Peripheral metabolism of (R)-[11C]verapamil in epilepsy patients

International Nuclear Information System (INIS)

Abrahim, Aiman; Langer, Oliver; Luurtsema, Gert; Lubberink, Mark; Lammertsma, Adriaan A.; Bauer, Martin; Joukhadar, Christian; Mueller, Markus; Karch, Rudolf; Pataraia, Ekaterina; Baumgartner, Christoph; Kletter, Kurt

2008-01-01

(R)-[ 11 C]verapamil is a new PET tracer for P-glycoprotein-mediated transport at the blood-brain barrier. For kinetic analysis of (R)-[ 11 C]verapamil PET data the measurement of a metabolite-corrected arterial input function is required. The aim of this study was to assess peripheral (R)-[ 11 C]verapamil metabolism in patients with temporal lobe epilepsy and compare these data with previously reported data from healthy volunteers. Arterial blood samples were collected from eight patients undergoing (R)-[ 11 C]verapamil PET and selected samples were analysed for radiolabelled metabolites of (R)-[ 11 C]verapamil by using an assay that measures polar N-demethylation metabolites by solid-phase extraction and lipophilic N-dealkylation metabolites by HPLC. Peripheral metabolism of (R)-[ 11 C]verapamil was significantly faster in patients compared to healthy volunteers (AUC of (R)-[ 11 C]verapamil fraction in plasma: 29.4 ± 3.9 min for patients versus 40.8 ± 5.0 min for healthy volunteers; p 11 C]verapamil plasma concentrations (AUC of (R)-[ 11 C]verapamil concentration, normalised to injected dose per body weight: 25.5 ± 2.1 min for patients and 30.5 ± 5.9 min for healthy volunteers; p = 0.038). Faster metabolism appeared to be mainly due to increased N-demethylation as the polar [ 11 C]metabolite fraction was up to two-fold greater in patients. Faster metabolism of (R)-[ 11 C]verapamil in epilepsy patients may be caused by hepatic cytochrome P450 enzyme induction by antiepileptic drugs. Based on these data caution is warranted when using an averaged arterial input function derived from healthy volunteers for the analysis of patient data. Moreover, our data illustrate how antiepileptic drugs may decrease serum levels of concomitant medication, which may eventually lead to a loss of therapeutic efficacy. (orig.)

Verapamil for cluster headache. Clinical pharmacology and possible mode of action

DEFF Research Database (Denmark)

Tfelt-Hansen, Peer; Tfelt-Hansen, Jacob

2009-01-01

is therefore limited. The clinical use of verapamil in cluster headache is reviewed and several relevant drug interactions are mentioned. Finally, its possible mode of action in cluster headache is discussed. The effect of verapamil in cluster headache most likely takes place in the hypothalamus......Verapamil is used mainly in cardiovascular diseases. High-dose verapamil (360-720 mg) is, however, currently the mainstay in the prophylactic treatment of cluster headache. The oral pharmacokinetics are variable. The pharmacodynamic effect of verapamil, the effect on blood pressure, also varies.......Verapamil is an L-type calcium channel blocker but it is also a blocker of other calcium channels (T-, P-, and possibly N- and Q-type Ca(2+) channels) and the human ether-a-go-go-related gene potassium channel. With so many different actions of verapamil, it is impossible at the present time to single out a certain...

Pharmaceutical Factors Affecting The Formulation Of Verapamil HCl ...

African Journals Online (AJOL)

Floating sustained release Verapamil HCl capsules were prepared using different polymers. Hydroxypropylmethyl cellulose 4000 and 50 (HPMC 4000 & HPMC 50), Carbopol 934, sodium alginate (Na alginate), carboxymethyl cellulose (CMC) and Pectin were used to study their effect on the release of Verapamil HCl from ...

Internal bremsstrahlung from 89Sr and 90Sr

International Nuclear Information System (INIS)

Sayibaba, T.; Narasimha Murity, K.; Rao, C.R.; Satyaprakash; Gubbi, G.K.

1987-01-01

The internal bremsstrahlung (IB) spectra emitted in the beta-decays of 89 Sr and 90 Sr were measured with a HPGe detector and a multichannel analyser along with a standard geometrical set-up. Sufficient care has been taken to avoid spurious effects. After making all the necessary corrections, the experimental results were compared with the corresponding theoretical distributions due to Knipp and Uhlenbeck and Bloch (KUB), Lewis and Ford, Nilsson, and also due to Ford and Martin (detour theory). The total IB yields of intensity and energy from each of the isotopes in the investigated energy regions are also determined and compared with the corresponding theoretical values. The present results of IB from 89 Sr are satisfactorily accounted for by the KUB theory. In the case of 90 Sr the experimental results of IB coincide with the Coulomb-corrected theoretical distibution due to Nilsson in the energy range from 60 keV to 110 keV and Beyond 110 keV, they are found to be in excess over Nilsson's theory as well as the detour theory due to Ford and Martin up to the maximum photon energy studied, namely 350 keV

Peripheral metabolism of (R)-[{sup 11}C]verapamil in epilepsy patients

Energy Technology Data Exchange (ETDEWEB)

Abrahim, Aiman; Langer, Oliver [Medical University of Vienna, Department of Clinical Pharmacology, Division of Clinical Pharmacokinetics, Vienna (Austria); Austrian Research Centers GmbH - ARC, Department of Radiopharmaceuticals, Seibersdorf (Austria); Luurtsema, Gert; Lubberink, Mark; Lammertsma, Adriaan A. [VU University Medical Centre, Department of Nuclear Medicine and PET Research, Amsterdam (Netherlands); Bauer, Martin; Joukhadar, Christian; Mueller, Markus [Medical University of Vienna, Department of Clinical Pharmacology, Division of Clinical Pharmacokinetics, Vienna (Austria); Karch, Rudolf [Medical University of Vienna, Department of Medical Computer Sciences, Vienna (Austria); Pataraia, Ekaterina; Baumgartner, Christoph [Medical University of Vienna, Department of Neurology, Vienna (Austria); Kletter, Kurt [Medical University of Vienna, Department of Nuclear Medicine, Vienna (Austria)

2008-01-15

(R)-[{sup 11}C]verapamil is a new PET tracer for P-glycoprotein-mediated transport at the blood-brain barrier. For kinetic analysis of (R)-[{sup 11}C]verapamil PET data the measurement of a metabolite-corrected arterial input function is required. The aim of this study was to assess peripheral (R)-[{sup 11}C]verapamil metabolism in patients with temporal lobe epilepsy and compare these data with previously reported data from healthy volunteers. Arterial blood samples were collected from eight patients undergoing (R)-[{sup 11}C]verapamil PET and selected samples were analysed for radiolabelled metabolites of (R)-[{sup 11}C]verapamil by using an assay that measures polar N-demethylation metabolites by solid-phase extraction and lipophilic N-dealkylation metabolites by HPLC. Peripheral metabolism of (R)-[{sup 11}C]verapamil was significantly faster in patients compared to healthy volunteers (AUC of (R)-[{sup 11}C]verapamil fraction in plasma: 29.4 {+-} 3.9 min for patients versus 40.8 {+-} 5.0 min for healthy volunteers; p < 0.0005, Student's t-test), which resulted in lower (R)-[{sup 11}C]verapamil plasma concentrations (AUC of (R)-[{sup 11}C]verapamil concentration, normalised to injected dose per body weight: 25.5 {+-} 2.1 min for patients and 30.5 {+-} 5.9 min for healthy volunteers; p = 0.038). Faster metabolism appeared to be mainly due to increased N-demethylation as the polar [{sup 11}C]metabolite fraction was up to two-fold greater in patients. Faster metabolism of (R)-[{sup 11}C]verapamil in epilepsy patients may be caused by hepatic cytochrome P450 enzyme induction by antiepileptic drugs. Based on these data caution is warranted when using an averaged arterial input function derived from healthy volunteers for the analysis of patient data. Moreover, our data illustrate how antiepileptic drugs may decrease serum levels of concomitant medication, which may eventually lead to a loss of therapeutic efficacy. (orig.)

Verapamil stereoisomers induce antiproliferative effects in vascular smooth muscle cells via autophagy

Energy Technology Data Exchange (ETDEWEB)

Salabei, Joshua K. [Diabetes and Obesity Center, University of Louisville, Louisville, KY 40202 (United States); Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY 40202 (United States); Balakumaran, Arun [Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States); Frey, Justin C. [Department of Biology, University of Wisconsin-Eau Claire, Eau Claire, WI 54702 (United States); Boor, Paul J. [Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States); Treinen-Moslen, Mary [Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555‐0609 (United States); Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States); Conklin, Daniel J., E-mail: dj.conklin@louisville.edu [Diabetes and Obesity Center, University of Louisville, Louisville, KY 40202 (United States); Division of Cardiovascular Medicine, University of Louisville, Louisville, KY 40202 (United States); Department of Biology, University of Wisconsin-Eau Claire, Eau Claire, WI 54702 (United States); Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States)

2012-08-01

Calcium channel blockers (CCBs) are important in the management of hypertension and limit restenosis. Although CCB efficacy could derive from decreased blood pressure, other mechanisms independent of CCB activity also can contribute to antiproliferative action. To understand mechanisms of CCB-mediated antiproliferation, we studied two structurally dissimilar CCBs, diltiazem and verapamil, in cultured rat vascular smooth muscle cells (VSMC). To elucidate CCB-independent effects, pure stereoisomers of verapamil (R-verapamil, inactive VR; S-verapamil, active, VS) were used. The effects of CCB exposure on cell viability (MTT reduction), cell proliferation ({sup 3}H-thymidine incorporation), VSMC morphology by light and transmission electron microscopy (TEM) and autophagy (LC3I/II, ATG5) were measured. In general, verapamil, VR or VS treatment alone (80 μM) appreciably enhanced MTT absorbance although higher concentrations (VR or VS) slightly decreased MTT absorbance. Diltiazem (140 μM) markedly decreased MTT absorbance (40%) at 120 h. VR or VS treatment inhibited {sup 3}H-thymidine incorporation (24 h) and induced cytological alterations (i.e., karyokinesis, enhanced perinuclear MTT deposition, accumulated perinuclear “vacuoles”). TEM revealed perinuclear “vacuoles” to be aggregates of highly laminated and electron-dense vesicles resembling autophagosomes and lysosomes, respectively. Increased autophagosome activity was confirmed by a concentration-dependent increase in LC3-II formation by Western blotting and by increased perinuclear LC3-GFP{sup +} puncta in verapamil-treated VSMC. Verapamil stereoisomers appeared to decrease perinuclear mitochondrial density. These observations indicate that antiproliferative effects of verapamil stereoisomers are produced by enhanced mitochondrial damage and upregulated autophagy in VSMC. These effects are independent of CCB activity indicating a distinct mechanism of action that could be targeted for more efficacious anti

Effect of angiotensin converting enzyme inhibition after acute myocardial infarction in patients with arterial hypertension. TRACE Study Group, Trandolapril Cardiac Event

DEFF Research Database (Denmark)

Gustafsson, F; Torp-Pedersen, C; Køber, L

1997-01-01

patients who entered the study, 400 (23%) had a history of arterial hypertension. The mean follow-up time was 26 months. MAIN OUTCOME MEASURES: Mortality from any cause. Secondary endpoints were sudden death, cardiovascular mortality, reinfarction and development of severe heart failure. RESULTS......OBJECTIVE: To evaluate the influence of a history of arterial hypertension on the efficacy of the angiotensin converting enzyme (ACE) inhibitor trandolapril in patients with acute myocardial infarction (AMI) and left ventricular dysfunction. METHODS: A retrospective analysis of data from......: Of the patients in the hypertensive group, 173 (43%) died during follow-up, versus 500 (37%) in the normotensive group. Treatment with trandolapril resulted in a relative risk of death from any cause for the hypertensive group of 0.59 (96% confidence interval 0.44-0.80), versus 0.85 (0.72-1.02) for normotensive...

A prospective, randomized, single - blind study comparing intraplaque injection of thiocolchicine and verapamil in Peyronie's Disease: a pilot study

Directory of Open Access Journals (Sweden)

I. L. Toscano Jr.

Full Text Available ABSTRACT Objectives: To compare the response to tiocolchicine and verapamil injection in the plaque of patients with Peyronie's disease. Materials and Methods: Prospective, single-blind, randomized study, selecting patients who have presented Peyronie's disease for less than 18 months. Thiocolchicine 4mg or verapamil 5mg were given in 7 injections (once a week. Patients who had received any treatment for Peyronie's disease in the past three months were excluded. The parameters used were the International Index of Erectile Function (IIEF-5 score, analysis of the curvature on pharmaco-induced erections and size of the plaque by ultrasonography. Results: Twenty-five patients were randomized, 13 received thiocolchicine and 12 were treated with verapamil. Both groups were statistically similar. The mean curvature was 46.7° and 36.2° before and after thiocolchicine, respectively (p=0.019 and 50.4° and 42.08° before and after verapamil, respectively (p=0.012. The curvature improved in 69% of patients treated with thiocolchicine and in 66% of those who received verapamil. Regarding sexual function, there was an increase in the IIEF-5 from 16.69 to 20.85 (p=0.23 in the thiocolchicine group. In the verapamil group the IIEF-5 score dropped from 17.50 to 16.25 (p=0.58. In the thiocolchicine group, the plaque was reduced in 61% of patients. In the verapamil group, 8% presented decreased plaque size. No adverse event was associated to thiocolchicine. Conclusion: The use of thiocolchicine in Peyronie's disease demonstrated improvement on penile curvature and reduction in plaque size. Thiocolchicine presented similar results to verapamil in curvature assessment. No significant side effects were observed with the use of tiocolchicine.

Direct interaction between verapamil and doxorubicin causes the lack of reversal effect of verapamil on P-glycoprotein mediated resistance to doxorubicin in vitro using L1210/VCR cells

International Nuclear Information System (INIS)

Breier, A.; Drobna, Z.; Barancik, M.

1998-01-01

Mouse leukemic cell sub-line L 1210/VCR exerts expressive multidrug resistance (MDR) that is mediated by P-glycoprotein. Cells originally adapted to vincristine are also extremely resistant to doxorubicin. Resistance to both vincristine and doxorubicin is connected with depression of drug uptake. While resistance of L 121 O cells to vincristine could be reversed by verapamil as chemo-sensitizer, resistance of cells to doxorubicin was insensitive to verapamil. Action of verapamil (well-known inhibitor of PGP activity) on multidrug resistance was often used as evidence that MDR is mediated by PGP. From this point it may be possible that the resistance of L1210/VCR cells to vincristine is mediated by PGP and the resistance to doxorubicin is mediated by other PGP-independent system. Another and more probable explanation of different effect of verapamil on resistance of L1210/VCR cells to vincristine and doxorubicin may be deduced from the following fact: Using UV spectroscopy we found that doxorubicin dissolved in water buffered medium interacts effectively with verapamil. This interaction may be responsible for the decrease of concentration of both drugs in free effective form and consequently for higher survival of cells. In contrast to doxorubicin vincristine does not give any interaction with verapamil that is measurable by UV spectroscopy and resistance of L1210/VCR cells to vincristine may be fully reversed by verapamil. (authors)

Verapamil-induced breakdown of the blood-brain barrier presenting as a transient right middle cerebral artery syndrome.

Science.gov (United States)

Pace, Jonathan; Nelson, Jeffrey; Ray, Abhishek; Hu, Yin

2017-12-01

A middle-aged patient presented for elective embolization of an incidentally found right internal carotid aneurysm. An angiogram was performed, during which the left internal carotid artery was visualized to evaluate a second, small aneurysm. During the embolization of the right internal carotid artery aneurysm, a catheter-induced vasospasm was identified that prompted treatment with intra-arterial verapamil. The procedure was uncomplicated; a postoperative rotational flat-panel computed tomography scan was performed on the angiography table that demonstrated right hemisphere contrast staining. The patient developed a right middle cerebral artery (MCA) syndrome after extubation with repeat cerebral angiography negative for occlusion and magnetic resonance imaging negative for stroke. The patient was observed for 48 hours, during which time the patient had slowly improved. At a six-week follow up visit, the patient had fully recovered. We present an interesting case of a verapamil-induced breakdown of the blood-brain barrier and self-limited right MCA syndrome.

INTERACTION OF VERAPAMIL AND LITHIUM AT THE NEUROMUSCULAR JUNCTION ON RAT ISOLATED MUSCLE-HEMIDIAPHRAGM

Directory of Open Access Journals (Sweden)

H. R. Sadeghipour

1998-08-01

Full Text Available It has been reported that cither lithium or verapamil can potentiate the neuromuscular blocking activity of certain neuromuscular blockers. In the present investigation, possible interaction of verapamil with lithium has been described. The dose ■ response effects of verapamil and lithium on diaphragmatic contractility were assessed in vitro. Mechanical responses of the muscle to indirect (nerve and direct (muscle electrical stimulation were recorded. Verapamil depressed rat diaphragm twitch tensions induced by nerve stimulation in a dose - dependent manner with the 50 percent depression of the original twitch tensions (ICSQ by 5.6 xlO^mmol/l."nThe IC50 of verapamil for direct stimulation of the muscle was LI x W'5 mmol II. Partial replacement of sodium chloride by lithium chloride (0.5, 1.5 and 5 mmol /1 in the medium did not change the depressant effect of verapamil on muscle twitches induced by direct (muscle or indirect (nerve electrical stimulation.

Verapamil inhibits tumor progression of chemotherapy-resistant pancreatic cancer side population cells

Science.gov (United States)

ZHAO, LU; ZHAO, YUE; SCHWARZ, BETTINA; MYSLIWIETZ, JOSEF; HARTIG, ROLAND; CAMAJ, PETER; BAO, QI; JAUCH, KARL-WALTER; GUBA, MAKUS; ELLWART, JOACHIM WALTER; NELSON, PETER JON; BRUNS, CHRISTIANE JOSEPHINE

2016-01-01

Tumor side population (SP) cells display stem-like properties that can be modulated by treatment with the calcium channel blocker verapamil. Verapamil can enhance the cytotoxic effects of chemotherapeutic drugs and multi-drug resistance by targeting the transport function of the P-glycoprotein (P-gp). This study focused on the therapeutic potential of verapamil on stem-like SP tumor cells, and further investigated its chemosensitizing effects using L3.6pl and AsPC-1 pancreatic carcinoma models. As compared to parental L3.6pl cells (0.9±0.22%), L3.6pl gemcitabine-resistant cells (L3.6plGres) showed a significantly higher percentage of SP cells (5.38±0.99%) as detected by Hoechst 33342/FACS assays. The L3.6plGres SP cells showed stable gemcitabine resistance, enhanced colony formation ability and increased tumorigenicity. Verapamil effectively inhibited L3.6plGres and AsPC-1 SP cell proliferation in vitro. A pro-apoptotic effect of verapamil was observed in L3.6pl cells, but not in L3.6plGres cells, which was linked to their differential expression of P-gp and equilibrative nucleoside transporter-1 (ENT-1). In an orthotopic pancreatic cancer mouse model, both low and high dose verapamil was shown to substantially reduce L3.6plGres-SP cell tumor growth and metastasis, enhance tumor apoptosis, and reduce microvascular density. PMID:27177126

Prevention of Severe Hypoglycemia-Induced Brain Damage and Cognitive Impairment with Verapamil.

Science.gov (United States)

Jackson, David A; Michael, Trevin; Vieira de Abreu, Adriana; Agrawal, Rahul; Bortolato, Marco; Fisher, Simon J

2018-05-03

People with insulin-treated diabetes are uniquely at risk for severe hypoglycemia-induced brain damage. Since calcium influx may mediate brain damage, we tested the hypothesis that the calcium channel blocker, verapamil, would significantly reduce brain damage and cognitive impairment caused by severe hypoglycemia. Ten-week-old Sprague-Dawley rats were randomly assigned to one of three treatments; 1) control hyperinsulinemic (200 mU.kg -1 min -1 ) euglycemic (80-100mg/dl) clamps (n=14), 2) hyperinsulinemic hypoglycemic (10-15mg/dl) clamps (n=16), or 3) hyperinsulinemic hypoglycemic clamps followed by a single treatment with verapamil (20mg/kg) (n=11). As compared to euglycemic controls, hypoglycemia markedly increased dead/dying neurons in the hippocampus and cortex, by 16-fold and 14-fold, respectively. Verapamil treatment strikingly decreased hypoglycemia-induced hippocampal and cortical damage, by 87% and 94%, respectively. Morris Water Maze probe trial results demonstrated that hypoglycemia induced a retention, but not encoding, memory deficit (noted by both abolished target quadrant preference and reduced target quadrant time). Verapamil treatment significantly rescued spatial memory as noted by restoration of target quadrant preference and target quadrant time. In summary, a one-time treatment with verapamil following severe hypoglycemia prevented neural damage and memory impairment caused by severe hypoglycemia. For people with insulin treated diabetes, verapamil may be a useful drug to prevent hypoglycemia-induced brain damage. © 2018 by the American Diabetes Association.

Impact of concentration and rate of intraluminal drug delivery on absorption and gut wall metabolism of verapamil in humans.

Science.gov (United States)

Glaeser, Hartmut; Drescher, Siegfried; Hofmann, Ute; Heinkele, Georg; Somogyi, Andrew A; Eichelbaum, Michel; Fromm, Martin F

2004-09-01

In humans gut wall metabolism can be quantitatively as important as hepatic drug metabolism in limiting the systemic exposure to drugs after oral administration. However, it has been proposed that the role of gut wall metabolism might be overemphasized, because high luminal drug concentrations would lead to a saturation of gut wall metabolism. Therefore we investigated the impact of concentration and rate of intraluminal drug delivery on absorption (F(abs)) and gastrointestinal extraction (E(GI)) of a luminally administered cytochrome P450 (CYP) 3A4 substrate (verapamil) using a multilumen perfusion catheter in combination with a stable isotope technique. Two 20-cm-long, adjacent jejunal segments were isolated with the multilumen perfusion catheter in 7 subjects. In this study 80 mg of unlabeled verapamil (d0-verapamil 15 min) was infused into one segment over a 15-minute period, 80 mg of 3-fold deuterated verapamil (d3-verapamil 240 min) was administered over a 240-minute period into the other segment, and simultaneously, 5 mg of 7-fold deuterated verapamil (d7-verapamil) was injected intravenously over a 15-minute period. The rate of intraluminal drug delivery had only a modest effect on bioavailability of the verapamil isotopes (after correction for F abs ) (F/F abs d3-verapamil 240 min versus d0-verapamil 15 min, 0.24 +/- 0.10 versus 0.20 +/- 0.09; P d3-verapamil 240 min was 0.50 +/- 0.18 compared with 0.59 +/- 0.14 for d0 -verapamil 15 min ( P d0-verapamil 15 min ) correlated strongly with E GI (d3-verapamil 240 min ) (r = 0.94, P d0-verapamil 15 min /d3-verapamil 240 min (r = 0.62, P =.03). Substantial gut wall metabolism of verapamil occurs in humans and can be predicted from ex vivo data by use of shed enterocytes. The different intraluminal concentrations and rates of intraluminal drug delivery did not lead to a pronounced saturation of intestinal drug metabolism.

Which Target Blood Pressure in Year 2018? Evidence from Recent Clinical Trials.

Science.gov (United States)

Heimark, Sondre; Mariampillai, Julian E; Narkiewicz, Krzysztof; Nilsson, Peter M; Kjeldsen, Sverre E

2018-04-16

The Systolic Blood Pressure Intervention Trial (SPRINT) suggested a favourable effect of lowering blood pressure to Blood Pressure (ACCORD) study, the International Verapamil-Trandolapril Study (INVEST), the Telmisartan, Ramipril or Both in Patients at High Risk for Vascular Events trial (ONTARGET)/the Telmisartan Randomised AssessmenNt Study in aCE iNtolerant participants with cardiovascular Disease (TRANSCEND) study and The Losartan Intervention For Endpoint Reduction in Hypertension (LIFE) study. These studies confirm a positive effect on cardiovascular protection with blood pressure lowering treatment to between 120-140 mmHg in patients with and without diabetes, but no additional effect of lowering blood pressure to blood pressure < 130/80 mmHg appears appropriate in most high-risk hypertensive patients. Additionally, early and sustained BP control below this target is required for optimal cardiovascular protection.

Toxic effects, bioconcentration and depuration of verapamil in the early life stages of common carp (Cyprinus carpio L.)

Energy Technology Data Exchange (ETDEWEB)

Steinbach, Christoph, E-mail: steinbach@frov.jcu.cz [Research Institute of Fish Culture and Hydrobiology, South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, CZ-38925 Vodnany (Czech Republic); Fedorova, Ganna [Research Institute of Fish Culture and Hydrobiology, South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, CZ-38925 Vodnany (Czech Republic); Prokes, Miroslav [Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, v.v.i., Kvetna 8, 603 65 Brno (Czech Republic); Grabicova, Katerina; Machova, Jana; Grabic, Roman; Valentova, Olga; Kroupova, Hana Kocour [Research Institute of Fish Culture and Hydrobiology, South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, CZ-38925 Vodnany (Czech Republic)

2013-09-01

Verapamil is a pharmaceutical that belongs to a group of calcium channel blockers and is mainly used as a treatment of angina pectoris and arterial hypertension. Verapamil has been detected in aquatic environments in concentrations ranging from ng L{sup −1} to μg L{sup −1}. In the present study, a series of acute toxicity tests of verapamil on various developmental stages of common carp (Cyprinus carpio) were conducted. As a result, 96hLC{sub 50} values of verapamil were estimated at 16.4 ± 9.2, 7.3 ± 1.5 and 4.8 ± 0.2 mg L{sup −1} for embryos (E5–E9) and common carp larvae L2 and L5, respectively. Lethal concentrations of verapamil decreased with an increase in the age of the fish. Acute exposure to verapamil significantly reduced the heart rate in the embryos and larvae. In an embryo-larval toxicity test (sub-chronic exposure), the bioconcentration, depuration, and toxic effects of verapamil were assessed in common carp. The fish were exposed to verapamil in a concentration of 0.463 (environmentally relevant), 4.63, 46.3 and 463 μg L{sup −1}. Verapamil had no effect on the accumulated mortality, hatching, condition factor, growth or ontogeny of the fish in any of the tested concentrations. In carp exposed to 463 and 46.3 μg L{sup −1} of verapamil, significantly higher occurrences of malformations and edemas were observed compared to the control. The bioconcentration factor of verapamil in whole fish homogenates ranged between 6.6 and 16.6 and was therefore below the critical value for hazard substances (BCF > 500). The half-life and the 95% depuration time for the tested compound were estimated to be 10.2 ± 1.6 days and 44.2 ± 8.6 days, respectively. No effects of verapamil on the studied endpoints were observed at environmentally relevant concentrations. - Highlights: • Study of the acute and sub-chronic toxicity of verapamil on early-life stages of common carp. • Acute exposure to verapamil reduced the heart rate in early-life stages of

Toxic effects, bioconcentration and depuration of verapamil in the early life stages of common carp (Cyprinus carpio L.)

International Nuclear Information System (INIS)

Steinbach, Christoph; Fedorova, Ganna; Prokes, Miroslav; Grabicova, Katerina; Machova, Jana; Grabic, Roman; Valentova, Olga; Kroupova, Hana Kocour

2013-01-01

Verapamil is a pharmaceutical that belongs to a group of calcium channel blockers and is mainly used as a treatment of angina pectoris and arterial hypertension. Verapamil has been detected in aquatic environments in concentrations ranging from ng L −1 to μg L −1 . In the present study, a series of acute toxicity tests of verapamil on various developmental stages of common carp (Cyprinus carpio) were conducted. As a result, 96hLC 50 values of verapamil were estimated at 16.4 ± 9.2, 7.3 ± 1.5 and 4.8 ± 0.2 mg L −1 for embryos (E5–E9) and common carp larvae L2 and L5, respectively. Lethal concentrations of verapamil decreased with an increase in the age of the fish. Acute exposure to verapamil significantly reduced the heart rate in the embryos and larvae. In an embryo-larval toxicity test (sub-chronic exposure), the bioconcentration, depuration, and toxic effects of verapamil were assessed in common carp. The fish were exposed to verapamil in a concentration of 0.463 (environmentally relevant), 4.63, 46.3 and 463 μg L −1 . Verapamil had no effect on the accumulated mortality, hatching, condition factor, growth or ontogeny of the fish in any of the tested concentrations. In carp exposed to 463 and 46.3 μg L −1 of verapamil, significantly higher occurrences of malformations and edemas were observed compared to the control. The bioconcentration factor of verapamil in whole fish homogenates ranged between 6.6 and 16.6 and was therefore below the critical value for hazard substances (BCF > 500). The half-life and the 95% depuration time for the tested compound were estimated to be 10.2 ± 1.6 days and 44.2 ± 8.6 days, respectively. No effects of verapamil on the studied endpoints were observed at environmentally relevant concentrations. - Highlights: • Study of the acute and sub-chronic toxicity of verapamil on early-life stages of common carp. • Acute exposure to verapamil reduced the heart rate in early-life stages of common carp. • The

Successful usage of intravenous lipid emulsion in treatment of acute verapamil poisoning: A case report

Directory of Open Access Journals (Sweden)

Vuković-Ercegović Gordana

2017-01-01

Full Text Available Introduction. During the last few years, intravenous lipid emulsions have been effectively used in treatment of acute poisonings with lipophilic substances, including verapamil. Case report. A 37-year-old women presented 1 hour after ingestion of 2.8 g verapamil with hypotension and complete heart block. Because of the applied standard therapy failure and further patients impairment, Intralipid® 20% was used. Sinus rhythm was restored, arterial blood pressure increased and verapamile concentrations, both total and free decreased. Conclusion. Intravenous lipid emulsion can be important in treatment of severe acute intoxication and cardiotoxicity caused by verapamil.

Requirements for drug monitoring of verapamil: experience from an unselected group of patients with cardiovascular disease

DEFF Research Database (Denmark)

Husum, D; Johnsen, A; Jensen, Gorm Boje

1990-01-01

variation (variation coefficient 35.8, 1.9, and 7.4, at the dosage levels 120, 240 and 340 mg per day). No significant correlation was found between serum verapamil levels age, sex, or weight. No significant effect of digoxin on the concentration of serum verapamil was found. No relation was observed...... 620 and D 617 indicated saturation of the first-pass metabolism. In conclusion, therapeutic drug monitoring is not indicated during routine verapamil treatment, whereas single measurements of verapamil may be warranted in patients not responding to treatment in order to identify fast metabolizers...

Efficacy of verapamil as an adjunctive treatment in children with drug-resistant epilepsy

DEFF Research Database (Denmark)

Nicita, Francesco; Spalice, Alberto; Papetti, Laura

2014-01-01

Verapamil, a voltage-gated calcium channel blocker, has been occasionally reported to have some effect on reducing seizure frequency in drug-resistant epilepsy or status epilepticus. We aimed to investigate the efficacy of verapamil as add-on treatment in children with drug-resistant epilepsy....

Microneedle-assisted delivery of verapamil hydrochloride and amlodipine besylate.

Science.gov (United States)

Kaur, Monika; Ita, Kevin B; Popova, Inna E; Parikh, Sanjai J; Bair, Daniel A

2014-02-01

The aim of this project was to study the effect of stainless steel solid microneedles and microneedle rollers on percutaneous penetration of verapamil hydrochloride and amlodipine besylate. Verapamil, 2-(3,4-dimethooxyphenyl)-5-[2-(3,4 dimethoxyphenyl)ethyl-methyl-amino]-2-propan-2-yl-pentanenitrile is a calcium channel blocker agent that regulates high blood pressure by decreasing myocardial contractilty, heart rate and impulse conduction. Amlodipine, (R, S)-2-[(2-aminoethoxy) methyl]-4-(2-chlorophenyl)-3-ethoxycarbonyl-5-methoxycarbonyl-6-methyl-1, 4-dihydropyridine, is a calcium channel blocker that is used for the management of hypertension and ischemic heart disease. Passive penetration of verapamil and amlodipine across the skin is low. In vitro studies were performed with microneedle-treated porcine ear skin using vertical static Franz diffusion cells (PermeGear, Hellertown, PA, USA). The receiver chamber contained 5ml of PBS (pH7.4) and was constantly maintained at 37°C temperature with a water circulation jacket. The diffusion area of the skin was 1.77cm(2). The donor compartment was loaded with 1ml of the solution containing 2.5mg/ml of amlodipine besylate. The donor chamber was covered with parafilm to avoid evaporation. Passive diffusion across untreated porcine skin served as control. Aliquots were taken every 2h for 12h and analyzed by liquid chromatography-mass spectrometry. Transcutaneous flux of verapamil increased significantly from 8.75μg/cm(2)/h to 49.96μg/cm(2)/h across microneedle-roller treated porcine skin. Percutaneous flux of amlodipine besylate following the use of stainless steel microneedles was 22.39μg/cm(2)/h. Passive flux for the drug was 1.57μg/cm(2)/h. This enhancement of amlodipine flux was statistically significant. Transdermal flux of amlodipine with microneedle roller was 1.05μg/cm(2)/h in comparison with passive diffusion flux of 0.19μg/cm(2)/h. The difference in flux values was also statistically significant. Stainless

Sustained release of verapamil hydrochloride from sodium alginate microcapsules.

Science.gov (United States)

Farhana, S Ayesha; Shantakumar, S M; Shyale, Somashekar; Shalam, Md; Narasu, Laxmi

2010-04-01

The objective of the present study was to develop sustained release microcapsules of verapamil hydrochloride (VH) using biodegradable polymers. For this purpose microcapsules embedded verapamil hydrochloride were prepared using sodium alginate alone and also by incorporating some co polymers like methyl cellulose (MC), sodium carboxy methyl cellulose (SCMC) , poly vinyl pyrollidone (PVP) and xanthan gum by employing complex emulsion method of microencapsulation. Microcapsules were prepared in various core: coat ratios to know the effect of polymer and co polymers on drug release. Overall ten formulations were prepared and evaluated for flow behaviour, sieve analysis, drug entrapment efficiency, in vitro dissolution studies, stability studies, including scanning electron microscopy and DSC. The resulting microcapsules were discrete, large, spherical and also free flowing. The drug content in all the batches of microcapsules was found to be uniform. The release was depended on core: coat ratio and nature of the polymers. FTIR analysis revealed chemical integrity between Verapamil hydrochloride (VH), sodium alginate and between the copolymers. Among the four copolymers used methyl cellulose retarded the drug release more than the other three, hence the same formulation was subjected for in vivo studies. The drug release from the microcapsules was found to be following non fickian diffusion. Mechanism of drug release was diffusion controlled first order kinetics. Drug diffusion co efficient and correlation co efficient were also assessed by using various mathematical models. In vivo result analysis of pharmacokinetic parameters revealed that t max of reference and test formulations were almost same. From the study it was concluded that, sustained release Verapamil hydro chloride microcapsules could be achieved with success using sodium alginate alone and also in combination with other biodegradable polymers.

INTRALESIONAL VERAPAMIL INJECTION IN TREATMENT OF

African Journals Online (AJOL)

Patients and Methods Twenty-six patients with Peyronie's disease were divided into two groups: the verapamil treatment group. (study group) including 13 patients and the saline group (control group) including an- other 13 patients. The patients' age ranged from 35 to 58 years with a mean age of. 43.75 years. The patients ...

Comparative effect and safety of verapamil in keloid and hypertrophic scar treatment: a meta-analysis

Directory of Open Access Journals (Sweden)

Li ZN

2016-11-01

Full Text Available Zhouna Li, Zhehu Jin Department of Dermatology, Yanbian University Affiliated hospital, Yanji, Jilin, People’s Republic of China Background: Keloids and hypertrophic scars are the most common types of pathological scarring. Traditionally, keloids have been considered as a result of aberrant wound healing, involving excessive fibroblast participation that is characterized by hyalinized collagen bundles. However, the usefulness of this characterization has been questioned. In recent years, studies have reported the appropriate use of verapamil for keloids and hypertrophic scars.Methods: Searches were conducted on the databases Medline, Embase, Cochrane, PubMed, and China National Knowledge Infrastructure from 2006 to July 2016. State12.0 was used for literature review, data extraction, and meta-analysis. Treatment groups were divided into verapamil and nonverapamil group. Nonverapamil group includes steroids and intense pulsed light (IPL therapy. Total effective rates include cure rate and effective rate. Cure: skin lesions were completely flattened, became soft and symptoms disappeared. Efficacy: skin lesions subsided, patient significantly reduced symptoms. Inefficient definition of skin was progression free or became worse. Random-effects model was used for the meta-analysis.Results: Six studies that included 331 patients with keloids and hypertrophic scars were analyzed. Analysis of the total effective rate of skin healing was performed. The total effective rates in the two groups were 54.07% (verapamil and 53.18% (nonverapamil, respectively. The meta-analysis showed that there was no difference between the two groups. We also compared the adverse reactions between the verapamil treatment group and the steroids treatment group in two studies, and the result indicated that the verapamil group showed less adverse reactions.Conclusion: There were no differences between the application of verapamil and nonverapamil group in keloids and

Effect of verapamil on cellular uptake of Tc-99m MIBI and tetrofosmin on several cancer cells

International Nuclear Information System (INIS)

Kim, Dae Hyun; Yoo, Jung Ah; Bae, Jin Ho; Jeong, Shin Young; Suh, Myung Rang; Ahn, Byeong Cheol; Lee, Kyu Bo; Lee, Jae Tae

2004-01-01

Cellular uptake of 99 mTc-sestamibi (MIBI) and 99 mTc-tetrofosmin (TF) is low in cancer cells expressing multidrug resistance(MDR) by p-glycoprotein(Pgp) or multidrug related protein(MRP). Verapamil is known to increase cellular uptake of MIBI in MDR cancer cells, but is recently reported to have different effects on tracer uptake in certain cancer cells. This study was prepared to evaluate effects of verapamil on cellular uptake of MIBI and TF in several cancer cells. Cellular uptakes of Tc-99m MIBI and TF were measured in erythroleukemia K562 cell, breast cancer MCF7 cell, and human ovarian cancer SK-OV-3 cells, and data were compared with those of doxorubicin-resistant K562(Ad) cells. RT-PCR and Western blot analysis were used for the detection of mdr1 mRNA and Pgp expression, and to observe changes in isotypes of PKC enzyme. Effects of verapamil on MIBI and TF uptake were evaluated at different concentrations upto 200 μM at 1*10 6 cells/ m l at 37.deg.C. Radioactivity in supernatant and pellet was measured with gamma counter to calculate cellular uptake ratio. Toxicity of verapamil was measured with MTT assay. Cellular uptakes of MIBI and TF were increased by time in four cancer cells studied. Co-incubation with verapamil resulted in an increase in uptake of MIBI and TF in K562(Adr) cell at a concentration of 100 μM and the maximal increase at 50 μM was 10-times to baseline. In contrast, uptakes of MIBI and TF in K562, MCF7m SK-OV3 cells were decreased with verapamil treatment at a concentration over 1 μM. With a concentration of 200 μM verapamil, respectively. Cellular uptakes of MIBI and TF in MCF7 and SK-OV-3 cells were not changed with 10μM, but were also decreased with verapamil higher than 10μM, resulting 40% and 5% of baseline at 50 μM. MTT assay of four cells revealed that K562, MCF7, SK-OV3 were not damaged with verapamil at 200 μM. Although verapamil increases uptake of MIBI and TF in MDR cancer cells, cellular uptakes were further decreased

Effect of verapamil on bronchial goblet cells of asthma: an experimental study on sensitized animals.

Science.gov (United States)

Khakzad, Mohammad Reza; Mirsadraee, Majid; Mohammadpour, Amirhooshang; Ghafarzadegan, Kamram; Hadi, Raziye; Saghari, Mahdiye; Meshkat, Mojtaba

2012-04-01

Goblet cell hyperplasia (GCH) and mucus hypersecretion in the airway is recognized as an important contributor to morbidity and mortality in asthma and COPD. Verapamil is a calcium channel blocker that binds to the alpha-subunit of L-type calcium channels and inhibits the mucin gene via the calmodulin and CaM kinase pathway. The objective of this study was to determine the in vivo effect of verapamil on GCH and eosinophilic inflammation in sensitized mice. Male BALB/c mice were sensitized to ovalbumin using the standard method. Two groups of animals were received verapamil via an intramuscular injection: 1-low dose (0.5 mg/kg/day for two weeks), 2-high dose (1.5 mg/kg/day for two weeks). Serum and bronchoalveolar lavage fluid (BALF) was collected and analyzed for inflammatory cells, interferon-γ and IL-4. The left lung was sent for histopathological evaluation, especially for periodic acid-Schiff (PAS), to identify goblet cells in the epithelium. The degree of inflammatory cell infiltration, including eosinophils, mucus plugging, and smooth muscle thickness of the airways were classified on a semi quantitative scale. Inflammatory cell infiltration in peribronchial and perivascular areas was observed in all sensitized groups. Eosinophils percentage in the BALF significantly decreased in verapamil-treated mice compared with sensitized mice (from 19.8% in asthmatic to 5.4% for low dose and 4.4% for high dose). The ratio of airway goblet cells per epithelial cells were significantly lower in verapamil-treated mice versus sensitized mice (1.57±1.30% for low dose; 1.50±0.93% for high dose versus 12.93±7.55%, Pcells decreased significantly in verapamil-treated mice versus sensitized mice (mean score was 1.45±0.30 for low dose; 0.81±1.00 for high dose versus 2.85±0.86 in the sensitized control group, P<0.05, respectively). The concentration of serum and BALF-IFN-γ in verapamil-treated mice markedly increased by the verapamil treatment when compared to sensitized

Comparative effect and safety of verapamil in keloid and hypertrophic scar treatment: a meta-analysis.

Science.gov (United States)

Li, Zhouna; Jin, Zhehu

2016-01-01

Keloids and hypertrophic scars are the most common types of pathological scarring. Traditionally, keloids have been considered as a result of aberrant wound healing, involving excessive fibroblast participation that is characterized by hyalinized collagen bundles. However, the usefulness of this characterization has been questioned. In recent years, studies have reported the appropriate use of verapamil for keloids and hypertrophic scars. Searches were conducted on the databases Medline, Embase, Cochrane, PubMed, and China National Knowledge Infrastructure from 2006 to July 2016. State12.0 was used for literature review, data extraction, and meta-analysis. Treatment groups were divided into verapamil and nonverapamil group. Nonverapamil group includes steroids and intense pulsed light (IPL) therapy. Total effective rates include cure rate and effective rate. Cure: skin lesions were completely flattened, became soft and symptoms disappeared. Efficacy: skin lesions subsided, patient significantly reduced symptoms. Inefficient definition of skin was progression free or became worse. Random-effects model was used for the meta-analysis. Six studies that included 331 patients with keloids and hypertrophic scars were analyzed. Analysis of the total effective rate of skin healing was performed. The total effective rates in the two groups were 54.07% (verapamil) and 53.18% (nonverapamil), respectively. The meta-analysis showed that there was no difference between the two groups. We also compared the adverse reactions between the verapamil treatment group and the steroids treatment group in two studies, and the result indicated that the verapamil group showed less adverse reactions. There were no differences between the application of verapamil and nonverapamil group in keloids and hypertrophic scars treatment. Verapamil could act as an effective alternative modality in the prevention and treatment of keloid and hypertrophic scars. A larger number of studies are required to

Circadian variation in the pharmacokinetics of verapamil

DEFF Research Database (Denmark)

Jespersen, C M; Frederiksen, M; Hansen, J F

1989-01-01

greater bioavailability (AUC) and a prolonged time to peak concentration was found. During the night (24.00 h-06.00 h) the half-life of verapamil was significantly longer than during the day (16.00 h-22.00 h). These differences in pharmacokinetics may be due to reduced hepatic blood flow at night...

The acute hemodynamic effects of intravenous verapamil in coronary artery disease. Assessment by equilibrium-gated radionuclide ventriculography

International Nuclear Information System (INIS)

Klein, H.O.; Ninio, R.; Oren, V.; Lang, R.; Sareli, P.; DiSegni, E.; David, D.; Guerrero, J.; Kaplinsky, E.

1983-01-01

The acute hemodynamic effects of an i.v. bolus of verapamil, 0.1 mg/kg or 0.06-0.075 mg/kg, were examined by serial radionuclide studies in 46 patients with coronary artery disease. In 20 patients with ejection fractions (EFs) greater than 35% (group 1A), verapamil, 0.1 mg/kg given over 1-11/2 minutes, had a biphasic effect: first, a transient decrease in EF accompanied by increased left ventricular (LV) volumes and cardiac output equivalents; then, an overshoot of EF to values above control, accompanied by a decrease in peripheral vascular resistance and a drastic decrease in LV volumes, while cardiac output equivalent remained slightly elevated. In eight patients with EFs less than 35% (group 1B), only the first effect on EF was noted. In 10 patients with EFs greater than 35% (group 2), verapamil, 0.06-0.075 mg/kg, exerted qualitatively similar but milder effects on hemodynamic function. Finally, verapamil, 0.1 mg/kg given more slowly, over 2-21/2 minutes, produced no significant changes in EF or LV volumes in another eight patients (group 3). The acute effects of verapamil are thus both time-related and dose-dependent. They are also related to the baseline functional reserve of the left ventricle. This study documents that verapamil exerts a depressant effect on LV function. However, the transient nature of this depression and the quick recovery to normal or above-normal values indicate that verapamil, in the doses used in this study, is safe to use intravenously in patients with coronary artery disease

Less adrenergic response to mental task during verapamil compared to amlodipine treatment in hypertensive subjects

NARCIS (Netherlands)

Sevre, K; Lefrandt, JD; Eide, [No Value; Smit, AJ; Rostrup, M

2001-01-01

We compared the effects of amlodipine and verapamil slow release on autonomic responses to a 5-min mental arithmetic test (MST) in patients with mild to moderate hypertension. Twenty subjects received 8 weeks of verapamil slow release 240 mg or amlodipine 10 mg in a double-blind crossover design,

Activity of moxifloxacin and linezolid against Mycobacterium tuberculosis in combination with potentiator drugs verapamil, timcodar, colistin and SQ109.

Science.gov (United States)

de Knegt, Gerjo J; van der Meijden, Aart; de Vogel, Corné P; Aarnoutse, Rob E; de Steenwinkel, Jurriaan E M

2017-03-01

Current treatment for tuberculosis (TB) is complicated by the emergence of multidrug resistant TB (MDR-TB). As a result, there is an urgent need for new powerful anti-TB regimens and novel strategies. In this study, we aimed to potentiate a moxifloxacin + linezolid backbone as treatment for MDR-TB with the efflux pump inhibitors verapamil and timcodar as well as with drugs that act on mycobacterial cell wall stability such as colistin and SQ109. Using a time-kill kinetics assay, the activities of moxifloxacin, linezolid, verapamil, timcodar, colistin and SQ109 as single drugs against Mycobacterium tuberculosis were evaluated. In addition, the activity of the moxifloxacin + linezolid backbone in combination with one of the potentiator drugs was assessed. As little as 0.125 mg/L moxifloxacin achieved 99% killing of M. tuberculosis after 6 days of exposure. Linezolid showed moderate killing but 99% killing was not achieved. Verapamil, timcodar and colistin only resulted in killing with the highest concentrations tested but 99% killing was not achieved. SQ109 resulted in complete elimination after 1 day of exposure to 256 mg/L and in 99% elimination after 6 days of exposure to 1 mg/L. Furthermore, colistin added to the moxifloxacin + linezolid backbone resulted in increased elimination, whereas verapamil, timcodar and SQ109 showed no added value to the backbone. This finding that colistin potentiates the activity of the moxifloxacin + linezolid backbone against M. tuberculosis suggests its potential role in further studies on the applicability of a moxifloxacin + linezolid treatment of MDR-TB. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Verapamil reverses PTH- or CRF-induced abnormal fatty acid oxidation in muscle

International Nuclear Information System (INIS)

Perna, A.F.; Smogorzewski, M.; Massry, S.G.

1988-01-01

Chronic renal failure (CRF) is associated with impaired long chain fatty acids (LCFA) oxidation by skeletal muscle mitochondria. This is due to reduced activity of carnitine palmitoyl transferase (CPT). These derangements were attributed to the secondary hyperparathyroidism of CRF, since prior parathyroidectomy in CRF rats reversed these abnormalities and PTH administration to normal rats reproduced them. It was proposed that these effects of PTH are mediated by its ionophoric property leading to increased entry of calcium into skeletal muscle. A calcium channel blocker may, therefore, correct these derangements. The present study examined the effects of verapamil on LCFA oxidation, CPT activity by skeletal muscle mitochondria, and 45 Ca uptake by skeletal muscle obtained from CRF rats and normal animals treated with PTH with and without verapamil. Both four days of PTH administration and 21 days of CRF produced significant (P less than 0.01) reduction in LCFA oxidation and CPT activity of skeletal muscle mitochondria, and significant (P less than 0.01) increment in 45 Ca uptake by skeletal muscle. Simultaneous treatment with verapamil corrected all these derangements. Administration of verapamil alone to normal rats did not cause a significant change in any of these parameters. The data are consistent with the proposition that the alterations in LCFA in CRF or after PTH treatment are related to the ionophoric action of the hormone and could be reversed by a calcium channel blocker

Development and evaluation of floating microspheres of verapamil hydrochloride Desenvolvimento e avaliação de microesferas flutuantes de cloridrato de verapamil

Directory of Open Access Journals (Sweden)

Yuveraj Singh Tanwar

2007-12-01

Full Text Available The present study involves preparation and evaluation of floating microspheres of verapamil hydrochloride for improving the drug bioavailability by prolongation of gastric residence time. Cellulose acetate, acrycoat S100 and eudragit S100 microspheres loaded with verapamil hydrochloride were prepared by solvent diffusion-evaporation method. The microspheres had smooth surfaces, with free-flowing and good-packing properties. The yield of the microspheres was up to 70.51% and cellulose acetate microspheres entrapped the maximum amount of the drug. Scanning electron microscopy confirmed their hollow structures with sizes in the range 251.80 to 350.75 mm. The prepared microspheres exhibited prolonged drug release and remained buoyant for more than 12 h. Radiographic images of dog stomach revealed that cellulose acetate microspheres loaded with barium sulphate floated on the gastric fluid for about 3.2 h. In vitro release studies demonstrated non-Fickian diffusion of drug from the microspheres.O presente estudo envolve a preparação e a avaliação de microesferas flutuantes de cloridrato de verapamil para o melhoramento da biodisponibilidade do fármaco por meio do prolongamento do tempo de residência gástrica. Prepararam-se, por meio do método de difusão-evaporação de solvente, microesferas de acetato de celulose, acrycoat S100 e eudragit S100 carregadas com cloridrato de verapamil. As microesferas apresentaram superfícies regulares, com propriedades de fluxo livre e de bom empacotamento. O rendimento das microesferas foi superior a 70,51% e as microesferas de acetato de celulose captaram a quantidade máxima do fármaco. Microscopia eletrônica de varredura confirmou as cavidades em suas estruturas, com tamanhos na faixa de 251,80 a 350,75 mm. As microesferas preparadas apresentaram liberação prolongada do fármaco e permaneceram flutuantes por mais que 12 h. Imagens radiográficas do estômago de cão revelaram que as esferas de acetato

Enhancement of absorption and bioavailability of echinacoside by verapamil or clove oil

Directory of Open Access Journals (Sweden)

Shen JY

2015-08-01

Full Text Available Jin-Yang Shen,1,* Xiao-Lin Yang,2,* Zhong-Lin Yang,1 Jun-Ping Kou,1 Fei Li11State Key Laboratory of Natural Medicines, China Pharmaceutical University, 2Key Laboratory of Pharmaceutical and Biological Marine Resources Research and Development of Jiangsu Province, Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China*These authors contributed equally to this workPurpose: This present study investigated the absorption kinetics of echinacoside (ECH in situ and in vitro and its oral bioavailability in rats. Additional aim was to find an agent(s to promote ECH absorption and oral bioavailability among two efflux proteins and three absorption promoters.Methods: ECH absorption behaviors were investigated by everted gut sac model in vitro and single-pass intestinal perfusion model in situ. Pharmacokinetics study was performed to investigate the influences of verapamil and clove oil on ECH bioavailability in vivo. All samples were measured at different time intervals by high performance liquid chromatography.Results: The results showed that the effective permeability coefficient (Peff and apparent permeability coefficient of ECH were 0.83×10-6–3.23×10-6 cm/s and 2.99×10-6–9.86×10-6 cm/s, respectively. The Peff among duodenum, jejunum, and ileum were not statistically different, but they were higher than colon (P<0.01, which demonstrated that intestinal ECH absorption was poor and site dependent. Additionally, verapamil and clove oil significantly increased the jejunal Peff of ECH both in situ and in vitro. Moreover, the bioavailability of ECH in combination with verapamil and clove oil were increased by 1.37-fold (P<0.05 and 2.36-fold (P<0.001, respectively, when compared to ECH group. Overall, verapamil and clove oil facilitated ECH absorption and oral bioavailability.Conclusion: The absorption and bioavailability of ECH were enhanced by verapamil and clove oil, respectively, both in vitro and in vivo. Consequently

K+ channel openers restore verapamil-inhibited lung fluid resolution and transepithelial ion transport

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Su Xue-Feng

2010-05-01

Full Text Available Abstract Background Lung epithelial Na+ channels (ENaC are regulated by cell Ca2+ signal, which may contribute to calcium antagonist-induced noncardiogenic lung edema. Although K+ channel modulators regulate ENaC activity in normal lungs, the therapeutical relevance and the underlying mechanisms have not been completely explored. We hypothesized that K+ channel openers may restore calcium channel blocker-inhibited alveolar fluid clearance (AFC by up-regulating both apical and basolateral ion transport. Methods Verapamil-induced depression of heterologously expressed human αβγ ENaC in Xenopus oocytes, apical and basolateral ion transport in monolayers of human lung epithelial cells (H441, and in vivo alveolar fluid clearance were measured, respectively, using the two-electrode voltage clamp, Ussing chamber, and BSA protein assays. Ca2+ signal in H441 cells was analyzed using Fluo 4AM. Results The rate of in vivo AFC was reduced significantly (40.6 ± 6.3% of control, P Ca3.1 (1-EBIO and KATP (minoxidil channel openers significantly recovered AFC. In addition to short-circuit current (Isc in intact H441 monolayers, both apical and basolateral Isc levels were reduced by verapamil in permeabilized monolayers. Moreover, verapamil significantly altered Ca2+ signal evoked by ionomycin in H441 cells. Depletion of cytosolic Ca2+ in αβγ ENaC-expressing oocytes completely abolished verapamil-induced inhibition. Intriguingly, KV (pyrithione-Na, K Ca3.1 (1-EBIO, and KATP (minoxidil channel openers almost completely restored the verapamil-induced decrease in Isc levels by diversely up-regulating apical and basolateral Na+ and K+ transport pathways. Conclusions Our observations demonstrate that K+ channel openers are capable of rescuing reduced vectorial Na+ transport across lung epithelial cells with impaired Ca2+ signal.

Rapid solid-phase extraction method to quantify [11C]-verapamil, and its [11C]-metabolites, in human and macaque plasma

International Nuclear Information System (INIS)

Unadkat, Jashvant D.; Chung, Francisco; Sasongko, Lucy; Whittington, Dale; Eyal, Sara; Mankoff, David; Collier, Ann C.; Muzi, Mark; Link, Jeanne

2008-01-01

Introduction: P-glycoprotein (P-gp), an efflux transporter, is a significant barrier to drug entry into the brain and the fetus. The positron emission tomography (PET) ligand, [ 11 C]-verapamil, has been used to measure in vivo P-gp activity at various tissue-blood barriers of humans and animals. Since verapamil is extensively metabolized in vivo, it is important to quantify the extent of verapamil metabolism in order to interpret such P-gp activity. Therefore, we developed a rapid solid-phase extraction (SPE) method to separate, and then quantify, verapamil and its radiolabeled metabolites in plasma. Methods: Using high-performance liquid chromatography (HPLC), we established that the major identifiable circulating radioactive metabolite of [ 11 C]-verapamil in plasma of humans and the nonhuman primate, Macaca nemestrina, was [ 11 C]-D-617/717. Using sequential and differential pH elution on C 8 SPE cartridges, we developed a rapid method to separate [ 11 C]-verapamil and [ 11 C]-D-617/717. Recovery was measured by spiking the samples with the corresponding nonradioactive compounds and assaying these compounds by HPLC. Results: Verapamil and D-617/717 recovery with the SPE method was >85%. When the method was applied to PET studies in humans and nonhuman primates, significant plasma concentration of D-617/717 and unknown polar metabolite(s) were observed. The SPE and the HPLC methods were not significantly different in the quantification of verapamil and D-617/717. Conclusions: The SPE method simultaneously processes multiple samples in less than 5 min. Given the short half-life of [ 11 C], this method provides a valuable tool to rapidly determine the concentration of [ 11 C]-verapamil and its [ 11 C]-metabolites in human and nonhuman primate plasma

Addition of verapamil in the treatment of severe myoclonic epilepsy in infancy.

Science.gov (United States)

Iannetti, Paola; Parisi, Pasquale; Spalice, Alberto; Ruggieri, Martino; Zara, Federico

2009-07-01

We report on the use of the voltage-gated calcium channel blocker (Vg-CCB), verapamil, as an add-on anticonvulsant medication in two girls, 4 and 14 years of age, who were affected by severe myoclonic epilepsy in infancy (SMEI) or Dravet syndrome, a channelopathy caused by abnormalities in the voltage-gated sodium channel neuronal type alpha1 subunit (SCN1A) gene at 2q24. Both girls had pharmacoresistant epilepsy and developmental delay. Mutation analysis for the SCN1A gene revealed a missense mutation in exon 2 in the 4-year-old girl. Verapamil was co-administered in both children with a prompt response in controlling status epilepticus, myoclonic jerks, and partial and generalized seizures. The therapeutic effect lasted 13 months in the 14-year-old girl, while it is still present after a 20-month follow-up period in the 4-year-old girl who, in addition, has experienced improvement in motor and language development. The verapamil vVg-CCB, which crosses the blood-brain barrier (BBB): (a) inhibits the P-glycoprotein, an active efflux transporter protein expressed in normal tissue, including the brain, which is believed to contribute to the in situ phenomenon of multidrug resistance; and (b) may regulate membrane depolarization induced by abnormal sodium channels functions by modulating the abnormal Ca++ influxes into neurons with subsequent cell resting. This is the first report on long-lasting verapamil therapy in SMEI. The functional consequences of such in vivo modulating effects on Ca++ channels could contribute to rational targeting for future molecular therapeutic approaches in pharmacoresistant epileptic channelopathies.

Effects of verapamil on left ventricular systolic and diastolic function in patients with hypertrophic cardiomyopathy: pressure-volume analysis with a nonimaging scintillation probe.

Science.gov (United States)

Bonow, R O; Ostrow, H G; Rosing, D R; Cannon, R O; Lipson, L C; Maron, B J; Kent, K M; Bacharach, S L; Green, M V

1983-11-01

To investigate the effects of verapamil on left ventricular systolic and diastolic function in patients with hypertrophic cardiomyopathy, we studied 14 patients at catheterization with a nonimaging scintillation probe before and after serial intravenous infusions of low-, medium-, and high-dose verapamil (total dose 0.17 to 0.72 mg/kg). Percent change in radionuclide stroke counts after verapamil correlated well with percent change in thermodilution stroke volume (r = .87), and changes in diastolic and systolic counts were used to assess relative changes in left ventricular volumes after verapamil. Verapamil produced dose-related increases in end-diastolic counts (19 +/- 9% increase; p less than .001), end-systolic counts (91 +/- 54% increase; p less than .001), and stroke counts (7 +/- 10% increase; p less than .02). This was associated with a decrease in ejection fraction (83 +/- 8% control, 73 +/- 10% verapamil; p less than .001) and, in the 10 patients with left ventricular outflow tract gradients, a reduction in gradient (62 +/- 27 mm Hg control, 32 +/- 35 mm Hg verapamil; p less than .01). The end-systolic pressure-volume relation was shifted downward and rightward in all patients, suggesting a negative inotropic effect. In 10 patients, left ventricular pressure-volume loops were constructed with simultaneous micromanometer pressure recordings and the radionuclide time-activity curve. In five patients, verapamil shifted the diastolic pressure-volume curve downward and rightward, demonstrating improved pressure-volume relations despite the negative inotropic effect, and also increased the peak rate of rapid diastolic filling. In the other five patients, the diastolic pressure-volume relation was unaltered by verapamil, and increased end-diastolic volumes occurred at higher end-diastolic pressures; in these patients, the peak rate of left ventricular diastolic filling was not changed by verapamil. The negative inotropic effects of intravenous verapamil are

Synthesis and preclinical evaluation of [11C]D617, a metabolite of (R)-[11C]verapamil

NARCIS (Netherlands)

Verbeek, Joost; Syvänen, Stina; Schuit, Robert C.; Eriksson, Jonas; de Lange, Elizabeth C M; Windhorst, Albert D.; Luurtsema, Gert; Lammertsma, Adriaan A.

2012-01-01

OBJECTIVES: (R)-[(11)C]verapamil is widely used as a positron emission tomography (PET) tracer to evaluate P-glycoprotein (P-gp) functionality at the blood-brain barrier in man. A disadvantage of (R)-[(11)C]verapamil is the fact that its main metabolite, [(11)C]D617, also enters the brain. For

Fast dissolving strips: A novel approach for the delivery of verapamil

Directory of Open Access Journals (Sweden)

S Kunte

2010-01-01

Full Text Available Objective: Fast dissolving drug delivery system offers a solution for those patients having difficulty in swallowing tablets/capsules etc. Verapamil is a calcium channel blocker used as an antianginal, antiarrhythmic, and antihypertensive agent with extensive first pass metabolism which results in less bioavailability. This work investigated the possibility of developing verapamil fast dissolving strips allowing fast, reproducible drug dissolution in the oral cavity; thus bypassing first pass metabolism. Materials and methods: The fast dissolving strips were prepared by solvent casting technique with the help of HPMC E6 and maltodextrin. The strips were evaluated for drug content uniformity, film thickness, folding endurance, in vitro disintegration time, in vitro dissolution studies, surface pH study, and palatability study. Results: Official criteria for evaluation parameters were fulfilled by all formulations. Disintegration time showed by formulations was found to be in range of 20.4-28.6 sec. Based on the evaluation parameters, the formulation containing 2% HPMC E6 and 3.5% maltodextrin showed optimum performance against other formulations. Conclusion: It was concluded that the fast dissolving strips of verapamil can be made by solvent casting technique with enhanced dissolution rate, taste masking, and hence better patient compliance and effective therapy

Postabsorption concentration peaks with brand-name and generic verapamil: a double-blind, crossover study in elderly hypertensive patients.

Science.gov (United States)

Saseen, J J; Porter, J A; Barnette, D J; Bauman, J L; Zajac, E J; Carter, B L

1997-06-01

The pharmacokinetic actions, bioequivalence, and cardiovascular effects of two verapamil products were studied in a randomized, double-blind, crossover study in eight elderly hypertensive patients (median age, 69.5 years; range, 60-79 years) given brand-name or generic immediate-release verapamil in 120-mg twice-daily doses for 14 days. Blood pressures, heart rates, P-R intervals; and serum concentrations of R-/S-verapamil and norverapamil were measured multiple times in patients during the last day of each therapy. Median blood pressure decreased more with generic verapamil than with the brand-name drug, with the largest difference occurring at 0.5 hours (137/74 mmHg versus 144.5/80.5 mmHg; P = 0.05 and 0.091, respectively). Pharmacokinetic parameters were not different for the two products (P generic product, compared with the brand-name drug, had mean area under the concentration-time curve (time 0 to 12 hours) ratios (90% CI) of 1.09 (0.78-1.52), 1.16 (0.87-1.55) and 1.11 (0.81-1.52) for R-, S-, and total verapamil. Seventy concentration peaks (31 with the brand-name drug, 39 with the generic drug) appeared between 8 and 24 hours. Median percentages of increase of these peaks, compared with those of previous concentrations, were 48.3% and 36.3% for brand-name and generic drugs, respectively. Fifty of the 70 peaks (71%) were associated with a stereospecific concentration peak of norverapamil and, temporally, with meals. Our findings suggest that whereas the two verapamil products may not be bioequivalent by Food and Drug Administration criteria, the observed differences in effects were not clinically significant in this elderly population. Multiple concentration peaks after absorption were observed in all patients with both verapamil products and were perhaps related to enterohepatic recirculation.

Statistical parametric mapping for effects of verapamil on olfactory connections of rat brain in vivo using manganese-enhanced MR imaging

International Nuclear Information System (INIS)

Soma, Tsutomu; Kurakawa, Masami; Koto, Daichi

2011-01-01

We investigated the effect of verapamil on the transport of manganese in the olfactory connections of rat brains in vivo using statistical parametric mapping and manganese-enhanced magnetic resonance (MR) imaging. We divided 12 7-week-old male Sprague-Dawley rats into 2 groups of six and injected 10 μL of saline into the right nasal cavities of the first group and 10 μL of verapamil (2.5 mg/mL) into the other group. Twenty minutes after the initial injection, we injected 10 μL of MnCl 2 (1 mol/L) into the right nasal cavities of both groups. We obtained serial T 1 -weighted MR images before administering the verapamil or saline and at 0.5, one, 24, 48, and 72 hours and 7 days after administering the MnCl 2 , spatially normalized the MR images on the rat brain atlas, and analyzed the data using voxel-based statistical comparison. Statistical parametric maps demonstrated the transport of manganese. Manganese ions created significant enhancement (t-score=36.6) 24 hours after MnCl 2 administration in the group administered saline but not at the same time point in the group receiving verapamil. The extent of significantly enhanced regions peaked at 72 hours in both groups and both sides of the brain. The peak of extent in the right side brain in the group injected with saline was 70.2 mm 3 and in the group with verapamil, 92.4 mm 3 . The extents in the left side were 64.0 mm 3 for the group with saline and 53.2 mm 3 for the group with verapamil. We applied statistical parametric mapping using manganese-enhanced MR imaging to demonstrate in vivo the transport of manganese in the olfactory connections of rat brains with and without verapamil and found that verapamil did affect this transport. (author)

Suppressive effects of diltiazem and verapamil on delayed rectifier K(+)-channel currents in murine thymocytes.

Science.gov (United States)

Baba, Asuka; Tachi, Masahiro; Maruyama, Yoshio; Kazama, Itsuro

2015-10-01

Lymphocytes predominantly express delayed rectifier K(+)-channels (Kv1.3) in their plasma membranes, and these channels play crucial roles in the lymphocyte activation and proliferation. Since diltiazem and verapamil, which are highly lipophilic Ca(2+) channel blockers (CCBs), exert relatively stronger immunomodulatory effects than the other types of CCBs, they would affect the Kv1.3-channel currents in lymphocytes. Employing the standard patch-clamp whole-cell recording technique in murine thymocytes, we examined the effects of these drugs on the channel currents and the membrane capacitance. Both diltiazem and verapamil significantly suppressed the peak and the pulse-end currents of the channels, although the effects of verapamil were more marked than those of diltiazem. Both drugs significantly lowered the membrane capacitance, indicating the interactions between the drugs and the plasma membranes. This study demonstrated for the first time that CCBs, such as diltiazem and verapamil, exert inhibitory effects on Kv1.3-channels expressed in lymphocytes. The effects of these drugs may be associated with the mechanisms of immunomodulation by which they decrease the production of inflammatory cytokines. Copyright © 2015 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Erythromycin potentiates PR interval prolonging effect of verapamil in the rat: A pharmacodynamic drug interaction

International Nuclear Information System (INIS)

Dakhel, Yaman; Jamali, Fakhreddin

2006-01-01

Calcium channel blockers and macrolide antibiotics account for many drug interactions. Anecdotal reports suggest interactions between the two resulting in severe side effects. We studied the interaction between verapamil and erythromycin in the rat to see whether it occurs at the pharmacokinetics or pharmacodynamic level. Adult male Sprague-Dawley rats received doses of 1 mg/kg verapamil or 100 mg/kg erythromycin alone or in combination (n = 6/group). Serial blood samples (0-6 h) were taken for determination of the drug concentrations using HPLC. Electrocardiograms were recorded (0-6 h) through subcutaneously inserted lead II. Binding of the drugs to plasma proteins was studied using spiked plasma. Verapamil prolonged PR but not QT interval. Erythromycin prolonged QT but not PR interval. The combination resulted in a significant increase in PR interval prolongation and AV node blocks but did not further prolong QT interval. Pharmacokinetics and protein binding of neither drug were altered by the other. Our rat data confirm the anecdotal human case reports that combination of erythromycin and verapamil can result in potentiation of the cardiovascular response. The interaction appears to be at the pharmacodynamic rather than pharmacokinetic level hence may be extrapolated to other calcium channel antagonists

Rapid solid-phase extraction method to quantify [{sup 11}C]-verapamil, and its [{sup 11}C]-metabolites, in human and macaque plasma

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Unadkat, Jashvant D. [Department of Pharmaceutics, University of Washington, Box 357610, Seattle, WA 98195 (United States)], E-mail: jash@u.washington.edu; Chung, Francisco; Sasongko, Lucy; Whittington, Dale; Eyal, Sara [Department of Pharmaceutics, University of Washington, Box 357610, Seattle, WA 98195 (United States); Mankoff, David [Department of Radiology, University of Washington, Box 356004, Seattle, WA 98195 (United States); Collier, Ann C. [Department of Medicine, University of Washington, Box 359929, Seattle, WA 98195 (United States); Muzi, Mark; Link, Jeanne [Department of Radiology, University of Washington, Box 356004, Seattle, WA 98195 (United States)

2008-11-15

Introduction: P-glycoprotein (P-gp), an efflux transporter, is a significant barrier to drug entry into the brain and the fetus. The positron emission tomography (PET) ligand, [{sup 11}C]-verapamil, has been used to measure in vivo P-gp activity at various tissue-blood barriers of humans and animals. Since verapamil is extensively metabolized in vivo, it is important to quantify the extent of verapamil metabolism in order to interpret such P-gp activity. Therefore, we developed a rapid solid-phase extraction (SPE) method to separate, and then quantify, verapamil and its radiolabeled metabolites in plasma. Methods: Using high-performance liquid chromatography (HPLC), we established that the major identifiable circulating radioactive metabolite of [{sup 11}C]-verapamil in plasma of humans and the nonhuman primate, Macaca nemestrina, was [{sup 11}C]-D-617/717. Using sequential and differential pH elution on C{sub 8} SPE cartridges, we developed a rapid method to separate [{sup 11}C]-verapamil and [{sup 11}C]-D-617/717. Recovery was measured by spiking the samples with the corresponding nonradioactive compounds and assaying these compounds by HPLC. Results: Verapamil and D-617/717 recovery with the SPE method was >85%. When the method was applied to PET studies in humans and nonhuman primates, significant plasma concentration of D-617/717 and unknown polar metabolite(s) were observed. The SPE and the HPLC methods were not significantly different in the quantification of verapamil and D-617/717. Conclusions: The SPE method simultaneously processes multiple samples in less than 5 min. Given the short half-life of [{sup 11}C], this method provides a valuable tool to rapidly determine the concentration of [{sup 11}C]-verapamil and its [{sup 11}C]-metabolites in human and nonhuman primate plasma.

Verapamil is Less Effective than Triamcinolone for Prevention of Keloid Scar Recurrence After Excision in a Randomized Controlled Trial

DEFF Research Database (Denmark)

Danielsen, Patricia L; Rea, Suzanne M; Wood, Fiona M

2016-01-01

per subject and each wound half randomized to receive intralesional injections of triamcinolone (10 mg/ml) or verapamil (2.5 mg/ml) at monthly intervals (4 doses). Interim analysis was performed after 14 subjects were completed. Survival analysis demonstrated significantly higher keloid recurrence...... with verapamil compared to triamcinolone 12 months post-surgery (log-rank test, p = 0.01) and higher overall risk of recurrence with verapamil (hazard ratio 8.44, 95% CI 1.62-44.05). The study was terminated early according to the stopping guideline (p safe but not as effective...

Differential antiepileptic effects of the organic calcium antagonists verapamil and flunarizine in neurons of organotypic neocortical explants from newborn rats

NARCIS (Netherlands)

Bingmann, D; Speckmann, E J; Baker, R E; Ruijter, J; de Jong, B. M.

1988-01-01

Effects of the organic calcium antagonists verapamil and flunarizine on pentylenetetrazol induced paroxysmal depolarizations were tested in organotypic neocortical explants taken from neonatal rats. In these in vitro experiments the papaverin derivative verapamil depressed, and finally abolished,

Uso do Verapamil em Gestantes Hipertensas Crônicas: análise do Fluxo das Artérias Uterinas e Umbilical Use of Verapamil in Chronic Hypertensive Pregnant Women: flow Analysis of Uterine Arteries and Umbilical Artery

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Marcus Jose do Amaral Vasconcellos

2000-06-01

Full Text Available Objetivo: este trabalho, utilizando verapamil, um bloqueador dos canais lentos de cálcio, constituiu ensaio clínico randomizado, duplo-cego e placebo controlado, e objetivou procurar variação do fluxo uteroplacentário e fetoplacentário durante uso oral crônico do fármaco em gestantes com hipertensão crônica leve para moderada. Métodos: 123 pacientes divididas em dois grupos: grupo estudo (n = 61, submetidas a 240 mg/dia de verapamil, e grupo controle (n = 62, submetidas ao placebo. As pacientes randomizadas em grupos de quatro utilizaram a medicação ou placebo durante trinta dias. Um exame do fluxo das artérias uterinas e da artéria umbilical pela dopplervelocimetria foi registrado. Pelo cálculo da média e desvio padrão, foram comparados os valores dos índices de resistência (IR e pulsatilidade (IP e da relação sístole/diástole (A/B das artérias em estudo após administração dos comprimidos. Resultados: o grupo verapamil apresentou os seguintes valores médios para as artérias uterinas: IR = 0,82 (0,28, IP de 1,06 (0,12 e A/B de 2,42 (0,51. O grupo placebo mostrou: IR de 0,75 (0,35, IP de 1,00 (0,18 e A/B de 2,30 (0,38. Quando analisada a artéria umbilical, os valores foram para o grupo verapamil: IR = 0,73 (0,12, IP = 1,04 (0,13 e A/B = 2,94 (0,32. No grupo placebo, IR = 0,70 (0,14, IP = 1,03 (0,07 e A/B = 3,02 (0,78. A análise estatística das diferenças das médias por meio da razão F mostrou não haver diferença entre os dois grupos avaliados. Conclusão: este trabalho referenda o uso do verapamil entre gestantes com hipertensão crônica (leve para moderada, pois não oferece prejuízos no fluxo uteroplacentário e fetoplacentário.Purpose: this study, using verapamil, a slow calcium channel blocker, was a randomized, clinical, double blind and placebo controlled trial, whose objective was to observe if there was a uteroplacental and fetoplacental flow variation during its chronic oral use. Methods: 123

Simultaneous determination of the intravenous and oral pharmacokinetic parameters of D,L-verapamil using stable isotope-labelled verapamil.

Science.gov (United States)

Eichelbaum, M; Somogyi, A; von Unruh, G E; Dengler, H J

1981-01-01

Following i.v. administration, the plasma concentration-time curve of verapamil could best be described by either a mono- or biexponential equation. Total plasma clearance (1.26 1/min) approached liver blood flow (1.51/min), so it can be concluded that its clearance is liver blood flow-dependent. Although absorption was almost complete after oral administration, absolute bioavailability (20%) was low, due to extensive hepatic first-pass metabolism. The approach using stable isotope-labelled and unlabelled drug permits simultaneous administration by the intravascular and extravascular routes, thus allowing determination of absolute bioavailability in a single experiment.

Verapamil eliminates the hierarchical nature of activation frequencies from the pulmonary veins to the atria during paroxysmal atrial fibrillation.

Science.gov (United States)

Kushiyama, Yasunori; Osaka, Toshiyuki; Yokoyama, Eriko; Hasebe, Hideyuki; Kuroda, Yusuke; Kamiya, Kaichiro; Kodama, Itsuo

2010-05-01

There is evidence that verapamil promotes the persistence of paroxysmal atrial fibrillation (AF). Little is known about the underlying mechanisms. The purpose of this study was to determine the effect of verapamil on dominant frequencies (DFs) in the pulmonary veins (PVs) and atria during paroxysmal AF with reference to its potential arrhythmogenicity. Forty-three patients with paroxysmal AF were studied. Bipolar electrograms were recorded simultaneously during AF from the right atrial free wall (RAFW), coronary sinus (CS) and three PVs, or two PVs and the left atrial appendage (LAA). The DFs were obtained by fast Fourier transform analysis before and after infusion of verapamil (0.1 mg/kg, intravenously). At baseline, the maximum DF among the PVs (6.9 +/- 0.9 Hz) was significantly higher than the DF in the RAFW (6.2 +/- 0.7 Hz), CS (5.7 +/- 0.5 Hz), or LAA (5.9 +/- 0.7 Hz) (Patrial DF gradient (RAFW 0.7 +/- 0.9, CS 1.1 +/- 0.7, LAA 0.7 +/- 0.9 Hz). Verapamil increased the atrial DF to 6.9 +/- 0.8, 6.6 +/- 0.7, and 7.2 +/- 1.0 Hz in the RAFW, CS, and LAA, respectively (Patrial DF gradient was eliminated after verapamil (RAFW 0.2 +/- 0.8, CS 0.5 +/- 0.6, LAA -0.4 +/- 0.8 Hz; Patrial DF gradient during paroxysmal AF. Copyright 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Dose calcium channel blocker verapamil decrease urinary VMA levels in sympathoadrenal hyperactive patients with posttraumatic stress disorder?

Institute of Scientific and Technical Information of China (English)

Munawar Alam Ansari; Shahida PAhmed; Zahida Memon

2008-01-01

Objective:The majority of the patients with posttraumatic stress disorders (PTSD)embrace augmented urina-ry flow of Vanillylmandelic Acid (VMA)than normal subjects owing to superior sympathetic doings,which steer to cardiovascular catastrophe.Urinary flow of VMA was evaluated as sympathoadrenal bustle marker in patients with posttraumatic stress disorder.Calcium ion shows a noteworthy dependability in nervousness owing to its special effects on brain synaptosomes.So this study was conducted to explore the effects of Verapamil on sympathoadrenal motion in patients with PTSD.Methods:Placebo controlled clinical tryout was conducted. At first hundred (100)PTSD patients were chosen and enrolled in the study,from department of Psychological Medicine Dow University of Health Sciences,Karachi.Verapamil 120 mg/day was specified in divided doses to group-I (n =50)patients and group-II (n =50)patients received placebo therapy on a daily basis for nine weeks.Each and every patient was monitored weekly,all the way through extent of study.Results:Under-neath the posttraumatic stress disorder,urinary excretion of VMA was greater.Calcium channel blocker vera-pamil additionally abolished the embellished retort in urinary flow of VMA appreciably in patients with PTSD. Conclusion:Verapamil was experiential to be exceedingly effectual treatment.It reduces VMA levels in u-rine,and on the whole cardiovascular threat in PTSD patients.

Comparative efficacy of intralesional verapamil hydrochloride and triamcinolone acetonide in hypertrophic scars and keloids.

Science.gov (United States)

Ahuja, Rajeev B; Chatterjee, Pallab

2014-06-01

There is not much level 1 evidence based literature to guide management of hypertrophic scars and keloids despite an array of therapeutic modalities at disposal. Intralesional (i/l) triamcinolone injections have remained a gold standard in non surgical management. Sporadic reports on use of i/l verapamil suggest its efficacy. Since verapamil has not found sufficient mention as an effective alternative modality, it was decided to undertake a randomized study which could also address some additional clinical parameters. A randomized, parallel group and observer blinded comparison with 40 patients (48 scars) was carried out to compare the effects of i/l triamcinolone (T) (22 scars) and verapamil injections (V) (26 scars). 1.5 ml was the maximum indicative volume decided in the study protocol for both the drugs (triamcinolone @40 mg/ml and verapamil @ 2.5 mg/ml). Patients included were aged between 15-60 years with scars ranging between 0.5-5 cm (but total area roughly scars under 2 years duration. Patients with keloidal diathesis were excluded. Injections were scheduled every three weeks until complete flattening of the scar or eight sessions, which ever came earlier. No concomitant therapies like massage, silicone gel or pressure garments were used. Scar evaluation at each stage was done by serial photographic records as well as by Vancouver Scar Scale (VSS). Comparative survival analysis between the two drugs was done using Kaplan Meier curves, and VSS scores were analyzed using Wilcoxon test and log rank test. Mean zero VSS scores were achieved with treatments in respect of scar height (T-12 weeks, V-21 weeks), vascularity (T-15 weeks, V-18 weeks) and pliability (T-15 weeks, V-21 weeks). The improvement in scar vascularity and pliability kept pace with decrease in scar height, in both the groups. There was not much difference in the rate of change of scar pigmentation with either drug but almost 60% patients in both the groups regained normal pigmentation. Our

Tariquidar-induced P-glycoprotein inhibition at the rat blood-brain barrier studied with (R)-11C-verapamil and PET.

Science.gov (United States)

Bankstahl, Jens P; Kuntner, Claudia; Abrahim, Aiman; Karch, Rudolf; Stanek, Johann; Wanek, Thomas; Wadsak, Wolfgang; Kletter, Kurt; Müller, Markus; Löscher, Wolfgang; Langer, Oliver

2008-08-01

The multidrug efflux transporter P-glycoprotein (P-gp) is expressed in high concentrations at the blood-brain barrier (BBB) and is believed to be implicated in resistance to central nervous system drugs. We used small-animal PET and (R)-11C-verapamil together with tariquidar, a new-generation P-gp modulator, to study the functional activity of P-gp at the BBB of rats. To enable a comparison with human PET data, we performed kinetic modeling to estimate the rate constants of radiotracer transport across the rat BBB. A group of 7 Wistar Unilever rats underwent paired (R)-11C-verapamil PET scans at an interval of 3 h: 1 baseline scan and 1 scan after intravenous injection of tariquidar (15 mg/kg, n = 5) or vehicle (n = 2). After tariquidar administration, the distribution volume (DV) of (R)-11C-verapamil was 12-fold higher than baseline (3.68 +/- 0.81 vs. 0.30 +/- 0.08; P = 0.0007, paired t test), whereas the DVs were essentially the same when only vehicle was administered. The increase in DV could be attributed mainly to an increased influx rate constant (K1) of (R)-11C-verapamil into the brain, which was about 8-fold higher after tariquidar. A dose-response assessment with tariquidar provided an estimated half-maximum effect dose of 8.4 +/- 9.5 mg/kg. Our data demonstrate that (R)-11C-verapamil PET combined with tariquidar administration is a promising approach to measure P-gp function at the BBB.

Comparative influence of propranolol and verapamil on glycemic control and histamine sensitivity associated with L-thyroxine-induced hyperthyroidism - an experimental study.

Science.gov (United States)

Bhatt, Parloop A; Makwana, Dharmesh

2008-02-01

The present investigation was undertaken to study the comparative effectiveness of beta-adrenergic antagonist propranolol and calcium channel blocker verapamil on L-thyroxine-induced alteration on glycemic control and histamine sensitivity on rats and guinea pigs, respectively. Injection of L-thyroxine sodium every alternate day for 3 weeks in guinea pigs (75 microg/kg, i.p.) and rats (75 mg/kg, s.c.) produced a condition similar to thyrotoxicosis. Verapamil and propranolol administered daily in the third week along with L-thyroxine to two separate groups of hyperthyroid animals reversed thyroxine-induced loss in body weight, reduction in serum TSH levels, and rise in body temperature. Effect on glucose metabolism and insulin sensitivity was studied on rats. Compared to normal rats, L-thyroxine-treated animals showed a state of hyperglycemia, hyperinsulinemia, impaired glucose tolerance, and insulin resistance. Propranolol (10 mg/kg, i.p.) treatment significantly decreased fasting serum glucose levels without affecting serum insulin levels, AUC glucose, and K(ITT) values. Treatment with verapamil (5 mg/kg, i.p.) significantly reduced fasting serum glucose and insulin levels, AUC glucose, and significantly increased K(ITT) values. Effect of propranolol (15 mg/kg, orally) and verapamil (20 mg/kg, orally) treatment on histamine sensitivity was studied on L-thyroxine-treated guinea pigs. Compared to normal guinea pigs, L-thyroxine-treated guinea pigs showed an increased sensitivity to histamine-induced asphyxia. Verapamil treatment reversed this increased histamine sensitivity while propranolol aggravated it. In conclusion, compared to propranolol, verapamil has advantageous effects on glucose metabolism, insulin and histamine sensitivity and could therefore be a valuable addition as an adjunctive therapy option currently available for thyrotoxicosis associated with diabetes and/or anaphylaxis.

Interaction of rivaroxaban with amiodarone, verapamil and diltiazem in patients with atrial fibrillation: terra incognita

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S. N. Bel'diev

2016-01-01

Full Text Available Currently there are no generally accepted guidelines for the use of rivaroxaban together with amiodarone, verapamil or diltiazem in patients with creatinine clearance (CrCl<80 ml/min. Some researchers suggest that in renal failure amiodarone, verapamil and diltiazem contribute to a significant increase in plasma concentrations of rivaroxaban that is accompanied by increased risk of bleeding. According to preliminary calculations, it seems rational to reduce the dose of rivaroxaban when co-administered with these drugs: to 15 mg/day in patients with ClCr 50-79 ml/min and to 10 mg/day in patients with ClCr<50 ml/min.

A combined accelerator mass spectrometry-positron emission tomography human microdose study with 14C- and 11C-labelled verapamil.

Science.gov (United States)

Wagner, Claudia C; Simpson, Marie; Zeitlinger, Markus; Bauer, Martin; Karch, Rudolf; Abrahim, Aiman; Feurstein, Thomas; Schütz, Matthias; Kletter, Kurt; Müller, Markus; Lappin, Graham; Langer, Oliver

2011-02-01

In microdose studies, the pharmacokinetic profile of a drug in blood after administration of a dose up to 100 μg is measured with sensitive analytical techniques, such as accelerator mass spectrometry (AMS). As most drugs exert their effect in tissue rather than blood, methodology is needed for extending pharmacokinetic analysis to different tissue compartments. In the present study, we combined, for the first time, AMS analysis with positron emission tomography (PET) in order to determine the pharmacokinetic profile of the model drug verapamil in plasma and brain of humans. In order to assess pharmacokinetic dose linearity of verapamil, data were acquired and compared after administration of an intravenous microdose and after an intravenous microdose administered concomitantly with an oral therapeutic dose. Six healthy male subjects received an intravenous microdose [0.05 mg] (period 1) and an intravenous microdose administered concomitantly with an oral therapeutic dose [80 mg] of verapamil (period 2) in a randomized, crossover, two-period study design. The intravenous dose was a mixture of (R/S)-[14C]verapamil and (R)-[11C]verapamil and the oral dose was unlabelled racaemic verapamil. Brain distribution of radioactivity was measured with PET whereas plasma pharmacokinetics of (R)- and (S)-verapamil were determined with AMS. PET data were analysed by pharmacokinetic modelling to estimate the rate constants for transfer (k) of radioactivity across the blood-brain barrier. Most pharmacokinetic parameters of (R)- and (S)-verapamil as well as parameters describing exchange of radioactivity between plasma and brain (influx rate constant [K(1)] = 0.030 ± 0.003 and 0.031 ± 0.005 mL/mL/min and efflux rate constant [k(2)] = 0.099 ± 0.006 and 0.095 ± 0.008 min-1 for period 1 and 2, respectively) were not statistically different between the two periods although there was a trend for nonlinear pharmacokinetics for the (R)-enantiomer. On the other hand, all

The effect of verapamil as an adjuvant agent with local anesthetic on sensory block level, hemodynamic and postoperative pain

International Nuclear Information System (INIS)

Tabaeizavareh, M.H.; Omranifard, M.

2012-01-01

Objective: Coadministration of verapamil with local anesthetics could potentiate the sensory block of peripheral nerve, increase the duration of sensory nerve block and reduce postoperative pain and analgesic consumption. The aim of this study was to investigate the effect of verapamil as an adjuvant with bupivacaine on level of sensory block, post-operative pain and analgesic consumption among patients undergone elective surgery in Isfahan. Methodology: In this prospective randomized interventional clinical double-blind study ASA physical status I or II male patients referred for elective lower abdominal surgery were enrolled. They randomized in group A (20 cc of 0.5% bupivacaine plus 5 mg verapamil) and B(20 cc of 0.5% bupivacaine plus 2 cc normal saline). The sensory level block, postoperative pain, opioid consumption and vomiting and nausa and hemodynamic state was recorded and compared in two groups. Results: Sixty two patients were studied. Mean of the sensory level block 20 minutes after stating epidural anesthesia and immediately after surgery, postoperative pain score, opioid consumption and nausea and vomiting and fluid intake was not significantly different in two groups (P>0.05). Mean of systolic and diastolic blood pressure and pulse rate changes was not significantly different in two groups (P>0.05). Conclusion: Verapamil as an adjuvant with bupivacaine could not significantly increase the level of sensory block and attenuate post-operative pain and analgesic consumption and hemodynamic condition of the patients. For more accurate results it is recommended to determine the effect of different dose of verapamil in larger sample size of the patients. Studying the effect of other Ca channel blockers would be favorable in this regard. (author)

Mensuration of cardioangiopulmonary indices by radiocardiogram before and after the verapamil oral administration in subjects with chronic obstructive pulmonary disease. Mensuracao de indices cardiangiopulmonares, atraves do radiocardiograma antes e apos o emprego de verapamil por via oral em portadores de molestia pulmonar obstrutiva cronica

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Lara, P F [Sao Paulo Univ., SP (Brazil). Inst. de Ciencias Biomedicas; Hueb, W A [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina

1982-11-01

Twenty subjects with chronic obstructive pulmonary disease were studied. The diagnosis was obtained from the history, clinical evaluation, pulmonary radiography, pulmonary and hepatic scintigraphies and spirometry. About 360 mg of verapamil was administered daily, every eight hours for ten days. Before and after drug administration, the arterial pressures, the spirometric measurements and nine cardiac roentgenographic indexes were measured. Vital capacity increased in all cases, but did not reach the normal levels. These data suggest that the effect of verapamil on the pulmonary circulation brought benefits to the subjects. This occurred either by direct pulmonary vasodilation, or by bronchodilation, reducing hypoxia. In all cases, the pulmonary resistance was diminished. Finally, verapamil seems to be a drug with real benefits in subjects with chronic obstructive pulmonary disease and we advise a continuation of the studies. (author).

Efecto de la ciclosporina A y el verapamil en el pancreas endocrino de ratas

Directory of Open Access Journals (Sweden)

Nuris Ledón Naranjo

1995-08-01

Full Text Available Se demostró el efecto tóxico de la ciclosporina A (10 mg/kg sobre las células ß- pancreáticas, al ser suministrada diariamente durante una semana a ratas Wistar, así como la reducción de su toxicidad por tratamiento conjunto de verapamil (1 mg/kg. El tratamiento con ciclosporina A produjo hiperglicemia, disminuyó la tolerancia a la glucosa y los niveles de insulina, lo que ocasionó una reducción del incremento de peso en las ratas. Desde el punto de vista ultraestructural, se observó desorden y destrucción celular. Se concluyó que el tratamiento con ciclosporina A y verapamil simultáneamente evitó los efectos tóxicos de la ciclosporina A.

Mensuration of cardioangiopulmonary indices by radiocardiogram before and after the verapamil oral administration in subjects with chronic obstructive pulmonary disease

International Nuclear Information System (INIS)

Lara, P.F.; Hueb, W.A.

1982-01-01

Twenty subjects with chronic obstructive pulmonary disease were studied. The diagnosis was obtained from the history, clinical evaluation, pulmonary radiography, pulmonary and hepatic scintigraphies and spirometry. About 360 mg of verapamil was administered daily, every eight hours for ten days. Before and after drug administration, the arterial pressures, the spirometric measurements and nine cardiac roentgenographic indexes were measured. Vital capacity increased in all cases, but did not reach the normal levels. These data suggest that the effect of verapamil on the pulmonary circulation brought benefits to the subjects. This occurred either by direct pulmonary vasodilation, or by bronchodilation, reducing hypoxia. In all cases, the pulmonary resistance was diminished. Finally, verapamil seems to be a drug with real benefits in subjects with chronic obstructive pulmonary disease and we advise a continuation of the studies. (author)

Bodipy-FL-Verapamil: A Fluorescent Probe for the Study of Multidrug Resistance Proteins

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Anna Rosati

2004-01-01

Full Text Available Most of the substances used as fluorescent probes to study drug transport and the effect of efflux blockers in multidrug resistant cells have many drawbacks, such as toxicity, unspecific background, accumulation in mitochondria. New fluorescent compounds, among which Bodipy‐FL‐verapamil (BV, have been therefore proposed as more useful tools. The uptake of BV has been evaluated by cytofluorimetry and fluorescence microscopy using cell lines that overexpress P‐glycoprotein (P388/ADR and LLC‐PK1/ADR or MRP (multidrug resistance‐related protein (PANC‐1 and clinical specimens from patients. The effect of specific inhibitors for P‐glycoprotein (verapamil and vinblastine or MRP (MK571 and probenecid has been also studied. BV intracellular concentrations were significantly lower in the two P‐glycoprotein overexpressing cell lines in comparison with the parental lines. In addition, verapamil and vinblastine increased the intracellular concentrations of the dye; MK571 and probenecid, two MRP inhibitors, increased BV levels in PANC‐1 cells, that express this protein. These findings were confirmed in clinical specimens from patients. Fluorescence microscopy revealed a faint fluorescence emission in P‐glycoprotein or MRP expressing cell lines; however, treatment with specific inhibitors significantly increased the fluorescence. BV is a useful tool for studying multidrug resistance proteins with different techniques such as cytofluorimetry and fluorescence microscopy, but does not discriminate between P‐glycoprotein and MRP. In comparison with other classic fluorescent probes, the assay with this dye is extremely rapid, simple, not toxic for cells, devoid of fluorescent background, and can be useful in the clinical settings.

The putative P-gp inhibitor telmisartan does not affect the transcellular permeability and cellular uptake of the calcium channel antagonist verapamil in the P-glycoprotein expressing cell line MDCK II MDR1

DEFF Research Database (Denmark)

Saaby, Lasse; Tfelt-Hansen, Peer; Brodin, Birger

2015-01-01

monolayers with a permeability of 5.7 × 10−5 cm sec−1 compared to an apical to basolateral permeability of 1.3 × 10−5 cm sec-1. The efflux could be inhibited with the P-gp inhibitor zosuquidar. Zosuquidar (0.4 μmol/L) reduced the efflux ratio (PB-A/PA-B) for verapamil 4.6–1.6. The presence of telmisartan......Verapamil is used in high doses for the treatment of cluster headache. Verapamil has been described as a P-glycoprotein (P-gp, ABCB1) substrate. We wished to evaluate in vitro whether co administration of a P-gp inhibitor with verapamil could be a feasible strategy for increasing CNS uptake...... of verapamil. Fluxes of radiolabelled verapamil across MDCK II MDR1 monolayers were measured in the absence and presence of the putative P-gp inhibitor telmisartan (a clinically approved drug compound). Verapamil displayed a vectorial basolateral-to-apical transepithelial efflux across the MDCK II MDR1...

MICROMORPHOLOGICALCHARACTERISTICS OF THE LIVER AND BIOCHEMICAL ANALYSES IN THE BLOOD OF RATS TREATED BY GENTAMICIN AND VERAPAMIL

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Milan Stoiljkovic

2006-04-01

Full Text Available The use of antimicrobial drugs, especially gentamicin and calcium blocker verapamil, may cause transitional functional damage of the liver.The aim of this study is to explore micro-morphological changes in the liver and biochemical changes in the blood of rats treated with gentamicin and verapamil. The research included 20 rats divided in experimental and control group. The experimental group (10 rats was treated with gentamicin (100 mg/kg/BW/24h and verapamil (3 mg/kgBW/24 h for 8 days. The control group (10 rats received physiological solution (1 ml/kgBW/24 h at the same time. We analyzed micro-morphological changes in the liver and biochemical parameters in blood: transaminase, bilirubin and glucose.In the control group, there was a normal lobular liver structure. All hepatocytes had polygonal shape, pink cytoplasm and the location of nucleus was central or paracentral. Biochemical blood analysis showed normal level of transaminase (SGOT 29.5 +/- 7.4 iu/l; SGPT 31.7 +/- 6.9 iu/l, total bilirubin (3.1 +/- 0.9 mmol/l and glucose (4.9 +/- 0.9 mmol/l. In the experimental group of animals, hepatocytes of all three zones were equally damaged. In the cytoplasm, we found vacuolar degeneration, reduced condensation of chromatine in nucleus and light nucleoplasm. Hepatocytes of the periportal zone had acidofillic degeneration, picnotic and hiperchromatic nuclei. Biochemical blood analysis showed high level of transaminase (SGOT 46.4 +/- 4.7 iu/l; SGPT 50.8+/-6.1 iu/l, total bilirubin (12.8+/-1.7 mmol/l and glucose (9.3+/-1.8 mmol/l. There is a statistically significant difference in biochemical parameters between the two groups (p < 0,001. The results of our experimental study suggest that there is an obvious correlation between application of gentamicin and verapamil and these changes.

Environmental levels of 239+240Pu and 90Sr for internal radiation exposure assessment

International Nuclear Information System (INIS)

Anand, S.J.S.; Khandekar, R.N.; Krishnamoorthy, T.M.

1995-01-01

Measurements have been carried out on the concentration of low levels of long-lived isotopes of 239+240 Pu and 90 Sr in the environmental materials such as atmospheric particulates, drinking water and food. The estimation of daily intake of these isotopes through inhalation and ingestion is a pre-requisite for the assessment of internal exposure. This paper presents temporal distribution of 239+240 Pu and 90 Sr in rain water, drinking water and total diet samples collected at Trombay site. The annual committed effective dose due to 90 Sr through inhalation and diet to the population of Bombay has been estimated to be 0.06 nSv/y and 0.48 μSv/y, respectively, and the same for 239+240 Pu is 1.3 nSv/y and 0.9 nSv/y, respectively. The data is discussed in relation to previous years' values to assess for any significant increase. (author). 9 refs., 3 figs., 2 tabs

The structurally novel Ca2+ channel blocker Ro 40-5967, which binds to the [3H] desmethoxyverapamil receptor, is devoid of the negative inotropic effects of verapamil in normal and failing rat hearts

International Nuclear Information System (INIS)

Clozel, J.P.; Veniant, M.; Osterrieder, W.

1990-01-01

Ro 40-5967 is a structurally novel Ca 2+ channel blocker that binds to the verapamil-type receptor of cardiac membranes but that has been shown in isolated guinea-pig hearts to be about ten times less potent a negative inotropic agent than verapamil. The goals of the present study were to confirm these findings in vitro in isolated perfused rat hearts as well as in vivo in conscious rats and to compare Ro 40-5967 to verapamil. The effects of Ro 40-5967 and verapamil were tested not only in normal rats, but also in rats with heart failure induced by chronic myocardial infarction. In isolated Langendorff hearts (without heart failure), no decrease of contractility was observed with Ro 40-5967 up to complete AV block. In contrast, verapamil decreased contractility with an IC50 of 100 nM. In isolated, electrically stimulated rat papillary muscles, the IC50 values for the decrease of contractile force were 15,000 and 440 nM for Ro 40-5967 and verapamil, respectively. In vivo, Ro 40-5967 did not decrease left ventricular contractility (as assessed by changes of dP/dt max +) in rats without and with heart failure. In contrast, verapamil was markedly negative inotropic in both conditions

A Report of Brugada Syndrome Presenting with Cardiac Arrest Triggered by Verapamil Intoxication.

Science.gov (United States)

Yakut, Kahraman; Erdoğan, İlkay; Varan, Birgül; Atar, İlyas

2017-12-01

Brugada syndrome is a disease characterized by a specific electrocardiographic pattern and an increased risk of sudden cardiac death. We present this case with the updated literature to emphasise the need to consider the diagnosis of Brugada syndrome in patients admitted to the emergency ward with sudden cardiac arrest. A 16-year-old female patient was admitted to the emergency ward with complaints of weakness and abdominal pain, and she had four cardiac arrests during her evaluation period. She was referred to our clinic for permanent pacemaker implantation. She was on a temporary pace maker after having had C-reactive protein. Her physical exam was normal except for bilaterally decreased lung sounds. Lung x-ray and computed tomography, which were performed by another institution, revealed minimal pleural effusion and nothing else of significance. Blood and peritoneal fluid samples were sterile. Echocardiographic exam and cardiac enzymes were also in the normal ranges. Electrocardiographic showed incomplete right branch block in leads V1 and V2. An ajmaline test revealed specific electrocardiographic findings of the type I Brugada pattern. We proposed implanting an implantable cardioverter defibrillator to the patient as there were positive findings on the ajmaline test as well as a history of sudden cardiac arrest. After this treatment proposal, the patient's family admitted that she had taken a high dose of verapamil and thus, the encountered bradycardia was associated with verapamil overuse. The ajmaline test was repeated as it was contemplated that the previous positive ajmaline test had been associated with verapamil overuse. Implantable cardioverter defibrillator implantation was proposed again as there was a history of sudden cardiac arrest; however, the family did not consent to implantable cardioverter defibrillator, and the patient was discharged and followed up. Brugada syndrome should be considered for patients who are admitted to the emergency ward

A study of internal dosimetry of Am-241 and Sr-90 by dismantling of a nuclear installation; Eine Fallstudie zur internen Dosimetrie von Am-241 und Sr-90 bei Rueckbau einer kerntechnischen Anlage

Energy Technology Data Exchange (ETDEWEB)

Froning, M.; Hill, P. [Forschungszentrum Juelich GmbH (Germany). Geschaeftsbereich Sicherheit und Strahlenschutz

2016-07-01

During dismantling operation in former nuclear facility routine incorporation monitoring had been part of the safety measures. For an occupational radiation worker positive measurements results for {sup 241}Am, {sup 90}Sr and {sup 137}Cs were obtained after the end of the working period. Follow up monitoring had been performed assessing urine and faeces samples for {sup 241}Am and {sup 90}Sr as well as in-vivo measurements for {sup 137}Cs. Ingestion could be proven as incorporation path. The internal dose assessment according to GMBl 2007{sup [1]} finally yielded internal dose at 13 μSv.

Analgesia Synergism of Essential Oil from Pericarp of Zanthoxylum schinifolium and Verapamil

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Gao Wu

2014-01-01

Full Text Available Objective. To evaluate the synergistic analgesic effect of essential oil of Zanthoxylum schinifolium Sieb. et Zucc. (EOZ and verapamil (Ver. Method. The qualitative and quantitative composition of EOZ were determined with gas chromatography/Mass spectrometer. The interaction between EOZ and Ver in antinociceptive activity was evaluated by using acetic acid-induced writhing, hot plate, and tail flick tests in mice and in isolated toad sciatic nerve test. Results. Linalool, limonene, and sabinene are the major components of EOZ. EOZ (middle-dose: 40 mg·kg−1, high-dose: 80 mg·kg−1 and EOZ + Ver (Each dose group have remarkable analgesic effects on pain in mice induced by acetic acid-induced writhing, hot plate, and tail flick tests. Low-dose EOZ (20 mg·kg−1 had no analgesic action, but when it is combined with Ver it has shown significant antinociception. Verapamil has a faint analgesic effect but was not able to inhibit action potential transmission in toad sciatic nerve. EOZ (0.2% and EOZ + Ver (0.2% + 0.05% also inhibited action potential transmission in toad sciatic nerve. Combination of EOZ with Ver had a greater analgesic effect and inhibition of nerve action potential transmission compared to its components EOZ and Ver. Conclusion. The combination of EOZ with Ver produces a synergistic analgesic effect.

A case of internal contamination by 90Sr of a member of public

International Nuclear Information System (INIS)

Malatova, I.; Cespirova, I.; Drabova, D.; Beckova, V.

1998-01-01

A case of internal contamination by 90 Sr of a member of the public is described. An unauthorised person entered a low-activity waste storage placed in an abandoned sand mine, a barrel with marker for radioactive substances was found and manipulated with a tin labelled as ISOMET Sr90. The radiation protection authority was informed after 6 days and found surface contamination on his belongings. Whole-body counting with an HPGe detector and excretion analysis were performed. He was measured by whole-body counter 16 times from November 1990 to August 1992, 9 samples of urine and 6 samples of faeces were collected. For the estimation of the dose, the software CINDY with the biokinetic models of ICRP 30 was used. Single and continuous intakes were assumed. Intake was estimated to be about 3 MBq and committed effective dose 84 mSv. (author)

Toxic effects, bioconcentration and depuration of verapamil in the early life stages of common carp (Cyprinus carpio L.)

Czech Academy of Sciences Publication Activity Database

Steinbach, C.; Fedorova, G.; Prokeš, Miroslav; Grabicová, K.; Máchová, J.; Grabic, R.; Valentová, O.; Kocour Kroupová, H.

461-462, 461-462 (2013), s. 198-206 ISSN 0048-9697 Institutional support: RVO:68081766 Keywords : Bioconcentration * Embryo-larval test * Half-life time * Heart rate * Verapamil Subject RIV: GL - Fishing Impact factor: 3.163, year: 2013

Alginate prevention of internal irradiation with 90Sr

International Nuclear Information System (INIS)

Korzun, V.N.; Voronova, Yu.G.; Parats, A.N.; Podkorytova, A.V.; Rogal'skaya, L.A.; Saglo, V.I.; Skorikova, A.I.

1992-01-01

Recipes of foodstaffs (meat and vegetable preserves, bread, pastry, dairy products, etc.) containing sodium or calcium alginates in doses 0.5-3.0 g have been developed. Experiments with white rats have demonstrated that addition of such products to daily radions of these animals reduced 2-4-fold the accumulation of radioactive Sr taken daily with food for 30 days. Alginates and Crambe added to food preserve their ability to reduce the accumulation of radioactive Sr

A Report of Brugada Syndrome Presenting with Cardiac Arrest Triggered by Verapamil Intoxication

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Kahraman Yakut

2017-12-01

Full Text Available Background: Brugada syndrome is a disease characterized by a specific electrocardiographic pattern and an increased risk of sudden cardiac death. We present this case with the updated literature to emphasise the need to consider the diagnosis of Brugada syndrome in patients admitted to the emergency ward with sudden cardiac arrest. Case Report: A 16-year-old female patient was admitted to the emergency ward with complaints of weakness and abdominal pain, and she had four cardiac arrests during her evaluation period. She was referred to our clinic for permanent pacemaker implantation. She was on a temporary pace maker after having had C-reactive protein. Her physical exam was normal except for bilaterally decreased lung sounds. Lung x-ray and computed tomography, which were performed by another institution, revealed minimal pleural effusion and nothing else of significance. Blood and peritoneal fluid samples were sterile. Echocardiographic exam and cardiac enzymes were also in the normal ranges. Electrocardiographic showed incomplete right branch block in leads V1 and V2. An ajmaline test revealed specific electrocardiographic findings of the type I Brugada pattern. We proposed implanting an implantable cardioverter defibrillator to the patient as there were positive findings on the ajmaline test as well as a history of sudden cardiac arrest. After this treatment proposal, the patient’s family admitted that she had taken a high dose of verapamil and thus, the encountered bradycardia was associated with verapamil overuse. The ajmaline test was repeated as it was contemplated that the previous positive ajmaline test had been associated with verapamil overuse. Implantable cardioverter defibrillator implantation was proposed again as there was a history of sudden cardiac arrest; however, the family did not consent to implantable cardioverter defibrillator, and the patient was discharged and followed up. Conclusion: Brugada syndrome should be

Determination of doxazosin and verapamil in human serum by fast LC-MS/MS: Application to document non-compliance of patients

Czech Academy of Sciences Publication Activity Database

Chytil, L.; Štrauch, B.; Cvačka, Josef; Marešová, V.; Widimský jr., J.; Holaj, R.; Slanař, O.

2010-01-01

Roč. 878, č. 30 (2010), s. 3167-3173 ISSN 1570-0232 Institutional research plan: CEZ:AV0Z40550506 Keywords : doxazosin * verapamil * hypertension Subject RIV: CC - Organic Chemistry Impact factor: 2.971, year: 2010

A study on the action of two calcium channel blockers (verapamil and flunarizine upon an experimental model of tardive dyskinesia in rats

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João S. Pereira

1992-09-01

Full Text Available Tardive dyskinesia (TD, a serious complications of neuroleptic chronic use, has no effective therapy yet. We performed an experiment to study the action on TD, of the calcium channel blockers (CCB drugs, verapamil and flunarizine. We obtained the TD model in rats, administering haloperidol for a 21-day period. After this, the stereotyped movement induced by apomorphyne was rated. The CCB drugs were administered in acute (in the 28th. day and chronic (for 8 days, after the 25th day experiments. Acutely, verapamil increased the stereotyped behaviour, and promoted a reduction of it in the chronic experiment. The results suggest that CCB drugs should be tested in clinical trials of TD.

Structured Self-Rated Response to Iontophoresis with Verapamil and Dexamethasone in Peyronie’s Disease

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Abas Kokab

2014-01-01

Full Text Available Introduction. New therapies evolve for the treatment of Peyronie's disease (PD including the application of dexamethasone and verapamil using Electro Motive Drug Administration (EMDA. Patients and Methods. Patients with PD were routinely offered Potaba, Vitamin E, tamoxifen or colchicine for 6 to 18 months and for those with no improvement, 18 applications of dexamethasone and verapamil using EMDA occurred over a 6 week period. All 30 patients receiving EMDA therapy completed a questionnaire before and after treatment. The data was collected from December 2004 to November 2009 and analysed to evaluate the effectiveness of the treatment. Results. Median age of patients was 59 (range 39–71. Curvature was the most common presenting complaint (73.3% followed by pain (23.3%, erectile dysfunction (13.3%, and lump (13.3%. 24/30 (80% reported an improvement in symptoms after EMDA. 16 of the responders (66.7% had a stable plaque for at least 6 months. The patients who complained of shortening of the penis (P=0.003 or lowered sexual desire (P=0.024 expressed subsequently significant response to treatment. There was statistically significant (P=0.019 improvement of penile deviation reported by responding men. Conclusion. A significant proportion of patients who received EMDA reported decreased curvature following iontophoresis. No serious adverse reactions developed.

Cardiac autonomic tone during trandolapril-irbesartan low-dose combined therapy in hypertension: a pilot project.

Science.gov (United States)

Franchi, F; Lazzeri, C; Foschi, M; Tosti-Guerra, C; Barletta, G

2002-08-01

Pharmacological and clinical studies on the effects of angiotensin-converting enzyme (ACE) inhibitors support the idea of a central role played Angiotensin II which is able to cause cardiovascular and renal diseases also independently of its blood pressure elevating effects. The present investigation was aimed at evaluating the effect(s) of three different pharmacological regimens on both blood pressure and sympathetic drive in uncomplicated essential hypertension, by means of blood pressure laboratory measurements and ambulatory monitoring, 24-h heart rate variability and plasma noradrenaline levels. Thus, an ACE-inhibitor monotherapy (trandolapril, 2 mg/day), an AT(1)-receptor antagonist monotherapy (irbesartan, 300 mg/day), their low-dose combination (0.5 mg/day plus 150 mg/day, respectively) and placebo were given, in a randomised, single-blind, crossover fashion for a period of 3 weeks each to 12 mild essential hypertensives. Power spectral analysis (short recordings) and noradrenaline measurements were also performed in the supine position and after a postural challenge (60 degrees head-up tilting test: HUT). The low-dose combination therapy induced the greatest reduction in LF component and in LF/HF ratio, both in the resting and tilted positions, as well as in blood pressure. However, the physiological autonomic response to HUT was maintained. Noradrenaline plasma levels were lower after the combined therapy than after each drug alone. Our data demonstrate that in mild and uncomplicated essential hypertension, the chronic low-dose combination therapy with an ACE-inhibitor and an AT(1)-antagonist is more effective than the recommended full-dose monotherapy with either drug in influencing the autonomic regulation of the heart, suggesting a relative reduction in sympathetic drive both at cardiac and systemic levels.

Development and evaluation of controlled-release buccoadhesive verapamil hydrochloride tablets

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Emami J.

2008-05-01

Full Text Available Background and purpose of the study: Verapamil hydrochloride is a calcium channel blocker which is used in the control of supraventricular arrhythmia, hypertension and myocardial infraction. There are considerable inter-individual variations in serum concencentration of verpamil due to variation in the extent of hepatic metabolism. In this study controlled-release buccoadhesive tablets of verapamil hydrochloride (VPH were prepared in order to achieve constant plasma concentrations, to improve the bioavailability by the avoidance of hepatic first-pass metabolism, and to prevent frequent administration. Materials and methods: Tablets containing fixed amount of VPH were prepared by direct compression method using polymers like carbomer (CP, hydroxypropylmethyl cellulose (HPMC and sodium carboxymethyl cellulose (NaCMC in various combination and ratios and evaluated for thickness, weight variation, hardness, drug content uniformity, swelling, mucoadhesive strength, drug release and possible interaction between ingredients. Results: All tablets were acceptable with regard to thickness, weight variation, hardness, and drug content. The maximum bioadhesive strength was observed in tablets formulated with a combination of CP-NaCMC followed by CP-HPMC and NaCMC-HPMC.  Decreasing the content of CP in CP-HPMC tablets or NaCMC in CP-NaCMC or NaCMC-HPMC systems resulted in decrease in detachment forces. Lower release rates were observed by lowering the content of CP in CP-HPMC containing formulations or NaCMC in tablets which contained CP-NaCMC or NaCMC-HPMC. The release behavior was non-Fickian controlled by a combination of diffusion and chain relaxation mechanisms and best fitted zero-order kinetics. Conclusion: The buccoadhesive VPH tablets containing 53% CP and 13.3% HPMC showed suitable release kinetics (n = 0.78, K0 zero order release = 4.11 mg/h, MDT = 5.66 h and adhesive properties and did not show any interaction between polymers and drug based on

Evaluation Effects of Verapamil as a Calcium Channel Blocker on Acquisition, Consolidation and Retrieval of Memory in Mice

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Nooshin Masoudian

2015-04-01

Full Text Available Many factors are involved in learning and memory processes including brain nuclei, neurotransmitter systems, and the activity of ion channels. Studies showed inconsistent effects of calcium channel blockers on learning process, especially memory consolidation; however, little is known about their effect on memory acquisition and retrieval. Accordingly, the present study aimed to determine the effects of verapamil calcium channel antagonist as a representative of the phenylalkylamine group on different stages of memory and learning processes including acquisition, consolidation and retrieval in mice. In this experimental study, 150 male albino mice with a mean weight of 30 g were used. The mice were trained in a passive avoidance-learning task (1 mA shock for 2 seconds for evaluation of memory acquisition and consolidation and 3 seconds for evaluation of memory retrieval. The effect of verapamil (1, 2.5, 5, 10, and 20 mg/kg on memory consolidation and the most effective dose of consolidation phase on memory acquisition and retrieval was assessed. For the evaluation of memory consolidation, the animals received the drug intraperitoneally immediately after training, while for evaluation of memory acquisition and retrieval, the drug was injected one hour before training. Memory retrieval test was performed 48 hours after training (the length of time it took the animal to enter the dark part of the device. The results showed that verapamil injection exerted no effect on memory acquisition and consolidation; nevertheless, it was capable to disrupt memory retrieval in 10 and 20 mg doses. These results indicate that as a phenylalkylamine calcium channel antagonist, high doses of verapamil can impair memory. Normal 0 false false false EN-US X-NONE AR-SA /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso

Evaluation of intralesional injection of hyaluronic acid compared with verapamil in Peyronie's disease: preliminary results from a prospective, double-blinded, randomized study.

Science.gov (United States)

Favilla, V; Russo, G I; Zucchi, A; Siracusa, G; Privitera, S; Cimino, S; Madonia, M; Cai, T; Cavallini, G; Liguori, G; D'Achille, G; Silvani, M; Franco, G; Verze, P; Palmieri, A; Torrisi, B; Mirone, V; Morgia, G

2017-07-01

Several intralesional therapeutic protocols have been proposed for the treatment of Peyronie's disease. Among all, hyaluronic acid (HA) and verapamil have been differently tested. We aimed to evaluate the efficacy of intralesional verapamil (ILVI) compared with intralesional HA in patients with early onset of Peyronie's disease (PD). This is a multi-centre prospective double-arm, randomized, double-blinded study comparing ILVI vs. intralesional HA after 12-weeks. Sexually active men, older than 18 years and affected by the acute phase of PD were eligible for this study. Patients have been double-blinded randomly divided into two groups (1 : 1 ratio): Group A received intralesional treatment with Verapamil (10 mg in 5 mL of normal saline water) weekly for 12 weeks, while group B received intralesional treatment with HA (0.8% highly purified sodium salt HA 16 mg/2 mL) weekly for 12 weeks. The primary efficacy outcome was the change from the baseline to the endpoint (12 weeks after therapy) for the penile curvature (degree). The secondary outcome was the change in the plaque size and in the International Index of erectile Function (IIEF-5) score. The difference between post- and pre-treatment plaque size was -1.36 mm (SD ± 1.27) for Group A and -1.80 mm (SD ± 2.47) for Group B (p-value = NS). IIEF-5 increased of 1.46 points (SD ± 2.18) in Group A and 1.78 (SD ± 2.48) in Group B (p-value ± NS). No difference in penile curvature was observed in Group A, while in Group B the penile curvature decreased of 4.60° (SD ± 5.63) from the baseline (p < 0.001) and vs. Group A. According to PGI-I results, we found significant difference as concerning patient global impression of improvement (PGI-I) (4.0 vs. 2.0; p < 0.05). This prospective, double-arm, randomized, double-blinded study comparing ILVI vs. HA as intralesional therapy showed greater efficacy of HA in terms of penile curvature and PGI-I. © 2017 American Society of Andrology and

Age influence on retention, distribution and internal doses of 85Sr in rat

International Nuclear Information System (INIS)

Tian Wuxun; Wang Decheng; Zhang Hongyuan

1990-01-01

After I.V. 85 Sr, the whole body 85 Sr-retentions in rats were fit to two compartment exponential equations. The equation parameters showed a significantly difference between the young group and both the adult and old groups (p 2 ) for 85 Sr in the slow compartment decreased in regular order from the young to the old groups. In the bone 85 Sr-retention equations Tb 2 of the slow compartment for 85 Sr in the young group was significantly lower than the adult and old groups. The doses of the whole body and red-marrow for young rats were 4.2 times as much as those of adult rats, and 6.2 and 5.9 times as much as those old rats. The dose-cumulative speeds was most quick in the young groups and similar in the adult and the old

Evaluation of rate of swelling and erosion of verapamil (VRP) sustained-release matrix tablets.

Science.gov (United States)

Khamanga, Sandile M; Walker, Roderick B

2006-01-01

Tablets manufactured in-house were compared to a marketed sustained-release product of verapamil to investigate the rate of hydration, erosion, and drug-release mechanism by measuring the wet and subsequent dry weights of the products. Swelling and erosion rates depended on the polymer and granulating fluid used, which ultimately pointed to their permeability characteristics. Erosion rate of the marketed product was highest, which suggests that the gel layer that formed around these tablets was weak as opposed to the robust and resistant layers of test products. Anomalous and near zero-order transport mechanisms were dominant in tests and commercial product, respectively.

15-PGDH inhibitors: the antiulcer effects of carbenoxolone, pioglitazone and verapamil in indomethacin induced peptic ulcer rats.

Science.gov (United States)

Moustafa, Y M; El-Azab, M F; Fouda, A

2013-01-01

15-hydroxyprostaglandin dehydrogenase (15-PGDH) is the enzyme responsible for prostaglandins (PGs) metabolism. PGs have an important role in the protection of stomach mucosa against destructive stimuli. The aim of the present study is to investigate the inhibitory effect of carbenoxolone, pioglitazone and verapamil on 15-PGDH enzyme. The experiments were carried out in the Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt from May 2011 to August 2011. Adult male albino rats were fasted for 18 hours before administration of high dose of indomethacin (30 mg/kg, p.o.), except for the negative control group which received saline only, followed by pyloric ligation to induce acute gastric ulcers. The rats were pretreated orally with saline, pioglitazone (20 mg/kg), verapamil (25 mg/kg), carbenoxolone (30 mg/kg) or their combinations 30 minutes before indomethacin. The rats were sacrificed after four hours of pyloric ligation. The effects of the previous treatments on the ulcer index (Ui), the microscopic appearance of gastric mucosa, the gastric acid output, the gastric barrier mucus content, and 15-PGDH enzyme activity were determined. Indomethacin resulted in severe ulceration and increased gastric acid output (p ulcer index, gastric acid output and 15-PGDH activity (p ulcer index, gastric acid output and 15-PGDH activity (p stomach mucosa.

International co-operation

International Nuclear Information System (INIS)

1997-01-01

In 1996, Nuclear Regulatory Authority of the Slovak Republic (NRA SR) ensured the Slovak Republic (SR) obligations with relation to the international agreements and with the SR membership in the IAEA.International co-operation has been ensured on the basis of the bilateral international agreements. With the Ministry of Foreign Affairs co-operation, the SR fulfilled its financial obligations to this organization in due time and in the full scope. Representing Central and Eastern Europe interest in the Board of Governors, the SR participation in the highest executive in the highest executive authority was finished in 1996.The Board of Governors Vice-chairman position was executed by NRA SR Chairman. 5 national and 6 regional technical co-operation and assistance projects were realized in 1996. 12 organizations participated in these projects and accordingly 104 experts took part in training programmes, scientific visits or as the mission members abroad. Besides, Slovak experts participated at work of technical advisory and consultation groups with the significant assistance. In the framework of IAEA co-operation, the SR was visited by 11 expert missions formed by 28 experts from 19 countries including IAEA. Slovak organizations, namely institutes of the Academy of Sciences, Slovak research centres and universities participated in IAEA scientific and research activities through NRA SR. 15 scientific contracts in total were approved and realized and these contracts are utilized as supplementary financing of the own scientific and research projects. Other international co-operation and regional co-operation activities of the NRA SR in 1996 are reviewed

Part I. Naltrexone-derived conjugate addition ligands for opioid receptors. Part II. Chemical and enantioselective aspects of the metabolism of verapamil

International Nuclear Information System (INIS)

Olsen, L.D.

1987-01-01

Selective chemoaffinity ligands to aid in identification and purification of opioid receptor subtypes were prepared from 6α- and 6β-naltrexol, obtained stereoselectively from the μ-receptor antagonist naltrexone. The targets were the 6α- and 6β-methacrylate ethers and 6α- and 6β-methacrylate esters prepared from reaction of 6α- and 6β-naltrexol with methyl α-(bromomethyl)acrylate or methacryloyl chloride. Of three methacrylate derivatives, the 6α-ether was the most potent in an opioid receptor binding assay with [ 3 H]-naltrexone. In the presence of sodium ion, preincubation of the 6α-ether resulted in recovery of about 60% of original [ 3 H]-naltrexone binding suggesting some irreversible effects. The methacrylate esters precipitated withdrawal in morphine dependent monkeys. The enantiomers of verapamil, a calcium channel antagonist, have different pharmacological and pharmacokinetic properties. The oxidative metabolism of verapamil was studied in rat and human liver microsomes and in man after a single oral dose

(R-[11C]Verapamil PET studies to assess changes in P-glycoprotein expression and functionality in rat blood-brain barrier after exposure to kainate-induced status epilepticus

Directory of Open Access Journals (Sweden)

Lammertsma Adriaan A

2011-01-01

Full Text Available Abstract Background Increased functionality of efflux transporters at the blood-brain barrier may contribute to decreased drug concentrations at the target site in CNS diseases like epilepsy. In the rat, pharmacoresistant epilepsy can be mimicked by inducing status epilepticus by intraperitoneal injection of kainate, which leads to development of spontaneous seizures after 3 weeks to 3 months. The aim of this study was to investigate potential changes in P-glycoprotein (P-gp expression and functionality at an early stage after induction of status epilepticus by kainate. Methods (R-[11C]verapamil, which is currently the most frequently used positron emission tomography (PET ligand for determining P-gp functionality at the blood-brain barrier, was used in kainate and saline (control treated rats, at 7 days after treatment. To investigate the effect of P-gp on (R-[11C]verapamil brain distribution, both groups were studied without or with co-administration of the P-gp inhibitor tariquidar. P-gp expression was determined using immunohistochemistry in post mortem brains. (R-[11C]verapamil kinetics were analyzed with approaches common in PET research (Logan analysis, and compartmental modelling of individual profiles as well as by population mixed effects modelling (NONMEM. Results All data analysis approaches indicated only modest differences in brain distribution of (R-[11C]verapamil between saline and kainate treated rats, while tariquidar treatment in both groups resulted in a more than 10-fold increase. NONMEM provided most precise parameter estimates. P-gp expression was found to be similar for kainate and saline treated rats. Conclusions P-gp expression and functionality does not seem to change at early stage after induction of anticipated pharmacoresistant epilepsy by kainate.

(R)-[11C]Verapamil PET studies to assess changes in P-glycoprotein expression and functionality in rat blood-brain barrier after exposure to kainate-induced status epilepticus

International Nuclear Information System (INIS)

Syvänen, Stina; Luurtsema, Gert; Molthoff, Carla FM; Windhorst, Albert D; Huisman, Marc C; Lammertsma, Adriaan A; Voskuyl, Rob A; Lange, Elizabeth C de

2011-01-01

Increased functionality of efflux transporters at the blood-brain barrier may contribute to decreased drug concentrations at the target site in CNS diseases like epilepsy. In the rat, pharmacoresistant epilepsy can be mimicked by inducing status epilepticus by intraperitoneal injection of kainate, which leads to development of spontaneous seizures after 3 weeks to 3 months. The aim of this study was to investigate potential changes in P-glycoprotein (P-gp) expression and functionality at an early stage after induction of status epilepticus by kainate. (R)-[ 11 C]verapamil, which is currently the most frequently used positron emission tomography (PET) ligand for determining P-gp functionality at the blood-brain barrier, was used in kainate and saline (control) treated rats, at 7 days after treatment. To investigate the effect of P-gp on (R)-[ 11 C]verapamil brain distribution, both groups were studied without or with co-administration of the P-gp inhibitor tariquidar. P-gp expression was determined using immunohistochemistry in post mortem brains. (R)-[ 11 C]verapamil kinetics were analyzed with approaches common in PET research (Logan analysis, and compartmental modelling of individual profiles) as well as by population mixed effects modelling (NONMEM). All data analysis approaches indicated only modest differences in brain distribution of (R)-[ 11 C]verapamil between saline and kainate treated rats, while tariquidar treatment in both groups resulted in a more than 10-fold increase. NONMEM provided most precise parameter estimates. P-gp expression was found to be similar for kainate and saline treated rats. P-gp expression and functionality does not seem to change at early stage after induction of anticipated pharmacoresistant epilepsy by kainate

Evaluation Effects of Verapamil as a Calcium Channel Blocker on Acquisition, Consolidation and Retrieval of Memory in Mice

OpenAIRE

Nooshin Masoudian; Nahid Masoudian; Ali Rashidy Pour; Abbas Ali Vafaiee; Sasan Andalib; Golnaz Vaseghi

2015-01-01

Many factors are involved in learning and memory processes including brain nuclei, neurotransmitter systems, and the activity of ion channels. Studies showed inconsistent effects of calcium channel blockers on learning process, especially memory consolidation; however, little is known about their effect on memory acquisition and retrieval. Accordingly, the present study aimed to determine the effects of verapamil calcium channel antagonist as a representative of the phenylalkylamine group on ...

(R)-[{sup 11}C]Verapamil PET studies to assess changes in P-glycoprotein expression and functionality in rat blood-brain barrier after exposure to kainate-induced status epilepticus

Energy Technology Data Exchange (ETDEWEB)

Syvänen, Stina [Division of Pharmacology, LACDR, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Luurtsema, Gert [Department of Nuclear Medicine & Molecular Imaging, Groningen University Medical Center, P.O. Box 30.001 9700 RB Groningen (Netherlands); Molthoff, Carla FM; Windhorst, Albert D; Huisman, Marc C; Lammertsma, Adriaan A [Department of Nuclear Medicine & PET Research, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam (Netherlands); Voskuyl, Rob A [Division of Pharmacology, LACDR, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Epilepsy Institute of The Netherlands Foundation (SEIN), P.O. Box 21, 2100 AA, Heemstede (Netherlands); Lange, Elizabeth C de [Division of Pharmacology, LACDR, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands)

2011-01-03

Increased functionality of efflux transporters at the blood-brain barrier may contribute to decreased drug concentrations at the target site in CNS diseases like epilepsy. In the rat, pharmacoresistant epilepsy can be mimicked by inducing status epilepticus by intraperitoneal injection of kainate, which leads to development of spontaneous seizures after 3 weeks to 3 months. The aim of this study was to investigate potential changes in P-glycoprotein (P-gp) expression and functionality at an early stage after induction of status epilepticus by kainate. (R)-[{sup 11}C]verapamil, which is currently the most frequently used positron emission tomography (PET) ligand for determining P-gp functionality at the blood-brain barrier, was used in kainate and saline (control) treated rats, at 7 days after treatment. To investigate the effect of P-gp on (R)-[{sup 11}C]verapamil brain distribution, both groups were studied without or with co-administration of the P-gp inhibitor tariquidar. P-gp expression was determined using immunohistochemistry in post mortem brains. (R)-[{sup 11}C]verapamil kinetics were analyzed with approaches common in PET research (Logan analysis, and compartmental modelling of individual profiles) as well as by population mixed effects modelling (NONMEM). All data analysis approaches indicated only modest differences in brain distribution of (R)-[{sup 11}C]verapamil between saline and kainate treated rats, while tariquidar treatment in both groups resulted in a more than 10-fold increase. NONMEM provided most precise parameter estimates. P-gp expression was found to be similar for kainate and saline treated rats. P-gp expression and functionality does not seem to change at early stage after induction of anticipated pharmacoresistant epilepsy by kainate.

Internal contamination assessment, with regard to 90Sr, 134Cs, and 137Cs nuclei during nuclear accident

International Nuclear Information System (INIS)

Ayad, M.; Hanna, K.M.

2000-01-01

In case of nuclear reactor accident leading to the release of some radioactive isotopes in the plume, the sedimentation of its constituents on the ground causes surface contamination which consequently can be observed in the form of an internal contamination in the living biosphere. The migration of the radio nuclei from the soil to the plant root, stem, and the other edible parts is considered the main source for the contaminated foodstuffs used by the general public. In this work we have calculated the total accumulative internal dose for 9 0Sr, 1 34Cs, and 1 37Cs radio contaminants with regard to different public age groups (infant, child, and adult) due to an unexpected nuclear accident. In our calculations we have applied the protective measure inequality for the chosen standard group of foodstuffs, with respect to each age group of the public as well as the three indicated above radio nuclei. Our results indicated that the values of the calculated protective measures with regard to 9 0Sr, 1 37Cs, and 1 34Cs radio nuclei are increasing respectively for all age groups. In addition, we found that the ratio of the total protection measure values of all radio nuclei for different age groups still less than one which requires no intervention level procedures

International Expert Review of Sr-Can: Safety Assessment Methodology - External review contribution in support of SSI's and SKI's review of SR-Can

International Nuclear Information System (INIS)

Sagar, Budhi; Egan, Michael; Roehlig, Klaus-Juergen; Chapman, Neil; Wilmot, Roger

2008-03-01

In 2006, SKB published a safety assessment (SR-Can) as part of its work to support a licence application for the construction of a final repository for spent nuclear fuel. The purposes of the SR-Can project were stated in the main project report to be: 1. To make a first assessment of the safety of potential KBS-3 repositories at Forsmark and Laxemar to dispose of canisters as specified in the application for the encapsulation plant. 2. To provide feedback to design development, to SKB's research and development (R and D) programme, to further site investigations and to future safety assessments. 3. To foster a dialogue with the authorities that oversee SKB's activities, i.e. the Swedish Nuclear Power Inspectorate, SKI, and the Swedish Radiation Protection Authority, SSI, regarding interpretation of applicable regulations, as a preparation for the SR-Site project. To help inform their review of SKB's proposed approach to development of the longterm safety case, the authorities appointed three international expert review teams to carry out a review of SKB's SR-Can safety assessment report. Comments from one of these teams - the Safety Assessment Methodology (SAM) review team - are presented in this document. The SAM review team's scope of work included an examination of SKB's documentation of the assessment ('Long-term safety for KBS-3 Repositories at Forsmark and Laxemar - a first evaluation' and several supporting reports) and hearings with SKB staff and contractors, held in March 2007. As directed by SKI and SSI, the SAM review team focused on methodological aspects and sought to determine whether SKB's proposed safety assessment methodology is likely to be suitable for use in the future SR-Site and to assess its consistency with the Swedish regulatory framework. No specific evaluation of long-term safety or site acceptability was undertaken by any of the review teams. SKI and SSI's Terms of Reference for the SAM review team requested that consideration be given

Part I. Naltrexone-derived conjugate addition ligands for opioid receptors. Part II. Chemical and enantioselective aspects of the metabolism of verapamil

Energy Technology Data Exchange (ETDEWEB)

Olsen, L.D.

1987-01-01

Selective chemoaffinity ligands to aid in identification and purification of opioid receptor subtypes were prepared from 6..cap alpha..- and 6..beta..-naltrexol, obtained stereoselectively from the ..mu..-receptor antagonist naltrexone. The targets were the 6..cap alpha..- and 6..beta..-methacrylate ethers and 6..cap alpha..- and 6..beta..-methacrylate esters prepared from reaction of 6..cap alpha..- and 6..beta..-naltrexol with methyl ..cap alpha..-(bromomethyl)acrylate or methacryloyl chloride. Of three methacrylate derivatives, the 6..cap alpha..-ether was the most potent in an opioid receptor binding assay with (/sup 3/H)-naltrexone. In the presence of sodium ion, preincubation of the 6..cap alpha..-ether resulted in recovery of about 60% of original (/sup 3/H)-naltrexone binding suggesting some irreversible effects. The methacrylate esters precipitated withdrawal in morphine dependent monkeys. The enantiomers of verapamil, a calcium channel antagonist, have different pharmacological and pharmacokinetic properties. The oxidative metabolism of verapamil was studied in rat and human liver microsomes and in man after a single oral dose.

Temperature dependence of cardiac sarcoplasmic reticulum and sarcolemma in the ventricle of catfish (Clarias gariepinus

Directory of Open Access Journals (Sweden)

El-Sabry Abu-Amra

2015-10-01

The sarcolemmal Ca2+ contribution of activator Ca2+ was greater at a test temperature of 30 °C as assessed by verapamil. Whereas the SR-Ca2+ contribution was higher at 20 and 30 °C and a frequency rate of 0.2 and 0.4 Hz as assessed by caffeine and adrenaline, respectively. Bradykinin potentiating factor (BPF7 which was isolated from jelly fish (Cassiopea andromeda decreased the cardiac force developed at a frequency rate of 0.2 Hz and a temperature of 20 °C, whereas it increased the force developed at frequency rates of 0.2 and 0.4 Hz at 30 °C. These results indicate that BPF7 may act like verapamil in reducing the cardiac force through blocking the sarcolemmal Ca2+ channels at low temperature and like adrenaline in an increase of the cardiac force developed at warm temperature and the high frequency rate through stimulation of SR-Ca2+ activator. Therefore, this study indicates that the sarcolemmal Ca2+ influx and the SR-Ca2+ release contributors of activator Ca2+ for cardiac force development in the catfish heart were significantly greater at warm temperature and at the pacing frequency rates of 0.2 and 0.4 Hz as assessed by verapamil, adrenaline, caffeine and BPF7. However, the relative contribution of the sarcolemmal Ca2+ influx in the development of cardiac force in the catfish heart was greater than that of SR-Ca2+ release.

Colesevelam

Science.gov (United States)

... and, therefore, the oxygen supply to your heart, brain, and other parts of your body. Lowering your ... any of the following: anticoagulants such as warfarin, insulin, and and verapamil (Calan SR).if you are ...

Optimization of 90Sr/89Sr measurements

Directory of Open Access Journals (Sweden)

Legarda F.

2012-04-01

Full Text Available One of the key points in the double measurement method for the measurement of both, 89Sr and 90Sr, by using a proportional counter is the choice of the times at which the measurements should be done. In this paper, the formulae to calculate the 89Sr and 90Sr detection limits in conditions of radioactive equilibrium between 90Y and 90Sr are derived, and an analysis of them as a function of the time between the two measurements is done. The choice for the time of the second measurement is going to depend on the desired quality of the results to be obtained.

Impact of inhalational exposure to ethanol fuel on the pharmacokinetics of verapamil, ibuprofen and fluoxetine as in vivo probe drugs for CYP3A, CYP2C and CYP2D in rats.

Science.gov (United States)

Cardoso, Juciane Lauren Cavalcanti; Lanchote, Vera Lucia; Pereira, Maria Paula Marques; Capela, Jorge Manuel Vieira; de Moraes, Natália Valadares; Lepera, José Salvador

2015-10-01

Occupational toxicology and clinical pharmacology integration will be useful to understand potential exposure-drug interaction and to shape risk assessment strategies in order to improve occupational health. The aim of the present study was to evaluate the effect of exposure to ethanol fuel on in vivo activities of cytochrome P450 (CYP) isoenzymes CYP3A, CYP2C and CYP2D by the oral administration of the probe drugs verapamil, ibuprofen and fluoxetine. Male Wistar rats exposed to filtered air or to 2000 ppm ethanol in a nose-only inhalation chamber during (6 h/day, 5 days/week, 6 weeks) received single oral doses of 10 mg/kg verapamil or 25 mg/kg ibuprofen or 10 mg/kg fluoxetine. The enantiomers of verapamil, norverapamil, ibuprofen and fluoxetine in plasma were analyzed by LC-MS/MS. The area under the curve plasma concentration versus time extrapolated to infinity (AUC(0-∞)) was calculated using the Gauss-Laguerre quadrature. Inhalation exposure to ethanol reduces the AUC of both verapamil (approximately 2.7 fold) and norverapamil enantiomers (>2.5 fold), reduces the AUC(0-∞) of (+)-(S)-IBU (approximately 2 fold) and inhibits preferentially the metabolism of (-)-(R)-FLU. In conclusion, inhalation exposure of ethanol at a concentration of 2 TLV-STEL (6 h/day for 6 weeks) induces CYP3A and CYP2C but inhibits CYP2D in rats. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electronic properties and surface reactivity of SrO-terminated SrTiO3 and SrO-terminated iron-doped SrTiO3.

Science.gov (United States)

Staykov, Aleksandar; Tellez, Helena; Druce, John; Wu, Ji; Ishihara, Tatsumi; Kilner, John

2018-01-01

Surface reactivity and near-surface electronic properties of SrO-terminated SrTiO 3 and iron doped SrTiO 3 were studied with first principle methods. We have investigated the density of states (DOS) of bulk SrTiO 3 and compared it to DOS of iron-doped SrTiO 3 with different oxidation states of iron corresponding to varying oxygen vacancy content within the bulk material. The obtained bulk DOS was compared to near-surface DOS, i.e. surface states, for both SrO-terminated surface of SrTiO 3 and iron-doped SrTiO 3 . Electron density plots and electron density distribution through the entire slab models were investigated in order to understand the origin of surface electrons that can participate in oxygen reduction reaction. Furthermore, we have compared oxygen reduction reactions at elevated temperatures for SrO surfaces with and without oxygen vacancies. Our calculations demonstrate that the conduction band, which is formed mainly by the d-states of Ti, and Fe-induced states within the band gap of SrTiO 3 , are accessible only on TiO 2 terminated SrTiO 3 surface while the SrO-terminated surface introduces a tunneling barrier for the electrons populating the conductance band. First principle molecular dynamics demonstrated that at elevated temperatures the surface oxygen vacancies are essential for the oxygen reduction reaction.

Quantitative Comparison of Effects of Dofetilide, Sotalol, Quinidine, and Verapamil between Human Ex vivo Trabeculae and In silico Ventricular Models Incorporating Inter-Individual Action Potential Variability

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Oliver J. Britton

2017-08-01

Full Text Available Background:In silico modeling could soon become a mainstream method of pro-arrhythmic risk assessment in drug development. However, a lack of human-specific data and appropriate modeling techniques has previously prevented quantitative comparison of drug effects between in silico models and recordings from human cardiac preparations. Here, we directly compare changes in repolarization biomarkers caused by dofetilide, dl-sotalol, quinidine, and verapamil, between in silico populations of human ventricular cell models and ex vivo human ventricular trabeculae.Methods and Results:Ex vivo recordings from human ventricular trabeculae in control conditions were used to develop populations of in silico human ventricular cell models that integrated intra- and inter-individual variability in action potential (AP biomarker values. Models were based on the O'Hara-Rudy ventricular cardiomyocyte model, but integrated experimental AP variability through variation in underlying ionic conductances. Changes to AP duration, triangulation and early after-depolarization occurrence from application of the four drugs at multiple concentrations and pacing frequencies were compared between simulations and experiments. To assess the impact of variability in IC50 measurements, and the effects of including state-dependent drug binding dynamics, each drug simulation was repeated with two different IC50 datasets, and with both the original O'Hara-Rudy hERG model and a recently published state-dependent model of hERG and hERG block. For the selective hERG blockers dofetilide and sotalol, simulation predictions of AP prolongation and repolarization abnormality occurrence showed overall good agreement with experiments. However, for multichannel blockers quinidine and verapamil, simulations were not in agreement with experiments across all IC50 datasets and IKr block models tested. Quinidine simulations resulted in overprolonged APs and high incidence of repolarization

Interim FEP report for the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

Skagius, Kristina (ed.) [Kemakta Konsult AB, Stockholm (Sweden)

2004-08-01

This report describes the work with identification and structuring of features, events and processes (FEPs) that has been carried out within the scope of the SR-Can safety assessment up to the time of the interim reporting of the project. The overall objective of the work is to develop a database of features, events and processes in a format that would facilitate both a systematic analysis of FEPs and documentation of the FEP analysis as well as facilitate revisions and updates to be made in connection with new safety assessments. This overall objective also includes the development of procedures for a systematic FEP analysis as well as to apply these procedures in order to arrive at an SR-Can version of the FEP database. The work started by implementing the content of the SR 97 Process report into a database format suitable for import and processing of FEP information from other sources. The SR 97 version of the database was systematically audited against the NEA database with Project FEPs, version 1.2. In addition, an earlier audit of the SR 97 process report against the interaction matrices developed for a deep repository of the KBS-3 type was revisited and updated. Relevant FEPs from the audit were sorted into three main categories in the SR-Can database i) FEPs related to the initial states of the repository system, ii) FEPs related to internal processes of the repository system, and iii) FEPs related to external impacts on the repository system. These groups of FEPs were further processed for making decisions on how to handle these FEPs in the assessment. Biosphere processes were not included in the SR 97 Process report and there is thus not the same basis for updating these descriptions as for the engineered barriers and the geosphere. All biosphere FEPs from the audit have therefore been compiled in a single category in the database, but remain to be further handled. FEPs were also categorised as irrelevant or as being related to methodology on a general

Interim FEP report for the safety assessment SR-Can

International Nuclear Information System (INIS)

Skagius, Kristina

2004-08-01

This report describes the work with identification and structuring of features, events and processes (FEPs) that has been carried out within the scope of the SR-Can safety assessment up to the time of the interim reporting of the project. The overall objective of the work is to develop a database of features, events and processes in a format that would facilitate both a systematic analysis of FEPs and documentation of the FEP analysis as well as facilitate revisions and updates to be made in connection with new safety assessments. This overall objective also includes the development of procedures for a systematic FEP analysis as well as to apply these procedures in order to arrive at an SR-Can version of the FEP database. The work started by implementing the content of the SR 97 Process report into a database format suitable for import and processing of FEP information from other sources. The SR 97 version of the database was systematically audited against the NEA database with Project FEPs, version 1.2. In addition, an earlier audit of the SR 97 process report against the interaction matrices developed for a deep repository of the KBS-3 type was revisited and updated. Relevant FEPs from the audit were sorted into three main categories in the SR-Can database i) FEPs related to the initial states of the repository system, ii) FEPs related to internal processes of the repository system, and iii) FEPs related to external impacts on the repository system. These groups of FEPs were further processed for making decisions on how to handle these FEPs in the assessment. Biosphere processes were not included in the SR 97 Process report and there is thus not the same basis for updating these descriptions as for the engineered barriers and the geosphere. All biosphere FEPs from the audit have therefore been compiled in a single category in the database, but remain to be further handled. FEPs were also categorised as irrelevant or as being related to methodology on a general

Multidrug resistance circumvention by a new triazinoaminopiperidine derivative S9788 in vitro: definition of the optimal schedule and comparison with verapamil.

Science.gov (United States)

Julia, A. M.; Roché, H.; Berlion, M.; Lucas, C.; Milano, G.; Robert, J.; Bizzari, J. P.; Canal, P.

1994-01-01

The current work was undertaken to investigate the importance of exposure sequence and duration in achieving the maximum reversal action of S9788 on doxorubicin (DOX) cytotoxicity against cells that exhibit the (MDR) multidrug resistance phenotype: the MCF7/DOX cell line. Accumulation and release of DOX were examined in this cell line. The reversal effect was compared with that obtained with verapamil. S9788 activity was schedule dependent: when comparing incubation with S9788 before or after treatment with DOX, the best reversal factor was obtained in the case of a post-treatment incubation (65.6 +/- 7.7 vs 20.8 +/- 7.0). S9788 was a more potent modulating agent than verapamil, whatever the schedule of exposure of the cells to the reversal agent. The reversal of resistance after short-term DOX exposures was caused not only by prolonged cellular accumulation of DOX, but also by its prolonged retention after transfer of cells to DOX-free medium. A relationship was noted between cellular exposure to DOX and the cytotoxic effect, and so the reversal of resistance induced by S9788 appears to be directly linked to the level of cell exposure to DOX. This work provided a rationale for improving the schedule of administration of S9788 in clinical trials. PMID:8180016

FEP report for the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

2010-12-15

This report documents the analysis and processing of features, events and processes, FEPs, that has been carried out within the safety assessment SR-Site, and forms an important part of the reporting of the project. The main part of the work was conducted within the earlier safety assessment SR-Can, which was a preparatory stage for the SR-Site assessment. The overall objective of the FEP analysis and processing in both SR-Can and SR-Site included development of a database of features, events and processes, an SKB FEP database, in a format that facilitates both a systematic analysis of FEPs and documentation of that FEP analysis, as well as facilitating revisions and updates to be made in connection with new safety assessments. The primary objective in SR-Site was to establish an SR-Site FEP catalogue within the framework of the SKB FEP database. This FEP catalogue was required to contain all FEPs that needed to be handled in SR-Site and is an update of the corresponding SR-Can FEP catalogue that was established for the SR-Can assessment. The starting point for the handling of FEPs in SR-Site was the SR-Can version of the SKB FEP database and associated SR-Can reports. The SR-Can version of the SKB FEP database includes the SR-Can FEP catalogue, as well as the sources for the identification of FEPs in SR-Can, namely the SR 97 processes and variables, Project FEPs in the NEA International FEP database version 1.2 and matrix interactions in the Interaction matrices developed for a deep repository of the KBS-3 type. Since the completion of the FEP work within SR-Can, an updated electronic version, version 2.1, of the NEA FEP database has become available. Compared with version 1.2 of the NEA FEP database, version 2.1 contains FEPs from two more projects. As part of SR-Site, all new Project FEPs in version 2.1 of the NEA FEP database have been mapped according to the methodology adopted in SR-Can resulting in an SR-Site version of the SKB FEP database. The SKB FEP

FEP report for the safety assessment SR-Site

International Nuclear Information System (INIS)

2010-12-01

This report documents the analysis and processing of features, events and processes, FEPs, that has been carried out within the safety assessment SR-Site, and forms an important part of the reporting of the project. The main part of the work was conducted within the earlier safety assessment SR-Can, which was a preparatory stage for the SR-Site assessment. The overall objective of the FEP analysis and processing in both SR-Can and SR-Site included development of a database of features, events and processes, an SKB FEP database, in a format that facilitates both a systematic analysis of FEPs and documentation of that FEP analysis, as well as facilitating revisions and updates to be made in connection with new safety assessments. The primary objective in SR-Site was to establish an SR-Site FEP catalogue within the framework of the SKB FEP database. This FEP catalogue was required to contain all FEPs that needed to be handled in SR-Site and is an update of the corresponding SR-Can FEP catalogue that was established for the SR-Can assessment. The starting point for the handling of FEPs in SR-Site was the SR-Can version of the SKB FEP database and associated SR-Can reports. The SR-Can version of the SKB FEP database includes the SR-Can FEP catalogue, as well as the sources for the identification of FEPs in SR-Can, namely the SR 97 processes and variables, Project FEPs in the NEA International FEP database version 1.2 and matrix interactions in the Interaction matrices developed for a deep repository of the KBS-3 type. Since the completion of the FEP work within SR-Can, an updated electronic version, version 2.1, of the NEA FEP database has become available. Compared with version 1.2 of the NEA FEP database, version 2.1 contains FEPs from two more projects. As part of SR-Site, all new Project FEPs in version 2.1 of the NEA FEP database have been mapped according to the methodology adopted in SR-Can resulting in an SR-Site version of the SKB FEP database. The SKB FEP

Effects of combination treatment with losartan and trandolapril on office and ambulatory blood pressures in non-diabetic renal disease: a COOPERATE-ABP substudy.

Science.gov (United States)

Nakao, Naoyuki; Seno, Hachiro; Kasuga, Hirotake; Toriyama, Takanobu; Kawahara, Hirohisa; Fukagawa, Masafumi

2004-01-01

In the COOPERATE trial, the combination treatment of the angiotensin-II receptor blocker losartan and the angiotensin-converting-enzyme inhibitor trandolapril significantly retarded progression of non-diabetic kidney disease compared with each monotherapy. The benefit could be greatly attributable to the potent reduction of proteinuria, because the three treatment groups showed the same reductions of office blood pressure (OBP). Ambulatory blood pressure (ABP) is reported to be better than OBP in predicting progression of kidney disease. Ninety-two patients enrolled in the COOPERATE trial underwent 24-hour ABP monitoring at randomization and at month 6, year 1, year 2 and year 3 on randomized treatment. Both OBP and ABP were similarly reduced among the three groups at all measurement points (p = NS) and throughout the whole study period (p = NS). No significant correlation between the change in 24-hour ABP and the change in proteinuria was seen (p = NS). A Cox-multivariable analysis showed that covariates affecting the renal outcomes (a doubling serum-Cr level and/or end-stage renal failure) were the change in proteinuria (hazard ratio 0.49, 95% CI 0.34-0.78, p = 0.01) and treatments (0.58, 0.45-0.99, 0.03), but not 24-hour ABP (0.98, 0.89-2.01, 0.17). The better renoprotective effect of the combination treatment is attributed to BP-independent mechanisms by more complete renin-angiotensin system blockade. 2004 S. Karger AG, Basel

A study of internal contamination, using 137Cs and 90Sr urinary level, as indicator in the case of nuclear accident

International Nuclear Information System (INIS)

Albulescu, L.; Gruia, D.

1996-01-01

Our laboratory has from long time a permanent monitoring programme concerning the radioactivity of the environmental factors in Bechet zone (fallout, drinking water, soil) and foodstuffs. The topical results of this programme indicates that there were not significant modifications in the 137 Cs and 90 Sr mean-levels, as indicators in case of nuclear accident, due by Chernobyl accident or by the nearby functioning of NPP in Koslodui. The purpose of this study is to determine the internal contamination of the population in Dolj-district, using the indirect test of determination of radioactivity of excretes (urinary analysis). The daily-urinary levels of 90 Sr and 137 Cs are the best indicators for the human body contamination, in the case of a nuclear accident, conclusion that can be drawn from the Fig.1 below. The variation of these indicators shows that the young people is the most exposed segment of population. (author)

Real-time {sup 90}Sr Counter

Energy Technology Data Exchange (ETDEWEB)

Kaneko, Naomi; Kawai, Hideyuki; Kodama, Satoshi; Kobayashi, Atsushi; Tabata, Makoto; Ito, Hiroshi [Graduate School of Science, Chiba University, Chiba, (Japan); Han, Soorim [Graduate School of Science, Chiba University, Chiba, (Japan); National Institute of Radiological Science, Chiba, (Japan)

2015-07-01

Radioisotopes have been emitted around Japan due to a nuclear accident at the Fukushima Daiichi nuclear power station in March 2011. A problem is the contaminated water including the atomic nucleus which relatively has a long half- life time and soluble such as {sup 90}Sr, {sup 137}Cs. Internal exposures by {sup 90}Sr are more dangerous than {sup 137}Cs's because Sr has effective half-life time of 18 years and property of accumulation in a born. We have developed real-time {sup 90}Sr counter which is sensitive beta-ray of maximum kinematic energy of 2.28 MeV from {sup 90}Sr and insensitive of beta-ray of maximum kinematic energy of 1.17 MeV and gamma-ray from {sup 90}Sr by Cherenkov detection. This counter composes of Cerenkov counter, trigger scintillation counter and veto counter. Silica aerogel for Cherenkov counter can obtain refractive index between 1.017 and 1.049 easily. And wavelength shifting fiber (WLSF) is used as a light guide for extending effective area and producing lower cost. A mechanism of the identification of {sup 90}Sr is explained in following. In case of {sup 90}Sr, when the trigger counter reacts on the beta-ray from {sup 90}Sr, aerogel emits the Cherenkov light and WLSF reacts and read the Cherenkov light. On the other hand, in case of {sup 137}Cs, the trigger counter reacts on the beta-ray, aerogel stops the beta- ray and Cherenkov light is not emitted. Therefore, aerogel has a function as a radiator and shielding material. the gamma-ray is not reacted on the lower density detector. Cosmic rays would be also reacted by the veto counter. A prototype counter whose the effective area is 30 cm x 10 cm was obtained (2.0±1.2){sup 3} of mis-identification as {sup 137}Cs/{sup 90}Sr. Detection limit in the surface contamination inspection depends on measurement time and effective area mainly. The sensitivity of wide range, 10{sup -2} - 10{sup 4} Bq/cm{sup 2}, is obtained by adjustment of detection level in circuit of this counter. A lower

International Expert Review of Sr-Can: Safety Assessment Methodology - External review contribution in support of SSI's and SKI's review of SR-Can

Energy Technology Data Exchange (ETDEWEB)

Sagar, Budhi (Center for Nuclear Waste Regulatory Analyses, Southwest Research Inst., San Antonio, TX (US)); Egan, Michael (Quintessa Limited, Henley-on-Thames (GB)); Roehlig, Klaus-Juergen (Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (DE)); Chapman, Neil (Independent Consultant (XX)); Wilmot, Roger (Galson Sciences Limited, Oakham (GB))

2008-03-15

In 2006, SKB published a safety assessment (SR-Can) as part of its work to support a licence application for the construction of a final repository for spent nuclear fuel. The purposes of the SR-Can project were stated in the main project report to be: 1. To make a first assessment of the safety of potential KBS-3 repositories at Forsmark and Laxemar to dispose of canisters as specified in the application for the encapsulation plant. 2. To provide feedback to design development, to SKB's research and development (R and D) programme, to further site investigations and to future safety assessments. 3. To foster a dialogue with the authorities that oversee SKB's activities, i.e. the Swedish Nuclear Power Inspectorate, SKI, and the Swedish Radiation Protection Authority, SSI, regarding interpretation of applicable regulations, as a preparation for the SR-Site project. To help inform their review of SKB's proposed approach to development of the longterm safety case, the authorities appointed three international expert review teams to carry out a review of SKB's SR-Can safety assessment report. Comments from one of these teams - the Safety Assessment Methodology (SAM) review team - are presented in this document. The SAM review team's scope of work included an examination of SKB's documentation of the assessment ('Long-term safety for KBS-3 Repositories at Forsmark and Laxemar - a first evaluation' and several supporting reports) and hearings with SKB staff and contractors, held in March 2007. As directed by SKI and SSI, the SAM review team focused on methodological aspects and sought to determine whether SKB's proposed safety assessment methodology is likely to be suitable for use in the future SR-Site and to assess its consistency with the Swedish regulatory framework. No specific evaluation of long-term safety or site acceptability was undertaken by any of the review teams. SKI and SSI's Terms of Reference for the SAM

An EPR investigation of the dynamic Jahn-Teller effect in SrCl2:y(2 plus) and SrCl2:Sc(2 plus)

Science.gov (United States)

Herrington, J. R.; Estle, T. L.; Boatner, L. A.

1972-01-01

EPR spectra have been observed for SrCl2:Y(2+) and SrCl2:Sc(2+) at liquid helium temperatures. At 1.2 K the spectra were dominated by anisotropic hyperfine patterns whose lineshapes and angular dependences were explained using second order solutions of the effective Hamiltonian for an isolated 2Eg state split by large random internal strains. Pronounced asymmetries in some of the strin produced lineshapes for Srcl2:Sc(2+) are shown to result from second order terms in the solution of the effective Hamiltonian. Coexisting with the anisotropic hyperfine patterns are weak nearly isotropic hyperfine patterns with typical lineshapes. Variations in the apparent intensity of lines in these weak hyperfine patterns as functions of the applied magnetic field direction and temperature imply that these lines result from averaging by vibronic relaxation of a portion of the anisotropic pattern. The effective Hamiltonian parameters for SrCl2:La(2+), SrCl2:y(2+), and SrCl2:SC(2+) are analyzed in terms of crystal field theory modified to include a dynamic Jahn-Teller effect.

Sequential separation of cs, ca and ba for 90sr assessment

International Nuclear Information System (INIS)

Dianu, M.; Bucur, C.

2015-01-01

A two-steps chemical treatment technique for strontium assessment from aqueous samples is described in this paper. The method was applied to simulated samples containing stable elements of Ni, Cs, Ca, Ba, Mn, Fe, Co and Eu. The transition elements (Ni, Mn, Fe, Co, Eu) were precipitated as hydroxides, followed by alkaline-earth metals separation (Ca, Ba) as carbonates. Finally, the Sr was purified by extraction chromatography using Triskem International Sr resin. The strength of Sr sorption in nitric acid increases with increasing acid concentration, and the optimal bonding strength is achieved in 8 M HNO3. The combination of successive precipitations with extraction chromatography for complete removal of other interferences from Sr matrix leads to good recovery and decontamination factor values. (authors)

Beta dosimetry in teeth from SR-90 exposed subjects

International Nuclear Information System (INIS)

Fattibene, P.; De Coste, V.; Onori, S.; Veronese, I.; Giussani, A.; Cantone, M.C.; Shishkina, E.

2006-01-01

Tooth enamel is a well recognized dosimeter for retrospective dose reconstruction of individuals accidentally exposed to ionizing radiation. The measurements of the absorbed dose in tooth enamel is conventionally carried out with the Electron Paramagnetic Resonance technique. Tooth enamel is sensitive to all kind of ionizing radiation. Its response to photons has been widely investigated. For application to contaminated teeth with 90 Sr, one of the most common osteo tropic radionuclides, the effectiveness of tooth enamel response to the β spectrum needs be evaluated. The response function to 90 Sr of the EPR/tooth enamel systems, its linearity and reproducibility have been investigated under a controlled geometry, and the results will be presented and compared to those obtained with photons. When the subject has been exposed to both external and internal radiation, a combined EPR/T.L. method can be used to distinguish the internal from the external contribution to the cumulative dose in tooth (Gosku et al., 2002;=Veronese et al. 2004, Shishkina et al. 2005). The T.L. measurement, performed putting thin ± Al 2 O 3 :C dosimeters at contact with the tooth surfaces, enables to estimate the beta dose rate due to the radionuclides present in tooth. The combination of this information with that coming from EPR allows, under specific assumptions, to evaluate separately the internal and external contribution to the tooth dose. In a previous work (Veronese et al., 2004) the dose in enamel measured by EPR in a tooth contaminated with 90 Sr of a Techa River resident was compared to the dose rate measured by TLDs. The test has been extended to a larger number of 90 Sr contaminated teeth. EPR measurements have been also performed in other portions of the teeth, i.e. tooth dentin and root. The correlation between the results, obtained from EPR and TLD measurements, and the evaluation of the relative proportion of internal and external dose are presented and discussed. (authors)

Laser ablation inductively coupled plasma mass spectrometry. An alternative technique for monitoring 90Sr

International Nuclear Information System (INIS)

TsingHai Wang; Yan-Chen Lai; Yi-Kong Hsieh; Chu-Fang Wang

2017-01-01

Developing a rapid detection method for monitoring released 90 Sr remains a challenge to analytical chemists, particularly considering its low concentration and significant interferences in environmental samples. We proposed a concept as an alternative to detect 90 Sr on the surface of fish scales using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The high affinity of fish scales to Sr is capable of preconcentrating 90 Sr that minimizes isobaric interferences from 90 Zr + or 89 YH + , while tailing effect by abundant 88 Sr can be effectively reduced by adjusting the forward power of ICP-MS component. Adopting dried droplets of internal standards further allows a semiquantification of 90 Sr content on the surface of fish scales, which also arises an opportunity to monitoring the bioaccumulation of 90 Sr after Fukushima Daiichi nuclear disaster. (author)

Measurement of the internal bremsstrahlung spectrum of a 89Sr beta emitter in the 1–100 keV photon energy regime

International Nuclear Information System (INIS)

Singh, Amrit; Dhaliwal, A.S.

2015-01-01

The internal bremsstrahlung (IB) spectrum of 89 Sr, which is a unique first forbidden beta emitter, is studied in the 1–100 keV photon energy regime. The IB spectrum is experimentally measured using a Si(Li) detector, which is efficient in this photon energy regime, and is compared with the IB distributions that are predicted by the Knipp, Uhlenbeck and Bloch (KUB), Nilsson, and Lewis and Ford theories. In the soft energy regime up to 15 keV, the measured results are in agreement with all the aforementioned theories. However, from 16–30 keV, the experimental results are in agreement with the Lewis and Ford theory, which applies to forbidden transitions, and at higher photon energies, the Nilsson theory best describes the measured results. The differences among the different theories also increase with the photon energy. The effect of the electrostatic Coulomb field on the IB process for beta emitters with different end-point energies is investigated by comparing the ratio of the IB probabilities predicted using the KUB and Nilsson theories for 35 S and 89 Sr, i.e., soft and hard beta emitters, respectively. The Coulomb effect is shown to be significant in the high photon energy regime and for beta emitters with low end-point energies. - Highlights: • Internal bremsstrahlung spectrum of 89 Sr, a unique first forbidden beta emitter, is studied. • The measurements are taken in the photon energy regions of 1–100 keV with Si(Li) detector. • The measured results are deviating from Lewis and Ford theory and are close to the Nilsson theory. • The effect of Coulomb field on the IB process for different end point energy sources is investigated. • Effect of Coulomb field is more for low energy beta emitter towards the high energy end

Anti-ischemic intervention as prognosis improvement in patients with coronary artery disease, with special focus on verapamil

DEFF Research Database (Denmark)

Jespersen, C M

1996-01-01

dysfunction, and thereby heart failure. In postinfarction patients intervention with verapamil significantly reduced the use of diuretics compared with placebo, indicating that anti-ischemic intervention may prevent heart failure. Ventricular arrhythmias are significantly associated with arrhythmic as well...... as non-arrhythmic death. The lack of preferential association of ventricular arrhythmias with arrhythmic death rather than nonarrhythmic death may imply that arrhythmias are provoked by ischemia. Antiarrhythmic intervention in postinfarction patients significantly increases death and arrhythmic events...... compared with placebo, especially in patients with residual ischemia. This may be due to a significant slowing of conduction during ischemia in patients treated with antiarrhythmic agents. In animal studies anti-ischemic agents prevent or suppress ventricular arrhythmias during ischemia, whereas...

Metastable honeycomb SrTiO_3/SrIrO_3 heterostructures

International Nuclear Information System (INIS)

Anderson, T. J.; Ryu, S.; Podkaminer, J. P.; Ma, Y.; Eom, C. B.; Zhou, H.; Xie, L.; Irwin, J.; Rzchowski, M. S.; Pan, X. Q.

2016-01-01

Recent theory predictions of exotic band topologies in (111) honeycomb perovskite SrIrO_3 layers sandwiched between SrTiO_3 have garnered much attention in the condensed matter physics and materials communities. However, perovskite SrIrO_3 film growth in the (111) direction remains unreported, as efforts to synthesize pure SrIrO_3 on (111) perovskite substrates have yielded films with monoclinic symmetry rather than the perovskite structure required by theory predictions. In this study, we report the synthesis of ultra-thin metastable perovskite SrIrO_3 films capped with SrTiO_3 grown on (111) SrTiO_3 substrates by pulsed laser deposition. The atomic structure of the ultra-thin films was examined with scanning transmission electron microscopy (STEM), which suggests a perovskite layering distinct from the bulk SrIrO_3 monoclinic phase. In-plane 3-fold symmetry for the entire heterostructure was confirmed using synchrotron surface X-ray diffraction to measure symmetry equivalent crystal truncation rods. Our findings demonstrate the ability to stabilize (111) honeycomb perovskite SrIrO_3, which provides an experimental avenue to probe the phenomena predicted for this material system.

FEP report for the safety assessment SR-Can

International Nuclear Information System (INIS)

Skagius, Kristina

2006-11-01

This report documents the analysis and processing of features, events and processes, FEPs, that has been carried out within the safety assessment SR-Can, and forms an important part of the reporting of the project. The SR-Can project is a preparatory stage for the SR-Site assessment, and the report from that project will be used in support of SKB's application to build a final repository. The overall objective of the FEP analysis and processing included development of a database of features, events and processes, an SKB FEP database, in a format that facilitates both a systematic analysis of FEPs and documentation of that FEP analysis, as well as facilitating revisions and updates to be made in connection with new safety assessments. The overall objective also extended to the development of procedures for such a systematic FEP analysis as well as the application of those procedures in order to establish an SR-Can FEP catalogue within the framework of the SKB FEP database. The work started by implementing the content of the SR 97 Process Report into a database format suitable for import and processing of FEP information from other sources. The SR 97 version of the database was systematically audited against the NEA database with Project FEPs, version 1.2. In addition, an earlier audit of the SR 97 process report against the interaction matrices developed for a deep repository of the KBS-3 type was revisited and updated. Relevant FEPs identified through the audit process were sorted into three main categories i) FEPs related to the initial states of the repository system, ii) FEPs related to internal processes of the repository system, and iii) FEPs related to external impacts on the repository system. This resulted in additions to the SR 97 list of processes and to the lists of initial state FEPs and external factors to be addressed in further processing. The further processing of the initial state FEPs revealed that those FEPs that are not covered by the

Experiences with the determination of Sr-89 and Sr-90 using fast methods; Erfahrungen bei der Bestimmung von {sup 89}Sr und {sup 90}Sr mittels Schnellmethoden

Energy Technology Data Exchange (ETDEWEB)

Kowalik, C.; Fueger, J. [Thueringer Landesanstalt fuer Umwelt und Geologie, Jena (Germany). Landesmessstelle fuer Umweltradioaktivaet

2014-01-20

Quick methods of the measurement of {sup 89}Sr and {sup 90}Sr have a great importance in the supervision of the environmental radioactivity. It is necessary to receive in short time dependable analytical data to be able to carry out suitable assessments or to give recommendations. The aim of the investigations was to be guaranteed the demands for these methods (test preparation, measurement and evaluation). The use of the solid phase extraction by means of commercial Sr Resin trademark columns (4.4' (5')-Di-tert-butylcyclohexanol-18-kronen-6-aether) (Triskem) to the radiochemical separation of the Sr isotopes was suitable. The measurements occurred to the FHT 770 T12 - Multi Low Level Alpha/Beta Sample Counter (Thermo Scientific). The results contain the summary activities of all available Sr isotopes, as for example {sup 89}Sr and {sup 90}Sr. The calculations of the single activities occur about the mathematical algorithm of the linear development on the basis of the works of G. Kanisch. The first results show, this method is suitable for the analysis of {sup 89}Sr and {sup 90}Sr and is used therefore in future in Thuringia.

Low leakage stoichiometric SrTiO{sub 3} dielectric for advanced metal-insulator-metal capacitors

Energy Technology Data Exchange (ETDEWEB)

Popovici, Mihaela; Kaczer, Ben; Redolfi, Augusto; Elshocht, Sven van; Jurczak, Malgorzata [imec Belgium, Leuven (Belgium); Afanas' ev, Valeri V. [Department of Physics and Astronomy, KU Leuven (Belgium); Sereni, Gabriele [DISMI, Universita degli Studi di Modena e Reggio Emilia, (Italy); Larcher, Luca [DISMI, Universita degli Studi di Modena e Reggio Emilia, (Italy); MDLab, Saint Christophe (Italy)

2016-05-15

Metal-insulator-metal capacitors (MIMCAP) with stoichiometric SrTiO{sub 3} dielectric were deposited stacking two strontium titanate (STO) layers, followed by intermixing the grain determining Sr-rich STO seed layer, with the Ti-rich STO top layer. The resulted stoichiometric SrTiO{sub 3} would have a structure with less defects as demonstrated by internal photoemission experiments. Consequently, the leakage current density is lower compared to Sr-rich STO which allow further equivalent oxide thickness downscaling. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Expert Opinion in SR 97 and the SKI/SSI Joint Review of SR 97

Energy Technology Data Exchange (ETDEWEB)

Hora, Stephen

2002-09-01

The role of sensitivity and uncertainty analyses for radioactive waste disposal assessments is reviewed. The report covers a description of the these concepts were applied in the authorities' review of the safety report SR 97. With regard to the use of expert knowledge, the most significant weakness of SR 97 is absence of any standards, procedures, and even definitions for expert judgment. This situation needs to be dealt with by SKB in the near future as it denigrates the portions of the study that are well done. In developing expert judgment processes, SSI should ensure that SKB creates procedures that guarantee traceability and transparency. This will become very important as the repository system matures and receives greater public scrutiny. Both in the area of scenario creation and expert judgement, there are processes that have gained international acceptance. It would be in the best interest of SKB, and the public, to adhere these accepted approaches.

Expert Opinion in SR 97 and the SKI/SSI Joint Review of SR 97

International Nuclear Information System (INIS)

Hora, Stephen

2002-09-01

The role of sensitivity and uncertainty analyses for radioactive waste disposal assessments is reviewed. The report covers a description of the these concepts were applied in the authorities' review of the safety report SR 97. With regard to the use of expert knowledge, the most significant weakness of SR 97 is absence of any standards, procedures, and even definitions for expert judgment. This situation needs to be dealt with by SKB in the near future as it denigrates the portions of the study that are well done. In developing expert judgment processes, SSI should ensure that SKB creates procedures that guarantee traceability and transparency. This will become very important as the repository system matures and receives greater public scrutiny. Both in the area of scenario creation and expert judgement, there are processes that have gained international acceptance. It would be in the best interest of SKB, and the public, to adhere these accepted approaches

Rapid method for determining Sr-89 and Sr-90 using Cherenkov and proportional counting; Schnellmethode zur Bestimmung von SR-89 und SR-90 durch Cerenkov- und Proportionalzaehlermessungen

Energy Technology Data Exchange (ETDEWEB)

Lange, S.; Wende, C.; Schwokowski, R.; Alisch-Mark, M.; Abraham, A.; Heinrich, T. [Staatliche Betriebsgesellschaft fuer Umwelt und Landwirtschaft, Radebeul (Germany)

2016-07-01

A rapid method for determining Sr-89 and Sr-90 in water, milk and biological samples has been developed and tested. After sample preparation strontium is separated by extraction chromatography using Sr resin. Eluate is divided and transfered to LSC vial and filter paper by SrCO{sub 3} precipitation. A Hidex 300 SL TDCR liquid scintillation counter and Thermo Fisher low level proportional counter have been used. Chemical yield of Sr-85 tracer is determined by Gamma spectroscopy. Uncertainty budget, decision threshold and detection limit are calculated in accordance with GUM and ISO 11929.

Level and dynamics of internal dose from 137Cs and 90Sr formation in connection with ecological diversity of polluted agrogenoses of Ukraine

International Nuclear Information System (INIS)

Kravets, A.P.; Grodzinsky, D.M.; Pavlenko, Yu.A.

2004-01-01

The purpose of our calculations was estimation of quantitative influence of ecological diversity on levels and dynamics of internal doses formation from long-lived radionuclide such as 137 Cs and 90 Sr. Our estimations have radioecological nature that is they are based on registration of natural mechanisms of agricultural products pollution. It has been realized on the basis of three-module ecological model of assessment of radiological consequences (EMARC) of use of polluted agrocenoses

S1P in HDL promotes interaction between SR-BI and S1PR1 and activates S1PR1-mediated biological functions: calcium flux and S1PR1 internalization[S

Science.gov (United States)

Lee, Mi-Hye; Appleton, Kathryn M.; El-Shewy, Hesham M.; Sorci-Thomas, Mary G.; Thomas, Michael J.; Lopes-Virella, Maria F.; Luttrell, Louis M.; Hammad, Samar M.; Klein, Richard L.

2017-01-01

HDL normally transports about 50–70% of plasma sphingosine 1-phosphate (S1P), and the S1P in HDL reportedly mediates several HDL-associated biological effects and signaling pathways. The HDL receptor, SR-BI, as well as the cell surface receptors for S1P (S1PRs) may be involved partially and/or completely in these HDL-induced processes. Here we investigate the nature of the HDL-stimulated interaction between the HDL receptor, SR-BI, and S1PR1 using a protein-fragment complementation assay and confocal microscopy. In both primary rat aortic vascular smooth muscle cells and HEK293 cells, the S1P content in HDL particles increased intracellular calcium concentration, which was mediated by S1PR1. Mechanistic studies performed in HEK293 cells showed that incubation of cells with HDL led to an increase in the physical interaction between the SR-BI and S1PR1 receptors that mainly occurred on the plasma membrane. Model recombinant HDL (rHDL) particles formed in vitro with S1P incorporated into the particle initiated the internalization of S1PR1, whereas rHDL without supplemented S1P did not, suggesting that S1P transported in HDL can selectively activate S1PR1. In conclusion, these data suggest that S1P in HDL stimulates the transient interaction between SR-BI and S1PRs that can activate S1PRs and induce an elevation in intracellular calcium concentration. PMID:27881715

Environmental 90Sr measurements

Science.gov (United States)

Paul, M.; Berkovits, D.; Cecil, L.D.; Feldstein, H.; Hershkowitz, A.; Kashiv, Y.; Vogt, S.

1997-01-01

90Sr (T1/2 = 28.5 years) is a long-lived radionuclide produced in nuclear fission. Fast radiochemical detection of 90Sr in environmental samples is not feasible using current analytical methods. Accelerator Mass Spectrometry (AMS) measurements of 90Sr were made with the Rehovot 14UD Pelletron accelerator at a terminal voltage of 11 or 12 MV using our standard detection system. Injection of hydride ions (SrH3-) was chosen owing to high beam intensity and low Coulomb explosion effects. 90Sr ions were identified and discriminated from isobaric 90Zr by measuring time of flight, total energy and three independent energy-loss signals in an ionization chamber. A reference sample and a ground-water sample were successfully measured. The detection limit determined for a laboratory blank by the residual counts in the 90Sr region is 90Sr/Sr = 3 ?? 10-13, corresponding in practice to (2-4) ?? 10790Sr atoms or about 0.5-1 pCi/L in environmental water samples.

Uptake and activity concentration of 137Cs and 90Sr in Salix viminalis

International Nuclear Information System (INIS)

Rosen, K.; Fircks, Y. von; Sennerby-Forsse, L.

1999-01-01

In order to gain a better understanding of the uptake, internal distribution of 137 Cs and 90 Sr and the effects of K-fertilisation of uptake of 137 Cs in Salix plantations, a K-fertilisation experiment including 137 Cs, 90 Sr and 40 K was performed. Previous studies with K-fertilization in Sweden have mainly dealt with the flow of 137 Cs between soil to plant in annual crops. The aim of this study was study the transfer of 137 Cs, 90 Sr and 40 K from soil to plants and to test the following hypothesis: that accumulation of 137 Cs and 90 Sr differs between plant organs, that there is a seasonal variation in uptake and concentration of 137 Cs and 90 Sr and that the availability of K is related to the uptake of 137 Cs. (au)

Maxdose-SR and popdose-SR routine release atmospheric dose models used at SRS

Energy Technology Data Exchange (ETDEWEB)

Jannik, G. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Trimor, P. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-07-28

MAXDOSE-SR and POPDOSE-SR are used to calculate dose to the offsite Reference Person and to the surrounding Savannah River Site (SRS) population respectively following routine releases of atmospheric radioactivity. These models are currently accessed through the Dose Model Version 2014 graphical user interface (GUI). MAXDOSE-SR and POPDOSE-SR are personal computer (PC) versions of MAXIGASP and POPGASP, which both resided on the SRS IBM Mainframe. These two codes follow U.S. Nuclear Regulatory Commission (USNRC) Regulatory Guides 1.109 and 1.111 (1977a, 1977b). The basis for MAXDOSE-SR and POPDOSE-SR are USNRC developed codes XOQDOQ (Sagendorf et. al 1982) and GASPAR (Eckerman et. al 1980). Both of these codes have previously been verified for use at SRS (Simpkins 1999 and 2000). The revisions incorporated into MAXDOSE-SR and POPDOSE-SR Version 2014 (hereafter referred to as MAXDOSE-SR and POPDOSE-SR unless otherwise noted) were made per Computer Program Modification Tracker (CPMT) number Q-CMT-A-00016 (Appendix D). Version 2014 was verified for use at SRS in Dixon (2014).

Comparison of Effects of Separate and Combined Sugammadex and Lipid Emulsion Administration on Hemodynamic Parameters and Survival in a Rat Model of Verapamil Toxicity.

Science.gov (United States)

Tulgar, Serkan; Kose, Halil Cihan; Demir Piroglu, Isılay; Karakilic, Evvah; Ates, Nagihan Gozde; Demir, Ahmet; Gergerli, Ruken; Guven, Selin; Piroglu, Mustafa Devrim

2016-03-25

Toxicity of calcium channel blockers leads to high patient mortality and there is no effective antidote. The benefit of using 20% lipid emulsion and sugammadex has been reported. The present study measured the effect of sugammadex and 20% lipid emulsion on hemodynamics and survival in a rat model of verapamil toxicity. In this single-blinded randomized control study, rats were separated into 4 groups of 7 rats each: Sugammadex (S), Sugammadex plus 20% lipid emulsion (SL), 20% lipid emulsion (L), and control (C). Heart rates and mean arterial pressures were monitored and noted each minute until death. Average time to death was 21.0±9.57 minutes for group C, 35.57±10.61 minutes for group S, 37.14±16.6 minutes for group L and 49.86±27.56 minutes for group SL. Time to death was significantly longer in other groups than in the control group (psugammadex and lipid emulsion had a positive effect on survival in patients with calcium channel blocker toxicity. Sugammadex and intralipid increased survival in a rat model of verapamil toxicity. The combination of both drugs may decrease cardiotoxicity. Sugammadex alone or combined with 20% lipid emulsion reduce the need for inotropic agents. The mechanism requires clarification with larger studies.

A μSR study of the metamagnetic phase transition in the electron-transfer salt [FeCp2*][TCNQ

International Nuclear Information System (INIS)

Blundell, Stephen J.; Lancaster, Tom; Brooks, Michael L.; Pratt, Francis L.; Taliaferro, Michelle L.; Miller, Joel S.

2006-01-01

We have used muon-spin rotation (μSR) to study the metamagnetic transition in [FeCp 2 *][TCNQ] where Cp*=C 5 Me 5 and TCNQ is 7,7,8,8-tetracyano-p-quinodimethane. This electron-transfer salt contains parallel chains of alternating [FeCp 2 *] + cations and [TCNQ] - anions. Our zero-field μSR data show the 2.5K transition and show that a static, but disordered, internal field distribution develops below this. High-transverse-field μSR has also been used to study the metamagnetic transition and the data illustrate how the internal field distribution changes through this transition

Neodymium-doped Sr5(PO4)3F and Sr5(VO4)3F

International Nuclear Information System (INIS)

Corker, D.L.; Nicholls, J.; Loutts, G.B.

1995-01-01

Neodymium-doped Sr 5 (PO 4 ) 3 F [neodymium strontium fluoride phosphate, (Nd,Sr) 5 (PO 4 ) 3 F] and neodymium-doped Sr 5 (VO 4 ) 3 F [neodymium strontium fluoride vanadate, (Nd,Sr) 5 (VO 4 ) 3 F] crystallize in space group P6 3 /m and are isostructural with calcium fluorophosphate, Ca 5 (PO 4 ) 3 F. There are two different Sr sites in Sr 5 (XO 4 ) 3 F, denoted Sr(1) and Sr(2). Using single-crystal X-ray diffraction the two structures were refined to R factors of 2.3 and 2.2%, respectively, showing that Nd is present at both Sr sites in (Sr,Nd) 5 (VO 4 ) 3 F but only at the Sr(2) site in (Sr,Nd) 5 (PO 4 ) 3 F. (orig.)

Is the Modern Marine 87Sr/86Sr Cycle Balanced?

Science.gov (United States)

Peucker-Ehrenbrink, B.

2017-12-01

The marine 87Sr/86Sr record is one of the best-reconstructed isotope records with thousands of high quality measurements spanning the past 800 million years. It records a global signal of tectonic, biotic and climatic processes on Earth. Yet despite decades of research we still do not know whether the current marine Sr budget is in steady state. Studies of the marine 88Sr/86Sr record indicate that sources and sinks do not balance. The magnitude and isotope composition of the terrestrial inputs are being debated, and the magnitude and temporal variability of unradiogenic contributions are not well constrained. Here I provide a revised assessment of all continental sources of Sr to the ocean, including river runoff, submarine groundwater discharge (Beck et al., 2013), dissolution of riverine suspended matter in seawater and dissolution of volcanic ash deposited on the ocean (Jones et al., 2012). I contrast continental sources of Sr with estimates of marine sources of Sr to seawater, specifically high- and low-temperature submarine hydrothermal fluids, as well as diffusive diagenetic fluxes. Best current data imply that unradiogenic submarine hydrothermal inputs to seawater are insufficient to balance the flux of radiogenic continental Sr. The revised assessment of riverine contributions is based on Sr data for almost 230 rivers, an increasing amount of time-series data for such rivers, as well as river discharge and sediment flux data for more than 2000 rivers. Regional sampling biases have been corrected with the aid of digital bedrock maps, specifically along the western margin of North America, East Africa and the large drainage region of Arabia, India and SE Asia. Significant uncertainty in the chemical and isotopic compositions of runoff from Greenland and East Africa remains. The main uncertainty in the budget, however, is related to the possibility that modern rivers do not represent the pre-anthropogenic (natural) state of continental runoff (e.g. Ganges

FEP report for the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

Skagius, Kristina [Kemakta Konsult AB, Stockholm (Sweden)

2006-11-15

This report documents the analysis and processing of features, events and processes, FEPs, that has been carried out within the safety assessment SR-Can, and forms an important part of the reporting of the project. The SR-Can project is a preparatory stage for the SR-Site assessment, and the report from that project will be used in support of SKB's application to build a final repository. The overall objective of the FEP analysis and processing included development of a database of features, events and processes, an SKB FEP database, in a format that facilitates both a systematic analysis of FEPs and documentation of that FEP analysis, as well as facilitating revisions and updates to be made in connection with new safety assessments. The overall objective also extended to the development of procedures for such a systematic FEP analysis as well as the application of those procedures in order to establish an SR-Can FEP catalogue within the framework of the SKB FEP database. The work started by implementing the content of the SR 97 Process Report into a database format suitable for import and processing of FEP information from other sources. The SR 97 version of the database was systematically audited against the NEA database with Project FEPs, version 1.2. In addition, an earlier audit of the SR 97 process report against the interaction matrices developed for a deep repository of the KBS-3 type was revisited and updated. Relevant FEPs identified through the audit process were sorted into three main categories i) FEPs related to the initial states of the repository system, ii) FEPs related to internal processes of the repository system, and iii) FEPs related to external impacts on the repository system. This resulted in additions to the SR 97 list of processes and to the lists of initial state FEPs and external factors to be addressed in further processing. The further processing of the initial state FEPs revealed that those FEPs that are not covered by the

Experimental autoabsorption curve 90Sr in SrCO3. Efficiency calculation to detection of 90Sr, 90Y and 90Sr + 90Y in a beta gas proportional counter

International Nuclear Information System (INIS)

Gasco, C.; Alvarez, A.

1987-01-01

Strontium-90 has been determined by radiochemical separation techniques in environmental samples. These techniques, of course, cannot separate the two strontium radionuclides from each other of from stable strontium. Consequently the end product of the chemical separation contains all strontium isotopes in SrCO 3 . The beta particules emitted by 90 Sr are absorbed by the SrCO 3 precipitate. This is the main source of error in the activity measurement. It has been prepared sources of 90 Sr in SrCO 3 in order to determinate the counting efficiency and autoabsorption curve. Also detection efficiencies have been calibrated using known activities of 90 Y and equilibrium mixture of 90 Sr+ 90 Y in the same geometry than our samples. The activity of 90 Sr by ingrowth of 90 Y has been calculated by our computer program. (author). 2 figs., 3 refs

Isotope ratio 87Sr/86Sr in limestones from Bambui group, Brazil (MG)

International Nuclear Information System (INIS)

Kawashita, K.; Mizusaki, A.M.P.; Kiang, C.H.

1987-01-01

The Sr composition of ancient seawater can be estimated from the analysis of carbonate rocks and, in some cases, used to estimate the age of the analyzed carbonate. The normalized 87Sr/86Sr ratios in calcium carbonate fractions from 14 core samples in the Bambui Group near Montalvania, MG, were found to range between .7077 and .7280. The higher values are attributable to Sr isotopic exchange between silicate and carbonate phases during diagenesis. The ratio of .7077 obtained in two pure calcium carbonate samples is here suggested as the best aproximation for the 87Sr/86Sr value for the Bambui sea. This ratio is compatible with an age of about 700 Ma., estimated from the published 87Sr/86Sr curve of Veizer and others, an age in accordance with Quadros recent (1987, in preparation) identification of marine acritarchs from the latest Precambrian (Vendian). (author) [pt

Structural and compositional characterization of synthetic (Ca,Sr)-tremolite and (Ca,Sr)-diopside solid solutions

Science.gov (United States)

Gottschalk, M.; Najorka, J.; Andrut, M.

Tremolite (CaxSr1-x)2Mg5[Si8O22/(OH)2] and diopside (CaxSr1-x)Mg[Si2O6] solid solutions have been synthesized hydrothermally in equilibrium with a 1 molar (Ca,Sr)Cl2 aqueous solution at 750°C and 200 MPa. The solid run products have been investigated by optical, electron scanning and high resolution transmission electron microscopy, electron microprobe, X-ray-powder diffraction and Fourier-transform infrared spectroscopy. The synthesized (Ca,Sr)-tremolites are up to 2000 µm long and 30 µm wide, the (Ca,Sr)-diopsides are up to 150 µm long and 20 µm wide. In most runs the tremolites and diopsides are well ordered and chain multiplicity faults are rare. Nearly pure Sr-tremolite (tr0.02Sr-tr0.98) and Sr-diopside (di0.01Sr-di0.99) have been synthesized. A continuous solid solution series, i.e. complete substitution of Sr2+ for Ca2+ on M4-sites exists for (Ca,Sr)-tremolite. Total substitution of Sr2+ for Ca2+ on M2-sites can be assumed for (Ca,Sr)-diopsides. For (Ca,Sr)-tremolites the lattice parameters a, b and β are linear functions of composition and increase with Sr-content whereas c is constant. For the diopside series all 4 lattice parameters are a linear function of composition; a, b, c increase and β decreases with rising Sr-content. The unit cell volume for tremolite increases 3.47% from 906.68 Å3 for tremolite to 938.21 Å3 for Sr-tremolite. For diopside the unit cell volume increases 4.87 % from 439.91 Å3 for diopside to 461.30 Å3 for Sr-diopside. The observed splitting of the OH stretching band in tremolite is caused by different configurations of the next nearest neighbors (multi mode behavior). Resolved single bands can be attributed to the following configurations on the M4-sites: SrSr, SrCa, CaCa and CaMg. The peak positions of these 4 absorption bands are a linear function of composition. They are shifted to lower wavenumbers with increasing Sr-content. No absorption band due to the SrMg configuration on the M4-site is observed. This indicates

Observation of field-induced long-range order in disordered Sr14Cu24O41

International Nuclear Information System (INIS)

Ohsugi, S.; Matsumoto, S.; Kitaoka, Y.; Matsuda, M.; Uehara, M.; Nagata, T.; Akimitsu, J.

2004-01-01

Field-induced magnetic order in a structural disordered single-crystal Sr 14 Cu 24 O 41 (Sr 14 -B) has been observed in the Cu-nuclear magnetic resonance (NMR) measurements for the ladder sites below 20 K under the magnetic field H∼11 T. For the Zhang Rice (ZR) sites in the chains, the spectrum splits below 20 K due to an appearance of the internal field, whereas that of less disordered Sr 14 -A does not. This gives an evidence of three-dimensional (3D) long-range (LR) ordering in Sr 14 -B below T N ∼20 K under H∼11 T

Lack of association of the HMGA1 IVS5-13insC variant with type 2 diabetes in an ethnically diverse hypertensive case control cohort

Directory of Open Access Journals (Sweden)

Karnes Jason H

2013-01-01

Full Text Available Abstract Background Recently, the high-mobility group A1 gene (HMGA1 variant IVS5-13insC has been associated with type 2 diabetes, but reported associations are inconsistent and data are lacking in Hispanic and African American populations. We sought to investigate the HMGA1-diabetes association and to characterize IVS5-13insC allele frequencies and linkage disequilibrium (LD in 3,070 Caucasian, Hispanic, and African American patients from the INternational VErapamil SR-Trandolapril STudy (INVEST. Methods INVEST was a randomized, multicenter trial comparing two antihypertensive treatment strategies in an ethnically diverse cohort of hypertensive, coronary artery disease patients. Controls, who were diabetes-free throughout the study, and type 2 diabetes cases, either prevalent or incident, were genotyped for IVS5-13insC using Taqman®, confirmed with Pyrosequencing and Sanger sequencing. For LD analysis, genotyping for eight additional HMGA1 single nucleotide polymorphisms (SNPs was performed using the Illumina® HumanCVD BeadChip. We used logistic regression to test association of the HMGA1 IVS5-13insC and diabetes, adjusted for age, gender, body mass index, and percentage European, African, and Native American ancestry. Results We observed IVS5-13insC minor allele frequencies consistent with previous literature in Caucasians and African Americans (0.03 in cases and 0.04 in controls for both race/ethnic groups, and higher frequencies in Hispanics (0.07 in cases and 0.07 in controls. The IVS5-13insC was not associated with type 2 diabetes overall (odds ratio 0.98 [0.76-1.26], p=0.88 or in any race/ethnic group. Pairwise LD (r2 of IVS5-13insC and rs9394200, a SNP previously used as a tag SNP for IVS5-13insC, was low (r2=0.47 in Caucasians, r2=0.25 in Hispanics, and r2=0.06 in African Americans. Furthermore, in silico analysis suggested a lack of functional consequences for the IVS5-13insC variant. Conclusions Our results suggest that IVS5-13ins

Multidrug reverting activity toward leukemia cells in a group of new verapamil analogues with low cardiovascular activity

DEFF Research Database (Denmark)

Biscardi, Monica; Teodori, Elisabetta; Caporale, Roberto

2005-01-01

36, CTS 27 and CTS 41, that are the most interesting compounds as MDR inhibitors, followed this course: MM 36>CTS 27>CTS 41, the last one presenting no cardiovascular activity. Chemosensivity to IDA in K-562/doxR cells and AML blasts could be enhanced in vitro by the adjuvant use of the six new VRP...... of these proteins, several attempts have been made to modulate their expression and activity (protein kinase C inhibitors, anti-MDR-1 oligonucleotides, pharmacological competitors and transcriptional inhibitors). Six new compounds (MM 36, CTS 4, CTS 9, CTS 12, CTS 27 and CTS 41), derived from verapamil (VRP), were......), in the presence or absence of inhibitors, showed that these compounds function well. All the resistance modifying agents potentiated IDA activity inducing a significant reduction (P

Reconstruction of the relative dynamics of 90Sr intake for the residents of the Techa river settlements

International Nuclear Information System (INIS)

Krivoschapov, Victor A.; Zalyapin, Vladimir I.

2002-01-01

Radioactive releases from the Mayak plutonium production complex (Souther Urals, Russia) during 1949-1956 into the Techa river resulted in chronic external and internal exposure of about 30,000 residents of riverside communities. Strontium-90 made a significant contribution in doses of internal exposure. The calculation of the internal exposure dose and the dynamics of 90 Sr intake is an important problem. The obtained solution qualitatively correctly reflects the dynamics of 90 Sr intake and is in agreement with available experimental data - substitution of the solution into initial integral relation showed the consistency between calculated and observed values

The role of Sr2+ on the structure and reactivity of SrO-CaO-ZnO-SiO2 ionomer glasses.

Science.gov (United States)

Boyd, Daniel; Towler, Mark R; Watts, Sally; Hill, Robert G; Wren, Anthony W; Clarkin, Owen M

2008-02-01

The suitability of Glass Polyalkenoate Cements (GPCs) for use in orthopaedics is retarded by the presence in the glass phase of aluminium, a neurotoxin. Unfortunately, the aluminium ion plays an integral role in the setting process of GPCs and its absence is likely to hinder cement formation. However, the authors have previously shown that aluminium free GPCs may be formulated based on calcium zinc silicate glasses and these novel materials exhibit significant potential as hard tissue biomaterials. To further improve their potential, and given that Strontium (Sr) based drugs have had success in the treatment of osteoporosis, the authors have substituted Calcium (Ca) with Sr in the glass phase of a series of aluminium free GPCs. However to date little data exists on the effect SrO has on the structure and reactivity of SrO-CaO-ZnO-SiO(2) glasses. The objective of this work was to characterise the effect of the Ca/Sr substitution on the structure of such glasses, and evaluate the subsequent reactivity of these glasses with an aqueous solution of Polyacrylic acid (PAA). To this end (29)Si MAS-NMR, differential scanning calorimetry (DSC), X-ray diffraction, and network connectivity calculations, were used to characterize the structure of four strontium calcium zinc silicate glasses. Following glass characterization, GPCs were produced from each glass using a 40 wt% solution of PAA (powder:liquid = 2:1.5). The working times and setting times of the GPCs were recorded as per International standard ISO9917. The results acquired as part of this research indicate that the substitution of Ca for Sr in the glasses examined did not appear to significantly affect the structure of the glasses investigated. However it was noted that increasing the amount of Ca substituted for Sr did result in a concomitant increase in setting times, a feature that may be attributable to the higher basicity of SrO over CaO.

Effect of Wood Aging on Wine Mineral Composition and 87Sr/86Sr Isotopic Ratio.

Science.gov (United States)

Kaya, Ayse D; Bruno de Sousa, Raúl; Curvelo-Garcia, António S; Ricardo-da-Silva, Jorge M; Catarino, Sofia

2017-06-14

The evolution of mineral composition and wine strontium isotopic ratio 87 Sr/ 86 Sr (Sr IR) during wood aging were investigated. A red wine was aged in stainless steel tanks with French oak staves (Quercus sessiliflora Salisb.), with three industrial scale replicates. Sampling was carried out after 30, 60, and 90 days of aging, and the wines were evaluated in terms of general analysis, phenolic composition, total polysaccharides, multielement composition, and Sr IR. Li, Be, Mg, Al, Sc, Ti, V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Mo, Sb, Cs, Ba, Pr, Nd, Sm, Eu, Dy, Ho, Er, Yb, Lu, Tl, and Pb elements and 87 Sr/ 86 Sr were determined by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) and Na, K, Ca, and Fe by flame atomic absorption spectrometry (FAAS). Two-way ANOVA was applied to assess wood aging and time effect on Sr IR and mineral composition. Wood aging resulted in significantly higher concentrations of Mg, V, Co, Ni, and Sr. At the end of the aging period, wine exhibited statistically identical Sr IR compared to control. Study suggests that wood aging does not affect 87 Sr/ 86 Sr, not precluding the use of this parameter for wine traceability purposes.

87Rb-87Sr chronology of H chondrites: constraint and speculations on the early evolution of their parent body

International Nuclear Information System (INIS)

Minster, J.-F.; Allegre, C.J.

1979-01-01

A precise 87 Rb- 87 Sr whole-rock isochron for H chrondrites and an internal isochron for Tieschitz (H3) have been determined. The age and 87 Sr/ 86 Sr initial ratio of the whole rocks are 4.25 +- 0.05 b.y. and 0.69876 +- 0.00040 (lambda( 87 Rb) = 1.42 X 10 -11 yr -1 ). For Tieschitz, whereas handipicked separates plot on a well-defined line, heavy liquid separates scatter in the 87 Rb/ 86 Sr vs. 87 Sr/ 86 Sr diagram. Leaching experiments by heavy liquids indicate that they might have a sizeable effect on Tieschitz minerals. The age and 87 Sr/ 86 Sr initial ratio as determined by handpicked separates are 4.53 +- 0.06 b.y. and 0.69880 +- 0.00020, indistinguishable from the whole-rock isochron. These results are interpreted as 'primitive isochrons' dating the condensation of chondrites from the solar nebula. The best value of this event is given by joining both isochrons together at 4.518 +- 0.026 b.y. and 87 Sr/ 86 Sr = 0.69881 +- 0.00016. The near identity of this initial ratio with the one of Allende white inclusions argues in favor of a sharp isochronism of condensation from a 87 Sr/ 86 Sr homogeneous nebula. Data from Guarena and Richardton are interpreted as secondary internal isochrons, 100 m.y. after the condensation of the whole rocks. The data are then used to constrain a thermal evolution model of the H chondrite parent body. This body might have a 150-175 km radius, and might have been heated by 26 Al. An 26 Al/ 27 Al ratio of 4-6 X 10 -6 is enough for heating such a body. Further tests for this model are proposed. (Auth.)

Endothelin receptor antagonists influence cardiovascular morphology in uremic rats.

Science.gov (United States)

Nabokov, A V; Amann, K; Wessels, S; Münter, K; Wagner, J; Ritz, E

1999-02-01

In is generally held that renal failure results in blood pressure (BP)-independent structural changes of the myocardium and the vasculature. The contribution, if any, of endothelin (ET) to these changes has been unknown. We morphometrically studied random samples of the left ventricle myocardium and small intramyocardial arteries in subtotally (5/6) nephrectomized (SNx) male Sprague-Dawley rats treated with either the selective ETA receptor antagonist BMS182874 (30 mg/kg/day) or the nonselective ETA/ETB receptor antagonist Ro46-2005 (30 mg/kg/day) in comparison with either sham-operated rats, untreated SNx, or SNx rats treated with the angiotensin-converting enzyme inhibitor trandolapril (0.1 mg/kg/day). Eight weeks later, systolic BP was lower in trandolapril-treated SNx compared with untreated SNx animals. No decrease in BP was seen following either ET receptor antagonist at the dose used. A significantly increased volume density of the myocardial interstitium was found in untreated SNx rats as compared with sham-operated controls. Such interstitial expansion was prevented by trandolapril and either ET receptor antagonist. SNx caused a substantial increase in the wall thickness of small intramyocardial arteries. The increase was prevented by trandolapril or BMS182874 treatment. The arteriolar wall:lumen ratio was significantly lower in all treated groups when compared with untreated SNx. In contrast, only trandolapril, but not the ET receptor antagonists, attenuated thickening of the aortic media in SNx animals. The ETA-selective and ETA/ETB-nonselective receptor antagonists appear to prevent development of myocardial fibrosis and structural changes of small intramyocardial arteries in experimental chronic renal failure. This effect is independent of systemic BP.

Photoluminescent properties of Sr2CeO4: Eu3+ and Sr2CeO4: Eu2+ phosphors suitable for near ultraviolet excitation

International Nuclear Information System (INIS)

Suresh, K.; Poornachandra Rao, N.V.; Murthy, K.V.R.

2014-01-01

Powder phosphors of 1 mol% Eu 3+ - and Eu 2+ -doped strontium cerium oxide (Sr 2 CeO 4 ) were synthesized by standard solid-state reaction method. Eu 3+ - and Eu 2+ -doped Sr 2 CeO 4 phosphors fired at 1100 ℃ for 2 h were analysed by X-ray diffraction (XRD) and photoluminescence (PL) techniques. The XRD patterns confirm that the obtained phosphors are a single phase of Sr 2 CeO 4 composed of orthorhombic structure. Room temperature PL excitation spectrum of air-heated Sr 2 CeO 4 : Eu phosphor has exhibited bands at 260, 280 and 350 nm. Whereas the excitation spectrum of Sr 2 CeO 4 : Eu phosphor heated under reducing (carbon) atmosphere exhibited single broadband range from 260 to 390 nm. The (PL) emission peaks of both the phosphors at 467 (blue), 537 (green) and 616 nm (red) generate white light under 260, 280 and 350 nm excitation wavelengths. The Commission International de l'Eclairage (CIE) colour coordinates conforms that these phosphors emitting white light. The results reveal that these phosphors are multifunctional phosphors which emit white light under these excitations that they could be used as white components for display and lamp devices and as well as possible good light-conversion phosphor LEDs under near-ultraviolet (nUV) chip. (author)

Geochronological synthesis of Bahia state and the crustal evolution, based in evolution diagram of Sr and initial rate of Sr87/Sr86

International Nuclear Information System (INIS)

Sato, K.

1986-01-01

The crustal evolution of the ancient terrains of the State of Bahia, Brazil, is attempted with the aid of Sr isotopic results as natural tracers. Some Nd and Pb isotopic data are also available, and support the main conclusions based on Sr evolution diagrams. The analysis of the Sr evolution diagrams shows that the Archean Terrains are mainly formed by accretion from mantle-derived material, but crustal reworking is indicated by the high initial 87 Sr/ 86 Sr value of the Jequie Complex. The Transamazonian mobile belt include both types of materials, but the 87 Sr/ 86 Sr value, generally lower than those of the Jequie Complex, markes improbable a direct derivation. During Middle and Late Proterozoic, the continental crust was already well consolidated, and reworking of crustal material predominated within the Espinhaco and Brasiliano folded systems [pt

Existence of the uranyl ion at regular Sr site in U doped SrBPO5

International Nuclear Information System (INIS)

Mithlesh Kumar; Mohapatra, M.; Natarajan, V.

2014-01-01

Actinide doped alkaline earth borophosphates of the general formula MBPO 5 (M = Ca 2+ , Sr 2+ , Ba 2+ ) are of special interest due to array of defect centers that can be generated in these compounds by internal (α and γ) irradiation effects. Further, the crystalline alkaline earth borophosphates are also reported to be isostructural with stillwellite-LnBSiO 5 , which are built up by BO 4 and SiO 4 tetrahedra. This structure suggests that the host MBPO 5 should be a good matrix for luminescence investigations for suitable activator ions. The important advantages of MBPO 5 type systems are their high luminescence, moderate preparation temperature and low thermal degradation. XRD pattern of the prepared phosphor confirmed the formation of SrBPO 5 in a single phase. The presence of uranium in SrBPO 5 sample was ascertained from Energy Dispersive X-ray Fluorescence (EDXRF) measurements performed on a Jordan Valley instrument. The U content in the sample was found to be about 0.85%. An Inductively Coupled Plasma Atomic Emission Spectrometric (ICP-AES), Jobin Yvon, France was used for analysis of the sample, which showed all other metallic impurities except U to be present at concentrations below 5 :U, PL, TSL and ESR studies were conducted on the solid state route samples. PL and TSL techniques were used with a view to understand the species responsible for the luminescence and its site symmetry

Comments on geochemical aspects of SR 97

International Nuclear Information System (INIS)

Arthur, R.C.; Wei Zhou

2000-01-01

copper shell may stabilize corrosion products (e.g., siderite, pyrite, Cu sulfides) that are not presently considered in SKBs models. The effects on the hydrochemical evolution of the canister resulting from the progressive concentration of solutions as H 2 O is consumed by corrosion of the iron insert is also not considered in SKBs models. The assumption in these models that iron corrodes in contact with water vapor is also questionable. Experimental evidence cited in support of this assumption suggests that in fact a condensation step is first required. If so, then a condensation mechanism [e.g., capillary condensation], under relevant thermal conditions expected in the near field, should be proposed and backed up with experimental evidence. If not, then a credible mechanism for corrosion of the insert in the presence of gaseous H 2 O should be elucidated on the basis of experimental investigation. The internal consistency of the thermodynamic database used in SR 97 to estimate radioelement solubilities is not evaluated by SKB. The internal consistency may be poor, however, because selection of preferred values is made with little regard to requirements that must be met, or approximated as closely as possible, to ensure internal consistency. If the database is not internally consistent, then it is difficult to make any objective assessment of its reliability. The chemistry of the near field is relatively unimportant in SR 97 compared with other international performance assessments, where in particular solubility-limiting constraints on the source term are based on predictions of the long-term chemical evolution of buffer porewaters. The rationale for this latter approach is that the properties of bentonite-porewater systems are thought to be better characterized and more likely to be time invariant than corresponding properties of other engineered barrier components or the geosphere. SKB have apparently rejected this line of reasoning, and, if so, an explanation

Results of field studies on 90SR and stable SR soil-to-plant transfer

International Nuclear Information System (INIS)

Gerzabek, M.H.; Artner, C.; Horak, O.; Mueck, K.

1992-01-01

In 1987 and 1988 at 35 sites plants ready to harvest and the corresponding soils (0 - 20 cm) were collected for 90 Sr and stable strontium analyses. Sample preparation and measurement led to a detection limit of 0.008 Bq 90 Sr kg -1 . The 90 Sr-contamination of Austrian soils ranged from 396 to 1998 Bq m -2 . Known from literature the contribution of the Chernobyl fallout amounted to app. 25 % of the total contamination. Stable strontium contents of the soils were between 6 and 62.5 mg kg -1 . Bariumtriethanolamine extracted 17.7 to 62.3 % of the total stable Sr in soil. 90 Sr-concentrations in cereal grains ranged from 0.03 to 0.67 Bq kg -1 (fresh wight) for maize and barley, respectively. The values for other foodstuff were between 0.15 (white cabbage) and 0.91 Bq kg -1 (spinach). Stable strontium contents were between 0.079 mg kg -1 (maize) and 72.5 mg kg -1 (celery shoot). The following mean 90 Sr soil-to-plant transfer factors for cereal grains were obtained: 0.010 (maize), 0.097 (rye), 0.049 (wheat), 0.095 (barley). Transfer factors for straw were up to 50 times higher (maize). The transfer of 90 Sr into vegetables and potatoes reached the same order of magnitude compared to the cereals. In all cases soil-to-plant transfer of stable Sr was clearly lower up to 60 % of the respective values for 90 Sr. Thus natural stable strontium is less plant available than 90 Sr. The influence of soil parameters on the 90 Sr transfer into plants was examinated by correlation analyses. Increasing exchangeable calcium contents of the soils resulted in a significant reduction of Sr soil-to-barley straw transfer. (authors)

Rapid bioassay method for estimation of 90Sr in urine samples by liquid scintillation counting

International Nuclear Information System (INIS)

Wankhede, Sonal; Chaudhary, Seema; Sawant, Pramilla D.

2018-01-01

Radiostrontium (Sr) is a by-product of the nuclear fission of uranium and plutonium in nuclear reactors and is an important radionuclide in spent nuclear fuel and radioactive waste. Rapid bioassay methods are required for estimating Sr in urine following internal contamination. Decision regarding medical intervention, if any can be based upon the results of urinalysis. The present method used at Bioassay Laboratory, Trombay is by Solid Extraction Chromatography (SEC) technique. The Sr separated from urine sample is precipitated as SrCO 3 and analyzed gravimetrically. However, gravimetric procedure is time consuming and therefore, in the present study, feasibility of Liquid Scintillation Counting for direct detection of radiostrontium in effluent was explored. The results obtained in the present study were compared with those obtained using gravimetric method

Effect of Sr/Ti Ratio on the Photocatalytic Properties of SrTiO3

International Nuclear Information System (INIS)

Sulaeman, U; Yin, S; Sato, T

2011-01-01

Since strontium titanate is a wide gap semiconductor, it requires UV light to generate the photocatalytic activities. Modification of strontium titanate to show photocatalytic activity under visible light irradiation is the essential work to efficiently utilize the sun light energy for environmental application. It is expected that the synthesis of SrTiO 3 with variation of Sr/Ti atomic ratio could induce the defect crystals having unique photocatalytic properties. The SrTiO 3 with various Sr/Ti atomic ratios were synthesized by microwave-assisted solvothermal reaction of SrCl 2 .6H 2 O and Ti(OC 3 H 7 ) 4 in KOH aqueous solutions with different atomic ratios of Sr/Ti. The products were characterized by TG-DTA, XRD and DRS. The photocatalytic activity was determined by DeNO x ability using LED lamps with the wavelengths of 627 nm (red), 530 nm (green), 445 nm (blue) and 390 nm (UV). The nanoparticles of perovskite type SrTiO 3 with the particle size of 30-40 nm were successfully synthesized. The visible light responsive photocatalytic activity was generated by adding excess amount of Sr. The photocatalytic activity in visible light could be enhanced by an increase in the Sr/Ti atomic ratio up to 1.25, indicating that the visible light responsive photocatalytic activity is due to the generation of new band gap between the conduction band and valence band of SrTiO 3 by the formation of oxygen vacancy.

Intrinsic defects and spectral characteristics of SrZrO3 perovskite

Science.gov (United States)

Li, Zhenzhang; Duan, He; Jin, Yahong; Zhang, Shaoan; Lv, Yang; Xu, Qinfang; Hu, Yihua

2018-04-01

First-principles calculations and experiment analysis were performed to study the internal relation between seven types of intrinsic defects and the persistent luminescence in SrZrO3 host material. The calculation shows that rich zirconium defects have the low energy cost and thus are easy to form. Zr vacancies are too high energy to play any role in defect which is related luminescence phenomenon of SrZrO3 phosphor. However, oxygen vacancies stand out as a likely candidate, because it can yield two carrier reservoirs: a fully-occupied singlet electron's reservoir which lies above the valence band maximum, and an empty triply degenerate hole's reservoir which is just below the conduction band minimum. Sr vacancies are not directly relevant to the persistent luminescence due to its too shallow electron trap level. The characteristics of these defects are fully explained by the equilibrium properties of SrZrO3. An experimental study of the thermoluminescence glow for these defects is conducted and the calculation is consistent with the experimental results. A mechanism of the persistent luminescence for SrZrO3:Pr3+, Eu3+ is explained according to oxygen vacancies trap center. Findings of this study may serve as theoretical references for controlling intrinsic traps by more refined experiments.

Regional and interspecific variation in Sr, Ca, and Sr/Ca ratios in avian eggshells from the USA.

Science.gov (United States)

Mora, Miguel A; Brattin, Bryan; Baxter, Catherine; Rivers, James W

2011-08-01

To examine regional variation in strontium (Sr), which at high concentrations may reduce eggshell quality, increase egg breakage and reproductive failure, we analyzed Sr, and calcium (Ca) concentrations and Sr/Ca ratios in eggshells from 20 avian species from California, Texas, Idaho, Kansas, and Michigan. In addition, we included data previously reported from Arizona to expand the regional comparisons and to better establish patterns of Sr, and Sr/Ca ratios in bird species across the United States. We found Sr concentrations varied significantly among regions, among species, and among foraging guilds; this variability is strongly influenced by the Sr/Ca ratios in surface water from locations close to the region where the eggshells were collected. Sr concentrations and Sr/Ca ratios were significantly higher in bird eggshells from the Volta wildlife region in the San Joaquin Valley, California and in various locales from Arizona. Sr concentrations and Sr/Ca ratios in bird eggshells from other locations in the USA were lower than those detected in these two regions. Among foraging guilds, invertivores had the highest Sr concentrations and Sr/Ca ratios and carnivores had the lowest. In general, the Sr/Ca ratio increased strongly with increasing Sr concentrations (R(2) = 0.99, P eggshells suggesting that these values could be determined from Sr/Ca ratios in water. Eggshell thickness was poorly correlated with Sr (R(2) = 0.03) but had a significant and positive correlation with Ca and was more properly correlated by a quadratic equation (R(2) = 0.50, Thickness = 2.13 - 0.02Ca - 3.07 * 10(-5)Ca(2)). Our study provides further evidence that Sr accumulates significantly in the avian eggshell, in some regions at concentrations which could be of concern for potential negative effects on reproduction. We suggest that when assessing the effects of metals on avian reproduction in regions with high Sr deposits in rock and soil, Sr concentrations in the eggshell also should be

K-Ca and Rb-Sr Dating of Lunar Granite 14321 Revisited

Science.gov (United States)

Simon, Justin I.; Shih, C.-Y.; Nyquist, L. E.

2011-01-01

K-Ca and Rb-Sr age determinations were made for a bulk feldspar-rich portion of an Apollo rock fragment of the pristine lunar granite clast (14321,1062), an acid-leached split of the sample, and the leachate. K-Ca and Rb-Sr data were also obtained for a whole rock sample of Apollo ferroan anorthosite (FAN, 15415). The recent detection [1] of widespread intermediate composition plagioclase indicates that the generation of a diversity of evolved lunar magmas maybe more common and therefore more important to our understanding of crust formation than previously believed. Our new data strengthen the K-Ca and Rb-Sr internal isochrons of the well-studied Apollo sample 14321 [2], which along with a renewed effort to study evolved lunar magmas will provide an improved understanding of the petrogenetic history of evolved rocks on the Moon.

Level of 90Sr in the urine of a small group of Finnish people

International Nuclear Information System (INIS)

Puhakainen, M.; Suomela, M.; Rahola, T.

1999-01-01

The aim of the study was to test the feasibility of the applied analysis method for 90 Sr and if possible to estimate the current level of the 90 Sr concentration in the urine. Urine samples were collected from seven Finnish volunteers in connection with studies of 137 Cs body burdens. The activity measurements of urine samples were performed 14 - 18 days after chemical separation of 90 Sr to allow ingrowing of 90 Y. The 90 Sr and 90 Y activities were measured simultaneously using a Quantulus liquid scintillation spectrometer. The detection limit for 90 Sr was 0.0033 Bq per sample, or 0.0007-0.0015 Bq 1 -1 . The 90 Sr activities in urine varied between 0.006 and 0.046 Bq 1 1 . The daily urinary excretion was found to be 0.007-0.018 Bq for the five volunteers that collected three-day urine samples. Assuming that the daily 90 Sr intake was constant and that 18% of the ingested activity was excreted in urine, the mean intake in the investigated group would vary between 0.039 and 0.1 Bq d -1 . Based on these estimated intake values the respective annual effective internal doses from 90 Sr and 90 Y varied from 0.4 to 1 Sv during the sampling period. (au)

Facile Synthesis of SrCO3-Sr(OH2/PPy Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

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Alfredo Márquez-Herrera

2016-01-01

Full Text Available Pyrrole monomer was chemically polymerized onto SrCO3-Sr(OH2 powders to obtain SrCO3-Sr(OH2/polypyrrole nanocomposite to be used as a candidate for photocatalytic degradation of methylene blue dye (MB. The material was characterized by Fourier transform infrared (FTIR spectroscopy, UV/Vis spectroscopy, and X-ray diffraction (XRD. It was observed from transmission electronic microscopy (TEM analysis that the reported synthesis route allows the production of SrCO3-Sr(OH2 nanoparticles with particle size below 100 nm which were embedded within a semiconducting polypyrrole matrix (PPy. The SrCO3-Sr(OH2 and SrCO3-Sr(OH2/PPy nanocomposites were tested in the photodegradation of MB dye under visible light irradiation. Also, the effects of MB dye initial concentration and the catalyst load on photodegradation efficiency were studied and discussed. Under the same conditions, the efficiency of photodegradation of MB employing the SrCO3-Sr(OH2/PPy nanocomposite increases as compared with that obtained employing the SrCO3-Sr(OH2 nanocomposite.

High pressure {mu}SR studies: rare earths and related materials

Energy Technology Data Exchange (ETDEWEB)

Kalvius, G.M., E-mail: kalvius@ph.tum.de; Schreier, E. [Technical University Munich, Physics Department (Germany)], E-mail: kalvius@ph.tum.de; Ekstroem, M.; Hartmann, O. [Uppsala University, Physics Department (Sweden); Henneberger, S., E-mail: kalvius@ph.tum.de; Kratzer, A. [Technical University Munich, Physics Department (Germany)], E-mail: kalvius@ph.tum.de; Waeppling, R. [Uppsala University, Physics Department (Sweden); Martin, E., E-mail: kalvius@ph.tum.de; Burghart, F.J. [Technical University Munich, Physics Department (Germany)], E-mail: kalvius@ph.tum.de; Ballou, R.; Deportes, J. [CNRS, Laboratoire Louis Neel (France); Niedermayer, Ch. [University of Constance, Faculty of Physics (Germany)

2000-11-15

After a short introduction to {mu}SR with respect to the study of magnetic properties, followed by a brief outline of the principle of the high pressure-low temperature {mu}SR spectrometer installed at the Paul Scherrer Institute, we discuss some measurements on rare earth materials employing this instrument. They are concerned with: (1) The pressure dependence of the spin turning process in ferromagnetic Gd. (2) The volume dependence of the internal magnetic field in the heavy rare earth metals Gd, Dy, and Ho in their ordered magnetic states. (3) The response of the (first order) magnetic transition in the frustrated antiferromagnets of type RMn{sub 2} (R = Y,Gd) to pressure. (4) The variation of magnetic parameters with pressure in La{sub 2}CuO{sub 4} (powder sample), the antiferromagnetic parent compound of the high T{sub C} superconductors of type La{sub 2-x}(Sr, Ba){sub x}CuO{sub 4}. In conclusion a short outlook on further developments is given.

Coral Sr-U Thermometry

Science.gov (United States)

DeCarlo, T. M.; Gaetani, G. A.; Cohen, A. L.; Foster, G. L.; Alpert, A.; Stewart, J.

2016-12-01

Coral skeletons archive the past two millennia of climate variability in the oceans with unrivaled temporal resolution. However, extracting accurate temperature information from coral skeletons is confounded by "vital effects", which often override the temperature dependence of geochemical proxies. Here, we present a new approach to coral paleothermometry based on results of abiogenic precipitation experiments interpreted within a framework provided by a quantitative model of the coral biomineralization process. We conducted laboratory experiments to test the temperature and carbonate chemistry controls on abiogenic partitioning of Sr/Ca and U/Ca between aragonite and seawater, and we modeled the sensitivity of skeletal composition to processes occurring at the site of calcification. The model predicts that temperature can be accurately reconstructed from coral skeleton by combining Sr/Ca and U/Ca ratios into a new proxy, Sr-U. We tested the model predictions with measured Sr/Ca and U/Ca ratios of fourteen Porites sp. corals collected from the tropical Pacific Ocean and the Red Sea, with a subset also analyzed using the boron isotope (δ11B) pH proxy. Observed relationships among Sr/Ca, U/Ca, and δ11B agree with model predictions, indicating that the model accounts for the key features of the coral biomineralization process. We calibrated Sr-U to instrumental temperature records and found that it captures 93% of mean annual variability (26-30 °C) and predicts temperature within 0.5 °C (1 σ). Conversely, Sr/Ca alone has an error of prediction of 1 °C and often diverges from observed temperature by 3 °C or more. Many of the problems afflicting Sr/Ca - including offsets among neighboring corals and decouplings from temperature during coral stress events - are reconciled by Sr-U. By accounting for the influence of the coral biomineralization process, the Sr-U thermometer may offer significantly improved reliability for reconstructing ocean temperatures from coral

Solar Thermochemical Energy Storage Through Carbonation Cycles of SrCO3/SrO Supported on SrZrO3.

Science.gov (United States)

Rhodes, Nathan R; Barde, Amey; Randhir, Kelvin; Li, Like; Hahn, David W; Mei, Renwei; Klausner, James F; AuYeung, Nick

2015-11-01

Solar thermochemical energy storage has enormous potential for enabling cost-effective concentrated solar power (CSP). A thermochemical storage system based on a SrO/SrCO3 carbonation cycle offers the ability to store and release high temperature (≈1200 °C) heat. The energy density of SrCO3/SrO systems supported by zirconia-based sintering inhibitors was investigated for 15 cycles of exothermic carbonation at 1150 °C followed by decomposition at 1235 °C. A sample with 40 wt % of SrO supported by yttria-stabilized zirconia (YSZ) shows good energy storage stability at 1450 MJ m(-3) over fifteen cycles at the same cycling temperatures. After further testing over 45 cycles, a decrease in energy storage capacity to 1260 MJ m(-3) is observed during the final cycle. The decrease is due to slowing carbonation kinetics, and the original value of energy density may be obtained by lengthening the carbonation steps. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

SR-can: preliminary feedback to canister fabrication, repository design and future R and D

International Nuclear Information System (INIS)

Hedin, A.; Sellin, P.

2007-01-01

This paper discusses preliminary feedback from SKB's on-going safety assessment SR-Can, to he finalized in 2006. The assessment, which is not part of a formal licence application, is an important step towards the SR-Site assessment to be delivered in 2008 and which will support a licence application for a Swedish deep repository for spent nuclear fuel. The SR-Can assessment will use data from the initial stage of the on-going site investigations at the two candidate sites at Forsmark and Oskarshamn. Review comments on SR-Can from Swedish authorities are expected in the summer of 2007 and these will be taken into account when preparing the SR-Site assessment. An Interim version of the SR-Can report was produced in September 2004 and has been reviewed by the Swedish authorities supported by an international review team. The assessment concerns a KBS 3 repository for which the key safety related features can be summarised in the primary safety function isolation and the secondary function retardation. The isolation function is more prominent in the KBS 3 method compared to many other repository concepts. (authors)

International cooperation

International Nuclear Information System (INIS)

1996-01-01

In 1995, Nuclear Regulatory Authority of the Slovak Republic (NRA SR) ensured foreign cooperation particularly in the frame of the Slovak Republic is membership in the IAEA, as well as cooperation with the Nuclear Energy Agency of the Organization for Economic Cooperation and Development (OECD NEA), cooperation with European Union in the frame of PHARE programmes, and intergovernmental cooperation and cooperation among nuclear regulatory authorities. With respect to an international importance, prestige and a wide-scope possibilities of a technical assistance , either a direct one (expert assessments, technology supplies, work placement, scientific trips, training courses) or indirect one (participation at various conferences, seminars, technical committees, etc), the most important cooperation with the IAEA in Vienna. In 1994, the Slovak Republic, was elected to the Board Governors, the represent the group of Eastern European countries. The Slovak Government entrusted the NRA SR's Chairman with representing the Slovak Republic in the Board of Governors. Owing to a good name of Slovakia was elected to the one of two Vice-Chairmen of the Board of Governors at the 882-nd session on the Board. IAEA approved and developed 8 national projects for Slovakia in 1995. Generally, IAEA is contracting scientific contracts with research institutes, nuclear power plants and other organizations. Slovak organizations used these contracts as complementary funding of their tasks. In 1995, there were 12 scientific contracts in progress, or approved respectively. Other international activities of the NRA SR, international co-operations as well as foreign affairs are reported

Results of study of Sr-90 and Cs-137 content in organism and effective doses of internal and external irradiation of Ukrainian population residing in different regions

International Nuclear Information System (INIS)

Kalmykov, L.; Gur, E.

1996-01-01

The authors have studied effective doses of internal and external radiation for 1992-1994 in the residents of Chernigov and Kharkov Regions of Ukraine, i.e. those who live in the zone of strict radioecologic control and in relatively ''clean'' zones, respectively. In 95% of the investigated residents of Chernigov Region Cs-137 activity in the organism was lower than 1500 Bq, maximum amount being 11 kBq. Conditioned Cs-137 effective dose of internal radiation did not exceed 250 micro Sv per year, in 96% of the investigated subjects it was less than 30 micro Sv per year. Mean amount of this radionuclide in the organisms of both adults and children aged 3-6 years residing in Kharkov Region was 90 and 6 Bq respectively, dose being 2 and 0.4 micro Sv per year. Sr-90 amount in the bone tissue decreases with the age and for the residents of Chernigov region it was 7-23 Bq/kg of bone, for the adult residents of Kharkov region it was about 3 Bq/kg of bone. Mean effective dose of internal radiation due to Sr-90 incorporation for the residents of both Kharkov and Chernigov Regions was 0.7 and 1.9 micro Sv per year. Effective dose of external radiation for the residents of Kharkov Region has not changed since the Chernobyl accident. Total effective dose of external and internal radiation in various professional groups for the residents of Chernigov region increased by 80 micro Sv per year which makes up 14% of mean population dose in Ukraine. (author). 11 refs, 5 tabs

CHARACTERIZATION OF THE PARTIALLY PURIFIED PLANTARCIN SR18 PRODUCED BY LACTOBACILLUS PLANTARUM SR18

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Wagih El-Shouny

2013-04-01

Full Text Available The bacteriocin bound to the cells and that secreted into the culture filtrate of Lactobacillus plantarum SR18 were precipitated by 75% ammomium sulphate, dialysed and further purified by Gel filtration on Sephadex G-100. Bacteriocins were purified from proteins bound to the cell of L. plantarum SR18 (plantarcin SR18 a and culture filtrate proteins (plantarcin SR18 b, respectively. The SDS-PAGE of partially purified Plantarcin SR18a showed a molecular weight of 3.5 KDa. While, plantarcin SR18 b had a molecular weight of 10.3 KDa. The antibacterial activity of the tested plantarcin SR18 preparations suffered no measurable loss after 45 min at 80ºC. Whereas, At 100ºC, significant decrease in the activity of bacteriocin preparations (60- 80 % took place by the end of 45 min. At pH ranged from 5-8, the activity of the plantarcin SR18 preparations suffered no measurable loss. Dissociating agents significantly affected the bacteriocin activity. Thus, tween 80 and mercaptoethanol increased the activity of bacteriocin preparations to 1.2-1.4 fold. Sodium dodecyl sulphate (SDS increased the activity of the tested bacteriocin preparations by about 20%.The lowest residual activity (60% was recorded after treatment with Triton X100 for 45 min. Protease completely inhibited the activities of all forms of plantarcin SR18 after 45 min at 37ºC.

Estimate of the internal doses received by the population of Bucharest due to 137 Cs and 90 Sr intake in the first five years after the Chernobyl accident

International Nuclear Information System (INIS)

Toader, Maria; Vasilache, R. A.

1995-01-01

The evolution of the 137 Cs and 90 Sr daily intake between April 1986 and March 1991 as well as the internal doses resulting from ingestion of contaminated food is presented for a group of adults living in Bucharest. The results indicate that the effective doses due to 137 Cs and 90 Sr dietary intake had the highest values in the first year after the Chernobyl accident, namely, 796 μSv as a result of 137 Cs dietary intake and 23 μSv as a result of the 90 Sr dietary intake. The effective doses committed annually due to the Caesium-137 dietary intake decreased very fast from 796 μSv committed in the first year after the accident to 7.3 μSv committed in the fifth year after the accident. Although the effective dose committed in the first year after the accident due to the Strontium-90 dietary intake was much smaller than the dose due to the Caesium-137 (23 μSv), the decrease was slower so that the effective dose committed in the fifth year after the accident due to the Strontium-90 dietary intake was 7.5 μSv. (authors)

Magnetism in the p-type Monolayer II-VI semiconductors SrS and SrSe

Science.gov (United States)

Lin, Heng-Fu; Lau, Woon-Ming; Zhao, Jijun

2017-01-01

Using density functional theory calculations, we study the electronic and magnetic properties of the p-type monolayer II-VI semiconductors SrX (X = S,Se). The pristine SrS and SrSe monolayers are large band gap semiconductor with a very flat band in the top valence band. Upon injecting hole uniformly, ferromagnetism emerges in those system in a large range of hole density. By varying hole density, the systems also show complicated phases transition among nonmagnetic semiconductor, half metal, magnetic semiconductor, and nonmagnetic metal. Furthermore, after introducing p-type dopants in SrS and SrSe via substitutionary inserting P (or As) dopants at the S (or Se) sites, local magnetic moments are formed around the substitutional sites. The local magnetic moments are stable with the ferromagnetic order with appreciable Curie temperature. The ferromagnetism originates from the instability of the electronic states in SrS and SrSe with the large density of states at the valence band edge, which demonstrates a useful strategy for realizing the ferromagnetism in the two dimensional semiconductors. PMID:28378761

Electronic parameters of Sr2M2O7 (M = V, Nb, Ta) and Sr-O chemical bonding

DEFF Research Database (Denmark)

Atuchin, Victor V.; Grivel, Jean-Claude; Zhang, Zhaoming

2010-01-01

XPS measurements were carried out on Sr2Nb2O7 and Sr2Ta2O7 powder samples, which were synthesized using standard solid state method. The binding energy differences between the O 1s and cation core level, Δ(O-Sr) = BE(O 1s) - BE(Sr 3d5/2), was used to characterize the valence electron transfer...... on the formation of the Sr-O bonds. The chemical bonding effects were considered on the basis of our XPS results for Sr2Nb2O7 and Sr2Ta2O7 and the previously published structural and XPS data for other Sr-oxide compounds. A new empirical relationship between Δ(O-Sr) and L(Sr-O) was obtained. Possible applications...

Rb-Sr systematics in drill core samples of the Eye-Dashwa Lakes pluton at the whole rock and mineral scale

International Nuclear Information System (INIS)

Peterman, Z.E.; Futa, K.; Kamineni, D.C.

1990-01-01

Twenty-one whole-rock samples from boreholes ATK-1 and ATK-6 define a precise Rb-Sr isochron with an age of 2637 ± 33 Ma and initial 87 Sr/ 86 Sr intercept, IR(Sr), of 0.70144 ± 0.00006. An internal mineral isochron for ATC-1 (991-997) and biotites from ATK-1 (35.63) and ATK-1 (3.84) give younger ages of 2541 ± 14 Ma 2574 ± 25 Ma, and 2534 ± 25 Ma, respectively. Data for samples from fracture zones scatter but correlate around an isochron of 2281 ± 153 Ma. The internal isochron and biotite ages record cooling below about 300 C due to uplift and erosion. The younger age, 2281 ± 153 Ma, records an episode or episodes of brittle failure at relatively high crustal levels. These fractures provided pathways for infiltration of water, which facilitated the mineralogical alteration

Li4SrCa(SiO4)2:Ce3+, a highly efficient near-UV and blue emitting orthosilicate phosphor

International Nuclear Information System (INIS)

Zhang, Jilin; Zhang, Weilu; Qiu, Zhongxian; Zhou, Wenli; Yu, Liping; Li, Zhiqiang; Lian, Shixun

2015-01-01

High quantum efficiency is a vital parameter of phosphors for practical application. An efficient near-UV and blue emitting phosphor Li 4 SrCa(SiO 4 ) 2 :Ce 3+ was synthesized by a traditional solid-state reaction, and luminescent properties were studied in detail. The Ce 3+ -activated phosphor can emit both a near-UV light centred at 345 nm and a blue light peaking at 420 nm when Ce 3+ occupies the Sr and Ca site, respectively. The internal quantum efficiency (IQE) of Li 4 SrCa(SiO 4 ) 2 :0.03Ce 3+ is as high as 97% under the excitation at 288 nm, while the external quantum efficiency (EQE) is 66%. The IQE and EQE values of Li 4 SrCa(SiO 4 ) 2 :0.03Ce 3+ under the excitation at 360 nm are 82% and 31%, respectively. - Highlights: • Phosphor Li 4 SrCa(SiO 4 ) 2 :Ce 3+ emits a near-UV (345 nm) and a blue light (420 nm). • Emission band at 345 nm originates from Ce 3+ on Sr site. • Emission band at 420 nm belongs to Ce 3+ on Ca site. • Internal quantum efficiency is 97% for Li 4 SrCa(SiO 4 ) 2 :0.03Ce 3+ excited at 288 nm

Systematic variations of 87Sr/56Sr ratios, Sr compositions, selected major-oxide concentrations, and mineral abundances in piston cores from the Red Sea

International Nuclear Information System (INIS)

Boger, P.D.; Boger, J.L.; Faure, G.

1980-01-01

A mixing model is presented which relates the concentrations of Sr to the 87 Sr/ 86 Sr ratios and concentrations of other elements contained in a mixture of two components. The model is applied to the measured 87 Sr/ 86 Sr ratios, Sr, CaO, Fe 2 O 3 and SiO 2 concentrations of the detrital fractions of sediment from three piston cores representing different depositional environments in the Red Sea. The sediment is shown to be a mixture of two components derived from old sialic rocks and young volcanic rocks of the surrounding land masses. One of the cores contained a third component which is identified as authigenic Fe 2 O 3 . Removal of this contaminant is shown to return the system to its original detrital constituents. (Auth.)

Addition to the analysis of the Sr VI and Sr VII spectra

International Nuclear Information System (INIS)

Wyart, J.F.

1989-01-01

Fifty-six lines of multicharged strontium are measured with an improved wavelength accuracy, or interpreted for the first time. They are 4p-4s, 4p-5s and 4p-4d transitions in Sr VII and 4p-5s transitions in Sr VI. The revision of the singlet-triplet connection in Sr VII is supported by theoretical survey of the ground configuration in Ge-like ions. (orig.)

Function modification of SR-PSOX by point mutations of basic amino acids

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Chen Chunxia

2011-04-01

Full Text Available Abstract Background Atherosclerosis (AS is a common cardiovascular disease. Transformation of macrophages to form foam cells by internalizing modified low density-lipoprotein (LDL via scavenger receptor (SR is a key pathogenic process in the onset of AS. It has been demonstrated that SR-PSOX functions as either a scavenger receptor for uptake of atherogenic lipoproteins and bacteria or a membrane-anchored chemokine for adhesion of macrophages and T-cells to the endothelium. Therefore, SR-PSOX plays an important role in the development of AS. In this study the key basic amino acids in the chemokine domain of SR-PSOX have been identified for its functions. Results A cell model to study the functions of SR-PSOX was successfully established. Based on the cell model, a series of mutants of human SR-PSOX were constructed by replacing the single basic amino acid residue in the non-conservative region of the chemokine domain (arginine 62, arginine 78, histidine 80, arginine 82, histidine 85, lysine 105, lysine 119, histidine 123 with alanine (designated as R62A, R78A, H80A, R82A, H85A, K105A, K119A and H123A, respectively. Functional studies showed that the mutants with H80A, H85A, and K105A significantly increased the activities of oxLDL uptake and bacterial phagocytosis compared with the wild-type SR-PSOX. In addition, we have also found that mutagenesis of either of those amino acids strongly reduced the adhesive activity of SR-PSOX by using a highly non-overlapping set of basic amino acid residues. Conclusion Our study demonstrates that basic amino acid residues in the non-conservative region of the chemokine domain of SR-PSOX are critical for its functions. Mutation of H80, H85, and K105 is responsible for increasing SR-PSOX binding with oxLDL and bacteria. All the basic amino acids in this region are important in the cells adhesion via SR-PSOX. These findings suggest that mutagenesis of the basic amino acids in the chemokine domain of SR-PSOX may

Polymorphism in the Plasmodium falciparum chloroquine-resistance transporter protein links verapamil enhancement of chloroquine sensitivity with the clinical efficacy of amodiaquine

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Warhurst David C

2003-09-01

Full Text Available Abstract Background Chloroquine accumulates in the acidic digestive vacuole of the intraerythrocytic malaria parasite, and prevents the detoxication of haematin released during haemoglobin digestion. Changes in protein PfCRT in the digestive vacuole membrane of growing intra-erythrocytic stages of Plasmodium falciparum are crucial for resistance. Expressed in yeast, PfCRT resembles an anion channel. Depressed anion channel function could increase intralysosomal pH to reduce entry of basic drug, or enhanced function could reduce drug interaction with target haematin. The most important resistance-associated change is from positively-charged lysine-76 to neutral threonine which could facilitate drug efflux through a putative channel. It has been proposed that the resistance-reversing effect of verapamil is due to hydrophobic binding to the mutated PfCRT protein, and replacement of the lost positive charge, which repels the access of 4-aminoquinoline cations, thus partially restoring sensitivity. Desethylamodiaquine, the active metabolite of amodiaquine, which has significant activity in chloroquine-resistance, may also act similarly on its own. Methods Changes in physicochemical parameters in different CQ-resistant PfCRT sequences are analysed, and correlations with drug activity on lines transfected with different alleles of the pfcrt gene are examined. Results and conclusions The results support the idea that PfCRT is a channel which, in resistant parasites, can allow efflux of chloroquine from the digestive vacuole. Activity of the chloroquine/verapamil combination and of desethylamodiaquine both correlate with the mean hydrophobicity of PfCRT residues 72-76. This may partly explain clinical-resistance to amodiaquine found in the first chloroquine-resistant malaria cases from South America and enables tentative prediction of amodiaquine's clinical activity against novel haplotypes of PfCRT.

Evaluation of food contamination and health risks due to the radioactive fallout 90Sr before 2010

International Nuclear Information System (INIS)

Shimada, Yoko; Morisawa, Shinsuke

2013-01-01

Before the Fukushima Daiichi nuclear power plant accident, radionuclides like 90 Sr released by atmospheric nuclear detonation tests and the Chernobyl accident have been transported worldwide in the environment and finally taken up by humans through various pathways. In this research, the health risks caused by the prolonged exposure to fallout 90 Sr through food ingestion pathways were evaluated age-dependently for the reference Japanese since 1945 until 2010, using the mathematical model for evaluating global distribution of 90 Sr with food ingestion considering the domestic and international food supply in Japan. The model estimates were compared with the monitoring data of 90 Sr in Japanese total diet and 90 Sr concentration in food to examine the model validity. The results of this evaluation would be useful for understanding the background situations without the Fukushima accident and give important knowledge for the radiological health risk assessment of this accident. (author)

Strontium (Sr) separation from seawater using titanate adsorbents: Effects of seawater matrix ions on Sr sorption behavior

Science.gov (United States)

Ryu, Jungho; Hong, Hye-jin; Ryu, Taegong; Park, In-Su

2017-04-01

Strontium (Sr) which has many industrial applications such as ferrite magnet, ceramic, and fire works exists in seawater with the concentration of approximately 7 mg/L. In previous report estimating economic potential on recovery of various elements from seawater in terms of their commercial values and concentrations in seawater, Sr locates upper than approximate break-even line, which implies Sr recovery from seawater can be potentially profitable. Recently, Sr separation from seawater has received great attention in the environmental aspect after Fukushima Nuclear Power Plant (NPP) accident which released much amount of radioactive Sr and Cs. Accordingly, the efficient separation of radioactive elements released to seawater has become critical as an important technological need as well as their removal from radioactive wastes. So far, it has been introduced to separate Sr from aqueous media by various methods including solvent extraction, adsorption by solid materials, and ion exchange. Among them, the adsorption technique using solid adsorbents is of great interest for selectively separating Sr from seawater with respect to low concentration level of Sr. In this study, we synthesized titanate nanotube (TiNT) by simple hydrothermal reaction, characterized its physicochemical properties, and systematically evaluated Sr sorption behavior under various reaction conditions corresponding to seawater environment. The synthesized TiNT exhibited the fibril-type nanotube structure with high specific surface area of 260 m2/g. The adsorption of Sr on TiNT rapidly occurred following pseudo-second-order kinetic model, and was in good agreement with Langmuir isotherm model, indicating maximum adsorption capacity of 97 mg/g. Based on Sr uptake and Na release with stoichiometric balance, sorption mechanism of Sr on TiNT was found to be ion-exchange between Na in TiNT lattice and Sr in solution phase, which was also confirmed by XRD and Raman analysis. Among competitive ions, Ca

Input of 87Sr/86Sr ratios and Sr geochemical signatures to update knowledge on thermal and mineral waters flow paths in fractured rocks (N-Portugal)

International Nuclear Information System (INIS)

Marques, J.M.; Carreira, P.M.; Goff, F.; Eggenkamp, H.G.M.; Antunes da Silva, M.

2012-01-01

Strontium isotopes and other geochemical signatures are used to determine the relationships between CO 2 -rich thermal (Chaves: 76 °C) and mineral (Vilarelho da Raia, Vidago and Pedras Salgadas: 17 °C) waters discharging along one of the major NNE–SSW trending faults in the northern part of mainland Portugal. The regional geology consists of Hercynian granites (syn-tectonic-310 Ma and post-tectonic-290 Ma) intruding Silurian metasediments (quartzites, phyllites and carbonaceous slates). Thermal and mineral waters have 87 Sr/ 86 Sr isotopic ratios between 0.716713 and 0.728035. 87 Sr/ 86 Sr vs. 1/Sr define three end-members (Vilarelho da Raia/Chaves, Vidago and Pedras Salgadas thermal and mineral waters) trending from rainfall composition towards that of the CO 2 -rich thermal and mineral waters, indicating different underground flow paths. Local granitic rocks have 87 Sr/ 86 Sr ratios of 0.735697–0.789683. There is no indication that equilibrium was reached between the CO 2 -rich thermal and mineral waters and the granitic rocks. The mean 87 Sr/ 86 Sr ratio of the thermal and mineral waters (0.722419) is similar to the Sr isotopic ratios of the plagioclases of the granitic rocks (0.71261–0.72087). The spatial distribution of Sr isotope and geochemical signatures of waters and the host rocks suggests that the thermal and mineral waters circulate in similar but not the same hydrogeological system. Results from this study could be used to evaluate the applicability of this isotope approach in other hydrogeologic investigations.

A high 87Sr 86Sr mantle source for low alkali tholeiite, northern Great Basin

Science.gov (United States)

Mark, R.K.; Lee, Hu C.; Bowman, H.R.; Asaro, F.; McKee, E.H.; Coats, R.R.

1975-01-01

Olivine tholeiites, the youngest Tertiary units (about 8-11 m.y. old) at five widely spaced localities in northeastern Nevada, are geologically related to the basalts of the Snake River Plain, Idaho, to the north and are similar in major element and alkali chemistry to mid-ocean ridge basalts (MORB) and island arc tholeiites. The measured K (1250-3350 ppm), Rb (1??9-6??2 ppm) and Sr (140-240 ppm) concentrations overlap the range reported for MORB. Three of the five samples have low, unfractionated rare earth element (REE) patterns, the other two show moderate light-REE enrichment. Barium concentration is high and variable (100-780 ppm) and does not correlate with the other LIL elements. The rocks have 87Sr/86Sr = 0??7052-0??7076, considerably higher than MORB (~0??702-0??703). These samples are chemically distinct (i.e. less alkalic) from the olivine tholeiites from the adjacent Snake River Plain, but their Sr isotopic compositions are similar. They contain Sr that is distinctly more radiogenic than the basalts from the adjacent Great Basin. About 10 b.y. would be required for the mean measured Rb/Sr (~ 0??02) of these samples to generate, in a closed system, the radiogenic Sr they contain. The low alkali content of these basalts makes crustal contamination an unlikely mechanism. If the magma is uncontaminated, the time-averaged Rb/Sr of the source material must have been ~0??04. A significant decrease in Rb/Sr of the source material (a factor 2??) thus most probably occurred in the relatively recent (1??09 yr) past. Such a decrease of Rb/Sr in the mantle could accompany alkali depletion produced by an episode of partial melting and magma extraction. In contrast, low 87Sr 86Sr ratios indicate that the source material of the mid-ocean ridge basalts may have been depleted early in the Earth's history. ?? 1975.

SR 97. Processes in the repository evolution. Background report to SR 97

Energy Technology Data Exchange (ETDEWEB)

Hedin, A. [ed.

1999-11-01

This report describes, in a comprehensive and coherent fashion, all identified internal processes of importance for the post-closure evolution and safety of a KBS-3 repository for spent nuclear fuel. The report has been written to be used in the SR 97 project, which has limited the time available for its preparation. Differences in the level of detail in descriptions of different processes do not always reflect differences in the significance of the processes. Discussions of different types of uncertainties could in many cases be broadened and deepened, and the stylistic quality could sometimes be improved. Like other background material for the safety assessments, the process report is also expected to require revision as site-specific conditions are progressively clarified. Today's version of the process report is therefore the firstversion of a report that will be revised prior to every safety report. The intention is to perform the first revision of the report after scrutiny of SR 97. The report describes the internal processes which over time lead to changes in a KBS-3 repository for spent nuclear fuel. The context of the material in the report is described in SR 97 Main Report and briefly entails the following: The repository has been divided into four subsystems: fuel/cavity, cast iron insert/copper canister, buffer/backfill and geosphere. A number of processes of importance for the post-closure evolution of the repository have been identified within each subsystem. This has been done with the aid of material in the so-called interaction matrices previously developed by SKB. The processes have been divided into the categories thermal, hydraulic, mechanical and chemical. Furthermore, there are processes related to radiation and radionuclide transport. The identified processes are documented in this report. Each subsystem has its own chapter, and each chapter is divided into radiation related, thermal, hydraulic, mechanical and chemical processes as well

SR 97. Processes in the repository evolution. Background report to SR 97

International Nuclear Information System (INIS)

Hedin, A.

1999-11-01

This report describes, in a comprehensive and coherent fashion, all identified internal processes of importance for the post-closure evolution and safety of a KBS-3 repository for spent nuclear fuel. The report has been written to be used in the SR 97 project, which has limited the time available for its preparation. Differences in the level of detail in descriptions of different processes do not always reflect differences in the significance of the processes. Discussions of different types of uncertainties could in many cases be broadened and deepened, and the stylistic quality could sometimes be improved. Like other background material for the safety assessments, the process report is also expected to require revision as site-specific conditions are progressively clarified. Today's version of the process report is therefore the first version of a report that will be revised prior to every safety report. The intention is to perform the first revision of the report after scrutiny of SR 97. The report describes the internal processes which over time lead to changes in a KBS-3 repository for spent nuclear fuel. The context of the material in the report is described in SR 97 Main Report and briefly entails the following: The repository has been divided into four subsystems: fuel/cavity, cast iron insert/copper canister, buffer/backfill and geosphere. A number of processes of importance for the post-closure evolution of the repository have been identified within each subsystem. This has been done with the aid of material in the so-called interaction matrices previously developed by SKB. The processes have been divided into the categories thermal, hydraulic, mechanical and chemical. Furthermore, there are processes related to radiation and radionuclide transport. The identified processes are documented in this report. Each subsystem has its own chapter, and each chapter is divided into radiation related, thermal, hydraulic, mechanical and chemical processes as well as

SR 97. Processes in the repository evolution. Background report to SR 97

International Nuclear Information System (INIS)

Hedin, A.

1999-11-01

This report describes, in a comprehensive and coherent fashion, all identified internal processes of importance for the post-closure evolution and safety of a KBS-3 repository for spent nuclear fuel. The report has been written to be used in the SR 97 project, which has limited the time available for its preparation. Differences in the level of detail in descriptions of different processes do not always reflect differences in the significance of the processes. Discussions of different types of uncertainties could in many cases be broadened and deepened, and the stylistic quality could sometimes be improved. Like other background material for the safety assessments, the process report is also expected to require revision as site-specific conditions are progressively clarified. Today's version of the process report is therefore the first version of a report that will be revised prior to every safety report. The intention is to perform the first revision of the report after scrutiny of SR 97. The report describes the internal processes which over time lead to changes in a KBS-3 repository for spent nuclear fuel. The context of the material in the report is described in SR 97 Main Report and briefly entails the following: The repository has been divided into four subsystems: fuel/cavity, cast iron insert/copper canister, buffer/backfill and geosphere. A number of processes of importance for the post-closure evolution of the repository have been identified within each subsystem. This has been done with the aid of material in the so-called interaction matrices previously developed by SKB. The processes have been divided into the categories thermal, hydraulic, mechanical and chemical. Furthermore, there are processes related to radiation and radionuclide transport. The identified processes are documented in this report. Each subsystem has its own chapter, and each chapter is divided into radiation related, thermal, hydraulic, mechanical and chemical processes as well as

87Sr/86Sr isotope fingerprinting of Scottish and Icelandic migratory shorebirds

International Nuclear Information System (INIS)

Evans, Jane; Bullman, Rhys

2009-01-01

Biosphere Sr isotope composition data from Iceland and Scotland suggest that terrestrially feeding birds from these two countries will have significantly different 87 Sr/ 86 Sr isotope composition in their tissues. The aim of this study is to test if these differences can be measured within the bone and feather of migratory wading birds, who feed terrestrially as juveniles, thus providing a provenance tool for these birds. The study shows that birds can be distinguished on the basis of the Sr isotope composition of their bone. The field for Icelandic birds is defined by data from juvenile common redshank (Tringa totanus) and whimbrel (Numenius phaeopus) which give 0.7056 ± 0.0012, (2σ, n = 7). The majority of Scottish birds in this study are from coastal regions and have a signature close to that of seawater of 0.7095 ± 0.0006 (2σ, n = 9). The Sr ratios in the body tissue of these two populations of all Icelandic and Scottish adult and juvenile birds analysed are significantly different (p 87 Sr/ 86 Sr values as high as 0.7194 which reflect their non-marine diet. Icelandic redshank (Tringa totanus robusta) that have flown to Scotland and returned to Iceland show the effect of the Scottish contribution to their diet with elevated values of 0.7086 ± 0.0004, (2σ, n = 6). Redshank found in Scotland that cannot be classified on the basis biometric analysis are shown to be of Icelandic origin and analysis of the primary feathers from two birds demonstrates that isotope variation between feathers could be used to track changes in diet related to the timing of individual feather growth.

Transport of Sr 2+ and SrEDTA 2- in partially-saturated and heterogeneous sediments

Science.gov (United States)

Pace, M. N.; Mayes, M. A.; Jardine, P. M.; McKay, L. D.; Yin, X. L.; Mehlhorn, T. L.; Liu, Q.; Gürleyük, H.

2007-05-01

Strontium-90 has migrated deep into the unsaturated subsurface beneath leaking storage tanks in the Waste Management Areas (WMA) at the U.S. Department of Energy's (DOE) Hanford Reservation. Faster than expected transport of contaminants in the vadose zone is typically attributed to either physical hydrologic processes such as development of preferential flow pathways, or to geochemical processes such as the formation of stable, anionic complexes with organic chelates, e.g., ethylenediaminetetraacetic acid (EDTA). The goal of this paper is to determine whether hydrological processes in the Hanford sediments can influence the geochemistry of the system and hence control transport of Sr 2+ and SrEDTA 2-. The study used batch isotherms, saturated packed column experiments, and an unsaturated transport experiment in an undisturbed core. Isotherms and repacked column experiments suggested that the SrEDTA 2- complex was unstable in the presence of Hanford sediments, resulting in dissociation and transport of Sr 2+ as a divalent cation. A decrease in sorption with increasing solid:solution ratio for Sr 2+ and SrEDTA 2- suggested mineral dissolution resulted in competition for sorption sites and the formation of stable aqueous complexes. This was confirmed by detection of MgEDTA 2-, MnEDTA 2-, PbEDTA 2-, and unidentified Sr and Ca complexes. Displacement of Sr 2+ through a partially-saturated undisturbed core resulted in less retardation and more irreversible sorption than was observed in the saturated repacked columns, and model results suggested a significant reservoir (49%) of immobile water was present during transport through the heterogeneous layered sediments. The undisturbed core was subsequently disassembled along distinct bedding planes and subjected to sequential extractions. Strontium was unequally distributed between carbonates (49%), ion exchange sites (37%), and the oxide (14%) fraction. An inverse relationship between mass wetness and Sr suggested that

EXAFS and EPR study of La0.6Sr0.2Ca0.2MnO3 and La0.6Sr0.2Ba0.2MnO3

International Nuclear Information System (INIS)

Yang, D.-K.Dong-Seok; Ulyanov, A.N.; Phan, Manh-Huong; Kim, Ikgyun; Ahn, Byong-Keun; Rhee, Jang Roh; Kim, Jung Sun; Nguyen, Chau; Yu, Seong-Cho

2003-01-01

Extended X-ray absorption fine structure (EXAFS) analysis and electron-paramagnetic resonance (EPR) have been used to examine the local structure and the internal dynamics of La 0.6 Sr 0.2 Ca 0.2 MnO 3 and La 0.6 Sr 0.2 Ba 0.2 MnO 3 lanthanum manganites. The Mn-O bond distance (∼1.94 Angst for both samples) and the Debye-Waller factors (0.36x10 -2 and 0.41x10 -2 Angst 2 for La 0.6 Sr 0.2 Ca 0.2 MnO 3 and for La 0.6 Sr 0.2 Ba 0.2 MnO 3 , respectively) were obtained from the EXAFS analysis. The dependence of the EPR line width on dopant kind (Ca or Ba) showed a decrease of the spin-lattice interaction with an increase of the Curie temperature. For both compositions, the EPR line intensity followed the exponential law I(T)=I 0 exp(E a /k B T), deduced on the basis of the adiabatic polaron hopping model

Dielectric enhancement of BaTiO3/SrTiO3 superlattices with embedded Ni nanocrystals

International Nuclear Information System (INIS)

Xiong Zhengwei; Sun Weiguo; Wang Xuemin; Jiang Fan; Wu Weidong

2012-01-01

Highlights: ► The BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs were successfully fabricated by L-MBE. ► The influence with the various concentrations of Ni nanocrystals embedded in BaTiO 3 /SrTiO 3 superlattices was also discussed. ► The BaTiO 3 /SrTiO 3 superlattices with lower concentration of embedded Ni NCs had higher permittivity and dielectric loss compared with the pure BaTiO 3 /SrTiO 3 superlattices. ► The dielectric enhancement of BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs was proposed to explained by Drude quasi-free-electron theory. - Abstract: The self-organized Ni nanocrystals (NCs) were embedded in BaTiO 3 /SrTiO 3 superlattices using laser molecular beam epitaxy (L-MBE). The stress of the composite films was increased with the increasing concentration of embedded Ni NCs, as investigation in stress calculation. The influence with the various concentrations of Ni NCs embedded in BaTiO 3 /SrTiO 3 superlattices was also discussed. The internal stress of the films was too strong to epitaxial growth of BaTiO 3 /SrTiO 3 superlattices. Compared with the pure BaTiO 3 /SrTiO 3 superlattices, the BaTiO 3 /SrTiO 3 superlattices with lower concentration of embedded Ni NCs had higher permittivity and dielectric loss. Furthermore, the dielectric enhancement of BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs was proposed to explained by Drude quasi-free-electron theory.

The transfer of 137Cs and 90Sr from feed to rabbits

International Nuclear Information System (INIS)

Semioshkina, N.; Proehl, G.; Savinkov, A.; Voigt, G.

2007-01-01

Radiological assessment of the impact of nuclear weapons testing on the local population in the Semipalatinsk Test Site (STS) requires comprehensive site-specific information on radionuclide behaviour in the environment. However, information on radionuclide behaviour in the conditions of the STS is rather sparse and, in particular, there are no data in the literature on parameters of radionuclide transfer from feed to rabbit products which have been identified as contributors to internal dose to the inhabitants. The transfer of 137 Cs and 90 Sr to rabbit meat was studied under laboratory conditions in a controlled experiment with 32 locally bred rabbits maintained in the Kazakh Agricultural Research Institute. The equilibrium transfer coefficients for 137 Cs and 90 Sr from feed to rabbit meat were estimated to be 0.4 d kg -1 and 0.15 d kg -1 , respectively. The biological half-lives were estimated to be 0.1 d for 137 Cs and 0.14 d for 90 Sr. Whereas for 137 Cs the distribution in the body is relatively homogeneous, there are large differences between the organs and tissues for 90 Sr for which, as expected, the highest concentrations were found in bone

International Peer Review of Swedish Nuclear Fuel and Waste Management Company's SR-Can interim report

International Nuclear Information System (INIS)

Sagar, Budhi; Bailey, Lucy; Bennett, David G.; Egan, Mike; Roehlig, Klaus

2004-12-01

SKB has produced an interim safety assessment report as part of its work to develop a licence application for the construction of a spent nuclear fuel encapsulation plant. The purpose of the interim report is to set out and demonstrate SKB's proposed methodology for long-term safety assessment. The aim of producing an interim report is to allow the Swedish regulatory authorities (SKI and SSI) to review and comment on SKB's proposed methodology before it is used in support of a formal licence application. To help inform their review of SKB's proposed methodology, the authorities appointed an international review team (IRT) to carry out a review of SKB's interim safety assessment report. Comments from the IRT are presented in this document and will be considered by the regulatory authorities in developing their own view of SKB's proposed methodology. The IRT's review included examination of SKB's documentation (the 'Interim Main Report of the Safety Assessment SR-Can' and four supporting documents) and hearings with SKB staff and contractors. The hearings provided an opportunity for the IRT to discuss the SR-Can safety assessment with the authors and contributors to SKB's work. As directed by SKI and SSI, the IRT's review focused on methodological aspects and sought to determine whether SKB's proposed safety assessment methodology: (i) is fit for the purpose of supporting a licence application; (ii) has a reasonable prospect of leading to a safety assessment that is sufficiently comprehensive, reproducible, traceable and transparent; (iii) is compatible with the authorities' regulations and guidance. No evaluation of long term safety or site acceptability was attempted by the IRT. At the request of SKI and SSI, the IRT's review considered and made recommendations on the following issues: Description of the initial state of the repository and its components; Description of features, events and processes (FEPs) relevant to repository evolution; Strategy for safety

Measurements of Sr/Ca in bones to evaluate differences in temperature

International Nuclear Information System (INIS)

Santos, P.R.; Added, N.; Aburaya, J.H.; Rizzutto, M.A.

2008-01-01

Analysis of aragonite from sea shells and coral skeletons showed a clear correlation between the strontium and calcium concentrations for these crystals (Sr/Ca ratio) and seawater temperature obtained by satellites and ship readings. In this work we present the results of a study that correlates Sr/Ca ratio with formation temperature of another calcium crystal, the hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ), main mineral compound of teeth and bones from vertebrates. These animals, independent of its thermoregulation pattern (endothermic or ectothermic) have variations of internal temperature along the body. One interesting application of this work is to differentiate warm-blooded animals from cold-blooded ones just by measuring Sr/Ca ratio in their bones. Bones from a crocodile from Caiman yacare species and two dogs, a poodle and a non defined race, were analyzed using PIXE technique and thick target correction. A 1.78 (18) MeV external proton beam was used in LAMFI-USP with an accumulated charge of about 10 μC for probing the samples. Emitted X-rays were collected using Si-PIN detectors (140 keV for Fe). As in coral skeletons, the Sr/Ca ratio of animals is lower in the body's warmer parts and higher in colder parts

Measurements of Sr/Ca in bones to evaluate differences in temperature

Energy Technology Data Exchange (ETDEWEB)

Santos, P.R. [IFUSP, Travessa R da rua do Matao 187, Cidade Universitaria, CEP 05508-970, Sao Paulo, SP (Brazil); Added, N. [IFUSP, Travessa R da rua do Matao 187, Cidade Universitaria, CEP 05508-970, Sao Paulo, SP (Brazil)], E-mail: nemitala@dfn.if.usp.br; Aburaya, J.H.; Rizzutto, M.A. [IFUSP, Travessa R da rua do Matao 187, Cidade Universitaria, CEP 05508-970, Sao Paulo, SP (Brazil)

2008-04-15

Analysis of aragonite from sea shells and coral skeletons showed a clear correlation between the strontium and calcium concentrations for these crystals (Sr/Ca ratio) and seawater temperature obtained by satellites and ship readings. In this work we present the results of a study that correlates Sr/Ca ratio with formation temperature of another calcium crystal, the hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}), main mineral compound of teeth and bones from vertebrates. These animals, independent of its thermoregulation pattern (endothermic or ectothermic) have variations of internal temperature along the body. One interesting application of this work is to differentiate warm-blooded animals from cold-blooded ones just by measuring Sr/Ca ratio in their bones. Bones from a crocodile from Caiman yacare species and two dogs, a poodle and a non defined race, were analyzed using PIXE technique and thick target correction. A 1.78 (18) MeV external proton beam was used in LAMFI-USP with an accumulated charge of about 10 {mu}C for probing the samples. Emitted X-rays were collected using Si-PIN detectors (140 keV for Fe). As in coral skeletons, the Sr/Ca ratio of animals is lower in the body's warmer parts and higher in colder parts.

Thermodynamic assessment of the Pb-Sr system

Directory of Open Access Journals (Sweden)

Zhang H.

2017-01-01

Full Text Available The Pb-Sr system has been critically reviewed and modeled by means of the CALPHAD (CALculation of PHAse Diagrams approach. It contains seven stoichiometric compounds, i.e. SrPb3, Sr3Pb5, Sr2Pb3, SrPb, Sr5Pb4, Sr5Pb3 and Sr2Pb, in which the SrPb3 and Sr2Pb phases melt congruently, and the other five phases form via peritectic reactions. The enthalpies of formation for the intermetallic compounds at 0 K are provided by first-principles calculations. The liquid, fcc and bcc phases are modeled as substitutional solution phases. Both Redlich-Kister and exponential polynomials are used to describe the excess Gibbs energy of the liquid. Two sets of self-consistent thermodynamic parameters are obtained by considering reliable experimental data and the computed enthalpies of formation. Comprehensive comparisons between the calculated and measured phase diagram and thermodynamic data show that the experimental information is satisfactorily accounted for by the present thermodynamic description.

System of Sr(NO2)2-Sr(OH)2-H2O at 25 deg C

International Nuclear Information System (INIS)

Popova, T.B.; Berdyukova, V.A.; Khutsistova, F.M.

1990-01-01

Sr(NO 2 ) 2 -Sr(OH) 2 -H 2 O system was investigated by the methods of solubility, density, viscosity, electric conductivity and refractometry. It was established that its compoments form the compound 4Sr(NO 2 ) 2 xSr(OH) 2 x8H 2 O. The compound was separated from solution; its density, decomposition temperature were determined; IR spectra and X-ray patterns of prepared and initial compounds were obtained

C, Sr and Sr isotopic composition on probable vendian- tommotian carbonate sequences in Nw Argentina

International Nuclear Information System (INIS)

Sial, A. N.; Ferreira, V.P; Toselli, A.J.; Acenolaza, F.G; Pimentel, M.M; Parada, M.A; Alonso, R.N

2001-01-01

C-isotope stratigraphy is one of the most powerfool tools in Precambrian chronostratigraphy, especially when sediments lack recognizable animal fossils. The δ 13 C secular variation curves for marine carbonates in the Neoproterozoic-Cambrian interval show strong positive-negative excursions, several of them interpreted as the stratigraphic position of ancient ice ages (Hoffman et al. 1998). The Sr isotope composition of the seawater for this age interval is characterized by a continuous increase of 87 Sr/ 86 Sr that is interrupted, several times, by sharp rises, which represent important changes in the Earth history (Montanez et al. 2000). Only limited data on the behavior of C and Sr isotopes in carbonates are available in South America. We examine here carbonate sequences from the Argentine Precordillera, San Juan province, and from other carbonate sequences in NW Argentina that could be, potentially, proxies for the Precambrian-Cambrian transition. We have studied their δ 13 C and 87 Sr/ 86 Sr chemostratigraphy and compare it to global C and Sr isotope secular variation curves for this time span. This study aims to improve the relatively coarse stratigraphic resolution provided only by the study of the fossil record in some of the carbonate successions under consideration (au)

Measurement of resonance integral of the 90Sr(n,γ)91Sr reaction

International Nuclear Information System (INIS)

Nakamura, Shoji; Furutaka, Kazuyoshi; Wada, Hiroaki; Katoh, Toshio; Harada, Hideo; Fujii, Toshiyuki; Yamana, Hajimu

2001-01-01

To obtain fundamental data for research on nuclear transmutation method of radioactive wastes, the resonance integral (I 0 ) of the 90 Sr(n,γ) 91 Sr reaction was measured with an activation method. (author)

Effect of the internal pressure and the anti-site disorder on the structure and magnetic properties of ALaFeTiO6 (A=Ca, Sr, Ba) double perovskite oxides

International Nuclear Information System (INIS)

Elbadawi, A.A.; Yassin, O.A.; Gismelseed, Abbasher A.

2013-01-01

Successful preparation of double perovskite oxides of chemical formula ALaFeTiO 6 (A=Ba, Sr and Ca) has been achieved by following the precursor method. The samples were studied by means of X-ray diffraction and Mössbauer spectroscopy. The Rietveld analysis of the X-ray diffraction data showed that all the samples have anti-site disorder. The presence of anti-site disorder has altered the electronic environment around the Fe ion sites which creates electric field gradient between two different sites. Observation of quadruple splitting in the ideal cubic perovskite BaLaFeTiO 6 (its tolerance factor equals 1) is the evidence of this anti-site generated electric field gradient. The valence state of the Fe atom determined from the measurements of the Mössbauer effect of 57 Fe at room temperature and 80 K showed that the iron ion has the Fe 3+ high spin state as extracted from the values of the isomer shift for all the samples. It is evidenced that the anti-site disorder has no appreciable effect on the spin state of the Fe ion, but alters the charge densities at the Fe sites and influences the hyperfine parameters of the present samples. Weak ferromagnetism is observed in CaLaFeTiO 6 and SrLaFeTiO 6 and is related to both the internal pressure and the anti-site effect which facilitate the occurrence of the Fe 3+ ↑−O−Fe 3+ ↓ antiferromagnetic interaction with canted spin. - Highlights: ► Anti-site disorder was revealed in (Ca,Sr,Ba)LaFeTiO 6 double perovskites. ► Mössbauer spectroscopy revealed a dependence of the quadruple splitting and the cation size mismatch. ► Weak ferromagnetism is evidenced due to internal pressure and anti-site disorder.

Thermal infrared and microwave absorbing properties of SrTiO3/SrFe12O19/polyaniline nanocomposites

International Nuclear Information System (INIS)

Hosseini, Seyed Hossein; Zamani, Parisa; Mousavi, S.Y.

2015-01-01

Graphical abstract: We have developed a new perspective of applications and properties of conducting polymers. The combination of absorption ability prepared nanocomposites in the present of PANI display a great potential in organization of shielding structures into thermal IR and microwave. Further investigations using other conducting polymers to demonstrate their capability for advance thermal IR and microwave shielding devices is under way. The application of these samples may improve the IR thermographic detection, catalysis, sensors, magnetic data storage, electromagnetic resonance wave absorption, photonic crystals, and microelectronic devices and military aspects. - Highlights: • The SrTiO 3 /SrFe 12 O 19 /PANI exhibited electric and electromagnetic properties. • The SrTiO 3 /SrFe 12 O 19 /PANI has shielding structures into thermal IR and microwave. • Increasing weight ratios and thicknesses will increase thermal IR ability. • Increasing weight ratios and thicknesses will increase microwave absorption ability. - Abstract: Polyaniline (PANI) as a unique polymer that also has electromagnetic absorption used as the substrate. In this research, SrTiO 3 was synthesized as IR absorbent and core and then SrFe 12 O 19 as microwave absorbent was prepared on SrTiO 3 via co-precipitation method as the first shell. As the next step, PANI was coated on SrTiO 3 /SrFe 12 O 19 nanoparticles via in situ polymerization by multi core–shell structures (SrTiO 3 /SrFe 12 O 19 /PANI). Nanometer size and structures of samples were measured by TEM, XRD and FTIR. Morphology of nanocomposite was showed by SEM images. The magnetic and electric properties were also performed by VSM and four probe techniques. Thermal infrared (IR) absorption and microwave reflection loss of nanocomposites were investigated at 10–40 μm and 8–12 GHz, IR and microwave frequencies, respectively. The results showed that the SrTiO 3 /SrFe 12 O 19 /PANI nanocomposites have good compatible

Changes in local surface structure and Sr depletion in Fe-implanted SrTiO{sub 3} (001)

Energy Technology Data Exchange (ETDEWEB)

Lobacheva, O., E-mail: olobache@gmail.com [Department of Physics and Astronomy, Western University, London, ON N6A 5B7 (Canada); Yiu, Y.M. [Department of Chemistry, Western University, London, ON N6A 5B7 (Canada); Chen, N. [Canadian Light Source, Saskatoon, SK S7N 0X4 (Canada); Sham, T.K.; Goncharova, L.V. [Department of Physics and Astronomy, Western University, London, ON N6A 5B7 (Canada); Department of Chemistry, Western University, London, ON N6A 5B7 (Canada)

2017-01-30

Highlights: • Fe ion implantation of SrTiO{sub 3} and post-implantation results in formation of Sr{sub 1-y}Ti{sub 1-x}Fe{sub x+y}O{sub 3-δ} phase. • In Sr{sub 1-y}Ti{sub 1-x}Fe{sub x+y}O{sub 3-δ} phase, Fe assumes Fe{sup 3+} oxidation state in the bulk and Fe{sup 2+} oxidation state in the near surface area. • FEFF9 calculations indicate that Fe ions can substitute both Ti and Sr sites. • Formation of Sr{sub 1-y}Ti{sub 1-x}Fe{sub x+y}O{sub 3-δ} phase is accompanied by Sr depletion in the near surface region. - Abstract: Local surface structure of single crystal strontium titanate SrTiO{sub 3} (001) samples implanted with Fe in the range of concentrations between 2 × 10{sup 14} to 2 × 10{sup 16} Fe/cm{sup 2} at 30 keV has been investigated. In order to facilitate Fe substitution (doping), implanted samples were annealed in oxygen at 350 °C. Sr depletion was observed from the near-surface layers impacted by the ion-implantation process, as revealed by Rutherford Backscattering Spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), X-ray Absorption Near Edge Spectroscopy (XANES), and Atomic Force Microscopy (AFM). Hydrocarbon contaminations on the surface may contribute to the mechanisms of Sr depletion, which have important implications for Sr(Ti{sub 1-x}Fe{sub x})O{sub 3-δ} materials in gas sensing applications.

New aragonite 87Sr/86Sr records of Mesozoic ammonoids and approach to the problem of N, O, C and Sr isotope cycles in the evolution of the Earth

Science.gov (United States)

Zakharov, Yuri D.; Dril, Sergei I.; Shigeta, Yasunari; Popov, Alexander M.; Baraboshkin, Eugenij Y.; Michailova, Irina A.; Safronov, Peter P.

2018-02-01

New Sr isotope data from well-preserved aragonite ammonoid shell material from the Mesozoic are compared with that from a living Nautilus shell. The prominent negative Sr isotope excursions known from the Middle Permian, Jurassic and Cretaceous probably have their origins in intensive plate tectonic activity, followed by enhanced hydrothermal activity at the mid-ocean ridges (mantle volcanism) which supplied low radiogenic Sr to seawater. The maximum positive (radiogenic) shift in the lower Mesozoic Sr isotope curve (Lower Triassic peak) was likely caused by a significant expansion of dry land surfaces (Dabie-Sulu Triassic orogeny) and their intensive silicate weathering in conditions of extreme warming and aridity in the very end of the Smithian, followed by warm and humid conditions in the late Spathian, which apparently resulted in a significant oceanic input of radiogenic Sr through riverine flux. The comparatively high 87Sr/86Sr ratio obtained from the living Nautilus shell is probably a function of both the Alpine orogeny, which was accompanied by significant continental weathering and input of radiogenic Sr to the oceans, and the weakening of mantle volcanism.

90Sr content in 90Y-labeled SIR-spheres and Zevalin.

Science.gov (United States)

Metyko, John; Erwin, William; Poston, John; Jimenez, Sandra

2014-11-01

Three different 90Y internally administered radionuclide therapies are currently used in both standard-of-care and clinical trial procedures atMD Anderson Cancer Center. TheraSphere and SIR-Spheres therapies utilize 90Y-labeled microspheres, while Zevalin is an 90Y-labeled radioimmunotherapeutic agent. Several publications have indicated radionuclidic impurities resulting from 90Y production methods. The 90Y in SIR-Spheres and Zevalin are produced from a 90Sr/90Y generator, which leaves measurable quantities of 90Sr in the final product. TheraSphere 90Y is produced in a nuclear reactor which results in a large number of impurities, most notably 88Y and 91Y. Product information sheets reference these impurities with specific limits given. These limits represent a tiny fraction of the total product activity, and in the case of TheraSphere and SIR-Spheres gamma-emitting impurities, this has been verified in the literature. An analysis of 90Sr impurities in SIR-Spheres and Zevalin is presented in this paper. Impurity quantities were found to be within the vendors’ documented limits.

Over-expression of SR-cyclophilin, an interaction partner of nuclear pinin, releases SR family splicing factors from nuclear speckles

International Nuclear Information System (INIS)

Lin, C.-L.; Leu, Steve; Lu, M.-C.; Ouyang Pin

2004-01-01

Pre-mRNA splicing takes place within a dynamic ribonucleoprotein particle called the spliceosome and occurs in an ordered pathway. Although it is known that spliceosome consists of five small nuclear RNAs and at least 50 proteins, little is known about how the interaction among the proteins changes during splicing. Here we identify that SR-cyp, a Moca family of nuclear cyclophilin, interacts and colocalizes with nuclear pinin (pnn), a SR-related protein involving in pre-mRNA splicing. Nuclear pnn interacts with SR-cyp via its C-terminal RS domain. Upon SR-cyp over-expression, however, the subnuclear distribution of nuclear pnn is altered, resulting in its redistribution from nuclear speckles to a diffuse nucleoplasmic form. The diffuse subnuclear distribution of nuclear pnn is not due to epitope masking, accelerated protein turnover or post-translational modification. Furthermore, we find that SR-cyp regulates the subnuclear distribution of other SR family proteins, including SC35 and SRm300, in a similar manner as it does on nuclear pnn. This result is significant because it suggests that SR-cyp plays a general role in modulating the distribution pattern of SR-like and SR proteins, similar to that of Clk (cdc2-like kinase)/STY on SR family splicing factors. SR-cyp might direct its effect via either alteration of protein folding/conformation or of protein-protein interaction and thus may add another control level of regulation of SR family proteins and modification of their functions

89Sr and 90Sr in atmospheric precipitations in May 1986 in Bucharest-Magurele area

International Nuclear Information System (INIS)

Paunescu, N.; Vata, I.

1987-08-01

Sr-89 and Sr-90 were determined in the fallout of May 1986. The maximum values of 335 Bq/(m 2 * 6 hours) and 110 Bq/(m 2 * 6 hours) were observed at May 2 and 5. Throughout May 1986 a quantity of 860 Bq/m 2 of Sr-90 deposited from the fallout in the Bucharest -Magurele area was determined. (authors)

Rapid determination of 90Sr impurities in freshly 'generator eluted'90Y for radiopharmaceutical preparation

International Nuclear Information System (INIS)

Bonardi, Mauro L.; Martano, Luigi; Groppi, Flavia; Chinol, Marco

2009-01-01

90 Y is one of the most useful radionuclides for radioimmunotherapeutic applications and has a half-life (t 1/2 =64.14 h) suitable for most therapeutic applications, beta particles of high energy and decays to a stable daughter. It is significant that 90 Y is available conveniently and inexpensively from a radionuclide 'generator' by decay of its parent, 90 Sr. Nevertheless, current and planned clinical applications with [ 90 Y] labelled compounds employ activity levels that cannot be readily obtained from an in-house generator, but from commercial sources. We have evaluated Eichrom's Sr-resin, either as an 'in-house' generator or as a fast QC method for analysis of 90 Y solutions. In particular, for the development as a generator, we investigated the percentage of the radio-Sr in the first 8 M HNO 3 eluate: in this fraction the concentration of 90 Sr must be smaller than 10 -5 % (recommendations of the International Commission on Radiological Protection). For evaluation as a rapid QC method, we analyzed the concentration of 90 Y in all the fractions containing 'only' radio-Sr: 90 Y should not be present in these eluates. After the collection of β - and γ spectra and analysis of them, we concluded that commercial Sr-resin minicolumn cannot give us the results expected; we developed an in-house system loaded with 4 mL of Sr-resin which gave better results as a generator and a rapid QC method.

EPR and TL-based beta dosimetry measurements in various tooth components contaminated by 90Sr

International Nuclear Information System (INIS)

Veronese, I.; Fattibene, P.; Cantone, M.C.; De Coste, V.; Giussani, A.; Onori, S.; Shishkina, E.A.

2008-01-01

Thermoluminescence-based beta dosimetry, previously proposed for the estimate of the internal contamination in teeth, and EPR has been used in this paper to investigate the homogeneity of 90 Sr contamination and of dose within nine teeth of one person born in the year of the onset of waterborne radioactive releases of the Mayak plutonium facility. A large deviation of dose and activity distributions in both enamel and radical dentine of the various teeth was observed. Average dose was 27±7Gy in enamel and 0.90±0.31Gy in radical dentine. Average 90 Sr concentration was 52±8Bq/g in enamel and 5±2Bq/g in radical dentine. The observed deviation around the mean value of dose and 90 Sr concentration can be explained due to the specific mineral evolution of each tooth at the time of Sr intake. In the same donor, a negative correlation was also observed between radical dentine and enamel for the 90 Sr specific activity as well for the dose. Similar analyses performed on one massive molar belonging to a second donor revealed absence of correlation between dose and 90 Sr concentration in the same tissue, indicating a dose contribution from 90 Sr present in neighbouring tissue compartments. Systematic differences in cumulated dose and activity levels between the lingual and the buccal parts of crown dentine and of enamel were also observed

SKI's and SSI's review of SKB's safety report SR-Can

International Nuclear Information System (INIS)

Dverstorp, Bjoern; Stroemberg, Bo

2008-03-01

This report summarises SKI's and SSI's joint review of the Swedish Nuclear Fuel and Waste Management Co's (SKB) safety report SR-Can (SKB TR-06-09). SR-Can is the first assessment of post-closure safety for a KBS-3 spent nuclear fuel repository at the candidate sites Forsmark and Laxemar, respectively. The analysis builds on data from the initial stage of SKB's surface-based site investigations and on data from full-scale manufacturing and testing of buffer and copper canisters. SR-Can can be regarded as a preliminary version of the safety report that will be required in connection with SKB's planned licence application for a final repository in late 2009. The main purpose of the authorities' review is to provide feedback to SKB on their safety reporting as part of the pre-licensing consultation process. However, SR-Can is not part of the formal licensing process. In support of the authorities' review three international peer review teams were set up to make independent reviews of SR-Can from three perspectives, namely integration of site data, representation of the engineered barriers and safety assessment methodology, respectively. Further, several external experts and consultants have been engaged to review detailed technical and scientific issues in SR-Can. The municipalities of Oesthammar and Oskarshamn where SKB is conducting site investigations, as well NGOs involved in SKB's programme, have been invited to provide their views on SR-Can as input to the authorities' review. Finally, the authorities themselves, and with the help of consultants, have used independent models to reproduce part of SKB's calculations and to make complementary calculations. All supporting review documents are published in SKI's and SSI's report series. The main findings of the review are: -SKB's safety assessment methodology is overall in accordance with applicable regulations, but part of the methodology needs to be further developed for the licence application. -SKB's quality

87Sr/86Sr ratios in hydrothermal waters and deposits from the east pacific rise at 210N

International Nuclear Information System (INIS)

Albarede, F.; Michard, A.; Minster, J.F.; Michard, G.

1981-01-01

87 Sr/ 86 Sr ratios of three hydrothermal waters collected on the East Pacific Rise at 21 0 N define a mixing line between seawater and a hydrothermal end-member at 0.7030 which is derived by seawater-basalt interaction at ca. 350 0 C and water/rock ratio of about 1.5. Sr concentrations are not affected in the process while Mg uptake from seawater is almost complete. Up to 2/3 of this hydrothermal component is involved in anhydrite precipitation while the Sr isotopic ratio in sulfides (chalcopyrite + sphalerite) cannot be distinguished from that of sulfate. It is estimated that ca. 1 x 10 10 moles of strontium are yearly cycled in the hydrothermal systems of mid-oceanic ridges, thereby affecting the 87 Sr/ 86 Sr budget of seawater. Mass balance between river runoff, limestone precipitation and ridge basalt alteration suggests that the 87 Sr/ 86 Sr ratios of the river runoff are in the range 0.7097-0.7113, and are largely dominated by limestone alteration. (orig.)

Synthetic clay excels in 90Sr removal

International Nuclear Information System (INIS)

Komarneni, Sridhar; Kodama, Tatsuya; Paulus, William J.; Carlson, C.

2000-01-01

Tests with actual ground water from Hanford site, and fundamental studies of 2Na + →Sr 2+ exchange equilibria revealed that a synthetic clay is extremely selective for 90 Sr with a high capacity for uptake. Comparative studies with existing Sr selective ion exchangers clearly revealed that the present synthetic clay exhibited the best performance for 90 Sr removal from actual ground water collected from three different locations at Hanford. This novel Sr ion sieve is expected to be useful for the decontamination of the environment after accidental release and contamination with 90 Sr. (c) 2000 Materials Research Society

[Quality of conventional release verapamil prescription in patients with arterial hypertension].

Science.gov (United States)

Machado-Alba, J E; Giraldo-Giraldo, C; Machado-Duque, M E

2015-01-01

To identify patients who were being treated for hypertension with conventional release verapamil (CRV), and to notify the professional responsible for their health care on cardiovascular risk to which they are exposed and achieve a reduction in the number of patients who are treated with this drug. A quasi-experimental prospective before and after study without a control group was conducted on 7289 patients diagnosed with hypertension who were on treatment with CRV, between October 1, 2012 and December 31, 2012 in 8 Colombian cities, collected from a database for dispensing medicines. Socio-demographic and pharmacological variables were evaluated. A total of 108 educational interventions were performed on those responsible for their health care, and evaluated within three months with the proportion of suspension of the prescriptions of CRV being evaluated. Multivariate analysis was performed using SPSS 22.0. The mean age of patients was 67.9±11.8 years (range: 26-96 years), of which 70.6% were men. Withdrawal of treatment with CRV was achieved in a total of 1922 patients (26.3% of users), distributed as follows: 1160 (60.4%) were the presentation of 120mg, while 762 (39.6%) the 80mg. The variable being treated in the city of Medellin (OR: 17.6; 95% CI: 11.949 to 25.924; P<.01) was statistically significantly associated with the replacement of CRV for another antihypertensive. A relatively moderate adherence to recommendations about the proper use of CRV in hypertensive patients, was found. Intervention programs that reduce inappropriate prescribing of potential risks to patients of insurance companies and cities where the change was not achieved, must be enforced. Copyright © 2014 SECA. Published by Elsevier Espana. All rights reserved.

The influence of Sr on the microstructure, degradation and stress corrosion cracking of the Mg alloys - ZK40xSr.

Science.gov (United States)

Chen, Lianxi; Bin, Yuanhong; Zou, Wenqi; Wang, Xiaojian; Li, Wei

2017-02-01

In the present work, new magnesium (Mg) alloys (Mg-4Zn-0.6Zr-xSr, x=0, 0.4, 0.8, 1.2, 1.6wt%; ZK40xSr) were prepared and studied as potential biodegradable materials. The influence of strontium (Sr) addition on the properties of the new Mg alloys was investigated, which included microstructure, corrosion degradation, and the stress corrosion cracking (SCC) susceptibility. The average grain size of the ZK40Sr was approximately 100µm, which was significantly smaller than that of ZK40 alloy without Sr (402.3±40.2µm). The size of grain boundaries precipitates in the ZK40xSr alloys gradually increased with the increase of Sr content. The grain boundaries finally showed a continuously distribution and net-like shape. The degradation test showed that the average degradation rate of the ZK40xSr alloys increased with the increase of Sr addition. In the case of Mg-4Zn-0.6Zr, the degradation rate was 2.2mgcm -2 day -1 , which was lower than that of Mg-4Zn-0.6Zr-1.6Sr (4.93mgcm -2 day -1 ). When the ZK40xSr alloys were immersed in m-SBF, the rod-like Sr-contained hydroxyapatite (HA) substance was detected, which was known to enhance cell growth around bone implants. The fracture surfaces of the as-cast Mg-4Zn-0.6Zr-1.6Sr were shown intergranular stress corrosion cracking (IGSCC) patterns. The increase of SCC susceptibility of the higher Sr ZK40xSr alloys was attributed to the increase of micro-galvanic corrosion between the α-Mg and the grain boundaries precipitates. The SCC susceptibility values were ≈0.13 and ≈0.41 for the Mg-4Zn-0.6Zr-0.4Sr and the Mg-4Zn-0.6Zr-1.6Sr, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Surface modeling and chemical solution deposition of SrO(SrTiO3)n Ruddlesden-Popper phases

International Nuclear Information System (INIS)

Zschornak, M.; Gemming, S.; Gutmann, E.; Weissbach, T.; Stoecker, H.; Leisegang, T.; Riedl, T.; Traenkner, M.; Gemming, T.; Meyer, D.C.

2010-01-01

Strontium titanate (STO) is a preferred substrate material for functional oxide growth, whose surface properties can be adjusted through the presence of Ruddlesden-Popper (RP) phases. Here, density functional theory (DFT) is used to model the (1 0 0) and (0 0 1) surfaces of SrO(SrTiO 3 ) n RP phases. Relaxed surface structures, electronic properties and stability relations have been determined. In contrast to pure STO, the near-surface SrO-OSr stacking fault can be employed to control surface roughness by adjusting SrO and TiO 2 surface rumpling, to stabilize SrO termination in an SrO-rich surrounding or to increase the band gap in the case of TiO 2 termination. RP thin films have been epitaxially grown on (0 0 1) STO substrates by chemical solution deposition. In agreement with DFT results, the fraction of particular RP phases n = 1-3 changes with varying heating rate and molar ratio Sr:Ti. This is discussed in terms of bulk formation energy.

Construction of the seawater 87Sr/86Sr curve for the Cenozoic and Cretaceous: supporting data

International Nuclear Information System (INIS)

Koepnick, R.B.; Burke, W.H.; Denison, R.E.; Hetherington, E.A.; Nelson, H.F.; Otto, J.B.; Waite, L.E.

1985-01-01

We present the data used to construct the Cenozoic and Cretaceous portion of the Phanerozoic curve of seawater 87 Sr/ 86 Sr that had been given in summary form by W.H. Burke and coworkers. All Cenozoic samples (128) and 22 Cretaceous samples are foram-nannofossil oozes and limestones from DSDP cores distributed among 13 sites in the Atlantic, Pacific and Indian Oceans, and the Caribbean Sea. Non-DSDP Cretaceous samples (126) include limestone, anhydrite and phosphate samples from North America, Europe and Asia. Determination of the 87 Sr/ 86 Sr value of seawater at particular times in the past is based on comparison of ratios derived from coeval marine samples from widely separated geographic areas. The general configuration of the Cenozoic and Cretaceous curve appears to be strongly influenced by the history of plate interactions and sea-floor spreading. Specific rises and falls in the 87 Sr/ 86 Sr of seawater, however, may be caused by a variety of factors such as variation in lithologic composition of the crust exposed to weathering, configuration and topographic relief of continents, volcanic activity, rate of sea-floor spreading, extent of continental inundation by epeiric seas, and variations in both climate and paleo-oceanographic conditions. Many or all of these factors are probably related to global tectonic processes, yet their combined effect on the temporal variation of seawater 87 Sr/ 86 Sr can complicate a direct plate-tectonic interpretation for portions of the seawater curve. (Auth.)

Enthalpies of formation of Cd0.917Sr0.083, Cd0.857Sr0.143 and Cd0.667Sr0.333 intermetallic compounds

International Nuclear Information System (INIS)

Agarwal, Renu; Singh, Ziley

2008-01-01

Cadmium is expected to be the solvent for pyrochemical processing of the metallic nuclear fuel. Therefore, thermodynamic properties of cadmium with various fuel and clad elements are of interest. Enthalpies of formation of the intermetallic compounds of Cd-Sr system, Cd 0.917 Sr 0.083 , Cd 0.857 Sr 0.143 and Cd 0.667 Sr 0.333 were determined by precipitation using Calvet calorimeter. Enthalpies of formation of the compounds were found to be -3.05 ± 0.5 kJ mol -1 at 723 K, -14.2 ± 0.7 kJ mol -1 at 843 K and -28.4 ± 0.8 kJ mol -1 at 863 K, respectively. Enthalpies of formation of Cd 0.917 Sr 0.083 and Cd 0.857 Sr 0.143 were also determined by partial enthalpy of formation measurements and the values were found to be -3.9 ± 1.1 kJ mol -1 at 723 K and -13.42 ± 1.2 kJ mol -1 at 843 K, respectively. Miedema model was used to estimate the enthalpies of formation of these compounds and the estimated values were compared with the experimentally determined values

About chemical and biological stimulation of bioleaching of 90Sr from different types of soil

International Nuclear Information System (INIS)

Buravlev, E.P.; Trishin, V.V.; Svyatun, O.V.; Berlizov, A.N.; Kim, In.S.; Ivanov, V.N.

2000-01-01

The results of investigation carried out in the frame of international cooperation between the NASU and KOSEF on the creation of effective methods of purification of radioactively polluted soil were performed. The influence of methanogenic, surface-reducing, nitrifying and thiobacilli and also their joint activity with different chemical ingredients on bioleaching of 90 Sr from typical South Korea red soil,artificially radioactively polluted by 90 Sr, and technogenically polluted by the radionuclides from influenced zone of ChNPP was studied, The presence of the largest effect of thiobacilli on soil was shown

Thermodynamic Modeling of Sr/TRU Removal

International Nuclear Information System (INIS)

Felmy, A.R.

2000-01-01

This report summarizes the development and application of a thermodynamic modeling capability designed to treat the Envelope C wastes containing organic complexants. A complete description of the model development is presented. In addition, the model was utilized to help gain insight into the chemical processes responsible for the observed levels of Sr, TRU, Fe, and Cr removal from the diluted feed from tank 241-AN-107 which had been treated with Sr and permanganate. Modeling results are presented for Sr, Nd(III)/Eu(III), Fe, Cr, Mn, and the major electrolyte components of the waste (i.e. NO 3 , NO 2 , F,...). On an overall basis the added Sr is predicted to precipitate as SrCO 3 (c) and the MnO 4 - reduced by the NO 2 - and precipitated as a Mn oxide. These effects result in only minor changes to the bulk electrolyte chemistry, specifically, decreases in NO 2 - and CO 3 2- , and increases in NO 3 - and OH - . All of these predictions are in agreement with the experimental observations. The modeling also indicates that the majority of the Sr, TRU's (or Nd(III)/Eu(III)) analogs, and Fe are tied up with the organic complexants. The Sr and permanganate additions are not predicted to effect these chelate complexes significantly owing to the precipitation of insoluble Mn oxides or SrCO 3 . These insoluble phases maintain low dissolved concentrations of Mn and Sr which do not affect any of the other components tied up with the complexants. It appears that the removal of the Fe and TRU'S during the treatment process is most likely as a result of adsorption or occlusion on/into the Mn oxides or SrCO 3 , not as direct displacement from the complexants into precipitates. Recommendations are made for further studies that are needed to help resolve these issues

How does stochastic resonance work within the human brain? - Psychophysics of internal and external noise

International Nuclear Information System (INIS)

Aihara, Takatsugu; Kitajo, Keiichi; Nozaki, Daichi; Yamamoto, Yoshiharu

2010-01-01

We review how research on stochastic resonance (SR) in neuroscience has evolved and point out that the previous studies have overlooked the interaction between internal and external noise. We propose a new psychometric function incorporating SR effects, and show that a Bayesian adaptive method applied to the function efficiently estimates the parameters of the function. Using this procedure in visual detection experiments, we provide significant insight into the relationship between internal and external noise in SR within the human brain.

Elastic properties of Sr- and Mg-doped lanthanum gallate at elevated temperature

Science.gov (United States)

Okamura, T.; Shimizu, S.; Mogi, M.; Tanimura, M.; Furuya, K.; Munakata, F.

The elastic moduli, i.e., Young's modulus, shear modulus and Poisson's ratio, of a sintered La 0.9Sr 0.1Ga 0.8Mg 0.2O 3- δ bulk have been experimentally determined in the temperature range from room temperature to 1373 K using a resonance technique. Anomalous elastic properties were observed over a wide temperature range from 473 to 1173 K. In the results for internal friction and in X-ray diffraction measurements at elevated temperature, two varieties of structural changes were seen in La 0.9Sr 0.1Ga 0.8Mg 0.2O 3- δ in the examined temperature range. The results agreed with the findings of a previous crystallographic study of the same composition system by Slater et al. In addition, the temperature range in which a successive structural change occurred in La 0.9Sr 0.1Ga 0.8Mg 0.2O 3- δ was the same as that exhibiting the anomalous elastic properties. Taking all the results together, it can be inferred that the successive structural change in the significant temperature range is responsible for the elastic property anomaly of La 0.9Sr 0.1Ga 0.8Mg 0.2O 3- δ.

Using 87Sr/86Sr ratios to investigate changes in stream chemistry during snowmelt in the Provo River, Utah, USA

Science.gov (United States)

Hale, C. A.; Carling, G. T.; Fernandez, D. P.; Nelson, S.; Aanderud, Z.; Tingey, D. G.; Dastrup, D.

2017-12-01

Water chemistry in mountain streams is variable during spring snowmelt as shallow groundwater flow paths are activated in the watershed, introducing solutes derived from soil water. Sr isotopes and other tracers can be used to differentiate waters that have interacted with soils and dust (shallow groundwater) and bedrock (deep groundwater). To investigate processes controlling water chemistry during snowmelt, we analyzed 87Sr/86Sr ratios, Sr and other trace element concentrations in bulk snowpack, dust, soil, soil water, ephemeral channels, and river water during snowmelt runoff in the upper Provo River watershed in northern Utah, USA, over four years (2014-2017). Strontium concentrations in the river averaged 20 ppb during base flow and decreased to 10 ppb during snowmelt runoff. 87Sr/86Sr ratios were around 0.717 during base flow and decreased to 0.715 in 2014 and 0.713 in 2015 and 2016 during snowmelt, trending towards less radiogenic values of mineral dust inputs in the Uinta Mountain soils. Ephemeral channels, representing shallow flow paths with soil water inputs, had Sr concentrations between 7-20 ppb and 87Sr/86Sr ratios between 0.713-0.716. Snowpack Sr concentrations were generally soils that contain accumulated dust deposits with a less radiogenic 87Sr/86Sr ratio. These results suggest that flow paths and atmospheric dust are important to consider when investigating variable solute loads in mountain streams.

Preparation and crystal structure of SrCu/sub 2/Sb/sub 2/ and SrZnBi/sub 2/

Energy Technology Data Exchange (ETDEWEB)

Cordier, G; Eisenmann, B; Schaefer, H [Technische Hochschule Darmstadt (Germany, F.R.). Fachbereich Anorganische Chemie und Kernchemie

1976-10-01

SrCu/sub 2/Sb/sub 2/ and SrZnBi/sub 2/ have been prepared and analytically and structurally characterized. SrCu/sub 2/Sb/sub 2/ crystallizes tetragonal in the CaBe/sub 2/Ge/sub 2/ structure type. SrZnBi/sub 2/ has its own structure type. In both structures the transition metal atoms form with the semimetal atoms tetragonal pyramids, which are connected by common edges of the basis to twodimensional sheets. These sheets are separated in the case of SrCu/sub 2/Sb/sub 2/ by single sheets of strontium atoms, in the case of SrZnBi/sub 2/ by double sheets of strontium atoms in which fourfold nets of Bi atoms are located.

Immune System Modifications Induced in a Mouse Model of Chronic Exposure to (90)Sr.

Science.gov (United States)

Synhaeve, Nicholas; Musilli, Stefania; Stefani, Johanna; Nicolas, Nour; Delissen, Olivia; Dublineau, Isabelle; Bertho, Jean-Marc

2016-03-01

Strontium 90 ((90)Sr) remains in the environment long after a major nuclear disaster occurs. As a result, populations living on contaminated land are potentially exposed to daily ingesting of low quantities of (90)Sr. The potential long-term health effects of such chronic contamination are unknown. In this study, we used a mouse model to evaluate the effects of (90)Sr ingestion on the immune system, the animals were chronically exposed to (90)Sr in drinking water at a concentration of 20 kBq/l, for a daily ingestion of 80-100 Bq/day. This resulted in a reduced number of CD19(+) B lymphocytes in the bone marrow and spleen in steady-state conditions. In contrast, the results from a vaccine experiment performed as a functional test of the immune system showed that in response to T-dependent antigens, there was a reduction in IgG specific to tetanus toxin (TT), a balanced Th1/Th2 response inducer antigen, but not to keyhole limpet hemocyanin (KLH), a strong Th2 response inducer antigen. This was accompanied by a reduction in Th1 cells in the spleen, consistent with the observed reduction in specific IgG concentration. The precise mechanisms by which (90)Sr acts on the immune system remain to be elucidated. However, our results suggest that (90)Sr ingestion may be responsible for some of the reported effects of internal contamination on the immune system in civilian populations exposed to the Chernobyl fallout.

Spectroscopic and electric dipole properties of Sr+Ar and SrAr systems including high excited states

Science.gov (United States)

Hamdi, Rafika; Abdessalem, Kawther; Dardouri, Riadh; Al-Ghamdi, Attieh A.; Oujia, Brahim; Gadéa, Florent Xavier

2018-01-01

The spectroscopic properties of the fundamental and several excited states of Sr+Ar and SrAr, Van der Waals systems are investigated by employing an ab initio method in a pseudo-potential approach. The potential energy curves and the spectroscopic parameters are displayed for the 1-10 2Σ+, 1-6 2Π and 1-3 2Δ electronic states of the Sr+Ar molecule and for the 1-6 1Σ+, 1-4 3Σ+, 1-3 1,3Π and 1-3 1,3Δ states of the neutral molecule SrAr. In addition, from these curves, the vibrational levels and their energy spacing are deduced for Σ+, Π and Δ symmetries. The spectra of the permanent and transition dipole moments are studied for the 1,3Σ+ states of SrAr, which are considered to be two-electron systems and 2Σ+ states of the single electron Sr+Ar ion. The spectroscopic parameters obtained for each molecular system are compared with previous theoretical and experimental works. A significant correlation revealed the accuracy of our results.

Sr - an element shows the way - Applications of Sr isotopes for provenance, tracing and migration (Invited)

Science.gov (United States)

Prohaska, T.; Irrgeher, J.; Zitek, A.; Teschler Nicola, M.

2010-12-01

Strontium - named after the small Scottish town Strontian - as such is an element with little popularity. Firstly described by Martin Heinrich Klaproth in 1798, the metal is used in metallurgy to some extent whereas its compounds are interesting in glass industries, electronics and pyrotechnics. The element has chemical similarity to Ca and makes up 1/60 of the earth’s amount of the latter. Nonetheless, it is its isotopic composition which makes Sr so interesting for a large number of scientists. The natural composition of the four naturally occurring isotopes (84Sr, 86Sr 87Sr and 88Sr) varies in nature due to the radioactive decay of 87Rb to 87Sr. Thus, it was early recognized as geochronometer especially in Ca rich matrices. With increasing precision of applied methodology, the natural variation of the 87Sr/86Sr isotope ratio (analyzed at first mainly by thermal ionization mass spectrometry (TIMS)) became more and more popular in provenance studies. The natural variation of the ratio is mainly determined by the geological age and the original composition of the rock and can be used therefore as fingerprint of the local geology. The ratio is transferred with no significant fractionation via the water into plants and finally via the food chain into animal and human tissues (especially bones and teeth). As the element is chemically similar to Ca, it appears in most matrices. The use for provenance studies is supported by the fact that the long half life (4.8 x 1010 years) does not lead to an alteration during the time scales which are investigated (from recent samples to human or animal skeletal remains which date back up to 30.000 BC). The uniqueness of the system besides the natural variation is defined by the ubiquity in nature and the relatively high (and thus measurable) elemental concentration in most tissues. It was finally the advent of multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) which augmented the number of applications

Epitaxial growth and thermodynamic stability of SrIrO3/SrTiO3 heterostructures

Science.gov (United States)

Groenendijk, D. J.; Manca, N.; Mattoni, G.; Kootstra, L.; Gariglio, S.; Huang, Y.; van Heumen, E.; Caviglia, A. D.

2016-07-01

Obtaining high-quality thin films of 5d transition metal oxides is essential to explore the exotic semimetallic and topological phases predicted to arise from the combination of strong electron correlations and spin-orbit coupling. Here, we show that the transport properties of SrIrO3 thin films, grown by pulsed laser deposition, can be optimized by considering the effect of laser-induced modification of the SrIrO3 target surface. We further demonstrate that bare SrIrO3 thin films are subject to degradation in air and are highly sensitive to lithographic processing. A crystalline SrTiO3 cap layer deposited in-situ is effective in preserving the film quality, allowing us to measure metallic transport behavior in films with thicknesses down to 4 unit cells. In addition, the SrTiO3 encapsulation enables the fabrication of devices such as Hall bars without altering the film properties, allowing precise (magneto)transport measurements on micro- and nanoscale devices.

Quest for secondary μSR signals for Fe3O4 using MaxEnt: a Verwey phase transition study.

Science.gov (United States)

Boekema, C.; Colebaugh, A.; Lee, A.-L.; Lin, I.; Cabot, A.; Morante, C.

Most muon-spin rotation (μSR) time series for magnetite (Fe3O4) have been interpreted in terms of one μSR frequency signal. Its Fourier transform appears to confirm this internal magnetic field. Yet many time series show a beat pattern, strongly suggesting a second signal with a close-by frequency. We are searching for secondary signals in zero-field Fe3O4 μ SR data using Maximum Entropy, a recently developed technique more sensitive than curve fitting and/or Fourier transformation. There is also another dilemma namely: the upper signal found for Fe3O4 has a local magnetic field larger than the maximum allowable vectorial sum of external and internal contributions. However, the (non)occurrence of secondary signals may shed light on the nature of the Verwey phase transition and its precursors in the Fe3O4 Mott-Wigner glass between Tv (123 K) and twice Tv (247 K). Research supported by LANL-DOE, SETI-NASA, SJSU & AFC.

87Sr/86Sr ratios in permo-carboniferous sea water from the analyses of well-preserved brachiopod shells

International Nuclear Information System (INIS)

Popp, B.N.; Anderson, T.F.

1986-01-01

Sr isotopic analyses of well-preserved portions of Permo-Carboniferous brachiopods distributed globally confirm the general shape of the Sr isotope age curve established by previous workers for this time interval. There is little variation between the SR isotopic composition of unaltered portions of brachiopods and that of portions of the same shell interpreted to be diagenetically altered (based on cathodoluminescence, elemental, and stable isotopic data). However, the Sr isotopic composition in diagenetically altered micritic matrix adjacent to the shell is more radiogenic. The Sr isotopic composition in the unaltered portions of calcitic megafossils has potential as a stratigraphic tool. (author)

Review of SR 97 performance assessment

International Nuclear Information System (INIS)

Glynn, P.D.

2000-01-01

This review has identified many technical problems in the SR 97 performance assessment. The general impression of this reviewer is that SKB has been disingenuous in its performance assessment effort. It has not cited important differences of opinion with its own views. Furthermore, there are many inconsistencies in the SR 97 report that all together leave the impression that there are many more uncertainties in the SR 97 performance assessment than SKB would perhaps care to admit. Additionally, despite SKB's statements to the contrary, many of the analyses conducted for the SR 97 performance assessment can be clearly shown not to have been based on 'conservative' assumptions. Finally, SKB has made little effort to consider possible coupling effects between their different scenarios in SR 97. This is a serious flaw in the SR 97 performance assessment. The comments in this review should not be taken to imply that the KBS-3 nuclear waste disposal method will not be able to meet the safety and radiation protection requirements which SKI and SSI have specified in recent years. Instead, my conclusion is simply that the SR 97 performance assessment of the KBS-3 method would have been more believable had it been based on a forthright and comprehensive discussion of facts, uncertainties and opinions, and on a more conservative choice of assumptions. As it stands, the SR 97 performance assessment is not very credible

87Sr/86Sr isotopes in grapes of different cultivars: A geochemical tool for geographic traceability of agriculture products.

Science.gov (United States)

Tescione, Ines; Marchionni, Sara; Casalini, Martina; Vignozzi, Nadia; Mattei, Massimo; Conticelli, Sandro

2018-08-30

87 Sr/ 86 Sr was determined on fresh red and white grapes, soils and rocks from three selected vineyards to verify the isotopic relationships between the fruit of the vine and geologic substrata of vineyards. 87 Sr/ 86 Sr were determined on sampled grapes of four different harvest years and different grape varieties, on bioavailable fraction of soils, on whole soils, and on bedrocks from the geo-pedological substratum of the vineyards. The vineyards chosen for the experimental works belong to an organic farming winery and thus cultivation procedures were strictly controlled. Grapes were sampled during the harvests of four different but consecutive years with 87 Sr/ 86 Sr that does not change reflecting the values of the soil bioavailable fraction. No variations among grapes from different vine cultivars were observed. A strict isotope relationship with soil bio-available fraction was observed. These findings demonstrate the reliability of 87 Sr/ 86 Sr, even at a very small scale, for food products geographic origin assessment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Development of 87Sr/86Sr maps as targeted strategy to support wine quality.

Science.gov (United States)

Durante, Caterina; Bertacchini, Lucia; Cocchi, Marina; Manzini, Daniela; Marchetti, Andrea; Rossi, Maria Cecilia; Sighinolfi, Simona; Tassi, Lorenzo

2018-07-30

This study summarizes the results obtained from a systematic and long-term project aimed at the development of tools to assess the provenance of food in the oenological sector. In particular, 87 Sr/ 86 Sr isotope ratios were measured on statistically representative set of soils, vine branches and wines sampled in the production district of Modena, worldwide known for the Lambrusco wines production. The obtained data were used to build strontium isotopic maps able to objectively support the Lambrusco PDO wines origin as well as other products of the Modena district. Finally, a strong relationship was found between the 87 Sr/ 86 Sr isotope ratios of soils and vine branches on a large scale, highlighting and confirming once more the idea that plants can also represent an optimal sampling device to support geographical traceability. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Inventory of Depressive Symptomatology Self Report (IDS-SR: Psychometric properties of the Indonesian version.

Directory of Open Access Journals (Sweden)

Retha Arjadi

Full Text Available Depression screening and examination in Indonesia are highly challenging due to the disproportionately low number of mental health professionals in comparison to the Indonesian population. Self-report questionnaires on depression are cost-effective and time-efficient. The current study investigates the psychometric properties of the Indonesian Inventory of Depressive Symptomatology Self Report (IDS-SR.The participants were 904 Indonesians (aged 16-61; 50.2% female, recruited via an online survey using Qualtrics. Confirmatory factor analysis of the one-factor, three-factor, and four-factor model were explored. Convergent and divergent validity of the total score of the Indonesian IDS-SR and each factor were examined, as well as the Cronbach's Alpha reliability. In addition, an optimal cut-off score for the Indonesian IDS-SR was established using ROC curve analysis.The three-factor model of "cognitive/mood", "anxiety/arousal", and "sleep disturbance" was the best fit with the Indonesian IDS-SR data. Convergent and divergent validity were good. Cronbach's Alpha reliability was excellent for the total score, good for the factors "cognitive/mood" and "anxiety/arousal", but insufficient for the factor "sleep disturbance". The optimal cut-off score of the Indonesian IDS-SR was 14, with 87% sensitivity and 86% specificity.As a multifactorial instrument to measure depression that has good validity and reliability, the Indonesian IDS-SR can be used to assess depressive symptoms for the purpose of research and clinical practice. The optimal cut-off score of the Indonesian IDS-SR is in accordance with the internationally used cut-off score.

Immune competence in 90Sr-exposed, adult thymectomized and antilymphocyteglobulin-treated CBA mice. Pt. 1

International Nuclear Information System (INIS)

Bierke, P.

1989-01-01

CBA mice subjected to either adult thymectomy, internal exposure to 90 Sr or antilymphocyteglobulin treatment separately, or to combinations of the three were tested for cellular immune competence using their reaction to allogenic skin grafts. Peripheral blood white cell counts did not reveal any obvious correlation between the degree of mononuclear cell depletion and the ability to accept grafts, suggesting that the particular treatments depleted specific fractions of mononuclear cells, differing in their extent of involvement in the rejection process. No single treatment alone induced a significant prolongation in the time elapsed before graft rejection. Adult thymectomy followed by appropriate antilymphocyteglobulin treatment induced severe lymphocytopenia and a profound suppression of the cell-mediate immune system, as evidenced by the acceptance of allogenic skin grafts. When applied to 90 Sr-preexposed mice the same treatment induced lifelong acceptance of grafts, indicating a similar, though weaker immunosuppressive impact of 90 Sr. Hence it was possible to significantly enhance immunosuppression in 90 Sr-exposed mice. This in vivo model should be useful when investigating the role of immunological responsiveness in radiation carcinogenesis. (orig.)

Alteration in DNA structure, molecular responses and Na+ -K+ -ATPase activities in the gill of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) in response to sub-lethal verapamil.

Science.gov (United States)

Ajima, Malachy N O; Pandey, Pramod K; Kumar, Kundan; Poojary, Nalini

2018-01-01

The ecotoxicological consequences of residues from pharmaceutical drugs on aquatic biota have necessitated the development of sensitive and reliable techniques to assess the impact of these xenobiotics on aquatic organisms. This study investigated the alteration in DNA structure, molecular responses and the activities of Na + -K + -ATPase and antioxidant enzymes in the gill of Nile tilapia, Oreochromis niloticus, exposed to long-term effects at the concentrations (0.14, 0.28 and 0.57mgL -1 ) of verapamil in static renewal system for 15, 30, 45 and 60 days. Evaluation of DNA structure, using single cell gel electrophoresis, revealed certain degree of DNA damages in the gill in a time and concentration-dependent relationship. Transcription of mRNA of superoxide dismutase (sod), catalase (cat) and heat shock protein (hsp70) genes in the gill of the fish showed the genes were up-regulated. Na + -K + -ATPase activity was inhibited in a concentration and time dependent manner. The indices of oxidative stress biomarkers (lipid peroxidation and carbonyl protein) as well as superoxide dismutase, glutathione peroxidase, glutathione-S-transferase were elevated in the treated fish in comparison to the control. Further, the level of reduced glutathione and catalase activity were inhibited at 0.28mgL -1 after day 30. Long-term exposure to sub-lethal concentration of verapamil can cause DNA damages, molecular effects and oxidative stress in O. niloticus. The biomarkers analysed can be used as early warning signals in environmental biomonitoring and assessment of drug contamination in aquatic ecosystem. Copyright © 2017 Elsevier Inc. All rights reserved.

New internal standard method for activation analysis and its application. Determination of Co, Ni, Rb, Sr in pepperbush by means of photon activation

Energy Technology Data Exchange (ETDEWEB)

Yagi, M.; Masumoto, K. (Tohoku Univ., Sendai (Japan). Lab. of Nuclear Science)

1984-08-01

A new internal standard method for activation analysis has been developed. In this method a suitable element present originally in the sample is used as an internal standard and the comparative standard is prepared by applying the standard addition method to the duplicated sample. The present method has the great advantages that the comparative standard spiked with the element of interest has the same matrix as the sample, and then the amount of the element to be determined in the sample can be evaluated easily by using a very simple equation even though the sample and comparative standard are irradiated separately by particles with different flux. Neither correction of the inhomogeneities of flux between the sample and comparative standard, nor that of the self-shielding effects are necessary for the present method. The usefulness of the method was examined through the determination of Co, Ni, Rb and Sr in pepperbush by means of photon activation, and the precision and accuracy of the method were proved to be valid. 29 refs.

Review of SR 97

International Nuclear Information System (INIS)

Voss, C.I.

2000-01-01

The safety analysis conducted by SKB for SR 97 is impressive in terms of both scale and content. In addition to an eventual solution to Sweden's nuclear waste isolation question, much general scientific knowledge of real value in other applications will be created as a by-product of SKB's efforts. This review focuses on those geoscience aspects of SR 97 that have the most important effects on radionuclide release from each barrier. Indeed, SR 97 elucidates the most important geoscience parameters that control releases from the near field and the far field; these comprise mainly the transport resistance parameter, and the sorption coefficients for each nuclide, the matrix diffusion coefficient, and the Darcy flux. The Main Report is the most important document in SR 97 inasmuch as it is the only one that brings together all of the supporting work to answer the question of safety. Unfortunately pervading the good supporting work done is the impression that the Main Report is not balanced, that it emphasizes optimistic aspects and downplays the negative. SKB specifies 3 main requirements to guarantee proper repository function: a non-oxidizing subsurface environment, temperatures less than 100 C, and a mechanically stable low-permeability buffer surrounding the canisters. The first and third requirements are not thoroughly proven by SKB. One source of near-field doubt stems from the consequences of combinations of scenarios in which several negative events are linked, while the effect of each scenario is mainly evaluated only independently in SR 97. More pertinently, disastrous breakdown of complex systems may occur due to a chain of linked failures. For example, in the glacial scenario: high ground-water flow (possible ablation of buffer and high fluid transport), change in ground-water chemistry (even the possibility of oxidizing conditions), new flow paths, significant changes in mechanical stress and possible motion along faults (which may also generate new flow

Preparation of Sr adsorptive fiber by impregnating with crown ether derivative for 90Sr measurement

International Nuclear Information System (INIS)

Horita, Takuma; Asai, Shiho; Hanzawa, Yukiko; Kitatsuji, Yoshihiro; Konda, Miki; Saito, Kyoichi; Fujiwara, Kunio; Sugo, Takanobu

2017-01-01

A Sr adsorption fiber was prepared for rapid analysis of 90 Sr content in the fiber using radiation-induced emulsion graft polymerization and subsequent chemical modification. A polyethylene fiber with a diameter of 13 μm was first immersed in a methanol solution of an epoxy-group-containing vinyl monomer, glycidyl methacrylate (GMA), and polyoxyethylene sorbitol ester (Tween20) as a surfactant for the graft-polymerization of GMA. Octadecylamine was then bound to a polymer chain extending from the fiber surface, providing hydrophobicity to the polymer chain. Dicyclohexano-18-crown-6 (DCH18C6) was finally impregnated onto the polymer chain via a hydrophobic interaction between the octadecyl moiety of the polymer chain and the cyclohexyl moiety of DCH18C6. The fiber surface structure, characterized by DCH18C6 molecules loosely entangled with polymer chains, allowed for the rapid adsorption of Sr ions at an adsorption rate of approximately 100-times higher than that of a commercially available Sr-selective resin (Sr Resin ® ). (author)

Preparation of 90Sr-90Y generator

International Nuclear Information System (INIS)

Jin Xiaohai; Yu Haibin; Zhang Jinming; Zhang Peixin; Lin Qiongfang

1990-01-01

In recent years, 90 Y has been considered as one of the best radionuclides for tumor radioimmunotherapy when chelated to tumor-associated antibodies. This evaluation is based on the superior properties of this radionuclide (suitable half-life, pure β-ray emitter of intermediate energy, stable daughters, and suitable chemical properties) and because it is available as a radionuclide generator product by decay of its 28a parent 90 Sr. The experimental conditions of 90 Sr- 90 Y generator are described. The elution efficiency of 90 Sr- 90 Y generator reaches 98%. One of the most important problems is the 90 Sr contamination breakthrough from the generator. The level of 90 Sr contamination must be controlled to the clinical standard. The cation exchange resin 732 (100-150 mesh) was successfully used for the separation of 90 Y from 90 Sr. The method used by the authors provides a 90 Y-HAc solution which is very simple and safe for administration to the patients. 90 Y was separated from 90 Sr almost completely, the level of the 90 Sr contamination per 740 MBq 90 Y product was only 0.74 kBq. However the toxicity of 90 Sr is extremely high, the human life-time permissible dose is 74 kBq, then 740 MBq of 90 Y is allowed to be administrated to a patient for 50-100 times

90Sr- 90Y and 89Sr beta radioactivity measurement in milk samples using a proportional counter

International Nuclear Information System (INIS)

Mananes, A.; Perez Santos, C.; Martinez Churiaque, F.

1987-01-01

A thin window glas flow proportional counter is used to measure the 90 Sr- 90 Y and 89 Sr beta radioactivity in milk samples. A chemical procedure is used to separate strontium-yttrium from the other radionuclides present in milk. A calculation of the total efficiency of the system is performed which includes an empirical estimation of the backscattering factor. The calibration of the whole process allows the determination of the 90 Sr activity within 10% relative error in spite of uncertainties in the recovery yields of strontium and yttrium. No 89 Sr activity has been detected, and the mean value obtained for the 90 Sr activity in nine milk samples of Cantabria is 0.115 Bq/1 with a minimum detectable activity of 0.0105 Bq. (author) 18 refs

Atomic layer epitaxy of Ruddlesden-Popper SrO(SrTiO3)n films by means of metalorganic aerosol deposition

International Nuclear Information System (INIS)

Jungbauer, M.; Hühn, S.; Moshnyaga, V.; Egoavil, R.; Tan, H.; Verbeeck, J.; Van Tendeloo, G.

2014-01-01

We report an atomic layer epitaxial growth of Ruddlesden-Popper (RP) thin films of SrO(SrTiO 3 ) n (n = ∞, 2, 3, 4) by means of metalorganic aerosol deposition (MAD). The films are grown on SrTiO 3 (001) substrates by means of a sequential deposition of Sr-O/Ti-O 2 atomic monolayers, monitored in-situ by optical ellipsometry. X-ray diffraction and transmission electron microscopy (TEM) reveal the RP structure with n = 2–4 in accordance with the growth recipe. RP defects, observed by TEM in a good correlation with the in-situ ellipsometry, mainly result from the excess of SrO. Being maximal at the film/substrate interface, the SrO excess rapidly decreases and saturates after 5–6 repetitions of the SrO(SrTiO 3 ) 4 block at the level of 2.4%. This identifies the SrTiO 3 substrate surface as a source of RP defects under oxidizing conditions within MAD. Advantages and limitations of MAD as a solution-based and vacuum-free chemical deposition route were discussed in comparison with molecular beam epitaxy

Therapeutic result of radioactive nuclide 90Sr/90Y treatment in patients with benign prostatic hypertrophy (BPH)

International Nuclear Information System (INIS)

Chen Hanchao; Li Yuying

2008-01-01

Objective: To study the effect of radioactive nuclide 90 Sr/ 90 Y treatment in patients with benign prostatic hypertrophy (BPH). Methods: Sixty patients with BPH were treated with a course of transurethral radioactive nuclide 90 Sr/ 90 Y therapy. Results: The severity of BPH was assessed with four parameters: maximal flow rate (MFR), volume of residual urine (VRU), international prostatic symptom score (IPSS) and volume (size) of prostate. In this series, the total effective rate was 93.33% with no treatment- related mortality. Favorable changes of the parameters after a course of radioactive nuclide therapy were significant. Conclusion: Radioactive nuclide 90 Sr/ 90 Y therapy for patients with BPH was safe, easily performed and quite effective. This procedure is worth popularizing in appropriate patients. (authors)

Electronic and structural properties of Sr2YSbO6

International Nuclear Information System (INIS)

Ortiz-Diaz, O.; Jairo Arbey Rodriguez, M.; Fajardo, F.; Landinez Tellez, D.A.; Roa-Rojas, J.

2007-01-01

The electronic and structural properties of the cubic perovskite Sr 2 YSbO 6 were predicted from ab initio calculations. Such properties were obtained using the density functional theory (DFT). The full-potential (linearized) augmented plane-wave ((L)APW) method was used, as it is implemented in wien2k code. We have optimized the volume of the unitary cell and the internal x parameter. The lattice constant (a) and x determine some length bonds. We have found that a=8.405 A, x=0.26177, and the bond lengths Y-O and Sb-O are 2.20 and 2.00 A, respectively. Additionally, Sr 2 YSbO 6 was prepared experimentally by the solid-state reaction method using stoichiometric mixtures of high purity (99.99%). By means of X-ray and Rietveld analysis, the main structural features were determined. The experimental lattice parameter is a=8.249 A, which differs about 1.9% of the value obtained using DFT. The bulk modulus is ∼133 GPa, which is not measured experimentally. DFT predicts that Sr 2 YSbO 6 is an indirect semiconductor and magnetic behavior does not have to be expected because at Fermi level the dominant orbitals are p-oxygen. The gap of the material is at least 2.5 eV

87Sr/86Sr dating and preliminary interpretation of magnetic susceptibility logs of giant piston cores from the Rio Grande Rise in the South Atlantic

Science.gov (United States)

Lacasse, Christian Michel; Santos, Roberto Ventura; Dantas, Elton Luiz; Vigneron, Quentin; de Sousa, Isabela Moreno Cordeiro; Harlamov, Vadim; Lisniowski, Maria Aline; Pessanha, Ivo Bruno Machado; Frazão, Eugênio Pires; Cavalcanti, José Adilson Dias

2017-12-01

Giant piston cores recovered from shallow depths (optimized matching with an internationally recognized timescale of 87Sr/86Sr seawater variation through geological times. Depth-to-age conversion of the magnetic susceptibility logs was implemented based on the identification of correlative peaks between cores and the developed 87Sr/86Sr age model. The influence of Northern Hemisphere glaciation is reflected in these new stratigraphic logs by a gradual increase from ∼2.7 Ma in the lower signal of magnetic susceptibility (below background level), to values approaching the arithmetic means, likely reflecting an overall increase in terrigenous input. The Rio Grande Rise cores have very low Plio-Pleistocene sedimentation rates (∼0.4-0.8 cm/ka), similar to gravity cores from the oligotrophic subtropical South Atlantic (below ∼2000 mbsl), and for which an inverse correlation between carbonate content and magnetic susceptibility was established. The coring depths on the Rio Grande Rise encompass strong gradients in oxygen concentration and other seawater parameters that define today's AAIW/UCDW transition. Depth-dependent variation in sedimentation rates since the onset of Northern Hemisphere glaciation coincides with the incursion of intermediate waters (UCDW, AAIW) in response to the overall reduction of NADW export to the Southern Ocean. Background levels of magnetic susceptibility in the cores suggest that this variation is mainly attributed to terrigenous input. The source region of this material has yet to be traced by considering in particular the mineral composition and paramagnetic properties of the detrital clays.

Peculiarities of Sr-90 migration in the environment

International Nuclear Information System (INIS)

Romanov, G.N.; Stukin, D.A.; Aleksakhin, R.M.

1991-01-01

The Eastern Urals radioactive track which formed as a result of the Kyshtym accident constituted a natural experimental base for studying the dynamics of Sr-90 behaviour and migration in the environment. Sr-90 behaviour in soil depends on the processes involved in its physical migration horizontally (water runoff, wind transport) and vertically (effective diffusion), on the intensity with which the physico-chemical forms of strontium change, and primarily on Sr-90 incorporation into the soil-absorptive complex. Over 30 years the effective diffusion processes led to downward displacement of Sr-90 in undisturbed soil to a depth of 30 to 50 cm. In 1988 84-94% of the Sr-90 was located in the 10 cm layer as against 90% in the 2 cm layer in the initial 1 or 2 years. The amount of Sr-90 in mobile forms in leached chernozem and grey forest soil hardly changed over time, amounting to between 76 and 90%. In the first 5-10 years Sr-90 surface water runoff was about 0.2% (and Sr-90 wind resuspension 0.1-1.0%) per year of the Sr-90 inventory per unit area. Due to Sr-90 loss from the top soil layer the water runoff and wind resuspension processes decreased exponentially, halving every 4 to 5 years. In most cases, Sr-90 transfer from soil to plants via the roots does not involve discrimination of Sr-90 with regard to calcium, and therefore the Sr-90 accumulation level in various species of natural and agricultural plants depends on their calcium requirements and the amount of exchangeable calcium in the soil. This made it possible to work out quantitative indices for forecasting Sr-90 accumulation in various species of plants for given types of soil. As Sr-90 moves through the trophic chains (including the agricultural one) we find - depending on whether two adjoining links discriminate against it or not as regards calcium - that some organisms reject it while others concentrate it. When restoring farming on the contaminated territory the fact that cattle discriminated against Sr

Applicability of 87Sr/86Sr in examining return flow of irrigation water in highly agricultural watersheds in Japan

Science.gov (United States)

Yoshida, T.; Nakano, T.; Shin, K. C.; Tsuchihara, T.; Miyazu, S.; Kubota, T.

2017-12-01

Water flows in watersheds containing extensive areas of irrigated paddies are complex because of the substantial volumes involved and the repeated cycles of water diversion from, and return to, streams. For better management of low-flow conditions, numerous studies have attempted to quantify the return flow using the stable isotopes of water; however, the temporal variation in these isotopic compositions due to fractionation during evaporation from water surfaces hinders their application to watersheds with extensive irrigated paddies. In this study, we tested the applicability of the strontium isotopes (87Sr/86Sr, hereafter Sr ratio) for studying hydrological processes in a typical agricultural watershed located on the alluvial fan of the Kinu River, namely the Gogyo River, in central Japan. The Sr ratio of water changes only because of interactions with the porous media it flows through, or because of mixing with water that has different Sr ratios. We sampled water both at a single rice paddy, and on the watershed scale in the irrigated and non-irrigated periods. The soil water under the paddy decreased as sampling depth increased, and the soil water at a depth of 1.5 m showed a similar Sr ratio to the spring. The water sampled in the drainage channel with a concrete lined bottom showed a similar Sr ratio to the irrigation water, whereas that with a soil bottom was plotted between the plots of the irrigation water and shallow aquifer. These results suggest the Sr ratio decreases as it mixes with the soil water through percolation; whereas the Sr ratio will be less likely to change when water drains from paddies via surface pathways. The streamflow samples were plotted linearly on the Sr ratio and 1/Sr plot, indicating that the streamflow was composed of two end-members; the irrigation water and the shallow aquifer. The continuous decline in the Sr ratio along the stream suggests an exfiltration of water from the shallow aquifers. The stream water during the non

An open aperture z-scan study of Sr2CeO4 blue phosphor

International Nuclear Information System (INIS)

Seema, R.; Sandeep, C.S. Suchand; Philip, Reji; Kalarikkal, Nandakumar

2011-01-01

Highlights: → Sr 2 CeO 4 blue phosphor has been prepared by a solid state reaction method. → The XRD study confirms that the structure of the system is orthorhombic. → The TEM reveals that Sr 2 CeO 4 is composed of elongated spherical structures of length ∼0.2-0.6 μm. → The FFT of TEM, XRD peaks and the JCPDS values are compared, from which the Sr 2 CeO 4 phase is reconfirmed. → A z-scan measurement gives the effective two-photon absorption coefficient to be 3.9 x 10 -11 m/W. - Abstract: Sr 2 CeO 4 blue phosphor has been prepared by the solid-state reaction method. The X-ray diffraction (XRD) study confirms the structure of the system to be orthorhombic. High resolution electron transmission microscopy reveals that Sr 2 CeO 4 prepared by the solid state reaction method is composed of elongated spherical structures of length ∼0.2-0.6 μm and width ∼90-150 nm. The excitation spectrum shows a broad band which peaks at 275 nm. The emission spectrum shows a broad band which peaks at 467 nm when excited at 275 nm. The emission band is assigned to the energy transfer between the molecular orbital of the ligand and charge transfer (CT) state of the Ce 4+ ion. The Commission International de l'Eclairage (CIE) co-ordinates are x = 0.15, and y = 0.23. The nonlinear absorption behavior of Sr 2 CeO 4 has been investigated using the open aperture z-scan technique. The calculated effective two-photon absorption coefficient shows that the Sr 2 CeO 4 blue phosphor is a promising optical limiting material.

Hepatic Proteome Sensitivity in Rainbow Trout after Chronically Exposed to a Human Pharmaceutical Verapamil*

Science.gov (United States)

Li, Zhi-Hua; Li, Ping; Sulc, Miroslav; Hulak, Martin; Randak, Tomas

2012-01-01

Verapamil (VRP), a cardiovascular pharmaceutical widely distributed and persistent in the aquatic environment, has potential toxicity to fish and other aquatic organisms. However, the molecular mechanisms that lead to these toxic effects are not well known. In the present study, proteomic analysis has been performed to investigate the protein patterns that are differentially expressed in liver of rainbow trout exposed to sublethal concentrations of VRP (0.5, 27.0, and 270 μg/liter) for 42 days. Two-dimensional electrophoresis coupled with MALDI-TOF/TOF mass spectrometry was employed to detect and identify the protein profiles. The analysis revealed that the expression of six hepatic acidic proteins were markedly altered in the treatment groups compared with the control group; three proteins especially were significantly down-regulated in fish exposed to VRP at environmental related concentration (0.5 μg/liter). These results suggested that the VRP induce mechanisms against oxidative stress (glucose-regulated protein 78 and 94 and protein disulfide-isomerase A3) and adaptive changes in ion transference regulation (calreticulin, hyperosmotic glycine-rich protein). Furthermore, for the first time, protein Canopy-1 was found to be significantly down-regulated in fish by chronic exposure to VRP at environmental related levels. Overall, our work supports that fish hepatic proteomics analysis serves as an in vivo model for monitoring the residual pharmaceuticals in aquatic environment and can provide valuable insight into the molecular events in VRP-induced toxicity in fish and other organisms. PMID:21997734

Preparation and characterization of Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite for bone repair application

Directory of Open Access Journals (Sweden)

Hossein Mohammadi

2015-07-01

Full Text Available Objective(s: Hardystonite (HT is Zn-modified silicate bioceramics with promising results for bone tissue regeneration. However, HT possesses no obvious apatite formation. Thus, in this study we incorporated Sr and Ti into HT to prepare Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite and evaluated its in vitro bioactivity with the purpose of developing a more bioactive bone substitute material. Materials and methods:The HT and Sr-Ti-HT were prepared by mechanical milling and subsequent heat treatment. Calcium oxide (CaO, zinc oxide (ZnO and silicon dioxide (SiO2 (all from Merck were mixed with molar ratio of 2:1:2. The mixture of powders mixture was then milled in a planetary ball mill for 20 h. In the milling run, the ball-to-powder weight ratio was 10:1 and the rotational speed was 200 rpm. After synthesis of HT, 3% nanotitanium dioxide (TiO2, Degussa and 3% strontium carbonate (SrCO3, Merck were added to HT and then the mixture was ball milled and calcined at 1150°C for 6 h. Simultaneous thermal analysis (STA, X-ray diffraction (XRD, Transmission electron microscopy (TEM and Fourier transform infra-red spectroscopy (FT-IR performed to characterize the powders. Results:XRD and FT-IR confirmed the crystal phase and silicate structure of HT and TEM images demonstrated the nanostructure of powders. Further, Sr-Ti-HT induced apatite formation and showed a higher human mesenchymal stem cell (hMSCs adhesion and proliferation compared to HT. Conclusion:Our study revealed that Sr-Ti-HT with a nanostructured crystal structure of 50 nm, can be prepared by mechanical activation to use as biomaterials for orthopedic applications.

The influence of Sr content in calcium phosphate coatings

International Nuclear Information System (INIS)

Lindahl, Carl; Pujari-Palmer, Shiuli; Hoess, Andreas; Ott, Marjam; Engqvist, Håkan; Xia, Wei

2015-01-01

In this study calcium phosphate coatings with different amounts of strontium (Sr) were prepared using a biomineralization method. The incorporation of Sr changed the composition and morphology of coatings from plate-like to sphere-like morphology. Dissolution testing indicated that the solubility of the coatings increased with increased Sr concentration. Evaluation of extracts (with Sr concentrations ranging from 0 to 2.37 μg/mL) from the HA, 0.06Sr, 0.6Sr, and 1.2Sr coatings during in vitro cell cultures showed that Sr incorporation into coatings significantly enhanced the ALP activity in comparison to cells treated with control and HA eluted media. These findings show that calcium phosphate coatings could promote osteogenic differentiation even in a low amount of strontium. - Highlights: • Calcium phosphate coating doping with low Sr contents was prepared via a biomineralization process. • The solubility of the coatings increased with increased Sr concentration. • Present findings show the potential that Sr has on promoting osteogenic differentiation even in a low amount

The Newsworthiness of International Terrorism.

Science.gov (United States)

Weimann, Gabriel; Brosius, Hans-Bernd

1991-01-01

Investigates the newsworthiness of international terrorism. Relates the concept of deviance as a predictor of newsworthiness to the specific attributes of terrorist events and their impact on media selection (coverage or no coverage) and prominence of coverage. (SR)

S1P in HDL promotes interaction between SR-BI and S1PR1 and activates S1PR1-mediated biological functions: calcium flux and S1PR1 internalization.

Science.gov (United States)

Lee, Mi-Hye; Appleton, Kathryn M; El-Shewy, Hesham M; Sorci-Thomas, Mary G; Thomas, Michael J; Lopes-Virella, Maria F; Luttrell, Louis M; Hammad, Samar M; Klein, Richard L

2017-02-01

HDL normally transports about 50-70% of plasma sphingosine 1-phosphate (S1P), and the S1P in HDL reportedly mediates several HDL-associated biological effects and signaling pathways. The HDL receptor, SR-BI, as well as the cell surface receptors for S1P (S1PRs) may be involved partially and/or completely in these HDL-induced processes. Here we investigate the nature of the HDL-stimulated interaction between the HDL receptor, SR-BI, and S1PR1 using a protein-fragment complementation assay and confocal microscopy. In both primary rat aortic vascular smooth muscle cells and HEK293 cells, the S1P content in HDL particles increased intracellular calcium concentration, which was mediated by S1PR1. Mechanistic studies performed in HEK293 cells showed that incubation of cells with HDL led to an increase in the physical interaction between the SR-BI and S1PR1 receptors that mainly occurred on the plasma membrane. Model recombinant HDL (rHDL) particles formed in vitro with S1P incorporated into the particle initiated the internalization of S1PR1, whereas rHDL without supplemented S1P did not, suggesting that S1P transported in HDL can selectively activate S1PR1. In conclusion, these data suggest that S1P in HDL stimulates the transient interaction between SR-BI and S1PRs that can activate S1PRs and induce an elevation in intracellular calcium concentration.

The inverse F-BAR domain protein srGAP2 acts through srGAP3 to modulate neuronal differentiation and neurite outgrowth of mouse neuroblastoma cells.

Directory of Open Access Journals (Sweden)

Yue Ma

Full Text Available The inverse F-BAR (IF-BAR domain proteins srGAP1, srGAP2 and srGAP3 are implicated in neuronal development and may be linked to mental retardation, schizophrenia and seizure. A partially overlapping expression pattern and highly similar protein structures indicate a functional redundancy of srGAPs in neuronal development. Our previous study suggests that srGAP3 negatively regulates neuronal differentiation in a Rac1-dependent manner in mouse Neuro2a cells. Here we show that exogenously expressed srGAP1 and srGAP2 are sufficient to inhibit valporic acid (VPA-induced neurite initiation and growth in the mouse Neuro2a cells. While ectopic- or over-expression of RhoGAP-defective mutants, srGAP1(R542A and srGAP2(R527A exert a visible inhibitory effect on neuronal differentiation. Unexpectedly, knockdown of endogenous srGAP2 fails to facilitate the neuronal differentiation induced by VPA, but promotes neurite outgrowth of differentiated cells. All three IF-BAR domains from srGAP1-3 can induce filopodia formation in Neuro2a, but the isolated IF-BAR domain from srGAP2, not from srGAP1 and srGAP3, can promote VPA-induced neurite initiation and neuronal differentiation. We identify biochemical and functional interactions of the three srGAPs family members. We propose that srGAP3-Rac1 signaling may be required for the effect of srGAP1 and srGAP2 on attenuating neuronal differentiation. Furthermore, inhibition of Slit-Robo interaction can phenocopy a loss-of-function of srGAP3, indicating that srGAP3 may be dedicated to the Slit-Robo pathway. Our results demonstrate the interplay between srGAP1, srGAP2 and srGAP3 regulates neuronal differentiation and neurite outgrowth. These findings may provide us new insights into the possible roles of srGAPs in neuronal development and a potential mechanism for neurodevelopmental diseases.

Mapping and characterization of wheat stem rust resistance genes SrTm5 and Sr60 from Triticum monococcum.

Science.gov (United States)

Chen, Shisheng; Guo, Yan; Briggs, Jordan; Dubach, Felix; Chao, Shiaoman; Zhang, Wenjun; Rouse, Matthew N; Dubcovsky, Jorge

2018-03-01

The new stem rust resistance gene Sr60 was fine-mapped to the distal region of chromosome arm 5A m S, and the TTKSK-effective gene SrTm5 could be a new allele of Sr22. The emergence and spread of new virulent races of the wheat stem rust pathogen (Puccinia graminis f. sp. tritici; Pgt), including the Ug99 race group, is a serious threat to global wheat production. In this study, we mapped and characterized two stem rust resistance genes from diploid wheat Triticum monococcum accession PI 306540. We mapped SrTm5, a previously postulated gene effective to Ug99, on chromosome arm 7A m L, completely linked to Sr22. SrTm5 displayed a different race specificity compared to Sr22 indicating that they are distinct. Sequencing of the Sr22 homolog in PI 306540 revealed a novel haplotype. Characterization of the segregating populations with Pgt race QFCSC revealed an additional resistance gene on chromosome arm 5A m S that was assigned the official name Sr60. This gene was also effective against races QTHJC and SCCSC but not against TTKSK (a Ug99 group race). Using two large mapping populations (4046 gametes), we mapped Sr60 within a 0.44 cM interval flanked by sequenced-based markers GH724575 and CJ942731. These two markers delimit a 54.6-kb region in Brachypodium distachyon chromosome 4 and a 430-kb region in the Chinese Spring reference genome. Both regions include a leucine-rich repeat protein kinase (LRRK123.1) that represents a potential candidate gene. Three CC-NBS-LRR genes were found in the colinear Brachypodium region but not in the wheat genome. We are currently developing a Bacterial Artificial Chromosome library of PI 306540 to determine which of these candidate genes are present in the T. monococcum genome and to complete the cloning of Sr60.

Chernobyl 90Sr in bilberries from Poland

International Nuclear Information System (INIS)

Mietelski, J.W.; Vajda, N.

1997-01-01

As part of a detailed survey on the contamination of Polish forests 90 Sr activity concentrations were determined in bilberries. Elevated 90 Sr levels were found in several samples from north-eastern Poland. The calculated maximum 90 Sr surface contamination was 2 kBq*m -2 . The correlation between 90 Sr and 137 Cs concentrations in bilberries was good for two sets of samples originating from two geographical areas of Poland indicating the local differences in radionuclide depositions from Chernobyl fallout. (author)

Modification of Sr on 4004 Aluminum Alloy

Science.gov (United States)

Guo, Erjun; Cao, Guojian; Feng, Yicheng; Wang, Liping; Wang, Guojun; Lv, Xinyu

2013-05-01

As a brazing foil, 4004 Al alloy has good welding performance. However, the high Si content decreases the plasticity of the alloy. To improve the plasticity of 4004 Al alloy and subsequently improve the productivity of 4004 Al foil or 434 composite foil, 4004 Al alloy was modified by Al-10%Sr master alloy. Modification effects of an additional amount of Sr, modification temperature, and holding time on 4004 aluminum alloy were studied by orthogonal design. The results showed that the greatest impact parameter of 4004 aluminum alloy modification was the additional amount of Sr, followed by holding time and modification temperature. The optimum modification parameters obtained by orthogonal design were as follows: Sr addition of 0.04%, holding time of 60 min, and modification temperature of 760°C. The effect of Sr addition on modification was analyzed in detail based on orthogonal results. With increasing of Sr addition, elongation of 4004 alloy increased at first, and decreased after reaching the maximum value.

Losses of Sr/sup 90/, Sr/sup 89/, and I/sup 131/ from fallout-contaminated plants

Energy Technology Data Exchange (ETDEWEB)

Martin, W E

1964-11-01

During the early period following local fallout, and during periods of maximal worldwide fallout, the entry of radionuclides into terrestrial food-chains is due primarily to the external contamination of plants and secondarily to the uptake of radionuclides from contaminated soil. Studies were undertaken to estimate the rates of radionuclide loss from fallout-contaminated vegetation and hence from the diets of herbivores living in a fallout field. On the fifth, fifteenth, thirtieth, and sixtieth days after an underground nuclear explosion (Operation Sedan) at the Nevada Test Site, plant samples were collected from twenty representative locations in the fallout field and analyzed to determined the concentrations (pc/g dry wt) of /sup 90/Sr, /sup 89/Sr, and /sup 131/I at the times of collections. While the radioactive half lives of /sup 90/Sr, /sup 89/Sr, and /sup 131/I are approximately 27.7 years, 53 days, and 8.04 days respectively, their average effective half-lives on fallout-contaminated plants, during the period from 5 to 30 days after the detonation, were 27.8 days, 17.8 days, and 5.0 days respectively. Losses of /sup 90/Sr were attributed to radioactive decay and to the removal of fallout particles and foliage by wind and/or other mechanical disturbances. Losses of /sup 90/Sr and /sup 89/Sr were attributed to radioactive decay and to the removal of fallout particles and foliage by wind and/or other mechanical disturbances. Losses of /sup 131/I were attributed to radioactive decay, to mechanical disturbance, and to the vaporization of /sup 131/I from the fallout particles retained on foliage.

Experimental evidence shows no fractionation of strontium isotopes ((87)Sr/(86)Sr) among soil, plants, and herbivores: implications for tracking wildlife and forensic science.

Science.gov (United States)

Flockhart, D T Tyler; Kyser, T Kurt; Chipley, Don; Miller, Nathan G; Norris, D Ryan

2015-01-01

Strontium isotopes ((87)Sr/(86)Sr) can be useful biological markers for a wide range of forensic science applications, including wildlife tracking. However, one of the main advantages of using (87)Sr/(86)Sr values, that there is no fractionation from geological bedrock sources through the food web, also happens to be a critical assumption that has never been tested experimentally. We test this assumption by measuring (87)Sr/(86)Sr values across three trophic levels in a controlled greenhouse experiment. Adult monarch butterflies were raised on obligate larval host milkweed plants that were, in turn, grown on seven different soil types collected across Canada. We found no significant differences between (87)Sr/(86)Sr values in leachable Sr from soil minerals, organic soil, milkweed leaves, and monarch butterfly wings. Our results suggest that strontium isoscapes developed from (87)Sr/(86)Sr values in bedrock or soil may serve as a reliable biological marker in forensic science for a range of taxa and across large geographic areas.

High magnetic field μSR instrument scientific case

International Nuclear Information System (INIS)

Amato, A.

2005-10-01

In order to gain more insight into the specific behavior of materials, it is often necessary to perform measurements as a function of different external parameters. Despite its high sensitivity to internal fields, this simple observation also applies for the μSR technique. The most common parameter which can be tuned during an experiment is the sample temperature. By using a range of cryostats, temperatures between 0.02 and 900 K can be covered at the PSI μSR Facility. On the other hand, and by using high-energy muons, pressures as high as 10'000 bars can nowadays be reached during μSR experiments. As will be demonstrated in the following Sections, the magnetic field is an additional external parameter playing a fundamental role when studying the ground state properties of materials in condensed matter physics and chemistry. However, the availability of high magnetic fields for μSR experiments is still rather limited. Hence, if on one hand the high value of the gyromagnetic ratio of the muon provides the high magnetic sensitivity of the method, on the other hand it can lead to very high muon-spin precession frequencies when performing measurements in applied fields (the muon-spin precession frequency in a field of 1 Tesla s 135.5 MHz). Consequently, the use of ultra-fast detectors and electronics is mandatory when measuring in magnetic fields exceeding 1 Tesla. If such fields are very intense when compared to the Earth magnetic field -4 Tesla), the energy associated with them is still modest in view of the thermal energy. Hence, the Zeeman energy splitting of a free electron in a magnetic field of 1 Tesla corresponds to a thermal energy as low as 0.67 Kelvin. It is worth mentioning that nowadays magnetic fields of the order of 10 to 15 Tesla are quite common in condensed matter laboratories and have opened up vast new exciting experimental possibilities. (author)

High magnetic field {mu}SR instrument scientific case

Energy Technology Data Exchange (ETDEWEB)

Amato, A

2005-10-15

In order to gain more insight into the specific behavior of materials, it is often necessary to perform measurements as a function of different external parameters. Despite its high sensitivity to internal fields, this simple observation also applies for the {mu}SR technique. The most common parameter which can be tuned during an experiment is the sample temperature. By using a range of cryostats, temperatures between 0.02 and 900 K can be covered at the PSI {mu}SR Facility. On the other hand, and by using high-energy muons, pressures as high as 10'000 bars can nowadays be reached during {mu}SR experiments. As will be demonstrated in the following Sections, the magnetic field is an additional external parameter playing a fundamental role when studying the ground state properties of materials in condensed matter physics and chemistry. However, the availability of high magnetic fields for {mu}SR experiments is still rather limited. Hence, if on one hand the high value of the gyromagnetic ratio of the muon provides the high magnetic sensitivity of the method, on the other hand it can lead to very high muon-spin precession frequencies when performing measurements in applied fields (the muon-spin precession frequency in a field of 1 Tesla s 135.5 MHz). Consequently, the use of ultra-fast detectors and electronics is mandatory when measuring in magnetic fields exceeding 1 Tesla. If such fields are very intense when compared to the Earth magnetic field < 10{sup -4} Tesla), the energy associated with them is still modest in view of the thermal energy. Hence, the Zeeman energy splitting of a free electron in a magnetic field of 1 Tesla corresponds to a thermal energy as low as 0.67 Kelvin. It is worth mentioning that nowadays magnetic fields of the order of 10 to 15 Tesla are quite common in condensed matter laboratories and have opened up vast new exciting experimental possibilities. (author)

Report on nuclear energy in SR Slovenia; Porocilo o uporabi jedrske energije v SR Sloveniji

Energy Technology Data Exchange (ETDEWEB)

NONE

1987-07-01

Currently Yugoslavia has one 632 MWe nuclear power plant (NPP) of PWR design, located at Krsko in the Socialist Republic (SR) of Slovenia. Krsko NPP, which is a two-loop plant, started power operation in 1981. In general, reactor safety activities in the SR of Slovenia are mostly related to upgrading the safety of our Krsko NPP and to developing capabilities for use in future units. This report presents the nuclear safety related legislation and organization of the corresponding regulatory body, and the activities related to nuclear safety of the participating organizations in the SR of Slovenia in 1987.

Neurotensin type 1 receptor-mediated activation of krox24, c-fos and Elk-1: preventing effect of the neurotensin antagonists SR 48692 and SR 142948.

Science.gov (United States)

Portier, M; Combes, T; Gully, D; Maffrand, J P; Casellas, P

1998-07-31

Stimulation of neurotensin (NT) type 1 receptors (NT1-R) in transfected CHO cells is followed by the activation of mitogen-activated protein kinases and the expression of the early response gene krox24. By making point mutations and internal deletions in the krox24 promoter, we show that proximal serum responsive elements (SRE) are involved in transcriptional activation by NT. In addition, we show that the related early response gene c-fos and the Ets protein Elk-1 are also induced by NT. The involvement of NT1-R in NT-mediated activation of krox24, c-fos and Elk-1 was demonstrated by the preventing effect of the specific antagonists SR 48692 and SR 142948. Finally, we show that the activation of krox24 and Elk-1 on the one hand, and that of c-fos on the other hand, result from independent transduction pathways since the former are pertussis toxin-sensitive whereas the latter is insensitive to pertussis toxin.

The transfer of {sup 137}Cs and {sup 90}Sr from feed to rabbits

Energy Technology Data Exchange (ETDEWEB)

Semioshkina, N. [GSF-Institut fuer Strahlenschutz, Ingolstaedter Landstr. 1, Postfach 1129, D-85788 Neuherberg (Germany)], E-mail: semi@gsf.de; Proehl, G. [GSF-Institut fuer Strahlenschutz, Ingolstaedter Landstr. 1, Postfach 1129, D-85788 Neuherberg (Germany); Savinkov, A. [The Scientific Research Agricultural Institute of the National Biotechnology Center, Ministry for Science and Higher Education of the Republic of Kazakhstan (SRAI), 480544 Gvardeiski (Kazakhstan); Voigt, G. [Agency' s Laboratories, Seibersdorf, IAEA, 1400-Vienna (Austria)

2007-11-15

Radiological assessment of the impact of nuclear weapons testing on the local population in the Semipalatinsk Test Site (STS) requires comprehensive site-specific information on radionuclide behaviour in the environment. However, information on radionuclide behaviour in the conditions of the STS is rather sparse and, in particular, there are no data in the literature on parameters of radionuclide transfer from feed to rabbit products which have been identified as contributors to internal dose to the inhabitants. The transfer of {sup 137}Cs and {sup 90}Sr to rabbit meat was studied under laboratory conditions in a controlled experiment with 32 locally bred rabbits maintained in the Kazakh Agricultural Research Institute. The equilibrium transfer coefficients for {sup 137}Cs and {sup 90}Sr from feed to rabbit meat were estimated to be 0.4 d kg{sup -1} and 0.15 d kg{sup -1}, respectively. The biological half-lives were estimated to be 0.1 d for {sup 137}Cs and 0.14 d for {sup 90}Sr. Whereas for {sup 137}Cs the distribution in the body is relatively homogeneous, there are large differences between the organs and tissues for {sup 90}Sr for which, as expected, the highest concentrations were found in bone.

Sr isotopic tracer study of the Samail ophiolite, Oman

International Nuclear Information System (INIS)

Lanphere, M.A.; Coleman, R.G.; Hopson, C.A.

1981-01-01

We have measured Rb and Sr concentrations and Sr isotopic compositions in 41 whole-rock samples and 12 mineral separates from units of the Samail ophiolite, including peridotite, gabbro, plagiogranite diabase dikes, and gabbro and websterite dikes within the metamorphic peridotite. Ten samples of cummulate gabbro from the Wadir Kadir section and nine samples from the Wadi Khafifah section have mean 87 Sr/ 86 Sr ratios and standard deviations of 0.70314 +- 0.00030 and 0.70306 +- 0.00034, respectively. The dispersion in Sr isotopic composition may reflect real heterogeneities in the magma source region. The average Sr isotopic composition of cumulate gabbro falls in the range of isotopic compositions of modern midocean ridge basalt. The 87 Sr/ 86 Sr ratios of noncumulate gabbro, plagiogranite, and diabase dikes range from 0.7034 to 0.7047, 0.7038 to 0.7046, and 0.7037 to 0.7061, respectively. These higher 87 Sr/ 86 Sr ratios are due to alteration of initial magmatic compositions by hydrothermal exchange with seawater. Mineral separates from dikes that cut harzburgite tectonite have Sr isotopic compositions which agree with that of cumulate gabbro. These data indicate that the cumulate gabbro and the different dikes were derived from partial melting of source regions that had similar long-term histories and chemical compositions

Thermal infrared and microwave absorbing properties of SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/polyaniline nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Hosseini, Seyed Hossein, E-mail: shhosseini@iiau.ac.ir [Department of Chemistry, Faculty of Science, Islamshahr Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Zamani, Parisa [Department of Applied Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Mousavi, S.Y. [Faculty of Passive Defense, Imam Hossein University, Tehran (Iran, Islamic Republic of)

2015-09-25

Graphical abstract: We have developed a new perspective of applications and properties of conducting polymers. The combination of absorption ability prepared nanocomposites in the present of PANI display a great potential in organization of shielding structures into thermal IR and microwave. Further investigations using other conducting polymers to demonstrate their capability for advance thermal IR and microwave shielding devices is under way. The application of these samples may improve the IR thermographic detection, catalysis, sensors, magnetic data storage, electromagnetic resonance wave absorption, photonic crystals, and microelectronic devices and military aspects. - Highlights: • The SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/PANI exhibited electric and electromagnetic properties. • The SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/PANI has shielding structures into thermal IR and microwave. • Increasing weight ratios and thicknesses will increase thermal IR ability. • Increasing weight ratios and thicknesses will increase microwave absorption ability. - Abstract: Polyaniline (PANI) as a unique polymer that also has electromagnetic absorption used as the substrate. In this research, SrTiO{sub 3} was synthesized as IR absorbent and core and then SrFe{sub 12}O{sub 19} as microwave absorbent was prepared on SrTiO{sub 3} via co-precipitation method as the first shell. As the next step, PANI was coated on SrTiO{sub 3}/SrFe{sub 12}O{sub 19} nanoparticles via in situ polymerization by multi core–shell structures (SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/PANI). Nanometer size and structures of samples were measured by TEM, XRD and FTIR. Morphology of nanocomposite was showed by SEM images. The magnetic and electric properties were also performed by VSM and four probe techniques. Thermal infrared (IR) absorption and microwave reflection loss of nanocomposites were investigated at 10–40 μm and 8–12 GHz, IR and microwave frequencies, respectively. The results showed that the Sr

82Sr--82Rb radioisotope generator

International Nuclear Information System (INIS)

Grant, P.M.; Erdal, B.R.; O'Brien, H.A.

1976-01-01

An improved 82 Sr- 82 Rb radioisotope generator system, based upon the complexing ion exchange resin Chelex-100, has been developed. Columns of this material can be easily and rapidly milked, and the Rb-Sr separation factor for a fresh generator was found to be greater than 10 7 . Approximately 80 percent of the 82 Rb present was delivered in a 15-ml volume of aqueous 0.2 M NH 4 Cl solution. After more than 6 liters of eluant had been put through the generator, the Rb-Sr separation factor was still observed to be greater than 10 5 , and no unusual strontium breakthrough behavior was seen in the system over nearly three 82 Sr half lives. 2 claims, no drawings

Autoradiography of 90Sr in developing rats

International Nuclear Information System (INIS)

Olsen, I.; Jonsen, J.

1979-01-01

The distribution patterns of 90 Sr in five littermate, 8-day-old Wistar rats were studied by whole body autoradiography. Rats were killed 15 min, 1, 4, 24, and 72 h after a single intraperitoneal injection of the isotope. Immediately after administration, 90 Sr was distributed throughout most of the soft tissues of the body. The soft tissue deposits had practically disappeared after 4 h. In the hard tissues of the body 90 Sr accumulated up to 24-72 h. Fifteen minutes after injection the uptake of 90 Sr in the enamel of the teeth was highest in the occlusal and incisal regions. 90 Sr gradually accumulated throughout the enamel and after 72 h its distribution in this layer was fairly uniform. Immediately after injection a narrow zone of radioactivity appeared in the dentin near the pulp. This zone broadened with time towards the dentinoenamel junction and included the intire dentin layer 72 h after injection. Initially, the uptake of 90 Sr was higher in the dentin than in the enamel, particularly in the cervical areas of the crown. This difference became less apparent with time. There was good correlation between the uptake in the teeth and bones, supporting the use of teeth as indicators of the 90 Sr body burden. (author)

Determination of 90Sr by liquid scintillation counting

International Nuclear Information System (INIS)

Cerchetti, Maria L.; Aghazarian, V.P.

2006-01-01

99m Tc, the result of the radioactive decay of 99 Mo, is one of the most applied radioisotopes in nuclear medicine and is used in nuclear medicine as a radiopharmaceutical product. It is important to ensure 99 Mo quality in order to fit the 99m Tc quality specifications. The main objective was to obtain a technique for 90 Sr determination in 99 Mo and environmental samples. The purification of 90 Sr is performed by extraction chromatography where crown-ether resin (Sr-Spec, Eichrom) was used. The measurement of the 90 Sr activity is performed by Liquid Scintillation Counting (LSC) using the double windows method. This method permits the 90 Sr determination without waiting until radiochemical equilibrium 90 Sr / 90 Y has been reached. The recovery factor was determined by gamma spectrometry with 85 Sr, and by gravimetry with stable strontium carrier solution. The minimum detectable activity was 0,05 Bq. The recovery factor was the major contribution in the total uncertainty. (author)

Test for the determination of 90Sr in soil

International Nuclear Information System (INIS)

1980-01-01

The standardized method is based on the chemical separation (extraction, precipitation, etc.) of 90 Sr from other fission products. After long-term storage for 90 Sr- 90 Y equilibrium the activity of the sample precipitated in the form of Y(COO) 2 is measured. The Sr yield coefficient is determined by 85 Sr tracer or by gravimetry. The test is applicable for the determination of 90 Sr contamination originating from fallout or from other sources in soil, when the concentration of 90 Sr is higher than 0.2-0.4 Bqg -1 (5-10 pCig -1 ). The error of the method is less than +-2% of the amount of the 90 Sr present. (Sz.J.)

Impact of P and Sr on solidification sequence and morphology of hypoeutectic Al–Si alloys: Combined thermodynamic computation and phase-field simulation

International Nuclear Information System (INIS)

Eiken, Janin; Apel, Markus; Liang, Song-Mao; Schmid-Fetzer, Rainer

2015-01-01

Even small amounts of Phosphorus and Strontium strongly affect the microstructure of hypoeutectic Al–Si alloys. P is an unavoidable trace element in commercial Al-alloys which causes formation of AlP particles as potent nucleation sites for eutectic (Si). Sr, in contrast, is purposely added to modify the morphology of eutectic (Si) towards fine coral-like fibers. It is hypothesized that Sr does not only alter the growth kinetics of (Si), but additionally prevents detrimental (Si) nucleation due to neutralization of AlP particles by Al 2 Si 2 Sr formation. This presumes that both AlP and Al 2 Si 2 Sr precipitate prior to (Si). Using a newly assessed thermodynamic database for the Al–Si–Sr–P system, critical P and Sr thresholds for pre-silicon formation of AlP and Al 2 Si 2 Sr were evaluated and mapped under equilibrium and Scheil conditions. The competitive precipitation of AlP, Al 2 Si 2 Sr and (Si) and its impact on the evolution of the eutectic morphology was further studied by 3D phase-field simulations. Effective anisotropy functions for the (Si) interface mobility considered Sr-induced internal twinning. Depending on whether subcritical or supercritical P and Sr contents were selected, either a fine lamellar structure, a coarse flaky structure, or the targeted fine fibrous eutectic structure was reproduced

Atomic layer epitaxy of Ruddlesden-Popper SrO(SrTiO{sub 3}){sub n} films by means of metalorganic aerosol deposition

Energy Technology Data Exchange (ETDEWEB)

Jungbauer, M.; Hühn, S.; Moshnyaga, V. [Erstes Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Egoavil, R.; Tan, H.; Verbeeck, J.; Van Tendeloo, G. [EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium)

2014-12-22

We report an atomic layer epitaxial growth of Ruddlesden-Popper (RP) thin films of SrO(SrTiO{sub 3}){sub n} (n = ∞, 2, 3, 4) by means of metalorganic aerosol deposition (MAD). The films are grown on SrTiO{sub 3}(001) substrates by means of a sequential deposition of Sr-O/Ti-O{sub 2} atomic monolayers, monitored in-situ by optical ellipsometry. X-ray diffraction and transmission electron microscopy (TEM) reveal the RP structure with n = 2–4 in accordance with the growth recipe. RP defects, observed by TEM in a good correlation with the in-situ ellipsometry, mainly result from the excess of SrO. Being maximal at the film/substrate interface, the SrO excess rapidly decreases and saturates after 5–6 repetitions of the SrO(SrTiO{sub 3}){sub 4} block at the level of 2.4%. This identifies the SrTiO{sub 3} substrate surface as a source of RP defects under oxidizing conditions within MAD. Advantages and limitations of MAD as a solution-based and vacuum-free chemical deposition route were discussed in comparison with molecular beam epitaxy.

Interplay between HIV Entry and Transportin-SR2 Dependency

Directory of Open Access Journals (Sweden)

Gijsbers Rik

2011-01-01

Full Text Available Abstract Background Transportin-SR2 (TRN-SR2, TNPO3, transportin 3 was previously identified as an interaction partner of human immunodeficiency virus type 1 (HIV-1 integrase and functions as a nuclear import factor of HIV-1. A possible role of capsid in transportin-SR2-mediated nuclear import was recently suggested by the findings that a chimeric HIV virus, carrying the murine leukemia virus (MLV capsid and matrix proteins, displayed a transportin-SR2 independent phenotype, and that the HIV-1 N74D capsid mutant proved insensitive to transportin-SR2 knockdown. Results Our present analysis of viral specificity reveals that TRN-SR2 is not used to the same extent by all lentiviruses. The DNA flap does not determine the TRN-SR2 requirement of HIV-1. We corroborate the TRN-SR2 independent phenotype of the chimeric HIV virus carrying the MLV capsid and matrix proteins. We reanalyzed the HIV-1 N74D capsid mutant in cells transiently or stably depleted of transportin-SR2 and confirm that the N74D capsid mutant is independent of TRN-SR2 when pseudotyped with the vesicular stomatitis virus glycoprotein (VSV-G. Remarkably, although somewhat less dependent on TRN-SR2 than wild type virus, the N74D capsid mutant carrying the wild type HIV-1 envelope required TRN-SR2 for efficient replication. By pseudotyping with envelopes that mediate pH-independent viral uptake including HIV-1, measles virus and amphotropic MLV envelopes, we demonstrate that HIV-1 N74D capsid mutant viruses retain partial dependency on TRN-SR2. However, this dependency on TRN-SR2 is lost when the HIV N74D capsid mutant is pseudotyped with envelopes mediating pH-dependent endocytosis, such as the VSV-G and Ebola virus envelopes. Conclusion Here we discover a link between the viral entry of HIV and its interaction with TRN-SR2. Our data confirm the importance of TRN-SR2 in HIV-1 replication and argue for careful interpretation of experiments performed with VSV-G pseudotyped viruses in

44/40Ca and 87Sr/86Sr isotopes as tracers of silicate weathering in small catchments of the Massif Central, France

Science.gov (United States)

Négrel, Philippe; Guerrot, Catherine; Millot, Romain; Petelet-Giraud, Emmanuelle; Bullen, Thomas

2013-04-01

We present calcium stable isotope and strontium radiogenic isotope data for soils and sediments developed on volcanic and igneous rocks forming small catchments in the Massif Central (France). Measurements of 44/40Ca isotope ratios (44/40Ca measured by the double spike method on TIMS and normalized to the value for seawater Ca in delta units) in rocks, sediments and soils from silicate catchments (e.g. granite and basalts) together with 87Sr/86Sr isotope ratios permit an examination of the relationships of these isotope systematics during weathering of silicate rocks. We have analysed the granite, weathered granite (arene) and saprolite, sediment and soil overlying the granite on one hand and the basanite, sediment and soil overlying the basanite on the other. The main bedrock in the volcanic zone (e.g. Allanche catchment) is 11 to 2.5 Ma basanite (nephelinitic to leucitic basalts) having SiO2 between 41-45 wt. %, Na2O + K2O bank have 87Sr/86Sr ratios greater than that of the arene with values increasing in the sediment from the surface down to soil. The 87Sr/86Sr vs. Rb/Sr variation observed in the volcanic area likewise confirms the weathering of low 87Sr/86Sr, low Rb/Sr phases in the bedrock, and there is a linear increase in 87Sr/86Sr and Rb/Sr ratios from those in the sediment up to the values observed in the soils. In the volcanic area, the basanite bedrock has 44/40Ca = -0.94 ± 0.05‰ (n = 7), while the soils and sediments have 44/40Ca of -0.75 to -1.13‰ and -0.79 to -1.01‰, respectively. These results suggest that Ca isotopes are not strongly fractionated during weathering of the basalt. The granite whole-rock has 44/40Ca of -1.29‰, while the soil and sediments have 44/40Ca of -1.93 to -2.07‰ and -1.98 to -2.81‰, respectively, with values decreasing as the Ca content decreases. The 44/40Ca ratios of arene, soil and sediment are similar to or less than that of K- feldspar, reflecting complete loss of the relatively heavy Ca from plagioclase and

In situ Sr/Sr investigation of igneous apatites and carbonates using laser-ablation MC-ICP-MS

DEFF Research Database (Denmark)

Bizzarro, Martin; Simonetti, A.; Stevenson, R.K.

2003-01-01

In situ Sr isotopic compositions of coexisting apatite and carbonate for carbonatites from the Sarfartoq alkaline complex, Greenland, have been determined by laser-ablation multicollector inductively coupled plasma mass spectrometry. This study is the first to examine the extent of Sr isotopic ho...

Hybrid HF-DFT comparative study of SrZrO{sub 3} and SrTiO{sub 3}(001) surface properties

Energy Technology Data Exchange (ETDEWEB)

Evarestov, R.A.; Bandura, A.V.; Alexandrov, V.E. [Department of Quantum Chemistry, St. Petersburg State University, 26 Universitetskii Prospekt, Stary Petergof, 198504 St. Petersburg (Russian Federation)

2006-10-15

Hybrid HF-DFT LCAO simulations of SrZrO{sub 3} and SrTiO{sub 3}(001) surface properties are performed in a single-slab model framework. The SrZrO{sub 3}(001) surface was studied by an ab initio method for the first time. Three slab models with different surface terminations including up to 8 atomic planes were used for calculation of the various surface characteristics (surface energies, atomic charges, density of electronic states). The dependence of the results on the chosen model and on the kind of d-element is analyzed. The dissimilarity in the surface oxygen atom contributions to the total density of states of two crystals is attributed to the more ionic nature of Zr-O bonds compared to Ti-O bonds. It is found that in the case of SrZrO{sub 3} the electronic density is biased towards the SrO-terminated surface and this surface should be more basic in nature than the SrO surface of SrTiO{sub 3} crystal. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Determination of the electrostatic potential distribution in Pt/Fe:SrTiO₃/Nb:SrTiO₃ thin-film structures by electron holography.

Science.gov (United States)

Marchewka, Astrid; Cooper, David; Lenser, Christian; Menzel, Stephan; Du, Hongchu; Dittmann, Regina; Dunin-Borkowski, Rafal E; Waser, Rainer

2014-11-10

We determined the electrostatic potential distribution in pristine Pt/Fe:SrTiO3/Nb:SrTiO3 structures by electron holography experiments, revealing the existence of a depletion layer extending into the Nb-doped bottom electrode. Simulations of potential profiles in metal-insulator-metal structures were conducted assuming different types and distributions of dopants. It is found that the presence of acceptor-type dopant concentrations at the Fe:SrTiO3/Nb:SrTiO3 interface with a donor-doped insulating layer provides a good match to the measured profile. Such acceptor-type interface concentrations may be associated with Sr vacancies on the Nb:SrTiO3 side of the bottom interface.

Using noble gases and 87Sr/86Sr to constrain heat sources and fluid evolution at the Los Azufres Geothermal Field, Mexico

Science.gov (United States)

Wen, T.; Pinti, D. L.; Castro, M. C.; Lopez Hernandez, A.; Hall, C. M.; Shouakar-Stash, O.; Sandoval-Medina, F.

2017-12-01

Geothermal wells and hot springs were sampled for noble gases' volume fraction and isotopic measurements and 87Sr/86Sr in the Los Azufres Geothermal Field (LAGF), Mexico, to understand the evolution of fluid circulation following three decades of exploitation and re-injection of used brines. The LAGF, divided into the Southern Production Zone (SPZ) and the Northern Production Zone (NPZ), is hosted in a Miocene to Pliocene andesitic volcanic complex covered by Quaternary rhyolitic-dacitic units. Air contamination corrected 3He/4He ratios (Rc) normalized to the atmospheric ratio (Ra=1.384 x 10-6), show a median value of 6.58 indicating a dominant mantle helium component. Contributions of crustal helium up to 53% and 18% are observed in NPZ and SPZ, respectively. Observations based on Rc/Ra and 87Sr/86Sr ratios points to the mixing of three magmatic sources supplying mantle helium to the LAGF: (1) a pure mantle He (Rc/Ra = 8) and Sr (87Sr/86Sr = 0.7035) source; (2) a pure mantle helium (Rc/Ra = 8) with some radiogenic Sr (87Sr/86Sr = 0.7049) source possibly resulting from Quaternary rhyolitic volcanism; and (3) a fossil mantle He component (Rc/Ra = 3.8) with some radiogenic Sr (87Sr/86Sr = 0.7038), corresponding possibly to the Miocene andesite reservoir. Intrusions within the last 50 kyrs from sources (1) and (2) are likely responsible for the addition of mantle volatiles and heat to the hydrothermal system of Los Azufres. He and Ar isotopes indicate that heat flow is transported by both convection and conduction. Atmospheric noble gas elemental ratios suggest that geothermal wells located closer to the western re-injection zone are beginning to be dominated by re-injection of used brines (injectate). The area affected by boiling in LAGF has further extended to the north and west since the last noble gas sampling campaign in 2009.

Thermodynamic modeling of the Sr-Co-Fe-O system

DEFF Research Database (Denmark)

Zhang, Wei Wei; Povoden-Karadeniz, Erwin; Chen, Ming

2016-01-01

This paper reviews and assesses phase equilibria and thermodynamic properties of phases in the Sr-Co-Fe-O system, with a focus on oxides, especially the SrCo1 - xFexO3 - δ perovskite. In our work, the SrCo1 - xFexO3 - δ perovskite was modeled with a three-sublattice model, where the three...... sublattices correspond to the A, B and oxygen sites in an ABO3 perovskite, respectively. A number of other important ternary oxide phases in Sr-Co-O and Sr-Co-Fe-O were also considered. Available thermodynamic and phase diagram data were carefully assessed. A thermodynamic description of Sr-Co-O was derived...... using the CALPHAD approach and was further extrapolated to that of Sr-Co-Fe-O. The thermodynamic database of Sr-Co-Fe-O established in this work allows for calculating phase diagrams, thermodynamic properties, cation distribution and defect chemistry properties, and therefore enables material...

Joint effect of 90Sr, alcohol and smoking on some immunological indices

International Nuclear Information System (INIS)

Shubik, V.M.; Mashneva, N.I.; Kupriyanova, V.M.

1986-01-01

The experiments with white non-inbred mice showed that combined chronic exposure of the animals, preexposed to 90 Sr to ethanol and caused more manifested changes in non-specific humoral immunity (bactericidal properties of blood serum) and in immunologic indices (autoantibodies, immune complexes) than chronic administration of the radionuclide alone. The obtained data proved the possibility of summation and potentiation of the effects of internal irradiation, alcohol and smoking

Factors affecting 90Sr uptake from the ration

International Nuclear Information System (INIS)

Knizhnikov, V.A.; Marej, A.N.; Borisov, B.K.; Petukhova, Eh.V.

1980-01-01

The dependence of 90 Sr uptake in the human organism on nutrition peculiarities is shown. Strontium-90 polluting vegetable products due to particle sorption from the air is less available for the uptake than 90 Sr resorbed from the soil with vegetation. Therefore, this nuclide is uptaken more completely from milk which containes 90 Sr in a soluble form than from grain and bakery products which are polluted by 90 Sr largely by air

Interim main report of the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

Hedin, Allan [and others

2004-08-01

This document is an interim report on the safety assessment SR-Can (SR in the acronym stands for Safety Report and Can is short for canister). The final SR-Can report will support SKB's application to build an Encapsulation plant for spent nuclear fuel and is to be produced in 2006. The purpose of the present interim report is to demonstrate the methodology for safety assessment so that it can be reviewed before it is used in a license application. The assessment relates to the KBS-3 disposal concept in which copper canisters with a cast iron insert containing spent nuclear fuel are surrounded by bentonite clay and deposited at approximately 500 m depth in saturated, granitic rock. Preliminary data from the Forsmark site, presently being investigated by SKB as one of the candidate for a KBS-3 repository are used to some extent as examples. However, the collected data are yet too sparse to allow an evaluation of safety for this site. An important aim of this report is to demonstrate the proper handling of requirements on the safety assessment in applicable regulations. Therefore, regulations issued by the Swedish Nuclear Power Inspectorate and the Swedish Radiation Protection Authority are duplicated in an Appendix. The principal acceptance criterion requires that 'the annual risk of harmful effects after closure does not exceed 10{sup -6} for a representative individual in the group exposed to the greatest risk'. 'Harmful effects' refer to cancer and hereditary effects. Following the introductory chapter 1, this report outlines the methodology for the SR-Can assessment in chapter 2, and presents in chapters 3, 4 and 5 the initial state of the system and the plans and methods for handling external influences and internal processes, respectively. Function indicators are introduced in chapter 6 and a preliminary evaluation of these is given in chapter 7. The material presented in the first seven chapters is utilised in the scenario selection in chapter 8

Interim main report of the safety assessment SR-Can

International Nuclear Information System (INIS)

Hedin, Allan

2004-08-01

This document is an interim report on the safety assessment SR-Can (SR in the acronym stands for Safety Report and Can is short for canister). The final SR-Can report will support SKB's application to build an Encapsulation plant for spent nuclear fuel and is to be produced in 2006. The purpose of the present interim report is to demonstrate the methodology for safety assessment so that it can be reviewed before it is used in a license application. The assessment relates to the KBS-3 disposal concept in which copper canisters with a cast iron insert containing spent nuclear fuel are surrounded by bentonite clay and deposited at approximately 500 m depth in saturated, granitic rock. Preliminary data from the Forsmark site, presently being investigated by SKB as one of the candidate for a KBS-3 repository are used to some extent as examples. However, the collected data are yet too sparse to allow an evaluation of safety for this site. An important aim of this report is to demonstrate the proper handling of requirements on the safety assessment in applicable regulations. Therefore, regulations issued by the Swedish Nuclear Power Inspectorate and the Swedish Radiation Protection Authority are duplicated in an Appendix. The principal acceptance criterion requires that 'the annual risk of harmful effects after closure does not exceed 10 -6 for a representative individual in the group exposed to the greatest risk'. 'Harmful effects' refer to cancer and hereditary effects. Following the introductory chapter 1, this report outlines the methodology for the SR-Can assessment in chapter 2, and presents in chapters 3, 4 and 5 the initial state of the system and the plans and methods for handling external influences and internal processes, respectively. Function indicators are introduced in chapter 6 and a preliminary evaluation of these is given in chapter 7. The material presented in the first seven chapters is utilised in the scenario selection in chapter 8. Hydrogeological

Decoupling of unpolluted temperate forests from rock nutrient sources revealed by natural 87Sr/86Sr and 84Sr tracer addition

Science.gov (United States)

Kennedy, Martin J.; Hedin, Lars O.; Derry, Louis A.

2002-01-01

An experimental tracer addition of 84Sr to an unpolluted temperate forest site in southern Chile, as well as the natural variation of 87Sr/86Sr within plants and soils, indicates that mechanisms in shallow soil organic horizons are of key importance for retaining and recycling atmospheric cation inputs at scales of decades or less. The dominant tree species Nothofagus nitida feeds nearly exclusively (>90%) on cations of atmospheric origin, despite strong variations in tree size and location in the forest landscape. Our results illustrate that (i) unpolluted temperate forests can become nutritionally decoupled from deeper weathering processes, virtually functioning as atmospherically fed ecosystems, and (ii) base cation turnover times are considerably more rapid than previously recognized in the plant available pool of soil. These results challenge the prevalent paradigm that plants largely feed on rock-derived cations and have important implications for understanding sensitivity of forests to air pollution. PMID:12119394

Foliar uptake of 134Cs and 85Sr in strawberry as function by leaf age

International Nuclear Information System (INIS)

Fortunati, P.; Brambilla, M.; Speroni, F.; Carini, F.

2004-01-01

In this paper a study of the foliar uptake and translocation of 134 Cs and 85 Sr in a herbaceous fruit plant is presented. In particular, absorption, translocation and loss of these radionuclides in strawberry plants have been studied in relation to the age of contaminated leaves. Strawberry plants were contaminated by distributing droplets of an aqueous solution containing 134 CsCl and 85 SrCl 2 on the surface of two leaves per plant. One half of the plants was contaminated through two young leaves, a second half through two old leaves. Sets of plants were collected 1 day, 7 days and 15 days after contamination. One half of them was rinsed with double distilled water before gamma analysis. Rinsing contaminated leaves removes on average 55% of the applied 134 Cs and 45% of 85 Sr. The activity removed decreases during the 15 days of the experimental study, both for 134 Cs and for 85 Sr, suggesting an increase in foliar absorption during this period. The activity removed does not differ between old and young leaves. 'External loss' is lower for young than old contaminated leaves. 'Internal loss' through translocation occurs mainly for 134 Cs. Translocation coefficients from contaminated leaves to fruits are two orders of magnitude higher for 134 Cs (4.0%), than for 85 Sr (0.05%). Leaf to fruit translocation coefficients for 134 Cs are higher from young leaves (5.8%), than from old leaves (2.3%)

Size exclusion chromatography for semipreparative scale separation of Au38(SR)24 and Au40(SR)24 and larger clusters.

Science.gov (United States)

Knoppe, Stefan; Boudon, Julien; Dolamic, Igor; Dass, Amala; Bürgi, Thomas

2011-07-01

Size exclusion chromatography (SEC) on a semipreparative scale (10 mg and more) was used to size-select ultrasmall gold nanoclusters (<2 nm) from polydisperse mixtures. In particular, the ubiquitous byproducts of the etching process toward Au(38)(SR)(24) (SR, thiolate) clusters were separated and gained in high monodispersity (based on mass spectrometry). The isolated fractions were characterized by UV-vis spectroscopy, MALDI mass spectrometry, HPLC, and electron microscopy. Most notably, the separation of Au(38)(SR)(24) and Au(40)(SR)(24) clusters is demonstrated.

Thermodynamic modeling of the Sr-Co-Fe-O system

DEFF Research Database (Denmark)

Zhang, Wei Wei; Povoden-Karadeniz, Erwin; Chen, Ming

2016-01-01

This paper reviews and assesses phase equilibria and thermodynamic properties of phases in the Sr-Co-Fe-O system, with a focus on oxides, especially the SrCo1 - xFexO3 - δ perovskite. In our work, the SrCo1 - xFexO3 - δ perovskite was modeled with a three-sublattice model, where the three...... sublattices correspond to the A, B and oxygen sites in an ABO3 perovskite, respectively. A number of other important ternary oxide phases in Sr-Co-O and Sr-Co-Fe-O were also considered. Available thermodynamic and phase diagram data were carefully assessed. A thermodynamic description of Sr-Co-O was derived...

The 87Sr/86Sr aquatic isoscape of the Danube catchment from the source to the mouth as tool for studying fish migrations

Science.gov (United States)

Zitek, Andreas; Tchaikovsky, Anastassiya; Irrgeher, Johanna; Waidbacher, Herwig; Prohaska, Thomas

2014-05-01

Isoscapes - spatially distributed isotope patterns across landscapes - are increasingly used as important basis for ecological studies. The natural variation of the isotopic abundances in a studied area bears the potential to be used as natural tracer for studying e.g. migrations of animals or prey-predator relations. The 87Sr/86Sr ratio is one important tracer, since it is known to provide a direct relation of biological samples to geologically distinct regions, as Sr isotopes are incorporated into living tissues as a proxy for calcium and taken up from the environment without any significant fractionation. Although until now the focus has been mainly set on terrestrial systems, maps for aquatic systems are increasingly being established. Here we present the first 87Sr/86Sr aquatic isoscape of the Danube catchment, the second largest river catchment in Europe, from near its source starting at river km 2581 in Germany down to its mouth to river km 107 in Romania. The total length of the river Danube is 2780 km draining a catchment area 801 463 km2 (10 % of the European continent). The major purpose of this study was to assess the potential of the 87Sr/86Sr isotope ratio to be used as tool for studying fish migrations at different scales in the entire Danube catchment. Within the Joint Danube Research 3 (JDS 3), the biggest scientific multi-disciplinary river expedition of the World in 2013 aiming at the assessment of the ecological status and degree of human alterations along the river Danube, water samples were taken at 68 pre-defined sites along the course of the river Danube including the major tributaries as a basis to create the so called 'Isoscape of the Danube catchment'. The determination of 87Sr/86Sr isotope ratio in river water was performed by multicollector-sector field-inductively coupled plasma-mass spectrometry (MC-SF-ICP-MS). The JDS 3 data were combined with existing data from prior studies conducted within the Austrian part of the Danube catchment

Rapid determination of 90Sr in seawater

International Nuclear Information System (INIS)

Pavlotskaya, F.I.; Moskin, A.I.

1994-01-01

A method for determining 90 Sr in seawater that is based on direct isolation and radiochemical purification of daughter 90 Y is proposed. The analysis time is 6-8 h. The chemical yield of the Y-carrier during the 90 Sr determination from 35 liters of seawater varies in the range 37-69%. The analysis uncertainty is 90 Sr from seawater and subsequent isolation of 90 Y

PRODUCTION OF PLANTARCIN BY LACTOBACILLUS PLANTARUM SR18

Directory of Open Access Journals (Sweden)

Wagih El-Shouny

2012-06-01

Full Text Available Out of 86 lactobacilli previously screened in our laboratory, Lactobacillus plantarum SR18 isolated from yoghurt revealed the largest detected inhibition zone against the selected indicator Streptococcus salivarius 5. The obtained electrophoretic patterns revealed that L. plantarum SR18 was free from plasmids. Exposure of 6 h growing L. plantarum culture to T-8M, 3B ultraviolet B lamp (8w, 220v & 312 nm for 2 h and subsequent growth for further 24 h resulted in an increase of cell-bound bacteriocin titer reached 2 fold at 12 h. Whereas bacteriocin secreted in the culture filtrate was not affected by UV irradiation. Plantarcin SR18 production was maximal (12800 AU/ml between 12 and 18 h by incubation of the culture at 37°C and pH 5-7 in candle jar (CO2. The bacteriocin bound to the cells and that secreted into the culture filtrate of L. plantarum SR18 were precipitated by 75% ammomium sulphate, dialysed and further purified by Gel filtration on Sephadex G-100. The specific activities (AU/mg protein were increased by a factor of about 5.3 and 2.35 for plantarcins purified from proteins bound to the cell of L. plantarum SR18 (plantarcin SR18 a and that secreted into the culture filtrate (plantarcin SR18 b, respectively. Gel filtration of plantarcin SR18a resulted in moderate antibacterial activity (3200 AU/ml and very high activity (25600 AU/ml of plantarcin SR18b.

90Sr and 89Sr in seawater off Japan as a consequence of the Fukushima Dai-ichi nuclear accident

Directory of Open Access Journals (Sweden)

N. Casacuberta

2013-06-01

Full Text Available The impact of the earthquake and tsunami on the east coast of Japan on 11 March 2011 caused a loss of power at the Fukushima Dai-ichi nuclear power plant (NPP that resulted in one of the most important releases of artificial radioactivity into the environment. Although several works were devoted to evaluating the atmospheric dispersion of radionuclides, the impact of the discharges to the ocean has been less investigated. Here we evaluate the distribution of Fukushima-derived 90Sr (n = 57 and 89Sr (n = 19 throughout waters 30–600 km offshore in June 2011. Concentrations of 90Sr and 89Sr in both surface waters and shallow profiles ranged from 0.8 ± 0.2 to 85 ± 3 Bq m−3 and from 19 ± 6 to 265 ± 74 Bq m−3, respectively. Because of its short half-life, all measured 89Sr was due to the accident, while the 90Sr concentrations can be compared to the background levels in the Pacific Ocean of about 1.2 Bq m−3. Fukushima-derived radiostrontium was mainly detected north of Kuroshio Current, as this was acting as a southern boundary for transport. The highest activities were associated with near-shore eddies, and larger inventories were found in the closest stations to Fukushima NPP. The data evidence a major influence of direct liquid discharges of radiostrontium compared to the atmospheric deposition. Existing 137Cs data reported from the same samples allowed us to establish a 90Sr / 137Cs ratio of 0.0256 ± 0.0006 in seawater off Fukushima, being significantly different than that of the global atmospheric fallout (i.e., 0.63 and may be used in future studies to track waters coming from the east coast of Japan. Liquid discharges of 90Sr to the ocean were estimated, resulting in an inventory of 53 ± 1 TBq of 90Sr in the inshore study area in June 2011 and total releases of 90Sr ranging from 90 to 900 TBq, depending upon the reported estimates of 137Cs releases that are considered.

Crystal structures of KM(AsF6)3 (M2+ = Mg, Co, Mn, Zn), KCu(SbF6)3 and [Co(HF)2]Sr[Sr(HF)]2-[Sr(HF)2]2[AsF6]12

International Nuclear Information System (INIS)

Mazej, Zoran; Goreshnik, Evgeny

2015-01-01

The KM(AsF 6 ) 3 (M 2+ = Mg, Co, Mn, Zn) and KCu(SbF 6 ) 3 compounds crystallize isotypically to previously known KNi(AsF 6 ) 3 . The main features of the structure of these compounds are rings of MF 6 octahedra sharing apexes with AsF 6 octahedra connected into infinite tri-dimensional frameworks. In this arrangement cavities are formed where K + cations are placed. Single crystals of CoSr 5 (AsF 6 ) 12 .8HF were obtained as one of the products after the crystallization of 3KF/CoF 2 /SrF 2 mixture in the presence of AsF 5 in anhydrous HF. The CoSr 5 (AsF 6 ) 12 .8HF is monoclinic, C/2c (No.15), with a = 26.773(5) Aa, b = 10.087(2) Aa, c = 21.141(5) Aa, β = 93.296(13) circle , V = 5699.9(19) Aa 3 at 200 K, and Z = 4. There are three crystallographically non-equivalent Sr 2+ cations in the crystal structure of CoSr 5 (AsF 6 ) 12 .8HF. The Sr1 is coordinated by ten fluorine atoms from eight different [AsF 6 ]- anions, meanwhile Sr2 and Sr3 are bound to nine fluorine atoms provided by one HF and eight AsF 6 units or by two HF and six AsF 6 units, respectively. The Co 2+ is coordinated distorted-octahedrally by six fluorine atoms from two HF molecules and four different AsF 6 units. All those moieties in the crystal structure of [Co(HF) 2 ]Sr[Sr(HF)] 2 [Sr(HF) 2 ] 2 [AsF 6 ] 12 are connected into tridimensional framework. The CoSr 5 (AsF 6 ) 12 .8HF is a unique example of compound where HF molecules are directly bound via fluorine atoms to two different metal centres.

Geographical distribution of 90Sr contamination in Poland

International Nuclear Information System (INIS)

Gaca, P.; Mietelski, J.W.; Skwarzec, B.

2006-01-01

The paper presents results on determination of 90 Sr in bilberry and cowberry leaves (Vaccinium myrtillus and Vaccinium vitis-idaea) and the use of these plants as bio-monitors of radiostrontium contamination in Poland. Radiostrontium was determined by mean of liquid scintillation spectrometry preceded by radiochemical separation using Sr-resin and 85 Sr tracer. The approximate map of 90 Sr contamination of Poland is presented. The activity ratio between 90 Sr and obtained earlier data for 137 Cs in the same samples is discussed. The enhancement of radiostrontium content observed in northeastern Poland seems to be the trace of hot-particles fallout from initial Chernobyl cloud, which passed over Polish territory toward Scandinavia. (orig.)

Studies on the leukemogenic and immunologic effects of radiostrontium (90Sr) and x rays in mice

International Nuclear Information System (INIS)

Ito, K.; Nagao, K.; Kawamura, Y.; Yokoro, K.

1976-01-01

The leukemogenic effect of internal irradiation with radiostrontium ( 90 Sr) was compared with that of external irradiation with x rays in ICR/JCL mice. Immunological, hematological, and cytogenetical changes were also studied during the preleukemic period in mice treated with 90 Sr or with x rays. A single intraperitoneal injection of 1.0 μCi of 90 Sr per gram of body weight resulted in leukemia in 62 percent of the mice. Only one of the 90 Sr-induced leukemias was of thymic origin. The occurrence of the leukemia was not affected by thymectomy. A fractionated whole-body x-irradiation of 680 R induced leukemia in 77 percent of the mice; the majority of the leukemias were of thymic origin. Although x-irradiation over the thymic region was ineffective in eliciting leukemia, a combined treatment of 90 Sr and local x-irradiation of the thymus was effective in inducing thymic lymphomas. The single intraperitoneal administration of 90 Sr caused an enhancement of both direct and indirect splenic plaque-forming cell (PFC) responses to sheep red blood cells, lasting for 35 days after treatment. No changes were observed in delayed-type hypersensitivity to picryl chloride. Thymectomy caused no appreciable effect in these immune responses. The fractionated whole-body x-irradiation rapidly depressed both PFC and delayed-type hypersensitivity responses, which persisted for a long period, especially in thymectomized mice. An abrupt increase of chromosomally aberrant cells in the thymus 60 days after the last x-irradiation was preceded by an increase of aberrant population in the bone marrow. On the other hand, a long-lasting appearance of aberrant population in the bone marrow and lymph nodes was observed in 90 Sr-injected mice

Contrasting pressure effects in Sr2VFeAsO3 and Sr2ScFePO3

International Nuclear Information System (INIS)

Kotegawa, Hisashi; Kawazoe, Takayuki; Tou, Hideki; Murata, Keizo; Ogino, Hiraku; Kishio, Kohji; Shimoyama, Jun-ichi

2009-01-01

We report the resistivity measurements under pressure of two Fe-based superconductors with a thick perovskite oxide layer, Sr 2 VFeAsO 3 and Sr 2 ScFePO 3 . The superconducting transition temperature T c of Sr 2 VFeAsO 3 markedly increases with increasing pressure. Its onset value, which was T c onset =36.4 K at ambient pressure, increases to T c onset =46.0 K at ∼4 GPa, ensuring the potential of the '21113' system as a high-T c material. However, the superconductivity of Sr 2 ScFePO 3 is strongly suppressed under pressure. The T c onset of ∼16 K decreases to ∼5 K at ∼4 GPa, and the zero-resistance state is almost lost. We discuss the factor that induces this contrasting pressure effect. (author)

Rb-Sr ages and initial 87Sr/86Sr ratios of late paleozoic granitic rocks from northern Chile

International Nuclear Information System (INIS)

Shibata, Ken; Ishihara, Shunso; Ulriksen, C.E.

1984-01-01

Rb-Sr whole-rock isochron ages were determined on three suites of so-called Paleozoic granitic rocks from northern coastal Chile. The granitic rocks from the Valparaiso and Ci Funcho areas are dated as 296.3 +- 5.4 Ma and 262.2 +- 4.6 Ma, respectively, which are in accord with geologically estimated age. The rocks from the Chanaral area is dated as 212.8 +- 8.6 Ma, which is correlated close to the Triassic-Jurassic boundary age. A K-Ar age of 196 +- 6 Ma was obtained on biotite in granite from Esmeralda between Ci Funcho and Chanaral. These age results demonstrate that no Precambrian plutonism occurred in the studied area, and that so-called Paleozoic granitic rocks in the Ci Funcho-Chanaral area are divided into Permian and early Mesozoic in age. Initial 87 Sr/ 86 Sr ratios of the ilmenite-series granitic rocks from the coastal region are 0.70641 (Valparaiso), 0.70635 (Ci Funcho) and 0.70455 (Chanaral). These relatively low ratios deny substantial crustal contribution to the granitoids. The initial ratios of magnetite-series granitoids from porphyry- and manto-type mineralized areas (Chiquicamata, El Salvador and Tocopilla) are as low as 0.70344 to 0.70464. (author)

87Sr/86Sr variations in basalts of Late Eocene-Early Miocene series in Eastern Sikhoteh-Alin

International Nuclear Information System (INIS)

Esin, S.V.; Ponomarchuk, V.A.; Shipitsyn, Yu.G.; Palesskij, Yu.G.

1993-01-01

Late Eocene high-alumina and Oligocene high-alumina and magnesian basalts of the Neogene calc-alkaline series from the Eastern Sikhoteh-Alin are shown to have the following 87 Sr/ 86 Sr ratios: 0.70390-0.70465; 0.70347-0.70401, and the 0.70330-0.70347. Analysis of variations of Sr ratios, REE, HFSE, and LILE suggests that they are the products of successive melting of a multicomponent source containing the peridotite material of OIB- and MORB-types altered by fluids to a different degree and the pelagic sediments

Phase equilibria in the system As2-O5 - SrO

International Nuclear Information System (INIS)

Kasenov, B.K.; Ashlyaeva, I.V.

1993-01-01

T-x phase state diagram of As 2 O 5 -SrO system was investigated by the methods of physicochemical analysis. It was established that incongruently melting Sr(AsO 3 ) 2 (t mel 900 deg C), Sr 2 As 2 O 4 (t mel = 1140 deg C), Sr 4 As 2 O 9 (t mel = 1390 deg C) and congruently melting at 1635 deg C Sr 3 (AsO 4 ) 2 formed in the system. Eutectic points were revealed in the system: As 2 O 5 -Sr(AsO 3 ) 2 (15.0 mol % SrO, 700 deg C) and Sr 3 (AsO 4 ) 2 -Sr 4 As 2 O 9 (78 mol % SrO, 1370 deg C)

Low Thermal Conductivity of RE-Doped SrO(SrTiO3)1 Ruddlesden Popper Phase Bulk Materials Prepared by Molten Salt Method

Science.gov (United States)

Putri, Yulia Eka; Said, Suhana Mohd; Refinel, Refinel; Ohtaki, Michitaka; Syukri, Syukri

2018-04-01

The SrO(SrTiO3)1 (Sr2TiO4) Ruddlesden Popper (RP) phase is a natural superlattice comprising of alternately stacking perovskite-type SrTiO3 layers and rock salt SrO layers along the crystallographic c direction. This paper discusses the properties of the Sr2TiO4 and (La, Sm)-doped Sr2TiO4 RP phase synthesized via molten salt method, within the context of thermoelectric applications. A good thermoelectric material requires high electrical conductivity, high Seebeck coefficient and low thermal conductivity. All three conditions have the potential to be fulfilled by the Sr2TiO4 RP phase, in particular, the superlattice structure allows a higher degree of phonon scattering hence resulting in lowered thermal conductivity. In this work, the Sr2TiO4 RP phase is doped with Sm and La respectively, which allows injection of charge carriers, modification of its electronic structure for improvement of the Seebeck coefficient, and most significantly, reduction of thermal conductivity. The particles with submicron size allows excessive phonon scattering along the boundaries, thus reduces the thermal conductivity by fourfold. In particular, the Sm-doped sample exhibited even lower lattice thermal conductivity, which is believed to be due to the mismatch in the ionic radius of Sr and Sm. This finding is useful as a strategy to reduce thermal conductivity of Sr2TiO4 RP phase materials as thermoelectric candidates, by employing dopants of differing ionic radius.

77 FR 24752 - Self-Regulatory Organizations; EDGA Exchange, Inc.; EDGX Exchange, Inc.; International Securities...

Science.gov (United States)

2012-04-25

... Securities Holdings, Inc. (``ISE Holdings'') to a newly formed Swiss corporation, Eurex Global Derivatives AG... SECURITIES AND EXCHANGE COMMISSION [Release No. 34-66834; File Nos. SR-EDGA-2012-08; SR-EDGX-2012....; International Securities Exchange, LLC; Order Granting Approval of Proposed Rule Change Relating to a Corporate...

Preparation of highly stable zeolite-alginate foam composite for strontium(90Sr) removal from seawater and evaluation of Sr adsorption performance.

Science.gov (United States)

Hong, Hye-Jin; Kim, Byoung-Gyu; Ryu, Jungho; Park, In-Su; Chung, Kang-Sup; Lee, Sang Moon; Lee, Jin-Bae; Jeong, Hyeon Su; Kim, Hyunchul; Ryu, Taegong

2018-01-01

Alginate bead is a promising strontium (Sr) adsorbent in seawater, but highly concentrated Na ions caused over-swelling and damaged the hydrogel bead. To improve the mechanical stability of alginate bead, flexible foam-type zeolite-alginate composite was synthesized and Sr adsorption performance was evaluated in seawater; 1-10% zeolite immobilized alginate foams were prepared by freeze-dry technique. Immobilization of zeolite into alginate foam converted macro-pores to meso-pores which lead to more compact structure. It resulted in less swollen composite in seawater medium and exhibited highly improved mechanical stability compared with alginate bead. Besides, Sr adsorption efficiency and selectivity were enhanced by immobilization of zeolite in alginate foam due to the increase of Sr binding sites (zeolite). In particular, Sr selectivity against Na was highly improved. The 10% zeolite-alginate foam exhibited a higher log K d of 3.3, while the pure alginate foam exhibited 2.7 in the presence of 0.1 M Na. Finally, in the real seawater, the 10% zeolite-alginate foam exhibited 1.5 times higher Sr adsorption efficiency than the pure alginate foam. This result reveals that zeolite-alginate foam composite is appropriate material for Sr removal in seawater due to its swelling resistance as well as improved Sr adsorption performance in complex media. Copyright © 2017 Elsevier Ltd. All rights reserved.

Geographical traceability based on 87Sr/86Sr indicator: a first approach for PDO Lambrusco wines from Modena.

Science.gov (United States)

Durante, Caterina; Baschieri, Carlo; Bertacchini, Lucia; Cocchi, Marina; Sighinolfi, Simona; Silvestri, Michele; Marchetti, Andrea

2013-12-01

The main goal of this study was to evaluate (87)Sr/(86)Sr ratio in different matrices, namely soils, branches, and grape juices, of an oenological food chain in order to develop a robust analytical strategy able to link the investigated food to its territory of origin. The (87)Sr/(86)Sr has been used as traceability marker and several aspects, affected its variability, i.e. geological features of the investigated area, the bio-available fraction of elements in the soils and the up-take of the plant, have been taken into account. Optimisation of an analytical procedure for the separation of Sr from its interferences and investigation of the analytical performances in terms of precision of used methodology have been carried out as well. This work highlighted a good match between the isotopic values monitored in the bio-available fraction of soils and their respective grape juices for almost all the investigated areas. The correlation with food satisfyingly improves when isotopic relative abundance values of branches vine are considered. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of 90Sr, adult thymectomy and antilymphocyteglobulin on haematopoietic tissues and peripheral blood leucocytes in CBA mice

International Nuclear Information System (INIS)

Bierke, P.

1986-01-01

The role or long-time immune suppression in carcinogenesis induced by the long-lived internal emitter 90 Sr, is investigated in an ongoing study. The experimental design is based on the assumption that impaired immune responsiveness, by other means than 90 Sr, might increase the neoplastic response in exposed individuals, and thus reflect a protective function, if existing. Intercomparison is made of the tumour yield in mice exposed to different single doses of 90 Sr and simultaneously subjected or not to long-term immune suppression by adult thymectomy (ATx) and/or antilymphocyteglobulin (ALG) treatment. Information on the general condition and responsiveness of the immune system, in the respective models, during tumour expectancy time, is essential for a conclusive evaluation of the results. To meet theses demands the present paper reports on histopathologic alternations in immune organs and changes in white blood cell counts, induced by the different combinations of 90 Sr, ATx + ALG treatment. The results confirm the prediction, that ATx + ALG is an efficient and, with respect to the purpose of the study, suitable treatment for additive long-term depression of the immune system in 90 Sr irradiated mice, evidenced in particular by increased depletion of monomorphonuclear cells (MNC) in lymphoid organs and peripheral blood. Subsequent reports will deal with functional immune parameters. (orig.)

Determination of 90Sr and 210Pb in freshwater fish in Austria

International Nuclear Information System (INIS)

Claudia Landstetter; Merita Sinojmeri; Christian Katzlberger; Arno Achatz

2014-01-01

A method for the determination of 90 Sr and 210 Pb in freshwater fish was developed. The determinations were conducted within a project on behalf of the Federal Ministry of Health. The aim of this project was to get an overview of the activity concentrations of natural and artificial radionuclides in freshwater fish in different lakes in Austria. For sampling the Neusiedler See in Burgenland, two lakes in Styria the Grundlsee and the Toplitz See, and the Zeller See in Salzburg were chosen. Chub (Leuciscus cephalus), pike (Esox lucius), perch (Perca fluviatilis), carp (Cyprinus carpio), catfish (Silurus glanis), pike-perch (Sander lucioperca) and burbot (Lota lota) were analysed. The samples were analysed using strontium specific extraction columns (Eichrom Industries Inc., TrisKem International) and liquid scintillation counting. In the edible parts of the fish samples (no fishbone) values of the activity concentration for 210 Pb varied between 0.009 ± 0.003 and 0.16 ± 0.04 Bq kg freshweight -1 and for 90 Sr between 0.010 ± 0.002 and 0.11 ± 0.02 Bq kg freshweight -1 . In this paper the method for the determination of 90 Sr and 210 Pb is described and the results are discussed. (author)

The effect of secondary apatite on the initial 87Sr/86Sr ratio determination in granitic rocks: a case study of the Tadamigawa pluton, northeastern Japan

Science.gov (United States)

Wakasugi, Y.; Ichino, K.; Tanioka, Y.; Wakaki, S.; Tsuboi, M.; Ishikawa, T.

2017-12-01

Apatite is a major accessory mineral in igneous rocks. Because Rb contents in apatite are very low, 87Sr/86Sr ratios of magmatic apatite are useful to estimate the initial 87Sr/86Sr ratio (SrI) of igneous rocks. Secondary post-magmatic event such as hydrothermal alteration may also crystallize secondary apatite, which may inhibit the estimation of SrI of igneous rocks. In this study, we examine the effects of secondary apatite on the initial 87Sr/86Sr ratio determination of granitic rocks by using acid leaching technique. Leached apatite samples were first separated from the whole rock powder as a heavy mineral fraction by heavy liquid technique, and the heavy mineral fraction was then leached by 3 M HNO3. The isotopic ratios of Sr and the concentrations of Rb and Sr were analyzed by TIMS and ICP-MS at Kochi Core Center, respectively. The Tadamigawa Older-stage granites, which locate in the Taishaku Mountains at the northeastern part of Japan, intrude into the Ashio Jurassic complex, and the ages of these rocks are late Cretaceous to Paleogene. The U-Pb ages of zircon and the K-Ar ages of biotite for these rocks are c. 100 Ma [1, 2]. Rb-Sr whole-rock isochron age of the pluton is 96.5 ± 1.3 Ma (SrI = 0.70534 ± 0.00003) and it is concordant with other radiometric ages. Rb-Sr mineral isochron ages range from 84.4 to 97.3 Ma and these ages are relatively younger than the Rb-Sr whole-rock isochron age. The difference among radiometric ages may reflect the difference of the closure temperature in each isotopic system. The Tadamigawa Older-stage granites have SrI for Rb-Sr mineral isochron range from 0.7053 to 0.7061 and are very similar to that (0.70534) for Rb-Sr whole-rock isochron. These may suggest that the Tadamigawa Older-stage granites are generated from same parental magma. However, 87Sr/86Sr ratios of the leached apatite samples were 0.70544-0.70856 and are relatively higher than SrI obtained from the Rb-Sr mineral isochrons (0.7053-0.7061). This result

A method for determination of 90Sr in vegetation

International Nuclear Information System (INIS)

Nygren, U.

1998-12-01

This report describes a method for determination of 90 Sr in vegetation. The method consists of wet-ashing the samples and separating Sr from the sample matrix by oxalate precipitation and extraction chromatography. 90 Y ingrowth is awaited after which Y is separated from Sr and 90 Y measured in a proportional counter. The method has been applied on two reference materials and the 90 Sr results agree well with the recommended values. The method has also been used on 20 samples of blueberry twigs and the mean recovery of Sr was 74%

Migration and distribution of 90Sr in soil

International Nuclear Information System (INIS)

Yang Juncheng; Zhu Yongyi; Chen Jingjian

1993-01-01

The migration and distribution of radionuclide 90 Sr were conducted by the analysis of 97 soil longitudinal sections under natural conditions and by pot experiments with fallout and 90 Sr solution, respectively. Spring wheat and rice were employed in the pot experiments. The result showed that the radionuclide 90 Sr was mainly accumulated in the topsoil 0-10 cm under both of the natural and laboratory conditions. The vertical distribution of 90 Sr in soil agreed with the power function, which obtained was Y = 75.78 X -0.527 ; r = -0.986; n = 97. The existing forms of 90 Sr from fallout in soil, only 0.02-0.03% was in a soluble form and 0.06-0.07% in non-replaceable form

OpenNebula KVM SR-IOV driver

CSIR Research Space (South Africa)

Macleod, D

2013-05-01

Full Text Available With the recent release of an OFED which supports SR-IOV on Infiniband HCAs it is now possible to use verbs from inside a VM. This VMM driver supports these Infiniband HCAs, and any other SR-IOV network device, in OpenNebula....

Abscisic Acid (ABA) Regulation of Arabidopsis SR Protein Gene Expression

Science.gov (United States)

Cruz, Tiago M. D.; Carvalho, Raquel F.; Richardson, Dale N.; Duque, Paula

2014-01-01

Serine/arginine-rich (SR) proteins are major modulators of alternative splicing, a key generator of proteomic diversity and flexible means of regulating gene expression likely to be crucial in plant environmental responses. Indeed, mounting evidence implicates splicing factors in signal transduction of the abscisic acid (ABA) phytohormone, which plays pivotal roles in the response to various abiotic stresses. Using real-time RT-qPCR, we analyzed total steady-state transcript levels of the 18 SR and two SR-like genes from Arabidopsis thaliana in seedlings treated with ABA and in genetic backgrounds with altered expression of the ABA-biosynthesis ABA2 and the ABA-signaling ABI1 and ABI4 genes. We also searched for ABA-responsive cis elements in the upstream regions of the 20 genes. We found that members of the plant-specific SC35-Like (SCL) Arabidopsis SR protein subfamily are distinctively responsive to exogenous ABA, while the expression of seven SR and SR-related genes is affected by alterations in key components of the ABA pathway. Finally, despite pervasiveness of established ABA-responsive promoter elements in Arabidopsis SR and SR-like genes, their expression is likely governed by additional, yet unidentified cis-acting elements. Overall, this study pinpoints SR34, SR34b, SCL30a, SCL28, SCL33, RS40, SR45 and SR45a as promising candidates for involvement in ABA-mediated stress responses. PMID:25268622

SR-71 Pilot Stephen (Steve) D. Ishmael

Science.gov (United States)

1992-01-01

NASA research pilot Stephen D. Ishmael is pictured here in front of an SR-71 Blackbird on the ramp at the Dryden Flight Research Center, Edwards, California. Ishmael was one of two NASA research pilots assigned to the SR-71 high speed research program in the early 1990s at NASA's Dryden Flight Research Facility (redesignated the Dryden Flight Research Center in 1994), Edwards, California. Ishmael became a NASA research pilot in 1977. Data from the SR-71 program will be used to aid designers of future supersonic aircraft and propulsion systems. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and

(Ba+Sr)/Ti ratio dependence of the dielectric properties for (Ba0.5Sr0.5)TiO3 thin films prepared by ion beam sputtering

Science.gov (United States)

Yamamichi, Shintaro; Yabuta, Hisato; Sakuma, Toshiyuki; Miyasaka, Yoichi

1994-03-01

(Ba0.5Sr0.5)TiO3 thin films were prepared by ion beam sputtering from powder targets with (Ba+Sr)/Ti ratios ranging from 0.80 to 1.50. All of the perovskite (Ba,Sr)TiO3 films were single phase except for the film with a (Ba+Sr)/Ti ratio of 1.41. The dielectric constant values notably depended on the (Ba+Sr)/Ti ratio for films thicker than 70 nm. The highest dielectric constant of 580 was achieved for the 5% (Ba+Sr) rich film. This (Ba+Sr)/Ti ratio dependence was diminished by the thickness dependence for thinner films. The grain sizes for the 9% (Ba+Sr) rich film and for the 6% (Ba+Sr) poor film ranged from 70 to 100 nm and from 30 to 60 nm, respectively. This grain size difference could explain why slightly A-site rich (Ba,Sr)TiO3 films have a larger dielectric constant than A-site poor films.

Sr and Nd isotope systematics in fish teeth

International Nuclear Information System (INIS)

Staudigel, H.; Zindler, A.

1985-01-01

High concentrations of Sr and Nd in fish teeth apatite (up to 2000 and 3800 ppm, respectively) make them relatively impervious to diagenetic overprints and allow high-precision analysis of 87 Sr/ 86 Sr and 143 Nd/ 144 Nd of very small amounts of material. 87 Sr/ 86 Sr ratios of 14 Cenozoic samples ( 87 Sr/ 86 Sr stratigraphic dating. A compilation of published 143 Nd/ 144 Nd data from recent Mn-nodules and marine Fe/Mn deposits shows that the North-Central Pacific Ocean and the major portion of the Atlantic Ocean display distinctly different, narrow ranges in isotopic compositions. Between these two areas, the 143 Nd/ 144 Nd of Mn-nodules vary systematically towards intermediate compositions in the Southern Oceans, reflecting the communication between the Atlantic and Pacific Oceans through the eastward moving Antarctic Circumpolar Current. The 143 Nd/ 144 Nd of the 2-55 Ma old fish teeth analyzed are typically close to the range of 143 Nd/ 144 Nd in Recent Mn-nodules and seawater for the respective ocean and, thus, indicate no significant change through this time period. The 143 Nd/ 144 Nd of fish teeth from the North Pacific Ocean are highest during periods of high aeolian sedimentation. (orig.)

Tracing sediment sources in upstream agricultural catchments: contribution of elemental geochemistry, 87Sr/86Sr ratio and radionuclides measurements

International Nuclear Information System (INIS)

Le-Gall, Marion

2016-01-01

Soil erosion is recognized as one of the main processes of land degradation in agricultural environments. This study develops an original fingerprinting method to examine sediment source contributions in two contrasted agricultural catchments. Several properties were used to trace sediment lithological sources ( 87 Sr/ 86 Sr ratios, elemental concentrations), soil surface and subsurface sources ( 137 Cs) and to quantify their temporal dynamics ( 7 Be, 210 Pb xs ). In the Louroux catchment (24 km 2 , France), representative of drained areas of Northwestern Europe, results showed the dominant contribution of very fine particles (≤2 μm) transiting through the tile drainage system to suspended sediment. Sediment accumulated in the river channel was mainly exported during the two first floods investigated in 2013 whereas the next event was characterized by the transport of sediment eroded from the cultivated soil surface. Mixing models were used, and results indicated that surface sources contributed the majority of sediment deposited in the pond, at the outlet of the catchment. The two lithological sources, discriminated using 87 Sr/ 86 Sr ratios, contributed in similar proportions to downstream pond sediment. In contrast, significant variations were observed since the 1950's. These changes may be related to the progressive implementation of land consolidation schemes within the catchment. Results obtained in the Louroux catchment revealed the potential of 87 Sr/ 86 Sr ratios to trace sediment lithological sources. The methodology was then applied to the larger and steeper Guapore catchment (2000 km 2 , Brazil), exposed to a more erosive climate and characterized by contrasted laterite soils. 87 Sr/ 86 Sr ratios and elements that discriminated the five soil types found in the catchment were incorporated in mixing models. Results showed that the major part of sediment was supplied by soils located in lower catchment parts. This result suggests the higher

Kinetics of distribution of 90Sr in Beijing-white layers

International Nuclear Information System (INIS)

Shang Zhaorong; Xu Shiming; Zhao Wenhu; Hou Lanxin

1993-08-01

The experiment feeding 90 Sr(NO 3 ) 2 in the range of 1.85 x 10 2 to 1.85 x 10 5 Bq/chicken was carried out with 45 Beijing-white layers to observe the regular pattern of absorption and distribution of 90 Sr in organs and tissues. The results are summarized as follows: the uptake rate of 90 Sr by layer through oral feeding is very low. Most part of 90 Sr drains away from body with daily excreta and egg. The accumulation of 90 Sr in the body is low and about 70% is in the bone. About 99% of 90 Sr in egg is concentrated in the eggshell. The order of absorptivity of 90 Sr in tissues is bone>feather>muscle>blood>viscera. The absorption coefficient of 90 Sr in organs and tissues in different stages with different feeding volumes has been calculated

The accumulation and elimination of 89Sr in tea leaves

International Nuclear Information System (INIS)

Zhang Yongxi; Wang Shouxiang; Chen Chuanqun; Sun Zhiming; Hu Bingmin; Huang Dan

1995-01-01

The 89 Sr was added to the tea tree-soil system by different ways. The 89 Sr in the system through the over-ground part of tea tree, was much more than that through soil. The 89 Sr concentration in older leaves was higher than in shoot for a definite treatment. The accumulation elimination law of 89 Sr in leaves varied with the treatments. For the treatment through the over-ground part, the 89 Sr concentration in older leaves and shoot was monotonously decreased with time increasing. But for the treatment through soil the 89 Sr concentration in shoot was increased to reach a peak value, and then decreased slowly; while the 89 Sr concentration in older leaves increased quickly in a period, then increased slowly to attain a saturated value. In addition, the concentration factor of 89 Sr in older leaves and shoot were determined

Igneous Consequence Modeling for the TSPA-SR

International Nuclear Information System (INIS)

McCord, John

2001-01-01

The purpose of this technical report is to develop credible, defendable, substantiated models for the consequences of igneous activity for the TSPA-SR Model. The effort will build on the TSPA-VA and improve the quality of scenarios and depth of the technical basis underlying disruptive events modeling. Computational models for both volcanic eruptive releases (this is an event that results in ash containing waste being ejected from Yucca Mountain) and igneous intrusion groundwater releases (this is an event that reaches the repository level, impacts the waste packages, and produces releases from waste packages damaged by igneous activity) will be included directly in the TSPA calculations as part of the TSPA-SR Model. This Analysis Model Report (AMR) is limited to development of the conceptual models for these two scenarios. The mathematical implementation of these conceptual models will be done within the TSPA-SR Model. Thus, this AMR will not include any model results or sensitivity analyses. Calculation of any doses resulting from igneous releases will also be done within the TSPA-SR model, as will the probabilistic weighting of these doses. Calculation and analysis of the TSPA-SR Model results for igneous disruption are, therefore, outside the scope of this activity. The reason for not running the mathematical models as part of this AMR is that the models are integrated within the TSPA-SR model and, thus, any model simulations and the corresponding results are out of the scope of this AMR. The scope of this work as defined in the development plan (CRWMS M and O 2000j) involves using data that has been extracted from existing sources to design and support the TSPA-SR models for the transport of radionuclides following igneous disruption of the repository. The development plan states ''applications of the code in this analysis will be limited to testing of the code and sensitivity analyses during analysis design.'' In contrast to the development plan, the ASHPLUME

Separation of 90Sr from Purex high level waste and development of a 90Sr-90Y generator

International Nuclear Information System (INIS)

Ramanujam, A.; Dhami, P.S.; Chitnis, R.R.; Achuthan, P.V.; Kannan, R.; Gopalakrishnan, V.; Balu, K.

2000-04-01

90 Y (T 1/2 =64.2 h) finds several applications in nuclear medicine. It is formed from the decay of 90 Sr which has a long half-life of 28.8 years. 90 Sr can be used as a long-lasting source for the production of carrier-free 90 Y. 90 Sr itself is abundantly available in high level waste (HLW) of PUREX origin. The present studies deal with the separation of pure 90 Sr from HLW and the subsequent separation of 90 Y from 90 Sr. Actinides and some of the fission products like lanthanides, zirconium, molybdenum and cesium were first removed from the HLW using methods based on solvent extraction and ion-exchange studied earlier in our laboratory. The resulting waste solution was used as a feed for the present process. The separation of 90 Sr from HLW was based on radiochemical method which involved a repeated scavenging with ferric hydroxide followed by strontium carbonate precipitation. The separation of 90 Y from 90 Sr was achieved by membrane separation technique. A compact generator is developed for this separation using a commercially available polytetrafluoroethylene (PTFE) membrane, impregnated with indigenously synthesised 2-ethylhexyl 2-ethylhexyl phosphonic acid (KSM-17). Generator system overcomes the drawbacks associated with conventional solvent extraction and ion-exchange based generators. The product is in chloride form and is suitable for complexation studies. After gaining an operating experience of ∼3 years in generating carrier-free 90 Y at 2 mCi level for initial studies in radiotherapeutic applications, the process was scaled up for the production of about 12 mCi of 90 Y to be used for animal studies before its application to patients. Radiochemical and chemical purity of the product was critically assayed by radiometry, ICP-AES, etc. The process is amenable for further scaling up. (author)

Comparative study of potentially J{sub eff} = 0 ground state iridium(V) in SrLaNiIrO{sub 6}, SrLaMgIrO{sub 6}, and SrLaZnIrO{sub 6}

Energy Technology Data Exchange (ETDEWEB)

Wolff, Klaus K.; Agrestini, Stefano; Tjeng, Liu Hao [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany); Tanaka, Arata [Department of Quantum Matter, AdSM, Hiroshima University, Higashi-Hiroshima (Japan); Jansen, Martin [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany); Max Planck Institute for Solid State Research, Stuttgart (Germany)

2017-12-13

A series of polycrystalline double perovskites SrLaBIrO{sub 6} (B = Ni, Mg, Zn) containing Ir{sup 5+} (5d{sup 4}) was synthesized by solid state reactions, and structural, magnetic and electronic properties were investigated. The isotypic fully ordered double perovskites crystallize in space group P2{sub 1}/n and show semiconducting behavior with estimated bandgaps of approximately 0.2 eV for SrLaNiIrO{sub 6} and SrLaZnIrO{sub 6}, and 0.4 eV for SrLaMgIrO{sub 6}. SrLaNiIrO{sub 6} is an antiferromagnet with a Neel temperature of 74 K (μ{sub eff} = 3.3 μ{sub B}, θ{sub W} = -90 K), whereas SrLaMgIrO{sub 6} and SrLaZnIrO{sub 6} are weakly paramagnetic. All title compounds exhibit a temperature-independent contribution to the measured magnetic susceptibility, which supports the notion for a van-Vleck-type response originating from the Ir{sup 5+} (5d{sup 4}, J{sub eff} = 0) ions. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

System of Sr(NO sub 2 ) sub 2 -Sr(OH) sub 2 -H sub 2 O at 25 deg C. Sistema Sr(NO sub 2 ) sub 2 -H sub 2 O pri 25 grad C

Energy Technology Data Exchange (ETDEWEB)

Popova, T B; Berdyukova, V A; Khutsistova, F M [Kalmytskij Gosudarstvennyj Univ., Ehlista (USSR) Rostovskij-na-Donu Gosudarstvennyj Univ., Rostov-na-Donu (USSR)

1990-02-01

Sr(NO{sub 2}){sub 2}-Sr(OH){sub 2}-H{sub 2}O system was investigated by the methods of solubility, density, viscosity, electric conductivity and refractometry. It was established that its compoments form the compound 4Sr(NO{sub 2}){sub 2}xSr(OH){sub 2}x8H{sub 2}O. The compound was separated from solution; its density, decomposition temperature were determined; IR spectra and X-ray patterns of prepared and initial compounds were obtained.

ELNES study of chemical solution deposited SrO(SrTiO3)n Ruddlesden-Popper films: Experiment and simulation

International Nuclear Information System (INIS)

Riedl, T.; Gemming, T.; Weissbach, T.; Seifert, G.; Gutmann, E.; Zschornak, M.; Meyer, D.C.; Gemming, S.

2009-01-01

This article analyzes electron energy-loss near-edge fine structures of the SrO(SrTiO 3 ) n=1 Ruddlesden-Popper system and of the parent compounds SrTiO 3 and SrO by comparison with first principles calculations. For that, the fine structures of chemical solution deposited Ruddlesden-Popper films have been experimentally recorded by means of transmission electron microscopy. Moreover, density of states computations using an all-electron density-functional code have been performed. It is shown that the appearance and shape of the experimental O-K and Ti-L 2,3 fine structure features result from the crystallography-dependent electronic structure of the investigated oxides, which display technologically interesting dielectric as well as lattice-structural properties.

Isotopic compositions of Sr in waters and of Pb in sediments and ashes from an urban incinerator using an ICP-MS

International Nuclear Information System (INIS)

Fillion, N.; Clauer, N.; Samuen, J.

1996-01-01

The analytical precision of the Sr and the Pb isotopic compositions of natural samples obtained with a conventional ICP-MS is of 3 to 7 x 10 -3 (internal 2 σ) for the 87 Sr/ 86 Sr ratio, 6 to 8 x 10 -3 for the 206 Pb/ 207 Pb and 1 to 4 x 10 -1 for the 206 Pb/ 204 Pb and 207 Pb/ 204 Pb ratios. Such accuracy is obtained with a procedure including a resin-chromatographic purification, a correction with respect to standard values (NBS 987 and 981) and a routine of four determinations for each sample. This procedure should allow rapid geochemical investigations ahead of more precise determinations by thermo-ionization mass spectrometry. (authors). 8 refs., 6 figs., 5 tabs

Interim main report of the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

Hedin, Allan (ed.) [and others

2004-08-01

This document is an interim report on the safety assessment SR-Can (SR in the acronym stands for Safety Report and Can is short for canister). The final SR-Can report will support SKB's application to build an Encapsulation plant for spent nuclear fuel and is to be produced in 2006. The purpose of the present interim report is to demonstrate the methodology for safety assessment so that it can be reviewed before it is used in a license application. The assessment relates to the KBS-3 disposal concept in which copper canisters with a cast iron insert containing spent nuclear fuel are surrounded by bentonite clay and deposited at approximately 500 m depth in saturated, granitic rock. Preliminary data from the Forsmark site, presently being investigated by SKB as one of the candidate for a KBS-3 repository are used to some extent as examples. However, the collected data are yet too sparse to allow an evaluation of safety for this site. An important aim of this report is to demonstrate the proper handling of requirements on the safety assessment in applicable regulations. Therefore, regulations issued by the Swedish Nuclear Power Inspectorate and the Swedish Radiation Protection Authority are duplicated in an Appendix. The principal acceptance criterion requires that 'the annual risk of harmful effects after closure does not exceed 10{sup -6} for a representative individual in the group exposed to the greatest risk'. 'Harmful effects' refer to cancer and hereditary effects. Following the introductory chapter 1, this report outlines the methodology for the SR-Can assessment in chapter 2, and presents in chapters 3, 4 and 5 the initial state of the system and the plans and methods for handling external influences and internal processes, respectively. Function indicators are introduced in chapter 6 and a preliminary evaluation of these is given in chapter 7. The material presented in the first seven chapters is utilised in the scenario selection

Development of 90Sr-90Y generators

International Nuclear Information System (INIS)

Barrio, Graciela

2007-01-01

Yttrium-90 is a radioisotope of great interest in the field of Nuclear Medicine. It is considered one of the most important and most used radionuclides for radioimmunotherapeutical applications, especially promising for the treatment of certain types of cancer. Another important application of 90 Y is radio synovectomy. This radionuclide has a half-life of 64 hours, emits long range beta particles (maximum energy of 2.3 MeV) and decays, without intermediate nuclides, to a stable daughter. 90 Y may be obtained carrier-free, generated by the decay of its parent 90 Sr (half-life=28 years). 90 Sr is a product from uranium fission, and due to its long half-life, can be indefinitely used, which is certainly advantageous. It is present in great amounts, and needs to be processed and purified in order to be used as raw material for the generators. Generators of 90 Sr- 90 Y may thus be used during various months, due to 90 Sr long half-life. Several methods for the separation of 90 Y from 90 Sr by solvent extraction and ion exchange have been reported in literature. Thanks to its simplicity, ion exchange techniques have been more commonly used for this generator system. The main objective of this work was to develop a methodology for the preparation of 90 Sr- 90 Y generators, using cationic exchange resins. In such method, 90 Sr is strongly adsorbed in the resin and 90 Y is eluted by a 0.003 M EDTA solution. According to the quality control carried out, results showed that elution yields are greater than 65%, thus confirming the efficiency of the separation method used.

Possible two-stage 87Sr evolution in the Stockdale Rhyolite

International Nuclear Information System (INIS)

Compston, W.; McDougall, I.; Wyborn, D.

1982-01-01

The Rb-Sr total-rock data for the Stockdale Rhyolite, of significance for the Palaeozoic time scale, are more scattered about a single-stage isochron than expected from experimental error. Two-stage 87 Sr evolution for several of the samples is explored to explain this, as an alternative to variation in the initial 87 Sr/ 86 Sr which is customarily used in single-stage dating models. The deletion of certain samples having very high Rb/Sr removes most of the excess scatter and leads to an estimate of 430 +- 7 m.y. for the age of extrusion. There is a younger alignment of Rb-Sr data within each sampling site at 412 +- 7 m.y. We suggest that the Stockdale Rhyolite is at least 430 m.y. old, that its original range in Rb/Sr was smaller than now observed, and that it experienced a net loss in Sr during later hydrothermal alteration at ca. 412 m.y. (orig.)

Determination of the electrostatic potential distribution in Pt/Fe:SrTiO3/Nb:SrTiO3 thin-film structures by electron holography

Science.gov (United States)

Marchewka, Astrid; Cooper, David; Lenser, Christian; Menzel, Stephan; Du, Hongchu; Dittmann, Regina; Dunin-Borkowski, Rafal E.; Waser, Rainer

2014-11-01

We determined the electrostatic potential distribution in pristine Pt/Fe:SrTiO3/Nb:SrTiO3 structures by electron holography experiments, revealing the existence of a depletion layer extending into the Nb-doped bottom electrode. Simulations of potential profiles in metal-insulator-metal structures were conducted assuming different types and distributions of dopants. It is found that the presence of acceptor-type dopant concentrations at the Fe:SrTiO3/Nb:SrTiO3 interface with a donor-doped insulating layer provides a good match to the measured profile. Such acceptor-type interface concentrations may be associated with Sr vacancies on the Nb:SrTiO3 side of the bottom interface.

Assessing Covariation of Holocene Monsoon Intensity and Local Moisture Conditions in Eastern and Southwestern Amazon Basin Using Speleothem δ18O and 87Sr/86Sr Values

Science.gov (United States)

Ward, B. M.; Wong, C. I.; Novello, V. F.; Silva, L.; McGee, D.; Cheng, H.; Wang, X.; Edwards, R. L.; Cruz, F. W., Sr.; Santos, R. V.

2017-12-01

δ18O records from South America offer insight into past variability of the South American Monsoon System (SAMS). Potential, however, for understanding local moisture conditions is limited as precipitation δ18O is strongly influenced by regional climate dynamics. Here we create Holocene speleothem 87Sr/86Sr records at 200-yr resolution using TIMS methods in the Center for Isotope Geochemistry at Boston College to complement existing Holocene δ18O speleothem records and investigate local moisture conditions above caves located in the eastern Amazon Basin (PAR - 4°S, 55°W) and southwestern Brazil (JAR - 21°S, 56°W). Speleothem 87Sr/86Sr variability is interpreted to reflect differences in the extent of water-rock interaction due to differences in infiltration rates under wet and dry conditions. Drier conditions promote longer residence time, enhanced water-rock interaction, and greater evolution of dripwater 87Sr/86Sr values from an initial isotopic signature acquired from the soil to the signature of the cave host rock. PAR speleothem 87Sr/86Sr values range from 0.71024 to 0.71067 and are bracketed by soil (0.71710 to 0.70956) and bedrock (0.70852 to 0.70899) values. JAR speleothem 87Sr/86Sr values range from 0.71216 to 0.71539 and are greater than bedrock values (0.70825 to 0.71219), although some speleothem values exceed the single analysis conducted of the soil isotopic composition (0.71473). JAR speleothem 87Sr/86Sr values increase from the early to mid Holocene, consistent with increase in local moisture availability associated with intensification of the SAMS suggested by decreasing δ18O values in many records from the region. Speleothem 87Sr/86Sr values at JAR decrease from the mid to late Holocene, consistent with an increase in δ18O values at PAR that suggest a decline in monsoon intensity. 87Sr/86Sr variability at JAR, however, is positively correlated with the δ18O record. Preliminary 87Sr/86Sr results from PAR are only broadly consistent with

Dosimetry of Sr-90 ophthalmic applicators

International Nuclear Information System (INIS)

Reft, C.S.; Kuchnir, F.T.; Rosenberg, I.; Myrianthopoulos, L.C.

1990-01-01

Sr-90 ophthalmic applicators are commonly used for the treatment of superficial eye disorders. Although a variety of dosimetric devices such as film, thermoluminescent dosimeters (TLD's), ion chambers, and radiochromic foils have been used to measure the peak dose at the applicator surface, there is no internationally agreed upon calibration procedure. Recently, large discrepancies among calibrations of the same applicator at three institutions have been reported. Here we describe a technique to obtain the peak dose rate at the applicator surface using LiF TLD's. The technique can be used for the calibration of flat as well as curved surface applicators. Results for two flat and three concave applicators are presented. Our measurement of the surface dose rate for one of the flat applicators is compared with those obtained by four other institutions, each using different dosimetric devices

ACTH Regulation of Adrenal SR-B1

Directory of Open Access Journals (Sweden)

Wen-Jun eShen

2016-05-01

Full Text Available The adrenal gland is one of the prominent sites for steroid hormone synthesis. Lipoprotein-derived cholesterol esters delivered via scavenger receptor, class B type 1 (SR-B1 constitute the dominant source of cholesterol for steroidogenesis, particularly in rodents. ACTH stimulates steroidogenesis through downstream actions on multiple components involved in steroidogenesis. Both acute and chronic ACTH treatment can modulate SR-B1 function including its transcription, its post transcriptional stability, its phosphorylation and dimerization status, as well as its interaction with other protein partners; all of which result in changes in the ability of SR-B1 to mediate HDL-cholesterol ester uptake and the supply of cholesterol for conversion to steroids. Here we provide a review of the recent findings on the regulation of adrenal SR-B1 function by ACTH.

Rapid determination of {sup 90}Sr in urine samples using AnaLig Sr-01

Energy Technology Data Exchange (ETDEWEB)

Bilohuscin, J.; Dulanska, S.; Gardonova, V. [Univerzita Komenskeho, Prirodovedecka fakulta, Katedra jadrovej chemie, 84215 Bratislava (Slovakia)

2013-04-16

This work describes the use of IBC's AnaLig Sr-01 molecular recognition technology product to effectively and selectively pre-concentrate, separate and recover strontium from urine samples. This method uses two-stage columns separation consisting of two different commercial products Eichrom's Pre-filter Material and AnaLig Sr-01 column from IBC Advanced Technologies. This method does not involve co-precipitation of strontium as phosphates and oxalates from urine samples. The new rapid method separates strontium-90 with high chemical recovery (authors)

Development of an on-line flow injection Sr/matrix separation method for accurate, high-throughput determination of Sr isotope ratios by multiple collector-inductively coupled plasma-mass spectrometry.

Science.gov (United States)

Galler, Patrick; Limbeck, Andreas; Boulyga, Sergei F; Stingeder, Gerhard; Hirata, Takafumi; Prohaska, Thomas

2007-07-01

This work introduces a newly developed on-line flow injection (FI) Sr/Rb separation method as an alternative to the common, manual Sr/matrix batch separation procedure, since total analysis time is often limited by sample preparation despite the fast rate of data acquisition possible by inductively coupled plasma-mass spectrometers (ICPMS). Separation columns containing approximately 100 muL of Sr-specific resin were used for on-line FI Sr/matrix separation with subsequent determination of (87)Sr/(86)Sr isotope ratios by multiple collector ICPMS. The occurrence of memory effects exhibited by the Sr-specific resin, a major restriction to the repetitive use of this costly material, could successfully be overcome. The method was fully validated by means of certified reference materials. A set of two biological and six geological Sr- and Rb-bearing samples was successfully characterized for its (87)Sr/(86)Sr isotope ratios with precisions of 0.01-0.04% 2 RSD (n = 5-10). Based on our measurements we suggest (87)Sr/(86)Sr isotope ratios of 0.713 15 +/- 0.000 16 (2 SD) and 0.709 31 +/- 0.000 06 (2 SD) for the NIST SRM 1400 bone ash and the NIST SRM 1486 bone meal, respectively. Measured (87)Sr/(86)Sr isotope ratios for five basalt samples are in excellent agreement with published data with deviations from the published value ranging from 0 to 0.03%. A mica sample with a Rb/Sr ratio of approximately 1 was successfully characterized for its (87)Sr/(86)Sr isotope signature to be 0.718 24 +/- 0.000 29 (2 SD) by the proposed method. Synthetic samples with Rb/Sr ratios of up to 10/1 could successfully be measured without significant interferences on mass 87, which would otherwise bias the accuracy and uncertainty of the obtained data.

Effect of Flowing Water on Sr Sorption Changes of Hydrous Sodium Titanate

Directory of Open Access Journals (Sweden)

Youko Takahatake

2017-12-01

Full Text Available Radioactive contaminated water has been generated at the Fukushima Daiichi Nuclear Power station (F1NPS. Hydrous sodium titanate (SrTreat® is able to remove radioactive Strontium (Sr from this water. Knowing the amount of radioactive nuclides in the used as-received SrTreat® is important for effective disposal and deposition of the F1NPS waste. This study investigated changes in the ability of SrTreat® to sorb Sr, and to understand the causes of changes in the sorbing. An investigation of the Sr sorption ability of SrTreat® is important for calculating the initial radioactive inventory of used SrTreat®. This study carries out Sr sorption studies with acid-base titrations and X-ray photoelectron spectroscopy (XPS to characterize the properties. After exposure to simulated treated water for 99 h, the surface structure of the SrTreat® was changed, and the percentage of sorbed Sr and the buffer capacity for protons decreased. When the amount of radioactive nuclides contained in the used SrTreat® is calculated from the sorption data of the as-received SrTreat®, the radioactive Sr content will be overestimated with a concomitant increase in the deposition and disposal costs of the used SrTreat®.

Sr-containing hydroxyapatite: morphologies of HA crystals and bioactivity on osteoblast cells

Energy Technology Data Exchange (ETDEWEB)

Aina, Valentina [Department of Chemistry, Università degli Studi di Torino, Via P. Giuria 7, 10125 Torino (Italy); Centre of Excellence NIS (Nanostructured Interfaces and Surface) Università degli Studi di Torino (Italy); INSTM (Italian National Consortium for Materials Science and Technology), UdR Università di Torino (Italy); Bergandi, Loredana, E-mail: loredana.bergandi@unito.it [Department of Oncology, Università degli Studi di Torino, Via Santena 5/bis, 10126 Torino (Italy); Lusvardi, Gigliola; Malavasi, Gianluca [Department of Chemical and Geological Sciences, Università di Modena and Reggio Emilia, Via Campi 183, 41125 Modena (Italy); Imrie, Flora E.; Gibson, Iain R. [School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD (United Kingdom); Cerrato, Giuseppina [Department of Chemistry, Università degli Studi di Torino, Via P. Giuria 7, 10125 Torino (Italy); Centre of Excellence NIS (Nanostructured Interfaces and Surface) Università degli Studi di Torino (Italy); INSTM (Italian National Consortium for Materials Science and Technology), UdR Università di Torino (Italy); Ghigo, Dario [Department of Oncology, Università degli Studi di Torino, Via Santena 5/bis, 10126 Torino (Italy)

2013-04-01

A series of Sr-substituted hydroxyapatites (HA), of general formula Ca{sub (10−x)}Sr{sub x}(PO{sub 4}){sub 6}(OH){sub 2}, where x = 2 and 4, were synthesized by solid state methods and characterized extensively. The reactivity of these materials in cell culture medium was evaluated, and the behavior towards MG-63 osteoblast cells (in terms of cytotoxicity and proliferation assays) was studied. Future in vivo studies will give further insights into the behavior of the materials. A paper by Lagergren et al. (1975), concerning Sr-substituted HA prepared by a solid state method, reports that the presence of Sr in the apatite composition strongly influences the apatite diffraction patterns. Zeglinsky et al. (2012) investigated Sr-substituted HA by ab initio methods and Rietveld analyses and reported changes in the HA unit cell volume and shape due to the Sr addition. To further clarify the role played by the addition of Sr on the physico-chemical properties of these materials we prepared Sr-substituted HA compositions by a solid state method, using different reagents, thermal treatments and a multi-technique approach. Our results indicated that the introduction of Sr at the levels considered here does influence the structure of HA. There is also evidence of a decrease in the crystallinity degree of the materials upon Sr addition. The introduction of increasing amounts of Sr into the HA composition causes a decrease in the specific surface area and an enrichment of Sr-apatite phase at the surface of the samples. Bioactivity tests show that the presence of Sr causes changes in particle size and/or morphology during soaking in MEM solution; on the contrary the morphology of pure HA does not change after 14 days of reaction. The presence of Sr, as Sr-substituted HA and SrCl{sub 2,} in cultures of human MG-63 osteoblasts did not produce any cytotoxic effect. In fact, Sr-substituted HA increased the proliferation of osteoblast cells and enhanced cell differentiation: Sr in

Sr-containing hydroxyapatite: morphologies of HA crystals and bioactivity on osteoblast cells

International Nuclear Information System (INIS)

Aina, Valentina; Bergandi, Loredana; Lusvardi, Gigliola; Malavasi, Gianluca; Imrie, Flora E.; Gibson, Iain R.; Cerrato, Giuseppina; Ghigo, Dario

2013-01-01

A series of Sr-substituted hydroxyapatites (HA), of general formula Ca (10−x) Sr x (PO 4 ) 6 (OH) 2 , where x = 2 and 4, were synthesized by solid state methods and characterized extensively. The reactivity of these materials in cell culture medium was evaluated, and the behavior towards MG-63 osteoblast cells (in terms of cytotoxicity and proliferation assays) was studied. Future in vivo studies will give further insights into the behavior of the materials. A paper by Lagergren et al. (1975), concerning Sr-substituted HA prepared by a solid state method, reports that the presence of Sr in the apatite composition strongly influences the apatite diffraction patterns. Zeglinsky et al. (2012) investigated Sr-substituted HA by ab initio methods and Rietveld analyses and reported changes in the HA unit cell volume and shape due to the Sr addition. To further clarify the role played by the addition of Sr on the physico-chemical properties of these materials we prepared Sr-substituted HA compositions by a solid state method, using different reagents, thermal treatments and a multi-technique approach. Our results indicated that the introduction of Sr at the levels considered here does influence the structure of HA. There is also evidence of a decrease in the crystallinity degree of the materials upon Sr addition. The introduction of increasing amounts of Sr into the HA composition causes a decrease in the specific surface area and an enrichment of Sr-apatite phase at the surface of the samples. Bioactivity tests show that the presence of Sr causes changes in particle size and/or morphology during soaking in MEM solution; on the contrary the morphology of pure HA does not change after 14 days of reaction. The presence of Sr, as Sr-substituted HA and SrCl 2, in cultures of human MG-63 osteoblasts did not produce any cytotoxic effect. In fact, Sr-substituted HA increased the proliferation of osteoblast cells and enhanced cell differentiation: Sr in HA has a positive effect

Rapid Simultaneous Determination of 89Sr and 90Sr in Milk: A Procedure Using Cerenkov and Scintillation Counting

International Nuclear Information System (INIS)

2013-01-01

Since 2004, the IAEA programme related to the terrestrial environment has included activities aimed at developing and testing a set of procedures for the determination of radionuclides in environmental samples. Both 89Sr and 90Sr are fission products that can be, and have been, released to the environment during nuclear explosions and nuclear reactor accidents. Since strontium uptake from milk is an important pathway for incorporation of radioactive strontium into the human body, the rapid and accurate analysis of radioactive strontium isotopes in milk is of crucial importance in emergency situations in order to protect the public from radiation hazards. This report describes a new approach for the rapid determination of 89 Sr and 90Sr in milk using Cerenkov and scintillation counting methods that was tested and validated by the analysis of four spiked milk samples in terms of repeatability, reproducibility and trueness (relative bias) in accordance with ISO guidelines. The report also describes the calculation of the uncertainty budget. This research was proposed in 2007 at the Asia-Pacific regional meeting of the IAEA Analytical Laboratories for the Measurement of Environmental Radioactivity (ALMERA) network. Several ALMERA network laboratories participated in the validation procedure by performing reproducibility tests. The resulting recommended procedure is designed to be of general use to a wide range of laboratories, including those in the ALMERA network. It is expected that this rapid method for determining 89 Sr and 90 Sr in milk will be useful in emergency conditions and for routine environmental monitoring of elevated levels of radioactivity

Effect of SrO content on Zeolite Structure

Science.gov (United States)

Widiarti, N.; Sari, U. S.; Mahatmanti, F. W.; Harjito; Kurniawan, C.; Prasetyoko, D.; Suprapto

2018-04-01

The aims of current studies is to investigate the effect of strontium oxide content (SrO) on synthesized zeolite. Zeolite was synthesized from Tetraethyl orthosilicate (TEOS) as precursors of SiO2 and aluminum isopropoxide (AIP) precursors. The mixture was aged for 3 days and hydrothermally treated for 6 days. The SrO content was added by impregnation method. The products were then characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), and Surface Area Analyzer (SAA). The diffractogram confirmed the formation of Faujasite-like zeolite. However, after the addition of SrO, the crystallinity of zeolite was deformed. The diffractograms shows the amorphous phase of zeolite were decrease as the SrO content is increase. The structural changes was also observed from FTIR spectra which shows the shifting and peak formation. The surface area analysis showed that the increasing loading of SrO/Zeolites reduced the catalyst surface area.

Sr-90 determination in aqueous and soils samples

International Nuclear Information System (INIS)

Gonzalez Sintas, Maria F.; Cerchietti, Maria L.; Arguelles, Maria G.

2009-01-01

The main objective of this paper is to evaluate the method for Sr-90 determination in aqueous sample and soils. Area and Personal Dosimetry laboratory (DPA) determines the presence of Sr-90 by Liquid Scintillation (LSC) by applying method of the double window and corresponding adjustments. Calibration is performed by standard solutions of 90 Sr/ 90 Y, where spectral 90 Sr and 90 Y zones are optimized. The initial treatment of the liquid samples includes the concentration for evaporation, while the solid ones dissolve for microwave and acidic digestion. The separation of the analyte involves a selective chromatographic extraction. An average efficiency for 90 Sr of 77 ± 1 % was obtained; the factor a/b was 0,85 ± 0,01 and recovery of 82 ± 8 %. The resultant MAD was 0,10 Bq/L in aqueous samples and 0,10 Bq/g in solid samples. (author)

Anorthite glass: a potential host matrix for 90Sr pencil

International Nuclear Information System (INIS)

Sengupta, Pranesh; Dey, G.K.; Fanara, Sara; Chakraborty, Sumit; Mishra, R.K.; Kaushik, C.P.

2011-01-01

With rising global concerns over health hazards, environmental pollution and possible malicious applications of radioactive materials, there is an increasing consciousness among public and Governmental agencies for its better control, accounting and security. Investigations carried out by International Atomic Energy Agency and other monitoring bodies reveal that among various radioactive materials, the easily dispersible ones are high activity sealed sources (generally called radioactive pencils) used for various peaceful applications. Ideally, these sealed sources should be safely secured within specialized facilities, but in practice, it is not always done. Hence, there is a need to take an extra precautionary measure to ensure that the matrices currently used for hosting the radionuclides within sealed sources are durable enough under harsh service conditions and situations arising due to possible mishaps (accidents, misplaced, stolen etc). Among the variety of useful radionuclides, 90 Sr is one which is regularly used to (i) combat bone cancer, (ii) destroy unwanted tissue on the surface of eye/skin, (iii) light up/provide energy to remotely accessible areas etc. However, due to its (i) toxicity, (ii) mobility, (iii) easy incorporation within human body, (iv) considerable half-life (∼ 29 years), (v) emission of beta (β - ) particles along with high energy gamma ( γ)-rays, and (vi) retention of significant toxicity within sources even after service life, release of 90 Sr poses a serious threat to the biosphere. Hence, there is a need to ensure that existing 90 Sr host matrices are capable of withstanding all sorts of adversity that may arise during service and under storage/disposal

Resistance switching in epitaxial SrCoOx thin films

Science.gov (United States)

Tambunan, Octolia T.; Parwanta, Kadek J.; Acharya, Susant K.; Lee, Bo Wha; Jung, Chang Uk; Kim, Yeon Soo; Park, Bae Ho; Jeong, Huiseong; Park, Ji-Yong; Cho, Myung Rae; Park, Yun Daniel; Choi, Woo Seok; Kim, Dong-Wook; Jin, Hyunwoo; Lee, Suyoun; Song, Seul Ji; Kang, Sung-Jin; Kim, Miyoung; Hwang, Cheol Seong

2014-08-01

We observed bipolar switching behavior from an epitaxial strontium cobaltite film grown on a SrTiO3 (001) substrate. The crystal structure of strontium cobaltite has been known to undergo topotactic phase transformation between two distinct phases: insulating brownmillerite (SrCoO2.5) and conducting perovskite (SrCoO3-δ) depending on the oxygen content. The current-voltage characteristics of the strontium cobaltite film showed that it could have a reversible insulator-to-metal transition triggered by electrical bias voltage. We propose that the resistance switching in the SrCoOx thin film could be related to the topotactic phase transformation and the peculiar structure of SrCoO2.5.

Resistance switching in epitaxial SrCoOx thin films

International Nuclear Information System (INIS)

Tambunan, Octolia T.; Parwanta, Kadek J.; Acharya, Susant K.; Lee, Bo Wha; Jung, Chang Uk; Kim, Yeon Soo; Park, Bae Ho; Jeong, Huiseong; Park, Ji-Yong; Cho, Myung Rae; Park, Yun Daniel; Choi, Woo Seok; Kim, Dong-Wook; Jin, Hyunwoo; Lee, Suyoun; Song, Seul Ji; Kang, Sung-Jin; Kim, Miyoung; Hwang, Cheol Seong

2014-01-01

We observed bipolar switching behavior from an epitaxial strontium cobaltite film grown on a SrTiO 3 (001) substrate. The crystal structure of strontium cobaltite has been known to undergo topotactic phase transformation between two distinct phases: insulating brownmillerite (SrCoO 2.5 ) and conducting perovskite (SrCoO 3−δ ) depending on the oxygen content. The current–voltage characteristics of the strontium cobaltite film showed that it could have a reversible insulator-to-metal transition triggered by electrical bias voltage. We propose that the resistance switching in the SrCoO x thin film could be related to the topotactic phase transformation and the peculiar structure of SrCoO 2.5

Trace determination of 90Sr and 89Sr in environmental samples by collinear resonance ionization spectroscopy

International Nuclear Information System (INIS)

Lantzsch, J.; Bushaw, B. A.; Bystrow, V. A.; Herrmann, G.; Kluge, H.-J.; Niess, S.; Otten, E. W.; Passler, G.; Schwalbach, R.; Schwarz, M.; Stenner, J.; Trautmann, N.; Wendt, K.; Yushkevich, Y. V.; Zimmer, K.

1995-01-01

Collinear resonance ionization spectroscopy has been developed as a sensitive technique for fast trace detection of 90 Sr and 89 Sr in the environment. A detection limit for 90 Sr of 10 7 atoms in the presence of 10 17 atoms in the presence of 10 17 atoms of stable Strontium has been achieved, while the applicability of the method has been demonstrated on real world samples. After collection and chemical separation, strontium is surface ionized, accelerated to 33keV and mass separated. The ions are neutralized and the emerging fast atoms interact with an argon ion laser beam (γ=364 nm) in a quasi-collinear geometry. Optical excitation starts from the long-lived 5s4d 3 D2 state of strontium, which is populated in the charge exchange process, and the fast atoms are selectively excited into the high-lying 5s23f 3 F3 Rydberg state. The Rydberg-atoms are subsequently field-ionized and detected by a channeltron detector after energy selection. The described method was successfully used to determine the 90 Sr-content in air samples collected near Munich during the Chernobyl reactor accident in April 1986

Motivation and Pleasure Scale-Self-Report (MAP-SR): Validation of the German version of a self-report measure for screening negative symptoms in schizophrenia.

Science.gov (United States)

Engel, Maike; Lincoln, Tania Marie

2016-02-01

Validated self-report instruments could provide a time efficient screening method for negative symptoms in people with schizophrenia. The aim of this study was to examine the psychometric properties of a German version of the Motivation and Pleasure Scale-Self-Report (MAP-SR) which is based on the Clinical Assessment Interview for Negative Symptoms (CAINS). In- and outpatients (N=50) with schizophrenia or schizoaffective disorder were assessed with standardized interviews and questionnaires on negative and positive symptoms and general psychopathology in schizophrenia, depression, and global functioning. The German version of the MAP-SR showed high internal consistency. Convergent validity was supported by significant correlations between the MAP-SR with the experience sub-scale of the CAINS and the negative symptom sub-scale of the Positive and Negative Syndrome Scale. The MAP-SR also exhibited discriminant validity indicated by its non-significant correlations with positive symptoms and general psychopathology, which is in line with the findings for the original version of the MAP-SR. However, the MAP-SR correlated moderately with depression. The German MAP-SR appears to be a valid and suitable diagnostic tool for the identification of negative symptoms in schizophrenia. Copyright © 2015 Elsevier Inc. All rights reserved.

Radioresistance and immunization effectiveness under internal irradiation

International Nuclear Information System (INIS)

Kal'nitskij, S.A.

1978-01-01

The effect of preliminary immunization on the radioresistance of mice to internal irradiation from incorporated 137 Cs or 90 Sr was studied, and it was found that a preliminary single immunization with bacterial vaccines had a favorable effect on the outcome of radiation injury. The present results suggested that vaccination had a very pronounced radioprotective effect and so may be used as a means of biologic protection from internal irradiation

Unconventional superconductivity in Sr{sub 2}RuO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Liu, Ying [Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802 (United States); Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093 (China); Mao, Zhi-Qiang [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118 (United States)

2015-07-15

Highlights: • Constraints on and experimental support to unconventional superconductivity in Sr{sub 2}RuO{sub 4}. • Phase-sensitive determination of the pairing symmetry in Sr{sub 2}RuO{sub 4}. • Response of superconductivity to mechanical perturbations. • Superconductivity in non-bulk Sr{sub 2}RuO{sub 4}. • Unresolved issues and outlook in Sr{sub 2}RuO{sub 4} research. - Abstract: Sr{sub 2}RuO{sub 4}, featuring a layered perovskite crystalline and quasi-two-dimensional electronic structure, was first synthesized in 1959. Unconventional, p-wave pairing was predicted for Sr{sub 2}RuO{sub 4} by Rice and Sigrist and Baskaran shortly after superconductivity in this material was discovered in 1994. Experimental evidence for unconventional superconductivity in Sr{sub 2}RuO{sub 4} has been accumulating in the past two decades and reviewed previously. In this article, we will first discuss constraints on the pairing symmetry of superconductivity in Sr{sub 2}RuO{sub 4} and summarize experimental evidence supporting the unconventional pairing symmetry in this material. We will then present several aspects of the experimental determination of the unconventional superconductivity in Sr{sub 2}RuO{sub 4} in some detail. In particular, we will discuss the phase-sensitive measurements that have played an important role in the determination of the pairing symmetry in Sr{sub 2}RuO{sub 4}. The responses of superconductivity to the mechanical perturbations and their implications on the mechanism of superconductivity will be discussed. A brief survey of various non-bulk Sr{sub 2}RuO{sub 4} will also be included to illustrate the many unusual features resulted from the unconventional nature of superconductivity in this material system. Finally, we will discuss some outstanding unresolved issues on Sr{sub 2}RuO{sub 4} and provide an outlook of the future work on Sr{sub 2}RuO{sub 4}.

Topotactic phase transformation of the brownmillerite SrCoO2.5 to the perovskite SrCoO3- δ.

Science.gov (United States)

Jeen, H; Choi, W S; Freeland, J W; Ohta, H; Jung, C U; Lee, H N

2013-07-19

Pulsed laser epitaxy of brownmillerite SrCoO2.5 thin films and their phase transformation to the perovskite SrCoO3-δ are investigated. While the direct growth of the fully oxidized perovskite films is found to be an arduous task, filling some of oxygen vacancies into SrCoO2.5 by topotactic oxidation accompanies systematic evolution of electronic, magnetic, and thermoelectric properties, useful for many information and energy technologies. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Exogenous Sr2+ sedimentation on otolith of chum salmon embryos].

Science.gov (United States)

Wang, Chen; Liu, Wei; Zhan, Pei-rong; Wang, Ji-long; Li, Pei-lun

2015-10-01

To explore the exogenous Sr2+ sedimentation on otolith of chum salmon embryos, chum salmon embryos were exposed to culture water contained Sr2+ at Sr2+ concentration of 50, 100, 200 or 400 mg . L-1 for 48 h to imitate Sr2+ sedimentation. After a culturing period of 12 d and 100 d, the otoliths of the chum salmon were taken to detect exogenous Sr2+ sedimentation with electro-probe microanalyzer (EPMA). The results showed that obvious deep red strontium signatures were produced in the otolith of chum salmon at different concentrations of Sr2+. The mean and extreme values of peak strontium area were not stable for the same Sr2+ dose, but the lowest of all the peak values was 35.1 times as much as that of control. Overall, the strontium value increased with the increase of Sr2+concentration. The strontium peak had no signs of abating after a culture period of 100 d. The results also showed that strontium was gradually deposited in the otolith, and had obvious hysteresis to immersion. Strontium sedimentation could also return to a normal level after the peak. These characteristics accorded exactly with the requirement of discharge tag technology, which indicated that exogenous Sr2+ was suitable in the marking of salmon otolith.

Energy transfer in Pr3+ and Mn2+ co-doped SrB6O10 and SrB4O7

International Nuclear Information System (INIS)

Chen Yonghu; Yan Wuzhao; Shi Chaoshu

2007-01-01

The luminescent properties of Pr 3+ and Mn 2+ -doped SrB 6 O 10 and SrB 4 O 7 powder samples were investigated from the point of view of energy transfer between Pr 3+ and Mn 2+ . The emission from the 1 S 0 level of Pr 3+ was found in the SrB 6 O 10 :Pr 3+ sample as well as in the SrB 4 O 7 :Pr 3+ sample, indicating the 1 S 0 level is below the lowest 4f5d energy level in these hosts. The spectral overlaps between the emission spectra of Pr 3+ -doped samples and the excitation spectra of Mn 2+ -doped sample were found in both kinds of strontium borates. These spectral overlaps are in favor of the energy transfer from Pr 3+ to Mn 2+ . However, in the emission spectra of the SrB 6 O 10 :Pr 3+ , Mn 2+ , no indication of energy transfer was observed, though the emission spectra of SrB 4 O 7 :Pr 3+ , Mn 2+ did show evidence of energy transfer from Pr 3+ to Mn 2+ . The possible reasons were discussed

Rb-Sr isochrone dating of granitoids from Tribec Mts

International Nuclear Information System (INIS)

Bagdasaryan, G.P.; Gukasyan, R.Kh.; Cambel, B.; Broska, I.

1990-01-01

The results of Rb-Sr isochrone dating of granitoids from the Tribec-Zobor crystalline complex region are presented. Whole-rock Rb-Sr isochrone indicates an age of 352±5 m.y., the initial ratio being ( 87 Sr/ 86 Sr) 0 =0.70582±0.00008, which approaches the hitherto published initial ratios from the Tatric-Veporide part of the crystalline complex. This indicates a common source of granitoid rocks over the entire region studied. (author). 2 figs., 1 tab., 15 refs

Determination of Cs-137, Sr-89 and Sr-90 and gamma spectroscopy of water samples from the Danube River

International Nuclear Information System (INIS)

Tschurlovits, M.

1980-01-01

Radioactivity concentration of Cs-137, Sr-90, Sr-89, Co-60 and K-40 from the Danube water in the period of 1977-1979. A few systematic changes in the radioactivity concentrations were observed and presented. (author)

Blood-brain barrier in vitro models as tools in drug discovery: assessment of the transport ranking of antihistaminic drugs.

Science.gov (United States)

Neuhaus, W; Mandikova, J; Pawlowitsch, R; Linz, B; Bennani-Baiti, B; Lauer, R; Lachmann, B; Noe, C R

2012-05-01

In the course of our validation program testing blood-brain barrier (BBB) in vitro models for their usability as tools in drug discovery it was evaluated whether an established Transwell model based on porcine cell line PBMEC/C1-2 was able to differentiate between the transport properties of first and second generation antihistaminic drugs. First generation antihistamines can permeate the BBB and act in the central nervous system (CNS), whereas entry to the CNS of second generation antihistamines is restricted by efflux pumps such as P-glycoprotein (P-gP) located in brain endothelial cells. P-gP functionality of PBMEC/C1-2 cells grown on Transwell filter inserts was proven by transport studies with P-gP substrate rhodamine 123 and P-gP blocker verapamil. Subsequent drug transport studies with the first generation antihistamines promethazine, diphenhydramine and pheniramine and the second generation antihistamines astemizole, ceterizine, fexofenadine and loratadine were accomplished in single substance as well as in group studies. Results were normalised to diazepam, an internal standard for the transcellular transport route. Moreover, effects after addition of P-gP inhibitor verapamil were investigated. First generation antihistamine pheniramine permeated as fastest followed by diphenhydramine, diazepam, promethazine and second generation antihistaminic drugs ceterizine, fexofenadine, astemizole and loratadine reflecting the BBB in vivo permeability ranking well. Verapamil increased the transport rates of all second generation antihistamines, which suggested involvement of P-gP during their permeation across the BBB model. The ranking after addition of verapamil was significantly changed, only fexofenadine and ceterizine penetrated slower than internal standard diazepam in the presence of verapamil. In summary, permeability data showed that the BBB model based on porcine cell line PBMEC/C1-2 was able to reflect the BBB in vivo situation for the transport of

Method validation to measure Strontium-90 in urine sample for internal dosimetry assessment

International Nuclear Information System (INIS)

Bitar, A.; Maghrabi, M.; Alhamwi, A.

2010-12-01

Occupational individuals exposed at some scientific centers in Syrian Arab Republic to potentially significant intake by ingestion or inhalation during process of producing radiopharmaceutical compounds. The received radioactive intake differs in relation to the amount of radionuclides released during the preparation processes, to the work conditions and to the applying ways of the radiation protection procedures. TLD (Thermoluminescence Dosimeter) is usually used for external radiation monitoring for workers in radioisotope centers. During the external monitoring programme, it was noticed that some workers were exposed to high external dose resultant from radiation accident in their laboratory when preparing Y-90 from Sr-90. For internal dose assessment, chemical method to measure the amount of Sr-90 in urine samples was validated and explained in details in this study. Urine bioassays were carried out and the activities of 90 Sr were determined using liquid scintillation counter. Then, the validated method was used for internal occupational monitoring purposes through the design of internal monitoring programme. The programme was established for four workers who are dealing, twice per month, with an amount of about 20 mCi in each time. At the beginning, theoretical study was done to assess maximum risks for workers. Calculated internal doses showed that it is necessary to apply internal routine monitoring programme for those workers. (author)

Development of {sup 90}Sr-{sup 90}Y generators; Desenvolvimento de geradores de {sup 90}Sr-{sup 90}Y

Energy Technology Data Exchange (ETDEWEB)

Barrio, Graciela, E-mail: gracielabarrio@gmail.co [Pontificia Univ. Catolica de Sao Paulo (PUC-SP), SP (Brazil). Dept. de Fisica; Osso Junior, Joao Alberto, E-mail: jaossoj@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2007-07-01

Yttrium-90 is a radioisotope of great interest in the field of Nuclear Medicine. It is considered one of the most important and most used radionuclides for radioimmunotherapeutical applications, especially promising for the treatment of certain types of cancer. Another important application of {sup 90}Y is radio synovectomy. This radionuclide has a half-life of 64 hours, emits long range beta particles (maximum energy of 2.3 MeV) and decays, without intermediate nuclides, to a stable daughter. {sup 90}Y may be obtained carrier-free, generated by the decay of its parent {sup 90}Sr (half-life=28 years). {sup 90}Sr is a product from uranium fission, and due to its long half-life, can be indefinitely used, which is certainly advantageous. It is present in great amounts, and needs to be processed and purified in order to be used as raw material for the generators. Generators of {sup 90}Sr-{sup 90}Y may thus be used during various months, due to {sup 90}Sr long half-life. Several methods for the separation of {sup 90}Y from {sup 90}Sr by solvent extraction and ion exchange have been reported in literature. Thanks to its simplicity, ion exchange techniques have been more commonly used for this generator system. The main objective of this work was to develop a methodology for the preparation of {sup 90}Sr-{sup 90}Y generators, using cationic exchange resins. In such method, {sup 90}Sr is strongly adsorbed in the resin and {sup 90}Y is eluted by a 0.003 M EDTA solution. According to the quality control carried out, results showed that elution yields are greater than 65%, thus confirming the efficiency of the separation method used.

Adsorption of UO22+ in surfaces of SrTiO3

International Nuclear Information System (INIS)

Ortiz O, H.B.; Ordonez R, E.; Fernandez V, S.M.

2005-01-01

The internationally accepted solution in the administration of the high level radioactive residuals is the multi barrier deep geologic storage which should guarantee that do not exist flights neither transfer of residuals to the atmosphere in time periods of at least 10,000 years. In this confinement type exists the interest to study materials that can be used as engineering barriers as well as the diverse interaction phenomena between these and the radionuclides. In this work it is presented the physicochemical characterization and evaluation of the surface properties and of adsorption of U(VI) in form of UO 2 (NO 3 ) 2 on the SrTiO 3 like possible candidate for contention barrier in the deep geologic confinement. The made studies showed that the SrTiO 3 is stable to temperatures between 0 and 800 C. At the same time it could settle down that the maximum sorption percentages are reached to near pH to the isoelectric point, where chemical species prevail in solution of the type UO 2 (X) - . (Author)

Nature and Significance of the High-Sr Aleutian Lavas

Science.gov (United States)

Yogodzinski, G. M.; Arndt, S.; Turka, J. R.; Kelemen, P. B.; Vervoort, J. D.; Portnyagin, M.; Hoernle, K.

2011-12-01

Results of the Western Aleutian Volcano Expedition and German-Russian KALMAR cruises include the discovery of seafloor volcanism at the Ingenstrem Depression and at unnamed seamounts 300 km west of Buldir, the westernmost emergent volcano in the Aleutian arc. These discoveries indicate that the surface expression of active Aleutian volcanism goes below sea level just west of Buldir, but is otherwise continuous along the full length of the arc. Many lavas dredged from western Aleutian seamounts are basalts, geochemically similar to basalts from elsewhere in Aleutians and other arcs (La/Yb 4-8, Sr/Y700 ppm Sr), which are mostly plagioclase-hornblende andesites and dacites with low Y and middle-heavy rare-earth elements, fractionated trace element patterns (Sr/Y=50-200, La/Yb=9-25) and MORB-like isotopes (87Sr/86Sr 0.65) with 1250-1700 ppm Sr, 4-7 ppm Y, low abundances of all rare-earth elements (LaMexico. [1] Zimmer et al., 2010, J. Petrology, v. 51, p. 2411

Analysis of uncertainties and detection limits for the double measurement method of {sup 90}Sr and {sup 89}Sr

Energy Technology Data Exchange (ETDEWEB)

Herranz, M., E-mail: m.herranz@ehu.es [Department of Nuclear Engineering and Fluid Mechanics, University of the Basque Country (UPV/EHU), Alameda de Urquijo s/n 48013 Bilbao (Spain); Idoeta, R.; Legarda, F. [Department of Nuclear Engineering and Fluid Mechanics, University of the Basque Country (UPV/EHU), Alameda de Urquijo s/n 48013 Bilbao (Spain)

2011-08-15

The determination process of the {sup 90}Sr and {sup 89}Sr contents in a sample, although it involves their radiochemical isolation, results always in a complex measurement process due to the interferences among their respective beta emissions and also among those of the daughter of {sup 90}Sr, {sup 90}Y, a beta emitter as well. In this paper, the process consisting in a double measurement method after the Sr radiochemical isolation is analyzed, developing the formulae to obtain activity concentrations, uncertainties and detection limits. A study of the trend of uncertainties and detection limits as function of the time in which the first measurement since the isolation is done, the delay between the two measurements and the activity concentration of each strontium isotope in the sample is carried out as well. Results show that with a very precise determination of the times involved in the whole process (isolation, measurement and duration of measurements) this method permits a reliable assessment of both strontium radioisotopes. The quicker the first measurement since the isolation is done and the longer the delay between measurements is chosen, the lower are the detection limits and the uncertainties of the activities obtained. - Highlights: > The double measurement method for {sup 90}Sr and {sup 89}Sr determination is analysed. > Uncertainties and detection limits are determined and their dependences studied. > Proposals for the optimization of the method are given.

Physiological studies in heterozygous calcium sensing receptor (CaSR gene-ablated mice confirm that the CaSR regulates calcitonin release in vivo

Directory of Open Access Journals (Sweden)

Kovacs Christopher S

2004-04-01

Full Text Available Abstract Background The calcium sensing receptor (CaSR regulates serum calcium by suppressing secretion of parathyroid hormone; it also regulates renal tubular calcium excretion. Inactivating mutations of CaSR raise serum calcium and reduce urine calcium excretion. Thyroid C-cells (which make calcitonin express CaSR and may, therefore, be regulated by it. Since calcium stimulates release of calcitonin, the higher blood calcium caused by inactivation of CaSR should increase serum calcitonin, unless CaSR mutations alter the responsiveness of calcitonin to calcium. To demonstrate regulatory effects of CaSR on calcitonin release, we studied calcitonin responsiveness to calcium in normal and CaSR heterozygous-ablated (Casr+/- mice. Casr+/- mice have hypercalcemia and hypocalciuria, and live normal life spans. Each mouse received either 500 μl of normal saline or one of two doses of elemental calcium (500 μmol/kg or 5 mmol/kg by intraperitoneal injection. Ionized calcium was measured at baseline and 10 minutes, and serum calcitonin was measured on the 10 minute sample. Results At baseline, Casr+/- mice had a higher blood calcium, and in response to the two doses of elemental calcium, had greater increments and peak levels of ionized calcium than their wild type littermates. Despite significantly higher ionized calcium levels, the calcitonin levels of Casr+/- mice were consistently lower than wild type at any ionized calcium level, indicating that the dose-response curve of calcitonin to increases in ionized calcium had been significantly blunted or shifted to the right in Casr+/- mice. Conclusions These results confirm that the CaSR is a physiological regulator of calcitonin; therefore, in response to increases in ionized calcium, the CaSR inhibits parathyroid hormone secretion and stimulates calcitonin secretion.

Photoluminescence in Pb{sup 2+} activated SrB{sub 4}O{sub 7} and SrB{sub 2}O{sub 4} phosphors

Energy Technology Data Exchange (ETDEWEB)

Gawande, A.B., E-mail: gawandeab@gmail.com [Department of Physics, SGB Amravati University, Amravati-444602, Maharashtra (India); Ingle, J.T. [J. D. Institute of Engineering and Technology, Yavatmal, Maharashtra (India); Sonekar, R.P., E-mail: sonekar_rp@yahoo.com [Department of Physics, G.S. College, Khamgaon District, Buldhana, Maharashtra (India); Omanwar, S.K. [Department of Physics, SGB Amravati University, Amravati-444602, Maharashtra (India)

2014-05-01

The powder samples of SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} were prepared by solution combustion synthesis method. The synthesis is based on the exothermic reaction between the fuel (Urea) and Oxidizer (Ammonium nitrate). The synthesized materials were characterized using TG–DTA, powder XRD, SEM and the photoluminescence properties were studied using a Hitachi F-7000 spectrophotometer at room temperature. Both the samples SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} show broad emission of Pb{sup 2+} respectively at 307 nm and 360 nm (corresponds to {sup 3}P{sub 1} to {sup 1}S{sub 0} transition). The optimum concentrations of Pb{sup 2+} in both the phosphors SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} were found to be 3 mol% (relative to Sr) and for this concentration the critical transfer distance R{sub 0} were calculated to be 10.21 Å and 12.22 Å respectively. The Stokes shifts were calculated to be respectively 4464 cm{sup −1} and 8454 cm{sup −1}. The emission bands of both the phosphors are in the UV region and the phosphors can be potential candidates for application in UV lamps. - Highlights: • SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} have been synthesized by Novel solution combustion synthesis technique. • The synthesized materials were characterized using TG–DTA, powder XRD and SEM. • Photoluminescence spectra of synthesized materials showed the characteristic transition in Pb{sup 2+}. • Stokes shift, optimum concentration and critical transfer distance R{sub 0} were determined.

The combined use of 87Sr/86Sr and carbon and water isotopes to study the hydrochemical interaction between groundwater and lakewater in mantled karst

Science.gov (United States)

Katz, Brian G.; Bullen, Thomas D.

1996-12-01

The hydrochemical interaction between groundwater and lakewater influences the composition of water that percolates downward from the surficial aquifer system through the underlying intermediate confining unit and recharges the Upper Floridan aquifer along highlands in Florida. The 87Sr/86Sr ratio along with the stable isotopes, D, 18O, and 13C were used as tracers to study the interaction between groundwater, lakewater, and aquifer minerals near Lake Barco, a seepage lake in the mantled karst terrane of northern Florida. Upgradient from the lake, the 87Sr/86Sr ratio of groundwater decreases with depth (mean values of 0.71004, 0.70890, and 0.70852 for water from the surficial aquifer system, intermediate confining unit, and Upper Floridan aquifer, respectively), resulting from the interaction of dilute oxygenated recharge water with aquifer minerals that are less radiogenic with depth. The concentrations of Sr2+ generally increase with depth, and higher concentrations of Sr2+ in water from the Upper Floridan aquifer (20-35 μg/L), relative to water from the surficial aquifer system and the intermediate confining unit, result from the dissolution of Sr-bearing calcite and dolomite in the Eocene limestone. Dissolution of calcite [δ13C= -1.6permil(‰)] is also indicated by an enriched δ13CDIC(-8.8 to -11.4 ‰) in water from the Upper Floridan aquifer, relative to the overlying hydrogeologic units (δ13CDICaquifer material become less radiogenic and the Sr2+ concentrations generally increase with depth. However, Sr2+ concentrations are substantially less than in upgradient groundwaters at similar depths. The lower Sr2+ concentrations result from the influence of anoxic lakewater leakage on the mobility of Sr2+ from clays. Based on results from mass-balance modeling, it is probable that cation exchange plays the dominant role in controlling the 87Sr/86Sr ratio of groundwater, both upgradient and downgradient from Lake Barco. Even though groundwater from the three

International Expert Review of SRCan: Site Investigation Aspects. External review contribution in support of SKI's and SSI's review of SR-Can. INSITE/OVERSITE

International Nuclear Information System (INIS)

2008-03-01

As a first evaluation of long-term safety for KBS-3 repositories at Forsmark and Laxemar, the SIG (Site Investigation Group) found SR-Can to be a well-produced and generally well-argued safety assessment. Overall, SKB is to be complimented on this project. Members of of the two groups INSITE and OVERSITE within the SIG had somewhat differing views on how well SKB had made use of the site data available at the end of the SDM 1.2 stage of investigations. This difference is less to do with the extent of site characterisation than of its use and application, reflecting the different levels of maturity of SKB's geosphere and biosphere assessment programmes. The more recent and current work on the sites means that our concerns expressed in this review should, to a large extent, be addressable in or prior to SR-Site, provided SKB is so minded. However, we acknowledge that some of the issues we raise will not be fully resolved until underground rock characterisation from excavations or longer records of surface conditions are available. There are also some key aspects of SKB's methodology still under development that would benefit from review prior to their use in SR-Site. More space in the currently pressing schedule would allow for this review and a consequent increase in confidence. In any case, the authorities should be aware that SKB may face residual programmatic risks, associated principally with the underground design and layout (and their knockon effects into performance), even after SR-Site. An early understanding of some of these relationships would be helped by a plan (at least on an outline level) of the underground characterisation programme. We also note that many engineering matters are still to be confronted, not least the EBS design and its implementation, along with the treatment of high stresses, if Forsmark is selected. However, our views on the nature of the SR-Can analysis and the way in which site data have been utilised in it (our principal remit

Some analytical aspects about determination of Sr89 and Sr90 in environmental samples

International Nuclear Information System (INIS)

Gasco, C.; Alvarez Garcia, A.

1988-01-01

Some problems about determination of Sr 89 and Sr 90 in environmental samples have been studied. The main difficulties are due to the wide range in the concentration of their components and the contents of chemical and radiochemical interferent elements. The behaviour of strontium on ion exchange resin has been described by some experiments in various media: aqueous media, calcium concentration and matrix variable. The differences of alkaline-earth nitrate and carbonate solubilities have been analyzed in nitric acid. The chemical recovery in environmental samples has been determined. (Author)

Spark plasma sintering of bulk SrAl2O4-Sr3Al2O6 eutectic glass with wide-band optical window

Science.gov (United States)

Liu, Jiaxi; Lu, Nan; He, Gang; Li, Xiaoyu; Li, Jianqiang; Li, Jiangtao

2018-06-01

SrAl2O4-Sr3Al2O6 eutectic glass was prepared by using an aerodynamic levitator equipped with a CO2 laser device. A bulk transparent amorphous sample was obtained by the spark plasma sintering (SPS) of the prepared eutectic glass. XRD, a UV–vis-NIR spectrophotometer and FT-IR were employed to characterize the phase evolution and optical properties. The results show that the bulk SrAl2O4-Sr3Al2O6 samples fabricated by the containerless process and SPS between 852 °C–857 °C were fully amorphous. The amorphous sample has a wide transparent window between 270 nm and 6.2 μm. The average refractive index in the visible light region is 1.680 and the Abbe number is 27.4. The prepared bulk SrAl2O4-Sr3Al2O6 eutectic glass with the wide-band optical window may be a promising candidate for optical applications.

High-pressure modifications of CaZn2, SrZn2, SrAl2, and BaAl2: Implications for Laves phase structural trends

International Nuclear Information System (INIS)

Kal, Subhadeep; Stoyanov, Emil; Belieres, Jean-Philippe; Groy, Thomas L.; Norrestam, Rolf; Haeussermann, Ulrich

2008-01-01

High-pressure forms of intermetallic compounds with the composition CaZn 2 , SrZn 2 , SrAl 2 , and BaAl 2 were synthesized from CeCu 2 -type precursors (CaZn 2 , SrZn 2 , SrAl 2 ) and Ba 21 Al 40 by multi-anvil techniques and investigated by X-ray powder diffraction (SrAl 2 and BaAl 2 ), X-ray single-crystal diffraction (CaZn 2 ), and electron microscopy (SrZn 2 ). Their structures correspond to that of Laves phases. Whereas the dialuminides crystallize in the cubic MgCu 2 (C15) structure, the dizincides adopt the hexagonal MgZn 2 (C14) structure. This trend is in agreement with the structural relationship displayed by sp bonded Laves phase systems at ambient conditions. - Graphical abstract: CeCu 2 -type polar intermetallics can be transformed to Laves phases upon simultaneous application of pressure and temperature. The observed structures are controlled by the valence electron concentration

Experimental investigation and thermodynamic calculation of the Mg-Sr-Zr system

International Nuclear Information System (INIS)

Zhou, Hua; Chen, Chong; Du, Yong; Central South Univ., Hunan; Gong, Haoran

2016-01-01

Both experimental investigation and thermodynamic calculation were performed for the Mg-Sr-Zr system. Four decisive alloys were firstly selected and prepared using a powder metallurgy method to measure the isothermal section at 400 C via a combination of X-ray diffraction and electron probe microanalysis. No ternary compound has been observed for this ternary system. Four three-phase regions, (Mg) + (αZr) + Mg 17 Sr 2 , Mg 17 Sr 2 + (αZr) + Mg 38 Sr 9 , Mg 38 Sr 9 + (αZr) + Mg 23 Sr 6 , and Mg 23 Sr 6 + (αZr) + Mg 2 Sr, have been identified at 400 C. No appreciable ternary solubility has been detected in the binary Mg-Sr compounds. Phase transition temperatures of the Mg-Sr-Zr alloys were measured by means of differential scanning calorimetry. The thermodynamic calculations match well with the experimental data in the present work, indicating that no ternary thermodynamic parameters are needed for the thermodynamic description of this ternary system. In order to verify the reliability of the current thermodynamic calculations of the Mg-Sr-Zr system, eight as-cast alloys in the Mg-rich corner were also prepared. The calculated liquidus projection is consistent with the observed primary phase regions. The present thermodynamic calculations are reliable and can be used in the development of Mg alloys.

Strontium adsorption and penetration in kaolinite at low Sr

NARCIS (Netherlands)

Ning, Zigong; Ishiguro, Munehide; Koopal, Luuk K.; Sato, Tsutomu; Kashiwagi, Junichi

2017-01-01

Behavior of radioactive strontium (Sr2+) in contaminated soils is an important issue in relation to nuclear power plant accidents. The Sr2+ adsorption on kaolinite and its migration in a kaolinite soil were investigated because toxic effects of radioactive Sr2+ have been found to be very severe for

87Sr/86Sr in gypsic soils of hyperarid settings as an altitude proxy: results for northern Chile (19-22°S) and paleoaltimetry applications

Science.gov (United States)

Cosentino, N. J.; Jordan, T. E.; Derry, L. A.

2012-12-01

Quantification of uplift of a continental surface relative to sea level is still challenging. We have developed a new altimeter based on the 87Sr/86Sr ratio of modern accumulations of salts (incipient soils) in hyperarid settings like those present in northern Chile's Atacama Desert, which lies in the forearc of the Nazca-South America plate system. The proposed altimeter is based on the first order topographic control on the extent of coastal fog. Advective events bring offshore-generated stratocumulus clouds to the continent, generating fog between 400 and 1100 m.a.s.l.. In the hyperarid desert, thin layers of calcium sulfate, among other salts, accumulate on the surface. The main sources of the calcium sulfates are i) Pacific-sourced fog that transports aerosols and dissolved salts inland, which are precipitated upon evaporation, ii) wind that transports salts derived from the weathering of Andean magmatic arc rocks, which may be recycled through salars, and to a lesser extent, iii) salts derived from volcanic emissions. While the latter two have an average 87Sr/86Sr isotopic ratio of 0.70749, the fog source has a value corresponding to seawater (0.70917). Due to the high atomic weight of Sr and to the low relative mass difference of isotopes 87Sr and 86Sr, environmental isotopic fractionation is minimal. This makes 87Sr/86Sr an excellent proxy for the primary source of the calcium sulfates and the calcium sulfates' Sr. Samples from four E-W transects of the forearc between 19.75° to 23.75° S demonstrate variations in 87Sr/86Sr for altitudes between 200 and 2700 m.a.s.l.. There is a correlation between the modern salts' 87Sr/86Sr and its altitude of formation for altitudes between ~400 and ~800 m.a.s.l., above which the 87Sr/86Sr falls abruptly until reaching values similar to or lower than the Andean average. The fact that this correlation is observed for the whole dataset (including all four transects) suggests that the relationship is regional rather than

RADIOISOTOPE INVENTORY FOR TSPA-SR

International Nuclear Information System (INIS)

Leigh, C.; Rechard, R.

2001-01-01

The total system performance assessment for site recommendation (TSPA-SR), on Yucca Mountain, as a site (if suitable) for disposal of radioactive waste, consists of several models. The Waste Form Degradation Model (i.e, source term) of the TSPA-SR, in turn, consists of several components. The Inventory Component, discussed here, defines the inventory of 26 radioisotopes for three representative waste categories: (1) commercial spent nuclear fuel (CSNF), (2) US Department of Energy (DOE) spent nuclear fuel (DSNF), and (3) high-level waste (HLW). These three categories are contained and disposed of in two types of waste packages (WPs)--CSNF WPs and co-disposal WPs, with the latter containing both DSNF and HLW. Three topics are summarized in this paper: first, the transport of radioisotopes evaluated in the past; second, the development of the inventory for the two WP types; and third, the selection of the most important radioisotopes to track in TSPA-SR

The spatial variation of initial 87Sr/86Sr ratios in the Toki granite, Central Japan. Implications for the intrusion and cooling processes of a granitic pluton

International Nuclear Information System (INIS)

Yuguchi, Takashi; Tsuruta, Tadahiko; Hama, Katsuhiro; Nishiyama, Tadao

2013-01-01

The spatial variation in initial 87 Sr/ 86 Sr ratios (SrI) in the Toki granite, Central Japan, shows heterogeneity ranging from 0.708942 to 0.710069, which provides information on the intrusion and cooling processes of plutons. The Toki granite has three mineralogy-based rock facies: muscovite-biotite granite (MBG), hornblende-biotite granite (HBG) and biotite granite (BG). Large SrI values were found to be distributed at the western margin (west MBG) and the lithologically central region (central BG), while small SrI values were found at the northeast margin (northeast MBG). Regions with high and low Sr concentrations were also found in the Toki granite. In the Sr-rich samples, SrI (0.708942-0.709789) increases with 100/Sr (0.7-1.5). This geochemical trend extends towards the country sedimentary rocks of the Mino Terrane, which can be interpreted to result from assimilation and fractional crystallization (AFC) between the original granitic magma and the Mino sedimentary rocks. The SrI values in the Sr-rich regions show a correlation with the Alumina Saturation Index (ASI). In particular, the west MBG, with large SrI values, is classified as a peraluminous granitoid with large ASI, suggesting that the western margin of the pluton was strongly affected by assimilation during the intrusion process. The Sr-poor samples are present both in the central BG, with large SrI values, and in the northeast MBG, with small SrI values. The Sr-poor samples have small ASI and large differentiation indices, indicating that the central BG and the northeast MBG were generated either by different AFC process with different amounts of contaminants or by the intrusion and fractionation of different source magma with different SrI values. Overall, the geochemical spatial variations found in the Toki granite can be explained by various degrees of assimilation and fractional crystallization in the magma chamber and/or multi-stage intrusions with different degrees of crystallization of

Geochemical tracing of As pollution in the Orbiel Valley (southern France): 87Sr/86Sr as a tracer of the anthropogenic arsenic in surface and groundwater.

Science.gov (United States)

Khaska, Mahmoud; Le Gal La Salle, Corinnne; Lancelot, Joël; Verdoux, Patrick; Boutin, René

2014-05-01

The environmental impacts of arsenic mining activities and their effects on ecosystem and human health are observed in many stream waters and groundwater. The aim of this study is to identify the origin of As content in a mining environment using Sr isotopes. At the Salsigne gold mine, before the closure in 2004, high arsenic content has been observed in surface water and groundwater in the Orbiel valley. At the site, immobilization of As, in As rich leachate, is carried out by adding CaO. High contrast in 87Sr/86Sr between Arsenic rich minerals associated with Variscan metamorphic rocks (0.714888-0.718835), together with rich As waste water (0.713463-715477), and the CaO (0.707593) allows as to trace the origin of anthropogenic As. In 2012, Orbiel stream waters were sampled monthly upstream and downstream from the ancient ore processing site and once after an important rainy event (117mm). The upstream valley samples showed low and relatively constant As content with natural regional background of 3.6 and 5.6 μg/L. The rainy event induced only a slight increase in the As content up to 6.3 μg/L. High 87Sr/86Sr ratios suggested an influence of radiogenic Sr issued from the Variscan metamorphic basement. Downstream from the area, the As content was at least10 time as high. In the wet season, stream water As content clearly increased to 13.9-24 μg/L, reaching 120.5 μg/L during the rainy event. Associated 87Sr/86Sr ratio showed to be less radiogenic (0.712276-0.714002). The anti correlation observed between As and 87Sr/86Sr suggest that As issued from a natural origin is characterised by a high 87Sr/86Sr compared to As derived from the CaO treatement used on site and characterized by a low 87Sr/86Sr ratio. During the dry season, increase in As content was observed reaching 110 μg/L. These highlights the contribution of alluvial groundwater to base flow, probably associated with As reach leachate from the site. Contribution from the alluvial aquifer is confirmed by

Observation of Isotope Ratios (δ2H, δ18O, 87Sr/86Sr) of Tap Water in Urban Environments

Science.gov (United States)

Mancuso, C. J.; Tipple, B. J.; Ehleringer, J. R.

2014-12-01

Urban environments are centers for rapidly growing populations. In order to meet the culinary water needs of these areas, municipal water departments use water from multiple locations and/or sources, often piped differentially to different locations within a municipality. This practice creates isotopically distinct locations within an urban area and therefore provides insight to urban water management practices. In our study we selected urban locations in the Salt Lake Valley, UT (SLV) and San Francisco Bay Area, CA (SFB) where we hypothesized geographically distinct water isotopic ratio differences existed. Within the SLV, municipal waters come from the same mountainous region, but are derived from different geologically distinct watersheds. In contrast, SFB waters are derived from regionally distinct water sources. We hypothesized that the isotope ratios of tap waters would differ based upon known municipal sources. To test this, tap water samples were collected throughout the urban regions in SLV and SFB and analyzed for δ2H, δ18O and 87Sr/86Sr isotope ratios. Seasonal collections were also made to assess if isotope ratios differed throughout the year. Within SLV and SFB, different regions were characterized by distinct paired δ18O and 87Sr/86Sr values. These different realms also agreed with known differences in municipal water supplies within the general geographic region. Waters from different cities within Marin County showed isotopic differences, consistent with water derived from different local reservoirs. Seasonal variation was observed in paired δ18O and 87Sr/86Sr values of tap water for some locations within SLV and SFB, indicating management decisions to shift from one water source to another depending on demand and available resources. Our study revealed that the δ18O and 87Sr/86Sr values of tap waters in an urban region can exhibit significant differences despite close spatial proximity if districts differ in their use of local versus

Report on nuclear energy in SR Slovenia

International Nuclear Information System (INIS)

1987-01-01

Currently Yugoslavia has one 632 MWe nuclear power plant (NPP) of PWR design, located at Krsko in the Socialist Republic (SR) of Slovenia. Krsko NPP, which is a two-loop plant, started power operation in 1981. In general, reactor safety activities in the SR of Slovenia are mostly related to upgrading the safety of our Krsko NPP and to developing capabilities for use in future units. This report presents the nuclear safety related legislation and organization of the corresponding regulatory body, and the activities related to nuclear safety of the participating organizations in the SR of Slovenia in 1987.

Transesterification of soybean oil catalyzed by Sr-doped cinder

International Nuclear Information System (INIS)

Nasreen, Sadia; Liu, Hui; Khan, Romana; Zhu, Xiao-chan; Skala, Dejan

2015-01-01

Highlights: • Sr-doped cinder catalyst was prepared and used for biodiesel synthesis. • A 99% of triglycerides conversion was achieved under optimal reaction conditions. • SrAl 2 Si 2 O 8 and Sr 5 Al 8 O 1 are determined as dominant compounds which are responsible for high catalytic activity. • Catalyst exhibits high activity and can be easily recovered and regenerated. • The Sr-doped cinder catalyst is used in 14 repeated runs. - Abstract: The Strontium doped cinder was prepared using the wet impregnation method and analyzed as catalyst for biodiesel synthesis. Different procedure for cinder impregnation were investigated (temperature and duration of catalyst calcinations, the concentration of SrCl 2 solution) and optimal condition was established: impregnation 20 g of cinder 2–5 mm particles with 0.2 M SrCl 2 solution followed by calcinations at 1000 °C for 4 h. The Sr-cinder activity was tested at 90–200 °C using 1–5% mass of catalyst with different molar ratio of methanol to soybean oil (from 9 to 36). The maximum triglycerides (TG) conversion of 99.0% with the Fatty Acid Methyl Esters (FAME) yield of 97.1% was obtained by using 4% catalyst at 180 °C, for 1 h, and methanol/oil molar ratio 24:1. Influence of free fatty acid (FFA) and water in soybean oil on catalyst activity was analyzed, too. The catalyst could be used for 14 times with TG conversion and FAME yield above 90% and 80% respectively. The Sr-doped cinder catalysts before and after transesterification were characterized using BET surface area, basic strength, X-ray diffraction (XRD), scanning electron microscopy (SEM) and ICP-AAS. Results showed that the formation of SrAl 2 Si 2 O 8 and Sr 5 Al 8 O 17 complexes should be the main reason for the catalytic activity of prepared catalyst. Slow decrease of catalyst activity during its repeated use is result of Sr–Al-glycerolate formation in reaction between Sr–Al complexes and glycerol

Screening for major and minor depression in a multiethnic sample of Asian primary care patients: a comparison of the nine-item Patient Health Questionnaire (PHQ-9) and the 16-item Quick Inventory of Depressive Symptomatology - Self-Report (QIDS-SR16 ).

Science.gov (United States)

Sung, Sharon Cohan; Low, Charity Cheng Hong; Fung, Daniel Shuen Sheng; Chan, Yiong Huak

2013-12-01

Depression is common, disabling, and the single most important factor leading to suicide, yet it is underdiagnosed in busy primary care settings. A key challenge facing primary care clinicians in Asia is the selection of instruments to facilitate depression screening. Although the nine-item Patient Health Questionnaire (PHQ-9) and 16-item Quick Inventory of Depressive Symptomatology - Self-Report (QIDS-SR16 ) are used internationally, they have not been directly compared or widely validated in Asian primary care populations. This study aimed to validate the PHQ-9 and QIDS-SR16 against a structured interview diagnosis of Diagnostic and Statistical Manual, 4th Edition, depression based on the Mini-International Neuropsychiatric Interview in a multiethnic Asian sample. From April through August 2011, we enrolled 400 English-speaking Singaporean primary care patients. Participants completed a demographic data form, the PHQ-9, and the QIDS-SR16 . They were assessed independently for major and minor depression using the Mini-International Neuropsychiatric Interview. Sensitivity and specificity for diagnosing major depression were 91.7% and 72.2%, respectively, for the PHQ-9 (optimal cutoff score of 6), and 83.3% and 84.7%, respectively, for the QIDS-SR16 (optimal cutoff score of 9). The QIDS-SR16 also detected minor depression at an optimal cutoff score of 7, with a sensitivity of 94.4% and specificity of 77.9%. The PHQ-9 and QIDS-SR16 showed good internal consistency (Cronbach's α: 0.87 and 0.79, respectively) and good convergent validity (correlation coefficient: r = 0.73, P depressive disorders was 9%. The PHQ-9 and QIDS-SR16 appear to be valid and reliable for depression screening in Asian primary care settings. Copyright © 2013 Wiley Publishing Asia Pty Ltd.

Depth dose distribution in the water for clinical applicators of 90Sr + 90Y, with a extrapolation mini chamber

International Nuclear Information System (INIS)

Antonio, Patricia de Lara; Caldas, Linda V.E.; Oliveira, Mercia L.

2009-01-01

This work determines the depth dose in the water for clinical applicators of 90 Sr + 90 Y, using a extrapolation mini chamber developed at the IPEN, Sao Paulo, Brazil, and different thickness acrylic plates. The obtained results were compared with the international recommendations and were considered satisfactory

Study on sorption capacity and characterization of Sr2+ on synthetic zeolite

International Nuclear Information System (INIS)

Wang Jinming; Yi Facheng

2010-01-01

Sr 2+ adsorption capacity of synthetic zeolite(ZF) are studied with the intermittence method, and ZF adsorbed the Sr 2+ is characterized and analyzed by XRD, as a reference for the evaluation of the disposal effectiveness of low and medium radwastes. The results show that Sr 2+ adsorption capacity of ZF is good, and the equilibrium time for ZF to adsorb Sr 2+ is in range of 5-14 days. Sr 2+ concentration has the greatest effect on ZF adsorption capacity,and the medium,temperature and pH value of the solution also have effect on ZF adsorption capacity. With the augment of Sr 2+ concentration,the Sr 2+ equilibrium adsorption quantity of ZF increases,but the equilibrium adsorption rate and equilibrium adsorption ratio decreases. Sr 2+ adsorption capacity of ZF improves with the augment of pH value. Sr 2+ adsorption capacity of ZF is complicate and varies with the different ion, concentration and other components in the medium solution. Sr 2+ adsorption capacity of ZF increases with the augment of temperature. As a whole, when Sr 2+ concentration in the solution is 0.005mol/L, the pH value of the solution, and the temperature of medium and solution have less effect on the Sr 2+ adsorption capacity of ZF, and the unit cell parameter of ZF adsorbed Sr 2+ decreases. (authors)

87Sr/86Sr sourcing of ponderosa pine used in Anasazi great house construction at Chaco Canyon, New Mexico

Science.gov (United States)

Reynolds, Amanda C.; Betancourt, Julio L.; Quade, Jay; Patchett, P. Jonathan; Dean, Jeffery S.; Stein, John

2005-01-01

Previous analysis of 87Sr/86Sr ratios shows that 10th through 12th century Chaco Canyon was provisioned with plant materials that came from more than 75 km away. This includes (1) corn (Zea mays) grown on the eastern flanks of the Chuska Mountains and floodplain of the San Juan River to the west and north, and (2) spruce (Picea sp.) and fir (Abies sp.) beams from the crest of the Chuska and San Mateo Mountains to the west and south. Here, we extend 87Sr/86Sr analysis to ponderosa pine (Pinus ponderosa) prevalent in the architectural timber at three of the Chacoan great houses (Pueblo Bonito, Chetro Ketl, Pueblo del Arroyo). Like the architectural spruce and fir, much of the ponderosa matches the 87Sr/86Sr ratios of living trees in the Chuska Mountains. Many of the architectural ponderosa, however, have similar ratios to living trees in the La Plata and San Juan Mountains to the north and Lobo Mesa/Hosta Butte to the south. There are no systematic patterns in spruce/fir or ponderosa provenance by great house or time, suggesting the use of stockpiles from a few preferred sources. The multiple and distant sources for food and timber, now based on hundreds of isotopic values from modern and archeological samples, confirm conventional wisdom about the geographic scope of the larger Chacoan system. The complexity of this procurement warns against simple generalizations based on just one species, a single class of botanical artifact, or a few isotopic values.

BiCaSrCuO superconductors

International Nuclear Information System (INIS)

Polvi, V.M.; Niemi, K.J.

1989-01-01

BiCaSrCuO and BiPbCaSrCuO powders have been synthesized. Different research methods (SEM,EDS,XRF,SRD,DTA) have been used to characterize the bulk specimen and wires. Resistance and current density measured as a function of temperature are reported. The ceramic products contained several phases. Lead containing specimen gave the best results and the synthesis was easily reproducible

The dynamics of accumulation and disappearance of 89Sr in tea

International Nuclear Information System (INIS)

Chen Chuanqun; Wang Shouxiang; Zhang Yongxi; Sun Zhiming

1994-06-01

The 89 Sr was put into a tea tree-soil system by different ways. The results showed that for 89 Sr put into the system through the above-ground 1 part of tea tree, its concentration in tea was much higher than that through soil. The concentration of 89 Sr in older tea was higher than that in shoot for the same treatment. The accumulation and disappearance of 89 Sr in tea varied with the treatments. For the treatment through the above-ground part, the concentrations of 89 Sr in older tea and shoot were monotonously decreasing with time. For the treatment through soil the concentration of 89 Sr in shoot increased initially to a maximum value, then decreased slowly; while the concentration of 89 Sr in older tea increased quickly in a definite period, then increased slowly to gain a saturated value. In addition, the values of concentration factor of 89 Sr in the older tea and shoot were determined, too

Possible two-stage /sup 87/Sr evolution in the Stockdale Rhyolite

Energy Technology Data Exchange (ETDEWEB)

Compston, W.; McDougall, I. (Australian National Univ., Canberra. Research School of Earth Sciences); Wyborn, D. (Department of Minerals and Energy, Canberra (Australia). Bureau of Mineral Resources)

1982-12-01

The Rb-Sr total-rock data for the Stockdale Rhyolite, of significance for the Palaeozoic time scale, are more scattered about a single-stage isochron than expected from experimental error. Two-stage /sup 87/Sr evolution for several of the samples is explored to explain this, as an alternative to variation in the initial /sup 87/Sr//sup 86/Sr which is customarily used in single-stage dating models. The deletion of certain samples having very high Rb/Sr removes most of the excess scatter and leads to an estimate of 430 +- 7 m.y. for the age of extrusion. There is a younger alignment of Rb-Sr data within each sampling site at 412 +- 7 m.y. We suggest that the Stockdale Rhyolite is at least 430 m.y. old, that its original range in Rb/Sr was smaller than now observed, and that it experienced a net loss in Sr during later hydrothermal alteration at ca. 412 m.y.

Rb-Sr mantle isochrons from oceanic regions

Energy Technology Data Exchange (ETDEWEB)

Brooks, C; Hart, S R; Hofmann, A; James, D E [Carnegie Institution of Washington, D.C. (USA). Dept. of Terrestrial Magnetism

1976-09-01

Existing data for /sup 87/Sr//sup 86/Sr and Rb/Sr ratios of basalts from oceanic islands and mid-ocean spreading ridges show significant positive correlations on a Rb-Sr isochron diagram (when data are averaged by island group). Furthermore, tholeiites and alkali basalts occupy distinct non-overlapping fields on this plot. The tholeiite correlation is interpreted as a mantle isochron, and the agreement of this age (1.6+-0.2 b.y.) with that reported for Pb-Pb isochrons from oceanic basalts lends strong support to the use of such isochrons for tracing mantle evolution. Oceanic basalts are apparently sampling a mantle in which chemical heterogeneities have persisted for at least 1.5-2.0 b.y. The data support a kinematic model for the mantle in which a relatively uniform and non-radiogenic asthenosphere is penetrated by, and mixed with, blobs or plumes derived from an isolated (1.5-2 b.y.) and chemically heterogeneous mesosphere.

The initial 87Sr/86Sr ratios of the Kirwan Volcanics of Dronning Maud Land: Comparison with the Kirkpatrick Basalt, Transantarctic Mountains

International Nuclear Information System (INIS)

Faure, G.; Bowman, J.R.; Elliot, D.H.

1979-01-01

A series of lava flows from Mountain B (6 0 13.9'W, 74 0 06.9'S) of the Kirwan Escarpment in Dronning Maud Land, Antarctica, is composed of tholeiite basalts of Jurassic age. Their chemical compositions are similar to those of Jurassic basalts elsewhere in Dronning Maud Land but differ from those of the Kirkpatrick Basalt of the Transantarctic Mountains. The basalts on Mountain B contain 50.39% SiO 2 , 9.7 ppm Rb, 174.4 ppm Sr, have a Rb/Sr ratio of 0.057, and a K/Rb ratio of 417. Their average initial 87 Sr/ 86 Sr ratio is 0.7044 +- 0.0010 (1sigma) which suggests that the magma from which they formed could have been derived from the upper mantle without extensive contamination with 87 Sr and other elements. These results confirm earlier suggestions that the Jurassic basalts of Dronning Maud Land differ significantly from the Kirkpatrick Basalt and the Ferrar Dolerite of the Transantarctic Mountains. These differences in chemical and Sr-isotopic composition may be related to tectonic activity and magma formation during the break-up of Gondwanaland. (Auth.)

Understanding the apparent diffusivity of Sr-85 ion for MX-80 in different salinity condition at low dry density

International Nuclear Information System (INIS)

Ahmad Hasnulhadi Che Kamaruddin

2012-01-01

The apparent diffusivity of strontium-85 in the compacted MX-80 bentonite under different salinity conditions and dry densities was conducted were studied from the viewpoint of activation energy. Through in-diffusions experiments the effect of salinity on diffusion behavior of Sr-85 ions can also can be explained. As we know, Sr-90 is by product of the fission materials of nuclear wastes and should be manage properly. Sr-85 is radioactive isotope with the same chemical properties of Sr-90. Adsorption affects only non-steady-state diffusion while at the steady state (e.g., a constant concentration gradient between a constant source and a constant sink), there is no net uptake or release by adsorption, so adsorption has no effect on diffusion (Drever, James I., 1997). The changes in the basal spacing of bentonite as a function of salinity are needed to be observed by the X-ray diffraction method to understand the microstructure changes in diffusion pathways for Sr-85 in MX-80 bentonite. As we know, there could be three potential pathways for radionuclide diffusion in solution-saturated, compacted montmorillonite, i.e., pore water, external surfaces and the internal surface (interlayer spaces) of montmorillonite aggregates (Kozaki et al., 2008). So, it is important to understand the diffusion processes in term of apparent diffusivity of Sr-85 ions in different salinity concentration at low dry density of MX-80. Several parameters are needed in explaining the process such as dry density, activation energy, temperature dependence and concentration of the salinity solutions. (author)

Factor structure, reliability, and validity of the Japanese version of the Hoarding Rating Scale-Self-Report (HRS-SR-J

Directory of Open Access Journals (Sweden)

Tsuchiyagaito A

2017-05-01

Full Text Available Aki Tsuchiyagaito,1–3 Satoshi Horiuchi,4 Toko Igarashi,5 Yoshiya Kawanori,4 Yoshiyuki Hirano,1,3 Hirooki Yabe,2 Akiko Nakagawa1,3 1Research Center for Child Mental Development, Chiba University, Chiba, 2Department of Neuropsychiatry, Fukushima Medical University, Fukushima, 3United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Osaka, 4Faculty of Social Welfare, Iwate Prefectural University, Iwate, 5Graduate School of Education, Joetsu University of Education, Niigata, Japan Background: The Hoarding Rating Scale-Self-Report (HRS-SR is a five-item scale that assesses the symptoms of hoarding. These symptoms include excessive acquisition, difficulty in discarding, and excessive clutter that causes distress. We conducted three studies to examine the factor structure, reliability, and validity of the Japanese version of the HRS-SR (HRS-SR-J. Methods: Study 1 examined its reliability; 193 college students and 320 adolescents and adults completed the HRS-SR-J and, of the college students, 32 took it again 2 weeks later. Study 2 aimed to confirm that its scores in a sample of 210 adolescents and adults are independent of social desirability. Study 3 aimed to validate the HRS-SR-J in the aspects of convergent and discriminant validity in a sample of 550 adults. Results: The HRS-SR-J showed good internal consistency and 2-week test–retest reliability. Based on the nonsignificant correlations between the HRS-SR-J and social desirability, the HRS-SR-J was not strongly affected by social desirability. In addition, it also had a good convergent validity with the Japanese version of the Saving Inventory-Revised (SI-R-J and the hoarding subscale of the Obsessive-Compulsive Inventory, while having a significantly weaker correlation with the five subscales of the Obsessive-Compulsive Inventory, except for the hoarding subscale. In addition, the

Electronic structure of Ca, Sr, and Ba under pressure.

Science.gov (United States)

Animalu, A. O. E.; Heine, V.; Vasvari, B.

1967-01-01

Electronic band structure calculations phase of Ca, Sr and Ba over wide range of atomic volumes under pressure electronic band structure calculations for fcc phase of Ca, Sr and Ba over wide range of atomic volumes under pressure electronic band structure calculations for fcc phase of Ca, Sr and Ba over wide range of atomic volumes under pressure

The ternary post-transition metal carbodiimide SrZn(NCN)2

International Nuclear Information System (INIS)

Corkett, Alex J.; Konze, Philipp M.; Dronskowski, Richard

2017-01-01

SrZn(NCN) 2 , the first example of a ternary post-transition metal carbodiimide, was prepared by a solid-state metathesis reaction. The crystal structure was solved from PXRD data and found to adopt the orthorhombic (Cmcm) BaZnSO structure, a high symmetry modification of that expressed by the oxide analogue SrZnO 2 . Locally, SrZn(NCN) 2 features ZnN 4 tetrahedra and SrN 6 trigonal prisms similar to those in quarternary LiSr 2 M(NCN) 4 (M = Al 3+ and Ga 3+ ) phases, however, the overall topologies are distinct with single chains in the former and double chains in the latter. Electronic structure calculations indicate an indirect bandgap of about 2.95 eV in SrZn(NCN) 2 , slightly lower than the experimentally observed bandgap of 3.4 eV in SrZnO 2 and consistent with a greater degree of covalency. The structural similarities between SrZn(NCN) 2 and oxychalcogenide analogues highlight the pseudochalcogenide character of NCN 2- and suggest that the title compound may serve as a template for accessing novel ternary carbodiimides featuring tetrahedrally coordinated transition metals. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

878787Sr/868686Sr anomalies in Late Cretaceous-Early Tertiary ...

Indian Academy of Sciences (India)

paper documents the occurrences of two positive. 87. Sr/. 86 ... Analysis of trace elemental and stable isotopic profiles, sedimentation history ... et al (1980) and report of similar anomalies from ...... through the financial assistance of Alexander von. Humboldt ... and extinction events in earth history; Science 240. 996–1002.

Principles of μSR technics

International Nuclear Information System (INIS)

Chappert, J.

1983-05-01

Principles of muon spin rotation spectroscopy (μSR) are presented. Muons plus are only take into account because physical and chemical results obtained presently are obtained by them. Muon plus has two main characteristics when implanted in a sample: just, it can be considered as a interstitial site probe; then the muon plus can diffuse. Accordingly the quantities measured by μSR are a combination of static and dynamic properties of the muon plus and of the sample. A fluid characteristics is the possibility of munomium formation (μ + e - bound state) [fr

Ab initio investigations of the strontium gallium nitride ternaries Sr 3GaN3 and Sr6GaN5: Promising materials for optoelectronic

KAUST Repository

Goumri-Said, Souraya

2013-05-31

Sr3GaN3 and Sr6GaN5 could be promising potential materials for applications in the microelectronics, optoelectronics and coating materials areas of research. We studied in detail their structural, elastic, electronic, optical as well as the vibrational properties, by means of density functional theory framework. Both of these ternaries are semiconductors, where Sr3GaN3 exhibits a small indirect gap whereas Sr6GaN5 has a large direct gap. Indeed, their optical properties are reported for radiation up to 40 eV. Charge densities contours, Hirshfeld and Mulliken populations, are reported to investigate the role of each element in the bonding. From the mechanical properties calculation, it is found that Sr6GaN5 is harder than Sr3GaN3, and the latter is more anisotropic than the former. The phonon dispersion relation, density of phonon states and the vibrational stability are reported from the density functional perturbation theory calculations. © 2013 IOP Publishing Ltd.

The impact of Mg contents on Sr partitioning in benthic foraminifers

NARCIS (Netherlands)

Mewes, Antje; Langer, Gerald; Reichart, Gert Jan; de Nooijer, L.J.; Nehrke, Gernot; Bijma, Jelle

2015-01-01

Foraminiferal calcite Mg/Ca (Mg/CaCC) is used in paleoceanographic studies to reconstruct temperature. Furthermore, the Mg/CaCC is influenced by different seawater Mg/Ca (Mg/CaSW). Foraminiferal calcite Sr/Ca (Sr/CaCC) can potentially be used to reconstruct Sr/Ca ratios of seawater (Sr/CaSW). As

ATP Synthase β-Chain Overexpression in SR-BI Knockout Mice Increases HDL Uptake and Reduces Plasma HDL Level

Directory of Open Access Journals (Sweden)

Kexiu Song

2014-01-01

Full Text Available HDL cholesterol is known to be inversely correlated with cardiovascular disease due to its diverse antiatherogenic functions. SR-BI mediates the selective uptake of HDL-C. SR-BI knockout diminishes but does not completely block the transport of HDL; other receptors may be involved. Ectopic ATP synthase β-chain in hepatocytes has been previously characterized as an apoA-I receptor, triggering HDL internalization. This study was undertaken to identify the overexpression of ectopic ATP synthase β-chain on DIL-HDL uptake in primary hepatocytes in vitro and on plasma HDL levels in SR-BI knockout mice. Human ATP synthase β-chain cDNA was delivered to the mouse liver by adenovirus and GFP adenovirus as control. The adenovirus-mediated overexpression of β-chain was identified at both mRNA and protein levels on mice liver and validated by its increasing of DiL-HDL uptake in primary hepatocytes. In response to hepatic overexpression of β-chain, plasma HDL-C levels and cholesterol were reduced in SR-BI knockout mice, compared with the control. The present data suggest that ATP synthase β-chain can serve as the endocytic receptor of HDL, and its overexpression can reduce plasma HDL-C.

Physicochemical compatibility of SrCeO3 with potential SOFC cathodes

International Nuclear Information System (INIS)

Tolchard, J.; Grande, T.

2007-01-01

The chemical and physical compatibility of SrCeO 3 is investigated with respect to LaMO 3 (M=Mn, Fe, Co) and La 2-x Sr x NiO 4 (x=0, 0.8), via the reaction of fine-grained powder compacts and solid-state diffusion couples. Compositions were chosen so as to give predictive insight into possible candidate materials for all-oxide electrochemical devices. Results show the primary reaction in these systems to be the dissolution of SrO from SrCeO 3 into the LaMO 3 /La 2-x Sr x NiO 4 , and corresponding formation of La-doped CeO 2 . Reaction kinetics are observed to be relatively fast, with element profiles suggesting the diffusion of Sr 2+ in ceria to be surprisingly rapid. It is demonstrated that perovskite starting materials represent poor candidates for use with SrCeO 3 , reacting completely to form Ruddlesden-Popper/K 2 NiF 4 type oxides. Reaction with La 2 NiO 4 is less pronounced, and formation of secondary phases suppressed for the composition La 1.2 Sr 0.8 NiO 4 . It is thus concluded that Ruddlesden-Popper type oxides represent good candidate materials for use with a SrCeO 3 -based electrolytes when doped with appropriate levels of Sr. - Graphical abstract: Assessment of the SrCeO 3 proton conductor shows this material to have poor chemical compatibility with LaMO 3 perovskite systems, but predicts coexistence with Ruddlesden-Popper type oxides

Solidification of Bi2Sr2Ca1Cu2Oy and Bi2Sr1.75Ca0.25CuOy

International Nuclear Information System (INIS)

Holesinger, T.G.; Miller, D.J.; Viswanathan, H.K.; Chumbley, L.S.

1993-01-01

The solidification processes for the compositions Bi 2 Sr 2 CaCu 2 O y (2212) and Bi 2 Sr 1.75 Ca 0.25 CuO y (2201) were determined as a function of oxygen partial pressure. During solidification in argon, the superconducting phases were generally not observed to form for either composition. In both cases, the solidus is lowered to approximately 750 degree C. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 2-x Ca x O y (22x) and Cu 2 O while solidification of Bi 2 Sr 2 CaCu 2 O y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 3-x Ca x O y (23x) and Cu 2 O. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in O 2 resulted in large grains of 2201 interspersed with small regions containing the eutectic structure of 22x and CuO/Cu 2 O. Solidification of Bi 2 Sr 2 CaCu 2 O y in partial pressures of 1%, 20%, and 100% oxygen resulted in multiphase samples consisting of 2212, 2201, some alkaline-earth cuprates, and both divorced eutectic structures found during solidification in Ar. For both compositions, these latter structures can be attributed to oxygen deficiencies present in the melt regardless of the overpressure of oxygen. These eutectic structures are unstable and convert into the superconducting phases during subsequent anneals in oxygen. The formation process of the 2212 phase during solidification from the melt was determined to proceed through an intermediate state involving the 2201 phase

Sr isotope variations in the Carnian-Norian succession at Pizzo Mondello, Sicani Mountains, Sicily

Science.gov (United States)

Onoue, T.; Yamashita, K.; Rigo, M.; Abate, B.

2017-12-01

The Norian stage in the Late Triassic is exceptionally long (23 Myr) and was subdivided into three substages: the Lacian, Alaunian, and Sevatian. In order to infer the Norian environmental changes in the western Tethys Ocean, the stratigraphic variations of 87Sr/86Sr in the Upper Triassic limestone succession in Sicily were examined. The Pizzo Mondello section studied here mainly consists of a pelagic carbonate sequence of the Scillato Formation, and ranges in age from Tuvalian (late Carnian) to Rhaetian. The Scillato Formation represents a deep-water pelagic facies deposited along the Sicanian Basin in the western Tethys Ocean. We selected fine-grained limestone samples from both the microfacies of lime-mudstone and wackestone to approximate the primary 87Sr/86Sr signature of the limestone beds. The 87Sr/86Sr values are relatively constant in the Tuvalian and Lacian (early Norian). However, the remarkable rise in 87Sr/86Sr occurred across the Lacian-Alaunian (early-middle Norian) transition. Variations in 87Sr/86Sr values show an increasing trend in 87Sr/86Sr from 0.7077 at the base of Lacian to 0.7080 in the Sevatian (late Norian). In the Sevatian, the 87Sr/86Sr ratios display a sudden negative excursion toward lower values and show a relatively quick recovery to pre-excursion 87Sr/86Sr ratios. Korte et al. (2003) suggested that the rise in the 87Sr/86Sr values from the middle Carnian to the late Norian coincide with the Cimmerian orogeny. Our new 87Sr/86Sr data from the Pizzo Mondello section reveal a comparable trend, with a sharp increase in 87Sr/86Sr within the Alaunian, suggesting the rapid uplift and erosion in the Cimmerian Mountains at this time. The cause of the 87Sr/86Sr excursion in the Sevatian remains uncertain. However, the biostratigraphic record of conodonts suggests that a morphological evolution towards platform-less elements occurred with the beginning of the Sr-isotope excursion.

Inventory and vertical migration of {sup 90}Sr fallout and {sup 137}Cs/{sup 90}Sr ratio in Spanish mainland soils

Energy Technology Data Exchange (ETDEWEB)

Herranz, M. [Department Nuclear Engineering and Fluid Mechanics, University of the Basque, Country (UPV/EHU), Alda Urquijo s/n, E-48013 Bilbao (Spain); Romero, L.M. [CIEMAT, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Av. Complutense 22, 28040 Madrid (Spain); Idoeta, R. [Department Nuclear Engineering and Fluid Mechanics, University of the Basque, Country (UPV/EHU), Alda Urquijo s/n, E-48013 Bilbao (Spain); Olondo, C., E-mail: kontxi.olondo@ehu.es [Department Nuclear Engineering and Fluid Mechanics, University of the Basque, Country (UPV/EHU), Alda Urquijo s/n, E-48013 Bilbao (Spain); Valino, F. [CIEMAT, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Av. Complutense 22, 28040 Madrid (Spain); Legarda, F. [Department Nuclear Engineering and Fluid Mechanics, University of the Basque, Country (UPV/EHU), Alda Urquijo s/n, E-48013 Bilbao (Spain)

2011-11-15

In this paper the inventory of {sup 90}Sr in 34 points distributed along the Spanish peninsular territory is presented. Obtained values range between 173 Bq/m{sup 2} and 2047 Bq/m{sup 2}. From these data set and those {sup 137}Cs data obtained in a previous work the {sup 137}Cs/{sup 90}Sr activity ratio has been established, laying this value between 0.9 and 3.6. Also the migration depth of both radionuclides has been analysed obtaining for {sup 137}Cs an average value 57% lower than that obtained for {sup 90}Sr. Additionally, this paper presents the results obtained in 11 sampling points in which the activity vertical profile has been measured. These profiles have been analysed to state the behaviour of strontium in soils and after, by using a convective-diffusive model, the parameters of the model which governs the vertical migration of {sup 90}Sr in the soil, v (apparent convection velocity) and D (apparent diffusion coefficient) have been evaluated. Mean values obtained are 0.20 cm/year and 3.67 cm{sup 2}/year, respectively. - Highlights: > Measured {sup 90}Sr activity in Spanish mainland, being within a range of [173, 2047] Bq/m{sup 2}, with a mean value of 793 Bq/m{sup 2}. > Compared the migration capacity of {sup 137}Cs and {sup 90}Sr in the same soils. > {sup 90}Sr shows a unique behaviour tendency in soil. > The parameters which govern the applied model have been obtained for the analysed profiles. > Analysed those parameters' values also reflects this unique tendency.

Cs-137 and Sr-90 level in diary products

International Nuclear Information System (INIS)

Petukhov, V.L.; Dukhanov, Y.A.; Sevryuk, I.Z.; Patrashkov, S.A.; Korotkevich, O.S.; Gorb, T.S.; Petukhov, I.V.

2003-01-01

About 70% of radioactive substances fell on the territory of the Byelorussian Republic after the Chernobyl Atom Power Station Disaster. Cs-137 and Sr-90 accumulation dynamics was studied in milk of the cows from the highest polluted Braginsky area. 408 milk samples of Black and White cows were investigated. In 1995 average Cs-137 and Sr-90 levels were 61.00 and 3.73 Bk/dm 3 respectively. Cs-137 and Sr-90 levels exceeded Byelorussian Republic upper limits RDU - 96 in 10 and 50% of milk samples respectively. After 5 years (by 2000) Cs-137 and Sr-90 levels had become almost 3 and 2 times less (21.70 Bk/dm 3 and 1.72 Bk/dm 3 respectively). Cs-137 and Sr-90 levels exceeded RDU - 96 in 1.5 and 5.5% of milk samples respectively. In the same periods Cs-137 and Sr-90 levels were 7 and 2 times higher than the similar indexes in the relatively clean Novosibirsk area. Thus, radioactive element levels in milk of Black and White cows of the Byelorussian Republic decreased significantly for the past years. (authors)

Nonstoichiometry and stability in water of undoped SrCeO3

Directory of Open Access Journals (Sweden)

Jurado, J. R.

2003-10-01

Full Text Available Strontium cerate is the parent phase of an important class of proton-conducting perovskites with various potential technological applications. Phase formation and structure of SrCeO3 with Sr:Ce nonstoichiometry have been investigated for the series, Sr1±xCeO3±δ (0.98 ≤ x ≤ 1.04. Analyses by EPMA (electron probe micro analysis and X-ray diffraction (XRD indicate that, for samples sintered at 1350°C, the main phase is Sr-rich for all x. The accommodation of excess SrO in the bulk phase and/or intergranular regions is discussed. The stability of nominally stoichiometric SrCeO3 was examined in an atmosphere of high water vapour partial pressure (pH2O for 2 hours, degrading to Sr(OH2.H2O and CeO2 for pH2O ≥ 3.6atm.La fase SrCeO3 da origen a una importante familia de perovskitas conductoras protónicas con potenciales aplicaciones tecnológicas. En este trabajo se estudia la formación de la fase y la estructura de SrCeO3 con la relación Sr:Ce no estequiométrica para la serie Sr1±xCeO3±δ (0.98 ≤ x ≤ 1.04. Los análisis por microsonda (EPMA y difracción de rayos X (DRX indican que en las muestras sinterizadas a 1350°C, la fase principal es rica en estroncio para todo valor de x. Se discute la posible ubicación del exceso de SrO tanto en la región intergranular como en el propio grano. También se examina la estabilidad de la composición con estequiometría nominal SrCeO3 en una atmosfera con una alta presión de vapor de agua (pH2O, observándose que la degradación a Sr(OH2.H2O y CeO2 ocurre a pH2O ≥ 3.6atm (expuesto durante 2 horas.

Targeting SR-BI for cancer diagnostics, imaging and therapy

Directory of Open Access Journals (Sweden)

Maneesha Amrita Rajora

2016-09-01

Full Text Available Scavenger receptor class B type I (SR-BI plays an important role in trafficking cholesteryl esters between the core of high density lipoprotein and the liver. Interestingly, this integral membrane protein receptor is also implicated in the metabolism of cholesterol by cancer cells, whereby overexpression of SR-BI has been observed in a number of tumours and cancer cell lines, including breast and prostate cancers. Consequently, SR-BI has recently gained attention as a cancer biomarker and exciting target for the direct cytosolic delivery of therapeutic agents. This brief review highlights these key developments in SR-BI-targeted cancer therapies and imaging probes. Special attention is given to the exploration of high density lipoprotein nanomimetic platforms that take advantage of upregulated SR-BI expression to facilitate targeted drug-delivery and cancer diagnostics, and promising future directions in the development of these agents.

Internal friction around Tc connected with superconductivity in high Tc superconductors

International Nuclear Information System (INIS)

Wang Yening

1993-01-01

Internal friction and ultrasonic measurements show that there always exists a phase-like transition (PLT) characterized by the jump of lattice parameters at tens degrees above Tc in superconducting YBaCuO, BiSrCaCuO and TlBaCaCuO. Ferroelastic loops and shape memory effect associated with elastic softening invariably occur at the PLT temperature, showing the characteristics of thermoelastic martensitic transition. Internal frictions in KHz of Bi(Pb)SrCaCuO reveal a static hysteretic plateau (Qp -1 ) above Tc that drops linearly with temperature below Tc. The Qp -1 of YBaCuO decreases with decreasing oxygen content. The origin of the hysteretic Qp -1 is attributed to the lattice distortions around the carriers. (orig.)

Training effect of exchange bias in La0.67Sr0.33MnO3/SrTiO3 superlattice

International Nuclear Information System (INIS)

Zhu, S J; Zhao, B R; Xu, B; Zhu, B Y; Cao, L X; Qiu, X G

2008-01-01

The training effect of exchange bias has been observed in the superlattice consisting of ferromagnetic La 0.67 Sr 0.33 MnO 3 and non-magnetic SrTiO 3 layers. The exchange field shows an approximately power-law decrease with an increase in the number of hysteresis loop measurements. The vertical shift of the hysteresis loop reveals the existence of the net uncompensated spins at the interface between the La 0.67 Sr 0.33 MnO 3 and the SrTiO 3 layers. The irreversibility of magnetization measurements gives clear evidence that the interfacial spins will be frozen at low temperature. It is suggested that the frozen uncompensated spins at the interface are responsible for the shift of the hysteresis loop and the training effect of exchange bias might be a result of the relaxation process of those interfacial spins when the superlattice is consecutively field-cycled.

Back to the Future: International Education in Public Relations.

Science.gov (United States)

Sommerness, Martin D.; Beaman, Ronda

1994-01-01

Finds few offerings of university courses emphasizing international public relations across the United States, despite global trends underlining increased internationalization. Argues that individuals and organizations must take account of those trends to stay abreast of the changing environment. (SR)

Immune competence in /sup 90/Sr-exposed, adult thymectomized and antilymphocyteglobulin-treated CBA mice. Pt. 1. Allogenic skin graft reaction

Energy Technology Data Exchange (ETDEWEB)

Bierke, P.

1989-01-01

CBA mice subjected to either adult thymectomy, internal exposure to /sup 90/Sr or antilymphocyteglobulin treatment separately, or to combinations of the three were tested for cellular immune competence using their reaction to allogenic skin grafts. Peripheral blood white cell counts did not reveal any obvious correlation between the degree of mononuclear cell depletion and the ability to accept grafts, suggesting that the particular treatments depleted specific fractions of mononuclear cells, differing in their extent of involvement in the rejection process. No single treatment alone induced a significant prolongation in the time elapsed before graft rejection. Adult thymectomy followed by appropriate antilymphocyteglobulin treatment induced severe lymphocytopenia and a profound suppression of the cell-mediate immune system, as evidenced by the acceptance of allogenic skin grafts. When applied to /sup 90/Sr-preexposed mice the same treatment induced lifelong acceptance of grafts, indicating a similar, though weaker immunosuppressive impact of /sup 90/Sr. Hence it was possible to significantly enhance immunosuppression in /sup 90/Sr-exposed mice. This in vivo model should be useful when investigating the role of immunological responsiveness in radiation carcinogenesis. (orig.).

Sr isotope zoning in plagioclase from andesites at Cabo De Gata, Spai

DEFF Research Database (Denmark)

Waight, Tod Earle; Tørnqvist, Jakob

2018-01-01

Plagioclase crystals in andesites from the Cabo De Gata region show generally radiogenic Sr isotope compositions and consistent core to rim increases in 87Sr/86Sr that are indicative of open system processes in the lithosphere and crustal contamination during crystallization. High-grade metamorphic...... rocks of the Alpujárride and Nevado-Filábride complexes represent the most likely crustal contaminants. The plagioclases are characterized by subtly zoned and resorbed calcic cores (An73-86). These cores also have radiogenic 87Sr/86Sr (0.7127-0.7129), although less radiogenic than plagioclase rims......, groundmass plagioclase and whole rock compositions (up to 87Sr/86Sr = 0.7135). These cores are interpreted to represent early crystallization of plagioclase from hydrous melts emplaced into the lower crust. The parental melts to these andesites must therefore have already inherited their radiogenic Sr...

Cathode characterization system: preliminary results with (Ba,Sr,Ca) O coated cathodes

International Nuclear Information System (INIS)

Nono, M.C.A.; Goncalves, J.A.N.; Barroso, J.J.; Dallaqua, R.S.; Spassovsky, I.

1993-01-01

The performance of a cathode characterization system for studying the emission parameters of thermal electron emitters is reported. The system consists of vacuum chamber, power supplies and equipment for measuring and control. Measurements have been taken of the emission current as function of cathode temperature and anode voltage. Several (Ba, Sr) O coated cathodes were tested and the results have shown good agreement with Child's and Richardson's laws. The experimental work function is between 1.0 and 2.0 e V. All emission parameters measured are consistent with international literature data. (author)

Transfer of alkaline earth elements in mothers' milk and doses from 45Ca, 90Sr and 226Ra

International Nuclear Information System (INIS)

Smith, T.J.; Phipps, A.W.; Fell, T.P.; Harrison, J.D.

2003-01-01

An international programme of work is currently under way to develop methods for calculating doses to infants from ingestion of radionuclides present in mothers' milk. This paper considers the special case of the alkaline earth elements. Models have been developed for 45 Ca, 90 Sr and 226 Ra and the sensitivity of results to various changes in parameter values is discussed. A complication when calculating doses from intakes of radium is that the International Commission on Radiological Protection has previously recommended that doses from decay products of radium should be calculated using element-specific biokinetic models (so-called independent biokinetics). An extension of this method to the models for breastfeeding is proposed. Preliminary estimates of the doses received by the infant for a number of maternal intake scenarios show that doses to the infant can exceed the corresponding adult dose, such as for 45 Ca (ratio = 3.1) while, in other cases such as 90 Sr, the infant dose can be a significant fraction of the adult dose. (author)

87Sr/86Sr and 18O/16O ratios, interstitial water chemistry and diagenesis in deep-sea carbonate sediments of the Ontong Java Plateau

International Nuclear Information System (INIS)

Elderfield, H.; Oldfield, R.K.; Hawkesworth, C.J.

1982-01-01

Interstitial waters and sediments from DSDP sites 288 and 289 contain information on the chemistry and diagenesis of carbonate in deep-sea sediments and on the role of volcanic matter alteration processes. Sr/Ca ratios are species dependent in unaltered foraminifera from site 289 and atom ratios exceed those predicted by distribution coefficient data. During diagenesis Sr/Ca ratios of carbonates decrease and reach the theoretical distribution at a depth which is identical to the depth of Sr isotopic equilibration, where 87 Sr/ 86 Sr ratios of interstitial waters and carbonates converge. Mg/Ca ratios in the carbonates do not increase with depth as found in some other DSDP sites, possibly because of diagenetic re-equilibration with interstitial waters showing decreasing Mg 2+ /Ca 2+ ratios with depth due to Ca input and Mg removal by alteration of volcanic matter. Interstitial 18 O/ 16 O ratios increase with depth at site 289 to delta 18 O = 0.67 per thousand (SMOW), reflecting carbonate recrystallization at elevated temperatures, the first recorded evidence of this effect in interstitial waters. Interstitial Sr 2+ concentrations reach high levels, up to 1 mM, chiefly because of carbonate recrystallization. However, 87 Sr/ 86 Sr ratios decrease from 0.7092 to less than 0.7078, lower than for contemporaneous sea water, showing that there is a volcanic input of strontium at depth. (author)

Novel approaches for 90Sr analyses in contaminated environmental samples

International Nuclear Information System (INIS)

Kavasi, N.; Sahoot, S.K.; Area, H.; Aono, T.

2016-01-01

Radioactive strontium isotopes are generated with high cumulative fission yield (5-6 %) during thermal neutron fission in a nuclear reactor. The physical half-life of 89 Sr (50.52 d) is short but that of 90 Sr (28.8 y) is long enough to generate radioecological repercussions. 90 Sr has a long-lasting biological half-life (∼18 y) in the human body, due to its chemical similarity to calcium the importance of 90 Sr analysis is emphasized in case of a nuclear disaster. The world-wide spread of 90 Sr, as a background, is derived from the global atmospheric fallout contributed by large-scale atmospheric nuclear weapons tests conducted from 1945. In case of local contamination, nuclear accidents are not the only source of 90 Sr isotope, misconducted underground nuclear weapon tests; improper handling of by-products of nuclear weapon production or normal operation of nuclear facilities (e.g. reprocessing plants) can be taken into account

Effectiveness of Sr-binders tested using an in vitro model

International Nuclear Information System (INIS)

Hansen, Hanne S.; Eikelman, Margrethe; Hove, Knut

2008-01-01

Full text: The radioisotope 90 Sr is a fission product that in biological systems will behave like calcium and accumulate in bone. Because of the dose effect and the long biological half life of radiostrontium in humans the best countermeasure is to avoid absorption. Low levels of radiostrontium in food products are therefore necessary. To obtain food products, particularly milk, with low radiostrontium levels, the use of Sr-binders in animals may be required. We have tested a number of potential Sr-binders that may be used in animal production. Preliminary studies testing the Sr-binding effect of several compounds in goats demonstrated that only zeolite A(Na) and zeolite P would be of practical interest. Given at a rate of up to 30 g/d the Sr transfer to milk was reduced by 40%. However, because of the chemical properties of the zeolites, they may also bind other cations like Ca, Mg, Cu and Zn, all important minerals for animals. We have therefore tested the binding kinetics of Sr, Ca and Mg by the zeolites in rumen liquid from cows. We used 85 Sr to measure Sr binding and the stable elements of Ca and Mg naturally present in the rumen liquid to measure the binding of these minerals. In the rumen liquid mixture the pH was varied to simulate the pH variation in the digestive system of ruminants and the binding of the minerals to the zeolites were measured at each step. The time dependant 85 Sr binding showed that zeolite A(Na), at 0.5% in rumen liquid, pH 7.3, bound 98% of the 85 Sr already after 10 min. This proportion of Sr binding was persistent for the tested period of 24 h. The zeolite P at 0.5% in rumen liquid, pH 7.3, bound ca 85% and had a similar time dependant behavior. When pH was reduced to 2.5, similar to the pH in the abomasum, no Sr was bound to the zeolites. This was also the case at pH 3 and 4. At pH 5 ca 10% of the Sr was bound. Theses levels of pH simulated the conditions in the small intestine. To simulate the conditions in the large intestine

Electronic parameters of Sr2Nb2O7 and chemical bonding

DEFF Research Database (Denmark)

Atuchin, V.V.; Grivel, Jean-Claude; Korotkov, A.S.

2008-01-01

/2)) and Delta(O-Sr) = BE(O 1s)-BE(Sr 3d(5/2)), were used to characterize the valence electron transfer on the formation of the Nb-O and Sr-O bonds. The chemical bonding effects were considered on the basis of our XPS results for Sr2Nb2O7 and earlier published structural and XPS data for other Sr- or Nb...

Quenched Magnon excitations by oxygen sublattice reconstruction in (SrCuO 2) n /(SrTiO 3) 2 superlattices

NARCIS (Netherlands)

Dantz, M.; Pelliciari, J.; Samal, D.; Bisogni, V.; Huang, Y.; Olalde-Velasco, P.; Strocov, V. N.; Koster, G.; Schmitt, T.

2016-01-01

The recently discovered structural reconstruction in the cuprate superlattice (SrCuO 2) n /(SrTiO 3) 2 has been investigated across the critical value of n = 5 using resonant inelastic x-ray scattering (RIXS). We find that at the critical value of n, the cuprate layer remains largely in the

Precessional control of Sr ratios in marginal basins during the Messinian Salinity Crisis?

Science.gov (United States)

Topper, R. P. M.; Lugli, S.; Manzi, V.; Roveri, M.; Meijer, P. Th.

2014-05-01

Based on 87Sr/86Sr data of the Primary Lower Gypsum (PLG) deposits in the Vena del Gesso basin—a marginal basin of the Mediterranean during the Messinian Salinity Crisis—a correlation between 87Sr/86Sr values and precessional forcing has recently been proposed but not yet confirmed. In this study, a box model is set up to represent the Miocene Mediterranean deep basin and a connected marginal basin. Measurements of 87Sr/86Sr in the Vena del Gesso and estimated salinity extrema are used to constrain model results. In an extensive analysis with this model, we assess whether coeval 87Sr/86Sr and salinity fluctuations could have been forced by precession-driven changes in the fresh water budget. A comprehensive set of the controlling parameters is examined to assess the conditions under which precession-driven 87Sr/86Sr variations occur and to determine the most likely setting for PLG formation. Model results show that precession-driven 87Sr/86Sr and salinity fluctuations in marginal basins are produced in settings within a large range of marginal basin sizes, riverine strontium characteristics, amplitudes of precessional fresh water budget variation, and average fresh water budgets of both the marginal and deep basin. PLG deposition most likely occurred when the Atlantic-Mediterranean connection was restricted, and the average fresh water budget in the Mediterranean was significantly less negative than at present day. Considering the large range of settings in which salinities and 87Sr/86Sr fluctuate on a precessional timescale, 87Sr/86Sr variations are expected to be a common feature in PLG deposits in marginal basins of the Mediterranean.

Microstructure, mechanical properties, bio-corrosion properties and cytotoxicity of as-extruded Mg-Sr alloys

Energy Technology Data Exchange (ETDEWEB)

Zhao, Chaoyong [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); Pan, Fusheng, E-mail: fspan@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Chongqing Academy of Science and Technology, Chongqing 401123 (China); Zhang, Lei; Pan, Hucheng; Song, Kai; Tang, Aitao [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China)

2017-01-01

In this study, as-extruded Mg-Sr alloys were studied for orthopedic application, and the microstructure, mechanical properties, bio-corrosion properties and cytotoxicity of as-extruded Mg-Sr alloys were investigated by optical microscopy, scanning electron microscopy with an energy dispersive X-ray spectroscopy, X-ray diffraction, tensile and compressive tests, immersion test, electrochemical test and cytotoxicity test. The results showed that as-extruded Mg-Sr alloys were composed of α-Mg and Mg{sub 17}Sr{sub 2} phases, and the content of Mg{sub 17}Sr{sub 2} phases increased with increasing Sr content. As-extruded Mg-Sr alloy with 0.5 wt.% Sr was equiaxed grains, while the one with a higher Sr content was long elongated grains and the grain size of the long elongated grains decreased with increasing Sr content. Tensile and compressive tests showed an increase of both tensile and compressive strength and a decrease of elongation with increasing Sr content. Immersion and electrochemical tests showed that as-extruded Mg-0.5Sr alloy exhibited the best anti-corrosion property, and the anti-corrosion property of as-extruded Mg-Sr alloys deteriorated with increasing Sr content, which was greatly associated with galvanic couple effect. The cytotoxicity test revealed that as-extruded Mg-0.5Sr alloy did not induce toxicity to cells. These results indicated that as-extruded Mg-0.5Sr alloy with suitable mechanical properties, corrosion resistance and good cytocompatibility was potential as a biodegradable implant for orthopedic application. - Highlights: • Biodegradable as-extruded Mg-Sr alloys were fabricated. • Microstructure of alloys changed with increasing Sr content. • Mechanical properties of alloys could be controlled by adjusting the Sr content. • Corrosion properties of alloys decreased with increasing Sr content. • As-extruded Mg-0.5Sr alloy was potential for orthopedic application.

μ+SR Investigation of the Shastry-Sutherland Compound SrCu2(BO3)2

Science.gov (United States)

Sassa, Y.; Wang, S.; Sugiyama, J.; Amato, A.; Rønnow, H. M.; Rüegg, C.; Månsson, M.

In this study we have investigated the low-dimensional correlated spin system SrCu2(BO3)2 using ambient-pressure muon spin rotation/relaxation (μ+SR). The zero-field data are similar to previously published data, but in addition, they give an even clearer sign of the two low-temperature transitions (T1 ≈ 3 and T2 ≈ 7 K), which is fully consistent with inelastic neutron scattering (INS) measurements. Longitudinal field (LF) data clearly show that the copper spins are highly dynamic and a saturation of the low-temperature relaxation rate indicate that these are indeed two-dimensional (2D) quantum spin fluctuations.

Surface structural reconstruction of SrVO3 thin films on SrTiO3 (001)

Science.gov (United States)

Wang, Gaomin; Saghayezhian, Mohammad; Chen, Lina; Guo, Hangwen; Zhang, Jiandi

Paramagnetic metallic oxide SrVO3>(SVO) is an itinerant system known to undergo thickness-induced metal-insulator-transition (MIT) in ultrathin film form, which makes it a prototype system for the study of the mechanism behind metal-insulator-transition like structure distortion, electron correlations and disorder-induced localization. We have grown SrVO3 thin film with atomically flat surface through the layer-by-layer deposition by laser Molecular Beam Epitaxy (laser-MBE) on SrTiO3 (001) surface. Low Energy Electron Diffraction (LEED) measurements reveal that there is a (√2X √2) R45°surface reconstruction independent of film thickness. By using LEED-I(V) structure refinement, we determine the surface structure. In combination with X-ray Photoelectron Spectroscopy (XPS) and Scanning Tunneling Microscopy (STM), we discuss the implication on the MIT in ultrathin films below 2-3 unit cell thickness. This work is supported by the National Science Foundation under the NSF EPSCoR Cooperative Agreement No. EPS-1003897 with additional support from the Louisiana Board of Regents.

The coprecipitation of Sr2+ with calcite at 250C and 1 atm

International Nuclear Information System (INIS)

Pingitore, N.E. Jr.; Eastman, M.P.

1986-01-01

The incorporation of Sr 2+ into calcite at earth surface aqueous conditions is affected by the absolute concentration of Sr 2+ , the presence of Ba 2+ and NaCl in the solution and the rate of precipitation. At solution ratios (molar) of Sr 2+ to Ca 2+ in the low 10 -3 range, which yield calcites with several hundred ppm Sr 2+ , kappasub(calcite) sup(Sr) typically assumes a value between 0.10 and 0.20. Above these concentrations the value of kappasub(calcite) sup(Sr) drops to approximately 0.06. Furthermore, if minor amounts of Ba 2+ or large amounts of Na + (0.48 M) are added to a dilute Sr 2+ solution, a value around 0.06 for kappasub(calcite)sup(Sr) is found. This 'strontium concentration effect' and the associated 'competitive cation effect' suggest that small amounts of Sr 2+ may be incorporated into a limited number of nonlattice sites in calcite. Incorporation of Sr 2+ into these sites, presumably defects, noticeably affects kappasub(calcite)sup(Sr) only at low Sr 2+ concentrations and in the absence of competition from other large cations. An increase in kappasub(calcite)sup(Sr) with rate of precipitation, qualitatively similar to that found in other studies, was observed only when precipitation times were decreased from days to hours. For many geologic settings a partition coefficient for Sr 2+ into calcite of 0.06 appears appropriate, but there are situations - very low Sr 2+ concentrations, the presence of Mg 2+ , and fast precipitation rates - in which a larger value might better approximate natural partitioning. (author)

Carboniferous climate teleconnections archived in coupled bioapatite δ18OPO4 and 87Sr/86Sr records from the epicontinental Donets Basin, Ukraine

Science.gov (United States)

Montanez, Isabel P.; Osleger, Dillon J.; Chen, J.-H.; Wortham, Barbara E.; Stamm, Robert G.; Nemyrovska, Tamara I.; Griffin, Julie M.; Poletaev, Vladislav I.; Wardlaw, Bruce R.

2018-01-01

Reconstructions of paleo-seawater chemistry are largely inferred from biogenic records of epicontinental seas. Recent studies provide considerable evidence for large-scale spatial and temporal variability in the environmental dynamics of these semi-restricted seas that leads to the decoupling of epicontinental isotopic records from those of the open ocean. We present conodont apatite δ18OPO4 and 87Sr/86Sr records spanning 24 Myr of the late Mississippian through Pennsylvanian derived from the U–Pb calibrated cyclothemic succession of the Donets Basin, eastern Ukraine. On a 2 to 6 Myr-scale, systematic fluctuations in bioapatite δ18OPO4 and 87Sr/86Sr broadly follow major shifts in the Donets onlap–offlap history and inferred regional climate, but are distinct from contemporaneous more open-water δ18OPO4 and global seawater Sr isotope trends. A −1 to −6‰ offset in Donets δ18OPO4 values from those of more open-water conodonts and greater temporal variability in δ18OPO4 and 87Sr/86Sr records are interpreted to primarily record climatically driven changes in local environmental processes in the Donets sea. Systematic isotopic shifts associated with Myr-scale sea-level fluctuations, however, indicate an extrabasinal driver. We propose a mechanistic link to glacioeustasy through a teleconnection between high-latitude ice changes and atmospheric pCO2 and regional monsoonal circulation in the Donets region. Inferred large-magnitude changes in Donets seawater salinity and temperature, not archived in the more open-water or global contemporaneous records, indicate a modification of the global climate signal in the epicontinental sea through amplification or dampening of the climate signal by local and regional environmental processes. This finding of global climate change filtered through local processes has implications for the use of conodont δ18OPO4 and 87Sr/86Sr values as proxies of paleo-seawater composition, mean temperature, and glacioeustasy.

Carboniferous climate teleconnections archived in coupled bioapatite δ18OPO4 and 87Sr/86Sr records from the epicontinental Donets Basin, Ukraine

Science.gov (United States)

Montañez, Isabel P.; Osleger, Dillon J.; Chen, Jitao; Wortham, Barbara E.; Stamm, Robert G.; Nemyrovska, Tamara I.; Griffin, Julie M.; Poletaev, Vladislav I.; Wardlaw, Bruce R.

2018-06-01

Reconstructions of paleo-seawater chemistry are largely inferred from biogenic records of epicontinental seas. Recent studies provide considerable evidence for large-scale spatial and temporal variability in the environmental dynamics of these semi-restricted seas that leads to the decoupling of epicontinental isotopic records from those of the open ocean. We present conodont apatite δ18OPO4 and 87Sr/86Sr records spanning 24 Myr of the late Mississippian through Pennsylvanian derived from the U-Pb calibrated cyclothemic succession of the Donets Basin, eastern Ukraine. On a 2 to 6 Myr-scale, systematic fluctuations in bioapatite δ18OPO4 and 87Sr/86Sr broadly follow major shifts in the Donets onlap-offlap history and inferred regional climate, but are distinct from contemporaneous more open-water δ18OPO4 and global seawater Sr isotope trends. A -1 to -6‰ offset in Donets δ18OPO4 values from those of more open-water conodonts and greater temporal variability in δ18OPO4 and 87Sr/86Sr records are interpreted to primarily record climatically driven changes in local environmental processes in the Donets sea. Systematic isotopic shifts associated with Myr-scale sea-level fluctuations, however, indicate an extrabasinal driver. We propose a mechanistic link to glacioeustasy through a teleconnection between high-latitude ice changes and atmospheric pCO2 and regional monsoonal circulation in the Donets region. Inferred large-magnitude changes in Donets seawater salinity and temperature, not archived in the more open-water or global contemporaneous records, indicate a modification of the global climate signal in the epicontinental sea through amplification or dampening of the climate signal by local and regional environmental processes. This finding of global climate change filtered through local processes has implications for the use of conodont δ18OPO4 and 87Sr/86Sr values as proxies of paleo-seawater composition, mean temperature, and glacioeustasy.

75 FR 2915 - Self-Regulatory Organizations; International Securities Exchange, LLC; Order Approving a Proposed...

Science.gov (United States)

2010-01-19

... SECURITIES AND EXCHANGE COMMISSION [Release No. 34-61317; File No. SR-ISE-2009-103] Self-Regulatory Organizations; International Securities Exchange, LLC; Order Approving a Proposed Rule Change Relating to Market Data Fees January 8, 2010. I. Introduction On November 25, 2009, the International...

77 FR 4852 - Self-Regulatory Organizations; International Securities Exchange, LLC; Order Approving a Proposed...

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2012-01-31

... SECURITIES AND EXCHANGE COMMISSION [Release No. 34-66234; File No. SR-ISE-2011-82] Self-Regulatory Organizations; International Securities Exchange, LLC; Order Approving a Proposed Rule Change Relating to Legging Orders January 25, 2012. I. Introduction On November 29, 2011, the International Securities...

Methodological development for 87Sr/86Sr measurement in olive oil and preliminary discussion of its use for geographical traceability of PDO Nîmes (France).

Science.gov (United States)

Medini, Salim; Janin, Myriam; Verdoux, Patrick; Techer, Isabelle

2015-03-15

The lack of a geographical identification protocol for olive oils can lead to fraud and health risks. As some works call for Sr isotopes for the geographical identification of agri-food products, this study focus on the feasibility of extracting Sr from olive oils for isotopic measurements by TIMS. In fact, existing protocols for purification of Sr are unsuitable for lipid matrix. The defined protocol is applied to samples of PDO Nîmes olive oil. The accuracy of the extraction procedure is tested against isotopic standards. The values obtained are in conformity with NIST certified values. This consistency demonstrates that no modification of (87)Sr/(86)Sr ratio is brought about by this protocol. Consequently, the method is preliminary used on PDO Nîmes and Moroccan oils to evaluate the feasibility of a discriminant Sr signature on the two geographical products. This study provides promising results for the geographical discrimination and identification of PDO olive oils. Copyright © 2014 Elsevier Ltd. All rights reserved.

Photoluminescence study of Dy3+ doped SrCeVO5 phosphor

International Nuclear Information System (INIS)

Suresh, K.; Dai, Ch. Vijay Anil; Murthy, K.V.R.

2016-01-01

Dy 3+ doped SrCeVO 5 phosphor was synthesized by the solid-state reaction method. Photoluminescence (PL) technique was performed to characterize the sample. The excitation spectra monitored under 520 nm and 610 nm wavelength was characterized by a broad band ranging from 220-400 nm. From the excitation spectra two main bands at 265 nm and 325 nm were observed. The PLE intensity of 520 nm monitored shows high intensity than 610 nm spectrum. The emission spectra of SrCeVO 5 phosphor under excitations at 265 nm and 325 nm exhibited main peak at 515 nm (cyan) which is a strong, intense well resolved peak with FWHM (full width at half maximum) of 130 nm is observed. This emission is mainly may be due to Ce ion but not Dy ion. The same emission under 640 and 670 nm excitations (up conversion) with good intensity was also observed. Commission international de l'eclairage (CIE) co-ordinates under these excitations revealed that this phosphor emit cyan colour and could be used for the generation of white light in display and lamp devices. (author)