115 research outputs found

    Development of a 4.2 V aqueous hybrid electrochemical capacitor based on MnO2 positive and protected Li negative electrodes

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    An aqueous hybrid electrochemical capacitor consisting of a capacitive manganese oxide (MnO2) positive electrode and a water-stable, protected Li negative electrode in near-neutral aqueous electrolyte (1.0 M Li2SO4, pH = 5.5) is demonstrated. Galvanostatic charge/discharge cycling tests were conducted with pouched cells, offering a cell voltage of 4.2 V with maximum specific energy of 753 W h kg(-1) based on the positive electrode. The combination of a pseudocapacitive MnO2 positive and a Li negative electrode offers high specific charge and cell voltage, resulting in an aqueous hybrid electrochemical capacitor having exceptionally high specific energy.ArticleJOURNAL OF POWER SOURCES. 241:572-577 (2013)journal articl

    Towards Implantable Bio-Supercapacitors: Pseudocapacitance of Ruthenium Oxide Nanoparticles and Nanosheets in Acids, Buffered Solutions, and Bioelectrolytes

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    Metal oxides, in particular ruthenium-based oxides, are promising electrode materials for aqueous pseudocapacitors. Strong acids or bases are favored over neutral electrolytes owing to the higher capacitance. Here we explore the pseudocapacitive behavior of ruthenium oxide nanoparticles and nanosheets in near neutral pH as an environmentally benign electrolyte. The pseudocapacitive charge storage in poorly-crystalline hydrous RuO2 nanoparticles, and highly-crystalline RuO2 nanosheets were investigated in acetic acid-lithium acetate (AcOH-AcOLi) buffered solutions. It is shown that capacitance values as high as 1,038 F g(-1) can be achieved in AcOH-AcOLi buffered solutions with RuO2 nanosheets, which is 44% higher than the benchmark RuO2 nH(2)O in H2SO4 electrolyte (720 F g(-1)). Furthermore, comparable performance was obtained in phosphate buffered saline and fetal bovine serum. The mechanism of the pseudocapacitive properties is discussed based on the difference in the surface redox behavior of different RuO2 nanomaterials in acid, neutral, buffered solutions, and in weak acid. (C) The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved.ArticleJOURNAL OF THE ELECTROCHEMICAL SOCIETY. 162(5):A5001-A5006 (2015)journal articl

    4 V class aqueous hybrid electrochemical capacitor with battery-like capacity

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    A new aqueous hybrid electrochemical capacitor consisting of a porous positive capacitive electrode and a water-stable multilayered Li negative electrode is demonstrated. The new cell design affords cell voltages close to 4 V in a mild aqueous electrolyte. Application of a pseudocapacitive positive electrode with high specific charge results in specific energy comparable to present rechargeable batteries.ArticleRSC ADVANCES. 2(32):12144-12147 (2012)journal articl

    Application of an Improved Micro-amount of Virion Enrichment Technique (MiVET) for the Detection of Avian Influenza A Virus in Spiked Chicken Meat Samples

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    Highly sensitive detection of pathogens is effective for screening meat during quarantine inspection and export. The “micro-amount of virion enrichment technique” (MiVET) was recently developed, which is a new method combining virus concentration with immunomagnetic beads and simple RNA extraction with sodium dodecyl benzenesulfonate (SDBS) for the specific and sensitive detection of avian influenza viruses (AIVs). AIV subtypes H3N2 and H4N2 were used to spike the surface of chicken breast meat samples. The modified MiVET protocol was tested by comparing it against three different homogenate preparation conditions, as well as in samples with added α-amylase and collagenase to digest inhibitors. The performance of the modified MiVET was evaluated by real-time RT-PCR assay targeting the matrix gene. Compared with conventional RNA extraction, the modified MiVET reproducibly concentrated AIVs in chicken meat samples with 100–1000-fold improvement by 60 s-hand homogenization. The 30 s- and 60 s-stomacher homogenizations resulted 100-fold and 10–100-fold improvement, respectively. The modified MiVET required < 60 min from homogenate preparation to final RNA elution. Further, use of the modified MiVET also decreased the rate of false-negative results. The modified MiVET is effective for the rapid and highly sensitive detection of AIVs in chicken meat samples, and can be applied to quarantine and export inspection at airports and seaports

    Cryptic diversity of Japanese Diaphanosoma (Crustacea: Cladocera) revealed by morphological and molecular assessments

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    We found 5 distinct species of Diaphanosoma from a variety of lakes in Japan according to morphological examination and genetic analyses with the DNA sequences of mitochondrial 16S ribosomal RNA and cytochrome c oxidase subunit I genes (mtCOI). Previously, D. brachyurum was thought to occur at temperate regions including Japan; however, we did not find D. brachyurum in Japan. Instead, we found D. cf. amurensis, which inhabited mainly natural habitats of high altitude and latitude, and D. cf. dubium, D. cf. orientalis, and D. cf. macrophthalma, which occurred in a variety of habitats from large natural lakes to small artificial ponds at low altitude. We also found another species from only one pond that possessed mtCOI sequences that matched almost completely with those from North American specimens and thus was probably nonindigenous Diaphanosoma. Concordance between the results of morphological identifications and genetic analyses showed that the DNA barcodes established in this study are useful to identify Diaphanosoma species in Japan and adjacent areas

    Synthesis of ordered mesoporous ruthenium by lyotropic liquid crystals and its electrochemical conversion to mesoporous ruthenium oxide with high surface area

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    In ordered to prepare high capacitance pseudo-capacitive oxides, it is important to design nanostructures with appreciable mesopores. Supramolecular templating has become a popular method to synthesize ordered mesoporous metals; however, the application of the same technique to synthesis of high surface area oxides is more demanding. We present here, the synthesis of ordered mesoporous ruthenium metal by lyotropic liquid crystal templating and its electrochemical conversion to ordered mesoporous ruthenium oxide by a simple, room temperature procedure. The bulk, unsupported metallic ordered mesoporous ruthenium exhibits high surface area of 110 m(2) g(-1), which is comparable to typical supported Ru nanoparticles. The oxide analogue gives a high specific capacitance of 376 Fg(-1), owing to the porous structure. These results demonstrate a possible facile and generic process to synthesize oxides with ordered nanostructures by utilization of the various phases that can be obtained with lyotropic liquid crystalline templates such as cubic, hexagonal, lamellar, etc.ArticleJOURNAL OF POWER SOURCES. 204:244-248 (2012)journal articl

    Inhibition of Uterine Sarcoma Cell Growth through Suppression of Endogenous Tyrosine Kinase B Signaling

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    Uterine leiomyosarcoma is an aggressive tumor typically found at advanced stages due to difficulties with early diagnosis. Because uterine leiomyosarcoma is resistant to conventional radiation and chemotherapy, the development of more potent medical therapeutics is anticipated. Using quantitative real-time RT-PCR and immunostaining, we found the expression of brain-derived neurotrophic factor (BDNF) and neurotropin-4/5, together with their receptor, tyrosine kinase B (TrkB), in different uterine sarcoma cell lines and primary tumor samples from uterine leiomyosarcoma patients. We noted that levels of BDNF were more abundant than those of neurotropin-4/5. Moreover, the expression of TrkB and its ligands was elevated in a multidrug-resistant cell line and samples obtained from patients with leiomyosarcoma. In cultured uterine sarcoma cells, inhibition of endogenous TrkB signaling by treatment with either the soluble TrkB ectodomain or the Trk receptor inhibitor, K252a, suppressed cell proliferation and increased apoptosis based on cell viability and proliferation, in situ terminal deoxynucleotidyl transferase-mediated 2\u27-deoxyuridine 5\u27-triphosphate nick end-labeling and caspase-3/7 assays, whereas an inactive plasma membrane nonpermeable K252b was ineffective. Correspondingly, treatment with exogenous BDNF increased cell proliferation. In in vivo studies in athymic nude mice bearing multidrug-resistant uterine sarcoma cell tumors, we demonstrate suppression of tumor growth by treatment with K252a, but not K252b, as reflected by decreased cell proliferation and increased levels of apoptosis and caspase-3/7 activities without obvious side effects. Our findings indicated that endogenous signaling of the TrkB pathway contributed to uterine sarcoma cell growth, and inhibition of TrkB signaling in these tumors could provide a novel medical therapy for patients with uterine sarcomas

    A at Single Nucleotide Polymorphism-358 Is Required for G at -420 to Confer the Highest Plasma Resistin in the General Japanese Population

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    Insulin resistance is a feature of type 2 diabetes. Resistin, secreted from adipocytes, causes insulin resistance in mice. We previously reported that the G/G genotype of single nucleotide polymorphism (SNP) at −420 (rs1862513) in the human resistin gene (RETN) increased susceptibility to type 2 diabetes by enhancing its promoter activity. Plasma resistin was highest in Japanese subjects with G/G genotype, followed by C/G, and C/C. In this study, we cross-sectionally analyzed plasma resistin and SNPs in the RETN region in 2,019 community-dwelling Japanese subjects. Plasma resistin was associated with SNP-638 (rs34861192), SNP-537 (rs34124816), SNP-420, SNP-358 (rs3219175), SNP+299 (rs3745367), and SNP+1263 (rs3745369) (P<10−13 in all cases). SNP-638, SNP -420, SNP-358, and SNP+157 were in the same linkage disequilibrium (LD) block. SNP-358 and SNP-638 were nearly in complete LD (r2 = 0.98), and were tightly correlated with SNP-420 (r2 = 0.50, and 0.51, respectively). The correlation between either SNP-358 (or SNP-638) or SNP-420 and plasma resistin appeared to be strong (risk alleles for high plasma resistin; A at SNP-358, r2 = 0.5224, P = 4.94×10−324; G at SNP-420, r2 = 0.2616, P = 1.71×10−133). In haplotypes determined by SNP-420 and SNP-358, the estimated frequencies for C-G, G-A, and G-G were 0.6700, 0.2005, and 0.1284, respectively, and C-A was rare (0.0011), suggesting that subjects with A at −358, generally had G at −420. This G-A haplotype conferred the highest plasma resistin (8.24 ng/ml difference/allele compared to C-G, P<0.0001). In THP-1 cells, the RETN promoter with the G-A haplotype showed the highest activity. Nuclear proteins specifically recognized one base difference at SNP-358, but not at SNP-638. Therefore, A at -358 is required for G at −420 to confer the highest plasma resistin in the general Japanese population. In Caucasians, the association between SNP-420 and plasma resistin is not strong, and A at −358 may not exist, suggesting that SNP-358 could explain this ethnic difference
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