Search

have investigated the electronic and optical properties of inorganic halide perovskites Cs2TiX6 (X = Br, I) using first-principles calculations based on the density functional theory, comparing them with those of CH3NH3PbX3 (X = Br, I). In particular, the absorption coefficients are calculated using the four-component spinors obtained as the solutions of the Dirac–Kohn–Sham equations. Our results show that Cs2TiX6 possess larger absorption coefficients than CH3NH3PbX3 in the main part of the solar spectrum. Furthermore, we calculate the nuclear quadrupole coupling constant CQ of 79Br and 127I for Cs2TiX6 prior to experiments and evaluate the reliability of our calculated CQ carefully. The reliability of the calculations is confirmed by comparing the calculated and experimental CQ for the isostructural material K2PtBr6 as well as by examining those for MAPbX3 and CsSnI3. [ABSTRACT FROM AUTHOR]

We study double perovskite Sr2FeXO6 (X = Mo, Re) ultrathin films (UTFs) and their heterostructures with a SrTiO3 substrate by first-principles calculations based on density functional theory. It is found that the UTFs and their heterostructures are all half-metallic despite being extremely thin. [ABSTRACT FROM AUTHOR]

AT motif binding factor 1 (ATBF1) is a transcriptional regulator that functions as a tumour suppressor to negatively affect cancer cell growth. In the present study four specific polyclonal antibodies against ATBF1 were generated, and the expression and intracellular localization of ATBF1 in colonic mucosae, polyps, adenoma and adenocarcinoma tissue samples were investigated. The four polyclonal antibodies produced were as follows: MB34 and MB49, which recognize the N‑ and C‑terminal fragments of ATBF1, respectively; and D1‑120 and MB44, which recognize the middle fragments of ATBF1 that contain three nuclear localization signals (NLS). In total, 191 colon samples were examined by immunohistochemical analysis. In addition, colon cancer cells were transfected with four ATBF1 expression vectors, and the subcellular localization of each fragment was examined. Normal colon mucosal cells were not observed to express ATBF1. However, a small number of hyperplastic polyps, serrated adenomas and tubular adenomas expressed ATBF1. Colon cancer cells were observed to express D1‑120‑ and MB44‑reactive middle fragments of ATBF1 in their cell nuclei. However, the N‑ and C‑terminal fragments of ATBF1 did not translocate to the nucleus. Transfection of ATBF1 fragments revealed cleavage of the ATBF1 protein and nuclear translocation of the cleaved middle portion containing the NLS. A positive correlation between the cytoplasmic localization of the N‑ and C‑termini of ATBF1, nuclear localization of the middle portion of ATBF1 and malignant cancer cell invasion was observed. In conclusion, the results of the present study suggest that alterations in the expression and subcellular localization of ATBF1, as a result of post‑transcriptional modifications, are associated with malignant features of colon tumours [ABSTRACT FROM AUTHOR]

Pioglitazone (PGZ), a peroxisome proliferator-activated receptor agonist, which is known as a type 2 diabetes drug, inhibits cell proliferation in various cancer cell lines, including prostate carcinomas. This study focused on the effect of PGZ on prostate carcinogenesis using a transgenic rat for an adenocarcinoma of prostate (TRAP) model. Adenocarcinoma lesions as a percentage of overall lesions in the ventral prostate were significantly reduced by PGZ treatment in a dose-dependent manner. The number of adenocarcinomas per given area in the ventral prostate was also significantly reduced by PGZ treatment. The Ki67 labeling index in the ventral prostate was also significantly reduced by PGZ. Decreased cyclin D1 expression in addition to the inactivation of both p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)κB were detected in PGZ-treated TRAP rat groups. In LNCaP, a human androgen-dependent prostate cancer cell line, PGZ also inhibited cyclin D1 expression and the activation of both p38MAPK and NFκB. The suppression of cultured cell growth was mainly regulated by the NFκB pathway as detected using specific inhibitors in both LNCaP and PC3, a human androgen-independent prostate cancer cell line. These data suggest that PGZ possesses a chemopreventive potential for prostate cancer. [ABSTRACT FROM AUTHOR]

Fermented brown rice and rice bran with Aspergillus oryzae (FBRA) is considered to have the potential to prevent chemically-induced carcinogenesis in multiple organs of rodents. In the present study, we evaluated the possible chemopreventive effects of FBRA against prostate tumorigenesis. Six-week-old male rats of the transgenic rat for adenocarcinoma of prostate (TRAP) strain were fed diets containing 5% or 10% FBRA for 15 weeks. Animals were sacrificed at 21 weeks of age, and the ventral and lateral prostate were removed for histopathological evaluation and immunoblot analyses. FBRA decreased the incidence of adenocarcinoma in the lateral prostate and suppressed the progression of prostate carcinogenesis. Treatment with FBRA induced apoptosis and inhibited cell proliferation in histologically high-grade prostatic intraepithelial neoplasias. Phospho-AMP-activated kinase α (Thr172) was up-regulated in the prostate of rats fed the diet supplemented with FBRA. These results indicate that FBRA controls tumor growth by activating pathways responsive to energy deprivation and suggest that FBRA has translational potential for the prevention of human prostate cancer. [ABSTRACT FROM AUTHOR]

Non-alcoholic steatohepatitis (NASH) has the potential to lead to the development of cirrhosis and hepatocellular carcinoma (HCC). Connexin (Cx) 32, a hepatocyte gap-junction protein, plays a preventive role in hepatocarcinogenesis. However, the precise contribution of Cx32 in the development of NASH has not been established. In this study, we aimed to clarify the role of Cx32 and the chemopreventive effect of luteolin, an antioxidant flavonoid, on the progression of NASH and NASH-related hepatocarcinogenesis. Cx32 dominant negative transgenic (Cx32ΔTg) and wild-type (Wt) rats at 10 weeks of age were given diethylnitrosamine and fed methionine–choline-deficient diet (MCDD) or MCDD with luteolin for 12 weeks. MCDD induced steatohepatitis and fibrosis along with increased inflammatory cytokine expression and reactive oxygen species in the liver. These effects were more severe in Cx32ΔTg rats as compared with Wt rats, and significantly suppressed by luteolin in both genotypes. Concerning NASH-related hepatocarcinogenesis, the number of glutathione S-transferase placental form (GST-P)-positive foci was greater in Cx32ΔTg versus Wt rats, and significantly reduced by luteolin in Cx32ΔTg rats. Microarray analysis identified brain expressed, X-linked 1 (Bex1) as an upregulated gene in Cx32ΔTg rat liver. Quantitative RT-PCR and in situ hybridization revealed that increased Bex1 mRNA was localized in GST-P-positive foci in Cx32ΔTg rats, and the expression level was significantly decreased by luteolin. Moreover, Bex1 knockdown resulted in significant growth inhibition of the rat HCC cell lines. These results show that Cx32 and luteolin have suppressive roles in inflammation, fibrosis and hepatocarcinogenesis during NASH progression, suggesting a potential therapeutic application for NASH. [ABSTRACT FROM AUTHOR]

We study the electric field (EF) effects on the magnetic anisotropy in the MgO/TM/Au (TM = Fe, Co) systems with (001) and (111) orientations using relativistic first-principles calculations based on the density functional theory. We find that the perpendicular magnetic anisotropy of the MgO/TM/Au(001) system is enhanced by the EF that decreases the number of electrons in the system. The magnetic anisotropy energy (MAE) and its EF dependence of the MgO/Fe/Au(001) system is found to be in a semi-quantitative agreement with the experimental results with successful reproduction of the sign of the measured EF dependence. Furthermore, the EF dependence of the MAE of the MgO/Co/Au(001) system is found to be very large due to the structural relaxation of the Co-O interatomic distance and the decrease in the number of electrons in the Co atom caused by the EF. This result is attributed to the general trend that the perpendicular magnetic anisotropy of the Co layer is affected significantly when in contact with an inert layer at an interlayer distance of about 2 Å. On the contrary, we find that the MgO/TM/Au(111) system shows almost no EF dependence of the MAE. This result is attributed to the existence of a strong TM-O covalent bond associated with the oxidation of the TM atom by the O atom [ABSTRACT FROM AUTHOR]

Glutathione S-transferase placental form (GST-P), one of the glutathione S-transferases family of detoxification enzymes, is a very useful marker of rat liver pre-neoplastic lesions. We here investigated the gene expression profile in GST-P positive foci as compared with surrounding GST-P negative areas in the same liver of rats treated with diethylnitrosamine and then 2-acetylaminofluorene combined with partical hepatectomy. GST-P positive foci were harvested by laser microdissection and total RNAs were extracted to allow gene expression profiles to be assessed by cDNA microarray assays. Transaldolase, rat aflatoxin B1 aldehyde reductase and gamma-glutamylcysteine synthetase were found as up-regulated genes and regucalcin as a down-regulated gene, in line with findings for hepatocellular carcinomas. The results indicate that the approach adopted is useful for understanding mechanisms of hepatocarcinogenesis and identification of new markers for rat liver pre-neoplastic foci. [ABSTRACT FROM AUTHOR]

We have studied the optical absorption of lead-free double perovskites Cs2AgBiBr6 and Cs2InBiBr6 using the solutions of the Dirac–Kohn–Sham equations. It is found that the absorption coefficient of Cs2AgBiBr6 in the high-energy part of the solar spectrum is considerably large and that the absorption spectrum of Cs2InBiBr6 shows strong similarity to that of CH3NH3PbI3 in the main part of the solar spectrum. [ABSTRACT FROM AUTHOR]

We study the structural, electronic, and optical properties of MBiS2 (M = Ag, Na) using the relativistic all-electron calculations. We find that for both M = Ag and Na, the and superstructures are the lowest-energy superstructures. and MBiS2 are indirect band-gap semiconductors with the differences between the indirect and direct band gaps, Δ, of about 0.5 and 0.1 eV for M = Ag and Na, respectively. and MBiS2 exhibit high absorption coefficients of the order of 105 cm−1. Employing the spectroscopically limited maximum efficiency as a metric for quantifying the photovoltaic performance, it is found that the power conversion efficiency in the thick-film limit for M = Na is 32% because of its small Δ while that for M = Ag is 15% because of its large Δ. [ABSTRACT FROM AUTHOR]

We study the electronic and optical properties of the mixed valence perovskite Cs2Au2X6 (X = Cl, Br, I) using the fully relativistic all-electron calculations. We find that Cs2Au2X6 exhibits indirect fundamental band gaps although the differences between the indirect and direct band gaps are small. For the electric field of light perpendicular to the tetragonal c axis, Cs2Au2Br6 and Cs2Au2I6 exhibit the maximum absorption coefficient of about 20 × 104 cm−1 around the photon energy of 2 eV, which is considerably larger than that of CH3NH3PbI3. For the electric field of light parallel to the tetragonal c axis, the absorption coefficient of Cs2Au2I6 is comparable to that of CH3NH3PbI3 in the main part of the solar spectrum. Furthermore, we estimate the photovoltaic performance of Cs2Au2X6 employing the spectroscopically limited maximum efficiency as a metric and discuss its dependence on the film thicknes in detail. [ABSTRACT FROM AUTHOR]

Inorganic arsenic (arsenate and arsenite) is a known human carcinogen, inducing tumors of the skin, urinary bladder, and lung. Understanding the mechanism of inorganic arsenic carcinogenesis has been hampered by a lack of animal models. To define the urothelial effects of inorganic arsenic, we administered arsenate and arsenite in the diet or drinking water to rats and mice in several short-term experiments (2–10 weeks). Treatment with arsenate or arsenite in the drinking water or diet induced cytotoxicity and necrosis of the urothelial superficial layer and hyperplasia in rats and mice. Arsenate-induced changes occurred later in mice compared with arsenite-induced changes, but not in the rat. Hyperplasia in rats was evident by light microscopy at an earlier time point (2 weeks) than previously observed after treatment with dimethylarsinic acid (DMAV). The bromodeoxyuridine labeling index was increased in treated rats. We were unable to determine the bromodeoxyuridine labeling index in mice. The effects of inorganic arsenicals on the bladder were greater when administered in the drinking water than in the diet in rats and mice, but so was the overall toxicity to the animal. The female rat appeared more sensitive to the effects of inorganic arsenic than the male rat, but effects were similar in female and male mice. The mode of action of inorganic arsenic in rats and mice appears to involve urothelial cytotoxicity, increased cell proliferation and ultimately tumors. Cytotoxicity is likely due to the generation of reactive trivalent arsenicals excreted in the urine. [ABSTRACT FROM AUTHOR]