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  • 1985-1989  (2,093)
  • 1987  (2,093)
  • Analytical Chemistry and Spectroscopy  (1,177)
  • Organic Chemistry  (684)
  • Biochemistry  (133)
  • Genetics  (99)
Material
Years
  • 1985-1989  (2,093)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric nephrology 1 (1987), S. 69-75 
    ISSN: 1432-198X
    Keywords: Blood pressure ; Essential hypertension ; Genetics ; Epidemiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This paper presents a review of the genetic transmission of normal blood pressure and of essential hypertension. Familial aggregation of normal blood pressure has been reported in adults, in children and even in newborns. Blood pressure aggregation phenomenon, however, is the result of both a genetic component and shared environmental factors. More specific for each etiological factor were the studies of blood pressure aggregation in twins and in adopted children. Attention was focused on the Montreal Adoption Study. In essential hypertension, a Japanese study is reviewed showing the occurrence of hypertension in the offspring of hypertensive parents. The heterogeneity of essential hypertension is underlined and two of the multiple etiological factors are particularly considered for their genetic component: the response to salt intake and erythrocyte cation fluxes. The conclusion from the literature reviewed is that essential hypertension is a polygenic disease transmitted by polygenic systems.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric nephrology 1 (1987), S. 136-139 
    ISSN: 1432-198X
    Keywords: IgA nephropathy ; Genetics ; Complement ; C4 ; Glomerulonephritis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract C4 and factor B typing were performed in 37 pediatric patients with primary IgA nephropathy. Null alleles for C4B occurred with a frequency of 26% in patients, as compared to 15% in healthy controls (NS). The phenotype of C4B deficiency (homozygous C4B null), however, was found in 16% of patients and 4% of controls (P〈0.05). Comparison of observed C4B phenotypes with those predicted from the Hardy-Weinberg equilibrium also confirmed an excess of C4B deficiency (P〈0.0005). In contrast, there was no evidence of distortion in the frequencies of the C4A null allele or phenotype, or of the factor B alleles. The data suggest that C4B deficiency may be one of multiple interacting factors contributing to the development of this glomerulopathy.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric nephrology 1 (1987), S. 397-404 
    ISSN: 1432-198X
    Keywords: Cystic kidneys ; Genetics ; Prenatal diagnosis ; Linkage studies ; Potter sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Despite the high incidence of cystic kidney diseases, affected families are not usually well informed of the inheritance of these disorders. Genetic counselling must be based on precise diagnostic criteria. Detailed information on the different types of cystic kidney disease is summarized, including clinical features, pathology, radiology, prenatal diagnosis and the risk of recurrence. In addition, a genetic interpretation is given of the Caroli syndrome, Potter sequence as well as congenital hepatic fibrosis.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Pediatric nephrology 1 (1987), S. 436-438 
    ISSN: 1432-198X
    Keywords: Alport's syndrome ; Genetics ; Heterogeneity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The pattern of inheritance in Alport's syndrome has been controversial for some time. Recent studies have clarified the mode of inheritance in this disease. Alport's syndrome is a heterogeneous disorder made up of a number of genetically distinct syndromes, with an autosomal dominant, an X-linked dominant and a rare autosomal recessive form. Clinical analysis shows that there are many distinct forms with or without nerve deafness, and with early or late occurrence of end-stage renal disease.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 149 (1987), S. 36-42 
    ISSN: 1432-072X
    Keywords: Catabolite repression ; Genetics ; Malate dehydrogenase ; Molecular cloning ; Sequence ; CRP binding site ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The malate dehydrogenase gene of Escherichia coli, which is susceptible to catabolite and anaerobic repression, has been cloned using plasmic pLC32-38 of Clarke and Carbon (1976). The nucleotide sequence was determined of a 2.47 kbp fragment, containing the mdh structural gene. All information necessary for expression of the mdh structural gene was mapped within a 1.3 kbp SphI-BstEII fragment. Compared with the untransformed wild type, transformations with pUC19 vector, containing this fragment, gave up to 40-fold more malate dehydrogenase activity in both E. coli wild type and mdh mutant recipients. Catabolite repression was not affected in the transformants. A possible CRP binding site in the promotor region of the mdh gene provides evidence for a co-regulation with fumA gene, the structural gene of fumarase, which is also subject to catabolite repression. The structures for transcription initiation and termination were similar to those previously described for E. coli. Amino acid sequence homologies between pro- and eucaryotic malate dehydrogenases are discussed.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 146 (1987), S. 283-287 
    ISSN: 1432-1076
    Keywords: Pena-Shokeir I syndrome ; Facial anomalies ; Ankylosis ; Pulmonary hypoplasia ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two siblings whose clinical and pathologic features were consistent with the “Syndrome of camptodactyly, multiple ankyloses and pulmonary hypoplasia” originally described by Pena and Shokeir were examined at autopsy. Additional features were intrauterine growth retardation, immaturity of the central nervous system (CNS) and atrophy of skeletal muscles. Our data suggest that CNS damage may cause the complicated phenotypic abnormalities of the syndrome.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 146 (1987), S. 550-554 
    ISSN: 1432-1076
    Keywords: Epilepsy ; Genetics ; Myoclonic-astatic seizures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This paper presents case reports of patients suffering from myoclonic-astatic and stimulus-sensitive myoclonic seizures, respectively. It gives details of clinical and EEG data in the pertinent families. This is discussed in the context of controversial nosographic concepts of epilepsies with myoclonic seizures, and of the results of extensive family investigations. The findings demonstrate the decisive importance of hereditary factors in the pathogenesis of myoclonic and myoclonic-astatic epilepsy, the genetic background of which is probably polygenic.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 73 (1987), S. 440-444 
    ISSN: 1432-2242
    Keywords: Secale cereale L. ; Genetics ; α-Amylase ; Isozymes ; Modifiers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Fifteen inbred lines of rye, F1 and F2 progenies from crosses between lines were studied using polyacrylamide gel electrophoresis. Conventional genetic analysis of α-amylase zymograms showed that the 19 bands detected in the endosperm of germinating caryopses were controlled by three linked structural loci and one independent modifying locus, which influenced the electrophoretic mobility of isozymes. Two codominant alleles were found at the α-Amy1, α-Amy2 structural loci and the M-α-Amy modifying locus while the α-Amy3 locus had three alleles. Double-banded expression of the α-amylase alleles was probably due to the simultaneous presence of modified and unmodified forms of isozymes on the zymogram.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 74 (1987), S. 177-187 
    ISSN: 1432-2242
    Keywords: Barley ; Grain development ; Mutants ; Ultrastructure ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eleven Na-azide induced barley shrunken endosperm mutants expressing xenia (sex) were characterized genetically and histologically. All mutants have reduced kernel size with kernel weights ranging from 11 to 57% of the wild type. With one exception, the mutant phenotypes are ascribable to single recessive mutant alleles, giving rise to a ratio of 3∶1 of normal and shrunken kernels on heterozygous plants. One mutant (B10), also monofactorially inherited, shows a gene dosage dependent pattern of expression in the endosperm. Among the 8 mutants tested for allelism, no allelic mutant genes were discovered. By means of translocation mapping, the mutant gene of B10 was localized to the short arm of chromosome 7, and that of B9 to the short arm of chromosome 1. Based on microscopy studies, the mutant kernel phenotypes fall into three classes, viz. mutants with both endosperm and embryo affected and with a non-viable embryo, mutants with both endosperm and embryo affected and with a viable embryo giving rise to plants with a clearly mutant phenotype, and finally mutants with only the endosperm affected and with a normal embryo giving rise to plants with normal phenotype. The mutant collection covers mutations in genes participating in all of the developmental phases of the endosperm, i.e. the passage from syncytial to the cellular endosperm, total lack of aleurone cell formation and disturbance in the pattern of aleurone cell formation. In the starchy endosperm, varying degrees of cell differentiation occur, ranging from slight deviations from wild type to complete loss of starchy endosperm traits. In the embryo, blocks in the major developmental phases are represented in the mutant collection, including arrest at the proembryo stage, continued cell divisions but no differentiation, and embryos deviating only slightly from the wild type.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-1440
    Keywords: Blood Pressure ; Hypertension ; Salt ; Sodium ; Genetics ; Twin Model ; Salt Restriction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To examine the effect of genetic variance on blood pressure, sodium homeostasis, and its regulatory determinants, we studied 37 pairs of monozygotic twins and 18 pairs of dizygotic twins under conditions of volume expansion and contraction. We found that, in addition to blood pressure and body size, sodium excretion in response to provocative maneuvers, glomerular filtration rate, the renin-angiotensin system, and the sympathetic nervous system are influenced by genetic variance. To elucidate the interaction of genetic factors and an environmental influence, namely, salt intake, we restricted dietary sodium in 44 families of twin children. In addition to a modest decrease in blood pressure, we found heterogeneous responses in blood pressure indicative of sodium sensitivity and resistance which were normally distributed. Strong parent-offspring resemblances were found in baseline blood pressures which persisted when adjustments were made for age and weight. Further, mother-offspring resemblances were observed in the change in blood pressure with sodium restriction. We conclude that the control of sodium homeostasis is heritable and that the change in blood pressure with sodium restriction is familial as well. These data speak to the interaction between the genetic susceptibility to hypertension and environmental influences which may result in its expression.
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 113 (1987), S. 305-309 
    ISSN: 1432-1335
    Keywords: Formaldehyde ; Mutagenicity ; Metabolism ; Biochemistry ; Carcinogenicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Formaldehyde is a reactive chemical which undergoes spontaneous reactions with various cellular constituents. Mutagenicity data may be interpreted on the background of this behavior. Mice are better able to reduce the irritating effect of formaldehyde than rats and to reduce their ventilation rate when formaldehyde acts on the respiratory tract. Subacute exposure of rats to concentrations higher than 2 ppm inhibits mucociliary clearance of the nasal epithelium and leads to progressive histological and ultrastructural lesions at this site. The occurrence of squamous cell carcinomas of the nasal epithelium of rats after 2 years inhalation of 14.3 ppm formaldehyde (CIIT study) is probably the result of chronic and recurrent local toxicity; this is supported by species differences in susceptibility to the tissue damaging and carcinogenic effect of formaldehyde (rat, mouse, hamster). Data on formaldehyde-DNA interaction further support the argument that a direct risk extrapolation from the formaldehyde effects in rats to those expected for man is not possible.
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 1432-1459
    Keywords: Myoadenylate deaminase ; Histochemistry ; Biochemistry ; Neuromuscular diseases ; Exertional myalgia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A histochemical assay was routinely performed of myoadenylate deaminase (MAD) in muscle biopsy specimens. MAD was absent in 13 cases, i.e. 2.9% of the specimens. In 10 cases the deficiency was confirmed biochemically. The diagnoses in the 13 patients were: polyneuropathy (n=5), infantile spinal muscular atrophy (n=3), congenital myopathy with type 2 fibre atrophy, facioscapulohumeral myopathy, polymyositis, myotonic dystrophy and hyperornithinaemia with gyrate atrophy of the retina. In contrast, 35 unrelated patients presenting with exercise-related muscle cramps or pains showed normal histochemical MAD activity. The biopsy specimens in all of these patients were essentially normal and in none of them was the diagnosis of a neuromuscular disease made. The results failed to confirm the association of MAD deficiency with aches, cramps and pains or exertional myalgia.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Environmental biology of fishes 18 (1987), S. 249-256 
    ISSN: 1573-5133
    Keywords: Developmental rate ; Genetics ; Inheritance ; Meristic ; Salmonidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Deviations from morphological intermediacy in six first generation hybrids between three hatchery strains of rainbow trout, raised in a common environment, are reported. Hybrids have higher mean counts of four meristic characters than their maternal parental strain in a significantly greater number of cases (18 out of 24). Furthermore, eight of eleven hybrid indices are not intermediate. These results are discussed in reference to several mechanisms and models proposed to account for observed responses of meristic characters to environmental and genetic influences.
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 74 (1987), S. 439-444 
    ISSN: 1432-2242
    Keywords: Wheat ; Callus ; Regeneration ; Tissue culture ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Calli were initiated from immature embryos of nine lines of hexaploid wheat (Triticum aestivum L. em. Thell). These were the euploid lines Chinese Spring and Cappelle-Desprez, a line of Chinese Spring ditelocentric for the long arm of 4B, four substitution lines of Chinese Spring in which chromosome 4B has been replaced by its homologues from different wheat varieties and substituted into Chinese Spring and a substitution line of Besostaya I 4B into Cappelle-Desprez. The calli from these lines were found to differ in their growth rates and morphogenic and regenerative activities. The substitution of different 4B chromosomes into Chinese Spring significantly increased morphogenesis and shoot regeneration from callus. The potential for developing wheat lines with improved culture characteristics is discussed.
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  • 15
    ISSN: 1617-4623
    Keywords: NAD metabolism ; Regulation ; nadR ; Salmonella typhimurium ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nadR locus (99 min) controls the transcription of several genes involved with either the biosynthesis (nadAB) or recycling (pncB) of NAD in Salmonella typhimurium. Point mutations in this locus were found to cause defects either in the transport of nicotinamide mononucleotide (PnuA-), the regulation of nadAB (NadR-) or both transport and regulation (PnuA-NadR-). Deletions or insertions into nadR always resulted in the PnuA- NadR- phenotypes. Merodiploids constructed with various combiminations of PnuA-, NadR- or PnuA-NadR- strains indicate a single complementation group. The results suggest the NadR product is a bifunctional regulatory protein. Operon fusions to lacZ (nadR:: Mud1-8) were used to show that nadR is not autoregulated and is transcribed in a clockwise direction. The gene was also cloned and located within a 2 kb EcoR1-BglII fragment.
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  • 16
    ISSN: 1617-4623
    Keywords: E. coli ; Genetics ; Polysaccharide biosynthesis ; Secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Transposon and deletion analysis of the cloned K1 capsule biosynthesis genes of Escherichia coli revealed that approximately 17 kb of DNA, split into three functional regions, is required for capsule production. One block (region 1) is required for translocation of polysaccharide to the cell surface and mutations in this region result in the intracellular appearance of polymer indistinguishable on immunoelectrophoresis to that found on the surface of K1 encapsulated bacteria. This material was released from the cell by osmotic shock indicating that the polysaccharide was probably present in the periplasmic space. Insertions in a second block (region 2) completely abolished polymer production and this second region is believed to encode the enzymes for the biosynthesis and polymerisation of the K1 antigen. Addition of exogenous N-acetylneuraminic acid to one insertion mutant in this region restored its ability to express surface polymer as judged by K1 phage sensitivity. This insertion probably defines genes involved in biosynthesis of N-acetylneuraminic acid. Insertions in a third block (region 3) result in the intracellular appearance of polysaccharide with a very low electrophoretic mobility. The presence of the cloned K1 capsule biosynthesis genes on a multicopy plasmid in an E. coli K-12 strain did not increase the yields of capsular polysaccharide produced compared to the K1+ isolate from which the genes were cloned.
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  • 17
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987) 
    ISSN: 0887-6134
    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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  • 18
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. i 
    ISSN: 0887-6134
    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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  • 19
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amino acids can be identified unambiguously in form of their dansylated methyl esters by combination of thin-layer chromatography on polyamide and subsequent mass spectrometry without prior substance elution from the chromatographic polyamide carrier. The evaporation intensity of the amino acid derivatives is sufficient to get excellent mass spectra with significant structural information also with very small amounts of starting material (picomole level), which guarantee a high separation power in the TLC step. Besides the methylester derivatives, in part, products additionally methyl substituted at the sulfonamide nitrogen could be separated.
    Additional Material: 1 Tab.
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  • 20
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The simple combination of thin-layer chromatography on polyamide with subsequent mass spectrometry of the separated compounds together with the carrier material has been employed for unambiguous identification of individual dipeptides in a mixture. The dipeptides were analysed in the form of their dansyl methyl ester derivatives. The appearance of molecular ions in the electron impact mass spectra simultaneously with the ions dans-NH=CHR⌝+ indicating the corresponding N-terminal amino acid residue enables a rapid and sensitive structure elucidation of the dipeptides. The chromatography and mass spectrometry can be performed with 0.2-0.3 nmol dipeptide.
    Additional Material: 2 Ill.
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  • 21
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 357-362 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several classes of environmentally significant compounds were introduced into an ion trap detector (ITD) by capillary column gas chromatography, and the performance of the device as a gas chromatography/mass spectrometry (GC/MS) system was studied. The experiments conducted included studies of the precision of selected ion monitoring (SIM) measurements, the precision of relative ion abundance measurements in full mass range scans, the sensitivity and instrument detection limits in SIM and full mass range data acquisition, and the linear range of concentration calibration. It was observed that resolution may be lost and saturation may occur under certain conditions, and that the data system can report artifact ions under these conditions.
    Additional Material: 6 Ill.
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  • 22
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Brominated dioxins and dibenzofurans (PBDDs and PBDFs) are known contaminants in commercial fire retardant preparations. Further, they are formed in incineration processes involving polybrominated biphenyl and diphenylether fire retardants. This report presents the characterization of polybrominated dioxins and dibenzofurans. In particular, environmental monitoring methodology for PBDDs and PBDFs has been developed, and confirmation criteria for GC/MS analyses are presented.
    Additional Material: 3 Ill.
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  • 23
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 473-477 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Analysis of reports in the world's literature suggests that average sperm densities for groups of unselected males were relatively constant at about 108 million cells per ml prior to 1950. Subsequent to that time mean sperm densities appear to have declined. Regression analysis indicates the existence of significant negative correlations between mean sperm densities and production of synthetic organic chemicals among other parameters. Phthalate esters are one class of large volume organic chemicals that are known to disturb testicular function in laboratory animals. These compounds are also the most abundant man-made chemicals in the environment. Plots of the concentration of dibutylphthalate in the cellular fraction of ejaculates against either the sperm density or the total number of sperm for the same ejaculates gave two clusters of points. These clusters suggest the existence of two or more populations vis à vis phthalate metabolism; both of which show a negative correlation between phthalate concentration and sperm production.
    Additional Material: 4 Ill.
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  • 24
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 481-485 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We report a case of n-nonacosane storage disease, which went undiagnosed until the death of a 55-year-old farmer. Clinical, histological, and biochemical features are discussed. n-Nonacosane storage was identified by gas chromato-graphic-mass spectrometric analysis of different tissue extracts, n-nonacosane concentration reaching 1.2 mg g-1 of lung tissue and 0.32 mg g-1 of liver tissue. It was possible to rule out a work-induced intoxication, and n-nonacosane storage appeared to be accounted for by a lifelong, heavy consumption of unpeeled apples and Brussels sprouts.
    Additional Material: 4 Ill.
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  • 25
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new technique known as thermally-assisted fast atom bombardment (TA-FAB) has been applied to the analysis of a series of cyclic tetrapeptide mycotoxins in order to demonstrate the usefulness of the method for structural elucidation. TA-FAB uses saturated aqueous solutions of highly hydroxylated compounds, such as fructose, as alternatives to the usual viscous liquid matrices employed in conventional FAB. During the TA-FAB analysis, the probe tip is resistively heated causing diffeiences to occur in the desorption profiles for the analyte and the matrix ions enabling an optimization for analyte desorption as a function of temperature. In this study, direct comparisons are made between TA-FAB, conventional FAB, and electron impact ionization for the analysis of the Helminthosporium carbonum mycotoxins at the 1.5 μg level. The results demonstrate the superior capacity of TA-FAB to provide both molecular weight confirmation and significant fragmentation to aid in the structural elucidation of these important biomolecules.
    Additional Material: 5 Ill.
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  • 26
    Electronic Resource
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 517-521 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three glutathione conjugates of acetaminophen were characterized by fast atom bombardment/mass spectrometry (FAB/MS) and fast atom bombardment/mass spectrometry/mass spectrometry (FAB/MS/MS). The conjugates, 3-(glutathion-S-yl)acetaminophen, 3-(glutathion-S-yl)diacetaminophen and 3-(diglutathion-S-yl)diacetaminophen showed intense [MH]+ ions at m/z 457, 606 and 911, respectively. Only 3-(glutathion-S-yl)acetaminophen showed any fragmentation by FAB/MS. Structurally characteristic fragmentation was observed with all three conjugates when the [MH]+ ions were collisionally activated. The loss of the glycine (GLY) and glutamic acid (GLU) moieties indicated the presence of at least one glutathione (GSH) group. Multiple losses, some of which could only occur via cleavages in both GSH moieties, were observed with the diglutathione conjugate.
    Additional Material: 4 Ill.
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  • 27
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 549-553 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A GC-MS procedure has been developed for the quantitation in plasma and urine of rimantadine, an antiviral drug effective against type A influenza. The assay utilizes selective ion monitoring, methane negative ion chemical ionization (NCI) and stable isotope dilution. Sensitivity to NCI is effected by derivation of rimantadine with pentafluorobenzoyl chloride. The method has been used to quantitate plasma concentrations of rimantadine over a range from 4.2 ng/ml to 416 ng/ml, and urinary concentrations of rimantadine over a range of 21 ng/ml to 2077 ng/ml.
    Additional Material: 4 Ill.
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  • 28
    Electronic Resource
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 14 (1987), S. 127-129 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described to assign the positional series of methylene interrupted polyenoic acids, in complex mixtures, isolated from hydrolysed lipid extracts. It entails a simple comparison of the intensities of three ions of m/z 108, 150 and 192.
    Additional Material: 2 Ill.
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  • 29
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The behaviour of 1,1·,1″-phosphinothioylidinetrisaziridine (thiotepa) in water and aqueous salt solution of various acidity was studied by field ionization mass spectrometry (FI-MS), TLC and potentiometric titration. The rate of thiotepa hydrolysis increased with increasing thiotepa, or sodium chloride concentration, and with decreasing pH. As hydrolysis products of thiotepa, mono- and dichloro derivatives formed in neutral, salt-containing and acidic solution, tepa, and products formed by P—N bond cleavage and release of aziridine have been identified.
    Additional Material: 6 Ill.
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  • 30
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methodology for the qualitative and quantitative analysis of the anthelmintic fenbendazole and its metabolites in goat feces using electron impact (EI)/direct exposure probe (DEP)/mass spectrometric (MS) and tandem mass spectrometric (MS/MS) techniques is presented. Analyses were conducted on extracts from spiked feces and feces from animals treated per os with 5 mg fenbendazole/kg, with samples being collected at zero time and at twelve hour intervals for 144 h. The results of the EI/DEP/MS quantitation of these samples are compared to those for the same samples analysed by high pressure liquid chromatography (HPLC). Mass spectral data for fenbendazole and its metabolites are presented and the advantages of the use of EI/DEP/MS and/or DEP/MS/MS over HPLC are discussed. This methodology may be used as a confirmatory method for the HPLC analysis of fenbendazole and its metabolites or may be used as a method in its own right for the rapid qualitative and quantitative analysis of these compounds.
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  • 31
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Known and possible phenolic and primary and secondary amine metabolites of lidocaine were added to urine from drug-naive rats. These metabolites were derivatized in this aqueous medium by acetylation with acetic anhydride or by pentafluorobenzoylation with pentafluorobenzoyl chloride. The derivatives were simultaneously extracted into an organic solvent. The products were separated by gas chromatography (flame ionization detection for acetates and electron-capture detection for pentafluorobenzoates) and identified by combined gas chromatography/mass spectrometry. Mass spectral fragmentation pathways were readily deduced; diagnostic fragment ions were identified and were valuable for characterization purposes. Structural isomers could be distinguished on the basis of their GC retention times.Extractive derivatization using pentafluorobenzoyl chloride is an attractive analytical procedure for the identification of phenolic and dealkylated metabolites of lidocaine.
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  • 32
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 33
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    Biological Mass Spectrometry 14 (1987), S. 213-220 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermospray HPLC/MS analysis of the metabolites of arachidonic acid proved to be sensitive and specific. The compounds included were hydroxy-fatty acids (5-HETE, 12-HETE, and 15-HETE) and prostaglandins PGD2, PGE2, PGF2α, PGA2, PGA1, TXB2, and 6-Keto-PGF1α. Thermospray HPLC/MS analysis allows for simultaneous monitoring of each compound without the need for additional sample preparation or derivatization. The thermospray spectra for the metabolites exhibited [M + NH4]+ ions and fragment ions because of sequential loss of equivalents of H2O. HPLC/MS showed detection limits in the 0.5 to 5 ng range when using multiple ion detection for most of the metabolites. Post-column derivatization of these metabolites using trimethylanilinium hydroxide (TMAH) to form the methyl esters is also presented. This derivatization resulted in a gain in ion current by a factor of 3-6 for most compounds while adding potential specificity to the analysis. The thermospray spectra of the derivatives were nearly identical to the spectra of the free acid except the peaks were incremented by 14 daltons due to the methyl ester formation. The derivatization of the carboxylic acid group proved to be complete under thermospray conditions producing the maximum ion current and causing no compromise in operation of the interface.
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  • 34
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    Biological Mass Spectrometry 14 (1987), S. 649-651 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The identified urinary metabolites of male rats exposed to indan are: 1- and 2-indanone; 1-, 2- and 5-indanol; 2-and 3-hydroxyl-1-indanone; and cis- and trans-indan-1,2-diol. Indan causes kidney damage in male rats in a manner similar to the cyclic hydrocarbons cis- and trans-decalin and JP-10. Lesions produced by indan occur only in male rats and not in female or control rats.
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  • 35
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dinucleoside monophosphates bearing usual protecting groups at the exocyclic amino functions of the heterocyclic bases, the 5′-hydroxy group, the phosphate moiety and the O-6-position of the guanine ring have been analysed by FAB mass specrometry in the negative ion mode. These non-charged key intermediates for oligodeoxynucleotide synthesis exhibit very simple spectra in the mass range of m/z 400-1500 using tetra-ethylene glycol as matrix. Most of the observed ions could easily be assigned. Apart from deprotonated molecular ions sequence specific ions arising from C-O-P bond cleavage and ions derived from loss of protecting groups were observed. The simplicity of spectra interpretation makes FAB mass spectrometry to a rapid and valuable tool for unambiguous identification of dimeric synthons for oligonucleotide synthesis.
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  • 36
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    Biological Mass Spectrometry 14 (1987), S. 141-142 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 37
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    Biological Mass Spectrometry 14 (1987), S. 131-140 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mixtures of both synthetic and naturally occurring (human plasma) cholesteryl esters have been examined by capillary gas chromatography/mass spectrometry (GC/MS). A magnetic sector mass spectrometer was used and a variety of ionization modes were assessed with a view to obtaining structural information on intact cholesteryl esters. By employing ammonia as reagent gas, with negative ion scanning, spectra were produced from which the nature of steryl and fatty acyl moieties could be readily deduced. Analyses were performed at an ion source temperature of 300°C in order to maintain the integrity of the gas chromatographic profile. The technique described is of general use for the GC/MS analysis of steryl esters, particularly in conjunction with magnetic sector instruments.
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  • 38
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermospray spectra on a magnetic sector mass spectrometer, by definition measured at high accelerating voltages, are seen to be highly fragmented. This is rationalised in terms of the necessity to accelerate ions through a region of high pressure in the vicinity of the ion-collecting orifice at the spray volume, where ions may be energized by ion molecule collisions. In this region, a high percentage of the parent ion current is lost through the dispersion of the ion beam and by the collisional activation of molecular ions resulting in extensive fragmentation. The investigation of means by which these effects may be minimized has led to the construction of an improved sector thermospray source. Comparative results for gramicidin S demonstrate that its fragmentation is reduced and that the intensity of the protonated molecular ion is greatly enhanced.
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  • 39
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    Biological Mass Spectrometry 14 (1987), S. 183-185 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acetates of 12 positionally isomeric tetradecenols (Δ2-Δ13) have been prepared and their mass spectra measured without any prior chemical modification. Comparison of spectra of all the isomers has shown the variation in intensities of some predominant fragments with the position of the double bond on the 14 carbons chain. The mass spectra were interpreted in terms of the relative intensity ratio of the fragment ion peaks to locate the double bond positions. A procedure for elucidation of the positional isomerism of tetradecenyl acetates is given.
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  • 40
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    Biological Mass Spectrometry 14 (1987) 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 41
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    Biological Mass Spectrometry 14 (1987), S. 207-211 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eight normal subjects ingested 125 mg of p-tyramine-β,β-2H2 hydrochloride and the 3 h and following 21 h urine collections were analysed by mass spectrometry with selected ion monitoring for the deuterated metabolites: free and conjugated p-tyramine-β,β-2H2, free p-octopamine-β-2H1, free and conjugated p-hydroxyphenylacetic acid-α-2H1 and -α,α-2H2, and free p-hydroxymandelic acid-α-2H1. These metabolites accounted for 72% of the ingested label, of which conjugated p-tyramine and free p-hydroxyphenylacetic acid constituted 90%. Approximately 50% of the total deuterated tyramine and 70% of the total deuterated p-hydroxyphenylacetic acid were excreted in the first three hours, although there was considerable variation between individuals. The presence of a small amount of p-hydroxyphenylacetic acid-α-2H1 suggests that some exchange of deuterium occurred at the intermediate p-hydrophenylacetaldehyde stage.These results, based as they are on metabolites labelled with the stable isotope deuterium, ought to be more reliable than earlier studies in which unlabelled tyramine was ingested with the resultant metabolites, indistinguishable from their endogenous metabolic counterparts, being measured by fluorimetry or gas chromatography.
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  • 42
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    Biological Mass Spectrometry 14 (1987), S. 221-227 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Human exposure to aromatic amines may be monitored by measuring the amount of sulfinamide adduct bound to hemoglobin. In order to develop a sensitive and selective method for measuring aromatic amines present in low concentrations the mass spectra of the pentafluoropropionamide derivatives of a series of aromatic amines were determined under various ionization conditions. With electron ionization the aromatic amine derivatives typically yield intense molecular ions with fragmentation leading to elimination of C2F5 and COC2F5. Higher molecular weight polycyclic aromatic amines, e.g., 6-aminochrysene, give prominent molecular ions as well as intense ions corresponding to M-174 (loss of CNHCOC2F5). With positive chemical ionization using methane as reagent gas the derivatives give protonated molecular ions as the base peaks, as well as the associated ions at M + 29 and M + 41. Negative ion chemical ionization yields, primarily, peaks corresponding to the loss of HF from the molecular anions. Negative ion chemical ionization with selected ion monitoring is generally more suitable than positive chemical ionization or electron ionization for the quantitative analysis of aromatic amines present in biological samples in the mid femtomolar range. Exposure of human subjects to aromatic amines was determined via basic hydrolysis of the isolated sulfinic acid amide hemoglobin adducts. Analysis of the derivatized extracts by gas chromatography/negative ion chemical ionization/mass spectrometry demonstrated the presence of aniline, ortho-, meta-, and para-toluidine, 2-naphthylamine, and 4-aminobiphenyl. The hemoglobin adduct levels of these amines in both cigarette smokers and nonsmokers were determined. The mean values of the adduct levels of ortho- and para-toluidine, 2-naphthylamine, and 4-aminobiphenyl were higher in smokers than in nonsmokers, while the mean adduct values of aniline and meta-toluidine were similar in both groups. Adducts of 2-, 3-, 4-ethylaniline, 2,3-, 2,4-, 2,5-, 2,6-dimethylaniline, and 3-aminobiphenyl have been detected in smokers' blood. 1-Aminoanthracene, 9-aminophenanthrene, and 6-aminochrysene have not been detected. GC/MS procedures were also used to determine the extent of binding of aniline-2,3,4,5,6-d5 to hemoglobin in rats administered aniline-d5.
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  • 43
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    Biological Mass Spectrometry 14 (1987), S. 479-479 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 44
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The single dose pharmacokinetics of deuterium-labelled cannabinol (2H2-CBN) were evaluated in six male cannabis users with different degree of abuse after smoking an average dose of 19 mg and after intravenous administration of 20 mg CBN. Plasma levels were measured for up to 72 h with selected ion monitoring by GC/MS using 2H7-CBN as internal standard. The systemic availability of smoked CBN was found to be 39 ± 26% (min-max 6-65%). The mean plasma clearance was 19.1 ± 2.6 ml min-1 kg-1 and the volume of distribution was determined to 50 ± 23 1 kg-1. The apparent terminal half lives for CBN were 32 ± 17 h and 43 ± 29 h after intravenous administration and smoking, respectively.
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  • 45
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    Biological Mass Spectrometry 14 (1987), S. 533-534 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 46
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    Biological Mass Spectrometry 14 (1987), S. 523-531 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Derivatization of prostaglandins and thromboxane B2 using diethyl amino ethyl chloride and diethyl amino ethyl bromide improved thermospray HPLC/MS sensitivity. The derivatization was evaluated for prostaglandin A1, A2, D2, E2, F1α, F2α, and thromboxane B2. The derivatization reaction, thermospray operating conditions, and mode of detection were optimized to produce the most intense [M + H]+ or [M - H]- ions for the derivative. Derivatization was better than 99% complete in 1 hour at 75°C. No thermal degradation of the prostaglandins was observed. Positive thermospray ionization proved the mode most sensitive, enabling detection from 10 to 300 pg of each prostaglandin under multiple ion detection. The thermospray spectra exhibited intense [M + H]+ ions for the derivative with a few fragment ions from sequential losses of water from the [M + H]+ ion. Detection of a prostaglandin metabolite in plasma over the concentration range from 3 ppm to 30 ppb was possible using this derivatization.
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  • 47
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The gas chromatographic and mass spectrometric properties of leukotriene B4, 20-hydroxy-leukotriene B4 and 20-carboxy-leukotriene-B4 were investigated as their methyl ester trimethylsilyl, methyl ester allyldimethylsilyl and methyl ester tert-butyldimethylsilyl ethers. The gas chromatographic properties of the trimethylsilyl and tert-butyldimethylsilyl ether derivatives were good with respect to peak shape and sensitivity, whereas the allyldimethylsilyl ether derivative gave a lower sensitivity. The sensitivity defined as the quantity that could be passed through the gas chromatographic column.The three derivatives showed a mass spectrometric fragmentation pattern with cleavage of the C12—C13 bond as an important feature. Particularly, the allyldimethylsilyl ether derivative of the three compounds studied exhibited a high tendency for C12—C13 bond cleavage resulting in a fairly intense ion at m/z 435. However, the mass spectra indicated multiple fragmentation pathways due to the presence of double bonds, leading to decreased intensities of the high mass ions. A quantitative analysis by selected ion monitoring of the most intense high mass ions in the respective mass spectrum demonstrated that neither derivative would allow measurements in the low picogram range. Catalytic hydrogenation of the double bonds was performed and the methyl ester trimethylsiyl, methyl ester allyldimethylsilyl and methyl ester tert-butyldimethylsilyl ether derivatives of the reduced compounds were prepared. Saturation of the double bonds increased the gas chromatographic sensitivity for the three derivatives as well as the intensities of the high mass ions in their mass spectra. The high sensitivity that can be obtained by measurement of such high mass ions was demonstrated by quantification of leukotriene B4 in lung tissue samples by selected ion monitoring.
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  • 48
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    Biological Mass Spectrometry 14 (1987), S. 355-355 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 49
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    Biological Mass Spectrometry 14 (1987), S. 363-367 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The indoor air quality of the offices of smokers and nonsmokers was surveyed for volatile organic compound identities and concentrations. These results were examined to determine whether environmental tobacco smoke contamination could be distinguished from airborne pollutants outgassing from other sources. It was not possible to positively attribute volatile organic contaminants to environmental tobacco smoke. It was possible to distinguish between smokers' and nonsmokers' offices by determining airborne nicotine levels.
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  • 50
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxygen-enhanced negative chemical ionization MS is sensitive and specific for the detection of polychlorinated biphenyls (PCBs) without isobaric interferences (qualitative or quantitative) from congeners of higher levels of chlorination. The collision-induced dissociation (CID) spectra of the [M - Cl + O]- ion of 40 PCB congeners have been acquired on a triple quadrupole mass spectrometer.Qualitative relationships between structure of the congener and its CID spectrum suggest that reliable identification of PCB congeners is possible even where capillary column gas chromatographic separation is incomplete. Congeners with hydrogen atoms located para and meta to the biphenyl linkage show most abundant collision-induced loss of HCl, whereas congeners with a penta-chloro phenyl ring show least CID loss of HCl. Congeners IUPAC 105 and 121 have CID spectra suggesting a pathway for sequential loss of HCl and CO neutrals during the collision-induced dissociation of the [M - Cl + O]- ion of these molecules. Unambiguous identification of PCB congeners in natural materials will require a complete set of pure, synthetic PCB congeners: identification problems are illustrated using an extract of Northern Shark (dogfish) liver oil.
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  • 51
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    Biological Mass Spectrometry 14 (1987), S. 535-541 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A moving belt interface was used to identify budesonide metabolites, obtained from rat and mouse liver incubations, by liquid chromatography/mass spectrometry (LC/MS). The metabolites were separated on a small-bore C18 column with an ethanol/water gradient as mobile phase at a flow rate of 0.2 ml min-1. A spray device was used for deposition of the aqueous solvent on to the belt. Chemical ionization mass spectra were obtained with methane as the reagent gas. Deuterium-labelled budesonide, which was used to facilitate metabolite identification by the isotope cluster technqiue, was found to be slightly separated from the unlabelled analogue on the LC column. Incubations were also performed under 18O2 to elucidate the mechanism of a new metabolic pathway (16α, 17α-acetal splitting) and to confirm the oxidative nature of reactions leading to hydroxylated metabolites. The moving belt LC/MS technique afforded higher sensitivity, and gave more abundant MH+ ions of the compounds studied, than previously found by direct probe mass spectrometry. Phthalate ester background, partly from the polymide belt, complicated the identification of minor metabolites.
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  • 52
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    Biological Mass Spectrometry 14 (1987), S. 587-588 
    ISSN: 0887-6134
    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 14 (1987), S. 599-602 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the quantification in plasma of CP-55,940, a new non-opiate oral analgetic agent, using capillary gas chromatography/mass spectrometry. After extraction, derivation of the drug and a structural analog internal standard is carried out with trifluoracetyl imidazole. The derivative exhibited excellent gas chrornatographic properties. Electron impact yielded an abundant high mass ion whose monitoring permitted the sensitive and specific determination of CP-55,940 down to 0.5 ng ml-1.
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  • 54
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    Biological Mass Spectrometry 14 (1987), S. 613-616 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the quantification of tulobuterol in human plasma, based upon selective extraction and high resolution capillary gas chromatography-mass spectrometry. The mass spectrometric determination is based on selected ion monitoring of two fragment ions derived from the N,O-heptafluorobutyryl derivatives of tulobuterol and its internal standard, deschlorotulobuterol. The plasma work-up procedure consists of extraction of 1.0 ml alkalinised plasma with dichloromethane, back-extraction into an acidified aqueous phase, followed by a final extraction with dichloromethane after realkalinisation. The method gave interference-free and linear results. The between-assay variability is 4.7% CV at the 3.0 μg l-1 plasma concentration level. The assay permitted quantitative measurements down to 170 ng tulobuterol per litre of plasma and hence provided sufficient sensitivity for quantification of plasma levels after therapeutic doses.
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  • 55
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    Biological Mass Spectrometry 14 (1987), S. 627-632 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In phytochemical and chemotaxonomic research work mass spectrometry plays an outstandingly important role. Using gas chromatography/mass spectrometry (GC/MS) we established the chemotaxa of Tanacetum vulgare L. Chemotypes with essential oils countaining 60-90% of artemisia ketone, carveol, dihydrocarvone, myrtenol, umbellulone, terpinen-4-ol, davanone, and Tagetes species containing various essential oils can be clearly distinguished by their spectra; we examined many variations of Tagetes erecta, T. lucida, T. minuta, T. patula and T. tenuifolia. We have identified α-β-pinene-, 1,8-cineol-, linalool-, camphor-, nerol-, geraniol- and γ-gurjonene as components of Achillea distans L. Injecting the essential oil direct from the oil-secreting organs of T. minuta plants we identified using GC/MS 6-10 and 16% eugenol from the involucral bract and hypsophyll, respectively, as well as β-ocimene, dihydrotagetone, tagetone, Z- and E-ocimenones. In the course of studies on essential fatty acids Borago officinalis and Lappula squarrosa were selected from 70 species of the family Boraginaceae to obtain seed oil as a source of γ-linolenic acid, and for the PG synthesis we isolated several grams of γ-linolenic acid, as well as C18:4, i e. octadecatetraenic acid, from L. squarrosa on the basis of the mass spectra. From the seed oil of Aquilegia vulgaris C18:3 (5) from the oil of Limnanthes dougloasii C20:1 (5) and from the seed oils of Delphinium consolida and of Tropaeolum species (T. majus, T. minus, T. peregrinum) C20:1 (11) fatty acids were identified on the basis of spectra.
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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: Bile from rats treated with acetaminophen was analyzed by direct injection onto a thermospray liquid chromatography/mass spectrometry (LC/MS) system. Two conjugated metabolites of acetaminophen were separated by the high-pressure liquid chromatographic system and analyzed by mass spectrometry. The conjugates were identified as the glutathione-acetaminophen conjugate and the glucuronide-acetaminophen conjugate by comparison of the chromatographic retention times and the mass spectra to that of the synthetic standards. No evidence of acetaminophen metabolites was observed when bile samples were subjected to direct analysis by fast atom bombardment mass spectrometry.
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  • 57
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    Biological Mass Spectrometry 14 (1987), S. 733-736 
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 5 Ill.
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  • 58
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Direct analysis of unpurified urine from patients with β-ketothiolase deficiency and glutaryl-coenzyme A dehydrogenase deficiency was carried out by methylation and fast atom bombardment mass spectrometry. Previously unidentified signals consistent with unusual acylcarnitines were detected. In the former disease, thermospray liquid chromatography/mass spectrometry analysis confirmed the identification of tiglylcarnitine and differentiated it from a biological isomer, 3-methylcrotonylcarnitine. In glutaric aciduria, glutarylcarnitine was confirmed by detection of glutaric acid liberated upon base hydrolysis of a purified acylcarnitine fraction. The discovery of these metabolites suggests that L-carnitine therapy might be beneficial for the enhanced excretion of toxic metabolites that accumulate in patients with these disorders.
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  • 59
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    Journal of Chemometrics 1 (1987) 
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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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  • 60
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    Journal of Chemometrics 1 (1987), S. 1-2 
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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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  • 61
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    Journal of Chemometrics 1 (1987), S. 3-6 
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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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  • 62
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    Journal of Chemometrics 1 (1987), S. 7-18 
    ISSN: 0886-9383
    Keywords: Kalman filter ; Calibration ; Curve resolution ; Parameter estimation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The application of the Kalman filter to the solution of a variety of problems in analytical chemistry is reviewed. Five examples are selected from the literature to illustrate the use of Kalman filtering techniques for obtaining least-squares estimates fo several parameters of analytical importance. These examples include multicomponent curve resolution and concentration estimation, correction for variable background responses, calibration with drift compensation, and estimation of kinetic parameters for first-order reactions and for heterogeneous charge-transfer reactions. An adaptive Kalman filtering technique is required for the solution of the background correction problem, and the extended Kalman filter algorithm is required for the solution of the nonlinear kinetic problems. For each case, the results that were obtained are summarized, and some advantages of Kalman filtering over traditional least-squares approaches are discussed.
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  • 63
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    Journal of Chemometrics 1 (1987), S. 19-31 
    ISSN: 0886-9383
    Keywords: Calibration ; Indirect calibration ; Multivariate ; Matrix decomposition ; PLS ; PCR ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Partial least squares (PLS) modeling is an algorithm for relating one or more dependent variables to two or more independent variables. As a regression procedure it apparently evolved from the method of principal components regression (PCR) using the NIPALS algorithm, which is similar to the power method for determining the eigenvectors and eigenvalues of a matrix. This paper presents a theoretical explanation of the PLS algorithm using singular value decomposition and the power method. The relation of PLS to PCR is demonstrated, and PLS is shown to be one of a continuum of possible solutions of a similar type. These other solutions may give better prediction than either PLS or PCR under appropriate conditions.
    Additional Material: 4 Tab.
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  • 64
    ISSN: 0886-9383
    Keywords: Principal component analysis ; Singular value decomposition ; Factor analysis ; Rank determination ; Eigenvector analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The distribution of error eigenvalues resulting from principal component analysis is deduced by considering the decomposition of an error matrix in which the errors are uniformly distributed. The derived probability function is \documentclass{article}\pagestyle{empty}\begin{document}$$ P(\lambda ^0 _j) = N(r - j + 1)(c - j + 1) $$\end{document} Where λ0j is the jth error eigenvalue, r and c are the numbers of rows and columns in the data matrix, and N is the normalization constant. This expression is tested and validated by investigations involving model data. The distribution function is used to determine the number of factors responsible for various sets of spectroscopic data taken from the chemical literature (including nuclear magnetic resonance, infrared and mass spectra).
    Additional Material: 1 Ill.
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  • 65
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    Keywords: Curve resolution ; Liquid chromatography ; Accuracy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The performance of curve resolution and iterative target transformation curve resolution in quantitative liquid chromatography with a diode array detector is evaluated. Quantitative accuracy of the elution profiles obtained for two- and three-component mixtures has been evaluated as a function of spectral similarity, chromatographic resolution and ratio of the peak areas, using a number of simulations analysed by an analysis of variance. The results obtained by simulation are compared and validated with the results obtained for the separation of phenylene diamines in reversed phase liquid chromatography and proteins in gel permeation liquid chromatography. The results that were obtained are summarized and the chromatographic implications are discussed.
    Additional Material: 3 Ill.
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  • 66
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    Keywords: Multi-way array ; Multiorder array ; Principal components ; PLS ; Multivariate calibration ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Lohmöller-Wold decomposition of multi-way (three-way, four-way, etc.) data arrays is combined with the non-linear partial least squares (NIPALS) algorithms to provide multi-way solutions of principal components analysis (PCA) and partial least squares modelling in latent variables (PLS).The decomposition of a multi-way array is developed as the product of a score vector and a loading array, where the score vectors have the same properties as those of ordinary two-way PCA and PLS. In image analysis, the array would instead be decomposed as the product of a loading vector and an image score matrix.The resulting methods are equivalent to the method of unfolding a multi-way array to a two-way matrix followed by ordinary PCA or PLS analysis. This automatically proves the eigenvector and least squares properties of the multi-way PCA and PLS methods.The methodology is presented; the algorithms are outlined and illustrated with a small chemical example.
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  • 67
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    Journal of Chemometrics 1 (1987), S. 73-73 
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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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  • 68
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    Journal of Chemometrics 1 (1987), S. 75-75 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 69
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    Journal of Chemometrics 1 (1987), S. 74-74 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 70
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    Journal of Chemometrics 1 (1987) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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  • 71
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    Journal of Chemometrics 1 (1987), S. 77-77 
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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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  • 72
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    Journal of Chemometrics 1 (1987), S. 79-90 
    ISSN: 0886-9383
    Keywords: Numerical deconvolution ; Peak resolution ; Peak separation ; Iterative deconvolution ; Jansson's method ; Super-resolution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Severely overlapped gas chromatographic peaks can be resolved using Jansson's method. Jansson's method is an iterative nonlinear deconvolution technique and consists of Van Cittert's algorithm with the relaxation factor a function of the kth estimate of the peak shape. The maximum peak amplitude of the instrument and peak non-negativity serve as constraints to improve the peak estimate. Super-resolution is achieved without significantly degrading the chromatogram signal-to-noise ratio. The method only requires a knowledge of the instrument impulse response function and maximum peak height.
    Additional Material: 7 Ill.
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  • 73
    ISSN: 0886-9383
    Keywords: NIR ; Fast Fourier transform ; Principal component analysis ; Discrimination ; Baking quality ; Wheat ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Digitalized continuous near infra-red reflectance (NIR) spectra are composed of a great number of data which must be reduced for microcomputer mathematical treatment. The sequence ‘fast Fourier transform preceding principal component analysis’ was tested to perform data size reduction without a large loss of information. The method was applied on a collection of wheat spectra composed of 351 data. Ten resulting data, which described 99.5% of the total variance, were kept. The relevance of the method was estimated by the ability of the resulting data (i) to regenerate the original signal, and (ii) to discriminate the baking quality of the wheat by stepwise multiple discriminant analysis. The average difference between initial and regenerated spectra was -2.4 × 10-3 log (1/R) units and the standard deviation was 1.16 × 10-3 log (1/R) units. The discrimination treatments gave 89.9% of well classified samples for the calibration test and 90.5% for the prediction test. The application of these mathematical treatments to other continuous signals is discussed.
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  • 74
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    Journal of Chemometrics 1 (1987), S. 91-101 
    ISSN: 0886-9383
    Keywords: Factor analysis ; Retention indices ; Model ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Retention indices for 18 monomeric stationary-phase solvents and 33 organic solutes are factor analyzed. Six factors reproduce the data matrix near experimental error. The solvents diglycerol and zonyl E-7 are shown to be highly unique, whereas none of the solutes behaves uniquely. Combination sets of solvent vectors and of solute vectors from the data matrix lead to models having errors within experimental error. Basic factors which might influence the solute - solvent interactions are identified by the least-squares method of target testing. For the solvents, a number of properties, including McReynolds' constants and molecular weight, test successfully. For the solutes, carbon number and group dipole moment are representative properties which test successfully. The best combination of solvent basic factors gives errors about twice the experimental error. Combination sets composed only of McReynolds' constants do not model the data well.
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  • 75
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    Journal of Chemometrics 1 (1987), S. 111-120 
    ISSN: 0886-9383
    Keywords: Principal component analysis ; Submatrix analysis ; Spectroscopy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the treatment of spectroscopic data by principal component analysis, correct determination of the dimensionality of the data is essential. Submatrix analysis, which involves preliminary analysis of subsets of the data matrix, is described, and shown to be valuable in determining both the size of the factor space and estimates of equilibrium constants in the system, even for data containing abnormally large experimental error.
    Additional Material: 4 Ill.
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  • 76
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    Journal of Chemometrics 1 (1987), S. 135-135 
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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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  • 77
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    Journal of Chemometrics 1 (1987), S. 136-136 
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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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  • 78
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    Journal of Chemometrics 1 (1987), S. 121-134 
    ISSN: 0886-9383
    Keywords: Multivariate calibration ; NIR ; Cluster analysis ; Experimental design ; Sample selection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A procedure for selecting samples to use in multivariate calibration, inspired by a paper by Zemroch, is proposed. The method developed is designed for multicollinear data and is based on cluster analysis. It selects among availabe spectra the samples to submit to chemical analysis and calibration. The method is tested on an example from NIR spectroscopy of biscuit dough pieces.
    Additional Material: 11 Ill.
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  • 79
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    Journal of Chemometrics 1 (1987), S. 136-136 
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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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  • 80
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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  • 81
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    Journal of Chemometrics 1 (1987), S. 137-137 
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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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  • 82
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    Journal of Chemometrics 1 (1987), S. 157-173 
    ISSN: 0886-9383
    Keywords: Gas chromatography ; Simplex ; Barycentric co-ordinates ; Discriminant analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper proposes an elegant, yet straightforward, model for classifying linear mixtures. A linear mixture is defined as a random vector y in which the variable are a (non-negative) weighted average of corresponding variables, assumed to characterize g component groups. These weights are referred to as ‘mixing proportions’. The model seeks to identify the mixture constituents and estimate the mixing proportions. It is demonstrated within the context of high resolution gas chromatography and the problem of identifying the constituents in polychlorinated biphenyl mixtures.
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  • 83
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    Journal of Chemometrics 1 (1987), S. 175-183 
    ISSN: 0886-9383
    Keywords: Deconvolution ; Jansson's method ; Peak resolution ; Numerical deconvolution ; Super resolution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In a previous paper,1 Jansson's method was used to deconvolve overlapped gas chromatographic peaks. It was found that this method gave improved performance over conventional techniques such as perpendicular drop and shoulder quantitation.2,3 This paper will present the results of a comprehensive test of Jansson's method using several sample mixtures. These results will be compared to what can be obtained by using shoulder quantitation, perpendicular drop or an instrument with a longer column. A relatively large number of tests will be performed for each of the four mentioned methods of peak resolution, so there will be a reasonable statistical basis for the goodness of Jansson's method to resolve fused gas chromatographic peaks for a given set of instrument conditions. A brief review of Jansson's method and the modeling of a gas chromatographic process will also be presented.
    Additional Material: 6 Ill.
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  • 84
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    Journal of Chemometrics 1 (1987), S. 139-155 
    ISSN: 0886-9383
    Keywords: Chemical information systems ; Machine-readable structure representation ; Registration search ; Structure search ; Substructure search ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper decribes the development and current state-of-the-art in computerized systems for the storage and retrieval of chemical structure information. The main types of machine-readable structure representation  -  fragmentation codes, linear notations and connection tables  -  are described, together with the retrieval algorithms which are used to provide structure and substructure search facilities. Current research work in chemical structure retrieval includes the development of techniques for the representation and searching of the generic structures which occur in chemical patents, for searching files of three-dimensional structures, for ranking searches designed to identify compounds structurally similar to a given query compound, and the use of parallel computers to increase the efficiency of substructure searching. Chemical structure handling techniques are also applicable in a range of application areas, including chemical reaction indexing, computer-aided synthesis design and structure elucidation, and substructural analysis methods for the study of quantitative structure - activity relationships.
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  • 85
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    Journal of Chemometrics 1 (1987), S. 197-197 
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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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  • 86
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    Journal of Chemometrics 1 (1987), S. 185-196 
    ISSN: 0886-9383
    Keywords: Cross-validation ; Partial least squares ; Two-sample location ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for statistical analysis of two independent samples with respect to difference in location is investigated. The method uses the partial least squares projections to latent structures (PLS) with cross-validation. The relation to classical methods is discussed and a Monte Carlo study is performed to describe how the distribution of the test-statistic employed depends on the number of objects, the number of variables, the percentage variance explained by the first PLS-component and the percentage missing values. Polynomial approximations for the dependency of the 50 per cent and the 5 per cent levels of the test-statistic on these factors are given. The polynomial for the 50 per cent level is complicated, involving several first-, second- and third-degree terms, whereas the polynomial for the 5 per cent level is dependent only on the number of objects and the size of the first component. A separate Monte Carlo experiment indicates that a moderate difference in sample size does not affect the distribution of the test-statistic. The multi-sample location problem is also studied and the effect of increasing the number of samples on the test-statistic is shown in simulations.
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  • 87
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    Journal of Chemometrics 1 (1987), S. 198-198 
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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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  • 88
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    Journal of Chemometrics 1 (1987), S. 197-198 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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    Journal of Chemometrics 1 (1987), S. 198-198 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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  • 90
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    Journal of Chemometrics 1 (1987), S. 199-199 
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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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  • 91
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    Journal of Chemometrics 1 (1987) 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Topics: Chemistry and Pharmacology
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  • 92
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    Journal of Chemometrics 1 (1987), S. 201-219 
    ISSN: 0886-9383
    Keywords: Multivariate ; Calibration ; PLS ; Regression ; Spectroscopy ; Selectivity ; Outliers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper illustrates some advantages of indirect multivariate calibration over conventional calibration: selectivity enhancement and outlier detection. Partial least squares (PLS) calibration is applied for quantitative analysis in the presence of interferences that would make both conventional single-wavelength calibration and direct multicomponent analysis impossible. The PLS algorithm is illustrated graphically, and the importance of outlier detection is demonstrated.
    Additional Material: 9 Ill.
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  • 93
    ISSN: 0886-9383
    Keywords: Pattern recognition ; SIMCA ; PCA ; Classification ; Bacteria ; Pyrolysis mass spectra ; Recall ; Cross-validation ; Indicator function ; Pseudo random data sets ; Leave-x-out ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: As part of a critical evaluation of the pattern recognition method SIMCA, three data sets containing pyrolysis mass spectra from bacteria were analysed using the SIMCA classifier. Each set consisted of two classes, Pseudomonas and Serratia bacteria, each class containing ten mass spectra and each mass spectrum having 285 spectral features.The results indicate that for these py-MS data sets, with low object/feature ratio, the SIMCA classifier produces satisfactory results at the first classification level. At the second level, however, the classification results are not reliable, even after deleting outliers. A comparison of the cross-validation method and Malinowski's indicator function for the determination of the number of significant principal components showed that the cross-validation method is less stable and therefore less reliable than the indicator function.
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  • 94
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    Journal of Chemometrics 1 (1987), S. 221-230 
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    Keywords: Pattern recognition ; SIMCA ; PCA ; Classification ; Recall ; Cross-validation ; Indicator function ; Leave-x-out ; Pseudo random data sets ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The SIMCA pattern recognition method has been evaluated with pseudo random data sets. The number of objects varied from 5 to 50 and the number of features from 5 to 300.First, the determination of the significant number of PCs in the SIMCA models by the cross-validation method was compared with the indicator function. The results showed that for the lower dimensions (≤ 15 objects or ≤ 15 features) the indicator function produces more reliable results.Second, the classification results with SIMCA were analysed for data sets with two equally sized classes and a varying number of objects and features, using the recall function as the evaluation criterion. The results showed that the SIMCA classifier produces reliable results at the first classification level, even for a low object/feature ratio (5/300). However, at the second level the classification performance of SIMCA decreases rapidly with an increasing number of features, even when the data set consists of two very well separated classes and little random error.
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  • 95
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    Journal of Chemometrics 1 (1987), S. 243-245 
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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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  • 96
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
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    Journal of Chemometrics 1 (1987), S. 246-247 
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    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: STATA: VERSION 1.5, available from Computing Resources Center, 10801 National Boulevard, Los Angeles, CA 90064, U.S.A. Telex: 263199 STATAPC. Published by the Computing Resources Center, 1986. Basic version, for data management, data presentation, statistical testing, estimation, including linear regression, ANOVA and ANCOVA, with two program collections (written in the STATA programming language ) for (1) parametric and non-parametric tests and (2) generation of statistical graphs. Price: $395 in North America, $470 elsewhere (academic discount price in North America: $265).STATE GRAPHICS MODULE, for high-resolution statistical graphics, including one-way and two-way scatter plots, scatter-plot matrices, box plots, bar and pie charts, multiple imaging and overlays. Price: $195 in North America, $270 elsewhere (academic discount price in North America: $130).
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    Journal of Chemometrics 1 (1987), S. 248-249 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 99
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 1 (1987), S. 250-254 
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 100
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
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