ELECTROPHORETIC DEPOSITION OF METAL-PHTHALOCYANINE AS A HIGH- PERFORMANCE ELECTROCATALYST

Metal-phthalocyanines (MPc) has high chemical stability and high catalytic activities in electrochemical reactions such as oxygen reduction reaction (ORR), CO2 reduction, and so on. It has becoming known that the catalytic activity of MPc should depend on the crystal structures, i.e., alfa-type MPc gives higher activity than other phases. In this study, the alfa-structure controlled MPcs could successfully be prepared by an electrophoretic deposition (EPD) method on gas diffusion type carbon electrode (GDE) as an electrocatalyst. Double layered MPcs electrocatalyst prepared by EPD also gave high performance for ORR. MPc (M: Li, Mg, Mn, Fe, Co, Ni, Cu, Zn, Ag, Sn, Pb) was dissolved in dichloromethane solution with trifluoroacetic acid was used for EPD method at room temperature. GDE and Pt counter electrode were used EPD (DC: +40 - +100V, 1-10min). Crystal structures of the MPcs were investigated by XRD, UV-vis, SEM, FT-IR, etc. ORR properties were evaluated in a half-cell in 1M H2SO4 at 70°C with a potentiostat using reversible hydrogen electrode (RHE) and Pt plate as reference and counter electrodes, respectively. Most of the alfa-phase MPcs could be prepared by the EPD on GDEs using dichloromethane solution containing trifluoroacetic acid. However, MPcs (M=Li, Mg) couldn’t prepared by the same condition. Alfa-phase MPc doped GDE showed higher ORR activity than that of GDE loaded with beta-MPc. In the cathodic performance at 0.4 V vs. RHE (I0.4) and open circuit potential (Eocp) at 70ºC of gas-diffusion electrodes loaded with various alfa-MPc catalysts deposited by EPD method. The GDEs loaded with alfa-MPcs showed various open circuit potentials, depending on the central metal (M) of alfa-MPc. GDE loaded with alfa-FePc showed the highest open circuit potential among the alfa-MPcs. This indicates that alfa-FePc could produce effect on density of adsorbed oxygen in the catalytic layer in the GDE. Moreover alfa-FePc based electrode showed high activity even at lower overpotential range, in spite of its low activity at higher overpotential range. The change in the Tafel slops was observed which indicates the change in the mechanism of ORR. Tafel slope of -43mV/decade at lower overpotential range shows the oxygen reduction reaction route with the formation of peroxo species in which the hydrogenation desorption reaction is rapid. While, the higher overpotential the Tafel slope of -222mV/decade might show the route which the peroxo species are not formed, like the H2O2 formation route. On the other hand, the Tafel slope of the GDE loaded with alfa-CoPc was not changed in the wide overpotential range. Also, the alfa-CoPc could keep the catalytic activity for several cycles of measurements of cathodic polarization curves, while that of alfa-FePc changed in the cycles. The decrease in ORR cycle for alfa-FePc seems to be come from the large strength of oxygen adsorption of alfa-FePc. On the other hand, CoPc/FePc double layered electrocatalyst prepared by the EPD gave more higher performance for ORR and stability. Acknowledgment: This work was partially supported by the Grant from JST ACT-C and JSPS KAKENHI Grant Number 25410240

Gefitinib, an epidermal growth factor receptor blockade agent, shows additional or synergistic effects on the radiosensitivity of esophageal cancer cells in vitro.

Human esophageal cancers have been shown to express high levels of epidermal growth factor receptor (EGFR) and a relationship between high EGFR expression and local advance, the number of lymph node metastases, life expectancy, and sensitivity to chemo-radiotherapy has been demonstrated. We examined the use of gefitinib, an orally active EGFR-selective tyrosine kinase inhibitor, as a new strategy for treatment of esophageal carcinoma. The effects of gefitinib were evaluated in monotherapy and in combination with radiotherapy in human esophageal carcinoma cell lines. Gefitinib produced a dose-dependent inhibition of cellular proliferation in all of the 8 esophageal carcinoma cell lines examined, with IC50 values ranging from 5.7 microM to 36.9 microM. In combination, gefitinib and radiotherapy showed a synergistic effect in 2 human esophageal carcinoma cell lines and an additive effect in 5 cell lines. Western blotting demonstrated that gefitinib blocked activation of the EGFR-extracellular signal-regulated kinase (Erk) pathway and the EGFR-phosphoinositide-3 kinase (PI3K)-Akt pathway after irradiation. These results suggest that further evaluation of EGFR blockade as a treatment for esophageal cancer should be performed, and that radiotherapy combined with EGFR blockade may enhance the response of esophageal carcinoma to therapy.</p

Dusty ERO Search behind Two Massive Clusters

We performed deep K'-band imaging observations of 2 massive clusters, MS 0451.6-0305 at z = 0.55 and MS 0440.5+0204 at z = 0.19, for searching counterparts of the faint sub-mm sources behind these clusters, which would provide one of the deepest extremely red object(ERO) samples. Comparing our near-infrared images with optical images taken by the Hubble Space Telescope and by the Subaru Telescope, we identified 13 EROs in these fields. The sky distributions of EROs are consistent with the previous results, that there is a sign of strong clustering among detected EROs. Also, the surface density with corrected lensing amplification factors in both clusters are in good agreement with that derived from previous surveys. We found 7 EROs and 3 additional very red objects in a small area (\sim 0.6 arcmin^2) of the MS 0451.6-0305 field around an extended SCUBA source. Many of their optical and near-infrared colors are consistent with dusty star-forming galaxies at high redshifts(z \sim 1.0-4.0), and they may be constituting a cluster of dusty starburst galaxies and/or lensed star-forming galaxies at high redshift. Their red J-K' colors and faint optical magnitudes suggest they are relatively old massive stellar systems with ages(>300 Mega years) suffering from dust obscuration. We also found a surface-density enhancement of EROs around the SCUBA source in the MS 0440.5+0204 field.Comment: 19 pages, 11 figures, Latex(using pasj00.cls). To be published in PASJ vol 55, No. 4(Aug 2003

Biodecolourisation of acid red 27 Dye by Citrobacter freundii A1 and Enterococcus casseliflavus C1 bacterial consortium

The feasibility of Citrobacter freundii A1 and Enterococcus casseliflavus C1 bacterial consortium under sequential facultative anaerobic-aerobic treatment for complete dye degradation using AR-27 dyes shows 98% decolourisation and 100% COD removal after 72 hours treatment. Moreover, the UV-Vis spectroscopy and Fourier Transform Infrared (FTIR) Spectroscopic analysis confirmed that the azo linkage was cleaved after the decolourisation occurred. While, the cyclic voltammetry analysis also shows that the decolourisation of AR-27 by C. Freundii A1 and E. Casseliflavus C1 was an irreversible reaction and the detection of oxidation reaction under agitation proved the presences of AR-27 degradation process. Furthermore, the HPLC analysis has confirmed the AR-27 degradation through the decrease in catechol concentration

Photoelectrochemical reduction of CO2 using a TiO2 photoanode and a gas diffusion electrode modified with a metal phthalocyanine catalyst

The mass transport limitations encountered in classical H-cells for electrochemical CO2 reduction reaction (CO2RR) have spurred research in gas diffusion electrode (GDE) systems. However, current reports on CO2RR required large biases (anode potential vs. cathode potential > -2.0 V) for high current efficiencies. In this work, we combined a TiO2 photoanode and a GDE modified with a Co, Ni or Sn metal phthalocyanine (MPc) catalyst to reduce the external bias requirement for CO2RR. We found the Faradaic efficiencies and the selectivity of the photoelectrolysis products were influenced by (i) the metal cation (Ni, Co or Sn) coordinated to the phthalocyanine, (ii) the electrolyte temperature and concentration and (iii) the magnitude of the applied bias. In addition, analyzes of the voltage distributions between the TiO2 photoanode and the MPc-GDE revealed the current efficiency of the TiO2/MPc-GDE cell was limited predominantly by a high ohmic polarization loss at the TiO2 photoanode due to an excessive thickness of the TiO2 layer. The cathodic process at the MPc-GDE was governed by the activation energy of the electrode. The thickness of the TiO2 photoanode was subsequently optimized for higher current efficiency. The highest Faradaic efficiency for PEC CO2RR was obtained when a NiPc catalyst was utilized as the CO2RR catalyst and the optimum cell conditions were as follows: (i) a GDE electrolyte temperature of 1 M aq. Na2SO4 electrolyte solution and (iii) a TiO2 oxidation time of 3 h. Using these optimized cell conditions and under UV illumination, the as-prepared TiO2/NiPc-GDE cell shows a notably high CO2RR Faradaic efficiency and selectivity for CO (at 98%) and at a lowest reported cell bias of 0.8 V (anode potential vs cathode potential). This work provides an improved understanding of the cell designs of a vapor-fed CO2RR reactor based on a TiO2/MPc-GDE photoelectrochemical system

Human pulmonary dirofilariasis presenting as a small nodule with a cavity

A 73-year-old woman had a 4-year history of lung fibrosis from collagen vascular disease. She presented with a complaint of dry cough. A chest radiograph showed a 2-cm solitary pulmonary nodule with a small cavity in the right lower lobe. Preoperatively, we performed computed tomography of the chest and measured tumor markers. Video-assisted thoracotomy was performed because we could not rule out lung cancer. Pathologic analysis confirmed the presence of a granuloma with Dirofilaria immitis. In Japan, the incidence of human dirofilariasis has steadily increased and must be considered in the workup of cavitary pulmonary nodules