The effect of pressure on the radiation-induced conductance of liquid hydrocarbons

1969 ◽  
Vol 47 (6) ◽  
pp. 885-892 ◽  
Author(s):  
D. W. Brazier ◽  
G. R. Freeman
Keyword(s):  
Solid Phase ◽  
The Other ◽  
Electron Localization ◽  
Cavity Model ◽  
Liquid Hydrocarbons ◽  
Appreciable Increase ◽  
Free Ion ◽  
Radiation Induced ◽  
Phase Glass ◽  
Ion Yields

An attempt was made to test the cavity model of electron localization in liquid hydrocarbons by measuring the effect of pressures up to 4000 bars on the radiation induced conductance of n-pentane, n-hexane, n-octane, cyclopentane, methylcyclohexane, and 2,2-dimethylbutane at 30°. Measurements at 3 and 56° were also made on n-hexane and n-octane. The relative induced conductance, i.e. the ratio of the induced conductance at pressure p to that at 1 bar, decreased with increasing pressure. The amount of decrease was slightly greater at low than at high temperatures. The behavior of 2,2-dimethylbutane was complex and is not understood. For the other liquids, it was concluded that the free ion yields remained constant or decreased somewhat with increasing pressure. An appreciable increase in the free ion yields, which is a possible implication of the cavity model of electron localization, did not occur. Therefore, either (a) the cavity model of electron localization in hydrocarbons is wrong, or (b) application of pressures up to 4000 bars did not appreciably alter the cavity concentrations in the liquids. Perhaps the cavity concentration is greatly reduced only by pressures great enough to cause a solid phase (glass or crystal) to form.

Comparison between Molecular Structure Effects in Triplet Positronium Annihilation Rates and Radiolysis Free Ion Yields in Liquid Hydrocarbons

1972 ◽  
Vol 50 (16) ◽  
pp. 2697-2698 ◽  
Author(s):  
G. R. Freeman ◽  
J.-P. Dodelet
Keyword(s):  
Molecular Structure ◽  
Chain Length ◽  
Molecular Interaction ◽  
Half Life ◽  
Density Effect ◽  
Liquid Hydrocarbons ◽  
Positronium Annihilation ◽  
Free Ion ◽  
Alkane Chain ◽  
Ion Yields

Two seemingly unrelated phenomena in liquid hydrocarbons have similar trends in their dependences upon the molecular structure of the hydrocarbon. The phenomena are the annihilation half-life of triplet positronium and the radiolysis free ion yield. In n-alkanes the effect of increasing the molecular chain length, upon both phenomena, appears to be simply to increase the density of interacting sites. Branching the alkane chain decreases the strength of molecular interaction with both electrons and positronium, although the relative decrease is much greater for the former than for the latter. The effects of double bonds on the phenomena, after separating out the density effect, are different from each other.

Oxytocin analogues with non-coded amino acid residues in position 8: [8-Neopentylglycine]oxytocin and [8-cycloleucine]oxytocin

1987 ◽  
Vol 52 (9) ◽  
pp. 2317-2325 ◽  
Author(s):  
Jan Hlaváček ◽  
Jan Pospíšek ◽  
Jiřina Slaninová ◽  
Walter Y. Chan ◽  
Victor J. Hruby
Keyword(s):  
Amino Acid ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
The Other ◽  
Amino Acid Residues ◽  
Phase Synthesis ◽  
Other Hand ◽  
Fragment Condensation

[8-Neopentylglycine]oxytocin (II) and [8-cycloleucine]oxytocin (III) were prepared by a combination of solid-phase synthesis and fragment condensation. Both analogues exhibited decreased uterotonic potency in vitro, each being about 15-30% that of oxytocin. Analogue II also displayed similarly decreased uterotonic potency in vivo and galactogogic potency. On the other hand, analogue III exhibited almost the same potency as oxytocin in the uterotonic assay in vivo and in the galactogogic assay.

Comparison of the Potency of 8-L-Arginine, 8-D-Arginine and 8-D-Homoarginine Vasopressin Analogs with Substituted Phenylalanine in Position 2

1994 ◽  
Vol 59 (6) ◽  
pp. 1439-1450 ◽  
Author(s):  
Miroslava Žertová ◽  
Jiřina Slaninová ◽  
Zdenko Procházka
Keyword(s):  
Amino Acid ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Basic Amino Acid ◽  
The Other ◽  
Side Chain ◽  
Inhibitory Potency ◽  
Phase Synthesis ◽  
Other Hand ◽  
Order Of Magnitude

An analysis of the uterotonic potencies of all analogs having substituted L- or D-tyrosine or -phenylalanine in position 2 and L-arginine, D-arginine or D-homoarginine in position 8 was made. The series of analogs already published was completed by the solid phase synthesis of ten new analogs having L- or D-Phe, L- or D-Phe(2-Et), L- or D-Phe(2,4,6-triMe) or D-Tyr(Me) in position 2 and either L- or D-arginine in position 8. All newly synthesized analogs were found to be uterotonic inhibitors. Deamination increases both the agonistic and antagonistic potency. In the case of phenylalanine analogs the change of configuration from L to D in position 2 enhances the uterotonic inhibition for more than 1 order of magnitude. The L to D change in position 8 enhances the inhibitory potency negligibly. Prolongation of the side chain of the D-basic amino acid in position 8 seems to decrease slightly the inhibitory potency if there is L-substituted amino acid in position 2. On the other hand there is a tendency to the increase of the inhibitory potency if there is D-substituted amino acid in position 2.

scholarly journals Radiation-Induced Asymmetric Grafting of Different Monomers into Base Films to Prepare Novel Bipolar Membranes

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2028
Author(s):  
Shin-ichi Sawada ◽  
Yasunari Maekawa
Keyword(s):  
Acrylic Acid ◽  
Anion Exchange ◽  
Graft Polymerization ◽  
The Other ◽  
Practical Applications ◽  
Bipolar Membranes ◽  
Graft Polymers ◽  
Grafting Reactions ◽  
Radiation Induced

We prepared novel bipolar membranes (BPMs) consisting of cation and anion exchange layers (CEL and AEL) using radiation-induced asymmetric graft polymerization (RIAGP). In this technique, graft polymers containing cation and anion exchange groups were introduced into a base film from each side. To create a clear CEL/AEL boundary, grafting reactions were performed from each surface side using two graft monomer solutions, which are immiscible in each other. Sodium p-styrenesulfonate (SSS) and acrylic acid (AA) in water were co-grafted from one side of the base ethylene-co-tetrafluoroethylene film, and chloromethyl styrene (CMS) in xylene was simultaneously grafted from the other side, and then the CMS units were quaternized to afford a BPM. The distinct SSS + AA- and CMS-grafted layers were formed owing to the immiscibility of hydrophilic SSS + AA and hydrophobic CMS monomer solutions. This is the first BPM with a clear CEL/AEL boundary prepared by RIAGP. However, in this BPM, the CEL was considerably thinner than the AEL, which may be a problem in practical applications. Then, by using different starting times of the first SSS+AA and second CMS grafting reactions, the CEL and AEL thicknesses was found to be controlled in RIAGP.

scholarly journals Syntheses of two deacetyl-thymosin β4analogs and their anti-inflammatory effect on carrageenin-induced edema in the mouse paw

2001 ◽  
Vol 10 (2) ◽  
pp. 89-92 ◽  
Author(s):  
T. Abiko ◽  
R. Ogawa
Keyword(s):  
Marked Reduction ◽  
Solid Phase ◽  
The Other ◽  
Para Position ◽  
Phase Method ◽  
Antiinflammatory Effect ◽  
Solid Phase Method ◽  
Anti Inflammatory ◽  
Inflammatory Effect

Two {Met(0)6}deacetyl-thymosin β4analogs containing Phe(4F) or Tyr(Me) at position 12 were synthesized by the manual solid-phase method, and their anti-inflammatory effect on carrageenin-induced edema in the mouse paw was studied. Fluorination of the para-position of Phe12resulted in a marked antiinflammatory effect on carrageenin-induced edema in the mouse paw compared with that of our synthetic {Met(0)6}deacetyl-thymosin β4, but the other analog, {Met(0)6, Tyr(Me)12}deacetyl-thymosin β4, showed a marked reduction of the anti-inflammatory effect.

Low energy electron ranges in liquids: determination by nonhomogeneous kinetics

1977 ◽  
Vol 55 (11) ◽  
pp. 2050-2062 ◽  
Author(s):  
J.-P. Dodelet
Keyword(s):  
Critical Temperature ◽  
Melting Point ◽  
Distribution Functions ◽  
Liquid Density ◽  
Range Distribution ◽  
Total Ionization ◽  
Free Ion ◽  
Drastic Increase ◽  
Pass Through ◽  
Ion Yields

Free ion yields have been measured in four hydrocarbon liquids: n-pentane, cyclopentane, neopentane, and neohexane. Each liquid has been studied from room temperature or below up to the critical temperature. Theoretical curves have been calculated using the relation between the free ion yields and the external field strength derived by Terlecki and Fiutak on the basis of an equation by Onsager. Two popular electron range distribution functions, Gaussian and exponential, have been shown not to be an adequate representation of the reality as far as the model used for the calculations is concerned. In order to fit experimental points, both range distribution functions would require a drastic increase in the total ionization yield, Gtot, with temperature increase. This would mean an unrealistic decrease of the ionization potential of the molecule from the melting point up to the critical temperature.It is possible to keep Gtot quite constant and within the range of values obtained by other techniques by extending the Gaussian range distribution function with a (range)−3 probability tail. The most probable range can be normalized for the liquid density. This parameter has been used to obtain information about the behaviour of epithermal electrons in the four alkane liquids from the melting point up to the critical temperature.(1) Normalized penetration ranges of epithermal electrons are dependent on the structure of the molecule in the entire liquid range but differences are smaller at critical than at low temperatures.(2) Normalized penetration ranges of epithermal electrons pass through a maximum in the liquid phase for neopentane, neohexane, and cyclopentane. No maximum is observed for n-pentane.(3) There is no drastic change in the behaviour of epithermal electrons in these alkanes at the critical temperature.

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