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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Space science reviews 1 (1963), S. 589-611 
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Conclusions Since all the models referred to above reproduce observations of zodiacal light, but vary considerably in their composition, it is clear that the ambiguities must be resolved if we are to achieve a reliable description of interplanetary matter. For such purpose we must acquire additional information on the following aspects of the problem: a) Scattering functions of non-spherical particles, studied either by optical or microwave experiments using particles in form and refractive index similar to the micrometeorites collected by sounding rockets. b) Brightness and polarization of zodiacal light obtained by sounding rockets and satellites. All ground measurements are disturbed by terrestrial airglow, but this difficulty will be overcome by measurements made from altitudes 〉 150 km. In addition to their greater reliability in representing zodiacal light, such observations will provide data within the regions of elongation between the corona and 20° and from 90° to 180°, as et almost unobserved. Any marked deviation of the observations from the prediction by the models referred to above would have importance for further study. c) Particle counts and electron density measurements by deep space probes. Although space probes can provide only samples, results will be significant for obtaining a better estimate of both numbers of electrons and the presence of small particles in interplanetary space. Especially must we determine whether there is only a cloud of small particles around the earth (Whipple, 1961b) or whether the submicron particles, as collected by Soberman et al., are spread out over a major region of the solar system. Such a solution would justify the application of Type III models. On the basis of the information outlined above, we might possibly find by optical methods models which, combined with our knowledge of the particulate content of space derived from meteorites and mechanical considerations (see Whipple, 1962a), would greatly enhance our understanding of the interplanetary media Such models might be similar to Type III but with a spatial variation in particle size and density distribution which also takes into consideration the properties of the Corona. It must be emphasized, however, that the present measurements and analyses do not warrant reliable conclusions about the electron density.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Physics and chemistry of minerals 17 (1991), S. 611-616 
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The components of the interfacial surface tension of talc and pyrophyllite were determined by measuring the rate of the capillary rise of a number of liquids through thin, sedimented deposits of the powdered minerals. The rate of capillary rise of a liquid in a powder is related to the contact angle between the liquid and the solid by the Washburn equation. The contact angles thus derived were used to determine the apolar (Lifshitzvan der Waals) component, γ LW , and the polar, electronacceptor and electron-donor parameters, γ ⊕ and γ ⊖ respectively, of the Lewis acid/base component of the total interfacial surface energy using the Young equation. The values of γ LW for talc and pyrophyllite (31.5 and 34.4 mJ/m2) are slightly smaller than for smectite clay minerals (e.g., the value for hectorite is 39.9 mJ/m2), the electron donor parameter values are roughly comparable for talc and pyrophyllite (γ ⊕ = 2.4 and 1.7 mJ/m2) as are the values of the electron acceptor parameter (γ ⊖ = 2.7 and 3.2 mJ/m2). The well-known hydrophobicity of these two minerals is due to the remarkably small value (for silicate minerals) of γ ⊖(γ⊕ is normally small or zero for silicates and many other oxides). The small values of both γ ⊕ and γ ⊖ mean that the Lewis acid/base interactions between talc or pyrophyllite and highly polar water molecules are very weak. In contrast, low-charge smectites, the minerals most similar chemically and structurally to talc and pyrophyllite, have much greater values of γ ⊖ (≥ 30 mJ/m2) and are hydrophyllic.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 15 (1972), S. 401-403 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Corrected values of the efficiency factorQ pr of light pressure are presented for spherical particles of graphite and metallic materials.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 307 (1981), S. 127-128 
    ISSN: 1618-2650
    Keywords: Best. von Wasser in Kieselgel ; Röntgenfluorescenz-Spektrometrie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Publication Date: 2013-04-20
    Description: Air quality is a primary environmental concern in highly industrialised areas, with potential health effects in children residing nearby. The Sarroch industrial estate in Cagliari province, Sardinia Island, Italy, hosts the world’s largest power plant and the second largest European oil refinery and petrochemical park. This industrial estate produces a complex mixture of air pollutants, including benzene, heavy metals and polycyclic aromatic hydrocarbons. Thus, we conducted a cross-sectional study to evaluate the prevalence of malondialdehyde–deoxyguanosine adducts in the nasal epithelium of 75 representative children, aged 6–14 years, attending primary and secondary schools in Sarroch in comparison with 73 rural controls. Additionally, the levels of bulky DNA adducts were analysed in a subset of 62 study children. DNA damage was measured by 32 P-postlabelling methodologies. The air concentrations of benzene and ethyl benzene were measured in the school gardens of Sarroch and a rural village by diffusive samplers. Outdoor measurements were also performed in other Sarroch areas and in the proximity of the industrial estate. The outdoor levels of benzene and ethyl benzene were significantly higher in the school gardens of Sarroch than in the rural village. Higher concentrations were also found in other Sarroch areas and in the vicinity of the industrial park. The mean levels of malondialdehyde–deoxyguanosine adducts per 10 8 normal nucleotides ± standard error (SE) were 74.6±9.1 and 34.1±4.4 in the children from Sarroch and the rural village, respectively. The mean ratio was 2.53, 95% confidence interval (CI): 1.71–2.89, P 〈 0.001, versus rural controls. Similarly, the levels of bulky DNA adducts per 10 8 normal nucleotides ± SE were 2.9±0.4 and 1.6±0.2 in the schoolchildren from Sarroch and the rural village, respectively. The means ratio was 1.90, 95% CI: 1.25–2.89, P = 0.003 versus rural controls. Our study indicates that children residing near the industrial estate have a significant increment of DNA damage.
    Print ISSN: 0267-8357
    Electronic ISSN: 1464-3804
    Topics: Biology , Medicine
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  • 7
    Publication Date: 2015-06-17
    Description: Chronic silica exposure has been associated to cancer and silicosis. Furthermore, the induction of oxidative stress and the generation of reactive oxygen species have been indicated to play a main role in the carcinogenicity of respirable silica. Therefore, we conducted a cross-sectional study to evaluate the prevalence of 3-(2-deoxy-β-D-erythro-pentafuranosyl)pyrimido[1,2-α]purin-10(3H)-one deoxyguanosine (M 1 dG) adducts, a biomarker of oxidative stress and peroxidation of lipids, in the nasal epithelium of 135 silica-exposed workers, employed in pottery, ceramic and marble manufacturing plants as well as in a stone quarry, in respect to 118 controls living in Tuscany region, Italy. The M 1 dG generation was measured by the 32 P-postlabelling assay. Significant higher levels of M 1 dG adducts per 10 8 normal nucleotides were observed in the nasal epithelium of smokers, 77.9±9.8 (SE), and in those of former smokers, 80.7±9.7 (SE), as compared to non-smokers, 57.1±6.2 (SE), P = 0.001 and P = 0.004, respectively. Significant increments of M 1 dG adducts were found in the nasal epithelium of workers that handle artificial marble conglomerates, 184±36.4 (SE), and in those of quarry workers, 120±34.7 (SE), with respect to controls, 50.6±2.7 (SE), P = 0.014 and P 〈 0.001, respectively. Null increments were observed in association with the pottery and the ceramic factories. After stratification for different exposures, silica-exposed workers that were co-exposed to organic solvents, and welding and exhaust fumes have significantly higher M 1 dG levels, 90.4±13.4 (SE), P = 0.014 vs. control. Our data suggested that silica exposure might be associated with genotoxicity in the nasal epithelial cells of silica-exposed workers that handle of artificial marble conglomerates and quarry workers. Importantly, we observed that co-exposures to other respiratory carcinogens may have contributed to enhance the burden of M 1 dG adducts in the nasal epithelium of silica-exposed workers.
    Print ISSN: 0267-8357
    Electronic ISSN: 1464-3804
    Topics: Biology , Medicine
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