Aminoiron(III)–porphyrin–alumina catalyst obtained by non-hydrolytic sol-gel process for heterogeneous oxidation of hydrocarbons

An aminoiron(III) porphyrin immobilized on an alumina matrix was prepared and used as catalyst for the oxidation of organic substrates. Powder alumina had been prepared by a non-hydrolytic sol-gel method through condensation of aluminum chloride with anhydrous ethanol. Then, iron(III) [5,10,15,20-tetrakis(2,6-dichloro-3-aminophenyl)-porphyrin] was immobilized on the alumina powder under magnetic stirring, reflux, and inert atmosphere. Ultraviolet–visible and infrared spectroscopies, powder X-ray diffraction, scanning electron microscopy and thermal analysis were applied for characterizing the resulting material, confirming that the ironporphyrin was immobilized on the alumina support. The catalytic activity of ironporphyrin/alumina was evaluated in the oxidation of (Z)-cyclooctene and cyclohexane and in the Baeyer-Villiger oxidation of cyclohexanone using iodosylbenzene or hydrogen peroxide as oxygen donors. The novel immobilized catalyst proved to be a promising system for the efficient and selective oxidation of the organic substrates with 85–92% selectivity to the epoxide in the oxidation of alkenes and 25–41% to the ketone in the oxidation of cyclohexane. As for the Baeyer-Villiger oxidation of cyclohexanone, good conversion to ԑ-caprolactone was observed as well. The material is a reusable heterogeneous catalyst, which makes it more economically feasible than its homogeneous counterpar

Differential expression and functional characterization of luteinizing hormone receptor splice variants in human luteal cells : Implications for luteolysis

The human LH receptor (LHR) plays a key role in luteal function and the establishment of pregnancy through its interaction with the gonadotropins LH and human chorionic gonadotropin. We previously identified four splice variants of the LHR in human luteinized granulosa cells (LGCs) and corpora lutea (CL). Real-time quantitative PCR revealed that expression of the full-length LHR (LHRa) and the most truncated form (LHRd) changed significantly in CL harvested at different stages of the ovarian cycle (P < 0.01, ANOVA). LHRa expression was reduced in the late luteal CL (P<0.05). Conversely, an increase in LHRd expression was observed in the late luteal CL (P<0.01). Chronic manipulation of human chorionic gonadotropin in LGC primary cultures supported the in vivo findings. LHRd encodes a protein lacking the transmembrane and carboxyl terminal domains. COS-7 cells expressing LHRd were unable to produce cAMP in response to LH stimulation. COS-7 cells coexpressing LHRd and LHRa also failed to generate cAMP in response to LH, suggesting that this truncated form has a negative effect on the signaling of LHRa. Immunofluorescence staining ofLGC and COS-7 cells implied that there is a reduction in cell surface expression ofLHRa when LHRd is present. Overall, these results imply expression of LHR splice variants is regulated in the human CL. Furthermore, during functional luteolysis a truncated variant could modulate the cell surface expression and activity of full-length LHR.Publisher PDFPeer reviewe