ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A model for the pattern of deposition of microfibrils in the cell wall of Glaucocystis (1978)
    Springer
    Planta 141 (1978), S. 51-58 
    Details
    ISSN: 1432-2048
    Keywords: Cell wall ; Cellulose ; Freeze-etching ; Glaucocystis ; Microfibrils (cellulose) ; Morphogenesis ; Plasma membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Freeze-fracturing of Glaucocystis nostochinearum Itzigsohn cells during cell-wall microfibril deposition indicates that unidirectionally polarized microfibril ends are localized in a “zone of synthesis” covering about 30% of the sarface area of the plasma membrane. Within this zone there are about 6 microfibril ends/μm2 cell surface. It is proposed that microfibrils are generated by the passage of their tips over the cell surface and that the pattern of microfibril organization at the poles of the cells, in which microfibrils of alternate layers are interconnected at 3 “rotation centres”, results directly from the pattern of this translation of microfibril tips. In a model of the deposition pattern it is proposed that the zone of synthesis may split into 3 sub-zones as the poles are approached, each sub-zone being responsible for the generation of one rotation centre. It is demonstrated that the microfibrillar component of the entire wall could be generated by the steady translation of the microfibril tips (at which synthesis is presumed to occur) over the cell surface at a rate of 0.25–0.5 μm min-1. Microcinematography indicates that the protoplast rotates during cell-wall deposition, and it is proposed that this rotation may play a role in the generation of the microfibril deposition pattern.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387744
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Further evidence from sectioned material in support of the existence of a linear terminal complex in cellulose synthesis (1987)
    Springer
    Protoplasma 136 (1987), S. 96-103 
    Details
    ISSN: 1615-6102
    Keywords: Boergesenia forbesii ; Microfibrils ; Microtubules ; Plasma membrane ; Sectioned material ; Terminal complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Transmembrane linear terminal complexes considered to be involved in the synthesis of cellulose microfibrils have been described in the plasma membrane ofBoergesenia forbesii. Evidence for the existence of these structures has been obtained almost exlusively using the freeze etching technique. In the present study an attempt has been made to complete these studies using conventional fixation, staining, and sectioning procedures. In developing cells ofBoergesenia forbesii, strongly stained structures traversing the plasma membrane and averaging 598.9 nm ± 171.3 nm in length, 28.7 nm ± 4.2 nm in width, and 35.2 nm ± 6.6 nm in depth have been demonstrated. These structures are considered to be linear terminal complexes. At their distal (cell wall) surface, they appear to be closely associated with cellulose microfibrils. At the proximal (cytoplasmic) surface, they are associated with microtubules and polysomes. A model of the possible interrelation of the terminal complexes and microtubules leading to the generation of cell wall microfibrils is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276358
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A new putative cellulose-synthesizing complex ofColeochaete scutata (1992)
    Springer
    Protoplasma 168 (1992), S. 51-63 
    Details
    ISSN: 1615-6102
    Keywords: Cellulose microfibril formation ; Chlorophyta ; Coleochaete scutata ; Freeze fracture ; Plasma membrane ; Terminal complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cells of the charophycean alga,Coleochaete scutata active in cell wall formation were freeze fractured in the search for cellulose synthesizing complexes (TCs) since this alga is considered to be among the most advanced and a progenitor to land plant evolution. We have found a new TC which consists of two geometrically distinctive particle complexes complementary to one another in the plasma membrane and occasionally associated with microfibril impressions. In the E-fracture face is found a cluster of 8–50 closely packed particles, each with a diameter of 5–17 nm. Most of these particles are confined within an 80 nm circle. In the P-fracture face is found an 8-fold symmetrical arrangement of 10 nm particles circumferentially arranged around a 28 nm central particle. The TCs ofC. scutata are quite distinctive from the rosette/globule TCs of land plants. The 5.5×3.1 nm microfibril inC. scutata is also distinctive from the 3.5×3.5 nm microfibril typical of land plants. The phylogenetic implications of this unique TC in land plant evolution are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01332650
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Effects of 2,6-dichlorobenzonitrile and Tinopal LPW on the structure of the cellulose synthesizing complexes ofVaucheria hamata (1992)
    Springer
    Protoplasma 166 (1992), S. 200-207 
    Details
    ISSN: 1615-6102
    Keywords: Cellulose formation ; 2,6-Dichlorobenzonitrile ; Freeze etching ; Plasma membrane ; Cellulose synthesizing enzyme complex ; Tinopal LPW ; Vaucheria hamata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of 2,6-dichlorobenzonitrile (DCB, a known inhibitor of cellulose synthesis) and Tinopal LPW (TPL, an agent which disrupts glucan crystallization) on the structure of cellulose synthesizing complexes (terminal complexes, TCs) in the xanthophycean algaVaucheria hamata were investigated. DCB (10 μM) inhibits nascent fibril formation from the TC subunit (based on the absence of impressions) although it does not alter the overall shape of the rectangular TC during the short treatment of 20 min. With a prolonged treatment (60 min), the arrangement of TC subunits becomes disordered, and particles generally exhibited as doublets of subunits are released from each other. DCB also interferes with the formation of the overall shape of the TC although it does not disturb the conversion into TC rows of the subunits (the zymogenic precursor of the TC) packed in the globules. A 15 min treatment with TPL (1 mM) destroys the TC integrity by reducing the subunits into small fragments or particulate aggregates. The particulate rows of the TC are interrupted at many points, and fragments and particulate aggregates are dispersed by prolonged treatment (45 min) with TPL. Unlike DCB, TPL inhibits the conversion of globule subunits into TC rows. New insights on the structural characteristics necessary for cellulose microfibril assembly and possible mechanisms for the biogenesis of theVaucheria TC come from these data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01322782
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    A quantitative adhesion test for thin polymer films on silicon substrates (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 1287-1292 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The standard 90° peel test was modified in order to apply it to testing adhesion of thin polymer films to surfaces of silicon substrates, such as the silicon nitride passivation layer used in our solid-state chemical sensors. The goal of this task was to develop a procedure for testing adhesion of both dry and wet films, which would yield repeatable, quantitative results quickly, and with simple sample preparation. It is important to produce valid comparisons of adhesion both over variations of a given polymer composition, and between films made of dissimilar polymer matrices. The method described herein could be applied to adhesion testing of a wide variety of thin polymer layers to solid surfaces.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070430709
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Crosslink density of elastomers. A new gas-chromatographic method (1974)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 18 (1974), S. 1079-1082 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The crosslink density of small microtomed samples of rubber vulcanizates has been determined using a gas-chromatographic method for estimating the amount of solvent in the swollen rubber. The method may be used for determining the variation in crosslink density through thick rubber articles, for determining the change in crosslink density after aging service, or, for the investigation of rubber bonds and interfaces.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1974.070180409
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The thermal diffusivity of natural rubber (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 451-459 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of thermal diffusivities of peroxide-cured and sulfur-cured rubbers, over the range 0-100°C and 0-75 phr of carbon, are described. They are based on the asymptotic time dependences of heating and cooling curves, recorded following quenching of the samples into baths at various temperatures. The diffusivities are shown to depend linearly on both temperature and carbon content, to reasonable accuracies over the ranges studied. Some theory bearing on measurement techniques is presented.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Absorption of water in polyimide resins and composites (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 57 (1995), S. 133-137 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of temperature, postcure, and fiber orientation on water absorption were examined for Kerimid® 723 bismaleimide resin. The effect of fiber orientation was also examined for Avimid® N and BASF X-5260. Water absorption in Kerimid® 723 was found to have an Arrhenius temperature dependence, depend on degree of postcure, and be independent of fiber orientation. BASF X-5260 water absorption was also found to be independent of fiber orientation. Avimid® N water absorption exhibited a strong dependence on fiber orientation. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070570202
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Direct visualization of synthetic cellulose formation via enzymatic polymerization using transmission electron microscopy (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 1319-1326 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The process of synthetic cellulose formation in an acetonitrile-buffer solvent system by enzymatic polymerization of β-cellobiosyl fluoride monomer using cellulase as a catalyst was visualized by transmission electron microscopy. Synthetic cellulose could be observed as soon as 30 s after initiation of the polymerization. A micellar phase separation occurred at the initial stage of the reaction. Irregular aggregates of cellulose were formed at the boundary of the micellar particles, suggesting that the interface is the site of polymerization. The cellulose product after treatment with hot surfactant solution was strongly labeled with cellobiohydrolase I-gold complexes, indicating that the produced polymer is cellulose. The electron diffraction pattern of the product showed the typical pattern of crystal structure of cellulose II.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1994.021950416
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Bioelectrocatalysis and diffusion kinetics glucose oxidase: Glucose reaction using a water-soluble 1,1′-dimethylferrocene-2-hydroxypropyl-β-cyclodextrin complex (1994)
    Weinheim : Wiley-Blackwell
    Electroanalysis 6 (1994), S. 391-396 
    Details
    ISSN: 1040-0397
    Keywords: 1,1′-dimethylferrocene-2-hydroxypropyl-β-cyclodextrin ; Inclusion complex ; Mediator ; Glucose ; Glucose oxidase ; Diffusion ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mediation of the glucose oxidase (GOx): glucose reaction by 1,1′-dimethylferrocene (DMF) solubilized in 2-hydroxypropyl-β-cyclodextrin (hpβCD) was studied. Cyclic voltammetry (CV) was used to examine the effects of complexation with hpβCD on the oxidation potential of DMF through the analysis of half-wave potentials. This indicated a one-to-one complex between DMF and hpβCD, with a formation constant of (1.2 ± 0.3) × 103 M-1 The working potential for electrodes using the mediator complex could be reduced by minimizing the hpβCD concentration, though a lower limit of 2.5 mM was observed for the 0.5 mM DMF solutions used in this work, below which the DMF became insoluble, and its electrochemistry was not well behaved.Cyclic voltammetry measurements at different scan rates were used to determine kinetic-parameters, resulting in a second-order rate constant for the reaction of oxidized DMF with reduced GOx of 3.4 × 104 M-1 s-1 to 1.9 × 104 M-1 s-1 for solutions containing 4 mM to 10 mM hpβCD. These values are on the order of one-quarter the literature value for free DMF and are in the range reported for ferrocene, indicating that the complexed DMF is able to function as an efficient mediator. The rate constant determined for 2.5 mM hpβCD was anomalously high and probably indicated insolubility of the DMF at this hpβCD concentration. A rate constant versus the hpβCD concentration plot was used as an indication of the lower limit of hpβCD concentration at which reproducible results could be obtained.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140060506
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...