Preparation of superparamagnetic magnetite nanoparticles by reverse precipitation method: Contribution of sonochemically generated oxidants.

Magnetic iron oxide nanoparticles were successfully prepared by a novel reverse precipitation method with the irradiation of ultrasound. TEM, XRD and SQUID analyses showed that the formed particles were magnetite (Fe(3)O(4)) with about 10nm in their diameter. The magnetite nanoparticles exhibited superparamagnetism above 200K, and the saturation magnetization was 32.8emu/g at 300K. The sizes and size distributions could be controlled by the feeding conditions of FeSO(4).7H(2)O aqueous solution, and slower feeding rate and lower concentration lead to smaller and more uniform magnetite nanoparticles. The mechanisms of sonochemical oxidation were also discussed. The analyses of sonochemically produced oxidants in the presence of various gases suggested that besides sonochemically formed hydrogen peroxide, nitrite and nitrate ions contributed to Fe(II) ion oxidation

Mild Electrical Stimulation with Heat Shock Ameliorates Insulin Resistance via Enhanced Insulin Signaling

Low-intensity electrical current (or mild electrical stimulation; MES) influences signal transduction and activates phosphatidylinositol-3 kinase (PI3K)/Akt pathway. Because insulin resistance is characterized by a marked reduction in insulin-stimulated PI3K-mediated activation of Akt, we asked whether MES could increase Akt phosphorylation and ameliorate insulin resistance. In addition, it was also previously reported that heat shock protein 72 (Hsp72) alleviates hyperglycemia. Thus, we applied MES in combination with heat shock (HS) to in vitro and in vivo models of insulin resistance. Here we show that 10-min treatment with MES at 5 V (0.1 ms pulse duration) together with HS at 42°C increased the phosphorylation of insulin signaling molecules such as insulin receptor substrate (IRS) and Akt in HepG2 cells maintained in high-glucose medium. MES (12 V)+mild HS treatment of high fat-fed mice also increased the phosphorylation of insulin receptor β subunit (IRβ) and Akt in mice liver. In high fat-fed mice and db/db mice, MES+HS treatment for 10 min applied twice a week for 12–15 weeks significantly decreased fasting blood glucose and insulin levels and improved insulin sensitivity. The treated mice showed significantly lower weight of visceral and subcutaneous fat, a markedly improved fatty liver and decreased size of adipocytes. Our findings indicated that the combination of MES and HS alleviated insulin resistance and improved fat metabolism in diabetes mouse models, in part, by enhancing the insulin signaling pathway

Sonochemical preparation of magnetite nanoparticles by reverse precipitation method

Magnetic iron oxide nanoparticles were successfully prepared by reverse precipitation method with the assistance of ultrasound. Obtained nanoparticles were identified as magnetite (Fe_3O_4) by XRD measurement. It was found that obtained magnetite nanoparticles have small sizes (about 10.7 ±2.9 nm in diameter) and spherical shape by TEM observations. In reverse precipitation method, the dropping conditions of aqueous FeSO_4 solution affect on the sizes and uniformity of the products.Nagasaki Symposium on Nano-Dynamics 2008 (NSND2008) 平成20年1月29日(火)於長崎大学 Poster Presentatio

Preparation of superparamagnetic magnetite nanoparticles by reverse precipitation method: Contribution of sonochemically generated oxidants.

Magnetic iron oxide nanoparticles were successfully prepared by a novel reverse precipitation method with the irradiation of ultrasound. TEM, XRD and SQUID analyses showed that the formed particles were magnetite (Fe(3)O(4)) with about 10nm in their diameter. The magnetite nanoparticles exhibited superparamagnetism above 200K, and the saturation magnetization was 32.8emu/g at 300K. The sizes and size distributions could be controlled by the feeding conditions of FeSO(4).7H(2)O aqueous solution, and slower feeding rate and lower concentration lead to smaller and more uniform magnetite nanoparticles. The mechanisms of sonochemical oxidation were also discussed. The analyses of sonochemically produced oxidants in the presence of various gases suggested that besides sonochemically formed hydrogen peroxide, nitrite and nitrate ions contributed to Fe(II) ion oxidation

π‑Extended Planarized Triphenylboranes with Thiophene Spacers

Planarized triphenylboranes extended with thiophene or bithiophene spacers were synthesized, which showed intense fluorescences in solution and reversible redox waves for reduction in cyclic voltammetry. Organic light-emitting diodes (OLEDs) using these compounds as an electron-transporting material were fabricated

Mild electrical stimulation increases stress resistance and suppresses fat accumulation via activation of LKB1-AMPK signaling pathway in C. elegans.

Electrical current at physiological strength has been applied as a therapeutic approach for various diseases. Several of our works showed that mild electrical stimulation (MES) at 0.1-ms pulse width has positive impact on organisms. But despite the growing evidence of the beneficial effects of MES, its effects on individual animals and the molecular underpinnings are poorly understood and rarely studied. Here, we examined the effects of MES on individual animal and its mechanisms by mainly using Caenorhabditis elegans, a powerful genetic model organism. Interestingly, MES increased stress resistance and suppressed excess fat accumulation in wild-type N2 worms but not in AMPK/AAK-2 and LKB1/PAR-4 mutant worms. MES promoted the nuclear localization of transcription factors DAF-16 and SKN-1 and consequently increased the expression of anti-stress genes, whereas MES inhibited the nuclear localization of SBP-1 and suppressed the expression of lipogenic genes. Moreover, we found that MES induced the activation of LKB1/PAR4-AMPK/AAK2 pathway in C. elegans and in several mammalian cell lines. The mitochondrial membrane potential and cellular ATP level were slightly and transiently decreased by MES leading to the activation of LKB1-AMPK signaling pathway. Together, we firstly and genetically demonstrated that MES exerts beneficial effects such as stress resistance and suppression of excess fat accumulation, via activation of LKB1-AMPK signaling pathway

Establishment of a Screening Method for Epstein-Barr Virus-Associated Gastric Carcinoma by Droplet Digital PCR

Background: Epstein-Barr virus-associated gastric carcinoma (EBVaGC) is classified as one of the molecular subtypes of gastric cancer. We used droplet digital polymerase chain reaction (ddPCR) to enable highly sensitive and quantitative detection of EBV. Methods: EBV-DNA load was calculated based on the copy number of the BamH1-W fragment of EBV by ddPCR, and the cut-off value of EBV-DNA load was set. We conducted both ddPCR and EBER1 ISH to examine whether their results coincided in 158 gastric cancer specimens of unknown EBV status. We prepared 26 biopsy specimens and 49 serum samples including EBVaGC and assayed them by ddPCR. Results: The median values of EBV-DNA load for EBVaGC and EBV-negative control were 17.0 and 0.00308, respectively. A cut-off value of 0.032 was determined for which the sensitivity was 1. Among the 158 gastric cancer specimens, 14 lesions were judged as EBV-positive by the 0.032 cut-off value determined by ddPCR. The results of ddPCR and EBER1 ISH were in complete agreement. Even when using a biopsy specimen as a sample for ddPCR, the EBV-DNA load of all EBVaGCs was larger than the cut-off value. Conclusions: We established a new method of diagnosing EBVaGC from tissue samples by ddPCR