Practical usefulness of sample controlled rate thermal analysis (SCTA) and kinetic deconvolution analysis for simultaneous overlapped thermal decomposition processes of inorganic solids and polymer were reviewed. The principle and techniques of SCTA, especially controlled rate evolved gas analysis- thermogravimetry (CREGA-TG), was compared with conventional measurements. A physico-geometrical kinetic interpretation is described based on the results of a kinetic study using TG and the microscopic observation of the reaction process. As exemplified by successful kinetic approaches to the thermal decomposition process, the applicability and the usefulness of kinetic deconvolution are discussed. It was concluded that kinetic deconvolution serves as a tool to characterize the simultaneously overlapping kinetic processes of thermal decomposition of inorganic solids and polymers, as long as the overlapping reaction processes are kinetically independent.

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When researchers design specific ligands to regulate target proteins in cellular regulation or drug discovery, they usually focus on a higher affinity of ligands. Consequently, ligands having lower affinities are frequently removed in the ligand selections. However, these selections do not necessarily explain the mechanism of inhibitory actions of ligands. Therefore, we have doubt that the high affinity selection is always equal to the specificity selection. Since the specific ligands possess a specific binding manner in the protein-ligand interactions, we focus on the biophysical quality, especially thermodynamics, of ligand interactions but not high affinity to obtain the specific ligands against the target proteins. Thermodynamic analysis using Isothermal Titration Calorimetry (ITC) is one of the representative biophysical methods, since it can monitor the direct binding of compounds with thermal reaction and discuss the binding specificity. We are studying some ligand screenings for target enzymes, for example, we obtained one hit small molecule to inhibit the target using biophysical methods including thermodynamic analysis. This ligand successfully inhibits the target protein in cells, although its binding affinity is around μM range. Therefore, we propose that the important factor governing the ligands' specificities is not only high affinity but also the thermodynamics.

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Analysis methods are discussed for polymer crystallization and melting with three different types of plots constructed by using fast-scan calorimetry and small angle X-ray scattering for the determination of the melting point T_M, heat of fusion ΔH_f and crystalline lamellar thickness d_c. Two of those plots are the well-known Hoffman-Weeks plot of T_M against crystallization temperature T_c and the Gibbs-Thomson (G-T) plot of T_M against 1⁄d_c in terms of the data-sets obtained in the primary stage of polymer crystallization. The third plot is a newly proposed Thermal G-T plot of T_M against 1/ΔH_f, both of which shows a logarithmic time evolution in the secondary stage with reorganization,i.e. lamellar thickening and crystal perfecting, of existing crystals formed in the primary stage. By utilizing those plots, the zero-entropy-production melting point T_M⁰, folding surface free energy σ_e, and a thickening coefficient γ can be evaluated. Obtained results are self-consistent and agreed with prior literature values. Temperature dependent σ_e suggests curved melting and crystallization lines of the G-T plot. Application of fast heating is essential for the quantitative analysis of the melting behavior of chain-folded lamellar crystals in a metastable state.

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Antibody affinity maturation plays an essential role during an immune response, resulting in the generation of highly matured antibodies. It is well known that the antigen-binding mechanism varies during the maturation process. The well-shaped form for antigen-binding is often favored in matured antibodies and enables them to bind to antigens with high affinity. However, molecular insight into the correlation between antigen-binding and affinity maturation is limited. This information could be useful for the elucidation of an immunological response. It has been previously shown that at least two antibody types are secreted after immunization with (4-hydroxy-3-nitrophenyl)acetyl (NP). One of the antibody types appeared during an early stage of the immune response, while the second type appeared at a late stage of immunization. A key residue of these antibodies is located at position 95 on the heavy chain; the former type has Tyr (Tyr^H95-type) and the latter type has Gly (Gly^H95-type). Although Fv domains of these antibodies were encoded by the same genes present on variable heavy and light chains, Gly^H95-type antibodies have ~10-100 fold higher binding affinity to NP than those of Tyr^H95-type antibodies. We examined the biophysical properties of single-chain Fvs (scFvs) of Tyr^H95- and Gly^H95-type antibodies. Antigen-binding and thermal stabilities of scFvs were evaluated using isothermal titration calorimetry and differential scanning calorimetry, respectively. Thermodynamic analysis enabled us to discuss affinity maturation and adaptive dynamic nature of the immune response.

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Single-molecule magnets (SMMs) are materials showing magnetic bistability at the molecular level. This review provides a fundamental concept of the SMMs by reviewing the slow magnetic relaxations and the quantum tunneling of the magnetization (QTM) of a Mn12 cluster and lanthanoid(III)-phthalocyaninato double-decker complexes. In the latter part, the enhancement of the SMM properties utilizing the various kinds of dimerization method is reviewed. The dimerization by connecting the two double-decker SMMs with Cd(II) ions revealed that very weak SMM-SMM interactions could suppress the QTM. Covalently linked SMM dimer showed larger magnetic hysteresis than monomer complex did, indicating that magnetic properties were enhanced by the ferromagnetic SMM-SMM interactions. Finally, the supramolecular interactions in the solution were utilized for dimerization. The magnetic relaxation time (τ) of the supramolecular dimer became 1000 times larger than that of the monomer, showing the effectiveness of the dimerization for enhancing SMM properties.

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Catechins, which are polyphenols contained in tea leaves, are an important ingredient in tea beverages. (−)-Epigallocatechin gallate (EGCg) is the most abundant catechins in tea leaves. It is known that inclusion of EGCg with cyclodextrins (CDs) reduces the astringency and bitterness of EGCg. To elucidate the formation mechanism of the inclusion complex between EGCg and βCD (EGCg-βCD), the study using isothermal titration calorimetry (ITC), ¹H-NMR spectroscopy and molecular modeling calculation (MMC) was performed. It was found that two types of EGCg-βCD are formed in an aqueous solution depending on the pH of the solution. The first type of the complex with a large association constant was formed independently of the pH of the solution. In the complex, the A-ring of EGCg was inserted deeply into the cavity of βCD. On the other hand, the second type of complex, the G–ring of EGCg was included in the βCD's cavity, was formed depending on the pH of the solution. Furthermore, the intermolecular hydrogen bonds formed between EGCg and βCD were found to be important for complex formation. These results suggested that when determining the structures of inclusion complexes in an aqueous solution, ITC might be indispensable to discuss the inclusion mechanism between cyclodextrin and guest molecules such as catechins with some insertable sites.

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