ABSTRACT
Itaconic acid (IA) is an unsaturated dicarbonic organic acid. It can easily be incorporated into polymers and may serve as a substitute for petrochemical-based acrylic or methacrylic acid. It is used at 1-5% as a co-monomer in resins and also in the manufacture of synthetic fibres, in coatings, adhesives, thickeners and binders. The favoured production process is fermentation of carbohydrates by fungi, with a current market volume of about 15,000 t/a. Due to the high price of about US$ 4/kg, the use of IA is restricted. At present, the production rates do not exceed 1 g l(-1) h(-1), accompanied by product concentrations of about 80 g l(-1). New biotechnology approaches, such as immobilisation techniques, screening programmes and genetic engineering, could lead to higher productivity. Also, the use of alternative substrates may reduce costs and thus open the market for new and increased applications.
Subject(s)
Biotechnology/methods , Succinates/metabolism , Aspergillus/genetics , Aspergillus/growth & development , Aspergillus/metabolism , Biotechnology/economics , Biotechnology/history , History, 19th Century , History, 20th Century , Succinates/historyABSTRACT
Canine cancellous bone is used as a model for human bone in experimental orthopedic research, including models of total knee arthroplasty. Depth-force measurements produced by small-diameter indentation testing were used to derive the variation of Young's modulus over the transverse cross-sectional surface at three levels within the proximal canine tibia. At the most proximal section the presence of lateral and medial peaks of equal modulus (approximately 1100 MPa) was found. Modulus averages for the three resection levels revealed a trend of distally decreasing values, from 692 MPa proximally to 417 MPa distally. Average regional modulus values for the canine tibia were 50-75% higher than previously reported for the tibia of healthy young adult humans, although the local maxima were only 5-20% greater in canines.
Subject(s)
Tibia/physiology , Adult , Animals , Bone and Bones/physiology , Disease Models, Animal , Dogs , Elasticity , Hardness , Humans , Knee Prosthesis , Male , Regression Analysis , Stress, MechanicalABSTRACT
Interpretation of clinical laboratory results, aside from clinical considerations, is based on the probability of the result being within a given normal range. This probability is influenced by the degree of error inherent in the analytical method. It would be advantageous to assign a more definite probability to the result of the measurement by combining the error distribution of the result around the true value and the distribution of the healthy population that serves as a reference. Bayesian statistics permits the revision of this prior information into a single probability.
