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An equivalent noise conductivity Λn for aqueous uni-univalent electrolytes is defined on the basis of the Langevin equation. Apparatus for the recording of noise spectra and their evaluation by means of correlation methods are described. It is shown that Λn of NaCl and of KCl solutions parallels that obtained by conventional bridge methods though no external electric field as applied in the case of noise measurements. Λn for both these electrolytes is shown to obey the Debye—Hueckel—Onsager limiting law in its concentration dependence and to exhibit the usual Arrhenius form of temperature dependence. The activation energy obtained is close to that obtained from conventional bridge methods applying an external field, and closely approximates that of the viscosity of the solvent, viz. water. The noise generated by the electrolyte is shown to be white noise, being independent of frequency without any 1/f frequency component being present. There is no contact noise.

We have studied the electrical conductivity of NaDNA solutions under “saltfree” conditions at temperatures well below the melting point of DNA, using radio-frequency dielectric and noise measurements. A conductivity discontinuity is observed at a temperature well below that at which the usual denaturation processes and trans conformation may commence. The radio-frequency permittivity also exhibits a discontinuity at the same temperature. For the premelting phase, the conductivity versus temperature curves consist of two linear regions with a change in slope occurring at 23°C. This effect is related to the behavior of the ionic sheath covering the DNA macromolecule. The activation energy of the alternative current conductivity as well as that the equivalent noise conductivity results as 3.11 kcal/mole below and 4.08 kcal/mole.

The conformational analysis by the Extended Huckel Theory of the deoxyribose-phosphate unit in the principal configurations of the sugar is discussed. The work is divided into three parts in order to determine the role of the different elements constituting such a unit. (1) The simultaneous study, for the four principal configurations of the sugar, of the possible ranges of the rotational parameters ψ and ϕ′ with P3 and P5 without their oxygen atoms. (2) The study of the influence of the oxygen atoms, situated on P3 and P5, on the rotations ψ and ϕ′ for the C3′endo and C2′endo sugar configurations. (3) The study of the influence of a nucleobase on the rotation ψ, and whether the oxygen atoms of the phosphate groups should be taken into account or not. The results show the equivalences C3′endo ≃ C2′exo and C2′endo ≃ C3′exo; that the allowed angular ranges of our rotational parameters depend, in some degree on the chosen sugar configuration; and that the rotations ψ and ϕ′ appear as “quasi” independent. In addition, an energetic classification which, according to the Extended Huckel Theory, seems to show that the C2′endo sugar configuration is the most favored for our unit was established; it was shown that the introduction of the oxygen atoms has no influence on the rotation ψ, but on the contrary leads to a restriction of the possible range for the ϕ′ parameter; and it was determined that the influence of the adenine base fixed in its position of minimal energy (i.e., anti-conformation) on the rotation ψ, as a function of the presence or absence of the oxygen atoms, is relatively limited.

The sodium and chloride activity coefficients in DNA solution were measured by selective electrodes. These experiments were performed for native and thermally denatured DNA. The ratio of activities in helix and coil states were compared with those given by Manning's model. These results are in good agreement with the theoretical values. We also compare the experimental values of the charge parameter XXX of DNA in the helix (XXX h ) and coil (XXX c ) configurations with the theoretical parameters appearing in Manning's model and which have been adjusted to correspond with the known conformation of the molecule. From this comparison, we deduce the change of enthalpy (Δ H ) T m at the temperature of denaturation ( T m ) of DNA. The value of (Δ H ) T m thus calculated is smaller than the theorstical value and comparable with that observed experimentally by Privalov et al.

Nach einigen Betrachtungen uber die Konstruktion der Hochtemperatur-Gas-Chromatographie wird eine neuentwickelte Apparatur beschrieben, die ohne Anschlus an ein Vakuum und mit Wasserstoff als Tragergas arbeitet; sie vermag bei guter Trennung hochmolekulare Paraffine sowie Methylester der naturlichen und der synthetischen Fettsauren bis zu ca. 26 Kohlenstoffatomen im Molekul wie auch deren Folgeprodukte (Fettalkohole, Amine, Nitrile usw.) in relativ kurzer Zeit zu analysieren. Gas-Chromatographic Analysis of High Molecular Weight Fat Derivatives without the Use of Vacuum After some considerations over the construction of high-temperature-gas-chromatography, a newly developed apparatus has been described, that works without the application of vacuum and with hydrogen as carrier gas. It is capable of good separation of high molecular paraffins as well as methylester of natural and synthetic fatty acids up to 26 carbon atoms in the molecule as also their related products (fatty alcohols, amines, nitriles, etc.) in relatively shorter time to analyse.

A dielectric method is presented to measure the ejection of counterion during the thermal fusion of Na DNA solutions. The dielectric conductivity behavior at fixed frequency versus temperature is a measure of the molar concentration of counterfoils formed from the macromolecules. A linear dependence between Na+ cations released and DNA concentration was verified. We consider the variation of sodium activity coefficient Δ during thermal transconformation to be in good agreement with other experimental data.

A convenient method for preparing 2,6-dimethylpyrylium hexachloroantimonate (IIIa) and the first synthesis of the corresponding perchlorate (IIIb) are reported. The chloroantunonate (IIIa) undergoes HD exchange in deuteroacetic acid. The reactivity sequence is, as in other cases α-methyls > β-hydrogens (γ-hydrogens do not exchange); however, the reactivity difference is smaller than in other cases. A mechanism involving the nucleophilic solvent attack on the γ-position is suggested for the exchange of β-hydrogens. The salt IIIa abstracts a hydride ion from phenyl-substituted 1,5-diketones, to give phenyl-substituted pyrylium salts. This reaction also takes place with pyrylium salts other than III, thus enabling to compare the relative stabilities of these compounds.

Starting from the easily available 2,4,6-tri-d3-methylpyrylium perchlorate, the following methyl-deuterated compounds were prepared : 1,3-dimethylnaphthalene III, nitromesitylene IV, mesidine V, mesitylenediazonium hydrogen sulphate VI, mesitylene VII, mesitol VIII and I-mesityleneazo-2-naphthol IX. Their infrared spectra and deuterium analyses show that some dedeuteration occurs during the reaction of pyrylium salts. A new naphthalene synthesis from benzylmagnesium chloride and 1,3-diketones is reported.