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  • 1
    Electronic Resource
    Electronic Resource
    A Consistent Approach to Tabulation of Evaluated Solubility Data: Application to the Binary Systems RbCl-H2O and UO2(NO3)2-H2O (1995)
    s.l. : American Chemical Society
    Journal of chemical information and modeling 35 (1995), S. 675-696 
    Details
    ISSN: 1520-5142
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ci00026a003
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  • 2
    Electronic Resource
    Electronic Resource
    Relative risk of colorectal cancer after cholecystectomy (1988)
    Springer
    International journal of colorectal disease 3 (1988), S. 215-218 
    Details
    ISSN: 1432-1262
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The relative risk of developing colorectal cancer after cholecystectomy was assessed retrospectively in 493 patients with colorectal cancer (239 women, 254 men). The results were compared with a control group of patients matched for sex and age. The overall relative risk was 0.7 (90% confidence interval, 0.7–0.8). However, when the data were analysed for site significant differences were seen. In the caecum and ascending colon the relative risk of developing colorectal cancer after cholecystectomy was 2.8 (90% confidence interval, 1.0–9.4). In the rectum the relative risk was only 0.3 (90% confidence interval, 0.2–0.6) in both sexes. The results suggest a relative increased risk of developing right-sided colon cancer after cholecystectomy in women. However, they only partially support the hypothesis that prior cholecystectomy increases the relative risk of developing colorectal cancer in view of the data relating to the the rectum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01660717
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  • 3
    Electronic Resource
    Electronic Resource
    Complexation of Li+, Na+ and K+ Ions by [222], [222D], [221], [221D] Cryptands in Acetonitrile at 25 °C: Conductometric Determination of the True Thermodynamic Formation Constants (1999)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 35 (1999), S. 451-465 
    Details
    ISSN: 1573-1111
    Keywords: conductivity ; ion–cryptand complexes ; thermodynamic formation constants in acetonitrile ; lithium ; sodium and potassium perchlorates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new method is presented for the analysis of precise conductance data to obtain the true thermodynamic formation constants of macrocyclic–cation complexes. The method, based on the Lee–Wheaton theory on mixed electrolytes, takes into consideration the ion pair formation of both the uncomplexed and complexed cations and avoids the use of the simple additivity assumption of the conductances of two electrolytic species present in salt/ligand/solvent systems. The method has been applied to determine the thermodynamic complexation constants of lithium, sodium and potassium ions with the cryptands [221], [222] and their decyl derivatives [221D], [222D] in acetonitrile. The results show that the presence of an alkyl chain in the molecular structure of the cryptands decreases the macrocyclic–cation complexation constant with respect to the values obtained for the parent compounds by almost an order of magnitude. Such a finding has been explained in terms of the asymmetric position in the space of the oxyethylenic bridges of the macrocyclic ligand promoted by the presence of the linked hydrocarbon chain. The above explanation has been confirmed by the anomalous behavior of both the ion-pair association constants of complexed salts and their limiting molar conductivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008053018475
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  • 4
    Electronic Resource
    Electronic Resource
    Measurements ofn−p correlations in the reaction of relativistic neon with uranium (1986)
    Springer
    The European physical journal 323 (1986), S. 391-398 
    Details
    ISSN: 1434-601X
    Keywords: 25.70.Np
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report a preliminary measurement of coincident neutron-proton pairs emitted at 45° in the interaction of 400, 530, and 650 MeV/A neon beams incident on uranium. Charged particles were identified by time of flight and momentum, as determined in a magnetic spectrometer. Neutral particles were detected using a thick plastic scintillator, and their time of flight was measured between an entrance scintillator, triggered by a charged particle, and the neutron detector. The scatter plots and contour plots of neutron momentum vs. proton momentum appear to show a slight correlation ridge above an uncorrelated background. The projections of this plane on then-p momentum difference axis are essentially flat, showing a one standard deviation enhancement for each of the three beams energies. At each beam energy, the calculated momentum correlation function for the neutron-proton pairs is enhanced near zero neutron-proton momentum difference by approximately one standard deviation over the expected value for no correlation. This enhancement is expected to occur as a consequence of the attractive final state interaction between the neutron and proton (i.e., virtual or “singlet” deuterons). The implications of these measurements are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01313520
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  • 5
    Electronic Resource
    Electronic Resource
    Conductivities of KF and CsF in methanol at 25°C (1996)
    Springer
    Journal of solution chemistry 25 (1996), S. 541-553 
    Details
    ISSN: 1572-8927
    Keywords: Potassium ; cesium ; fluoride ; halide ions and perchlorate ; methanol ; water ; molar conductivities ; ion association ; Gibbs energies of transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Electrolytic conductivities of KF and CsF in methanol solution have been determined at 25°C. The single ion molar conductivities of the fluoride ion, obtained from the two salts are in excellent agreement and indicate that the F− ion is highly solvated in methanol (MeOH). Combination of the present and literature data for related salts in both water and MeOH indicate that while the primary solvation of ions may be more extensive in H2O there is considerable enhancement of the secondary solvation sheath in MeOH. Recalculation of high precision literature conductivity data using a consistent mathematical approach indicates that ion pair formation constants for simple 1:1 electrolytes in MeOH are 1 or 2 orders of magnitude greater than in H2O. This is shown to be entirely due to the less favorable solvation of ions in MeOH, as the Gibbs energies of transfer of the neutral ion pairs MX from H2O to MeOH are also unfavorable. Calculations also show that ion association in MeOH is strongly influenced by coulombic interactions whereas in H2O short range interactions are generally more important.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00973084
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  • 6
    Electronic Resource
    Electronic Resource
    Conductance and ion association in dimethylsulfite (1986)
    Springer
    Journal of solution chemistry 15 (1986), S. 663-673 
    Details
    ISSN: 1572-8927
    Keywords: Conductivities ; Ion association ; 1∶1 electrolytes ; acetone ; dimethylsulfite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The electrolytic conductances of LiClO4, LiAsF6, NaClO4 and the n-butylammonium salts Bu4NCl, Bu4NClO4, and Bu4NBPh4 (tetraphenylborate) have been determined in dimethylsufite at 25°C. Ion association constants calculated from these data are interpreted in terms of solvent-separated ion pairs (for LiClO4, LiAsF6, and NaClO4), and contact ion pairs (for the n-butyl-ammonium salts). Comparisons are made for analogous electrolytes in acetone, and in which all salts form contact ion pairs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00644598
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  • 7
    Electronic Resource
    Electronic Resource
    Conductance of 1:1 electrolytes in methyl formate (1987)
    Springer
    Journal of solution chemistry 16 (1987), S. 225-235 
    Details
    ISSN: 1572-8927
    Keywords: Conductivities ; 1:1 electrolytes ; methyl formate ; ion pairs ; triple ions ; ion solvation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The electrolytic conductivities of LiClO4, LiAlCl4, LiAsF6, NaClO4, NaBPh4, and Bu4NClO4 have been measured in methyl formate at 25°C. Evidence is presented for strong association between the perchlorate ion and the formyl proton of the solvent. Ion association and triple ion formation constants suggest that LiClO4, LiAlCl4, and NaClO4 form solvent separate ion pairs and triple ions. NaBPh4 forms contact ion pairs and triple ions, and the remaining salts appear to form both types of ion pairs and triple ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00646988
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  • 8
    Electronic Resource
    Electronic Resource
    Conductance of 1∶1 electrolytes in methyl acetate (1989)
    Springer
    Journal of solution chemistry 18 (1989), S. 977-991 
    Details
    ISSN: 1572-8927
    Keywords: Conductivity ; 1∶1 electrolytes ; methyl acetate ; ion pairs ; triple ions ; ion solvation ; activity coefficients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The electrolytic conductances of NaClO4, NaB(C6H5)4, (n-C4H9)4NClO4 and (n-C4H9)4NPF6 have been measured in methyl acetate at 25°C. A dominating feature of these electrolyte solutions is, as expected, strong ion pairing. In addition it is found that the formation of triple ions makes an important contribution to the overall molar conductivities. The data suggest that there are strong ion-solvent interactions leading to structure-enhanced (after Diamond) ion association and triple ion formation which has an exact analogy in the phenomena of salting-in. The effects of increasing solution permittivity and viscosity are discussed, particularly in regard to comparing two models of treating conductivity data. The first model includes ion pairs and triple ions, and the second model ignores triple ion formation ascribing the anomalous increase in molar conductivities to a decrease in the ion association equilibrium constant caused by increasing solution permittivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00647897
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  • 9
    Electronic Resource
    Electronic Resource
    Complexation of alkali metal cations by calix[4]Arene-bis-crown-6 in methanol, acetonitrile and propylene carbonate (1996)
    Springer
    Journal of solution chemistry 25 (1996), S. 955-970 
    Details
    ISSN: 1572-8927
    Keywords: Electrolytic conductance ; molar conductance ; ion pair formation ; complex formation ; 18-crown-6 ; calix[4]arene-bis-crown-6 ; lithium perchlorate ; sodium perchlorate ; potassium perchlorate ; rubidium perchlorate ; cesium perchlorate ; acetonitrile ; methanol ; propylene carbonate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Résumé The interactions of Li+, Na+, K+, Rb+, and Cs+ with the “double-crown calix,” calix[4]arene-bis-crown-6, have been studied in methanol, acetonitrile, and propylene carbonate at 25°C using precise conductivity measurements. For Li+ and Na+ in solutions containing this calix[4]arene, only 1:1 cation:ligand complexes are formed which permit the determination of the thermodynamic complexation formation constants,K f. The conductivity data strongly suggest that 2:1 cationcalixarene complexes form with K+, Rb+, and Cs+. The existence of 2:1 complexes was experimentally confirmed for the potassium systems by a mass spectroscopic method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00972592
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  • 10
    Electronic Resource
    Electronic Resource
    Thermodynamics of saturated lanthanide nitrate-water systems (1985)
    Springer
    Journal of solution chemistry 14 (1985), S. 473-484 
    Details
    ISSN: 1572-8927
    Keywords: Lanthanide nitrates ; hydrates ; solubilities ; activities ; solvation energies ; phase transitions ; congruent melting points ; specific solvation ; metastable equilibria ; tetrad effect ; double-double effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The thermodynamic properties of saturated aqueous lanthanide nitrate solutions were determined using recently published critically evaluated solubility and activity data. The variation of the thermodynamic functions and congruent melting points as a function of atomic number are interpreted in terms of changes in inner sphere coordination number in both the solid hexahydrates and in the aquo ions, and in terms of the double-double effect. Inconsistencies in experimental solubility data are generally caused by uncertainties in solid phase composition which is shown to be due to the very small Gibbs energies accompanying transitions from stable to metastable systems differing in the number of hydrating water molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00646979
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