62 research outputs found

    Dihydroxylation of Naphthalene by Molecular Oxygen and Water Using TiO2 Photocatalysts

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    TiO2-catalyzed photo-reaction of naphthalene was investigated in mixed solutions of acetonitrile and water. The main products were confirmed to be 1,8- and 1,3-dihydroxynaphthalene, without any 1- or 2-naphthol being detected. Both O2 and H2O were essential to yield the products. The quantum efficiency of the 1,8- and 1,3-dihydroxynaphthalene products reached about 10% at 365 nm after irradiated for 1 h

    New approach for synthesis of activated carbon from bamboo

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    Unconventional pretreatment, that is, delignification and the addition of guanidine phosphate, was performed for the synthesis of activated carbon having a high specific surface area from bamboo by physical activation. The values of the specific surface area, total pore volume, and average pore size depended on the amount of added guanidine phosphate and the CO2 activation time. The amount of the added guanidine phosphate under the optimum conditions for the highest specific surface area was much lower than that of the phosphorous acid chemical activator under conventional conditions. The N2 adsorption isotherms of all the samples were type I, which means that micropores were dominant. The pore sizes of the samples in this study were similar to that of the physically-activated carbon. Therefore, the activation process was presumed to be essentially not chemical, but physical. The relation between the yield and the specific surface area improved with the addition of guanidine phosphate. The reason for the improvement may be the change in the reactivity of the carbon material generated during the heating process. The maximum specific surface area was ca. 2000 m2 g−1, which is a high value for a physically-activated carbon

    TiO2-Photocatalyzed Epoxidation of 1-Decene by H2O2 under Visible Light

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    1-Decene was converted to 1,2-epoxydecane on UV-irradiated TiO2 powder using molecular oxygen as the oxygen source. Other main products were nonanal and 2-decanone. For anatase-form TiO2 powders, the reaction rate was hardly affected by addition of hydrogen peroxide to the solution. In contrast, for rutile-form TiO2 powders, the rate of epoxide generation was significantly increased by addition of hydrogen peroxide. In this case, the reaction occurred under visible light as well as UV light. The selectivity of the production of 1,2-epoxydecane was higher under visible light than under UV light. The conversion efficiency of an incident photon to 1,2-epoxydecane was about 2% when irradiated with visible light in the range 440–480 nm. UV–visible diffuse reflection spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy suggested the generation of a Ti–η2-peroxide on rutile TiO2 surface after treatment with hydrogen peroxide. The initial step of the reaction under visible light was attributed to a photochemical reaction of this peroxide with 1-decene

    Improvement of selectivity for CO2 reduction by using Cu2ZnSnS4 electrodes modified with different buffer layers (CdS and In2S3) under visible light irradiation

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    Cu2ZnSnS4 (CZTS) electrodes modified with different n-type buffer layers (CdS and In2S3) were used as photocathodes for CO2 reduction under visible light irradiation (420 < λ < 800 nm) in aqueous media. Compared to a bare CZTS electrode, CZTS electrodes modified with n-type buffer layers (CdS and In2S3), by which a p–n heterojunction between CZTS and the n-type buffer layer is formed, showed a significant increase in the photocurrent assigned to CO2 reduction. In addition, product selectivity of CO2 reduction was improved by surface modification with an n-type buffer layer: that is, selective CO2 reduction into CO was achieved by using a CdS/CZTS electrode, while HCOOH selectivity was observed over an In2S3/CZTS electrode. In this study, we investigated the photoelectrochemical properties of CZTS electrodes modified with n-type buffer layers (CdS and In2S3) in conjunction with the structural and optical properties, and we investigated their activity for PEC CO2 reduction

    Prognostic Impact of Pre- and Post-operative P-CRP Levels in Pancreatic Cancer Patients

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    Background: C-reactive protein (CRP) levels reflect ongoing inflammation and/or tissue damage, and studies suggest that platelets play a role in tumor invasion and metastasis. P-CRP is defined as the multiplied product of serum CRP and platelet levels. Here the prognostic value of pre- and post-operative P-CRP levels in pancreatic cancer (PC) patients was assessed. Methods: This retrospective study used data from 107 consecutive PC patients who had undergone either pancreaticoduodenectomy or distal pancreatectomy. Clinicopathological parameters and pre/post-operative laboratory data derived from patient records were used for analyses. P-CRP was defined as the product of peripheral thrombocyte count (/uL) × serum CRP level (mg/dL) divided by 104; the optimal P-CRP cut-off value was defined using receiver operating characteristic curves. Results: PC patients were classified as either P-CRPLow (< 1.782; n = 49) or P-CRPHigh (≥ 1.782; n = 58), based on the cut-off value of 1.782. Univariate analysis revealed that performance status, clinical stage, pathological T and N stages, P-CRP, and carbohydrate antigen 19-9 (CA19-9) significantly affected overall survival (OS). Multivariate analysis revealed that independent risk factors for OS were pathological N stage, P-CRP, and CA19-9. Additionally, 103 PC patients for whom postoperative data were available were classified into four groups (P-CRPLow-Down, P-CRPLow-Up, P-CRPHigh-Down and P-CRPHigh-Up), based on preoperative P-CRP and postoperative trend of P-CRP, and we found that prognosis, in terms of OS, was significantly different among these groups (P = 0.012). Conclusion: Pre- and post-operative P-CRP values are a potential predictor of prognosis in PC patients

    Utility and Limitation of Preoperative Neutrophil Lymphocyte Ratio as a Prognostic Factor in Hepatocellular Carcinoma

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    【Background】 The neutrophil lymphocyte ratio (NLR) has been proposed to be a surrogate marker of inflammation and immunological status and to have prognostic value in various malignancies. This study was conducted to clarify the prognostic significance of preoperative NLR in hepatocellular carcinoma (HCC). 【Methods】 We enrolled 135 patients with histologicallyproven HCC who underwent initial curative hepatectomy. Based on the median NLR values, patients were divided into: NLR ? 2.0 (NLR-high, n = 69) and NLR < 2.0 (NLR-low, n = 66). 【Results】 In univariate analysis, the 5-year overall survival (OS) rates were 59.8 % ± 6.7% and 75.6% ± 6.5% (P = 0.028) in the NLR-high and NLR-low groups, respectively. Furthermore, the 5-year disease specific survival rates were 68.6% ± 6.7%, and 81.2 ± 6.4% (P = 0.048) in the NLR-high and NLR-low groups, respectively. 【Conclusion】 Our results showed that high NLR was an independent predictor for OS in hepatectomy-treated HCC, suggesting that NLR may be a novel prognostic biomarker for HCC. On the other hand, NLR also has a limitation to predict postoperative prognosis of HCC patients by itself
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