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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 16 (1987), S. 985-997 
    ISSN: 1572-8927
    Keywords: Aqueous solution ; cell constant ; conductance ; electrolytic conductivity ; potassium chloride ; primary ; resistance ; resistivity, secondary, standards, and temperature scale
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Measurements of aqueous electrolytic conductance are performed routinely in a variety of disciplines and industries. Conductivity is a measure of the ionic content in solution and thus has applications in pharmaceuticals, power plants, rainwater, lake surveys, and oceanography, to name a few. A thorough review of the measurement of and standards for aqueous electrolytic conductance is herein presented. At present, the most precise and accurate standards have been set forth by the International Organization of Legal Metrology (OIML), and have been adopted by most other standards organizations. However, the uncertainty assigned to these standards, especially the secondary standards, is somewhat larger than would be expected from the physical aspects of the measurement. Several changes in the units and measurement scales, including temperature, volume, molar mass, resistance, and concentration obfuscate the accuracy of these standards. In addition to the review, research is proposed, using a conductance cell with variable length, to establish new standards for aqueous electrolytic conductance.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 18 (1989), S. 515-528 
    ISSN: 1572-8927
    Keywords: Absolute standard ; conductivity cell ; demal ; electrolyte ; molality ; potassium chloride ; primary standard ; specific conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A determination of the absolute specific conductance of KCl solutions is demonstrated. The measurement is based on the conductance cell with a well defined geometry, having a difference in the removable center tube of accurately measured dimensions. The specific conductance of the solution is obtained from the measured resistances of the cell with and without the center tube and the measured l/A ratio of the center tube. Specific conductances obtained using the cell agree with the previously accepted standards for 0.1 demal and 0.01 demal solutions within 0.02%. Results are also presented for solutions based on molality. The temperature control, bridge, and detector technology used to obtain results of this accuracy are described.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 20 (1991), S. 391-401 
    ISSN: 1572-8927
    Keywords: Cell constant ; conductance ; demal ; electrolytic conductivity ; potassium chloride ; primary standards ; resistance ; specific conductance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An absolute determination of aqueous electrolytic conductivity has been made for primary standards 0.01D and 0.1D (demal) potassium chloride solutions over the temperature range of 0 to 50°C in 5 degree intervals. A cell with a removable center section of accurately known length and area was used for the measurements. Values were adjusted to be in conformity with the ITS-90 temperature scale. The overall uncertainty over the entire temperature range is estimated to be 0.03%. Values at 25°C for 0.01D and 0.1D KCl solutions are 0.0014086 and 0.012852 S-cm−1, respectively.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Excised mouse pubic bone rudiments were exposed to H3-thymidine. Rudiments preserved immediately after exposure consisted of mesenchyme with a large number of cells showing intense radioactivity. Rudiments incubated on a filter membrane after exposure went through the developmental stages of complete chondrification of the pubic rami followed by periosteal and then endochondral bone formation. Only chondrocytes showed radioactivity in rami consisting of cartilage and periosteal bone that were preserved prior to endochondral ossification. Cell types showing radioactivity in rami preserved during endochondral ossification were chondrocytes, chondroclasts, and osteoblasts and osteocytes of endochondral bone. The results of the study demonstrated that hypertrophic chondrocytes of the calcified cartilage of a developing mammalian long bone not only survive dissolution of their matrix, but transform into chondroclasts and osteoprogenitor cells that give rise to osteoblasts and osteocytes which form endochondral bone in the absence of blood vessels.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Typical immature pubic joints developed when undifferentiated mesenchyme from the pelvic region of 13-day-old embryos was grown in vitro on a Millipore filter. After five days the joints were transplanted to 5-day-old postnatal female mice whose pubic joints were excised prior to transplantation. The transplanted joints developed to adult-type symphyses and replaced the excised joints of the recipients. Typical bone resorption and cartilage transformation to ligamentous tissue occurred in transplanted joints in pregnant recipients.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0197-8462
    Keywords: abnormalities ; chick embryos ; pulsed magnetic fields ; development ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Six independent experiments of common design were performed in laboratories in Canada, Spain, Sweden, and the United States of America. Fertilized eggs of domestic chickens were incubated as controls or in a pulsed magnetic field (PMF); embryos were then examined for developmental anomalies. Identical equipment in each laboratory consisted of two incubators, each containing a Helmholtz coil and electronic devices to develop, control, and monitor the pulsed field and to monitor temperature, relative humidity, and vibrations. A unipolar, pulsed, magnetic field (500-μs pulse duration, 100 pulses per s, 1-μT peak density, and 2-μs rise and fall time) was applied to experimental eggs during 48 h of incubation. In each laboratory, ten eggs were simultaneously sham exposed in a control incubator (pulse generator not activated) while the PMF was applied to ten eggs in the other incubator. The procedure was repeated ten times in each laboratory, and incubators were alternately used as a control device or as an active source of the PMF. After a 48-h exposure, the eggs were evaluated for fertility. All embryos were then assayed in the blind for development, morphology, and stage of maturity. In five of six laboratories, more exposed embryos exhibited structural anomalies than did controls, although putatively significant differences were observed in only two laboratories (two-tailed Ps of .03 and 〈.001), and the significance of the difference in a third laboratory was only marginal (two-tailed P = .08). When the data from all six laboratories are pooled, the difference in incidence of abnormalities in PMF-exposed embryos (∼25 percent) and that of controls ( ∼ 19 percent) although small, is highly significant, as is the interaction between incidence of abnormalities and laboratory site (both Ps 〈 .001). The factor or factors responsible for the marked variability of inter-laboratory differences are unknown.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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