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  • 1975-1979  (699)
  • 1975  (699)
  • Analytical Chemistry and Spectroscopy  (516)
  • Atomic, Molecular and Optical Physics  (99)
  • Engineering General  (84)
Material
Years
  • 1975-1979  (699)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975) 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. vii 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975) 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 65-77 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectra of twenty acetates and methylates of spirostanol and related furostanol glycosides of high molecular weight (above 650) have been investigated, and the most probable fragmentation patterns of the glycoside derivatives are presented. High resolution mass spectrometry provides useful information concerning the structures of both aglycone and sugar moieties as well as the molecular size of the oligoglycosides.
    Additional Material: 21 Ill.
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  • 5
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of thin-layer chromatography has demonstrated that incubations of indoleamines with 5-methyl[14C]tetrahydrofolic acid and an enzyme previously described as an N-methyltransferase, do not yield Nω, N1 or O-methylated products. Further elucidation by thin-layer chromatography, gas chromatography, mass spectrometry and selected ion monitoring enabled us to identify the reaction products as tetrahydroisoquinolines and tetrahydro-β-carbolines in mixtures incubated respectively with catecholamines and indoleamines in the presence of 5-methyl[14C]tetrahydrofolic acid and enzyme. The alkaloids have been shown to originate from a spontaneous condensation of the corresponding amines with formaldehyde, this latter being formed in the first stage of the reaction by enzymatic conversion from 5-methyltetrahydrofolic acid.
    Additional Material: 5 Ill.
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  • 6
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N6-(2-succinyl)adenosine 5′-phosphate and N-(5-amino-1-ribosyl-4-imidazole carbonyl)-L-aspartic acid ′-phosphate were prepared enzymatically using adenylosuccinate lyase (EC 4.3.2.2) isolated from human erythrocytes. N6-(2-succinyl)adenosine 5′-phosphate, N-(5-amino-1-ribosyl-4-imidazole carbonyl)-L-aspartic acid 5′-phosphate and N-(5-amino-1-ribosyl-4-imidazole carboxamide) 5′-phosphate and the nucleoside and free base analogs of these nucleotides were converted to the trimethylsilyl derivatives and characterized by mass spectrometry. The extent of the trimethylsilylation was greater for adenine substituted compounds compared with those related to aminoimidazole carboxamide. Major mass spectral fragment ions correspond to the intact base plus portions of the sugar skeleton and to electron impact-induced decomposition products of the sugar moiety. Succinyl substitution at N6 of the adenine derivatives leads to characteristic loss of CO2 SiMe3 from the molecular ion. A combination of liquid chromatographic procedures and gas chromatography mass spectrometry gave rapid and unequivocal identification of succinyladenine from human urine.
    Additional Material: 7 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 112-114 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have used peak matching to accurately determine the molecular masses of field desorbed ions. A major advantage over high resolution photoplate recording is that it reduces analysis time without reducing accuracy or sensitivity. Molecular ions of nonvolatile and thermally labile compounds can be mass measured by this technique.
    Additional Material: 3 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975) 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 117-120 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Five children deficient in growth hormone were treated with oxandrolone and human growth hormone. Average nitrogen retained was calculated from nine day balance data. During some balance periods, nitrogen retention was calculated by determination of 15N labeled glycine, as reported in this article. Twenty milligrams of 15N in excess of the natural abundance was administered orally. Urines were collected prior to, as well as after, administration of glycine-15 N and were analyzed for 15N by mass spectrometry. The percentage of 15N ranged up to 0.449% for collection over a 24 hour period, compared with 0.364% from control samples without excess 15N. These 15N data, like those from nitrogen balance, show the stimulating effects of oxandrolone and human growth hormone in the group as a whole.
    Additional Material: 3 Tab.
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 126-130 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the micro-identification of both mono- and diesters of 12-deoxyphorbol based upon a combination of thin-layer chromatography and mass spectrometry. The technique may be used on as little as 5 ml of fresh plant latex. Nine thin-layer systems are described, six of which are adsorption systems based on silica gel or alumina as adsorbent, and three are partition systems using diethyleneglycol as stationary phase. The migration by means of thin-layer chromatography is dependent upon the chain length of the C-13 esterifying acid and on the presence or absence of a free primary hydroxyl group at C-20. By means of mass spectrometry it was possible to confirm the identity of the esterifying moiety at both the C-13 and C-20 positions of 12-deoxy-4βOH-phorbol.
    Additional Material: 4 Tab.
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  • 11
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 133-136 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The urinary excretion by rats of predominantly 2-ethyl-3-deuterohydracrylic acid is a consequence of the intraperitoneal injection of 2-trideuteromethylbutyric acid. A significant fraction of the loading acid also is excreted unchanged. These results support the proposal of an alternate minor pathway of isoleucine catabolism and suggest that the corresponding catabolites in the minor and major pathways, 2-ethylhydracrylic and 2-methyl-3-hydroxybutyric acids, respectively, have significantly different subsequent metabolism.
    Additional Material: 2 Ill.
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  • 12
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. xi 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 121-125 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Field desorption mass spectra of a tripeptide Pro-Leu-Gly-NH2, a pentapeptide Cbz-Gly-Pro-Leu-Gly-Pro and a nonapeptide Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg are presented. In each case, a [M]+· or [M + 1]+ peak of the peptide is obtained. Sufficient fragmentation of the peptide backbone occurred to allow sequence determination of all three peptides. The pentapeptide produced [M]+·, [M + 1]+ and [M + 2]+· ions which also included molecules of ethylacetate, ethanol and/or water bound to the ion.
    Additional Material: 3 Ill.
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  • 14
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 131-132 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for continous mass range specific gas chromatographic detection using the β-slit of a reverse geometry double focusing mass spectrometer. The method has several advantages over total ion current detection, including elimination of the solvent peak from the detector trace and reduction of back ground noise due to column bleeding. The technique has been applied here to detect prostaglandins in biological samples.
    Additional Material: 1 Ill.
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  • 15
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 169-175 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photodecomposition products of aldrin, dieldrin and endrin were investigated by means of gas chromatography mass spectrometry, nuclear magnetic resonance and infrared spectrophotometry. An alternate isomeric product of aldrin and four endrin analogs were encountered. The mass spectra of eight photoproducts are presented with direct inlet spectra of endrin aldehyde and endrin alcohol.
    Additional Material: 13 Ill.
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  • 16
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 190-196 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectroscopic behaviour of prostaglandin A1 and its methyl ester has been studied. Mechanisms are suggested for the majority of fragmentation processes occurring in the spectra of these compounds. The proposed mechanisms have been confirmed by low electron voltage spectra, measurements on metastable ion decompositions, high resolution mass measurements and deuterium labelling.
    Additional Material: 3 Ill.
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  • 17
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A mass fragmentographic method is described for the simultaneous assay of both the acidic and alcoholic metabolites of tyramine, octopamine, dopamine and norepinephrine. The method was successfully applied for the measurement of nanogram quantities of these metabolites in human ventricular and lumbar cerebrospinal fluids and in the rat brain. Mass fragmentography was carried out on the methyl ester/pentafluoroproprionyl derivatives of the acidic and the pentafluoropropionyl derivatives of the alcoholic metabolites, employing an 8 ft 3% SE-54 column. Chemical methods for the synthesis of a number of deuterated isomers (isotopomers) of the above metabolites are also described. These isotopomers were utilized as internal reference standards for the assay of the metabolites in biological materials. They were also used to study the fragmentation reactions of these metabolite derivatives.
    Additional Material: 8 Ill.
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  • 18
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 204-205 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A N-dealkylated metabolite, 1-phenylcyclohexylamine, was detected in a urine sample of a patient who had ingested phencyclidine. The identification was facilitated by a feeding experiment using a mouse administered a 1:1 mixture of unlabeled and phenyl-d5-labeled drug. A control experiment was also performed in which a mouse was fed only the unlabeled drug. Two hydroxylated metabolities were also identified in human urine samples. One of the hydroxylated metabolites has a hydroxy group located at the piperidine moiety of phencyclidine while the other has the hydroxy group located at the cyclohexane ring of the drug. It was also shown that 1-phenyl-cyclohexene detected in the human samples, was an artifact which arose from pyrolysis of phencyclidine during gas chromatography.
    Additional Material: 1 Ill.
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  • 19
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 225-225 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 20
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Interfering nonpolar lipid material was removed from the acetone extracts of several samples of benign hyperplastic prostate tissue. Endogenous steroids were separated by preparative thin-layer chromatography into fractions containing testosterone, 5α-dihydrotestosterone and the 5α-androstane-3, 17-diols, and concentrations of these steroids were measured by molecular ion monitoring of suitable derivatives at a resolution of 8500 to 10 000 during combined gas chromatography mass spectrometry. The sensitivity and specificity of this procedure allowed unequivocal detection of the steroids of interest at the femtomole level and the incorporation of epimers as internal standards enabled accurate quantitative measurements. The results indicated that 5α-dihydrotestosterone is usually the most predominant of the steroids measured, and that of the 5α-androstanediols, only the 3α, 17β and 3β, 17β isomers occur in measurable concentration, with the former usually predominant.
    Additional Material: 6 Ill.
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  • 21
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 176-182 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ultraviolet irradiation of the methanoindene compounds chlordene, 1-hydroxychlordene cis- and trans-chlordane, trans-nonachlor and heptachlor using acetone as the sensitizing solvent yielded caged photoisomers. Electron impact spectra of twelve photoproducts are reported. Structural assignments based on nuclear magnetic resonance, infrared and gas chromatography data are reported for the major photoproducts.
    Additional Material: 14 Ill.
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  • 22
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 23
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 254-260 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The extent of C-methylation, an artifact of the permethylation procedure used to derivatize peptides for mass spectrometric sequencing, was investigated by mass spectrometry. Ten glycine-containing peptides were N-acetylated and then permethylated by the Hakomori method and analyzed by chemical ionization and, in some cases, by electron ionization mass spectrometry. A comparative study was made of the tripeptides Gly Pro Ala and Ala Pro Gly, derivatized by three permethylation procedures. The results show that while C-methylation occurs primarily at glycine, other amino acids (Gln, Glu, Met, Tyr) are also C-methylated, but to a lesser degree. The extent to which C-methylation occurs varies widely and depends on residue position and on the identity of neighboring residues. Such artifacts could lead to serious errors in peptide sequences determined by mass spectrometry, especially when mixtures of peptides are analyzed.
    Additional Material: 4 Tab.
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  • 24
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Incubation of four common cannabinoids with vegetative cultures of the fungus Syncephalastrum racemosum yielded a number of polar metabolites. Major metabolites of Δ9-tetrahydrocannabinol, Δ8-tetrahydrocannabinol, cannabidiol and cannabinol were eluted from preparative thin-layer chromatographic plates and analyzed by gas-liquid chromatography mass spectrometry. The mass spectrum of each of the compounds examined showed a molecular ion corresponding to a monohydroxylated derivative of the parent cannabinoid. Identification of the major metabolite of each cannabinoid as the product of hydroxylation in the penultimate (4′) position of the n-pentyl sidechain was made by analysis of the mass spectra of underivatized and TMS derivatized metabolites and by comparison with model compounds. A number of prominent fragment ions in the mass spectra were identified as arising through known fragmentation pathways of cannabinoids.
    Additional Material: 4 Ill.
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  • 25
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 279-280 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A pressure measuring probe has been built for the chemical ionization source of a Du Pont 21 490-B mass spectrometer. The probe fits exactly in the place of the solid sample probe and, when connected to a Baratron manometer, enables pressure measurement directly in the source. This can be used to calibrate an ionization gauge connected to the source housing or a manometer in the reagent gas inlet line. The probe has been used to determine the maximum source pressure attainable for various reagent gases in the Du Pont 21 490-B mass spectrometer.
    Additional Material: 1 Ill.
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  • 26
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 284-284 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 27
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. viii 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 28
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. x 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 29
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method employing gas-liquid chromatography and combined gas-liquid chromatography mass spectrometry was developed for the quantitative determination of α-D-mannopyranoside-(1 → 3)-β-D-mannopyranoside-(1 → 4)-2-acetamido-2-deoxy-D-glucose in urines. The concentration of this trisaccharide varied between 123 and 469 mg per litre of urine in the patients with mannosidosis but was not detected in twenty normals and two heterozygotes.
    Additional Material: 3 Ill.
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  • 30
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 304-306 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The identification of 6-methoxy 8-aminoquinoline as a metabolite of Primaquine, an important antimalarial drug, is described. The metabolite is present in urine, plasma and erythrocytes following drug ingestion. It was identified by mass fragmentography of its 1H and 2H acetate and the acetate produced from authentic material. No evidence of further metabolites was obtained.
    Additional Material: 3 Ill.
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  • 31
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The field desorption mass spectra of eight rifamycins were obtained and compared with their electron impact mass spectra. All the compounds gave abundant molecular or quasimolecular ions, while no significant fragmentation was observed in the low mass region of the spectra. Therefore, field desorption mass spectrometry has been shown to be of great importance for the determination of the molecular weight of these antibiotics.
    Additional Material: 9 Ill.
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  • 32
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complex mixtures of O-trimethylsilylated polyamino alcohols, which have been generated by either acid or enzymatic hydrolysis of polypeptides and subsequent derivatization, are completely characterized by a gas chromatograph mass spectrometer computer system. These peptide derivatives possess excellent gas chromatographic properties; a wide range of derivatives from di- to hexapeptides may be separated in a single chromatographic experiment. The identification of these compounds, either manually or with the assistance of the computer, is based on three sets of data which are automatically generated after the g.c.m.s. computer experiment: (1) mass spectra, which exhibit sequence-determining ions of high abundance; (2) selected ion records, which allow efficient location of peptide derivatives in the gas chromatogram as well as resolution of incompletely separated fractions; (3) retention indices, which can be calculated from values which have been assigned to each amino acid residue.
    Additional Material: 7 Ill.
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  • 33
    Electronic Resource
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 1-1 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 34
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A routine analysis for micro samples of plasma amino acids by a gas chromatography mass spectrometry computer system has been developed. Isotope ratio determination was used as the quantitating technique via multiple internal standards. The speed of the analysis is increased by omitting the ion exchange purification step and its flexibility is maximized by using repetitive scanning rather than selective ion monitoring. This procedure yields excellent precision and accuracy, as demonstrated by the analysis of a known amino acid mixture and of neonatal plasma.
    Additional Material: 2 Ill.
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  • 35
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 23-30 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An ion doublet chemical ionization mass spectrometry technique was utilized for the rapid detection and elucidation of the structure of a new hydroxylated metabolite of the oral anticoagulant warfarin. This technique involves the use of a 50:50 mixture of stable isotope labeled and unlabeled drug. With this procedure ions found in the mass spectrum which are associated with the administered drug can be identified unambiguously. The unknown metabolite from rat liver microsomal preparations was identified as benzylic hydroxywarfarin by reincubating the microsomes with warfarin specifically labeled in the benzylic position and observing the subsequent loss of label in the product. The ion doublet technique was also employed in a single human study, and benzylic hydroxywarfarin was detected and identified.
    Additional Material: 5 Ill.
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  • 36
    Electronic Resource
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 2 (1975), S. 36-45 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectra of permethyl ethers of twenty-five highly purified oligosaccharides, containing first, aldohexose units only and second, at least one fructose unit, have been determined. It is concluded that spectra of these derivatives can yield considerable structural information, especially in relation to the detection of fructose units, the pyranose/furanose ratio and the position of the glycosidic linkage, and are to be preferred from this point of view to the mass spectra of trimethylsilyl ethers.
    Additional Material: 8 Tab.
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  • 37
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metabolism studies in the rat, dog and cat have demonstrated a definite species difference in biotransformation and elimination of α-1-trans-4-dimethylaminotetrahydro-3-furylcyclohexanephenylglycolate (Lilly 82537), an experimental anticholinergic agent. Separation and identification of urinary and biliary metabolites by gas chromatographic mass spectrometric analysis has shown three mechanisms to be involved in the metabolism of Lilly 82537 in these species; N-demethylation, aliphatic hydroxylation and ester hydrolysis. A major portion of the drug administered was eliminated unaltered in the cat and dog, while only trace quantities of parent drug were observed in the urine and bile of rats. These metabolic differences may be responsible for observed species differences in the pharmacologic activity of Lilly 82537.
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  • 38
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A rapid, sensitive method of analysis for methylphenidate and ritalinic acid in blood and urine has been developed using gas chromatography mass spectrometry and selected ion monitoring for separation and detection. The methylphenidate is isolated by solvent extraction into chloroform and the ritalinic acid is isolated by salting out into isopropyl alcohol, followed by methylation and subsequent solvent extraction. The method has been applied to the study of methylphenidate metabolism and excretion in adults and hyperactive children under-going treatment with methylphenidate.
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  • 39
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    Biological Mass Spectrometry 2 (1975), S. 82-89 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Identification of hydrazine monoamine oxidase inhibitor drugs such as isoniazid, iproniazid, nialamide, isocarboxazid and iproclozide is made by electron impact mass spectrometry using the direct insertion technique. The molecular ion itself, although of low relative abundance, is found in the mass spectra of all compounds studied. Relative intensities of the major fragments and data on metastable ions useful in the identification of these compounds are reported. With the aid of synthesized structurally related products, deuterium labelling of exchangeable hydrazidic and hydrazinic protons and by the use of hexadeuterated isopropylic analogues, detailed information about fragmentation patterns is obtained. Splitting processes are chiefly governed by the nature of the aromatic substituent at the hydrazidic end and the alkyl sidechain located at the second hydrazinic nitrogen. The major fragmentations occurring are loss of small neutral molecules, double rearrangement, cleavage of the N—N bond, amide bond rupture, β-cleavage to the hydrazinic nitrogen atom and McLafferty rearrangements.
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  • 40
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    Biological Mass Spectrometry 2 (1975), S. 31-35 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The advantages and limitations which quadrupole mass filters afford to the field desorption technique with respect to use for routine work are discussed and experimentally confirmed by the analyses of some drugs using a field desorption quadrupole mass spectrometer. The possibility of fast identification of drug intoxication is demonstrated by the analysis of the chloroform extract of urine in a case of overdose of hypnotics.
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  • 41
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    Biological Mass Spectrometry 2 (1975), S. 59-62 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 42
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    Biological Mass Spectrometry 2 (1975), S. 63-64 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 43
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    Biological Mass Spectrometry 2 (1975), S. 64-64 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 44
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thin-layer chromatography and mass spectrometry were used to isolate and identify cyclophosphamide metabolites present in blood of mice. Blood was removed 5, 15, 30 and 45 minutes after intraperitoneal administration and extracted with chloroform followed by methanol. Thin-layer chromatography of the two extracts and the residual solid with or without prior methylation, collection of resulting alkylating components, determination of radioactivity and mass spectral analysis, served to identify cyclophosphamide, 4-ketocyclophosphamide, alcophosphamide, N-dechloroethylcyclophosphamide, carboxyphosphamide, phosphoramide mustard and nor-HN2. The absence of detectable levels of 4-hydroxycyclophosphamide or aldophosphamide in the blood of cyclophosphamide-treated mice suggests that cyclophosphamide is converted rapidly in the liver to carboxyphosphamide, 4-ketocyclophosphamide, phosphoramide mustard and nor-HN2. Direct administration of synthetic 4-hydroxycyclophosphamide to mice and extraction of blood with chloroform demonstrated the recovery of this metabolite in vivo. Analysis of extracts of blood from mice treated with phosphoramide mustard indicated the presence of nor-HN2, 3-(2-chloroethyl)-1,3-oxazolidin-2-one and unchanged drug. Consideration of blood levels, cytotoxicity and alkylating activity of metabolites identified in, or inferred from, this study, implicates phosphoramide mustard as a leading candidate for the biologically active form of cyclophosphamide.
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  • 45
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    Biological Mass Spectrometry 2 (1975), S. 78-81 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Single and multiple ion monitoring is employed to evaluate whether deuteriomethylated allobarbitone or methylated quinalbarbitone is the better internal standard for quantifying methylated allobarbitone through a g.c.m.s. system based on a quadrupole mass spectrometer. It is shown that the coefficient of variation of the single ion monitoring method is substantially lower than that of the multiple ion monitoring method. Small quantities of a compound are therefore most accurately determined by adding a labelled version of the compound solely to act as a carrier, plus an internal standard giving an ion in common with the compound being measured. By this means 40 pg and 100 pg of methylated allobarbitone could be determined with coefficients of variation of 11.5 and 2.0%, respectively. Using only the labelled compound as internal standard, the corresponding values were 19.8 and 15.3% for the same quantities.
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  • 46
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    Biological Mass Spectrometry 2 (1975), S. 97-106 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectra and fragmentation pathways of some achiral and a number of chiral 1,4-benzodiazepine-2-ones, and those of their in vitro biotransformation products are reported and discussed. Various derivatives substituted in position 3 are shown to be useful for the determination of fragmentation pathways from low resolution spectra.
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  • 47
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    Biological Mass Spectrometry 2 (1975), S. 107-111 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metabolism by rat liver microsomes of the 2,4,6-trideuterio derivative of aniline mustard [N, N-di-(2-chloroethyl)aniline] in admixture with unlabelled material, has been studied. The resulting p-hydroxy derivative was isolated and examined by mass spectrometry. The extent of migration of deuterium from the p- to the m-position, determined from the ratio of trideuteriated to dideuteriated product, was 46%, but the protium and deuterium forms were hydroxylated at the same rate (zero isotope effect).
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  • 48
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    Biological Mass Spectrometry 2 (1975), S. 115-115 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 49
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Low molecular weight volatile organics extracted from the plasma of patients before and after hemodialysis were analyzed by high resolution capillary gas chomatographic mass spectrometric computer methods. The volatile components were collected on a polyphenyl ether solid adsorbent prior to analysis. Identification of components was achieved by mass spectrometry. Quantitaive changes were observed in both the plasma and dialysate composition with time. The method described provides a new means whereby the 100 or so low molecular weight organic volatiles of plasma can be monitored during the dialysis procedure.
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  • 50
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    Biological Mass Spectrometry 2 (1975), S. 164-167 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemical ionization mass spectra of eleven biomedically significant quaternary amimes are reported. The samples are converted to volatile compounds by known thermal decompositions. Chemical ionization of the compounds gives simple, easily identifiable spectra which are useful for the analysis of the original samples.
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  • 51
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    Biological Mass Spectrometry 2 (1975), S. ix 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 52
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    Biological Mass Spectrometry 2 (1975) 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 53
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    Biological Mass Spectrometry 2 (1975), S. 137-141 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reported synthesis of N-hydroxyphenmetrazine from phenmetrazine by the action of m-chloroperbenzoic acid could not be repeated. When the synthetic procedure was modified N-hydroxyphenmetrazine was obtained in low yield. The product had different properties from those claimed previously, but was identical to metabolically produced N-hydroxyphenmetrazine. It was characterized by means of thin-layer chromatography, combined gas chromatography and mass spectrometry, preparation of a t-butyldimethylsilyl derivative and oxidation to a mixture of nitrones. Mass spectrometry was also used to characterize these derivatives.
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  • 54
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    Biological Mass Spectrometry 2 (1975), S. 156-163 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectrometry has revealed the sugar sequence of a new saponoside isolated from the bark of Colubrina arborescens Mill (Rhamnaceae). The branched trisaccharide moiety if this saponoside is shown to be and O-β-L-arabinopyranosyl (1 → 2gal)-O-β-D-glucopyranosyl (1 → 3gal)-galactopyranose located on an as yet unknown genin. Mass spectra are presented for the permethylated saponoside, a permethylated trisaccharide and a partially methylated disaccharide, i.e. 3-β-D-glucopyranosylgalactose (C2 — OH), derived by partial hydrolysis. Further characterization of the mono-, di- and trisaccharides involved NaBH4 and NaBD4 reduction of the 4,6-dimethylgalactose reducing sugar moiety, followed by acetylation or trimethylsilylation.
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  • 55
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    Biological Mass Spectrometry 2 (1975), S. xi 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 56
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact mass spectrum (70 eV) of 26-trimethylsilyloxy-4-cholesten-3-one shows a base peak at m/e 196, attributable to combination of the trimethylsilyl group with a fragment of m/e 123 produced by cleavage across ring B. 18O labelling confirms that the fragment of m/e 196 contains the 3-oxygen atom, and 2H labelling indicates retention of the trimethylsilyl moiety. Similar ions are observed from other Δ4-3-ketones with sidechain trimethylsilyloxy groups: abundances depend on the site of substitution. The corresponding enol trimethylsilyl ethers are readily separable from the keto forms by gas-liquid chromatography, and afford mass spectra in which the molecular ions are abundant, while ions of m/e 196 are of only moderate intensity.
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  • 57
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 58
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A mass fragmentographic method for simultaneous measurement of unlabeled and deuterium labeled methadone in human plasma is described. This specific method has a lower sensitivity of about 16 pmol/ml with a coefficient of variation of less than 4%. The usefulness of the method was evaluated in studies on opiate dependent subjects undergoing methadone maintenance treatment. In one application methadone-d3 was given as a pulse dose during continuous treatment with unlabeled methadone and plasma levels of both species followed by mass fragmentography. The method will be of value in the study of methadone pharmacokinetics in the steady state and in other in vivo situations where multiple drug pools must exist.
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  • 59
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    Biological Mass Spectrometry 2 (1975), S. 201-203 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High resolution photoplate mass spectrometry has been used to examine crude goat urine extracts to determine the fate of organochlorine xenobiotics in these animals. Using a direct introduction temperature controlled probe the crude urine extracts were analyzed and the presence of oxygenated metabolites of 4-chlorobiphenyl and 4,4′-dichlorobiphenyl were confirmed in goats; analyses of urine extracts from goats injected with the commercial Aroclor mixtures 1254 and 5460 confirmed the formation of oxygenated penta-, tetra- and monochlorobiphenyl metabolites and an oxygenated dichloroterphenyl metabolite, respectively. This technique was particularly useful in the analysis of complex mixtures of metabolites.
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  • 60
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    Biological Mass Spectrometry 2 (1975), S. 215-218 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several slightly volatile or nonvolatile organic compounds were transformed directly in the solid sample inlet system into more volatile compounds by addition of an appropriate reagent to the sample. In this way, in several instances free organic acids could be obtained from their salts. A similar method was used to transform some amino acids into derivatives of diketopiperazine or of phthalic acid.
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  • 61
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    Biological Mass Spectrometry 2 (1975), S. 225-225 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 62
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method has been developed for quantification of phencyclidine [1-(1-phenylcyclohexyl)piperidine] in body fluids using gas chromatography chemical ionization mass spectrometry with selected ion recording. Pentadeuterated phencyclidine was synthesized and used as the internal standard. In developing the method it was discovered that phencyclidine thermally fragments to 1-phenylcyclohexene at elevated temperatures. The sensitivity and specificity of the method permits determination of 1 ng of phencyclidine in 1 ml of body fluid. The concentrations of the drug in blood samples from five individuals, who ingested unknown quantities of phencyclidine, were found to range from 50 ng/ml to 2.7 μg/ml. Following intravenous administration of 1 mg of phencyclidine hydrochloride to a 12.5 kg dog, the blood concentration of the drug peaked at 17.6 ng/ml and exhibited a half-life of approximately one hour. Two metabolities of phencyclidine were detected in human and dog urine after enzymatic hydrolysis. The metabolities were tentatively identified as 4-phenyl-4-piperidinocyclohexanol and 1-(1-phenylcyclohexyl)-4-hydroxy-piperidine by electron impact and chemical ionization mass spectral analysis of the metabolites and their trimethylsilyl derivatives. Structural confirmation was achieved by synthesis of the metabolities. A third metabolite was found in urine from rhesus monkeys and was tentatively identified as 1-(1-phenyl-4-hydroxycyclohexyl)-4-hydroxypiperidine.
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  • 63
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    Biological Mass Spectrometry 2 (1975), S. vii 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 64
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    Biological Mass Spectrometry 2 (1975) 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 65
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    Biological Mass Spectrometry 2 (1975), S. 229-253 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Publications from 1969 through 1974 reporting organic and spark source mass spectrometric studies on environmental samples have been compiled. Emphasis is placed on pollutants identified, but some methods and techniques are discussed. The 396 reports cited vary from those reporting hundreds of identified pollutants to those describing the analysis of only one sample containing one or a few pollutants. Reports concerning forensic, synthetic and standard samples, and analyses for drug residues, metabolites and degradation products are not included.
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  • 66
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    Biological Mass Spectrometry 2 (1975), S. 261-265 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pyrolysis gas chromatography mass spectrometry studies of the whole lyophilized microorganism Streptomyces longisporoflavus, an actinomycete, are reported. Identification of the pyrolysis products indicate that the vast majority arise from protein and carbohydrate origin. There is a paucity of lipid fragments evident. Some of the details of its biochemical composition evident in these results are compared with our previous similar studies on the bacteria Micrococcus luteus and Bacillus subtilis var. niger and suggest this actinomycete lies in biochemical complexity somewhere between the latter two organisms. Although the pyrolysis patterns of these three organisms possess considerable similarities, they are drastically different to that from the fungus Aspergillus niger.
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  • 67
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    Biological Mass Spectrometry 2 (1975), S. 272-275 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Melatonin containing three deuterium atoms in the 5-methoxy position has been synthesized by methylation of N-acetylserotonin with dideuterodiazomethane. The deuterated product was characterized by mass spectrometry and found to contain 90.8% of maximum possible deuterium incorporation. The major fragmentation patterns of melatonin under electron impact ionization are discussed with the aid of high resolution, deuterium labelling and metastable transition data.
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  • 68
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2,3,7,8-Tetrachlorodibenzo-p-dioxin and 2,3,7,8-tetrachlorodibenzo-p-dioxin-13C12 parent ion isotope cluster abundances are calculated on a multinomial probability basis for all possible isotope combinations. Parent negative ions \documentclass{article}\pagestyle{empty}\begin{document}$ \left[{\rm M} \right]^{\mathop - \limits_. } $\end{document} at m/e 322 and m/e 334 were selected for dual ion monitoring in the isotope dilution technique. Calculations, according to the Jaech's Method, are given for optimizing dual ion monitoring dwell time in the pulse counting mode at the femtogram level.
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  • 69
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methylphenidate undergoes partial thermal decomposition in the injection port of a gas chromatograph. This decomposition explains inconsistencies in some of the previously published mass spectra of the drug. The decomposition products were identified by gas chromatography mass spectrometry as methyl phenylacetate and a tetrahydropyridine. The extent of decomposition was found to be a function of the injector temperature and was also influenced by other factors, resulting in considerable variability. The ethyl ester analog behaved similarly. Derivatization with trifluoroacetic anhydride eliminates the thermal decomposition.
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  • 70
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    Biological Mass Spectrometry 2 (1975) 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 71
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A sensitive analytical method involving isotope dilution analysis with multilabeled standards and using field ionization mass spectrometry has been developed for the determination of methaqualone and its metabolie, 6-hydroxymethaqualone, in urine. The limit of sensitivity measured with urine samples is 200 pg/ml for the two compounds. Analysis of urines collected over 11 days following ingestion of a single 250 mg tablet of Mandrax™ by a human subject indicates that the slow phase of excretion of the two compounds has a half-life approximately 50 h long.
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  • 72
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    Biological Mass Spectrometry 2 (1975), S. 288-298 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Techniques are described for the computer reduction and identification of complex high resolution mass spectrometric data to yield qualitative and quantitative data for one hundred or more components in a complex mixture. The procedures described have been applied to direct insertion probe separations coupled with high resolution mass spectrometry. Two mass spectrometer computer systems are described in this paper. The basic techniques were developed at the University of Washington utilizing an A.E.I. MS-9 high resolution mass spectrometer, which was interfaced with a PDP-12 digital computer. The most recent system utilizes a Nova II computer interfaced to a Varian MAT 311 mass spectrometer. Programs were developed which were capable of determining the accurate mass (± 3 millimass) of up to 1000 ions per scan. High accuracy limited mass searches were first used to reduce the data. A correlation program was developed to resolve pure mass spectra from the composite mass spectral data using data obtained from the limited mass searches. A library search program was developed which used up to four major identifying masses and their relative abundances in addition to relative volatilization temperatures (probe) or relative retention times (gas chromatographic) for obtaining qualitative data. Quantitative data for each compound were obtained by comparing the total integrated ion current of one ion fragment to that of an internal standard. Instrumental and computer parameters are discussed with respect to the accuracy of the quantitative work. Final computer results gave compound identification and concentrations in μg/m3 or ppm. The use of this analytical technique for the analysis of complex mixtures of pollutants present in atmospheric aerosols is described.
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  • 73
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    Biological Mass Spectrometry 2 (1975), S. vii 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 74
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A generally applicable strategy for polypeptide sequencing has been developed which involves cleavage of a large peptide (for example, primary degradation peptides obtained by tryptic or cyanogen bromide cleavage of a protein) to a mixture of small peptides whose individual amino acid sequences are then determined without their prior isolation. This is accomplished by conversion of the peptide mixture into the corresponding mixture of O-trimethylsilylated polyamino alcohols through reduction of the N-acetylated peptide esters with lithium aluminum deuteride, followed by treatment with trimethylsilyldiethylamine. The conditions for the enzymatic or chemical cleavage were optimized to yield mixtures of peptides best suited for this technique and which represented complete overlap. Limited acid hydrolysis combined with a second experimen utilizing either an enzyme with broad specificity, a set of enzymes, or dipeptidyl aminopeptidase I on the original and/or Edman-degraded molecule was found to be the best choice. This sequencing strategy was evaluated using 0.4 to 1.4 μmol of peptides with known structures (ribonuclease S-peptide, glucagon) and then applied to primary degradation peptides of rabbit skeletal muscle actin up to twenty amino acids long (0.4 to 1 μmol per experiment).
    Additional Material: 5 Ill.
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  • 75
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    International Journal for Numerical Methods in Engineering 9 (1975) 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 76
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 252-252 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 77
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 259-270 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A class of approximations to the matrix linear differential equation is presented. The approximations range, in accuracy, from the simplest forward difference scheme to the exact solution. The infinite series defining the exponential matrix is used to ascertain the accuracy of the various approximations. A clear distinction is made between approximations to the system equations and the forcing function, with the forcing term being represented by a piecewise linear function. Special application is given to the equations arising in structural dynamics of the form For these structural dynamic equations, the measure of the energy of the system is used to analyse the stability of the numerical approximations.
    Additional Material: 3 Tab.
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  • 78
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 337-351 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The method of moments is a semidiscrete numerical method for solving partial differential equations. The method approximates the solution of a partial differential equation by a finite sum of products of two functions. One function in the product is an unknown function of a single variable and the other function (moment function) is a prescribed function in the remaining variables. Using variational technique we obtain a finite system of boundary value problems of ordinary differential equations for the unknown functions.The main goal of this paper is the study of the theoretical background and numerical effectiveness of the method of moments for solving linear partial differential equations on rectangular-like domains.The mathematical formulation of the method together with error estimates and the theory of optimal moment functions are given. If for the one-dimensional moment functions piecewise polynomials of degree K are used then finite element type error bounds are obtained for the approximate solution in two dimensions.We also consider the numerical implementation of the method through the factorization method and efficient initial value methods. Several numerical examples showing the efficiency of the method are presented.
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  • 79
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 617-629 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The number of equations which relate the mesh parameters (number of nodes, number of elements etc.) to each other is smaller than the number of unknowns contained therein. These rules are only applicable when several parameters of a defined mesh are known, but are unsuitable for use in the particularly interesting field of mesh projection unless additional inter-relationships can be found. Such relationships are given for uniform meshes in which besides the characteristics of the element type the ‘solidity value’ of the structure plays an important role.The equations are derived for two-dimensional triangular and quadrilateral elements and also for three-dimensional tetrahedral and hexahedral elements. The fact that these relationships are also suitable for estimating the parameters of any non-uniform mesh, discloses a wide field of application in the management of storage and in the control of programs for automatic mesh generation.
    Additional Material: 3 Ill.
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  • 80
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A method is described whereby the formulation for non-conforming bending elements includes the work dissipated across the inter-element boundaries. For the examples considered, this correction is shown to lead to a significant improvement in accuracy at little extra cost. Since the solution procedure is based on an iterative technique, the method would be particularly suitable if applied to non-linear problems.
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  • 81
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 727-731 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Additional Material: 3 Ill.
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  • 82
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 733-733 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 83
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    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 9 (1975) 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 84
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 765-773 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The paper examines two triangular finite elements used in plate bending analyses for which Lagrange multiplier techniques have been used to set up the necessary equations for the solution. These equations involve either equilibrium of the system or the inter-element compatibility. Starting from only the notions of equilibrium and continuity as used in the analyses of redundant structures, the paper proceeds to solutions of the same problems. It is found that end results are the same when the equations obtained from the minimization techniques are reduced by Gauss-elimination in partitioned from.
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  • 85
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 869-902 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The present study is intended as a guide for those who wish to undertake spectral analyses using Discrete Fast Fourier Transforms. Points of particular difficulty in using Fourier Transforms are derived in some detail. Experimental results are offered to illustrate the mathematical derivations. Finally the case of a signal with discontinuities along the time-axis is discussed.
    Additional Material: 21 Ill.
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  • 86
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 679-689 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper investigates the phenomenon of ‘noise’ which is common in most time-dependent problems. The emphasis is on the achievable accuracy that is obtained with various time-stepping algorithms and how this can be improved if noise is artificially damped to an acceptable level. A series of experiments are made where the space domain is discretized using the finite element method and the variation with time is approximated by several finite difference methods. The conclusion is reached that the Crank-Nicolson scheme with a simple averaging process is superior to the other methods investigated.
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  • 87
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 903-911 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Finite element methods are used to solve hydrodynamic lubrication problems involving compressible lubricants and porous bearing solids. The particular calculation scheme permits solution at high compressibility numbers (Λ 〉 100) to be obtained without any numerical difficulty. Finite element and finite difference results for the porous, gas lubricated journal bearing are presented and compared.
    Additional Material: 5 Ill.
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  • 88
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 938-943 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A comparison is made of the Crandall and Crank-Nicolson methods applied to a transient heat conduction problem with a convective boundary layer on its surface for a range of values of Nusselt modulus and Fourier modulus. A new equation is derived to handle the convective boundary condition. For reasonable accuracy requirements the Crank-Nicolson method gives superior performance with respect to accuracy.
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  • 89
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 948-949 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
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  • 90
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 129-147 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The formulation of finite element models on the basis of different variational principles is reviewed. The degrees-of-freedom of the elements are defined in an abstract way without the help of nodal points. In this manner it is possible to describe elements of arbitrary shape and accuracy. The formulation is confined to linear elasto-statics. For two-dimensional structures two hybrid element models are developed using Legendre polynomials on the element boundaries. Examples of plane stress problems are used to test the generation of convergence by increasing the accuracy of the elements vs. by increasing the number of elements.
    Additional Material: 10 Ill.
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  • 91
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 209-218 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Advances in technology and interest in limit state design have made the inclusion of non-linear effects, such as elasto-plastic behaviour, desirable in the analysis of many structures. Improvements in solution algorithms coupled with parallel developments in high speed digital computers have now made the practical solution of such problems possible. The paper presents numerical solutions to three-dimensional elasto-plastic problems illustrating the applicability of isoparametric elements and the order of computation times involved.
    Additional Material: 6 Ill.
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  • 92
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 39-50 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Finite element buckling analyses of plates are performed by means of quardrilateral elements having 12 degrees-of-freedom. It is found that if the plate is capable of appreciable transverse shear deformation, initial-stress stiffness matrices that represent the lateral dispalcement by cubic polynomials do not yield convergence to correct results. An initial-stress stiffness that works satisfactorily for both homogeneous and sandwich plates is formulated. A Fortran listing of the associated subroutine is provided.
    Additional Material: 4 Ill.
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  • 93
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper describes a practical implementation of the Galerkin finite element procedure for solving systems of parabolic partial differential equations with non-linear boundary conditions. This technique consists of finding an approximation in the form of a finite sum of cubic B-splines, which yield high-order accurate results, and consequently, solutions can be developed with remarkable precision and speed up to the steady state region where conventional finite difference methods often fail. In addition, the choice of mesh width and nodal spacing can be automatically determined for a predictor-corrector routine, thereby relieving the engineer of a great deal of ‘guess work’ that is normally characteristic of solving such problems.
    Additional Material: 3 Tab.
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  • 94
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 101-107 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The optimum profile of a beam is obtained by using finite elements with mathematical programming techniques. Beam profiles of preceding studies can be diplicated by the finite element method with the appropriate choice of numerical tolerance used in the convergence test.
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  • 95
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 149-168 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A cutting plane algorithm for the solution of generalized geometric programs with bounded variables is described and then illustrated by the detailed solution of a small numerical example. Convergence of this algorithm to a Kuhn-Tucker point of the program is assured if an initial feasible solution is available to initiate the algorithm. An algorithm for determining a feasible solution to a set of generalized posynomial inequalities which may be used to find a global minimum to the program as well as test for consistency of the constraint set, is also presented. Finally an application in optimal engineering design with seven variables and fourteen non-linear inequality constraints is formulated and solved.
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  • 96
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 235-238 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Additional Material: 3 Ill.
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  • 97
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 509-533 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper describes the computational aspects of an earlier analytical study1,2 of the problem of maximizing a linear combination of the natural frequencies of vibration of a turbine disc idealization subject to weight and fabrication constraints. The problem was formulated as an optimal control problem and solutions to the adjoint equations of the Pontryagin formalism obtained using perturbation techniques. These techniques transformed the problem to a non-linear program. This paper gives detailed computational solutions to the non-linear program which is characterized by pockets of relative optima. In addition, the dual problem of minimizing the weight subject to a frequency constraint is considered within the optimal control framework. The duality results are confirmed computationally for the two non-linear programs.A description of some practical procedures for improving the convergence characteristics of these highly non-linear programs is included.
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  • 98
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 415-432 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Details are given of a finite element scheme for the determination of the elastic buckling loads of thin flat plates of arbitrary shape under general kinematic and traction boundary conditions. The buckling loads are calculated using a triangular finite element with corner connections which is based on a previously derived variational principle combining both stresses and displacements. Numerical solutions are presented to a number of example problems, including plates with reinforcing members, and comparisons are made, where possible, with results from the finite element analyses of other authors and with exact or classical Rayleigh-Ritz solutions.
    Additional Material: 5 Ill.
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  • 99
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 401-413 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: It is shown that mathematical programming (MP) finds useful application in wing theory. This is illustrated by posing wing theoretical problems as programming problems within the framework of the linearized lifting surface theory. A great merit of programming techniques is their ability to accommodate inequality constraints in a problem. This feature allows a wing theoretician to expand into a domain of practical problems where qualitative constraints can be included into his formulations. A few numerical examples involving the Prandtl lifting line equation with equality and inequality constraints are given to show that the method works. Its extension to complex wing-body problems poses no conceptual difficulties, but requires further numerical experimentation.
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  • 100
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    International Journal for Numerical Methods in Engineering 9 (1975), S. 449-459 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The general stiffness matrix for a beam element is derived from the Bernoulli-Euler differential equation with the inclusion of axial forces. The terms of this matrix are expanded into a power series as a function of the two variables: the axial force, and; the vibrating frequency. It is shown that the first three terms of the resulting series, which are derived in the technical literature from assumed static displacement functions, correspond respectively to the elastic stiffness matrix, the consistent mass matrix, and the geometric matrix. Higher order terms up to the second order terms of the series expansion are obtained explicitly. Also a discussion is presented for establishing the region of convergence of the series expansion for the dynamic stiffness matrix, the stability matrix, and the general stiffness matrix.
    Additional Material: 1 Ill.
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