed with labetalol compared with nifedipine in non-black women (n=49). Labetalol and nifedipine control mean blood pressure to target in pregnant women with chronic hypertension. This study provides support for a larger definitive trial scrutinizing the benefits and side effects of first-line antihypertensive treatment. URL: https://www.isrctn.com. Unique identifier: ISRCTN40973936. © 2017 American Heart Association, Inc.

  3. Anticonvulsant and antiarrhythmic effects of nifedipine in rats prone to audiogenic seizures

    International Nuclear Information System (INIS)

    Damasceno, D.D.; Ferreira, A.J.; Doretto, M.C.; Almeida, A.P.

    2012-01-01

    Calcium ion participates in the regulation of neural transmission and the presynaptic release of neurotransmitters. It is also involved in epileptic events, cardiac arrhythmias and abnormal conduction of stimuli. The purpose of the present study was to evaluate the effects of nifedipine, a calcium channel blocker, on epileptic seizures and on reperfusion arrhythmias in rats prone to audiogenic epileptic seizures (Wistar audiogenic rats, WAR) and in normal Wistar rats (N = 6/group). The seizure severity index was applied after an intraperitoneal injection of 20 or 40 mg/kg nifedipine (N20 and N40 groups, respectively). The Langendorff technique was used to analyze cardiac function, as well as the incidence and severity of the reperfusion arrhythmias after ligature and release of the left coronary artery in rats treated or not with nifedipine. We found that nifedipine treatment decreased seizure severity (0.94 ± 0.02 for WAR; 0.70 ± 0.10 for WAR + N20; 0.47 ± 0.08 for WAR + N40) and increased the latent period (13 ± 2 s for WAR; 35 ± 10 s for WAR + N20; 48 ± 7 s for WAR + N40) for the development of seizures in WAR. Furthermore, the incidence and severity of the reperfusion arrhythmias were lower in WAR and normal Wistar rats injected with nifedipine. In WAR, these effects were mediated, at least in part, by a decrease in heart rate. Thus, our results indicate that nifedipine may be considered to be a potential adjuvant drug for epilepsy treatment, especially in those cases associated with cardiac rhythm abnormalities

  4. Anticonvulsant and antiarrhythmic effects of nifedipine in rats prone to audiogenic seizures

    Energy Technology Data Exchange (ETDEWEB)

    Damasceno, D.D. [Departamento de Desenvolvimento Educacional,Instituto Federal de Educação, Ciência e Tecnologia do Sudeste de Minas Gerais, Barbacena, MG (Brazil); Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Ferreira, A.J. [Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Doretto, M.C.; Almeida, A.P. [Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil)

    2012-07-20

    Calcium ion participates in the regulation of neural transmission and the presynaptic release of neurotransmitters. It is also involved in epileptic events, cardiac arrhythmias and abnormal conduction of stimuli. The purpose of the present study was to evaluate the effects of nifedipine, a calcium channel blocker, on epileptic seizures and on reperfusion arrhythmias in rats prone to audiogenic epileptic seizures (Wistar audiogenic rats, WAR) and in normal Wistar rats (N = 6/group). The seizure severity index was applied after an intraperitoneal injection of 20 or 40 mg/kg nifedipine (N20 and N40 groups, respectively). The Langendorff technique was used to analyze cardiac function, as well as the incidence and severity of the reperfusion arrhythmias after ligature and release of the left coronary artery in rats treated or not with nifedipine. We found that nifedipine treatment decreased seizure severity (0.94 ± 0.02 for WAR; 0.70 ± 0.10 for WAR + N20; 0.47 ± 0.08 for WAR + N40) and increased the latent period (13 ± 2 s for WAR; 35 ± 10 s for WAR + N20; 48 ± 7 s for WAR + N40) for the development of seizures in WAR. Furthermore, the incidence and severity of the reperfusion arrhythmias were lower in WAR and normal Wistar rats injected with nifedipine. In WAR, these effects were mediated, at least in part, by a decrease in heart rate. Thus, our results indicate that nifedipine may be considered to be a potential adjuvant drug for epilepsy treatment, especially in those cases associated with cardiac rhythm abnormalities.

  5. Anticonvulsant and antiarrhythmic effects of nifedipine in rats prone to audiogenic seizures

    Directory of Open Access Journals (Sweden)

    D.D. Damasceno

    2012-11-01

    Full Text Available Calcium ion participates in the regulation of neural transmission and the presynaptic release of neurotransmitters. It is also involved in epileptic events, cardiac arrhythmias and abnormal conduction of stimuli. The purpose of the present study was to evaluate the effects of nifedipine, a calcium channel blocker, on epileptic seizures and on reperfusion arrhythmias in rats prone to audiogenic epileptic seizures (Wistar audiogenic rats, WAR and in normal Wistar rats (N = 6/group. The seizure severity index was applied after an intraperitoneal injection of 20 or 40 mg/kg nifedipine (N20 and N40 groups, respectively. The Langendorff technique was used to analyze cardiac function, as well as the incidence and severity of the reperfusion arrhythmias after ligature and release of the left coronary artery in rats treated or not with nifedipine. We found that nifedipine treatment decreased seizure severity (0.94 ± 0.02 for WAR; 0.70 ± 0.10 for WAR + N20; 0.47 ± 0.08 for WAR + N40 and increased the latent period (13 ± 2 s for WAR; 35 ± 10 s for WAR + N20; 48 ± 7 s for WAR + N40 for the development of seizures in WAR. Furthermore, the incidence and severity of the reperfusion arrhythmias were lower in WAR and normal Wistar rats injected with nifedipine. In WAR, these effects were mediated, at least in part, by a decrease in heart rate. Thus, our results indicate that nifedipine may be considered to be a potential adjuvant drug for epilepsy treatment, especially in those cases associated with cardiac rhythm abnormalities.

  6. Management of preterm labor: atosiban or nifedipine?

    Directory of Open Access Journals (Sweden)

    Roel de Heus

    2010-05-01

    Full Text Available Roel de Heus, Eduard J H Mulder, Gerard H A VisserDepartment of Woman and Baby, University Medical Centre Utrecht, The NetherlandsAbstract: Preterm birth is strongly associated with neonatal death and long-term neurological morbidity. The purpose of tocolytic drug administration is to postpone threatening preterm delivery for 48 hours to allow maximal effect of antenatal corticosteroids and maternal transportation to a center with specialized neonatal care facilities. There is uncertainty about the value of atosiban (oxytocin receptor antagonist and nifedipine (calcium channel blocker as first-line tocolytic drugs in the management of preterm labor. For nifedipine, concerns have been raised about unproven safety, lack of placebo-controlled trials, and its off-label use. The tocolytic efficacy of atosiban has also been questioned because of a lack of reduction in neonatal morbidity. This review discusses the available evidence, the pros and cons of either drug and aims to provide information to support a balanced choice of first-line tocolytic drug: atosiban or nifedipine?Keywords: atosiban, oxytocin receptor antagonist, nifedipine, calcium channel blocker, preterm birth, tocolytic drugs, preterm labor

  7. Comparative effects of imipramine, sertraline, nifedipine, furosemide ...

    African Journals Online (AJOL)

    The objective of the study was to evaluate the comparative effects of imipramine, sertraline, nifedipine, furosemide and bumetanide on ingestive behavior in rodents. Twelve groups (with six in each group) of male mice (25 to 35 g) were used in the experiments. They were housed in labelled plastic cages in the departmental ...

  8. Nifedipine as a uterine relaxant for external cephalic version: a randomized controlled trial.

    Science.gov (United States)

    Kok, Marjolein; Bais, Joke M; van Lith, Jan M; Papatsonis, Dimitri M; Kleiverda, Gunilla; Hanny, Dahrs; Doornbos, Johannes P; Mol, Ben W; van der Post, Joris A

    2008-08-01

    To estimate the effectiveness of nifedipine as a uterine relaxant during external cephalic version to correct breech presentation. In this randomized, double-blind, placebo-controlled trial, women with a singleton fetus in breech presentation and a gestational age of 36 weeks or more were eligible for enrollment. Participating women received two doses of either nifedipine 10 mg or placebo, 30 and 15 minutes before the external cephalic version attempt. The primary outcome was a cephalic-presenting fetus immediately after the procedure. Secondary outcome measures were cephalic presentation at delivery, mode of delivery, and adverse events. A sample size of 292 was calculated to provide 80% power to detect a 17% improvement of the external cephalic version success rate, assuming a placebo group rate of 40% and alpha of .05. Outcome data for 310 of 320 randomly assigned participants revealed no significant difference in external cephalic version success rates between treatment (42%) and control group (37%) (relative risk 1.1, 95%; 95% confidence interval 0.85-1.5). The cesarean delivery rate was 51% in the treatment group and 46% in the control group (relative risk 1.1, 95% confidence interval 0.88-1.4). Nifedipine did not significantly improve the success of external cephalic version. Future use of nifedipine to improve the outcome of external cephalic version should be limited to large clinical trials.

  9. Metabolic effect of combined telmisartan and nifedipine CR therapy in patients with essential hypertension

    Directory of Open Access Journals (Sweden)

    Shimizu Y

    2012-09-01

    Full Text Available Yuji Shimizu,1,4 Fumiyasu Yamasaki,4 Takashi Furuno,1,4 Toru Kubo,1 Takayuki Sato,3,4 Yoshinori Doi,1 Tetsuro Sugiura21Medicine and Geriatrics, 2Clinical Laboratory, 3Cardiovascular Control, Kochi Medical, School, Nankoku, Japan; 4Section of Cardiology, Inoue Hospital, Takaoka, JapanBackground: In addition to exerting a blood pressure (BP-lowering effect, telmisartan produces favorable metabolic effects via peroxisome proliferator-activated receptor γ activation. While a combination of telmisartan and a calcium channel blocker is often used to achieve a target BP level, the metabolic effects of this drug combination remain unclear. Therefore, this study evaluated the metabolic effects of telmisartan plus nifedipine controlled release (CR therapy, in hypertensive patients without metabolic disease.Methods: Sixteen patients with essential hypertension, who had not undergone antihypertensive therapy in the previous 6 months, were studied. Patients were initiated on telmisartan (40 mg/day. If their office BP was not reduced to 140/90 mmHg after 6 weeks, nifedipine CR (20–40 mg per day was added for 18 weeks. The other patients whose BP had achieved the target of 140/90 mmHg, continued only telmisartan.Results: Telmisartan reduced BP (174 ± 13/92 ± 10 to 143 ± 22/78 ± 11 mmHg; P < 0.01 at 6 weeks in 16 patients, but eight patients did not achieve target BP levels and required addition of nifedipine. Telmisartan also resulted in a reduction in the homeostatic model assessment of insulin resistance (HOMA-IR (1.30 ± 0.65 to 1.10 ± 0.42; P < 0.05 at 6 weeks, but did not affect adiponectin or leptin levels. Addition of nifedipine (n = 8 resulted in a reduction in BP (158 ± 18/80 ± 13 to 131 ± 8/73 ± 13 mmHg; P < 0.01 at 18 weeks, but did not affect the HOMA-IR (1.10 ± 0.40 to 1.02 ± 0.56; ns. In patients who did not require addition of nifedipine (n = 8, BP levels remained nearly identical at 18 weeks (127 ± 13/73 ± 9 to 128 ± 13/68 ± 8

  10. Investigation of bioequivalence of a new fixed-dose combination of nifedipine and candesartan with the corresponding loose combination as well as the drug-drug interaction potential between both drugs under fasting conditions.

    Science.gov (United States)

    Brendel, Erich; Weimann, Boris; Dietrich, Hartmut; Froede, Christoph; Thomas, Dirk

    2013-09-01

    To determine the bioequivalence of a nifedipine and candesartan fixed-dose combination (FDC) with the corresponding loose combination, and to investigate the pharmacokinetic drug-drug interaction potential between both drugs. 49 healthy, white, male subjects received: 60 mg nifedipine and 32 mg candesartan FDC, the loose combination of 60 mg nifedipine GITS and 32 mg candesartan, 60 mg nifedipine GITS alone, or 32 mg candesartan alone in a randomized, non-blinded, 4-period, 4-way crossover design with each dosing following overnight fasting. Treatment periods were separated by washout periods of ≥ 5 days. Plasma samples were collected for 48 hours after dosing and assayed using a validated LC-MS/MS method. Bioequivalence between the FDC and the loose combination as well as the impact of combined treatment with both drugs on candesartan pharmacokinetics was evaluated in 47 subjects, while the corresponding impact of treatment with both drugs on nifedipine pharmacokinetics was assessed in 46 patients. For AUC(0-tlast) and Cmax the 90% confidence intervals (CIs) for the ratios of the FDC vs. the corresponding loose combination were within the acceptance range for bioequivalence of 80 - 125%. When comparing AUC(0-tlast) and Cmax of nifedipine and candesartan after dosing with the loose combination vs. each drug alone, the 90% CIs remained within the range of 80 - 125% indicating the absence of a clinically relevant pharmacokinetic drug-drug interaction. Nifedipine and candesartan as well as the combinations were well tolerated. The FDC containing 60 mg nifedipine and 32 mg candesartan was bioequivalent to the corresponding loose combination following single oral doses under fasting conditions. No clinically relevant pharmacokinetic drug-drug interaction between nifedipine and candesartan was observed.

  11. Nifedipine promotes the proliferation and migration of breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Dong-Qing Guo

    Full Text Available Nifedipine is widely used as a calcium channel blocker (CCB to treat angina and hypertension,but it is controversial with respect the risk of stimulation of cancers. In this study, we demonstrated that nifedipine promoted the proliferation and migration of breast cancer cells both invivo and invitro. However, verapamil, another calcium channel blocker, didn't exert the similar effects. Nifedipine and high concentration KCl failed to alter the [Ca2+]i in MDA-MB-231 cells, suggesting that such nifedipine effect was not related with calcium channel. Moreover, nifedipine decreased miRNA-524-5p, resulting in the up-regulation of brain protein I3 (BRI3. Erk pathway was consequently activated and led to the proliferation and migration of breast cancer cells. Silencing BRI3 reversed the promoting effect of nifedipine on the breast cancer. In a summary, nifedipine stimulated the proliferation and migration of breast cancer cells via the axis of miRNA-524-5p-BRI3-Erk pathway independently of its calcium channel-blocking activity. Our findings highlight that nifedipine but not verapamil is conducive for breast cancer growth and metastasis, urging that the caution should be taken in clinic to prescribe nifedipine to women who suffering both hypertension and breast cancer, and hypertension with a tendency in breast cancers.

  12. Nifedipine treatment reduces resting calcium concentration, oxidative and apoptotic gene expression, and improves muscle function in dystrophic mdx mice.

    Directory of Open Access Journals (Sweden)

    Francisco Altamirano

    Full Text Available Duchenne Muscular Dystrophy (DMD is a recessive X-linked genetic disease, caused by mutations in the gene encoding dystrophin. DMD is characterized in humans and in mdx mice by a severe and progressive destruction of muscle fibers, inflammation, oxidative/nitrosative stress, and cell death. In mdx muscle fibers, we have shown that basal ATP release is increased and that extracellular ATP stimulation is pro-apoptotic. In normal fibers, depolarization-induced ATP release is blocked by nifedipine, leading us to study the potential therapeutic effect of nifedipine in mdx muscles and its relation with extracellular ATP signaling. Acute exposure to nifedipine (10 µM decreased [Ca(2+]r, NF-κB activity and iNOS expression in mdx myotubes. In addition, 6-week-old mdx mice were treated with daily intraperitoneal injections of nifedipine, 1 mg/Kg for 1 week. This treatment lowered the [Ca(2+]r measured in vivo in the mdx vastus lateralis. We demonstrated that extracellular ATP levels were higher in adult mdx flexor digitorum brevis (FDB fibers and can be significantly reduced after 1 week of treatment with nifedipine. Interestingly, acute treatment of mdx FDB fibers with apyrase, an enzyme that completely degrades extracellular ATP to AMP, reduced [Ca(2+]r to a similar extent as was seen in FDB fibers after 1-week of nifedipine treatment. Moreover, we demonstrated that nifedipine treatment reduced mRNA levels of pro-oxidative/nitrosative (iNOS and gp91(phox/p47(phox NOX2 subunits and pro-apoptotic (Bax genes in mdx diaphragm muscles and lowered serum creatine kinase (CK levels. In addition, nifedipine treatment increased muscle strength assessed by the inverted grip-hanging test and exercise tolerance measured with forced swimming test in mdx mice. We hypothesize that nifedipine reduces basal ATP release, thereby decreasing purinergic receptor activation, which in turn reduces [Ca(2+]r in mdx skeletal muscle cells. The results in this work open new

  13. Safety of nifedipine GITS in stable angina: The ACTION trial

    NARCIS (Netherlands)

    P. Poole-Wilson (Philip); B.A. Kirwan (Bridget Anne); Z. Vokó (Zoltán); S. de Brouwer (Sophie); F.J. van Dalen (Frederik); J. Lubsen (Jacob)

    2006-01-01

    textabstractAim: We describe the safety profile of nifedipine GITS as assessed from adverse events reported in the ACTION trial in which 7,665 patients with stable, symptomatic coronary artery disease were randomly assigned nifedipine GITS or placebo and followed for a mean of 4.9 years. Methods:

  14. Effect of nifedipine on gastric emptying in normal subjects

    Energy Technology Data Exchange (ETDEWEB)

    Traube, M.; Lange, R.C.; McAllister, R.G.; McCallum, R.W.

    1985-05-01

    Nifedipine (N) inhibits calcium entry into smooth muscle cells and relaxes esophageal smooth muscle. The authors studied N's effect on gastric emptying of liquids and solids. Ten normal subjects underwent radionuclide (In-111-DTPA in water and Tc-99m-sulfur colloid tagged to chicken liver) emptying tests with and without 30 mg N given orally 20 min prior to meal ingestion. Peak plasma N levels were either 30 or 60 min after drug dosing and showed a 3-fold variation (low 145 ng/ml, high 434 ng/ml). Both mean N levels and integral concentration time values were twice as high as those obtained after 30 mg sublingual dosing in normals previously studied in our lab. The authors conclude that plasma N levels which are associated with significant esophageal motility effects do not change gastric emptying in normal subjects. The data also show that N levels are greater after oral than sublingual dosing of 30 mg in normal subjects.

  15. Effect of Nifedipine on Reproductive Functions in Male Rats ...

    African Journals Online (AJOL)

    Effect of Nifedipine on Reproductive Functions in Male Rats. ... Background: After life itself, fertility is probably the most highly prized human possession. ... Animals in Group 3 were allowed another 30 days after drug withdrawal for recovery.

  16. Development of Sustained-Release Microbeads of Nifedipine and In ...

    African Journals Online (AJOL)

    Methods: Nifedipine microbeads were prepared using sodium alginate and pectin in different ratios by ionic-gelation method. ... Oral sustained release dosage forms provide ... Stability in .... 37oC) in a USP XXII apparatus (Pharma Test,.

  17. Photoreactivity of nifedipine in vitro and in vivo.

    Science.gov (United States)

    de Vries, H; Beijersbergen van Henegouwen, G M

    1998-06-01

    Side effects of nitroaromatics used as drugs are often assumed to be caused by incomplete enzymatic reduction of the nitro group. However, photoactivation, although usually not considered as a cause of the toxic effects of nitroaromatics, can play a considerable role. Nifedipine, a nitroaromatic as well, is an important drug used in the treatment of myocardial ischaemia and hypertension. It is extremely sensitive to ultraviolet and visible light up to 450 nm and forms a nitroso derivative in vitro. In the present study it is shown that the nitroso compound is a short-lived intermediate in blood and plasma. It reacts with other constituents to form a stable lactam. In vivo, this lactam proves to be rapidly clear from the blood of rats and is excreted almost quantitatively via the bile. The first photoproduct of nifedipine, nitroso nifedipine, is shown to be converted into the lactam mentioned. Beside the lactam, two other products, which are considered to be derivatives of the lactam, are found. One of these two products is also found in the bile of a rat that was exposed to UVA light after intravenous nifedipine administration. This shows that in an in vivo situation, photoproducts can reach organs other than those exposed to the light. In vitro about 45 to 50% of the original amount of nifedipine is not recovered after exposure of nifedipine to UVA in the presence of bovine serum albumin or after incubation of nitroso nifedipine with bovine serum albumin in the dark. As complex binding of nifedipine of plasma proteins is high, the latter finding may have important implications for the situation in vivo.

  18. Beneficial effect of low dose Amlodipine vs Nifedipine on serum cholesterol profile of rabbits receiving standard diet.

    Directory of Open Access Journals (Sweden)

    Bavane DS, Rajesh CS, Gurudatta Moharir, Bharatha Ambadasu

    2013-01-01

    Full Text Available To investigate the effect of low dose amlodipine v/s nifedipine on serum cholesterol profile of rabbits receiving standard diet. Methods: Fourty Newzealand rabbits were selected for the study. Their cholesterol profile was estimated at the beginning of the study. Rabbits were grouped into 4 groups receiving standard diet (control group, standard diet + vehicle propylene glycol, standard diet + nifedipine dissolved in propylene glycol and standard diet + amlodipine dissolved in propylene glycol. Along with standard diet they were treated with respective drugs for ten weeks. At the end of ten weeks serum cholesterol profile was estimated. Results: The cholesterol profile was estimated at the beginning and at the end of ten weeks. Total cholesterol in the amlodipine group decreased from 97±4.06 mg/dl to 90±4.2 mg/dl and HDL-Cholesterol increased from 32.01±4.40 mg/dl to 37±4.60 mg/dl after 10 week treatment but these changes were not significant. LDL cholesterol decreased significantly in rabbits with low dose of amlodipine from 55.42±3.32 mg/dl to 32.40±3.22 mg/dl and. In the nifedipine group there was a slight increase in total cholesterol from 102.49±5.16 mg/dl to 106±5.39 mg/dl, HDL cholesterol from 34.10±2.80 to 35.16±2.82 mg/dl and LDL cholesterol also increased from 56.20±2.20 mg/dl to 59.00±2.20 mg/dl after 10 week treatment. Conclusion: The study shows amlodipine produces favorable alterations in serum cholesterol profile

  19. Randomized double-blind comparison of metoprolol, nifedipine, and their combination in chronic stable angina

    DEFF Research Database (Denmark)

    Egstrup, K

    1988-01-01

    In a randomized double-blind study, treatment with either metoprolol, nifedipine, or their combination was compared for effects on ischemic variables and heart rate obtained during ambulatory monitoring in 42 patients with chronic stable angina. All patients had severe chronic stable angina...... could be detected during nifedipine monotherapy. It is concluded that metoprolol monotherapy, as well as its combination with nifedipine, effectively reduces total ischemic activity compared with placebo and nifedipine monotherapy. Control of ischemic activity in chronic stable angina may have...

  20. Effect of concomitant administration of nifedipine and tacrolimus on the development of gingival overgrowth in rats

    Directory of Open Access Journals (Sweden)

    Sheng-Yi Chen

    2015-03-01

    Conclusion: Gingival overgrowth could be induced either by nifedipine or by tacrolimus, although the extent of gingival overgrowth induced by tacrolimus would be less than that by nifedipine. However, a concomitant administration of nifedipine and tacrolimus did not aggravate the induced gingival overgrowth.

  1. Studying the Impact of Modified Saccharides on the Molecular Dynamics and Crystallization Tendencies of Model API Nifedipine.

    Science.gov (United States)

    Kaminska, E; Tarnacka, M; Wlodarczyk, P; Jurkiewicz, K; Kolodziejczyk, K; Dulski, M; Haznar-Garbacz, D; Hawelek, L; Kaminski, K; Wlodarczyk, A; Paluch, M

    2015-08-03

    Molecular dynamics of pure nifedipine and its solid dispersions with modified carbohydrates as well as the crystallization kinetics of active pharmaceutical ingredient (API) above and below the glass transition temperature were studied in detail by means of broadband dielectric spectroscopy (BDS), differential scanning calorimetry (DSC), and X-ray diffraction method. It was found that the activation barrier of crystallization increases in molecular dispersions composed of acetylated disaccharides, whereas it slightly decreases in those consisting of modified monocarbohydrates for the experiments carried out above the glass transition temperature. As shown by molecular dynamics simulations it can be related to the strength, character, and structure of intermolecular interactions between API and saccharides, which vary dependently on the excipient. Long-term physical stability studies showed that, in solid dispersions consisting of acetylated maltose and acetylated sucrose, the crystallization of nifedipine is dramatically slowed down, although it is still observable for a low concentration of excipients. With increasing content of modified carbohydrates, the crystallization of API becomes completely suppressed. This is most likely due to additional barriers relating to the intermolecular interactions and diffusion of nifedipine that must be overcome to trigger the crystallization process.

  2. Development of coated nifedipine dry elixir as a long acting oral delivery with bioavailability enhancement.

    Science.gov (United States)

    Choi, Jae-Yoon; Jin, Su-Eon; Park, Youmie; Lee, Hyo-Jong; Park, Yohan; Maeng, Han-Joo; Kim, Chong-Kook

    2011-10-01

    To develop the long acting nifedipine oral delivery with bioavailability enhancement, a nifedipine dry elixir (NDE) containing nifedipine ethanol solution in dextrin shell was prepared using a spray-dryer, and then coated nifedipine dry elixir (CNDE) was prepared by coating NDE with Eudragit acrylic resin. The physical characteristics and bioavailability of NDE and CNDE were evaluated, and then compared to those of nifedipine powder. NDE and CNDE, which were spherical in shape, had about 6.64 and 8.68-8.75 μm of geometric mean diameters, respectively. The amount of nifedipine dissolved from NDE for 60 min increased about 7- and 40-fold compared to nifedipine powder in pH 1.2 simulated gastric fluid and pH 6.8 simulated intestinal fluid, respectively. Nifedipine released from CNDE was retarded in both dissolution media compared with that from NDE. After oral administration of NDE, the C(max) and AUC(0→8h) of nifedipine in rat increased about 13- and 7-fold, respectively, and the Tmax of nifedipine was reduced significantly compared with those after oral administration of nifedipine powder alone. The AUC(0→8h) and T(max) of nifedipine in CNDE increased markedly and the C(max) of nifedipine in CNDE was significantly reduced compared to those in NDE. It is concluded that CNDE, which could lower the initial burst-out plasma concentration and maintain the plasma level of nifedipine over a longer period with bioavailability enhancement, might be one of potential alternatives to the marketed long acting oral delivery system for nifedipine.

  3. Effect of nifedipine, imipramine and sertraline on the antidepressant ...

    African Journals Online (AJOL)

    The objective of the study was to determine the effect of nifedipine, imipramine and sertraline on the acute and long-term antidepressant-like responses of furosemide in the forced swim (FST) and tail suspension (TST) tests in mice. Groups of mice of six in each group were treated for 30 days with Tween 80, furosemide (10 ...

  4. Safety of the Up-titration of Nifedipine GITS and Valsartan or Low-dose Combination in Uncontrolled Hypertension: the FOCUS Study.

    Science.gov (United States)

    Park, Jeong Bae; Shin, Joon-Han; Kim, Dong-Soo; Youn, Ho-Joong; Park, Seung Woo; Shim, Wan Joo; Park, Chang Gyu; Kim, Dong-Woon; Lee, Hae-Young; Choi, Dong-Ju; Rim, Se-Joong; Lee, Sung-Yun; Kim, Ju-Han

    2016-04-01

    Doubling the dose of antihypertensive drugs is necessary to manage hypertension in patients whose disease is uncontrolled. However, this strategy can result in safety issues. This study compared the safety and efficacy of up-titration of the nifedipine gastrointestinal therapeutic system (GITS) with up-titration of valsartan monotherapy; these were also compared with low-dose combinations of the two therapies. This prospective, open-label, randomized, active-controlled, multicenter study lasted 8 weeks. If patients did not meet the target blood pressure (BP) after 4 weeks of treatment with low-dose monotherapy, they were randomized to up-titration of the nifedipine GITS dose from 30 mg (N30) to 60 mg or valsartan from 80 mg to 160 mg or they were randomized to receive a low-dose combination of N30 and valsartan 80 mg for another 4 weeks. BP variability was assessed by using the SD or the %CV of the short-term BP measured at clinic. Of the 391 patients (20~70 years with stage II or higher hypertension) screened for study inclusion, 362 patients who had 3 BP measurements were enrolled. The reduction in the mean systolic/diastolic BP from baseline to week 4 was similar in both low-dose monotherapy groups with either N30 or valsartan 80 mg. BP variability (SD) was unchanged with either therapy, but the %CV was slightly increased in the N30 group. There was no significant difference in BP variability either in SD or %CV between responders and nonresponders to each monotherapy despite the significant difference in the mean BP changes. The up-titration effect of nifedipine GTS from 30 to 60 mg exhibited an additional BP reduction, but this effect was not shown in the up-titration of valsartan from 80 to 160 mg. Although the difference in BP was obvious between high-dose nifedipine GTS and valsartan, the BP variability was unchanged between the 2 drugs and was similar to the low-dose combinations. There was a low rate of adverse events in all treatment groups. In addition

  5. A STUDY OF ANTICONVULSANT EFFECT OF FLUNARIZINE AND NIFEDIPINE IN COMPARISON WITH SODIUM VALPROATE ON MES AND PTZ MODELS OF EPILEPSY IN ALBINO RATS

    Directory of Open Access Journals (Sweden)

    Umesh G.

    2015-03-01

    Full Text Available BACKGROUND : CA +2 ions are involved in initiation as well as spread of seizures. Hence current study was undertaken to evaluate the anticonvulsant effect of calcium channel blockers flunarizine, nifedipine and compare their efficacy with that of sodium valproate, the broad spectrum anticonvulsant in MES and PTZ induced seizures in albino rats. MATERIALS AND METHODS : Albino rats were treated with nife dipine 2.5mg/kg, 5mg/kg, flunarizine 7.5mg/kg,15mg/kg and sodium valproate 250mg/kg bodyweight intraperitoneally and the effects were observed in MES and PTZ models of epilepsy. The parameters observed in MES model was , duration of HLTE phase . Convulsive p hase, and post ictal depressive phase. In PTZ model duration of seizure latency, duration of convulsion , and duration post ictal depression were observed. RESULTS : our study demonstrated that both calcium channel blockers afford protection against convulsi ons induced in both models, and flunarizine affords higher degree of protection than nifedipine, with its efficacy almost approaching that of sodium valproate. CONCLUSION : Flunarizine has significant, while nifedipine has moderate degree of anticonvulsant activity as compared to sodium valproate

  6. Thermal methods for evaluating polymorphic transitions in nifedipine

    International Nuclear Information System (INIS)

    Grooff, D.; De Villiers, M.M.; Liebenberg, W.

    2007-01-01

    The thermal behaviour of nifedipine was studied with the view to understand the various phase transitions between its polymorphs. The focus was on polymorph identification, accompanying morphological changes during crystallization and the nature of the phase transformations. These features were compared to the complexity of the crystallization mechanisms, studied by dynamic differential scanning calorimetry (DSC) heating techniques. DSC, thermogravimetry (TG) established the temperature limits for preparation of amorphous nifedipine from the melt. DSC studies identified that metastable form B, melting point ∼163 deg. C, was enantiotropically related to a third modification, form C, which existed at lower temperatures. Form C converted endothermically to form B at ∼56 deg. C on heating and was shown by hot stage microscopy (HSM) to be accompanied by morphological changes. Modulated temperature differential scanning calorimetry (MTDSC) showed discontinuities in the reversing heat flow signal during crystallization of amorphous nifedipine (from ∼92 deg. C) to form B, which suggested that a number of polymorphs may nucleate from the melt prior to form B formation. Identification of the number of nifedipine polymorphs included the use of combined DSC-powder X-ray diffraction (PXRD) and variable temperature powder X-ray diffraction (VTPXRD). The crystallization kinetics studied by dynamic DSC heating techniques followed by analysis using the Friedman isoconversion method where values of activation energy (E) and frequency factor (A) were estimated as a function of alpha or extent of conversion (α). The variations in E with α, from 0.05 to 0.9, for the amorphous to form B conversion could indicate the formation of intermediate polymorphs prior to form B. The form B to form A conversion showed a constancy in E on kinetic analysis from α 0.05 to 0.9, which suggested that a constant crystallization mechanism operated during formation of the thermodynamically stable

  7. Effects of nifedipine on anorectal smooth muscle in vitro.

    Science.gov (United States)

    Cook, T A; Brading, A F; Mortensen, N J

    1999-06-01

    Glyceryl trinitrate reduces anal resting pressure and aids the healing of anal fissures. However, some patients develop tachyphylaxis and the fissure fails to heal, suggesting that other agents are needed. This study assesses the effects of nifedipine (a calcium channel antagonist) in modulating resting tone and agonist-induced contractions in human internal anal sphincter (IAS) and rectal circular muscle. Smooth muscle strips from the IAS and rectal circular muscle from ten patients undergoing surgical resection were mounted for isometric tension recording in a superfusion organ bath. The effects of noradrenaline and carbachol were assessed in the presence of various perfusates. LAS strips developed tone and spontaneous activity. Noradrenaline produced dose-dependent contractions. In calcium-free Krebs solution, tone and activity were abolished and no contractions were elicited in response to noradrenaline. Nifedipine also abolished tone and spontaneous activity, but contractions to noradrenaline were only slightly attenuated. In contrast, rectal smooth muscle strips developed spontaneous activity but no resting tone and contracted in response to carbachol. In calcium-free Krebs solution, the spontaneous activity and carbachol contractions were abolished. Addition of nifedipine to the perfusate abolished spontaneous activity and greatly reduced contractions. These data suggest that spontaneous activity and resting tone are dependent on extracellular calcium and flux across the cells. Agonist-induced contraction in the IAS is attributable mainly to the release of calcium from intracellular stores, whereas rectal circular smooth muscle depends principally on extracellular calcium entering the cell for contraction. The attenuation of contractions in both tissues and the abolition of resting tone in the IAS suggest that nifedipine may be useful in the management of patients with anorectal disorders.

  8. Better microvascular function on long-term treatment with lisinopril than with nifedipine in renal transplant recipients.

    Science.gov (United States)

    Asberg, A; Midtvedt, K; Vassbotn, T; Hartmann, A

    2001-07-01

    The prevalence of hypertension in renal transplant recipients is high but the pathophysiology is poorly defined. Impaired endothelial function may be a factor of major importance. The present study addresses the effects of long-term treatment with either lisinopril or slow-release nifedipine on microvascular function and plasma endothelin in renal transplant recipients on cyclosporin A (CsA). Seventy-five hypertensive renal transplant recipients were double-blind randomized to receive slow-release nifedipine (NIF, n=40) or lisinopril (LIS, n=35). Ten normotensive, age-matched recipients served as controls. All patients received CsA-based immunosuppressive therapy including prednisolone and azathioprine. Microvascular function was assessed in the forearm skin vasculature, using laser Doppler flowmetry in combination with post-occlusive reactive hyperaemia and endothelial-dependent function during local acetylcholine (ACh) stimulation. The analysis of microvascular function (AUC(rh)) showed that nifedipine-treated patients had significantly lower responses compared with lisinopril-treated patients (20+/-17 and 43+/-20 AU x min respectively, P=0.0016). Endothelial function was borderline significantly lower in the NIF group compared with the LIS group (640+/-345 and 817+/-404 AU x min respectively, P=0.056). The responses in the LIS group were comparable with those in non-hypertensive controls (AUC(rh) was 37+/-16 and AUC(ACh) was 994+/-566 AU x min). Plasma endothelin-1 concentrations were significantly higher in the NIF group compared with the LIS group (0.44+/-0.19 vs. 0.34+/-0.10 fmol/ml respectively, P=0.048), and were 0.29+/-0.09 fmol/ml in the control patients. AUC(ACh) was associated with plasma endothelin-1 (P=0.0053), while AUC(rh) was not (P=0.080). The study indicates that long-term treatment with lisinopril, when compared with nifedipine, yields a more beneficial effect on microvascular function in hypertensive renal transplant recipients on CsA. The

  9. PLA/CS/Nifedipine Nanocomposite Films: Properties and the In Vitro Release of Nifedipine

    Science.gov (United States)

    Trang, Nguyen Thi Thu; Chinh, Nguyen Thuy; Giang, Nguyen Vu; Thanh, Dinh Thi Mai; Lam, Tran Dai; Hoang, Thai

    2016-07-01

    The polylactic acid (PLA)/chitosan (CS) films containing a drug, nifedipine (NIF), in the presence of polyethylene oxide (PEO) as a compatibilizer were prepared by the solution method. This method has not been used to form films containing four components (PLA, CS, NIF, PEO) up to now. The CS, PEO, and NIF contents are 25 wt.%, 6-8 wt.%, and 10-50 wt.% in comparison with PLA weight, respectively. Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), and field emission scanning electron microscopy (FESEM) were used to characterize the interactions, properties, and morphology of the PLA/CS/PEO/NIF films. The FTIR, TGA, and DSC results show that NIF carried by PLA/CS/PEO films and PLA, CS, NIF had better interaction and were more compatible when using PEO. The surface morphology of PLA/CS/PEO/NIF films was similar to that of PLA/CS/PEO films. Moreover, this was the first time drug loading and NIF release content from PLA/CS/PEO films were determined by the ultraviolet-visible (UV-Vis) spectroscopy method. The drug loading of PLA/CS/PEO/NIF films was from 80.99% to 93.61%. The in vitro NIF release studies were carried out in pH 2, 6.8, and 7.4 solutions corresponding to the pH of stomach, colon, and duodenum regions in the human body, respectively. The NIF release content in different pH solutions is in the order: pH 2 > pH 6.8 > pH 7.4 and increases when there is increasing NIF loading. The PLA/CS/PEO films are potential materials to apply for long-circulating systems for NIF delivery.

  10. Da-Chaihu-Tang alters the pharmacokinetics of nifedipine in rats and a treatment regimen to avoid this.

    Science.gov (United States)

    He, Ju-Xiu; Ohno, Kenji; Tang, Jun; Hattori, Masao; Tani, Tadato; Akao, Teruaki

    2014-11-01

    To investigate the influence of co-administrated Da-Chaihu-Tang (DCT; a traditional Chinese formulation) on the pharmacokinetics of nifedipine, as well as the safe optimal dosing interval to avoid the adverse interactions. A single dose of DCT was administered with nifedipine simultaneously, 2 h before, 30 min before or 30 min after nifedipine administration. Pharmacokinetics of nifedipine with or without DCT were compared. The influences of DCT on nifedipine intestinal mucosal and hepatic metabolism were studied by using rat in-vitro everted jejunal sac model and hepatic microsomes. A simultaneous co-administration of DCT significantly increased the area under concentration-time curve from time zero to infinity (AUC0-inf ) of nifedipine. In-vitro mechanism investigations revealed that DCT inhibited both the intestinal and the hepatic metabolism of nifedipine. Further study on the optimal dosing interval for nifedipine and DCT revealed that administration of DCT 30 min before or after nifedipine did not significantly change the AUC of nifedipine. The bioavailability of nifedipine is significantly increased by a simultaneous oral co-administration of DCT. This increase is caused by the inhibitory effect of DCT on both the intestinal mucosal and the hepatic metabolism of nifedipine. The dose interval between DCT and nifedipine needs to be set for over 30 min to avoid such drug-drug interactions. © 2014 Royal Pharmaceutical Society.

  11. Study of the stress corrosion cracking susceptibility of type 304 austenitic stainless steel in aqueous solution of MgCl2 at 1250C using the slow - strain - rate technique

    International Nuclear Information System (INIS)

    Heck, N.C.

    1981-01-01

    A study has been made of the stress corrosion cracking susceptibility of type 304 austenitic stainless steel mainly in aqueous solution of MgCl 2 at 125 0 C using the slow strain-rate technique. A system is built up of a tensile test machine and the peripheric equipment. The efficacy of this system has been tested by running experiments for determination of critical potentials in MgCl 2 with or without aditions of NaNO 3 . Critical potentials are found to be between -145 and -160 mV sub(H) for pure MgCl 2 and between -90 and -100 mV sub(H) for MgCl 2 plus 2,5% NaNO 3 . Comparing these results with others of constant load tests, good agreement is found. (Author) [pt

  12. Microstructure development, phase reaction characteristics and mechanical properties of a commercial Al–20%Mg2Si–xCe in situ composite solidified at a slow cooling rate

    International Nuclear Information System (INIS)

    Nordin, Nur Azmah; Farahany, Saeed; Abu Bakar, Tuty Asma; Hamzah, Esah; Ourdjini, Ali

    2015-01-01

    The microstructure, phase reaction characteristics and mechanical properties of fabricated Al–20%Mg 2 Si in situ composite with different contents of cerium have been investigated using optical microscopy, scanning electron microscopy, X-ray diffraction, thermal analysis and hardness tests. The results show that addition of Ce not only refined Mg 2 Si reinforcement particles but also changed the morphology of eutectic Al–Mg 2 Si, Al 5 FeSi (β) intermetallic and Al 5 Cu 2 Mg 8 Si 6 (Q) + Al 2 Cu (Ɵ) phases. It was found that 0.8 wt% Ce is the optimum concentration to transform the phases into refined structures. The structure of the skeleton of Mg 2 Si P changed to a polygonal shape with uniform distribution and decrease in size from 124 μm to 60 μm and increased in density from 12 to 45 particles/mm 2 . Flake-like Mg 2 Si E transformed into a rod-like morphology. In addition, the aspect ratio of needle-like β structures reduced from 40.5 to 22.9, accompanied with an increase of solid fraction for Q + Ɵ phase. Ce addition increased the nucleation temperature of Mg 2 Si P and β phases; however, it had an opposite effect for the Mg 2 Si E and Q + Ɵ phases. The composite hardness increased from 61.32 to 74.15 HV because of refinement of the microstructure. The refining mechanism of Mg 2 Si P and Mg 2 Si E phases is discussed in the current study, and formation of new Ce compounds is believed to be responsible for the refinement effect. - Highlights: • Refinement of Mg 2 Si P , Mg 2 Si E and β-Fe in Al–Mg 2 Si MMC was achieved with 0.8 wt% Ce. • Distribution of Mg 2 Si P particles over the composite samples was reported. • Hardness property was discussed comprehensively related to refinement effect. • Refinement mechanism of primary and eutectic Mg 2 Si with Ce addition was studied.

  13. Study population and treatment titration in the International Nifedipine GITS Study: Intervention as a Goal in Hypertension Treatment (INSIGHT).

    Science.gov (United States)

    Brown, M J; Castaigne, A; de Leeuw, P W; Mancia, G; Rosenthal, T; Ruilope, L M

    1998-12-01

    To ascertain the baseline characteristics of the high-risk hypertensive patients entering the International Nifedipine GITS Study: Intervention as a Goal in Hypertension Treatment (INSIGHT). To determine the success of single and combination therapy in achieving target blood pressures in such a population. INSIGHT is a double-blind, prospective outcome trial comparing the efficacy of the calcium channel blocker, nifedipine GITS, and the thiazide, co-amilozide, in preventing myocardial infarction and stroke. We recruited 2996 men and 3454 women, aged 55-80 years, with blood pressure during placebo run-in >150/95 mmHg or isolated systolic blood pressure >160 mmHg from nine countries. Treatment allocation to nifedipine GITS 30 mg daily or co-amilozide (hydrochlorothiazide 25 mg/amiloride 5 mg) once daily was performed by minimization rather than randomization to balance additional risk factors. This was followed by four optional increases in treatment: dose-doubling of the primary drug, addition of atenolol 25/50 mg or enalapril 5/10 mg, and then any other hypotensive drug excluding calcium blockers or diuretics. Target blood pressure was 140/90 mmHg or a fall > or = 20/10 mmHg. Blood pressure at randomization was 172+/-15 / 99+/-9 mmHg. Thirteen per cent of the patients were previously untreated. The proportions of each additional risk factors were: smoking > 10/day, 29%; cholesterol > 6.43 mmol/l, 52%; family history of premature myocardial infarction or stroke, 21%; diabetes mellitus 20%; left ventricular hypertrophy, 10%; previous myocardial infarction, other presentations of coronary heart disease, and peripheral vascular disease, each 6%; proteinuria, 3%. Fifty-five per cent of patients had one additional risk factor, whereas 33%, 9% and 3% had two, three or more additional risk factors, respectively. The blood pressure (and falls in blood pressure) at the end of titration and at 1 year after minimization was 139+/-12 / 82+/-7 mmHg (33+/-15 / 17+/-9) in the 5226

  14. Plateau hypoxia attenuates the metabolic activity of intestinal flora to enhance the bioavailability of nifedipine.

    Science.gov (United States)

    Zhang, Juanhong; Chen, Yuyan; Sun, Yuemei; Wang, Rong; Zhang, Junmin; Jia, Zhengping

    2018-11-01

    Nifedipine is completely absorbed by the gastrointestinal tract and its pharmacokinetics and metabolism may be influenced by microorganisms. If gut microbes are involved in the metabolism of nifedipine, plateau hypoxia may regulate the bioavailability and the therapeutic effect of nifedipine by altering the metabolic activity of the gut microbiota. We herein demonstrated for the first time that gut flora is involved in the metabolism of nifedipine by in vitro experiments. In addition, based on the results of 16S rRNA analysis of feces in rats after acute plateau, we first confirmed that the plateau environment could cause changes in the number and composition of intestinal microbes. More importantly, these changes in flora could lead to a slower metabolic activity of nifedipine in the body after an acute plateau, resulting in increased bioavailability and therapeutic efficacy of nifedipine. Our research will provide basis and new ideas for changes in the fecal flora of human acutely entering the plateau, and contribute to rational drug use of nifedipine.

  15. The antihypertensive effect of orally administered nifedipine-loaded nanoparticles in spontaneously hypertensive rats.

    Science.gov (United States)

    Kim, Y I; Fluckiger, L; Hoffman, M; Lartaud-Idjouadiene, I; Atkinson, J; Maincent, P

    1997-02-01

    1. The therapeutic use of nifedipine is limited by the rapidity of the onset of its action and its short biological half-life. In order to produce a form devoid of these disadvantages we made nanoparticles of nifedipine from three different polymers, poly-epsilon-caprolactone (PCL), polylactic and glycolic acid (1:1) copolymers (PLAGA), and Eudragit RL/RS (Eudragit). Nifedipine in polyethylene glycol 400 (PEG) solution was used as a control. 2. The average diameters of the nanoparticles ranged from 0.12 to 0.21 micron; the encapsulation ratio was 82% to 88%. 3. In spontaneously hypertensive rats (SHR), the initial rapid fall in systolic arterial blood pressure following oral administration of nifedipine in PEG solution (from 193 +/- 3 to 102 +/- 2 mmHg) was not seen following administration of the same dose in Eudragit nanoparticles (from 189 +/- 2 to 156 +/- 2 mmHg); with PCL and PLAGA nanoparticles the initial fall in blood pressure was significantly reduced (nadirs PCL 124 +/- 2 and PLAGA 113 +/- 2 mmHg). Ten hours following administration, blood pressure in rats administered the nifedipine/PEG preparation had returned to normal (183 +/- 3 mmHg) whereas that of animals given nifedipine in nanoparticles (PCL 170 +/- 3, PLAGA 168 +/- 2, Eudragit 160 +/- 3 mmHg) was still significantly reduced. 4. All of the nanoparticle dosage forms decreased Cmax and increased Tmax and the mean residence time (MRT) values. Relative bioavailability was significantly increased with Eudragit nanoparticles compared to the nifedipine/PEG solution. 5. There was an inverse linear correlation between the fall in blood pressure and plasma nifedipine concentration with all preparations. 6. The nanoparticle nifedipine preparations represent sustained release forms with increased bioavailability, a less pronounced initial antihypertensive effect and a long-lasting action.

  16. Lithium clearance and renal tubular sodium handling during acute and long-term nifedipine treatment in essential hypertension

    DEFF Research Database (Denmark)

    Bruun, N E; Ibsen, H; Skøtt, P

    1988-01-01

    1. In two separate studies the lithium clearance method was used to evaluate the influence of acute and long-term nifedipine treatment on renal tubular sodium reabsorption. 2. In the acute study, after a 4 week placebo period two doses of 20 mg of nifedipine decreased supine blood pressure from 155...... were also unchanged, as were potassium clearance, urine flow and body weight. 3. In the long-term study, lithium clearance, glomerular filtration rate, sodium clearance, potassium clearance, urine flow and body fluid volumes were measured after a 4 weeks placebo period and after 6 and 12 weeks....../101 (20.6/13.5) +/- 11/4 (1.5/0.5) to 139/88 (18.5/11.7) +/- 16/9 (2.1/1.2) mmHg (kPa) (means +/- SD; P less than 0.01). Lithium clearance, glomerular filtration rate and sodium clearance did not change. Therefore the calculated values of absolute proximal and absolute distal sodium reabsorption rates...

  17. Analysis of Fast and Slow Particles Production from the Interaction of 24Mg with Emulsion Nuclei at 4.5 A GeV/c

    International Nuclear Information System (INIS)

    Abdelsalam, A.; Shaat, E.A.; Abou Moussa, Z.; Mater, Z.S.; Badawy, B.M.

    2013-01-01

    The target fragmentation of emulsion nuclei in the interaction of 24 Mg projectile at 4.5 A GeV/c is investigated. The rapidity and angular distributions of the emitted fragments (grey and black) are analyzed in terms of the statistical model. The mean longitudinal velocities and the characteristics spectral velocities of the particle emitting system are determined. The temperatures T of the emitting system for grey and black particles (60 and 6 MeV respectively) are found to be independent of the projectile mass number and target size. The experimental range energy distributions as well as the relationship between the energy and the rate of energy loss for both the grey and black particles can be described well by the outputs of a special computer program called SRIM. The kinetic energy distributions of produced grey and black particles are presented in power law relations and agree well with the predictions of the cascade evaporation model

  18. Comparison of the Efficacy of Nifedipine and Hydralazine in Hypertensive Crisis in Pregnancy

    Directory of Open Access Journals (Sweden)

    Yashar Youefzadeh-Fard

    2011-11-01

    Full Text Available Intravenous hydralazine is a commonly administered arteriolar vasodilator that is effective for hypertensive emergencies associated with pregnancy. Oral nifedipine is an alternative in management of these patients. In this study the efficacy of nifedipine and hydralazine in pregnancy was compared in a group of Iranian patients. Fifty hypertensive pregnant women were enrolled in the study. A randomized clinical trial was performed, in which patients in two groups received intravenus hydralazine or oral nifedipine to achieve target blood pressure reduction. The primary outcomes measured were the time and doses required for desired blood pressure achievement. Secondary measures included urinary output and maternal and neonatal side effects. The time required for reduction in systolic and diastolic blood pressure was shorter for oral nifedipine group (24.0±10.0 min than intravenus Hydralazine group (34.8±18.8 min (P≤0.016. Less frequent doses were required with oral nifedipine (1.2±0.5 compared to intravenus hydralazine (2.1±1.0 (P≤0.0005. There were no episodes of hypotension after hydralazine and one after nifedipine. Nifedipine and hydralazine are safe and effective antihypertensive drugs, showing a controlled and comparable blood pressure reduction in women with hypertensive emergencies in pregnancy. Both drugs reduce episodes of persistent severe hypertension. Considering pharmacokinetic properties of nifedipine such as rapid onset and long duration of action, the good oral bioavailability and less frequent side effects, it looks more preferable in hypertension emergencies of pregnancy than hydralazine.

  19. "Healing Effect of Topical Nifedipine on Skin Wounds of Diabetic Rats "

    Directory of Open Access Journals (Sweden)

    Abbas Ebadi

    2003-07-01

    Full Text Available Non-healing foot ulcers in patients with diabetes are the leading causes of complications such as infection and amputation. Ulceration is the most common single precursor to amputation and has been identified as a causative factor in 85% of lower extremity amputations. It seems that poor outcomes are generally associated with infection, peripheral vascular disease and wounds of increasing depth. Nifedipine, a calcium channel blocker that is mainly used for the treatment of cardiovascular disorders has recently been used to treat wounds caused by peripheral vascular disorders. In present study topical Nifedipine 3% has been used to treat skin wounds in normal and diabetic rats. Effects of Nifedipine were evaluated in three different phases of wound healing process. In both experiments (normal and diabetic rats topical Nifedipine significantly improved inflammatory phase. However, maturation phase was only significantly improved in diabetic rats. Nifedipine did not affect proliferation phase in either group significantly. Overall results of this study showed topical Nifedipine improved skin wound healing process in normal and diabetic rats.

  20. Nifedipine-activated Ca(2+) permeability in newborn rat cortical collecting duct cells in primary culture.

    Science.gov (United States)

    Valencia, L; Bidet, M; Martial, S; Sanchez, E; Melendez, E; Tauc, M; Poujeol, C; Martin, D; Namorado, M D; Reyes, J L; Poujeol, P

    2001-05-01

    To characterize Ca(2+) transport in newborn rat cortical collecting duct (CCD) cells, we used nifedipine, which in adult rat distal tubules inhibits the intracellular Ca(2+) concentration ([Ca(2+)](i)) increase in response to hormonal activation. We found that the dihydropyridine (DHP) nifedipine (20 microM) produced an increase in [Ca(2+)](i) from 87.6 +/- 3.3 nM to 389.9 +/- 29.0 nM in 65% of the cells. Similar effects of other DHP (BAY K 8644, isradipine) were also observed. Conversely, DHPs did not induce any increase in [Ca(2+)](i) in cells obtained from proximal convoluted tubule. In CCD cells, neither verapamil nor diltiazem induced any rise in [Ca(2+)](i). Experiments in the presence of EGTA showed that external Ca(2+) was required for the nifedipine effect, while lanthanum (20 microM), gadolinium (100 microM), and diltiazem (20 microM) inhibited the effect. Experiments done in the presence of valinomycin resulted in the same nifedipine effect, showing that K(+) channels were not involved in the nifedipine-induced [Ca(2+)](i) rise. H(2)O(2) also triggered [Ca(2+)](i) rise. However, nifedipine-induced [Ca(2+)](i) increase was not affected by protamine. In conclusion, the present results indicate that 1) primary cultures of cells from terminal nephron of newborn rats are a useful tool for investigating Ca(2+) transport mechanisms during growth, and 2) newborn rat CCD cells in primary culture exhibit a new apical nifedipine-activated Ca(2+) channel of capacitive type (either transient receptor potential or leak channel).

  1. Slow briefs: slow food....slow architecture

    OpenAIRE

    Crotch, Joanna

    2012-01-01

    We are moving too fast…fast lives, fast cars, fast food…..and fast architecture. We are caught up in a world that allows no time to stop and think; to appreciate and enjoy all the really important things in our lives. Recent responses to this seemingly unstoppable trend are the growing movements of Slow Food and Cittaslow. Both initiatives are, within their own realms, attempting to reverse speed, homogeny, expediency and globalisation, considering the values of regionality, patience, craft, ...

  2. Nifedipine effect on the labelling of blood cells and plasma proteins with Tc-99m

    International Nuclear Information System (INIS)

    Gutfilen, B.; Boasquevisque, E.M.; Bernardo Filho, M.

    1988-01-01

    The labeling of red blood cells (RBC) with Tc-99m depends on the presence of stannous ion (Sn) that helps this radionuclide's fixation on the hemoglobin molecule. Nifedipine is an agent capable to block a specific way where calcius (Ca) ion acrosses the cellular membrane and to bind itself on plasma proteins. The effect of nifedipine in the labeling of RBC and plasma proteins with Tc-99m was studied because of similarities between Ca and Sn ions. Blood with anticoagulant was treated with nifedipine concentration of 10 -6 M for 15 min at 37 0 C. The labeling of RBC with Tc-99m was done incubating with Sn ion solution (3 uM) for different times. The % of radioactivity in RBC was determined. Samples of plasma were precipited with trichloroacetic acid and the % of radiocctivity in insoluble fraction was calculated. The same procedure was done using different nifedipine concentrations and the blood was incubated for 60 min with Sn ion. The determination of the % of Tc-99m labeled in RBC and plasma proteins showed that this drug does not have the capability to alter this incorporation because the results are similar to control. It is suggested that the Sn ions passage across RBC is not altered by nifedipine although this drug could bind to plasma protein, it does not modify the Tc-99m fixation on it. (author) [pt

  3. Comparative efficacy of tamsulosin versus nifedipine for distal ureteral calculi: a meta-analysis.

    Science.gov (United States)

    Wang, Hai; Man, Li Bo; Huang, Guang Lin; Li, Gui Zhong; Wang, Jian Wei

    2016-01-01

    The aim of this study was to systematically compare the therapeutic effect and safety of tamsulosin with nifedipine in medical expulsive therapy for distal ureteral calculi. Databases, including PubMed, EMBASE, the Cochrane Library, and Clinical Trial Register Centers, were comprehensively searched. Relevant randomized controlled trials (RCTs) were selected, and quality assessment was performed according to the Cochrane Handbook. RevMan software was used to analyze the outcome measures, which consisted of expulsion rate, expulsion time, and complications. Twelve RCTs consisting of 4,961 patients were included (tamsulosin group, 2,489 cases; nifedipine group, 2,472 cases). Compared with nifedipine, tamsulosin significantly increased the expulsion rate (risk ratio =1.29, 95% CI [1.25, 1.33], Ptamsulosin was associated with fewer complications than nifedipine (risk ratio =0.45, 95% CI [0.28, 0.72], P=0.0008), and further subgroup analysis showed that tamsulosin was associated with a lower risk of both mild and moderate-to-severe complications. On the bias of current evidence, tamsulosin showed an overall superiority to nifedipine for distal ureteral calculi Tamsulosin was supposed to be the first drug to be recommended to patients willing to receive medical expulsive therapy.

  4. Effect of antihypertensive agents - captopril and nifedipine - on the functional properties of rat heart mitochondria

    Directory of Open Access Journals (Sweden)

    Ivana Kancirová

    2016-06-01

    Full Text Available Objective(s: Investigation of acute effect on cellular bioenergetics provides the opportunity to characterize the possible adverse effects of drugs more comprehensively. This study aimed to investigate the changes in biochemical and biophysical properties of heart mitochondria induced by captopril and nifedipine antihypertensive treatment. Materials and Methods: Male, 12-week-old Wistar rats in two experimental models (in vivo and in vitro were used. In four groups, the effects of escalating doses of captopril, nifedipine and combination of captopril + nifedipine added to the incubation medium (in vitro or administered per os to rat (in vivo on mitochondrial ATP synthase activity and membrane fluidity were monitored. Results: In the in vitro model we observed a significant inhibitory effect of treatment on the ATP synthase activity (P

  5. Comparative efficacy of tamsulosin versus nifedipine for distal ureteral calculi: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Wang H

    2016-03-01

    Full Text Available Hai Wang, Li Bo Man, Guang Lin Huang, Gui Zhong Li, Jian Wei WangDepartment of Urology, Beijing Jishuitan Hospital, Beijing, People’s Republic of China Objective: The aim of this study was to systematically compare the therapeutic effect and safety of tamsulosin with nifedipine in medical expulsive therapy for distal ureteral calculi.Methods: Databases, including PubMed, EMBASE, the Cochrane Library, and Clinical Trial Register Centers, were comprehensively searched. Relevant randomized controlled trials (RCTs were selected, and quality assessment was performed according to the Cochrane Handbook. RevMan software was used to analyze the outcome measures, which consisted of expulsion rate, expulsion time, and complications.Results: Twelve RCTs consisting of 4,961 patients were included (tamsulosin group, 2,489 cases; nifedipine group, 2,472 cases. Compared with nifedipine, tamsulosin significantly increased the expulsion rate (risk ratio =1.29, 95% CI [1.25, 1.33], P<0.0001 and reduced the expulsion time (standard mean difference =-0.39, 95% CI [−0.72, −0.05], P=0.02. Regarding safety, tamsulosin was associated with fewer complications than nifedipine (risk ratio =0.45, 95% CI [0.28, 0.72], P=0.0008, and further subgroup analysis showed that tamsulosin was associated with a lower risk of both mild and moderate-to-severe complications.Conclusion: On the bias of current evidence, tamsulosin showed an overall superiority to nifedipine for distal ureteral calculi <10 mm in aspects of expulsion rate, expulsion time, and safety. Tamsulosin was supposed to be the first drug to be recommended to patients willing to receive medical expulsive therapy.Keywords: tamsulosin, nifedipine, medical expulsive therapy, MET, lower urinary calculi

  6. [Role of food interaction pharmacokinetic studies in drug development. Food interaction studies of theophylline and nifedipine retard and buspirone tablets].

    Science.gov (United States)

    Drabant, S; Klebovich, I; Gachályi, B; Renczes, G; Farsang, C

    1998-09-01

    Due to several mechanism, meals may modify the pharmacokinetics of drug products, thereby eliciting to clinically significant food interaction. Food interactions with the drug substance and with the drug formulation should be distinguished. Food interaction of different drug products containing the same active ingredient can be various depending on the pharmaceutical formulation technology. Particularly, in the case of modified release products, the food/formulation interaction can play an important role in the development of food interaction. Well known example, that bioavailability of theophylline can be influenced in different way (either increased, decreased or unchanged) by concomitant intake of food in the case of different sustained release products. The role and methods of food interaction studies in the different kinds of drug development (new chemical entity, modified release products, generics) are reviewed. Prediction of food effect response on the basis of the physicochemical and pharmacokinetic characteristics of the drug molecule or formulations is discussed. The results of three food interaction studies carried out the products of EGIS Pharmaceuticals Ltd. are also reviewed. The pharmacokinetic parameters of theophyllin 400 mg retard tablet were practically the same in both fasting condition and administration after consumption of a high fat containing standard breakfast. The ingestion of a high fat containing breakfast, increased the AUC of nifedipine from 259.0 +/- 101.2 ng h/ml to 326.7 +/- 122.5 ng h/ml and Cmax from 34.5 +/- 15.9 ng/ml to 74.3 +/- 23.9 ng/ml in case of nifedipine 20 mg retard tablet, in agreement with the data of literature. The statistical evaluation indicated significant differences between the pharmacokinetic parameters in the case of two administrations (before and after meal). The effect of a high fat containing breakfast for a generic version of buspiron 10 mg tablet and the bioequivalence after food consumption were

  7. Nifedipine as a uterine relaxant for external cephalic version: a randomized controlled trial

    NARCIS (Netherlands)

    Kok, Marjolein; Bais, Joke M.; van Lith, Jan M.; Papatsonis, Dimitri M.; Kleiverda, Gunilla; Hanny, Dahrs; Doornbos, Johannes P.; Mol, Ben W.; van der Post, Joris A.

    2008-01-01

    OBJECTIVE: To estimate the effectiveness of nifedipine as a uterine relaxant during external cephalic version to correct breech presentation. METHODS: In this randomized, double-blind, placebo-controlled trial, women with a singleton fetus in breech presentation and a gestational age of 36 weeks or

  8. Analysis of nifedipine content in transdermal drug delivery system using non-destructive visible spectrophotometry technique

    International Nuclear Information System (INIS)

    Normaizira Hamidi; Normaizira Hamidi; Normaizira Hamidi; Mohd Nasir Taib; Mohd Nasir Taib; Wui, Wong Tin; Wui, Wong Tin

    2008-01-01

    The applicability of visible spectrophotometry technique as a tool to determine the drug content of polymeric film for use as a transdermal drug delivery system was investigated. Hydroxypropylmethycellulose (HPMC) was selected as the matrix polymer and nifedipine as the model drug. Blank and nifedipine-loaded HPMC films were prepared using the solvent evaporation method. The absorbance spectra of these films under the visible wavelengths between 400 and 800 nm were assessed and compared against the drug content values obtained by means of the conventional destructive UV- spectrophotometry technique. The latter required the use of a solvent system which contained methanol, a harmful organic component in pharmaceutical applications. The results indicated that the absorbance values, attributed to nifedipine, at the wavelengths of 545, 585, 638 and 755nm were significantly correlated to the drug content values obtained using the chemical assay method (Pearson correlation value: r = 0.990 and p < 0.01). The visible spectrophotometry technique is potentially suitable for use to determine the nifedipine content of films owing to its nature of characterization of transdermal drug delivery system which does not require sample destruction during the process of measurement. The samples are recoverable from test and analysis of the entire batch of samples is possible without the need of solvents and chemical reagents. (author)

  9. Impact of tamsulosin and nifedipine on contractility of pregnant rat ureters in vitro.

    Science.gov (United States)

    Haddad, Lisette; Corriveau, Stéphanie; Rousseau, Eric; Blouin, Simon; Pasquier, Jean-Charles; Ponsot, Yves; Roy-Lacroix, Marie-Ève

    2018-01-01

    To evaluate the in vitro effect of tamsulosin and nifedipine on the contractility of pregnant rat ureters and to perform quantitative analysis of the pharmacological effects. Medical expulsive therapy (MET) is commonly used to treat urolithiasis. However, this treatment is seldom used in pregnant women since no studies support this practice. This was an in vitro study on animal tissue derived from pregnant Sprague-Dawley rats. A total of 124 ureteral segments were mounted in an organ bath system and contractile response to methacholine (MCh) was assessed. Tamsulosin or nifedipine were added at cumulative concentrations (0.001-1 μM). The area under the curve (AUC) from isometric tension measurements was calculated. The effect of pharmacological agents and the respective controls were assessed by calculating the AUC for each 5-min interval. Statistical analyses were performed using the Mann-Whitney-Wilcoxon nonparametric test. Both drugs displayed statistically significant inhibitory activity at concentrations of 0.1 and 1 μM for tamsulosin and 1 μM for nifedipine when calculated as the AUC as compared to DMSO controls. Tamsulosin and nifedipine directly inhibit MCh-induced contractility of pregnant rat ureters. Further work is needed to determine the clinical efficacy of these medications for MET in pregnancy.

  10. Influence of nifedipine on left ventricular perfusion and function in patients with unstable angina: Evaluation with radionuclide techniques

    Energy Technology Data Exchange (ETDEWEB)

    Wall, E.E. van der; Kerkkamp, H.J.; Simoons, M.L.; Rijk, P.P. van; Reiber, J.H.C.; Bom, N.; Lubsen, J.C.; Lie, K.I.

    1986-04-01

    In 1981, a large, double-blind, randomized trial was started in The Netherlands to evaluate the therapeutic effects of nifedipine and/or metoprolol in patients with unstable angina. This study has been called the Holland Interuniversity Nifedipine/metoprolol Trial (HINT) and required several hundred patients to establish potential therapeutic effects. From December 1982 to January 1984 the effects of nifedipine on left ventricular (LV) performance in a subgroup of 52 HINT patients were studied using radionuclide techniques. All patients (23 on nifedipine, 29 controls) underwent thallium-201 scintigraphy or radionuclide angiography just before and 48 h after the start of experimental medication. The radionuclide angiographic studies were also performed at 1 and 4 h after treatment. Nifedipine did not influence the incidence of disapperance of perfusion defects on the 48-h thallium images. No significant differences in overall LV ejections fraction (EF) were seen at any time between nifedipine-treated patients and controls. However, paired observations in 37 patients showed improvement of LVEF after 48 h in 8 patients on nifedipine and in only 1 control patient. Scintigraphic measurements on admission were not related to clinical outcome after 48 h. Concomitant administration of metoprolol did not influence LVEF in either group. It is concluded that nifedipine improves LVEF after 48 h in a subset of patients with unstable angina without affecting myocardial perfusion. This finding indicates that nifedipine has a predominant effect on afterload reduction in patients with unstable angina. Also, early scintigraphic measurements had no significant predictive value for subsequent cardiac events.

  11. Evaluation of zero-order controlled release preparations of nifedipine tablet on dissolution test, together with cost benefit point of view.

    Science.gov (United States)

    Sakurai, Miyuki; Naruto, Ikue; Matsuyama, Kenji

    2008-05-01

    Many generic drugs have been released to decrease medical expenses, but some problems have been reported with regard to bioavailability and safety. In this study, we compared three once-a-day controlled-release preparations of nifedipine by the dissolution test (one branded and two generic preparations). Although the two generic drugs were equivalent to the branded drug according to the criteria listed in the Japanese "Guideline for Bioequivalence Studies of Generic Products", there was still a possibility of problems arising. For example, side effects could be caused by a rapid increase in the blood level of nifedipine with one generic drug, while bioavailability might be inadequate with the other due to its small area under the concentration vs. time curve. When each drug was prescribed at a dosage of 20 mg once daily for two weeks, the difference in the copayment for the patient was only 10 yen. Accordingly, it is important for doctors and pharmacists to carefully consider whether such a slight difference in price is really a benefit for the patient.

  12. A comparative study of atenolol, nifedipine and their combination in ...

    African Journals Online (AJOL)

    1991-01-05

    Jan 5, 1991 ... ambulatory blood pressure measurement, of nHedlplne slow- release (SR), atenolol and the ... common with combination therapy and least common with atenolol. ... sitting position with a mercury sphygmomanometer after 5 minutes of rest. ... Three methods of adverse effects analysis were used. At each.

  13. Slow Antihydrogen

    International Nuclear Information System (INIS)

    Gabrielse, G.; Speck, A.; Storry, C.H.; Le Sage, D.; Guise, N.; Larochelle, P.C.; Grzonka, D.; Oelert, W.; Schepers, G.; Sefzick, T.; Pittner, H.; Herrmann, M.; Walz, J.; Haensch, T.W.; Comeau, D.; Hessels, E.A.

    2004-01-01

    Slow antihydrogen is now produced by two different production methods. In Method I, large numbers of H atoms are produced during positron-cooling of antiprotons within a nested Penning trap. In a just-demonstrated Method II, lasers control the production of antihydrogen atoms via charge exchange collisions. Field ionization detection makes it possible to probe the internal structure of the antihydrogen atoms being produced - most recently revealing atoms that are too tightly bound to be well described by the guiding center atom approximation. The speed of antihydrogen atoms has recently been measured for the first time. After the requested overview, the recent developments are surveyed

  14. A comparison of nifedipine and tamsulosin as medical expulsive therapy for the management of lower ureteral stones without ESWL

    Science.gov (United States)

    Cao, Dehong; Yang, Lu; Liu, Liangren; Yuan, Haichao; Qian, Shenqiang; Lv, Xiao; Han, Pin; Wei, Qiang

    2014-01-01

    Administration of nifedipine or tamsulosin has been suggested to augment stone expulsion rates. We aimed to compare the stone expulsion rates and adverse effects associated with the use of nifedipine or tamsulosin as medical expulsive therapy (MET) for the management of lower ureteral stones (LUS) without extracorporeal shock wave lithotripsy (ESWL) via a literature review and meta-analysis. Relevant randomized controlled trials (RCTs) were identified from the Medline, EMBASE, Cochrane CENTRAL, and Google Scholar databases. Finally, a total of 7 RCTs with 3897 patients were included. Our meta-analysis showed that tamsulosin could significantly increase the stone expulsion rate relative to nifedipine in patients with LUS (random-effects model; risk ratio [RR] = 0.81; 95% confidence interval [CI] = 0.75–0.88; P tamsulosin was more effective than nifedipine in patients with LUS, as evidenced by the higher stone expulsion rate. Tamsulosin treatment should therefore be considered for patients with LUS. PMID:24919112

  15. Mechanisms of Nifedipine-Downregulated CD40L/sCD40L Signaling in Collagen Stimulated Human Platelets.

    Directory of Open Access Journals (Sweden)

    Tso-Hsiao Chen

    Full Text Available The platelet-derived soluble CD40L (sCD40L release plays a critical role in the development of atherosclerosis. Nifedipine, a dihydropyridine-based L-type calcium channel blocker (CCB, has been reported to have an anti-atherosclerotic effect beyond its blood pressure-lowering effect, but the molecular mechanisms remain unclear. The present study was designed to investigate whether nifedipine affects sCD40L release from collagen-stimulated human platelets and to determine the potential role of peroxisome proliferator-activated receptor-β/-γ (PPAR-β/-γ. We found that treatment with nifedipine significantly inhibited the platelet surface CD40L expression and sCD40L release in response to collagen, while the inhibition was markedly reversed by blocking PPAR-β/-γ activity with specific antagonist such as GSK0660 and GW9662. Meanwhile, nifedipine also enhanced nitric oxide (NO and cyclic GMP formation in a PPAR-β/-γ-dependent manner. When the NO/cyclic GMP pathway was suppressed, nifedipine-mediated inhibition of sCD40L release was abolished significantly. Collagen-induced phosphorylation of p38MAPK, ERK1/2 and HSP27, matrix metalloproteinase-2 (MMP-2 expression/activity and reactive oxygen species (ROS formation were significantly inhibited by nifedipine, whereas these alterations were all attenuated by co-treatment with PPAR-β/-γ antagonists. Collectively, these results demonstrate that PPAR-β/-γ-dependent pathways contribute to nifedipine-mediated downregulation of CD40L/sCD40L signaling in activated platelets through regulation of NO/ p38MAPK/ERK1/2/HSP27/MMP-2 signalings and provide a novel mechanism regarding the anti-atherosclerotic effect of nifedipine.

  16. FORMULATION AND IN VITRO EVALUATION OF NIFEDIPINE FLOATING MATRIX TABLETS BY USING NATURAL POLYMERS

    OpenAIRE

    Shaik Asha Begum*, Ramya Sri Sura , Bandlamudi.Vineela, Tirumalasetti. V. Siva Naga Sai Bhanu Sree, Moghal. Rafiya Begum, Abdul. Kareemunnisa

    2018-01-01

    In the present research work gastro retentive floating matrix formulation of Nifedipine by using Natural polymers were developed. Initially analytical method development was done for the drug molecule. Absorption maxima was determined based on that calibration curve was developed by using different concentrations. Gas generating agent sodium bicarbonate concentration was optimised. Then the formulation was developed by using different concentrations of polymers Xanthan gum, guar gum and Karay...

  17. Hemodynamic effects of metoprolol and nifedipine in angina pectoris measured by isotope technique

    Energy Technology Data Exchange (ETDEWEB)

    Bostroem, P.A.

    1988-01-01

    In order to evaluate the therapeutic effects of metoprolol, nifedipine, and their combination, 11 patients with secondary angina pectoris and with thallium tomographic findings indicating coronary artery disease were studied before and after these three treatment regimes in a single-blind cross-over study. The therapeutic effect was measured by standardized working test and isotope angiocardiography, which enabled evaluation of left ventricular ejection fraction, stroke volume, and phase analysis of left ventricular contraction. Treatment with metoprolol and combination therapy increased work performance. Ejection fraction did not differentiate the treatment regimes, whereas stroke volume was significantly lower at work and heart rate higher at rest and at work during nifedipine treatment compared to either metoprolol or combination treatment (p less than 0.05). Cardiac output was significantly reduced during nifedipine and metoprolol treatment during work (p less than 0.05). Phase improved after all therapeutic regimes, but reached significance only during the metoprolol treatment period at rest (p less than 0.05).

  18. Transient myocardial ischemia during nifedipine therapy in stable angina pectoris, and its relation to coronary collateral flow and comparison with metoprolol

    DEFF Research Database (Denmark)

    Egstrup, K; Andersen, P E

    1993-01-01

    There are conflicting results concerning the anti-ischemic effect of nifedipine in patients with chronic stable angina. Therefore, the purpose of this study was to assess whether the anti-ischemic effect of nifedipine may be related to coronary collateral circulation. Forty-one patients with stable...... of collateral circulation. In 17 patients, angiographically poor or no collateral flow was observed (group 1), and 24 had good collateral flow (group 2). Nifedipine was administered to 20 patients (8 in group 1, and 12 in group 2). In group 1, nifedipine reduced the frequency of total and asymptomatic ischemic...

  19. Endoplasmic reticulum stress mediating downregulated StAR and 3-beta-HSD and low plasma testosterone caused by hypoxia is attenuated by CPU86017-RS and nifedipine

    Directory of Open Access Journals (Sweden)

    Liu Gui-Lai

    2012-01-01

    Full Text Available Abstract Background Hypoxia exposure initiates low serum testosterone levels that could be attributed to downregulated androgen biosynthesizing genes such as StAR (steroidogenic acute regulatory protein and 3-beta-HSD (3-beta-hydroxysteroid dehydrogenase in the testis. It was hypothesized that these abnormalities in the testis by hypoxia are associated with oxidative stress and an increase in chaperones of endoplasmic reticulum stress (ER stress and ER stress could be modulated by a reduction in calcium influx. Therefore, we verify that if an application of CPU86017-RS (simplified as RS, a derivative to berberine could alleviate the ER stress and depressed gene expressions of StAR and 3-beta-HSD, and low plasma testosterone in hypoxic rats, these were compared with those of nifedipine. Methods Adult male Sprague-Dawley rats were randomly divided into control, hypoxia for 28 days, and hypoxia treated (mg/kg, p.o. during the last 14 days with nifedipine (Nif, 10 and three doses of RS (20, 40, 80, and normal rats treated with RS isomer (80. Serum testosterone (T and luteinizing hormone (LH were measured. The testicular expressions of biomarkers including StAR, 3-beta-HSD, immunoglobulin heavy chain binding protein (Bip, double-strand RNA-activated protein kinase-like ER kinase (PERK and pro-apoptotic transcription factor C/EBP homologous protein (CHOP were measured. Results In hypoxic rats, serum testosterone levels decreased and mRNA and protein expressions of the testosterone biosynthesis related genes, StAR and 3-beta-HSD were downregulated. These changes were linked to an increase in oxidants and upregulated ER stress chaperones: Bip, PERK, CHOP and distorted histological structure of the seminiferous tubules in the testis. These abnormalities were attenuated significantly by CPU86017-RS and nifedipine. Conclusion Downregulated StAR and 3-beta-HSD significantly contribute to low testosterone in hypoxic rats and is associated with ER stress

  20. Microstructure development, phase reaction characteristics and mechanical properties of a commercial Al–20%Mg{sub 2}Si–xCe in situ composite solidified at a slow cooling rate

    Energy Technology Data Exchange (ETDEWEB)

    Nordin, Nur Azmah [Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia (UTM), 81310, Johor Bahru (Malaysia); Farahany, Saeed [Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia (UTM), 81310, Johor Bahru (Malaysia); Faculty of Materials and Mechanical Engineering, Buein Zahra Technical University, 3451745346 (Iran, Islamic Republic of); Abu Bakar, Tuty Asma, E-mail: tuty@mail.fkm.utm.my [Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia (UTM), 81310, Johor Bahru (Malaysia); Hamzah, Esah [Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia (UTM), 81310, Johor Bahru (Malaysia); Ourdjini, Ali [Department of Mechanical Engineering, Faculty of Engineering, University of Ottawa (Canada)

    2015-11-25

    The microstructure, phase reaction characteristics and mechanical properties of fabricated Al–20%Mg{sub 2}Si in situ composite with different contents of cerium have been investigated using optical microscopy, scanning electron microscopy, X-ray diffraction, thermal analysis and hardness tests. The results show that addition of Ce not only refined Mg{sub 2}Si reinforcement particles but also changed the morphology of eutectic Al–Mg{sub 2}Si, Al{sub 5}FeSi (β) intermetallic and Al{sub 5}Cu{sub 2}Mg{sub 8}Si{sub 6} (Q) + Al{sub 2}Cu (Ɵ) phases. It was found that 0.8 wt% Ce is the optimum concentration to transform the phases into refined structures. The structure of the skeleton of Mg{sub 2}Si{sub P} changed to a polygonal shape with uniform distribution and decrease in size from 124 μm to 60 μm and increased in density from 12 to 45 particles/mm{sup 2}. Flake-like Mg{sub 2}Si{sub E} transformed into a rod-like morphology. In addition, the aspect ratio of needle-like β structures reduced from 40.5 to 22.9, accompanied with an increase of solid fraction for Q + Ɵ phase. Ce addition increased the nucleation temperature of Mg{sub 2}Si{sub P} and β phases; however, it had an opposite effect for the Mg{sub 2}Si{sub E} and Q + Ɵ phases. The composite hardness increased from 61.32 to 74.15 HV because of refinement of the microstructure. The refining mechanism of Mg{sub 2}Si{sub P} and Mg{sub 2}Si{sub E} phases is discussed in the current study, and formation of new Ce compounds is believed to be responsible for the refinement effect. - Highlights: • Refinement of Mg{sub 2}Si{sub P}, Mg{sub 2}Si{sub E} and β-Fe in Al–Mg{sub 2}Si MMC was achieved with 0.8 wt% Ce. • Distribution of Mg{sub 2}Si{sub P} particles over the composite samples was reported. • Hardness property was discussed comprehensively related to refinement effect. • Refinement mechanism of primary and eutectic Mg{sub 2}Si with Ce addition was studied.

  1. Microemulsion Transdermal Formulation for Simultaneous Delivery of Valsartan and Nifedipine: Formulation by Design.

    Science.gov (United States)

    Sood, Jatin; Sapra, Bharti; Tiwary, Ashok K

    2017-08-01

    The objective of the study was to optimize the proportion of different components for formulating oil in water microemulsion formulation meant for simultaneous transdermal delivery of two poorly soluble antihypertensive drugs. Surface response methodology of Box-Behnken design was utilized to evaluate the effect of two oils (Captex 500 - x1 and Capmul MCM - x2) and surfactant (Acrysol EL135 - x3) on response y1 (particle size), y2 (solubility of valsartan), and y3 (solubility of nifedipine). The important factors which significantly affected the responses were identified and validated using ANOVA. The model was diagnosed using normal plot of residuals and Box-Cox plot. The design revealed an inverse correlation between particle size and concentration of Capmul MCM and Acrysol EL 135. However, an increase in concentration of Captex 500 led to an increase in particle size of microemulsion. Solubility of valsartan decreased while that of nifedipine increased with increase in concentration of Captex 500. Capmul MCM played a significant role in increasing the solubility of valsartan. The effect of Acrysol EL 135 on solubility of both drugs, although significant, was only marginal as compared to that of Captex 500 and Capmul MCM. The optimized microemulsion was able to provide an enhancement ratio of 27.21 and 63.57-fold for valsartan and nifedipine, respectively, with respect to drug dispersion in aqueous surfactant system when evaluated for permeation studies. The current studies candidly suggest the scope of microemulsion systems for solubilizing as well as promoting the transport of both drugs across rat skin at an enhanced permeation rate.

  2. Oesophageal food impaction in achalasia treated with Coca-Cola and nifedipine.

    Science.gov (United States)

    Koumi, Andriani; Panos, Marios Zenon

    2010-01-01

    Achalasia is characterised by the loss of peristaltic movement in the distal oesophagus and failure of the lower oesophageal sphincter relaxation, which results in impaired oesophageal emptying. We report a case of a 92-year-old frail woman with a history of achalasia, who presented with acute oesophageal obstruction due to impaction of a large amount of food material. She was treated successfully with nifedipine, in combination with Coca-Cola (original product, not sugar free), so avoiding the risks associated with repeated endoscopic intubation and piecemeal removal of the oesophageal content.

  3. Solubility enhancement, physicochemical characterization and formulation of fast-dissolving tablet of nifedipine-betacyclodextrin complexes

    Directory of Open Access Journals (Sweden)

    Swati Changdeo Jagdale

    2012-03-01

    Full Text Available The main objective of the study was to enhance the dissolution of nifedipine, a poorly water soluble drug by betacyclodextrin complexation and to study the effect of the preparation method on the in vitro dissolution profile. The stoichiometric ratio determined by phase solubility analysis for inclusion complexation of nifedipine with β-cyclodextrin was 1:1. Binary complex was prepared by different methods and was further characterized using XRD, DSC and FT-IR. A saturation solubility study was carried out to evaluate the increase in solubility of nifedipine. The optimized complex was formulated into fast-dissolving tablets by using the superdisintegrants Doshion P544, pregelatinized starch, crospovidone, sodium starch glycolate and croscarmellose sodium by direct compression. Tablets were evaluated for friability, hardness, weight variation, disintegration and in vitro dissolution. Tablets showed an enhanced dissolution rate compared to pure nifedipine.Este estudo teve por objetivo principal incrementar a dissolução do nifedipino, fármaco pouco solúvel em água, por meio de sua complexação com β-ciclodextrina e estudar o efeito do método de preparação sobre o perfil de dissolução in vitro. A razão estequiométrica, determinada por ensaio de solubilidade de fase, para a complexação de nifedipino por inclusão em β-ciclodextrina foi 1:1. O complexo binário foi preparado por diferentes métodos, sendo caracterizado utilizando-se difratometria de raios X (XRD, calorimetria diferencial de varredura (DSC e espectroscopia no infravermelho com transformada de Fourier (FT-IR. Realizou-se estudo de solubilidade de saturação para avaliar o incremento da solubilidade do nifedipino. O complexo otimizado foi formulado em comprimidos de dissolução rápida preparados por compressão direta, nos quais se utilizaram os superdesintegrantes Doshion P544, amido pré-gelatinizado, crospovidona, amidoglicolato de sódio e croscarmelose s

  4. FROM SLOW FOOD TO SLOW TOURISM

    Directory of Open Access Journals (Sweden)

    Bac Dorin Paul

    2014-12-01

    Full Text Available One of the effects of globalization is the faster pace of our lives. This rhythm can be noticed in all aspects of life: travel, work, shopping, etc. and it has serious negative effects. It has become common knowledge that stress and speed generate serious medical issues. Food and eating habits in the modern world have taken their toll on our health. However, some people took a stand and argued for a new kind of lifestyle. It all started in the field of gastronomy, where a new movement emerged – Slow Food, based on the ideas and philosophy of Carlo Petrini. Slow Food represents an important adversary to the concept of fast food, and is promoting local products, enjoyable meals and healthy food. The philosophy of the Slow Food movement developed in several directions: Cittaslow, slow travel and tourism, slow religion and slow money etc. The present paper will account the evolution of the concept and its development during the most recent years. We will present how the philosophy of slow food was applied in all the other fields it reached and some critical points of view. Also we will focus on the presence of the slow movement in Romania, although it is in a very early stage of development. The main objectives of the present paper are: to present the chronological and ideological evolution of the slow movement; to establish a clear separation of slow travel and slow tourism, as many mistake on for the other; to review the presence of the slow movement in Romania. Regarding the research methodology, information was gathered from relevant academic papers and books and also from interviews and discussions with local entrepreneurs. The research is mostly theoretical and empirical, as slow food and slow tourism are emerging research themes in academic circles.

  5. Movement - uncontrolled or slow

    Science.gov (United States)

    Dystonia; Involuntary slow and twisting movements; Choreoathetosis; Leg and arm movements - uncontrollable; Arm and leg movements - uncontrollable; Slow involuntary movements of large muscle groups; Athetoid movements

  6. Chronobiological analysis by ambulatory blood pressure monitoring of the hyperbaric and hypobaric indexes for evaluation of the antihypertensive effect of long-acting nifedipine.

    Science.gov (United States)

    Seki, Shingo; Taniguchi, Masayuki; Ohsawa, Shingo; Koga, Atsushi; Ito, Takashi; Kunoh, Mamoru; Imamoto, Satoshi; Miyazaki, Hidekazu; Takeda, Satoshi; Iwano, Keiji; Satoh, Chikashi; Kanae, Kiyoshi; Mochizuki, Seibu

    2005-10-01

    It has been suggested that chronobiology can provide new insights into the evaluation and treatment of cardiovascular disease. In the present study the hyperbaric index (hyperBI) and hypobaric index (hypoBI) were compared with the mean blood pressure (BP) over 24 h to evaluate the antihypertensive effect of long-acting nifedipine on essential hypertension. Fourteen patients were treated with nifedipine CR (20-40 mg/day) for 6 months. Ambulatory BP monitoring was performed before and after treatment. The hyperBI (mmHg . h/day) was calculated as the integrated BP area above the conventional upper limit (140/90 mmHg for the daytime and 120/80 mmHg at night), and the hypoBI was calculated as the integrated BP area below the conventional lower limit (110/60 mmHg for the daytime and 100/50 mmHg at night). At baseline, both the systolic and diastolic 24-h hyperBI values closely correlated with the 24-h mean BP (r=0.994 and 0.935, p<0.0001). Treatment with nifedipine significantly lowered both the 24-h mean systolic and diastolic BP (143+/-14/89 +/-12 to 124+/-16/80+/-8 mmHg, p<0.001/p=0.001), as well as the casual BP (167+/-11/101 +/-8 to 140+/-13/86+/-10 mmHg, p<0.001/p<0.01). Reduction of both the systolic and diastolic hyperBI values was statistically significant over the 24-h period (274+/-266 to 90+/-155, p=0.009; 145+/-187 to 41+/-63, p=0.024), as well as during the daytime (200+/-181 to 66+/-116, p=0.014; 105+/-120 to 24+/-38, p=0.017) and at night (systolic, 74+/-106 to 24+/-52, p=0.021). The 24-h mean BP was normalized, but a small excess BP load persisted despite treatment. There was no significant increase of systolic hypoBI during the 24-h period (1+/-2 to 25+/-30, p=0.065), the daytime (0+/-0 to 14+/-38, p=0.20), or at night (1+/-3 to 11+/-19, p=0,052). Similar findings were obtained for diastolic hypoBI. Nifedipine CR improved the 24-h hyperBI and mean BP without causing excessive hypotension. These 2 parameters have a close relationship when assessment is

  7. Does a kampo medicine containing schisandra fruit affect pharmacokinetics of nifedipine like grapefruit juice?

    Science.gov (United States)

    Makino, Toshiaki; Mizuno, Fumika; Mizukami, Hajime

    2006-10-01

    Herb-drug interaction has attracted attention as medicinal topics recently. However, the drug information is sometimes confusing. Previous in vitro studies revealed that schisandra fruit had strong inhibitory effect on CYP3A4 and claimed the possibilities of its herb-drug interaction. In the present study, we evaluated the inhibitory effects of schisandra fruit and shoseiryuto, an herbal formula in Japanese traditional kampo medicine containing eight herbal medicines including schisandra fruit, on rat CYP3A activity in vitro, and the effect of shoseiryuto on pharmacokinetics of nifedipine in rats, in comparison with those of grapefruit juice, a well-characterized natural CYP3A inhibitor. Shoseiryuto and its herbal constituents, schisandra fruit, ephedra herb and cinnamon bark exhibited in vitro inhibitory effect of CYP3A. Although shoseiryuto inhibited rat CYP3A activity in vitro with a degree comparable to grapefruit juice, shoseiryuto did not significantly affect a plasma concentration profile of nifedipine in rats as grapefruit juice did. These results indicate that in vivo experiments using the extract of herbal medicine prepared with the same dosage form as patients take are necessary to provide proper information about herb-drug interaction.

  8. Long-term follow up of children exposed in utero to nifedipine or ritodrine for the management of preterm labour

    NARCIS (Netherlands)

    Houtzager, B. A.; Hogendoorn, S. M.; Papatsonis, D. N. M.; Samsom, J. F.; van Geijn, H. P.; Bleker, O. P.; van Wassenaer, A. G.

    2006-01-01

    OBJECTIVE: To compare the long-term psychosocial and motor effects on children exposed in utero to nifedipine or ritodrine for the management of preterm labour. DESIGN: Randomised controlled trial. SETTING: Multicentre study in two university and one primary hospital in the Netherlands. POPULATION:

  9. Nifedipine for the poor-risk elderly patient with achalasia: objective response demonstrated by solid meal study

    International Nuclear Information System (INIS)

    Thomas, E.; Lebow, R.A.; Gubler, R.J.; Bryant, L.R.

    1984-01-01

    We described an 84-year-old woman with symptomatic achalasia who refused both dilation and surgical treatment. She was treated with the calcium channel blocking drug nifedipine, with significant relief of symptoms. Objective evidence of response to the drug was confirmed by using an egg salad sandwich meal labeled with 99mTc-DTPA

  10. Determination of nifedipine in dog plasma by high-performance liquid chromatography with tandem mass spectrometric detection.

    Science.gov (United States)

    Pan, Xigui; Zhou, Shunchang; Fu, Qinqin; Hu, Xianming; Wu, Jianhong

    2014-07-01

    Nifedipine is a dihydropyridine calcium channel blocker used widely in the management of hypertension and other cardiovascular disorders. In this work, a simple, rapid and sensitive liquid chromatography/tandem mass spectrometry method was developed and validated to determine nifedipine in dog plasma using nimodipine as the internal standard. Chromatographic separation was carried out on a C₈ column. The mobile phase consisted of a mixture of acetonitrile, water and formic acid (60:40:0.2, v/v/v) at a flow rate of 0.5 mL/min. Detection was performed on a triple quadrupole tandem mass spectrometer in selected reaction monitoring mode via an atmospheric pressure chemical ionization source. The method has a lower limit of quantification of 0.20 ng/mL with consumption of plasma as low as 0.05 mL. The linear calibration curves were obtained in the concentration range of 0.20-50.0 ng/mL (r = 0.9948). The recoveries of the liquid extraction method were 74.5-84.1%. Intra-day and inter-day precisions were 4.1-8.8 and 6.7-7.4%, respectively. The quantification was not interfered with by other plasma components and the method was applied to determine nifedipine in plasma after a single oral administration of two controlled-release nifedipine tablets to beagle dogs. Copyright © 2013 John Wiley & Sons, Ltd.

  11. Transient myocardial ischemia during daily life in rest and exertional angina pectoris and comparison of effectiveness of metoprolol versus nifedipine

    DEFF Research Database (Denmark)

    Ardissino, D; Savonitto, S; Egstrup, K

    1991-01-01

    life (p less than 0.05) irrespective of the patients' clinical characteristics. Nifedipine was ineffective, particularly in patients with angina predominantly on effort and with a moderate to severe reduction in exercise tolerance. It is concluded that in patients with mixed angina, ischemic episodes...

  12. Nifedipine for the poor-risk elderly patient with achalasia: objective response demonstrated by solid meal study

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, E.; Lebow, R.A.; Gubler, R.J.; Bryant, L.R.

    1984-03-01

    We described an 84-year-old woman with symptomatic achalasia who refused both dilation and surgical treatment. She was treated with the calcium channel blocking drug nifedipine, with significant relief of symptoms. Objective evidence of response to the drug was confirmed by using an egg salad sandwich meal labeled with 99mTc-DTPA.

  13. A comparison of nifedipine and tamsulosin as medical expulsive therapy for the management of lower ureteral stones without ESWL.

    Science.gov (United States)

    Cao, Dehong; Yang, Lu; Liu, Liangren; Yuan, Haichao; Qian, Shenqiang; Lv, Xiao; Han, Pin; Wei, Qiang

    2014-06-11

    Administration of nifedipine or tamsulosin has been suggested to augment stone expulsion rates. We aimed to compare the stone expulsion rates and adverse effects associated with the use of nifedipine or tamsulosin as medical expulsive therapy (MET) for the management of lower ureteral stones (LUS) without extracorporeal shock wave lithotripsy (ESWL) via a literature review and meta-analysis. Relevant randomized controlled trials (RCTs) were identified from the Medline, EMBASE, Cochrane CENTRAL, and Google Scholar databases. Finally, a total of 7 RCTs with 3897 patients were included. Our meta-analysis showed that tamsulosin could significantly increase the stone expulsion rate relative to nifedipine in patients with LUS (random-effects model; risk ratio [RR] = 0.81; 95% confidence interval [CI] = 0.75-0.88; P < 0.00001). The subgroup analysis indicated no statistically significant difference between the drugs with regard to minor or major adverse effects (fixed-effect model; RR = 1.19, 95% CI = 0.91-1.54, P = 0.20; and RR = 1.63, 95% CI = 0.22-11.82, P = 0.63, respectively). This meta-analysis demonstrated that tamsulosin was more effective than nifedipine in patients with LUS, as evidenced by the higher stone expulsion rate. Tamsulosin treatment should therefore be considered for patients with LUS.

  14. Determination and correlation thermodynamic models for solid–liquid equilibrium of the Nifedipine in pure and mixture organic solvents

    International Nuclear Information System (INIS)

    Wu, Gang; Hu, Yonghong; Gu, Pengfei; Yang, Wenge; Wang, Chunxiao; Ding, Zhiwen; Deng, Renlun; Li, Tao; Hong, Housheng

    2016-01-01

    Highlights: • The solubility increased with increasing temperature. • The data were fitted using the modified Apelblat equation in pure solvents. • The data were fitted using the CNIBS/R-K model in binary solvent mixture. - Abstract: Knowledge of thermodynamic parameters on corresponding solid-liquid equilibrium of nifedipine in different solvents is essential for a preliminary study of pharmaceutical engineering and industrial applications. In this paper, a gravimetric method was used to correct the solid-liquid equilibrium of nifedipine in methanol, ethanol, 1-butanol, acetone, acetonitrile, ethyl acetate and tetrahydrofuran pure solvents as well as in the (tetrahydrofuran + acetonitrile) mixture solvents at temperatures from 278.15 K to 328.15 K under 0.1 MPa. For the temperature range investigation, the solubility of nifedipine in the solvents increased with increasing temperature. The solubility of nifedipine in tetrahydrofuran is superior to other selected pure solvents. The modified Apelblat model, the Buchowski-Ksiazaczak λh model, and the ideal model were adopted to describe and predict the change tendency of solubility. Computational results showed that the modified Apelblat model stood out to be more suitable with the higher accuracy. The solubility values were fitted using a modified Apelblat model, a variant of the combined nearly ideal binary solvent/Redich-Kister (CNIBS/R-K) model and Jouyban-Acree model in (tetrahydrofuran + acetonitrile) binary solvent mixture. Computational results showed that the CNIBS/R-K model had more advantages than other models.

  15. PROTECTIVE EFFECT OF POLYMYXINE B AND NIFEDIPINE ON DIABETIC COMPLICATIONS IN RAT: ROLE OF PROTEIN KINASE C

    Directory of Open Access Journals (Sweden)

    H. Mehrani

    2003-08-01

    Full Text Available Patients with diabetes mellitus (DM, experience significant morbidity and mortality from microvascular retinopathy, nephropathy and neuropathy. Hyperglycemia can induce diabetic complications through multiple pathways. Activation of protein kinase C (PKC by hyperglycemia is one of the pathways which causes diabetic complications. Effect of nifedipine (a calcium channel blocker, and polymyxine B sulphate (a Protein kinase C inhibitor was studied in adult male Sprague- dawley rats, who was made diabetic with streptozotocin. PKC activity was determined in tissues and serum enzymes and metabolite level was measured in all controls, diabetic and drug treated animals. The results showed that, levels of the, urea (two –fold, creatinine (60%, triglyceride (two-fold and liver alanine transaminase (ALT activity (two-fold, were significantly increased in diabetic group. In nifedipine, treated diabetic group, although urea and creatinine level was increased, but liver enzymes were not significantly different from those of control group. In diabetic group which was treated with polymyxine, all the measured metabolites and enzyme levels were the same as the control group, except glucose level which was increased and liver glycogen was decreased significantly. Protein kinase C activity in the cytoplasm of diabetic liver was increased comparing to its control group (5.73 ± 0.56 Vs, 4.00 ± 0.62. The enzyme activity in the plasma membranes of untreated and nifedipine treated diabetic groups was significantly increased (6.2 ± 0.42 and 3.66 ± 0.31 Vs 2.38 ± 0.36. These results show that polymyxine is more effective than nifedipine against protein kinase C activity in diabetic complications. In conclusion our results show that, liver and kidney damage in DM are related to PKC activation. The fact that polymyxine prevents diabetic related increase in PKC activity more than nifedipine, support the hypothesis that different PKC isozymes may play different roles

  16. Mechanistic study of solubility enhancement of nifedipine using vitamin E TPGS or solutol HS-15.

    Science.gov (United States)

    Rajebahadur, Minal; Zia, Hossein; Nues, Anthony; Lee, Chong

    2006-01-01

    The objective of our study was to find mechanisms responsible for solubility enhancement of nifedipine in solid dispersions of vitamin E TPGS and/or solutol HS-15. Solid dispersions of nifedipine with selected polymers such as vitamin E TPGS, solutol HS-15, PEG(1,000), and lipocol C-10 of varying drug/polymer ratios were prepared by a fusion method. The solubility enhancement was found to be in the order of vitamin E TPGS > solutol HS-15 > lipocol C-10 > PEG(1,000). Lipocol C-10, with a similar hydrophilic-lipophilic value as vitamin E TPGS, showed a comparable retained solubility enhancement during saturation solubility studies but had lower dissolution profile. Overall, vitamin E TPGS showed the best solubility and dissolution performance, while solutol HS-15 and lipocol C-10 demonstrated moderate solubility enhancements. Solid dispersions of vitamin E TPGS as prepared by microfluidization technique initially showed slightly higher solubility compared with samples prepared by fusion method, but eventually it became the same as the study progressed. However, solid dispersion of solutol HS-15 as prepared by microfluidization demonstrated a significant, sustained increased in solubility over its sample when prepared by fusion method. Based on these results, we concluded that enhanced solubility using vitamin E TPGS and solutol HS-15 resulted from a partial conversion of crystalline drug to the amorphous form, increase in wettability of the drug by water soluble polymers, better separation of drug particles, micellar solubilization of drug by high concentrations of surfactant polymers, and interaction between polymer and drug at the molecular level.

  17. Nifedipine inhibits advanced glycation end products (AGEs) and their receptor (RAGE) interaction-mediated proximal tubular cell injury via peroxisome proliferator-activated receptor-gamma activation

    International Nuclear Information System (INIS)

    Matsui, Takanori; Yamagishi, Sho-ichi; Takeuchi, Masayoshi; Ueda, Seiji; Fukami, Kei; Okuda, Seiya

    2010-01-01

    Research highlights: → Nifedipine inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by GW9662, an inhibitor of peroxisome proliferator-activated receptor-γ. → GW9662 treatment alone increased RAGE mRNA levels in tubular cells. → Nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-κB activation and increases in intercellular adhesion molecule-1 and transforming growth factor-β gene expression in tubular cells, all of which were blocked by GW9662. -- Abstract: There is a growing body of evidence that advanced glycation end products (AGEs) and their receptor (RAGE) interaction evokes oxidative stress generation and subsequently elicits inflammatory and fibrogenic reactions, thereby contributing to the development and progression of diabetic nephropathy. We have previously found that nifedipine, a calcium-channel blocker (CCB), inhibits the AGE-induced mesangial cell damage in vitro. However, effects of nifedipine on proximal tubular cell injury remain unknown. We examined here whether and how nifedipine blocked the AGE-induced tubular cell damage. Nifedipine, but not amlodipine, a control CCB, inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-γ (PPARγ). GW9662 treatment alone was found to increase RAGE mRNA levels in tubular cells. Further, nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-κB activation and increases in intercellular adhesion molecule-1 and transforming growth factor-beta gene expression in tubular cells, all of which were blocked by GW9662. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-oxidative and anti-inflammatory agent against AGEs in tubular cells by suppressing RAGE expression via PPARγ activation.

  18. Nifedipine inhibits advanced glycation end products (AGEs) and their receptor (RAGE) interaction-mediated proximal tubular cell injury via peroxisome proliferator-activated receptor-gamma activation

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Takanori [Department of Pathophysiology and Therapeutics of Diabetic Vascular Complications, Kurume University School of Medicine, Kurume (Japan); Yamagishi, Sho-ichi, E-mail: shoichi@med.kurume-u.ac.jp [Department of Pathophysiology and Therapeutics of Diabetic Vascular Complications, Kurume University School of Medicine, Kurume (Japan); Takeuchi, Masayoshi [Department of Pathophysiological Science, Faculty of Pharmaceutical Science, Hokuriku University, Kanazawa (Japan); Ueda, Seiji; Fukami, Kei; Okuda, Seiya [Department of Medicine, Kurume University School of Medicine, Kurume (Japan)

    2010-07-23

    Research highlights: {yields} Nifedipine inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma}. {yields} GW9662 treatment alone increased RAGE mRNA levels in tubular cells. {yields} Nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-{kappa}B activation and increases in intercellular adhesion molecule-1 and transforming growth factor-{beta} gene expression in tubular cells, all of which were blocked by GW9662. -- Abstract: There is a growing body of evidence that advanced glycation end products (AGEs) and their receptor (RAGE) interaction evokes oxidative stress generation and subsequently elicits inflammatory and fibrogenic reactions, thereby contributing to the development and progression of diabetic nephropathy. We have previously found that nifedipine, a calcium-channel blocker (CCB), inhibits the AGE-induced mesangial cell damage in vitro. However, effects of nifedipine on proximal tubular cell injury remain unknown. We examined here whether and how nifedipine blocked the AGE-induced tubular cell damage. Nifedipine, but not amlodipine, a control CCB, inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}). GW9662 treatment alone was found to increase RAGE mRNA levels in tubular cells. Further, nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-{kappa}B activation and increases in intercellular adhesion molecule-1 and transforming growth factor-beta gene expression in tubular cells, all of which were blocked by GW9662. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-oxidative and anti-inflammatory agent against AGEs in tubular cells by suppressing RAGE expression

  19. Use of hydroxypropyl-beta-cyclodextrin ad polymer matrix for formation of inclusion complex with drug nifedipine

    International Nuclear Information System (INIS)

    Carneiro, Elisa F.; Araujo, Marcia V.G. de; Barbosa, Ronilson V.; Silva, Caroline W.P. da; Barisson, Andersson; Zawadzki, Sonia F.; Andrade, George Ricardo S.; Costa Junior, Nivan B. da

    2009-01-01

    In this work it was prepared and characterized an inclusion complex between the polymeric matrix hydroxypropyl-beta cyclodextrin and nifedipine, a hydrophobic drug calcium antagonistic, used for the cardiovascular diseases treatment. The study of the phase- solubility diagram showed an increase of the aqueous solubility of the drug after inclusion, was observed and The differential scanning calorimetry analysis did not show the melting point temperature of the drug in the formed complex. This fact is considered as an evidence of the encapsulation process. 1 H NMR studies suggested that the non-aromatic ring of the nifedipine would be inserted in the cavity of the hydroxypropyl-beta-cyclodextrin.This orientation was also proposed by the used molecular modelling methods. (author)

  20. Too slow, for Milton

    OpenAIRE

    Armstrong, N.

    2011-01-01

    Too slow, for Milton was written in 2011, as part of a memorial project for Milton Babbitt. The piece borrows harmonies from Babbitt's Composition for 12 Instruments (harmonies which Babbitt had in turn borrowed from Schoenberg's Ode to Napoleon), but unfolds them as part of a musical texture characterised by repetition, resonance, and a slow rate of change. As Babbitt once told me that my music was 'too slow', this seemed an appropriately obstinate form of homage.

  1. Film Coating of Nifedipine Extended Release Pellets in a Fluid Bed Coater with a Wurster Insert

    Directory of Open Access Journals (Sweden)

    Luciane Franquelin Gomes de Souza

    2014-01-01

    Full Text Available The objective of this work was to study the coating process of nifedipine extended release pellets using Opadry and Opadry II, in a fluid bed coater with a Wurster insert. The coating process was studied using a complete experimental design of two factors at two levels for each polymer. The variables studied were the inlet air temperature and the coating suspension flow rate. The agglomerate fraction and coating efficiency were the analyzed response variables. The air temperature was the variable that most influenced the coating efficiency for both polymers. In addition, a study of the dissolution profiles of coated and uncoated pellets using 0.5% sodium lauryl sulfate in simulated gastric fluid without enzymes (pH 1.2 was conducted. The results showed a prolonged release profile for the coated and uncoated pellets that was very similar to the standards established by the U.S. Pharmacopoeia. The drug content and the release profiles were not significantly affected by storage at 40°C and 75% relative humidity. However, when exposed to direct sunlight and fluorescent light (light from fluorescent bulbs, the coated pellets lost only 5% of the drug content, while the uncoated ones lost more than 35%; furthermore, the dissolution profile of the uncoated pellets was faster.

  2. Efficacy of resveratrol to supplement oral nifedipine treatment in pregnancy-induced preeclampsia

    Directory of Open Access Journals (Sweden)

    Jian Ding

    2017-10-01

    Full Text Available Objective: Preeclampsia (PE is a complication affecting pregnant women worldwide, which usually manifests as severe maternal hypertension. Resveratrol (RESV, a naturally existing polyphenol, is known to exhibit beneficial effects in cardiovascular disease including hypertension. We evaluated the outcome of treatment combining oral nifedipine (NIFE and RESV against PE. Design and methods: Using a randomized group assignment, 400 PE patients were enrolled and received oral treatments of either NIFE + RESV or NIFE + placebo. Primary endpoints were defined as time to control blood pressure and time before a new hypertensive crisis. Secondary endpoints were defined as the number of doses needed to control blood pressure, maternal and neonatal adverse effects. Results: Compared with the NIFE + placebo group, the time needed to control blood pressure was significantly reduced in NIFE + RESV group, while time before a new hypertensive crisis was greatly delayed in NIFE + RESV group. The number of treatment doses needed to control blood pressure was also categorically lower in NIFE + RESV group. No differences in maternal or neonatal adverse effects were observed between the two treatment groups. Conclusion: Our data support the potential of RESV as a safe and effective adjuvant of oral NIFE to attenuate hypertensive symptoms among PE patients.

  3. Development and characterization of nifedipine-amino methacrylate copolymer solid dispersion powders with various adsorbents

    Directory of Open Access Journals (Sweden)

    Yotsanan Weerapol

    2017-07-01

    Full Text Available Solid dispersions of nifedipine (NDP, a poorly water-soluble drug, and amino methacrylate copolymer (AMCP with aid of adsorbent, that is, fumed silica, talcum, calcium carbonate, titanium dioxide, and mesoporous silica from rice husks (SRH, were prepared by solvent method. The physicochemical properties of solid dispersions, compared to their physical mixtures, were determined using powder X-ray diffractometry (PXRD and differential scanning calorimetry (DSC. The surface morphology of the prepared solid dispersions was examined by scanning electron microscopy (SEM. The dissolution of NDP from solid dispersions was compared to NDP powders. The effect of adsorbent type on NDP dissolution was also examined. The dissolution of NDP increased with the ratio of NDP:AMCP:adsorbent of 1:4:1 when compared to the other formulations. As indicated from PXRD patterns, DSC thermograms and SEM images, NDP was molecularly dispersed within polymer carrier or in an amorphous form, which confirmed the better dissolution of solid dispersions. Solid dispersions containing SRH provided the highest NDP dissolution, due to a porous nature of SRH, allowing dissolved drug to fill in the pores and consequently dissolve in the medium. The results suggested that solid dispersions containing adsorbents (SRH in particular demonstrated improved dissolution of poorly water-soluble drug when compared to NDP powder.

  4. Film Coating of Nifedipine Extended Release Pellets in a Fluid Bed Coater with a Wurster Insert

    Science.gov (United States)

    de Souza, Luciane Franquelin Gomes; Nitz, Marcello; Taranto, Osvaldir Pereira

    2014-01-01

    The objective of this work was to study the coating process of nifedipine extended release pellets using Opadry and Opadry II, in a fluid bed coater with a Wurster insert. The coating process was studied using a complete experimental design of two factors at two levels for each polymer. The variables studied were the inlet air temperature and the coating suspension flow rate. The agglomerate fraction and coating efficiency were the analyzed response variables. The air temperature was the variable that most influenced the coating efficiency for both polymers. In addition, a study of the dissolution profiles of coated and uncoated pellets using 0.5% sodium lauryl sulfate in simulated gastric fluid without enzymes (pH 1.2) was conducted. The results showed a prolonged release profile for the coated and uncoated pellets that was very similar to the standards established by the U.S. Pharmacopoeia. The drug content and the release profiles were not significantly affected by storage at 40°C and 75% relative humidity. However, when exposed to direct sunlight and fluorescent light (light from fluorescent bulbs), the coated pellets lost only 5% of the drug content, while the uncoated ones lost more than 35%; furthermore, the dissolution profile of the uncoated pellets was faster. PMID:24772426

  5. Very slow neutrons

    International Nuclear Information System (INIS)

    Frank, A.

    1983-01-01

    The history is briefly presented of the research so far of very slow neutrons and their basic properties are explained. The methods are described of obtaining very slow neutrons and the problems of their preservation are discussed. The existence of very slow neutrons makes it possible to perform experiments which may deepen the knowledge of the fundamental properties of neutrons. Their wavelength approximates that of visible radiation. The possibilities and use are discussed of neutron optical systems (neutron microscope) which could be an effective instrument for the study of the detailed arrangement, especially of organic substances. (B.S.)

  6. Transformer Industry Productivity Slows.

    Science.gov (United States)

    Otto, Phyllis Flohr

    1981-01-01

    Annual productivity increases averaged 2.4 percent during 1963-79, slowing since 1972 to 1.5 percent; computer-assisted design and product standardization aided growth in output per employee-hour. (Author)

  7. Propanolol, Ciclosporine, Adryamicine, nifedipine and the in vitro labelling of red blood cells with 99mtechnetium

    International Nuclear Information System (INIS)

    Cardoso, V.N.; Diniz, S.O.F.; Roca, M.; Martin-Comin, J.

    2002-01-01

    Objectives: To evaluate the possible influence of Propanolol, Ciclosporine, Adryamicine and Nifedipine on the labelling in vitro of red blood cells. Materials And Methods: 20 ml of blood were withdrawn from 40 healthy volunteers that have not used drug seven days before of experiments. 2,0ml aliquots of each sample were incubated at 37 deg. C for 30 min with different concentrations of drugs to the two labelling method used. In the simple method 60ml of stannous chloride solution (10,2 m g/ml) were added and the samples centrifuged at 1000g for 5 min and plasma and blood cells were isolated. After that, 2,0ml of saline, 0,2 ml of EDTA (2,2%) and 7,4 MBq of 99m Tc were also added. To the hypochlorite method the blood samples were incubated with SnCl 2 (10,2m g/ml) for 5 min. After this period of time, 40ml of NaClO solution (1%) and all the reagents mentioned to simple method were added. The samples were centrifuged and labelling yield was calculated to both methods. Conclusions: The analysis of the results shows that using the two methods described there are no significant differences on the in vitro labelling of RBC with 99m Tc at the used concentrations of all of these studied drugs. We can speculate that the interferences observed in vivo may be due the presence of active metabolites or interactions among different drugs

  8. Effect of surfactant concentration on nifedipine crystal habit and its related pharmaceutical properties

    Science.gov (United States)

    Kumar, Dinesh; Thipparaboina, Rajesh; Modi, Sameer R.; Bansal, Arvind K.; Shastri, Nalini R.

    2015-07-01

    Crystallization in the presence of Polysorbate-80 (T-80), a non-ionic surfactant was explored for crystal habit modification of nifedipine polymorph I (Nif). A concentration dependent reduction in aspect ratio was observed with T-80. Generation of any new solvates/polymorphs was ruled out by Fourier Transform Infrared spectroscopy, differential scanning calorimetry, powder X-ray diffraction, and thermogravimetric analysis, while the absence of T-80 on the surface or bulk of the recrystallized samples was established by liquid chromatography mass spectroscopy. The dissolution rate order of the re-crystallized Nif habits was in the order of; Nif-D (Nif with 0.6%v/v T-80)>Nif-C (Nif with 0.4% v/v T-80)>Nif-B (Nif with 0.2% v/v T-80)>Nif-A (plain Nif). Wetting ability and surface free energy determination from contact angle measurements were used to explain the order of dissolution rate. The consequences of varying concentration of T-80 on Nif crystal habit was supported by means of molecular dynamics (MD) which was executed using COMPASS force field while modified attachment energy was computed to acquire the absolute morphology. The mechanism for alteration in the morphology was suggested based on the computed crystal surface chemistry. Nif-D crystal habit was nearly iso-diametric with majority of facets occupied by polar dominant surfaces {0 1 1} and {0 0 2} which ultimately resulted in higher dissolution rate. In Nif-B and Nif-C the dissolution rate was dependent on the proportion of polar and non-polar facet area. The methodology used in this study could be an influential tool for selection of concentration of habit-modifying additives in other crystallization studies.

  9. Peritoneal clearances in hypertensive CAPD patients after oral administration of clonidine, enalapril, and nifedipine.

    Science.gov (United States)

    Favazza, A; Motanaro, D; Messa, P; Antonucci, F; Gropuzzo, M; Mioni, G

    1992-01-01

    The authors investigated whether the reduction of arterial pressure, induced by the oral administration of clonidine (CLO), enalapril (EN), and nifedipine (NIF), has any effect on peritoneal transport rates. The study was performed in nine hypertensive patients undergoing continuous ambulatory peritoneal dialysis (CAPD). The patients were submitted to administration of CLO, EN, and NIF, each in randomized succession for two weeks, after withdrawal of any hypotensive therapy for eight days (washout period). The nine patients underwent a four-hour dwell exchange using a 2.27 g/dL glucose two-liter bag after washout and after each hypotensive period. The following parameters were analyzed: mean arterial pressure (MAP), performed in the sitting position; net ultrafiltration; effluent/initial dialysate glucose ratio (GL D/Do); peritoneal clearance of K, BUN, creatinine (Cr), phosphate, beta-2 microglobulin (beta 2), total proteins, and the ratio between beta 2 and Cr clearance. Moreover, residual renal Cr and beta 2 clearances were analyzed. The three drugs significantly reduced MAP at a similar rate. The peritoneal transport parameters after CLO were similar to the results in the washout period. On the contrary, after EN and NIF therapy, Cr and beta 2 clearances were significantly increased, and GL D/Do decreased in comparison to the washout period. The other peritoneal transport parameters after EN and NIF were similar to the washout period. Residual renal Cr and beta 2 clearances after the three drugs were similar to those in the washout. these data suggest that after two weeks of therapy with EN and NIF, glucose, Cr, and beta 2 peritoneal transports are influenced by these hypotensive drugs irrespective of the effect on the arterial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Direct NMR Monitoring of Phase Separation Behavior of Highly Supersaturated Nifedipine Solution Stabilized with Hypromellose Derivatives.

    Science.gov (United States)

    Ueda, Keisuke; Higashi, Kenjirou; Moribe, Kunikazu

    2017-07-03

    We investigated the phase separation behavior and maintenance mechanism of the supersaturated state of poorly water-soluble nifedipine (NIF) in hypromellose (HPMC) derivative solutions. Highly supersaturated NIF formed NIF-rich nanodroplets through phase separation from aqueous solution containing HPMC derivative. Dissolvable NIF concentration in the bulk water phase was limited by the phase separation of NIF from the aqueous solution. HPMC derivatives stabilized the NIF-rich nanodroplets and maintained the NIF supersaturation with phase-separated NIF for several hours. The size of the NIF-rich phase was different depending on the HPMC derivatives dissolved in aqueous solution, although the droplet size had no correlation with the time for which NIF supersaturation was maintained without NIF crystallization. HPMC acetate and HPMC acetate succinate (HPMC-AS) effectively maintained the NIF supersaturation containing phase-separated NIF compared with HPMC. Furthermore, HPMC-AS stabilized NIF supersaturation more effectively in acidic conditions. Solution 1 H NMR measurements of NIF-supersaturated solution revealed that HPMC derivatives distributed into the NIF-rich phase during the phase separation of NIF from the aqueous solution. The hydrophobicity of HPMC derivative strongly affected its distribution into the NIF-rich phase. Moreover, the distribution of HPMC-AS into the NIF-rich phase was promoted at lower pH due to the lower aqueous solubility of HPMC-AS. The distribution of a large amount of HPMC derivatives into NIF-rich phase induced the strong inhibition of NIF crystallization from the NIF-rich phase. Polymer distribution into the drug-rich phase directly monitored by solution NMR technique can be a useful index for the stabilization efficiency of drug-supersaturated solution containing a drug-rich phase.

  11. Comparison of antianginal efficacy of nifedipine and isosorbide dinitrate in chronic stable angina: a long-term, randomized, double-blind, crossover study

    International Nuclear Information System (INIS)

    Liang, C.S.; Coplin, B.; Wellington, K.

    1985-01-01

    Using a double-blind, crossover design, the comparative efficacy and safety of nifedipine and isosorbide dinitrate in the treatment of stable angina were studied in 34 patients. The study included a 2-week placebo washout period and two 6-week periods during which patients were randomized to either nifedipine or isosorbide dinitrate. The doses were titrated for each patient, and mean doses of the 2 drugs were comparable. A time-limited thallium treadmill test was performed at the end of each phase. Ischemic zone count rates were normalized to those of the nonischemic zone, and the change in this ratio with redistribution was calculated as reversible thallium defect. Two patients were discontinued from the study within 1 week after initiation of isosorbide dinitrate because of severe, intolerable headache. Two patients were withdrawn while receiving nifedipine: one had new congestive heart failure and the other had increasing angina. Of the remaining 30 patients who tolerated both drugs for at least 1 week, 4 patients from the isosorbide dinitrate group were either prematurely crossed over or discontinued from the study because of headache. One patient suffered headache from both drugs and was discontinued from the study. In the 30 patients, only nifedipine significantly reduced resting arterial pressure compared with baseline. Further, only nifedipine therapy resulted in significant decreases in the rate-pressure product and systolic pressure at a given workload. However, significant decreases in angina frequency, nitroglycerin consumption and exercise-induced maximum ST-segment depression and reversible thallium perfusion defect were produced by both nifedipine and isosorbide dinitrate

  12. Combination therapy with metoprolol and nifedipine versus monotherapy in patients with stable angina pectoris. Results of the International Multicenter Angina Exercise (IMAGE) Study

    DEFF Research Database (Denmark)

    Savonitto, S; Ardissiono, D; Egstrup, K

    1996-01-01

    was then added for a further 4 weeks. Exercise tests were performed at weeks 0, 6 and 10. RESULTS: At week 6, both metoprolol and nifedipine increased the mean exercise time to 1-mm ST segment depression in comparison with week 0 (both p ... 10, the groups randomized to combination therapy had a further increase in time to 1-mm ST segment depression (p ... metoprolol to nifedipine showed an increase in exercise tolerance that was greater than the 90th percentile of the distribution of the changes observed in the corresponding monotherapy + placebo groups. However, among these patients, an additive effect was observed only in 1 (14%) of the 7 patients treated...

  13. SPS slow extraction septa

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    SPS long straight section (LSS) with a series of 5 septum tanks for slow extraction (view in the direction of the proton beam). There are 2 of these: in LSS2, towards the N-Area; in LSS6 towards the W-Area. See also Annual Report 1975, p.175.

  14. AGS slow extraction improvements

    International Nuclear Information System (INIS)

    Glenn, J.W.; Smith, G.A.; Sandberg, J.N.; Repeta, L.; Weisberg, H.

    1979-01-01

    Improvement of the straightness of the F5 copper septum increased the AGS slow extraction efficiency from approx. 80% to approx. 90%. Installation of an electrostatic septum at H2O, 24 betatron wavelengths upstream of F5, further improved the extraction efficiency to approx. 97%

  15. PF slow positron source

    International Nuclear Information System (INIS)

    Shirakawa, A.; Enomoto, A.; Kurihara, T.

    1993-01-01

    A new slow-positron source is under construction at the Photon Factory. Positrons are produced by bombarding a tantalum rod with high-energy electrons; they are moderated in multiple tungsten vanes. We report here the present status of this project. (author)

  16. Use of drug therapy in the management of symptomatic ureteric stones in hospitalised adults: a multicentre, placebo-controlled, randomised controlled trial and cost-effectiveness analysis of a calcium channel blocker (nifedipine) and an alpha-blocker (tamsulosin) (the SUSPEND trial).

    Science.gov (United States)

    Pickard, Robert; Starr, Kathryn; MacLennan, Graeme; Kilonzo, Mary; Lam, Thomas; Thomas, Ruth; Burr, Jennifer; Norrie, John; McPherson, Gladys; McDonald, Alison; Shearer, Kirsty; Gillies, Katie; Anson, Kenneth; Boachie, Charles; N'Dow, James; Burgess, Neil; Clark, Terry; Cameron, Sarah; McClinton, Samuel

    2015-08-01

    Ureteric colic, the term used to describe the pain felt when a stone passes down the ureter from the kidney to the bladder, is a frequent reason for people to seek emergency health care. Treatment with the muscle-relaxant drugs tamsulosin hydrochloride (Petyme, TEVA UK Ltd) and nifedipine (Coracten(®), UCB Pharma Ltd) as medical expulsive therapy (MET) is increasingly being used to improve the likelihood of spontaneous stone passage and lessen the need for interventional procedures. However, there remains considerable uncertainty around the effectiveness of these drugs for routine use. To determine whether or not treatment with either tamsulosin 400 µg or nifedipine 30 mg for up to 4 weeks increases the rate of spontaneous stone passage for people with ureteric colic compared with placebo, and whether or not it is cost-effective for the UK NHS. A pragmatic, randomised controlled trial comparing two active drugs, tamsulosin and nifedipine, against placebo. Participants, clinicians and trial staff were blinded to treatment allocation. A cost-utility analysis was performed using data gathered during trial participation. Urology departments in 24 UK NHS hospitals. Adults aged between 18 and 65 years admitted as an emergency with a single ureteric stone measuring ≤ 10 mm, localised by computerised tomography, who were able to take trial medications and complete trial procedures. Eligible participants were randomised 1 : 1 : 1 to take tamsulosin 400 µg, nifedipine 30 mg or placebo once daily for up to 4 weeks to make the following comparisons: tamsulosin or nifedipine (MET) versus placebo and tamsulosin versus nifedipine. The primary effectiveness outcome was the proportion of participants who spontaneously passed their stone. This was defined as the lack of need for active intervention for ureteric stones at up to 4 weeks after randomisation. This was determined from 4- and 12-week case-report forms completed by research staff, and from the 4

  17. The effect of pertussis toxin (PTX) treatment on blood pressure (BP), norepinephrine pressor responsiveness and BP response to acute nifedipine administration in genetic hypertension

    Czech Academy of Sciences Publication Activity Database

    Zicha, Josef; Pintérová, Mária; Dobešová, Zdenka; Líšková, Silvia; Kuneš, Jaroslav

    2006-01-01

    Roč. 48, č. 4 (2006), s. 773-774 ISSN 0194-911X. [Annual Meeting of the European Council for Cardiovascular Research (ECCR) /11./. 29.09.2006-01.10.2006, La Colle sur Loup] R&D Projects: GA MZd(CZ) NR7786 Keywords : pertussis toxin * blood pressure * norepinephrine * nifedipine Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery

  18. Slow wave cyclotron maser

    International Nuclear Information System (INIS)

    Kho, T.H.; Lin, A.T.

    1988-01-01

    Cyclotron masers such as Gyrotrons and the Autoresonance Masers, are fast wave devices: the electromagnetic wave's phase velocity v rho , is greater than the electron beam velocity, v b . To be able to convert the beam kinetic energy into radiation in these devices the beam must have an initial transverse momentum, usually obtained by propagating the beam through a transverse wiggler magnet, or along a nonuniform guide magnetic field before entry into the interaction region. Either process introduces a significant amount of thermal spread in the beam which degrades the performance of the maser. However, if the wave phase velocity v rho v b , the beam kinetic energy can be converted directly into radiation without the requirement of an initial transverse beam momentum, making a slow wave cyclotron maser a potentially simpler and more compact device. The authors present the linear and nonlinear physics of the slow wave cyclotron maser and examine its potential for practical application

  19. Slow-transit Constipation.

    Science.gov (United States)

    Bharucha, Adil E.; Philips, Sidney F.

    2001-08-01

    Idiopathic slow-transit constipation is a clinical syndrome predominantly affecting women, characterized by intractable constipation and delayed colonic transit. This syndrome is attributed to disordered colonic motor function. The disorder spans a spectrum of variable severity, ranging from patients who have relatively mild delays in transit but are otherwise indistinguishable from irritable bowel syndrome to patients with colonic inertia or chronic megacolon. The diagnosis is made after excluding colonic obstruction, metabolic disorders (hypothyroidism, hypercalcemia), drug-induced constipation, and pelvic floor dysfunction (as discussed by Wald ). Most patients are treated with one or more pharmacologic agents, including dietary fiber supplementation, saline laxatives (milk of magnesia), osmotic agents (lactulose, sorbitol, and polyethylene glycol 3350), and stimulant laxatives (bisacodyl and glycerol). A subtotal colectomy is effective and occasionally is indicated for patients with medically refractory, severe slow-transit constipation, provided pelvic floor dysfunction has been excluded or treated.

  20. A Simple Slow-Sand Filter for Drinking Water Purification

    Directory of Open Access Journals (Sweden)

    K. O. Yusuf

    2017-04-01

    Full Text Available Water-borne diseases are commonly encountered when pathogen-contaminated water is consumed. In rural areas, water is usually obtained from ponds, open shallow wells, streams and rain water during rainy season. Rain water is often contaminated by pathogens due to unhygienic of physical and chemical conditions of the roofs thereby making it unsafe for consumption. A simple slow sand filter mechanism was designed and fabricated for purification of water in rural areas where electricity is not available to power water purification devices. Rain water samples were collected from aluminum roof, galvanized roof and thatched roof. The waters samples were allowed to flow through the slow sand filter. The values of turbidity, total dissolved solids, calcium, nitrite, faecal coliform and total coliform from unfiltered water through thatched roof were 0.92 NTU, 27.23 mg/l, 6 mg/l, 0.16 mg/l, 5cfu/100ml and 6.0 cfu/100ml, respectively while the corresponding values for slow sand filter from thatched roof were 0.01 NTU, 0.23 mg/l, 2.5 mg/l, 0.1 mg/l, 0 cfu/100ml and 0 cfu/100ml, respectively. The values of turbidity, total dissolved solid, nitrite, calcium, faecal coliform and total coliform from unfiltered water for aluminum roof were 0.82 NTU, 23.68 mg/l, 2.70 mg/l, 1.0 mg/l, 4 cfu/100ml and 4cfu/100ml, respectively while the corresponding values for slow sand filter were 0.01 NTU, 0.16 mg/l, 0.57 mg/l, 0.2 mg/l, 0 cfu/100ml and 0 cfu/100ml, respectively. The values obtained for galvanized roof were also satisfactory. The slow sand filter is recommended for used in rural areas for water purification to prevent risk of water-borne diseases.

  1. Evaluation of 89 compounds for identification of substrates for cynomolgus monkey CYP2C76, a new bupropion/nifedipine oxidase.

    Science.gov (United States)

    Hosaka, Shinya; Murayama, Norie; Satsukawa, Masahiro; Shimizu, Makiko; Uehara, Shotaro; Fujino, Hideki; Iwasaki, Kazuhide; Iwano, Shunsuke; Uno, Yasuhiro; Yamazaki, Hiroshi

    2015-01-01

    Cynomolgus monkeys are widely used in preclinical studies during drug development because of their evolutionary closeness to humans, including their cytochrome P450s (P450s). Most cynomolgus monkey P450s are almost identical (≥90%) to human P450s; however, CYP2C76 has low sequence identity (approximately 80%) to any human CYP2Cs. Although CYP2C76 has no ortholog in humans and is partly responsible for species differences in drug metabolism between cynomolgus monkeys and humans, a broad evaluation of potential substrates for CYP2C76 has not yet been conducted. In this study, a screening of 89 marketed compounds, including human CYP2C and non-CYP2C substrates or inhibitors, was conducted to find potential CYP2C76 substrates. Among the compounds screened, 19 chemicals were identified as substrates for CYP2C76, including substrates for human CYP1A2 (7-ethoxyresorufin), CYP2B6 (bupropion), CYP2D6 (dextromethorphan), and CYP3A4/5 (dextromethorphan and nifedipine), and inhibitors for CYP2B6 (sertraline, clopidogrel, and ticlopidine), CYP2C8 (quercetin), CYP2C19 (ticlopidine and nootkatone), and CYP3A4/5 (troleandomycin). CYP2C76 metabolized a wide variety of the compounds with diverse structures. Among them, bupropion and nifedipine showed high selectivity to CYP2C76. As for nifedipine, CYP2C76 formed methylhydroxylated nifedipine, which was not produced by monkey CYP2C9, CYP2C19, or CYP3A4, as identified by mass spectrometry and estimated by a molecular docking simulation. This unique oxidative metabolite formation of nifedipine could be one of the selective marker reactions of CYP2C76 among the major CYP2Cs and CYP3As tested. These results suggest that monkey CYP2C76 contributes to bupropion hydroxylation and formation of different nifedipine oxidative metabolites as a result of its relatively large substrate cavity. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

  2. Nifedipine, a calcium channel blocker, inhibits advanced glycation end product (AGE)-elicited mesangial cell damage by suppressing AGE receptor (RAGE) expression via peroxisome proliferator-activated receptor-gamma activation

    International Nuclear Information System (INIS)

    Matsui, Takanori; Yamagishi, Sho-ichi; Takeuchi, Masayoshi; Ueda, Seiji; Fukami, Kei; Okuda, Seiya

    2009-01-01

    The interaction between advanced glycation end products (AGE) and their receptor RAGE mediates the progressive alteration in renal architecture and loss of renal function in diabetic nephropathy. Oxidative stress generation and inflammation also play a central role in diabetic nephropathy. This study investigated whether and how nifedipine, a calcium channel blocker (CCB), blocked the AGE-elicited mesangial cell damage in vitro. Nifedipine, but not amlodipine, a control CCB, down-regulated RAGE mRNA levels and subsequently reduced reactive oxygen species (ROS) generation in AGE-exposed mesangial cells. AGE increased mRNA levels of vascular cell adhesion molecule-1 (VCAM-1) and induced monocyte chemoattractant protein-1 (MCP-1) production in mesangial cells, both of which were prevented by the treatment with nifedipine, but not amlodipine. The beneficial effects of nifedipine on AGE-exposed mesangial cells were blocked by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-γ (PPAR-γ). Although nifedipine did not affect expression levels of PPAR-γ, it increased the PPAR-γ transcriptional activity in mesangial cells. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-inflammatory agent against AGE by suppressing RAGE expression in cultured mesangial cells via PPAR-γ activation.

  3. Epigallocatechin gallate enhances treatment efficacy of oral nifedipine against pregnancy-induced severe pre-eclampsia: A double-blind, randomized and placebo-controlled clinical study.

    Science.gov (United States)

    Shi, D-D; Guo, J-J; Zhou, L; Wang, N

    2018-02-01

    Oral nifedipine is commonly used to treat pre-eclampsia, one of the most severe complications during pregnancy, but its clinical efficacy is less than ideal. Epigallocatechin gallate (EGCG), a natural compound from green tea, could benefit cardiovascular health especially hypertension. We investigated the clinical efficacy of EGCG, when complemented with oral nifedipine, in treating pre-eclampsia. A total of 350 pregnant women with severe pre-eclampsia were recruited and randomized to receive oral nifedipine, together with placebo (NIF+placebo) or EGCG (NIF+EGCG). The primary treatment outcome was the time needed to control blood pressure and interval time before a new hypertensive crisis, whereas the secondary treatment outcome was the number of treatment doses to effectively control blood pressure, maternal adverse effects and neonatal complications. Comparing NIF+EGCG group to NIF+placebo group, the time needed to control blood pressure was significantly shorter (NIF+EGCG 31.2±16.7 minutes, NIF+placebo 45.3±21.9 minutes; 95% CI 9.7-18.5 minutes), whereas interval time before a new hypertensive crisis was significantly prolonged (NIF+EGCG 7.2±2.9 hours, NIF+placebo 4.1±3.7 hours; 95% CI 2.3-3.9 hours), and the number of treatment dosages needed to effectively control blood pressure was also lower. Between the two treatment groups, no differences in incidence rates of maternal adverse effects or neonatal complications were observed. EGCG is both safe and effective in enhancing treatment efficacy of oral nifedipine against pregnancy-induced severe pre-eclampsia, but formal validation is required prior to its recommendation for use outside of clinical trials. © 2017 John Wiley & Sons Ltd.

  4. The influence of nifedipine and pertussis toxin (PTX) on vascular responsiveness to alpha1- and alpha2-adrenergic stimulation of isolated femoral arteries

    Czech Academy of Sciences Publication Activity Database

    Líšková, Silvia; Kuneš, Jaroslav; Paulis, Ĺudovít; Zicha, Josef

    2006-01-01

    Roč. 48, č. 4 (2006), s. 769-769 ISSN 0194-911X. [Annual Meeting of the European Council for Cardiovascular Research (ECCR) /11./. 29.09.2006-01.10.2006, La Colle sur Loup] R&D Projects: GA MZd NR7786 Institutional research plan: CEZ:AV0Z50110509 Keywords : nifedipine * pertussis toxin * vascular responsiveness * alpha1- and alpha2-adrenergic stimulation * femorel arteria Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery

  5. Microalbuminuria and sRAGE in High-Risk Hypertensive Patients Treated with Nifedipine/Telmisartan Combination Treatment: A Substudy of TALENT

    Directory of Open Access Journals (Sweden)

    Colomba Falcone

    2012-01-01

    Full Text Available Some antihypertensive drugs have also renoprotective and anti-inflammatory properties that go beyond their effect on blood pressure. It has been suggested that microalbuminuria and glomerular filtration rate (GFR are associated with circulating levels of the soluble form of the receptor, sRAGE (soluble receptor for advanced glycation ends-products. In the present analysis, we used data from the TALENT study to evaluate soluble receptor for advanced glycation end-products (sRAGE plasma levels in patients with hypertension and high-cardiovascular risk-treated nifedipine and telmisartan in combination. Treatment with nifedipine-telmisartan significantly decreased mean systolic and diastolic ambulatory blood pressure and resulted in a significant increase in sRAGE plasma concentrations after 24 weeks of therapy. We concluded that in hypertensive patients with early-stage renal disease, sRAGE concentrations are not influenced by either microalbuminuria or GFR. Long-term treatment with a combination of nifedipine-telmisartan may have a beneficial effect increasing sRAGE plasma levels, thus exerting an atheroprotective and anti-inflammatory activity.

  6. Clinical case report of long-term follow-up in type-2 diabetes patient with severe chronic periodontitis and nifedipine-induced gingival overgrowth.

    Science.gov (United States)

    Shibukawa, Yoshihiro; Fujinami, Koushu; Yamashita, Shuichiro

    2012-01-01

    In this case report, we describe the clinical course over a 14-year follow-up in a 47-year-old diabetes patient with severe chronic periodontitis and nifedipine-induced gingival overgrowth. The patient had a history of hypertension for over 5 years and uncontrolled type 2 diabetes. Overgrown gingiva was observed in most of the teeth and was marked in the upper and lower anterior teeth. A probing pocket depth of ≥ 4 mm and bleeding on probing (BOP) were observed in 94 and 90% of sites examined, respectively. At baseline, his hemoglobin A1c (HbA1c) was 8.5%. The patient received periodontal and diabetic treatment simultaneously. Medication was changed from nifedipine chloride to an angiotensin-converting enzyme inhibitor. After initial therapy and subsequent periodontal surgery, gingival overgrowth disappeared and probing depth and BOP showed a significant improvement. No recurrence was observed during supportive periodontal therapy (SPT). The HbA1c level improved from 8.5 to 6.3% after periodontal treatment, subsequently remaining at a good level during SPT over 10 years. This study demonstrated that periodontal treatment, withdrawal of medication and control of diabetes can result in remarkable improvements in type 2 diabetes patients with chronic periodontitis and nifedipine-induced gingival overgrowth. These results suggest that comprehensive periodontal treatment in combination with treatment for diabetes mellitus can exert a positive influence on blood glucose levels and periodontal condition in diabetic patients.

  7. Coaxial slow source

    International Nuclear Information System (INIS)

    Brooks, R.D.; Jarboe, T.R.

    1990-01-01

    Field reversed configurations (FRCs) are a class of compact toroid with not toroidal field. The field reversed theta pinch technique has been successfully used for formation of FRCs since their inception in 1958. In this method an initial bias field is produced. After ionization of the fill gas, the current in the coil is rapidly reversed producing the radial implosion of a current sheath. At the ends of the coil the reversed field lines rapidly tear and reconnect with the bias field lines until no more bias flux remains. At this point, vacuum reversed field accumulates around the configuration which contracts axially until an equilibrium is reached. When extrapolating the use of such a technique to reactor size plasmas two main shortcomings are found. First, the initial bias field, and hence flux in a given device, which can be reconnected to form the configuration is limited from above by destructive axial dynamics. Second, the voltages required to produce rapid current reversal in the coil are very large. Clearly, a low voltage formation technique without limitations on flux addition is desirable. The Coaxial Slow Source (CSS) device was designed to meet this need. It has two coaxial theta pinch coils. Coaxial coil geometry allows for the addition of as much magnetic flux to the annular plasma between them as can be generated inside the inner coil. Furthermore the device can be operated at charging voltages less than 10 kV and on resistive diffusion, rather than implosive time scales. The inner coil is a novel, concentric, helical design so as to allow it to be cantilevered on one end to permit translation of the plasma. Following translation off the inner coil the Annular Field Reversed Configuration would be re-formed as a true FRC. In this paper we investigate the formation process in the new parallel configuration., CSSP, in which the inner and outer coils are connected in parallel to the main capacitor bank

  8. Slow Tourism: Exploring the discourses

    Directory of Open Access Journals (Sweden)

    J. Guiver

    2016-05-01

    Full Text Available ‘Slow travel’ and ‘slow tourism’ are relatively new, but contested, concepts. This paper examines the meanings ascribed to them in the academic literature and websites targeted at potential tourists. It finds concurrence on aspects of savouring time at the destination and investing time to appreciate the locality, its people, history, culture and products, but detects different emphases. The academic literature stresses the benefits to the destination and global sustainability, while the websites focus on the personal benefits and ways of becoming a ‘slow tourist’. Food and drink epitomise the immersion in and absorption of the destination and the multi-dimensional tourism experience, contrasted with the superficiality of mainstream tourism. The paper discusses whether tourists practising slow tourism without using the label are slow tourists or not.

  9. DEVELOPMENT OF ORAL NIFEDIPINE-LOADED POLYMERIC NANOCAPSULES: PHYSICOCHEMICAL CHARACTERISATION, PHOTOSTABILITY STUDIES, IN VITRO AND IN VIVO EVALUATION

    Directory of Open Access Journals (Sweden)

    Monika Piazzon Tagliari

    2015-07-01

    Full Text Available In this study, nifedipine (NFP-loaded polymeric nanocapsules were prepared and characterised with a view to protect the drug from degradation. Nanocapsule suspensions were prepared using two different surfactants (pluronic F68 and polyvinyl alcohol. Physicochemical stability and in vivoantihypertensive effect were evaluated. The particle size, zeta potential and entrapment efficiency remained constant during a period of 28 days of exposure under light irradiation. A smaller particle size and a higher zeta potential were obtained for the nanocapsules prepared with Pluronic F68 as surfactant. The solid drug and the nanocapsules were submitted to light exposure for 28 days. After this period of time, the percentage of drug remaining in the PF68NFP and PVANFP nanocapsules was 28.1% and 21.3%, respectively. In contrast, the solid drug was completely degraded after 4 days, suggesting that the nanocapsule suspensions promoted significant protection of the drug against light exposure. In addition, in vivo studies were carried out, which demonstrated that the formulations with polyvinyl alcohol exhibited a very rapid onset of action after oral administration in rats and led to faster drug release. The nanoparticles developed can be considered as an alternative for improving NFP stability in liquid formulations.

  10. Slow light in moving media

    Science.gov (United States)

    Leonhardt, U.; Piwnicki, P.

    2001-06-01

    We review the theory of light propagation in moving media with extremely low group velocity. We intend to clarify the most elementary features of monochromatic slow light in a moving medium and, whenever possible, to give an instructive simplified picture.

  11. Birth control - slow release methods

    Science.gov (United States)

    Contraception - slow-release hormonal methods; Progestin implants; Progestin injections; Skin patch; Vaginal ring ... might want to consider a different birth control method. SKIN PATCH The skin patch is placed on ...

  12. Slow rupture of frictional interfaces

    OpenAIRE

    Sinai, Yohai Bar; Brener, Efim A.; Bouchbinder, Eran

    2011-01-01

    The failure of frictional interfaces and the spatiotemporal structures that accompany it are central to a wide range of geophysical, physical and engineering systems. Recent geophysical and laboratory observations indicated that interfacial failure can be mediated by slow slip rupture phenomena which are distinct from ordinary, earthquake-like, fast rupture. These discoveries have influenced the way we think about frictional motion, yet the nature and properties of slow rupture are not comple...

  13. Rheology Guided Rational Selection of Processing Temperature To Prepare Copovidone-Nifedipine Amorphous Solid Dispersions via Hot Melt Extrusion (HME).

    Science.gov (United States)

    Yang, Fengyuan; Su, Yongchao; Zhang, Jingtao; DiNunzio, James; Leone, Anthony; Huang, Chengbin; Brown, Chad D

    2016-10-03

    The production of amorphous solid dispersions via hot melt extrusion (HME) relies on elevated temperature and prolonged residence time, which can result in potential degradation and decomposition of thermally sensitive components. Herein, the rheological properties of a physical mixture of polymer and an active pharmaceutical ingredient (API) were utilized to guide the selection of appropriate HME processing temperature. In the currently studied copovidone-nifedipine system, a critical temperature, which is substantially lower (∼13 °C) than the melting point of crystalline API, was captured during a temperature ramp examination and regarded as the critical point at which the API could molecularly dissolve into the polymer. Based on the identification of this critical point, various solid dispersions were prepared by HME processing below, at, and above the critical temperature (both below and above the melting temperature (T m ) of crystalline API). In addition, the resultant extrudates along with two control solid dispersions prepared by physical mixing and cryogenic milling were assessed by X-ray diffraction, differential scanning calorimetry, hot stage microscopy, rheology, and solid-state NMR. Physicochemical properties of resultant solid dispersions indicated that the identified critical temperature is sufficient for the polymer-API system to reach a molecular-level mixing, manifested by the transparent and smooth appearance of extrudates, the absence of API crystalline diffraction and melting peaks, dramatically decreased rheological properties, and significantly improved polymer-API miscibility. Once the critical temperature has been achieved, further raising the processing temperature only results in limited improvement of API dispersion, reflected by slightly reduced storage modulus and complex viscosity and limited improvement in miscibility.

  14. Sex difference in induction of hepatic CYP2B and CYP3A subfamily enzymes by nicardipine and nifedipine in rats

    International Nuclear Information System (INIS)

    Konno, Yoshihiro; Sekimoto, Masashi; Nemoto, Kiyomitsu; Degawa, Masakuni

    2004-01-01

    Male and female of F344 rats were treated per os with nicardipine (Nic) and nifedipine (Nif), and changes in the levels of mRNA and protein of hepatic cytochrome P450 (P450) enzymes, CYP2B1, CYP2B2, CYP3A1, CYP3A2, CYP3A9, and CYP3A18 were examined. Furthermore, hepatic microsomal activities for pentoxyresorufin O-dealkylation (PROD) and nifedipine oxidation, which are mainly mediated by CYP2B and CYP3A subfamily enzymes, respectively, were measured. Analyses of RT-PCR and Western blotting revealed that Nic and Nif induced predominantly CYP3A and CYP2B enzymes, respectively. As for the gene activation of CYP2B enzymes, especially CYP2B1, Nif showed high capacity in both sexes of rats, whereas Nic did a definite capacity in the males but little in the females. Gene activations of CYP3A1, CYP3A2, and CYP3A18 by Nic occurred in both sexes of rats, although that of CYP3A9 did only in the male rats. Although gene activations of CYP3A1 and CYP3A2 by Nif were observed in both sexes of rats, a slight activation of the CYP3A9 gene occurred only in female rats, and the CYP3A18 gene activation, in neither male nor female rats. Thus, changes in levels of the mRNA or protein of CYP2B and CYP3A enzymes, especially CYP2B1 and CYP3A2, were closely correlated with those in hepatic PROD and nifedipine oxidation activities, respectively. The present findings demonstrate for the first time the sex difference in the Nic- and Nif-mediated induction of hepatic P450 enzymes in rats and further indicate that Nic and Nif show different specificities and sex dependencies in the induction of hepatic P450 enzymes

  15. The Potential of/for 'Slow': Slow Tourists and Slow Destinations

    Directory of Open Access Journals (Sweden)

    J. Guiver

    2016-05-01

    Full Text Available Slow tourism practices are nothing new; in fact, they were once the norm and still are for millions of people whose annual holiday is spent camping, staying in caravans, rented accommodation, with friends and relations or perhaps in a second home, who immerse themselves in their holiday environment, eat local food, drink local wine and walk or cycle around the area. So why a special edition about slow tourism? Like many aspects of life once considered normal (such as organic farming or free-range eggs, the emergence of new practices has highlighted differences and prompted a re-evaluation of once accepted practices and values. In this way, the concept of ‘slow tourism’ has recently appeared as a type of tourism that contrasts with many contemporary mainstream tourism practices. It has also been associated with similar trends already ‘branded’ slow: slow food and cittaslow (slow towns and concepts such as mindfulness, savouring and well-being.

  16. Slow, stopped and stored light

    International Nuclear Information System (INIS)

    Welch, G.; Scully, M.

    2005-01-01

    Light that can been slowed to walking pace could have applications in telecommunications, optical storage and quantum computing. Whether we use it to estimate how far away a thunderstorm is, or simply take it for granted that we can have a conversation with someone on the other side of the world, we all know that light travels extremely fast. Indeed, special relativity teaches us that nothing in the universe can ever move faster than the speed of light in a vacuum: 299 792 458 ms sup - sup 1. However, there is no such limitation on how slowly light can travel. For the last few years, researchers have been routinely slowing light to just a few metres per second, and have recently even stopped it dead in its tracks so that it can be stored for future use. Slow-light has considerable popular appeal, deriving perhaps from the importance of the speed of light in relativity and cosmology. If everyday objects such as cars or people can travel faster than 'slow' light, for example, then it might appear that relativistic effects could be observed at very low speeds. Although this is not the case, slow light nonetheless promises to play an important role in optical technology because it allows light to be delayed for any period of time desired. This could lead to all-optical routers that would increase the bandwidth of the Internet, and applications in optical data storage, quantum information and even radar. (U.K.)

  17. Slow rupture of frictional interfaces

    Science.gov (United States)

    Bar Sinai, Yohai; Brener, Efim A.; Bouchbinder, Eran

    2012-02-01

    The failure of frictional interfaces and the spatiotemporal structures that accompany it are central to a wide range of geophysical, physical and engineering systems. Recent geophysical and laboratory observations indicated that interfacial failure can be mediated by slow slip rupture phenomena which are distinct from ordinary, earthquake-like, fast rupture. These discoveries have influenced the way we think about frictional motion, yet the nature and properties of slow rupture are not completely understood. We show that slow rupture is an intrinsic and robust property of simple non-monotonic rate-and-state friction laws. It is associated with a new velocity scale cmin, determined by the friction law, below which steady state rupture cannot propagate. We further show that rupture can occur in a continuum of states, spanning a wide range of velocities from cmin to elastic wave-speeds, and predict different properties for slow rupture and ordinary fast rupture. Our results are qualitatively consistent with recent high-resolution laboratory experiments and may provide a theoretical framework for understanding slow rupture phenomena along frictional interfaces.

  18. Slow Images and Entangled Photons

    International Nuclear Information System (INIS)

    Swordy, Simon

    2007-01-01

    I will discuss some recent experiments using slow light and entangled photons. We recently showed that it was possible to map a two dimensional image onto very low light level signals, slow them down in a hot atomic vapor while preserving the amplitude and phase of the images. If time remains, I will discuss some of our recent work with time-energy entangled photons for quantum cryptography. We were able to show that we could have a measurable state space of over 1000 states for a single pair of entangled photons in fiber.

  19. Pulsar slow-down epochs

    International Nuclear Information System (INIS)

    Heintzmann, H.; Novello, M.

    1981-01-01

    The relative importance of magnetospheric currents and low frequency waves for pulsar braking is assessed and a model is developed which tries to account for the available pulsar timing data under the unifying aspect that all pulsars have equal masses and magnetic moments and are born as rapid rotators. Four epochs of slow-down are distinguished which are dominated by different braking mechanisms. According to the model no direct relationship exists between 'slow-down age' and true age of a pulsar and leads to a pulsar birth-rate of one event per hundred years. (Author) [pt

  20. Interaction of slow pions with atomic nuclei

    International Nuclear Information System (INIS)

    Troitskij, M.A.; Tsybul'nikov, A.V.; Chekunaev, N.I.

    1984-01-01

    Interactions of slow pions with atomic nuclei near to pion condensation are investigated. From comparison of experimental data with the theoretical calculation results on the basis of precise microscopic approach not bound with the random phase approximation (RPA) nuclear matter fundamental parameters near a critical point can be found. Optical potential of slow pions in nuclei, πN-scattering amplitudes and lengths, π-atom level isotopic shift, phenomenon of single-nucleon pion absorption by nucleus, phenomenon of nuclear critical opalescence are considered. The results of πN-scattering lengths calculation, sup(40-44)Ca, sup(24-29)Mg, sup(16-18)O π-atom level shift are presented. It is shown that the presence of π-condensate in nuclei can explain the observed suppression of p-wave potential terms. The phenomenon of single-nucleon pion absorption by nucleus is one of direct experiments which permits to reveal the π-condensate. The nuclear opalescence phenomenon is manifested in increase of pion photoproduction reaction cross section for account of nucleus proximity to π-condensation as compared with the calculated in the Fermi-gas model. The suggested method for calculating precondensate phenomena operates the better, the nearer is the system to the condensation threshold whereas the RPA method in this region is inapplicable

  1. Nifedipine-loaded polymeric nanocapsules: validation of a stability-indicating HPLC method to evaluate the drug entrapment efficiency and in vitro release profiles.

    Science.gov (United States)

    Granada, Andréa; Tagliari, Monika Piazzon; Soldi, Valdir; Silva, Marcos António Segatto; Zanetti-Ramos, Betina Ghiel; Fernandes, Daniel; Stulzer, Hellen Karine

    2013-01-01

    A simple stability-indicating analytical method was developed and validated to quantify nifedipine in polymeric nanocapsule suspensions; an in vitro drug release study was then carried out. The analysis was performed using an RP C18 column, UV-Vis detection at 262 nm, and methanol-water (70 + 30, v/v) mobile phase at a flow rate of 1.2 mL/min. The method was validated in terms of specificity, linearity and range, LOQ, accuracy, precision, and robustness. The results obtained were within the acceptable ranges. The nanocapsules, made of poly(epsilon-caprolactone), were prepared by the solvent displacement technique and showed high entrapment efficiency. The entrapment efficiency was 97.6 and 98.2% for the nifedipine-loaded polymeric nanocapsules prepared from polyvinyl alcohol (PVA) and Pluronic F68 (PF68), respectively. The particle size and zeta potential of nanocapsules were found to be influenced by the nature of the stabilizer used. The mean diameter and zeta potential for nanocapsules with PVA and PF68 were 290.9 and 179.9 nm, and -17.7 mV and -32.7 mV, respectively. The two formulations prepared showed a drug release of up to 70% over 4 days. This behavior indicates the viability of this drug delivery system for use as a controlled-release system.

  2. A slowing-down problem

    Energy Technology Data Exchange (ETDEWEB)

    Carlvik, I; Pershagen, B

    1958-06-15

    An infinitely long circular cylinder of radius a is surrounded by an infinite moderator. Both media are non-capturing. The cylinder emits neutrons of age zero with a constant source density of S. We assume that the ratios of the slowing-down powers and of the diffusion constants are independent of the neutron energy. The slowing-down density is calculated for two cases, a) when the slowing-down power of the cylinder medium is very small, and b) when the cylinder medium is identical with the moderator. The ratios of the slowing-down density at the age {tau} and the source density in the two cases are called {psi}{sub V}, and {psi}{sub M} respectively. {psi}{sub V} and {psi}{sub M} are functions of y=a{sup 2}/4{tau}. These two functions ({psi}{sub V} and {psi}{sub M}) are calculated and tabulated for y = 0-0.25.

  3. Numerical modeling of slow shocks

    International Nuclear Information System (INIS)

    Winske, D.

    1987-01-01

    This paper reviews previous attempt and the present status of efforts to understand the structure of slow shocks by means of time dependent numerical calculations. Studies carried out using MHD or hybrid-kinetic codes have demonstrated qualitative agreement with theory. A number of unresolved issues related to hybrid simulations of the internal shock structure are discussed in some detail. 43 refs., 8 figs

  4. The unappreciated slowness of conventional tourism

    Directory of Open Access Journals (Sweden)

    G.R. Larsen

    2016-05-01

    Full Text Available Most tourists are not consciously engaging in ‘slow travel’, but a number of travel behaviours displayed by conventional tourists can be interpreted as slow travel behaviour. Based on Danish tourists’ engagement with the distances they travel across to reach their holiday destination, this paper explores unintended slow travel behaviours displayed by these tourists. None of the tourists participating in this research were consciously doing ‘slow travel’, and yet some of their most valued holiday memories are linked to slow travel behaviours. Based on the analysis of these unintended slow travel behaviours, this paper will discuss the potential this insight might hold for promotion of slow travel. If unappreciated and unintentional slow travel behaviours could be utilised in the deliberate effort of encouraging more people to travel slow, ‘slow travel’ will be in a better position to become integrated into conventional travel behaviour.

  5. EFFECT OF ISRADIPINE AND NIFEDIPINE ON DIASTOLIC FUNCTION IN PATIENTS WITH LEFT-VENTRICULAR DYSFUNCTION DUE TO CORONARY-ARTERY DISEASE - A RANDOMIZED, DOUBLE-BLIND, NUCLEAR, STETHOSCOPE STUDY

    NARCIS (Netherlands)

    VANDENTOREN, EW; DEVRIES, RJM; PORTEGIES, MCM; BLANKSMA, PK; VANGILST, WH; HILLEGE, HJ; VANVELDHUISEN, DJ; LIE, KI

    To elucidate the effect of isradipine and nifedipine on left ventricular (LV) systolic and diastolic function, each drug was given intravenously (i.v.) in equihypotensive doses to 10 patients accepted for coronary arteriography for stable angina pectoris. All 20 patients had LV ejection fraction

  6. A Primer to Slow Light

    OpenAIRE

    Leonhardt, U.

    2001-01-01

    Laboratory-based optical analogs of astronomical objects such as black holes rely on the creation of light with an extremely low or even vanishing group velocity (slow light). These brief notes represent a pedagogical attempt towards elucidating this extraordinary form of light. This paper is a contribution to the book Artificial Black Holes edited by Mario Novello, Matt Visser and Grigori Volovik. The paper is intended as a primer, an introduction to the subject for non-experts, not as a det...

  7. Capillary waves in slow motion

    International Nuclear Information System (INIS)

    Seydel, Tilo; Tolan, Metin; Press, Werner; Madsen, Anders; Gruebel, Gerhard

    2001-01-01

    Capillary wave dynamics on glycerol surfaces has been investigated by means of x-ray photon correlation spectroscopy performed at grazing angles. The measurements show that thermally activated capillary wave motion is slowed down exponentially when the sample is cooled below 273 K. This finding directly reflects the freezing of the surface waves. The wave-number dependence of the measured time constants is in quantitative agreement with theoretical predictions for overdamped capillary waves

  8. The fast slow TDPAC spectrometer

    International Nuclear Information System (INIS)

    Cekic, B.; Koicki, S.; Manasijevic, M.; Ivanovic, N.; Koteski, V.; Milosevic, Z.; Radisavljevic, I.; Cavor, J.; Novakovic, N.; Marjanovic, D.

    2001-01-01

    A 2-BaF 2 detector - fast slow time spectrometer for time differential perturbed angular correlations (TDPAC) experiments is described. This apparatus has been developed in the Group for Hyperfine Interactions in the Institute for Nuclear Sciences in VINCA. The excellent time resolution combined with high efficiency offered by these detectors enables one high counting rate performance and is operating in the wide temperature range 78-1200 K. (author)

  9. Hidden slow pulsars in binaries

    Science.gov (United States)

    Tavani, Marco; Brookshaw, Leigh

    1993-01-01

    The recent discovery of the binary containing the slow pulsar PSR 1718-19 orbiting around a low-mass companion star adds new light on the characteristics of binary pulsars. The properties of the radio eclipses of PSR 1718-19 are the most striking observational characteristics of this system. The surface of the companion star produces a mass outflow which leaves only a small 'window' in orbital phase for the detection of PSR 1718-19 around 400 MHz. At this observing frequency, PSR 1718-19 is clearly observable only for about 1 hr out of the total 6.2 hr orbital period. The aim of this Letter is twofold: (1) to model the hydrodynamical behavior of the eclipsing material from the companion star of PSR 1718-19 and (2) to argue that a population of binary slow pulsars might have escaped detection in pulsar surveys carried out at 400 MHz. The possible existence of a population of partially or totally hidden slow pulsars in binaries will have a strong impact on current theories of binary evolution of neutron stars.

  10. Adaptation in the visual cortex: influence of membrane trajectory and neuronal firing pattern on slow afterpotentials.

    Directory of Open Access Journals (Sweden)

    Vanessa F Descalzo

    Full Text Available The input/output relationship in primary visual cortex neurons is influenced by the history of the preceding activity. To understand the impact that membrane potential trajectory and firing pattern has on the activation of slow conductances in cortical neurons we compared the afterpotentials that followed responses to different stimuli evoking similar numbers of action potentials. In particular, we compared afterpotentials following the intracellular injection of either square or sinusoidal currents lasting 20 seconds. Both stimuli were intracellular surrogates of different neuronal responses to prolonged visual stimulation. Recordings from 99 neurons in slices of visual cortex revealed that for stimuli evoking an equivalent number of spikes, sinusoidal current injection activated a slow afterhyperpolarization of significantly larger amplitude (8.5 ± 3.3 mV and duration (33 ± 17 s than that evoked by a square pulse (6.4 ± 3.7 mV, 28 ± 17 s; p<0.05. Spike frequency adaptation had a faster time course and was larger during plateau (square pulse than during intermittent (sinusoidal depolarizations. Similar results were obtained in 17 neurons intracellularly recorded from the visual cortex in vivo. The differences in the afterpotentials evoked with both protocols were abolished by removing calcium from the extracellular medium or by application of the L-type calcium channel blocker nifedipine, suggesting that the activation of a calcium-dependent current is at the base of this afterpotential difference. These findings suggest that not only the spikes, but the membrane potential values and firing patterns evoked by a particular stimulation protocol determine the responses to any subsequent incoming input in a time window that spans for tens of seconds to even minutes.

  11. Slow electrons kill the ozone

    International Nuclear Information System (INIS)

    Maerk, T.

    2001-01-01

    A new method and apparatus (Trochoidal electron monochromator) to study the interactions of electrons with atoms, molecules and clusters was developed. Two applications are briefly reported: a) the ozone destruction in the atmosphere is caused by different reasons, a new mechanism is proposed, that slow thermal electrons are self added to the ozone molecule (O 3 ) with a high frequency, then O 3 is destroyed ( O 3 + e - → O - + O 2 ); b) another application is the study of the binding energy of the football molecule C60. (nevyjel)

  12. The CUORE slow monitoring systems

    Science.gov (United States)

    Gladstone, L.; Biare, D.; Cappelli, L.; Cushman, J. S.; Del Corso, F.; Fujikawa, B. K.; Hickerson, K. P.; Moggi, N.; Pagliarone, C. E.; Schmidt, B.; Wagaarachchi, S. L.; Welliver, B.; Winslow, L. A.

    2017-09-01

    CUORE is a cryogenic experiment searching primarily for neutrinoless double decay in 130Te. It will begin data-taking operations in 2016. To monitor the cryostat and detector during commissioning and data taking, we have designed and developed Slow Monitoring systems. In addition to real-time systems using LabVIEW, we have an alarm, analysis, and archiving website that uses MongoDB, AngularJS, and Bootstrap software. These modern, state of the art software packages make the monitoring system transparent, easily maintainable, and accessible on many platforms including mobile devices.

  13. Blowup for flat slow manifolds

    DEFF Research Database (Denmark)

    Kristiansen, Kristian Uldall

    2017-01-01

    In this paper, we present a way of extending the blowup method, in the formulation of Krupa and Szmolyan, to flat slow manifolds that lose hyperbolicity beyond any algebraic order. Although these manifolds have infinite co-dimensions, they do appear naturally in certain settings; for example, in (a......) the regularization of piecewise smooth systems by tanh, (b) a particular aircraft landing dynamics model, and finally (c) in a model of earthquake faulting. We demonstrate the approach using a simple model system and the examples (a) and (b)....

  14. Blowup for flat slow manifolds

    Science.gov (United States)

    Kristiansen, K. U.

    2017-05-01

    In this paper, we present a way of extending the blowup method, in the formulation of Krupa and Szmolyan, to flat slow manifolds that lose hyperbolicity beyond any algebraic order. Although these manifolds have infinite co-dimensions, they do appear naturally in certain settings; for example, in (a) the regularization of piecewise smooth systems by \\tanh , (b) a particular aircraft landing dynamics model, and finally (c) in a model of earthquake faulting. We demonstrate the approach using a simple model system and the examples (a) and (b).

  15. Connecting slow earthquakes to huge earthquakes

    OpenAIRE

    Obara, Kazushige; Kato, Aitaro

    2016-01-01

    Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of th...

  16. Integrated Photonics Enabled by Slow Light

    DEFF Research Database (Denmark)

    Mørk, Jesper; Chen, Yuntian; Ek, Sara

    2012-01-01

    In this talk we will discuss the physics of slow light in semiconductor materials and in particular the possibilities offered for integrated photonics. This includes ultra-compact slow light enabled optical amplifiers, lasers and pulse sources.......In this talk we will discuss the physics of slow light in semiconductor materials and in particular the possibilities offered for integrated photonics. This includes ultra-compact slow light enabled optical amplifiers, lasers and pulse sources....

  17. Slowing down bubbles with sound

    Science.gov (United States)

    Poulain, Cedric; Dangla, Remie; Guinard, Marion

    2009-11-01

    We present experimental evidence that a bubble moving in a fluid in which a well-chosen acoustic noise is superimposed can be significantly slowed down even for moderate acoustic pressure. Through mean velocity measurements, we show that a condition for this effect to occur is for the acoustic noise spectrum to match or overlap the bubble's fundamental resonant mode. We render the bubble's oscillations and translational movements using high speed video. We show that radial oscillations (Rayleigh-Plesset type) have no effect on the mean velocity, while above a critical pressure, a parametric type instability (Faraday waves) is triggered and gives rise to nonlinear surface oscillations. We evidence that these surface waves are subharmonic and responsible for the bubble's drag increase. When the acoustic intensity is increased, Faraday modes interact and the strongly nonlinear oscillations behave randomly, leading to a random behavior of the bubble's trajectory and consequently to a higher slow down. Our observations may suggest new strategies for bubbly flow control, or two-phase microfluidic devices. It might also be applicable to other elastic objects, such as globules, cells or vesicles, for medical applications such as elasticity-based sorting.

  18. A fast-slow logic system

    International Nuclear Information System (INIS)

    Kawashima, Hideo.

    1977-01-01

    A fast-slow logic system has been made for use in multi-detector experiments in nuclear physics such as particle-gamma and particle-particle coincidence experiments. The system consists of a fast logic system and a slow logic system. The fast logic system has a function of fast coincidences and provides timing signals for the slow logic system. The slow logic system has a function of slow coincidences and a routing control of input analog signals to the ADCs. (auth.)

  19. Traditional Procurement is too Slow

    Directory of Open Access Journals (Sweden)

    Ann Kong

    2012-11-01

    Full Text Available This paper reports on an exploratory interview survey of construction project participants aimed at identifying the reasons for the decrease in use of the traditional, lump-sum, procurement system in Malaysia. The results show that most people believe it is too slow. This appears to be in part due to the contiguous nature of the various phase and stages of the process and especially the separation of the design and construction phases. The delays caused by disputes between the various parties are also seen as a contributory factor - the most prominent cause being the frequency of variations, with design and scope changes being a particular source of discontent. It is concluded that an up scaling of the whole of the time related reward/penalty system may be the most appropriate measure for the practice in future.

  20. Slow pyrolysis of pistachio shell

    Energy Technology Data Exchange (ETDEWEB)

    Apaydin-Varol, Esin; Putun, Ersan; Putun, Ayse E [Anadolu University, Eskisehir (Turkey). Department of Chemical Engineering

    2007-08-15

    In this study, pistachio shell is taken as the biomass sample to investigate the effects of pyrolysis temperature on the product yields and composition when slow pyrolysis is applied in a fixed-bed reactor at atmospheric pressure to the temperatures of 300, 400, 500, 550, 700{sup o}C. The maximum liquid yield was attained at about 500-550{sup o}C with a yield of 20.5%. The liquid product obtained under this optimum temperature and solid products obtained at all temperatures were characterized. As well as proximate and elemental analysis for the products were the basic steps for characterization, column chromatography, FT-IR, GC/MS and SEM were used for further characterization. The results showed that liquid and solid products from pistachio shells show similarities with high value conventional fuels. 31 refs., 9 figs., 1 tab.

  1. The TTI slowness surface approximation

    KAUST Repository

    Stovas, A.

    2011-01-01

    The relation between the vertical and horizontal slownesses, better known as the dispersion relation, for a transversely isotropic media with titled symmetry axis {left parenthesis, less than bracket}TTI{right parenthesis, greater than bracket} requires solving a quartic polynomial, which does not admit a practical explicit solution to be used, for example, in downward continuation. Using a combination of perturbation theory with respect to the anelliptic parameter and Shanks transform to improve the accuracy of the expansion, we develop an explicit formula for the dispersion relation that is highly accurate for all practical purposes. It also reveals some insights into the anisotropy parameter dependency of the dispersion relation including the low impact that the anelliptic parameter has on the vertical placement of reflectors for small tilt in the symmetry angle. © 2011 Society of Exploration Geophysicists.

  2. Thermically stimulated exoelectronic emissions and thermoluminescence of MgO

    International Nuclear Information System (INIS)

    Chubaci, J.F.D.

    1987-01-01

    In this work, studies were performed on the following topics: i) thermically stimulated exoelectronic emission (TSEE) in pure MgO single crystals ion implanted, submitted to thermal treatment with fast on slow cooling and water adsorption; ii) ultraviolet light effect on TSEE; iii) thermoluminescent emission; iv) crystallization of FeCoB amorphous alloys. (A.C.A.S.) [pt

  3. Plant domestication slows pest evolution.

    Science.gov (United States)

    Turcotte, Martin M; Lochab, Amaneet K; Turley, Nash E; Johnson, Marc T J

    2015-09-01

    Agricultural practices such as breeding resistant varieties and pesticide use can cause rapid evolution of pest species, but it remains unknown how plant domestication itself impacts pest contemporary evolution. Using experimental evolution on a comparative phylogenetic scale, we compared the evolutionary dynamics of a globally important economic pest - the green peach aphid (Myzus persicae) - growing on 34 plant taxa, represented by 17 crop species and their wild relatives. Domestication slowed aphid evolution by 13.5%, maintained 10.4% greater aphid genotypic diversity and 5.6% higher genotypic richness. The direction of evolution (i.e. which genotypes increased in frequency) differed among independent domestication events but was correlated with specific plant traits. Individual-based simulation models suggested that domestication affects aphid evolution directly by reducing the strength of selection and indirectly by increasing aphid density and thus weakening genetic drift. Our results suggest that phenotypic changes during domestication can alter pest evolutionary dynamics. © 2015 John Wiley & Sons Ltd/CNRS.

  4. Applications of Slow Light in Telecommunications

    National Research Council Canada - National Science Library

    Boyd, Robert W; Gauthier, Daniel J; Gaeta, Alexander L

    2006-01-01

    .... Now, optical scientists are turning their attention toward developing useful applications of slow light, including controllable optical delay lines, optical buffers and true time delay methods...

  5. Mechanism of magnetoresistance ratio enhancement in MgO/NiFe/MgO heterostructure by rapid thermal annealing

    Science.gov (United States)

    Zhao, Chong-Jun; Liu, Yang; Zhang, Jing-Yan; Sun, Li; Ding, Lei; Zhang, Peng; Wang, Bao-Yi; Cao, Xing-Zhong; Yu, Guang-Hua

    2012-08-01

    To reveal thermal effects on the film quality/microstructure evolution and the resulted magnetoresistance (MR) ratio in MgO/NiFe/MgO heterostructures, positron annihilation spectroscopy studies have been performed. It is found that the ionic interstitials in the MgO layers recombine with the nearby vacancies at lower annealing temperatures (200-300 °C) and lead to a slow increase in sample MR. Meanwhile, vacancy defects agglomeration/removal and ordering acceleration in MgO will occur at higher annealing temperatures (450-550 °C) and the improved MgO and MgO/NiFe interfaces microstructure are responsible for the observed significant MR enhancement.

  6. Influência da nifedipina no bloqueio neuromuscular produzido pelo atracúrio e pelo cisatracúrio: estudo em preparações nervo frênico-diafragma de rato Influencia de la nifedipina en el bloqueo neuromuscular producido por atracurio y cisatracurio: estudio en preparación nervio frénico diafragma de ratón Influence of nifedipine on the neuromuscular block produced by atracurium and cistracurium: study in rat phrenic-diaphragmatic nerve preparation

    Directory of Open Access Journals (Sweden)

    Silmara Rodrigues de Sousa

    2006-04-01

    neuromuscular del atracurio y del cisatracurio, no cambió el potencial de membrana y produjo el aumento inicial en la frecuencia de los PPTM, seguida de bloqueo. CONCLUSIONES: La nifedipina, en la concentración empleada, potenció el bloqueo neuromuscular que el atracurio e cisatracurio produjeron. Estudios electrofisiológicos demostraron una acción presináptica y la ausencia de acción despolarizante sobre la fibra muscular.BACKGROUND AND OBJECTIVES: Calcium channel blockers may interact with neuromuscular blockers, increasing its effects. Research studies about this interaction display controversial results. In some studies these drugs produced neuromuscular blockage, or contracture, or no effect at all was proved over skeletal neuromuscular response. This study assessed the nifedipine effects over muscular responses and its possible interaction with neuromuscular blockers in rat diaphragm. METHODS: A number of 25 rats were used, weighing between 250 and 300 g and sacrificed under anesthesia with intraperitoneal pentobarbital (40 mg.kg-1. Preparation was mounted according to the technique described by Bulbring. Diaphragm was kept under tension, connected to an isometric transducer and subjected to an indirect stimulation of 0.1 Hz frequency. Diaphragm contractions were registered on a physiograph. In order to evaluate the effect of these drugs on neuromuscular transmission, they were added separately or associated to the preparation, on the following concentrations: nifedipine (4 µg.mL-1; atracurium (20 µg.mL-1; cistracurium (3 µg.mL-1. On phrenic-nerve preparation, the assessed items were: 1 the extent of diaphragm muscle response to indirect stimulation, before and 45 minutes after adding nifedipine and neuromuscular blockers separately and after the association of both drugs; 2 nifedipine effects on membrane potentials (MP and miniature end-plate potentials (MEPP. RESULTS: Employed separately, nifedipine did not alter the extent of muscular responses, but it did

  7. Nifedipine Asma y Nifedipina: estudio comparativo del efecto profiláctivo de la Nifedipina frente al Ketotifeno y placebo en Asma Alérgica Infantil

    Directory of Open Access Journals (Sweden)

    Fernando Montoya

    1988-02-01

    Full Text Available

    Between July 1984 and December 1986 a double blind randomized study was conducted at the Allergy Clinic of the Hospital Universitario San Vicente de Paúl, Medellín, Colombia, in order to compare the effects of Nifedipine, Ketotifen and placebo on allergic asthma in children; each drug and the placebo were administered orally every 12 hours for a period of 4 months to a group of 20 children. The objective was to evaluate the usefulness of Nifedipine In the prophylactic management of allergic asthma in this population and to compare it with Ketotifen, a provenly efficacious drug, and placebo.

     

    AII patients were older than 5 years and had suffered the disease for more than 2 years. Nifedipine treated patients showed a reduction In the frequency of their asthmatic crisis (17 patients; 85% and in their intensity and duration (16 patients; 80%; a similar reduction was observed In the need for bronchodilators; 18 patients {90% reported beneficial effects with this drug and medical evaluation confirmed Improvement In 14 {70%.

     

    These results resembled those obtained with Ketotifen and both were statistically superior to placebo {p<0.05. Pulmonary function tests, pulse rate and blood pressure did not show any significant changes. Secondary effects were minimal and self-Limited.

     

    It is concluded that Nifedipine can be an alternative drug for the treatment of mild to moderate allergic asthma In children. If calcium antagonists with higher

  8. Analytical method development of nifedipine and its degradants binary mixture using high performance liquid chromatography through a quality by design approach

    Science.gov (United States)

    Choiri, S.; Ainurofiq, A.; Ratri, R.; Zulmi, M. U.

    2018-03-01

    Nifedipin (NIF) is a photo-labile drug that easily degrades when it exposures a sunlight. This research aimed to develop of an analytical method using a high-performance liquid chromatography and implemented a quality by design approach to obtain effective, efficient, and validated analytical methods of NIF and its degradants. A 22 full factorial design approach with a curvature as a center point was applied to optimize of the analytical condition of NIF and its degradants. Mobile phase composition (MPC) and flow rate (FR) as factors determined on the system suitability parameters. The selected condition was validated by cross-validation using a leave one out technique. Alteration of MPC affected on time retention significantly. Furthermore, an increase of FR reduced the tailing factor. In addition, the interaction of both factors affected on an increase of the theoretical plates and resolution of NIF and its degradants. The selected analytical condition of NIF and its degradants has been validated at range 1 – 16 µg/mL that had good linearity, precision, accuration and efficient due to an analysis time within 10 min.

  9. Response of electret dosemeter to slow neutrons

    International Nuclear Information System (INIS)

    Ghilardi, A.J.P.; Pela, C.A.; Zimmerman, R.L.

    1987-01-01

    The response of electret dosemeter to slow neutrons exposure is cited, mentioning the preparation and the irradiation of dosemeter with Am-Be source. Some theory considerations about the response of electret dosemeter to slow and fast neutrons are also presented. (C.G.C.) [pt

  10. Tandem queue with server slow-down

    NARCIS (Netherlands)

    Miretskiy, D.I.; Scheinhardt, W.R.W.; Mandjes, M.R.H.

    2007-01-01

    We study how rare events happen in the standard two-node tandem Jackson queue and in a generalization, the socalled slow-down network, see [2]. In the latter model the service rate of the first server depends on the number of jobs in the second queue: the first server slows down if the amount of

  11. Slow-light pulses in moving media

    International Nuclear Information System (INIS)

    Fiurasek, J.; Leonhardt, U.; Parentani, R.

    2002-01-01

    Slow light in moving media reaches a counterintuitive regime when the flow speed of the medium approaches the group velocity of light. Pulses can penetrate a region where a counterpropagating flow exceeds the group velocity. When the counterflow slows down, pulses are reflected

  12. Can fast and slow intelligence be differentiated?

    NARCIS (Netherlands)

    Partchev, I.; de Boeck, P.

    2012-01-01

    Responses to items from an intelligence test may be fast or slow. The research issue dealt with in this paper is whether the intelligence involved in fast correct responses differs in nature from the intelligence involved in slow correct responses. There are two questions related to this issue: 1.

  13. Slow Movement/Slow University: Critical Engagements. Introduction to the Thematic Section

    Directory of Open Access Journals (Sweden)

    Maggie O'Neill

    2014-09-01

    Full Text Available This thematic section emerged from two seminars that took place at Durham University in England in November 2013 and March 2014 on the possibilities for thinking through what a change movement towards slow might mean for the University. Slow movements have emerged in relation to a number of topics: Slow food, Citta slow and more recently, slow science. What motivated us in the seminars was to explore how far these movements could help us address the acceleration and intensification of work within our own and other universities, and indeed, what new learning, research, philosophies, practices, structures and governance might emerge. This editorial introduction presents the concept of the "slow university" and introduces our critical engagements with slow. The articles presented here interrogate the potentialities, challenges, problems and pitfalls of the slow university in an era of corporate culture and management rationality. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1403166

  14. Connecting slow earthquakes to huge earthquakes.

    Science.gov (United States)

    Obara, Kazushige; Kato, Aitaro

    2016-07-15

    Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of their high sensitivity to stress changes in the seismogenic zone. Episodic stress transfer to megathrust source faults leads to an increased probability of triggering huge earthquakes if the adjacent locked region is critically loaded. Careful and precise monitoring of slow earthquakes may provide new information on the likelihood of impending huge earthquakes. Copyright © 2016, American Association for the Advancement of Science.

  15. Mg-MOF-74/MgF₂ Composite Coating for Improving the Properties of Magnesium Alloy Implants: Hydrophilicity and Corrosion Resistance.

    Science.gov (United States)

    Liu, Wei; Yan, Zhijie; Ma, Xiaolu; Geng, Tie; Wu, Haihong; Li, Zhongyue

    2018-03-07

    Surface modification on Mg alloys is highly promising for their application in the field of bone repair. In this study, a new metal-organic framework/MgF₂ (Mg-MOF-74/MgF₂) composite coating was prepared on the surface of AZ31B Mg alloy via pre-treatment of hydrofluoric acid and in situ hydrothermal synthesis methods. The surface topography of the composite coating is compact and homogeneous, and Mg-MOF-74 has good crystallinity. The corrosion resistance of this composite coating was investigated through Tafel polarization test and immersion test in simulated body fluid at 37 °C. It was found that Mg-MOF-74/MgF₂ composite coating significantly slowed down the corrosion rate of Mg alloy. Additionally, Mg-MOF-74/MgF₂ composite coating expresses super-hydrophilicity with the water contact angle of nearly 0°. In conclusion, on the basis of MgF₂ anticorrosive coating, the introduction of Mg-MOF-74 further improves the biological property of Mg alloys. At last, we propose that the hydrophilicity of the composite coating is mainly owing to the large number of hydroxyl groups, the high specific surface area of Mg-MOF-74, and the rough coating produced by Mg-MOF-74 particles. Hence, Mg-MOF-74 has a great advantage in enhancing the hydrophilicity of Mg alloy surface.

  16. Effect of different seawater Mg

    NARCIS (Netherlands)

    Mewes, A.; Langer, G.; de Nooijer, L.J.; Bijma, J.; Reichart, G.J.

    2014-01-01

    Magnesium, incorporated in foraminiferal calcite (Mg/CaCC), is used intensively to reconstruct past seawater temperatures but, in addition to temperature, the Mg/CaCC of foraminiferal tests also depends on the ratio of Mg and Ca in seawater (Mg/CaSW). The physiological mechanisms responsible for

  17. KEK-IMSS Slow Positron Facility

    Energy Technology Data Exchange (ETDEWEB)

    Hyodo, T; Wada, K; Yagishita, A; Kosuge, T; Saito, Y; Kurihara, T; Kikuchi, T; Shirakawa, A; Sanami, T; Ikeda, M; Ohsawa, S; Kakihara, K; Shidara, T, E-mail: toshio.hyodo@kek.jp [High Energy Accelerator Research Organization (KEK) 1-1 Oho, Tsukuba, Ibaraki, 305-0801 (Japan)

    2011-12-01

    The Slow Positron Facility at the Institute of Material Structure Science (IMSS) of High Energy Accelerator Research Organization (KEK) is a user dedicated facility with an energy tunable (0.1 - 35 keV) slow positron beam produced by a dedicated 55MeV linac. The present beam line branches have been used for the positronium time-of-flight (Ps-TOF) measurements, the transmission positron microscope (TPM) and the photo-detachment of Ps negative ions (Ps{sup -}). During the year 2010, a reflection high-energy positron diffraction (RHEPD) measurement station is going to be installed. The slow positron generator (converter/ moderator) system will be modified to get a higher slow positron intensity, and a new user-friendly beam line power-supply control and vacuum monitoring system is being developed. Another plan for this year is the transfer of a {sup 22}Na-based slow positron beam from RIKEN. This machine will be used for the continuous slow positron beam applications and for the orientation training of those who are interested in beginning researches with a slow positron beam.

  18. The cryogenic source of slow monochromatic positrons

    International Nuclear Information System (INIS)

    Meshkov, I.N.; Pavlov, V.N.; Sidorin, A.O.; Yakovenko, S.L.

    2008-01-01

    The cryogenic source of slow monochromatic positrons based on the 22 Na isotope has been designed and constructed at JINR. Positrons emitted from radioactive source 22 Na have a very broad energy spectrum up to 0.5 MeV. To generate monochromatic beam of slow positrons the solid neon is used as a moderator. The solid neon allows forming slow positron beam of the energy of 1.2 eV at the spectrum width of 1 eV. The efficiency of moderation is 1 % of total positron flux

  19. Dystonia Associated with Idiopathic Slow Orthostatic Tremor

    Directory of Open Access Journals (Sweden)

    Christopher Kobylecki

    2016-02-01

    Full Text Available Background: We aimed to characterize the clinical and electrophysiological features of patients with slow orthostatic tremor.Case Report: The clinical and neurophysiological data of patients referred for lower limb tremor on standing were reviewed. Patients with symptomatic or primary orthostatic tremor were excluded. Eight patients were identified with idiopathic slow 4–8 Hz orthostatic tremor, which was associated with tremor and dystonia in cervical and upper limb musculature. Coherence analysis in two patients showed findings different to those seen in primary orthostatic tremor.Discussion: Slow orthostatic tremor may be associated with dystonia and dystonic tremor.

  20. Revealing the cluster of slow transients behind a large slow slip event.

    Science.gov (United States)

    Frank, William B; Rousset, Baptiste; Lasserre, Cécile; Campillo, Michel

    2018-05-01

    Capable of reaching similar magnitudes to large megathrust earthquakes [ M w (moment magnitude) > 7], slow slip events play a major role in accommodating tectonic motion on plate boundaries through predominantly aseismic rupture. We demonstrate here that large slow slip events are a cluster of short-duration slow transients. Using a dense catalog of low-frequency earthquakes as a guide, we investigate the M w 7.5 slow slip event that occurred in 2006 along the subduction interface 40 km beneath Guerrero, Mexico. We show that while the long-period surface displacement, as recorded by Global Positioning System, suggests a 6-month duration, the motion in the direction of tectonic release only sporadically occurs over 55 days, and its surface signature is attenuated by rapid relocking of the plate interface. Our proposed description of slow slip as a cluster of slow transients forces us to re-evaluate our understanding of the physics and scaling of slow earthquakes.

  1. Ursodeoxycholic acid prevents ventricular conduction slowing and arrhythmia by restoring T-type calcium current in fetuses during cholestasis

    Science.gov (United States)

    Adeyemi, Oladipupo; Alvarez-Laviada, Anita; Schultz, Francisca; Ibrahim, Effendi; Trauner, Michael; Williamson, Catherine; Glukhov, Alexey V.

    2017-01-01

    Background Increased maternal serum bile acid concentrations in intrahepatic cholestasis of pregnancy (ICP) are associated with fetal cardiac arrhythmias. Ursodeoxycholic acid (UDCA) has been shown to demonstrate anti-arrhythmic properties via preventing ICP-associated cardiac conduction slowing and development of reentrant arrhythmias, although the cellular mechanism is still being elucidated. Methods High-resolution fluorescent optical mapping of electrical activity and electrocardiogram measurements were used to characterize effects of UDCA on one-day-old neonatal and adult female Langendorff-perfused rat hearts. ICP was modelled by perfusion of taurocholic acid (TC, 400μM). Whole-cell calcium currents were recorded from neonatal rat and human fetal cardiomyocytes. Results TC significantly prolonged the PR interval by 11.0±3.5% (P<0.05) and slowed ventricular conduction velocity (CV) by 38.9±5.1% (P<0.05) exclusively in neonatal and not in maternal hearts. A similar CV decline was observed with the selective T-type calcium current (ICa,T) blocker mibefradil 1μM (23.0±6.2%, P<0.05), but not with the L-type calcium current (ICa,L) blocker nifedipine 1μM (6.9±6.6%, NS). The sodium channel blocker lidocaine (30μM) reduced CV by 60.4±4.5% (P<0.05). UDCA co-treatment was protective against CV slowing induced by TC and mibefradil, but not against lidocaine. UDCA prevented the TC-induced reduction in the ICa,T density in both isolated human fetal (−10.2±1.5 versus −5.5±0.9 pA/pF, P<0.05) and neonatal rat ventricular myocytes (−22.3±1.1 versus −9.6±0.8 pA/pF, P<0.0001), whereas UDCA had limited efficacy on the ICa,L. Conclusion Our findings demonstrate that ICa,T plays a significant role in ICP-associated fetal cardiac conduction slowing and arrhythmogenesis, and is an important component of the fetus-specific anti-arrhythmic activity of UDCA. PMID:28934223

  2. Ursodeoxycholic acid prevents ventricular conduction slowing and arrhythmia by restoring T-type calcium current in fetuses during cholestasis.

    Directory of Open Access Journals (Sweden)

    Oladipupo Adeyemi

    Full Text Available Increased maternal serum bile acid concentrations in intrahepatic cholestasis of pregnancy (ICP are associated with fetal cardiac arrhythmias. Ursodeoxycholic acid (UDCA has been shown to demonstrate anti-arrhythmic properties via preventing ICP-associated cardiac conduction slowing and development of reentrant arrhythmias, although the cellular mechanism is still being elucidated.High-resolution fluorescent optical mapping of electrical activity and electrocardiogram measurements were used to characterize effects of UDCA on one-day-old neonatal and adult female Langendorff-perfused rat hearts. ICP was modelled by perfusion of taurocholic acid (TC, 400μM. Whole-cell calcium currents were recorded from neonatal rat and human fetal cardiomyocytes.TC significantly prolonged the PR interval by 11.0±3.5% (P<0.05 and slowed ventricular conduction velocity (CV by 38.9±5.1% (P<0.05 exclusively in neonatal and not in maternal hearts. A similar CV decline was observed with the selective T-type calcium current (ICa,T blocker mibefradil 1μM (23.0±6.2%, P<0.05, but not with the L-type calcium current (ICa,L blocker nifedipine 1μM (6.9±6.6%, NS. The sodium channel blocker lidocaine (30μM reduced CV by 60.4±4.5% (P<0.05. UDCA co-treatment was protective against CV slowing induced by TC and mibefradil, but not against lidocaine. UDCA prevented the TC-induced reduction in the ICa,T density in both isolated human fetal (-10.2±1.5 versus -5.5±0.9 pA/pF, P<0.05 and neonatal rat ventricular myocytes (-22.3±1.1 versus -9.6±0.8 pA/pF, P<0.0001, whereas UDCA had limited efficacy on the ICa,L.Our findings demonstrate that ICa,T plays a significant role in ICP-associated fetal cardiac conduction slowing and arrhythmogenesis, and is an important component of the fetus-specific anti-arrhythmic activity of UDCA.

  3. VERY SLOW SPEED AXIAL MOTION RELUCTANCE MOTOR

    African Journals Online (AJOL)

    Dr Obe

    1984-09-01

    Sep 1, 1984 ... VERY SLOW SPEED AXIAL MOTION RELUCTANCE MOTOR by. L. A. Agu ... order as that of the screw-thread motor can be obtained. LIST OF .... The n stator have equal non- magnetic spacers .... induction motor. An.

  4. Slow and Fast Light, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to the NASA Small Business Innovation Research (SBIR) Program 2015 Phase I Solicitation S3.08: Slow and Fast Light, Torch Technologies in partnership...

  5. Experimental demonstration of spinor slow light

    Science.gov (United States)

    Lee, Meng-Jung; Ruseckas, Julius; Lee, Chin-Yuan; Kudriašov, Viačeslav; Chang, Kao-Fang; Cho, Hung-Wen; JuzeliÅ«nas, Gediminas; Yu, Ite A.

    2016-03-01

    Over the last decade there has been a continuing interest in slow and stored light based on the electromagnetically induced transparency (EIT) effect, because of their potential applications in quantum information manipulation. However, previous experimental works all dealt with the single-component slow light which cannot be employed as a qubit. In this work, we report the first experimental demonstration of two-component or spinor slow light (SSL) using a double tripod (DT) atom-light coupling scheme. The oscillations between the two components, similar to the Rabi oscillation of a two-level system or a qubit, were observed. Single-photon SSL can be considered as two-color qubits. We experimentally demonstrated a possible application of the DT scheme as quantum memory and quantum rotator for the two-color qubits. This work opens up a new direction in the slow light research.

  6. Elastic scattering of slow positrons by helium

    International Nuclear Information System (INIS)

    Amusia, M.Ya.; Cherepkov, N.A.; Chernysheva, L.V.; Shapiro, S.G.

    1976-01-01

    The s-, p-, d- and f-wave phaseshifts for elastic scattering of slow positrons by He are calculated using a simplified version of the random phase approximation with exchange, with virtual positronium formation effect taken into account. (author)

  7. A tilted transversely isotropic slowness surface approximation

    KAUST Repository

    Stovas, A.; Alkhalifah, Tariq Ali

    2012-01-01

    for the vertical slowness that is highly accurate for all practical purposes. It also reveals some insights into the anisotropy parameter dependency of the dispersion relation including the low impact that the anelliptic parameter has on the vertical placement

  8. Frequency response of slow beam extraction process

    International Nuclear Information System (INIS)

    Toyama, Takeshi; Sato, Hikaru; Marutsuka, Katsumi; Shirakata, Masashi.

    1994-01-01

    A servo control system has been incorporated into the practical slow extraction system in order to stabilize the spill structure less than a few kHz. Frequency responses of the components of the servo-spill control system and the open-loop frequency response were measured. The beam transfer function of the slow extraction process was derived from the measured data and approximated using a simple function. This is utilized to improve the performance of the servo-loop. (author)

  9. Slow potentials in a melody recognition task.

    Science.gov (United States)

    Verleger, R; Schellberg, D

    1990-01-01

    In a previous study, slow negative shifts were found in the EEG of subjects listening to well-known melodies. The two experiments reported here were designed to investigate the variables to which these slow potentials are related. In the first experiment, two opposite hypotheses were tested: The slow shifts might express subjects' acquaintance with the melodies or, on the contrary, the effort invested to identify them. To this end, some of the melodies were presented in the rhythms of other melodies to make recognition more difficult. Further, melodies rated as very well-known and as very unknown were analysed separately. However, the slow shifts were not affected by these experimental variations. Therefore in the second experiment, on the one hand the purely physical parameters intensity and duration were varied, but this variation had no impact on the slow shifts either. On the other hand, recognition was made more difficult by monotonously repeating the pitch of the 4th tone for the rest of some melodies. The slow negative shifts were enhanced with these monotonous melodies. This enhancement supports the "effort" hypothesis. Accordingly, the ofter shifts obtained in both experiments might likewise reflect effort. But since the task was not demanding, it is suggested that these constant shifts reflect the effort invested for coping with the entire underarousing situation rather than with the task. Frequently, slow eye movements occurred in the same time range as the slow potentials, resulting in EOG potentials spreading to the EEG recording sites. Yet results did not change substantially when the EEG recordings were corrected for the influence of EOG potentials.

  10. Development of a chromatographic method with multi-criteria decision making design for simultaneous determination of nifedipine and atenolol in content uniformity testing.

    Science.gov (United States)

    Ahmed, Sameh; Alqurshi, Abdulmalik; Mohamed, Abdel-Maaboud Ismail

    2018-07-01

    A new robust and reliable high-performance liquid chromatography (HPLC) method with multi-criteria decision making (MCDM) approach was developed to allow simultaneous quantification of atenolol (ATN) and nifedipine (NFD) in content uniformity testing. Felodipine (FLD) was used as an internal standard (I.S.) in this study. A novel marriage between a new interactive response optimizer and a HPLC method was suggested for multiple response optimizations of target responses. An interactive response optimizer was used as a decision and prediction tool for the optimal settings of target responses, according to specified criteria, based on Derringer's desirability. Four independent variables were considered in this study: Acetonitrile%, buffer pH and concentration along with column temperature. Eight responses were optimized: retention times of ATN, NFD, and FLD, resolutions between ATN/NFD and NFD/FLD, and plate numbers for ATN, NFD, and FLD. Multiple regression analysis was applied in order to scan the influences of the most significant variables for the regression models. The experimental design was set to give minimum retention times, maximum resolution and plate numbers. The interactive response optimizer allowed prediction of optimum conditions according to these criteria with a good composite desirability value of 0.98156. The developed method was validated according to the International Conference on Harmonization (ICH) guidelines with the aid of the experimental design. The developed MCDM-HPLC method showed superior robustness and resolution in short analysis time allowing successful simultaneous content uniformity testing of ATN and NFD in marketed capsules. The current work presents an interactive response optimizer as an efficient platform to optimize, predict responses, and validate HPLC methodology with tolerable design space for assay in quality control laboratories. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Host-guest complexes of 2-hydroxypropyl-β-cyclodextrin/β-cyclodextrin and nifedipine: 1H NMR, molecular modeling, and dissolution studies

    Science.gov (United States)

    de Araújo, Márcia Valéria Gaspar; Vieira, João Victor Francisco; da Silva, Caroline W. P.; Barison, Andersson; Andrade, George Ricardo Santana; da Costa, Nivan Bezerra; Barboza, Fernanda Malaquias; Nadal, Jessica Mendes; Novatski, Andressa; Farago, Paulo Vitor; Zawadzki, Sônia Faria

    2017-12-01

    Nifedipine (NIF) is a hydrophobic drug widely used for treating cardiovascular diseases. This calcium channel blocker can present a higher apparent solubility by its inclusion into different cyclodextrins (CDs) as host-guest complexes. This paper focused on the structural investigation and dissolution behavior of inclusion complexes prepared with 2-hydroxypropyl-β-cyclodextrin (HPβCD) or β-cyclodextrin (βCD) and NIF. Drug amorphization was observed for HPβCD/NIF and βCD/NIF inclusion complexes by X-ray diffractometry (XRD). The sharp endothermic peak of NIF was not observed for these both host-guest complexes by differential scanning calorimetry (DSC). These results of XRD and DSC provide evidences of complexation between drug and the investigated CDs. 1H and saturation transfer difference nuclear magnetic resonance studies revealed the enhancement in the signal at 2.27 ppm for HPβCD/NIF and βCD/NIF inclusion complexes that corresponded to the methyl groups of NIF from the non-aromatic ring. This result suggested that non-aromatic ring of NIF was inserted into HPβCD and βCD cavities. Considering the mathematical simulations, it was observed that the inclusion process can occur in the both NH-in or NH-out forms. However, since it was used aqueous medium, it is possible to indicate that the obtained host-guest complexes HPβCD/NIF and βCD/NIF are in NH-in form which corresponded to the previous results obtained by 1H NMR experiments. Dissolution assays demonstrated that NIF inclusion complexes improved the drug release nevertheless without changing its biexponential release behavior. These host-guest complexes can be further used as feasible NIF carriers in solid dosage forms.

  12. AMOC studies of positronium in fine MgO powder

    International Nuclear Information System (INIS)

    Waeyenberge, B. van; Dauwe, C.

    2001-01-01

    A first set of AMOC spectra on fine powdered MgO were measured at the Stuttgart relativistic positron beam facility. A special AMOC spectrometer was set up in order to determine the long lifetimes of ortho-positronium in the powder cavities. The spectra were taken on pellets of pressed powder in air and in an oxygen atmosphere to ensure ortho- to para-positronium conversion. An analysis of the data is made in the light of previous lifetime measurements on MgO. Here the lifetime spectrum was fitted with an age dependent lifetime describing the slow thermalisation of epithermal ortho-positronium between the powder grains. Based on the lifetime spectrum of the integrated AMOC spectra the data could not discriminate between a 5-component model and a model including slow positronium thermalisation. On the other hand, analysis of the age dependent line shape parameter shows better variances for a thermalisation model. (orig.)

  13. AMOC studies of positronium in fine MgO powder

    Energy Technology Data Exchange (ETDEWEB)

    Waeyenberge, B. van; Dauwe, C. [Ghent Univ. (Belgium). Dept. of Subatomic and Radiation Physics; Stoll, H. [Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany)

    2001-07-01

    A first set of AMOC spectra on fine powdered MgO were measured at the Stuttgart relativistic positron beam facility. A special AMOC spectrometer was set up in order to determine the long lifetimes of ortho-positronium in the powder cavities. The spectra were taken on pellets of pressed powder in air and in an oxygen atmosphere to ensure ortho- to para-positronium conversion. An analysis of the data is made in the light of previous lifetime measurements on MgO. Here the lifetime spectrum was fitted with an age dependent lifetime describing the slow thermalisation of epithermal ortho-positronium between the powder grains. Based on the lifetime spectrum of the integrated AMOC spectra the data could not discriminate between a 5-component model and a model including slow positronium thermalisation. On the other hand, analysis of the age dependent line shape parameter shows better variances for a thermalisation model. (orig.)

  14. Slow brushing reduces heat pain in humans.

    Science.gov (United States)

    Liljencrantz, J; Strigo, I; Ellingsen, D M; Krämer, H H; Lundblad, L C; Nagi, S S; Leknes, S; Olausson, H

    2017-08-01

    C-tactile (CT) afferents are unmyelinated low-threshold mechanoreceptors optimized for signalling affective, gentle touch. In three separate psychophysical experiments, we examined the contribution of CT afferents to pain modulation. In total, 44 healthy volunteers experienced heat pain and CT optimal (slow brushing) and CT sub-optimal (fast brushing or vibration) stimuli. Three different experimental paradigms were used: Concurrent application of heat pain and tactile (slow brushing or vibration) stimulation; Slow brushing, applied for variable duration and intervals, preceding heat pain; Slow versus fast brushing preceding heat pain. Slow brushing was effective in reducing pain, whereas fast brushing or vibration was not. The reduction in pain was significant not only when the CT optimal touch was applied simultaneously with the painful stimulus but also when the two stimuli were separated in time. For subsequent stimulation, the pain reduction was more pronounced for a shorter time interval between brushing and pain. Likewise, the effect was more robust when pain was preceded by a longer duration of brush stimulation. Strong CT-related pain reduction was associated with low anxiety and high calmness scores obtained by a state anxiety questionnaire. Slow brushing - optimal for CT activation - is effective in reducing pain from cutaneous heating. The precise mechanisms for the pain relief are as yet unknown but possible mechanisms include inhibition of nociceptive projection neurons at the level of the dorsal horn as well as analgesia through cortical mechanisms. Slow brushing stimuli - optimal for activation of C-tactile fibres - can reduce pain from cutaneous heating. No such effect was seen with fast brushing or vibration. These observations indicate the role of C-tactile fibres in pain modulation. © 2017 European Pain Federation - EFIC®.

  15. Quasicrystal-reinforced Mg alloys.

    Science.gov (United States)

    Kyun Kim, Young; Tae Kim, Won; Hyang Kim, Do

    2014-04-01

    The formation of the icosahedral phase (I-phase) as a secondary solidification phase in Mg-Zn-Y and Mg-Zn-Al base systems provides useful advantages in designing high performance wrought magnesium alloys. The strengthening in two-phase composites (I-phase + α -Mg) can be explained by dispersion hardening due to the presence of I-phase particles and by the strong bonding property at the I-phase/matrix interface. The presence of an additional secondary solidification phase can further enhance formability and mechanical properties. In Mg-Zn-Y alloys, the co-presence of I and Ca 2 Mg 6 Zn 3 phases by addition of Ca can significantly enhance formability, while in Mg-Zn-Al alloys, the co-presence of the I-phase and Mg 2 Sn phase leads to the enhancement of mechanical properties. Dynamic and static recrystallization are significantly accelerated by addition of Ca in Mg-Zn-Y alloy, resulting in much smaller grain size and more random texture. The high strength of Mg-Zn-Al-Sn alloys is attributed to the presence of finely distributed Mg 2 Sn and I-phase particles embedded in the α -Mg matrix.

  16. Slow electron contribution to inelastic reflection anisotropy

    International Nuclear Information System (INIS)

    Podsvirov, O.A.; Kuznetsov, Yu.A.

    1980-01-01

    Investigated is electron contribution with low energy (up to 1 keV) to the anisotropy of electron inelastic reflection (IRE) from silicon monocrystal (111) within 12-50 keV energy range of primary electrons. Experimental data on IRE anisotropy are presented: delay curves for silicon monocrystal, permitting to separate electrons with the energy up to 1 keV, dependences of IRE anisotropy on the energy of primary electrons for the systems - monocrystalline silicon-amorphous silicon film and delay curves for such systems (film thickness varies from 20 to 2000 A). Suggested is a phenomenologic model, permitting to take into account the contribution of slow electrons to IRE anisotropy: it is supposed, that three groups of electrons take part in the formation of the latter: elastic and inelastic reflected electrons, slow electrons, excited by primary electrons and slow electrons, generated by the reverse flow of the scattered electrons. Contribution of electrons, different by origin, to IRE anisotropy is evaluated in accordance with the experimental data on the basis of this model. It is stated, that slow electrons constitute approximately one half of the IRE anisotropy value, the contribution of both groups of slow electrons being approximately equal

  17. Human gamma oscillations during slow wave sleep.

    Directory of Open Access Journals (Sweden)

    Mario Valderrama

    Full Text Available Neocortical local field potentials have shown that gamma oscillations occur spontaneously during slow-wave sleep (SWS. At the macroscopic EEG level in the human brain, no evidences were reported so far. In this study, by using simultaneous scalp and intracranial EEG recordings in 20 epileptic subjects, we examined gamma oscillations in cerebral cortex during SWS. We report that gamma oscillations in low (30-50 Hz and high (60-120 Hz frequency bands recurrently emerged in all investigated regions and their amplitudes coincided with specific phases of the cortical slow wave. In most of the cases, multiple oscillatory bursts in different frequency bands from 30 to 120 Hz were correlated with positive peaks of scalp slow waves ("IN-phase" pattern, confirming previous animal findings. In addition, we report another gamma pattern that appears preferentially during the negative phase of the slow wave ("ANTI-phase" pattern. This new pattern presented dominant peaks in the high gamma range and was preferentially expressed in the temporal cortex. Finally, we found that the spatial coherence between cortical sites exhibiting gamma activities was local and fell off quickly when computed between distant sites. Overall, these results provide the first human evidences that gamma oscillations can be observed in macroscopic EEG recordings during sleep. They support the concept that these high-frequency activities might be associated with phasic increases of neural activity during slow oscillations. Such patterned activity in the sleeping brain could play a role in off-line processing of cortical networks.

  18. Magnon inflation: slow roll with steep potentials

    Energy Technology Data Exchange (ETDEWEB)

    Adshead, Peter [Department of Physics, University of Illinois at Urbana-Champaign,Urbana, IL 61801 (United States); Blas, Diego [Theoretical Physics Department, CERN,CH-1211 Geneva 23 (Switzerland); Burgess, C.P.; Hayman, Peter [Physics & Astronomy, McMaster University,Hamilton, ON, L8S 4M1 (Canada); Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Patil, Subodh P. [Department of Theoretical Physics, University of Geneva,24 Quai Ansermet, Geneva, CH-1211 (Switzerland)

    2016-11-04

    We find multi-scalar effective field theories (EFTs) that can achieve a slow inflationary roll despite having a scalar potential that does not satisfy G{sup ab}∂{sub a}V∂{sub b}V≪V{sup 2}/M{sub p}{sup 2} (where G{sub ab} is the target-space metric). They evade the usual slow-roll conditions on V because their kinetic energies are dominated by single-derivative terms rather than the usual two-derivative terms. Single derivatives dominate during slow roll and so do not require a breakdown of the usual derivative expansion that underpins calculational control in much of cosmology. The presence of such terms requires some sort of UV Lorentz-symmetry breaking during inflation (besides the usual cosmological breaking). Chromo-natural inflation provides one particular example of a UV theory that can generate the multi-field single-derivative terms we consider, and we argue that the EFT we find indeed captures the slow-roll conditions for its background evolution. We also show that our EFT can be understood as a multi-field generalization of the single-field Cuscuton models. The multi-field case introduces a new feature, however: the scalar kinetic terms define a target-space 2-form, F{sub ab}, whose antisymmetry gives new ways for slow roll to be achieved.

  19. Magnon Inflation: Slow Roll with Steep Potentials

    CERN Document Server

    Adshead, Peter; Burgess, C P; Hayman, Peter; Patil, Subodh P

    2016-01-01

    We find multi-scalar effective field theories (EFTs) that can achieve a slow inflationary roll despite having a scalar potential that does not satisfy the usual slow-roll condition (d V)^2 << V^2/Mp^2. They evade the usual slow-roll conditions on $V$ because their kinetic energies are dominated by single-derivative terms rather than the usual two-derivative terms. Single derivatives dominate during slow roll and so do not require a breakdown of the usual derivative expansion that underpins calculational control in much of cosmology. The presence of such terms requires some sort of UV Lorentz-symmetry breaking during inflation (besides the usual cosmological breaking). Chromo-natural inflation provides an example of a UV theory that can generate the multi-field single-derivative terms we consider, and we argue that the EFT we find indeed captures the slow-roll conditions for the background evolution for Chromo-natural inflation. We also show that our EFT can be understood as a multi-field generalization ...

  20. Neutron slowing-down time in matter

    Energy Technology Data Exchange (ETDEWEB)

    Chabod, Sebastien P., E-mail: sebastien.chabod@lpsc.in2p3.fr [LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut Polytechnique de Grenoble, 38000 Grenoble (France)

    2012-03-21

    We formulate the neutron slowing-down time through elastic collisions in a homogeneous, non-absorbing, infinite medium. Our approach allows taking into account for the first time the energy dependence of the scattering cross-section as well as the energy and temporal distribution of the source neutron population in the results. Starting from this development, we investigate the specific case of the propagation in matter of a mono-energetic neutron pulse. We then quantify the perturbation on the neutron slowing-down time induced by resonances in the scattering cross-section. We show that a resonance can induce a permanent reduction of the slowing-down time, preceded by two discontinuities: a first one at the resonance peak position and an echo one, appearing later. From this study, we suggest that a temperature increase of the propagating medium in presence of large resonances could modestly accelerate the neutron moderation.

  1. Kinetic slow mode-type solitons

    Directory of Open Access Journals (Sweden)

    K. Baumgärtel

    2005-01-01

    Full Text Available One-dimensional hybrid code simulations are presented, carried out in order both to study solitary waves of the slow mode branch in an isotropic, collisionless, medium-β plasma (βi=0.25 and to test the fluid based soliton interpretation of Cluster observed strong magnetic depressions (Stasiewicz et al., 2003; Stasiewicz, 2004 against kinetic theory. In the simulations, a variety of strongly oblique, large amplitude, solitons are seen, including solitons with Alfvenic polarization, similar to those predicted by the Hall-MHD theory, and robust, almost non-propagating, solitary structures of slow magnetosonic type with strong magnetic field depressions and perpendicular ion heating, which have no counterpart in fluid theory. The results support the soliton-based interpretation of the Cluster observations, but reveal substantial deficiencies of Hall-MHD theory in describing slow mode-type solitons in a plasma of moderate beta.

  2. Coagulation of highly turbid suspensions using magnesium hydroxide: effects of slow mixing conditions.

    Science.gov (United States)

    Ayoub, George M; BinAhmed, Sara W; Al-Hindi, Mahmoud; Azizi, Fouad

    2014-09-01

    Laboratory experiments were carried out to study the effects of slow mixing conditions on magnesium hydroxide floc size and strength and to determine the turbidity and total suspended solid (TSS) removal efficiencies during coagulation of highly turbid suspensions. A highly turbid kaolin clay suspension (1,213 ± 36 nephelometric turbidity units (NTU)) was alkalized to pH 10.5 using a 5 M NaOH solution; liquid bittern (LB) equivalent to 536 mg/L of Mg(2+) was added as a coagulant, and the suspension was then subjected to previously optimized fast mixing conditions of 100 rpm and 60 s. Slow mixing speed (20, 30, 40, and 50 rpm) and time (10, 20, and 30 min) were then varied, while the temperature was maintained at 20.7 ± 1 °C. The standard practice for coagulation-flocculation jar test ASTM D2035-13 (2013) was followed in all experiments. Relative floc size was monitored using an optical measuring device, photometric dispersion analyzer (PDA 2000). Larger and more shear resistant flocs were obtained at 20 rpm for both 20- and 30-min slow mixing times; however, given the shorter duration for the former, the 20-min slow mixing time was considered to be more energy efficient. For slow mixing camp number (Gt) values in the range of 8,400-90,000, it was found that the mixing speed affected floc size and strength more than the time. Higher-turbidity removal efficiencies were achieved at 20 and 30 rpm, while TSS removal efficiency was higher for the 50-rpm slow mixing speed. Extended slow mixing time of 30 min yielded better turbidity and TSS removal efficiencies at the slower speeds.

  3. Cyclosporin A preferentially attenuates skeletal slow-twitch muscle regeneration

    Directory of Open Access Journals (Sweden)

    Miyabara E.H.

    2005-01-01

    Full Text Available Calcineurin, a Ca2+/calmodulin-dependent phosphatase, is associated with muscle regeneration via NFATc1/GATA2-dependent pathways. However, it is not clear whether calcineurin preferentially affects the regeneration of slow- or fast-twitch muscles. We investigated the effect of a calcineurin inhibitor, cyclosporin A (CsA, on the morphology and fiber diameter of regenerating slow- and fast-twitch muscles. Adult Wistar rats (259.5 ± 9 g maintained under standard conditions were treated with CsA (20 mg/kg body weight, ip for 5 days, submitted to cryolesion of soleus and tibialis anterior (TA muscles on the 6th day, and then treated with CsA for an additional 21 days. The muscles were removed, weighed, frozen, and stored in liquid nitrogen. Cryolesion did not alter the body weight gain of the animals after 21 days of regeneration (P = 0.001 and CsA significantly reduced the body weight gain (15.5%; P = 0.01 during the same period. All treated TA and soleus muscles showed decreased weights (17 and 29%, respectively, P < 0.05. CsA treatment decreased the cross-sectional area of both soleus and TA muscles of cryoinjured animals (TA: 2108 ± 930 vs 792 ± 640 µm²; soleus: 2209 ± 322 vs 764 ± 439 m²; P < 0.001. Histological sections of both muscles stained with Toluidine blue revealed similar regenerative responses after cryolesion. In addition, CsA was able to minimize these responses, i.e., centralized nuclei and split fibers, more efficiently so in TA muscle. These results indicate that calcineurin preferentially plays a role in regeneration of slow-twitch muscle.

  4. Generalized slow roll for noncanonical kinetic terms

    International Nuclear Information System (INIS)

    Hu, Wayne

    2011-01-01

    We show that the generalized slow roll approach for calculating the power spectrum where the inflationary slow roll parameters are neither small nor slowly varying can be readily extended to models with noncanonical kinetic terms in the inflaton action. For example, rapid sound speed variations can arise in Dirac-Born-Infeld models with features in the warp factor leading to features in the power spectrum. Nonetheless there remains a single source function for deviations that is simply related to the power spectrum. Empirical constraints on this source function can be readily interpreted in the context of features in the inflaton potential or sound speed.

  5. Fast and slow spindles during the sleep slow oscillation: disparate coalescence and engagement in memory processing.

    Science.gov (United States)

    Mölle, Matthias; Bergmann, Til O; Marshall, Lisa; Born, Jan

    2011-10-01

    Thalamo-cortical spindles driven by the up-state of neocortical slow (memory consolidation during sleep. We examined interactions between SOs and spindles in human slow wave sleep, focusing on the presumed existence of 2 kinds of spindles, i.e., slow frontocortical and fast centro-parietal spindles. Two experiments were performed in healthy humans (24.5 ± 0.9 y) investigating undisturbed sleep (Experiment I) and the effects of prior learning (word paired associates) vs. non-learning (Experiment II) on multichannel EEG recordings during sleep. Only fast spindles (12-15 Hz) were synchronized to the depolarizing SO up-state. Slow spindles (9-12 Hz) occurred preferentially at the transition into the SO down-state, i.e., during waning depolarization. Slow spindles also revealed a higher probability to follow rather than precede fast spindles. For sequences of individual SOs, fast spindle activity was largest for "initial" SOs, whereas SO amplitude and slow spindle activity were largest for succeeding SOs. Prior learning enhanced this pattern. The finding that fast and slow spindles occur at different times of the SO cycle points to disparate generating mechanisms for the 2 kinds of spindles. The reported temporal relationships during SO sequences suggest that fast spindles, driven by the SO up-state feed back to enhance the likelihood of succeeding SOs together with slow spindles. By enforcing such SO-spindle cycles, particularly after prior learning, fast spindles possibly play a key role in sleep-dependent memory processing.

  6. Light storage via slow-light four-wave mixing

    International Nuclear Information System (INIS)

    Fan, Yun-Fei; Wang, Hai-Hua; Wei, Xiao-Gang; Li, Ai-Jun; Kang, Zhi-Hui; Wu, Jin-Hui; Zhang, Han-Zhuang; Xu, Huai-Liang; Gao, Jin-Yue

    2012-01-01

    We experimentally demonstrate a light storage via slow-light four-wave mixing in a solid-state medium with a four-level double lambda scheme. Using slow light based on electromagnetically induced transparency, we obtain a slowed four-wave mixing signal pulse together with the slowed probe pulse. During the propagation of light pulses, the storage and retrieval of both the slowed four-wave mixing pulse and the slowed probe pulse are studied by manipulating the intensities of the control fields. -- Highlights: ► A light storage via slow-light four-wave mixing is observed in a solid. ► The probe pulse is slowed under electromagnetically induced transparency. ► A slowed four-wave mixing pulse is obtained by slow light. ► The storage of slowed double pulses is studied.

  7. Polymers having slow release function and their applications

    International Nuclear Information System (INIS)

    Kaetsu, Isao; Yamada, Akio.

    1982-01-01

    The research of giving slow releasing property to drugs by compounding them with suitable matrices and forming has been carried out actively in order to minimize the adverse effect, to reduce the frequency of administration and to improve the bioavailability of such drugs. The slow release function of drugs may be acquired by the copolymerization with synthetic and natural polymers. Drugs are mixed with monomers, and the mixture is polymerized by means of heat, light or radiation (gamma ray or electron beam). Various physical and chemical factors influencing on the rate of release are shown. The compound capsules of drugs and polymers may be used for chemotherapy, enzyme and hormone therapy, immunotherapy, artificial organs, medical and pharmaceutical applications in the form of suppositary, and administration by mucous membrane, subcutaneous and intra-fascia contact or burying. Mytomycin (MMC) of 1.6 mg/kg (LD 50 of i.v. injection) or 3.2 mg/kg (LD 50 x 2) was implanted in the abdomen of dogs. The release of MMC from the implanted capsules was relatively localized to the vicinity of implantation. More hydrophilic polymer (39 % water retention, for example, hydroxyethylmetacrylate polymer) gave more death (toxicity) cases than less hydrophilic one (2 % water retention, for example, diethylglycoldimetacrylate polymer) in the mice with Ehrlich ascites cancer cells, 5 x 10 6 cells/0.2 ml. Because of the nature of locally limited release of the drug, the capsules of anti-cancer drugs, analgesics, antibiotics, hormone, etc. should be delivered to disease foci by means of a fiber scope technique, or intravascular microcapsules. (Yamashita, S.)

  8. Slow evaporation method and enhancement in photoluminescence ...

    Indian Academy of Sciences (India)

    nescence (PL) properties and decay time of phosphors were studied at room temperature. The YPO4 ... Keywords. Slow evaporation method; YPO4 : Eu3+, Bi3+; quenching effect; optical material. 1. ... intensity of Eu3+-doped compounds such as CaMoO4 : Bi3+, .... Figure 4 shows FESEM images of YPO4 : Eu3+ and Bi3+.

  9. Quick-Connect, Slow-Disconnect Bolt

    Science.gov (United States)

    Weddendorf, Bruce

    1995-01-01

    Proposed bolt functions similarly to device described in article "Quick-Connect, Slow-Disconnect Nut" (MFS-28833). Bolt installed in standard threaded hole simply by pushing it into hole. Once inserted, bolt withdrawn only by turning it in conventional way.

  10. A slow component of classic Stroop interference

    NARCIS (Netherlands)

    Phaf, R. Hans; Horsman, Hark H.; van der Moolen, Bas; Roos, Yvo B. W. E. M.; Schmand, Ben

    2010-01-01

    The interference in colour naming may extend beyond critical Stroop trials. This "slow'' effect was first discovered in emotional Stroop tasks, but is extended here to classical Stroop. In two experiments, meaningless coloured letter strings followed a colour word or neutral word. Student

  11. Slow Reading: Reading along "Lectio" Lines

    Science.gov (United States)

    Badley, K. Jo-Ann; Badley, Ken

    2011-01-01

    The medieval monastic movement preserved and developed reading practices--lectio--from ancient Greek pedagogy as a slow, mindful approach to reading for formation. This ancient way of reading, now better known as lectio divina, challenges the fast, pragmatic reading so characteristic of our time. We propose that the present moment may be ripe for…

  12. Slowed ageing, welfare, and population problems.

    Science.gov (United States)

    Wareham, Christopher

    2015-10-01

    Biological studies have demonstrated that it is possible to slow the ageing process and extend lifespan in a wide variety of organisms, perhaps including humans. Making use of the findings of these studies, this article examines two problems concerning the effect of life extension on population size and welfare. The first--the problem of overpopulation--is that as a result of life extension too many people will co-exist at the same time, resulting in decreases in average welfare. The second--the problem of underpopulation--is that life extension will result in too few people existing across time, resulting in decreases in total welfare. I argue that overpopulation is highly unlikely to result from technologies that slow ageing. Moreover, I claim that the problem of underpopulation relies on claims about life extension that are false in the case of life extension by slowed ageing. The upshot of these arguments is that the population problems discussed provide scant reason to oppose life extension by slowed ageing.

  13. Response of electret dosemeter to slow neutrons

    International Nuclear Information System (INIS)

    Ghilardi, A.J.P.; Pela, C.A.; Zimmerman, R.L.

    1987-01-01

    The response of the electret dosemeter to exposition of slow neutrons is studied. Different external coatings are used on the dosemeter (polyethylene, alminium, polyethylene + boron, aluminium + boron) and exposure curves (with and without water) are compared. (M.A.C.) [pt

  14. Analysis of the neutron slowing down equation

    International Nuclear Information System (INIS)

    Sengupta, A.; Karnick, H.

    1978-01-01

    The infinite series solution of the elementary neutron slowing down equation is studied using the theory of entire functions of exponential type and nonharmonic Fourier series. It is shown from Muntz--Szasz and Paley--Wiener theorems, that the set of exponentials ]exp(ilambda/sub n/u) ]/sup infinity//sub n/=-infinity, where ]lambda/sub n/]/sup infinity//sub n/=-infinity are the roots of the transcendental equation in slowing down theory, is complete and forms a basis in a lethargy interval epsilon. This distinctive role of the maximum lethargy change per collision is due to the Fredholm character of the slowing down operator which need not be quasinilpotent. The discontinuities in the derivatives of the collision density are examined by treating the slowing down equation in its differential-difference form. The solution (Hilbert) space is the union of a countable number of subspaces L 2 (-epsilon/2, epsilon/2) over each of which the exponential functions are complete

  15. Probabilistic Slow Features for Behavior Analysis

    NARCIS (Netherlands)

    Zafeiriou, Lazaros; Nicolaou, Mihalis A.; Zafeiriou, Stefanos; Nikitidis, Symeon; Pantic, Maja

    A recently introduced latent feature learning technique for time-varying dynamic phenomena analysis is the so-called slow feature analysis (SFA). SFA is a deterministic component analysis technique for multidimensional sequences that, by minimizing the variance of the first-order time derivative

  16. Learning slow features for behavior analysis

    NARCIS (Netherlands)

    Zafeiriou, Lazaros; Nicolaou, Mihalis A.; Zafeiriou, Stefanos; Nikitids, Symeon; Pantic, Maja

    2013-01-01

    A recently introduced latent feature learning technique for time varying dynamic phenomena analysis is the socalled Slow Feature Analysis (SFA). SFA is a deterministic component analysis technique for multi-dimensional sequences that by minimizing the variance of the first order time derivative

  17. Proton energy dependence of slow neutron intensity

    International Nuclear Information System (INIS)

    Teshigawara, Makoto; Harada, Masahide; Watanabe, Noboru; Kai, Tetsuya; Sakata, Hideaki; Ikeda, Yujiro

    2001-01-01

    The choice of the proton energy is an important issue for the design of an intense-pulsed-spallation source. The optimal proton beam energy is rather unique from a viewpoint of the leakage neutron intensity but no yet clear from the slow-neutron intensity view point. It also depends on an accelerator type. Since it is also important to know the proton energy dependence of slow-neutrons from the moderators in a realistic target-moderator-reflector assembly (TMRA). We studied on the TMRA proposed for Japan Spallation Neutron Source. The slow-neutron intensities from the moderators per unit proton beam power (MW) exhibit the maximum at about 1-2 GeV. At higher proton energies the intensity per MW goes down; at 3 and 50 GeV about 0.91 and 0.47 times as low as that at 1 GeV. The proton energy dependence of slow-neutron intensities was found to be almost the same as that of total neutron yield (leakage neutrons) from the same bare target. It was also found that proton energy dependence was almost the same for the coupled and decoupled moderators, regardless the different moderator type, geometry and coupling scheme. (author)

  18. Preliminary characterization of slow growing rhizobial strains ...

    African Journals Online (AJOL)

    In this paper, we did some preliminary characterization of six slow growing rhizobial strains, isolated from Retama monosperma (L.) Boiss. root nodules sampled from 3 sites along the coast of Oran (CapeFalcon, Bousfer and MersElHadjadj) in Northwestern Algeria. Results of this study showed that all strains had a very ...

  19. Preliminary characterization of slow growing rhizobial strains ...

    African Journals Online (AJOL)

    COMPAQ

    2016-05-18

    May 18, 2016 ... strains had a very slow growth rate in yeast malt (YM) agar medium, forming colonies less than 1 mm in ... dominant genus of symbiotic nitrogen-fixing bacteria ... Single colonies were picked up and checked for purity by.

  20. Polymeric membrane studied using slow positron beam

    International Nuclear Information System (INIS)

    Hung, W.-S.; Lo, C.-H.; Cheng, M.-L.; Chen Hongmin; Liu Guang; Chakka, Lakshmi; Nanda, D.; Tung, K.-L.; Huang, S.-H.; Lee, Kueir-Rarn; Lai, J.-Y.; Sun Yiming; Yu Changcheng; Zhang Renwu; Jean, Y.C.

    2008-01-01

    A radioisotope slow positron beam has been built at the Chung Yuan Christian University in Taiwan for the research and development in membrane science and technology. Doppler broadening energy spectra and positron annihilation lifetime have been measured as a function of positron energy up to 30 keV in a polyamide membrane prepared by the interfacial polymerization between triethylenetetraamine (TETA) and trimesoyl chloride (TMC) on modified porous polyacrylonitrile (PAN) asymmetric membrane. The multilayer structures and free-volume depth profile for this asymmetric membrane system are obtained. Positron annihilation spectroscopy coupled with a slow beam could provide new information about size selectivity of transporting molecules and guidance for molecular designs in polymeric membranes

  1. A tilted transversely isotropic slowness surface approximation

    KAUST Repository

    Stovas, A.

    2012-05-09

    The relation between vertical and horizontal slownesses, better known as the dispersion relation, for transversely isotropic media with a tilted symmetry axis (TTI) requires solving a quartic polynomial equation, which does not admit a practical explicit solution to be used, for example, in downward continuation. Using a combination of the perturbation theory with respect to the anelliptic parameter and Shanks transform to improve the accuracy of the expansion, we develop an explicit formula for the vertical slowness that is highly accurate for all practical purposes. It also reveals some insights into the anisotropy parameter dependency of the dispersion relation including the low impact that the anelliptic parameter has on the vertical placement of reflectors for a small tilt in the symmetry angle. © 2012 European Association of Geoscientists & Engineers.

  2. Slow and fast light in semiconductor waveguides

    DEFF Research Database (Denmark)

    Mørk, Jesper; Hansen, Per Lunnemann; Xue, Weiqi

    2010-01-01

    Investigations of slow and fast light effects in semiconductor waveguides entail interesting physics and point to a number of promising applications. In this review we give an overview of recent progress in the field, in particular focusing on the physical mechanisms of electromagnetically induced...... transparency and coherent population oscillations. While electromagnetically induced transparency has been the most important effect in realizing slowdown effects in atomic gasses, progress has been comparatively slow in semiconductors due to inherent problems of fast dephasing times and inhomogeneous...... broadening in quantum dots. The physics of electromagnetically induced transparency in semiconductors is discussed, emphasizing these limitations and recent suggestions for overcoming them. On the other hand, the mechanism of coherent population oscillations relies on wave mixing effects and is well suited...

  3. Slow Invariant Manifolds in Chemically Reactive Systems

    Science.gov (United States)

    Paolucci, Samuel; Powers, Joseph M.

    2006-11-01

    The scientific design of practical gas phase combustion devices has come to rely on the use of mathematical models which include detailed chemical kinetics. Such models intrinsically admit a wide range of scales which renders their accurate numerical approximation difficult. Over the past decade, rational strategies, such as Intrinsic Low Dimensional Manifolds (ILDM) or Computational Singular Perturbations (CSP), for equilibrating fast time scale events have been successfully developed, though their computation can be challenging and their accuracy in most cases uncertain. Both are approximations to the preferable slow invariant manifold which best describes how the system evolves in the long time limit. Strategies for computing the slow invariant manifold are examined, and results are presented for practical combustion systems.

  4. Slowed demand ushers in summer season

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    This article is the June 1996 market summary in uranium market. During this reporting period, there were six deals in the U3O8 spot market and three long-term deals for U3O8. There were four deals for UF6 conversion, and the spot market for uranium separation services had no transactions. This was little change from the previous month's activities, and this slowness was reflected in the price trends of little or no increase

  5. Fundamental research with polarized slow neutrons

    International Nuclear Information System (INIS)

    Krupchitsky, P.A.

    1987-01-01

    In the last twenty years polarized beams of slow neutrons have been used effectively in fundamental research in nuclear physics. This book gives a thorough introduction to these experimental methods including the most recent techniques of generating and analyzing polarized neutron beams. It clearly shows the close relationship between elementary particle physics and nuclear physics. The book not only addresses specialists but also those interested in the foundations of elementary particle and nuclear physics. With 42 figs

  6. Testing algorithms for critical slowing down

    Directory of Open Access Journals (Sweden)

    Cossu Guido

    2018-01-01

    Full Text Available We present the preliminary tests on two modifications of the Hybrid Monte Carlo (HMC algorithm. Both algorithms are designed to travel much farther in the Hamiltonian phase space for each trajectory and reduce the autocorrelations among physical observables thus tackling the critical slowing down towards the continuum limit. We present a comparison of costs of the new algorithms with the standard HMC evolution for pure gauge fields, studying the autocorrelation times for various quantities including the topological charge.

  7. SOFTWARE Manual for VMM3 Slow Control

    CERN Document Server

    Guth, Manuel

    2017-01-01

    For the New Small Wheel upgrade of the ATLAS detector a new readout chip, called VMM3(a), was developed. In order to provide this new technology to a larger community, the RD51 collaboration is integrating the VMM3 in their scalable readout system (SRS). For this purpose, a new slow control and calibration tool is necessary. This new software was developed and improved within a CERN Summer Student project.

  8. Theory of a slow-light catastrophe

    International Nuclear Information System (INIS)

    Leonhardt, Ulf

    2002-01-01

    In diffraction catastrophes such as the rainbow, the wave nature of light resolves ray singularities and draws delicate interference patterns. In quantum catastrophes such as the black hole, the quantum nature of light resolves wave singularities and creates characteristic quantum effects related to Hawking radiation. This paper describes the theory behind a recent proposal [U. Leonhardt, Nature (London) 415, 406 (2002)] to generate a quantum catastrophe of slow light

  9. Theory of a slow-light catastrophe

    Science.gov (United States)

    Leonhardt, Ulf

    2002-04-01

    In diffraction catastrophes such as the rainbow, the wave nature of light resolves ray singularities and draws delicate interference patterns. In quantum catastrophes such as the black hole, the quantum nature of light resolves wave singularities and creates characteristic quantum effects related to Hawking radiation. This paper describes the theory behind a recent proposal [U. Leonhardt, Nature (London) 415, 406 (2002)] to generate a quantum catastrophe of slow light.

  10. Theory of a Slow-Light Catastrophe

    OpenAIRE

    Leonhardt, Ulf

    2001-01-01

    In diffraction catastrophes such as the rainbow the wave nature of light resolves ray singularities and draws delicate interference patterns. In quantum catastrophes such as the black hole the quantum nature of light resolves wave singularities and creates characteristic quantum effects related to Hawking radiation. The paper describes the theory behind a recent proposal [U. Leonhardt, arXiv:physics/0111058, Nature (in press)] to generate a quantum catastrophe of slow light.

  11. Magnetic energy analyser for slow electrons

    International Nuclear Information System (INIS)

    Limberg, W.

    1974-08-01

    A differential spectrometer with high time and energy resolution has been developed using the principle of energy analysis with a longitudinal homogeneous magnetic field. This way it is possible to measure the energy distribution of low energy electrons (eV-range) in the presence of high energy electrons without distortions by secondary electrons. The functioning and application of the analyzer is demonstrated by measuring the energy distributions of slow electrons emitted by a filament. (orig.) [de

  12. γ-ray emission from slow pulsars

    International Nuclear Information System (INIS)

    Morini, M.; Treves, A.

    1981-01-01

    The scope of this communication is to calculate the expected γ-ray flux from slow pulsars, neglecting the problem of the reliability of the observations. The key hypothesis is that since the γ-ray luminosity is a substantial fraction of Lsub(T) (the intrinsic energy loss), it should be produced in the vicinity of the speed of light radius. This comes from the well known argument of simultaneous conservation of energy and angular momentum. (Auth.)

  13. Slowing down modernity: A critique : A critique

    OpenAIRE

    Vostal , Filip

    2017-01-01

    International audience; The connection between modernization and social acceleration is now a prominent theme in critical social analysis. Taking a cue from these debates, I explore attempts that aim to 'slow down modernity' by resisting the dynamic tempo of various social processes and experiences. The issue of slowdown now accounts for a largely unquestioned measure, expected to deliver unhasty tempo conditioning good and ethical life, mental well-being and accountable democracy. In princip...

  14. Effects of telmisartan combined with nifedipine controlled release tablet on inflammatory factors, vascular endothelial function and left ventricular function in patients with coronary heart disease with mild to moderate hypertension

    Directory of Open Access Journals (Sweden)

    Feng Guo

    2017-10-01

    Full Text Available Objective: To investigate the effect of telmisartan combined with Nifedipine Controlled Release Tablet on inflammatory factors, vascular endothelial function and left ventricular function in patients with coronary heart disease with mild to moderate hypertension. Methods: A total of 92 cases of patients with coronary heart disease with mild to moderate hypertension were selected as the object of observation, according to the random data table, they were divided into the control group (n=46 and observation group (n=46, and patients in the control group were treated with Nifedipine Controlled Release Table therapy, on this basis, the observation group patients were given telmisartan treatment, two groups were treated for 6 months. The levels of the blood pressure, inflammatory factors, vascular endothelial function and left ventricular function compared between the two groups before and after treatment. Results: There were no significant differences in the levels of SBP, DBP, hs-CRP, TNF-α, NO, ET-1, LVEF, LVEDD and LVESD in the two groups before treatment. After treatment, two groups of SBP, DBP, hs-CRP, TNF-α, ET-1, LVEDD and LVESD levels were significantly lower than those in the same group before treatment, and after treatment, the levels of SBP, DBP, hs-CRP, TNF-α, ET-1 and LVESD in the observation group were significantly lower than those in the control group, while there were no significant difference in the level of LVEDD between the two groups after treatment; Compared with level in the group before treatment, the levels of NO and LVEF in the two groups were significantly increased, and the observation group [(82.13±19.01 µmol/L, (52.83±7.45%] was significantly higher than the control group [(67.37±13.08 µmol/L, (49.47±6.96%]. Conclusion: Telmisartan combined with Nifedipine Controlled Release Table in treating coronary heart disease with mild to moderate hypertension, can effectively control blood pressure, reduce the

  15. Myasthenia Gravis (MG): Medical Management

    Science.gov (United States)

    ... take effect, prior to surgery or for myasthenic crisis. However, some people receive regular plasmapheresis or IVIg as a supplement to immunosuppressant drugs. Pregnancy In rare cases, pregnancy appears to trigger the onset of MG. ...

  16. Dilution and slow injection reduces the incidence of rocuronium-induced withdrawal movements in children

    OpenAIRE

    Shin, Young Hee; Kim, Chung Su; Lee, Jong-Hwan; Sim, Woo Seog; Ko, Justin Sangwook; Cho, Hyun Sung; Jeong, Hui Yeon; Lee, Hye Won; Kim, Sang Hyun

    2011-01-01

    Background The aim of this study was to evaluate whether slow injection of diluted rocuronium could reduce rocuronium-induced withdrawal movements effectively in children. Methods After loss of consciousness, rocuronium 0.6 mg/kg was administered into 171 children according to the pre-assigned groups as follows: Group CF, injection of non-diluted rocuronium over 5 seconds; Group CS, injection of non-diluted rocuronium over 1 minute; Group DF, injection of diluted rocuronium (10 times) over 5 ...

  17. Nonlinear dynamical triggering of slow slip

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Paul A [Los Alamos National Laboratory; Knuth, Matthew W [WISCONSIN; Kaproth, Bryan M [PENN STATE; Carpenter, Brett [PENN STATE; Guyer, Robert A [Los Alamos National Laboratory; Le Bas, Pierre - Yves [Los Alamos National Laboratory; Daub, Eric G [Los Alamos National Laboratory; Marone, Chris [PENN STATE

    2010-12-10

    Among the most fascinating, recent discoveries in seismology have been the phenomena of triggered slip, including triggered earthquakes and triggered-tremor, as well as triggered slow, silent-slip during which no seismic energy is radiated. Because fault nucleation depths cannot be probed directly, the physical regimes in which these phenomena occur are poorly understood. Thus determining physical properties that control diverse types of triggered fault sliding and what frictional constitutive laws govern triggered faulting variability is challenging. We are characterizing the physical controls of triggered faulting with the goal of developing constitutive relations by conducting laboratory and numerical modeling experiments in sheared granular media at varying load conditions. In order to simulate granular fault zone gouge in the laboratory, glass beads are sheared in a double-direct configuration under constant normal stress, while subject to transient perturbation by acoustic waves. We find that triggered, slow, silent-slip occurs at very small confining loads ({approx}1-3 MPa) that are smaller than those where dynamic earthquake triggering takes place (4-7 MPa), and that triggered slow-slip is associated with bursts of LFE-like acoustic emission. Experimental evidence suggests that the nonlinear dynamical response of the gouge material induced by dynamic waves may be responsible for the triggered slip behavior: the slip-duration, stress-drop and along-strike slip displacement are proportional to the triggering wave amplitude. Further, we observe a shear-modulus decrease corresponding to dynamic-wave triggering relative to the shear modulus of stick-slips. Modulus decrease in response to dynamical wave amplitudes of roughly a microstrain and above is a hallmark of elastic nonlinear behavior. We believe that the dynamical waves increase the material non-affine elastic deformation during shearing, simultaneously leading to instability and slow-slip. The inferred

  18. Slow movement execution in event-related potentials (P300).

    Science.gov (United States)

    Naruse, Kumi; Sakuma, Haruo; Hirai, Takane

    2002-02-01

    We examined whether slow movement execution has an effect on cognitive and information processing by measuring the P300 component. 8 subjects performed a continuous slow forearm rotational movement using 2 task speeds. Slow (a 30-50% decrease from the subject's Preferred speed) and Very Slow (a 60-80% decrease). The mean coefficient of variation for rotation speed under Very Slow was higher than that under Slow, showing that the subjects found it difficult to perform the Very Slow task smoothly. The EEG score of alpha-1 (8-10 Hz) under Slow Condition was increased significantly more than under the Preferred Condition; however, the increase under Very Slow was small when compared with Preferred. After performing the task. P300 latency under Very Slow increased significantly as compared to that at pretask. Further, P300 amplitude decreased tinder both speed conditions when compared to that at pretask, and a significant decrease was seen under the Slow Condition at Fz, whereas the decrease under the Very Slow Condition was small. These differences indicated that a more complicated neural composition and an increase in subjects' attention might have been involved when the task was performed under the Very Slow Condition. We concluded that slow movement execution may have an influence on cognitive function and may depend on the percentage of decrease from the Preferred speed of the individual.

  19. In vitro evaluation of extemporaneously compounded slow-release capsules containing morphine sulfate or oxycodone hydrochloride.

    Science.gov (United States)

    Glowiak, Dana L; Green, Julie L; Bowman, Bill J

    2005-01-01

    The in vitro performance of extemporaneously compounded morphine sulfate and oxycodone hydrochloride slow-release capsules was evaluated. Capsules containing varying amoutns of morphine sulfate (15, 60, 200 mg) or oxycodone hydrochloride (10, 80, 200 mg) were prepared and provided by a Phoenix, Arizona, pharmacy. The capsules also contained 40% Methocel E4M Premium to slow the release of their active ingredient and sufficient lactose to fill the capsules. Three batches of each capsule strength were prepared, and replicates from each batch were evlauated using United Stated Pharmacopeia dissolution apparatus II. Samples were taken at regular time intervals over 24 hours. After 1 hour the pH of the dissolution medium was adjusted form 1.2 to 4.0, and after 2 hours the pH was adjusted to 6.8. The amount of drug released at each time point was determined spectrophotometrically. The compounded capsules released 14% to 23%, 67% to 85% and 93% to 98% of their active ingredient after 0.5, 4 and 12 hours, respectively. The relative standard deviations between the replicates from each batch were less than 10% for most time points. The percent of drug released over the first 4 hours was linear (r squared = 0.9409-0.9999) when plotted versus time 1/2, indicating adherence to the simplified Higuchi model. Statistical analysis of the Higuchi dissolution constants indicated a significant difference (P less than 0.05) between batch No.3 and the other two batches of 200-mg oxycodone hydrochloride capsules. There was also a statistical difference between most of the Higuchi dissolution constants for the different-strength slow-release capsules and most slow-release capsules and equivalent strength controlled-release manufactured tablets (P less than 0.05). Using 40% Methocel E4M Premium slowed the release of morphine sulfate and oxycodone hydrochloride from extemporaneously compounded capsules. The in vitro performance of the slow-release capsules showed little intrabatch variation

  20. Counting graphene layers with very slow electrons

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Ludĕk; Mikmeková, Eliška; Müllerová, Ilona [Institute of Scientific Instruments AS CR, v.v.i., Královopolská 147, 61264 Brno (Czech Republic); Lejeune, Michaël [Laboratoire de Physique de la Matière Condensée, Faculté des Sciences d' Amiens, Universite de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens Cedex 2 (France)

    2015-01-05

    The study aimed at collection of data regarding the transmissivity of freestanding graphene for electrons across their full energy scale down to the lowest energies. Here, we show that the electron transmissivity of graphene drops with the decreasing energy of the electrons and remains below 10% for energies below 30 eV, and that the slow electron transmissivity value is suitable for reliable determination of the number of graphene layers. Moreover, electrons incident below 50 eV release adsorbed hydrocarbon molecules and effectively clean graphene in contrast to faster electrons that decompose these molecules and create carbonaceous contamination.

  1. 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.

  2. Quasistatic modelling of the coaxial slow source

    International Nuclear Information System (INIS)

    Hahn, K.D.; Pietrzyk, Z.A.; Vlases, G.C.

    1986-01-01

    A new 1-D Lagrangian MHD numerical code in flux coordinates has been developed for the Coaxial Slow Source (CSS) geometry. It utilizes the quasistatic approximation so that the plasma evolves as a succession of equilibria. The P=P (psi) equilibrium constraint, along with the assumption of infinitely fast axial temperature relaxation on closed field lines, is incorporated. An axially elongated, rectangular plasma is assumed. The axial length is adjusted by the global average condition, or assumed to be fixed. In this paper predictions obtained with the code, and a limited amount of comparison with experimental data are presented

  3. Hot big bang or slow freeze?

    Science.gov (United States)

    Wetterich, C.

    2014-09-01

    We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze - a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple ;crossover model; without a big bang singularity. In the infinite past space-time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe.

  4. Lead Slowing Down Spectrometer Status Report

    International Nuclear Information System (INIS)

    Warren, Glen A.; Anderson, Kevin K.; Bonebrake, Eric; Casella, Andrew M.; Danon, Yaron; Devlin, M.; Gavron, Victor A.; Haight, R.C.; Imel, G.R.; Kulisek, Jonathan A.; O'Donnell, J.M.; Weltz, Adam

    2012-01-01

    This report documents the progress that has been completed in the first half of FY2012 in the MPACT-funded Lead Slowing Down Spectrometer project. Significant progress has been made on the algorithm development. We have an improve understanding of the experimental responses in LSDS for fuel-related material. The calibration of the ultra-depleted uranium foils was completed, but the results are inconsistent from measurement to measurement. Future work includes developing a conceptual model of an LSDS system to assay plutonium in used fuel, improving agreement between simulations and measurement, design of a thorium fission chamber, and evaluation of additional detector techniques.

  5. Simulation of Cu-Mg metallic glass: Thermodynamics and structure

    DEFF Research Database (Denmark)

    Bailey, Nicholas; Schiøtz, Jakob; Jacobsen, Karsten Wedel

    2004-01-01

    We have obtained effective medium theory interatomic potential parameters suitable for studying Cu-Mg metallic glasses. We present thermodynamic and structural results from simulations of such glasses over a range of compositions. We have produced low-temperature configurations by cooling from...... the melt at as slow a rate as practical, using constant temperature and pressure molecular dynamics. During the cooling process we have carried out thermodynamic analyses based on the temperature dependence of the enthalpy and its derivative, the specific heat, from which the glass transition temperature...

  6. Sustainable Development of Slow Fashion Businesses: Customer Value Approach

    Directory of Open Access Journals (Sweden)

    Sojin Jung

    2016-06-01

    Full Text Available As an alternative to the prevalent fast fashion model, slow fashion has emerged as a way of enhancing sustainability in the fashion industry, yet how slow fashion can enhance profitability is still largely unknown. Based on a customer value creation framework, this study empirically tested a structural model that specified the slow fashion attributes that contribute to creating perceived customer value, which subsequently increases a consumer’s intention to buy and pay a price premium for slow fashion products. An analysis of 221 U.S. consumer data revealed that delivering exclusive product value is significantly critical in creating customer value for slow fashion, and customer value, in turn, positively affects consumers’ purchase intentions. Further analysis also revealed that different slow fashion attributes distinctively affect customer value. This provides potential strategies on which slow fashion businesses can focus to secure an economically sustainable business model, thereby continuously improving environmental and social sustainability with the slow fashion ideal.

  7. Slow-light dynamics in nonlinear periodic waveguides couplers

    DEFF Research Database (Denmark)

    Sukhorukov, A.A.; Ha, S.; Powell, D.A.

    2009-01-01

    We predict pulse switching and reshaping through nonlinear mixing of two slow-light states with different phase velocities in the same frequency range, and report on the first experimental observation of slow-light tunneling between coupled periodic waveguides.......We predict pulse switching and reshaping through nonlinear mixing of two slow-light states with different phase velocities in the same frequency range, and report on the first experimental observation of slow-light tunneling between coupled periodic waveguides....

  8. Slow-light effects in photonic crystal membrane lasers

    DEFF Research Database (Denmark)

    Xue, Weiqi; Yu, Yi; Ottaviano, Luisa

    2015-01-01

    In this paper, we present a systematic investigation of photonic crystal cavity laser operating in the slow-light regime. The dependence of lasing threshold on the effect of slow-light will be particularly highlighted.......In this paper, we present a systematic investigation of photonic crystal cavity laser operating in the slow-light regime. The dependence of lasing threshold on the effect of slow-light will be particularly highlighted....

  9. Nonlinear Gain Saturation in Active Slow Light Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2013-01-01

    We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated.......We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated....

  10. Factors Contributing Decreased Performance Of Slow Learners

    Directory of Open Access Journals (Sweden)

    Dr. L. Kannan

    2015-03-01

    Full Text Available Back ground Even experienced teaching faculty and administrators can be challenged by learners who have not able to perform up to expected need in their annual performance of their students these students are called as slow learnersStruggle learners. There should be a designed study to foster discussion about diagnosing particular problems that contribute with meeting objectives of slow learners. Methodology The study was performed on the entire current first year of Medical students were all the three internal assessments of 250 students performance is taken in to consideration for the study. This study is of cross section type.After obtaining the list of all students marks in internal examination from medical education unit supporting mentors are contacted to meet the students and confidentiality is maintained throughout the study. After obtaining informed consent a questionnaire was administered to the students by the investigator. The questionnaire contains the following sections. Section I will be on the background characteristics of the student name age sex type of family. Section II will be on the details of their learning capabilities. Section III will focus on the awareness of the slow learners in which the precipitating factors contributing to them. Results The prevalence of slow learners as low achievers were contributed to be 32.4 percentages.The performance of the students is based on combination of all three internal assessment marks including theory and practical performance. In this the students age ranges from 17 to 21 years the mean age of student was contributed to be 17.81 and majority of the students were in the age group of 18 years which contributed to be 16867.2.In the present study majority were males 13252.8 compared to females 11847.2.but when study is compared to percentage of attendance majority of the individual 15177 scored more than 50 percentage of marks have more than 80 percentage of attendance but when

  11. Good, Clean, Fair: The Rhetoric of the Slow Food Movement

    Science.gov (United States)

    Schneider, Stephen

    2008-01-01

    This article outlines the origins of the Slow Food movement before examining the ways in which Slow Food rhetoric seeks to redefine gastronomy and combat the more deleterious effects of globalization. In articulating a new gastronomy, Slow Food founder Carlo Petrini attempts to reconstruct the gastronomy of Jean Anthelme Brillat-Savarin, at once…

  12. Oxidative dehydrogenation of propane with K-MoO3/MgAl2O4 ...

    Indian Academy of Sciences (India)

    with potassium addition due to interaction with MoO3 sites. For this reason total ... in recent years.1–3 In ODH of propane reaction, there ... heptamolybdate (Merck), dissolved in water and Mg- .... Alkali metal promotion slows down the reduc-.

  13. Hot big bang or slow freeze?

    Energy Technology Data Exchange (ETDEWEB)

    Wetterich, C.

    2014-09-07

    We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze — a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple “crossover model” without a big bang singularity. In the infinite past space–time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe.

  14. Interaction of slow electrons with surfaces. II

    International Nuclear Information System (INIS)

    Komolov, S.A.; Chadderton, L.T.

    1976-01-01

    Total current spectroscopy (TCS) has been used to study the growth of films of gold and silver on (100) vanadium surfaces. A slow transition from TCS curves characteristic of vanadium to curves characteristic of the noble metals is observed, accompanied by an increase in the net work function - more rapid for silver than for gold. Vanadium characteristics are lost from the TCS curves for mean overlayer thicknesses > approximately 15A, and a simple analysis shows that the thickness of the surface zone from which TCS signals originate is approximately given by the electron mean free path. Observations of progressive attenuation of a characteristic vanadium feature with increasing mean thickness of overlayer permits separation into stages of nucleation and growth. There is a critical nucleus size of approximately 2A for silver and approximately 4A for gold. (Auth.)

  15. Limits of slow light in photonic crystals

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Xiao, Sanshui; Mortensen, N. Asger

    2008-01-01

    in the group velocity acquiring a finite value above zero at the band-gap edges while attaining uperluminal values within the band gap. Simple scalings of the minimum and maximum group velocities with the imaginary part of the dielectric function or, equivalently, the linewidth of the broadened states......While ideal photonic crystals would support modes with a vanishing group velocity, state-of-the-art structures have still only provided a slow down by roughly two orders of magnitude. We find that the induced density of states caused by lifetime broadening of the electromagnetic modes results...... are presented. The results obtained are entirely general and may be applied to any effect which results in a broadening of the electromagnetic states, such as loss, disorder, and finite-size effects. This significantly limits the reduction in group velocity attainable via photonic crystals....

  16. Slow neutron scattering by water molecules

    Energy Technology Data Exchange (ETDEWEB)

    Stancic, V [Boris Kidric Institute of Nuclear Sciences Vinca, Beograd (Yugoslavia)

    1970-07-01

    In this work some new, preliminary formulae for slow neutron scattering cross section calculation by heavy and light water molecules have been done. The idea was to find, from the sum which exists in well known Nelkin model, other cross sections in a more simple analytical form, so that next approximations may be possible. In order to sum a series it was starting from Euler-Mclaurin formula. Some new summation formulae have been derived there, and defined in two theorems. Extensive calculations, especially during the evaluation of residues, have been made at the CDC 3600 computer. validation of derived formulae was done by comparison with the BNL-325 results. Good agreement is shown. (author)

  17. Acoustic slow waves and the consolidation transition

    International Nuclear Information System (INIS)

    Johnson, D.L.; Plona, T.J.

    1982-01-01

    We have investigated the ultrasonic properties of unconsolidated (loose) glass beads and of lightly fused (consolidated) glass beads when the pore space is saturated with water. At a frequency of 500 kHz we have observed a single compressional wave in the former whose speed is 1.79 km/s and two distinct compressional waves with speeds 2.81 km/s and 0.96 km/s in the latter. The Biot theory is shown to give an accurate description of this phenomenon. We also analyze the acoustics of low temperature He ii in packed powder superleaks; either the fast wave for unconsolidated systems or the slow wave in a highly consolidated (fused) frame may be considered to be the 4th sound mode. In all such systems, the acoustic properties can be very simply understood by considering the velocities of propagation as continuous functions of the elastic moduli of the solid skeletal frames

  18. Hot big bang or slow freeze?

    International Nuclear Information System (INIS)

    Wetterich, C.

    2014-01-01

    We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze — a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple “crossover model” without a big bang singularity. In the infinite past space–time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe

  19. Slow speed object detection for haul trucks

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-09-15

    Caterpillar integrates radar technology with its current camera based system. Caterpillar has developed the Integrated Object Detection System, a slow speed object detection system for mining haul trucks. Object detection is a system that aids the truck operator's awareness of their surroundings. The system consists of a color touch screen display along with medium- and short-range radar as well as cameras, harnesses and mounting hardware. It is integrated into the truck's Work Area Vision System (WAVS). After field testing in 2007, system commercialization began in 2008. Prototype systems are in operation in Australia, Utah and Arizona and the Integrated Object Detection System will be available in the fourth quarter of 2009 and on production trucks 785C, 789C, 793D and 797B. The article is adapted from a presentation by Mark Richards of Caterpillar to the Haulage & Loading 2009 conference, May, held in Phoenix, AZ. 1 fig., 5 photos.

  20. Slow neutron scattering by water molecules

    International Nuclear Information System (INIS)

    Stancic, V.

    1970-01-01

    In this work some new, preliminary formulae for slow neutron scattering cross section calculation by heavy and light water molecules have been done. The idea was to find, from the sum which exists in well known Nelkin model, other cross sections in a more simple analytical form, so that next approximations may be possible. In order to sum a series it was starting from Euler-Mclaurin formula. Some new summation formulae have been derived there, and defined in two theorems. Extensive calculations, especially during the evaluation of residues, have been made at the CDC 3600 computer. validation of derived formulae was done by comparison with the BNL-325 results. Good agreement is shown. (author)

  1. Hot big bang or slow freeze?

    Directory of Open Access Journals (Sweden)

    C. Wetterich

    2014-09-01

    Full Text Available We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze — a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple “crossover model” without a big bang singularity. In the infinite past space–time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe.

  2. Slow creep in soft granular packings.

    Science.gov (United States)

    Srivastava, Ishan; Fisher, Timothy S

    2017-05-14

    Transient creep mechanisms in soft granular packings are studied numerically using a constant pressure and constant stress simulation method. Rapid compression followed by slow dilation is predicted on the basis of a logarithmic creep phenomenon. Characteristic scales of creep strain and time exhibit a power-law dependence on jamming pressure, and they diverge at the jamming point. Microscopic analysis indicates the existence of a correlation between rheology and nonaffine fluctuations. Localized regions of large strain appear during creep and grow in magnitude and size at short times. At long times, the spatial structure of highly correlated local deformation becomes time-invariant. Finally, a microscale connection between local rheology and local fluctuations is demonstrated in the form of a linear scaling between granular fluidity and nonaffine velocity.

  3. [Titration comparative study of TOPINA Tablets in patients with localization related epilepsy: double-blind comparative study by rapid and slow titration methods].

    Science.gov (United States)

    Kaneko, Sunao; Inoue, Yushi; Sasagawa, Mutsuo; Kato, Masaaki

    2012-04-01

    To compare the tolerability and efficacy of two titration methods (rapid and slow titration) for TOPINA Tablets with different dosages and periods of escalation, a double-blind comparative study was conducted in patients with localization-related epilepsy. A total of 183 patients were randomized to either rapid titration (initial dosage 100 mg/day increased by 100-200 mg at weekly intervals) or to slow titration (initial dosage 50 mg/day increased in 50 mg/day increments at weekly intervals). TOPINA Tablets were administered for 12 weeks to the maximum dosage of 400 mg/day. The incident of adverse events leading to treatment interruptions or withdrawals was 18.9% in rapid titration and 14.8% in slow titration, with no statistical significance (p = 0.554). The incident of adverse events and adverse reactions of slow titration was slightly lower than that of rapid titration. The common adverse events and adverse reactions reported in the two titration methods were comparable and were well tolerated. On the other hand, the efficacy of slow titration, percent reduction in seizure rate and responder rate, was comparable with that of rapid titration. In conclusion, there were no significant differences of therapeutic response to TOPINA Tablets between the two titration methods.

  4. Benefit of slow titration of paroxetine to treat depression in the elderly.

    Science.gov (United States)

    Olgiati, Paolo; Bajo, Emanuele; Serretti, Alessandro

    2014-11-01

    Paroxetine is commonly used to treat depression in the elderly; however, titration issues have been raised. Rapid titration may lead to increased anxiety and early dropout. The aim of this cost-utility analysis was to compare the potential benefit of standard (10 mg the first day) versus slow titration (2.5 mg gradually increased). Clinical analysis was based on a naturalistic trial integrated with a decision-analytic model representing second treatments for those who initially did not respond and for dropout cases. Treatment setting was a public outpatient center for mental disorders in Italy. Service use data were estimated from best practice guidelines, whereas costs (Euros; 2012) were retrieved from Italian official sources. Slow titration approach produced 0.031 more quality-adjusted life years (remission rate: 57% vs 44% in standard titration group) at an incremental cost of €5.53 (generic paroxetine) and €54.54 (brand paroxetine syrup). Incremental cost-effectiveness ratio (ICER) values were €159 and €1768, respectively, in favor of slow titration approach. Cost-effectiveness threshold, defined as ICER titration of paroxetine in older depressed patients. However, these findings, in part based on simulated data, need to be replicated in clinical trials. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Mechanism of Mg2+-Accompanied Product Release in Sugar Nucleotidyltransferases.

    Science.gov (United States)

    Vithani, Neha; Ankush Jagtap, Pravin Kumar; Verma, Sunil Kumar; Tripathi, Ravi; Awasthi, Shalini; Nair, Nisanth N; Prakash, Balaji

    2018-03-06

    The nucleotidyl transfer reaction, catalyzed by sugar nucleotidyltransferases (SNTs), is assisted by two active site Mg 2+ ions. While studying this reaction using X-ray crystallography, we captured snapshots of the pyrophosphate (product) as it exits along a pocket. Surprisingly, one of the active site Mg 2+ ions remains coordinated to the exiting pyrophosphate. This hints at the participation of Mg 2+ in the process of product release, besides its role in catalyzing nucleotidyl transfer. These observations are further supported by enhanced sampling molecular dynamics simulations. Free energy computations suggest that the product release is likely to be rate limiting in SNTs, and the origin of the high free energy barrier for product release could be traced back to the "slow" conformational change of an Arg residue at the exit end of the pocket. These results establish a dual role for Mg 2+ , and propose a general mechanism of product release during the nucleotidyl transfer by SNTs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. In vitro study of nanostructured diopside coating on Mg alloy orthopedic implants

    International Nuclear Information System (INIS)

    Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Vashaee, Daryoosh; Tayebi, Lobat

    2014-01-01

    The high corrosion rate of Mg alloys has hindered their application in various areas, particularly for orthopedic applications. In order to decrease the corrosion rate and to improve the bioactivity, mechanical stability and cytocompatibility of the Mg alloy, nanostructured diopside (CaMgSi 2 O 6 ) has been coated on AZ91 Mg alloy using a combined micro arc oxidation (MAO) and electrophoretic deposition (EPD) method. The crystalline structure, the morphology and the composition of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electrochemical corrosion test, immersion test, and compression test were used to evaluate the corrosion resistance, the in vitro bioactivity and the mechanical stability of the samples, respectively. The cytocompatibility of the samples was tested by the cell viability and the cell attachment of L-929 cells. The results confirmed that the diopside coating not only slows down the corrosion rate, but also enhances the in vitro bioactivity, mechanical stability and cytocompatibility of AZ91 Mg alloy. Therefore, Mg alloy coated with nanostructured diopside offers a promising approach for biodegradable bone implants. - Highlights: • The diopside coating was applied on Mg alloy using the combined MAO and EPD methods. • The corrosion resistance of the diopside coated Mg alloy was noticeably improved. • The in vitro bioactivity of the diopside coated Mg alloy was considerably increased. • The mechanical stability of biodegradable Mg alloy was enhanced by diopside coating. • The cytocompatibility of the Mg alloy was improved employing diopside coating

  7. Slow Earthquake Hunters: A New Citizen Science Project to Identify and Catalog Slow Slip Events in Geodetic Data

    Science.gov (United States)

    Bartlow, N. M.

    2017-12-01

    Slow Earthquake Hunters is a new citizen science project to detect, catalog, and monitor slow slip events. Slow slip events, also called "slow earthquakes", occur when faults slip too slowly to generate significant seismic radiation. They typically take between a few days and over a year to occur, and are most often found on subduction zone plate interfaces. While not dangerous in and of themselves, recent evidence suggests that monitoring slow slip events is important for earthquake hazards, as slow slip events have been known to trigger damaging "regular" earthquakes. Slow slip events, because they do not radiate seismically, are detected with a variety of methods, most commonly continuous geodetic Global Positioning System (GPS) stations. There is now a wealth of GPS data in some regions that experience slow slip events, but a reliable automated method to detect them in GPS data remains elusive. This project aims to recruit human users to view GPS time series data, with some post-processing to highlight slow slip signals, and flag slow slip events for further analysis by the scientific team. Slow Earthquake Hunters will begin with data from the Cascadia subduction zone, where geodetically detectable slow slip events with a duration of at least a few days recur at regular intervals. The project will then expand to other areas with slow slip events or other transient geodetic signals, including other subduction zones, and areas with strike-slip faults. This project has not yet rolled out to the public, and is in a beta testing phase. This presentation will show results from an initial pilot group of student participants at the University of Missouri, and solicit feedback for the future of Slow Earthquake Hunters.

  8. In-situ thermal analysis and macroscopical characterization of Mg-xCa and Mg-0.5Ca-xZn alloy systems

    Energy Technology Data Exchange (ETDEWEB)

    Farahany, Saeed [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Bakhsheshi-Rad, Hamid Reza, E-mail: Rezabakhsheshi@gmail.com [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Idris, Mohd Hasbullah [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Abdul Kadir, Mohammed Rafiq [Medical Implants Technology Group, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Department of Biomechanics and Biomedical Materials, Faculty of Biomedical Engineering and Health Sciences, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Lotfabadi, Amir Fereidouni [Department of Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Ourdjini, Ali [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)

    2012-01-10

    Highlights: Black-Right-Pointing-Pointer The effect of Ca and Zn addition on Mg-Ca and Mg-Ca-Zn were investigated. Black-Right-Pointing-Pointer Ca and Zn addition decreased solid fraction at coherency point. Black-Right-Pointing-Pointer T{sub N}-T{sub DCP} increased by adding Ca and Zn in Mg-Ca and Mg-Ca-Zn, respectively. Black-Right-Pointing-Pointer Three reactions were detected when Zn/Ca atomic ratio less than 1.25 in Mg-Ca-Zn. Black-Right-Pointing-Pointer A new peak Mg{sub 51}Zn{sub 20} was identified in Mg-0.5Ca-9Zn in addition of other peaks. - Abstract: This research described the identification phases by thermal analysis and microscopy inspection of Mg-xCa and Mg-0.5%Ca-xZn alloys that were solidified at slow cooling rate. Analysis of cooling curve after Ca addition shows the evolution of the Mg{sub 2}Ca intermetallic phase at around 520 Degree-Sign C in addition to {alpha}-Mg phase. First derivative curves of alloys after the addition of Zn to Mg-0.5Ca alloy reveals three peaks related to {alpha}-Mg, Mg{sub 2}Ca and Ca{sub 2}Mg{sub 6}Zn{sub 3} for alloys that have Zn/Ca atomic ratio less than 1.23. The peak of Mg{sub 2}Ca reaction on the first derivative curves disappeared for alloys containing Zn/Ca ratio more than 1.23. A new peak was also observed at 330 Degree-Sign C for Mg-0.5Ca-9Zn which was identified as Mg{sub 51}Zn{sub 20}. Solid fraction at coherency point decreased with increasing Ca and Zn elements. However, coherency time and difference between the nucleation and coherency temperatures (T{sub N}-T{sub DCP}) increased by adding Ca and Zn in Mg-Ca and Mg-Ca-Zn systems.

  9. Construction report of the PF slow-positron source. 1

    International Nuclear Information System (INIS)

    Enomoto, Atsushi; Kurihara, Toshikazu; Kobayashi, Hitoshi

    1993-12-01

    The slow positron source utilizing the electron beam of the 2.5 GeV electron beam accelerator which is the synchrotron radiation injector is being constructed. The outline of the project and the present state of construction are reported. As of November, 1993, by injecting the electron beam of about 10 W to the targets for producing positrons, the slow positrons of 4 x 10 4 e + /s has been obtained in the laboratory. Finally, with the electron beam of 30 kW, it is aimed at to obtain the slow positron beam of 2 x 10 9 e + /s. In the slow positron source, the electron beam from the 2.5 GeV linear accelerator is used as the primary beam. This beam is led to the target with electromagnets. Radiation shields were strengthened, and the electrostatic lens system was attached to efficiently extract and send out slow positrons. The conveying system for slow positrons is explained. Primary electron beam, target and moderator for producing slow positrons, the change to continuous current of pulsed slow positron beam and the heightening of luminance of slow positron beam, and the experiment on the utilization of slow positron beam, and the control system for positron conveyance path are reported. (K.I.)

  10. In vitro conservation of Piper aduncum and Piper hispidinervum under slow-growth conditions

    Directory of Open Access Journals (Sweden)

    Tatiane Loureiro da Silva

    2011-04-01

    Full Text Available The objective of this work was to evaluate in vitro storage of Piper aduncum and P. hispidinervum under slow-growth conditions. Shoots were stored at low temperatures (10, 20 and 25°C, and the culture medium was supplemented with osmotic agents (sucrose and mannitol - at 1, 2 and 3% and abiscisic acid - ABA (0, 0.5, 1.0, 2.0 and 3.0 mg L-1. After six-months of storage, shoots were evaluated for survival and regrowth. Low temperature at 20ºC was effective for the in vitro conservation of P. aduncum and P. hispidinervum shoots. In vitro cultures maintained at 20ºC on MS medium showed 100% survival with slow-growth shoots. The presence of mannitol or ABA, in the culture medium, negatively affected shoot growth, which is evidenced by the low rate of recovered shoots.

  11. Slow positron beam study of corrosion behavior of AM60B magnesium alloy in NaCl solution

    International Nuclear Information System (INIS)

    Yang, W.; Zhu, Z.J.; Wang, J.J.; Wu, Y.C.; Zhai, T.; Song, G.-L.

    2016-01-01

    Highlights: • Positron annihilation is a sensitive tool to characterize the corrosion layer. • The interfacial voids promoted the formation of Mg(OH) 2 corrosion layer. • Mg(OH) 2 precipitated during early corrosion stage provided a temporary protection. - Abstract: The corrosion behavior of super vacuum die-cast AM60B magnesium alloys immersed in a 5 wt% NaCl solution was investigated by slow positron beam technique, XRD, XPS, SEM and potentiodynamic polarization tests. The XRD and XPS results indicated that Mg(OH) 2 was main corrosion product in the salt solution. With prolonging the immersion time, a significant decrease of Doppler-broadened annihilation line-width parameter near the surface after corrosion was observed and interpreted that the pre-existing interfacial voids between oxide film and matrix might promote the formation of Mg(OH) 2 corrosion layer. Polarization tests found that Mg(OH) 2 could provide a temporary protection.

  12. Toward standardization of slow earthquake catalog -Development of database website-

    Science.gov (United States)

    Kano, M.; Aso, N.; Annoura, S.; Arai, R.; Ito, Y.; Kamaya, N.; Maury, J.; Nakamura, M.; Nishimura, T.; Obana, K.; Sugioka, H.; Takagi, R.; Takahashi, T.; Takeo, A.; Yamashita, Y.; Matsuzawa, T.; Ide, S.; Obara, K.

    2017-12-01

    Slow earthquakes have now been widely discovered in the world based on the recent development of geodetic and seismic observations. Many researchers detect a wide frequency range of slow earthquakes including low frequency tremors, low frequency earthquakes, very low frequency earthquakes and slow slip events by using various methods. Catalogs of the detected slow earthquakes are open to us in different formats by each referring paper or through a website (e.g., Wech 2010; Idehara et al. 2014). However, we need to download catalogs from different sources, to deal with unformatted catalogs and to understand the characteristics of different catalogs, which may be somewhat complex especially for those who are not familiar with slow earthquakes. In order to standardize slow earthquake catalogs and to make such a complicated work easier, Scientific Research on Innovative Areas "Science of Slow Earthquakes" has been developing a slow earthquake catalog website. In the website, we can plot locations of various slow earthquakes via the Google Maps by compiling a variety of slow earthquake catalogs including slow slip events. This enables us to clearly visualize spatial relations among slow earthquakes at a glance and to compare the regional activities of slow earthquakes or the locations of different catalogs. In addition, we can download catalogs in the unified format and refer the information on each catalog on the single website. Such standardization will make it more convenient for users to utilize the previous achievements and to promote research on slow earthquakes, which eventually leads to collaborations with researchers in various fields and further understanding of the mechanisms, environmental conditions, and underlying physics of slow earthquakes. Furthermore, we expect that the website has a leading role in the international standardization of slow earthquake catalogs. We report the overview of the website and the progress of construction. Acknowledgment: This

  13. Slow positron applications at slow positron facility of institute of materials structure science, KEK

    Science.gov (United States)

    Hyodo, Toshio; Mochizuki, Izumi; Wada, Ken; Toge, Nobukazu; Shidara, Tetsuo

    2018-05-01

    Slow Positron Facility at High Energy Accelerator Research Organization (KEK) is a user dedicated facility with an energy-tunable (0.1 - 35 keV) slow positron beam created by a dedicated ˜ 50 MeV linac. It operates in a short pulse (width 1-12 ns, variable, 5×106 e+/s) and a long pulse (width 1.2 µs, 5×107 e+/s) modes of 50 Hz. High energy positrons from pair creation are moderated by reemission after thermalization in W foils. The reemitted positrons are then electrostatically accelerated to a desired energy up to 35 keV and magnetically transported. A pulse-stretching section (pulse stretcher) is installed in the middle of the beamline. It stretches the slow positron pulse for the experiments where too many positrons annihilating in the sample at the same time has to be avoided. Four experiment stations for TRHEPD (total-reflection high-energy positron diffraction), LEPD (low-energy positron diffraction), Ps- (positronium negative ion), and Ps-TOF (positronium time-of-flight) experiments are connected to the beamline branches, SPF-A3, SPF-A4, SPF-B1 and SPF-B2, respectively. Recent results of these stations are briefly described.

  14. Deciding about fast and slow decisions.

    Science.gov (United States)

    Croskerry, Pat; Petrie, David A; Reilly, James B; Tait, Gordon

    2014-02-01

    Two reports in this issue address the important topic of clinical decision making. Dual process theory has emerged as the dominant model for understanding the complex processes that underlie human decision making. This theory distinguishes between the reflexive, autonomous processes that characterize intuitive decision making and the deliberate reasoning of an analytical approach. In this commentary, the authors address the polarization of viewpoints that has developed around the relative merits of the two systems. Although intuitive processes are typically fast and analytical processes slow, speed alone does not distinguish them. In any event, the majority of decisions in clinical medicine are not dependent on very short response times. What does appear relevant to diagnostic ease and accuracy is the degree to which the symptoms of the disease being diagnosed are characteristic ones. There are also concerns around some methodological issues related to research design in this area of enquiry. Reductionist approaches that attempt to isolate dependent variables may create such artificial experimental conditions that both external and ecological validity are sacrificed. Clinical decision making is a complex process with many independent (and interdependent) variables that need to be separated out in a discrete fashion and then reflected on in real time to preserve the fidelity of clinical practice. With these caveats in mind, the authors believe that research in this area should promote a better understanding of clinical practice and teaching by focusing less on the deficiencies of intuitive and analytical systems and more on their adaptive strengths.

  15. Slow feature analysis: unsupervised learning of invariances.

    Science.gov (United States)

    Wiskott, Laurenz; Sejnowski, Terrence J

    2002-04-01

    Invariant features of temporally varying signals are useful for analysis and classification. Slow feature analysis (SFA) is a new method for learning invariant or slowly varying features from a vectorial input signal. It is based on a nonlinear expansion of the input signal and application of principal component analysis to this expanded signal and its time derivative. It is guaranteed to find the optimal solution within a family of functions directly and can learn to extract a large number of decorrelated features, which are ordered by their degree of invariance. SFA can be applied hierarchically to process high-dimensional input signals and extract complex features. SFA is applied first to complex cell tuning properties based on simple cell output, including disparity and motion. Then more complicated input-output functions are learned by repeated application of SFA. Finally, a hierarchical network of SFA modules is presented as a simple model of the visual system. The same unstructured network can learn translation, size, rotation, contrast, or, to a lesser degree, illumination invariance for one-dimensional objects, depending on only the training stimulus. Surprisingly, only a few training objects suffice to achieve good generalization to new objects. The generated representation is suitable for object recognition. Performance degrades if the network is trained to learn multiple invariances simultaneously.

  16. Range and stopping power for slow particles

    International Nuclear Information System (INIS)

    Bastiano, M.; Fernandez, J. E.; Molinari, V. G.

    1997-01-01

    Generally, the effects of thermal agitation and chemical bonding of the target atoms need to be taken into account to compute properly the range and stopping power of particles. These two effects, however, complicate very much the calculation of the above parameters, and for this reason are usually neglected. In fact, when the energy of the test particles (t.p.) is sufficiently high compared to the thermal or bonding energies, these two effects can be safely disregarded. When the energy of the t.p. is of the same order of the thermal agitation or the chemical bonding, on the other hand, such approximation is not realistic, and to obtain meaningful results one must take into account the velocity distribution of the field particles (f.p.). The aim of this paper is to present a simple model describing the transport of particles (e.g., electrons) in the thermal zone, considering the thermal agitation of f.p. with an arbitrary distribution. It will be shown that in the first part of the slowing down the kinetic energy of t.p. is partially transformed into temperature. In the second part, the temperature tends to reach the equilibrium temperature, while average velocity of t.p. becomes zero. (author)

  17. Mixing, ergodicity and slow relaxation phenomena

    Science.gov (United States)

    Costa, I. V. L.; Vainstein, M. H.; Lapas, L. C.; Batista, A. A.; Oliveira, F. A.

    2006-11-01

    Investigations on diffusion in systems with memory [I.V.L. Costa, R. Morgado, M.V.B.T. Lima, F.A. Oliveira, Europhys. Lett. 63 (2003) 173] have established a hierarchical connection between mixing, ergodicity, and the fluctuation-dissipation theorem (FDT). This hierarchy means that ergodicity is a necessary condition for the validity of the FDT, and mixing is a necessary condition for ergodicity. In this work, we compare those results with recent investigations using the Lee recurrence relations method [M.H. Lee, Phys. Rev. B 26 (1982) 2547; M.H. Lee, Phys. Rev. Lett. 87 (2001) 250601; M.H. Lee, J. Phys. A: Math. Gen. 39 (2006) 4651]. Lee shows that ergodicity is violated in the dynamics of the electron gas [M.H. Lee, J. Phys. A: Math. Gen. 39 (2006) 4651]. This reinforces both works and implies that the results of [I.V.L. Costa, R. Morgado, M.V.B.T. Lima, F.A. Oliveira, Europhys. Lett. 63 (2003) 173] are more general than the framework in which they were obtained. Some applications to slow relaxation phenomena are discussed.

  18. Commodity chemical growth to slow in 1993

    International Nuclear Information System (INIS)

    Plishner, E.S.

    1992-01-01

    In their latest chemical outlook, DRI/McGraw-Hill economists characterize 1992 as a peak year for U.S. commodity chemical demand growth, at 4.2%, tapering off to a compound 2.2% between 1993 and 1995. Just as operating rates begin to reach higher levels in 1995, however, DRI forecasts slowing GNP growth. DRI's Ramunas J. Svarcas expects a decline in exports. Those plastics promising the rosiest consumption outlook include melamine-formaldehyde resin, up 9.9% in 1992, from 155 million lbs in 1991, and projected to grow 8.6%/year through 1995; styrene acrylonitrile resin, up 23% this year, from 58 million lbs last year, and growing 8.2%/year through 1995; and unsaturated polyester, up 11.7% this year, from 1.07 billion lbs in 1991, and increasing at 6.5%/year. Methanol is a bright spot, with consumption growing 4.7%, from 11.2 billion lbs in 1991 and 12%/year thereafter. Ortho-xylene managed an impressive 21% rebound from a depressed 1991 level of 783 million lbs, and is expected to continue its recovery at 7.7%/year

  19. Molten fuel behaviour during slow overpower transients

    International Nuclear Information System (INIS)

    Guerin, Y.; Boidron, M.

    1985-01-01

    In large commercial reactors as Super-Phenix, if we take into account all the uncertainties on the pins and on the core, it is no longer possible to guarantee the absence of fuel melting during incidental events such as slow overpower transients. We have then to explain what happens in the pins when fuel melting occurs and to demonstrate that a limited amount of molten fuel generates no risk of clad failure. For that purpose, we may use the results of a great number of experiments (about 40) that have been performed at C.E.A., most of them in thermal reactor, but some experiments have also been performed in Rapsodie, especially during the last run of this reactor. In a great part of these experiments, fuel melting occurred at beginning of life, but we have also some results at different burnups up to 5 at %. It is not the aim of this paper to describe all these experiments and the results of their post irradiation examination, but to summarize the main conclusions that have been set out of them and that have enabled us to determine the main characteristics of fuel element behaviour when fuel melting occurs

  20. Origin of Pseudotachylites during slow creep experiments

    Science.gov (United States)

    Peč, M.; Stünitz, H.; Heilbronner, R.; Drury, M.; De Capitani, C.

    2012-04-01

    Pseudotachylites are interpreted as solidified friction induced melts which form exclusively during seismic or impact events and are thus accepted as 'unequivocal evidence' of paleo-earthquakes on exhumed faults. However, we found in experiments that pseudotachylites can form under clearly aseismic conditions at confining pressures and temperatures typical of mid crustal levels (Pc = 500 MPa, T = 300° C). The starting material consists of granitoid powder crushed to a size of ≤ 200 μm in diameter. This material (0.1 g), with 0.2 wt% water added, is placed between alumina forcing blocks pre-cut at 45° , weld-sealed in platinum jackets with an inner nickel foil insert and deformed in a solid medium deformation apparatus (modified Griggs rig). We applied displacement rates of (10-8 ms-1 precursor material and is in general more ferromagnesian and basic compared to the bulk rock indicating preferred melting of biotite. The calculated temperature increase due to shear heating is at the most 5°C. High stresses cause pervasive comminution: the smallest crystalline fragments within the bubbly melt have a grain diameter of 10 nm. Nanomaterials exhibit a 'melting point depression' (dependence of melting point on grain size) which allows melting well below bulk melting temperatures. Thus, it seems that melting is a continuation of the comminution once the rock has reached small enough grain size. We therefore suggest that pseudotachylites may also form as 'mechanical melts' at slow displacement rates without the necessity of reaching high temperatures.

  1. Task-dependent inhibition of slow-twitch soleus and excitation of fast-twitch gastrocnemius do not require high movement speed and velocity-dependent sensory feedback

    Directory of Open Access Journals (Sweden)

    Ricky eMehta

    2014-10-01

    Full Text Available Although individual heads of triceps surae, soleus (SO and medial gastrocnemius (MG muscles, are often considered close functional synergists, previous studies have shown distinct activity patterns between them in some motor behaviors. The goal of this study was to test two hypotheses explaining inhibition of slow SO with respect to fast MG: (1 inhibition occurs at high movement velocities and mediated by velocity-dependent sensory feedback and (2 inhibition depends on the ankle-knee joint moment combination and does not require high movement velocities. The hypotheses were tested by comparing the SO EMG/MG EMG ratio during fast and slow motor behaviors (cat paw shake responses vs. back, straight leg load lifting in humans, which had the same ankle extension-knee flexion moment combination; and during fast and slow behaviors with the ankle extension-knee extension moment combination (human vertical jumping and stance phase of walking in cats and leg load lifting in humans. In addition, SO EMG/MG EMG ratio was determined during cat paw shake responses and walking before and after removal of stretch velocity-dependent sensory feedback by self-reinnervating SO and/or gastrocnemius. We found the ratio SO EMG/MG EMG below 1 (p<0.05 during fast paw shake responses and slow back load lifting, requiring the ankle extension-knee flexion moment combination; whereas the ratio SO EMG/MG EMG was above 1 (p<0.05 during fast vertical jumping and slow tasks of walking and leg load lifting, requiring ankle extension-knee extension moments. Removal of velocity-dependent sensory feedback did not affect the SO EMG/MG EMG ratio in cats. We concluded that the relative inhibition of SO does not require high muscle velocities, depends on ankle-knee moment combinations, and is mechanically advantageous for allowing a greater MG contribution to ankle extension and knee flexion moments.

  2. A comparison of amorphous calcium carbonate crystallization in aqueous solutions of MgCl2 and MgSO4: implications for paleo-ocean chemistry

    Science.gov (United States)

    Han, Mei; Zhao, Yanyang; Zhao, Hui; Han, Zuozhen; Yan, Huaxiao; Sun, Bin; Meng, Ruirui; Zhuang, Dingxiang; Li, Dan; Liu, Binwei

    2018-04-01

    Based on the terminology of "aragonite seas" and "calcite seas", whether different Mg sources could affect the mineralogy of carbonate sediments at the same Mg/Ca ratio was explored, which was expected to provide a qualitative assessment of the chemistry of the paleo-ocean. In this work, amorphous calcium carbonate (ACC) was prepared by direct precipitation in anhydrous ethanol and used as a precursor to study crystallization processes in MgSO4 and MgCl2 solutions having different concentrations at 60 °C (reaction times 240 and 2880 min). Based on the morphology of the aragonite crystals, as well as mineral saturation indices and kinetic analysis of geochemical processes, it was found that these crystals formed with a spherulitic texture in 4 steps. First, ACC crystallized into columnar Mg calcite by nearly oriented attachment. Second, the Mg calcite changed from columnar shapes into smooth dumbbell forms. Third, the Mg calcite transformed into rough dumbbell or cauliflower-shaped aragonite forms by local dissolution and precipitation. Finally, the aragonite transformed further into spherulitic radial and irregular aggregate forms. The increase in Ca2+ in the MgSO4 solutions compared with the MgCl2 solutions indicates the fast dissolution and slow precipitation of ACC in the former solutions. The phase transition was more complete in the 0.005 M MgCl2 solution, whereas Mg calcite crystallized from the 0.005 M MgSO4 solution, indicating that Mg calcite could be formed more easily in an MgSO4 solution. Based on these findings, aragonite and Mg calcite relative to ACC could be used to provide a qualitative assessment of the chemistry of the paleo-ocean. Therefore, calcite seas relative to high-Mg calcite could reflect a low concentration MgSO4 paleo-ocean, while aragonite seas could be related to an MgCl2 or high concentration of MgSO4 paleo-ocean.

  3. In vitro degradation and cytotoxicity of Mg/Ca composites produced by powder metallurgy.

    Science.gov (United States)

    Zheng, Y F; Gu, X N; Xi, Y L; Chai, D L

    2010-05-01

    Mg/Ca (1 wt.%, 5 wt.%, 10 wt.% Ca) composites were prepared from pure magnesium and calcium powders using the powder metallurgy method, aiming to enlarge the addition of Ca content without the formation of Mg(2)Ca. The microstructures, mechanical properties and cytotoxicities of Mg/Ca composite samples were investigated. The corrosion of Mg/Ca composites in Dulbecco's modified Eagle's medium (DMEM) for various immersion intervals was studied by electrochemical impedance spectroscopy measurements and environmental scanning electron microscope, with the concentrations of released Mg and Ca ions in DMEM for various immersion time intervals being measured. It was shown that the main constitutional phases were Mg and Ca, which were uniformly distributed in the Mg matrix. The ultimate tensile strength (UTS) and elongation of experimental composites decreased with increasing Ca content, and the UTS of Mg/1Ca composite was comparable with that of as-extruded Mg-1Ca alloy. The corrosion potential increased with increasing Ca content, whereas the current density and the impedance decreased. It was found that the protective surface film formed quickly at the initial immersion stage. With increasing immersion time, the surface film became compact, and the corrosion rate of Mg/Ca composites slowed down. The surface film consisted mainly of CaCO(3), MgCO(3)x3H(2)O, HA and Mg(OH)(2) after 72 h immersion in DMEM. Mg/1Ca and Mg/5Ca composite extracts had no significant toxicity (p>0.05) to L-929 cells, whereas Mg/10Ca composite extract induced approximately 40% reduced cell viability. Copyright (c) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. A new slow positron beam facility using a compact cyclotron

    International Nuclear Information System (INIS)

    Hirose, Masafumi

    1998-01-01

    In 1993, Sumitomo Heavy Industries became the first in the world to successfully produce a slow positron beam using a compact cyclotron. Slow positron beam production using an accelerator had mainly consisted of using an electron linear accelerator (LINAC). However, the newly developed system that uses a compact cyclotron enabled cost reduction, downsizing of equipment, production of a DC slow positron beam, a polarized slow positron beam, and other benefits. After that, a genuine slow positron beam facility was developed with the construction of compact cyclotron No.2, and beam production in the new facility has already been started. The features of this new slow positron beam facility are explained below. 1) It is the world's first compact slow positron beam facility using a compact cyclotron. 2) It is the only genuine slow positron beam facility in the world which incorporates the production and use of a slow positron beam in the design stage of the cyclotron. To use a slow positron beam for non-destructive detection of lattice defects in semiconductor material, it is necessary to convert the beam into ultra-short pulses of several hundreds of pico-seconds. Sumitomo Heavy Industries has devised a new short-pulsing method (i.e. an induction bunching method) that enables the conversion of a slow positron beam into short pulses with an optimum pulsing electric field change, and succeeded in converting a slow positron beam into short pulses using this method for the first time in the world. Non-destructive detection of lattice defects in semiconductor material using this equipment has already been started, and some information about the depth distribution, size, density, etc. of lattice defects has already been obtained. (J.P.N.)

  5. Fast wave current drive above the slow wave density limit

    International Nuclear Information System (INIS)

    McWilliams, R.; Sheehan, D.P.; Wolf, N.S.; Edrich, D.

    1989-01-01

    Fast wave and slow wave current drive near the mean gyrofrequency were compared in the Irvine Torus using distinct phased array antennae of similar principal wavelengths, frequencies, and input powers. The slow wave current drive density limit was measured for 50ω ci ≤ω≤500ω ci and found to agree with trends in tokamaks. Fast wave current drive was observed at densities up to the operating limit of the torus, demonstrably above the slow wave density limit

  6. PRINCIPLES OF SLOW TRAVEL APPLIED TO TOURIST LEISURE CONTEMPORARY

    OpenAIRE

    Bauer, Rafael Chequer; Netto, Alexandre Panosso

    2014-01-01

    The article shows the concept of Slow Travel, a travel’s modality based in a new perspective of touristic use considering a slowdown style. In this way, the paper analyses the context of growing and development about Slow Travel, including its ideological matrix based in industrial revolution’s contestation, specially about the acceleration noted at contemporary society and its application inside the leisure and travel universes. At least, shows the main characteristics of Slow Travel, and it...

  7. Increased mental slowing associated with the APOE epsilon4 allele after trihexyphenidyl oral anticholinergic challenge in healthy elderly.

    Science.gov (United States)

    Pomara, Nunzio; Belzer, Ken; Hernando, Raymundo; De La Pena, Corazon; Sidtis, John J

    2008-02-01

    The objectives of this study were to examine the relationship between APOE epsilon4 and subjective effects of trihexyphenidyl on measures reflecting sedation and confusion and to investigate the relationship between trihexyphenidyl-induced subjective effects and objective memory performance. This study comprised 24 cognitively intact, health elderly adults (12 APOE epsilon4 carriers) at an outpatient geriatric psychiatry research clinic. This was a randomized, double blind, placebo-controlled, three-way, crossover experimental design. All participants received 1.0 mg or 2.0 mg trihexyphenidyl or placebo administered in counterbalanced sequences over a period of three consecutive weeks. Bond and Lader's visual analog scales and alternate versions of the Buschke Selective Reminding Test were administered in a repeated measures design at baseline, 1, 2.5, and 5 hours postdrug administration. A 2.0-mg oral dose of trihexyphenidyl resulted in increased subjective ratings of mental slowness in carriers of the APOE epsilon4 allele only. Drug effects as determined by difference scores between 2.0 mg trihexyphenidyl and placebo on ratings of mental slowness significantly correlated with total and delayed recall on the Buschke Selective Reminding Test in carriers of the APOE epsilon4 allele only. However, no significant effects were found with other visual analog scales reflecting subjective sedation and clear-headedness. The epsilon4 allele in healthy elderly was associated with increased subjective mental slowing after trihexyphenidyl anticholinergic challenge.

  8. Threshold Characteristics of Slow-Light Photonic Crystal Lasers

    DEFF Research Database (Denmark)

    Xue, Weiqi; Yu, Yi; Ottaviano, Luisa

    2016-01-01

    The threshold properties of photonic crystal quantum dot lasers operating in the slow-light regime are investigated experimentally and theoretically. Measurements show that, in contrast to conventional lasers, the threshold gain attains a minimum value for a specific cavity length. The experimental...... results are explained by an analytical theory for the laser threshold that takes into account the effects of slow light and random disorder due to unavoidable fabrication imperfections. Longer lasers are found to operate deeper into the slow-light region, leading to a trade-off between slow-light induced...

  9. Application of Planar Broadband Slow-Wave Systems

    Directory of Open Access Journals (Sweden)

    Edvardas Metlevskis

    2012-04-01

    Full Text Available Different types of planar broadband slow-wave systems are used for designing microwave devices. The papers published by Lithuanian scientists analyze and investigate the models of helical and meander slow-wave systems. The article carefully examines the applications of meander slow-wave systems and presents the areas where similar systems, e.g. mobile devices, RFID, wireless technologies are used and reviewed nowadays. The paper also focuses on the examples of the papers discussing antennas, filters and couplers that contain designed and fabricated meander slow-wave systems.Article in Lithuanian

  10. Thermodynamic Tuning of Mg-Based Hydrogen Storage Alloys: A Review

    Science.gov (United States)

    Zhu, Min; Lu, Yanshan; Ouyang, Liuzhang; Wang, Hui

    2013-01-01

    Mg-based hydrides are one of the most promising hydrogen storage materials because of their relatively high storage capacity, abundance, and low cost. However, slow kinetics and stable thermodynamics hinder their practical application. In contrast to the substantial progress in the enhancement of the hydrogenation/dehydrogenation kinetics, thermodynamic tuning is still a great challenge for Mg-based alloys. At present, the main strategies to alter the thermodynamics of Mg/MgH2 are alloying, nanostructuring, and changing the reaction pathway. Using these approaches, thermodynamic tuning has been achieved to some extent, but it is still far from that required for practical application. In this article, we summarize the advantages and disadvantages of these strategies. Based on the current progress, finding reversible systems with high hydrogen capacity and effectively tailored reaction enthalpy offers a promising route for tuning the thermodynamics of Mg-based hydrogen storage alloys. PMID:28788353

  11. Use of drug therapy in the management of symptomatic ureteric stones in hospitalized adults (SUSPEND), a multicentre, placebo-controlled, randomized trial of a calcium-channel blocker (nifedipine) and an α-blocker (tamsulosin): study protocol for a randomized controlled trial

    Science.gov (United States)

    2014-01-01

    Background Urinary stone disease is common, with an estimated prevalence among the general population of 2% to 3%. Ureteric stones can cause severe pain and have a significant impact on quality of life, accounting for over 15,000 hospital admissions in England annually. Uncomplicated cases of smaller stones in the lower ureter are traditionally treated expectantly. Those who fail standard care or develop complications undergo active treatment, such as extracorporeal shock wave lithotripsy or ureteroscopy with stone retrieval. Such interventions are expensive, require urological expertise and carry a risk of complications. Growing understanding of ureteric function and pathophysiology has led to the hypothesis that drugs causing relaxation of ureteric smooth muscle, such as the selective α-blocker tamsulosin and the calcium-channel blocker nifedipine, can enhance the spontaneous passage of ureteric stones. The use of drugs in augmenting stone passage, reducing the morbidity and costs associated with ureteric stone disease, is promising. However, the majority of clinical trials conducted to date have been small, poor to moderate quality and lacking in comprehensive economic evaluation. This trial aims to determine the clinical and cost-effectiveness of tamsulosin and nifedipine in the management of symptomatic urinary stones. Methods/design The SUSPEND (Spontaneous Urinary Stone Passage ENabled by Drugs) trial is a multicentre, double-blind, randomized controlled trial evaluating two medical expulsive therapy strategies (nifedipine or tamsulosin) versus placebo. Patients aged 18 to 65 with a ureteric stone confirmed by non-contrast computed tomography of the kidney, ureter and bladder will be randomized to receive nifedipine, tamsulosin or placebo (400 participants per arm) for a maximum of 28 days. The primary clinical outcome is spontaneous passage of ureteric stones at 4 weeks (defined as no further intervention required to facilitate stone passage). The

  12. Use of drug therapy in the management of symptomatic ureteric stones in hospitalized adults (SUSPEND), a multicentre, placebo-controlled, randomized trial of a calcium-channel blocker (nifedipine) and an α-blocker (tamsulosin): study protocol for a randomized controlled trial.

    Science.gov (United States)

    McClinton, Sam; Starr, Kathryn; Thomas, Ruth; McLennan, Graeme; McPherson, Gladys; McDonald, Alison; Lam, Thomas; N'Dow, James; Kilonzo, Mary; Pickard, Robert; Anson, Ken; Burr, Jennifer

    2014-06-20

    Urinary stone disease is common, with an estimated prevalence among the general population of 2% to 3%. Ureteric stones can cause severe pain and have a significant impact on quality of life, accounting for over 15,000 hospital admissions in England annually. Uncomplicated cases of smaller stones in the lower ureter are traditionally treated expectantly. Those who fail standard care or develop complications undergo active treatment, such as extracorporeal shock wave lithotripsy or ureteroscopy with stone retrieval. Such interventions are expensive, require urological expertise and carry a risk of complications.Growing understanding of ureteric function and pathophysiology has led to the hypothesis that drugs causing relaxation of ureteric smooth muscle, such as the selective α-blocker tamsulosin and the calcium-channel blocker nifedipine, can enhance the spontaneous passage of ureteric stones. The use of drugs in augmenting stone passage, reducing the morbidity and costs associated with ureteric stone disease, is promising. However, the majority of clinical trials conducted to date have been small, poor to moderate quality and lacking in comprehensive economic evaluation.This trial aims to determine the clinical and cost-effectiveness of tamsulosin and nifedipine in the management of symptomatic urinary stones. The SUSPEND (Spontaneous Urinary Stone Passage ENabled by Drugs) trial is a multicentre, double-blind, randomized controlled trial evaluating two medical expulsive therapy strategies (nifedipine or tamsulosin) versus placebo.Patients aged 18 to 65 with a ureteric stone confirmed by non-contrast computed tomography of the kidney, ureter and bladder will be randomized to receive nifedipine, tamsulosin or placebo (400 participants per arm) for a maximum of 28 days. The primary clinical outcome is spontaneous passage of ureteric stones at 4 weeks (defined as no further intervention required to facilitate stone passage). The primary economic outcome is a

  13. Anorexia nervosa: slow regain of bone mass.

    Science.gov (United States)

    Valla, A; Groenning, I L; Syversen, U; Hoeiseth, A

    2000-01-01

    In a retrospective study of women aged 18-30 years, aimed at assessing factors associated with peak bone mass (PBM), 13 of 239 study cases reported having had anorexia nervosa. The mean total femoral and lumbar bone mineral density (BMD) values were not significantly lower in women who had had anorexia than in the pooled group (mean Z-scores of -0.60 and -0.48). Cases with less than 6 years since the anorexia had on average a present weight 5.7 kg less than their premorbid weights, while cases with more than 6 years since the eating disorder had an average weight 22.5 kg above their pre-morbid weights. The cases who had not regained their weight had BMD values significantly lower than the pooled material (mean Z-scores -1.15 and -0.9 in the lumbar spine and total femur respectively). Those who had regained their weight had BMD values as predicted from their present anthropometric data, while those who had not regained their weight had BMD values that were substantially below that predicted from their present weight. Anorexia nervosa seems to be associated with a low BMD which is even lower than that which can be predicted from the weight loss alone. This suggests that weight loss and other factors, such as menstrual dysfunction and estrogen deficiency, are independent and thus additive causes of bone loss in anorexia nervosa. Recovery of BMD seems slow, but the BMD may become as predicted from the anthropometric data after restoration of body weight and menses. The potential for recovery of BMD seems intact for several years after menarche.

  14. Post-Mesozoic Rapid Increase of Seawater Mg/Ca due to Enhanced Mantle-Seawater Interaction

    OpenAIRE

    Marco Ligi; Enrico Bonatti; Marco Cuffaro; Daniele Brunelli

    2013-01-01

    The seawater Mg/Ca ratio increased significantly from ~ 80?Ma to present, as suggested by studies of carbonate veins in oceanic basalts and of fluid inclusions in halite. We show here that reactions of mantle-derived peridotites with seawater along slow spreading mid-ocean ridges contributed to the post-Cretaceous Mg/Ca increase. These reactions can release to modern seawater up to 20% of the yearly Mg river input. However, no significant peridotite-seawater interaction and Mg-release to the ...

  15. Preparation and Hydrogen Storage Properties of Mg-Rich Mg-Ni Ultrafine Particles

    Directory of Open Access Journals (Sweden)

    Jianxin Zou

    2012-01-01

    Full Text Available In the present work, Mg-rich Mg-Ni ultrafine powders were prepared through an arc plasma method. The phase components, microstructure, and hydrogen storage properties of the powders were carefully investigated. It is found that Mg2Ni and MgNi2 could be obtained directly from the vapor state reactions between Mg and Ni, depending on the local vapor content in the reaction chamber. A nanostructured MgH2 + Mg2NiH4 hydrogen storage composite could be generated after hydrogenation of the Mg-Ni ultrafine powders. After dehydrogenation, MgH2 and Mg2NiH4 decomposed into nanograined Mg and Mg2Ni, respectively. Thermogravimetry/differential scanning calorimetry (TG/DSC analyses showed that Mg2NiH4 phase may play a catalytic role in the dehydriding process of the hydrogenated Mg ultrafine particles.

  16. Experimental determination of the slow-neutron wavelength distribution

    DEFF Research Database (Denmark)

    Lebech, Bente; Mikke, K.; Sledziewska-Blocka, D.

    1970-01-01

    Different experiments for determining the slow-neutron wavelength distribution in the region 227-3 meV have been carried out, and the results compared. It is concluded that the slow-neutron wave-length distribution can be determined accurately by elastic scattering on a pure incoherent or a pure...

  17. The Localizing Value Of Focal Delta Slowing In Temporal Lobe ...

    African Journals Online (AJOL)

    Slow wave EEG had a higher marginal probability than neuropsychological assessment of predicting the focus, and was equally effective as other investigative methods. Conclusion These results suggest that focal temporal delta slowing is useful in the localization of epileptogenic foci. There was no discordance with the ...

  18. On the reasons for bombarding uranium with slow neutrons

    International Nuclear Information System (INIS)

    Xu Diyu

    1997-01-01

    Form the concepts of slow neutrons, the binding energy and the excitation energy of complex nuclei, and the activation energy in nuclear fission, the four reasons for bombarding uranium with slow neutrons are summed up. Not only the reasons for uranium fission are brought in light, but also the micromechanism is dealt with

  19. Slow Light at High Frequencies in an Amplifying Semiconductor Waveguide

    DEFF Research Database (Denmark)

    Öhman, Filip; Yvind, Kresten; Mørk, Jesper

    2006-01-01

    We demonstrate slow-down of a modulated light signal in a semiconductor waveguide. Concatenated amplifying and absorbing sections simultaneously achieve both amplification and a controllable time delay at 15 GHz.......We demonstrate slow-down of a modulated light signal in a semiconductor waveguide. Concatenated amplifying and absorbing sections simultaneously achieve both amplification and a controllable time delay at 15 GHz....

  20. Spacetime Dynamics and Slow Neutrino Background

    Science.gov (United States)

    Zhang, Tianxi

    2018-06-01

    Space is a form of existence of matter, while time is a measure of change of the matter in the space. Issac Newton suggested that the space and time are absolute, not affected by matter and its motion. His first law of motion or the law of inertia says that, without net force acts on it, an object in motion remains the motion in a straight line at a constant speed. Ernest Mach proposed that the inertia of a body results from the gravitational interaction on the body by the rest of the entire universe. As mass is a measure of inertia, Mach’s principle can be simply stated as mass here is affected by matter there. On the basis of Mach’s principle, Albert Einstein considered the space and time to be relative and developed two theories of relativities. One called special relativity describes the effect of motion on spacetime and the other called general relativity describes the effect of matter on spacetime. Recently, the author has further considered reactions of the influenced spacetime on the moving objects, including photons. A moving object including a photon, because of its continuously keeping on displacement, disturbs the rest of the entire universe or distorts/curves the spacetime. The distorted or curved spacetime then generates an effective gravitational force to act back on the moving object or photon, so that reduces the object inertia or photon frequency. Considering the disturbance of spacetime by a photon is extremely weak, the author has modelled the effective gravitational force to be Newtonian and derived a new redshift-distance relation that not only perfectly explained the redshift-distance measurement of distant type Ia supernovae but also inherently obtained Hubble’s law as an approximate at small redshift. In this study, we will further analyse the reaction of the influenced spacetime on moving neutrinos and demonstrate the creation of slow neutrino (or tired neutrino) background that may be gravitationally orbiting around clusters

  1. On Kinetic Slow Modes, Fluid Slow Modes, and Pressure-balanced Structures in the Solar Wind

    Energy Technology Data Exchange (ETDEWEB)

    Verscharen, Daniel [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Chen, Christopher H. K. [Department of Physics, Imperial College London, London SW7 2AZ (United Kingdom); Wicks, Robert T., E-mail: daniel.verscharen@unh.edu, E-mail: christopher.chen@imperial.ac.uk, E-mail: r.wicks@ucl.ac.uk [Mullard Space Science Laboratory, University College London, London WC1E 6BT (United Kingdom)

    2017-05-10

    Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for nonthermal features to survive, which suggests the requirement of a kinetic plasma description. The least-damped kinetic slow mode is associated with the ion-acoustic (IA) wave and a nonpropagating (NP) mode. We derive analytical expressions for the IA-wave dispersion relation in an anisotropic plasma in the framework of gyrokinetics and then compare them to fully kinetic numerical calculations, results from two-fluid theory, and magnetohydrodynamics (MHD). This comparison shows major discrepancies in the predicted wave phase speeds from MHD and kinetic theory at moderate to high β . MHD and kinetic theory also dictate that all plasma normal modes exhibit a unique signature in terms of their polarization. We quantify the relative amplitude of fluctuations in the three lowest particle velocity moments associated with IA and NP modes in the gyrokinetic limit and compare these predictions with MHD results and in situ observations of the solar-wind turbulence. The agreement between the observations of the wave polarization and our MHD predictions is better than the kinetic predictions, which suggests that the plasma behaves more like a fluid in the solar wind than expected.

  2. Slow Money for Soft Energy: Lessons for Energy Finance from the Slow Money Movement

    Energy Technology Data Exchange (ETDEWEB)

    Kock, Beaudry E. [Environmental Change Institute, University of Oxford, Oxford (United Kingdom)], e-mail: beaudry.kock@ouce.ox.ac.uk

    2012-12-15

    Energy infrastructure is decarbonizing, shifting from dirty coal to cleaner gas- and emissions-free renewables. This is an important and necessary change that unfortunately risks preserving many problematic technical and institutional properties of the old energy system: in particular, the large scales, high aggregation, and excessive centralization of renewable energy infrastructure and, importantly, its financing. Large-scale renewables carry environmental, social and political risks that cannot be ignored, and more importantly they may not alone accomplish the necessary decarbonization of the power sector. We need to revive a different approach to clean energy infrastructure: a 'softer' (Lovins 1978), more distributed, decentralized, local-scale strategy. To achieve this, we need a fundamentally different approach to the financing of clean energy infrastructure. I propose we learn from the 'Slow Money' approach being pioneered in sustainable agriculture (Tasch 2010), emphasizing a better connection to place, smaller scales, and a focus on quality over quantity. This 'slow money, soft energy' vision is not a repudiation of big-scale renewables, since there are some societal needs, which can only be met by big, centralized power. But we do not need the level of concentration in control and finance epitomized by the current trends in the global renewables sector: this can and must change.

  3. On Kinetic Slow Modes, Fluid Slow Modes, and Pressure-balanced Structures in the Solar Wind

    International Nuclear Information System (INIS)

    Verscharen, Daniel; Chen, Christopher H. K.; Wicks, Robert T.

    2017-01-01

    Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for nonthermal features to survive, which suggests the requirement of a kinetic plasma description. The least-damped kinetic slow mode is associated with the ion-acoustic (IA) wave and a nonpropagating (NP) mode. We derive analytical expressions for the IA-wave dispersion relation in an anisotropic plasma in the framework of gyrokinetics and then compare them to fully kinetic numerical calculations, results from two-fluid theory, and magnetohydrodynamics (MHD). This comparison shows major discrepancies in the predicted wave phase speeds from MHD and kinetic theory at moderate to high β . MHD and kinetic theory also dictate that all plasma normal modes exhibit a unique signature in terms of their polarization. We quantify the relative amplitude of fluctuations in the three lowest particle velocity moments associated with IA and NP modes in the gyrokinetic limit and compare these predictions with MHD results and in situ observations of the solar-wind turbulence. The agreement between the observations of the wave polarization and our MHD predictions is better than the kinetic predictions, which suggests that the plasma behaves more like a fluid in the solar wind than expected.

  4. Enhancement of sleep slow waves: underlying mechanisms and practical consequences.

    Directory of Open Access Journals (Sweden)

    Michele eBellesi

    2014-10-01

    Full Text Available Even modest sleep restriction, especially the loss of sleep slow wave activity, is invariably associated with slower EEG activity during wake, the occurrence of local sleep in an otherwise awake brain, and impaired performance due to cognitive and memory deficits. Recent studies not only confirm the beneficial role of sleep in memory consolidation, but also point to a specific role for sleep slow waves. Thus, the implementation of methods to enhance sleep slow waves without unwanted arousals or lightening of sleep could have significant practical implications. Here we first review the evidence that it is possible to enhance sleep slow waves in humans using transcranial direct-current stimulation and transcranial magnetic stimulation. Since these methods are currently impractical and their safety is questionable, especially for chronic long-term exposure, we then discuss novel data suggesting that it is possible to enhance slow waves using sensory stimuli. We consider the physiology of the K-complex, a peripheral evoked slow wave, and show that, among different sensory modalities, acoustic stimulation is the most effective in increasing the magnitude of slow waves, likely through the activation of non-lemniscal ascending pathways to the thalamo-cortical system. In addition, we discuss how intensity and frequency of the acoustic stimuli, as well as exact timing and pattern of stimulation, affect sleep enhancement. Finally, we discuss automated algorithms that read the EEG and, in real-time, adjust the stimulation parameters in a closed-loop manner to obtain an increase in sleep slow waves and avoid undesirable arousals. In conclusion, while discussing the mechanisms that underlie the generation of sleep slow waves, we review the converging evidence showing that acoustic stimulation is safe and represents an ideal tool for slow wave sleep enhancement.

  5. Impact of interface manipulation of oxide on electrical transport properties and low-frequency noise in MgO/NiFe/MgO heterojunctions

    International Nuclear Information System (INIS)

    Li, Jian-wei; Zhao, Chong-jun; Feng, Chun; Yu, Guang-hua; Zhou, Zhongfu

    2015-01-01

    Low-frequency noise and magnetoresistance in sputtered-deposited Ta(5 nm)/MgO (3 nm)/NiFe(10 nm)/MgO(3 nm)/Ta(3 nm) films have been measured as a function of different annealing times at 400°C. These measurements did not change synchronously with annealing time. A significant increase in magnetoresistance is observed for short annealing times (of the order of minutes) and is correlated with a relatively small reduction in 1/f noise. In contrast, a significant reduction in 1/f noise is observed for long annealing times (of the order of hours) accompanied by a small change in magnetoresistance. After annealing for 2 hours, the 1/f noise decreases by three orders of magnitude. Transmission electron microscopy and slow positron annihilation results implicate the cause being micro-structural changes in the MgO layers and interfaces following different annealing times. The internal vacancies in the MgO layers gather into vacancy clusters to reduce the defect density after short annealing times, whereas the MgO/NiFe and the NiFe/MgO interfaces improve significantly after long annealing times with the amorphous MgO layers gradually crystallizing following the release of interfacial stress

  6. Impact of interface manipulation of oxide on electrical transport properties and low-frequency noise in MgO/NiFe/MgO heterojunctions

    Science.gov (United States)

    Li, Jian-wei; Zhao, Chong-jun; Feng, Chun; Zhou, Zhongfu; Yu, Guang-hua

    2015-08-01

    Low-frequency noise and magnetoresistance in sputtered-deposited Ta(5 nm)/MgO (3 nm)/NiFe(10 nm)/MgO(3 nm)/Ta(3 nm) films have been measured as a function of different annealing times at 400°C. These measurements did not change synchronously with annealing time. A significant increase in magnetoresistance is observed for short annealing times (of the order of minutes) and is correlated with a relatively small reduction in 1/f noise. In contrast, a significant reduction in 1/f noise is observed for long annealing times (of the order of hours) accompanied by a small change in magnetoresistance. After annealing for 2 hours, the 1/f noise decreases by three orders of magnitude. Transmission electron microscopy and slow positron annihilation results implicate the cause being micro-structural changes in the MgO layers and interfaces following different annealing times. The internal vacancies in the MgO layers gather into vacancy clusters to reduce the defect density after short annealing times, whereas the MgO/NiFe and the NiFe/MgO interfaces improve significantly after long annealing times with the amorphous MgO layers gradually crystallizing following the release of interfacial stress.

  7. Impact of interface manipulation of oxide on electrical transport properties and low-frequency noise in MgO/NiFe/MgO heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian-wei [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhao, Chong-jun; Feng, Chun; Yu, Guang-hua [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhou, Zhongfu [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)

    2015-08-15

    Low-frequency noise and magnetoresistance in sputtered-deposited Ta(5 nm)/MgO (3 nm)/NiFe(10 nm)/MgO(3 nm)/Ta(3 nm) films have been measured as a function of different annealing times at 400°C. These measurements did not change synchronously with annealing time. A significant increase in magnetoresistance is observed for short annealing times (of the order of minutes) and is correlated with a relatively small reduction in 1/f noise. In contrast, a significant reduction in 1/f noise is observed for long annealing times (of the order of hours) accompanied by a small change in magnetoresistance. After annealing for 2 hours, the 1/f noise decreases by three orders of magnitude. Transmission electron microscopy and slow positron annihilation results implicate the cause being micro-structural changes in the MgO layers and interfaces following different annealing times. The internal vacancies in the MgO layers gather into vacancy clusters to reduce the defect density after short annealing times, whereas the MgO/NiFe and the NiFe/MgO interfaces improve significantly after long annealing times with the amorphous MgO layers gradually crystallizing following the release of interfacial stress.

  8. Slow positron beam production by a 14 MeV C.W. electron accelerator

    Science.gov (United States)

    Begemann, M.; Gräff, G.; Herminghaus, H.; Kalinowsky, H.; Ley, R.

    1982-10-01

    A 14 MeV c.w. electron accelerator is used for pair production in a tungsten target of 0.7 radiation lengths thickness. A small fraction of the positrons is thermalized and diffuses out of the surface ofsurface of a well annealed tungsten foil coated with MgO which is positioned immediately behind the target. The slow positrons are extracted from the target region and magnetically guided over a distance of 10 m onto a channelplate multiplier at the end of an S-shaped solenoid. The positrons are identified by their annihilation radiation using two NaI-detectors. The intensity of the slow positrons is proportional to the accelerator electron beam current. The maximum intensity of 2.2 × 10 5 slow positrons per second reaching thedetector at an accelerator current of 15 μA was limited by the power deposited in the uncooled target. The energy of the positrons is concentrated in a small region at about 1 eV and clearly demonstrates the emission of thermal positrons.

  9. Slow positron beam production by a 14 MeV c.w. electron accelerator

    International Nuclear Information System (INIS)

    Begemann, M.; Graeff, G.; Herminghaus, H.; Kalinowsky, H.; Ley, R.

    1982-01-01

    A 14 MeV c.w. electron accelerator is used for pair production in a tungsten target of 0.7 radiation lengths thickness. A small fraction of the positrons is thermalized and diffuses out of the surface of a well annealed tungsten foil coated with MgO which is positioned immediately behind the target. The slow positrons are extracted from the target region and magnetically guided over a distance of 10 m onto a channelplate multiplier at the end of an S-shaped solenoid. The positrons are identified by their annihilation radiation using two Nal-detectors. The intensity of the slow positrons is proportional to the accelerator electron beam current. The maximum intensity of 2.2 x 10 5 slow positrons per second reaching the detector at an accelerator current of 15 μA was limited by the power deposited in the uncooled target. The energy of the positrons is concentrated in a small region at about 1 eV and clearly demonstrates the emission of thermal positrons. (orig.)

  10. Post-Mesozoic Rapid Increase of Seawater Mg/Ca due to Enhanced Mantle-Seawater Interaction

    Science.gov (United States)

    Ligi, Marco; Bonatti, Enrico; Cuffaro, Marco; Brunelli, Daniele

    2013-01-01

    The seawater Mg/Ca ratio increased significantly from ~ 80 Ma to present, as suggested by studies of carbonate veins in oceanic basalts and of fluid inclusions in halite. We show here that reactions of mantle-derived peridotites with seawater along slow spreading mid-ocean ridges contributed to the post-Cretaceous Mg/Ca increase. These reactions can release to modern seawater up to 20% of the yearly Mg river input. However, no significant peridotite-seawater interaction and Mg-release to the ocean occur in fast spreading, East Pacific Rise-type ridges. The Mesozoic Pangean superocean implies a hot fast spreading ridge system. This prevented peridotite-seawater interaction and Mg release to the Mesozoic ocean, but favored hydrothermal Mg capture and Ca release by the basaltic crust, resulting in a low seawater Mg/Ca ratio. Continent dispersal and development of slow spreading ridges allowed Mg release to the ocean by peridotite-seawater reactions, contributing to the increase of the Mg/Ca ratio of post-Mesozoic seawater. PMID:24067442

  11. Engineered carbon (biochar) prepared by direct pyrolysis of Mg-accumulated tomato tissues: characterization and phosphate removal potential.

    Science.gov (United States)

    Yao, Ying; Gao, Bin; Chen, Jianjun; Zhang, Ming; Inyang, Mandu; Li, Yuncong; Alva, Ashok; Yang, Liuyan

    2013-06-01

    An innovative method was developed to produce engineered biochar from magnesium (Mg) enriched tomato tissues through slow pyrolysis in a N2 environment. Tomato plants treated with 25mM Mg accumulated much higher level of Mg in tissue, indicating Mg can be substantially enriched in tomato plants, and pyrolysis process further concentrated Mg in the engineered biochar (8.8% Mg). The resulting Mg-biochar composites (MgEC) showed better sorption ability to phosphate (P) in aqueous solutions compared to the other four tomato leaves biochars. Statistical analysis showed a strong and significant correlation between P removal rate and biochar Mg content (R(2)=0.78, and p<0.001), indicating the enriched Mg in the engineered biochar is the main factor controlling its P removal ability. SEM-EDX, XRD and XPS analyses showed that nanoscale Mg(OH)2 and MgO particles were presented on the surface of MgEC, which serve as the main adsorption sites for aqueous P. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Alterations of Mg2+ After Hemorrhagic Shock.

    Science.gov (United States)

    Lee, Mun-Young; Yang, Dong Kwon; Kim, Shang-Jin

    2017-11-01

    Hemorrhagic shock is generally characterized by hemodynamic instability with cellular hypoxia and diminishing cellular function, resulting from an imbalance between systemic oxygen delivery and consumption and redistribution of fluid and electrolytes. Magnesium (Mg) is the fourth most abundant cation overall and second most abundant intracellular cation in the body and an essential cofactor for the energy production and cellular metabolism. Data for blood total Mg (tMg; free-ionized, protein-bound, and anion-bound forms) and free Mg 2+ levels after a traumatic injury are inconsistent and only limited information is available on hemorrhagic effects on free Mg 2+ as the physiologically active form. The aim of this study was to determine changes in blood Mg 2+ and tMg after hemorrhage in rats identifying mechanism and origin of the changes in blood Mg 2+ . Hemorrhagic shock produced significant increases in blood Mg 2+ , plasma tMg, Na + , K + , Cl - , anion gap, partial pressures of oxygen, glucose, and blood urea nitrogen but significant decreases in RBC tMg, blood Ca 2+ , HCO 3 - , pH, partial pressures of carbon dioxide, hematocrit, hemoglobin, total cholesterol, and plasma/RBC ATP. During hemorrhagic shock, K + , anion gap, and BUN showed significant positive correlations with changes in blood Mg 2+ level, while Ca 2+ , pH, and T-CHO correlated to Mg 2+ in a negative manner. In conclusion, hemorrhagic shock induced an increase in both blood-free Mg 2+ and tMg, resulted from Mg 2+ efflux from metabolic damaged cell with acidosis and ATP depletion.

  13. Identifying factors contributing to slow growth in pigs.

    Science.gov (United States)

    He, Y; Deen, J; Shurson, G C; Wang, L; Chen, C; Keisler, D H; Li, Y Z

    2016-05-01

    Pigs that grow slower than their contemporaries can cause complications for animal welfare and profitability. This study was conducted to investigate factors that may contribute to slow growth of pigs. Pigs ( = 440) farrowed by 65 sows were monitored from birth to market. Pigs were categorized as slow, average, and fast growers based on market weight adjusted to 170 d of age (slow growers were 125 kg). Blood samples were collected from 48 focal pigs at 9 and 21 wk of age and analyzed for hormone and free AA concentrations. Data were analyzed using the Mixed and Logistic procedures of SAS. Slow-growing pigs accounted for 10% of pigs marketed, average growers accounted for 49% of pigs marketed, and fast growers accounted for 41% of pigs marketed. Compared with fast growers, slow growers were lighter at birth ( ratio = 2.17, 95% confidence interval = 1.19 to 3.96, = 0.01). Litter size and parity of the pigs' dam were not associated with slow growth. These results suggest that low concentrations of IGF-1, insulin, leptin, and AA may contribute to or be associated with slow growth in pigs.

  14. Modeling and stabilities of Mg/MgH2 interfaces: A first-principles investigation

    Directory of Open Access Journals (Sweden)

    Jia-Jun Tang

    2014-07-01

    Full Text Available We have theoretically investigated the modeling and the structural stabilities of various Mg/MgH2 interfaces, i.e. Mg(101¯0/MgH2(210, Mg(0001/MgH2(101 and Mg(101¯0/MgH2(101, and provided illuminating insights into Mg/MgH2 interface. Specifically, the main factors, which impact the interfacial energies, are fully considered, including surface energies of two phases, mutual lattice constants of interface model, and relative position of two phases. The surface energies of Mg and MgH2, on the one hand, are found to be greatly impacting the interfacial energies, reflected by the lowest interfacial energy of Mg(0001/MgH2(101 which is comprised of two lowest energy surfaces. On the other hand, it is demonstrated that the mutual lattice constants and the relative position of two phases lead to variations of interfacial energies, thus influencing the interface stabilities dramatically. Moreover, the Mg-H bonding at interface is found to be the determinant of Mg/MgH2 interface stability. Lastly, interfacial and strain effects on defect formations are also studied, both of which are highly facilitating the defect formations. Our results provide a detailed insight into Mg/MgH2 interface structures and the corresponding stabilities.

  15. Azimuthal asymmetry of slow particles in high energy nuclear interaction

    International Nuclear Information System (INIS)

    Sarkar, Subir; Goswami, T.D.

    2002-01-01

    An asymmetry in the angular distribution of slow particles in the azimuthal plane has been observed during high energy nuclear disintegration of photo emulsion nuclei exposed to 1.8 GeV/c k - and 20 GeV/c protons. The mechanism of disintegration is not in accordance with the cascade-evaporation model, which is based on isotropic emission of slow particles. Deviation from isotropy indicates that some of the slow particles might be emitted well before the thermal equilibrium is reached in the disintegrating system. (author)

  16. Theory of neutron slowing down in nuclear reactors

    CERN Document Server

    Ferziger, Joel H; Dunworth, J V

    2013-01-01

    The Theory of Neutron Slowing Down in Nuclear Reactors focuses on one facet of nuclear reactor design: the slowing down (or moderation) of neutrons from the high energies with which they are born in fission to the energies at which they are ultimately absorbed. In conjunction with the study of neutron moderation, calculations of reactor criticality are presented. A mathematical description of the slowing-down process is given, with particular emphasis on the problems encountered in the design of thermal reactors. This volume is comprised of four chapters and begins by considering the problems

  17. Slow Food: por um alimento bom, limpo e justo

    OpenAIRE

    Porazzi, Fabiele

    2012-01-01

    REVIEW:PETRINI, Carlo. Slow Food: princípios da nova gastronomia. Trad. de Renata Lúcia Botina. São Paulo: Editora Senac, 2009. 245 p. RESEÑA:PETRINI, Carlo. Slow Food: princípios da nova gastronomia. Trad. de Renata Lúcia Botina. São Paulo: Editora Senac, 2009. 245 p. http://dx.doi.org/10.5007/1807-1384.2012v9n1p384 RESENHA:PETRINI, Carlo. Slow Food: princípios da nova gastronomia. Trad. de Renata Lúcia Botina. São Paulo: Editora Senac, 2009. 245 p.

  18. Face recognition using slow feature analysis and contourlet transform

    Science.gov (United States)

    Wang, Yuehao; Peng, Lingling; Zhe, Fuchuan

    2018-04-01

    In this paper we propose a novel face recognition approach based on slow feature analysis (SFA) in contourlet transform domain. This method firstly use contourlet transform to decompose the face image into low frequency and high frequency part, and then takes technological advantages of slow feature analysis for facial feature extraction. We named the new method combining the slow feature analysis and contourlet transform as CT-SFA. The experimental results on international standard face database demonstrate that the new face recognition method is effective and competitive.

  19. Slow light invisibility, teleportation, and other mysteries of light

    CERN Document Server

    Perkowitz, Sidney

    2011-01-01

    Slow Light is a popular treatment of today's astonishing breakthroughs in the science of light. Even though we don't understand light's quantum mysteries, we can slow it to a stop and speed it up beyond its Einsteinian speed limit, 186,000 miles/sec; use it for quantum telecommunications; teleport it; manipulate it to create invisibility; and perhaps generate hydrogen fusion power with it. All this is lucidly presented for non-scientists who wonder about teleportation, Harry Potter invisibility cloaks, and other fantastic outcomes. Slow Light shows how the real science and the fantasy inspire

  20. Slow extraction from the IHEP accelerator by internal target scattering

    International Nuclear Information System (INIS)

    Maksimov, A.V.

    1994-01-01

    The existing slow extraction system is not able to satisfy the required quality of the beam time structure in the intensity region 10 10 - 10 11 ppp. Calculations on simulation of slow extraction by internal target scattering are presented. Two regime of slow extraction are analysed: nonresonant and resonant extraction by target scattering. Resonant extraction by target scattering is able to ensure intensity of extracted beam up to 10 11 . The agreement between calculations and experimental data is good enough. The calculation of extraction possibility by thin W-target scattering are also presented. In this case the extraction efficiency is about 85%. 15 refs., 6 figs

  1. Biodegradation of Mg-14Li alloy in simulated body fluid: A proof-of-concept study

    Directory of Open Access Journals (Sweden)

    Xiao-Bo Chen

    2018-03-01

    Full Text Available High corrosion kinetics and localised corrosion progress are the primary concerns arising from the clinical implementation of magnesium (Mg based implantable devices. In this study, a binary Mg-lithium (Li alloy consisting a record high Li content of 14% (in weight was employed as model material aiming to yield homogenous and slow corrosion behaviour in a simulated body fluid, i.e. minimum essential medium (MEM, in comparison to that of generic Mg alloy AZ31 and biocompatible Mg-0.5Zn-0.5Ca counterparts. Scanning electron microscopy examination reveals single-phase microstructural characteristics of Mg-14Li (β-Li, whilst the presence of insoluble phases, cathodic to α-Mg matrix, in AZ31 and Mg-0.5Zn-0.5Ca. Though slight differences exist in the corrosion kinetics of all the specimens over a short-term time scale (no longer than 60 min, as indicated by potentiodynamic polarisation and electrochemical impedance spectroscopy, profound variations are apparent in terms of immersion tests, i.e. mass loss and hydrogen evolution measurements (up to 7 days. Cross-sectional micrographs unveil severe pitting corrosion in AZ31 and Mg-0.5Zn-0.5Ca, but not the case for Mg-14Li. X-ray diffraction patterns and X-ray photoelectron spectroscopy confirm that a compact film (25 μm in thickness consisting of lithium carbonate (Li2CO3 and calcium hydroxide was generated on the surface of Mg-14Li in MEM, which contributes greatly to its low corrosion rate. It is proposed therefore that the single-phase structure and formation of protective and defect-free Li2CO3 film give rise to the controlled and homogenous corrosion behaviour of Mg-14Li in MEM, providing new insights for the exploration of biodegradable Mg materials.

  2. Omega-conotoxin- and nifedipine-insensitive voltage-operated calcium channels mediate K(+)-induced release of pro-thyrotropin-releasing hormone-connecting peptides Ps4 and Ps5 from perifused rat hypothalamic slices.

    Science.gov (United States)

    Valentijn, K; Tranchand Bunel, D; Vaudry, H

    1992-07-01

    The rat thyrotropin-releasing hormone (TRH) precursor (prepro-TRH) contains five copies of the TRH progenitor sequence linked together by intervening sequences. Recently, we have shown that the connecting peptides prepro-TRH-(160-169) (Ps4) and prepro-TRH-(178-199) (Ps5) are released from rat hypothalamic neurones in response to elevated potassium concentrations, in a calcium-dependent manner. In the present study, the role of voltage-operated calcium channels in potassium-induced release of Ps4 and Ps5 was investigated, using a perifusion system for rat hypothalamic slices. The release of Ps4 and Ps5 stimulated by potassium (70 mM) was blocked by the inorganic ions Co2+ (2.6 mM) and Ni2+ (5 mM). In contrast, the stimulatory effect of KCl was insensitive to Cd2+ (100 microM). The dihydropyridine antagonist nifedipine (10 microM) had no effect on K(+)-evoked release of Ps4 and Ps5. Furthermore, the response to KCl was not affected by nifedipine (10 microM) in combination with diltiazem (1 microM), a benzothiazepine which increases the affinity of dihydropyridine antagonists for their receptor. The dihydropyridine agonist BAY K 8644, at concentrations as high as 1 mM, did not stimulate the basal secretion of Ps4 and Ps5. In addition, BAY K 8644 had no potentiating effect on K(+)-induced release of Ps4 and Ps5. The marine cone snail toxin omega-conotoxin, a blocker of both L- and N-type calcium channels had no effect on the release of Ps4 and Ps5 stimulated by potassium. Similarly, the omega-conopeptide SNX-111, a selective blocker of N-type calcium channels, did not inhibit the stimulatory effect of potassium. The release of Ps4 and Ps5 evoked by high K+ was insensitive to the non-selective calcium channel blocker verapamil (20 microM). Amiloride (1 microM), a putative blocker of T-type calcium channels, did not affect KCl-induced secretion of the two connecting peptides. Taken together, these results indicate that two connecting peptides derived from the pro-TRH, Ps

  3. Slow light enhancement and limitations in periodic media

    DEFF Research Database (Denmark)

    Grgic, Jure

    in the vicinity of the band edge. The minimum attainable group velocity will depend on the amount of imperfections. Since imperfections are inherited as part of any periodic structure it is necessary to take them into account when we are interested in slow light applications. Slowly propagating light gives rise......Properties of periodic dielectric media have attracted a big interest in the last two decades due to numerous exciting physical phenomena that cannot occur in homogeneous media. Due to their strong dispersive properties, the speed of light can be significantly slowed down in periodic structures....... When light velocity is much smaller than the speed of light in a vacuum, we describe this phenomena as slow light. In this thesis, we analyze important properties of slow light enhancement and limitations in periodic structures. We analyze quantitatively and qualitatively different technologies...

  4. Critical slowing down and error analysis in lattice QCD simulations

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Stefan [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Sommer, Rainer; Virotta, Francesco [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2010-09-15

    We study the critical slowing down towards the continuum limit of lattice QCD simulations with Hybrid Monte Carlo type algorithms. In particular for the squared topological charge we find it to be very severe with an effective dynamical critical exponent of about 5 in pure gauge theory. We also consider Wilson loops which we can demonstrate to decouple from the modes which slow down the topological charge. Quenched observables are studied and a comparison to simulations of full QCD is made. In order to deal with the slow modes in the simulation, we propose a method to incorporate the information from slow observables into the error analysis of physical observables and arrive at safer error estimates. (orig.)

  5. Preparation and characterization of Slow Release Formulations of ...

    African Journals Online (AJOL)

    alginate beads and characterize the resulting slow release formulations (SRFs) using scanning electron microscopy (SEM), and Fourier Transform infrared spectroscopy (FTIR). Two sets of formulations were made by extrusion into 0.25 M calcium ...

  6. Critical slowing down and error analysis in lattice QCD simulations

    International Nuclear Information System (INIS)

    Schaefer, Stefan; Sommer, Rainer; Virotta, Francesco

    2010-09-01

    We study the critical slowing down towards the continuum limit of lattice QCD simulations with Hybrid Monte Carlo type algorithms. In particular for the squared topological charge we find it to be very severe with an effective dynamical critical exponent of about 5 in pure gauge theory. We also consider Wilson loops which we can demonstrate to decouple from the modes which slow down the topological charge. Quenched observables are studied and a comparison to simulations of full QCD is made. In order to deal with the slow modes in the simulation, we propose a method to incorporate the information from slow observables into the error analysis of physical observables and arrive at safer error estimates. (orig.)

  7. Very Slow Speed Axial Motion Reluctance Motor | Agu | Nigerian ...

    African Journals Online (AJOL)

    Abstract. This paper presents the scheme for a very slow speed linear machine which uses conventional laminations and with which speeds of the same low order as that of the screw-thread motor can be obtained.

  8. Structural slow light can enhance Beer-Lambert absorption

    OpenAIRE

    Dicaire Isabelle; Chin Sanghoon; Thévenaz Luc

    2011-01-01

    We experimentally demonstrate that structural slow light can enhance Beer-Lambert absorption. A 4-fold reduction of the group velocity induced by mere cavity effects has caused an increase of molecular absorption by 130%.

  9. Techniques for slow positron beam generation and the applications

    International Nuclear Information System (INIS)

    Okada, Sohei

    1994-01-01

    Slow positron beams have been expected to be a powerful tool for observation of nature in wide range of research fields from materials science to basic physics, chemistry and biology. In this paper, at first, the beam technology is reviewed, which includes the positron generation, the transformation to slow positron beams and the beam manipulation such as beam stretching, bunching and brightness enhancement. Next, the present status of the slow positron beam applications to a variety of fields is demonstrated in terms of special characteristics of positron, that is, depth controllability, surface sensitivity, unique ionization channels and elemental anti-particle properties. Finally, prospects to produce intense slow positron beams are described. (author) 65 refs

  10. Electron heating and current drive by mode converted slow waves

    International Nuclear Information System (INIS)

    Majeski, R.; Phillips, C.K.; Wilson, J.R.

    1994-01-01

    An approach to obtaining efficient single pass mode conversion at high parallel wave number from the fast magnetosonic wave to the slow ion Bernstein wave, in a two-ion species tokamak plasma, is described. The intent is to produce localized electron heating or current drive via the mode converted slow wave. In particular, this technique can be adapted to off-axis current drive for current profile control. Modeling for the case of deuterium-tritium plasmas in TFTR is presented

  11. Slow-light enhancement of Beer-Lambert-Bouguer absorption

    DEFF Research Database (Denmark)

    Mortensen, Asger; Xiao, Sanshui

    2007-01-01

    We theoretically show how slow light in an optofluidic environment facilitates enhanced light-matter interactions, by orders of magnitude. The proposed concept provides strong opportunities for improving existing miniaturized chemical absorbance cells for Beer-Lambert-Bouguer absorption measureme......We theoretically show how slow light in an optofluidic environment facilitates enhanced light-matter interactions, by orders of magnitude. The proposed concept provides strong opportunities for improving existing miniaturized chemical absorbance cells for Beer-Lambert-Bouguer absorption...

  12. Exploring carrier dynamics in semiconductors for slow light

    DEFF Research Database (Denmark)

    Mørk, Jesper; Xue, Weiqi; Chen, Yaohui

    2009-01-01

    We give an overview of recent results on slow and fast light in active semiconductor waveguides. The cases of coherent population oscillations as well as electromagnetically induced transparency are covered, emphasizing the physics and fundamental limitations.......We give an overview of recent results on slow and fast light in active semiconductor waveguides. The cases of coherent population oscillations as well as electromagnetically induced transparency are covered, emphasizing the physics and fundamental limitations....

  13. Neutron slowing-down time in finite water systems

    International Nuclear Information System (INIS)

    Hirschberg, S.

    1981-11-01

    The influence of the size of a moderator system on the neutron slowing-down time has been investigated. The experimental part of the study was performed on six cubes of water with side lengths from 8 to 30 cm. Neutrons generated in pulses of about 1 ns width were slowed down from 14 MeV to 1.457 eV. The detection method used was based on registration of gamma radiation from the main capture resonance of indium. The most probable slowing-down times were found to be 778 +- 23 ns and 898 +- 25 ns for the smallest and for the largest cubes, respectively. The corresponding mean slowing-down times were 1205 +- 42 ns and 1311 +- 42 ns. In a separate measurement series the space dependence of the slowing-down time close to the source was studied. These experiments were supplemented by a theoretical calculation which gave an indication of the space dependence of the slowingdown time in finite systems. The experimental results were compared to the slowing-down times obtained from various theoretical approaches and from Monte Carlo calculations. All the methods show a decrease of the slowing-down time with decreasing size of the moderator. This effect was least pronounced in the experimental results, which can be explained by the fact the measurements are spatially dependent. The agreement between the Monte Carlo results and those obtained using the diffusion approximation or the age-diffusion theory is surprisingly good, especially for large systems. The P1 approximation, on the other hand, leads to an overestimation of the effect of the finite size on the slowing-down time. (author)

  14. Perceptions of the Slow Food Cultural Trend among the Youth

    OpenAIRE

    Lelia Voinea; Anca Atanase; Ion Schileru

    2016-01-01

    As they become increasingly aware of the importance of healthy eating and of the serious food imbalance caused by the overconsumption of industrial, ultra-processed and superorganoleptic food, consumers are now beginning to turn their attention to food choices guaranteeing both individual health and also of the environment . Thus, in recent years we are witnessing the rise of a cultural trend ‒ Slow Food. Slow Food has become an international movement that advocates for satisfying culinary pl...

  15. Development of slow pyrolysis business operations in Finland - Hidaspyro

    Energy Technology Data Exchange (ETDEWEB)

    Fagernas, L. [VTT Technical Research Centre of Finland, Espoo (Finland)], email: leena.fagernas@vtt.fi

    2012-07-01

    Birch distillate, a by-product in slow pyrolysis process of charcoal production, was found to be a promising source for biological pesticides. However, product commercialization was problematic, for EU registration is costly, and composition, active ingredients and ecotoxicological properties were not known. In addition, constant quality and process optimisation were needed. More collaboration between SMEs and research institutes was required. The primary aim was to support and develop slow pyrolysis business operations of SMEs in Finland by generating knowledge that was needed.

  16. The space charge effects on the slow extraction process

    International Nuclear Information System (INIS)

    Ohmori, Chihiro.

    1992-06-01

    The calculation of the slow extraction which includes the space charge effects has been performed for the Compressor/Stretcher Ring (CSR) of the proposed Japanese Hadron Project. We have investigated the slow extraction of 1 GeV proton beam with an average current of 100μA. Calculation shows not only the emittance growth of the extracted beam but also decrease of the extraction efficiency and discontinuity of beam spill. (author)

  17. Electron heating and current drive by mode converted slow waves

    International Nuclear Information System (INIS)

    Majeski, R.; Phillips, C.K.; Wilson, J.R.

    1994-08-01

    An approach to obtaining efficient single pass mode conversion at high parallel wavenumber from the fast magnetosonic wave to the slow ion Bernstein wave, in a two ion species tokamak plasma, is described. The intent is to produce localized electron heating or current drive via the mode converted slow wave. In particular, this technique can be adapted to off-axis current drive for current profile control. Modelling for the case of deuterium-tritium plasmas in TFTR is presented

  18. Slow light in semiconductor waveguides: Theory and experiment

    DEFF Research Database (Denmark)

    Mørk, Jesper; Öhman, Filip; Poel, Mike van der

    2007-01-01

    Slow light in multi-section quantum well waveguide structure is realized using either coherent population oscillations (CPO) and electromagnetically induced transparency (EIT) is studied. The properties of the two schemes are compared and discussed.......Slow light in multi-section quantum well waveguide structure is realized using either coherent population oscillations (CPO) and electromagnetically induced transparency (EIT) is studied. The properties of the two schemes are compared and discussed....

  19. Transformation of Mg-bearing amorphous calcium carbonate to Mg-calcite - In situ monitoring

    Science.gov (United States)

    Purgstaller, Bettina; Mavromatis, Vasileios; Immenhauser, Adrian; Dietzel, Martin

    2016-02-01

    The formation of Mg-bearing calcite via an amorphous precursor is a poorly understood process that is of relevance for biogenic and abiogenic carbonate precipitation. In order to gain an improved insight on the controls of Mg incorporation in calcite formed via an Mg-rich amorphous calcium carbonate (Mg-ACC) precursor, the precipitation of Mg-ACC and its transformation to Mg-calcite was monitored by in situ Raman spectroscopy. The experiments were performed at 25.0 ± 0.03 °C and pH 8.3 ± 0.1 and revealed two distinct pathways of Mg-calcite formation: (i) At initial aqueous Mg/Ca molar ratios ⩽ 1:6, Mg-calcite formation occurs via direct precipitation from solution. (ii) Conversely, at higher initial Mg/Ca molar ratios, Mg-calcite forms via an intermediate Mg-rich ACC phase. In the latter case, the final product is a calcite with up to 20 mol% Mg. This Mg content is significant higher than that of the Mg-rich ACC precursor phase. Thus, a strong net uptake of Mg ions from the solution into the crystalline precipitate throughout and also subsequent to ACC transformation is postulated. Moreover, the temporal evolution of the geochemical composition of the reactive solution and the Mg-ACC has no significant effect on the obtained ;solubility product; of Mg-ACC. The enrichment of Mg in calcite throughout and subsequent to Mg-ACC transformation is likely affected by the high aqueous Mg/Ca ratio and carbonate alkalinity concentrations in the reactive solution. The experimental results have a bearing on the formation mechanism of Mg-rich calcites in marine early diagenetic environments, where high carbonate alkalinity concentrations are the rule rather than the exception, and on the insufficiently investigated inorganic component of biomineralisation pathways in many calcite secreting organisms.

  20. Slow wave maturation on a visual working memory task.

    Science.gov (United States)

    Barriga-Paulino, Catarina I; Rodríguez-Martínez, Elena I; Rojas-Benjumea, Ma Ángeles; Gómez, Carlos M

    2014-07-01

    The purpose of the present study is to analyze how the Slow Wave develops in the retention period on a visual Delayed Match-to-Sample task performed by 170 subjects between 6 and 26 years old, divided into 5 age groups. In addition, a neuropsychological test (Working Memory Test Battery for Children) was correlated with this Event Related Potential (ERP) in order to observe possible relationships between Slow Wave maturation and the components of Baddeley and Hitch's Working Memory model. The results showed a slow negativity during the retention period in the posterior region in all the age groups, possibly resulting from sustained neural activity related to the visual item presented. In the anterior region, a positive slow wave was observed in the youngest subjects. Dipole analysis suggests that this fronto-central positivity in children (6-13 years old) consists of the positive side of the posterior negativity, once these subjects only needed two posterior dipoles to explain almost all the neural activity. Negative correlations were shown between the Slow Wave and the Working Memory Test Battery for Children, indicating a commonality in assessing Working Memory with the Slow Wave and the neuropsychological testing. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Beneficial Effects of Slow Steaming in Bulk Freight Markets

    Directory of Open Access Journals (Sweden)

    Sarah Boone

    2017-12-01

    Full Text Available Slow steaming has recently been adopted into normal practice by many maritime shipping companies for the fuel and monetary savings it offers. The practice also offers savings in Greenhouse Gas (GHG emissions. With regulations coming into play such as the 2020 sulfur cap, slow steaming may be the least costly option for some maritime companies to adjust their operations. While some have accepted the new practice, there are still companies and vessels that see this exercise as a loss of revenue due to the extra time it takes to deliver goods to their destination. This paper reviews how the method of rating ships by their GHG emissions per nautical mile can be directly related to slow steaming. We propose that ships with poor ratings (E, F, G find mandatory regulations to slow steam or improve their CO2 output in some way. Those with superior ratings (A, B, C, D would benefit from incentives packages tied to their implementation of slow steaming practices. It will also examine how slow steaming benefits maritime businesses both economically and environmentally to find ways to lower their emissions and discusses the possible chain reaction that may occur if these eco-friendly shipping practices are observed.

  2. Implications of the Deep Minimum for Slow Solar Wind Origin

    Science.gov (United States)

    Antiochos, S. K.; Mikic, Z.; Lionello, R.; Titov, V. S.; Linker, J. A.

    2009-12-01

    The origin of the slow solar wind has long been one of the most important problems in solar/heliospheric physics. Two observational constraints make this problem especially challenging. First, the slow wind has the composition of the closed-field corona, unlike the fast wind that originates on open field lines. Second, the slow wind has substantial angular extent, of order 30 degrees, which is much larger than the widths observed for streamer stalks or the widths expected theoretically for a dynamic heliospheric current sheet. We propose that the slow wind originates from an intricate network of narrow (possibly singular) open-field corridors that emanate from the polar coronal hole regions. Using topological arguments, we show that these corridors must be ubiquitous in the solar corona. The total solar eclipse in August 2008, near the lowest point of the Deep Minimum, affords an ideal opportunity to test this theory by using the ultra-high resolution Predictive Science's (PSI) eclipse model for the corona and wind. Analysis of the PSI eclipse model demonstrates that the extent and scales of the open-field corridors can account for both the angular width of the slow wind and its closed-field composition. We discuss the implications of our slow wind theory for the structure of the corona and heliosphere at the Deep Minimum and describe further observational and theoretical tests. This work has been supported by the NASA HTP, SR&T, and LWS programs.

  3. Slowness and sparseness have diverging effects on complex cell learning.

    Directory of Open Access Journals (Sweden)

    Jörn-Philipp Lies

    2014-03-01

    Full Text Available Following earlier studies which showed that a sparse coding principle may explain the receptive field properties of complex cells in primary visual cortex, it has been concluded that the same properties may be equally derived from a slowness principle. In contrast to this claim, we here show that slowness and sparsity drive the representations towards substantially different receptive field properties. To do so, we present complete sets of basis functions learned with slow subspace analysis (SSA in case of natural movies as well as translations, rotations, and scalings of natural images. SSA directly parallels independent subspace analysis (ISA with the only difference that SSA maximizes slowness instead of sparsity. We find a large discrepancy between the filter shapes learned with SSA and ISA. We argue that SSA can be understood as a generalization of the Fourier transform where the power spectrum corresponds to the maximally slow subspace energies in SSA. Finally, we investigate the trade-off between slowness and sparseness when combined in one objective function.

  4. Persistent benefits of slow titration of paroxetine in a six-month follow-up.

    Science.gov (United States)

    Olgiati, Paolo; Serretti, Alessandro

    2015-09-01

    Paroxetine titration may be difficult in older individuals as they are more sensitive to side effects. The current study extends to 6 months our previously published report in which paroxetine was started at 2.5 mg/day and slowly increased by 2.5 mg on alternate days (slow titration) or rapidly titrated to target dose from 10 mg/day (standard titration) in a naturalistic setting. Here, the follow-up period was extended to 26 weeks. We performed an intent-to-treat analysis of 47 subjects from the original sample (major depressive disorder and/or generalized anxiety disorder (GAD); >60 years of age). Missing evaluations were replaced by last observations carried forward. GAD was included as a stratification factor. Patients in whom paroxetine was slowly up-titrated were more likely to remit (84.0% vs 54.5%; p = 0.028) and had lower core depression (p = 0.0015) and psychic anxiety levels (p = 0.006) after 26 weeks. Dropout rate was 20% in the slow titration group compared with 77.3% in the standard titration arm (p titration groups in the subsample without GAD. Despite some limitations, these findings suggest that paroxetine treatment should be started at lower doses in older depressed patients and slowly up-titrated. This strategy would allow to increase antidepressant response and the likelihood of completing treatment cycle in patients with high anxiety levels and GAD comorbidity. Copyright © 2015 John Wiley & Sons, Ltd.

  5. In vitro study of nanostructured diopside coating on Mg alloy orthopedic implants

    Energy Technology Data Exchange (ETDEWEB)

    Razavi, Mehdi, E-mail: mehdi.razavi@okstate.edu [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Fathi, Mohammadhossein [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Savabi, Omid [Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Vashaee, Daryoosh [School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Tayebi, Lobat, E-mail: lobat.tayebi@okstate.edu [School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States)

    2014-08-01

    The high corrosion rate of Mg alloys has hindered their application in various areas, particularly for orthopedic applications. In order to decrease the corrosion rate and to improve the bioactivity, mechanical stability and cytocompatibility of the Mg alloy, nanostructured diopside (CaMgSi{sub 2}O{sub 6}) has been coated on AZ91 Mg alloy using a combined micro arc oxidation (MAO) and electrophoretic deposition (EPD) method. The crystalline structure, the morphology and the composition of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electrochemical corrosion test, immersion test, and compression test were used to evaluate the corrosion resistance, the in vitro bioactivity and the mechanical stability of the samples, respectively. The cytocompatibility of the samples was tested by the cell viability and the cell attachment of L-929 cells. The results confirmed that the diopside coating not only slows down the corrosion rate, but also enhances the in vitro bioactivity, mechanical stability and cytocompatibility of AZ91 Mg alloy. Therefore, Mg alloy coated with nanostructured diopside offers a promising approach for biodegradable bone implants. - Highlights: • The diopside coating was applied on Mg alloy using the combined MAO and EPD methods. • The corrosion resistance of the diopside coated Mg alloy was noticeably improved. • The in vitro bioactivity of the diopside coated Mg alloy was considerably increased. • The mechanical stability of biodegradable Mg alloy was enhanced by diopside coating. • The cytocompatibility of the Mg alloy was improved employing diopside coating.

  6. Re-examining the 26Mg(α ,α')26Mg reaction: Probing astrophysically important states in 26Mg

    Science.gov (United States)

    Adsley, P.; Brümmer, J. W.; Li, K. C. W.; Marín-Lámbarri, D. J.; Kheswa, N. Y.; Donaldson, L. M.; Neveling, R.; Papka, P.; Pellegri, L.; Pesudo, V.; Pool, L. C.; Smit, F. D.; van Zyl, J. J.

    2017-11-01

    Background: The 22Ne(α ,n )25Mg reaction is one of the neutron sources for the s process in massive stars. The properties of levels in 26Mg above the α -particle threshold control the strengths of the 22Ne(α ,n )25Mg and 22Ne(α ,γ )26Mg reactions. The strengths of these reactions as functions of temperature are one of the major uncertainties in the s process. Purpose: Information on the existence, spin, and parity of levels in 26Mg can assist in constraining the strengths of the 22Ne(α ,γ )26Mg and 22Ne(α ,n )25Mg reactions, and therefore in constraining s -process abundances. Methods: Inelastically scattered α particles from a 26Mg target were momentum-analyzed in the K600 magnetic spectrometer at iThemba LABS, South Africa. The differential cross sections of states were deduced from the focal-plane trajectory of the scattered α particles. Based on the differential cross sections, spin and parity assignments to states are made. Results: A newly assigned 0+ state was observed in addition to a number of other states, some of which can be associated with states observed in other experiments. Some of the deduced Jπ values of the states observed in the present study show discrepancies with those assigned in a similar experiment performed at RCNP Osaka. The reassignments and additions of the various states can strongly affect the reaction rate at low temperatures. Conclusion: The number, location, and assignment of levels in 26Mg that may contribute to the 22Ne+α reactions are not clear. Future experimental investigations of 26Mg must have an extremely good energy resolution to separate the contributions from different levels. Coincidence experiments of 26Mg provide a possible route for future investigations.

  7. Antibacterial biodegradable Mg-Ag alloys

    Directory of Open Access Journals (Sweden)

    D Tie

    2013-06-01

    Full Text Available The use of magnesium alloys as degradable metals for biomedical applications is a topic of ongoing research and the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed as implant materials to combine the favourable properties of magnesium with the well-known antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag that contain 1.87 %, 3.82 % and 6.00 % silver by weight, respectively, were cast and processed with solution (T4 and aging (T6 heat treatment.The metallurgical analysis and phase identification showed that all alloys contained Mg4Ag as the dominant β phase. After heat treatment, the mechanical properties of all Mg-Ag alloys were significantly improved and the corrosion rate was also significantly reduced, due to presence of silver. Mg(OH2 and MgO present the main magnesium corrosion products, while AgCl was found as the corresponding primary silver corrosion product. Immersion tests, under cell culture conditions, demonstrated that the silver content did not significantly shift the pH and magnesium ion release. In vitro tests, with both primary osteoblasts and cell lines (MG63, RAW 264.7, revealed that Mg-Ag alloys show negligible cytotoxicity and sound cytocompatibility. Antibacterial assays, performed in a dynamic bioreactor system, proved that the alloys reduce the viability of two common pathogenic bacteria, Staphylococcus aureus (DSMZ 20231 and Staphylococcus epidermidis (DSMZ 3269, and the results showed that the killing rate of the alloys against tested bacteria exceeded 90%. In summary, biodegradable Mg-Ag alloys are cytocompatible materials with adjustable mechanical and corrosion properties and show promising antibacterial activity, which indicates their potential as antibacterial biodegradable implant materials.

  8. Intra-individual comparison of different contrast media concentrations (300 mg, 370 mg and 400 mg iodine) in MDCT

    Energy Technology Data Exchange (ETDEWEB)

    Behrendt, Florian F.; Keil, Sebastian; Plumhans, Cedric; Guenther, Rolf W. [RWTH Aachen University, Department of Diagnostic Radiology, University Hospital, Aachen (Germany); Pietsch, Hubertus; Jost, Gregor; Sieber, Martin A.; Seidensticker, Peter [Bayer Schering Pharma AG, Berlin (Germany); Mahnken, Andreas H. [RWTH Aachen University, Department of Diagnostic Radiology, University Hospital, Aachen (Germany); RWTH Aachen University, Applied Medical Engineering, Helmholtz-Institute for Biomedical Engineering, Aachen (Germany)

    2010-07-15

    To compare intra-individual contrast enhancement in multi-detector-row computed tomography (MDCT) using contrast media (CM) containing 300, 370 and 400 mg iodine per ml (mgI/ml). Six pigs underwent repeated chest MDCT using three different CM (iopromide 300, iopromide 370, iomeprol 400). An identical iodine delivery (IDR) rate of 1.5 gI/s and a constant total iodine dose of 300 mg/kg body weight were used. Dynamic CT were acquired at the level of the pulmonary artery, and the ascending and descending aorta. After the time enhancement curves were computed, the pulmonary and aortic peak enhancement, time to peak and plateau time above 300 HU were calculated. Intra-individual peak contrast enhancement was significantly higher for the 300 mgI/ml contrast medium compared with the 370 and 400 mgI/ml media: pulmonary trunk 595 HU vs 516 HU (p = 0.0093) vs 472HU (p = 0.0005), and aorta 505 HU vs 454 HU (p = 0.0008) vs 439 HU (p = 0.0001), respectively. Comparison of time to peaks showed no significant difference. Plateau times were significantly longer for the 300 mgI/ml than for the 370 and 400 mgI/ml CM at all anatomical sites. Given normalised IDR and total iodine burden, the use of CM with a standard concentration with 300 mg iodine/ml provides improved contrast enhancement compared with highly concentrated CM in the chest. (orig.)

  9. Perceptions of the Slow Food Cultural Trend among the Youth

    Directory of Open Access Journals (Sweden)

    Lelia Voinea

    2016-11-01

    Full Text Available As they become increasingly aware of the importance of healthy eating and of the serious food imbalance caused by the overconsumption of industrial, ultra-processed and superorganoleptic food, consumers are now beginning to turn their attention to food choices guaranteeing both individual health and also of the environment . Thus, in recent years we are witnessing the rise of a cultural trend ‒ Slow Food. Slow Food has become an international movement that advocates for satisfying culinary pleasure, protects biological and cultural diversity, spread taste education, links "green" producers to consumers and believes that gastronomy intersects with politics, agriculture and ecology. Slow Food proposes a holistic approach to food problem, where the economic, sociocultural and environmental aspects are interlinked, being pursued as part of an overall strategy. In order to highlight the manner in which the principles of this cultural trend are perceived by the representatives of the new generation of consumers in Romania, exploratory research marketing was conducted among the students in the second year of the master’s program Quality Management, Expertise and Consumer Protection, from the Faculty of Business and Tourism from the Buchares t University of Economic Studies . The results of this research have shown an insufficient knowledge of Slow Food phenomenon and, especially, the Slow Food network activity in Romania. To show that the Slow Food type of food is a healthier option towards which the future consumer demand should be guided, especially those belonging to the younger generation, an antithetical comparative analysis of the nutritional value of two menus was performed: a suggestive one for the Slow Food feeding style and other one, specific to the fast food style. Slow Food style was considered antithetical to the fast food because many previous studies have shown a preference of the young for the fast-food type products, despite the

  10. A taste of ethical consumption at a slow food festival.

    Science.gov (United States)

    Williams, Lauren T; Germov, John; Fuller, Sascha; Freij, Maria

    2015-08-01

    This paper examines the motives and experiences of attendees at a Slow Food festival to gain an understanding of how people engage with ethical consumer projects. Slow Food is a global social movement aimed at promoting food that is regionally, ethically, and sustainably produced, and convivially consumed. The movement uses culinary tourist events, such as food festivals and farmers' markets, to promote its philosophy and attract new members. There have been no empirical studies of ethical consumption using a Slow Food event as a case study. This study uses an ethnographic approach and a framework of virtue ethics to explore the views of people attending a major Slow Food festival in the city of Melbourne, Australia. Semi-structured interviews were conducted in situ with 33 participants (19 consumers and 14 stallholders) to discover their rationales for attending the festival, and their perspectives on ethical consumption. Transcripts were coded and thematically analysed, resulting in three themes reflecting varying degrees of public virtues (altruistic motivations) and private virtues (personal wellbeing): the quest for virtuous lifestyles through ethical consumption, the importance of co-production, and the challenges of putting ethical consumer projects like Slow Food into daily practice. The findings reveal the manner in which virtue ethics affects foodways and highlights the contingent and challenging nature of practising ethical eating. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Human skeletal muscle: transition between fast and slow fibre types.

    Science.gov (United States)

    Neunhäuserer, Daniel; Zebedin, Michaela; Obermoser, Magdalena; Moser, Gerhard; Tauber, Mark; Niebauer, Josef; Resch, Herbert; Galler, Stefan

    2011-05-01

    Human skeletal muscles consist of different fibre types: slow fibres (slow twitch or type I) containing the myosin heavy chain isoform (MHC)-I and fast fibres (fast twitch or type II) containing MHC-IIa (type IIA) or MHC-IId (type IID). The following order of decreasing kinetics is known: type IID > type IIA > type I. This order is especially based on the kinetics of stretch activation, which is the most discriminative property among fibre types. In this study we tested if hybrid fibres containing both MHC-IIa and MHC-I (type C fibres) provide a transition in kinetics between fast (type IIA) and slow fibres (type I). Our data of stretch activation kinetics suggest that type C fibres, with different ratios of MHC-IIa and MHC-I, do not provide a continuous transition. Instead, a specialized group of slow fibres, which we called "transition fibres", seems to provide a transition. Apart of their kinetics of stretch activation, which is most close to that of type IIA, the transition fibres are characterized by large cross-sectional areas and low maximal tensions. The molecular cause for the mechanical properties of the transition fibres is unknown. It is possible that the transition fibres contain an unknown slow MHC isoform, which cannot be separated by biochemical methods. Alternatively, or in addition, isoforms of myofibrillar proteins, other than MHC, and posttranslational modifications of myofibrillar proteins could play a role regarding the characteristics of the transition fibres.

  12. Fast and slow myosins as markers of muscle injury.

    Science.gov (United States)

    Guerrero, M; Guiu-Comadevall, M; Cadefau, J A; Parra, J; Balius, R; Estruch, A; Rodas, G; Bedini, J L; Cussó, R

    2008-07-01

    The diagnosis of muscular lesions suffered by athletes is usually made by clinical criteria combined with imaging of the lesion (ultrasonography and/or magnetic resonance) and blood tests to detect the presence of non-specific muscle markers. This study was undertaken to evaluate injury to fast and slow-twitch fibres using specific muscle markers for these fibres. Blood samples were obtained from 51 non-sports people and 38 sportsmen with skeletal muscle injury. Western blood analysis was performed to determine fast and slow myosin and creatine kinase (CK) levels. Skeletal muscle damage was diagnosed by physical examination, ultrasonography and magnetic resonance and biochemical markers. The imaging tests were found to be excellent for detecting and confirming grade II and III lesions. However, grade I lesions were often unconfirmed by these techniques. Grade I lesions have higher levels of fast myosin than slow myosin with a very small increase in CK levels. Grade II and III lesions have high values of both fast and slow myosin. The evaluation of fast and slow myosin in the blood 48 h after the lesion occurs is a useful aid for the detection of type I lesions in particular, since fast myosin is an exclusive skeletal muscle marker. The correct diagnosis of grade I lesions can prevent progression of the injury in athletes undergoing continual training sessions and competitions, thus aiding sports physicians in their decision making.

  13. Slow extraction control system of HIRFL-CSR

    International Nuclear Information System (INIS)

    Liu Wufeng; Qiao Weimin; Yuan Youjin; Mao Ruishi; Zhao Tiecheng

    2013-01-01

    For heavy-ion radiotherapy, HIRFL-CSR (Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring) needs a long term uniform ion beam extraction from HIRFL-CSR main ring to high energy beam transport line to meet the requirement of heavy-ion radiotherapy's ion beam. Slow extraction control system uses the synchronous signal of HIRFL-CSR control system's timing system to realize process control. When the synchronous event data of HIRFL-CSR control system's timing system trigger controlling and changing data (frequency value, tune value, voltage value), the waveform generator will generate waveform by frequency value, tune value and voltage value, and will amplify the generated waveform by power amplifier to electrostatic deflector to achieve RF-KO slow extraction. The synchronous event receiver of slow extraction system is designed by using FPGA and optical fiber interface to keep high transmission speed and anti-jamming. HIRFL-CSR's running for heavy-ion radiotherapy and ten thousand seconds long period slow extraction experiments show that slow extraction control system is workable and can meet the requirement of heavy-ion radiotherapy's ion beam. (authors)

  14. Late-type components of slow novae and symbiotic stars

    Energy Technology Data Exchange (ETDEWEB)

    Allen, D A [Anglo-Australian Observatory, Epping (Australia); Royal Observatory, Edinburgh (UK))

    1980-08-01

    It is argued that the various types of symbiotic stars and the slow novae are the same phenomena exhibiting a range of associated time-scales, the slow novae being of intermediate speed. Evidence is summarized showing that both types of object contain normal M giants or mira variables. This fact is at odds with currently fashionable single-star models for slow novae, according to which the M star is totally disrupted before the outburst. Spectral types of the late-type components are presented for nearly 80 symbiotic stars and slow novae, derived from 2 ..mu..m spectroscopy. It is found that both the intensity of the emission spectrum and the electron density of the gas are functions of the spectral type of the late-type star. Explanations for these correlations are given. On the assumption that the late-type components are normal giants, spectroscopic parallaxes are determined; credible distances are derived which indicate that the known symbiotic stars have been sampled as far afield as the Galactic Centre. Hydrogen shell flashes on a white dwarf accreting gas from the late-type components offer an attractive explanation of the phenomena of slow novae and symbiotic stars, and such models are discussed in the concluding section.

  15. Optimizing detection and analysis of slow waves in sleep EEG.

    Science.gov (United States)

    Mensen, Armand; Riedner, Brady; Tononi, Giulio

    2016-12-01

    Analysis of individual slow waves in EEG recording during sleep provides both greater sensitivity and specificity compared to spectral power measures. However, parameters for detection and analysis have not been widely explored and validated. We present a new, open-source, Matlab based, toolbox for the automatic detection and analysis of slow waves; with adjustable parameter settings, as well as manual correction and exploration of the results using a multi-faceted visualization tool. We explore a large search space of parameter settings for slow wave detection and measure their effects on a selection of outcome parameters. Every choice of parameter setting had some effect on at least one outcome parameter. In general, the largest effect sizes were found when choosing the EEG reference, type of canonical waveform, and amplitude thresholding. Previously published methods accurately detect large, global waves but are conservative and miss the detection of smaller amplitude, local slow waves. The toolbox has additional benefits in terms of speed, user-interface, and visualization options to compare and contrast slow waves. The exploration of parameter settings in the toolbox highlights the importance of careful selection of detection METHODS: The sensitivity and specificity of the automated detection can be improved by manually adding or deleting entire waves and or specific channels using the toolbox visualization functions. The toolbox standardizes the detection procedure, sets the stage for reliable results and comparisons and is easy to use without previous programming experience. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Control of recollection by slow gamma dominating mid-frequency gamma in hippocampus CA1

    Science.gov (United States)

    Dvorak, Dino; Radwan, Basma; Sparks, Fraser T.; Talbot, Zoe Nicole

    2018-01-01

    Behavior is used to assess memory and cognitive deficits in animals like Fmr1-null mice that model Fragile X Syndrome, but behavior is a proxy for unknown neural events that define cognitive variables like recollection. We identified an electrophysiological signature of recollection in mouse dorsal Cornu Ammonis 1 (CA1) hippocampus. During a shocked-place avoidance task, slow gamma (SG) (30–50 Hz) dominates mid-frequency gamma (MG) (70–90 Hz) oscillations 2–3 s before successful avoidance, but not failures. Wild-type (WT) but not Fmr1-null mice rapidly adapt to relocating the shock; concurrently, SG/MG maxima (SGdom) decrease in WT but not in cognitively inflexible Fmr1-null mice. During SGdom, putative pyramidal cell ensembles represent distant locations; during place avoidance, these are avoided places. During shock relocation, WT ensembles represent distant locations near the currently correct shock zone, but Fmr1-null ensembles represent the formerly correct zone. These findings indicate that recollection occurs when CA1 SG dominates MG and that accurate recollection of inappropriate memories explains Fmr1-null cognitive inflexibility. PMID:29346381

  17. The effect of the MgO buffer layer thickness on magnetic anisotropy in MgO/Fe/Cr/MgO buffer/MgO(001)

    Energy Technology Data Exchange (ETDEWEB)

    Kozioł-Rachwał, Anna, E-mail: a.koziolrachwal@aist.go.jp [National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); Nozaki, Takayuki; Zayets, Vadym; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji [National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); Suzuki, Yoshishige [National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)

    2016-08-28

    The relationship between the magnetic properties and MgO buffer layer thickness d was studied in epitaxial MgO/Fe(t)/Cr/MgO(d) layers grown on MgO(001) substrate in which the Fe thickness t ranged from 0.4 nm to 1.1 nm. For 0.4 nm ≤ t ≤ 0.7 nm, a non-monotonic coercivity dependence on the MgO buffer thickness was shown by perpendicular magneto-optic Kerr effect magnetometry. For thicker Fe films, an increase in the buffer layer thickness resulted in a spin reorientation transition from perpendicular to the in-plane magnetization direction. Possible origins of these unusual behaviors were discussed in terms of the suppression of carbon contamination at the Fe surface and changes in the magnetoelastic anisotropy in the system. These results illustrate a method to control magnetic anisotropy in MgO/Fe/Cr/MgO(d) via an appropriate choice of MgO buffer layer thickness d.

  18. Ultraviolet spectra of Mg in liquid helium

    International Nuclear Information System (INIS)

    Moriwaki, Y.; Morita, N.

    1999-01-01

    Emission and absorption spectra of Mg atoms implanted in liquid helium have been observed in the ultraviolet region. We have presented a model of exciplex formation of Mg-He 10 and found that this model is more suitable for understanding the dynamics in the 3s3p 1 P→3s 21 S transition than the bubble model. (orig.)

  19. AN ANOMALOUS COMPOSITION IN SLOW SOLAR WIND AS A SIGNATURE OF MAGNETIC RECONNECTION IN ITS SOURCE REGION

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, L.; Landi, E.; Lepri, S. T.; Kocher, M.; Zurbuchen, T. H.; Fisk, L. A.; Raines, J. M., E-mail: lzh@umich.edu [Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)

    2017-01-01

    In this paper, we study a subset of slow solar winds characterized by an anomalous charge state composition and ion temperatures compared to average solar wind distributions, and thus referred to as an “Outlier” wind. We find that although this wind is slower and denser than normal slow wind, it is accelerated from the same source regions (active regions and quiet-Sun regions) as the latter and its occurrence rate depends on the solar cycle. The defining property of the Outlier wind is that its charge state composition is the same as that of normal slow wind, with the only exception being a very large decrease in the abundance of fully charged species (He{sup 2+}, C{sup 6+}, N{sup 7+}, O{sup 8+}, Mg{sup 12+}), resulting in a significant depletion of the He and C element abundances. Based on these observations, we suggest three possible scenarios for the origin of this wind: (1) local magnetic waves preferentially accelerating non-fully stripped ions over fully stripped ions from a loop opened by reconnection; (2) depleted fully stripped ions already contained in the corona magnetic loops before they are opened up by reconnection; or (3) fully stripped ions depleted by Coulomb collision after magnetic reconnection in the solar corona. If any one of these three scenarios is confirmed, the Outlier wind represents a direct signature of slow wind release through magnetic reconnection.

  20. Anisotropic Mg Electrodeposition and Alloying with Ag-based Anodes from Non-Coordinating Mixed-Metal Borohydride Electrolytes for Mg Hybrid Batteries

    International Nuclear Information System (INIS)

    Wetzel, David J.; Malone, Marvin A.; Gewirth, Andrew A.; Nuzzo, Ralph G.

    2017-01-01

    A highly anisotropic electrodeposition was observed using the hybrid battery electrolyte Mg(BH 4 ) 2 with LiBH 4 in diglyme. At low overpotentials high aspect ratio platelet morphologies are observed with a strong fiber texture composed of a {10-10} and a {11-20} component, the first evidence of behavior of this kind in magnesium battery electrolytes. At high overpotentials the deposit aspect ratio is indistinguishable but the texture is shown to be primarily composed of a {11-20} fiber texture. The kinetic parameters relative to the relevant crystallographic faces are extracted from electron microscopy images and compared with the observed bulk rate extracted from the electrochemical data. The use of polycrystalline Ag foil substrates with little preferred orientation at the surface allowed highly polycrystalline nucleation at lower overpotentials than that of platinum, likely due to Ag alloying with Mg. Characterization using focused ion beam (FIB) cross-sections with Auger Electron Spectroscopy (AES) elemental analysis confirm that the deposits are primarily Mg although Mg‐Ag alloys of various compositions were observed. It is proposed that the orientation at slow rates of growth is due to the underlying kinetics of adatom diffusion on Mg and that higher rates diminish the phenomenon due to decreased time for adatom diffusion and instead are governed by the rates of adatom formation or more specifically the adatom vacancy formation on the different low-index planes of Mg.

  1. Simplified slow anti-coincidence circuit for Compton suppression systems

    International Nuclear Information System (INIS)

    Al-Azmi, Darwish

    2008-01-01

    Slow coincidence circuits for the anti-coincidence measurements have been considered for use in Compton suppression technique. The simplified version of the slow circuit has been found to be fast enough, satisfactory and allows an easy system setup, particularly with the advantage of the automatic threshold setting of the low-level discrimination. A well-type NaI detector as the main detector surrounded by plastic guard detector has been arranged to investigate the performance of the Compton suppression spectrometer using the simplified slow circuit. The system has been tested to observe the improvement in the energy spectra for medium to high-energy gamma-ray photons from terrestrial and environmental samples

  2. Role of biological membranes in slow-wave sleep.

    Science.gov (United States)

    Karnovsky, M L

    1991-02-01

    Two involvements of cellular membranes in slow-wave sleep (SWS) are discussed. In the first the endoplasmic reticulum (ER) is focussed upon, and in the second, the plasmalemma, where specific binding sites (receptors?) for promoters of slow-wave sleep are believed to be located. The study concerning the ER focuses on an enzyme in the brain, glucose-6-phosphatase, which, although present at low levels, manifests greatly increased activity during SWS compared to the waking state. The work on the plasmalemma has to do with the specific binding of muramyl peptides, inducers of slow-wave sleep, to various cells, and membrane preparations of various sorts, including those from brain tissue. Such cells as macrophages from mice, B-lymphocytes from human blood, and cells from a cell line (C-6 glioma) have been examined in this context.

  3. Modeling fast and slow earthquakes at various scales.

    Science.gov (United States)

    Ide, Satoshi

    2014-01-01

    Earthquake sources represent dynamic rupture within rocky materials at depth and often can be modeled as propagating shear slip controlled by friction laws. These laws provide boundary conditions on fault planes embedded in elastic media. Recent developments in observation networks, laboratory experiments, and methods of data analysis have expanded our knowledge of the physics of earthquakes. Newly discovered slow earthquakes are qualitatively different phenomena from ordinary fast earthquakes and provide independent information on slow deformation at depth. Many numerical simulations have been carried out to model both fast and slow earthquakes, but problems remain, especially with scaling laws. Some mechanisms are required to explain the power-law nature of earthquake rupture and the lack of characteristic length. Conceptual models that include a hierarchical structure over a wide range of scales would be helpful for characterizing diverse behavior in different seismic regions and for improving probabilistic forecasts of earthquakes.

  4. Enhancing physics demos using iPhone slow motion

    Science.gov (United States)

    Lincoln, James

    2017-12-01

    Slow motion video enhances our ability to perceive and experience the physical world. This can help students and teachers especially in cases of fast moving objects or detailed events that happen too quickly for the eye to follow. As often as possible, demonstrations should be performed by the students themselves and luckily many of them will already have this technology in their pockets. The "S" series of iPhone has the slow motion video feature standard, which also includes simultaneous sound recording (somewhat unusual among slow motion cameras). In this article I share some of my experiences using this feature and provide advice on how to successfully use this technology in the classroom.

  5. The condition for classical slow rolling in new inflation

    International Nuclear Information System (INIS)

    Sasaki, Misao; Nambu, Yasusada; Nakao, Ken-ichi.

    1988-02-01

    By means of the stochastic description of inflation, we investigate the dynamics of a fixed comoving domain in a continuously inflating universe on the global scale, both analytically and numerically. A particular attention is paid to the condition for a domain to enter the classical slow rolling phase. New inflationary universe models with the potential form, V(φ) ∼ V 0 - cφ 2n at φ ∼ 0 are considered. The critical value of the scalar field beyond which the field slowly rolls down the potential hill is estimated. We find, for all models under consideration, the condition for classical slow rolling is a sufficient condition for the expected amplitude of density perturbations to be smaller than unity. In other words, the density perturbation amplitude at the later Friedmann stage is always smaller than unity if the universe experienced the classical slow roll-over phase. (author)

  6. Study of Dynamic Characteristics of Slow-Changing Process

    Directory of Open Access Journals (Sweden)

    Yinong Li

    2000-01-01

    Full Text Available A vibration system with slow-changing parameters is a typical nonlinear system. Such systems often occur in the working and controlled process of some intelligent structures when vibration and deformation exist synchronously. In this paper, a system with slow-changing stiffness, damping and mass is analyzed in an intelligent structure. The relationship between the amplitude and the frequency of the system is studied, and its dynamic characteristic is also discussed. Finally, a piecewise linear method is developed on the basis of the asymptotic method. The simulation and the experiment show that a suitable slow-changing stiffness can restrain the amplitude of the system when the system passes through the resonant region.

  7. Table incremental slow injection CE-CT in lung cancer

    International Nuclear Information System (INIS)

    Yoshida, Shoji; Maeda, Tomoho; Morita, Masaru

    1988-01-01

    The purpose of this study is to evaluate tumor enhancement in lung cancer under the table incremental study with slow injection of contrast media. The early serial 8 sliced images during the slow injection (1.5 ml/sec) of contrant media were obtained. Following the early images, delayed 8 same sliced images were taken in 2 minutes later. Chacteristic enhanced patterns of the primary cancer and metastatic mediastinal lymphnode were recognized in this study. Enhancement of the primary lesion was classified in 4 patterns, irregular geographic pattern, heterogeneous pattern, homogeneous pattern and rim-enhanced pattern. In mediastinal metastatic lymphadenopathy, three enhanced patterns were obtained, heterogeneous, homogeneous and ring enhanced pattern. Some characteristic enhancement patterns according to the histopathological finding of the lung cancer were obtained. With using this incremental slow injection CE-CT, precise information about the relationship between lung cancer and adjacent mediastinal structure, and obvious staining patterns of the tumor and mediastinal lymphnode were recognized. (author)

  8. The condition for classical slow rolling in new inflation

    International Nuclear Information System (INIS)

    Sasaki, Misao; Nambu, Yasusada; Nakao, Ken-ichi

    1988-01-01

    By means of the stochastic description of inflation we investigate the dynamics of a fixed comoving domain in a continuously inflating universe on a global scale, both analytically and numerically. Particular attention is paid to the condition for a domain to enter the classical slow rolling phase. New inflationary universe models with the potential form V(φ) ≅ V 0 -cφ 2n at φ ≅ 0 are considered. The critical value of the scalar field beyond which the field slowly rolls down the potential hill is estimated. We find that for all models under consideration, the condition for classical slow rolling is a sufficient condition for the expected amplitude of density perturbations to be smaller than unity. In other words, the density perturbation amplitude at the later Friedmann stage is always smaller than unity if the universe experienced the classical slow roll-over phase. (orig.)

  9. Slow dynamics in translation-invariant quantum lattice models

    Science.gov (United States)

    Michailidis, Alexios A.; Žnidarič, Marko; Medvedyeva, Mariya; Abanin, Dmitry A.; Prosen, Tomaž; Papić, Z.

    2018-03-01

    Many-body quantum systems typically display fast dynamics and ballistic spreading of information. Here we address the open problem of how slow the dynamics can be after a generic breaking of integrability by local interactions. We develop a method based on degenerate perturbation theory that reveals slow dynamical regimes and delocalization processes in general translation invariant models, along with accurate estimates of their delocalization time scales. Our results shed light on the fundamental questions of the robustness of quantum integrable systems and the possibility of many-body localization without disorder. As an example, we construct a large class of one-dimensional lattice models where, despite the absence of asymptotic localization, the transient dynamics is exceptionally slow, i.e., the dynamics is indistinguishable from that of many-body localized systems for the system sizes and time scales accessible in experiments and numerical simulations.

  10. Neurogenetics of slow axonal transport: from cells to animals.

    Science.gov (United States)

    Sadananda, Aparna; Ray, Krishanu

    2012-09-01

    Slow axonal transport is a multivariate phenomenon implicated in several neurodegenerative disorders. Recent reports have unraveled the molecular basis of the transport of certain slow component proteins, such as the neurofilament subunits, tubulin, and certain soluble enzymes such as Ca(2+)/calmodulin-dependent protein kinase IIa (CaM kinase IIa), etc., in tissue cultured neurons. In addition, genetic analyses also implicate microtubule-dependent motors and other housekeeping proteins in this process. However, the biological relevance of this phenomenon is not so well understood. Here, the authors have discussed the possibility of adopting neurogenetic analyses in multiple model organisms to correlate molecular level measurements of the slow transport phenomenon to animal behavior, thus facilitating the investigation of its biological efficacy.

  11. The Slow Control System of the Auger Fluorescence Detectors

    Science.gov (United States)

    Barenthien, N.; Bethge, C.; Daumiller, K.; Gemmeke, H.; Kampert, K.-H.; Wiebusch, C.

    2003-07-01

    The fluorescence detector (FD) of the Pierre Auger experiment [1] comprises 24 telescopes that will be situated in 4 remote buildings in the Pampa Amarilla. It is planned to run the fluorescence detectors in absence of operators on site. Therefore, the main task of the Slow Control System (SCS) is to ensure a secure remote operation of the FD system. The Slow Control System works autonomously and continuously monitors those parameters which may disturb a secure operation. Commands from the data-acquisition system or the remote operator are accepted only if they do not violate safety rules that depend on the actual experimental conditions (e.g. high-voltage, wind-sp eed, light, etc.). In case of malfunctions (power failure, communication breakdown, ...) the SCS performs an orderly shutdown and subsequent startup of the fluorescence detector system. The concept and the implementation of the Slow Control System are presented.

  12. Mutually-modulated cross-gain modulation and slow light

    International Nuclear Information System (INIS)

    Sternklar, Shmuel; Sarid, Eyal; Wart, Maxim; Granot, Er'el

    2010-01-01

    The interaction of pump and Stokes light in a Brillouin medium, where both beams are modulated, can be utilized for controlling the group velocity of the amplified Stokes (or depleted pump). The dependence of the group velocity for this mutually-modulated cross-gain modulation (MMXGM) technique on the Brillouin gain parameter is studied. A sharp transition to slow light occurs in the G 1 α/β≈1 regime, where G 1 is the Brillouin gain parameter, and α and β are the pump and Stokes modulation indices, respectively. A comparison of MMXGM slow light to the Brillouin dispersion-based slow-light technique reveals the fundamental differences between them. The formation of higher harmonics of the modulation frequency is also discussed. The theoretical predictions are experimentally corroborated and potential applications in fiber-based sensing and interferometry are discussed

  13. Slow Orbit Feedback at the ALS Using Matlab

    International Nuclear Information System (INIS)

    Portmann, G.

    1999-01-01

    The third generation Advanced Light Source (ALS) produces extremely bright and finely focused photon beams using undulatory, wigglers, and bend magnets. In order to position the photon beams accurately, a slow global orbit feedback system has been developed. The dominant causes of orbit motion at the ALS are temperature variation and insertion device motion. This type of motion can be removed using slow global orbit feedback with a data rate of a few Hertz. The remaining orbit motion in the ALS is only 1-3 micron rms. Slow orbit feedback does not require high computational throughput. At the ALS, the global orbit feedback algorithm, based on the singular valued decomposition method, is coded in MATLAB and runs on a control room workstation. Using the MATLAB environment to develop, test, and run the storage ring control algorithms has proven to be a fast and efficient way to operate the ALS

  14. Hydrothermal Formation of the Head-to-Head Coalesced Szaibelyite MgBO2(OH Nanowires

    Directory of Open Access Journals (Sweden)

    Zhu Wancheng

    2009-01-01

    Full Text Available Abstract The significant effect of the feeding mode on the morphology and size distribution of the hydrothermal synthesized MgBO2(OH is investigated, which indicates that, slow dropping rate (0.5 drop s−1 and small droplet size (0.02 mL d−1 of the dropwise added NaOH solution are favorable for promoting the one-dimensional (1D preferential growth and thus enlarging the aspect ratio of the 1D MgBO2(OH nanostructures. The joint effect of the low concentration of the reactants and feeding mode on the hydrothermal product results in the head-to-head coalesced MgBO2(OH nanowires with a length of 0.5–9.0 μm, a diameter of 20–70 nm, and an aspect ratio of 20–300 in absence of any capping reagents/surfactants or seeds.

  15. Room-temperature ferromagnetism observed in C-/N-/O-implanted MgO single crystals

    Science.gov (United States)

    Li, Qiang; Ye, Bonian; Hao, Yingping; Liu, Jiandang; Zhang, Jie; Zhang, Lijuan; Kong, Wei; Weng, Huimin; Ye, Bangjiao

    2013-01-01

    MgO single crystals were implanted with 70 keV C/N/O ions at room temperature with respective doses of 2 × 1016 and 2 × 1017 ions/cm2. All samples with high-dose implantation showed room temperature hysteresis in magnetization loops. Magnetization and slow positron annihilation measurements confirmed that room temperature ferromagnetism in O-implanted samples was attributed to the presence of Mg vacancies. Furthermore, the introduction of C or N played more effective role in ferromagnetic performance than Mg vacancies. Moreover, the magnetic moment possibly occurred from the localized wave function of unpaired electrons and the exchange interaction formed a long-range magnetic order.

  16. Computation of saddle-type slow manifolds using iterative methods

    DEFF Research Database (Denmark)

    Kristiansen, Kristian Uldall

    2015-01-01

    with respect to , appropriate estimates are directly attainable using the method of this paper. The method is applied to several examples, including a model for a pair of neurons coupled by reciprocal inhibition with two slow and two fast variables, and the computation of homoclinic connections in the Fitz......This paper presents an alternative approach for the computation of trajectory segments on slow manifolds of saddle type. This approach is based on iterative methods rather than collocation-type methods. Compared to collocation methods, which require mesh refinements to ensure uniform convergence...

  17. Experimental studies of heavy-ion slowing down in matter

    International Nuclear Information System (INIS)

    Geissel, H.; Weick, H.; Scheidenberger, C.; Bimbot, R.; Gardes, D.

    2002-08-01

    Measurements of heavy-ion slowing down in matter differ in many aspects from experiments with light particles like protons and α-particles. An overview of the special experimental requirements, methods, data analysis and interpretation is presented for heavy-ion stopping powers, energy- and angular-straggling and ranges in the energy domain from keV/u up to GeV/u. Characteristic experimental results are presented and compared with theory and semiempirical predictions. New applications are outlined, which represent a challenge to continuously improve the knowledge of heavy-ion slowing down. (orig.)

  18. Low, slow, small target recognition based on spatial vision network

    Science.gov (United States)

    Cheng, Zhao; Guo, Pei; Qi, Xin

    2018-03-01

    Traditional photoelectric monitoring is monitored using a large number of identical cameras. In order to ensure the full coverage of the monitoring area, this monitoring method uses more cameras, which leads to more monitoring and repetition areas, and higher costs, resulting in more waste. In order to reduce the monitoring cost and solve the difficult problem of finding, identifying and tracking a low altitude, slow speed and small target, this paper presents spatial vision network for low-slow-small targets recognition. Based on camera imaging principle and monitoring model, spatial vision network is modeled and optimized. Simulation experiment results demonstrate that the proposed method has good performance.

  19. Pulsed neutron method for diffusion, slowing down, and reactivity measurements

    International Nuclear Information System (INIS)

    Sjoestrand, N.G.

    1985-01-01

    An outline is given on the principles of the pulsed neutron method for the determination of thermal neutron diffusion parameters, for slowing-down time measurements, and for reactivity determinations. The historical development is sketched from the breakthrough in the middle of the nineteen fifties and the usefulness and limitations of the method are discussed. The importance for the present understanding of neutron slowing-down, thermalization and diffusion are point out. Examples are given of its recent use for e.g. absorption cross section measurements and for the study of the properties of heterogeneous systems

  20. Solution of neutron slowing down equation including multiple inelastic scattering

    International Nuclear Information System (INIS)

    El-Wakil, S.A.; Saad, A.E.

    1977-01-01

    The present work is devoted the presentation of an analytical method for the calculation of elastically and inelastically slowed down neutrons in an infinite non absorbing homogeneous medium. On the basis of the Central limit theory (CLT) and the integral transform technique the slowing down equation including inelastic scattering in terms of the Green function of elastic scattering is solved. The Green function is decomposed according to the number of collisions. A formula for the flux at any lethargy O (u) after any number of collisions is derived. An equation for the asymptotic flux is also obtained

  1. Wide-band slow-wave systems simulation and applications

    CERN Document Server

    Staras, Stanislovas

    2012-01-01

    The field of electromagnetics has seen considerable advances in recent years, based on the wide applications of numerical methods for investigating electromagnetic fields, microwaves, and other devices. Wide-Band Slow-Wave Systems: Simulation and Applications presents new technical solutions and research results for the analysis, synthesis, and design of slow-wave structures for modern electronic devices with super-wide pass-bands. It makes available, for the first time in English, significant research from the past 20 years that was previously published only in Russian and Lithuanian. The aut

  2. Efficiency evaluation of slow extraction from the synchrotron

    International Nuclear Information System (INIS)

    Kazarinov, N.Yu.; Mikhajlov, V.A.

    1986-01-01

    Analytical calculation of slow extraction of the beam out of the JINR synchrotron is made. The formulae for evaluation of the sextupole amplitudes and phases, quadrupole lens gradient range are obtained, the connection with circulated and extracted beam parameters is shown. The formulae for calculating optimal position of the septum-magnet or electrostatic septum are presented. On this basis the formula for estimating the efficiency of beam slow extraction out of the synchrotron is obtained under assumption that in the septum region during the extraction a quasistationary distribution of the beam density occurs

  3. Consumption of polyphenol plants may slow aging and associated diseases.

    Science.gov (United States)

    Uysal, Utku; Seremet, Sila; Lamping, Jeffrey W; Adams, Jerome M; Liu, Deede Y; Swerdlow, Russell H; Aires, Daniel J

    2013-01-01

    Slowing aging is a widely shared goal. Plant-derived polyphenols, which are found in commonly consumed food plants such as tea, cocoa, blueberry and grape, have been proposed to have many health benefits, including slowing aging. In-vivo studies have demonstrated the lifespan-extending ability of six polyphenol-containing plants. These include five widely consumed foods (tea, blueberry, cocoa, apple, pomegranate) and a flower commonly used as a folk medicine (betony). These and multiple other plant polyphenols have been shown to have beneficial effects on aging-associated changes across a variety of organisms from worm and fly to rodent and human.

  4. Changes in cognition, arm function and lower body function after Slow-Release Fampridine treatment

    DEFF Research Database (Denmark)

    Jensen, Henrik Boye; Ravnborg, Mads; Mamoei, Sepehr

    2014-01-01

    OBJECTIVE: We aimed to evaluate the effect of slow-release (SR) Fampridine on multiple outcome measures reflecting different domains, and to compare the responsiveness of the Six Spot Step Test (SSST) and the Timed 25 Foot Walk (T25FW). METHODS: For this study 108 participants were included. On day...... 0 they were tested with the T25FW, the SSST, the 9-Hole Peg Test (9-HPT), the 5 Times Sit-To-Stand test (5-STS) and the Symbol Digit Modalities Test (SDMT). Four weeks of treatment with SR Fampridine 10 mg BID was commenced. Participants were tested again after 26-28 days of treatment. RESULTS: Mean...... and cognition. Furthermore, the SSST is more responsive to the effect of SR Fampridine than is the T25FW. ClinicalTrials.gov identifier: NCT01656148....

  5. THE INFLUENCE OF SLOW THAWING ON EVOLUTION OF SOME BIOCHEMICAL COMPOUNDS IN FROZEN FISHES

    Directory of Open Access Journals (Sweden)

    Marcel AVRAMIUC

    2017-06-01

    Full Text Available The aim of this work was to study the evolution of pH, amino nitrogen and nitrogen from aminoacids in four fish species, during 48 hours of slow thawing, in order to assess the fish spoilage speed in these keeping conditions. The biological material was represented by frozen fishes (carp, catfish, mackerel and hake which were subjected to slow thawing at room temperature (+20..+22°C, by analysing, at certain time intervals, pH, amino nitrogen - AN (mg %, and nitrogen from aminoacids - NAA (g %. The pH was determined with a digital pH-meter type Hanna, and the nitrogen from aminoacids according to Sörensen method. The amino nitrogen was determined by the difference between the nitrogen content of volatile bases and the nitrogen content of the ammonia and primary amines. As compared to frozen samples, both pH and the amino nitrogen values of all fish samples showed constant and significant increases up to the end of the analyzed period, while the nitrogen from aminoacids only in the first 30 hours of thawing. The amino nitrogen and the nitrogen from amino acids values have indicated the highest spoilage speed in catfish and hake, and the least speed in mackerel.

  6. Optical absorption and thermoluminescence in Mg O, Mg O:Ni and Mg O:Li irradiated at room temperature

    International Nuclear Information System (INIS)

    Delgado, L.

    1984-01-01

    Optical absorption and thermoluminescence (TL) studies in Mg O, Mg O:Ni and Mg O:Li irradiated at room temperature are presented. In pure Mg O the thermal annihilation of Fe3+ by recombination with thermally released electrons at ∼ 90 and 175 degree centigree and the V center annealing by hole release up to 100 degree centigree cause the observed glow peaks at these temperatures. The TL excitation spectrum shows two maxima at 245 nm (electron center) and 288 nm (Fe3+). In Mg O:Ni X irradiation induces Fe 2 + →- Fe 3 + and Ni 2 + → Ni 3 + oxidations. Two TL emission bands centered at 110 degree centigree (red) and 80 o C (green) are assigned to electron release and their recombination at Fe 3 + and Ni 3 + respectively. In Mg O:Li two TL emission bands, one blue (430 nm) and the other red (730 nm) with excitation maxima at 245 nm (electron center) and 200 nm (hole center) respectively are observed. No V-center formation was detected in both Ni and Li doped samples. (Author) 42 refs

  7. Mg2BIV: Narrow Bandgap Thermoelectric Semiconductors

    Science.gov (United States)

    Kim, Il-Ho

    2018-05-01

    Thermoelectric materials can convert thermal energy directly into electric energy and vice versa. The electricity generation from waste heat via thermoelectric devices can be considered as a new energy source. For instance, automotive exhaust gas and all industrial processes generate an enormous amount of waste heat that can be converted to electricity by using thermoelectric devices. Magnesium compound Mg2BIV (BIV = Si, Ge or Sn) has a favorable combination of physical and chemical properties and can be a good base for the development of new efficient thermoelectrics. Because they possess similar properties to those of group BIV elemental semiconductors, they have been recognized as good candidates for thermoelectric applications. Mg2Si, Mg2Ge and Mg2Sn with an antifluorite structure are narrow bandgap semiconductors with indirect band gaps of 0.77 eV, 0.74 eV, and 0.35 eV, respectively. Mg2BIV has been recognized as a promising material for thermoelectric energy conversion at temperatures ranging from 500 K to 800 K. Compared to other thermoelectric materials operating in the similar temperature range, such as PbTe and filled skutterudites, the important aspects of Mg2BIV are non-toxic and earth-abundant elements. Based on classical thermoelectric theory, the material factor β ( m* / m e)3/2μκ L -1 can be utilized as the criterion for thermoelectric material selection, where m* is the density-of-states effective mass, me is the mass of an electron, μ is the carrier mobility, and κL is the lattice thermal conductivity. The β for magnesium silicides is 14, which is very high compared to 0.8 for iron silicides, 1.4 for manganese silicides, and 2.6 for silicon-germanium alloys. In this paper, basic phenomena of thermoelectricity and transport parameters for thermoelectric materials were briefly introduced, and thermoelectric properties of Mg2BIV synthesized by using a solid-state reaction were reviewed. In addition, various Mg2BIV compounds were discussed

  8. Elimination of Schistosoma mansoni in infected mice by slow release of artemisone

    Directory of Open Access Journals (Sweden)

    Daniel Gold

    2017-08-01

    Full Text Available The current treatment of schistosomiasis is based on the anti-helminthic drug praziquantel (PZQ. PZQ affects only the adult stages of schistosomes. In addition, resistance to PZQ is emerging. We suggest a drug, which could serve as a potential alternative or complement to PZQ, and as a means of treating infections at earlier, pre-granuloma stage. Derivatives of the peroxidic antimalarial drug artemisinin have been indicated as alternatives, because both plasmodia and schistosomes are blood-feeding parasites. The mechanism of action of artemisinins is related to oxidative effects of the artemisinins on intracellular reductants leading to formation of cytotoxic reactive oxygen species. We used artemisone, which has improved pharmacokinetics and anti-plasmodial activity, and reduced toxicity compared to other artemisinins in clinical use against malaria. We infected adult mice by subcutaneous injection of S. mansoni cercariae (about 200 and treated them at various times post infection by the following methods: i. artemisone suspension administered by gavage (400–450 mg/kg; ii. subcutaneous injection of a gel containing a known concentration of artemisone (115–120 mg/kg; iii. subcutaneous insertion of the drug incorporated in a solid polymer (56–60 mg/kg; iv. intraperitoneal injection of the drug solubilized in DMSO (115–120 mg/kg. Drug administration in polymers was performed to enable slow release of the artemisone that was verified in vivo and in vitro bioassays using drug-sensitive malaria parasites. We found superior strong anti-schistosome effects up to a total reduction of worm number, mainly following repetitive treatments with the drug absorbed in the polymers (73.1% and 95.9% reduction in mice treated with artemisone in gel 7 and 14, and 21, 28 and 35 days post infection, respectively. The results indicate that artemisone has a potent anti-schistosome activity. Its main importance in this context is its effectiveness in

  9. Microstructure and mechanical properties of an Al–Mg alloy solidified under high pressures

    International Nuclear Information System (INIS)

    Jie, J.C.; Zou, C.M.; Brosh, E.; Wang, H.W.; Wei, Z.J.; Li, T.J.

    2013-01-01

    Highlights: •Al–42.2Mg alloy was solidified under pressures of 1, 2, and 3 GPa and the microstructure analyzed. •A thermodynamic calculation of the Al–Mg phase diagram at high pressures was performed. •The phase content changes from predominantly γ-Al 12 Mg 17 at 1 GPa to FCC solid solution at 3 GPa. •The β-Al 3 Mg 2 is predicted to remain stable at low temperatures but is not observed. •The alloy solidified at high pressure has remarkably enhanced ultimate tensile strength. -- Abstract: Phase formation, the microstructure and its evolution, and the mechanical properties of an Al–42.2 at.% Mg alloy solidified under high pressures were investigated. After solidification at pressures of 1 GPa and 2 GPa, the main phase is the γ phase, richer in Al than in equilibrium condition. When the pressure is further increased to 3 GPa, the main phase is the supersaturated Al(Mg) solid solution with Mg solubility up to 41.6 at.%. Unlike in similar alloys solidified at ambient pressure, the β phase does not appear. Calculated high-pressure phase diagrams of the Al–Mg system show that although the stability range of the β phase is diminished with pressure, it is still thermodynamically stable at room temperature. Hence, the disappearance of the β phase is interpreted as kinetic suppression, due to the slow diffusion rate at high pressures, which inhibits solid–solid reactions. The Al–42.2 at.% Mg alloy solidified under 3 GPa has remarkably enhanced ultimate tensile strength compared to the alloy solidified under normal atmospheric pressure

  10. Observing and modeling the spectrum of a slow slip event: Constraints on the scaling of slow slip and tremor

    Science.gov (United States)

    Hawthorne, J. C.; Bartlow, N. M.; Ghosh, A.

    2017-12-01

    We estimate the normalized moment rate spectrum of a slow slip event in Cascadia and then attempt to reproduce it. Our goal is to further assess whether a single physical mechanism could govern slow slip and tremor events, with durations that span 6 orders of magnitude, so we construct the spectrum by parameterizing a large slow slip event as the sum of a number of subevents with various durations. The spectrum estimate uses data from three sources: the GPS-based slip inversion of Bartlow et al (2011), PBO borehole strain measurements, and beamforming-based tremor moment estimates of Ghosh et al (2009). We find that at periods shorter than 1 day, the moment rate power spectrum decays as frequencyn, where n is between 0.7 and 1.4 when measured from strain and between 1.2 and 1.4 when inferred from tremor. The spectrum appears roughly flat at periods of 1 to 10 days, as both the 1-day-period strain and tremor data and the 6-day-period slip inversion data imply a moment rate power of 0.02 times the the total moment squared. We demonstrate one way to reproduce this spectrum: by constructing the large-scale slow slip event as the sum of a series of subevents. The shortest of these subevents could be interpreted as VLFEs or even LFEs, while longer subevents might represent the aseismic slip that drives rapid tremor reverals, streaks, or rapid tremor migrations. We pick the subevent magnitudes from a Gutenberg-Richter distribution and place the events randomly throughout a 30-day interval. Then we assign each subevent a duration that scales with its moment to a specified power. Finally, we create a moment rate function for each subevent and sum all of the moment rates. We compute the summed slow slip moment rate spectra with two approaches: a time-domain numerical computation and a frequency-domain analytical summation. Several sets of subevent parameters can allow the constructed slow slip event to match the observed spectrum. One allowable set of parameters is of

  11. Superconductivity in MgB{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Muranaka, Takahiro; Akimitsu, Jun [Aoyama Gakuin Univ., Kanagawa (Japan). Dept. of Physics and Mathematics

    2011-07-01

    We review superconductivity in MgB{sub 2} in terms of crystal and electronic structure, electron-phonon coupling, two-gap superconductivity and application. Finally, we introduce the development of new superconducting materials in related compounds. (orig.)

  12. Additive Manufacturing of Magnesium (Mg) Alloys

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed work is to investigate additive manufacturing techniques for Mg alloys.  It will leverage off research being conducted at University of Florida and...

  13. Textile slow-release systems with medical applications

    NARCIS (Netherlands)

    ten Breteler, M.R.; Nierstrasz, Vincent; Warmoeskerken, Marinus

    2002-01-01

    In the development of medical drug delivery systems, attention has been increasingly focused on slow- or controlled delivery systems in order to achieve an optimal therapeutic effect. Since the administration of drugs often requires a defined or minimum effective dosage in the human body, more

  14. Delineating psychomotor slowing from reduced processing speed in schizophrenia

    NARCIS (Netherlands)

    Morrens, M.; Hulstijn, W.; Matton, C.; Madani, Y.; Bouwel, L. van; Peuskens, J.; Sabbe, B.G.C.

    2008-01-01

    Introduction. Psychomotor slowing is an intrinsic feature of schizophrenia that is poorly delineated from generally reduced processing speed. Although the Symbol Digit Substitution Test (SDST) is widely used to assess psychomotor speed, the task also taps several higher-order cognitive processes.

  15. Investigating the critical slowing down of QCD simulations

    International Nuclear Information System (INIS)

    Schaefer, Stefan

    2009-12-01

    Simulations of QCD are known to suffer from serious critical slowing down towards the continuum limit. This is particularly prominent in the topological charge. We investigate the severeness of the problem in the range of lattice spacings used in contemporary simulations and propose a method to give more reliable error estimates. (orig.)

  16. Passive integrated circuits utilizing slow light in photonic crystal waveguides

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Têtu, Amélie; Yang, Lirong

    2006-01-01

    We report thorough investigations of photonic crystal waveguide properties in the slow light regime. The transmission and the group index near the cutoff wavelengths oscillate in phase in close analogy with the ID photonic crystal behavior. The influence of having a finite number of periods...

  17. Slow Light by Two-Dimensional Photonic Crystal Waveguides

    International Nuclear Information System (INIS)

    Chao, Zhang; Yan, Huang; Xiao-Yu, Mao; Kai-Yu, Cui; Yi-Dong, Huang; Wei, Zhang; Jiang-De, Peng

    2009-01-01

    A simple and effective way to measure the group velocity of photonic crystal waveguides (PCWGs) is developed by using a fiber Mach–Zehnder interferometer. A PCWG with perfect air-bridge structure is fabricated and slow light with group velocity slower than c/80 is demonstrated. (fundamental areas of phenomenology (including applications))

  18. Reduction in slow intercompartmental clearance of urea during dialysis

    International Nuclear Information System (INIS)

    Bowsher, D.J.; Krejcie, T.C.; Avram, M.J.; Chow, M.J.; Del Greco, F.; Atkinson, A.J. Jr.

    1985-01-01

    The kinetics of urea and inulin were analyzed in five anesthetized dogs during sequential 2-hour periods before, during, and after hemodialysis. The distribution of both compounds after simultaneous intravenous injection was characterized by three-compartment models, and the total volumes of urea (0.66 +/- 0.05 L/kg) and inulin (0.19 +/- 0.01 L/kg) distribution were similar to expected values for total body water and extravascular space, respectively. Intercompartmental clearances calculated before dialysis were used to estimate blood flows to the fast and slow equilibrating compartments. In agreement with previous results, the sum of these flows was similar to cardiac output, averaging 101% of cardiac output measured before dialysis (range 72% to 135%). Dialysis was accompanied by reductions in the slow intercompartmental clearances of urea (81%) and inulin (47%), which reflected a 90% attenuation in blood flow supplying the slow equilibrating compartments. This was estimated to result in a 10% average reduction in the efficiency with which urea was removed by dialysis (range 2.0% to 16.4%). Mean arterial pressure fell by less than 5% during dialysis, but total peripheral resistance increased by 47% and cardiac output fell by 35%. In the postdialysis period, total peripheral resistance and cardiac output returned toward predialysis values, but blood flow to the slow equilibrating peripheral compartment was still reduced by 80%. These changes parallel activation of the renin-angiotensin system, but further studies are required to establish causality

  19. Spatial ability of slow learners based on Hubert Maier theory

    Science.gov (United States)

    Permatasari, I.; Pramudya, I.; Kusmayadi, T. A.

    2018-03-01

    Slow learners are children who have low learning achievement (under the average of normal children) in one or all of the academic field, but they are not classified as a mentally retarded children. Spatial ability developed according to age and level of knowledge possessed, both from the neighborhood and formal education. Analyzing the spatial ability of students is important for teachers, as an effort to improve the quality of learning for slow learners. Especially on the implementation of inclusion school which is developing in Indonesia. This research used a qualitative method and involved slow learner students as the subject. Based on the data analysis it was found the spatial ability of slow learners, there were: spatial perception, students were able to describe the other shape of object when its position changed; spatial visualisation, students were able to describe the materials that construct an object; mental rotation, students cannot describe the object being rotated; spatial relation, students cannot describe the relations of same objects; spatial orientation, students were able to describe object from the others perspective.

  20. Optical signal processing using slow and fast light technologies

    DEFF Research Database (Denmark)

    Capmany, J.; Sales, Salvador; Xue, Weiqi

    2009-01-01

    We review the theory of slow and fat light effects due to coherent population oscillations in semiconductor waveguides, which can be potentially applied in microwave photonic systems as a RF phase shifters. In order to satisfy the application requirement of 360 degrees RF phase shift at different...

  1. First Observation of the Slow Dragonet Callionymus aagilis Fricke ...

    African Journals Online (AJOL)

    The slow dragonet is a rare marine species of the family Callionymidae, and is endemic to Reunion and Mauritius and possibly the other Mascarene Islands. It is grey in colour with small round white spots aligned on the flanks and a honeycomb pattern on the cheeks and the snout (Fig. 1a-c). The apices of the first dorsal ...

  2. One Size Fits All? Slow Cortical Potentials Neurofeedback: A Review

    Science.gov (United States)

    Mayer, Kerstin; Wyckoff, Sarah N.; Strehl, Ute

    2013-01-01

    Objective: The intent of this manuscript was to review all published studies on slow cortical potentials (SCP) neurofeedback for the treatment of ADHD, with emphasis on neurophysiological rationale, study design, protocol, outcomes, and limitations. Method: For review, PubMed, MEDLINE, ERIC, and Google Scholar searches identified six studies and…

  3. Group-index limitations in slow-light photonic crystals

    DEFF Research Database (Denmark)

    Grgic, Jure; Pedersen, Jesper Goor; Xiao, Sanshui

    2010-01-01

    radiation, and in-plane leakage. Often, the different mechanisms are playing in concert, leading to attenuation and scattering of electromagnetic modes. The very same broadening mechanisms also limit the attainable slow-down which we mimic by including a small imaginary part to the otherwise real...

  4. Slow Manifold and Hannay Angle in the Spinning Top

    Science.gov (United States)

    Berry, M. V.; Shukla, P.

    2011-01-01

    The spin of a top can be regarded as a fast variable, coupled to the motion of the axis which is slow. In pure precession, the rotation of the axis round a cone (without nutation), can be considered as the result of a reaction from the fast spin. The resulting restriction of the total state space of the top is an illustrative example, at…

  5. Slow light in quantum dot photonic crystal waveguides

    DEFF Research Database (Denmark)

    Nielsen, Torben Roland; Lavrinenko, Andrei; Mørk, Jesper

    2009-01-01

    A theoretical analysis of pulse propagation in a semiconductor quantum dot photonic crystal waveguide in the regime of electromagnetically induced transparency is presented. The slow light mechanism considered here is based on both material and waveguide dispersion. The group index n...

  6. Slow light based on material and waveguide dispersion

    DEFF Research Database (Denmark)

    Nielsen, Torben Roland; Lavrinenko, Andrei; Mørk, Jesper

    2009-01-01

    We study slow light pulse propagation in a photonic crystal structure consisting of a dispersive and absorptive dielectric material and compare it with the constant wave case. The group index and the trasmission are investigated for the example of an ensemble of semiconductor quantum dots embedded...

  7. Penetration of slow waves into an overdense plasma

    International Nuclear Information System (INIS)

    Motley, R.W.; Bernabei, S.; Hooke, W.M.; McWilliams, R.; Olson, L.

    1978-06-01

    Probe measurements are reported of the propagation of a 2.45 GHz slow wave launched into a linear, overdense test plasma by a phased double waveguide. We find that waves in the frequency interval omega/sub LH/ < omega < omega/sub pe/ penetrate to the plasma interior only if they satisfy the accessibility criterion

  8. Standing Slow MHD Waves in Radiatively Cooling Coronal Loops ...

    Indian Academy of Sciences (India)

    The standing slow magneto-acoustic oscillations in cooling coronal loops ... turbation and, eventually, reduces the MHD equations to a 1D system modelling ..... where the function Q is expanded in power series with respect to ǫ, i.e.,. Q = Q0 + ...

  9. Schrodinger cat state generation using a slow light

    International Nuclear Information System (INIS)

    Ham, B. S.; Kim, M. S.

    2003-01-01

    We show a practical application of giant Kerr nonlinearity to quantum information processing based on superposition of two distinct macroscopic states- Schrodinger cat state. The giant Kerr nonlinearity can be achieved by using electromagnetically induced transparency, in which light propagation should be slowed down so that a pi-phase shift can be easily obtained owing to increased interaction time.

  10. Formation of Heliospheric Arcs of Slow Solar Wind

    Energy Technology Data Exchange (ETDEWEB)

    Higginson, A. K.; Zurbuchen, T. H. [Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Antiochos, S. K.; DeVore, C. R. [Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Wyper, P. F., E-mail: aleida@umich.edu [Department of Mathematical Sciences, Durham University, Durham DH1 3LE (United Kingdom)

    2017-05-01

    A major challenge in solar and heliospheric physics is understanding the origin and nature of the so-called slow solar wind. The Sun’s atmosphere is divided into magnetically open regions, known as coronal holes, where the plasma streams out freely and fills the solar system, and closed regions, where the plasma is confined to coronal loops. The boundary between these regions extends outward as the heliospheric current sheet (HCS). Measurements of plasma composition strongly imply that much of the slow wind consists of plasma from the closed corona that escapes onto open field lines, presumably by field-line opening or by interchange reconnection. Both of these processes are expected to release closed-field plasma into the solar wind within and immediately adjacent to the HCS. Mysteriously, however, slow wind with closed-field plasma composition is often observed in situ far from the HCS. We use high-resolution, three-dimensional, magnetohydrodynamic simulations to calculate the dynamics of a coronal hole with a geometry that includes a narrow corridor flanked by closed field and is driven by supergranule-like flows at the coronal-hole boundary. These dynamics produce giant arcs of closed-field plasma that originate at the open-closed boundary in the corona, but extend far from the HCS and span tens of degrees in latitude and longitude at Earth. We conclude that such structures can account for the long-puzzling slow-wind observations.

  11. On loneliness and the value of slow reflection

    Directory of Open Access Journals (Sweden)

    Karin van Marle

    2009-09-01

    Full Text Available In this article, the author considers the relationship of law, morality and reconciliation. Intrigued by the political and ethical stances taken by Arendt and McCarthy, the author supports notions of detachment, slowness and social reconciliation concerning contemporary political and ethical questions.

  12. Effects of melatonin implantation during the slow period of cashmere ...

    African Journals Online (AJOL)

    This study was conducted to investigate the effects of melatonin implantation during the slow period of cashmere growth on fibre production in Inner Mongolian cashmere goats. It was found that melatonin implantation had no effect on the growth rate of cashmere, except from February to March when the rate of treated goats ...

  13. Human Growth Hormone (HGH): Does It Slow Aging?

    Science.gov (United States)

    Healthy Lifestyle Healthy aging Human growth hormone is described by some as the key to slowing the aging process. Before you sign up, get the ... slowdown has triggered an interest in using synthetic human growth hormone (HGH) as a way to stave ...

  14. Understanding Bifurcation of Slow Versus Fast Cyber-Attackers

    NARCIS (Netherlands)

    van Wieren, Maarten; Doerr, Christian; Jacobs, Vivian; Pieters, Wolter; Livraga, Giovanni; Torra, Vicenç; Aldini, Alessandro; Martinelli, Fabio; Suri, Neeraj

    2016-01-01

    Anecdotally, the distinction between fast “Smash-and-Grab‿ cyber-attacks on the one hand and slow attacks or “Advanced Persistent Threats‿ on the other hand is well known. In this article, we provide an explanation for this phenomenon as the outcome of an optimization from the perspective of the

  15. Some techniques to improve time structure of slow extracted beam

    International Nuclear Information System (INIS)

    Shoji, Y.; Sato, H.; Toyama, T.; Marutsuka, K.; Sueno, T.; Mikawa, K.; Ninomiya, S.; Yoshii, M.

    1992-01-01

    In order to improve the time structure of slow extracted beam spill for the KEK 12GeV PS, the spill control system has been upgraded by adding feed forward signal to feedback signal. Further, the wake field in the RF cavity has been cancelled by the beam bunch signal to reduce the re-bunch effect during extraction period. (author)

  16. Biochar production from freshwater algae by slow pyrolysis

    Directory of Open Access Journals (Sweden)

    Tanongkiat Kiatsiriroat

    2012-05-01

    Full Text Available A study on the feasibility of biochar production from 3 kinds of freshwateralgae, viz. Spirulina, Spirogyra and Cladophora, was undertaken. Using a slow pyrolysis process in a specially designed reactor, biochar could be generated at 550oC under nitrogen atmosphere. The yields of biochar were between 28-31% of the dry algae.

  17. Generation of slow positron beam and beam bunching

    International Nuclear Information System (INIS)

    Azuma, O.; Satoh, T.; Shitoh, M.; Kaneko, N.; Kawaratani, T.; Hara, O.

    1994-01-01

    Two items are described in this report. One is about the outline of our slow positron beam system, which has been fabricated as a commercial prototype. The other is about the calculation result of positron beam bunching, which will be an additional function to the system. (author)

  18. Slow diuron release formulations based on clay-phosphatidylcholine complexes

    Czech Academy of Sciences Publication Activity Database

    Undabeytia, T.; Recio, E.; Maqueda, C.; Sanchez-Verdejo, T.; Balek, Vladimír

    2012-01-01

    Roč. 55, JAN (2012), s. 53-61 ISSN 0169-1317 R&D Projects: GA MŠk(CZ) LC523 Institutional support: RVO:61388980 Keywords : Diuron * Phosphatidylcholine * Clay mineral * Leaching * Bioactivity * Slow release Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 2.342, year: 2012

  19. Concordance of MRI and EEG Focal Slowing in Nonsyndromic Epilepsy

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2013-04-01

    Full Text Available Investigators at the Kangwon National University, Korea, and The Epilepsy Center, Lurie Children’s Hospital of Chicago, USA studied the correlation and significance of EEG focal slowing and focal MRI abnormalities in 253 children with nonsyndromic epilepsy.

  20. Grating-assisted superresolution of slow waves in Fourier space

    DEFF Research Database (Denmark)

    Thomas, N. Le; Houdré, R.; Frandsen, Lars Hagedorn

    2007-01-01

    with a high numerical aperture Fourier space imaging set-up. A high-resolution spectroscopy of the far-field emission diagram allows us to accurately and efficiently determine the dispersion curve and the group-index dispersion of planar photonic waveguides operating in the slow light regime....

  1. Slow-light enhancement of Beer-Lambert-Bouguer absorption

    OpenAIRE

    Mortensen, Niels Asger; Xiao, Sanshui

    2007-01-01

    We theoretically show how slow light in an optofluidic environment facilitates enhanced light-matter interactions, by orders of magnitude. The proposed concept provides strong opportunities for improving existing miniaturized chemical absorbance cells for Beer-Lambert-Bouguer absorption measurements widely employed in analytical chemistry.

  2. Slow oscillations orchestrating fast oscillations and memory consolidation.

    Science.gov (United States)

    Mölle, Matthias; Born, Jan

    2011-01-01

    Slow-wave sleep (SWS) facilitates the consolidation of hippocampus-dependent declarative memory. Based on the standard two-stage memory model, we propose that memory consolidation during SWS represents a process of system consolidation which is orchestrated by the neocortical memory. The slow oscillations temporally group neuronal activity into up-states of strongly enhanced neuronal activity and down-states of neuronal silence. In a feed-forward efferent action, this grouping is induced not only in the neocortex but also in other structures relevant to consolidation, namely the thalamus generating 10-15Hz spindles, and the hippocampus generating sharp wave-ripples, with the latter well known to accompany a replay of newly encoded memories taking place in hippocampal circuitries. The feed-forward synchronizing effect of the slow oscillation enables the formation of spindle-ripple events where ripples and accompanying reactivated hippocampal memory information become nested into the single troughs of spindles. Spindle-ripple events thus enable reactivated memory-related hippocampal information to be fed back to neocortical networks in the excitable slow oscillation up-state where they can induce enduring plastic synaptic changes underlying the effective formation of long-term memories. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Chondrogenic differentiation of ATDC5-cells under the influence of Mg and Mg alloy degradation.

    Science.gov (United States)

    Martinez Sanchez, Adela H; Feyerabend, Frank; Laipple, Daniel; Willumeit-Römer, Regine; Weinberg, Annelie; Luthringer, Bérengère J C

    2017-03-01

    Biodegradable magnesium (Mg)-based materials are a potential alternative to permanent implants for application in children. Nevertheless effects of those materials on growth plate cartilage and chondrogenesis have not been previously evaluated. In vitro differentiation of ATDC5 cells was evaluated under the influence of pure Mg (PMg), Mg with 10wt% of gadolinium (Mg-10Gd) and Mg with 2wt% of silver (Mg-2Ag) degradation products (extracts) and direct cell culture on the materials. Gene expression showed an inhibitory effect on ATDC5 mineralization with the three extracts and a chondrogenic potential of Mg-10Gd. Cells cultured in Mg-10Gd and Mg-2Ag extracts showed the same proliferation and morphology than cells cultured in growth conditions. Mg-10Gd induced an increase in production of ECM and a bigger cell size, similar to the effects found with differentiation conditions. An increased metabolic activity was observed in cells cultured under the influence of Mg-10Gd extracts, indicated by an acidic pH during most of the culture period. After 7days of culture on the materials, ATDC5 growth, distribution and ECM synthesis were higher on Mg-10Gd samples, followed by Mg-2Ag and PMg, which was influenced by the homogeneity and composition of the degradation layer. This study confirmed the tolerance of ATDC5 cells to Mg-based materials and a chondrogenic effect of Mg-10Gd. Further studies in vitro and in vivo are necessary to evaluate cell reactions to those materials, as well as the effects on bone growth and the biocompatibility of the alloying system in the body. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Crystal plastic earthquakes in dolostones: from slow to fast ruptures.

    Science.gov (United States)

    Passelegue, F. X.; Aubry, J.; Nicolas, A.; Fondriest, M.; Schubnel, A.; Di Toro, G.

    2017-12-01

    Dolostone is the most dominant lithology of the seismogenic upper crust around the Mediterranean Sea. Understanding the internal mechanisms controlling fault friction is crucial for understanding seismicity along active faults. Displacement in such fault zones is frequently highlighted by highly reflective (mirror-like) slip surfaces, created by thin films of nanogranular fault rock. Using saw-cut dolostone samples coming from natural fault zones, we conducted stick-slip experiments under triaxial loading conditions at 30, 60 and 90 MPa confining pressure and temperature ranging from 30 to 100 degrees C. At 30 and 65 degrees C, only slow rupture was observed and the experimental fault exhibits frictional behaviour, i.e. a dependence of normal stress on peak shear stress. At 65 degrees C, a strengthening behaviour is observed after the main rupture, leading to a succession of slow rupture. At 100 degrees C, the macroscopic behaviour of the fault becomes ductile, and no dependence of pressure on the peak shear stress is observed. In addition, the increase of the confining pressure up to 60 and 90 MPa allow the transition from slow to fast rupture, highlighted by the records of acoustic activity and by dynamic stress drop occurring in a few tens of microseconds. Using strain gages located along the fault surface and acoustic transducers, we were able to measure the rupture velocities during slow and fast rupture. Slow ruptures propagated around 0.1 m/s, in agreement with natural observations. Fast ruptures propagated up to supershear velocities, i.e. faster than the shear wave speed (>3500 m/s). A complete study of the microstructures was realized before and after ruptures. Slow ruptures lead to the production of mirror-like surface driven by the production of nanograins due to dislocation processes. Fast ruptures induce the production of amorphous material along the fault surface, which may come from decarbonation and melting processes. We demonstrate that the

  5. Characteristics of broadband slow earthquakes explained by a Brownian model

    Science.gov (United States)

    Ide, S.; Takeo, A.

    2017-12-01

    Brownian slow earthquake (BSE) model (Ide, 2008; 2010) is a stochastic model for the temporal change of seismic moment release by slow earthquakes, which can be considered as a broadband phenomena including tectonic tremors, low frequency earthquakes, and very low frequency (VLF) earthquakes in the seismological frequency range, and slow slip events in geodetic range. Although the concept of broadband slow earthquake may not have been widely accepted, most of recent observations are consistent with this concept. Then, we review the characteristics of slow earthquakes and how they are explained by BSE model. In BSE model, the characteristic size of slow earthquake source is represented by a random variable, changed by a Gaussian fluctuation added at every time step. The model also includes a time constant, which divides the model behavior into short- and long-time regimes. In nature, the time constant corresponds to the spatial limit of tremor/SSE zone. In the long-time regime, the seismic moment rate is constant, which explains the moment-duration scaling law (Ide et al., 2007). For a shorter duration, the moment rate increases with size, as often observed for VLF earthquakes (Ide et al., 2008). The ratio between seismic energy and seismic moment is constant, as shown in Japan, Cascadia, and Mexico (Maury et al., 2017). The moment rate spectrum has a section of -1 slope, limited by two frequencies corresponding to the above time constant and the time increment of the stochastic process. Such broadband spectra have been observed for slow earthquakes near the trench axis (Kaneko et al., 2017). This spectrum also explains why we can obtain VLF signals by stacking broadband seismograms relative to tremor occurrence (e.g., Takeo et al., 2010; Ide and Yabe, 2014). The fluctuation in BSE model can be non-Gaussian, as far as the variance is finite, as supported by the central limit theorem. Recent observations suggest that tremors and LFEs are spatially characteristic

  6. Mg/Ca of Continental Ostracode Shells

    Science.gov (United States)

    Ito, E.; Forester, R. M.; Marco-Barba, J.; Mezquita, F.

    2007-12-01

    Marine ionic chemistry is thought to remain constant. This, together with the belief that marine calcifiers partition Mg/Ca in a systematic manner as functions of temperature (and Mg/Ca) of water forms the basis of the Mg/Ca thermometer. In continental settings both of these assumptions are usually not true. Continental waters contain a wide variety of solutes in absolute and relative ion concentrations. Hence, waters with identical Mg/Ca may have very different concentrations of Mg and Ca and very different anions. Here we use two examples to focus on the effects of ion chemistry on Mg/Ca partitioning in continental ostracode shells and we ignore the complexities of solute evolution, which can change Mg/Ca over timescales of minutes to millennia. Palacios-Fest and Dettman (2001) conducted a monthly study of ,Cypridopsis vidua at El Yeso Lake in Sonora, Mexico. They established a relation between temperature and average shell Mg/Ca using regression analyses on averaged data. When their Mg/Ca-temperature relation is applied to monthly ,C. vidua data from Page Pond near Cleveland, Ohio, water temperatures of -8 to -1°C are obtained. The observed Mg/Ca ranges for El Yeso Lake (0.31 to 0.46) and Page Pond (0.33 to 0.46) are similar, as are their specific conductivities (700 to 850μS for El Yeso Lake; 400 to 600μS for Page Pond). However, [Ca] is 140-260 mg/L for El Yeso, but only 70-90 mg/L for Page Pond. Page Pond data, in fact, shows a good temperature shell Mg/Ca relation for .C. vidua, but the relation is different from that at El Yeso. Hence, shell Mg/Ca is a multi-valued, family of curves function of temperature and Mg/Ca of water that depends on the [Mg] and [Ca] values in water and perhaps other factors. Our second example comes from sites near Valencia, Spain and involves shell data for ,Cyprideis torosa, an estuarine ostracode that is tolerant of a wide range of salinity and can live in continental waters as long as the carbonate alkalinity to Ca ratio is

  7. Prussian Blue Mg-Li Hybrid Batteries.

    Science.gov (United States)

    Sun, Xiaoqi; Duffort, Victor; Nazar, Linda F

    2016-08-01

    The major advantage of Mg batteries relies on their promise of employing an Mg metal negative electrode, which offers much higher energy density compared to graphitic carbon. However, the strong coulombic interaction of Mg 2+ ions with anions leads to their sluggish diffusion in the solid state, which along with a high desolvation energy, hinders the development of positive electrode materials. To circumvent this limitation, Mg metal negative electrodes can be used in hybrid systems by coupling an Li + insertion cathode through a dual salt electrolyte. Two "high voltage" Prussian blue analogues (average 2.3 V vs Mg/Mg 2+ ; 3.0 V vs Li/Li + ) are investigated as cathode materials and the influence of structural water is shown. Their electrochemical profiles, presenting two voltage plateaus, are explained based on the two unique Fe bonding environments. Structural water has a beneficial impact on the cell voltage. Capacities of 125 mAh g -1 are obtained at a current density of 10 mA g -1 (≈C/10), while stable performance up to 300 cycles is demonstrated at 200 mA g -1 (≈2C). The hybrid cell design is a step toward building a safe and high density energy storage system.

  8. Continuous neutron slowing down theory applied to resonances

    International Nuclear Information System (INIS)

    Segev, M.

    1977-01-01

    Neutronic formalisms that discretize the neutron slowing down equations in large numerical intervals currently account for the bulk effect of resonances in a given interval by the narrow resonance approximation (NRA). The NRA reduces the original problem to an efficient numerical formalism through two assumptions: resonance narrowness with respect to the scattering bands in the slowing down equations and resonance narrowness with respect to the numerical intervals. Resonances at low energies are narrow neither with respect to the slowing down ranges nor with respect to the numerical intervals, which are usually of a fixed lethargy width. Thus, there are resonances to which the NRA is not applicable. To stay away from the NRA, the continuous slowing down (CSD) theory of Stacey was invoked. The theory is based on a linear expansion in lethargy of the collision density in integrals of the slowing down equations and had notable success in various problems. Applying CSD theory to the assessment of bulk resonance effects raises the problem of obtaining efficient quadratures for integrals involved in the definition of the so-called ''moderating parameter.'' The problem was solved by two approximations: (a) the integrals were simplified through a rationale, such that the correct integrals were reproduced for very narrow or very wide resonances, and (b) the temperature-broadened resonant line shapes were replaced by nonbroadened line shapes to enable analytical integration. The replacement was made in such a way that the integrated capture and scattering probabilities in each resonance were preserved. The resulting formalism is more accurate than the narrow-resonance formalisms and is equally as efficient

  9. The slow cell death response when screening chemotherapeutic agents.

    Science.gov (United States)

    Blois, Joseph; Smith, Adam; Josephson, Lee

    2011-09-01

    To examine the correlation between cell death and a common surrogate of death used in screening assays, we compared cell death responses to those obtained with the sulforhodamine B (SRB) cell protein-based "cytotoxicity" assay. With the SRB assay, the Hill equation was used to obtain an IC50 and final cell mass, or cell mass present at infinite agent concentrations, with eight adherent cell lines and four agents (32 agent/cell combinations). Cells were treated with high agent concentrations (well above the SRB IC50) and the death response determined as the time-dependent decrease in cells failing to bind both annexin V and vital fluorochromes by flow cytometry. Death kinetics were categorized as fast (5/32) (similar to the reference nonadherent Jurkat line), slow (17/32), or none (10/32), despite positive responses in the SRB assay in all cases. With slow cell death, a single exposure to a chemotherapeutic agent caused a slow, progressive increase in dead (necrotic) and dying (apoptotic) cells for at least 72 h. Cell death (defined by annexin and/or fluorochrome binding) did not correlate with the standard SRB "cytotoxicity" assay. With the slow cell death response, a single exposure to an agent caused a slow conversion from vital to apoptotic and necrotic cells over at least 72 h (the longest time point examined). Here, increasing the time of exposure to agent concentrations modestly above the SRB IC50 provides a method of maximizing cell kill. If tumors respond similarly, sustained low doses of chemotherapeutic agents, rather than a log-kill, maximum tolerated dose strategy may be an optimal strategy of maximizing tumor cell death.

  10. A Model fot the Sources of the Slow Solar Wind

    Science.gov (United States)

    Antiochos, S. K.; Mikic, Z.; Titov, V. S.; Lionello, R.; Linker, J. A.

    2011-01-01

    Models for the origin of the slow solar wind must account for two seemingly contradictory observations: the slow wind has the composition of the closed-field corona, implying that it originates from the continuous opening and closing of flux at the boundary between open and closed field. On the other hand, the slow wind also has large angular width, up to approx.60deg, suggesting that its source extends far from the open-closed boundary. We propose a model that can explain both observations. The key idea is that the source of the slow wind at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices and quasi-separatrix layers in the heliosphere. We compute analytically the topology of an open-field corridor and show that it produces a quasi-separatrix layer in the heliosphere that extends to angles far from the heliospheric current sheet. We then use an MHD code and MDI/SOHO observations of the photospheric magnetic field to calculate numerically, with high spatial resolution, the quasi-steady solar wind, and magnetic field for a time period preceding the 2008 August 1 total solar eclipse. Our numerical results imply that, at least for this time period, a web of separatrices (which we term an S-web) forms with sufficient density and extent in the heliosphere to account for the observed properties of the slow wind. We discuss the implications of our S-web model for the structure and dynamics of the corona and heliosphere and propose further tests of the model. Key words: solar wind - Sun: corona - Sun: magnetic topology

  11. A Model for the Sources of the Slow Solar Wind

    Science.gov (United States)

    Antiochos, S. K.; Mikić, Z.; Titov, V. S.; Lionello, R.; Linker, J. A.

    2011-04-01

    Models for the origin of the slow solar wind must account for two seemingly contradictory observations: the slow wind has the composition of the closed-field corona, implying that it originates from the continuous opening and closing of flux at the boundary between open and closed field. On the other hand, the slow wind also has large angular width, up to ~60°, suggesting that its source extends far from the open-closed boundary. We propose a model that can explain both observations. The key idea is that the source of the slow wind at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices and quasi-separatrix layers in the heliosphere. We compute analytically the topology of an open-field corridor and show that it produces a quasi-separatrix layer in the heliosphere that extends to angles far from the heliospheric current sheet. We then use an MHD code and MDI/SOHO observations of the photospheric magnetic field to calculate numerically, with high spatial resolution, the quasi-steady solar wind, and magnetic field for a time period preceding the 2008 August 1 total solar eclipse. Our numerical results imply that, at least for this time period, a web of separatrices (which we term an S-web) forms with sufficient density and extent in the heliosphere to account for the observed properties of the slow wind. We discuss the implications of our S-web model for the structure and dynamics of the corona and heliosphere and propose further tests of the model.

  12. Formation and Corrosion Resistance of Mg-Al Hydrotalcite Film on Mg-Gd-Zn Alloy

    Science.gov (United States)

    Ba, Z. X.; Dong, Q. S.; Kong, S. X.; Zhang, X. B.; Xue, Y. J.; Chen, Y. J.

    2017-06-01

    An environment-friendly technique for depositing a Mg-Al hydrotalcite (HT) (Mg6Al2(OH)16-CO3ṡ4H2O) conversion film was developed to protect the Mg-Gd-Zn alloy from corrosion. The morphology and chemical compositions of the film were analyzed by scanning electronic microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy (RS), respectively. The electrochemical test and hydrogen evolution test were employed to evaluate the biocorrosion behavior of Mg-Gd-Zn alloy coated with the Mg-Al HT film in the simulated body fluid (SBF). It was found that the formation of Mg-Al HT film was a transition from amorphous precursor to a crystalline HT structure. The HT film can effectively improve the corrosion resistance of magnesium alloy. It indicates that the process provides a promising approach to modify Mg-Gd-Zn alloy.

  13. Microstructural evolution in Mg-rich Mg-Zn-Y alloys

    International Nuclear Information System (INIS)

    Biswas, T.; Ranganathan, S.; Nair, S.; Bajargan, G.

    2005-01-01

    Mg-rich Mg-Zn-Y alloys with nominal compositions Mg 97 Zn 1 Y 2 , Mg 97 Zn 2 Y 1 , Mg 92 Zn 6.5 Y 1.5 and Mg 97-x Zn 1 Y 2 Zr x have been chosen for the present study. These alloys are prepared by using sand casting mold. The sand cast alloys are remelted and subjected to copper mold casting and melt spinning techniques. The effect of cooling rate on microstructures was studied. It is observed that the size of the precipitates decreases with an increase of cooling rate. The formation of nano precipitates results in higher strength of the alloy as compared to the conventional alloys. The microstructures of melt spun ribbons are compared with RS/PM (rapidly solidified power metallurgy) Mg 97 Zn 1 Y 2 alloy, obtained from a different source. (author)

  14. Melting relations in the MgO-MgSiO3 system up to 70 GPa

    Science.gov (United States)

    Ohnishi, Satoka; Kuwayama, Yasuhiro; Inoue, Toru

    2017-06-01

    Melting experiments in a binary system MgO-MgSiO3 were performed up to 70 GPa using a CO2 laser heated diamond anvil cell. The quenched samples were polished and analyzed by a dualbeam focused ion beam (FIB) and a field emission scanning electron microscope (FE-SEM), respectively. The liquidus phase and the eutectic composition were determined on the basis of textual and chemical analyses of sample cross sections. Our experimental results show that the eutectic composition is the Si/Mg molar ratio of 0.76 at 35 GPa and it decreases with increasing pressure. Above 45 GPa, it becomes relatively constant at about 0.64-0.65 Si/Mg molar ratio. Using our experimental data collected at a wide pressure range up to 70 GPa together with previous experimental data, we have constructed a thermodynamic model of the eutectic composition of the MgO-MgSiO3 system. The eutectic composition extrapolated to the pressure and temperature conditions at the base of the mantle is about 0.64 Si/Mg molar ratio. The modeled eutectic composition is quite consistent with a previous prediction from ab initio calculations (de Koker et al. in Earth Planet Sci Lett 361:58-63, 2013), suggesting that the simple assumption of a non-ideal regular solution model can well describe the melting relation of the MgO-MgSiO3 system at high pressure. Our results show that the liquidus phase changes from MgO-periclase to MgSiO3-bridgmanite at 35 GPa for the simplified pyrolite composition ( 0.7 Si/Mg molar ratio), while MgSiO3-bridgmanite is the liquidus phase at the entire lower mantle conditions for the chondritic composition ( 0.84 Si/Mg molar ratio).

  15. Chondrogenic differentiation of ATDC5-cells under the influence of Mg and Mg alloy degradation

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Sanchez, Adela H., E-mail: adela.martinez@hzg.de [Helmholtz-Zentrum Geesthacht, Institute of Material Research, Department for Structural Research on Macromolecules, Geesthacht (Germany); Feyerabend, Frank; Laipple, Daniel; Willumeit-Römer, Regine [Helmholtz-Zentrum Geesthacht, Institute of Material Research, Department for Structural Research on Macromolecules, Geesthacht (Germany); Weinberg, Annelie [Department of Orthopedics and Orthopedic Surgery, Medical University of Graz (Austria); Luthringer, Bérengère J.C. [Helmholtz-Zentrum Geesthacht, Institute of Material Research, Department for Structural Research on Macromolecules, Geesthacht (Germany)

    2017-03-01

    Biodegradable magnesium (Mg)-based materials are a potential alternative to permanent implants for application in children. Nevertheless effects of those materials on growth plate cartilage and chondrogenesis have not been previously evaluated. In vitro differentiation of ATDC5 cells was evaluated under the influence of pure Mg (PMg), Mg with 10 wt% of gadolinium (Mg-10Gd) and Mg with 2 wt% of silver (Mg-2Ag) degradation products (extracts) and direct cell culture on the materials. Gene expression showed an inhibitory effect on ATDC5 mineralization with the three extracts and a chondrogenic potential of Mg-10Gd. Cells cultured in Mg-10Gd and Mg-2Ag extracts showed the same proliferation and morphology than cells cultured in growth conditions. Mg-10Gd induced an increase in production of ECM and a bigger cell size, similar to the effects found with differentiation conditions. An increased metabolic activity was observed in cells cultured under the influence of Mg-10Gd extracts, indicated by an acidic pH during most of the culture period. After 7 days of culture on the materials, ATDC5 growth, distribution and ECM synthesis were higher on Mg-10Gd samples, followed by Mg-2Ag and PMg, which was influenced by the homogeneity and composition of the degradation layer. This study confirmed the tolerance of ATDC5 cells to Mg-based materials and a chondrogenic effect of Mg-10Gd. Further studies in vitro and in vivo are necessary to evaluate cell reactions to those materials, as well as the effects on bone growth and the biocompatibility of the alloying system in the body. - Highlights: • Degradation of PMg, and Mg-2Ag do not influence ATDC5 cells growth and chondrogenic redifferentiation. • Mg-10Gd enhances fast chondrogenic redifferentiation and expression of hyperthrophic markers on ATDC5 cells. • Further evaluation of the effects of PMg, Mg-10Gd and Mg-2Ag in vivo are necessary to confirm its potential for application in growing bones.

  16. Chondrogenic differentiation of ATDC5-cells under the influence of Mg and Mg alloy degradation

    International Nuclear Information System (INIS)

    Martinez Sanchez, Adela H.; Feyerabend, Frank; Laipple, Daniel; Willumeit-Römer, Regine; Weinberg, Annelie; Luthringer, Bérengère J.C.

    2017-01-01

    Biodegradable magnesium (Mg)-based materials are a potential alternative to permanent implants for application in children. Nevertheless effects of those materials on growth plate cartilage and chondrogenesis have not been previously evaluated. In vitro differentiation of ATDC5 cells was evaluated under the influence of pure Mg (PMg), Mg with 10 wt% of gadolinium (Mg-10Gd) and Mg with 2 wt% of silver (Mg-2Ag) degradation products (extracts) and direct cell culture on the materials. Gene expression showed an inhibitory effect on ATDC5 mineralization with the three extracts and a chondrogenic potential of Mg-10Gd. Cells cultured in Mg-10Gd and Mg-2Ag extracts showed the same proliferation and morphology than cells cultured in growth conditions. Mg-10Gd induced an increase in production of ECM and a bigger cell size, similar to the effects found with differentiation conditions. An increased metabolic activity was observed in cells cultured under the influence of Mg-10Gd extracts, indicated by an acidic pH during most of the culture period. After 7 days of culture on the materials, ATDC5 growth, distribution and ECM synthesis were higher on Mg-10Gd samples, followed by Mg-2Ag and PMg, which was influenced by the homogeneity and composition of the degradation layer. This study confirmed the tolerance of ATDC5 cells to Mg-based materials and a chondrogenic effect of Mg-10Gd. Further studies in vitro and in vivo are necessary to evaluate cell reactions to those materials, as well as the effects on bone growth and the biocompatibility of the alloying system in the body. - Highlights: • Degradation of PMg, and Mg-2Ag do not influence ATDC5 cells growth and chondrogenic redifferentiation. • Mg-10Gd enhances fast chondrogenic redifferentiation and expression of hyperthrophic markers on ATDC5 cells. • Further evaluation of the effects of PMg, Mg-10Gd and Mg-2Ag in vivo are necessary to confirm its potential for application in growing bones.

  17. Slow wave activity and slow oscillations in sleepwalkers and controls: effects of 38 h of sleep deprivation.

    Science.gov (United States)

    Perrault, Rosemarie; Carrier, Julie; Desautels, Alex; Montplaisir, Jacques; Zadra, Antonio

    2013-08-01

    Sleepwalkers have been shown to have an unusually high number of arousals from slow wave sleep and lower slow wave activity (SWA) power during the night than controls. Because sleep deprivation increases the frequency of slow wave sleep (SWS) arousals in sleepwalkers, it may also affect the expression of the homeostatic process to a greater extent than shown previously. We thus investigated SWA power as well as slow wave oscillation (SWO) density in 10 sleepwalkers and nine controls at baseline and following 38 h of sleep deprivation. There was a significant increase in SWA during participants' recovery sleep, especially during their second non-rapid eye movement (NREM) period. SWO density was similarly increased during recovery sleep's first two NREM periods. A fronto-central gradient in SWA and SWO was also present on both nights. However, no group differences were noted on any of the 2 nights on SWA or SWO. This unexpected result may be related to the heterogeneity of sleepwalkers as a population, as well as our small sample size. SWA pressure after extended sleep deprivation may also result in a ceiling effect in both sleepwalkers and controls. © 2013 European Sleep Research Society.

  18. Children with Dyslexia Are Slow Writers Because They Pause More Often and Not Because They Are Slow at Handwriting Execution

    Science.gov (United States)

    Sumner, Emma; Connelly, Vincent; Barnett, Anna L.

    2013-01-01

    It is commonly assumed that children with dyslexia are slower at handwriting than other children. However, evidence of slow handwriting in children with dyslexia is very mixed. Thirty-one children with dyslexia, aged 9 years, were compared to both age-matched children and younger spelling-ability matched children. Participants completed an…

  19. Stochastic dynamic modeling of regular and slow earthquakes

    Science.gov (United States)

    Aso, N.; Ando, R.; Ide, S.

    2017-12-01

    Both regular and slow earthquakes are slip phenomena on plate boundaries and are simulated by a (quasi-)dynamic modeling [Liu and Rice, 2005]. In these numerical simulations, spatial heterogeneity is usually considered not only for explaining real physical properties but also for evaluating the stability of the calculations or the sensitivity of the results on the condition. However, even though we discretize the model space with small grids, heterogeneity at smaller scales than the grid size is not considered in the models with deterministic governing equations. To evaluate the effect of heterogeneity at the smaller scales we need to consider stochastic interactions between slip and stress in a dynamic modeling. Tidal stress is known to trigger or affect both regular and slow earthquakes [Yabe et al., 2015; Ide et al., 2016], and such an external force with fluctuation can also be considered as a stochastic external force. A healing process of faults may also be stochastic, so we introduce stochastic friction law. In the present study, we propose a stochastic dynamic model to explain both regular and slow earthquakes. We solve mode III problem, which corresponds to the rupture propagation along the strike direction. We use BIEM (boundary integral equation method) scheme to simulate slip evolution, but we add stochastic perturbations in the governing equations, which is usually written in a deterministic manner. As the simplest type of perturbations, we adopt Gaussian deviations in the formulation of the slip-stress kernel, external force, and friction. By increasing the amplitude of perturbations of the slip-stress kernel, we reproduce complicated rupture process of regular earthquakes including unilateral and bilateral ruptures. By perturbing external force, we reproduce slow rupture propagation at a scale of km/day. The slow propagation generated by a combination of fast interaction at S-wave velocity is analogous to the kinetic theory of gasses: thermal

  20. Effects of limestone, N, K and Mg fertilizers on Mg absorption by oats and barley

    Energy Technology Data Exchange (ETDEWEB)

    Alston, A M

    1966-01-01

    Oats grown in a pot experiment on two sandy loams were sampled at four stages of growth. Neither KCl nor MgSO/sub 4/. 7H/sub 2/O had any effect on yield but % Mg and total Mg uptake were consistently decreased by applying K and increased by applying Mg. Ca(NO/sub 3/)/sub 2/ increased % Mg more than did (NH/sub 4/)/sub 2/SO/sub 4/, but yield and total Mg uptake were higher where (NH/sub 4/)/sub 2/SO/sub 4/ was applied. The effects of fertilizers were similar on both soils. The effects of applying (NH/sub 4/)/sub 2/SO/sub 4/ and NaNO/sub 2/ to the soil on % Mg in barley were compared in a field experiment on an acid loam to which several rates of limestone had been applied. Treatments had no effect on the % Mg in grain or straw at maturity. At four earlier stages of growth (NH/sub 4/)/sub 2/SO)/sub 4/ increased % Mg in the plants more than did NaNO/sub 2/. Limestone slightly increased % Mg. Nitrification of NH/sub 4/ in the soil was rapid.

  1. Mg Incorporation Efficiency in Pulsed MOCVD of N-Polar GaN:Mg

    Science.gov (United States)

    Marini, Jonathan; Mahaboob, Isra; Hogan, Kasey; Novak, Steve; Bell, L. D.; Shahedipour-Sandvik, F.

    2017-10-01

    We report on the effect of growth polarity and pulsed or δ -doped growth mode on impurity incorporation in metalorganic chemical vapor deposition-grown GaN. In Ga-polar orientation, up to 12× enhancement in Mg concentration for given Mg flow rate is observed, resulting in enhanced p-type conductivity for these samples. In contrast, this enhancement effect is greatly diminished for N-polar samples, falling off with increasing Mg flow and showing maximum enhancement of 2.7× at 30 nmol/min Mg flow. At higher Mg flow rates, Mg incorporation at normal levels did not correspond to p-type conductivity, which may be due to Mg incorporation at nonacceptor sites. Concentrations of C, O, and Si were also investigated, revealing dependence on Mg flow in N-polar pulsed samples. Carbon incorporation was found to decrease with increasing Mg flow, and oxygen incorporation was found to remain high across varied Mg flow. These effects combine to result in N-polar samples that are not p-type when using the pulsed growth mode.

  2. Structural characteristics and corrosion behavior of biodegradable Mg-Zn, Mg-Zn-Gd alloys.

    Science.gov (United States)

    Kubásek, J; Vojtěch, D

    2013-07-01

    In this research, binary Mg-Zn (up to 3 wt% Zn) and ternary Mg-Zn-Gd (up to 3 wt% Gd, 3 wt% Zn) alloys were prepared by induction melting in an argon atmosphere. The structures of these alloys were characterized using light and scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction and X-ray fluorescence. In addition, Brinell hardness measurements were taken to supplement these studies. Corrosion behavior was evaluated by immersion tests and potentiodynamic measurements in a physiological solution (9 g/l NaCl). Depending on the composition, structures of the as-cast alloys contained α-Mg dendrites, MgZn, Mg5Gd and Mg3Gd2Zn3 phases. Compared to pure Mg, zinc improved the corrosion resistance of binary Mg-Zn. Gadolinium also improved the corrosion resistance in the case of Mg-1Zn-3Gd alloy. The highest corrosion rate was observed for Mg-3Zn-3Gd alloy. Our results improve the understanding of the relationships between the structure and corrosion behavior of our studied alloy systems.

  3. High-Strength Low-Alloy (HSLA) Mg-Zn-Ca Alloys with Excellent Biodegradation Performance

    Science.gov (United States)

    Hofstetter, J.; Becker, M.; Martinelli, E.; Weinberg, A. M.; Mingler, B.; Kilian, H.; Pogatscher, S.; Uggowitzer, P. J.; Löffler, J. F.

    2014-04-01

    This article deals with the development of fine-grained high-strength low-alloy (HSLA) magnesium alloys intended for use as biodegradable implant material. The alloys contain solely low amounts of Zn and Ca as alloying elements. We illustrate the development path starting from the high-Zn-containing ZX50 (MgZn5Ca0.25) alloy with conventional purity, to an ultrahigh-purity ZX50 modification, and further to the ultrahigh-purity Zn-lean alloy ZX10 (MgZn1Ca0.3). It is shown that alloys with high Zn-content are prone to biocorrosion in various environments, most probably because of the presence of the intermetallic phase Mg6Zn3Ca2. A reduction of the Zn content results in (Mg,Zn)2Ca phase formation. This phase is less noble than the Mg-matrix and therefore, in contrast to Mg6Zn3Ca2, does not act as cathodic site. A fine-grained microstructure is achieved by the controlled formation of fine and homogeneously distributed (Mg,Zn)2Ca precipitates, which influence dynamic recrystallization and grain growth during hot forming. Such design scheme is comparable to that of HSLA steels, where low amounts of alloying elements are intended to produce a very fine dispersion of particles to increase the material's strength by refining the grain size. Consequently our new, ultrapure ZX10 alloy exhibits high strength (yield strength R p = 240 MPa, ultimate tensile strength R m = 255 MPa) and simultaneously high ductility (elongation to fracture A = 27%), as well as low mechanical anisotropy. Because of the anodic nature of the (Mg,Zn)2Ca particles used in the HSLA concept, the in vivo degradation in a rat femur implantation study is very slow and homogeneous without clinically observable hydrogen evolution, making the ZX10 alloy a promising material for biodegradable implants.

  4. Nifedipine for angina and acute myocardial ischemia

    NARCIS (Netherlands)

    P.G. Hugenholtz (Paul); J.W. de Jong (Jan Willem); P.D. Verdouw (Pieter); P.W.J.C. Serruys (Patrick)

    1983-01-01

    textabstractThis paper reviews the mechanisms believed to be responsible for myocardial ischaemia and the mode of action of calcium antagonist drugs. The clinical management of patients with myocardial ischaemia is discussed in the context of current knowledge about patho-physiology and drug action.

  5. Thermoelectric power of PrMg3

    Science.gov (United States)

    Isikawa, Yosikazu; Somiya, Kazuya; Koyanagi, Huruto; Mizushima, Toshio; Kuwai, Tomohiko; Tayama, Takashi

    2010-01-01

    PrMg3 is supposed to be one of the strongly correlated electron systems originated from the hybridization between the Pr 4f and conduction electrons, because the gigantic electronic specific heat coefficient C/T was observed at low temperatures. However, a typical behaviour of - ln T dependence was not observed in the temperature dependence of the electrical resistivity. The thermoelectric power S is a powerful tool to investigate the density of states at the Fermi energy. We measured carefully the thermoelectric power of PrMg3 in the temperature range between 2 and 300 K. S is extremely small, ranged within ±1 μV/K over the whole temperature. The value of S/T at low temperature limit was also significantly smaller than expected from the specific heat results. We therefore conclude that the density of state at the Fermi level is not enhanced in PrMg3.

  6. Thermoelectric power of PrMg3

    International Nuclear Information System (INIS)

    Isikawa, Yosikazu; Somiya, Kazuya; Koyanagi, Huruto; Mizushima, Toshio; Kuwai, Tomohiko; Tayama, Takashi

    2010-01-01

    PrMg 3 is supposed to be one of the strongly correlated electron systems originated from the hybridization between the Pr 4f and conduction electrons, because the gigantic electronic specific heat coefficient C/T was observed at low temperatures. However, a typical behaviour of - ln T dependence was not observed in the temperature dependence of the electrical resistivity. The thermoelectric power S is a powerful tool to investigate the density of states at the Fermi energy. We measured carefully the thermoelectric power of PrMg 3 in the temperature range between 2 and 300 K. S is extremely small, ranged within ±1 μV/K over the whole temperature. The value of S/T at low temperature limit was also significantly smaller than expected from the specific heat results. We therefore conclude that the density of state at the Fermi level is not enhanced in PrMg 3 .

  7. Elements of slow-neutron scattering basics, techniques, and applications

    CERN Document Server

    Carpenter, J M

    2015-01-01

    Providing a comprehensive and up-to-date introduction to the theory and applications of slow-neutron scattering, this detailed book equips readers with the fundamental principles of neutron studies, including the background and evolving development of neutron sources, facility design, neutron scattering instrumentation and techniques, and applications in materials phenomena. Drawing on the authors' extensive experience in this field, this text explores the implications of slow-neutron research in greater depth and breadth than ever before in an accessible yet rigorous manner suitable for both students and researchers in the fields of physics, biology, and materials engineering. Through pedagogical examples and in-depth discussion, readers will be able to grasp the full scope of the field of neutron scattering, from theoretical background through to practical, scientific applications.

  8. Identifying Slow Molecular Motions in Complex Chemical Reactions.

    Science.gov (United States)

    Piccini, GiovanniMaria; Polino, Daniela; Parrinello, Michele

    2017-09-07

    We have studied the cyclization reaction of deprotonated 4-chloro-1-butanethiol to tetrahydrothiophene by means of well-tempered metadynamics. To properly select the collective variables, we used the recently proposed variational approach to conformational dynamics within the framework of metadyanmics. This allowed us to select the appropriate linear combinations from a set of collective variables representing the slow degrees of freedom that best describe the slow modes of the reaction. We performed our calculations at three different temperatures, namely, 300, 350, and 400 K. We show that the choice of such collective variables allows one to easily interpret the complex free-energy surface of such a reaction by univocal identification of the conformers belonging to reactants and product states playing a fundamental role in the reaction mechanism.

  9. An ultra-fine group slowing down benchmark

    International Nuclear Information System (INIS)

    Ganapol, B. D.; Maldonado, G. I.; Williams, M. L.

    2009-01-01

    We suggest a new solution to the neutron slowing down equation in terms of multi-energy panels. Our motivation is to establish a computational benchmark featuring an ultra-fine group calculation, where the number of groups could be on the order of 100,000. While the CENTRM code of the SCALE code package has been shown to adequately treat this many groups, there is always a need for additional verification. The multi panel solution principle is simply to consider the slowing down region as sub regions of panels, with each panel a manageable number of groups, say 100. In this way, we reduce the enormity of dealing with the entire spectrum all at once by considering many smaller problems. We demonstrate the solution in the unresolved U3o8 resonance region. (authors)

  10. Slow light and pulse propagation in semiconductor waveguides

    DEFF Research Database (Denmark)

    Hansen, Per Lunnemann

    This thesis concerns the propagation of optical pulses in semiconductor waveguide structures with particular focus on methods for achieving slow light or signal delays. Experimental pulse propagation measurements of pulses with a duration of 180 fs, transmitted through quantum well based waveguide...... structures, are presented. Simultaneous measurements of the pulse transmission and delay are measured as a function of input pulse energy for various applied electrical potentials. Electrically controlled pulse delay and advancement are demonstrated and compared with a theoretical model. The limits...... of the model as well as the underlying physical mechanisms are analysed and discussed. A method to achieve slow light by electromagnetically induced transparency (EIT) in an inhomogeneously broadened quantum dot medium is proposed. The basic principles of EIT are assessed and the main dissimilarities between...

  11. Can power spectrum observations rule out slow-roll inflation?

    Science.gov (United States)

    Vieira, J. P. P.; Byrnes, Christian T.; Lewis, Antony

    2018-01-01

    The spectral index of scalar perturbations is an important observable that allows us to learn about inflationary physics. In particular, a detection of a significant deviation from a constant spectral index could enable us to rule out the simplest class of inflation models. We investigate whether future observations could rule out canonical single-field slow-roll inflation given the parameters allowed by current observational constraints. We find that future measurements of a constant running (or running of the running) of the spectral index over currently available scales are unlikely to achieve this. However, there remains a large region of parameter space (especially when considering the running of the running) for falsifying the assumed class of slow-roll models if future observations accurately constrain a much wider range of scales.

  12. Slow journalism in the “infoxication” era

    Directory of Open Access Journals (Sweden)

    Samia Benaissa Pedriza

    2017-11-01

    Full Text Available Slow journalism appears as a response to the information overload generated by the acceleration of the news production cycle in a digital era marked by the emergence of new operators (social networks, news aggregators. Both the study of cases practiced and the reflection on the function that the so-called “slow journalism” must exert today indicate that this type of journalism is still useful to improve the quality of information products. On the other hand, the existence of an increasing demand of multimedia contents that analyze the facts in depth is confirmed. That need is being covered by companies that are independent of the mainstream media, which are more interested in developing other mass demand markets such as latest news.

  13. Slow Controls Using the Axiom M5235BCC

    Science.gov (United States)

    Hague, Tyler

    2008-10-01

    The Forward Vertex Detector group at PHENIX plans to adopt the Axiom M5235 Business Card Controller for use as slow controls. It is also being evaluated for slow controls on FermiLab e906. This controller features the Freescale MCF5235 microprocessor. It also has three parallel buses, these being the MCU port, BUS port, and enhanced Time Processing Unit (eTPU) port. The BUS port uses a chip select module with three external chip selects to communicate with peripherals. This will be used to communicate with and configure Field Programmable Gate Arrays (FPGAs). The controller also has an Ethernet port which can use several different protocols such as TCP and UDP. This will be used to transfer files with computers on a network. The M5235 Business Card Controller will be placed in a VME crate along with VME card and a Spartan-3 FPGA.

  14. Investigation and realization of a slow-positron beam

    International Nuclear Information System (INIS)

    Ruiz, Nicolas

    2011-01-01

    This research thesis first proposes a presentation of the GBAR project (Gravitational Behaviour of Anti-hydrogen at Rest) within which this research took place, and which aims at performing the first direct test of the Weak Equivalence Principle on anti-matter by studying the free fall of anti-hydrogen atoms in the Earth gravitational field. The author presents different aspects of this project: scientific objective, experiment principle and structure, detailed structure (positron beam, positron trap, positron/positronium conversion, anti-proton beam, trapping, slowing down and neutralisation of anti-hydrogen ions). The author then reports the design of the positron beam: study of source technology, studies related to the fast positron source, design of the low positron line (approach, functions, simulations, technology). The two last chapters report the construction and the characterization of the slow-positron line [fr

  15. The phase transition to slow-roll eternal inflation

    International Nuclear Information System (INIS)

    Creminelli, P.; Dubovsky, S.; Nicolis, A.; Senatore, L.; Zaldarriaga, M.

    2008-01-01

    For slow-roll inflation we study the phase transition to the eternal regime. Starting from a finite inflationary volume, we consider the volume of the universe at reheating as order parameter. We show that there exists a critical value for the classical inflation speed, φ-dot 2 /H 4 = 3/(2 π 2 ), where the probability distribution for the reheating volume undergoes a sharp transition. In particular, for sub-critical inflation speeds all distribution moments become infinite. We show that at the same transition point the system develops a non-vanishing probability of having a strictly infinite reheating volume, while retaining a finite probability for finite values. Our analysis represents the exact quantum treatment of the system at lowest order in the slow-roll parameters and H 2 /M Pl 2 . (author)

  16. Overall concepts for utilisation of slow pyrolysis products - Hidaspyro II

    Energy Technology Data Exchange (ETDEWEB)

    Fagernas, L. [VTT Technical Research Centre of Finland, Espoo (Finland)], email: leena.fagernas@vtt.fi

    2012-07-01

    Slow pyrolysis is a promising technology to produce biochar (charcoal), distillates and gases for various purposes. However, scientific results on the effects of distillates and biochar on soil improvement are lacking, process conditions to produce biochar of good quality and optimal distillates are not known, and non-existence of environmental risks has to be proved prior to commercialization of the products. The goal is an optimised slow pyrolysis process for new applications of the products. The research carried out in the project Hidaspyro will be continued. The objectives are to determine the effect of biochar and distillates on growth of plants, soil improvement, and odour prevention; to define the quality criteria of biochar in plant production; and to assess the ecotoxicological and environmental impacts of the products.

  17. Systematic design of loss-engineered slow-light waveguides

    DEFF Research Database (Denmark)

    Wang, Fengwen; Jensen, Jakob Søndergaard; Mørk, Jesper

    2012-01-01

    This paper employs topology optimization to systematically design free-topology loss-engineered slow-light waveguides with enlarged group index bandwidth product (GBP). The propagation losses of guided modes are evaluated by the imaginary part of eigenvalues in complex band structure calculations......, where the scattering losses due to manufacturing imperfections are represented by an edge-related effective dissipation. The loss engineering of slow-light waveguides is realized by minimizing the propagation losses of design modes. Numerical examples illustrate that the propagation losses of free......-topology dispersion-engineered waveguides can be significantly suppressed by loss engineering. Comparisons between fixed- and free-topology loss-engineered waveguides demonstrate that the GBP can be enhanced significantly by the free-topology loss-engineered waveguides with a small increase of the propagation losses....

  18. Slow-light-enhanced gain in active photonic crystal waveguides

    DEFF Research Database (Denmark)

    Ek, Sara; Hansen, Per Lunnemann; Chen, Yaohui

    2014-01-01

    Passive photonic crystals have been shown to exhibit a multitude of interesting phenomena, including slow-light propagation in line-defect waveguides. It was suggested that by incorporating an active material in the waveguide, slow light could be used to enhance the effective gain of the material......, which would have interesting application prospects, for example enabling ultra-compact optical amplifiers for integration in photonic chips. Here we experi- mentally investigate the gain of a photonic crystal membrane structure with embedded quantum wells. We find that by solely changing the photonic...... crystal structural parameters, the maximum value of the gain coefficient can be increased compared with a ridge waveguide structure and at the same time the spectral position of the peak gain be controlled. The experimental results are in qualitative agreement with theory and show that gain values similar...

  19. Hamilton-Jacobi approach to non-slow-roll inflation

    International Nuclear Information System (INIS)

    Kinney, W.H.

    1997-01-01

    I describe a general approach to characterizing cosmological inflation outside the standard slow-roll approximation, based on the Hamilton-Jacobi formulation of scalar field dynamics. The basic idea is to view the equation of state of the scalar field matter as the fundamental dynamical variable, as opposed to the field value or the expansion rate. I discuss how to formulate the equations of motion for scalar and tensor fluctuations in situations where the assumption of slow roll is not valid. I apply the general results to the simple case of inflation from an open-quotes invertedclose quotes polynomial potential, and to the more complicated case of hybrid inflation. copyright 1997 The American Physical Society

  20. Direct imaging of slow, stored and stationary EIT polaritons

    Science.gov (United States)

    Campbell, Geoff T.; Cho, Young-Wook; Su, Jian; Everett, Jesse; Robins, Nicholas; Lam, Ping Koy; Buchler, Ben

    2017-09-01

    Stationary and slow light effects are of great interest for quantum information applications. Using laser-cooled Rb87 atoms, we performed side imaging of our atomic ensemble under slow and stationary light conditions, which allows direct comparison with numerical models. The polaritons were generated using electromagnetically induced transparency (EIT), with stationary light generated using counter-propagating control fields. By controlling the power ratio of the two control fields, we show fine control of the group velocity of the stationary light. We also compare the dynamics of stationary light using monochromatic and bichromatic control fields. Our results show negligible difference between the two situations, in contrast to previous work in EIT-based systems.

  1. A minimal model for a slow pacemaking neuron

    International Nuclear Information System (INIS)

    Zakharov, D.G.; Kuznetsov, A.

    2012-01-01

    Highlights: ► We have constructed a phenomenological model for slow pacemaking neurons. ► The model implements a nonlinearity introduced by an ion-dependent current. ► The new nonlinear dependence allows for differentiating responses to various stimuli. ► We discuss implications of our results for a broad class of neurons. - Abstract: We have constructed a phenomenological model for slow pacemaking neurons. These are neurons that generate very regular periodic oscillations of the membrane potential. Many of these neurons also differentially respond to various types of stimulation. The model is based on FitzHugh–Nagumo (FHN) oscillator and implements a nonlinearity introduced by a current that depends on an ion concentration. The comparison with the original FHN oscillator has shown that the new nonlinear dependence allows for differentiating responses to various stimuli. We discuss implications of our results for a broad class of neurons.

  2. Time coder for slow neutron time-of-flight spectrometer

    International Nuclear Information System (INIS)

    Grashilin, V.A.; Ofengenden, R.G.

    1988-01-01

    Time coder for slow neutron time-of-flight spectrometer is described. The time coder is of modular structure, is performed in the CAMAC standard and operates on line with DVK-2 computer. The main coder units include supporting generator, timers, time-to-digital converter, memory unit and crate controller. Method for measuring background symmetrically to the effect is proposed for a more correct background accounting. 4 refs.; 1 fig

  3. Developing organizational and learning skills of a slow learner

    OpenAIRE

    Mauko, Katja

    2016-01-01

    Slow learners are individuals with below average cognitive abilities. In general they are more immature and show problems in areas such as concentration, short-term and long-term memory, metacognition, motivation, social integration, executive functions and some others. One of the problematic areas is also organization. Well-developed organizational skills are very important because they affect many aspects of our lives. They enable us to cope with everyday tasks, as well as more complex task...

  4. Superintensive pulse slow neutron source SIN based on kaon factory

    International Nuclear Information System (INIS)

    Kolmichkov, N.V.; Laptev, V.D.; Matveev, V.A.

    1991-01-01

    Possibility of intensive pulse slow neutron source creation based on 45-GeV proton synchrotron of K-meson factory, planned to construction in INR AS USSR is considered. Calculated peak thermal neutrons flux density value, averaged on 'radiating' light-water moderator surface of 100 cm 2 is 6.6 x 10 17 neutrons/(cm 2 sec) for pulse duration of 35 microseconds. (author)

  5. Beyond the library walls: use of slow-scan television.

    OpenAIRE

    Lorenzi, N M; Kues, J R; Anthony, S S

    1984-01-01

    The Telecommunications Information Network (TIN) was an applied research project that evaluated the ability of slow-scan television to provide medical information on demand to health-care professionals at hospitals far from any urban area. This paper reviews the TIN project, describes its use, and discusses system advantages and disadvantages. System evaluation encompasses (1) project benefits; (2) technical barriers to implementation and utilization; (3) the replication of services and the t...

  6. Slow control systems of the Reactor Experiment for Neutrino Oscillation

    International Nuclear Information System (INIS)

    Choi, J.H.; Jang, H.I.; Choi, W.Q.; Choi, Y.; Jang, J.S.; Jeon, E.J.; Joo, K.K.; Kim, B.R.; Kim, H.S.; Kim, J.Y.; Kim, S.B.; Kim, S.Y.; Kim, W.; Kim, Y.D.; Ko, Y.J.; Lee, J.K.; Lim, I.T.; Pac, M.Y.; Park, I.G.; Park, J.S.

    2016-01-01

    The RENO experiment has been in operation since August 2011 to measure reactor antineutrino disappearance using identical near and far detectors. For accurate measurements of neutrino mixing parameters and efficient data taking, it is crucial to monitor and control the detector in real time. Environmental conditions also need to be monitored for stable operation of detectors as well as for safety reasons. In this paper, we report the design, hardware, operation, and performance of the slow control system.

  7. Cell proliferation of Paramecium tetraurelia on a slow rotating clinostat

    Science.gov (United States)

    Sawai, Satoe; Mogami, Yoshihiro; Baba, Shoji A.

    Paramecium is known to proliferate faster under microgravity conditions, and slower under hypergravity. Experiments using axenic culture medium have demonstrated that hypergravity affected directly on the proliferation of Paramecium itself. In order to assess the mechanisms underlying the physiological effects of gravity on cell proliferation, Paramecium tetraurelia was grown under clinorotation (2.5 rpm) and the time course of the proliferation was investigated in detail on the basis of the logistic analysis. On the basis of the mechanical properties of Paramecium, this slow rate of the rotation appears to be enough to simulate microgravity in terms of the randomization of the cell orientation with respect to gravity. P. tetraurelia was cultivated in a closed chamber in which cells were confined without air bubbles, reducing the shear forces and turbulences under clinorotation. The chamber is made of quartz and silicone rubber film; the former is for the optically-flat walls for the measurement of cell density by means of a non-invasive laser optical-slice method, and the latter for gas exchange. Because of the small dimension for culture space, Paramecium does not accumulate at the top of the chamber in spite of its known negative gravitactic behavior. We measured the cell density at regular time intervals without breaking the configuration of the chamber, and analyzed the proliferation parameters by fitting the data to a logistic equation. As a result, P. tetraurelia showed reduced proliferation under slow clinorotation. The saturation of the cell density as well as the maximum proliferation rate decreased, although we found no significant changes on the half maximal time for proliferation. We also found that the mean swimming velocity decreased under slow clinorotation. These results were not consistent with those under microgravity and fast rotating clinostat. This may suggest that randomization of the cell orientation performed by slow rotating clinostat has

  8. Proposal for an intense slow positron beam facility at PSI

    International Nuclear Information System (INIS)

    Waeber, W.B.; Taqqu, D.; Zimmermann, U.; Solt, G.

    1990-05-01

    In the domain of condensed matter physics and materials sciences monoenergetic slow positrons in the form of highest intensity beams are demonstrated to be extreamly useful and considered to be highly needed. This conclusion has been reached and the scientific relevance of the positron probe has been highlighted at an international workshop in November 1989 at PSI, where the state of the art and the international situation on slow positron beams, the fields of application of intense beams and the technical possibilities at PSI for installing intense positron sources have been evaluated. The participants agreed that a high intensity beam as a large-scale user facility at PSI would serve fundamental and applied research. The analysis of responses given by numerous members of a widespread positron community has revealed a large research potential in the domain of solid-state physics, atomic physics and surface, thin-film and defect physics, for example. The excellent feature of slow positron beams to be a suitable probe also for lattice defects near surfaces or interfaces has attracted the interest not only of science but also of industry.In this report we propose the installation of an intense slow positron beam facility at PSI including various beam lines of different qualities and based on the Cyclotron production of β + emitting source material and on a highest efficiency moderation scheme which exceeds standard moderation efficiencies by two orders of magnitude. In its proposed form, the project is estimated to be realizable in the nineties and costs will amount to between 15 and 20 MSFr. (author) 10 figs., 6 tabs., 78 refs

  9. Using Nonuniform Fiber to Generate Slow Light via SBS

    Directory of Open Access Journals (Sweden)

    Wenhai Li

    2008-01-01

    Full Text Available The data pulse delay based on slow light induced by stimulated Brillouin scattering (SBS in a nonuniform dispersion decreasing fiber (DDF is demonstrated experimentally, and the distortions of data pulses at different beat frequencies are studied. We found that a delay exceeding a pulse width can be achieved at particular beat frequency, and the DDF has larger delay versus gain slope coefficient with much better output pulse quality than single-mode fiber.

  10. Ponderomotive force effects on slow-wave coupling

    International Nuclear Information System (INIS)

    Wilson, J.R.; Wong, K.L.

    1982-01-01

    Localized plasma density depressions are observed to form near a multi-ring slow-wave structure when the value of the nonlinearity parameter, s = ω 2 /sub p/eVertical BarE/sub z/Vertical Bar 2 /8πω 2 nkappaT, is of order unity. Consequent changes in the wave propagation and coupling efficiency are reported. For large enough values of s, the coupling efficiency may be reduced by 50% from the linear value

  11. The Adaptive Organization and Fast-slow Systems

    DEFF Research Database (Denmark)

    Andersen, Torben Juul; Hallin, Carina Antonia

    2016-01-01

    Contemporary organizations operate under turbulent business conditions and must adapt their strategies to ongoing changes. This article argues that sustainable organizational performance is achieved when top management directs and coordinates interactive processes anchored in emerging...... organizational opportunities and forward-looking analytics. The fast and emergent processes performed by local managers at the frontline observe and respond to environmental stimuli and the slow processes initiated by decision makers interpret events and reasons about updated strategic actions. Current...

  12. Excitation of simple atoms by slow magnetic monopoles

    International Nuclear Information System (INIS)

    Kroll, N.M.; Parke, S.J.; Ganapathi, V.; Drell, S.D.

    1984-01-01

    We present a theory of excitation of simple atoms by slow moving massive monopoles. Previously presented results for a monopole of Dirac strength on hydrogen and helium are reviewed. The hydrogen theory is extended to include arbitrary integral multiples of the Dirac pole strength. The excitation of helium by double strength poles and by dyons is also discussed. It is concluded that a helium proportional counter is a reliable and effective detector for monopoles of arbitrary strength, and for negatively charged dyons

  13. Slowing the Next Pandemic: Survey of Community Mitigation Strategies

    Centers for Disease Control (CDC) Podcasts

    During the next influenza pandemic, it will take time to develop a vaccine and there may be limited medication to treat or prevent illness. To slow the spread of disease, CDC and other public health officials will likely ask Americans to decrease contact with others through altering work schedules, school dismissals and other measures. Researchers recently surveyed the public to see whether people could follow those recommendations and what kind of impact they might have.

  14. Constraint effect on the slow crack growth in polyethylene

    Czech Academy of Sciences Publication Activity Database

    Hutař, Pavel; Zouhar, Michal; Nezbedová, E.; Sadílek, J.; Žídek, J.; Náhlík, Luboš; Knésl, Zdeněk

    2012-01-01

    Roč. 2, č. 3 (2012), s. 118-126 ISSN 1757-9864 R&D Projects: GA ČR GD106/09/H035; GA ČR GA106/09/0279; GA ČR GC101/09/J027 Institutional support: RVO:68081723 Keywords : slow crack growth * polyethylene * constraint Subject RIV: JL - Materials Fatigue, Friction Mechanics

  15. Can power spectrum observations rule out slow-roll inflation?

    OpenAIRE

    Vieira, J. P. P.; Byrnes, Christian T.; Lewis, Antony

    2017-01-01

    The spectral index of scalar perturbations is an important observable that allows us to learn about inflationary physics. In particular, a detection of a significant deviation from a constant spectral index could enable us to rule out the simplest class of inflation models. We investigate whether future observations could rule out canonical single-field slow-roll inflation given the parameters allowed by current observational constraints. We find that future measurements of a constant running...

  16. Effective Fault-Tolerant Quantum Computation with Slow Measurements

    International Nuclear Information System (INIS)

    DiVincenzo, David P.; Aliferis, Panos

    2007-01-01

    How important is fast measurement for fault-tolerant quantum computation? Using a combination of existing and new ideas, we argue that measurement times as long as even 1000 gate times or more have a very minimal effect on the quantum accuracy threshold. This shows that slow measurement, which appears to be unavoidable in many implementations of quantum computing, poses no essential obstacle to scalability

  17. Slow decay of magnetic fields in open Friedmann universes

    International Nuclear Information System (INIS)

    Barrow, John D.; Tsagas, Christos G.

    2008-01-01

    Magnetic fields in Friedmann universes can experience superadiabatic growth without departing from conventional electromagnetism. The reason is the relativistic coupling between vector fields and spacetime geometry, which slows down the decay of large-scale magnetic fields in open universes, compared to that seen in perfectly flat models. The result is a large relative gain in magnetic strength that can lead to astrophysically interesting B fields, even if our Universe is only marginally open today

  18. Slow, Wet and Catalytic Pyrolysis of Fowl Manure

    OpenAIRE

    Renzo Carta; Mario Cruccu; Francesco Desogus

    2012-01-01

    This work presents the experimental results obtained at a pilot plant which works with a slow, wet and catalytic pyrolysis process of dry fowl manure. This kind of process mainly consists in the cracking of the organic matrix and in the following reaction of carbon with water, which is either already contained in the organic feed or added, to produce carbon monoxide and hydrogen. Reactions are conducted in a rotating reactor maintained at a temperature of 500°C; the requi...

  19. Slowing down of test particles in a plasma (1961)

    International Nuclear Information System (INIS)

    Belayche, P.; Chavy, P.; Dupoux, M.; Salmon, J.

    1961-01-01

    Numerical solution of the Fokker-Planck equation applied to the slowing down of tritons in a deuterium plasma. After the equations and the boundary conditions have been written, some attention is paid to the numerical tricks used to run the problem on a high speed electronic computer. The numerical results thus obtained are then analyzed and as far as possible, mathematically explained. (authors) [fr

  20. Slow ventricular response atrial fibrillation related to mad honey poisoning

    Science.gov (United States)

    Osken, A.; Yaylacı, S.; Aydın, E.; Kocayigit, İ; Cakar, M.A.; Tamer, A.; Gündüz, H.

    2012-01-01

    Mad honey poisoning which is induced by Grayanotoxin (Andromedotoxin), is also known to have adverse effects in the cardiovascular system leading to different clinical entities. This toxin is produced by a member of the Rhododendron genus of plants of two R. Luteum and R. Panticum. In this article, we presented a case of slow ventricular response atrial fibrillation complaints with nausea, vomiting, dizziness and chest pain about an hour after eating honey produced in the Black Sea Region. PMID:22923947

  1. Slow ventricular response atrial fibrillation related to mad honey poisoning

    OpenAIRE

    Osken, A.; Yaylacı, S.; Aydın, E.; Kocayigit, İ; Cakar, M.A.; Tamer, A.; Gündüz, H.

    2012-01-01

    Mad honey poisoning which is induced by Grayanotoxin (Andromedotoxin), is also known to have adverse effects in the cardiovascular system leading to different clinical entities. This toxin is produced by a member of the Rhododendron genus of plants of two R. Luteum and R. Panticum. In this article, we presented a case of slow ventricular response atrial fibrillation complaints with nausea, vomiting, dizziness and chest pain about an hour after eating honey produced in the Black Sea Region.

  2. Excited states in 22Mg via the 12C(12C,2n)22Mg reaction

    International Nuclear Information System (INIS)

    Jewett, Cybele; Baktash, Cyrus; Bardayan, Daniel W.; Blackmon, Jeff C.; Chipps, K.; Galindo-Uribarri, Alfredo; Greife, U.; Gross, Carl J.; Jones, K. L.; Liang, Junjien; Livesay, Jake; Kozub, R. L.; Nesaraja, Caroline D; Radford, David C.; Sarazin, F.; Smith, Michael Scott; Thomas, J. S.; Yu, Chang-Hong

    2007-01-01

    The 12C(12C, 2n)22Mg reaction was measured with the CLARION array and the RMS separator at the Holifield Facility of Oak Ridge National Laboratory. This experiment was performed to gather more information on the excited states in 22Mg, which might be of relevance to recent radioactive ion beam measurements of the astrophysically important 21Na(p,γ)22Mg reaction. The results are compared to direct measurements, transfer experiments and a competing experiment performed with Gammasphere

  3. Mifepristone 5 mg versus 10 mg for emergency contraception: double-blind randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Carbonell JL

    2015-01-01

    Full Text Available Josep Lluis Carbonell,1 Ramon Garcia,2 Adriana Gonzalez,2 Andres Breto,2 Carlos Sanchez2 1Mediterranea Medica Clinic, Valencia, Spain; 2Eusebio Hernandez Gynecology and Obstetrics Teaching Hospital, Havana, Cuba Purpose: To estimate the efficacy and safety of 5 mg and 10 mg mifepristone for emergency contraception up to 144 hours after unprotected coitus. Methods: This double-blind randomized clinical trial was carried out at Eusebio Hernandez Hospital (Havana, Cuba. A total of 2,418 women who requested emergency contraception after unprotected coitus received either 5 mg or 10 mg mifepristone. The variables for assessing efficacy were the pregnancies that occurred and the fraction of pregnancies that were prevented. Other variables assessed were the side effects of mifepristone, vaginal bleeding, and changes in the date of the following menstruation. Results: There were 15/1,206 (1.2% and 9/1,212 (0.7% pregnancies in the 5 mg and 10 mg group, respectively (P=0.107. There were 88% and 93% prevented pregnancies in the 5 mg and 10 mg group, respectively. The side effect profiles were similar in both groups. Delayed menstruation ≥7 days was experienced by 4.9% and 11.0% of subjects in the 5 mg and 10 mg group, respectively (P=0.001. There was a significant high failure rate for women weighing >75 kg in the 5 mg group. Conclusion: It would be advisable to use the 10 mg dose of mifepristone for emergency contraception as there was a trend suggesting that the failure rate of the larger dose was lower. Keywords: mifepristone, emergency contraception

  4. Potential sustainable slow release fertilizers obtained by mechanochemical activation of layered double hydroxides and K{sub 2}HPO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Roger; Wypych, Fernando, E-mail: 1roger.borges@gmail.com [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Prevot, Vanessa; Forano, Claude [Universite Blaise Pascal, Clermont-Ferrand (France)

    2016-07-01

    Full text: This study describes the preliminary results on the development of potential sustainable slow-release fertilizer (SSRF), obtained by mechanochemical activation of mixtures of calcined layered double hydroxides (LDH) Mg{sub 2}Al-CO{sub 3} and Mg{sub 2}Fe-CO{sub 3} and K{sub 2}HPO{sub 4}. The effect of LDH temperature of calcination, milling time (using a high-energy balls mill) and LDH:K{sub 2}HPO{sub 4} molar were investigated. The samples were characterized by XRD and FTIR. Phosphate release essays shown that its solubility is reduced, while the solubility of amorphous structures from LDH can be increased, which characterize the expected slow release behavior of a SSRF. (author)

  5. Sevoflurane Induces Coherent Slow-Delta Oscillations in Rats

    Directory of Open Access Journals (Sweden)

    Jennifer A. Guidera

    2017-07-01

    Full Text Available Although general anesthetics are routinely administered to surgical patients to induce loss of consciousness, the mechanisms underlying anesthetic-induced unconsciousness are not fully understood. In rats, we characterized changes in the extradural EEG and intracranial local field potentials (LFPs within the prefrontal cortex (PFC, parietal cortex (PC, and central thalamus (CT in response to progressively higher doses of the inhaled anesthetic sevoflurane. During induction with a low dose of sevoflurane, beta/low gamma (12–40 Hz power increased in the frontal EEG and PFC, PC and CT LFPs, and PFC–CT and PFC–PFC LFP beta/low gamma coherence increased. Loss of movement (LOM coincided with an abrupt decrease in beta/low gamma PFC–CT LFP coherence. Following LOM, cortically coherent slow-delta (0.1–4 Hz oscillations were observed in the frontal EEG and PFC, PC and CT LFPs. At higher doses of sevoflurane sufficient to induce loss of the righting reflex, coherent slow-delta oscillations were dominant in the frontal EEG and PFC, PC and CT LFPs. Dynamics similar to those observed during induction were observed as animals emerged from sevoflurane anesthesia. We conclude that the rat is a useful animal model for sevoflurane-induced EEG oscillations in humans, and that coherent slow-delta oscillations are a correlate of sevoflurane-induced behavioral arrest and loss of righting in rats.

  6. Nitrous oxide-induced slow and delta oscillations.

    Science.gov (United States)

    Pavone, Kara J; Akeju, Oluwaseun; Sampson, Aaron L; Ling, Kelly; Purdon, Patrick L; Brown, Emery N

    2016-01-01

    Switching from maintenance of general anesthesia with an ether anesthetic to maintenance with high-dose (concentration >50% and total gas flow rate >4 liters per minute) nitrous oxide is a common practice used to facilitate emergence from general anesthesia. The transition from the ether anesthetic to nitrous oxide is associated with a switch in the putative mechanisms and sites of anesthetic action. We investigated whether there is an electroencephalogram (EEG) marker of this transition. We retrospectively studied the ether anesthetic to nitrous oxide transition in 19 patients with EEG monitoring receiving general anesthesia using the ether anesthetic sevoflurane combined with oxygen and air. Following the transition to nitrous oxide, the alpha (8-12 Hz) oscillations associated with sevoflurane dissipated within 3-12 min (median 6 min) and were replaced by highly coherent large-amplitude slow-delta (0.1-4 Hz) oscillations that persisted for 2-12 min (median 3 min). Administration of high-dose nitrous oxide is associated with transient, large amplitude slow-delta oscillations. We postulate that these slow-delta oscillations may result from nitrous oxide-induced blockade of major excitatory inputs (NMDA glutamate projections) from the brainstem (parabrachial nucleus and medial pontine reticular formation) to the thalamus and cortex. This EEG signature of high-dose nitrous oxide may offer new insights into brain states during general anesthesia. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  7. A review of slow-release fluoride devices.

    Science.gov (United States)

    Toumba, K J; Al-Ibrahim, N S; Curzon, M E J

    2009-09-01

    Fluoride has been used to combat dental caries using a number of different clinical approaches. An exciting relatively new development is fluoride slow-releasing devices that consistently elevate intra-oral fluoride levels of plaque and saliva for prolonged periods of up to two years. The literature on the use of slow-releasing fluoride devices in dentistry were reviewed. A Medline search on key words was carried out. All papers in English were individually reviewed. Slow-releasing fluoride devices have been shown to be effective in elevating salivary fluoride levels in both animals and human studies and to enhance the remineralisation of dental enamel. They have been demonstrated to be safe to use and without the risk of fluoride toxicity. A double blind randomised clinical trial demonstrated 76% fewer new carious surface increment in high caries-risk children after two years. These devices have a number of potential uses in dentistry and in particular have great potential for caries prevention of non-compliant high caries-risk groups.

  8. Slow Motion and Zoom in HD Digital Videos Using Fractals

    Directory of Open Access Journals (Sweden)

    Maurizio Murroni

    2009-01-01

    Full Text Available Slow motion replay and spatial zooming are special effects used in digital video rendering. At present, most techniques to perform digital spatial zoom and slow motion are based on interpolation for both enlarging the size of the original pictures and generating additional intermediate frames. Mainly, interpolation is done either by linear or cubic spline functions or by motion estimation/compensation which both can be applied pixel by pixel, or by partitioning frames into blocks. Purpose of this paper is to present an alternative technique combining fractals theory and wavelet decomposition to achieve spatial zoom and slow motion replay of HD digital color video sequences. Fast scene change detection, active scene detection, wavelet subband analysis, and color fractal coding based on Earth Mover's Distance (EMD measure are used to reduce computational load and to improve visual quality. Experiments show that the proposed scheme achieves better results in terms of overall visual quality compared to the state-of-the-art techniques.

  9. Critical slowing down and error analysis in lattice QCD simulations

    International Nuclear Information System (INIS)

    Virotta, Francesco

    2012-01-01

    In this work we investigate the critical slowing down of lattice QCD simulations. We perform a preliminary study in the quenched approximation where we find that our estimate of the exponential auto-correlation time scales as τ exp (a)∝a -5 , where a is the lattice spacing. In unquenched simulations with O(a) improved Wilson fermions we do not obtain a scaling law but find results compatible with the behavior that we find in the pure gauge theory. The discussion is supported by a large set of ensembles both in pure gauge and in the theory with two degenerate sea quarks. We have moreover investigated the effect of slow algorithmic modes in the error analysis of the expectation value of typical lattice QCD observables (hadronic matrix elements and masses). In the context of simulations affected by slow modes we propose and test a method to obtain reliable estimates of statistical errors. The method is supposed to help in the typical algorithmic setup of lattice QCD, namely when the total statistics collected is of O(10)τ exp . This is the typical case when simulating close to the continuum limit where the computational costs for producing two independent data points can be extremely large. We finally discuss the scale setting in N f =2 simulations using the Kaon decay constant f K as physical input. The method is explained together with a thorough discussion of the error analysis employed. A description of the publicly available code used for the error analysis is included.

  10. Anismus in patients with normal and slow transit constipation.

    Science.gov (United States)

    Miller, R; Duthie, G S; Bartolo, D C; Roe, A M; Locke-Edmunds, J; Mortensen, N J

    1991-06-01

    This study examined differences in anorectal function, with particular reference to anismus, which might explain why some patients with intractable constipation have slow and others have normal whole gut transit times. Twenty-four patients were studied; 13 with slow transit (all female, median age 32 years, range 16-52 years) and 11 with normal transit (eight women, three men, median age 37 years, range 21-60 years). Videoproctography with synchronous sphincteric electromyography and anorectal manometry was performed. There were no differences between the two groups, suggesting that slow transit constipation is not secondary to any abnormality in anorectal function and may therefore be a primary disorder of colonic motility. There was no correlation between electromyographic evidence of anismus (pelvic floor contraction on defaecation) and the ability of the patient to evacute the rectum or symptoms of obstructed defaecation. Electromyography findings alone can be misleading and should be related to proctographic evidence of incomplete rectal evacuation before functional anismus can be said to be present.

  11. 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

  12. Slow magnetic monopoles search in NOvA

    Science.gov (United States)

    Antoshkin, Alexander; Frank, Martin

    2018-04-01

    The NOvA far detector is well suited for finding exotic particles due to its technical features (see [1]). One type of those exotic particles is a "slow" magnetic monopole. It is assumed that the energy deposition of such monopoles should be enough to be registered (see [2]). Measurement of the expected signals was performed on the NOvA test bench at JINR (see [3]). Result of this measurement allows us to perform slow monopole's research using NOvA software and hardware with high efficiency. As a whole, the research can lead to a discovery, or it can limit the existence of monopoles in a wide range of parameters, previously unreachable in other experiments (MACRO, SLIM, RICE, IceCube). Several special software tools have been developed. Slow Monopole Trigger has been created and implemented in the NOvA Data-Driven-Trigger system. Also, an online reconstruction algorithm has been developed and tested on 5% of the data. A technical description of these tools and current results of the analysis are presented in this work.

  13. Multisteps Global Kinetic Analysis of MSW Slow Pyrolysis

    Directory of Open Access Journals (Sweden)

    Dwi Aries Himawanto

    2013-12-01

    Full Text Available The goal of this research is to find relationships between single components slow pyrolysis characteristics and mixed component slow pyrolysis characteristics of segregated municipal solid wastes (MSW. The material of this research consists of organic wastes (bamboo wastes and banana leaves wastes and inorganic wastes (styrofoam wastes and snack wrapping wastes. The materials which used to study were the unprosessing waste. The samples were collected, dried and crushed until passing 20 mesh shieves then characterized in self manufactured macro balance. The thermogravimetry analyses were done to find the MSW slow pyrolysis characteristics. The 20 gram sample was placed in the furnace whose temperature is increased with 10 0C/min heating rate until reached 400 0 final temperature and held for 30 minutes before the sample is cooled into room temperature. One hundred ml/min nitrogen introduced from the bottom of furnace as a swept gas. The results of the research show that the global kinetic method could be used to predict the MSW single component activation energy but it should be modified to calculate the mixed sample activation energy . The predictive activation energy values which calculated based on weighed sum of single component have 18.5 % deviations if compared with experimental result.

  14. Nonhuman primates prefer slow tempos but dislike music overall.

    Science.gov (United States)

    McDermott, Josh; Hauser, Marc D

    2007-09-01

    Human adults generally find fast tempos more arousing than slow tempos, with tempo frequently manipulated in music to alter tension and emotion. We used a previously published method [McDermott, J., & Hauser, M. (2004). Are consonant intervals music to their ears? Spontaneous acoustic preferences in a nonhuman primate. Cognition, 94(2), B11-B21] to test cotton-top tamarins and common marmosets, two new-World primates, for their spontaneous responses to stimuli that varied systematically with respect to tempo. Across several experiments, we found that both tamarins and marmosets preferred slow tempos to fast. It is possible that the observed preferences were due to arousal, and that this effect is homologous to the human response to tempo. In other respects, however, these two monkey species showed striking differences compared to humans. Specifically, when presented with a choice between slow tempo musical stimuli, including lullabies, and silence, tamarins and marmosets preferred silence whereas humans, when similarly tested, preferred music. Thus despite the possibility of homologous mechanisms for tempo perception in human and nonhuman primates, there appear to be motivational ties to music that are uniquely human.

  15. Proposal for a slow positron facility at Jefferson National Laboratory

    Science.gov (United States)

    Mills, Allen P.

    2018-05-01

    One goal of the JPos-17 International Workshop on Physics with Positrons was to ascertain whether it would be a good idea to expand the mission of the Thomas Jefferson National Accelerator Facility (JLab) to include science with low energy (i.e. "slow") spin polarized positrons. It is probably true that experimentation with slow positrons would potentially have wide-ranging benefits comparable to those obtained with neutron and x-ray scattering, but it is certain that the full range of these benefits will never be fully available without an infrastructure comparable to that of existing neutron and x-ray facilities. The role for Jefferson Laboratory would therefore be to provide and maintain (1) a dedicated set of machines for making and manipulating high intensity, high brightness beams of polarized slow positrons; (2) a suite of unique and easily used instruments of wide utility that will make efficient use of the positrons; and (3) a group of on-site positron scientists to provide scientific leadership, instrument development, and user support. In this note some examples will be given of the science that might make a serious investment in a positron facility worthwhile. At the same time, the lessons learned from various proposed and successful positron facilities will be presented for consideration.

  16. Overall concepts for utilisation of slow pyrolysis products - Hidaspyro II

    Energy Technology Data Exchange (ETDEWEB)

    Fagernaes, L.; Kuoppala, E.; Ranta, J. (VTT Technical Research Centre of Finland, Espoo (Finland)), e-mail: leena.fagernas@vtt.fi; Setaelae, H.; Hagner, M. (University of Helsinki, Lahti (Finland), Dept. of Ecological and Environmental Sciences), e-mail: heikki.setala@helsinki.fi; Tiilikkala, K.; Palojaervi, A.; Lindqvist, B. (MTT Agrifood Research Finland, Jokioinen (Finland)), e-mail: kari.tiilikkala@mtt.fi

    2011-11-15

    The project aims at developing new distributed biorefineries and comprehensive concepts based on slow pyrolysis for SMEs. The research carried out in the project 'Hidaspyro' will be continued in the new project. The goal is an optimised slow pyrolysis process for new applications of the products. The objective is to determine the effects of biochar and distillates on growth of plants, soil improvement, carbon sequestration and emissions of cultivation, to define the quality criteria of biochar, to determine the potential of distillates in odour prevention and to assess the environmental impacts of the products. Optimal process parameters to produce distillates and biochar of high quality will be determined by well-controlled laboratory-scale slow pyrolysis testing facility to be constructed. The main feedstock material will be birchwood, but comparisons with other biomass feedstocks will also be carried out. The efficacy tests will show the effect of biochars and distillates on growth of plants, use of water and nutrients, and biological activity of soil. Demonstrations of soil improvement and odour prevention will be done in co-operation with the partner enterprises. The environmental effects of different biochars will be compared by following the changes in the activity of microbes and the composition of nematode community. The amount and quality of distillate and biochar safe to the environment will be defined. All the results will be utilised in the techno-economic assessment of different concepts. (orig.)

  17. Superconducting properties of MgB2 particle impregnated with Mg-based alloys

    International Nuclear Information System (INIS)

    Shimizu, Yusuke; Matsuda, Kenji; Mizutani, Manabu; Nishimura, Katsuhiko; Kawabata, Tokimasa; Ikeno, Susumu; Hishinuma, Yoshimitsu; Aoyama, Shigeki

    2011-01-01

    The three-dimensional penetration method combined with semi-solid casting (SS-3DPC) was utilized to prepare magnesium diboride (MgB 2 ) powder composite materials with various host materials of Mg, Mg-3%Al, Mg-3%Al-1%Zn, Mg-9%Al, and Mg-9%Al-1%Zn. X-ray diffraction measurements indicated predominant peak patterns of MgB 2 and a host alloy, implying that the host material tightly bonded MgB 2 grains without melting the MgB 2 powder. This was confirmed by SEM images. Measured electrical resistivity and magnetization versus temperature showed clear signals of superconducting transition temperature of 27-38 K for all the samples cut out from the billets. Magnetic hysteresis loop observed at 5 K enabled us to estimate a critical current density (J c ) based on the extended Bean model. Additions of aluminum and zinc elements to magnesium host-matrix were found to enhance J c and increase residual resistivity (ρ 0 ) suggesting that aluminum and zinc have an effect on pinning magnetic flux flow for J c enhancement, and scattering conduction electrons for increase of ρ 0 . (author)

  18. Slow-mode degradation mechanism and its control in new bright and long-lived ZnSe white LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Masahiro [Venture Business Laboratory, Tottori University, 4-101 Koyama-Minami, Tottori 680-8552 (Japan); Ando, Koshi; Abe, Tomoki; Inoue, Noboru; Urata, Akihiro; Tsutsumi, Sueyuki; Hashimoto, Yutaka; Kasada, Hirofumi [Electrical and Electronic Department, Tottori University, 4-101 Koyama-Minami, Tottori 680-8552 (Japan); Katayama, Koji; Nakamura, Takao [Semiconductor Technologies R and D Laboratories, Sumitomo Electric Industries Ltd., 1-1-1 Koyakita, Itami, Hyogo, 665-0016 (Japan)

    2006-03-15

    This paper presents slow-mode degradation mechanism of ZnSe-based white LEDs. A systematic study has been made from a viewpoint of microscopic point defect reaction such as generation and migration in both device active layer (ZnCdSe/ZnSe MQW) and p-type ZnMgSSe cladding layer utilizing DLTS/ ICTS, SSRM (scanning spreading resistance microscope), and EL (electroluminescence)-imaging techniques, coupled with device aging experiments. We have found two different degradation stages (1st and 2nd stages) in the slow-mode degradation, which are caused by quite different microscopic point defect species. The 1st stage is induced by the long-diffusion of H0-center (nitrogen-complex deep hole trap in p-cladding layer), forming high-density dark-spots in the MQW active layer. This active center is generated only in the stress-stimulated condition such as thermal or device fabrication process. After controlling the initial concentration of the H0 center, we have observed no detectable new dark-spots during device operation, leading to fairly long device-lifetime ({proportional_to}1000 h). This 2nd stage has appeared as a carrier (hole) reduction in the p-type cladding layer. This final degradation stage is found to take place by an increase of shallow compensating donor-like centers in p-type cladding layer (ZnMgSSe). Based on these insights on the microscopic point defect reaction, we have developed (new) double cladding i-ZnMgBeSe/p-ZnMgSSe white-LEDs, which has exhibited long device lifetime of over 10000 h. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Electronic structure of MgB2

    Indian Academy of Sciences (India)

    Abstract. Results of ab initio electronic structure calculations on the compound MgB2 using the. FPLAPW method employing GGA for the exchange-correlation energy are presented. Total energy minimization enables us to estimate the equilibrium volume, c/a ratio and the bulk modulus, all of which are in excellent ...

  20. Electronic structure of MgB 2

    Indian Academy of Sciences (India)

    Results of ab initio electronic structure calculations on the compound MgB2 using the FPLAPW method employing GGA for the exchange-correlation energy are presented. Total energy minimization enables us to estimate the equilibrium volume, / ratio and the bulk modulus, all of which are in excellent agreement with ...