Vanadium-modified (SiO2/MgO/MgCl2)•TiClx Ziegler-Natta catalysts were prepared through co-impregnation of water-soluble magnesium and vanadium salts under different pH values. Several key factors such as pH value of co-impregnation solution during catalyst preparation, catalyst performances including catalytic activity, ethylene/1-hexene copolymerization and hydrogen response were investigated....

Synthesis of magnesium nickel oxide phase such as MgxNi1-xO solid solutions has been studied in this research article using mechnochmical reaction between magnesium and nickel oxide. Mixtures of magnesium powder and nickel oxide (Mg+NiO) with stoichiometric compositions were milled for different times in a planetary ball mill. Reduction reaction of nickel oxide by magnesium via a mechanically i...

Selected results for the synthesis of cyclic olefin copolymers (COCs)—especially copolymerizations of norbornene (NBE) or tetracyclododecene (TCD) with ethylene and α-olefins (1-hexene, 1-octene, 1-dodecene)—using group 4 transition metal (titanium and zirconium) complex catalysts have been reviewed. Half-titanocenes containing an anionic ancillary donor ligand, Cp’TiX2(Y) (Cp’ = cyclopentadien...

PURPOSE To verify if titanium spiral tacks may contribute to intra-abdominal adhesion formation in rabbits. METHODS Ten New Zealand white rabbits were used. Through videolaparoscopic surgery two titanium spiral tacks (ProTack(®), Covidien(®)) were applied in the right flank. After 30 days the animals were submitted to evaluate peritoneal cavity by videolaparoscopy. RESULTS No adhesion was f...

Structurally well-defined bimetallic titanium(IV) (salen) and monometallic vanadium(V) (salen) complexes have been used as catalysts for the asymmetric addition of trimethylsilyl cyanide to β-nitroalkenes to produce chiral nitronitriles with ee values in the range of 79-89 % and conversions up to 100 % at 0 °C. The reaction conditions (solvent, temperature, time and vanadium complex counter-ion...

PURPOSE To determine the nature and the origin of metallic foreign particles appearing on the iris after phacoemulsification surgery. SETTING P.D. Hinduja Hospital and Medical Research Centre, Mumbai, Maharashtra, India. DESIGN Case series. METHODS Metallic foreign particles were observed on the iris surface and the pupillary border on the first postoperative visit after phacoemulsificati...

Introduction: The magnesium alloy was fabricated into orthopedic plates, and used to repair tibial fractures of New Zealand white rabbits. osteogenesis degradation behavior plates were investigated in vivo. Methods: 38 rabbits randomly divided an experimental group using the plate control a titanium plate. Tibial fixed with respectively. An X-ray fracture site taken at 1, 2, 4, 8, 16 weeks afte...

Background: Implant-associated infections are a result of bacterial adhesion to an implant surface and subsequent biofilm formation at the implantation site. This study compares different magnesium materials based on their ability to resist bacterial adhesion as well as further biofilm formation. Material and Methods: The surfaces of four magnesium-based materials (Mg2Ag, Mg10Gd, WE43 and 99.99...

In Ziegler-Natta olefin polymerization, the pore architecture of catalysts plays a crucial role in catalytic performances and polymer properties. While the type of preparation routes (such as chemical reaction and solution precipitation) greatly affects the catalyst pore architecture as a result of different solidification mechanisms, the modification of the pore architecture within a given rou...