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  • Wiley-Blackwell  (22)
  • American Association for the Advancement of Science  (17)
  • 1980-1984  (23)
  • 1965-1969  (16)
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Year
  • 11
    Electronic Resource
    Electronic Resource
    Transmembrane potential and intracellular potassium ion activity in fetal and maternal liver (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 121 (1984), S. 7-12 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have compared transmembrane potentials (Em) of maternal liver with Em of fetal liver, and as an initial step to account for differences in Em, we have measured intracellular potassium ion activities (aik) in both tissues. Paired segments of maternal and fetal (day 17) mouse liver were suffused (15 ml/min) with Krebs' physiologic salt solution equilibrated with 95% 02 -5% CO2 (pH 7.3-7.4) at 37°C. To measure Em, cells were impaled with open-tip microelectrodes filled with 0.5 M KCI. Intracellular voltage recordings that were stable ± 2 mV for at least 10 s were considered valid impalements. Maternal liver mean Em = - 41 ± 1 (SEM) mV, n = 10 animals. In contrast, fetal liver mean Em = - 23 ± 1 (SEM) mV, n = 10 animals. In the same segments we measured aik with potassium-selective liquid ion-exchanger microelectrodes. Maternal liver mean aik = 95 ± 7 (SEM) mM and fetal liver mean aik = 62 ± 4 (SEM) mM. In addition, Em and aik of fetal liver increased to values comparable to those of maternal liver during the first 8 days of neonatal life. The differences of Em and aik between fetal and maternal liver, and the changes in these values that occur in the neonate, may result from activity of a membrane Na-K exchange pump that increases with tissue development.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041210103
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  • 12
    Electronic Resource
    Electronic Resource
    X-ray production in thin films by electrons with energies between 40 and 100 keV. 1 - Bremsstrahlung cross-sections (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 12 (1983), S. 153-162 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Cross-sections for bremsstrahlung production in thin films may be derived theoretically only if certain approximations are made or if there is recourse to numerical techniques. In this paper, two approximate equations, one based on the Sommerfeld theory and the other on the Bethe-Heitler theory, are assessed for their accuracy in predicting cross-sections differential in photon energy and emergence angle when a thin foil target is bombarded with electrons with energies between 40 and 100 keV. Experimental data are presented from eight different target materials and these are processed initially to make comparisons between experimental and theoretical spectral shapes and subsequently to compare observed and predicted absolute cross-section values. Except for the heaviest target material (Au), the Bethe-Heitler theory provided a satisfactory description of all experimental observations. In contrast, the Sommerfeld theory provided a significantly inferior description of spectral shapes and consistently overestimated absolute cross-sections by 15-20%.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300120407
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  • 13
    Electronic Resource
    Electronic Resource
    The sodium and potassium activated ATPase of intestinal epithelium. I. Location of enzymatic activity in the cellThis study is based on work performed under contract with the United States Atomic Energy Commission at The University of Rochester Atomic Energy Project, Rochester, New York. (1965)
    Philadelphia : Wiley-Blackwell
    Journal of Cellular and Comparative Physiology 65 (1965), S. 361-372 
    Details
    ISSN: 0095-9898
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The location of sodium and potassium activated Mg-ATPase (Na-K ATPase) was studied in columnar epithelial cells of the small intestine of rats. Cell components were segregated in centrifuge fractions by a mild procedure (sucrose medium), which preserved mitochondria and vesicular inclusions, and by a drastic procedure, designed to preserve the striated borders selectively. The contents of fractions were characterized by phase contrast and electron microscopy and by the assay of alkaline phosphatase (E.C.3.1.3.1), cytochome oxidase (E.C.1.9.3.1), invertase (E.C.3.2.1.26) and Mg-ATPase (E.C.3.6.1.4).Na-K ATPase was found to be most concentrated in fractions containing mitochondria on one hand, and striated borders on the other. Its distribution differed from the distributions of the other four enzymes. The physiological implications of finding the “sodium pump” enzyme in the membrane at the apical pole of the epithelial cell were discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1030650309
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  • 14
    Electronic Resource
    Electronic Resource
    A comparative dielectric study of human serum low density lipoprotein before and after partial digestion by trypsin (1980)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 13 (1980), S. 47-52 
    Details
    ISSN: 0091-7419
    Keywords: lipoprotein ; trypsin ; dielectric measurements ; counterions ; α-dispersion ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: The relative permittivity of aqueous solutions of human serum low density lipoprotein (LDL) and partially trypsin digested lipoprotein (T-LDL) has been determined for various concentrations at 20°C over the frequency range 0.15-100 MHz. Comparison of the dielectric dispersion curves for the digested lipoprotein with those for the native preparation revealed a larger low-frequency dielectric increment, which may be attributed to an increase in the number of counterions moving over the surface of the molecule. An explanation of this observation is an elevation of 70% in the net negative charge on the surface of the trypsin-treated particle as compared to its native counterpart.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400130105
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  • 15
    Electronic Resource
    Electronic Resource
    X-ray production in thin films by electrons with energies between 40 and 100 keV. 2For Part l. see p. 153. - Characteristic cross-sections and the overall x-ray spectrum (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    X-Ray Spectrometry 12 (1983), S. 163-169 
    Details
    ISSN: 0049-8246
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Two approximate theories are considered for the production of characteristic x-rays when thin foil targets are bombarded with electrons with energies between 40 and 100 keV. One, due to Kolbenstvedt, is semi-classical in nature whilst the other, due to Bethe, contains two parameters which are normally adjusted empirically. Data from six different target materials are presented, but because errors in experimentally derived absolute cross-sections are large, a comparison is made between theoretical and observed ratios of characteristic Kα photons to bremsstrahlung photons in a 20 eV channel directly beneath the peak. By adjusting the Bethe parameters and using a modified Bethe-Heitler theory to predict the bremsstrahlung, agreement between experiment and theory of typically 10% is recorded. Finally, a means of simplifying the equations used to enable rapid calculation of x-ray spectra with a pocket calculator is indicated.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/xrs.1300120408
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  • 16
    Electronic Resource
    Electronic Resource
    Vinyl polymerization in the presence of copper salts (1980)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 827-850 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radical polymerization of several vinyl monomers has been studied in the presence of cupric chloride. A termination reaction with CuII species leads to the formation of CuI species which can also participate significantly in termination with some, but not all, of the monomers studied. A theoretical treatment of the kinetics of such systems is presented which takes full account of initiator depletion during extended inhibition during extended inhibition periods. Specific velocity constants for reactions of polymer radicals with both CuII and CuI moieties are derived from observations on the nonstationary phase at the end of the inhibition period and from the subsequent steady state of polymerization. On the basis of the results presented here, together with the work of other authors, the patterns-of-reactivity approach gives α = -5.4, β = 9.0 as the parameters for copper (II) chloride. The implications of the results in relation to the mechanisms of the reactions between polymer radicals and both copper(II) chloride and copper(I) chloride are discussed. The kinetic treatment also provides an improved method for the determination of the rate of initiator decomposition and the rate of initiation form studies of the inhibition period.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1980.170180305
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  • 17
    Electronic Resource
    Electronic Resource
    A study of the spectra of diacetylenic phospholipid polymers in solvents and dispersions (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 513-520 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phospholipids, of which phosphoryl cholines are a specific example, are the most common lipid components of cell membranes. Synthetic acetylenic phospholipids form closed model membranes, vesicles, or liposomes when dispersed in water. Below the temperature at which lipid chain crystallization occurs irradiation of vesicles causes polymerization of the diacetylene groups. In chloroform solution the spectrum of the polymer is independent of temperature. However, when the polymer is dissolved in methanol or dispersed in water with another lipid spectral changes occur. As solution or dispersion is cooled a second peak appears on the long wavelength side of the original absorption and gradually increases in intensity. Evidence that suggests that this peak is associated with aggregated polymer chains is presented. It appears that within the aggregates exciton coupling splits the excited state into two new levels and only transitions to the level of lowest energy are allowed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.170200224
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  • 18
    Electronic Resource
    Electronic Resource
    Application of a high accuracy finite difference technique to steady, free surface flow problems (1983)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 3 (1983), S. 583-590 
    Details
    ISSN: 0271-2091
    Keywords: QUICK ; Finite Difference ; Free Surface Flow ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The spatially third-order accurate QUICK finite difference technique is applied to the solution of the depth-integrated equations of motion for steady, subcritical, free surface flow in a wide, shallow, rectangular channel with and without an abrupt expansion. The conservative, control-volume discretization of the equations of motion and the use of QUICK in approximating required cell and cell face average quantities is discussed. Results presented show that it is possible to obtain stable solutions for advective free surface flows without resorting to implicit numerical smoothing.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fld.1650030605
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  • 19
    Electronic Resource
    Electronic Resource
    The expression of β-galactosidase during preimplantation mouse embryogenesis (1981)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 1-12 
    Details
    ISSN: 0192-253X
    Keywords: β-galactosidase ; preimplantation ; mouse ; Bgl ; paternal effect ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Lysosomal acid hydrolase expression during preimplantation mouse embryogenesis has proved useful in estimating when mRNA transcription commences during this period. Previous work from this laboratory has shown that α-galactosidase and β-glucuronidase undergo 50- to 100-fold increases in activity between the two-cell stage and the blastocyst stage [1, 2]. Here we show that β-galactosidase activity levels undergo a similar change. We also demonstrate that mouse strains with the Bgl-sh allele produce cleavage stage embryos with 2-4-fold higher activity levels than strains with the Bgl-sd allele. Bgl has been shown to control β-galactosidase levels in adult mouse tissues [3]. Unfertilized egg β-galactosidase levels are also regulated by Bgl, but loci distant from Bgl modify egg expression. The distant sites are not observed to act during cleavage. Hybrid embryos (Bgl-sd/h) show intermediate activity levels to the parental types. The timing of the deviation of hybrid embryo β-galactosidase activity levels from maternal-type activity levels is used to estimate when transcription of genes governing β-galactosidase expression occurs.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020020102
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  • 20
    Electronic Resource
    Electronic Resource
    Homogeneous ionic copolymerization. A study of solvent effects in the styrene systemsThis is the 22nd in a series of papers concerned with ionic polymerizations; for the previous paper in this series, see Overberger and Kamath.1 (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 2865-2875 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of solvent in the homogeneous anionic copolymerization of styrene with p-methylstyrene, p-tert-butylstyrene, and m-methylstyrene has been determined. In nonpolar media where the gegenion is lithium, a nonhomogeneous distribution exists with the more basic monomer in higher concentration at the growing chain end which shows as an enhanced relative reactivity. This is depressed by the addition of a small amount of more polar solvent. The influence of temperature as a function of solvent has been determined for selected anionic systems. In nonpolar media, an increase of temperature favors incorporation of the less basic monomer whereas a more polar solvent has only a small effect and favors a more ideal copolymerization. In cationic copolymerization the effect of hyperconjugation has been demonstrated. This effect of hyperconjugation appears to be enhanced in polar media. The cationic copolymerizations of styrene with p-tert-butylstyrene in nitrobenzene shows a steric hindrance of the bulkier monomer on its incorporation into the copolymer. Determination of reactivity ratios as defined for radical systems does not fully characterize ionic copolymerizations.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030813
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