215 research outputs found
The Conductance of Copper (II) Sulfate in Water at Various Temperatures
The present investigation was undertaken to obtain the thermodynamic properties of ion association reactions. The electrolytic conductances of copper(II) sulfate in water at the temperatures ranging from 5° to 45° C were measured in order to study the effect of temperature on ion association constants. The data were analyzed using Shedlovsky's method based on the Onsager's limiting law and ion association constants KA, equivalent coductances at infinite dilution ⊿ , were obtained. From the plot of logKA vs. 1/T over the whole temperature range following values obtained; ⊿H = 1.89 kcal deg-1 mol-1, ⊿G = -3.22 kcal deg-1 mol-1, ⊿S = 17.1 cal mol-1 at 25°C.Article信州大学理学部紀要 1(1): 31-37(1967)departmental bulletin pape
Magnetic dichroism study on MnCoGa thin film using a combination of X-ray absorption and photoemission spectroscopy
Using circularly polarised radiation and a combination of bulk-sensitive hard
X-ray photoelectron spectroscopy and X-ray-absorption spectroscopy (XAS) we
studied the electronic and magnetic structure of epitaxial
MnCoGa thin films. Spin resolved Bloch spectral functions,
density of states as well as charge and magnetisation densities were
investigated by a first-principles analysis of full potential, fully
relativistic Korringa--Kohn--Rostoker calculations of the electronic structure.
The valence states were experimentally investigated by using linear dichroism
in the angular distribution and comparing the results to spin-resolved
densities of states. The linear dichroism in the valence band enabled a
symmetry analysis of the contributing states. The spectra were in good
agreement with the theoretical partial density of states. The element-specific,
spin-resolved, unoccupied densities of states for Co and Mn were analysed by
using XAS and X-ray magnetic circular dichroism (XMCD) at the edges.
The spectra were influenced by strong correlation effects. XMCD was used to
extract the site resolved magnetic moments. The experimental values of and agree very well with the
calculated magnetic moments. Magnetic circular dichroism in angle-resolved
photoelectron spectroscopy at the Mn and Co core level exhibited a
pronounced magnetic dichroism and confirmed the localised character of the Mn
valence states
Perpendicularly magnetized Mn-Co-Ga-based thin films with high coercive field
MnCoGa epitaxial thin films were grown on MgO substrates by
magnetron co-sputtering. Structures were tetragonal or cubic depending on Co
content. Composition dependence of saturation magnetization and uniaxial
magnetic anisotropy of the films were investigated. A high (1.2 MJ
m) was achieved for the MnCoGa film with the
magnetic moment 0.84. Valence band spectra were obtained by hard X-ray
photoelectron spectroscopy. Sharp peaks in the cubic case, which were absent in
the tetragonal case, prove that a van Hove singularity causes a band
Jahn-Teller effect with tetragonal distortion. Observations agree well with the
first-principles calculations
A bacterial enzyme degrading the model lignin compound β-etherase is a member of the glutathione-S-transferase superfamily
AbstractCleavage of β-aryl ether linkages is essential in lignin degradation. We identified another β-etherase gene (ligF), which contains an open reading frame of 771 bp and lies between genes coding Cα-dehydrogenase (ligD) and β-etherase (ligE). The β-etherase activity of LigF expressed in Escherichia coli was more than 80 times as high as that of LigE. ligF and ligE are homologous to glutathione-S-transferase, and upon addition of glutathione a remarkable acceleration of β-etherase activity was found in E. coli carrying ligF. It is concluded that LigF plays a central role in β-aryl ether cleavage and that glutathione is the hydrogen donor in this reaction
Role of adenosine in the renal responses to contrast medium
Role of adenosine in the renal responses to contrast medium. Despite the development of non-ionic radiographic contrast media (CM), CM-induced nephropathy is a clinically important problem in patients with pre-existing renal insufficiency. We examined the effects of non-ionic CM (iohexol) on renal function in conscious dogs with and without renal insufficiency, and evaluated the effects of a non-selective (theophylline), an A1 selective (KW-3902), and an A2 selective adenosine antagonist (KF17837) on the renal responses to CM. In sham-operated group, iohexol (2ml/kg/min for 3min) increased effective renal plasma flow (ERPF) and glomerular filtration rate (GFR), whereas in renal insufficiency group (with subtotal nephrectomy), following transient increases in ERPF and GFR, CM markedly decreased ERPF (-46.5 ± 6.7%) and GFR (-51.2 ± 7.1%). In sham-operated group, theophylline and KF17837 markedly attenuated CM-induced increases in ERPF and GFR, while KW-3902 had no effects on CM-induced increases in ERPF or GFR. In renal insufficiency group, initial increases in ERPF and GFR were blunted by theophylline and KF17837. In contrast, the subsequent decreases in ERPF and GFR were attenuated by theophylline (%ΔERPF, -12.2 ± 3.2% vs. -46.6 ± 6.7%, P < 0.01; %ΔGFR, 4.3 ± 2.5% vs. -51.0 ± 7.1%, P < 0.01), and were completely prevented by KW-3902 (%ΔERPF, 10.8 ± 2.9%; %ΔGFR, 23.8 ± 4.4%), whereas KF17837 aggravated ERPF (-73.3 ± 5.3%) and GFR (-78.4 ± 5.3%). These data indicate that in normal renal function, iohexol elicits renal vasodilation by activating mainly the adenosine A2 receptors. In contrast, in impaired renal function, CM induces both A2 and A1 activation; the former is associated with the initial renal vasodilation, while the latter is responsible for the sustained aggravation of renal hemodynamics
CCN3 (NOV) Drives Degradative Changes in Aging Articular Cartilage
Aging is a major risk factor of osteoarthritis, which is characterized by the degeneration of articular cartilage. CCN3, a member of the CCN family, is expressed in cartilage and has various physiological functions during chondrocyte development, differentiation, and regeneration. Here, we examine the role of CCN3 in cartilage maintenance. During aging, the expression of Ccn3 mRNA in mouse primary chondrocytes from knee cartilage increased and showed a positive correlation with p21 and p53 mRNA. Increased accumulation of CCN3 protein was confirmed. To analyze the effects of CCN3 in vitro, either primary cultured human articular chondrocytes or rat chondrosarcoma cell line (RCS) were used. Artificial senescence induced by H2O2 caused a dose-dependent increase in Ccn3 gene and CCN3 protein expression, along with enhanced expression of p21 and p53 mRNA and proteins, as well as SA-beta gal activity. Overexpression of CCN3 also enhanced p21 promoter activity via p53. Accordingly, the addition of recombinant CCN3 protein to the culture increased the expression of p21 and p53 mRNAs. We have produced cartilage-specific CCN3-overexpressing transgenic mice, and found degradative changes in knee joints within two months. Inflammatory gene expression was found even in the rib chondrocytes of three-month-old transgenic mice. Similar results were observed in human knee articular chondrocytes from patients at both mRNA and protein levels. These results indicate that CCN3 is a new senescence marker of chondrocytes, and the overexpression of CCN3 in cartilage may in part promote chondrocyte senescence, leading to the degeneration of articular cartilage through the induction of p53 and p21
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