Netsu Sokutei

Calorimetric Analysis of the Effect of ⁶⁰Co γ-rays on the Growth of Saccharomyces cerevisiae

Sandra Wirkner, Katsutada Takahashi, Masakazu Furuta, Toshio Hayashi

2001 Volume 28 Issue 3 Pages 106-113
Published: June 15, 2001
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.28.106

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Using a heat conduction type multiplex calorimeter equipped with 24 calorimetric units the heat evolution from growing ⁶⁰Co γ-irradiated Saccharomyces cerevisiae was detected in the form of growth thermograms. ⁶⁰Co γ-irradiation affected the growth pattern in which a dose-dependent reduction of the growth rate constant was obsereved together with the retardation in growth, indicating an involvement of bactericidal and bacteriostatic effects. These effects were quantitatively analyzed in terms of the bactericidality as a function of dose intensity, which was defined in the previous paper.
It was shown that the bactericidal effect of γ-ray irradiation was dominant within lower doses and decreased almost linearly with the increasing doses up to 3kGy. An equation to determine the number of survivors on the basis of the parameters calorimetrically determined was developed. The survival rate obtained by a proposed equation was in good agreement with that determined from the colony counting up to a dose range of 4kGy. However, a remarkable difference was found to exist between the two results obtained at doses higher than 4kGy. The discrepancy was discussed in terms of action mechanism of irradiation.

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Electronic Heat Capacity of Organic Superconductor κ-(BEDT-TTF)₂Cu[N(CN)₂]Br

Quasi-particles Excitations and Anisotropy in Energy Gap

Yasuhiro Nakazawa

2001 Volume 28 Issue 3 Pages 114-122
Published: June 15, 2001
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.28.114

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The low-temperature heat capacity of single crystals of κ-(BEDT-TTF)₂Cu[N(CN)₂]Br was studied by the thermal relaxation technique in the temperature range between 0.11K and 4.2K. By analyzing temperature dependence data of electronic heat capacity C_el, we can see a quadratic term due to the quasiparticle excitations over the superconductive gap exists at low-temperature region below 2K. The recovery rate of electronic heat capacity coefficient γ is found to obey square root of external magnetic fields H. These results demonstrate that the superconductivity of this material is an unconventional one with line-nodes in the superconductive gap.

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Complex Formation of Large-ring Cyclodextrins with Iodine in Aqueous Solution as Revealed by Isothermal Titration Calorimetry

Shinichi Kitamura, Kazuya Nakatani

2001 Volume 28 Issue 3 Pages 123-128
Published: June 15, 2001
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.28.123

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Complex formation of large-ring cyclodextrins (CDs) having DP21-32 with iodine in aqueous KI solution was studied by isothermal titration calorimetry (ITC). When the individual CD is shown, the term CD_n is used, where n represents the degree of polymerization. For CDs in the DP range of 21-32, the curves obtained for the titration of the CDs with iodine can be analyzed by a model assuming 1:2 complex formation with identical interacting sites. For the case of two identical interacting sites, the binding constants K₁ and K₂ (K₁ < K₂), defined relative to the progress of saturation, lie in the range 0.7 to 7.3×10³M^-1 and 3.0 to 62.6×10³M^-1, respectively. The values of ΔH₂ and TΔS₂ lie in the range -34.9 to -136.4kJ mol^-1 and -15.5 to -112.8kJ mol^-1, respectively. The largest values for -TΔS₂ obtained for a CD₂₆ can, in part, be attributed to a large decrease in conformational flexibility of the CD which occurs during complex formation. Based on ITC data, conformational changes in CD₂₆ which are induced as the results of the formation of a CD-iodine inclusion complex are discussed in terms of the recently reported crystal structure of CD₂₆.

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Thermodynamic Investigation of Interaction between Ca Cation and Negatively Charged Phospholipid Bilayers as Studied by DSC and Isothermal Titration Calorimetry

Michiko Kodama, Hiroyuki Aoki, Kazuyuki Hirata, Yuuji Tsutida

2001 Volume 28 Issue 3 Pages 129-134
Published: June 15, 2001
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.28.129

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The interaction of a negatively charged vesicle composed of dimyristoylphosphatidylglycerol (DMPG) and Ca²⁺ was investigated by isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC). A schematic diagram of relative enthalpy (ΔH) versus temperature (t) was constructed from two types of calorimetric enthalpies obtained by ITC and DSC and was compared for the fully neutralized vesicle (Ca²⁺-binding vesicle) and the charged vesicle (Ca²⁺-free vesicle). It was found that the stabilization enthalpy of the DMPG vesicle due to a binding of Ca²⁺ is larger for the liquid crystal phase than for the gel phase, so that the transition enthalpy of the gel-to-liquid crystal phase, i. e., the enthalpy difference between the two phases, is smaller for the Ca²⁺-binding vesicle than for its free vesicle although the transition temperature is higher for the former than for the latter.

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Nonaqueous Solution Coordination Chemistry Studied by Titration Calorimetry

Shin-ichi Ishiguro, Morito Komiya

2001 Volume 28 Issue 3 Pages 135-143
Published: June 15, 2001
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.28.135

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Titration calorimetry is a powerful tool for determining thermodynamic parameters of metal-ion complexation in non-aqueous solvents. By using this method, we could have simultaneously obtained formation constants and enthalpies of not only binary but also ternary metal complexes. The enthalpy and entropy values of metal-ion complexation reflect the change in the solvation number, and thus provide useful information on the coordination structure of metal complexes in solution. In non-aqueous solvent, unlike water, solvent-solvent interaction (solvent structure) in the bulk liquid is generally weak, and solvation steric effect operates upon coordination of bulky solvent molecules to the metal ion. This leads to an enhanced complexation of anionic ligands such as halide ions, even in an aprotic donor solvent that has a stronger donor property than water. Here, the results on the formation thermodynamics and structure of metal-ion complexes will be discussed from the view-point of solvation steric effect.

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Titration Calorimetry of Nonionic Surfactant Solutions

Akio Ohta, Norihiro Ikeda, Makoto Aratono

2001 Volume 28 Issue 3 Pages 144-151
Published: June 15, 2001
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.28.144

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The thermodynamic equations developed by us for analyzing titration calorimetry of surfactant solutions were summarized and applied to the following cases: titration by pure surfactant liquid, aqueous solution of a surfactant, and that of a binary surfactant mixture. The partial molar enthalpy accompanied by dissolutions of surfactants into water and that by micelle formation were evaluated by using the derivative of the enthalpy of mixing with respect to the surfactant concentration. The phase diagram of micelle formation was used for estimating the partial molar enthalpy changes of micelle formation of a surfactant mixture.

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Titration Calorimetry of Binary Solutions

Takayoshi Kimura

2001 Volume 28 Issue 3 Pages 152-155
Published: June 15, 2001
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.28.152

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With the aim of understanding the mechanisms of molecular discrimination and molecular behaviors of biological and biomimic systems on the bases of intermolecular interactions and conformations of stereo specific molecules, various kinds of thermodynamic measurements have been developed with the developments of experimental tools and apparatus by us on a line of policy to increase precision and accuracy and of downsizing the amounts of samples required. A titration calorimetry of binary mixtures give direct results of partial molar enthalpy to know the structure of solution and necessary a relatively small amount of samples to determined whole range of concentration. By the use of a titration calorimeter, we recently engaged in the measurements of heat of mixing of each pair of enantiomers of liquid state.

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phlogiston

2001 Volume 28 Issue 3 Pages 156-157
Published: June 15, 2001
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.28.156

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Application to the Various Fields of the Multiple Points Type Calorimeter

Kenji Tsutsumi, Hiroshi Sato, Seiichi Hagiwara

2001 Volume 28 Issue 3 Pages 158-159
Published: June 15, 2001
Released on J-STAGE: September 07, 2009

DOIhttps://doi.org/10.11311/jscta1974.28.158

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