Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999  (773)
  • 1985-1989
  • 1935-1939
  • 1996  (773)
  • Engineering General  (686)
  • pharmacokinetics
  • 1
    Electronic Resource
    Electronic Resource
    Pharmacokinetics and toxicity of oral and intravenous lonidamine in dogs (1996)
    Springer
    Cancer chemotherapy and pharmacology 38 (1996), S. 129-135 
    Details
    ISSN: 1432-0843
    Keywords: Key words lonidamine ; pharmacokinetics ; dog
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Plasma lonidamine concentration and toxicity were investigated in dogs receiving 100, 200, 400, 800, 1200 mg/m2 orally twice daily for 30 days and in dogs receiving single intravenous doses of 200, 400, 800, 1200 mg/m2. Physical or laboratory signs of toxicity were not observed in dogs receiving oral lonidamine, but severe vomiting and signs of acute hepatic and pancreatic toxicity were observed in dogs receiving intravenous doses that exceeded 400 mg/m2. The area under the lonidamine concentration versus time curve (AUC) in dogs receiving 200, 400, and 800 mg/m2 of lonidamine intravenously was a 1.8-, 3.3-, and 8.7-fold higher than in dogs receiving oral lonidamine. This suggests that the bioavailability of oral lonidamine may be limited. However, centrilobular hepatocellular swelling and vacuolation were observed in dogs receiving oral lonidamine. Serum alanine aminotransferase (ALT) activity was increased in dogs receiving intra-venous lonidamine. These findings suggest that lonidamine is hepatotoxic in dogs. However, serum ALT was increased in only 1/4 dogs receiving 400 mg/m2 of lonidamine intravenously and plasma concentration were within the range capable of sensitizing hyperthermia and chemotherapy. Therefore, this dose and route appears to be a viable and controllable method for prospective quantification of lonidamine interaction with systemic chemotherapy and/or hyperthermia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002800050460
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of dexamethasone in premature neonates (1996)
    Springer
    European journal of clinical pharmacology 49 (1996), S. 477-483 
    Details
    ISSN: 1432-1041
    Keywords: Dexamethasone ; Premature neonates ; pharmacokinetics ; bronchopulmonary dysplasia ; infant ; newborn
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: Dexamethasone is frequently used in premature neonates with bronchopulmonary dysplasia, however little is known about its disposition in this population. Methods: We evaluated the pharmacokinetics of dexamethasone in 9 premature neonates with a mean gestational age of 27.3 weeks and a postnatal age of 21.8 days. Results: There was a strong relationship between clearance (4.96 ml·min−1·kg−1) and gestational age (r=0.884). Pharmacokinetic parameters were grouped based on a gestational age of less than 27 weeks (Group I) and greater than 27 weeks (Group II). Mean clearance in group I and group II was 1.69 and 7.57 ml·min−1·kg−1, respectively. Mean distribution volume in group I and II was 1.26 and 2.19 l·kg−1, respectively. No significant relationships were noted between the disposition of dexamethasone and ventilator requirements or adverse effects. Conclusion: The pharmacokinetics of dexamethasone in premature neonates was related to gestational age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195934
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Influence of food on the bioavailability and some pharmacokinetic parameters of diprafenone – a novel antiarrhythmic agent (1996)
    Springer
    European journal of clinical pharmacology 50 (1996), S. 315-319 
    Details
    ISSN: 1432-1041
    Keywords: Key words Diprafenone; antiarrhythmics ; bioavailability ; human ; foods ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The present study was done to investigate the effect of food on the bioavailability of diprafenone. Methods: The most important pharmacokinetic parameters (Cmax, t1/2, AUC) and the relative oral availability of a solid oral preparation of racemic diprafenone were investigated when administered to fasting subjects and 10 min after a standard meal, in an open, randomised, crossover trial. Single oral doses of 100 mg were given on two different occasions, at least 1 week apart. The serum concentrations of diprafenone and its hydroxy-metabolite were determined up to 24 hours after administration by a sensitive, specific HPLC method. Fifteen healthy, male volunteers were enrolled in the trial. Their mean height, weight and age were 183 cm, 80 kg and 22 years, respectively. Fourteen volunteers were found to be rapid hydroxylators and one was a slow hydroxylator of debrisoquine. Only data from the rapid hydroxylators were used in the statistical analysis. Results: Food increased the oral bioavailability of diprafenone by approximately 50%. This effect was similar in rapid and in slow hydroxylators. The only slow hydroxylator in this trial had an AUC0–last ratio (with food/fasting) of 1.54. These findings suggest that diprafenone should be administered in a constant temporal relationship to food.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050115
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    A single dose of ursodiol does not affect cyclosporine absorption in liver transplant patients (1996)
    Springer
    European journal of clinical pharmacology 50 (1996), S. 335-337 
    Details
    ISSN: 1432-1041
    Keywords: Key words Cyclosporine ; Ursodiol; ursodeoxycholic acid ; absorption ; pharmacokinetics ; liver transplantation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: To study the possible influence of ursodiol (ursodeoxycholic acid), a hydrophilic bile acid, on cyclosporine (CsA) bioavailability. Methods: Seven adult liver transplant recipients participated in a randomised cross-over pharmacokinetic study comparing ursodiol (600 mg) with placebo in single doses. Blood concentrations of CsA were measured by HPLC. Results: There was no significant effect of ursodiol on CsA absorption: AUC was 5011 vs 5486 ng⋅h⋅ml–1, Cmax was 832 vs 871 ng⋅ml–1 and tmax was 2 vs 2 h, after ursodiol and placebo, respectively. Conclusion: Although a significant period effect was observed, we conclude that a single dose of ursodiol has little effect on CsA absorption in liver transplant patients and that an interaction in the intestinal lumen between these two drugs is unlikely.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050118
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Absolute bioavailability of fluoride from disodium monofluorophosphate and enteric-coated sodium fluoride tablets (1996)
    Springer
    European journal of clinical pharmacology 50 (1996), S. 321-326 
    Details
    ISSN: 1432-1041
    Keywords: Key words Sodium fluoride ; Disodium monofluorophosphate; absolute bioavailability ; pharmacokinetics ; elderly population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objectives: The absolute bioavailability and other pharmacokinetic parameters of two fluoride formulations were investigated in 13 healthy volunteers, aged 61–70 years. Methods: The following formulations were administered, under fasting conditions, in a single-dose three-way cross-over design: tablets of 76 mg disodium monofluoro phosphate (MFP, equivalent to 10.0 mg F− ion), enteric-coated (e.c.) tablets of 25 mg sodium fluoride (NaFor, equivalent of 11.3 mg F− ion), and an isoosmotic aqueous injection solution (4 ml) of 22.1 mg sodium fluoride (NaFiv, equivalent of 10.0 mg F− ion). There was a wash-out period of at least one week between each administration. Blood was sampled before and during a 24-hour period after administration. For F− excretion urine was sampled 48 hours before (baseline) and over the 48 hours after the adminstration. Results: The mean t1/2 values of the three formulations were 8.3, 8.7 and 8.3 h for MFP, NaFor and NaFiv respectively, and were not significant different. Mean Cmax after MFP was significantly higher than after NaFor [344 vs 142 μg⋅l−1]. Mean tmax for MFP was shorter than for NaFor [1.1 vs 4.6 h]. MFP had significantly higher bioavailability [102.8%] than NaFor [64.2%]. Conclusion: The MFP formulation showed higher bioavailability with smaller variation than the NaFor formulation. MFP is preferable, therefore, for fluoride therapy in clinical practice, and changing from NaFor to MFP will require adjustment of the dose.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050116
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Single oral doses of amisulpride do not enhance the effects of alcohol on the performance and memory of healthy subjects (1996)
    Springer
    European journal of clinical pharmacology 51 (1996), S. 161-166 
    Details
    ISSN: 1432-1041
    Keywords: Key words Amisulpride; ethanol vector ; performance ; memory ; cognitive function ; interaction ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objectives: Amisulpride is a benzamide antipsychotic that binds selectively to dopamine D2- and D3-receptors, preferentially in limbic and hippocampal structures. Since other substituted benzamides have a limited or negligible interaction with alcohol on human performance, amisulpride was studied for this potential. Methods: In a randomised double-blind crossover study, 18 young, non-smoking men took single oral doses of placebo and amisulpride 50 mg and 200 mg, without and with ethanol (0.8 g ⋅kg−1) taken 30 min later. Objective performance tests and self-ratings were done at baseline and 1.5, 3.5 and 6.5 h after drug intake. Memory (immediate and delayed recall) was tested 2 h after dosing. Breath ethanol and the plasma concentrations of amisulpride and prolactin were measured. Three-way ANOVA + Newman-Keul tests were used for statistical analyses; interactions were confirmed by factorial contrast ANOVA. Results: Mean blood ethanol was 0.94, 0.62 and 0.26 g ⋅l−1 at the three test times. It produced significant impairment in all performance tests (symbol digit substitution, simulated driving, body sway, flicker fusion, tapping, nystagmus), reduced both immediate and delayed recall in memory tests, and caused subjective clumsiness, muzziness and mental slowness, mainly between 1.5 to 4.5 h after dosing. Amisulpride, 50 and 200 mg elevated plasma prolactin but had minimal or no effect on performance, attention and memory. The decreases in immediate free recall after the 50 mg dose and in delayed free recall after the 200 mg dose were slight. Amisulpride neither modified blood ethanol concentrations nor enhanced the detrimental effect of ethanol on skilled and cognitive performance; it slightly antagonised ethanol in the digit copying test. Ethanol did not modify the effect of amisulpride on plasma prolactin, and the plasma concentrations of amisulpride were little changed by ethanol. Conclusions: Amisulpride in single oral doses of 50 and 200 mg did not interact significantly with the effects of high, moderate or low concentrations of ethanol on human skilled and cognitive performance. The drugs did interact pharmacokinetically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050178
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Comparison between concentrations of racemic mefloquine, its separate enantiomers and the carboxylic acid metabolite in whole blood serum and plasma (1996)
    Springer
    European journal of clinical pharmacology 51 (1996), S. 171-173 
    Details
    ISSN: 1432-1041
    Keywords: Key words Mefloquine; mefloquine enantiomers ; carboxylic acid metabolite ; blood concentrations ; pharmacokinetics ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: To compare concentrations of the separate enantiomers of mefloquine (MQ), total racemic MQ and the carboxylic acid metabolite in different blood fractions at steady state. Setting: Human volunteer laboratory, Unit of Clinical Pharmacology, Karolinska Institute. Volunteers: Ten healthy adult Caucasian volunteers. Methods: Drug concentrations were determined by high-performance liquid chromatography (HPLC). Results: Trough concentrations of the (+)RS enantiomer were higher in venous whole blood than in plasma and serum (mean ratios, 1.41 and 1.38). For the other enantiomer, (−)SR, concentrations were lower in whole blood than in plasma (mean ratio 0.89) and for the metabolite this ratio was 0.5. Conclusion: Stereoselective distribution might be important for antimalarial activity and should be considered when pharmacokinetic studies are performed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050180
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Effect of grapefruit juice on the pharmacokinetics of amlodipine in healthy volunteers (1996)
    Springer
    European journal of clinical pharmacology 51 (1996), S. 189-193 
    Details
    ISSN: 1432-1041
    Keywords: Key words Dihydropyridine ; Amlodipine ; Grapefruit juice; flavonoids ; interaction ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract. Objective: This study was performed to assess whether coadminstration with grapefruit juice significantly affects the pharmacokinetics of amlodipine, a dihydropyridine class calcium antagonist with slow absorption, distribution and low plasma clearance. The primary objective was to evaluate whether short exposure to grapefruit juice could affect the metabolism of amlodipine to an extent similar to that previously demonstrated for other dihydropyridines (e.g. felodipine, nisoldipine, nitrendipine). Methods: Twelve healthy male volunteers followed a randomised, open crossover study design, comparing the effect of a single oral dose of amlodipine (5 mg) taken together with a glass of grapefruit juice (250 ml) vs water. Blood samples to determine plasma concentration were taken and blood pressure (BP) and heart rate (HR) were measured throughout the study. Results: When amlodipine was coadministered with grapefruit juice, Cmax was 115% and AUC(0–72 h) was 116% compared with water, but tmax was not significantly changed. There were no significant differences in BP and HR between the two treatments. A small decrease in diastolic BP, however, was observed in both treatments 4–8 h after drug administration, coinciding with Cmax, but this was normalised after 12 h. The BP reduction seen was compensated by a slight increase in HR, which remained throughout the study. Conclusion: An interaction between grapefruit juice and amlodipine was demonstrated. The haemodynamic data showed that a dose of 5 mg was sufficient to achieve a BP reduction in healthy subjects, but the increase in amlodipine plasma concentration seen after intake of grapefruit juice was too small to significantly affect BP or HR. The clinical significance of this food/drug interaction, however, cannot be ignored since there is considerable variation between individuals and a more extensive intake of grapefruit juice might give more pronounced effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050183
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Effects of heat exposure in a Finnish sauna on the pharmacokinetics and metabolism of midazolam (1996)
    Springer
    European journal of clinical pharmacology 51 (1996), S. 335-338 
    Details
    ISSN: 1432-1041
    Keywords: Key words Midazolam ; Sauna; metabolism ; pharmacokinetics ; heat ; pharmacodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The effect of short-term heat exposure in a Finnish sauna on hepatic first-pass metabolism and the capacity to metabolize midazolam were studied in a crossover trial. Midazolam oral (15 mg) and intravenous (0.05 mg ⋅ kg−1) was given to 6 healthy young male volunteers, in random order, during a control session and a sauna bathing session (temperature 85–100° C, relative humidity 25–30%). Blood samples for the determination of plasma midazolam and α-hydroxy midazolam concentrations were taken for 6 h after drug administration. Results: After oral administration, the bioavailability and clearance of midazolam were not affected by sauna bathing, nor was there a significant difference in α-hydroxy midazolam plasma concentration or the α-hydroxy midazolam/midazolam AUC-ratio between the sessions. Midazolam Cmax was increased and its t1/2β was prolonged during the sauna session, but the clinical relevance of the findings appears to be modest. The pharmacokinetics of intravenous midazolam were not affected by sauna bathing. Conclusions: Short-term heat exposure may not affect the first-pass metabolism or hepatic capacity to metabolize midazolam.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050208
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Therapeutic monitoring of nalbuphine: transplacental transfer and estimated pharmacokinetics in the neonate (1996)
    Springer
    European journal of clinical pharmacology 49 (1996), S. 485-489 
    Details
    ISSN: 1432-1041
    Keywords: Key words Nalbuphine ; Neonate; therapeutic drug monitoring ; placental transfer ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Nalbuphine, a mixed agonist-antagonist opiate, is commonly used as a systemic analgesic during labour. Recent reports of perinatal adverse effects prompted us to carry out therapeutic nalbuphine monitoring in obstetric analgesia. Because data on fetomaternal transfer are scarce and the pharmacokinetics of this drug in the neonate are largely unknown, we report data obtained from 28 parturients treated with nalbuphine either intramuscularly and/or intravenously during labour. Plasma nalbuphine levels were measured by high-performance liquid chromatography (HPLC) with electrochemical detection. At delivery, 30–150 min after maternal administration, nalbuphine concentrations ranged from 5.0 to 79.2 ng ⋅ ml−1 in mother plasma samples and from 3.0 to 46.6 ng ⋅ ml−1 in umbilical cord plasma samples. Nalbuphine concentrations were highly correlated to dose. The fetomaternal ratio was high: 0.74 and not correlated to the administered dose of nalbuphine. An estimated plasma half-life of 4.1 h was calculated from two determinations in the neonate based on the assumption of a monoexponential decay of nalbuphine concentrations. Apart from a flattening of the fetal heart rate tracing in 54% of the cases, only one neonate had a low Apgar score at birth. The apparent prolonged half-life of nalbuphine in the neonate indicates the usefulness of an intramuscular injection of naloxone to prevent recurrence of cardiorespiratory depression due to nalbuphine administration to the mother.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050054
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Bioavailability of 1-deamino-8-D-arginine vasopressin with an enzyme inhibitor (aprotinin) from the small intestine in healthy volunteers (1996)
    Springer
    European journal of clinical pharmacology 50 (1996), S. 491-495 
    Details
    ISSN: 1432-1041
    Keywords: Key words Aprotinin ; Arginine vasopressin; bioavailability ; dDAVP ; enzyme inhibitor ; gastrointestinal tract ; healthy volunteer ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The bioavailability of an aqueous solution of 1-deamino-8-D-arginine vasopressin (dDAVP), with and without an enzyme inhibitor, was studied in six healthy, male volunteers aged 19–34 years, followed for 8 h after each drug administration. Methods: For i.v. administration the subjects received 4 μg dDAVP. For intestinal administration 500 μg dDAVP was administered directly, in two separate sessions, in the first part of the duodenum via a triple-lumen channel tube. In one session a solution of isotonic polyethylene glycol (PEG) was given as a continuous enteral perfusion. In the other session a solution of PEG and aprotinin was administered enterally at the constant rate of 5 ml⋅min−1 for 4 h. Plasma dDAVP was measured using a specific, sensitive radioimmunoassay and intestinal juice was collected for measurement of lipase, chymotrypsin and pH every 30 min for 5 h. Results: The intestinal chymotrypsin activity was decreased after perfusion of aprotinin while the lipase activity was not modified. After i.v. administration, the half-life of elimination of dDAVP was 1.56 h and plasma clearance 1.24 ml⋅min⋅kg−1. The mean bioavailability after duodenal administration of dDAVP + aprotinin was 0.46% compared with 0.09% after duodenal administration of dDAVP alone. The bioavailability of dDAVP after direct duodenal administration of an aqueous solution was similar to that after swallowing a tablet in a previous study and increased 5 times when given together with a perfusion of an enzyme inhibitor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050146
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Multiple dose pharmacokinetics of tiludronate in healthy volunteers (1996)
    Springer
    European journal of clinical pharmacology 51 (1996), S. 175-181 
    Details
    ISSN: 1432-1041
    Keywords: Key words Tiludronate; healthy volunteers ; bisphosphonates ; pharmacokinetics ; calcium metabolism ; bone resorption ; adverse events
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objectives: A double-blind, placebo-controlled study was conducted to assess the pharmacokinetics and pharmacodynamics of the bisphosphonate tiludronic acid, administered once daily as sodium tiludronate 200, 400, 600 and 800 mg for 12 days. Four groups of ten subjects participated in the study, with a drug to placebo ratio of 4:1. Methods: Pre-dose blood samples were taken on alternate days, starting on Day 1 and additional samples were collected over 144 h following the final dose on Day 12. Urine was collected over 24 h after the final dose. Indices of calcium homeostasis and biochemical markers of bone turnover were assessed during the study as pharmacodynamic parameters. Tolerability was evaluated with special emphasis on renal function and gastrointestinal irritation. Adverse experiences were assessed at regular time intervals. Results and conclusions: Steady state was attained from Day 4 (200 mg) or from Day 6 (400, 600 and 800 mg). Following the final dose on Day 12, minimal plasma concentrations (Cmin) ranged between 0.19 and 1.5 mg ⋅ l−1, and maximal plasma concentrations (Cmax) between 1.1 and 7.8 mg⋅l−1 for the lowest and highest doses, respectively. A supra-proportional increase in Cmax, AUC24 and Ae 24 with dose was observed. There was a linear relationship between the plasma tiludronic acid and its urinary excretion rate, so, the disproportional rise in Cmax and AUC24 with increasing dose could not be attributed to saturation of renal excretion. Certain indices of calcium homeostasis changed significantly during the study, but generally, became only prominent at the highest dose level of 800 mg. Total serum calcium and the urinary calcium/creatinine clearance ratio fell, indicating depression of osteoclastic bone resorption, which was not revealed by serum osteocalcin levels probably because of the brevity of the treatment (12 days). In response to the decline in serum calcium, serum 1,25-dihydroxyvitamin D3 and intact PTH (1–84) levels increased. None of the safety parameters raised any concerns about the safety of sodium tiludronate administered in this way.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050181
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Haemodynamic effects and pharmacokinetics of oral d-and l-nebivolol in hypertensive patients (1996)
    Springer
    European journal of clinical pharmacology 51 (1996), S. 259-264 
    Details
    ISSN: 1432-1041
    Keywords: Key words Nebivolol ; Hypertension; d ; l-enantiomers ; pharmacokinetics ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: Nebivolol is a selective β1-adrenergic receptor blocker possessing an ancillary vasodilating effect. The objective of the present study was to study the haemodynamic and pharmacokinetic properties of nebivolol 5 mg once daily in a double-blind, placebo-controlled cross-over study. Methods: Fifteen patients, 12 men and 3 women, with essential hypertension were investigated. Blood pressure and peripheral circulation were determined after acute oral nebivolol administration, 5 mg daily, and after 4 weeks treatment. Results: The acute effect on blood pressure upon single-dosing was weak and non-significant. After 4 weeks both systolic blood pressure (152 vs 163 mmHg) and diastolic blood pressure (89 vs 97 mmHg) were significantly reduced after nebivolol treatment as compared to placebo. Following the first dose the venous volume was higher on placebo (5.88 ml ⋅ 100 ml−1 tissue) as compared to active nebivolol treatment (5.17 ml ⋅ 100 ml−1 tissue), while there were no statistically significant differences with regard to venous plethysmographic findings after 1 month on placebo (5.53 ml ⋅ 100 ml−1 tissue) or on active treatment (5.97 ml ⋅ 100 ml−1 tissue). Calculated peripheral resistance did not differ between active treatment (617 units) or placebo (548 units) after the first dose, whereas it was significantly lowered after 4 weeks of nebivolol treatment (483 units) as compared to placebo (593 units). Conclusions: Oral nebivolol 5 mg once daily lowered blood pressure and heart rate during steady state compared to placebo. Moreover, venous volume was reduced during acute but not steady-state dosing, while peripheral resistance was unaffected in the acute phase but reduced during steady state. Plasma concentrations of the separate enantiomers plus hydroxylated metabolites after the first and last dose in hypertensive patients were similar to those in healthy subjects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050194
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Lack of pharmacodynamic and pharmacokinetic interaction between pantoprazole and phenprocoumon in man (1996)
    Springer
    European journal of clinical pharmacology 51 (1996), S. 277-281 
    Details
    ISSN: 1432-1041
    Keywords: Key words Pantoprazole; Proton pump inhibitor drug interaction ; oral anticoagulant phenprocoumon ; pharmacodynamics ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: Pantoprazole is a selective proton pump inhibitor characterized by a low potential to interact with the cytochrome P450 enzymes in man. Due to the clinical importance of an interaction with anticoagulants, this study was carried out to investigate the possible influence of pantoprazole on the pharmacodynamics and pharmacokinetics of phenprocoumon. Methods: Sixteen healthy male subjects were given individually adjusted doses of phenprocoumon to reduce prothrombin time ratio (Quick method) to about 30–40% of normal within the first 5–9 days and to maintain this level. The individual maintenance doses remained unaltered from day 9 on and were administered until day 15. Additionally, on study days 11–15, pantoprazole 40 mg was given per once daily. As a pharmacodynamic parameter, the prothrombin time ratio was determined on days 9 and 10 (reference value) and on days 14 and 15 (test value), and the ratio test/reference was evaluated according to equivalence criteria. Results: The equivalence ratio (test/reference) for prothrombin time ratio was 1.02 (90% confidence interval 0.95–1.09), thus fulfilling predetermined bioequivalence criteria (0.70–1.43). The pharmacokinetic characteristics AUC0–24h and Cmax of S(−)-and R(+)-phenprocoumon were also investigated using equivalence criteria. Equivalence ratios and confidence limits of AUC0–24h and of Cmax of S(−)-phenprocoumon (0.93, 0.87–1.00 for AUC0–24h; 0.95, 0.88–1.03 for Cmax) and of R(+)-phenprocoumon (0.89, 0.82–0.96; 0.9, 0.83–0.98) were within the accepted range of 0.8–1.25. Conclusion: Pantoprazole does not interact with the anticoagulant phenprocoumon on a pharmacodynamic or pharmacokinetic level. Concomitant treatment was well tolerated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050198
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Bioavailability of estradiol from a new matrix and a conventional reservoir-type transdermal therapeutic system (1996)
    Springer
    European journal of clinical pharmacology 51 (1996), S. 327-330 
    Details
    ISSN: 1432-1041
    Keywords: Key words Hormone replacement therapy; estradiol ; pharmacokinetics ; bioequivalence ; postmenopausal volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: Bioavailability of estradiol delivered from a newly developed matrix-type transdermal therapeutic system (MTTS) was compared with that of the conventional reservoir-type system (RTTS). Both formulations have a nominal delivery rate of 50 μg per day of 17β-estradiol (E2). Plasma concentrations of E2 and estrone (E1) were determined at steady state during a 96-h application of each formulation to 34 postmenopausal volunteers, using a two-stage randomized two-period crossover design. Results: The MTTS proved to be equivalent to the RTTS with respect to the extent of E2 absorption. Due to differences in patch design and composition, the rate of absorption was different between the two systems, with less fluctuating E2 plasma levels during application of the matrix system. Local tolerability and adhesion of MTTS appeared to be better than those of the reservoir system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050206
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Rectal pharmacokinetics of budesonide (1996)
    Springer
    European journal of clinical pharmacology 49 (1996), S. 293-298 
    Details
    ISSN: 1432-1041
    Keywords: Key words Budesonide; enema ; pharmacokinetics ; healthy subjects ; hepatic bypass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The pharmacokinetics and systemic availability of budesonide after rectal administration of two single enema doses (2 mg in 100 ml fluid of almost identical composition) were compared in 15 healthy volunteers. In 11 of these subjects, 2 mg oral budesonide in a gelatine capsule was given on a separate occasion. An intravenous administration (0.5 mg) was given as reference. With this design, individual hepatic bypass of the rectally administered budesonide dose could be estimated. The pharmacokinetics of the two enema formulations were similar, although not bioequivalent. Mean systemic availability was 16% (range 4.2–43%) and 15% (3.2–50%) after rectal administration and 6.3% (2.4–10%) after oral administration. The rectal data revealed a small intra- but a substantial inter-subject variability in systemic availability. Cmax was 3.3 nmol ⋅ l−1 (0.95–8.2), 3.0 nmol ⋅ l−1 (0.64–8.9) and 1.3 nmol ⋅ l−1 (0.61–3.0), respectively, for the three formulations. Absorption was rapid and essentially terminated within 3 h after rectal dosing [tmax = 1.3 h for both formulations (range 0.5–2.0)], but was slower after oral dosing [tmax = 2.1 h (1.0–6.0)]. If a complete absorption after oral and rectal dosing is assumed, the fraction of the rectal dose entering the liver at first pass can be calculated to be 88% (55–99%). The higher systemic availability and intersubject variability after rectal dosing does not seem to be caused by differences in first-pass liver metabolism but rather by hepatic bypass of a varying portion of administered drug. This portion seems to be typical for an individual and might be explained by anatomical differences between subjects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226330
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Design of a suitable formulation of FK613, a novel antiallergic agent, based on its pharmacokinetic and pharmacodynamic properties in healthy subjects (1996)
    Springer
    European journal of clinical pharmacology 49 (1996), S. 279-284 
    Details
    ISSN: 1432-1041
    Keywords: Antiallergic drug ; FK613 ; pharmacokinetics ; histamine skin-test ; drug formulation ; urinary excretion ; safety
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The pharmacokinetic and pharmacodynamic properties of FK613, a novel indolyl piperidine derivative, were investigated after oral administrations of 5, 10 and 20 mg in hard gelatin capsules to healthy male volunteers. FK613 was rapidly and almost completely absorbed, and 〉89% was recovered in the urine as the unchanged form. The urinary excretion of FK613 was linearly correlated with plasma concentration and its low water solubility was the main concern regarding the safety. In another experiment using a double-blind crossover design, in which 0 (placebo), 5 and 20 mg FK613 were administered to determine the plasma concentration-effect relationship, suppression of the intradermal histamine-induced skin reaction by FK613 was observed. Thus, the maintenance of a plasma concentration of FK613 in the range of 80–250 ng · ml-1 was recommended to ensure the suppression of histamine-induced wheal by 〉50% and not to exceed the solubility in urine. To achieve this, a new hydrogel-type formulation of FK613 was developed, with the aim both of delaying its absorption, so as to suppress the sharp rise in plasma concentration, and of maintaining the effective concentration for a longer period of time. This formulation was administered after meals at the doses of 20, 30, 40, 50 and 60 mg, and at repeated doses of 40 mg twice daily for 6.5 days to evaluate the pharmacokinetics and safety in healthy subjects. The area under the plasma concentration curve increased linearly with dose, whereas maximum plasma concentration (Cmax) tended to peak as dose increased, indicating the desirable properties of this formulation. Although Cmax exceeded 250 ng/ml at doses of 30 mg or more, no urinary crystal formation was observed on careful inspection of urine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226328
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Rectal pharmacokinetics of budesonide (1996)
    Springer
    European journal of clinical pharmacology 49 (1996), S. 293-298 
    Details
    ISSN: 1432-1041
    Keywords: Budesonide ; enema ; pharmacokinetics ; healthy subjects ; hepatic bypass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The pharmacokinetics and systemic availability of budesonide after rectal administration of two single enema doses (2 mg in 100 ml fluid of almost identical composition) were compared in 15 healthy volunteers. In 11 of these subjects, 2 mg oral budesonide in a gelatine capsule was given on a separate occasion. An intravenous administration (0.5 mg) was given as reference. With this design, individual hepatic bypass of the rectally administered budesonide dose could be estimated. The pharmacokinetics of the two enema formulations were similar, although not bioequivalent. Mean systemic availability was 16% (range 4.2–43%) and 15% (3.2–50%) after rectal administration and 6.3% (2.4–10%) after oral administration. The rectal data revealed a small intra- but a substantial inter-subject variability in systemic availability. Cmax was 3.3 nmol·l-1 (0.95–8.2), 3.0 nmol·l-1 (0.64–8.9) and 1.3 nmol·l-1 (0.61–3.0), respectively, for the three formulations. Absorption was rapid and essentially terminated within 3 h after rectal dosing [tmax=1.3 h for both formulations (range 0.5–2.0)], but was slower after oral dosing [tmax=2.1 h (1.0–6.0)]. If a complete absorption after oral and rectal dosing is assumed, the fraction of the rectal dose entering the liver at first pass can be calculated to be 88% (55–99%). The higher systemic availability and intersubject variability after rectal dosing does not seem to be caused by differences in first-pass liver metabolism but rather by hepatic bypass of a varying portion of administered drug. This portion seems to be typical for an individual and might be explained by anatomical differences between subjects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226330
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Increase in magnesium plasma level after orally administered trimagnesium dicitrate (1996)
    Springer
    European journal of clinical pharmacology 49 (1996), S. 317-323 
    Details
    ISSN: 1432-1041
    Keywords: Magnesium ; Plasma level ; pharmacokinetics ; bioavailability ; circadian fluctuation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Magnesium plasma concentrations were measured in healthy probands before and after administration of trimagnesium dicitrate by the oral and intravenous routes. There was a notable circadian fluctuation of the plasma concentration with a peak in the evening hours. After oral administration of 12 and 24 mmol magnesium, a long-lasting, statistically significant increase in plasma magnesium concentration measured as the increase in area under the curve (AUC) between 0 and 12 h, of 3.1% and 4.6%, respectively, was found. After intravenous administration of 4 and 8 mmol magnesium, AUCs increased by 9.5% and 16.1%, respectively. The decline in the plasma magnesium concentration after i.v. administration was compatible with a three-compartment model with a terminal half-time of about 8 h. Although no absolute value of the oral bioavailability of trimagnesium dicitrate could be determined from the data, our results may be important in helping to elucidate the influence of magnesium preparations on the plasma magnesium concentration. By comparing the effects of different preparations, it should be possible to estimate the relative oral bioavailability and the bioequivalence of these preparations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226334
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Multiple-dose clinical pharmacology of the catechol-O-methyl-transferase inhibitor tolcapone in elderly subjects (1996)
    Springer
    European journal of clinical pharmacology 50 (1996), S. 47-55 
    Details
    ISSN: 1432-1041
    Keywords: Key words Tolcapone ; Elderly; levodopa ; pharmacokinetics ; pharmacodynamics ; multiple-dose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract. Objective: The purpose of this study was to assess the multiple-dose clinical pharmacology of tolcapone, a novel catechol-O-methyltransferase (COMT) inhibitor, in elderly subjects. Methods: The drug was administered orally t.i.d. for 7 days to four sequential groups of eight elderly subjects (gender ratio1:1) at doses of 100, 200, 400 and 800 mg in a double-blind, randomised, placebo-controlled, ascending-multiple-dose design. On days 2 and 7, a single dose of levodopa/benserazide 100/25 mg was given 1 h after the first intake of tolcapone. Plasma concentrations of tolcapone, its metabolite 3-O-methyltolcapone, levodopa and 3-O-methyldopa were determined during the course of the study in conjunction with COMT activity in erythrocytes. Results: Tolcapone was well tolerated at all dose levels, with a slight increase in gastrointestinal adverse events in females at higher doses. The drug was rapidly absorbed and eliminated and showed no changes in pharmacokinetics with time during multiple doses of 100 and 200 mg t.i.d. At doses of 400 and 800 mg t.i.d., tolcapone accumulated moderately as reflected in increased Cmax and AUC values. Despite the long half-life of 3-O-methyltolcapone (39 h), only minor accumulation occurred due to suppression of its formation by tolcapone. The pharmacodynamics of tolcapone did not change during the week of treatment as reflected in inhibition of COMT activity in erythrocytes, the derived parameters of the plasma concentration-effect relationship (inhibitory Emax model with constant EC50 values) and the effect on levodopa pharmacokinetics (1.6 to 2.5-fold increase in bioavailability). This suggests the absence of tolerance development and the insignificance of the altered pharmacokinetics at 400 and 800 mg t.i.d. with regard to the pharmacodynamics. Conclusion: The results of this study offer promising perspectives for the application of tolcapone as adjunct therapy to levodopa in the treatment of Parkinson’s disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050068
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    A comparison of the pharmacokinetics and pharmacodynamics of cilazapril between Chinese and Caucasian healthy, normotensive volunteers (1996)
    Springer
    European journal of clinical pharmacology 50 (1996), S. 57-62 
    Details
    ISSN: 1432-1041
    Keywords: Key words Cilazapril ; Caucasians ; Chinese; cilazaprilat ; pharmacokinetics ; pharmacodynamics ; ACE inhibitor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract. Methods: The pharmacokinetics and pharmacodynamics of the angiotensin converting enzyme (ACE) inhibitor cilazapril were studied in 12 Chinese and 13 Caucasian, healthy, normotensive volunteers on their normal diet. Cilazapril was given orally as a single 2.5 mg capsule. Plasma was sampled for assay of the active metabolite, cilazaprilat, plasma renin activity (PRA), aldosterone, angiotensin I (AI) and ACE-activity. Plasma concentrations of the active drug were measured by radioimmunoassay. Blood pressure and heart rate were measured at regular intervals. Results: The pharmacokinetic parameters of cilazaprilat were similar in the two ethnic groups. No significant difference in plasma concentrations was found at any of the time points. However, the weight-adjusted plasma clearance was significantly higher in the Chinese group, which is compatible with their lower body weight. The effects on plasma hormones were also comparable, although there was a somewhat greater rise in PRA and greater fall in aldosterone levels in Chinese than in Caucasians. The effect of cilazapril on blood pressure and heart rate was greater than was previously reported in healthy volunteers. Systolic (SBP) and diastolic (DBP) blood pressure were significantly reduced in both groups, but there was a more prolonged reduction in DBP in Caucasians. In addition, heart rate (HR) was significantly increased from baseline from 5 h onwards in Chinese subjects and significantly higher in comparison with Caucasians at most time points from 1.5 h onwards. The pharmacokinetic parameters of cilazapril were essentially the same in healthy, normotensive Chinese and Caucasians. Cilazapril reduced blood pressure acutely in both groups, with good tolerance. The inhibition of ACE in relationship to time and the plasma concentrations of cilazaprilat were similar in the two groups, although the changes in PRA and aldosterone suggest an ethnic difference in the responses of the renin-angiotensin-aldosterone system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050069
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Pharmacokinetic interaction between cyclosporine and the dihydropyridine calcium antagonist felodipine (1996)
    Springer
    European journal of clinical pharmacology 50 (1996), S. 203-208 
    Details
    ISSN: 1432-1041
    Keywords: Key words Cyclosporine ; Felodipine; dehydrofelodi-pine ; pharmacokinetics ; blood pressure ; drug interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: In a double blind, randomised, placebo-controlled, cross-over study 12 healthy male volunteers were allocated to receive felodipine + placebo, cyclosporine + placebo, and felodipine + cyclosporine in order to investigate the interaction between the calcium channel blocker felodipine and cyclosporine as it affects the pharmacokinetics of felodipine, dehydrofelodipine, and cyclosporine, and 24-hour blood pressure measurements. Methods: Single doses of cyclosporine (capsules, 5 mg/kg body weight) and of felodipine (extended release (ER) tablets 10 mg) were given at a 1–2 week interval. Plasma drug concentrations were followed for 2 days after drug intake. Results: For cyclosporine, Cmax was increased after combined treatment (16%) compared to cyclosporine alone, but felodipine did not influence other kinetic parameters of cyclosporine. For felodipine, combined treatment with cyclosporine and felodipine increased AUC and Cmax (58% and 151%, respectively) and lowered mean residence time (24%) significantly compared to felodipine alone. For the metabolite dehydrofelodipine, too, AUC and Cmax were increased after the combined treatment (43% and 94%, respectively). Mean 24-hour systolic and diastolic blood pressures were significantly lower after felodipine, both when felodipine was given alone (121/68 mmHg) and in combination with cyclosporine (122/68 mmHg) compared to cyclosporine alone (127/73 mmHg). Conclusion: A combined single dose of cyclosporine and felodipine in healthy subjects increased the AUC and Cmax of felodipine suggesting a cyclosporine-induced decrease in the first-pass metabolism of felodipine, whereas the AUC of cyclosporine was only slightly increased by felodipine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050093
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Effect of food on the bioavailability of oxybutynin from a controlled release tablet (1996)
    Springer
    European journal of clinical pharmacology 50 (1996), S. 221-223 
    Details
    ISSN: 1432-1041
    Keywords: Key words Oxybutynin; effect of food ; N-desethyl oxybutynin ; bioavailability ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The effect of food on the bioavailability of oxybutynin was assessed in a randomised cross-over study in 23 healthy volunteers. A single oral 10 mg dose of a controlled release oxybutynin tablet was administered after a high fat breakfast and to fasting subjects. The AUC, Cmax, tmax, t1/2 and MRT of oxybutynin and its active metabolite N-desethyloxybutynin were determined. Results: Breakfast did not change the AUC of oxybutynin but increased the AUC of N-desethyloxybutynin by about 20% . The Cmax of oxybutynin and N-desethyl oxybutynin were two-fold higher when the drug was administered after breakfast compared to the fasting state. Conclusion: Breakfast significantly reduced the MRT of oxybutynin and N-desethyloxybutynin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050096
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Stereoselective pharmacokinetics of mefloquine in young children (1996)
    Springer
    European journal of clinical pharmacology 50 (1996), S. 241-244 
    Details
    ISSN: 1432-1041
    Keywords: Key words Mefloquine ; Children; enantiomer ; pharmacokinetics ; stereoselectivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: the stereospecificity of mefloquine pharmacokinetics in children has been investigated. Patients: Twelve children aged 6 to 24 months were treated for uncomplicated falciparum malaria with a single oral dose of 25 mg⋅kg−1 racemic mefloquine in combination with sulfadoxine and pyrimethamine. Methods: concentrations of mefloquine enantiomers were determined using a coupled achiral-chiral chromatographic system. Pharmacokinetic parameters were calculated using model-independent analysis. Results: Maximum plasma concentrations, areas under the curve and apparent plasma elimination half-lives were higher for the (−) enantiomer than its antipode. In contrast, the apparent volume of distribution (V/f) and total clearance (Cl/f) values were higher for the (+) enantiomer. Conclusion: the stereoselectivity of mefloquine pharmacokinetics is similar to that observed in adults.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050100
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Effect of itraconazole on the pharmacokinetics and pharmacodynamics of zopiclone (1996)
    Springer
    European journal of clinical pharmacology 51 (1996), S. 331-334 
    Details
    ISSN: 1432-1041
    Keywords: Key words Zopiclone ; Itraconazole; drug interaction ; pharmacokinetics ; pharmacodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: We studied the possible interaction between itraconazole, a potent inhibitor of CYP3A, and zopiclone, a short-acting hypnotic. Methods: A double-blind, randomized, two-phase crossover design was used. Ten healthy young subjects received daily either 200 mg itraconazole or placebo for 4 days. On day 4 they ingested a single 7.5-mg oral dose of zopiclone. Plasma concentrations of zopiclone and itraconazole were determined and pharmacodynamic responses were measured up to 17 h. Results: Itraconazole significantly increased the Cmax of zopiclone from 49 to 63 ng ⋅ ml−1. The t1/2 of zopiclone was prolonged from 5.0 to 7.0 h. The AUC(0–∞) of zopiclone was increased from 415 to 719 ng ⋅ ml−1 h by itraconazole. No statistically significant differences were observed in the pharmacodynamic responses between the groups. Conclusion: Itraconazole has a statistically significant pharmacokinetic interaction with zopiclone but this is only of limited clinical importance, at least in young adults.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050207
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Influence of age, frailty and liver function on the pharmacokinetics of brofaromine (1996)
    Springer
    European journal of clinical pharmacology 49 (1996), S. 387-391 
    Details
    ISSN: 1432-1041
    Keywords: Key words Liver function tests; elderly ; pharmacokinetics ; geriatrics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The pharmacokinetics of brofaromine, a selective inhibitor of monoamine oxidase A, was evaluated in 12 frail elderly patients (66–92 y) and 12 healthy volunteers (20–35 y). Methods: Quantitative liver function tests were performed to show whether brofaromine elimination in the elderly could be predicted from noninvasive assessment of CYP1A2 activity (caffeine clearance) or liver plasma flow (sorbitol clearance). Results: In the elderly the AUC of brofaromine was significantly increased (e.g. for the 75 mg dose 43.2 vs 19.9 μmol*h⋅l−1, clearance was reduced (5.0 vs. 11.8 l⋅h−1), the volume of distribution was smaller (130 vs. 230 l), and the half-life was slightly increased (19.0 vs. 14.2 h). No significant correlation was observed between hepatic plasma flow and brofaromine clearance (r = 0.41, P = 0.05), whereas CYP1A2 activity and brofaromine clearance were tightly correlated (r = 0.94, P 〈 0.0001). Conclusion: Caffeine clearance, a simple, noninvasive test of CYP1A2 activity, is predictive of brofaromine clearance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050037
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Influence of age, frailty and liver function on the pharmacokinetics of brofaromine (1996)
    Springer
    European journal of clinical pharmacology 49 (1996), S. 387-391 
    Details
    ISSN: 1432-1041
    Keywords: Liver function tests ; elderly ; pharmacokinetics ; geriatrics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The pharmacokinetics of brofaromine, a selective inhibitor of monoamine oxidase A, was evaluated in 12 frail elderly patients (66–92 y) and 12 healthy volunteers (20–35 y). Methods: Quantitative liver function tests were performed to show whether brofaromine elimination in the elderly could be predicted from noninvasive assessment of CYP1A2 activity (caffeine clearance) or liver plasma flow (sorbitol clearance). Results: In the elderly the AUC of brofaromine was significantly increased (e.g. for the 75 mg dose 43.2 vs 19.9 μmol*h·l−1, clearance was reduced (5.0 vs. 11.8 l·h−1), the volume of distribution was smaller (130 vs. 230 l), and the half-life was slightly increased (19.0 vs. 14.2 h). No significant correlation was observed between hepatic plasma flow and brofaromine clearance (r=0.41, P=0.05), whereas CYP1A2 activity and brofaromine clearance were tightly correlated (r=0.94, P〈0.0001). Conclusion: Caffeine clearance, a simple, noninvasive test of CYP1A2 activity, is predictive of brofaromine clearance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203783
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of moxisylyte in healthy volunteers after intracavernous injection of increasing doses (1996)
    Springer
    European journal of clinical pharmacology 49 (1996), S. 411-415 
    Details
    ISSN: 1432-1041
    Keywords: Moxisylyte ; pharmacokinetics ; intracavernous administration ; healthy volunteers ; adverse events ; metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The concentration-time profiles of specific metabolites of moxisylyte, an α-adrenoceptor blocking agent, in the plasma and urine from 18 healthy volunteers were investigated after intracavernous (IC) administrations at three dose levels (10, 20 and 30 mg). Results: Four metabolites, unconjugated desacetyl-moxisylyte (DAM), DAM glucuronide, and DAM and monodesmethylated DAM (MDAM) sulphates were found in plasma and urine. For all metabolites, t1/2 elimination was independent of the administered dose (1.19 h for unconjugated DAM; 1.51 h for DAM glucuronide; 1.51 h for DAM sulphate; and 2.17 h for MDAM sulphate). Cmax and AUC increased in direct proportion to dose, except for the inactive DAM glucuronide. Any the differences detected were small and equivalence of the three doses can be accepted. Conclusion: The pharmacokinetics of moxisylyte in humans following intracavernous administration were linear in the dose range 10 to 30 mg.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203788
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Therapeutic monitoring of nalbuphine: transplacental transfer and estimated pharmacokinetics in the neonate (1996)
    Springer
    European journal of clinical pharmacology 49 (1996), S. 485-489 
    Details
    ISSN: 1432-1041
    Keywords: Nalbuphine ; Neonate ; therapeutic drug monitoring ; placental transfer ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Nalbuphine, a mixed agonist-antagonist opiate, is commonly used as a systemic analgesic during labour. Recent reports of perinatal adverse effects prompted us to carry out therapeutic nalbuphine monitoring in obstetric analgesia. Because data on fetomaternal transfer are scarce and the pharmacokinetics of this drug in the neonate are largely unknown, we report data obtained from 28 parturients treated with nalbuphine either intramuscularly and/or intravenously during labour. Plasma nalbuphine levels were measured by high-performance liquid chromatography (HPLC) with electrochemical detection. At delivery, 30–150 min after maternal administration, nalbuphine concentrations ranged from 5.0 to 79.2 ng·ml−1 in mother plasma samples and from 3.0 to 46.6 ng·ml−1 in umbilical cord plasma samples. Nalbuphine concentrations were highly correlated to dose. The fetomaternal ratio was high: 0.74 and not correlated to the administered dose of nalbuphine. An estimated plasma half-life of 4.1 h was calculated from two determinations in the neonate based on the assumption of a monoexponential decay of nalbuphine concentrations. Apart from a flattening of the fetal heart rate tracing in 54% of the cases, only one neonate had a low Apgar score at birth. The apparent prolonged half-life of nalbuphine in the neonate indicates the usefulness of an intramuscular injection of naloxone to prevent recurrence of cardiorespiratory depression due to nalbuphine administration to the mother.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195935
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of quinine in patients with chronic renal failure (1996)
    Springer
    European journal of clinical pharmacology 49 (1996), S. 497-501 
    Details
    ISSN: 1432-1041
    Keywords: Quinine ; Malaria ; pharmacokinetics ; chronic renal failure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Methods: We investigated the pharmacokinetics of quinine (Qn) following administration of a single oral dose of 600 mg Qn sulphate in six male Thai patients with a moderate degree of chronic renal failure (CRF), and six male Thai subjects with normal renal function. Results: The drug was well tolerated in both groups of subjects; no major adverse reactions were observed. A marked alteration in the pharmacokinetics of Qn was found in patients with CRF compared to healthy subjects; there were six signifiicant changes in the pharmacokinetic parameters. Absorption was delayed, but increased in CRF (tmax 4.5 vs 1.6 h, Cmax 6.17 vs 3.45 μg·ml−1). Total clearance was significantly reduced 0.94 vs 2.84 ml·min−1·kg−1, whereas Vz/f remained unchanged (1.82 vs 2.78 1·kg−1). This resulted in the increased values of AUC and prolongation of the t1/2z and MRT in the patients (AUC 181.5 vs 61.8 μg·min−1·ml−1, t1/2z 26 vs 9.7 h, MRT 36.4 vs 11.3 h). Median concentrations of plasma unbound fraction of Qn collected at 4 h after drug administration in patients and healthy subjects were 7.3 vs 9.8%, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195937
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Evaluation of plasma and urinary salbutamol levels in COPD (1996)
    Springer
    European journal of clinical pharmacology 51 (1996), S. 91-93 
    Details
    ISSN: 1432-1041
    Keywords: Key words Salbutamol; nebulised ; pharmacokinetics ; COPD ; overnight urinary salbutamol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: To evaluate the use of trough plasma salbutamol and overnight urinary salbutamol excretion in the assessment of nebulised salbutamol delivery in patients with chronic obstructive pulmonary disease (COPD). Methods: Twenty in-patients with COPD receiving nebulised salbutamol, age 69.7 years, FEV1 38.1% predicted, were studied on two consecutive days, receiving four 2.5 mg doses of nebulised salbutamol on day 1 and four 5 mg doses of nebulised salbutamol on day 2, the first dose at 8.00 h the last dose at 22.00 h. Salbutamol delivery was assessed after the last dose by trough plasma salbutamol 8.00 h and overnight urinary excretion of salbutamol (22.00–8.00 h). Results: Levels of urinary salbutamol were detectable in all 20 patients at both doses, whereas for plasma salbutamol detectable levels were only found in 16/20 cases at the 2.5 mg dose and in all cases at the 5 mg dose. For overnight urinary salbutamol (μg⋅10 h−1  n = 20) the results were 141 for 2.5 mg and 249 for 5 mg. The dose ratio for urinary salbutamol between 2.5 mg and 5 mg doses was 1.83. Results for plasma salbutamol (ng/ml, n = 16) were 1.58 at 2.5 mg and 2.43 at 5 mg: dose ratio (geometric mean) 1.49. Conclusion: Overnight urinary salbutamol provides a simple and effective measure of nebulised salbutamol delivery in patients with COPD, which would be suitable for studying nebuliser performance and compliance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050166
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Plasma concentrations and pharmacokinetics of idebenone and its metabolites following single and repeated doses in young patients with mitochondrial encephalomyopathy (1996)
    Springer
    European journal of clinical pharmacology 51 (1996), S. 167-169 
    Details
    ISSN: 1432-1041
    Keywords: Key words Idebenone; mitochondrial encephalomyopathy ; young patients ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The pharmacokinetics and tolerance of idebenone after single or repeated doses have been studied in young patients with mitochondrial encephalomyopathy. Results: No significant adverse effects were noted. In 3 out of 7 patients idebenone induced overall stimulation and improvement in arousal. Plasma concentrations of idebenone and its main metabolites were determined and the pharmacokinetic parameters of idebenone after single and repeated doses were estimated. During the single dose study, the mean plasma concentrations of idebenone and its main metabolites and mean pharmacokinetic parameters were comparable to published results (Cmax = 452.2 ng ⋅ ml−1, tmax = 2.3 h, AUC = 26 μg ⋅ ml−1 ⋅ h, t1/2β = 16.5 h). During the repeated doses study, no significant difference was found between mean residual plasma concentrations of idebenone on Day 2 (47 ng ⋅ ml−1) and Day 5 (70.6 ng ⋅ ml−1), and mean t1/2β of idebenone after the single and after repeated dose studies, i.e., there was no evidence of accumulation. Although idebenone did not appear to accumulate during this study, the coadministration of anticonvulsants, often prescribed during mitochondrial encephalomyopathy, can affect its pharmacokinetics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050179
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Macromolecular Carrier Systems for Targeted Drug Delivery: Pharmacokinetic Considerations on Biodistribution (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 820-831 
    Details
    ISSN: 1573-904X
    Keywords: macromolecular carrier ; pharmacokinetics ; targeting ; protein drugs ; gene medicines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This review article describes the current status and future perspectives of site-specific drug delivery by means of macromolecular carrier systems. Basic aspects and recent advances of targeted delivery of 1) conventional drugs, 2) protein drugs, and 3) gene medicines including antisense oligonucleotides and plasmid DNA, are reviewed from a pharmacokintic perspective. Successful in vivo application of macromolecular carrier systems requires pharmacokinetic considerations at whole body, organ, cellular and subcellular levels. The integration of simultaneous research progress in the multidisciplinary fields such as biochemistry, cell and molecular biology, pharmacology, and pharmacokinetics will accelerate the emergence of marketed drugs with macromolecular carrier systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016084508097
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Targeted Delivery of Doxorubicin via Sterically Stabilized Immunoliposomes: Pharmacokinetics and Biodistribution in Tumor-bearing Mice (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 861-868 
    Details
    ISSN: 1573-904X
    Keywords: sterically stabilized immunoliposomes ; targeting ; doxorubicin ; lung metastases ; pharmacokinetics ; biodistribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To evaluate benefits in tumor localization, availability, and noncancerous organ distribution of doxorubicin (DOX) delivered via small (≤120 nm) sterically stabilized immunoliposomes targeted against a tumor-associated antigen in fibrosarcoma-bearing mice. Methods. DOX-loaded liposomes were prepared with (i) specific monoclonal IgG3 antibody (32/2, D-SSIL-32/2); (ii) non-specific IgG3 (D-SSIL-IgG); or (iii) no IgG (D-SSL) on their surface. Equal DOX amounts were injected intravenously via each type of liposome into BALB/c mice carrying experimental lung metastases of a polyoma virus-induced fibrosarcoma (A9 etc 220) expressing a polyoma virus-induced tumor-associated antigen (PAA) on their surface. Metastases occurred mainly in lung. Mice were treated at 3 stages of tumor development (micrometastases, medium-size metastases, and large, necrotic metastases). Performance evaluation was based on time-dependent quantification of DOX and DOX metabolites (DOX-M) in lung tumor, noncancerous organs, and plasma. Results. (i) DOX delivered via both SSIL retained the prolonged circulation time typical of DOX delivered via D-SSL. (ii) DOX accumulation in noncancerous organs was similar for all preparations. Low levels of DOX-M were obtained for all three preparations in all organs except liver, suggesting a similar processing, (iii) Preparations differed in behavior in lung tumor depending on tumor size and microanatomy. Only at the micrometastases stage were the specifically targeted D-SSIL-32/2 superior to D-SSL and D-SSIL-IgG, delivering 2–4 times more drug into the tumor, (iv) DOX-M level in all three tumor stages was in the following order: D-SSIL-32/2 〉〉 D-SSL 〉〉 D-SSIL-IgG, suggesting that DOX delivered as D-SSIL-32/2 is most available to tumor cells. Conclusions. The advantage of specific targeting of sterically stabilized liposomes is expressed mainly in increasing availability of DOX to tumor cells in a way which is dependent on tumor microanatomy. The impact of this advantage to therapeutic efficacy remains to be determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016096910822
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Bioequivalence assessment of etoposide phosphate and etoposide using pharmacodynamic and traditional pharmacokinetic parameters (1996)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 24 (1996), S. 313-325 
    Details
    ISSN: 1573-8744
    Keywords: etoposide ; etoposide phosphate ; bioequivalence ; pharmacokinetics ; pharmacodynamics ; humans ; cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The bioequivalence of etoposide phosphate, a prodrug of etoposide, to etoposide was assessed in a randomized, crossover study in 29 patients with histologically established solid tumors that had failed conventional treatment. Cohorts of patients received one treatment course each of etoposide and etoposide phosphate which consisted of a 100 mg/m2 per day etoposide equivalent dose infused iv over 1 hr on a Day 1 to 5 schedule of treatment. The second course was administered 21 days later or on recovery of blood cell counts. Plasma and urine samples were collected over 24 hr on Day 1 of each course and assayed for etoposide content by a validated HPLC/UV method. Resulting data were subjected to noncompartmental pharmacokinetic analysis. Hematology profiles were obtained by collecting blood samples prior to the first course and twice a week after each course. The pharmacodynamics and pharmacokinetics of etoposide were virtually identical after the two treatments. The point estimates (90% confidence intervals) for nadir WBC, granulocytes, hemoglobin, and platelets expressed as % decrease from the baseline, and for the pharmacokinetic parameters, Cmax, and AUC0-∞, after intravenous etoposide phosphate relative to etoposide were 100% (96%, 105%), 97% (91%, 103%), 95% (82%, 109%), 95% (84%, 106%), 107% (101%, 113%), and 113% (107%, 119%), respectively. Therefore, etoposide phosphate is bioequivalent to etoposide based on pharmacokinetic and pharmacodynamic assessments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02353515
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Interspecies Pharmacokinetics of a Novel Hematoregulatory Peptide (SK&F 107647) in Rats, Dogs, and Oncologic Patients (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 794-797 
    Details
    ISSN: 1573-904X
    Keywords: allometric scaling ; peptide ; pharmacokinetics ; hematology ; infection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To study the pharmacokinetics of SK&F 107647, a novel hematoregulatory agent, in rats, dogs, and patients with non-lymphoid solid tumor malignancy. Methods. Sprague Dawley rats and beagle dogs (n = 6 each; 3 M, 3 F) were given 25 mg/kg of SK&F 107467 as an iv bolus injection, and patients (n = 6; 4 M, 2 F) received 100 ng/kg as a 2 hour iv infusion. Plasma samples were assayed for drug using either HPLC (rat and dog) or RIA (human). Results. In each species the plasma clearance (CL) of SK&F 107647 was low in relation to hepatic blood flow, and the volume of distribution (Vdss) was reflective of distribution to extracellular body water. The plasma CL in humans was near that of average glomerular filtration rate. Using allometric equations for interspecies scaling (Y = a·Wb), body-weight normalized human pharmacokinetic data were reasonably predicted using either the body weight normalized rat or the dog data. The allometric exponents (b) for CL, Vdss, and T1/2 of SK&F 107647 were 0.63, 0.94, and 0.29, respectively. Conclusions. Use of a limited pool of available animal data allowed for reasonable predictions of human pharmacokinetics of SK&F 107647.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016020221300
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Evaluation of Pharmacokinetic Studies: Is It Useful to Take into Account Concentrations Below the Limit of Quantification? (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 839-845 
    Details
    ISSN: 1573-904X
    Keywords: pharmacokinetics ; precision ; accuracy ; limit of quantification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. Based on real data, to evaluate the usefulness of taking into account samples with values below the limit of quantification (LOQ) for the evaluation of pharmacokinetic studies. Methods. To compare for two drugs, after single dose administration the pharmacokinetic parameters obtained by using a poorly sensitive assay (PSA) and a highly sensitive assay (HSA), acting as reference; To evaluate the results of pharmacokinetic studies in the light of different values for the LOQ. Results. Under certain conditions, such as homogeneous population, sufficient subject number, sufficient sampling times and acceptable accuracy (CV 〈 20%) for the concentrations, it is possible to get valuable and more reliable kinetic information by using concentrations obtained with a poor precision (CV 〉 20%). This is especially true for the parameters associated with the terminal phase, such as t1/2β and AUC, but also for parameters depending to a lesser extent on the terminal phase, such as tl/2α and AUCtn. Moreover, the mean concentration time curve is by far best defined by using all the concentrations. Conclusions. In some situations, it is preferable to use concentrations with values below the LOQ to evaluate the results of pharmacokinetic studies. However, this should not be the rule, especially when this does not bring any additional information, or when it is possible to increase the sensitivity of the bioanalytical assay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016088609005
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Effects on the Pharmacokinetics and Pharmacodynamics in the Elderly of Coadministering Ramipril with Water, Apple Juice, and Applesauce (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 639-642 
    Details
    ISSN: 1573-904X
    Keywords: ramipril ; ACE inhibitor ; capsules ; pharmacokinetics ; pharmacodynamics ; elderly patients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016022827235
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    A Pharmacokinetic Approach for Evaluating Cytokine Binding Macromolecules as Antagonists (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 84-90 
    Details
    ISSN: 1573-904X
    Keywords: antibodies ; soluble receptors ; immunoadhesins, cytokines ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. Cytokine binding macromolecules such as antibodies and soluble receptors sometimes produce undesirable agonist-like activities instead of the expected antagonist-like effects when the cytokine binding macromolecule extends the half-life of a short-lived cytokine. The purpose of this paper is to identify the pharmacokinetic and physicochemical properties that can cause these agonist-like activities. Methods. A simple pharmacokinetic model was used to determine whether a given cytokine binding macromolecule will function effectively as an antagonist in therapeutic situations in which cytokine is released chronically. Results. The model proposed satisfactorily fits experimental data for soluble interleukin-4 receptor and for an anti-interleukin-4 monoclonal antibody under conditions in which agonist-like and antagonist activity are observed. Conclusions. We show that the unexpected agonist-like activities result only when there is nonlinearity in the cytokine-cytokine receptor interaction and the cytokine binding macromolecule prolongs the half-life of the cytokine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016033418207
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Hemodynamic effects of intravenous elgodipine in coronary artery disease during rest and exercise, and basic pharmacokinetic parameters (1996)
    Springer
    Cardiovascular drugs and therapy 10 (1996), S. 573-580 
    Details
    ISSN: 1573-7241
    Keywords: elgodipine ; calcium channel antagonist ; coronary artery disease ; haemodynamics ; exercise ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using an echo-Doppler method (Quantascope), the hemodynamic profile of the calcium channel antagonist elgodipine (64 μg/kg, iv) was investigated in 22 patients with angina pectoris at rest and during exercise. A placebo control was used. At rest, elgodipine significantly decreased systemic vascular resistance as well as systolic and diastolic blood pressure, while increasing cardiac output and stroke volume. During supine bicycle exercise at constant workload, elgodipine significantly increased cardiac output and stroke volume, and decreased the rate-pressure-product (double product); the exercise systolic blood pressure was decreased without change in the diastolic component. Elgodipine significantly reduced the incidence and severity (self-rated pain score) of exercise-induced anginal symptoms. Heart rate was not affected by elgodipine, either at rest or during exercise. In particular, no negative inotropy could be inferred from the echo-Doppler data. In the elgodipine plasma concentration profile (HPLC), three phases of elimination with half-life times of less than 1 hour, between 3 and 7 hours, and between 10 and 24 hours may be distinguished, indicating a “shallow” and a “deep” compartment. The hemodynamic data indicate an intermediate pharmacodynamic profile of elgodipine, lying between that of other dihydropyridines and that of compounds such as verapamil or diltiazem.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00050999
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Preclinical testing of an anti-erbB-2 recombinant toxin (1996)
    Springer
    Breast cancer research and treatment 38 (1996), S. 19-25 
    Details
    ISSN: 1573-7217
    Keywords: recombinant immunotoxins ; erbB-2 ; pharmacokinetics ; toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The performance of OLX-209 indicates it should enter phase I clinical testing. OLX-209 is a recombinant toxin targeting theerbB-2 oncoprotein. The design of OLX-209 takes advantage of improvements in immunotoxin technology to produce a molecule that is smaller and more potent than a conventional chemically linked antibody-toxin conjugate. The targeting portion of OLX-209 is a single chain antibody structure derived from the anti-erbB-2 hybridoma, e23. This antibody has unusual specificity in that it does not bind to most normal tissue including peripheral nerve or kidney tissue. Preclinical testing showsin vitro activity against breast cancer cell lines in the pM range. Efficacy testing in five models of human cancer indicates that a dose of 43 µg/kg causes reproducible tumor regressions. Efficacy can be achieved on a variety of schedules of administration. The effective dose results in no measurable change in serum liver enzymes when delivered to mice or primates. The LD10 is over twice the effective dose in mice. The pharmacokinetics indicate a t1/2 of 50 minutes for both mice and cynomolgus monkeys. Serum concentrations of more than ten times those observed at the effective dose can be achieved in monkeys with no evidence of toxicity. Antigenicity of OLX-209 is surprisingly low. These results form the basis for the clinical testing phase for OLX-209.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01803780
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Development and Pharmacokinetics of Galactosylated Poly-L-Glutamic Acid as a Biodegradable Carrier for Liver-Specific Drug Delivery (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 880-884 
    Details
    ISSN: 1573-904X
    Keywords: drug carrier ; hepatic targeting ; poly-L-glutamic acid ; galactosylation ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. A biodegradable carrier for the liver-specific delivery of drugs was developed using poly-L-glutamic acid (PLGA) modified with galactose (galactosylated PLGA or Gal-PLGA), and its feasibility was investigated in mice. Methods. 111In-PLGA and 111In-Gal-PLGAs were injected in mice and their distribution and biodegradation properties were studied. Results. After intravenous injection, 111In-PLGA was rapidly eliminated from the plasma and recovered mainly in the kidneys and urine. Approximately 15% of the dose was recovered in the liver, predominantly in the nonparenchymal cells. 111In-Gal-PLGAs were taken up by the liver parenchymal cells. Derivatives having 16 or more galactose residues were taken up by the liver to a higher extent (〉60% of the dose). The hepatic clearance of 111n-Gal-PLGAs correlated with their number of galactose residues. 111In-Gal18-PLGA was degraded into low-molecular weight products in the liver. Conclusions. The advantageous in vivo properties of Gal-PLGA as a liver-specific biodegradable carrier of drugs were demonstrated in mice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016053128569
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Bioavailability and efficacy of omeprazole given orally and by nasogastric tube (1996)
    Springer
    Digestive diseases and sciences 41 (1996), S. 475-479 
    Details
    ISSN: 1573-2568
    Keywords: omeprazole ; gastric acid secretion ; nasogastric tube ; pharmacokinetics ; pentagastrin ; cytochrome P-450 ; bioavailability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We compared the bioavailability and the efficacy of omeprazole provided either as encapsulated enteric-coated granules or as enteric-coated granules delivered via a nasogastric tube in 10 healthy subjects. Omeprazole reduced mean pentagastrin-stimulated peak gastric acid secretion by 85.5%±23.7% when delivered orally and by 79.6%±32.1% when delivered by nasogastric tube; the mean plasma omeprazole concentration area under the curve (AUC) was 2.02±0.79 after oral delivery and 1.74±1.89 after nasogastric tube delivery. There was no significant difference in these parameters between the two routes of administration, and there was excellent intrasubject correlation between oral and nasogastric percent acid suppression and AUC. There was a close correlation between AUC and percent acid suppression at AUC values below 0.6, and complete acid suppression at AUC values above 0.6, regardless of the delivery route. We conclude that omeprazole delivered as enteric-coated granules via nasogastric tube provides equal bioavailability and gastric acid suppression as omeprazole given orally in its proprietary formulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02282321
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Comparison of the pharmacokinetics and effects on the hemostatic system of saruplase and urokinase in patients with acute myocardial infarction (1996)
    Springer
    Journal of thrombosis and thrombolysis 3 (1996), S. 385-390 
    Details
    ISSN: 1573-742X
    Keywords: saruplase ; urokinase ; pharmacokinetics ; hemostasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of the study was to compare in a single trial, using identical methodology, the pharmacokinetic properties and the effect on the hemostatic system of saruplase (unglycosylated scu-PA) and urokinase (glycosylated tcu-PA). Twenty-four patients with an acute myocardial infarction were either treated with saruplase (n = 12; 20 mg IV bolus followed by a 60 mg infusion for 60 minutes) or urokinase (n = 12; 1.5 million IU IV bolus followed by 1.5 million IU infusion for 60 minutes). Blood samples from saruplase-treated patients were analyzed for u-PA antigen and total u-PA and tcu-PA activities; those from urokinase-treated patients for u-PA antigen and tcu-PA activity. The effect of treatment on, including recovery of, plasma α2-antiplasmin, fibrinogen, and plasminogen was examined in both groups. The total clearance of urokinase (179 ± 55 ml/ min) is about half that of saruplase (406 ± 154 ml/min), and the mean residence time of urokinase (59.1 ± 22.5 minutes) is nearly twice that of saruplase (28.3 ± 7.8 minutes), which results in a slower elimination of urokinase from plasma. Whether differences in the pharmacokinetic behavior of the unglycosylated saruplase and the glycosylated urokinase observed in this study are due to the difference in glycosylation or to other factors is not resolved. The systemic effect of saruplase on α2,-antiplasmin, fibrinogen, and plasminogen is similar to that of urokinase, although retarded.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00133082
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Predicted and actual BCNU concentrations in normal rabbit brain during intraarterial and intravenous infusions (1996)
    Springer
    Journal of neuro-oncology 30 (1996), S. 7-18 
    Details
    ISSN: 1573-7373
    Keywords: BCNU ; brain cancer ; intraarterial ; pharmacokinetics ; rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Normal New Zealand White rabbits were used to compare theoretical brain concentrations (based upon pharmacokinetic modeling) with actual experimental concentrations of BCNU following intraarterial (IA) or intravenous (IV) infusions. IA infusion therapy for brain tumor patients has been promising based upon theoretical predictions but of limited effectiveness clinically. Experimentally-measured rabbit carotid artery flow rates (63.9 ± 3.4 ml/min) [mean ± 1 sem] and BCNU systemic clearances (197 ± 10.2 ml/min) predicted a theoretical IA advantage of 4.1 ± 0.2. lpsilateral brain concentrations of BCNU during and after IA infusions (20 mg/min/m2 over 15 minutes) were: 16.2 ± 2.9, 19.0 ± 3.9, 20.3 ± 2.8, 4.8 ± 2.5, 2.1 ± 1.5, and 1.7 ± 1.6 μg/gm brain at 5, 10, 15, 25, 35, and 45 minutes after infusion start. Mean concentrations at same time points in contralateral hemisphere (IA infusions) were: 7.1 ± 1.8, 9.0 ± 1.8, 10.3 ± 0.7, 4.2 ± 1.4, 2.2 ± 1.2, 2.0 ± 1.5 μg/gm brain. Concentrations in either hemisphere during IV infusions were similar to contralateral hemisphere during IA infusions. Comparison of ipsilateral: contralateral hemisphere ratios during and after IA infusions were: 3.2 ± 0.4, 2.6 ± 0.3, 2.2 ± 0.3, 1.1 ± 0.3, 1.0 ± 0.4, and 0.9 ± 0.3 at the same time points. Although these data show higher drug concentrations with IA infusions, actual values were considerably less than predicted by theoretical modeling. This discrepancy between theoretical and experimental results emphasizes need for further study of causes and remedies so that IA therapy can achieve better drug concentrations with less toxicity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00177438
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    The disposition kinetics and residues of fenvalerate in tissues following a single dermal application to black bengal goats (1996)
    Springer
    Veterinary research communications 20 (1996), S. 265-272 
    Details
    ISSN: 1573-7446
    Keywords: fenvalerate ; goat ; pharmacokinetics ; residue ; skin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The disposition kinetics of fenvalerate were studied in goats after dermal application of 100 ml of 0.25% (w/v) solution. The insecticide persisted in the blood for 72 h. The mean (±SEM) V d(area) and apparent t 1/2 (β) were 9.92±1.44 L/kg and 17.51±2.65 h, while the AUC and ClB values were respectively 82.15±7.40 μg h/ml and 0.56±0.05 L/(kg h). Four days after the dermal application, the highest concentration of fenvalerate residues was found in the adrenal gland, followed by the biceps muscle, omental fat, liver, kidney, lung and cerebrum in that order. Fenvalerate caused hyperglycaemia but had no effect on serum protein and cholesterol levels. Serum acetylcholinesterase activities were increased after 24 h but were below the initial values from 48 to 120 h.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00366924
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    The efficacy and pharmacokinetics of long-term low-level intraruminal administration of tricalbendazole in buffalo with induced fasciolosis (1996)
    Springer
    Veterinary research communications 20 (1996), S. 461-468 
    Details
    ISSN: 1573-7446
    Keywords: anthelmintic ; buffalo ; dosage ; efficacy ; fasciolosis ; metabolites ; pharmacokinetics ; triclabendazole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A study was conducted on the pharmacokinetics and therapeutic efficacy of triclabendazole at three low dose rates of 0.5, 1.0 and 1.5 mg/kg body weight in buffaloes experimentally infected with Fasciola gigantica. The pharmacokinetics were compared with the effects of a single intraruminal dose at 24.0 mg/kg body weight in uninfected buffaloes. At all three dose rates, an equilibrium between the absorption of triclabendazole and the disposition of its metabolites was observed by days 3 and 4 and remained almost unchanged thereafter. Continuous daily dosing at 1.5 mg/kg body weight proved to be efficacious against liver fluke infection in buffaloes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00419183
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Preliminary pharmacokinetic and pharmacodynamic studies on flunixin meglumine in donkeys (1996)
    Springer
    Veterinary research communications 20 (1996), S. 469-472 
    Details
    ISSN: 1573-7446
    Keywords: donkey, flunixin ; pharmacokinetics ; prostaglandin ; thromboxane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00419184
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    The effect of induced fever on the biokinetics of norfloxacin and its interaction with probenecid in goats (1996)
    Springer
    Veterinary research communications 20 (1996), S. 473-479 
    Details
    ISSN: 1573-7446
    Keywords: fever ; fluoroquinolone ; goat ; norfloxacin ; pharmacokinetics ; probenecid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The kinetic profiles of norfloxacin were evaluated in afebrile, febrile and probenecid pre-treated (70 mg/kg orally) febrile goats after a single intravenous (i.v) dose (5 mg/kg). Fever was induced and maintained for 12 h by injecting Escherichia coli endotoxin (0.2 μg/kg, i.v.) and repeating it in half the dose (0.1 μg/kg) 5 h later. The plasma pharmacokinetic values for norfloxacin were best represented using a two-compartment open model. The peak norfloxacin plasma level of 90.52±3.18 μg/ml attained in the probenecid pre-treated febrile goats was higher than that in the febrile (75.46±0.72 μg/ml) or afebrile goats (62.25±1.23 μg/ml). ClB and K el values were significantly (p〈0.01) decreased in febrile compared with afebrile goats. These values were further reduced in febrile goats after probenecid pre-treatment. However, t 1/2β was not affected by the fever-probenecid interaction. Norfloxacin may be used as an infusion with probenecid in caprine diseases where very high plasma levels are required to combat resistant organisms such as Bacteroides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00419185
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Stereoselective disposition of flurbiprofen from a mutual prodrug with a histamine H2-antagonist to reduce gastrointestinal lesions in the rat (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 494-502 
    Details
    ISSN: 0899-0042
    Keywords: hydrolysis ; carboxylesterase ; bioconversion ; plasma concentration ; pharmacokinetics ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The in vitro and in vivo stereoselective hydrolysis characteristics of the mutual prodrug FP-PPA, which is a conjugate of flurbiprofen (FP) with the histamine H2-antagonist PPA, to reduce gastrointestinal lesions induced by FP were investigated and compared with those of FP methyl ester (rac-FP-Me) and FP ethyleneglycol ester (rac-FP-EG). The rac-FP derivatives were hydrolyzed preferentially to the (+)-S-isomer in plasma and to the (-)-R-isomer in liver and small intestinal mucosa. Interestingly, in the gastric mucosa, the stereoselectivity of hydrolysis of (-)-R-FP-PPA was opposite from that of rac-FP-Me and rac-FP-EG, which suggested that the stereoselective hydrolysis of FP-PPA was helpful in reducing gastric damage induced by (+)-S-FP. However, hydrolysis of all rac-FP derivatives was found to be catalyzed by carboxylesterases in the gastric mucosa. The stereoselective disposition of FP enantiomers early after intravenous administration of rac-FP-PPA could be explained by the stereoselective formation of (-)-R-FP from rac-FP-PPA in the liver. (-)-R-FP-PPA was completely hydrolyzed to form (-)-R-FP in vivo, while 78% of (+)-S-FP-PPA was hydrolyzed to (+)-S-FP, with a corresponding decrease in the area under the curve. Twenty-five percent of (+)-S-FP-PPA might be eliminated as the intact prodrug or its metabolites other than FP. The most important bioconversion of FP-PPA occurred in plasma, and additional hydrolysis of the R-enantiomer in liver resulted in the stereoselectivity observed following both i.v. and p.o. administration. © 1996 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 51
    Electronic Resource
    Electronic Resource
    Preconditioning Mixed Finite Element Saddle-point Elliptic Problems (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 1-20 
    Details
    ISSN: 1070-5325
    Keywords: preconditioning saddle-point problems ; eigenvalue estimation ; mixed finite element method ; minimum residual method ; second-order elliptic problems ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: We consider saddle-point problems that typically arise from the mixed finite element discretization of second-order elliptic problems. By proper equivalent algebraic operations the considered saddle-point problem is transformed to another saddle-point problem. The resulting problem can then be efficiently preconditioned by a block-diagonal matrix or by a factored block-matrix (the blocks correspond to the velocity and pressure, respectively). Both preconditioners have a block on the main diagonal that corresponds to the bilinear form(δ is a positive parameter) and a second block that is equal to a constant times the identity operator. We derive uniform bounds for the negative and positive eigenvalues of the preconditioned operator. Then any known preconditioner for the above bilinear form can be applied. We also show some numerical experiments that illustrate the convergence properties of the proposed technique.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 52
    Electronic Resource
    Electronic Resource
    Masthead (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996) 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030101
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Multifrontal QR Factorization in a Multiprocessor Environment (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 275-300 
    Details
    ISSN: 1070-5325
    Keywords: sparse QR factorization ; multifrontal method ; parallelism ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: We describe the design and implementation of a parallel QR decomposition algorithm for a large sparse matrix A. The algorithm is based on the multifrontal approach and makes use of Householder transformations. The tasks are distributed among processors according to an assembly tree which is built from the symbolic factorization of the matrix ATA.We first address uniprocessor issues and then discuss the multiprocessor implementation of the method. We consider the parallelization of both the factorization phase and the solve phase. We use relaxation of the sparsity structure of both the original matrix and the frontal matrices to improve the performance. We show that, in this case, the use of Level 3 BLAS can lead to very significant gains in performance. We use the eight processor Alliant˜FX/80 at CERFACS to illustrate our discussion.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 54
    Electronic Resource
    Electronic Resource
    Two-stage Multisplitting Methods with Overlapping Blocks (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 113-124 
    Details
    ISSN: 1070-5325
    Keywords: iterative methods ; linear systems ; multisplittings ; overlap ; parallel algorithms ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: Parallel two-stage multisplitting methods with overlap for the solution of linear systems of algebraic equations are studied. It is shown that, under certain hypotheses, the method with overlap is asymptotically faster than that without overlap. Experiments illustrating this phenomenon are presented.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 55
    Electronic Resource
    Electronic Resource
    On Fast Computations with the Inverse to Harmonic Potential Operators via Domain Decomposition (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 91-111 
    Details
    ISSN: 1070-5325
    Keywords: boundary integral operators ; domain decomposition ; interface operators ; fast elliptic problem solvers ; parallel algorithms ; preconditioning ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: In this paper a method for fast computations with the inverse to weakly singular, hypersingular and double layer potential boundary integral operators associated with the Laplacian on Lipschitz domains is proposed and analyzed. It is based on the representation formulae suggested for above-mentioned boundary operations in terms of the Poincare-Steklov interface mappings generated by the special decompositions of the interior and exterior domains. Computations with the discrete counterparts of these formulae can be efficiently performed by iterative substructuring algorithms provided some asymptotically optimal techniques for treatment of interface operators on subdomain boundaries. For both two- and three-dimensional cases the computation cost and memory needs are of the order O(N logp N) and O(N log2 N), respectively, with 1 ≤ p ≤ 3, where N is the number of degrees of freedom on the boundary under consideration (some kinds of polygons and polyhedra). The proposed algorithms are well suited for serial and parallel computations.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 56
    Electronic Resource
    Electronic Resource
    Short Communication: Two Properties of Diagonally Dominant Matrices (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 173-177 
    Details
    ISSN: 1070-5325
    Keywords: diagonally dominant matrix ; determinant ; norm ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: A property of strictly diagonally dominant matrices and a generalization of a Varga's bound for ∥ A-1∥∞ to the case ∥ A-1B∥∞ are given and the two-sided bounds for the determinants of strictly diagonally dominant matrices are derived
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 57
    Electronic Resource
    Electronic Resource
    Piecewise Polynomial Solutions Without a priori Break Points (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 513-524 
    Details
    ISSN: 1070-5325
    Keywords: regularization ; I-norm ; discontinuous solutions ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: In certain inverse problems it is useful to be able to compute solutions which are, in some sense, as simple as possible. For example,k one may wish to compute solutions which are piecewise constant and with as few discontinuities as possible. Such solutions are suited to describe models, e.g., geological layers, where the coarse structure is more important than the fine structure. A natural generalization of piecewise constant functions is piecewise polynomial solutions. In this paper we present a new algorithm which is capable of computing solutions that are piecewise polynomials, without having to specify a priori the positions of the break points between the polynomial pieces.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 58
    Electronic Resource
    Electronic Resource
    On IOM(q): The Incomplete Orthogonalization Method for Large Unsymmetric Linear Systems (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 491-512 
    Details
    ISSN: 1070-5325
    Keywords: unsymmetric ; Krylov subspace ; IOM(q) ; FOM ; truncated ; basis vector ; orthonormality ; convergence ; restarted ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: The incomplete orthogonalization method (IOM(q)), a truncated version of the full orthogonalization method (FOM) proposed by Saad, has been used for solving large unsymmetric linear systems. However, no convergence analysis has been given. In this paper, IOM(q) is analysed in detail from a theoretical point of view. A number of important results are derived showing how the departure of the matrix A from symmetric affects the basis vectors generated by IOM(q), and some relationships between the residuals for IOM(q) and FOM are established. The results show that IOM(q) behaves much like FOM once the basis vectors generated by it are well conditioned. However, it is proved that IOM(q) may generate an ill-conditioned basis for a general unsymmetric matrix such that IOM(q) may fail to converge or at least cannot behave like FOM. Owing to the mathematical equivalence between IOM(q) and the truncated ORTHORES(q) developed by Young and Jea, insights are given into the convergence of the latter. A possible strategy is proposed for choosing the parameter q involved in IOM(q). Numerical experiments are reported to show convergence behaviour of IOM(q) and of its restarted version.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 59
    Electronic Resource
    Electronic Resource
    Block Two-stage Methods for Singular Systems and Markov Chains (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 413-426 
    Details
    ISSN: 1070-5325
    Keywords: iterative methods ; linear systems ; singular matrices ; block methods ; multisplitting ; two-stage ; non-stationary ; Markov chains ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: The use of block two-stage methods for the iterative solution of consistent singular linear systems is studied. In these methods, suitable for parallel computations, different blocks, i.e., smaller linear systems, can be solved concurrently by different processors. Each of these smaller systems are solved by an (inner) iterative method. Hypotheses are provided for the convergence of non-stationary methods, i.e., when the number of inner iterations may vary from block to block and from one outer iteration to another. It is shown that the iteration matrix corresponding to one step of the block method is convergent, i.e., that its powers converge to a limit matrix. A theorem on the convergence of the infinite product of matrices with the same eigenspace corresponding to the eigenvalue 1 is proved, and later used as a tool in the convergence analysis of the block method. The methods studied can be used to solve any consistent singular system, including discretizations of certain differential equations. They can also be used to find stationary probability distribution of Markov chains. This last application is considered in detail.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 60
    Electronic Resource
    Electronic Resource
    Editorial (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 349-350 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: No Abstract
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 61
    Electronic Resource
    Electronic Resource
    Multilevel Preconditioners for Mixed Methods for Second Order Elliptic Problems (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 427-453 
    Details
    ISSN: 1070-5325
    Keywords: mixed method ; nonconforming method ; multilevel preconditioner ; condition number ; second order elliptic problem ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: A new approach for constructing algebraic multilevel preconditioners for mixed finite element methods for second order elliptic problems with tensor coefficients on general geometry is proposed. The linear system arising from the mixed methods is first algebraically condensed to a symmetric, positive definite system for Lagrange multipliers, which corresponds to a linear system generated by standard nonconforming finite element methods. Algebraic multilevel preconditioners for this system are then constructed based on a triangulation of the domain into tetrahedral substructures. Explicit estimates of condition numbers and simple computational schemes are established for the constructed preconditioners. Finally, numerical results for the mixed finite element methods are presented to illustrate the present theory.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 62
    Electronic Resource
    Electronic Resource
    Conference diary (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 455-457 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030502
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    A Comparison of Three Basic Conjugate Direction Methods (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 473-489 
    Details
    ISSN: 1070-5325
    Keywords: conjugate gradients ; biconjugate gradients ; conjugate directions ; non-symmetric linear systems ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: In this paper three basic conjugate direction methods for solving non-symmetric linear systems are described and compared. All three have entirely different basic structures and, consequently, completely different characteristics. The motivation for this work is the comparative assessment of the methods in order to decide which of the three is the most suitable for further development.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 64
    Electronic Resource
    Electronic Resource
    Masthead (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996) 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030601
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Conference diary (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 543-545 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030602
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Toeplitz Preconditioners with Block Structure for First-order PDEs (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 21-44 
    Details
    ISSN: 1070-5325
    Keywords: first-order PDEs ; iterative methods ; preconditioners ; Toeplitz ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: Preconditioners to nonsymmetric, nondiagonally dominant systems of equations are constructed and examined numerically. The preconditioners are based on a Toeplitz approach with a certain symmetry that we define. The inversion of the preconditioners is defined through a Fast Modified Sine Transform. As a model problem we study the systems of equations arising from a implicit time-discretization with a large time-step of a scalar hyperbolic PDE.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 67
    Electronic Resource
    Electronic Resource
    Generalization of Strang's Preconditioner with Applications to Toeplitz Least Squares Problems (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 45-64 
    Details
    ISSN: 1070-5325
    Keywords: Toeplitz least squares problems ; circulant preconditioned conjugate gradient method ; deconvolution ; image restoration ; atmospheric imaging ; medical imaging ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: In this paper, we propose a method to generalize Strang's circulant preconditioner for arbitrary n-by-n matrices An. The th column of our circulant preconditioner Sn is equal to the th column of the given matrix An. Thus if An is a square Toeplitz matrix, then Sn is just the Strang circulant preconditioner. When Sn is not Hermitian, our circulant preconditioner can be defined as . This construction is similar to the forward-backward projection method used in constructing preconditioners for tomographic inversion problems in medical imaging. We show that if the matrix An has decaying coefficients away from the main diagonal, then is a good preconditioner for An. Comparisons of our preconditioner with other circulant-based preconditioners are carried out for some 1-D Toeplitz least squares problems: min ∥ b - Ax∥2. Preliminary numerical results show that our preconditioner performs quite well, in comparison to other circulant preconditioners. Promising test results are also reported for a 2-D deconvolution problem arising in ground-based atmospheric imaging.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 68
    Electronic Resource
    Electronic Resource
    A Parallel Preconditioned Iterative Realization of the Panel Method in 3D (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 65-80 
    Details
    ISSN: 1070-5325
    Keywords: boundary value problem ; boundary element method ; preconditioning ; iterative method ; fast Fourier transform ; parallel algorithm ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: The parallel version of precondition iterative techniques is developed for matrices arising from the panel boundary element method for three-dimensional simple connected domains with Dirichlet boundary conditions. Results were obtained on an nCube-2 parallel computer showing that preconditioned iterative methods are very well suited also in three-dimensional cases for implementation on an MIMD computer and that they are much more efficient than usual direct solution techniques.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 69
    Electronic Resource
    Electronic Resource
    Conference diary (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 91-93 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030102
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Masthead (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996) 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030401
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Conference diary (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 345-348 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030402
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    The Finite Difference Based Fast Adaptive Composite Grid Method (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 391-411 
    Details
    ISSN: 1070-5325
    Keywords: finite difference discretization ; fast adaptive composite grid method ; convergence rate ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: The fast adaptive composite grid (FAC) method is an iterative method for solving discrete boundary value problems on composite grids. McCormick introduced the method in [8] and considered the convergence behaviour for discrete problems resulting from finite volume element discretization on composite grids. In this paper we consider discrete problems resulting from finite difference discretization on composite grids. We distinguish between two obvious discretization approaches at the grid points on the interfaces between fine and coarse subgrids. The FAC method for solving such discrete problems is described. In the FAC method several intergrid transfer operators appear. We study how the convergence behaviour depends on these intergrid transfer operators. Based on theoretical insights, (quasi-)optimal intergrid transfer operators are derived. Numerical results illustrate the fast convergence of the FAC method using these intergrid transfer operators.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 73
    Electronic Resource
    Electronic Resource
    Masthead (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996) 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030501
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Dykstra's Algorithm for a Constrained Least-squares Matrix Problem (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 459-471 
    Details
    ISSN: 1070-5325
    Keywords: alternating projection method ; Dykstra's algorithm ; patterned matrix ; constrained least-squares ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: We apply Dykstra's alternating projection algorithm to the constrained least-squares matrix problem that arises naturally in statistics and mathematical economics. In particular, we are concerned with the problem of finding the closest symmetric positive definite bounded and patterned matrix, in the Frobenius norm, to a given matrix. In this work, we state the problem as the minimization of a convex function over the intersection of a finite collection of closed and convex sets in the vector space of square matrices.We present iterative schemes that exploit the geometry of the problem, and for which we establish convergence to the unique solution. Finally, we present preliminary numberical results to illustrate the performance of the proposed iterative methods.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 75
    Electronic Resource
    Electronic Resource
    Analysis of Algorithms for Orthogonalizing Products of Unitary Matrices (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 125-145 
    Details
    ISSN: 1070-5325
    Keywords: orthogonalization ; QR factorization ; polar decomposition ; subspace tracking ; error analysis ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: We consider the problem of computing Uk = QkUk-1(where U0 is given) in finite precision (εM = machine precision) where U0 and theQi are known to be unitary. The problem is that Ûk, the computed product may not be unitary, so one applies an O(n2) orthogonalizing step after each multiplication to(a) prevent Ûk from drifing too far from the set of untary matrices(b) prevent Ûk from drifting too far from Uk the true product.Our main results are1. Scaling the rows to have unit length after each multiplication (the cheaptest of the algorithms considered) is usually as good as any other method with respect to either of the criteria (a) or (b).2. A new orthogonalization algorithm that guarantees the distance of Ûk (k = 1, 2, …) to the set of unitary matrices is bounded by n3.5εM for any choice of Qi.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 76
    Electronic Resource
    Electronic Resource
    Masthead (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996) 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030201
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Estimate of the Constant in Two Strengthened C.B.S. Inequalities for F.E.M. Systems of 2D Elasticity: Application to Multilevel Methods and a Posteriori Error Estimators (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 147-159 
    Details
    ISSN: 1070-5325
    Keywords: elasticity ; finite-element ; multilevel ; a posteriori error estimation ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: The constant γ in the strengthened Cauchy-Buniakowski-Schwarz (C.B.S.) inequality plays a crucial role in the convergence rate of multilevel iterative methods as well as in the efficiency of a posteriori error estimators, that is in the framework of finite element approximations of SPD problems.We consider the approximation of the 2D elasticity problem by the Courant element. Concerning multilevel convergence rate, that is the γ corresponding to nested general triangular meshes of size h and 2h, we have proved that γ2≤ 3/4$ uniformly on the mesh and the Poisson ratio. Concerning error estimator, that is the γ corresponding to quadratic and linear approximations on the same mesh, numerical computations have shown that the exact γ for a reference element deteriorates that is goes to one, when the Poisson ratio tends to 1/2
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 78
    Electronic Resource
    Electronic Resource
    On the Smoothing Property of Multigrid Methods in the Non-symmetric Case (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 161-172 
    Details
    ISSN: 1070-5325
    Keywords: smoothing property ; multigrid method ; semi-iterative smoother ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: In this paper we present an extension of Reusken's Lemma about the smoothing property of a multigrid method for solving non-symmetric linear systems of equations. One of the consequences of this extended lemma is the verification of the smoothing property for all damping factors οε(0, 1). Additionally, a semi-iterative smoother is constructed which gives, in some sense, optimal smoothing rate estimates.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 79
    Electronic Resource
    Electronic Resource
    Conference diary (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 179-183 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030202
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Parallel Algorithms for Orthotropic Problems (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 185-203 
    Details
    ISSN: 1070-5325
    Keywords: orthotropic partial differential equation ; preconditioned conjugate gradient method ; parallel algorithm ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: Finite element meshes and node-numberings suitable for parallel solution with equally loaded processors are presented for linear orthotropic elliptic partial differential equations. These problems are of great importance, for instance in the oil and airfoil industries. The linear systems of equations are solved by the conjugate gradient method preconditioned by modified incomplete factorization, MIC. The basic method presented, is based on fronts of uncoupled nodes and unlike earlier methods it has the advantage of no requirement of a specific orientation of the mesh. This method is however, in general, restricted to small degree of anisotropy in the differential equation. Another method, which does not suffer from this limitation, uses rotation of the differential equation and spectral equivalence. The rotation is made in such a way that in the new co-ordinate system, the basic method is applicable. The spectral equivalence property is used for estimation of the condition number of the preconditioned system. Both methods are suitable for implementation on parallel computers. The computer architecture could be single instruction multiple data (SIMD) as well as multiple instruction multiple data (MIMD) with shared or distributed memory. Implementation of the basic method on a shared memory parallel computer shows a significant improvement by use of the MIC method compared with the diagonal scaling preconditioning method.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 81
    Electronic Resource
    Electronic Resource
    Overlapping Domain Decomposition Algorithms for General Sparse Matrices (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 221-237 
    Details
    ISSN: 1070-5325
    Keywords: sparse matrix ; iterative methods ; preconditioning ; graph partitioning ; domain decomposition ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: Domain decomposition methods for finite element problems using a partition based on the underlying finite element mesh have been extensively studied. In this paper, we discuss algebraic extensions of the class of overlapping domain decomposition algorithms for general sparse matrices. The subproblems are created with an overlapping partition of the graph corresponding to the sparsity structure of the matrix. These algebraic domain decomposition methods are especially useful for unstructured mesh problems. We also discuss some difficulties encountered in the algebraic extension, particularly the issues related to the coarse solver.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 82
    Electronic Resource
    Electronic Resource
    Convergence Estimates of Multilevel Additive and Multiplicative Algorithms for Non-symmetric and Indefinite Problems (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 205-220 
    Details
    ISSN: 1070-5325
    Keywords: elliptic equations ; multilevel methods ; finite element ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: New uniform estimates for multigrid algorithms are established for certain non-symmetric indefinite problems. In particular, we are concerned with the simple additive algorithm and multigrid (V(1,0)-cycle) algorithms given in [5]. We prove, without full elliptic regularity assumption, that these algorithms have uniform reduction per iteration, independent of the finest mesh size and number of refinement levels, provided that the coarsest mesh size is sufficiently small.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 83
    Electronic Resource
    Electronic Resource
    Masthead (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996) 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030301
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Globalization of Newton's Method for Solving Non-linear Equations (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 239-249 
    Details
    ISSN: 1070-5325
    Keywords: non-linear equations ; global convergence ; Lagrangians ; non-linear programming ; Lagrangian globalization ; detour potentials ; homotopy methods ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: The Lagrangian globalization (LG) method for non-linear equation-solving proposed in [10] is developed through theoretical analysis, the formulation of a particular LG algorithm, and a numerical illustration. New merit functions (termed detour potentials) for non-linear equation-solving, which broaden the LG concept, are also defined.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 85
    Electronic Resource
    Electronic Resource
    Conference diary (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 251-254 
    Details
    ISSN: 1070-5325
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nla.1680030302
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Two-level Preconditioner with Small Coarse Grid Appropriate for Unstructured Meshes (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 255-274 
    Details
    ISSN: 1070-5325
    Keywords: conjugate gradient method ; preconditioning ; two-level method ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: The presented paper contains a suggestion and an analysis of a two-level preconditioner appropriate for unstructured meshes. The convergence analysis is done for H1-equivalent forms in the two-dimensional case; ways for generalization are discussed, too. The efficiency is demonstrated by numerical experiments.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 87
    Electronic Resource
    Electronic Resource
    DQGMRES: a Direct Quasi-minimal Residual Algorithm Based on Incomplete Orthogonalization (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 329-343 
    Details
    ISSN: 1070-5325
    Keywords: iterative methods ; GMRES ; Krylov methods ; incomplete orthogonalization ; quasi-minimization ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: We describe a Krylov subspace technique, based on incomplete orthogonalization of the Krylov vectors, which can be considered as a truncated version of GMRES. Unlike GMRES(m), the restarted version of GMRES, the new method does not require restarting. Like GMRES, it does not break down. Numerical experiments show that DQGMRES(k) often performs as well as the restarted GMRES using a subspace of dimension m=2k. In addition, the algorithm is flexible to variable preconditioning, i.e., it can accommodate variations in the preconditioner at every step. In particular, this feature allows the use of any iterative solver as a right-preconditioner for DQGMRES(k). This inner-outer iterative combination often results in a robust approach for solving indefinite non-Hermitian linear systems.
    Additional Material: 9 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 88
    Electronic Resource
    Electronic Resource
    A Regularization Procedure for Σn-i=1fi(zj)xi = g(zj), ( j = 1, 2, …, n) (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 81-90 
    Details
    ISSN: 1070-5325
    Keywords: linear systems ; regularization ; divided differences ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: A regularization procedure for linear systems of the type fi(zj)xi = g(zj), (j = 1, 2, …, n) is presented, which is particularly useful in the case when z1, z2, …, zn are close to each other. The associated numerical algorithm was tested on several examples for which analytic solutions do exist and was found to yield highly accurate results.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 89
    Electronic Resource
    Electronic Resource
    Low-rank Orthogonal Decompositions for Information Retrieval Applications (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 301-327 
    Details
    ISSN: 1070-5325
    Keywords: information ; latent semantic indexing ; low-rank ; orthogonal ; matrices ; metrieval ; singular value decomposition ; sparse ; ULV and URV decompositions ; updating ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: Current methods to index and retrieve documents from databases usually depend on a lexical match between query terms and keywords extracted from documents in a database. These methods can produce incomplete or irrelevant results due to the use of synonyms and polysemus words. The association of terms with documents (or implicit semantic structure) can be derived using large sparse {\it term-by-document} matrices. In fact, both terms and documents can be matched with user queries using representations in k-space (where 100 ≤ k ≤ 200) derived from k of the largest approximate singular vectors of these term-by-document matrices. This completely automated approach called latent semantic indexing or LSI, uses subspaces spanned by the approximate singular vectors to encode important associative relationships between terms and documents in k-space. Using LSI, two or more documents may be closeto each other in k-space (and hence meaning) yet share no common terms. The focus of this work is to demonstrate the computational advantages of exploiting low-rank orthogonal decompositions such as the ULV (or URV) as opposed to the truncated singular value decomposition (SVD) for the construction of initial and updated rank-k subspaces arising from LSI applications.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 90
    Electronic Resource
    Electronic Resource
    A Multigrid Method Based on Incomplete Gaussian Elimination (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 369-390 
    Details
    ISSN: 1070-5325
    Keywords: multigrid ; incomplete Gaussian elimination ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: In this paper we introduce and analyse a new Schur complement approximation based on incomplete Gaussian elimination. The approximate Schur complement is used to develop a multigrid method. This multigrid method has an algorithmic structure that is very similar to the algorithmic structure of classical multigrid methods. The resulting method is almost purely algebraic and has interesting properties with respect to variation in problem parameters.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 91
    Electronic Resource
    Electronic Resource
    Multilevel Minimal Residual Methods for Nonsymmetric Elliptic Problems (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Linear Algebra with Applications 3 (1996), S. 351-367 
    Details
    ISSN: 1070-5325
    Keywords: multilevel preconditioning ; Krylov subspace methods ; GMRES, nonsymmetric elliptic problems ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: The subject of this paper is to study the performance of multilevel preconditioning for nonsymmetric elliptic boundary value problems. In particular, a minimal residual method with respect to an appropriately scaled norm, measuring the size of the residual projections on all levels, is studied. This norm, induced by the multilevel splitting, is also the basis for a proper stopping criterion. Our analysis shows that the convergence rate of this minimal residual method using the multilevel preconditioner by Bramble, pasciak and Xu is bounded independently of the mesh-size. However, the convergence rate deteriorates with increasing size of the skew-symmetric part. Our numerical results show that by incorporating this into a multilevel cycle starting on the coarsest level, one can save fine-level-iterations and, therefore, computational work.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 92
    Electronic Resource
    Electronic Resource
    Parallel computation of radiation view factors between two arbitrarily oriented surfaces (1996)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 12 (1996), S. 43-50 
    Details
    ISSN: 1069-8299
    Keywords: view factor ; radiation ; parallel computation ; heat transfer ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Two implementations for parallel computation of radiation heat transfer view factors are formulated and tested for a model problem. Using a sufficiently large number of processors and a suitable communications paradigm, the solution time for the problem considered here scales linearly with the number of surface elements in the parallel implementation rather than the quadratic scaling obtained using a serial approach. For larger problems, significantly shorter solution times are obtained using the massively parallel Connection Machine 5 than those obtained on a single processor of the Cray C-90, a traditional vector supercomputer. Parallel performance was degraded for implementations using too few processors or data layouts leading to inefficient processor communication.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 93
    Electronic Resource
    Electronic Resource
    A Taylor expansion algorithm for integration of 3D near-hypersingular integrals (1996)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 12 (1996), S. 51-62 
    Details
    ISSN: 1069-8299
    Keywords: boundary element method ; hypersingular integrals ; singular integration ; elasticity ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An algorithm based on the Taylor series expansion is extended to deal with the problem of near-hypersingular integrals occurring in a 3D electrostatic BEM formulation. The integral is evaluated by subtracting out the leading terms in the near-hypersingular part of the integrand and adding it back. The accuracy of the proposed method is demonstrated for a curved element. It is shown that accurate values can be obtained with low orders of Gaussian quadrature.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 94
    Electronic Resource
    Electronic Resource
    Masthead (1996)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 12 (1996) 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640120201
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Conference diary (1996)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 12 (1996), S. 147-148 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640120202
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Annoucement (1996)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 12 (1996), S. 149-150 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640120203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    An asymptotic formula for correcting finite element predicted natural frequencies of membrane vibration problems (1996)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 12 (1996), S. 63-73 
    Details
    ISSN: 1069-8299
    Keywords: asymptotic solution ; natural frequencies ; membrane vibrations ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In the paper an asymptotic formula has been developed to correct the discretization error for the finite element predicted natural frequencies of membrane transverse vibration problems. The general idea behind deriving this asymptotic formula is that, when the finite element size approaches zero, a discretized finite element system approaches a continuous system and the predicted natural frequencies of the system from the finite element analysis therefore approach the exact solutions of the system. Without losing generality, several different finite element mesh patterns have been considered and the same asymptotic formula for correcting the finite element predicted natural frequency has been obtained for all the different mesh patterns because of the uniqueness of the exact solution to the natural frequency of a real structure. The usefulness, effectiveness and efficiency of the present asymptotic formula have been assessed by a simple but critical problem, for which the exact solution is available for comparison. In order to investigate the applicability of the asymptotic formula to practical engineering problems, two challenging membrane vibration problems of irregular shapes, an L-shape and a tapered shape with a circular hole in the centre, have also been analysed. The related numerical results have demonstrated that the asymptotic formula provides a very useful post-processing error corrector for the finite element predicted natural frequencies of membrane transverse vibration problems, even though the problem domains are of irregular shape. The greatest advantage in using the present asymptotic formula is that it yields a solution of higher accuracy, by simply using the formula to correct the rough solution obtained from a much coarser finite element mesh with fewer degrees of freedom, without any further finite element calculation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 98
    Electronic Resource
    Electronic Resource
    Eigenvalue extraction for large finite element models using a new conjugate gradient algorithm (1996)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 12 (1996), S. 77-83 
    Details
    ISSN: 1069-8299
    Keywords: eigenvalue extraction ; conjugate gradient method ; finite element method ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A new conjugate gradient algorithm is presented for extracting eigenvalues from large systems of equations encountered in finite element analysis. The new algorithm involves applying the conjugate gradient method (CGM) to a static problem to generate an equivalent tridiagonal matrix used for eigenvalue computation. The eigenvalues of the tridiagonal matrix are then extracted using a QR factorization. The similarity of the new CGM with the Lanczos method is discussed regarding the need for matrix inversion and reorthogonalization. Several examples using the new method are presented to illustrate its performance.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 99
    Electronic Resource
    Electronic Resource
    A direct method to derive the boundary conditions of the homogenization equation for symmetric cells (1996)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 12 (1996), S. 185-196 
    Details
    ISSN: 1069-8299
    Keywords: homogenization ; boundary conditions ; periodicity ; finite element ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The numerical solution of homogenization equations by the finite element (FE) method is explained briefly. The issue of extracting boundary conditions from the periodicity assumption is addressed and a direct method utilizing symmetry is presented. Using this method, the computation of the elements of the constitutive matrix of a composite material is reduced to a very conventional boundary value problem with known forces and boundary conditions which can be carried out with any FE code. Two examples are presented.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 100
    Electronic Resource
    Electronic Resource
    Masthead (1996)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 12 (1996) 
    Details
    ISSN: 1069-8299
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cnm.1640120401
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...