a fourth-generation ziegler-natta catalyst was prepared to synthesize polypropylene (pp), which was stabilized by in situ polymerization employing lignin as antioxidant. the antioxidant properties of lignin were compared with those of the commercial antioxidant irganox 1010. the presence of lignin in the reaction medium slightly decreased the catalytic activity of the reaction. the isotacticity...

Four of the five six-membered rings of the title penta-cylic triterpene, C(31)H(48)O(3), adopt chair conformations; the fifth, which has a C=C double bond, adopts an approximate envelope conformation.

The title compound, tetra-potassium tetra-[nickel(II)/iron(III)] penta-kis-(orthophosphate), K3.84Ni0.78Fe3.19(PO4)5, has been obtained from a flux. The structure is isotypic with that of K4MgFe3(PO4)5. The three-dimensional framework is built up from (Ni/Fe)O5 trigonal bipyramids with a mixed Fe:Ni occupancy of 0.799 (8):0.196 (10) and isolated PO4 tetra-hedra, one of which is on a general pos...

group on knowledge discovery and data mining, Boston, pp 71–80 Hand DJ, Mannila H, Smyth P (2001) Principles of data mining. MIT, Cambridge Hershberger J, Shrivastava N, Suri S (2006) Cluster hulls: a technique for summarizing spatial data streams. In: Proceedings of IEEE international conference on data engineering, Atlanta, p 138 Hulten G, Spencer L, Domingos P (2001) Mining timechanging data...

STUDY OBJECTIVES To compare the results of open myomectomy with those of laparoscopic myomectomy, and to assess complications, surgical results, total hospital cost, and morbidity associated with each procedure. DESIGN Retrospective chart review. SETTING Private practice of one surgeon, and Department of Obstetrics and Gynecology, Rush Medical College, Chicago, Illinois. PATIENTS Ninety-e...

despite the great potential of graphene as a nanofiller, achieving homogeneous dispersion remains the key challenge for effectively reinforcing polyolefin (such as polyethylene (pe) and polypropylene (pp)) nanocomposites. therefore, in this research, we report a facile combined in situ polymerization and masterbatch method for fabricating pp/reduced graphene oxide (rgo) nanocomposites. in the p...