Patellofemoral crepitus in high flexion rotating platform knee arthroplasty.

Introduction: Recently, implant manufacturers have made modifications to currently available implants in an attempt to improve postoperative flexion. The Low Contact Stress (LCS) RPS (DePuy Orthopaedics Inc., Warsaw, IN, USA) is one such prosthesis which is a modification of the established LCS RP design.

Quantification of denitrification potential in carbonaceous trickling filters.

Biofilm samples from a carbonaceous trickling filter (TF) were evaluated in bench scale reactors to determine their maximum potential denitrification rates. Intact, undisturbed biofilms were placed into 0.6 L bench-scale reactors filled with sterilized, primary clarifier effluent spiked with nitrate to a final concentration of 16-18 mg/L as N.

Effect of alkalinity type and concentration on nitrifying biofilm activity.

The effect of alkalinity on nitrifying biofilm activity was determined by collecting 21-day-old biofilm samples from the top of a full-scale nitrifying trickling filter and evaluating bench-scale nitrate plus nitrite generation rates at (1) various initial carbonate alkalinity concentrations and (2) with four types of available alkalinity: carbonate only, phosphate only, phosphate plus hydroxide, and phosphate plus carbonate. Initial carbonate alkalinity concentrations were varied between 308 and 20 mg/L as calcium carbonate (CaCO3). Ammonia, nitrite, and nitrate concentrations were measured at time zero, 90 minutes, 180 minutes, and 270 minutes.