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  • Author or Editor: K. Matsumoto x
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Summary Thermogravimetry (TG) and Me2CO adsorption measurements for flexible porous crystalline coordination polymers with 2-dimensional (2-D) frameworks, {[Co(NCS)2(3-pia)2]·4Me2CO}n (1⊃4Me2CO, 3-pia=N-(3-pyridyl)isonicotinamide), were carried out. Taking advantages of capability of hydrogen bonding of amide groups for a dynamic properties, 1⊃4Me2CO show crystal (non-porous)-to-crystal (porous) structural rearrangement in Me2CO adsorption/desorption processes. The activation energy for the Me2CO desorption process of 1⊃4Me2CO was obtained using Flynn-Wall-Ozawa’s (FWO) method. The Me2CO adsorption isotherms on 1 have a threshold pressure (P th) for abrupt accommodation of Me2CO molecules, which is regarded as the equilibrium pressure for the inclusion reaction of Me2CO

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Abstract  

The dynamics of redox related elements (Fe, Co, Zn, and Se) were studied using instrumental neutron activation analysis as a function of rat age in the range of 4 to 16 weeks. Activity levels of glutathione peroxidase (GSH-Px), thiobarbituric acid reactive substance (TBARS) were assayed, and hydrogen peroxide (H2O2) concentrations were measured for the same liver homogenates using an X-band ESR spectrometer. The oxidative stress, the aging effect, and the mineral valance are discussed.

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The postnatal development of the corticothalamic projection from the lateral suprasylvian cortex (LS) to the lateral medialis-suprageniculate nucleus (LM-Sg) of the cat thalamus was assessed by means of the anterograde tracer biocytin. In the adult, two types of corticothalamic fibers were found: type I established a network of fine fibers present throughout the LM-Sg, it was characterized by a linear sequence of small (less than 0.5 m in diameter), single terminal boutons making contact mainly with thin dendrites and/or dendritic spines. Type II, found less frequently, gave off short, side branches near axon terminals and formed clusters of 5-10 large terminal boutons (0.5-1.5 m in diameter), making contact predominately with medium-sized dendrites and/or vesicle-containing profiles, forming a synaptic glomerulus. At birth (P0), anterogradely-labeled fibers were found in the LM-Sg as in adults. In the early postnatal period (until P6) as well as around the time of eye-opening (P7-P10) to P21, neonatal fibers were largely unbranched many of them having axons tipped with growth cones. Axon terminals containing synaptic vesicles were rarely observed but when present these exhibited considerable variation in their morphological appearance of synapses. Thus, it was not possible to categorize them into the two types of axons which characterize the adult. After P25, terminal swellings bearing a close resemblance to those of type II fibers begin to appear. In this way, the main two corticothalamic fiber types could be identified. These findings demonstrate that significant postnatal changes occur in the synaptology of corticothalamic fibers in the LM-Sg, particularly with the maturation of type II fibers.

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Abstract  

Time series of the distribution of bio-trace elements in the upper abdomen of living rats were examined using the in vivo multitracer analysis technique. The in vivo dynamics of the elements were estimated by comparison with the distribution of 74As. Vanadium, Mn, Fe, Co, Zn, Se, and Rb were distributed in tissues of the upper abdomen, i.e., mainly in the liver. Be, Sr, and Y might be in the blood or bone at a low level and in the excretion stage already. Dynamics of bio-trace elements were noninvasively obtained in a living rat within one hour after administration.

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Abstract  

Affinity of several bio-trace elements to various reconstructed lipid membranes (liposomes) was assessed using multitracer analysis technique (MTAT). To estimate affinity of bio-trace elements to the sub-cellular components such as lipid membranes, MTAT was applied to the various reconstructed liposomes. Phosphatidylcholine and sphingomyelin liposomes showed a similar pattern of elemental affinity. Phosphatidylserine, phosphatidylglycerol, and phosphatidylinositol liposomes showed another similar pattern of elemental affinity, except that phosphatidylinositol liposome has no affinity to vanadium.

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Journal of Thermal Analysis and Calorimetry
Authors: K. Fujii, Y. Matsumoto, Y. Kaieda, D. Kobayashi, Y. Umebayashi, and S. Ishiguro

Abstract  

Cobalt(II) chloro complexation has been studied by titration calorimetry and spectrophotometry in solvent mixtures of N-methylformamide (NMF) and N,N-dimethylformamide (DMF). It revealed that a series of mononuclear CoClnn (2–n)+ (n=1–4) complexes are formed in the mixtures of NMF mole fraction x NMF=0.05 and 0.25, and the CoCl+, CoCl3 and CoCl4 2– complexes in the mixture of x NMF=0.5, and their formation constants, enthalpies and entropies were obtained. As compared with DMF, the complexation is markedly suppressed in the mixtures, as well as in NMF. The decreasing formation constant of CoCl+ with the NMF content is mainly ascribed to the decreasing formation entropy. DMF is aprotic and thus less-structured, whereas NMF is protic to form hydrogen- bonded clusters. In DMF-NMF mixtures, solvent clusters in neat NMF are ruptured to yield new clusters involving DMF, the structure of which depends on the solvent composition. The entropy of formation of CoCl+ will be discussed in relation to the liquid structure of DMF, NMF and their mixtures.

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