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Volume 16 (1989)
- Issue 4 Pages 165-
- Issue 3 Pages 101-
- Issue 2 Pages 49-
- Issue 1 Pages 2-
Volume 16, Issue 3
Displaying 1-7 of 7 articles from this issue
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Norikazu Komada1989 Volume 16 Issue 3 Pages 101-111
Published: July 30, 1989
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSA new phonon-density distribution model was developed. It is composed of five parts corresponding to transverse acoustical, longitudinal acoustical, transverse optical, longitudinal optical, and internal vibrational modes. The model takes account of influence of atomic mass distribution and non-spherical shape of the first Brillouin zone upon the phonon-density distribution. An isometric molar lattice heat-capacity formula was derived on the basis of the new phonon-density distribution model under the harmonic oscillator approximation. Though the formula contains several parameters to be evaluated, a single parameter, θKW, is remained after simple and easy evaluation of the other parameters from chemical and crystallographic data of each particular compound. θKW is similar to the Debye's characteristic temperature in several respects. Three computer codes named LEM-1, -2, and -3 were prepared for its convenient use since the formula requires extremely cumbersome calculation to be evaluated. The new formula as well as the Debye one was compared with experimental low-temperature heat-capacity curves of five scapolite samples to prove its validity.View full abstractDownload PDF (1557K) -
On n-Alkane CrystalsKanichiro Takamizawa1989 Volume 16 Issue 3 Pages 112-121
Published: July 30, 1989
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSIn order to obtain a comprehensive understanding of polyethylene crystals, n-alkanes have been examined as model compounds. It has become apparent that the phase transition and related thermal behavior of n-alkane samples have remarkably been affected by the existence of homologues. At first, it is described on the crystalline structure of low molecular weight polyethylene fractions formed in dilute solution. By the presence of molecular weight distribution in the fractions, bicomponent crystals were obtained; one was extended-chain crystal, the other was once folded-chain crystal. Thermal analysis was proved to be useful in characterization of the bicomponent crystals. In order to get a precise information of chain folding phenomena, it was necessary to prepare the monodisperse samples having exact molecular weights corresponding to n-alkanes, although it was difficult to synthesize pure and long n-alkanes. It has been known that folded-chain crystals exhibit thickening when they are maintained at a temperature below their melting point. It was suggested that this phenomena seemed to correlate to solid-solid transitions of higher n-alkane crystals. The high temperature phase showed a gradual structural changes during heating process by X-ray measurement, although it was difficult to discern the change on DSC curves. Transition temperatures and entropies of pure odd n-alkanes from heneicosane to tritetracontane are given as a function of carbon number per molecules.View full abstractDownload PDF (1467K) -
Kenji Kamide, Masatoshi Saito1989 Volume 16 Issue 3 Pages 122-133
Published: July 30, 1989
Released on J-STAGE: September 07, 2009
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Yoshimi Maeda1989 Volume 16 Issue 3 Pages 134-146
Published: July 30, 1989
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSDifferential scanning calorimetry (DSC) of several plasmid DNAs was carried out. The DSC curves for the DNAs linearized with a restriction enzyme provided several peaks due to the stepwise transition of double-stranded DNA to single-stranded DNA along the molecular chain. These DSC curves are very similar to the melting profiles constructed by calculation from the entire base sequences of these plasmids according to the helix-coil transition theory. The theoretical analysis shows that the boundaries of cooperative melting regions of the DNA coincide with the end regions of each of the coding regions. The interaction between various drugs and plasmid DNA was also studied by the DSC method. The DSC curves of DNA in the presence of drugs are affected in the characteristic manner depending upon the interaction mode of the drug, demonstrating that DSC method is very useful for the study of the drug-DNA interaction.View full abstractDownload PDF (1882K) -
Toshiharu Takizawa1989 Volume 16 Issue 3 Pages 147-156
Published: July 30, 1989
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSSome recent topics concerning to the structure and properties of lipid bilayers are reviewed with the special reference to hydrophobic hydration. The partial molar heat capacity per CH2 group in the aqueous dispersions of phospholipids is much larger than the heat capacity per CH2 group in solid paraffins. The reason for the large heat capacity is well interpreted by hydrophobic hydration of CH2 groups within the phospholipid bilayers. The mixing enthalpies of the aqueous dispersions of triphosphoinositide (TPI) and the aqueous CaCl2 solution are positive, while those of glycerylphosphoryl-inositoldiphosphate (GPIDP, the hydrophilic part in TPI) are negative at lower concejtrations of CaCl2. The positive contribution of the hydrocarbon chains in TPI to the mixing enthalpy is attributed to the dehydration of lipid bilayers induced by Ca2+ ions. The water adsorption experiment shows that the amount of hydrophobic hydration of the unsaturated acyl chains in the lipid bilayers is much higher than that of the saturated chains.View full abstractDownload PDF (1595K) -
H. Yoshida, N. Kanno, K. Nanbu1989 Volume 16 Issue 3 Pages 157-159
Published: July 30, 1989
Released on J-STAGE: September 07, 2009
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T. Okino, Y. Kidaka1989 Volume 16 Issue 3 Pages 160-162
Published: July 30, 1989
Released on J-STAGE: September 07, 2009
JOURNAL FREE ACCESSDownload PDF (366K)
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