Spinal cord malignant astrocytomas

Abstract

Coupling a heterogeneous catalytic reaction with a membrane separation can solve the problem concerning catalyst separation in situ from the reaction mixture and make the production process continuous. In this article, the feasibility of continuous hydroxylation of phenol to hydroquinone (HQ) and catechol (CA) over ultrafine TS‐1 catalyst in a submerged ceramic membrane reactor system is investigated. It has demonstrated that the submerged ceramic membrane reactor system can maintain a steady production of HQ and CA, and has a higher productivity than the batch reactor and the fixed‐bed. The effects of operation conditions on the properties of the coupling process are examined by single factor experiments. Results show that the operation conditions influence greatly the conversion, selectivity of phenol hydroxylation, and the filtration resistance. The phenol conversion is above 17% and the dihydroxybenzene (DHB) selectivity keeps at about 90% in a 20 h continuous run under the optimal reaction condition. © 2008 American Institute of Chemical Engineers AIChE J, 2008

Prognostic factors in intramedullary astrocytomas: a literature review

“…Results of a statistical analysis of age as a prognostic factor were reported in 15 studies [2,5,24,27,28,30,34,41,46,49,56,59,60,64,65] (Table 4). Of these, 13 were classified as category A, 8 failed to find a significant relationship between age and prognosis [2,24,28,30,34,46,56,59], as did one additional category B study [27].…”

“…Contrary to these four reports, the last category A study [49] reported age over 20 to be associated with increased survival. In addition, one category B study dealing exclusively with malignant astrocytomas reported advanced age to decrease median survival [65].…”

“…Of these, nine were classified as category A, six failed to find a significant association between gender and prognosis [2,34,41,49,59,60], as did two additional category B studies [27,65]. Two category A [5].…”

“…Results for EOR specifically for HG histology were reported in nine studies, four were classified as category A [5,15,34,46], five as category B [11,27,51,52,65] (Table 13, lower part). Only one category A study reported increased 4-year OS in anaplastic astrocytoma (grade III) patients [46]; those receiving GTR had significantly improved survival (78% at 5 years) when compared to patients with STR (38% at 5 years, p = 0.028).…”

“…On the other hand, high-grade (HG) tumors, e.g. anaplastic astrocytomas (WHO grade III) and intramedullary glioblastomas (WHO grade IV), together account for approximately 8-13% of intramedullary tumors of astrocytic origin [7,29,65,68] and are usually characterized by rapid progression.…”