Enhanced activity and stability of Zr-promoted Pd/HZSM-5 catalyst for low-temperature methane combustion

A Zr-promoted Pd/HZSM-5 catalyst, prepared by an impregnation method, was found to possess high catalytic activity as well as thermal and hydrothermal stability for low-temperature methane combustion

Endocrinologic, neurologic, and visual morbidity after treatment for craniopharyngioma

Craniopharyngiomas are locally aggressive tumors which typically are focused in the sellar and suprasellar region near a number of critical neural and vascular structures mediating endocrinologic, behavioral, and visual functions. The present study aims to summarize and compare the published literature regarding morbidity resulting from treatment of craniopharyngioma. We performed a comprehensive search of the published English language literature to identify studies publishing outcome data of patients undergoing surgery for craniopharyngioma. Comparisons of the rates of endocrine, vascular, neurological, and visual complications were performed using Pearson’s chi-squared test, and covariates of interest were fitted into a multivariate logistic regression model. In our data set, 540 patients underwent surgical resection of their tumor. 138 patients received biopsy alone followed by some form of radiotherapy. Mean overall follow-up for all patients in these studies was 54 ± 1.8 months. The overall rate of new endocrinopathy for all patients undergoing surgical resection of their mass was 37% (95% CI = 33–41). Patients receiving GTR had over 2.5 times the rate of developing at least one endocrinopathy compared to patients receiving STR alone or STR + XRT (52 vs. 19 vs. 20%, χ2P < 0.00001). On multivariate analysis, GTR conferred a significant increase in the risk of endocrinopathy compared to STR + XRT (OR = 3.45, 95% CI = 2.05–5.81, P < 0.00001), after controlling for study size and the presence of significant hypothalamic involvement. There was a statistical trend towards worse visual outcomes in patients receiving XRT after STR compared to GTR or STR alone (GTR = 3.5% vs. STR 2.1% vs. STR + XRT 6.4%, P = 0.11). Given the difficulty in obtaining class 1 data regarding the treatment of this tumor, this study can serve as an estimate of expected outcomes for these patients, and guide decision making until these data are available

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Catalytic combustion of methane over PdO supported on Mg-modified alumina

Mg-modified alumina supports were prepared in both impregnation and co-precipitation routes, and Pd catalyst was finally obtained by incipient wetness method. Catalysts supported on different oxides were characterized by means of conventional techniques like XRD, laser Raman, CO-pulse, N-2-adsorption, etc. It was demonstrated that dispersion of Pd component on unit BET surface area increased and PdO active phase crystallized well on account of the formation of MgAl2O4 spinel. Combined with temperature programmed reaction techniques (O-2-TPD, CH4-TPR, H-2-TPSR), three kinds of PdO species were identified on spinel support. Moreover, a moderate interaction between MgAl2O4 spinel oxide support and PdO was discovered and an epitaxy formation mechanism of the crystalline PdO species was suggested. For this novel PdO species satisfied the requirement of structural particularity for reaction with methane, it could serve as the active phase for methane combustion. As a result, prominent improvement on ignition performance was observed in following catalytic activity test. (C) 2002 Elsevier Science B.V. All rights reserved

Promotion effects of ZrO2 on the Pd/HZSM-5 catalyst for low-temperature catalytic combustion of methane

Palladium catalysts supported on the carrier of HZSM-5 (Si/Al-2 = 50), without and with additives of oxides of Zr, Zn, Cu, La, Ba, Fe, Mn, Ca, Mg and Li, were prepared by the impregnation method and investigated as catalysts for low-temperature methane oxidation. The catalysts were characterized by various techniques, including XRD, N-2-BET, O-2-TPD and CH4-TPR. Among the additives investigated, ZrO2 was found to be a good promoter for the catalytic activity and stability of the palladium catalysts. The temperatures for methane ignition (T-10%) and total conversion (T-100%) of Pd-Zr/HZSM-5 were found to be 25 and 55 degreesC lower than those of Pd/HZSM-5, respectively. Besides, the O-2-TPD and CH4-TPR results indicated that the temperatures for O-2 desorption and reduction by methane of the catalysts decreased with increasing catalytic activities. Therefore, the presence of more reactive PdOx (x > 0) species on Pd-Zr/HZSM-5 is suggested as the main reason for its remarkably promoted activity. Although deactivation did occur slightly in the presence of water vapor (4 vol.%), the Pd-Zr/HZSM-5 catalyst is thought to be promising for practical applications due to its superior activity for methane total conversion and excellent thermal stability. (C) 2002 Elsevier Science B.V. All rights reserved