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  • 1990-1994  (1,807)
  • 1980-1984
  • 1991  (1,807)
  • Analytical Chemistry and Spectroscopy  (1,511)
  • Atomic, Molecular and Optical Physics  (238)
  • Nuclear reactions
  • Ultrastructure
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Material
Years
  • 1990-1994  (1,807)
  • 1980-1984
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Fluoride effects on leaf cell ultrastructure of olive trees growing in the vicinity of the Aluminium Factory of Greece (1991)
    Springer
    Trees 5 (1991), S. 83-89 
    Details
    ISSN: 1432-2285
    Keywords: Air pollutants ; Chloroplasts ; Fluoride ; Olive tree leaves ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Leaves of olive trees growing in the vicinity of the Aluminium Factory of Greece were ultrastructurally investigated in order to determine any malformations caused by environmental air pollutants, especially hydrogen fluoride, in comparison with control samples and normal seasonal senescence. Estimation of some elements accumulated by these leaves showed that they contained high amounts of F and Al attributable to the operation of the nearby factory. The most seriously effected cell components were found to be the mesophyll chloroplasts that show a dilation of the intrathylakoid space, increase of the number of plastoglobuli, discoloration of plastoglobuli, accumulation of large starch grains and an overall disorganized appearance of the organelle. The nuclear crystalloid inclusions have unusual shapes, while the vacuoles contain a fibrillar/granular material that increases their electron density. It is concluded that the ultrastructural malformations are caused by a combination of environmental stresses and air pollutants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227489
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of dopamine agonist medication on prolactin producing pituitary adenomas (1991)
    Springer
    Virchows Archiv 418 (1991), S. 439-446 
    Details
    ISSN: 1432-2307
    Keywords: Bromocriptine ; Pituitary neoplasm ; Prolactin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Conventional light microscopy, immunocyto-chemistry, electron microscopy and in situ hybridization were used to evaluate the effect of dopamine agonists (bromocriptine-LAR and bromocriptine) on the morphology of surgically removed prolactin (PRL)-producing pituitary adenomas. Dopamine agonist therapy resulted in decrease of serum PRL, clinical improvement and tumour shrinkage. Using light and electron microscopy cellular atrophy, interstitial and perivascular fibrosis were noted; in several tumours connective tissue accumulation was pronounced. The cellular response was not uniform. In some adenomas populations of large cells and small cells were distinguished. The large cells contained immunoreactive PRL and expressed the PRL gene indicating resistance to dopamine agonists. It appears that these cells retained the potential to secrete PRL and proliferate despite exposure to dopamine agonists. In the small cells, PRL immunoreactivity and PRL gene expression decreased providing evidence that both PRL release and synthesis were blocked. Small cells can persist in tumours after discontinuation of dopamine agonist medication suggesting these small cells are irreversibly suppressed and are not capable of regaining their endocrine function and proliferative capability. The formation of irreversibly suppressed PRL cells may explain why some PRL-producing adenomas do not recur after withdrawal of dopamine agonists.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01605931
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructure of oesophageal melanocytosis (1991)
    Springer
    Virchows Archiv 418 (1991), S. 515-522 
    Details
    ISSN: 1432-2307
    Keywords: Oesophagus ; Melanocyte ; Melanoma ; Ultrastructure ; Endoscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Four examples of an endoscopically detected oesophageal melanotic lesion were examined by light microscopy, light microscope histochemistry and transmission electron microscopy, and were compared with 13 control samples of normal oesophageal epithelium. By light microscopy, pigmented melanocytes lacking atypia and mitoses were observed amongst the keratinocytes in the basal layer of the oesophageal mucosa. Junctional activity was absent. The mechanism of pigmentation was studied and found to consist of: an increase in the number of melanocytes in the basal layer of the mucosa, an increase in the quantity of melanin in these melanocytes, transfer of melanin from melanocytes to keratinocytes and to macrophages and fibroblasts in the tunica propria. Since all the lesions demonstrated increased numbers of both melanocytes and melanosomes, the term oesophagealmelanocytosis rather thanmelanosis is suggested, to emphasise the essential character of the lesion as a cellular proliferation. The value of sampling these pigmented lesions during endoscopy is emphasised as a means of obtaining well-preserved material for the evaluation of a lesion which some authorities have viewed as a possible precursor for oesophageal malignant melanoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606502
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  • 4
    Electronic Resource
    Electronic Resource
    Ultrastructural abnormalities of mitochondria and deficiency of myocardial cytochromec oxidase in a patient with ventricular tachycardia (1991)
    Springer
    Virchows Archiv 419 (1991), S. 63-68 
    Details
    ISSN: 1432-2307
    Keywords: Mitochondrial cardiomyopathy ; Ultrastructure ; Cytochromec oxidase deficiency ; Ventricular tachycardia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 30-year-old woman presented with lifethreatening ventricular tachycardia without overt heart disease. Ultrastructural investigation of endomyocardial biopsy disclosed abnormally structured and often enlarged mitochondria. Morphometry revealed the ratio of volume density of mitochondria to myofibrils to be markedly increased to 0.667 as compared with five controls (mean: 0.46; range: 0.445–0.479). Investigation of mitochondrial respiratory chain enzymes revealed a 90% reduction in activity of cytochromec oxidase. Our data suggest that mitochondrial cardiomyopathy may induce malignant ventricular arrhythmias.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600154
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  • 5
    Electronic Resource
    Electronic Resource
    Secretory tapetum of Brassica oleracea L.: polarity and ultrastructural features (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 28-35 
    Details
    ISSN: 1432-2145
    Keywords: Tapetal cells ; Brassica oleracea L ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructure of the secretory, binucleate tapetum of Brassica oleracea in the micro spore mother cell (MMC) stage through to the mature pollen stage is reported. The tapetal cells differentiate as highly specialized cells whose development is involved in lipid accumulation in their final stage. They start breaking down just before anther dehiscence. Nuclei with dispersed chromatin, large nucleoli and many ribosomes in the cytoplasm characterize the tapetal cells. The wall-bearing tapetum phase ends at the tetrade stage. The dissolution of tapetal walls begins from the inner tangential wall oriented towards the loculus and proceeds gradually along the radial walls to the outer tangential one. The plasmodesmata transversing the radial walls between tapetal cells persist until the mature microspore, long after loss of the inner tangential wall. After wall dissolution, the tapetal protoplasts retain their integrity and position within the anther locule. The tapetal cell membrane is in direct contact with the exine of the microspores/pollen grains and forms tubular evaginations that increase its surface area and appear to be involved in the translocation of solutes from the tapetal cells to the microspores/ pollen grains. The tapetal cells exhibit a polarity expressed by spatial differentiation in the radial direction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194568
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  • 6
    Electronic Resource
    Electronic Resource
    Brassica napus pollen development during generative cell and sperm cell formation (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 176-181 
    Details
    ISSN: 1432-2145
    Keywords: Pollen ; Brassica napus ; Mitoses ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Brassica napus pollen development during the formation of the generative cell and sperm cells is analysed with light and electron microscopy. The generative cell is formed as a small lenticular cell attached to the intine, as a result of the unequal first mitosis. After detaching itself from the intine, the generative cell becomes spherical, and its wall morphology changes. Simultaneously, the vegetative nucleus enlarges, becomes euchromatic and forms a large nucleolus. In addition, the cytoplasm of the vegetative cell develops a complex ultrastructure that is characterized by an extensive RER organized in stacks, numerous dictyosomes and Golgi vesicles and a large quantity of lipid bodies. Microbodies, which are present at the mature stage, are not yet formed. The generative cell undergoes an equal division which results in two spindle-shaped sperm cells. This cell division occurs through the concerted action of cell constriction and cell plate formation. The two sperm cells remain enveloped within one continuous vegetative plasma membrane. One sperm cell becomes anchored onto the vegetative nucleus by a long extension enclosed within a deep invagination of the vegetative nucleus. Plastid inheritance appears to be strictly maternal since the sperm cells do not contain plastids; plastids are excluded from the generative cell even in the first mitosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190001
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  • 7
    Electronic Resource
    Electronic Resource
    Sperm cells of the pollen tubes of Brassica: Ultrastructure and isolation (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 226-234 
    Details
    ISSN: 1432-2145
    Keywords: Male germ unit ; Sperm cells ; Isolation ; Pollen tubes ; Brassica napus ; Pollen-tube inner plasma membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sperm cells of pollen tubes grown both in vivo and in vitro form a male germ unit. Extensions from both sperm cells of each pollen tube are closely associated with the tube nucleus. A high yield (2.7 × 104. 20 mg−1 pollen grains germinated) of intact sperm cells was obtained following release by osmotic shock from pollen tubes grown in vitro. Structural integrity of isolated sperm was maintained by isolation at low temperature in an osmotically balanced medium. At 4° C many isolated sperm pairs were still enclosed within the pollentube inner plasma membrane. Sperm cells not enclosed within this membrane no longer remained connected as a pair. During isolation vesicles formed on the sperm cell surface from disruption of the fibrillar components bridging the periplasmic space. Both in the pollen tube and after isolation the sperm nucleus is in close association with at least one region of the sperm plasma membrane. Sperm isolated at room temperature showed the presence of nucleopores, and nuclei were euchromatic, instead of heterochromatic as in intact sperm in the pollen tube.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190009
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  • 8
    Electronic Resource
    Electronic Resource
    Immunohistochemical characterization of HLA-DR-antigen positive dendritic cells in phaeochromocytomas and paragangliomas as a prognostic marker (1991)
    Springer
    Virchows Archiv 418 (1991), S. 33-39 
    Details
    ISSN: 1432-2307
    Keywords: HLA-DR ; Phaeochromocytomas ; Paragangliomas ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Twelve cases of phaeochromocytoma (PCC) and four cases of paraganglioma (PGG) were studied by immunohistochemistry and immunoelectron microscopy in order to demonstrate HLA-DR (Ia)-antigen-positive dendritic cells (IaDCs). Dense infiltration of IaDCs was detected in the majority of PCCs revealing high urinary or serum catecholamine levels, but in aggressively growing PCCs, a familial PCC and all PGGs, few IaDCs were demonstrated. Interestingly, these IaDCs were negative for S-100 protein. Although S-100-protein-positive sustentacular-like cells (SCs), morphologically similar to IaDCs, were also present, these were clearly distinguished from IaDCs by our double immunostaining method. Ultrastructurally, IaDCs had smooth or slightly indented nuclei and contained a moderate amount of endoplasmic reticulum, small mitochondria and vacuoles, extending elongated cytoplasmic processes. These results suggest that determination of the quantity of IaDCs is a highly effective method of assessing the character of PCCs, in particular, their prognosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600242
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  • 9
    Electronic Resource
    Electronic Resource
    Cell-mediated cytotoxicity in acute rat cardiac allograft rejection: An immunological and ultrastructural study (1991)
    Springer
    Virchows Archiv 418 (1991), S. 41-50 
    Details
    ISSN: 1432-2307
    Keywords: Cell-mediated cardiocyte injury ; Acute cardiac allograft rejection ; Mononuclear cellular infiltration ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To clarify the immune mechanism of cytotoxicity in acute cardiac allograft rejection, we observed interactions between cardiocytes and mononuclear cells using immunohistochemistry and light and electron microscopy. All allografted WKA rat hearts transplanted to F344 recipients stopped beating by the 7th day after the transplantation. The population of helper/inducer T cells (Th) and IL2R+ cells was large for the first 3 days, whereas that of cytotoxic/suppressor T cells (Tc-s) and macrophages increased from the 4th day. TheTh/Tc-s ratios were more than 2.0 until the 3rd day, then decreased to less than 1.0. In circulating T lymphocytes; theTh/Tc-s ratios were under 1.0 on the 1st, 6th and 7th days. Electron microscopically IL2R+ cells, Tc-s and macrophages were often seen in close contact with the plasma membrane of the cardiocytes. The majority of IL2R+ cells are NK cells, Tc-s andTh. Of these, the population of Tc-s was small until the 3rd day. Thus, NK cells play a pivotal role in the early stage of the rejection, and Tc-s and macrophages then aggravate cell-mediated cardiocyte injury.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600243
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  • 10
    Electronic Resource
    Electronic Resource
    The origin and abundances of the chemical elements revisited (1991)
    Springer
    The astronomy and astrophysics review 3 (1991), S. 1-46 
    Details
    ISSN: 1432-0754
    Keywords: Nucleosynthesis ; Nuclear reactions ; Stars: abundances ; Interstellar Medium: abundances ; Cosmology ; Galaxies: evolution of
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The basic scheme of nucleosynthesis (building of heavy elements from light ones) has held up very well since it was first proposed more than 30 years ago by E.M. Burbidge, G.R. Burbidge, A.G.W. Cameron, W.A. Fowler, and F. Hoyle. Significant advances in the intervening years include (a) observations of elemental and a few isotopic ratios in many more extrasolar-system sites, including metal-poor dwarf irregular galaxies, where very little has happened, and supernovae and their remnants, where a great deal has happened, (b) recognition of the early universe as good for making all the elements up to helium, (c) resolution of heavy element burning in stars into separate carbon, neon, oxygen, and silicon burning, with fine tuning of the resulting abundances by explosive nucleosynthesis in outgoing supernova shock waves, (d) clarification of the role of Type I supernovae, (e) concordance between elements produced in short-lived and long-lived stars with those that increased quickly and slowly over the history of the galaxy, and (f) calibration of calculations of the evolution and explosion of massive stars against the detailed observations of SN 1987A. The discussion presupposes a reader (a) with some prior knowledge of astronomy at the level of recognizing what is meant by an A star and an AGB star and (b) with at least a mild interest in how we got to where we currently are.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00873456
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  • 11
    Electronic Resource
    Electronic Resource
    Meningiomas differentiating to arachnoid trabecular cells: a proposal for histological subtype “arachnoid trabecular cell meningioma” (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 327-330 
    Details
    ISSN: 1432-0533
    Keywords: Meningioma ; Microcystic meningioma ; Vacuolated meningioma ; Arachnoid trabecular cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three cases of meningiomas which had abundant small vacuoles in the tumor tissue are reported. By electron microscopy, the tumor cells exhibited long and thin processes, the tips of which were united by desmosomes. The tumor tissue was revealed to have wide extracellular spaces which corresponded to the vacuoles observed by light microscopy. In previous literature, various terms have been used when referring to this meningioma, such as microcystic meningioma or vacuolated meningioma. Since the ultrastructure of the tumor showed similarity to that of normal arachnoid trabecular cells, we propose to call the tumor “arachnoid trabecular cell meningioma” denoting its morphological nature clearly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296542
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  • 12
    Electronic Resource
    Electronic Resource
    Histopathogenesis of inflammatory linear verrucose epidermal naevus: histochemistry, immunohistochemistry and ultrastructure (1991)
    Springer
    Archives of dermatological research 283 (1991), S. 491-499 
    Details
    ISSN: 1432-069X
    Keywords: Inflammatory linear epidermal naevus ; Keratinization ; DACM ; Involucrin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Skin lesions of three patients with inflammatory linear verrucose epidermal naevus (ILVEN) were examined. Histologically, orthokeratosis and parakeratosis were alternately seen in the acanthotic epidermis. By N-(7-dimethylamino-4-methyl-3-coumarinyl)maleimide staining, the horny cells in the parakeratotic epidermis showed a cytoplasmic SH pattern and a weak membranous SS pattern. The orthokeratotic epidermis revealed an increased involucrin expression, whereas the parakeratotic epidermis showed almost no involucrin expression. Ultrastructurally, in the parakeratotic epidermis, the living keratinocytes had prominent Golgi apparatuses and vesicles in the cytoplasm. In the intercellular spaces in the upper spinous layer through to the lower horny layer, an electron dense, homogeneous substance was deposited. The cytoplasm of the horny cells was filled with keratin filaments and contained remnants of nucleus and cytoplasmic membrane structures, and some lipid droplets. The marginal band formation was incomplete. Most of these ultrastructural abnormalities were not found in the orthokeratotic epidermis. There are both similarities and differences in histopathogenesis of the parakeratotic epidermis between ILVEN and psoriasis. A unique finding was the lack of involucrin expression in the ILVEN parakeratotic epidermis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371921
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  • 13
    Electronic Resource
    Electronic Resource
    The rhino mouse model: the effects of topically applied all-trans retinoic acid and CD271 on the fine structure of the epidermis and utricle wall of pseudocomedones (1991)
    Springer
    Archives of dermatological research 283 (1991), S. 100-107 
    Details
    ISSN: 1432-069X
    Keywords: Rhino mouse skin ; All-trans retinoic acid ; CD271 ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The histological and ultrastructural effects following 3 weeks' topical treatment with two agents (all-trans retinoic acid and a new synthetic retinoid-like substance, CD271) were evaluated on the epidermis and the epithelial wall of the pseudocomedones in rhino mouse skin. The comedolytic effects of these drugs were similar, and consisted of a reduction of the utricular diameter, with normalization of follicular units. Morphological examinations revealed a hyperplastic response with an increase in the number of cell layers of both epidermis and follicular epithelium, and modifications in keratinocyte differentiation. Ultrastructural changes in the epidermis and epithelial wall were observed mainly in the granular and horny layers, with increased desquamation, and a decrease in the cohesiveness of corneocytes. During the first week of treatment, some cutaneous toxic effects were noticed, but they normalized within two weeks. On the other hand, a fine granular material persisted in the intercellular spaces. It is confirmed that the skin of the rhino mouse is a good model for the evaluation of the comedolytic effects of drugs. Moreover, it reveals the specific effects of retinoids on epidermal differentiation. We have demonstrated that topically applied CD271 induces modifications similar to those obtained with all-trans retinoic acid. It is thus concluded that CD271 is a potentially effective anti-acne agent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371617
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  • 14
    Electronic Resource
    Electronic Resource
    Idiopathic prolactin cell hyperplasia of the pituitary mimicking prolactin cell adenoma: a morphological study including immunocytochemistry, electron microscopy, and in situ hybridization (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 147-151 
    Details
    ISSN: 1432-0533
    Keywords: Hyperplasia ; Pituitary ; Pathology ; Prolactin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Prolactin cell adenoma is the most frequently found lesion in surgically removed pituitaries of patients with hyperprolactinemia. However, in several instances, instead of prolactin cell adenoma, other lesions are encountered by morphological investigation. We report here the morphological findings in a patient with hyperprolactinemia who underwent transsphenoidal pituitary surgery for suspected prolactin cell adenoma. A morphological diagnosis of tumor could not be confirmed and massive diffuse prolactin cell hyperplasia was identified. The aim of this publication is to describe the lesion by histology, immunocytochemistry, electron microscopy, and in situ hybridization and to call attention to primary prolactin cell hyperplasia which can mimic prolactin cell adenoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293958
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  • 15
    Electronic Resource
    Electronic Resource
    Immunocytochemical and ultrastructural studies of hyaline inclusions in sporadic motor neuron disease (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 295-301 
    Details
    ISSN: 1432-0533
    Keywords: Hyaline inclusions ; Motor neuron disease ; Amyotrophic lateral sclerosis ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We investigated hyaline inclusion bodies (HI) immunocytochemically and ultrastructurally in six cases of sporadic motor neuron disease (MND). All HI contained large amounts of ubiquitin and some HI were stained at the core or the center with anti-neurofilament antibody, with the surrounding halo unstained. No HI were stained with antibodies raised against cytoskeletal proteins such as high-molecular weight microtubule-associated proteins and phosphorylated tau. Ultrastructurally, HI were chiefly composed of filaments measuring about 20 nm in diameter thicker than neurofilaments, and contained fine granules and frequently one or more of four characteristic profiles, i.e., small electron-dense materials resembling Bunina bodies, bundles of tubular filaments measuring approximately 20 nm in diameter, large electron-dense cores, and focal accumulations of randomly arranged neurofilaments. Hyaline inclusions can be regarded as one of the characteristic markers for sporadic MND as well as familial amyotrophic lateral sclerosis. Hyaline inclusions have a markedly heterogeneous ultrastructure and, therefore, differences in immunoreactivity with antineurofilament antibodies are not unexpected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308815
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  • 16
    Electronic Resource
    Electronic Resource
    Galactosialidosis: neuropathological findings in a case of the late-infantile type (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 331-339 
    Details
    ISSN: 1432-0533
    Keywords: Galactosialidosis ; Neuronal storage disease ; Neuropathology ; Ultrastructure ; Neuronal loss
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The neuropathological findings in a 13-year-old Japanese male showing decrease of sialidase and β-galactosidase activities are reported. The patient was the product of normal pregnancy to consanguineous parents. He started to sit at 8 months, stand at 20 months and walk at the age of 2; mental retardation, visual disturbance, cerebellar ataxia, myoclonus and epilepsy developed by the age of 10, and he died at 13. Neuropathological investigation revealed neuronal loss and storage. Severe loss of neurons was observed in the thalamus, globus pallidus, lateral geniculate body, gracile nucleus, Purkinje and retinal ganglion cells. Marked ballooning was seen in the Betz cells and neurons in the basal forebrain, the motor neurons in the cranial nerve nuclei and spinal cord, and in the trigeminal and spinal ganglia. The storage material varied in staining from region to region and from neuron to neuron. Electron microscopic investigation revealed a variety of intracytoplasmic and intranuclear inclusions: membranous cytoplasmic bodies, parallel, wavy-lamellar or tortuous tubular structures, lipofuscin-like irregular-shaped pleomorphic bodies, and cytoplasmic vacuoles with fine granules and lamellar materials. The severity of the neuronal loss did not seem to correlate with the amount of the storage materials, but with the presence of tortuous tubular inclusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296543
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  • 17
    Electronic Resource
    Electronic Resource
    Intramedullary secretory gangliocytoma (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 402-407 
    Details
    ISSN: 1432-0533
    Keywords: Gangliocytoma ; Ultrastructure ; Catecholamines ; Hypertension ; Spinal cord
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An 8-year-old boy developed severe systemic hypertension during resection of an intramedullary tumor. The histological, ultrastructural and immunocytochemical characteristics of the tumor are those of a gangliocytoma. Based on the demonstration of tyrosine hydroxylase in neuronal tumor cells, it is postulated that catecholamine secretion was responsible for the systemic hypertension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296552
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  • 18
    Electronic Resource
    Electronic Resource
    Fulminant blastomycosis with blastomycotic infection of a cerebral glioma (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 420-424 
    Details
    ISSN: 1432-0533
    Keywords: Blastomycosis ; North American Blastomy-cosis ; Brain tumor ; Opportunistic infection ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Except for isolated case reports, blastomycosis has not been identified as a significant problem in immunosuppressed patients. We describe an unusual case with blastomycotic infection of a cerebral glioma in a 56-year-old man who underwent radiotherapy for his tumor and died of fulminant blastomycotic pneumonia. This is believed to be the first reported case of Blastomyces dermatitidis infection of a cerebral glioma. The light microscopic and ultrastructural features of B. dermatitidis, the giant forms of which were encountered in our patient, are described, and the role of immuno-suppression due to steroid therapy in the pathogenesis of this fulminant infection are reviewed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296555
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  • 19
    Electronic Resource
    Electronic Resource
    Immunocytochemical and ultrastructural studies of Werdnig-Hoffmann disease (1991)
    Springer
    Acta neuropathologica 81 (1991), S. 408-417 
    Details
    ISSN: 1432-0533
    Keywords: Werdnig-Hoffmann disease ; Immunocytochemistry ; Ultrastructure ; Cytoskeleton ; Ubiquitin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuronal alterations in two cases of Werdnig-Hoffmann disease (WH) were investigated immunocytochemically and ultrastructurally. Ballooned neurons (BNs) were found in anterior horn, Clarke's column, dorsal root ganglion and thalamus. Anti-phosphorylated neurofilament antibodies preferentially stained the peripheral perikarya and proximal neuronal processes of BNs, whereas anti-ubiquitin antibodies preferentially stained the central perikarya of BNs. Ultrastructurally, BNs showed degenerative changes ranging from a diffuse increase of neurofilaments to a centrally accentuated accumulation of mitochondria and vesicular or membranous profiles. Our studies suggest that ubiquitinated degradation products accumulate in the center of the BN's perikaryon and displace aberrantly phosphorylated neurofilaments to the periphery. BNs in WH probably reflect an intrinsic alteration in the metabolism of neurofilaments that is associated with regressive changes in the neuron and eventually neuronal death.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293462
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  • 20
    Electronic Resource
    Electronic Resource
    The effect of denervation on the morphology of regenerating rat soleus muscles (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 21-32 
    Details
    ISSN: 1432-0533
    Keywords: Muscle ; Regeneration ; Denervation ; Ultrastructure ; Snake toxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study examines the level to which muscle regeneration proceeds in the absence of innervation. Regeneration was monitored in rat soleus muscles following localised injection of a snake toxin, notexin. Muscles which had been concomittantly denervated were compared with those that were normally innervated. Until 3–4 days following toxin administration regeneration is identical in both groups. The muscles contain new myotubes in place of the degenerated “parent” fibres. Thereafter, the non-denervated muscles grow rapidly and by 28 days their myofibres attain the size of those from the contralateral controls. Growth of denervated regenerating muscles, however, is retarded and is superseded by a gradual atrophy. In such muscles we further identify ultrastructural abnormalities from 7 days post-injection. These a re loss of individual myosin filaments and the presence of immature and abnormal configurations of the transverse system and triads. We, thus, conclude that innervation is an obligatory requirement for the restoration of normal myofibrillar and sarcotubular morphology, as well as growth, but is not necessary for the neo-formation of myofibres.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310919
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  • 21
    Electronic Resource
    Electronic Resource
    Bone marrow transplant in a case of mucopolysaccharidosis I Scheie phenotype: skin ultrastructure before and after transplantation (1991)
    Springer
    Acta neuropathologica 82 (1991), S. 33-38 
    Details
    ISSN: 1432-0533
    Keywords: MPS I-S ; Skin biopsy ; Ultrastructure ; Bone marrow transplant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An 11-year-old girl with mucopolysaccharidosis I Scheie phenotype (MPS I-S) received a bone marrow transplant (BMT) from her heterozygous HLA-identical LMC-non-reactive mother. Multidisciplinary studies were carried out and results evaluated 21 months after transplantation. Herein we report the ultrastructural findings pre-and post-BMT in skin. Multidisciplinary studies are commonly used to evaluate the benefits of metabolic correction following BMT in some MPS and other inherited metabolic disorders, and changes in morphology have been described in liver and few other tissues. In this case, we elected skin, since connective tissue is universally involved in MPS and is safely and easily obtainable. Comparison of skin biopsy specimens taken before and after BMT showed a considerable change in dermal fibroblast morphology, with marked reduction in cell size and the number and size of abnormal lysosomes, thus indicating the clearance of storage. Our results demonstrate that dermal cells respond to enzyme replacement therapy in MPS I-S, with the clearance of glycosaminoglycan lysosomal accumulation in connective tissue fibroblasts, which had near-normal morphology 21 months after BMT. Therefore, the practice of skin biopsy after BMT in MPS and other metabolic disorders in which dermal cells are involved should be encouraged.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310920
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  • 22
    Electronic Resource
    Electronic Resource
    Morphology of the synovium during its differentiation and development in the mouse knee joint (1991)
    Springer
    Anatomy and embryology 183 (1991), S. 537-544 
    Details
    ISSN: 1432-0568
    Keywords: Synovial membrane ; Development ; Ultrastructure ; Scanning electron microscopy ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The prenatal and postnatal development of the mouse knee joint was investigated by transmission and scanning electron microscopy. In the prenatal stage, following the appearance of a narrow intercellular cleft between two skeletal elements on the 16th fetal day, clefting extended into the lateral synovial mesenchyme. In some regions, the extension of the cleft was very rapid, but in a certain region (future fat pad region), it was somewhat slower. Macrophage-like cells appeared in the synovial mesenchyme on the 16th fetal day, and then increased in number, and were distributed as if they were clustering around the presumptive clefting zone in the future fat pad region on the 17th–18th fetal day. This suggests that macrophage-like cells may participate in joint development, as they phagocytize and remove some kinds of solid extracellular matrix, and facilitate the cleft extension. In the early postnatal stage, scanning electron microscopic observations showed that there were two different types of cell in the synovial lining. One of them exhibited a surface morphology corresponding to that of macrophages: a spherical cell body and numerous pseudopodia. The other type of cell exhibited various cell shapes with many cytoplasmic processes extending along the synovial surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00187902
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  • 23
    Electronic Resource
    Electronic Resource
    Scrapie inoculation of mice: light and electron microscopy of the superior colliculi (1991)
    Springer
    Acta neuropathologica 81 (1991), S. 562-571 
    Details
    ISSN: 1432-0533
    Keywords: Scrapie ; Ultrastructure ; Vacuolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural examination of the superior colliculi of mice intraocularly inoculated with the ME7 strain of scrapie showed vacuolation early in the course of infection. Brains were examined between 85–260 days after monocular inoculation with scrapie. The mean incubation period for the development of clinical disease was 302 days. Vacuolation was seen initially in the contralateral superior colliculus and subsequently in the ipsilateral colliculus. In coded trails light microscopical vacuolation was seen from 218 days but ultrastructural examination showed that sparse vacuoles were inconsistently present in either or both of the ipsilateral and contralateral colliculi from 85 days; frequent vacuoles were seen from 190 days. Scrapie-induced vacuoles were differentiated from vacuoles present in control tissue by the presence of loculation or by a limiting double membrane which showed protrusion or proliferation of the innermost lamella. Vacuolation was seen in neuronal perikarya, myelinated fibres, dendrites and axonal presynaptic terminals. Vacuoles of myelinated fibres were observed within myelin and possibly also in the inner tongue of oligodendroglial cytoplasm. Whorled membrane configurations were also seen. Tubulovesicular particles, 40 nm in diameter, were recognised in two scrapie-infected mice. It is suggested that some scrapie vacuoles arise as a result of incorporation of abnormal membrane into organelles, possibly mitochondria, in neuronal perikarya and neurites and probably also within oligodendroglial cytoplasm and myelin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310139
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  • 24
    Electronic Resource
    Electronic Resource
    Endothelial heterogeneity in the chick wing bud: A morphometric study (1991)
    Springer
    Anatomy and embryology 184 (1991), S. 47-53 
    Details
    ISSN: 1432-0568
    Keywords: Wing bud ; Endothelial cell ; Development ; Ultrastructure ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The microvascular endothelium of the chick wing bud at stages 22, 27, and 32 was evaluated by ultrastructural morphometry. The rationale for this study is based on the hypothesis that endothelial cells exhibit variation in structure and function during cytodifferentiation. The microvessels had a luminal diameter range such that they were classified as capillaries. The thin continuous endothelium was devoid of a basal lamina. The endothelium had a very small number of plasmalemmal vesicles; vacuoles were however present for all stages and in some cases were abundant. The temporal findings were that endothelial cell thickness increases, plasmalemmal vesicle densities decrease, and the densities of cytoplasmic vacuoles increase. The spatial results were that endothelial cells in proximal regions of the limb have a greater thickness, contain fewer vesicles and have more vacuoles than those in distal regions. In general, these results indicate that endothelial ultrastructural heterogeneity occurs within a 31/2 day timespan of wing bud development. The discussion considers the results with regard to recent reports on endothelial cell heterogeneity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01744260
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  • 25
    Electronic Resource
    Electronic Resource
    Development of taste organs inRana temporaria (1991)
    Springer
    Anatomy and embryology 184 (1991), S. 363-369 
    Details
    ISSN: 1432-0568
    Keywords: Taste organs ; Amphibia ; Development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In tadpoles ofRana temporaria two successive generations of taste organs: taste buds (TBs) and taste disks were studied. The TBs are located in the apices of oral premetamorphic papillae. Each TB consists of vertically elongated receptor cells (probably taste) and supporting cells. No basal (Merkel) cells were observed there. Morphologically, two types of receptor cells have been distinguished in a TB. Complete synaptic structures were observed in the TBs between the 30th and 41st of Gosner's (1960) developmental stages, though synaptic vesicles occur already at stage 26. The taste disks consist of taste cells, supporting cells and basal cells. Dense-core synaptic vesicles occur in the gustatory cells at stage 41, but complete synaptic structures were not observed earlier than at stage 45. Synaptic junctions observed at some of the gustatory cells seem to be reciprocal (bidirectional).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00957898
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  • 26
    Electronic Resource
    Electronic Resource
    The anatomy and fine structure of the echidnaTachyglossus aculeatus snout with respect to its different trigeminal sensory receptors including the electroreceptors (1991)
    Springer
    Anatomy and embryology 184 (1991), S. 371-393 
    Details
    ISSN: 1432-0568
    Keywords: Tachyglossus aculeatus (echidna) ; Echidna bill ; Sensory receptors ; Electroreceptor ; Mechanoreceptor ; Trigeminal nerve ; Monotreme ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The gross anatomy and nerve supply of the bill of echidna (Tachyglossus aculeatus) is described in relation to its function as an outstanding sensory organ. The sensory innervation of the skin of the echidna snout was investigated by means of frontal serial sections, after decalcification of the specimens. A comprehensive light and electron microscopic description of the location and fine structure of cutaneous sensory receptors of the trigeminal system was made by this means. The encapsulated and non-encapsulated Ruffini receptors, the types of other free receptors in the connective tissue and the Merkel cell receptor do not differ morphologically from those of higher mammals, whereas the pacinian-like corpuscle shows a unique organization of its outer core. This is composed of large perineural cells containing a unique reticulum of parallel-orientated endoplasmic membranes. Lamellated corpuscles, seen in isolation or in association with push rods, are numerous in the snout and in the tip of the tongue of echidna. Push rod receptor organs occur in the hairless skin of the bill with a very dense array at its rostral end and in the pseudopalatal ridges. Gland duct receptors are restricted to the skin adjacent to the nostrils and the mouth opening, including the pseudopalatal plates. Only about one quarter of the total number of 400 seromucous glands receive a sensory innervation of their intraepidermal duct segment. Within each innervated gland two types of receptor terminals are identified. The distributions of the different receptor types are mapped for different regions of the skin, the mucous membrane of the nasal and oral vestibule and the tip of the tongue. The fine structure of nerve terminals is discussed from a comparative anatomical point of view, and some speculations are made about possible transduction processes that underlie the known electrophysiological properties. The sensory organs such as the “push rod” and “gland duct receptor”, and most of their sensory terminals, are less differentiated in echidna snout than in the platypus (Ornithorhynchus anatinus) bill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00957899
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  • 27
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    Electronic Resource
    The origin of the nascent blastocoele in preimplantation mouse embryos ultrastructural cytochemistry and effect of chloroquine (1991)
    Springer
    Development genes and evolution 200 (1991), S. 77-85 
    Details
    ISSN: 1432-041X
    Keywords: Lysosomes ; Ultrastructure ; Chloroquine ; Blastocyst ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mouse morulae are known to undergo cavitation as soon as some external cells have entered the sixth cell cycle (Garbutt et al. 1987). Since the early cytological features of cavitation are still unclear, we undertook a careful ultrastructural analysis of late morulae-nascent blastocysts. In addition, since maturation of lysosomes might be involved in the first step of cavity formation, we focused our attention on these organelles by means of the cytochemical localization of trimetaphosphatase activity and by the study of the effects of chloroquine on precavitation embryos. Our results suggest that cavitation starts in a few external cells (presumably competent cells entering the sixth cell cycle), by the chloroquine-sensitive formation of degradative autophagic vacuoles engulfing lipid droplets and vacuoles containing osmiophilic material. These complex structures enlarge (as a result of lipid metabolism?) and so transform into intrablastomeric cavities which, by means of a membrane fusion process, very rapidly become extracellular cavities that coalesce. The abembryonic pole of the blastocyst is determined in this way. Moreover, we suggest that the juxtacoelic cytoplasmic processes covering the inner cell mass (ICM) cells, which are known to restrict the expression of their totipotency during early cavitation (Fleming et al. 1984), are the latest remnants of the walls of the growing intrablastomeric cavities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00637187
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  • 28
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    Electronic Resource
    Contributions of sodium and chloride to ultrastructural damage after dendrotomy (1991)
    Springer
    Experimental brain research 86 (1991), S. 60-72 
    Details
    ISSN: 1432-1106
    Keywords: Trauma ; Neuron ; Sodium ; Chloride ; Ultrastructure ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To determine the contributions of sodium and chloride to ultrastructural changes after mechanical injury, we amputated primary dendrites of cultured mouse spinal neurons in low calcium medium in which sodium chloride had been replaced with either choline chloride or sodium isethionate or sodium propionate. Uninjured cultured neurons were also exposed to the sodium ionophore, monensin. A third set of neurons was injured in medium in which all sodium and calcium chloride had been replaced with sucrose. Neurons injured in low-calcium, low-sodium medium exhibited few ultrastructural changes, except very near the lesion, where there was some dilation of mitochondria and cisternae of the smooth endoplasmic reticulum (SER). Mitochondria in other regions of the neurons developed an electron opaque matrix, and those nearer to the lesion converted to the condensed configuration, characterized by expanded intracristal spaces as well as a dense matrix. If sodium but not chloride was present in the medium, there was some dilation of the Golgi cisternae after injury, as well as some increased electron opacity of the mitochondria. Monensin treated neurons also exhibited dilation of the Golgi cisternae. Neurons injured in sucrose-substituted medium showed none of the changes associated with injury in normal culture medium. These results indicate that sodium influx through the lesion is involved in the dilation of the SER, which is seen even in low-calcium medium, and that a permeant anion, such as chloride, is also involved. This dilation of the SER may result from uptake of calcium released from mitochondria in response to elevated cytosolic sodium. Dilation of the Golgi cisternae appears to be a response only to elevated intracellular sodium. Condensation of the mitochondria after injury is thought to be due to increased demands for ATP synthesis and may involve a “futile cycling” of calcium across the mitochondrial membrane, involving sodium-mediated calcium release in response to elevated intracellular calcium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231040
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  • 29
    Electronic Resource
    Electronic Resource
    Ultrastructural study of the skin in Sjögren — Larsson syndrome (1991)
    Springer
    Archives of dermatological research 283 (1991), S. 141-148 
    Details
    ISSN: 1432-069X
    Keywords: Sjögren ; Larsson syndrome ; Ichthyosis ; Ultrastructure ; Lamellar body ; Keratinization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ichthyosiform skin and the uninvolved skin of a 5-year-old Japanese female with Sjögren — Larsson syndrome were examined by light and electron microscopy to elucidate the keratinization disorder. Light microscopically, the epidermis of the ichthyosiform skin showed acanthosis, papillomatosis and hyperkeratosis. The horny cells had a basket-weave appearance. The granular cell layer was slightly thickened. Slight round cell infiltration and vascular dilatation were seen in the upper dermis. The uninvolved skin was histologically normal. Electron microscopically, in both ichthyosiform and uninolved skin, abnormal lamellar or membranous inclusions were present in the cytoplasm of horny cells of the epidermis. These inclusions appeared to be derived from some of the lamellar bodies and/or abnormal membranous structures found in the cytoplasm of spinous and granular cells. Mitochondria in the epidermal basal cells were more numerous in the ichthyosiform skin than in the uninvolved skin. These findings indicate that, whether the skin is involved or not, the epidermis of the patient with this disorder may always have a structural abnormality, which may be genetically determined. Local environmental factors may play a role in inducing the acanthosis and papillomatosis of the epidermis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372053
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  • 30
    Electronic Resource
    Electronic Resource
    Are accessory nuclei involved in the establishment of developmental gradients in hymenopteran oocytes? (1991)
    Springer
    Development genes and evolution 199 (1991), S. 423-426 
    Details
    ISSN: 1432-041X
    Keywords: Oogenesis ; Accessory nuclei ; Developmental gradients ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the oocytes ofTenthredo olivacea, accessory nuclei (AN) are formed by budding from the nuclear envelope of the oocyte nucleus. Newly formed AN contain electron-dense material of nuclear origin and are surrounded by a double envelope devoid of pores. Such structures are subsequently transported to the peripheral ooplasm (periplasm), where they grow to reach a final diameter of 5 µm. In the envelopes of advanced AN nuclear pores arise. Through these pores “nuage” material is extruded into the surrounding periplasm. These findings are discussed with respect to a possible involvement of AN in the establishment of developmental gradients in hymenopteran oocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01705853
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  • 31
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    Electronic Resource
    Ultrastructure of the micropyle and its relationship to pollen tube growth and synergid degeneration in sunflower (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 166-175 
    Details
    ISSN: 1432-2145
    Keywords: Helianthus annuus ; Ultrastructure ; Micropyle ; Pollen tube ; Synergid degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ultrastructural studies made on the micropyle of sunflower before and after pollination resulted in the following observations. (1) The micropyle is closed instead of a hole or canal. The inner epidermis of the integument on both sides of the micropyle is in close contact at the apex of the ovule. The boundary between the two sides consists of two layers of epidermal cuticle. (2) The micropyle contains a transmitting tissue. The micropyle is composed of an intercellular matrix produced by the epidermal cells of the integument. (3) The micropyle is asymmetrical, and is much wider on the side proximal to the funicle. On the funicle side the cells adjacent to the micropyle are similar to those of the transmitting tissue: they have large amounts of intercellular matrix and contain abundant dictyosomes, rough ER, and starch grains, and provide an appropriate environment for growth of the pollen tubes. The cells distal to the funicle are rich in rough ER and lipid bodies; they lack large intercellular spaces. (4) The micropyle is variable in the axial direction, i.e., it is much larger and more asymmetric at the level distal to the embryo sac than at a level close to the embryo sac. After pollination, one to four pollen tubes are seen in a micropyle. During their passage through the micropyle, most pollen tubes are restricted to the side proximal to the funicle. There is a greater tendency (81%) for the degenerate synergid to be located toward the funicle, i.e., at the same side as the pollen tube pathway. The data indicate a close relationship between micropyle organization, orientation of pollen tube growth, and synergid degeneration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190000
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  • 32
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    Electronic Resource
    Microsporogenesis and tapetal development in fertile and cytoplasmic male-sterile sugar beet (Beta vulgaris L.) (1991)
    Springer
    Sexual plant reproduction 4 (1991), S. 215-225 
    Details
    ISSN: 1432-2145
    Keywords: Cytoplasmic male sterility ; Beta vulgaris ; Microsporogenesis ; Tapetum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of sporogenous and tapetal cells in the anthers of male-fertile and cytoplasmic male-sterile sugar beet (Beta vulgaris L.) plants was studied using light and transmission electron microscopy. In general, male-sterile anthers showed a much greater variability in developmental pattern than male-fertile anthers. The earliest deviation from normal anther development was observed to occur in sterile anthers at meiotic early prophase: there was a degeneration or irregular proliferation of the tapetal cells. Other early aberrant events were the occurrence of numerous small vesicles in the microspore mother cells (MMC) and a disorganized chromatin condensation. Deviations that occurred in sterile anthers at later developmental stages included: (1) less distinct inner structures in the mitochondria of both MMC and tapetal cells from middle prophase onwards. (2) dilated ER and nuclear membranes at MMC prophase, in some cases associated with the formation of protein bodies. (3) breakdown of cell walls in MMCs and tapetal cells at late meiotic prophase. (4) no massive increase in tapetal ER at the tetrad stage. (5) a general dissolution of membranes, first in the MMC, then in the tapetum. (6) abortion of microspores and the occurrence of a plasmodial tapetum in anthers reaching the microspore stage. (7) no distinct degeneration of tapetal cells after microspore formation. Thus, it seems that the factors that lead to abortive microsporogenesis are structurally expressed at widely different times during anther development. Aberrant patterns are not restricted to the tetrad stage but occur at early prophase.
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    URL: http://dx.doi.org/10.1007/BF00190008
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    Electronic Resource
    Varicocele in the rat: a new experimental model (1991)
    Springer
    Urological research 19 (1991), S. 319-322 
    Details
    ISSN: 1434-0879
    Keywords: Varicocele ; Rat, Histology ; Ultrastructure ; Temperature ; Infertility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary With no consistent animal prototype for the study of varicocele, we set out to create a model in the rat by complete ligation of the main branch of left spermatic vein (MBSV) or by partial ligation of the left renal vein. Three months later, the histology, ultrastructure and temperature of the testis and epididymis were studied. Microscopically, spermatogenic arrest was the most frequent anomaly seen. The most frequently noted ultrastructural change of the testis was distension of smooth endoplasmic reticula in Sertoli cells. The microvilli of columnar epithelia in epididymis were sparse and showed local defects. Lesions and increased temperatures in the testis and epididymis induced by the ligation of the left MBSV were similar to those seen in partial ligation of the left renal veins, with no significant differences between left and right. Significant differences were found, however, on comparison with the controls.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00299069
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  • 34
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    Electronic Resource
    Effect of 1,10-phenanthroline on ultrastructure of pea leaves (1991)
    Springer
    Protoplasma 161 (1991), S. 23-30 
    Details
    ISSN: 1615-6102
    Keywords: 1,10-Phenanthroline ; Photodynamic herbicides ; Pisum sativum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have examined ultrastructural changes of mesophyll cells in pea leaves induced by the photodynamic herbicide 1,10-phenanthroline (Phe). Dark incubation of pea plants did not cause any damage in plants or changes in the ultrastructure of mesophyll cells. Two hours of illumination after pretreatment with Phe caused photooxidative damage in plant but was not sufficient to markedly change the ultrastructure, although dilation of endoplasmic reticulum (ER) cisternae occurred. Illumination for 12 h caused inhibition of grana formation in pretreated plants. These ultrastructural changes and the inhibition of chlorophyll (Chl) accumulation may be due to the inhibition of transport of certain proteins to the plastids, diminished accumulation of chlorophyll proteins (e.g., LHCP) and a decrease in activity of the chlorophyll synthetase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01328894
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  • 35
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    Electronic Resource
    Intercellular permeability inAbutilon nectary trichomes (1991)
    Springer
    Protoplasma 161 (1991), S. 150-159 
    Details
    ISSN: 1615-6102
    Keywords: Abutilon ; Lucifer Yellow ; Microinjection ; Nectary ; Transport ; Trichome ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Intercellular transport was examined in nectary hairs ofAbutilon slriatum var.thompsonii using dye-uptake and microinjection followed by fluorescence and electron microscopy. Dye-uptake experiments demonstrated that both Lucifer Yellow CH (LYCH) and diaminobenzidine (DAB) move centrifugally along an apoplastic pathway from the sepellary tissue towards the tip cell. Further, fluorescence of LYCH could also be detected inside the cells of the nectary trichome. When LYCH or LYCH/DAB were microinjected into the tip cell, the dye spread in a centripetal direction towards the stalk cell. Electron microscopical investigations of microinjected nectary hairs revealed numerous electron-opaque globules in the cytoplasm of the nectary hair cells. In addition, multivesicular bodies, nuclei with opaque regions and changes in the rough endoplasmic reticulum (RER) were seen in nectary hair cells even at very low concentrations of injected dye. Ultrastructural investigations provided evidence for cytological changes in microinjected nectary hairs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01322727
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  • 36
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    Electronic Resource
    Ontogeny and ultrastructure of spontaneous nodules in alfalfa (Medicago sativa) (1991)
    Springer
    Protoplasma 162 (1991), S. 1-11 
    Details
    ISSN: 1615-6102
    Keywords: Rhizobium meliloti ; Development ; Symbiosis ; Nitrogen fixation ; Ultrastructure ; Spontaneous nodule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of spontaneous nodules, formed in the absence ofRhizobium and combined nitrogen, on alfalfa (Medicago sativa L. cv. Vernal) was investigated at the light and electron microscopic level and compared to that ofRhizobium-induced normal nodules. Spontaneous nodules were initiated from cortical cell divisions in the inner cortex next to the endodermis, i.e., the site of normal nodule development. These nodules, on uninoculated roots, were white multilobed structures, histologically composed of nodule meristems, cortex, endodermis, central zone and vascular strands. Nodules were devoid of intercellular or intracellular bacteria confirming microbiological tests. Early development of spontaneous nodules was initiated by series of anticlinal followed by periclinal divisions of dedifferentiated cells in the inner cortex of the root. These cells formed the nodular meristem from which the nodule developed. The cells in the nodule meristems divided unequally and differentiated into two distinct cell types, one larger type being filled with numerous membrane-bound starch grains, and the other smaller type with very few starch grains. There were no infection threads or bacteria in the spontaneous nodules at any stage of development. This size differentiation is suggestive of the different cell sizes seen inRhizobium-induced nodules, where the larger cell type harbours the invading bacteria and the smaller type is essential in supportive metabolic roles. The ontogenic studies further support the claim that these structures are nodules rather than aberrant lateral roots, and that plant possess all the genetic information needed to develop a nodule with distinct cell types. Our results suggest that bacteria and therefore theirnod genes are not necessarily involved in the ontogeny and morphogenesis of spontaneous and normal nodules in alfalfa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01403895
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  • 37
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    Effects of heat shock and thermoadaptation on the ultrastructure of cowpea (Vigna unguiculata) cells (1991)
    Springer
    Protoplasma 163 (1991), S. 125-135 
    Details
    ISSN: 1615-6102
    Keywords: Cowpea ; Heat shock ; Thermoadaptation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Suspension culture cells of cowpea (Vigna unguiculata) were examined using transmission electron microscopy to characterize morphological changes associated with hyperthermal stress. Cultures maintained at 26°C (unadapted cells) and 38°C (thermoadapted cells) were examined before and after exposure to elevated temperatures of 34°C and 45°C, respectively. Observations indicate that while there were significant ultrastructural differences between unadapted and thermoadapted cells, the following structural modifications in response to heat stress were observed in cells of both cultures: (a) almost a complete loss of polyribosomes, rough ER, and dictyosomes, (b) migration of intracellular waste material (presumably proteinaceous in composition) into the cell vacuole, (c) swelling of the nucleolus with assumed accumulation of preribosomal RNP granules, and (d) retraction of the tonoplast from the cytoplasm into the vacuoles of some cells. Heat shock granules (two size classes) were observed in the cytoplasm of stressed thermoadapted cells along with hollow-cored granules within the leucoplasts. Apart from a few minor differences, the morphological modifications that were made in apparent response to hyperthermal stress were remarkably similar in both cultures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01323336
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    Factor analysis in chemistry, (2nd edition), E. R. Malinowski, Wiley-Interscience, 1991. ISBN 0-471-53009-3. Price £43.70 (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 545-545 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050607
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    Recent developments in multivariate calibrationInvited Paper. (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 129-145 
    Details
    ISSN: 0886-9383
    Keywords: Multivariate calibration ; Biased regression ; Partial least squares (PLS) ; Principal component regression (PCR) ; Model validation ; Non-linear calibration ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: With the goal of understanding global chemical processes, environmental chemists have some of the most complex sample analysis problems. Multivariate calibration is a tool that can be applied successfully in many situations where traditional univariate analyses cannot. The purpose of this paper is to review multivariate calibration, with an emphasis being placed on the developments in recent years. The inverse and classical models are discussed briefly, with the main emphasis on the biased calibration methods. Principal component regression (PCR) and partial least squares (PLS) are discussed, along with methods for quantitative and qualitative validation of the calibration models. Non-linear PCR, non-linear PLS and locally weighted regression are presented as calibration methods for non-linear data. Finally, calibration techniques using a matrix of data per sample (second-order calibration) are discussed briefly.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050303
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    Real-time filtering of data from mobile, passive remote infrared sensors with principal component models of backgroundInvited Paper. (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 147-161 
    Details
    ISSN: 0886-9383
    Keywords: Digital filtering ; Real-time analysis ; Kalman filtering ; Infrared spectroscopy ; Principal components regression ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Real-time monitoring of pollutant levels from a mobile measuring platform requires fast, flexible data analysis methods. This paper reports a method for rapid analysis of passive remotely sensed infrared data with the aid of a Kalman filter. The background spectra produced by emission from the atmosphere are modelled at the start of the data collection sequence with a simple principal components model obtained by eigenanalysis of the initial ‘blank’ data taken with the spectrometer. The species of interest are included in the state space model by a separate measurement of their infrared spectra. It is demonstrated that for best filter performance in detecting the simulated pollutant species SF6 in the atmosphere, a filter model with two principal components describing the emission background works best. The filter ‘maps’ of SF6 closely follow the integrated spectral intensities measured after removal of suitable backgrounds.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050304
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    Examining large databases: A chemometric approach using principal component analysisInvited Paper. (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 163-179 
    Details
    ISSN: 0886-9383
    Keywords: Principal component analysis ; Factor analysis ; Chemometrics ; Exploratory data analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Principal component analysis is used to examine large multivariate databases. The graphical approach to exploratory data analysis is described and illustrated with a single example of chemical composition data obtained on environmental dust particles. While the graphical approach to exploratory data analysis has certain advantages over the numerical procedures, the empirical approach described here should be viewed as complementary to the more robust treatments that statistical methodologies afford.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050305
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  • 42
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    Experimental design in chemometricsInvited Paper. (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 181-192 
    Details
    ISSN: 0886-9383
    Keywords: Chemometrics ; Systems theory ; Experimental design ; Multivariate analysis ; Measurement science ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemometrics is defined as the application of mathematical and statistical methods to chemical systems. Systems theory is seen to be useful for organizing and categorizing the inputs to and outputs from chemical systems. Advances in measurement science in the 1950s and 1960s, particularly in analytical chemistry, created a need for a multivariate approach to data analysis. Early chemometrics emphasized the use of structure-finding methods for existing data sets. In many instances, data sets can be obtained from designed experiments. Such data sets are more likely to contain the desired information and the data can usually be acquired at less cost. Renewed interest in statistical process control will provide many new, more robust data sets in the future.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050306
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  • 43
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    Simultaneous analysis of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) by spectrophotometry and the Kalman filter (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 193-199 
    Details
    ISSN: 0886-9383
    Keywords: Kalman filter ; Chemometrics ; 5-Br-PADAP ; Metallic ions ; Simultaneous spectrophotometric determination ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper describes the simultaneous determination of cobalt, nickel, copper, zinc and cadmium by spectrophotometry and the Kalman filter method. Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) react with 5-bromo-2-(2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) in the presence of cationic surfactant cetyl pyridinium bromide (CPB) to form five different coloured ternary complexes. The absorption curves of these complexes overlap severely in the scanning range 500-620 nm. The Kalman filter algorithm is successfully applied to resolve the overlapped absorption curves and therefore makes the simultaneous determination of these metallic ions possible without tedious pretreatment. The proposed method is applied to analyse the titled elements in synthetic samples and in environmental samples such as hair, fingernail and river water samples with satisfactory results.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050307
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  • 44
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    Step function technique for estimating data uncertainty in experimental results (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 201-209 
    Details
    ISSN: 0886-9383
    Keywords: Uncertainty ; Step function ; Additive model ; Transformation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An additive model is used to express the observed value of a sample characteristic as the sum of the true sample characteristic and a value of the data collection error, commonly known as experimental error. The data uncertainty of the experimental results (or of a survey data set) is defined as the expected squared error. The expected squarred error may change with the sample characteristic, e.g. the error moment could be concentration-dependent. The relationship between the error variance and the analyte concentration may not be very distinct. In such a case the data transformation to stabilize the error moments may not be appropriate. A step function is proposed as an alternative way to represent the second moment of the error. The data uncertainty is defined as the weighted average of the step values of the second raw moment of the error, using the appropriate proportions of the routine samples as weights. The data uncertainties associated with the different data collection stages were evaluated by using regional soil survey data.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050308
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  • 45
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    Expectation-maximization algorithm for regression, deconvolution and smoothing of shot-noise limited data (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 211-225 
    Details
    ISSN: 0886-9383
    Keywords: Shot noise ; Expectation-maximization ; Regression ; Deconvolution ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple algorithm for deconvolution and regression of shot-noise-limited data is illustrated in this paper. The algorithm is easily adapted to almost any model and converges to the global optimum. Multiple-component spectrum regression, spectrum deconvolution and smoothing examples are used to illustrate the algorithm. The algorithm and a method for determining uncertainties in the parameters based on the Fisher information matrix are given and illustrated with three examples. An experimental example of spectrograph grating order compensation of a diode array solar spectroradiometer is given to illustrate the use of this technique in environmental analysis. The major advantages of the EM algorithm are found to be its stability, simplicity, conservation of data magnitude and guaranteed convergence.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050309
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    Estimation of errors in absorbance ratio measurements (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 291-298 
    Details
    ISSN: 0886-9383
    Keywords: Absorbance ratio ; Statistical confidence ; Quality control ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ratio measurements are commonly used to address a variety of analytical problems in environmental, forensic and pharmaceutical laboratories. In absorbance ratioing techniques, analytical chemists rely on the spectral features of the analyte(s) of interest. The absorbances at two wavelengths are monitored and the ratio of these two absorbances is computed. This ratio is then used to confirm the identity of the analyte(s) of interest, the purity of a product of the overlap of chromatographic peaks. These decisions often have far-reaching consequences (e.g. the identification of the source, biogenic or petrogenic, of hydrocarbons in biological tissues or water). Given the cost and the liabilities associated with such decisions, it is unfortunate that these ratios are seldom reported with any statistical confidence. The purpose of this study is to delineate the parameters that affect absorbance ratio measurements. The models that can be used to estimate the statistical confidence in these measurements are derived and evaluated experimentally. The results show that these models can estimate the relative standard deviations in absorbance ratios accurately. They can also estimate the effect of signal-to-noise ratio and the choice of wavelengths on the precision of absorbance ratios.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050315
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    Likelihood techniques for interlaboratory calibration in the national stream survey (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 299-308 
    Details
    ISSN: 0886-9383
    Keywords: Errors in variables ; Orthogonal regression ; Latent variables ; Acid rain ; Acidic deposition ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Techniques for testing for and estimating relative bias between two laboratories are developed and applied to a survey of the chemistry of streams in the United States. The design of the quality assurance program allows estimation of linear corrections for bias as well as testing of the hypothesis of linearity. Designs of this type are useful, but improvements are suggested.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050316
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    On confidence intervals for the product of three means of three normally distributed populations (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 309-319 
    Details
    ISSN: 0886-9383
    Keywords: Confidence intervals ; Products of normal random variables ; Risk/exposure modeling ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In many environmental applications, such as exposure assessment and risk modelling, the desired estimate is a random variable computed as the product of three independently distributed random variables. These variables may not necessarily have the same mean and variance. The method for finding the 100(1 - α)% confidence interval for the mean of the product random variable has been proposed by some practitioners as the product of the 100(1 - α)% confidence interval of the three means. In this paper we show that the distribution of the product of three independent normal variables is not normal. We find the mean and variance of the product distribution. Further, we show that although the mean of the product is equal to the product of the means, the product of the three confidence intervals is not a good approximation of the confidence intervals for the mean of the product variable. The confidence interval of the mean of the product variable may be estimated by computer simulation. An algorithm for estimating the confidence interval for the mean of the product random variable is given. The program implementing this algorithm is given as an appendix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050317
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    Comparison of two screening methods for the detection of volatile organic compounds in ground water (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 321-331 
    Details
    ISSN: 0886-9383
    Keywords: Screening ; Ground-water quality ; Monitoring ; Volatile organic compounds (VOCs) ; Optimization ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that the presence of 31-35 commonly measured volatile organic compounds (VOCs) in ground water can be detected with small error rates by using screening methods which analyze for a subset of such VOCs. A study of selected data sets indicates that analytical determinations of only from two to eight VOCs will suffice to detect 95% of all VOC hits. It is also shown that a serially optimal algorithm for selecting the VOCs for screening is very nearly as accurate as a globally optimal algorithm and much easier to implement. These conclusions are supported by empirical evidence from two drinking-water data sets and one hazardous waste site data set. Additional research areas are also outlined.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050318
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    Masthead (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991) 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050401
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    Diary (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. i 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050402
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    A bootstrap resampling scheme for using the canonical correlation technique in rank estimation (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 333-343 
    Details
    ISSN: 0886-9383
    Keywords: Rank estimation ; Bootstrap resampling ; Canonical correlation ; Excitation-emission matrix ; Singular value decomposition ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rank estimation by canonical correlation analysis in multivariate statistics has been proposed as an alternative approach for estimating the number of components in a multicomponent mixture. A methodological turning point of this new approach is that it focuses on the difference in structure rather than in magnitude in characterizing the difference between the signal and the noise. This structural difference is quantified through the analysis of canonical correlation, which is a well-established data reduction technique in multivariate statistics. Unfortunately, there is a price to be paid for having this structural difference: at least two replicate data matrices are needed to carry out the analysis.In this paper we continue to explore the potential and to extend the scope of the canonical correlation technique. In particular, we propose a bootstrap resampling method which makes it possible to perform the canonical correlation analysis on a single data matrix. Since a robust estimator is introduced to make inference about the rank, the procedure may be applied to a wide range of data without any restriction on the noise distribution. Results from real as well as simulated mixture samples indicate that when used in conjunction with this resampling method, canonical correlation analysis of a single data matrix is equally efficient as of replicate data matrices.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050403
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    Three-way methods for the calibration of chromatographic systems: Comparing PARAFAC and three-way PLS (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 345-360 
    Details
    ISSN: 0886-9383
    Keywords: Three-way PCA ; Three-way PLS ; PARAFAC ; Trilinear ; Unfolding ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For the calibration of chromatographic systems, different methods can be used. One class of methods utilizes three-way approaches. The calibration problem is stated in such a way that the decomposition of a three-way array can serve for the prediction of retention on new stationary phases.Two three-way approaches are presented: the Unfold-PCA and PARAFAC models. The theory of both methods is presented and the differences are highlighted, the main difference being that PARAFAC is a trilinear decomposition whereas Unfold-PCA is not. Both three-way methods are evaluated on a small data set consisting of retention measurements of eight solutes at six mobile phase compositions on six stationary phases. The differences in performance of the two models are minor.For calibration purposes, two variants of the methods are discussed: three-way PLS and an extension of PARAFAC. Again the theory and differences between the two methods are explained. The predictive performance of the two methods is compared using the same data set as earlier. The differences in predictive performance, however, are minor. Both methods are capable of predicting 98% of the variation in the test sets. Yet, there are other considerations when comparing methods than predictive performance, e.g. the quality of the predictions.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050404
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    Estimation in compositional data analysis (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 361-374 
    Details
    ISSN: 0886-9383
    Keywords: Closure ; Normalization ; Multivariate trimming ; Minimum distance ; Bootstrap ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Compositional data arise naturally in several branches of science, including chemistry, geology, biology, medicine, ecology and manufacturing design. In chemistry, these constrained data seem to occur typically when raw data are normalized or when output is obtained from a constrained estimation procedure, such as might be used in a source apportionment problem. It is important not only for chemists to be aware that the usual multivariate statistical techniques are not applicable to constrained data, but also to have access to appropriate techniques as they become available. The currently available methodology is due principally to Aitchison and is based on log-normal models. This paper suggests new parametric and non-parametric approaches to significantly improve the existing methodology. In the parametric setting, some recent work of Rayens and Srinivasan is extended and a practical regression model is proposed. In the development of the non-parametric approach, minimum distance methods coupled with multivariate bootstrap techniques are used to obtain point and region estimators.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050405
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    A test of three fitting criteria for multiresponse non-linear modeling (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 375-387 
    Details
    ISSN: 0886-9383
    Keywords: Determinant criterion ; Multiresponse non-linear fitting ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This work evaluates objective functions for multiresponse non-linear modeling using computer simulations. Tests are performed under a variety of signal-to-noise ratios and noise variance-covariance structures. The standard error of prediction for the model parameters, computed from 50 trials, is used for performance comparisons. The full rank and rank-deficient problems are considered. For the full rank problem one model was investigated, a first-order two-step consecutive reaction model, and two objective functions were considered, the total sum of squares and the determinant criterion. No distinction could be made between the two objective functions for this model.For the rank-deficient case two models were investigated, a first-order two-step consecutive reaction as in the full rank case, and a pH titration model described by the Henderson-Hasselbalch equation. Three objective functions were investigated for the rank-deficient case, the total sum of squares, a weighted total sum of squares and the determinant criterion. The total sum of squares was found to perform poorly under all conditions tested compared to the weighted total sum of squares and the determinant criterion. The determinant criterion was found to perform much better than the other two criteria when the data have a combination of a low signal-to-noise ratio and high variance-covariance noise structure.
    Additional Material: 7 Tab.
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    URL: http://dx.doi.org/10.1002/cem.1180050406
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    The chemometrics team of MITAC (Micro and Trace Analysis Center), University of Antwerp, Belgium (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 405-409 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050408
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    Comparison of pattern recognition descriptors for chemical acoustic emission analysis (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 389-403 
    Details
    ISSN: 0886-9383
    Keywords: Acoustic emission ; Pattern recognition ; Feature selection ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Features used to characterize acoustic emission signals from chemical systems are evaluated with regard to their potential for pattern recognition. Eight chemical systems involving phase transitions, hydration, dissolution and effervescence are employed and treated as separate signal classes. These are compared pairwise and the discriminatory capabilities of about 50 features are investigated by computing Fisher weights. Time domain and frequency domain descriptors are examined. Correlations among the features evaluated are also reported. Recommended descriptors are the mean and median frequencies, frequency bandwidth, number of level crossings (0% and 25%), crest factor (time and frequency domains), half-life, kurtosis and normalized percentiles of the signal and its power spectrum. The effectiveness of the recommended descriptors is demonstrated through the separation of signal classes in two different systems (melting ice and an enzyme-catalyzed gas formation reaction) by principal components analysis.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cem.1180050407
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    Scientific computing and automation (Europe) 1990 (Proceedings of the Scientific Computing and Automation (Europe) Conference, 12-15 June 1990, Maastricht, The Netherlands), edited by E. J. Karjalainen for the series Data Handling in Science and Technology, 6, Elsevier Science Publishers, Amsterdam, 1990, 514 pp., ISBN 0-444-88949-3, US$220.00/Dfl. 385.00 (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 411-412 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050409
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    UNSCRAMBLER 11, version 3.10: A program for multivariate analysis with PLS and PCA/PCR. Available from CAMO AS, Jarlevn. 4, Trondheim, Norway. Price $3000; academic discount price $1500 (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 413-415 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050410
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    Announcement (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 416-416 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050411
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    Masthead (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991) 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050501
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  • 62
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    Diary (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. i 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050502
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  • 63
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    Rapid estimation of the number of coeluting components in liquid chromatography by factor analysis (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 417-434 
    Details
    ISSN: 0886-9383
    Keywords: Factor analysis ; Power density distribution ; Chromatography ; Absorption spectroscopy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Evaluation of the results of factor analysis of sets of spectroscopically detected chromatograms is carried out by examining the shapes of the abstract factors. This is done either by visual inspection or by analysis of the power density spectra produced from them. Owing to constraints imposed by the column function and the spectroscopic instrument function, the information content of the chromatograms necessarily occurs at low spatial frequencies. As a consequence, it appears as relatively broad features in the abstract chromatograms and as a peak in the low-frequency region of the corresponding power density plot. On the basis of examination of the power density distribution, a well-defined distinction is made between primary and secondary abstract factors. The major uncertainty encountered in determining the number of chemical components appears to arise from effects of contaminants in reagents.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050503
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    A class-modelling technique based on potential functions (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 435-453 
    Details
    ISSN: 0886-9383
    Keywords: Class-modelling methods ; Potential functions ; Pattern recognition ; Discriminant analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A probabilistic and distribution-free class-modelling technique is developed from potential function discriminant analysis. In the multidimensional space of variables the class boundary is built either by the sample percentile of the probability density estimated by means of potential functions, or by the estimate of the ‘equivalent’ determinant of the variance-covariance matrix. The equivalent determinant is that of a hypothetical multivariate normal distribution whose mean probability density was obtained by potential functions. The bases of this modelling rule are evaluated by means of Monte Carlo experiments. The results on four datasets are used to measure the performances of this method, which equal and sometimes exceed the performances of parametric class-modelling methods based on linear and quadratic discriminant analysis which were used for comparison.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050504
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  • 65
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    Correspondence analysis and adsorbate selection for chemical sensor arrays (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 455-465 
    Details
    ISSN: 0886-9383
    Keywords: Correspondence analysis ; Cluster analysis ; Optimization ; Eigenanalysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carey et al. utilized principal components analysis (PCA) to analyze frequency shift data obtained from piezoelectric sensors formed by coating quartz crystals with 27 different GC stationary phases and tested using 14 analytes. The objective of the analysis was to determine an optimal reduced set of coatings for detection of the analytes. The results were correlated with those obtained from cluster analysis. In this paper the data are re-analyzed using correspondence analysis (CA). The advantage of using CA include a symmetric treatment of sensor coatings and analytes and better identification of the representation of the analytes in terms of the detection components. The results obtained by the conjunctive use of PCA, a varimax rotation and cluster analysis were obtained by CA.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050505
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  • 66
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    Fuzzy multivariate rule-building expert systems: Minimal neural networks (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 467-486 
    Details
    ISSN: 0886-9383
    Keywords: Expert system ; Neural network ; Fuzzy entropy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A fuzzy multivariate rule-building expert system (FuRES) has been devised which also functions as a minimal neural network. This system builds rules from training sets of data that use feature transformation in their antecedents. The rules are constructed using the ID3 algorithm with a fuzzy expression of classification entropy. The rules are optimal with respect to fuzziness and can accommodate overlapped and underlapped clusters of data. The FuRES algorithm combines the benefits obtained from simulated annealing and gradient optimization, which provide robustness and efficiency respectively. FuRES classification trees support OR logic in their inference. The system automatically generates meaningful and consistent certainty factors during rule construction. Unlike other neural networks, FuRES uses local processing which furnishes qualitative information in the rule structure of its classification trees and variable loadings of the weight vectors.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050506
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  • 67
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    Masthead (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991) 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050601
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  • 68
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    Diary (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. i 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050602
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  • 69
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    Multivariate calibration when data are split into subsets (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 487-501 
    Details
    ISSN: 0886-9383
    Keywords: Calibration ; Locally linear models ; Discrimination ; Optimality ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A calibration situation is considered where the calibration data are split into subsets with good linear relationship between y and x within each group. Different strategies for good prediction in this case are proposed. Modifications for collinear data are considered and a simple simulated data set is used for illustration.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050603
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  • 70
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    Rank-order analysis for robust multiresponse, multiblock comparisons: Evaluation of herbicide interactions (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 503-521 
    Details
    ISSN: 0886-9383
    Keywords: Antagonism ; Bounded ordinal scale ; Herbicide interaction ; Inter block comparisons ; Non-parametric ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies of interactions among bioactive compounds are often difficult to interpret unambiguously. A priori assumptions about the nature of such interactions can seriously distort analysis of the data. By applying a rank order analysis appropriate to the naturally ordinal scale of response to xenobiotic insult, several co-herbicides were successfully identified from among numerous candidates in an experiment involving multiple blocks, rates and species. Moreover, underlying herbicide interactions were substantiated and identified which were not apparent by more traditional parametric analysis.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050604
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  • 71
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    Diary (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. i 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050102
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  • 72
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    Tutorial to robust statistics (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 1-20 
    Details
    ISSN: 0886-9383
    Keywords: Averaging ; Median ; Outliers ; Regression ; Residuals ; Robustness ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this tutorial we first illustrate the effect of outliers on classical statistics such as the sample average. This motivates the use of robust techniques. For univariate data the sample median is a robust estimator of location, and the dispersion can also be estimated robustly. The resulting ‘z-scores’ are well suited to detect outliers. The sample median can be generalized to very large data sets, which is useful for robust ‘averaging’ of curves or images. For multivariate data a robust regression procedure is described. Its standardized residuals allow us to identify the outliers. Finally, a survey of related approaches is given. (This review overlaps with earlier work by the same author, which appeared elsewhere.)
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050103
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  • 73
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    Use of the Wronskian determinant in the study of multicomponent systems (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 21-35 
    Details
    ISSN: 0886-9383
    Keywords: Wronskian determinant ; Multicomponent systems ; Derivative spectroscopy ; Spline functions ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of Wronskian determinants in the study of multicomponent systems is proposed. The general theory is presented and applied to the spectrophotometric determination of the number of linearly independent components-absorbers. A detailed study of a two-component system is presented and analysed. Numerical methods for smoothing and differentiation of digitized spectra via cubic splines are used.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050104
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  • 74
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    Splitting of calibration data by cluster analysis (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 49-65 
    Details
    ISSN: 0886-9383
    Keywords: Calibration ; Cluster analysis ; Local linearity ; Mahalanobis distance ; Residual distance ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The topic of the present paper is the splitting of calibration data into subgroups with improved linearity in each group. The method proposed is based on a criterion which is a weighted average of a Mahalanobis distance and a squared regression residual. The algorithm used to find the solution is based on fuzzy clustering. Two examples are given to illustrate the theory.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050106
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  • 75
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    Generalized simulated annealing for calibration sample selection from an existing set and orthogonalization of undesigned experiments (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 37-48 
    Details
    ISSN: 0886-9383
    Keywords: Optimization ; Simulated annealing ; Calibration ; Experimental design ; Multicomponent analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Generalized simulated annealing (GSA) is an optimization procedure for locating the global optimum (maximum or minimum) of multidimenisonal continuous functions. GSA has been modified for optimization of discrete functions. Selection of calibration samples from an existing set defines discrete optimization and GSA is used to select optimal sets of calibration samples for specific analysis samples. The procedure is applied to near-infrared spectra. When compared to using the complete set of 37 calibration samples, concentration prediction errors were reduced 50%-100% by using select sets of two to seven calibration samples. Additionally, GSA was able to improve a poorly designed experiment. GSA devised augmented experimental designs such that the overall experimental design (original plus augmented) was more orthogonal than the original.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050105
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    Computational methods in the chemical sciences, A. F. Carley and P. H. Morgan, Ellis Horwood, Ltd, Chichester, U.K., 1989. ISBN 0-85312-746-8 (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 68-69 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050108
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    Computerized multiple input chromatography, M. Kaljurand and E. Küllik, Ellis Horwood, Chichester, U.K., 1989. No. of pages: 225. ISBN 0-7458-0120-X. Price £45.00 (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 67-67 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050107
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  • 78
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    Editorial (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 71-71 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050203
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  • 79
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    The use of a ratio method as an alternative to constrained deconvolution (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 85-95 
    Details
    ISSN: 0886-9383
    Keywords: Deconvolution ; Gold's ratio ; Iterative deconvolution ; Chromatographic deconvolution ; Peak restoration ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper will consider the use of an iterative ratio technique called Gold's ratio method as an alternative to iterative constrained deconvolution methods for the restoration of overlapped and noisy chromatograpic peaks. The study will consist of first describing the technique and then evaluating its performance with respect to Jansson's deconvolution procedure. A Hewlett-Packard 5890A gas chromatograph will be used to generate most of the test data. The evaluation criteria will include convergence rates, peak area errors and variances, retention time variances and noise performance.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050205
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  • 80
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    Comparison of measurement methods based on a model for the error structure (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 523-536 
    Details
    ISSN: 0886-9383
    Keywords: Measurement errors ; Method comparison ; Mean square successive difference ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Comparison of methods is a technique often used for investigation of systematic errors of measurement methods. As concerns the design and analysis of such comparisons, much variety of opinion and practice exists. In one approach a few specimens are measured several times by different operators in different laboratories (reproducibility conditions) and in another approach several specimens are measured on one or a few occasions by one operator in the same laboratory (repeatability conditions). In this paper a model for the error structure of measurements is formulated and it is emphasized that one has to distinguish between two types of systematic errors: the first type depends only on the level of the measured quantity and the second type is specific for the separate specimens. On the basis of this model the information which can be obtained from the different designs of method comparisons is discussed. A new approach for the analysis of method comparisons with many specimens is also proposed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050605
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    Announcement (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 69-69 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050109
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    Some issues in chemometrics with environmental applications (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 121-128 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050302
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    Laboratorio di Chemiometria, University of Perugia, Italy (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 537-543 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050606
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    Diagnostika Sostava Materialov Rentgenodifrakcionnimi I Spektralnymi Metodami (Identification of materials by X-ray diffraction and spectroscopical Techniques) (in Russian), M. S. Nakhmanson and V. G. Feklitschev, Mashinostroenie, Leningrad, 1990. 357 pages. ISBN 5-217-00915-2, Rubl 5.40 (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 546-547 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050608
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    Masthead (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991) 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050101
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  • 86
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    Masthead (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991) 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050201
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  • 87
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    Diary (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. i 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050202
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  • 88
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    A new serial method for searching the optimum operating conditions of a technological process (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 73-84 
    Details
    ISSN: 0886-9383
    Keywords: Optimization ; Technological process ; COMPLEX algorithm ; ANTICOMPLEX algorithm ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new program, named ANTICOMPLEX, has been specially written for searching the optimum conditions of a technological process. The algorithm is based on an iterative procedure with, at each step, a random sampling for a better exploration of the hyperspace of the parameters. Since the process is considered as a ‘black box’, the program operates by successive reductions of the variation domains with a strategy derived from some function optimization (COMPLEX). This approach is very flexible and the experimenter can stop the investigation at any series of experiments according to the desired accuracy for the optimum region. This program has been successfully tested on several real processes. This paper gives a complete description of the approach together with two illustrations on simulated processes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050204
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    The Laboratory for Chemometrics, University of Washington, Seattle (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 113-116 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050207
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  • 90
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    Announcements (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 117-119 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050208
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  • 91
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    Regression on multivariate images: Principal component regression for modeling, prediction and visual diagnostic tools (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 97-111 
    Details
    ISSN: 0886-9383
    Keywords: Multivariate images ; Principal component regression ; Multivariate image regression ; Regression model ; Predicted image(s) ; Prediction quality scatter plot ; Visual diagnostic tools ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Regression between two blocks (usually called ‘dependent’ or Y and ‘independent’ or X) of data is a very important scientific and data-analytical tool. Regression on multivariate images is possible and constitutes a meaningful addition to existing univariate and multivariate techniques of image analysis. The regression can be used as a modeling tool or for prediction. The form of the regression equation chosen is dependent upon problem specification and information at hand. This paper describes the use of principal component regression (PCR). Both model building and prediction are presented for continuous Y-variables. The final goal is to supply new image material that can be used for visual inspection on a screen. Also, visual tools for diagnosis of model and prediction are provided, often based on derived image material. Examples of modeling and prediction are given for six channels in a seven-channel satellite image.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050206
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  • 92
    Electronic Resource
    Electronic Resource
    Masthead (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991) 
    Details
    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
    URL: http://dx.doi.org/10.1002/cem.1180050301
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  • 93
    Electronic Resource
    Electronic Resource
    Box-Cox transformations in the analysis of compositional data (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 227-239 
    Details
    ISSN: 0886-9383
    Keywords: Unit-sum constraint ; Mixing proportions ; Ratio data ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The statistical analysis of compositional data is of fundamental importance to practitioners in general and to chemists in particular. The existing methodology is principally due to Aitchison, who effectively uses two transformations, a ratio followed by the logarithmic, to create a useful, coherent theory that in principle allows the plethora of normal-based multivariate techniques to be used on the transformed data. This paper suggests that the well-known class of Box-Cox transformations can be employed in place of the logarithmic to significantly improve the existing methodology. This is supported in part by showing that one of the most basic problems that Aitchison managed to overcome, namely the specification of an interpretable covariance structure for compositional data, can be resolved, or nearly resolved, once the ratio transformation has been applied. Hence the resolution is not directly dependent on the logarithmic transformation. It is then verified that access to the general Box-Cox family will allow a more accurate use of the normal-based multivariate techniques, simply because better fits to normality can be achieved. Finally, maximum likelihood estimation and some associated asymptotics are employed to construct confidence intervals for ratios of the true, unknown compositional constituents. Heretofore this had not been done even in the context of the logarithmic transformation. Applications to real data are presented.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050310
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  • 94
    Electronic Resource
    Electronic Resource
    Finding causes of outliers in multivariate environmental data (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 241-248 
    Details
    ISSN: 0886-9383
    Keywords: Multivariate kurtosis ; Generalized distance ; Multivariate outliers ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multivariate outliers in environmental data sets are often caused by atypical measurement error in a single variable. From a quality assurance perspective it is important to identify these variables efficiently so that corrective actions may be performed. We demonstrate a procedure for using two multivariate tests to identify which variable ‘caused’ each outlier. The procedure is tested with simulated data sets have have the same correlation structure as selected water chemistry variables from a survey of lakes in the Western United States. The success rates are evaluated for three of the variables for sample sizes of 50 and 100, significance levels of 0.01 and 0.05 and various amounts of mean shift. The procedure works best for highly correlated variables.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050311
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  • 95
    Electronic Resource
    Electronic Resource
    A statistical procedure to evaluate clean-up standards (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 249-261 
    Details
    ISSN: 0886-9383
    Keywords: Asymptotic power ; Clean-up standard ; Gamma distribution ; Likelihood ratio test ; Uniformly most powerful unbiased test ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The object of this paper is to develop a suitable statistical procedure to evaluate clean-up standards at hazardous waste sites. Under the assumptions that contaminant masses at a site follow a gamma distribution and that the data from the pre-remediation baseline sample as well as from the interim or final sample taken after a certain period of operation are both distributed as gamma with the same shape parameter but different scale parameters, we derive a uniformly most powerful unbiased test of the hypothesis that a specified percentage of contaminant mass has been reduced. A large-sample approximation of the exact test procedure and a comparison with the likelihood ratio test are provided.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050312
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  • 96
    Electronic Resource
    Electronic Resource
    The quality of mean and variance estimates for normal and lognormal data when the underlying distribution is misspecified (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 263-271 
    Details
    ISSN: 0886-9383
    Keywords: Mean ; Variance ; Lognormal ; Optimal estimators ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Theoretical and simulation results are employed to evaluate mean and variance estimates for normal data when a lognormal distribution is assumed and for lognormal data when a normal distribution is assumed. Misspecifying the distribution leads to the use of suboptimal estimation methods. However, the results show that the suboptimal methods still produce estimators of good quality (low bias and variance) relative to the minimum variance unbiased estimators for each distribution, at least when practical efficiency is considered.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050313
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  • 97
    Electronic Resource
    Electronic Resource
    Correspondence analysis used in the evaluation of lakewater chemistry in the Adirondacks (1991)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 273-290 
    Details
    ISSN: 0886-9383
    Keywords: Correspondence analysis ; Eastern Lake Survey - Phase I data ; Acidic deposition ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Correspondence analysis (CA) was applied to lakewater data in order to study the effects of acidic deposition on the geochemical composition of lakes in the Adirondacks. The lake chemistry data analyzed were taken from the Eastern Lake Survey - Phase I (ELS-I) conducted by the U.S. Environmental Protection Agency. CA was used to identify ‘outlying’ lake samples as well as ‘superflous’ and ‘unresolved’ analytes. Correlational relationship among analytes were also examined.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180050314
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  • 98
    Electronic Resource
    Electronic Resource
    Editorial (1991)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 73-74 
    Details
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240140202
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  • 99
    Electronic Resource
    Electronic Resource
    Structure-type separation of diesel fuels by solid phase extraction and identification of the two- and three-ring aromatics by capillary GC-mass spectrometry (1991)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 91-98 
    Details
    ISSN: 0935-6304
    Keywords: Gas chromatography ; Solid phase extraction ; Structure-type separation ; Polycyclic aromatic hydrocarbons (PAHs) ; Diesel fuel ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple and effective solid phase extraction (SPE) method using silica gel micro glass columns has been developed for the separation of diesel fuel into groups of aliphatic, and mono-, di- and polyaromatic hydrocarbons. It is based on a stepwise gradient of dichloromethane in n-pentane. The resulting fractions were analyzed by capillary gas chromatography with a flame ionization detector and coupled gas chromatography-mass spectrometry.Commercially available standards, and retention indices and mass spectra were used for identification of individual aromatic compounds. The principal polycyclic aromatic hydrocarbons (PAHs) in diesel fuel are naphthalene, biphenyl, fluorene, phen-anthrene and their alkylated derivatives. Sulfur-containing PAHs are mainly represented by methyl-substituted dibenzo-thiophenes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240140205
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  • 100
    Electronic Resource
    Electronic Resource
    Supercritical fluid solid chromatography using novel porous glassy carbon. Evaluation of retention mechanisms (1991)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 99-102 
    Details
    ISSN: 0935-6304
    Keywords: Supercritical fluid chromatography ; Adsorption chromatography ; Porous glassy carbon ; Retention mechanisms ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of a porous glassy carbon (PGC) material as a packed-column SFC stationary phase has been previously demonstrated [1]. The material is further characterized in terms of its retention characteristics. The effects of variations in mobile phase composition, pressure, and temperature conditions are evaluated. Variation of temperature and pressure yielded expected results, specifically, decreased solute capacity factors with increased mobile phase density. The choice of supercritical fluid mobile phase allows the most notable control of solute retention; this was evaluated by adding low percentages of organic modifiers of varying molecular weights to the supercritical carbon dioxide mobile phase. PGC-SFC provides reversed phase characteristics similar to those found for PGC-HPLC. Porous glassy carbon has selectivity characteristics previously unavailable in supercritical fluid chromatography. Use of porous glassy carbon in supercritical fluid chromatography may provide distinct advantages in difficult analytical separations, allowing separations of molecules with only slight structural differences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240140206
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