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The origin of the cobalt particle size effects in Fischer-Tropsch (FT) catalysis is analyzed. The lower surface-specific activity (TOF) of Co particles is caused by both blocking of edge/corner sites and a lower intrinsic activity at the small terraces and the higher methane selectivity of small Co particles is brought about by their hydrogen coverages.

Introduction Liver metastases are common in patients with gastrointestinal stromal tumors (GIST). In the absence of randomized controlled clinical trials, the effectiveness of surgery as a treatment modality is unclear. This study identifies safety and outcome in a nationwide study of all patients who underwent resection of liver metastases from GIST. Methods Patients were included using the national registry of histo- and cytopathology (PALGA) of the Netherlands from 1999. Kaplan Meier survival analysis was used for calculating survival outcome. Univariate and multivariate regression analyses were carried out for the assessment of potential prognostic factors. Results A total of 48 patients (29 male, 19 female) with a median age of 58 (range 28–81) years were identified. Preoperative and postoperative tyrosine kinase inhibitor therapy was given to 30 (63%) and 36 (75%) patients, respectively. A minor liver resection was performed in 32 patients, 16 patients underwent major liver resection. Median follow-up was 27 (range 1–146) months. Median progression-free survival (PFS) was 28 (range 1–121) months. One-, three-, and five-year PFS was 93%, 67%, and 59% respectively. Median overall survival (OS) was 90 (range 1–146) months from surgery. The one-, three-, and five-year OS was 93%, 80%, and 76% respectively. R0 resection was the only independent significant prognostic factor for DFS and OS at multivariate analysis. Conclusion Resection of liver metastases in GIST patients combined with imatinib may be associated with prolonged overall survival when a complete resection is achieved. [ABSTRACT FROM AUTHOR]

Abstract. A survey is presented of the storage capacities of a large number of different adsorbents for hydrogen at 77 K and I bar. Results are evaluated to examine the feasibility and perspectives of transportable and reversible storage systems based on physisorption of hydrogen on adsorbents. It is concluded that microporous adsorbents, e.g. zeolites and activated carbons, display appreciable sorption capacities. Based on their micropore volume (Is similar to 1 ml/g) carbon-based sorbents display the largest adsorption, viz. 238 ml (STP)/g, at the prevailing conditions. Optimization of sorbent and adsorption conditions is expected to lead to adsorption of Is similar to 560 mi (STP)/g, close to targets set for mobile applications. [ABSTRACT FROM AUTHOR]

B Background: b Hepatocellular adenoma (HCA) is regarded as a rare complication of long term use of oral contraceptive pills (OCP). Our aim was to study the epidemiology and behavior of HCA after OCP cessation as longitudinal data are scarce. B Conclusion: b In our cohort the incidence of OCP use in patients with HCA was 68%, of which 39% went into regression after OCP cessation. [Extracted from the article]

[Display omitted] • Melt infiltration allows preparation of high loading supported silver catalysts. • Silver nitrate enters mesoporous silica upon melting. • Control over shape silver by tuning precursor decomposition parameters. • Silver nanowires very active and selective in cinnamaldehyde hydrogenation. Heterogeneous supported catalysts are often synthesized by impregnation or precipitation methods. Recently, melt infiltration has emerged as an alternative method that allows high metal loadings and eliminates the need for a solvent, but challenges arise regarding control over the particle size and distribution. In this work, melt infiltration for the synthesis of supported silver catalysts is explored. The narrow pore size distribution of the chosen ordered mesoporous silica support, SBA-15, allowed in depth in-situ and ex-situ characterization of the infiltration of the precursor, molten silver nitrate, into the support and its subsequent decomposition to form metallic silver nanowires or nanoparticles. The heat treatment parameters during decomposition played a key role in determining whether nanowires or nanoparticles were formed. The supported silver catalysts containing high silver weight loadings were investigated in the selective hydrogenation of cinnamaldehyde, where the silver nanowires showed superior activity and selectivity over the nanoparticles. Hence, melt infiltration shows great promise for the synthesis of supported silver catalysts containing high silver weight loadings, which are applicable in, e.g., selective oxidation or hydrogenation reactions. [ABSTRACT FROM AUTHOR]

[Display omitted] • DME is a valuable chemical and fuel that can be directly obtained from synthesis gas. • Nb2O5· n H2O and NbOPO4 with a Cu-based catalyst are highly active for DME synthesis. • Nb-based catalysts show high vol.-based activity due to high acid site concentration. • Cu migration to the Nb-based materials might have caused activity loss. The production of dimethyl ether (DME) as compared to methanol from synthesis gas allows for increased conversions in a single pass. A challenge in this process is the combination of methanol synthesis and dehydration functionalities in a single catalyst without mutual negative interference of their performances. Here, we studied the use of hydrated niobium pentoxide (Nb 2 O 5 · n H 2 O) and niobium phosphate (NbOPO 4) in combination with a copper-based methanol synthesis catalyst in the direct synthesis of DME, while gamma-alumina (γ-Al 2 O 3) was used as a reference material. The three solid acids combined with the copper-based catalyst proved active and selective in the production of DME, however all of them showed some degree of deactivation throughout the reaction. Characterization of the used catalysts pointed out that while the γ-Al 2 O 3 -based mixture deactivated most likely due to coke deposition on the alumina and structural changes in the methanol synthesis catalysts, the Nb 2 O 5 · n H 2 O and NbOPO 4 -based catalysts lost activity probably as a result of copper migration from the methanol synthesis catalyst to the acid component. In view of the high volume-based activity of the Nb-based solid acids it is concluded that these are promising components for the direct catalytic conversion of synthesis gas to DME. [ABSTRACT FROM AUTHOR]