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  • Gas chromatography  (32)
  • Electron microscopy  (27)
  • Springer  (59)
  • American Chemical Society
  • Annual Reviews
  • Blackwell Publishing Ltd
  • 2005-2009
  • 1990-1994
  • 1980-1984  (59)
  • 1982  (59)
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  • Springer  (59)
  • American Chemical Society
  • Annual Reviews
  • Blackwell Publishing Ltd
  • Wiley-Blackwell  (63)
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  • 2005-2009
  • 1990-1994
  • 1980-1984  (59)
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  • 1
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    Colloid & polymer science 260 (1982), S. 564-569 
    ISSN: 1435-1536
    Keywords: lin. Polyethylene ; Single crystals ; Heat of Fusion ; DSC ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Recently published results for solution crystallized PE single crystals have shown, that the experimental heat of fusionΔH * is higher, if the solvent is exchanged to silicon oil (oil suspension samples) as compared with dried mats. This has been interpreted by the collapse of the original hollow pyramids during drying, inducing lateral defects within the lamellae. The present investigation does not confirm this unexpected result.ΔH * of dried mats (T c 66 to 91 °C) and of the corresponding oil suspension samples agree within the rather small limits of experimental error. The crystallinities as derived fromΔH *, density or WAXS are in excellent agreement. SEM micrographs of cold fractured dried mats show their spongy macromorphology, but TEM micrographs of stained ultra-thin sections reveal the lamellar morphology of the walls, consisting of curved lamellae and stacked hollow pyramides. If a dried mat is sintered at room temperature, a dense transparent film is obtained with a rather regular stacked morphology of large flat lamellae.ΔH * of these films agrees with that of the original mat.
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  • 2
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    Development genes and evolution 191 (1982), S. 205-207 
    ISSN: 1432-041X
    Keywords: Chitin inhibition ; Nikkomycin ; Cuticle ; Electron microscopy ; Epilachna varivestis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nucleoside antibiotic nikkomycin has proved to be an effective inhibitor of chitin synthesis in the Mexican bean beetleEpilachna varivestis. Ultrastructural investigations show defects in the procuticular area after nikkomycin application which suggest the complete absence of chitin. A cuticle like this is inflexible and too brittle to satisfy its normal function as an exoskeleton. The individuals are not able to free themselves from the exuvia and finally die. Therefore nikkomycin seems to be a potential insecticide with high specifity.
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  • 3
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    Archives of microbiology 132 (1982), S. 10-13 
    ISSN: 1432-072X
    Keywords: Calcofluor White ; Cell wall structure ; Chlorella ; Electron microscopy ; Protoplast ; Ruthenium Red
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Among 12 strains ofChlorella ellipsoidea, C. vulgaris, andC. saccharophila tested, 4 strains (1,C. ellpsoidea; 2,C. vulgaris; 1,C. saccharophila) formed osmotically labile protoplasts after treatment with mixtures of polysaccharide degrading enzymes. The relationship between enzymatical digestibility and structure or composition ofChlorella cell walls were studied by electron microscopy and staining techniques with some specific dyes. The cell wall structures of the 12Chlorella strains were grouped into three types: (1) with a trilaminar outer layer, (2) with a thin outer monolayer, and (3) without an outer layer. Protoplasts were formed only from the strains with a cell wall of Type 2. In the strains with a cell wall of Type 1, the outer layer protected the inner major microfibrillar layer against enzymatic digestion. The cell wall of Type 3 was totally resistant to the enzymes; the chemical composition of the cell wall would be somewhat different from that of other types.
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  • 4
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    Archives of microbiology 133 (1982), S. 97-99 
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Thylakoid centers ; Photosynthetic membranes/thylakoids ; Membranes ; Membrane biogenesis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An ultrastructural study of four cyanobacteria (Anabaena cylindrica, Dermocarpa violaceae, Gleocapsa alpicola, Pleurocapsa minor) indicates the presence of previously undescribed thylakoid centers from which photosynthetic membranes (thylakoids) radiate. These peripherally located thylakoid centers are cylinders 30 nm wide by 320 nm long, consisting of globular subunits oriented in nonparallel stacked arrays. Thylakoids are attached to the outer surface of the cylinder along its longitudinal axis. Thylakoid centers appear to be functionally significant due to their structure, location and thylakoid association.
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  • 5
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    Archives of microbiology 131 (1982), S. 116-123 
    ISSN: 1432-072X
    Keywords: Cell wall ; Wall degradation ; Lysozyme ; Autolysines ; Electron microscopy ; Staphylococcus aureus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In contrast to former findings lysozyme was able to attack the cell walls ofStaphylococcus aureus under acid conditions. However, experiments with14C-labelled cell walls and ribonuclease indicated that, under these conditions, lysozyme acted less as an muralytic enzyme but more as an activator of pre-existing autolytic wall enzymes. Electron microscopic studies showed that under these acid conditions the cell walls were degraded by a new mechanism (i.e. “attack from the inside”). This attack on the cell wall started asymmetrically within the region of the cross wall and induced the formation of periodically arranged lytic sites between the cytoplasmic membrane and the cell wall proper. Subsequently, a gap between the cell wall and the cytoplasmic membrane resulted and large cell wall segments became detached and suspended in the medium. The sequence of lytic events corresponded to processes known to take place during wall regeneration and wall formation. In the final stage of lysozyme action at pH 5 no cell debris but “stabilized protoplasts” were to be seen without detectable alterations of the primary shape of the cells. At the same time long extended ribbon-like structures appeared outside the bacteria. The origin as well as the chemical nature of this material is discussed. Furthermore, immunological implications are considered.
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  • 6
    ISSN: 1612-1112
    Keywords: Teflon capillary columns ; Chemically modified teflon ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The preparation of teflon capillary columns employing direct coating of the stationary phase to the chemically modified teflon surface and the role of the chemically modified teflon in the separation mechanism are described. Two types of contributions from the modified teflon have been observed: nonspecific adsorption of the carbon surface and specific interactions of polar groups in the carbon skeleton. The use of polar liquid phases can eliminate adsorption due to the presence of polar groups in the modified teflon.
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  • 7
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    Chromatographia 16 (1982), S. 60-62 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Amines ; Derivatization ; Chloroformate esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The gas chromatographic analysis of amines after conversion to electron capture sensitive carbamates in two-phase systems has been studied. Hydrophilic compounds, for instance methylamine, are reacted with 2,2,2-trichloro-tert. butyl chloroformate. Quantitation below 10−7 M can be made by thermionic or electron capture detection. A hydrophobic amine, namely N,N-dimethyl-n-octylamine, was derivatized with 2,4,6-tribromophenyl chloroformate with addition of iodide ion to the aqueous phase. The favorable effect of iodide ion as well as the choice of pH and chloroformate ester is discussed.
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  • 8
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    Chromatographia 16 (1982), S. 98-102 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Rectangular channel ; Efficiency ; Capacity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Gas chromatographic experiments have been performed in a truly rectangular channel with a 60∶1 cross-sectional aspect ratio, constructed according to the field-flow fractionation technology. It is shown that the peak broadening is controlled by the thickness of the channel while the maximum load is determined by the largest cross-sectional dimension. However, even with its elongated configuration, the side walls contribute significantly to the band broadening of solutes with a high diffusivity. Good agreement is found between the experimental plate height data and the recent theoretical calculations of Golay [13] taking into account the side-wall effect.
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  • 9
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    Protoplasma 111 (1982), S. 206-214 
    ISSN: 1615-6102
    Keywords: Bark beetle ; Sensilla ; Chemoreceptors ; Mechanoreceptors ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The antennal sensilla inI. typographus are almost exclusively confined to the flattened terminal flagellar segment. The sensillar types have distinct distribution patterns in the three areas where they are found. Judging from the ultrastructural characteristics the following functions can be assigned to the sensillar types: chemoreception, single-walled and double-walled sensilla; chemoreception/mechanoreception, terminal-pore sensillum. Moreover there are two types of mechanoreceptors, one of which is connected to a bristle, whereas the other terminates within the cuticle of the flagellar segment.
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  • 10
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    Cell & tissue research 226 (1982), S. 589-608 
    ISSN: 1432-0878
    Keywords: Kidney (frog) ; Glomerulus ; Nephron ; Tight junctions ; Freeze-fracturing ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By the use of thin sections and freeze-fracture replicas the glomerular and tubular structures of the kidney of the frog (Rana esculenta) were studied with special reference to intercellular junctions. In the glomerulus the filtration barrier is of very variable thickness, and frequent tight and gap junctional contacts occur between podocyte processes. Although structurally less elaborate, the proximal tubule resembles its mammalian counterpart. In the initial part the tight junctions are relatively shallow but become very broad in the mid and distal portions of the proximal tubule. The proximal tubular cells are extensively linked by gap junctions. In some animals the shapes of the cells in the proximal and distal portions of the proximal tubule were markedly different. The distal tubule consists of two segments which differ mainly in the pattern of interdigitations and the structure of the zonulae occludentes. Similarities with the tight junctional morphology of the mammalian distal tubule are striking. In the first part of the distal tubule (diluting segment) a narrow band of parallel tight junctions is found closely resembling that found in the mammalian straight distal tubule; in the more distal part of the distal tubule, however, a broad band of anastomosing tight junctional strands exists, like the zonula occludens of the mammalian convoluted distal tubule. The connecting tubule displays cellular dimorphism: its wall contains a mixture of light and dark (flask) cells. The luminal and basolateral membranes of the flask cells are covered with numerous rod-shaped particles. The tight junctions of the connecting tubule are broad and increase in depth and number of strands along its length; they are typical of a very tight epithelium. In spite of several dissimilarities with phylogenetically younger kidneys our findings suggest that many structural principles of the mammalian kidney are also represented in the kidneys of amphibians. The structural-functional relationships are discussed.
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  • 11
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    Chromatographia 15 (1982), S. 704-706 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Isopropyliden-sorboses ; TMS-derivatives ; GC-MS combined technique ; Mass spectra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method has been developed using gas chromatography — electron impact mass spectrometry for the determination of the di-0-isopropylidene-sorbofuranose and mono-0-isopropylidene-sorbofuranose. The compounds are separated as their trimethylsilyl derivatives on a capillary column coated with the stationary phase SE-52. The mass spectra show that the silylation reaction is quantitiative and that the isopropylidene groups does not change.
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  • 12
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    Chromatographia 15 (1982), S. 183-185 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Analysis of ethylbenzene hydroperoxide ; Time normalization method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A gas chromatographic method, based on the time normalization technique, is described for the analysis of ethylbenzene hydroperoxide in mixtures containing ethylbenzene, acetophenone, 1-phenylethanol, benzaldehyde and phenol. Different liquid phases were tested and the best results were obtained with tricresyl phosphate and neopentyl glycol sebacate. The influence of the support, the liquid loading and the gas velocity are discussed.
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  • 13
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    Chromatographia 15 (1982), S. 625-630 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Open-tubular (capillary) columns ; Comparison of liquid phases ; Influence of temperature ; Retention index data
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The influence of temperature and liquid phase film thickness of open-tubular (capillary) columns on the retention index values of hydrocarbons on methylsilicone liquid phases is discussed. Data obtained on methylsilicones and squalane are compared. Retention index values of 43 hydrocarbons between 40 and 70 °C on OV-101 liquid phase are listed.
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  • 14
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    Chromatographia 15 (1982), S. 351-354 
    ISSN: 1612-1112
    Keywords: Supported catalysts ; Reserved-flow GC ; Drying step ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Application of reversed-flow gas chromatography to study the drying step in the preparation of supported catalysts is proposed. It is demonstrated that this technique can be applied to investigate the kinetic law followed, as well as to obtain kinetic parameters of drying (rate constants, activation energies and frequency factors). Amaterial illustrating this application is γ-Al2O3 impregnated with usual organic solvents (n-C5H12,n-C6H14,n-C7H16, CH3COCH3 and CH3CH2OH). It was found that in all cases above a simple first-order law based onone kind of active site is followed. Moreover, it was observed that the activation energyE a of the drying process increases almost linearly with the relative molecular mass of the solvent, whereas for the same solventE a increases with the amount used. The operation of a kinetic compensation effect suggests “similar” activated complexes of the various solvents used.
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  • 15
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Fused silica capillaries ; New polar phases: OV-1701 and RSL-310 ; Immobilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The possibilities of OV-1701 and RSL-310, two new stationary phases, have been evaluated for capillary gas chromatography in fused silica columns. OV-1701 is a cyanopropylphenyldimethyl polysiloxane of moderate polarity possessing excellent chromatographic characteristics. The phase exhibits high coating and chromatographic efficiencies, high temperature stability and is suitable for cross-linking. RSL-310 is a polar liquid stationary phase yet to be permanently bonded in a capillary column. The selectivity of both phases extends the applicability of fused silica columns.
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  • 16
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    Chromatographia 15 (1982), S. 241-244 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Monosaccharides ; Polyols ; GC of TMS derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This paper describes the gas chromatographic separation of the mixture of isopropylidene monosaccharides, and their trimethylsilyl derivatives. Based on the total analysis time and resolution the best stationary phase was SF-96 using Chromosorb G as the solid support and temperature programming.
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  • 17
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    Chromatographia 15 (1982), S. 312-314 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Injection-port modification ; Oxygen and nitrogen traces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The paper presents a new device modifying normal injection port of a gas chromatograph for eliminating air contamination thus enabling determination of traces of oxygen or nitrogen. Further modification is also proposed which enables the analysis to be carried out with a limited quantity of sample gas. Potential application of this device in the analysis of reactive gases like florine has been indicated.
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  • 18
    ISSN: 1612-1112
    Keywords: Phthalides ; Gas chromatography ; Chromosorb W ; Isomerization ; Ligustilide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary During GLC of naturally occurring mixtures of phthalides on packed columns an artefact was sometimes detected that originated from Z-ligustilide. Active sites of Chromosorb W were responsible for the formation of the artefact, that was assumed to be E-ligustilide as GC-MS revealed that its mass spectrum was identical with that of Z-ligustilide. No isomerization was observed when freshly coated Chromosorb W was used or the support was deactivated by benzoyl chloride or melamine. The identity of the artefact was confirmed by UV irradiation experiments.
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  • 19
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    Chromatographia 15 (1982), S. 30-32 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Arsenic ; Inorganic materials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the quantitative chlorination and extraction of arsenic as arsenic trichloride from a number of alloys. The conditions for the quantitative gas chromatographic measurement of the volatile chloride have been studied. The proposed method for inorganic materials is very fast giving results within 10 min; sensitive, 1.5·10−13 g As can be detected, simple and accurate. At the ng level of As the error is about 20% with a standard deviation less than 20%, and at the 10pg level the error is about 36% with a standard deviation of 44%.
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  • 20
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    Chromatographia 15 (1982), S. 765-768 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Preparative scale chromatography ; Capacity ; Dual-stage separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The capacity of different versions of single- and dual-stage separation of mixtures on a preparative scale is considered. It has been shown that dual-stage separation with intermediate condensation considerably enhances the capacity of the installation as compared with a single-stage process.
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  • 21
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    Chromatographia 15 (1982), S. 117-124 
    ISSN: 1612-1112
    Keywords: Various packed GC column ; Gas chromatography ; Porous layer beads ; GC/MS analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Theoretical comparisons of various packed GC column types are presented with respect to analysis time, efficiency, sample dilution, and sample capacity for a given maximum inlet pressure. In particular, totally porous particles, porous layer beads, and glass beads are compared with one another. It is shown that 30 μm porous layer beads offer a useful compromise between analysis time and plate count with relatively good sample capacity. Moreover, when using 1 mm i.d. columns (microbore), outlet flow rates that are reasonable for direct coupling to magnetic sector mass spectrometers are achieved making these columns suitable for GC/MS. Using 30 μm Zipax porous layer beads, columns yielding 8,000 to 10,000 plates/meter have been produced with inlet pressures of 13 to 26 atm. A simple modification of the injection port converts the maximum inlet pressure of a commercial gas chromatograph to 26 atm. With such pressures, columns in excess of 20,000 plates can be achieved. Chromatograms are presented illustrating the promise of these microbore columns for GC and GC/MS analysis.
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  • 22
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    Chromatographia 15 (1982), S. 245-248 
    ISSN: 1612-1112
    Keywords: Chromatoscopy ; Gas chromatography ; Graphitized carbon black ; Molecular structure and retention ; Aromatic hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A molecular-statistical calculation of the retention volumes at zero sample size on graphitized thermal carbon black is carried out for quasi-rigid molecules of fluorene, indene, 1-methylindene, 2-methylindene and three dimethylindenes. A reasonable agreement is observed between the calculated and the available experimental gas chromatographic data. The potential barrier to internal rotation and the torsional angle in styrene molecules are estimated by comparing theoretically calculated and measured retention volumes.
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  • 23
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Silicone liquid phases ; Oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The on-column oxidation of apolar and polar silicones used as gas chromatographic stationary phases is investigated. Even at 225° the effects of oxidation are found to be slight. Of the materials investigated the methylphenylsilicones are the most stable.
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  • 24
    ISSN: 1612-1112
    Keywords: Glass capillary ; Gas chromatography ; Methyl chloroacetates ; Methyl chloropropanoates ; Methyl chlorobutanoates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The gas chromatography of all chlorinated methyl acetates, methyl propanoates and methyl mono- and dichlorobutanoates has been studied on Carbowax 20M and SE-30 glass capillary columns under various running conditions. The order of elution on a non-polar column was largely determined by the boiling point of esters, whereas on a polar column it was much influenced by the structure of compounds. Complete separation of the combined mixture of all 27 compounds could not be achieved, however, methyl 3,3-dichlorobutanoate was the only ester overlapped on both columns in spite of the various column temperatures used. The best separation of the mixture was on Carbowax 20M with a temperature program from 50°C at 8°C/min, isothermal running conditions leading either to poor separation of volatile components or long analysis time and broad peaks of higher chlorinated esters. The relative retention times for compounds at the various column temperatures are given and the retention order on a polar and on a non-polar column discussed.
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  • 25
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    Chromatographia 15 (1982), S. 517-520 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Carbon-silica adsorbents ; n-Octadecanol film ; Phase transitions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The properties of the n-octadecanol film on carbon-silica adsorbent (Carbosil) were investigated. It was found that n-octadecanol forms an oriented film on the Carbosil's surface. If the surface of the basic silica gel is not completely covered with carbon, then the phase transition takes place in this film at a temperature higher than the melting temperature of n-octadecanol. One may distinguish two forms of this film, characterised by the different structures and the temperatures of the phase transitions. The first exists on the surface of silica gel unblocked by carbon. This part of the film is a monolayer, in which the alcohol molecules are vertically oriented. The solid compact-liquid expanded type phase transition at the well-defined temperature occurs in this film. In the second part of the film formed on the carbon surface, there is a multilayer of n-octadecanol. Its molecules are probably parallely oriented in relationship to the adsorbent surface. This film desintegrates progressively when the temperature increase. Maximum temperature of this phase transition is lower than the temperature of its analogue on pure silica gel surface.
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    Chromatographia 15 (1982), S. 546-558 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Capillary columns ; Quantitative analysis ; Sample inlet systems ; High-speed analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The attainment of precise quatitative analytical data using open-tubular (capillary) columns in standard, commercially available gas chromatographic instrumentation is demonstrated. Key elements in the design and proper utilization of the instrumentation are discussed. The function of the various sample introduction systems is elaborated and their quantitative performance demonstrated. The extra-column contribution to band-spreading is determined and the resultant data is used assessing the suitability of commercial instrumentation for highspeed capillary gas chromatography. The quantitative analysis of a sample containing some eleven components in less than thirty seconds is shown.
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  • 27
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Crystal hydrates as stationary phases ; Mobile Phases containing water ; Selective retentions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of crystallohydrates, crystallohydrate solutions and melts as stationary phases in gas chromatography has been proposed. Crystallohydrates have been shown to display high selectivity in the separation of polar organic compounds when use is made of water vapours as the mobile phase. Some aspects of gas-liquid chromatography in water vapours and with the stationary phase comprising crystallohydrates have been studied, and the preliminary results obtained point to the desirability of further progress in this field.
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    Chromatographia 16 (1982), S. 201-203 
    ISSN: 1612-1112
    Keywords: Phenols ; Whisky ; Gas chromatography ; Aroma compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Twelve volatile phenols were identified in whisky by combined gas chromatography-mass spectrometry. Of these phenols 2,4-dimethylphenol was found for the first time in the aroma of whisky. The content of phenol, o-, m-, and p-cresol, guaiacol, p-ethylphenol, p-ethylguaiacol and eugenol in whiskies originating from different countries was determined by gas chromatography as their 2,4-dinitrophenyl ethers using electron capture detection. The results show that Scotch whiskies differ from others in the content of o-, m-, and p-cresol. The odour threshold values of phenols studied were determined in a 10% (v/v) ethanol-water mixture and in some cases also in the whiskies. Cresols have been found to make contribution to the aroma of Scotch whisky.
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  • 29
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    Chromatographia 16 (1982), S. 26-31 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Ionization detectors ; Gaia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This paper is an account of the development of the gaia hypothesis as seen through the eyes of a gas chromatographer. Gaia is a radical notion about the Earth which postulates the climate and chemical composition to be regulated at an optimum by and for life. Gas chromatography played an important role in the gathering of evidence for the hypothesis but most significantly the art of inventing detectors lead to the developement of a planetary life detector through which gaia was revealed.
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    Chromatographia 16 (1982), S. 282-285 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Naphtha analysis ; Gasoline analysis ; Hydrocarbon type analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Two different gas chromatographic methods are used for the determination of hydrocarbon type distribution in naphtha and gasoline samples with final boiling points up to 275 °C. The methods are based either on a single capillary column or on a valve-switched packed column system. Both methods give extensive information on paraffins, olefins, naphthenes and aromatics in total as well as by carbon-number. In each case the analysis is fully automated with a computer controlling the entire analysis from injection to results presentation. The advantages and limitations of both methods are discussed.
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    Chromatographia 16 (1982), S. 322-324 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Graphitized carbon black supports ; Determination of hydroxyacids
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    Topics: Chemistry and Pharmacology
    Notes: Summary Acid-washed graphitized carbon black (Carbopakc B) modified with trimesic adic and PEG 20M has proved to be effective for quantitative analysis of underivatized low molecular weight hydroxyacids. Calibration data revealed good linear relationships between relative peak area and concentration for lactic and 3-hydroxybutyric acids down to 0.05 mmol/l. The packing material was suitable for the analysis of aqueous solutions of hydroxyacids as it is tolerant to injections of water over a prolonged period of use. The GC system developed has been applied to the analysis of some hydroxyacids of biomedical interest in blood plasma and lactic acid contained in wine and beer.
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  • 32
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Modified thermal energy analyzer ; Selective detection of nitrogen compounds
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    Topics: Chemistry and Pharmacology
    Notes: Summary A modification to the TEATM Analyzer is described, which allows it to be used as a highly selective GC detector for nitrogen compounds as well as for N-nitrosamines and nitro compounds. The modified Analyzer is as sensitive as the AFID, but has a much higher selectivity towards nitrogen compounds than the AFID. Its response appears to be molar, with an output that is dependent only on the number of nitrogen atoms present. The performance of the modified Analyzer for the analysis of ammonia, amines,N-nitrosamines, nitriles and organonitro compounds is reported and discussed, as is its application to the detection of these compounds in bacon and beer samples.
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  • 33
    ISSN: 1612-1112
    Keywords: Graphizized carbon black traps ; Organic air pollutants ; Work areas ; Gas chromatography
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    Topics: Chemistry and Pharmacology
    Notes: Summary The use of traps containing graphitized carbon black for the collection and pre-analysis of atmospheric pollutants in industrial areas is presented. The working conditions, in terms of trapping capability and effectiveness of release by thermal desorption are discussed. Some practical applications are also given.
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  • 34
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Van der Waals' volume ; Polarity of stationary phase ; Retention index
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    Topics: Chemistry and Pharmacology
    Notes: Summary Equations for Retention Index (I) versus Van der Waals, volume (Vw) on squalane are studied for alcohols, carbonyls, esters and ethers. Each equation includes linear and branching substances with different positions of the functional group in the carbon chain. The study is extended to stationary phases with polarities from 4.29 to 91.54 on the Tarjan et al. scale. Variations of the slope and origin ordinate values with the polarity of the stationary phase are discussed.
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  • 35
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    Chromatographia 15 (1982), S. 125-132 
    ISSN: 1612-1112
    Keywords: Capillary columns ; Fast analysis ; Gas chromatography ; Instrumental effects ; Optimization
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    Topics: Chemistry and Pharmacology
    Notes: Summary The efficiency of fast GC columns depends largely on the quality of the chromatograph. A theoretical and experimental study shows the relative importance of the various phenomena involved and permits the optimization of a GC System. Extremely good performances, exceeding 2,500 plates per second have been routinely obtained.
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  • 36
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    Chromatographia 15 (1982), S. 180-182 
    ISSN: 1612-1112
    Keywords: Acidic fermentation products ; Characterisation ; Gas chromatography ; Methyl esters
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    Topics: Chemistry and Pharmacology
    Notes: Summary A rapid and simple method for the identification of acidic fermentation products is described. Methyl esters of volatile and non-volatile acids are separated on a single chromatographic column. Retention time data for a number of acids are tabulated.
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  • 37
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    Chromatographia 15 (1982), S. 521-524 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention index ; Connectivity index ; Van der Waals' volume ; Alkanes
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    Topics: Chemistry and Pharmacology
    Notes: Summary The relationships between retention index and Van der Waals' volume and between retention index and connectivity index have been studied for 58 different alkanes (C1−C9) on squalane. The correlation coefficient for the former is higher than for the latter. From these equations a linear relationship between Van der Waals' volume and connectivity index is obtained which indicates that the two parameters are equivalent. A simple method for calculating the Van der Waals' volume of alkanes is proposed.
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  • 38
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Capillary columns ; Fused silica capillaries ; Capillary drawing ; Glass capillaries
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    Topics: Chemistry and Pharmacology
    Notes: Summary A compact description is given of a simple and reliable method of drawing flexible fused silica capillary for gas chromatography. Some emphasis is given to the fact that the practices of drawing optical fibres should not be followed too slavishly so this leads to unnecessarily complicated and expensive equipment. Satisfactory capillary column silica tubing can be made with straightfoward extension of the method developed earlier for drawing thick walled capillary. A simple glass/silica hydrogen oxygen diffusion flame bumer is described for fusing the preform tubing at the draw point which is enclosed by a water cooled glass enclosure to trap evaporated silica and maintain the operation under dust free conditions. The uniformity of the capillary diameter is better than 5% which is adequate for most gas chromatographic purposes. The second part of the paper yet to be published will cover the methods developed for coating the capillary both internally and externally.
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  • 39
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    Chromatographia 16 (1982), S. 107-111 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Thermionic ionization ; Catalytic flame ionization
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    Topics: Chemistry and Pharmacology
    Notes: Summary A newly designed thermionic detector was operated in two modes of thermionic ionization detection (TID), and a third mode of catalytic flame ionization detection (CFID). Operating modes were varied by changing the composition of the electrically-heated thermionic/catalytic source, and the composition of gases supplied to the detector. A TID-2 source activated by a low concentration of Cs/ceramic was operated in a dilute H2/air environment and provided specific responses to nitrogen and phosphorus compounds. A TID-1 source activated by a high concentration of Cs/ceramic was operated in a N2 environment and provided very high specificities and picogram detectivities to compounds containing electronegative functional groups such as the NO2 group. A CFID source formed from Ni/ceramic was operated in a H2/air flame environment and provided universal responses to all organics with enhanced responses to some heteroatom compounds.
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  • 40
    ISSN: 1432-0878
    Keywords: Stomach (Teleost) ; Endocrine cells ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary In the gastric mucosa of two teleost species, the perch (Perca fluviatilis) and the catfish (Ameiurus nebulosus) three endocrine cell types were found, located predominantly between the mucoid cells of the gastric mucosa. A fourth cell type is present in the gastric glands of catfish. Each cell type was defined by its characteristic secretory granules. Type-I cells were predominant in both fish. These cells contained round or oval granules with a pleomorphic core. The average diameter of granules was 400 nm for the perch and 270 nm for the catfish. Type-II cells of both species displayed small, highly osmiophilic granules about 100 nm in diameter. The secretory granules of type-III cells (260 nm in the perch and 190 nm in the catfish) were round or slightly oval in shape and were filled with a finely particulate electron-dense material. Type-IV cells of the catfish were found in the gastric glands only. Their cytoplasm was filled with homogeneous, moderately electron-dense granules averaging 340 nm in diameter. The physiological significance of these different morphological types of gastric endocrine cells requires further investigation.
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  • 41
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    Cell & tissue research 222 (1982), S. 409-415 
    ISSN: 1432-0878
    Keywords: Crustacean compound eye ; Eighth retinular cell ; Crystalline tract ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The base of the crystalline tract, the distal part of the eighth retinular cell and its rhabdomer constitute a structural unit in the apical region of the retinula of Astacus fluviatilis and A. leptodactylus, shielded from the blood by a special covering cell.
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  • 42
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    Cell & tissue research 224 (1982), S. 637-645 
    ISSN: 1432-0878
    Keywords: Cell surface antigen ; Neurons ; Glia ; Electron microscopy ; Immunoperoxidase ; Monoclonal antibody
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    Topics: Biology , Medicine
    Notes: Summary Immuno-electron microscopy was performed on live, cultured, early postnatal cerebellar and retinal cells of the mouse to identify A2B5 antigenbearing elements. In cerebellar cultures, granule cells, some immature oligodendroglia, and astroblasts express A2B5 antigen on their cell surfaces. The typical features of astroblasts include large cisternae of the endoplasmic reticulum and a mixed population of intermediate-sized filaments and microtubules. Immature oligodendroglia cells express the antigen on their cell bodies and on procecesses filled with cytoplasm. Cytoplasm-free membranous whorls, however, are devoid of A2B5 antigen, but not of 0 or NS-1 antigens. In retinal cultures, A2B5 antigen is observed on differentiating neurons with the exception of photoreceptor cells as identified by ribbon synapses.
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  • 43
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    Cell & tissue research 224 (1982), S. 673-683 
    ISSN: 1432-0878
    Keywords: Pacinian corpuscles, rat ; Denervation ; Sensory terminals ; Nerve degeneration ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Pacinian corpuscles located on the crural interosseous membrane was studied in adult rats 6 h to 10 months after transection of the right sciatic nerve. Axon terminals degenerated one day after transection and were engulfed and resorbed by cells of the inner core within one week. The axial space left after removal of the axonal debris was closed by the lamellae of the inner core. The main structural features of the inner core and capsule remained preserved after denervation throughout the period of study. The denervated inner cores, however, became atrophic 10 months after neurotomy, their mean diameter being reduced by 17.5% compared with that of contralateral control corpuscles. The number of capsular lamellae was unaltered, and perineurial pathways of the peripheral nerve stump remained preserved. Schwann cells proliferated and formed Büngner bands during the first month after denervation, but retracted their processes and became atrophic at later stages after neurotomy. Survival of Pacinian corpuscles after long-term denervation in adult rats is in contrast to their rapid degeneration within several days after nerve section in neonates.
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  • 44
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    Keywords: Electron microscopy ; Junctions ; Smooth muscle ; Echinodermata ; Holothuria, Aspidochirotida
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    Topics: Biology , Medicine
    Notes: Summary Electron microscopy reveals that sarcolemmata of adjacent muscle cells form pentalaminar junctions by fusion of apposed trilaminar double leaflet membranes. These junctions appear to be candidates for low resistance pathways between muscle fibers. The muscles depolarize slowly when bathed in solutions containing elevated concentrations of KCl, and the sucrose gap method can then be used to measure the potential difference between polarized and depolarized regions. Thus the junctions which we have observed may provide the structural basis for electrical transmission through the sucrose gap.
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  • 45
    ISSN: 1432-0878
    Keywords: Peritrophic membrane ; Tick ; Babesia ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary A peritrophic membrane (PM) has been demonstrated in the gut of feeding larvae, nymphs, and adults of the tick Ixodes dammini. This is the first report of a PM in ticks. This temporary structure divides the lumen of the gut into two compartments, an endoperitrophic space, the lumen proper, and an ectoperitrophic space located between the PM and the epithelial cells of the gut wall. The PM is a mechanical barrier and even such small particles as ribosomes derived from ingested reticulocytes are retained in the lumen proper; they are never found in the ectoperitrophic compartment. In Ixodes dammini fed on hamsters infected with Babesia microti some of the parasites are found in the ectoperitrophic space. This passage is accomplished by a highly specialized organelle, the arrowhead, which develops in some Babesia during their metamorphosis in the gut of the vector. The arrowhead, while passing through the PM, changes its fine structure and loses its internal organization as if releasing some of its contents. Its disintegration continues and it disappears shortly after the Babesia have entered the epithelial cells. Only Babesia equipped with the arrowhead structure are able to cross the PM. This is the first documented case of a parasite traversing a solidified PM.
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  • 46
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    Cell & tissue research 222 (1982), S. 25-40 
    ISSN: 1432-0878
    Keywords: Paddle cilia ; Discocilia ; Pleurobranchaea ; Chemoreceptors ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary Scanning electron microscopy of various regions of the body of the marine gastropod Pleurobranchaea californica (McFarland) has revealed a characteristic cell type that bears cilia with dilated discoid-shaped tips. The tips of the cilia consist of an expansion of the ciliary membrane around a looped distal extension of the axoneme. These kinocilia have been observed in numerous other marine invertebrates and are generally referred to as paddle cilia (Tamarin et al. 1974) or discocilia (Heimler 1978). Although many functions have been proposed for paddle cilia, little empirical evidence supports any of the proposals. In Pleurobranchaea we have found that the distribution of this ciliated cell type corresponds exactly to areas of the body known from behavioral studies (Lee et al. 1974; Davis and Matera 1981) to mediate chemoreception. Transmission electron microscopy of the epithelium lining the rhinophores and tentacles of Pleurobranchaea revealed details of the ultrastructure of these ciliated cells and showed that they are primary receptors. These ciliated receptors lie in a yellow-brown pseudostratified columnar epithelium that superficially resembles the olfactory mucosa of vertebrates.
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  • 47
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    Cell & tissue research 222 (1982), S. 167-175 
    ISSN: 1432-0878
    Keywords: Pigment granules ; Chromatophores ; Granulogenesis ; Palaemonid shrimp ; Macrobrachium ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary The possible biogenesis of two pigment granule types present in the monochromatic, brown chromatosomes enveloping the ventral nerve chord of the freshwater palaemonid shrimps Macrobrachium acanthurus, M. heterochirus and M. olfersii is examined by transmission electron microscopy in thin section and freeze fracture replicas. Prominent, membrane limited granules are suggested to have their origin in a complex, juxtanuclear, smooth endoplasmic reticulum labyrinth, continuous with the nuclear envelope. Amembranous, lipocarotenoid granules possibly derive from the external surface of the smooth endoplasmic reticulum. Nuclear envelope and SER membranes contain numerous 11 nm diameter intramembranous particles while pigment granule membranes exhibit fewer particles. A dictyosomal origin for the lipocarotenoid granules is discounted. Granulogenesis is suggested to be a continuous process in crustacean chromatophores.
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  • 48
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    Cell & tissue research 222 (1982), S. 261-267 
    ISSN: 1432-0878
    Keywords: Skeletal muscle ; Fiber types ; Electron microscopy ; Stereology ; Chicken
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    Topics: Biology , Medicine
    Notes: Summary Ultrastructural and stereological assessment of the mature avian anterior latissimus dorsi (ALD) muscle showed that it contains two kinds of extrafusal fibers. This fine structural dichotomy of fiber types in the ALD correlated well with their previously reported histochemical duality. Distinct differences occur in sarcomere banding, myofibrillar area, sarcotubular and mitochondrial density, and in morphology of motor-nerve terminals. Both myofiber types in this muscle were interpreted as representing varieties of “slow” or tonic muscle fibers. Both fibers contain myofibrils that, despite differences in cross-sectional area, were large, irregular, and ribbon-shaped, typical of the “Felderstruktur” appearance of true “slow” fibers. Whereas the majority of fibers (type-1) are devoid of well-defined M-bands, the minor fiber population (type-2) exhibit prominent M-bands in the center of each sarcomere. In addition, type-1 tonic fibers contain a significantly lower mitochondrial and sarcotubular volume than the tonic fibers of type-2. While both fiber types exhibit motor-nerve terminals that are small, smooth and punctate in appearance, those on the type2 fibers often had a number of shallow postjunctional folds. Whether or not these two classes of extrafusal fiber in this muscle represent two separate and distinct types of motor units remains to be determined functionally.
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  • 49
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    Cell & tissue research 223 (1982), S. 87-99 
    ISSN: 1432-0878
    Keywords: Smooth muscle cells ; In vitro-growth ; Whole blood serum ; Plasma-derived serum ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary Normal diploid cells require serum to proliferate in culture. Platelet-derived growth factor has been identified as the main serum component responsible for this effect. Here, smooth muscle cells were isolated enzymatically from the aorta of 5-day-old rats and cultured in the presence of 10% whole blood serum (WBS) or plasma-derived serum (PDS), i.e. with or without platelet factor, and studied by transmission electron microscopy. The cells proliferated actively in WBS-medium but remained quiescent in PDS-medium. Fine structurally, cells from WBS-cultures demonstrated numerous mitochondria, an extensive rough endoplasmic reticulum (RER), a large Golgi complex, a few lysosomes, and microfilaments arranged in parallel bundles. After transfer to PDS-medium, the RER- and Golgi cisternae were markedly dilated and the number of membrane-associated ribosomes decreased. Segregation of fragments of cytoplasm within autophagosomes was frequently observed and the number of lysosomes increased. Lipid droplets were more abundant and often gathered in the Golgi area. Moreover, the cells had become more irregular in shape and showed many bleb-like processes at their surface. Microfilament bundles had also become more prominent and crossed each other in different directions. These observations show that the removal of platelet factor from the medium clearly modifies the fine structure of cultured smooth muscle cells. The findings are in good agreement with the concept that platelet factor not only supports the proliferation of cultured cells but also stimulates their secretory activity.
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  • 50
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    Cell & tissue research 223 (1982), S. 267-280 
    ISSN: 1432-0878
    Keywords: Retina (Astacus) ; Rhabdom ; Osmolarity ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary Alterations of the retinula cells in the retina of the light-adapted crayfish in response to hyper- and hypoosmotic van Harreveld solutions was examined by transmission electron microscopy. Increased osmolarity of the bathing medium to twice that of the physiological value leads to shrinkage of the retinula-cell somata. Microvilli, on the other hand, do not undergo shrinkage. Some other characteristic irreversible changes do, however, take place, including detachment of microvilli from the soma, showing a two- or threefold increase in diameter, and a concomitant decrease in number, probably due to fusion of microvilli. Prolonged incubation or higher osmolarities (5 isosmol) cause alteration of the microvillar membranes to whorls. Structural changes are often restricted to microvillar stacks evaginating from certain individual retinular cells. The number of affected stacks increases depending on the duration of incubation or the osmotic pressure. Hypoosmotic solution (0.5 isosmol) also induces an increase of microvillar diameters and a concomitant reduction in number of microvilli per stack. Exposure to a 20% solution of glycerol causes destruction of the rhabdom structure and the formation of whorls from microvillar membranes. The present findings suggest that the structure of the microvilli is stabilized by an axial cytoskeleton.
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  • 51
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    Cell & tissue research 224 (1982), S. 291-301 
    ISSN: 1432-0878
    Keywords: Thymus (rat) irradiation ; Electron microscopy ; Interdigitating cells ; Macrophages ; Phagocytosis
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    Topics: Biology , Medicine
    Notes: Summary Phagocytic activity and population development of medullary interdigitating cells (IDC) and cortical macrophages have been studied in the rat thymus after irradiation-induced thymocyte necrosis. IDC clearly demonstrate phagocytic activity, particularly in the 16h stage after irradiation. At this stage the number of necrotic thymocytes is maximal and the total number of phagocytic cells is insufficient to phagocytize all necrotic material. IDC increase in number slightly and are predominantly phagocytizing in the corticomedullary region (CMR), where they appear to develop from macrophage-like cells. The results indicate that medullary IDC can be phagocytic but have a different developmental pathway than cortical macrophages. Cortical macrophages greatly increase in number and acquire the appearance of tingible body macrophages by phagocytizing many necrotic thymocytes. They seem to develop from monocytes that normally enter the thymus at the CMR. During the acute involution macrophages probably also enter the cortex via the connective tissue capsule. It is suggested that thymus medullary IDC probably belong to the mononuclear phagocytes, as do the cortical macrophages. In the specific medullary environment IDC gradually develop their characteristic ultrastructure for an apparently other than phagocytic function. The similarities between IDC and epidermal Langerhans cells are discussed.
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    Cell & tissue research 224 (1982), S. 349-359 
    ISSN: 1432-0878
    Keywords: Ovarian follicle ; Ovulation ; Ultrastructural change ; Fowl ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary No structural changes could be observed in the stigma until 2 h before ovulation. Within a few minutes of ovulation, the stratum granulosum and theca interna disappear completely in the middle part of the stigma. By 30 min before ovulation, the rough endoplasmic reticulum in the fibroblasts of the theca externa develops conspicuously. Then a few minutes before ovulation, the theca externa becomes much thinner with a conspicuous disintegration of the collagenous fibers into individual fibrils. These structural changes may contribute to the fragility of the stigma tissue and induce rupture of the follicle.
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  • 53
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    Cell & tissue research 224 (1982), S. 383-395 
    ISSN: 1432-0878
    Keywords: Mouse ovary ; Junctions ; Freeze-fracture ; Electron microscopy
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    Topics: Biology , Medicine
    Notes: Summary Intercellular junctions in the young mouse ovary were examined by electron microscopy utilizing freeze-fracture and thin-sectioning techniques. Projections from the granulosa cells adjacent to the oocyte (GI) traverse the zona pellucida and form small gap junctions on the oocyte surface. On the P-face of these cells, the junctional aggregations are occasionally associated with linear strands of particles. In contrast, large gap junctional areas are frequently observed between the more peripherally located granulosa cells (GE) and are also present in the theca interna (TI) cell layer surrounding the follicles. Three types of tight junctional strands are discernible on the P-face of theca externa cells (TE): angularly zigzag strands consisting of intermittently distributed intramembranous particles on wide ridges, intermediate zigzag strands consisting of more continuously distributed particles, and wavy strands consisting of rather fused particles. Tight junctional strands are also present in the middle of grooves on the E-face of endothelial cells of blood vessels. In the germinal epithelial cell layer, tight junctional strands appear to be discrete and form a less anastomosing network.
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    Cell & tissue research 224 (1982), S. 369-381 
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Pars intermedia ; Electron microscopy ; Fetal sheep ; Lamb
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    Topics: Biology , Medicine
    Notes: Summary Using light and electron microscopy, the morphogenesis of the pars intermedia of the sheep pituitary gland was examined in developing lambs between 26 days of gestation and the newborn stage. Following the establishment of contact between the anterior and posterior lobe primordia seen at 26 days, the connection with the pharyngeal roof disappeared by 31 days. The lumen of Rathke's pouch, which was a prominent cavity at the earlier stages, became inconspicuous by 40 days but progressively increased in size during gestation and, in some newborn animals, contained colloid material. At 40 days, the pars intermedia consisted of a uniform population of undifferentiated cells. Cells with cytoplasmic granules were first identified at 50 days. The cytological appearance of granular cells at 70 days indicated increased synthetic activity and by 80 days they closely resembled adult glandular cells. At 100 days, membrane activity suggestive of exocytosis was first observed in granular cells; fenestrated capillaries were present, and early follicle formation between adjacent non-granular cells was seen. This apparent exocytotic release of granules was observed much more frequently between 100 days of gestation and the newborn stage than in adult pars intermedia cells. These findings indicate that glandular cells of the developing pars intermedia are actively engaged in synthesis, storage and secretion from an early stage.
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    Cell & tissue research 225 (1982), S. 355-364 
    ISSN: 1432-0878
    Keywords: Implantation ; Blastocyst ; Pontamine ; blue reaction ; Decidualization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The early uterine response to transplanted, delayed and estrogenactivated blastocysts was studied ultrastructurally and compared with that induced by intrauterine instillations of deciduogenic agents (arachis oil, air). The uterine responses to delayed and activated blastocysts showed no ultrastructural or temporal differences. Already within 4 h after transfer to a sensitized uterus, the delayed blastocysts exhibited signs of activation, and both types of blastocysts had started to attach onto an undamaged epithelial lining. Signs of stromal cell differentiation into decidual cells were also seen as early as 4 h after transfer, while the Pontamine-blue reaction did not appear until after 8 h. The results therefore indicate that the transplanted blastocysts induced decidualization atraumatically and that the delayed blastocysts were either deciduogenic already before transfer or rapidly acquired deciduogenic properties after transfer. Artificial decidual induction with oil and air led to damage or death of a large number of cells in the uterine luminal epithelium. Within only 15 min after instillation pronounced signs of cell damage were seen, and later numerous cells were extruded from the epithelial lining. In the stroma ultrastructural signs of decidual cell differentiation and a Pontamine-blue reaction were observed as early as 4 h after induction. It is therefore suggested that oil and air induce decidualization via the epithelium by means of trauma.
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    Cell & tissue research 225 (1982), S. 443-448 
    ISSN: 1432-0878
    Keywords: Frog cerebellum ; Ependymal surface ; Cilia ; Supraependymal cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural studies of the ventricular surface of the frog cerebellum showed regional differences. In the midline region of the adult cerebellum was found a band of profusely ciliated squamous ependymal cells. In the rest of the cerebellum the ependymal cells were columnar and each had a single cilium. In the cerebellum of the premetamorphic tadpole, the squamous ependymal cells of the midline region also were monociliated. During metamorphosis they gradually became multiciliated. Additionally, supraependymal cells and synaptic elements were present on the ventricular surface of the cerebellum of adult frogs as well as in late metamorphic tadpoles. In contrast, supraependymal cells were rarely observed in premetamorphic tadpoles, and it was concluded that the supraependymal system develops during metamorphosis. It is postulated that the band of cilia may be associated with the circulation of cerebrospinal fluid, and supraependymal synaptic elements function in neuroendocrine regulation.
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    Cell & tissue research 225 (1982), S. 663-671 
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    Keywords: Chaetognatha ; Intestine ; Pleated septate junction ; Electron microscopy ; Freeze-fracture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The intramembrane structures of the pleated septate junction which occur in the junctional complex of the intestine of the chaetognath Sagitta setosa have been investigated. The pleated septate junction is made up of linear rows of irregularly shaped and sized particles, often fused into short rods, and pits which can be fused into furrows. The distribution of these structures on E and P faces depends upon the preparative methods used. Many of the morphological characteristics are the same as those of the “lower invertebrate pleated septate junction type” defined by Green (1981a). The physiological significance of this junction is obscure. On the basis of the presence of septate junctions (both of the paired septate junction and pleated septate junction types) which have mainly morphological characteristics of the “lower invertebrate pleated septate junction” we can add to the hypothesis that chaetognaths are not related to the molluscs and arthropods.
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  • 58
    ISSN: 1432-0878
    Keywords: Enteroendocrine cells ; Pancreatic endocrine cells ; Gastroenteropancreatic hormones ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Four immunoreactive endocrine cell types can be distinguished in the pancreatic islets of B. conchonius: insulin-producing B cells, somatostatin-producing A1 (= D) cells, glucagon-producing A2 cells and pancreatic poly-peptide-producing PP cells. The principal islet of this species contains only a few PP cells, while many PP cells are present in the smaller islets. Except for the B cell all pancreatic endocrine cell types are also present in the pancreatic duct. At least six enteroendocrine cell types are present in the gut of B. conchonius: 1. a cell type (I) with small secretory granules, present throughout the intestine, and possibly involved in the regulation of gut motility; 2. a C-terminal gastrin immunoreactive cell, probably producing a caerulein-like peptide; these cells are located at the upper parts of the folds, especially in the proximal part of the intestinal bulb; 3. a met-enkephalin-immunoreactive cell, present throughout the first segment; 4. a glucagon-immunoreactive cell, which is rare in the first segment; 5. a PP-immunoreactive cell, mainly present in the first half of the first segment; 6. an immunoreactive cell, which cannot at present be specified, located in the intestinal bulb. The latter four cell types are mostly located in the basal parts of the folds, although some PP-immunoreactive cells can also be found in the upper parts. Most if not all enteroendocrine cells are of the open type. The possible functions of all enteroendocrine cell types are discussed.
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  • 59
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 226 (1982), S. 327-335 
    ISSN: 1432-0878
    Keywords: Xenopus ; Spleen ; B-lymphocyte ; Immunofluorescence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An indirect immunofluorescence study of the frozen sections of the spleen of an anuran amphibian, Xenopus laevis, showed that lymphocytes bearing a small amount of immunoglobulin (Ig) were localized mostly in the white pulp of non-immunized toads. There were fewer fluorescent cells in the red pulp. In the toads hyperimmunized with human gamma globulin (HGG), cells with strong cytoplasmic fluorescence increased significantly in the outer part of the white pulp. Electron microscopy of spleens from these toads showed that plasma cells at different stages of maturation were abundant in the white pulp, whereas in the red pulp, a smaller number of maturer plasma cells were observed. These results indicate that, in contrast with its mammalian counterpart, the splenic white pulp of this anuran is the site where thymusin-dependent lymphocytes commence blast formation and transformation into plasma cells.
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