Neutral metal−benzene complexes, M
n
(benzene)
m
(M = Sc to Cu), are produced for all of
the 3d transition metals in the gas phase by using the laser vaporization method. These
species are characterized by mass spectrometry, photoionization spectroscopy, and chemical
probe experiments. Depending on the metal, there are two types of structures for
M
n
(benzene)
m
: multiple-decker sandwich structures and metal clusters fully covered with
benzene molecules (rice-ball structures). The former sandwich structure is characteristic of
the complexes for early transition metals (Sc−V), whereas the latter is formed for late
transition metals (Fe−Ni). Electronic structures of M1(benzene)
x
(x = 1, 2) complexes are
investigated through systematic measurements of ionization energies (E
i's).
Polarization of sintered hydroxyapatite (HAp) ceramics by application of an external dc field at higher temperature was analyzed by thermally stimulated depolarization current (TSDC) measurements. The mechanisms for the polarization and depolarization of HAp were discussed in relation to the instability of the protons in the hydroxide groups. The TSDC spectra consisted of broad peaks, while the ferroelectric substances such as the BaTiO3 ceramics exhibited a sharp peak. Although the maximum current density of 7.87 nA cm−2 for the HAp polarized at 400 °C under 1.0 kV cm−1 was approximately 1/12 lower than that of BaTiO3, the polarization charge of 14.9 μC cm−2 was almost twice as large as that of BaTiO3. Considering the activation energy of 0.72–0.89 eV for the depolarization, it was revealed that the polarization of HAp was ascribed to the migration of protons in the columnar OH− channels with a micrometer-order distance. It was also found that the polarization charge was large and long enough to enhance the biological reactivity of HAp ceramics for biomedical implants.
Purpose: Colorectal carcinogenesis is thought to be related to abdominal obesity and insulin resistance. To investigate whether visceral fat accumulation contributes to colorectal carcinogenesis, we examined its accumulation and the levels of the adipose tissue^derived hormone adiponectin in Japanese patients with colorectal adenoma. Experimental Design: Fifty-one consecutive Japanese patients ages z40 years and with colorectal adenoma were subjected to measurement of visceral fat area by computed tomography scanning and plasma adiponectin concentration. The patients also underwent the 75-g oral glucose tolerance test. Insulin resistance was calculated by the homeostasis metabolic assessment (HOMA-IR) method. The controls were 52 Japanese subjects ages z40 years and without colorectal polyp. Cigarette smokers and subjects who consumed alcohol (z30 g ethanol/d) were excluded. Results: The patients with colorectal adenoma showed significantly more visceral fat area and significantly less plasma adiponectin concentration in comparison with the controls [odds ratio (OR), 2.19; 95% confidence interval (95% CI), 1.47-3.28; P < 0.001 and OR, 0.24; 95% CI, 0.14-0.41; P < 0.001, respectively] by logistic regression analysis. HOMA-IR index was also associated with colorectal adenoma (OR 2.60; 95% CI, 1.20-5.64; P = 0.040). Visceral fat area and adiponectin were associated with adenoma number (1, 2, z 3), the size of the largest adenoma (<10 and z10 mm), and adenoma histology (tubular and tubulovillous/villous). Conclusions: These results suggest an association of visceral fat accumulation and decreased plasma adiponectin concentration with colorectal adenoma in Japanese patients. This study may offer a new insight to understanding the relationship of colorectal carcinogenesis with abdominal obesity and insulin resistance.
Results showed the up-regulation of these three histone-modifying molecules in this series of colorectal cancers and suggested that monitoring of CBP and p300 may assist prediction of the prognosis in patients with colorectal adenocarcinoma.
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