Yoshimasa Ishihara

DYNAMICS OF HYDRATION OF ALCOHOLS AND DIOLS IN AQUEOUS SOLUTIONS

The 17 O NMR spin–lattice relaxation times, T 1 , of the solvent water in aqueous solutions of nine alcohols and five diols have been determined as a function of the concentration at 25°C. For the alcohol solutions, the concentration dependence of T 1 has been determined in the temperature range from 1 to 50°C. The value of n h [(τ c h / τ c 0 )-1] which has been obtained from the concentration dependence of T 1 has been defined as the dynamic hydration number (n DHN ). The values of the coordination numbers n h , have been estimated on the basis of the water-accessible surface areas (ASA) of the solute molecules. The rotational correlation times, τ c h , of water molecules around the solute molecules have been estimated and compared with that of pure water τ c 0 . The value of τ c h /τ c 0 =2.22 for Bu t OH at 25°C is the largest among the solutes investigated. The τ c h /τ c 0 values of the n-alcohols and diols increase with increasing ASA and become almost constant. The τ c h /τ c 0 values decrease with increasing temperature and approach constant value above 40°C. The temperature dependence of τ c h /τ c 0 for Bu t OH is the largest. The activation energy of τ c h for n-alcohols has the maximum value at ASA≈240 A 2 . These results are discussed by considering the molecular sizes. The τ c h /τ c 0 value for a diol was smaller than that of the corresponding n-alcohol. This result supports the concept that hydrophobic hydration is distributed by the OH groups of the solute molecules. The thermodynamic properties of hydration for n-alcohols, butanol isomers and diols are linearly dependent on their n DHN .

Hydration of amines, diamines, polyamines and amides studied by NMR

The spin–lattice relaxation times, T1, of natural abundance H217O have been measured for aqueous solutions of nine amines, five diamines, two polyamines and five amides, as a function of the concentration at 25 °C. The water-accessible surface areas of the solute molecules were calculated. The coordination number, nh, and the rotational correlation times, τhc, of water molecules around the solute molecules were estimated and compared with that of pure water τ0c. The value of τhc/τ0c= 2.02 for tert-butylamine is the largest and that of τhc/τ0c= 0.97 for urea the smallest obtained. The value of nh(τhc/τ0c– 1) was defined as the dynamic hydration number (DHN).The partial molar volumes and the partial molar heat capacities for these homologues at infinite dilution are linearly dependent on their DHN.

Progressive increase in minimum proton exchange rate with maturation of liquor

Abstract Proton exchange rate measurement was carried out by 17O-NMR spectroscopy using mother liquors of malt (aged for 0 to 15 years) and grain (aged for 0 to 8 years) whiskies, and of shochu (aged for 1 to 21 years) and awamori(aged for 0 to 10 years) of Japanese traditional spirituous liquor, and commercially available whiskies (aged for 5 to 21 years) and brandies (aged for 5 to 45 years). Through the examination of proton exchange rate based on 17O-NMR half width - pH curve plots, it has been found that the minimum proton exchange rate increases as the period of maturation of liquor becomes longer.

Proton nuclear magnetic resonance spectroscopy of urine for rapid multicomponent analysis of intraoperative cellular metabolites

We serially measured the proton nuclear magnetic resonance spectra of the urine of intraoperative patients over time to assess their potential use for rapid multicomponent analysis of cellular metabolites. Within a few minutes, the spectra provided signals of many low molecular weight urinary metabolites, including amino acids, ketone bodies, lactate, and glucose. The proton magnetic resonance spectra of the urine of most of the intraoperative patients showed large increases in urinary excretion of alanine, ketone bodies, and lactate and/or glucose, confirming alterations in energy substrate-endocrine relationships during the perioperative period. These metabolic changes appeared to be roughly proportional to the degree of surgical stress, but they were not consistent among patients who underwent the same operation. The study suggests that routine intraoperative metabolic monitoring is necessary to prevent critical metabolic disorders and that proton nuclear magnetic resonance spectroscopy of urine may meet this need by allowing rapid multicomponent analysis of cellular metabolites.

Calorimetric Evaluation of Antifungal Activity of TBZ.

カビの発育熱を熱量計で測定し,その発育熱の変化から,TBZのA.nigerに対する抗カビ活性を検討した.サーモグラムと形態観察により,カビの発熱はカビの形態変化の過程で,菌糸の成長,すなわち細胞増殖による代謝熱であることが示された.さらに,この発熱は培地に添加したTBZの濃度が高くなるにつれて,時間的に遅れることを認めた.その遅れ時間をTAKAHASHIらのバクテリア増殖抑制モデルに適用して解析を行ったところ,カビの発育速度が1/2になるTBZ濃度[I]1/2,さらに最小発育防止濃度MICを定量的に決定することができた.本法により求めたMIC値は従来法によるMIC値と良く一致しており,本法の有効性が確認された.