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Here, we propose a two-step pervaporation system with a high-silica CHA (chabazite) membrane, which has sufficient resistance to water and acid, to demonstrate the extraction and condensation of the formic acid formed by electroreduction of CO2. The kinetic diameters of water and formic acid are similar and smaller than the pore size of CHA, while the hydrated electrolyte ions (e.g., K+ and Cl−) are larger than the pore size of CHA. Consequently, the electrolyte ions are separated from the mixture of water and formic acid in the first desalination process, and then water molecules are easily removed from the mixture in the second dehydration process. From 300 ml of an approximately 3 wt% formic acid aqueous solution containing 0.5 M KCl, 10 ml of 18.2 wt% formic acid was obtained.

Abstract Porphyrin derivatives accumulate selectively in cancer cells and are can be used as carriers of drugs. Until now, the substituents that bind to porphyrins (mainly at the meso-position) have been actively investigated, but the effect of the functional porphyrin positions (β-, meso-position) on tumor accumulation has not been investigated. Therefore, we investigated the correlation between the functional position of substituents and the accumulation of porphyrins in cancer cells using cancer cells. We found that the meso-derivative showed higher accumulation in cancer cells than the β-derivative, and porphyrins with less bulky substituent actively accumulate in cancer cells. When evaluating the intracellular distribution of porphyrin, we found that porphyrin was internalized by endocytosis and direct membrane permeation. As factors involved in these two permeation mechanisms, we evaluated the affinity between porphyrin-protein (endocytosis) and the permeability to the phospholipid bilayer membrane (direct membrane permeation). We found that the binding position of porphyrin affects the factors involved in the transmembrane permeation mechanisms and impacts the accumulation in cancer cells.

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Abstract Platinum nanoparticle-embedded porous diamond spherical particles (PtNP@PDSPs), as an active and stable catalyst, were fabricated by spray-drying of an aqueous slurry containing nanodiamond (ND) particles, platinum nanoparticles (PtNP), and polyethylene glycol (PEG) to form ND/PtNP/PEG composite spherical particles, followed by removal of PEG and a short-time diamond growth on the surface. The average diameter of the PtNP@PDSPs can be controlled in the range of 1–5 μm according to the spray-drying conditions. The Brunauer-Emmett-Teller (BET) surface area and average pore diameter of the PtNP@PDSPs were estimated to be ca. 170–300 m2 g−1 and ca. 4–13 nm, respectively. When ND with the size of 20–30 nm was used, the size of PtNP in the PtNP@PDSP was almost unchanged at 5–6 nm even after high temperature processes and reuse test for catalytic reaction, showing stable supporting. The catalytic activity of the PtNP@PDSPs for the dehydrogenation of cyclohexane was higher than that for a Pt/C catalyst, which is attributed to the stable PtNP support by the three-dimensional packing of ND and efficient mass transfer via the interconnected through-hole pores in the PDSPs.

Background The growth and development of plants is deleteriously affected by various biotic and abiotic stress factors. Wounding in plants is caused by exposure to environmental stress, mechanical stress, and via herbivory. Typically, oxidative burst in response to wounding is associated with the formation of reactive oxygen species, such as the superoxide anion radical (O2•−), hydrogen peroxide (H2O2) and singlet oxygen; however, few experimental studies have provided direct evidence of their detection in plants. Detection of O2•− formation in plant tissues have been performed using various techniques including electron paramagnetic resonance spin-trap spectroscopy, epinephrine-adrenochrome acceptor methods, staining with dyes such as tetrazolium dye and nitro blue tetrazolium (NBT); however, kinetic measurements have not been performed. In the current study, we provide evidence of O2•− generation and its kinetics in the leaves of spinach (Spinacia oleracea) subjected to wounding. Methods Real-time monitoring of O2•− generation was performed using catalytic amperometry. Changes in oxidation current for O2•− was monitored using polymeric iron-porphyrin-based modified carbon electrodes (φ = 1 mm) as working electrode with Ag/AgCl as the reference electrode. Result The results obtained show continuous generation of O2•− for minutes after wounding, followed by a decline. The exogenous addition of superoxide dismutase, which is known to dismutate O2•− to H2O2, significantly suppressed the oxidation current. Conclusion Catalytic amperometric measurements were performed using polymeric iron-porphyrin based modified carbon electrode. We claim it to be a useful tool and a direct method for real-time monitoring and precise detection of O2•− in biological samples, with the potential for wide application in plant research for specific and sensitive detection of O2•−.

There is a need for highly efficient photocatalysts, particularly for water purification. In this study, we fabricated a mesoporous TiO2 thin film on a boron-doped diamond (BDD) layer by a surfactant-assisted sol-gel method, in which self-assembled amphiphilic surfactant micelles were used as an organic template. Scanning electron microscopy revealed uniform mesopores, approximately 20 nm in diameter, that were hexagonally packed in the TiO2 thin film. Wide-angle X-ray diffraction and Raman spectroscopy clarified that the framework crystallized in the anatase phase. Current⁻voltage (I⁻V) measurements showed rectification features at the TiO2/BDD heterojunction, confirming that a p⁻n hetero-interface formed. The as-synthesized mesoporous TiO2/BDD worked well as a photocatalyst, even with a small volume of TiO2 (15 mm × 15 mm × c.a. 1.5 µm in thickness). The use of deep UV light (λ = 222 nm) as a light source was necessary to enhance photocatalytic activity, due to photo-excitation occurring in both BDD and TiO2.

Cosensitization by glutathione-protected Au25 clusters on Ru complex, N719-sensitized TiO2 photoelectrodes is demonstrated. Glutathione-protected Au25 clusters showed no significant changes in properties after adsorption onto TiO2 particles, as confirmed by optical absorption spectroscopy, transmission electron microscopy, and laser desorption/ionization mass spectrometry. Adsorption property of the glutathione-protected Au25 clusters depends on the pH, which affects the incident photon-to-current conversion efficiency (IPCE) of the TiO2 photoelectrode containing Au25 clusters. When pH < 5, the IPCE increases with pH. Conversely, the IPCE decreases with pH when pH > 7. The IPCE of a TiO2 photoelectrode sensitized by both glutathione-protected Au25 clusters and N719 was increased compared with photoelectrodes containing either glutathione-protected Au25 clusters or N719, which suggests that glutathione-protected Au25 clusters act as a coadsorbent for N719 on TiO2 photoelectrodes. This is also supported by the results that the IPCE of N719-sensitized TiO2 photoelectrodes increased upon addition of glutathione. Furthermore, cosensitization by glutathione-protected Au25 clusters on N719-sensitized TiO2 photoelectrodes allows that wavelength of photoelectric conversion was extended to the near infrared (NIR) region. These results suggest that glutathione-protected Au25 clusters act not only as a coadsorbent to increase IPCE but also as an NIR-active sensitizer.

Electrochemical detection of glucose was achieved at a glucose oxidase (GOx)-cobalt phthalocyanine (CoPc)-modified boron-doped diamond (BDD) electrode without any additional electron mediator in the electrolyte solution. The surface of the hydrogen-terminated BDD thin film prepared by microwave plasma-assisted CVD was modified with 4-vinylpyridine (4VP) via photochemical modification. The 4VP-BDD was then immersed in a CoPc solution to obtain CoPc-BDD. A poly(p-phenylenediamine) (PPD) thin film containing GOx was coated on the CoPc-BDD electrode surface via electropolymerization. At the GOx/PPD-CoPc-BDD electrode, anodic current for glucose oxidation was observed with a sigmoidal voltammetric curve, indicating successful electron mediation of H2O2 generated as the result of glucose oxidation at GOx. The signal-to-background ratio for voltammetric current of glucose detection was larger at the GOx/PPD-CoPc-BDD electrode than at the GOx/PPD-modified platinum electrode due to the smaller background current of the modified BDD electrode.

A conductive diamond-like carbon (DLC) electrode was prepared by coating a conductive DLC thin film onto a silicon substrate surface using high-power impulse magnetron sputtering (HiPIMS) and ionization deposition methods. The resulting DLC electrode showed a wide potential window of ~3 V. Its background current was slightly larger than that of the borondoped diamond (BDD) electrode and much smaller than that of the glassy carbon electrode, indicating that the DLC electrode has electrochemical properties similar to those of the BDD electrode. Electrochemical measurements in phosphate buffer solution (PBS) containing bovine serum albumin (BSA) did not result in electrode fouling, suggesting that the DLC electrode is suitable for highly sensitive electrochemical measurements in biological fluids. Furthermore, conductive DLC was deposited on the tip of a glass needle to fabricate a DLC microneedle (DLC-MN) electrode with a small tip diameter of 600 nm. The DLC-MN electrode exhibited typical microelectrode behavior and was used to determine ascorbic acid and theophylline in PBS containing BSA. With its small tip diameter and excellent fouling resistance, the DLC-MN electrode holds great promise for facilitating highly sensitive and stable local electrochemical sensing or monitoring in vivo. [ABSTRACT FROM AUTHOR]

According to current research, cancer cell growth is suppressed by ω-3 fatty acids, which are essential fatty acids. On the other hand, ω-3 fatty acids are metabolized to bioactivities in vivo. A systematic evaluation of the ability of ω-3 fatty acids and their metabolites to suppress cancer cell growth has not been sufficiently conducted. Our work evaluated the effect of ω-3 fatty acids (docosahexaenoic acid, eicosapentaenoic acid), trans fatty acid, and the metabolites (Resolvin E1, Maresin 1) on cancer cell growth suppressibility. Our results suggest that there may be optimal fatty acids depending on the kind of cancer cells, the presence or absence of hydroxyl group, and the double bond structure involved. [ABSTRACT FROM AUTHOR]

The electrochemical properties of boron-doped diamond powder (BDDP) were investigated as a step toward its application to aqueous electric double-layer capacitors (EDLCs). Conductive BDDPs (particle size: 150, 350, and 3500 nm) were prepared by depositing a BDD layer on the surface of a diamond powder (DP) core with various particle sizes (100, 300, and 2600 nm) via microwave plasma-assisted chemical vapor deposition. The 150-nm-sized BDDP (BDDP-150) had a relatively large Brunauer-Emmett-Teller (BET) specific surface area (106 m2/g). Cyclic voltammetry of the BDDP electrodes in 1.0MH2SO4 with a symmetric two-electrode system showed an operating voltage of 1.5 V, which is much larger than that of an activated carbon (AC) electrode (0.8 V). In addition, compared to the AC electrode, the BDDP electrodes showed lower capacitance-decrease ratios at fast scan rates. Hence, BDDP-150 had greater energy and power densities than the AC electrode under high rate conditions in the aqueous electrolyte. As the BDDP electrode had a larger bulk density than the AC electrode, aqueous EDLC using BDDP can be expected to be used as a space-saving electric energy storage system suitable for high-speed charging and discharging. [ABSTRACT FROM AUTHOR]

Platinum nanoparticle-supported boron-doped diamond powder (Pt/BDDP) was prepared and investigated as a durable polymer electrolyte fuel cell (PEFC) cathode catalyst. The use of the nanocapsule method enabled dense deposition of Pt nanoparticles (2-5 nm in size) on a boron-doped diamond (BDD) powder <500 nm in size. The Pt/BDDP cathode catalyst showed oxygen reduction reaction activity comparable to Pt-supported carbon black (Pt/C), indicating sufficient conductivity of the BDDP as a catalyst support. Potential cycling in a highly positive potential region (+1.0-+1.5 V vs. NHE) that simulates the start-stop operations of the PEFC was performed to investigate the durability of the Pt/BDDP catalyst. Decreases in the electrochemically active surface area of the Pt/BDDP were suppressed compared to that of Pt/C. Corrosion resistance of BDD against potential cycling was demonstrated by testing a BDD thin-film electrode. The corrosion resistance should be responsible for the improved durability of the BDDP support, possibly by lowering the Pt nanoparticle association process (e.g., agglomeration). [ABSTRACT FROM AUTHOR]

An antithrombogenic electrochemical superoxide anion radical (O2•-) sensor was developed based on the concept of biomimetics. The sensor was fabricated by modification of a carbon microelectrode surface with polymerized iron 5,10,15,20-tetra(3- thienyl)porphyrin (FePor), followed by coating with a polyethylenedioxythiophene (PEDOT)/heparin or PEDOT/carboxymethyl dextran sulfate (CMDS) layer. The antithrombogenic superoxide anion radical sensors exhibited an amperometric oxidation current for O2•-, even after immersion of the sensor in bovine blood for 2 weeks, while the sensor without the PEDOT/heparin (or CMDS) layer had no response current after immersion in bovine blood for 1 h. The response current to 1 µM O2•- was almost constant at the PEDOT/CMDS-FePor-modified electrode after immersion in bovine blood for 1-14 days, and good linearity was observed in the concentration range between 0.52 and 1.80μM, which is suitable sensitivity for the quantitative determination of O2•- in human blood. The PEDOT/CMDS-FePor-modified electrode contains no bio-derived compounds; therefore, its use as an antithrombogenic superoxide anion radical sensor should be safe, even when used in vivo. [ABSTRACT FROM AUTHOR]

Cosensitization by glutathione-protected Au25 clusters on Ru complex, N719-sensitized TiO2 photoelectrodes is demonstrated. Glutathione-protected Au25 clusters showed no significant changes in properties after adsorption onto TiO2 particles, as confirmed by optical absorption spectroscopy, transmission electron microscopy, and laser desorption/ionization mass spectrometry. Adsorption property of the glutathione-protected Au25 clusters depends on the pH, which affects the incident photon-to-current conversion efficiency (IPCE) of the TiO2 photoelectrode containing Au25 clusters. When pH < 5, the IPCE increases with pH. Conversely, the IPCE decreases with pH when pH > 7. The IPCE of a TiO2 photoelectrode sensitized by both glutathioneprotected Au25 clusters and N719 was increased compared with photoelectrodes containing either glutathione-protected Au25 clusters or N719, which suggests that glutathione-protected Au25 clusters act as a coadsorbent for N719 on TiO2 photoelectrodes. This is also supported by the results that the IPCE of N719-sensitized TiO2 photoelectrodes increased upon addition of glutathione. Furthermore, cosensitization by glutathione-protected Au25 clusters on N719-sensitized TiO2 photoelectrodes allows that wavelength of photoelectric conversion was extended to the near infrared (NIR) region. These results suggest that glutathioneprotected Au25 clusters act not only as a coadsorbent to increase IPCE but also as an NIR-active sensitizer. [ABSTRACT FROM AUTHOR]

In this article the novel design of an anticancer drug delivery system is reported based on a pH?sensitive liposome retaining the Fe?porphyrin as a superoxide dismutase(SOD) mimic. The liposomes contained cationic/anionic lipid combinations and were composed of Fe?porphyrin, L???phosphatidylcholine (DMPC), dimethylditetradecylammonium bromide (DTDAB), sodispdum oleate (OANa), and Tween?80. The size of the liposome was approximately 30?nm. The EC50 value (the effective concentration of compound required to produce a 50% lethal dose against cells) of the liposome was found to be significantly smaller than that of cisplatin as the control drug, suggesting that the liposome showed a high cytotoxicity toward the cancer cells. This is due to the fact that the pH?sensitive liposome rapidly corresponds to the acidic environments of the endosomes and is unstable, and the Fe?porphyrin is delivered into the cytosol. This result suggests that O2.? may be useful as a target molecule to induce the selective death of cancer cells and that a pH?sensitive liposome retaining Fe?porphyrin as an SOD mimic is a new class of anticancer agent. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A method based on solid-state diffusion has been developed for the preparation of conductive nanodiamond (ND) powder that should be useful for application as a chemically inert electrode material with a large specific surface area. Heat treatment of a ND/boron powder mixture in H2 atmosphere at 900 °C increased the conductivity from 2.0 x 10-6 to 2.7 10-3 S cm-1. X-ray photoelectron spectroscopy measurements implied that the enhancement of conductivity originated from the solid-state diffusion of boron into ND from the surface. [ABSTRACT FROM AUTHOR]

An electrochemical glucose sensor based on a screen-printed diamond electrode was fabricated as a low-cost, disposable, and sensitive electrode. Amperometric detection of glucose was achieved by using a glucose-oxidase-immobilized cobalt phthalocyanine/boron-doped diamond powder (GOx-CoPc/BDDP)-printed electrode, with a linear calibration curve in the concentration range of 0.21.0mM. The background current for the GOx-CoPc/BDDP-printed electrode stabilized faster than that for the GOx-CoPc/carbon-printed electrode, which confirms its practical usefulness for the detection of glucose at low concentrations. [ABSTRACT FROM AUTHOR]

The article presents a conversation between Kawazoe Makoto, Secretary General of the Tokyo Young Contingent Workers Union (TYCWU) and Head of Labor-Net Japan, and Yuasa Makoto, author and head of the NPO Independent Life Support Center Moyai. Kawazoe talks about the establishment of TYCWU, a labor union whose membership is open to all young people, while Yuasa talks about setting up Moyai, a group that acts as a support center and provides guarantors for people wanting to move into housing. According to Yuasa, when he first got involved in anti-poverty work, from 1995 to 2006, the media did not treat poverty issues seriously. Kawazoe states that labor issues are an important part of the equation and that the labor movement rarely features in the media.

A two-step thermal treatment method was developed for the fabrication of porous conductive boron-doped diamond (BDD) electrodes. The first step involved graphitization of the BDD thin film surface to form a fine microstructure by heating in an argon atmosphere at 1000°C. The second step was removal of the graphitic components by oxidation in air at 425°C. The heat treatment resulted in the formation of dense pores with several tens to several hundred nanometer sizes or smaller on the BDD surface. The pore formation mechanism was discussed by microscopic observation of the (111) and (100) crystal facets on the treated BDD surface. The porous BDD electrode exhibited a double-layer capacitance (Cdl) of ca. 140µFcm-2, which was estimated from cyclic voltammetry (CV) and galvanostatic measurements in an aqueous electrolyte. This Cdl value was approximately 40 times larger than that for the as-deposited BDD electrode, while the potential window remained wide at ca. 3V. [ABSTRACT FROM AUTHOR]

Volcanism at the western margin of the Pacific Ocean has developed above subducting ocean crust, generating island arcs and spreading basins; however, the controls on magmatism at and before the initiation of subduction are less clear. We present new 40Ar/39Ar data from a 1000 km northwest-southeast line of oceanic plateaus on the Philippine Sea plate demonstrating that they formed as a time-progressive volcanic chain mirrored on either side of the West Philippine Basin backarc spreading center. In the north this chain is bounded by a Mesozoic remnant arc, and in the south by subduction beneath the Philippine arc. Geochemically these oceanic plateaus have an EM-2 (enriched mantle 2) ocean island basalt signature matching the older 45-51 Ma volcanic edifices discovered overlapping the remnant arc and intervening basins. The wide distribution of these edifices could mark the first arrival of upwelling mantle, which also mixed with local mid-oceanic-ridge basalt during contemporaneous West Philippine Basin spreading. These features are consistent with the extension and splitting of the Mesozoic arc terrane, driven by regional upwelling centered on the impact of the Oki-Daito mantle plume at 51 Ma. [ABSTRACT FROM AUTHOR]