Search

Titanium-supported electrocatalysts composed of novel metal oxides have exclusively been utilized as anodes in the cathodic protection (CP) of steel structures. These types of anodes have a small overpotential toward the chlorine evolution reaction (CER) in impressed-current cathodic protection (ICCP) systems and vigorously evolve chlorine (Cl2) in electrolytes containing Cl−, such as seawater. Cl2 has a negative impact on the ecosystem because of its intrinsic toxicity and corrosivity. We present herein a thin film coating that can effectively suppress the CER without prevention of the oxygen evolution reaction (OER) at the underlying iridium oxide (IrO2) layer coated on a titanium substrate in 0.5 M NaCl solution. The thin film consists of buserite-type layered manganese dioxide (MnO2), the interlayer of which accommodates Mg2+ cations and two layers of H2O molecules, and is uniformly deposited via an electrochemical route and subsequent ion-exchange. The CER efficiency of the electrode modified with the Mg-buserite layer was as small as 11% at + 1.7 V vs. Ag/AgCl.

We have fabricated a thin film of multilayered MnO2 whose interlayer is occupied with hexadecylpyridinium (HDPy) cations, using a simple anodic approach. The resulting film can effectively sorb iodide anions from aqueous solutions, even in the presence of NaCl or Na2SO4. The maximum sorption capacity was estimated to be 256 mg/g-MnO2, whereas a layered MnO2 film intercalated with K(+) ions showed no significant sorption. The layered structure of the HDPy/MnO2 composite remained unchanged after a sorption experiment. This indicates the incorporation of I(-) ions between MnO2 layers due to their specific affinity toward HDPy.

Identification of specific signaling pathways for cardiac hypertrophy in living animals is challenging because no methods have been established to directly observe sequential molecular signaling events at the transcriptional level during pathogenesis. Here, our aim was to develop a useful method for monitoring the specific signaling pathways involved in the development of cardiac hypertrophy in vivo. Expression profiling of the left ventricle by microarray was performed in 2 different mouse models of cardiac hypertrophy: mechanical pressure overload by transverse aortic constriction (TAC) and neurohumoral activation by angiotensin II (Ang II) infusion. To annotate the information on transcription factor-binding sites, we collected promoter sequences and identified significantly frequent transcription factor-binding sites in the promoter regions of coregulated genes from both models (P < 0.05, binomial probability). Finally, we injected a firefly luciferase vector plasmid containing each transcription factor-binding site into the left ventricle in both models. In the TAC and Ang II models, we selected 379 and 12 upregulated genes, respectively. Twenty binding sites for transcription factors, including activator protein 4, were identified in the TAC model, and 4 sites for transcription factors, including ecotropic viral integration 1, were identified in the Ang II model. GATA-binding sites were noted in both models of cardiac hypertrophy. Using the firefly luciferase reporter, we demonstrated the enhancement of transcriptional activity during the progression of cardiac hypertrophy using in vivo imaging in live mice. These results suggested that our approach was useful for the identification of unique transcription factors that characterize different models of cardiac hypertrophy in vivo.

Reactions of metallurgical-grade silicon (MG-Si) with gaseous hydrogen bromide (HBr) has been monitored by means of online gas chromatography in a flow reactor system. The formation of tri-bromosilane started to occur at 380 °C, accompanied by the consumption of HBr. The conversion of HBr into bromosilanes increased with an increase in reaction temperature and reached a maximum at 440 °C. An increase of the HBr concentration in a HBr-N2 mixed gas led to an increase in the consumption of MG-Si, while it reduced the selectivity of the tri-bromosilane formation. An increase in total flow rate of the reaction gas caused a dramatic decrease in the HBr conversion and enhanced the selectivity of the tri-bromosilane formation. The rate constant for overall bromination reaction at 400 °C was measured to be 0.46 s−1. Concentrations of impurities in the product were much less than those in MG-Si. Moreover, kerf loss silicon was subjected to the bromination reaction under the optimized conditions.

Multilayered manganese oxide films were prepared on a platinum electrode by potentiostatic oxidation of aqueous Mn2+ ions in the presence of n-tetra-alkylammonium compounds. Alkylammonium cations were intercalated between manganese oxide layers to balance the negative layer charge. Effects of several preparative parameters such as the size of alkylammonium molecules, counteranions, and bath composition on the structure of products were investigated. The interlayer distance of the products increased with increasing alkyl chain length up to C4, and the change became obviously small among C4–C6 compounds. The multilayer formation was achieved only when the manganese concentration was lower than 10 mM, and the highest crystallinity was obtained from a bath composed of 2 mM manganese sulfate and 50 mM alkylammonium chloride. At low concentrations of alkylammonium (2+ with H2O.

We report a case of a 41-year-old woman who underwent therapeutic embolization of an aberrant systemic artery of the lung. Except for chest pains immediately after embolization, she recovered well and has not experienced hemoptysis in the past 6 years. In such patients, coil embolization could be an alternative choice of treatment, with the expectation of an excellent long-term result despite ischemia of the corresponding lung parenchyma.

Thin films of mixed manganese (mainly 4+) and vanadium (5+) oxides deposited electrochemically on a platinum substrate have been heat-treated under vacuum at various temperatures between 25 and 400 °C. Electron spin resonance and x-ray photoelectron spectroscopy revealed that the reductive formation of Mn2+ occurs at 300 °C only in the presence of vanadium within the film. This phenomenon can be regarded as a result of electron transfer from V4+ ions generated thermally to neighboring Mn sites. Voltammetric response of the heat-treated Mn/V oxide film in borate solution was enhanced with increasing the number of potential cycles, and the steady-state current was much larger than that of pure manganese oxide. Vanadate ions were diffused from the film to maintain the charge balance during the repetition cycles. The resultant porous structure can allow easier mass transport of protons to electrically conductive Mn oxide surface, offering the improved charge–discharge performance of the electrode.

A thin film of mixed manganese and vanadium oxides was formed on a platinum electrode by electro-oxidation of Mn2+ precursors in aqueous solution with VO3−. X-ray analysis revealed that the film consists of an amorphous phase including trivalent and tetravalent Mn ions. The infrared spectrum exhibited the bands attributable to V2O5, suggesting that protonation and dehydration of VO3− occur to form the polymeric structure. The mixed oxide film showed no electron spin resonance signal in an as-deposited state. After the film-coated electrode was immersed into water and then dehydrated, however, a characteristic signal (g = 2.022) of Mn2+ in the solid phase appeared, accompanying a decrease in the vanadium content. This suggests that Mn3+ ions not in the oxide network, but pairing with unreacted VO3−, are disproportionated to MnO and MnO2 by the reaction with water, while the VO3− is diffused to keep the charge valance of the film.

Molybdenum-containing films electrochemically deposited from an aqueous solution of 12-molybdphosphate (PMo12O40)3− (denoted as PMo12) have been characterized by x-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), and electron spin resonance (ESR) techniques. XPS and FTIR data indicate that electrolysis of PMo12 leads to the formation of Mo–O–Mo linkage by condensation of the polyanions accompanied by decomposition of the phosphate moiety. The ESR spectrum of the deposited film exhibits an asymmetric signal with g ∼1.92, indicative of pentavalent molybdenum (d1). The feature of this signal is close to that for a MoV ion in the amorphous MoO3 phase, but not in the PMo12 framework. It is therefore suggested that the deposited film no longer has the Keggin structure PMo12, but consists of a continuous structure containing molybdenum oxide.

Self-assembled monolayers consisting of 3,3′-thiodipropionic acid and n-decyl mercaptan formed on gold electrodes have been studied for sensitive and selective determination of Cu2+ and Ag+ ions. The monolayers were found to provide both superior sensitivities and stabilities even in the presence of protein. Various factors, such as solution pH and concentration time, were optimized to obtain detection limits of 2×10-9 M and 6×10-8 M for Cu2+ and Ag+ ions at an S/N ratio of 2 by linear-sweep anodic stripping voltammetry. In the presence of albumin, the currents of the modified electrode, 1.75 times as great as those for the bare electrode, show a significant performance improvement over the previously reported cellulose coated electrode (1.13 times). One of the main advantages of using this electrode is an excellent antifouling activity against protein adsorption, coupled with highly selective metal-ion suppression/concentration capabilities, which can be attained without using a mercury film for preconcentration.

The electrochemical polymerization of aniline on a platinum electrode in aqueous HClO4 and H2SO4 solutions has been studied by means of in situ Fourier-transform infrared (FTIR) reflection spectroscopy. The spectra, taken at early stage of the polymerization in both solutions, exhibited the absorption characteristic of polyaniline (PAn) in an emeraldine state, even at a highly positive potential (≥+0.7 V vs. Ag/AgCl (saturated KCl)). Polymer growth in H2SO4 was accompanied by an increase in the molar ratio of [HSO4-]/[SO42-], indicating that the protons generated during the oxidation of aniline react with SO42- to afford HSO4-, and that polymer growth is facilitated. In contrast, such proton-scavenging behavior was not observed in a HClO4 solution, and the growth of PAn was suppressed owing to the accumulation of protons. Under the condition that aniline was extremely consumed, the produced PAn was subjected to oxidative degradation, which was competitive with the growth process of PAn. The major degradation species was identified to be p-benzoquinone.