Library

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 1970-1974  (5)
  • 1965-1969  (3)
  • Physics  (6)
  • Cell & Developmental Biology  (2)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 179 (1974), S. 253-271 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Ultrastructural changes of rat blastocysts during delayed implantation were studied 16, 20, 24 or 30 hours after estrogen was given to induce implantation.In the inner cell mass the presence of long cytoplasmic processes penetrating deeply into the neighboring inner cell mass cells is seen at 16 hours. Most cells also show an increased number of ribosomes, polyribosomes and granular endoplasmic reticulum.The trophoblast is featured by the formation of large amounts of glycogen and many inclusion bodies. Glycogen granules appear first in some abembryonic trophoblast cells at 16 hours, and spread to the embryonic pole at 24 hours. New inclusion bodies appear sequentially: multivesicular bodies at 20 hours, multigranular bodies at 24 hours and lamellar bodies at 30 hours. The functions of these inclusion bodies remain to be studied.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Phase microscopic investigations of Kolmer-fixed, depigmented sections of the adult chicken retina have provided photomicrographic evidence of the existence of three different photoreceptors: single rods, single cones, and double cones. The rod extends the entire thickness of the visual cell layer and is characterized by a uniformly thick outer segment and a hyperboloid-containing inner segment which is devoid of an oil droplet. The single cone is the shortest element; it contains a red oil droplet. The double cone consists of two unequal members, a tall, slender chief cone and a broad accessory cone. The chief component contains a large yellow oil droplet, whereas the accessory cone houses a small, oval, yellowish-green droplet and a characteristically large, oval paraboloid. The rod hyperboloid and the accessory cone paraboloid contain glycogen. No colorless droplets have been observed. Owing to the close association between oil droplet color and cone type, three colored layers of oil droplets are formed within the thickness of the retina: a proximal row of red droplets (the short, single cones), an intermediate layer of yellowish-green droplets (the accessory cones), and a distal row of yellow droplets (the tall chief cones).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 12 (1974), S. 115-130 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Effects of neutralization on butadiene-methacrylic acid copolymers have been studied. In Hycar CTB with 2% acid groups, small-angle x-ray scattering gives evidence of some cation clustering and leads to a value of the mean radius of 5.6 Å for the clusters and a value of the distance between them of 70 Å. When the concentration of salt is increased there is no appreciable change in the distance between clusters or in their size, but their number increases. The structure of clusters has been studied by electron paramagnetic resonance in copolymers neutralized with copper salts. The appearance of a line as in the monohydrated acetate salt permits one to define the structure of clusters consisting of two Cu2+ and four RCOO- ions with two H2O or RCOOH molecules. When the temperature is increased, the signal corresponding to Cu2+-Cu2+ pairs disappears. In high molecular weight butadiene methacrylic acid copolymers with 9% acid groups, we have found the ion pair clusters gathered into larger clusters. In dynamic mechanical properties, a relaxation peak appears at 340°K. We interpret this as due to breaking and possible re-forming of dipolar associations.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 12 (1974), S. 133-140 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The spontaneous imidization of acrylamide during polymerization has been studied in three media: benzene, diglyme, and water. The data indicate that neither medium, time, nor temperatures below 140°C cause imidization to occur. The ascription of the low nitrogen found in polyacrylamide by some investigators to imide formation appears to be in error. The low nitrogen is due rather to retained solvent and/or water, for which polyacrylamide has a strong affinity. Imidization may be brought about by strong acids. The solubility of an imidized polyacrylamide decreases with increasing imide content.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 5 (1967), S. 1289-1296 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: From the conversion-composition data of Gruber and Elias, the reactivity ratios of styrene (M1) and methyl methacrylate (M2) were calculated to be r1 = 0.55 ± 0.02 and r2 = 0.58 ± 0.06 at 90°C. The least-squares method was then used on these and literature values at other temperatures to obtain the Arrhenius expressions: In r1 = 0.04736 - (235.45/T), and ln r2 = 0.1183 - (285.36/T). Using literature values for the homopolymerization steps, A11 = 2.2 × 107l./mole-sec., E11 = 7.8 kcal./mole, and A22 = 0.51 × 107 l./mole-sec.-1, E22 = 6.3 kcal./mole, activation energies and frequency factors were then calculated for the cross-polymerization steps: A12 = 2.1 × 107 l./mole-sec., E12 = 7.3 kcal./mole, and A21 = 0.45 × 107 l./mole-sec., E21 = 5.7 kcal./mole.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Chloromethylbutadiene has been converted to quaternary ammonium and sulfonium monomers which have been polymerized at room temperature. They show a very great tendency to dimerize on heating in water solution. The aqueous quaternary monomer dimerized 25 times as fast as the aqueous sulfonium monomer and nearly 105 times as fast as neat isoprene at 50°C. The quaternary monomer dimerized with itself in a water solution to which 2-hydroxymethylbutadiene has been added as an example of a nonionic diene. The latter monomer did not dimerize rapidly in water, nor did 2-aminomethylbutadiene. The hydrochlorides of 2-aminomethylbutadiene and 2-dimethylaminomethylbutadiene dimerized at rates comparable to that of the sulfonium monomer. Poly 2-chloromethylbutadiene contains reactive chlorine except for the structure resulting from the minor extent of 1,2 addition. Water-soluble derivatives have been made from it with nucleophilic tertiary amines and sulfides. Cationic polymers are substantive to paper pulp, and the sulfonium polymers can be cured in paper to give improved wet strength.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 11 (1973), S. 3037-3042 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It was reported earlier that the copolymerization of acrylamide and styrene is strongly affected by the copolymerization medium. The effect was attributed to a change in the polarity of the ethylenic bond in the acrylamide monomer due to hydrogen bonding and/or dipole - dipole interaction, depending on the medium. In view of those findings, it was suggested that absolute values for the reactivity ratios for the copolymerization of these two monomers might be obtained only when the acrylamide monomer is unperturbed. Copolymerizations of these monomers at a number of ratios, therefore, were done in benzene, which does not undergo hydrogen bonding and has no dipole moment, at high dilution, when amide - amide interactions between acrylamide molecules should be essentially eliminated. The values of r1 and r2(M1 = acrylamide) were 9.14 ± 0.27 and 0.67 ± 0.08, respectively. There appears to be some indication in this system that high dilution adversely affects the reactivity of the acrylamide monomer while enhancing that of styrene. This aspect requires more study.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 4 (1966), S. 2819-2830 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for the determination of reactivity ratios from conversion-composition data has been outlined. The conversion-composition changes during the copolymerization of styrene (M1) and methyl methacrylate (M2) have been studied at 60°C. By a method of graphical intersection, the integrated form of Skeist's equation has been used to determine the reactivity ratios (r1 = 0.54 ± 0.02 and r2 = 0.50 ± 0.06) in reasonably good agreement with values reported in the literature. The area of intersection was used as a measure of the precision of the data.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...