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  • 1
    Electronic Resource
    Electronic Resource
    Solubility of xenon in amino-acid solutions. II. Nine less-soluble amino acids (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 6529-6533 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Ostwald solubility (L) of xenon gas, as the radioisotope 133Xe, has been measured as a function of solute concentration, at 25.0 °C, in aqueous solutions of nine amino acids. The amino-acid concentrations investigated covered much of their solubility ranges in water, viz., asparagine monohydrate (0–0.19 M), cysteine (0–1.16 M), glutamine (0–0.22 M), histidine (0–0.26 M), isoleucine (0–0.19 M), methionine (0–0.22 M), serine (0–0.38 M), threonine (0–1.4 M), and valine (0–0.34 M). We have previously reported solubility results for aqueous solutions of six other, generally more soluble, amino acids (alanine, arginine, glycine, hydroxyproline, lysine, and proline), of sucrose and sodium chloride. In general, L decreases approximately linearly with increasing solute concentration in these solutions. If we postulate that the observed decreases in gas solubility are due to hydration, the results under some assumptions can be used to calculate hydration numbers (H), i.e., the number of H2O molecules associated with each amino-acid solute molecule. The average values of hydration number (H¯) obtained at 25.0 °C are 15.3±1.5 for asparagine, 6.8±0.3 for cysteine, 11.5±1.1 for glutamine, 7.3±0.7 for histidine, 5.9±0.4 for isoleucine, 10.6±0.8 for methionine, 11.2±1.3 for serine, 7.7± 1.0 for threonine, and 6.6±0.6 for valine. We have also measured the temperature dependence of solubility L(T) from 5–40 °C for arginine, glycine, and proline, and obtained hydration numbers H¯(T) in this range. Between 25–40 °C, arginine has an H¯ near zero. This may be evidence for an attractive interaction between xenon and arginine molecules in aqueous solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454438
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  • 2
    Electronic Resource
    Electronic Resource
    Solubility of xenon in amino-acid solutions (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 456-461 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have measured the Ostwald solubility (L) of 133Xe at 25.0 °C in aqueous solutions of the amino acids: alanine (0–1.8 M), arginine (0–0.9 M), glycine (0–2.1 M), hydroxyproline (0–2.3 M), lysine (0–2.8 M), and proline (0–3.5 M) as well as sucrose (0–2.25 M) and NaCl (0–5.25 M). Over the concentration ranges investigated L decreases, monotonically and approximately linearly, with increasing concentration for amino acids and sucrose. The effect on gas solubility of amino acid in solution can be large, e.g., for 133Xe, we measured L(25.0 °C)=0.1060 in distilled water but L(25.0 °C)=0.055 for a 2.8 M lysine solution. The results can be used to calculate hydration numbers (H), i.e., the number of H2O molecules associated with each solute molecule. The average values of hydration number (H¯) obtained at 25.0 °C are 7.9±0.6 for alanine, 0.2±0.5 for arginine, 8.5±0.6 for glycine, 4.5±0.4 for hydroxyproline, 6.1±1.1 for lysine, 2.0±0.2 for proline, and 3.9±0.7 for sucrose.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451623
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  • 3
    Electronic Resource
    Electronic Resource
    Reply to the Comment on: Pressure dependence of the solubility of nitrogen, argon, krypton, and xenon in water (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 96 (1992), S. 3359-3360 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.461936
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  • 4
    Electronic Resource
    Electronic Resource
    Pressure dependence of the solubility of nitrogen, argon, krypton, and xenon in water (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 2724-2735 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Measurements are reported for the pressure dependence of the Ostwald L and mole-fraction x2 solubilities for nitrogen, argon, krypton, and xenon in water at 25.0 °C. The approximate pressure ranges were: N2, 44–116 atm; Ar, 22–101 atm; Kr, 33–81 atm; and Xe, 5–48 atm. Our experimental technique is a modified Van Slyke method which allows the simultaneous determination of L, x2, and partial molar volume v2 of the solute gas in the solvent. For N2, Ar, and Kr we observe deviations from Henry's Law, f2=kHx2 which vary linearly with pressure. For example, the measured values of Henry's constant range from kH (25 °C, 44.6 atm)=90 269 atm to kH (25 °C, 115.8 atm)=100 340 atm for N2 in water. Extrapolation of the data to low pressure yields results for L and x2 which agree with literature values. For Xe we observe a sharp increase in Henry's constant at pressures above 20 atm. The measured partial molar volume also changes sharply from 47 to ∼125 cm3/mol. This is attributed to the observed onset of ice-like clathrates at pressures above 20 atm. The solubility data are analyzed in terms of the Kirkwood–Buff solution theory, and the role of hydrophobic interactions is discussed. For the Kr–water system, we compare the experimental results to recent computer simulations. We also use statistical mechanics arguments to introduce a new solubility parameter which is useful in understanding high-pressure measurements. We conclude by discussing extensions of this work to other gas–liquid systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458911
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  • 5
    Electronic Resource
    Electronic Resource
    Diffusion of xenon in liquid alkanes: Temperature dependence measurements with a new method. Stokes–Einstein and hard sphere theories (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 625-630 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Measurements are reported of the diffusion constant D(T) for xenon gas, in the form of the radioisotope 133Xe, through liquid n-octane, n-decane, and n-tetradecane, in the range 10–40 °C. The values range from D (10.0 °C, Xe→n-C14H30)=1.32×10−5 cm2/s to D (40.0 °C, Xe→n-C8H18)=6.02×10−5 cm2/s. A new experimental method is used in which D is obtained by monitoring the decrease in concentration as gas diffuses into the liquid in an effectively one-dimensional geometry. As expected, the results do not agree with the Stokes–Einstein law. They do follow the usual correlation Dηp=AT, with p=0.708 and A=9.80×10−8, where η is the liquid viscosity in centipoises and T is in K. Application to these results of the rough-hard-sphere theory of diffusion is discussed. A quantitative analysis cannot be made until molecular dynamics results for smooth-hard-sphere diffusion are available.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458413
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  • 6
    Electronic Resource
    Electronic Resource
    Solubility of xenon in perfluoroalkanes: Temperature dependence and thermodynamics (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 517-521 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Measurements are reported of Ostwald solubility (L) and mole fraction solubility (x2) for Xe gas, in the form of the radioisotope 133Xe, in three liquid perfluoroalkanes from 5–25 or 5–50 °C. Results at 25.0 °C are L(133Xe in n-C6F14)=2.11±0.01, L(133Xe in C7F16) =1.95±0.01, and L(133Xe in C8F18)=1.85±0.01. From these data the chemical potentials on the number density scale and mole fraction scale, respectively, Δμ0ρ2 and Δμ02, are calculated as functions of temperature. The corresponding average enthalpy and entropy of solvation, on both scales, are also determined. Results of scaled particle theory and of surface energy theory are compared with experimental thermodynamic quantities. The comparisons are suggestive but better data on solvent properties are needed for a definitive comparison.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.455494
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  • 7
    Electronic Resource
    Electronic Resource
    Solubility of xenon in 45 organic solvents including cycloalkanes, acids, and alkanals: Experiment and theory (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 6569-6579 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: New measurements are reported of the Ostwald solubility L(T), as a function of temperature in the approximate range 10.0–50.0 °C, for 133Xe gas in 13 liquid organic solvents, viz., three cycloalkanes, six carboxylic acids, and four normal alkanals. From our data for each solute–solvent system we determine the mole-fraction solubility x2(T), and the following thermodynamic functions of solution: chemical potential Δμ0ρ2(T)=−RT ln L, enthalpy ΔH¯0ρ2, and entropy ΔS¯0ρ2, where Δμ0ρ2=ΔH¯0ρ2 −TΔS¯0ρ2S¯0ρ2, all based on the number density scale. New results are considered together with previous measurements of xenon solubility in liquid normal alkanes, alkanols, and perfluoroalkanes; in all, data and theory are treated for xenon solubility in 45 organic solvents from six homologous series. The average observed entropy of solvation of Xe is ΔS¯0ρ2=−4.1± 0.5 cal/mol K, remarkably independent of solvent. The results are analyzed with scaled-particle theory from which are obtained hard-core diameters a1, and cavity energies gcav and enthalpies hcav for all the solvents at 25 °C. Values of a1 range from 4.08 A(ring) (for CH3OH) to 9.18 A(ring) (n-C20H42), and gcav ranges from 2520 cal/mol (n-C6F14) to 9430 cal/mol (HCOOH). We discuss the application to solubility in these solvents of interaction site calculations; interaction potentials for the functional groups are available but difficult to apply to these solute–solvent systems. We also discuss the role of configurational entropy, as well as molecular dynamics approaches to calculation of free energies of solubility. Finally the results are examined empirically and values are given for the contribution to chemical potential, enthalpy, and entropy of solvation, of the six functional groups: CH2 (linear molecules), CH3, OH, COOH, CHO, and CH2 (cyclomolecules).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456324
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  • 8
    Electronic Resource
    Electronic Resource
    Sexual differences in cricket calling song recognition (1982)
    Springer
    Journal of comparative physiology 146 (1982), S. 217-221 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Phonotactic behavior was studied in male crickets,Teleogryllus oceanicus. Tethered flying males were presented with electronically synthesized calling song models in a two-choice phonotaxis assay, and their song preferences were determined and compared with previous findings for females. Males are poorer at discriminating between songs than females; they do not display choice behavior as frequently as females, and the choices they do make are not as consistent as those of females (Figs. 3, 4). T. oceanicus calling song is composed of rhythmically different chirp and trill sections. The selectivity of males for these two components differs from that of females. Females prefer chirp to trill, but the opposite is true for males (Fig. 5B-F). Males are similar to females in that they prefer either a conspecific song model or its separate components to a heterospecific model (Fig. 5A, G, H). Behavioral and neural implications of these findings are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00610240
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  • 9
    Electronic Resource
    Electronic Resource
    Proboscis extension in the blowfly: directional responses to stimulation of identified chemosensitive hairs (1987)
    Springer
    Journal of comparative physiology 160 (1987), S. 367-374 
    Details
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We studied the direction of proboscis extension elicited by stimulating each of an identified array of gustatory sensilla, the ‘largest’ hairs, on the labellum of the flyPhormia regina. Individual hairs, or pairs of hairs, were stimulated with sucrose or water and the angle of the ensuing extension of the proboscis was recorded. The direction of the response was graded and depended on the identities of the hairs stimulated. Hairs situated on the anterior region of the labellum elicited anterior extensions, mid-level hairs elicited lateral extensions and posterior hairs resulted in posterior extensions. Previous studies of the labellar hairs have been concerned with their encoding of the chemical nature of the stimulus. Our findings show that each hair also relays information about the location of the stimulus. The positional information provided by these sensilla may help the fly to orient itself with respect to a food source.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00613026
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  • 10
    Electronic Resource
    Electronic Resource
    Calling song recognition in the cricket Teleogryllus oceanicus: comparison of the effects of stimulus intensity and sound spectrum on selectivity for temporal pattern (1993)
    Springer
    Journal of comparative physiology 171 (1993), S. 759-765 
    Details
    ISSN: 1432-1351
    Keywords: Cricket ; Phonotaxis ; Song recognition ; Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of stimulus intensity and stimulus spectrum on tuning for stimulus temporal pattern were compared in crickets (Teleogryllus oceanicus) performing flight phonotaxis. Previous work has shown that tuning became sharper when the intensity of a 5 kHz stimulus was increased. We tested the hypothesis that this sharpening was due to activation of high-frequency tuned, negative phonotactic circuitry, by asking whether adding ultrasound to a 5 kHz stimulus also sharpens tuning. We found that the addition of ultrasound to a 5 kHz stimulus resulted in a slight broadening of the temporal pattern tuning curve. Responses to stimuli composed only of ultrasound are temporal-pattern dependent, and ultrasonic pulses delivered in a pattern similar to the courtship song elicited transient negative phonotactic responses that were followed by sustained positive phonotactic responses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213072
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