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  • 1975-1979  (20)
  • 1970-1974  (17)
  • 1965-1969  (13)
  • Polymer and Materials Science  (37)
  • Life and Medical Sciences  (12)
  • Avoidance
  • 1
    Electronic Resource
    Electronic Resource
    A controlled comparison of drug effects on escape from conditioned aversive stimulation (“anxiety”) and from continuous shock (1971)
    Springer
    Psychopharmacology 22 (1971), S. 323-332 
    Details
    ISSN: 1432-2072
    Keywords: Chlorpromazine ; Chlordiazepoxide ; Avoidance ; Anxiety ; Escape
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Squirrel monkeys were presented with two stimuli in alternation, separated by time out periods during which neither was present. One was white noise accompanied by irregularly spaced pulses of shock, the other continuous shock at a lower intensity. Following an interval of time which varied in an unpredictable sequence, the next depression of the response lever turned the stimulus off. The schedule on which termination was possible was identical for the two stimuli, and the intensity of the continuous shock was adjusted to a level that produced approximately equal frequencies of pressing, typically from 40 to 80 responses per minute. Doses of chlordiazepoxide ranging from 2.5 to 10.0 mg/kg, i.p., produced a significantly greater decrease in the rate of response in the presence of the continuous shock than in the presence of the noise. On the other hand, doses of chlorpromazine ranging from 0.25 to 1.0 mg/kg, i.p., produced no differential effect. Previous findings of selective action on behavior that terminates signals paired with shock (avoidance) may be related to differences in experimental contingencies or in the pre-drug strength of the two performances compared, rather than to the effect of chlorpromazine on an experimental analogue of human anxiety.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406871
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  • 2
    Electronic Resource
    Electronic Resource
    Noncomplementarity in base sequences between the cohesive ends of coliphages 186 and λ and the formation of interlocked rings between the two DNA's (1967)
    New York : Wiley-Blackwell
    Biopolymers 5 (1967), S. 953-966 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The half molecules of 186 DNA have been isolated by the Hg(II)-Cs2SO4 density gradient centrifugal ion technique. The buoyant densities of the two halves in CsCI at 25°C. are 1.713 and 1.709 g./cm.3, corresponding to GC contents of 54% and 50%, respectively. Similarly, 5-bromouracil labeled λ DNA halves were separated. The isolation of the four DNA halves made it possible to test for homology in base sequences between the cohesive ends of λ and those of 186. There was no indication of any significant homology in base sequences between the cohesive ends of the two DNA's, as indicated by the absence of a band with intermediate buoyant density in CsCI when either half of 186 DNA was annealed with either half of 5-bromouracil labeled λ DNA and then centrifuged. The lack of cohesion between the two DNA's made it possible to demonstrate unequivocally the formation of interlocked rings (catenanes) between the two DNA's. The existence of a dimeric catenane is evidenced by the formation of a species of intermediate buoyant density when 5-bromouracil labeled λ DNA is cyclized in the presence of cyclic 186 DNA of a relatively high concentration. The molecular weight of one DNA relative to the other can be calculated from the position of the dimeric catenane in a density gradient by using the method of Baldwin. The result was in complete agreement with our previous measurements from the sedimentation coefficients and by electron microscopy. The probability of dimeric catenane formation when one DNA is cyclized in the presence of another DNA is discussed. The experimental results agree with the theoretical expectation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1967.360051008
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  • 3
    Electronic Resource
    Electronic Resource
    A re-examination of the cloacal sacs and gland of the blind snake, Leptotyphlops dulcis (Reptilia: Leptotyphlopidae) (1971)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 133 (1971), S. 273-280 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cloacal sacs of Leptotyphlops dulcis are nonglandular, posterior evaginations of the cloaca. The median cloacal gland is tubuloalveolar. Similar unpaired cloacal glands as well as paired sacs are noted in certain colubrid snakes. Terminology applied to these cloacal derivatives is discussed, and a standardization of names is provided.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051330303
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  • 4
    Electronic Resource
    Electronic Resource
    Viscosities of moderately concentrated solutions of polyethylene in ethane, propane, and ethylene (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 117-131 
    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 viscosities of moderately concentrated solutions of low-density polyethylenes in ethane, propane, and ethylene have been measured at low shear rate in the temperature range of 150-250°C and in the pressure range of about 15000-30000 psi. Within the precision of the measurements, the relative viscosity is independent of pressure over the range investigated but increases as the solvent is changed from propane through ethane to ethylene. The activation energy for the relative viscosity in ethane varies from about 0.5 to 2.5 kcal/mole as the concentration changes from 5 to 15 g/dl. Effects of polymer concentration and molecular weight on solution viscosity in ethane at 150°C have been determined, and all of the data can be represented by a single straight-line plot of the logarithm of relative viscosity versus the intrinsic viscosity (in p-xylene at 105°C) times concentration. This simple relation is valid over wide ranges of polymer concentration and molecular weight and over more than two orders of magnitude of relative viscosity. The solution viscosities of the polyethylenes in the three supercritical fluid solvents used appear surprisingly low at first sight. This behavior is partly a result of the low solvent viscosities but also might mean that the polymer has an abnormally low segmental friction factor compared to that in solutions under more familiar conditions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130113
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  • 5
    Electronic Resource
    Electronic Resource
    Poly(vinyl alcohol) hydrogels. Formation by electron beam irradiation of aqueous solutions and subsequent crystallization (1973)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 3779-3794 
    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: Aqueous solutions of poly(vinyl alcohol) were submitted to varying doses of electron beam irradiation. By modification of the classical Flory-Huggins equations appropriate to the initial state of solution of the polymer, the molecular weight between crosslinks, Mc, was calculated as a function of radiation dose, initial polymer concentration, and temperature. Following crosslinking in the solution state, crystallization was induced by dehydrating the network at temperatures above 90°C. Following dehydration, the polymer network was reequilibrated with water and its tensile properties compared with identically prepared hydrogels not subjected to crystallization by dehydration. Greatly enhanced values of ultimate tensile strength and resistance to tear result from the treatment producing crystallization, compared with those of the crosslinked but not previously dehydrated gels.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1973.070171219
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  • 6
    Electronic Resource
    Electronic Resource
    Dynamic mechanical relaxation effects in some poly(arylene sulfones) (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 8 (1970), S. 1169-1175 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly-4,4′-oxydiphenylenesulfonyl and poly-4,4′-methylenediphenylenesulfonyl were synthesized by an electrophilic substitution polymerization of the arylene monosulfonyl chloride monomers. The glass-transition temperatures Tg of these polymers were determined by calorimetric and dynamic mechanical measurements, and the number-average molecular weights were determined by vapor-pressure osmometry. Both polymers were found to have the same Tg at equivalent molecular weight; the limiting value at high molecular weight is 238°C. Both polymers have two dynamic mechanical relaxation peaks at temperatures far below Tg. One is in the neighborhood of 0°C, and the other is at -110°C. Plausible origins for these relaxations, and the absence of any near 0°C in poly(4,4′-isopropylidenediphenylene-co-4,4′-sulfonyldiphenylene dioxide), are discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.160080711
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  • 7
    Electronic Resource
    Electronic Resource
    Interlocked DNA rings. II. Physicochemical studiesThis Work has been supported by a grant GM14621 from the U.S. public Health Service, and a fellowship from the Alfred P. Sloan Foundation. (1970)
    New York : Wiley-Blackwell
    Biopolymers 9 (1970), S. 489-502 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several species of topologically interlocked λb2b5c DNA rings (catenanes) have been prepared in vitro. The sedimentation behavior of dimeric catenanes containing 0, 1, or 2 covalently closed duplex rings has been studied as a function of the superhelical density of the covalently closed ring or rings. In general, if XtpY represents rings X and Y topologically interlocked, the sedimentation coefficient of this species, SXtpY, is related to the sedimentation coefficients SX and SY of the component rings by the empirical relationship SXtpY/SY = [(MX + MY)/MY] [1 + (MX/MY)1.78(SY/SX)1.78]-0.56This equation can also be extended to the case where three monomeric rings are topologically linked in a chain. For two topologically interlocked monomeric rings with neither ring covalently closed, the sedimentation coefficient is 1.35 times that of the monomeric ring. This is different from results reported for mitochondrial and P22 catenanes by others. Several possibilities are discussed to account for this discrepancy. The sedimentation coefficient of a species containing one covalently closed duplex ring and a single-stranded ring was also measured in an alkaline medium. This species, which can be easily derived from a dimeric catenane containing two covalently closed duplex rings, is particularly useful for the identification of covalently closed dimeric catenanes. Some electron microscopic studies of these interlocked rings are presented in an accompanying paper.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1970.360090410
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  • 8
    Electronic Resource
    Electronic Resource
    Optical characterization of orientation of collagen (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 2751-2758 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The optical properties of reconstituted collagen were characterized in the frame-work of a two-phase model. The total birefringence is assumed to be the sum of form birefringence ΔF, of amorphous birefringence Δa, and of crystalline birefringence Δc. The contribution of ΔF has been determined as a function of strain. The intrinsic values of Δc and Δa were calculated to be 0.24 ± 0.06 and 0.055 ± 0.018, respectively. In the undeformed state, the observed birefringence is almost entirely due to the distortion of the electric field of the light at the phase boundary. Whereas there is a slight increase of form birefringence with increasing strain, the total birefringence shows much larger increments. The latter is attributable to orientation of the rodlike superstructures of the tropocollagen molecules.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360121209
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  • 9
    Electronic Resource
    Electronic Resource
    Dynamic mechanical and rheo-optical studies of collagen and gelatin (1972)
    New York : Wiley-Blackwell
    Biopolymers 11 (1972), S. 2015-2031 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The frequency dependence of dynamic mechanical properties of rat tail tendon (RTT), enzyme-solubilized collagen membranes (ESC), AKM-23 dialysis membranes, and gelatin film have been measured at 110, 11, and 3.5 Hz from - 160 to 220°C. RTT and AKM-23 are devoid of a rubbery region; there are as many as six mechanical loss transitions. Gelatin and ESC membranes behave as rubbery materials above room temperature; only three tan δE peaks can be resolved for these materials. Strain birefringence was used to measure the crystalline and amorphous contribution of orientation induced by strain. Both the birefringence and the strain optical coefficient are sensitive to the amount of water in a sample. The effect of chemical swelling agents and of annealing on birefringence are described. Stress relaxation data on gelatin film were analyzed with the rubber elasticity theory to give the average number of chains per unit volume, the specific polarizability, the stress-birefringence ratio and the average molecular weight between hydrogen bonds were calculated. The intrinsic amorphous birefringence for “wet” gelatin film is 1.25 × 10-2; it is estimated to be about 6 × 10-2 for “dry” gelatin film.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1972.360111003
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  • 10
    Electronic Resource
    Electronic Resource
    The effect of ions on the superstructures of reconstituted collagen (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 1063-1069 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of a variety of electrolytes on the stabilization and destabilization of the rod-like superstructures in reconstituted collagen membranes have been studied by small-angle light scattering (SALE). Structural orders at two levels are effected: association-disassociation at the micron level and the helix-coil transitions at the mollecular level. In addition to lyotropic salts, several transition metal ions were also studied. They act to disassociate collagen aggregates by the formation of stable complexes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120510
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