Fats and oils as feedstocks for oleochemicals

The approximate quantity of 3 million tons estimated to be required at present for the production of oleochemicals is to be covered from a total production of more than 60 million tons of vegetable and animal fats. While the quantity of eleochemicals produced has nearly doubled in recent years, vegetable oil production alone has increased from 25 to 40 million tons in the same period. More than half the feedstocks required for oleochemicals are acid oils and other fats and oils which are unsuitable for human food. The demand for fats and oils for oleochemicals will certainly grow for price and technological reasons, but only the use of large quantities of oils and fats for diesel engines could shift this balance drastically and endanger the world supply of edible fats. A bottleneck may arise in the supply of fatty acids of medium chain length, although the use of coconut and palm kernel oil by the food industry in the highly developed countries has been on the decline. The green revolution goes on and the fat supply grows faster than the population. In addition, new approaches to plant breeding and agriculture, and biochemical processes as well, might help circumvent any conceivable shortage in the supply of oils and fats in general, and in the supply of special fatty acids in particular.     

100 Jahre Margarine — vom Ersatzprodukt zum Grundnahrungsmittel

100 Years of Margarine — From a Substitute to a Basic Food-Stuff Inspite of the outdated and discriminating regulations that were obstructive, margarine, since the patent application in 1869 by Mège-Mouriés, has turned out to be an important foodstuff. In countries with high standard of living and progressive thinking in nutritional matters like USA, Sweden and Holland as well as in the Federal Republic of Germany the consumption of margarine as spread and cooking fat is higher than butter. Margarine as an independent food-stuff has the advantage that its composition and structure can be varied to meet the demands of the housewife, thereby taking the nutritional aspects into consideration as well. Owing to the modern technology and packaging involved in its production margarine is an extremely hygienic food-stuff with fully acceptable taste. In view of expanding population and high acrage yield of vegetable oils, margarine has a great future as a cheap and economically purposeful food-stuff.     

Multigrid interpretations of the parareal algorithm leading to an overlapping variant and MGRIT

Computing and Visualization in Science - The parareal algorithm is by construction a two level method, and there are several ways to interpret the parareal algorithm to obtain multilevel versions....     

Physico-chemical and antigenic properties of tetanus and diphtheria toxoids and steps towards improved stability

Physico-chemical, antigenic and immunogenic properties may be altered during microencapsulation of antigens and their release from poly(lactic acid) and poly(lactic-co-glycolic acid) microspheres. Here, the physico-chemical, conformational and antigenic stability of tetanus and diphtheria toxoids was studied in aqueous solutions stressed by elevated temperature and the presence of lactic and glycolic acids. Further, the stabilising effect of albumin was investigated. The analytical tools used were fluorimetry, circular dichroism spectroscopy, turbidimetry, electrophoresis and ELISA. Elevated temperatures altered the physico-chemical and antigenic properties of the toxoids to a greater extent than the acids (50 mM) did. Substantial unfolding and chemical changes of tryptophan were observed upon 1-4 weeks of incubation at 60 degreesC. At 4 degreesC, only minor conformational changes were observed, even in the presence of the acids. Furthermore, 40% of the tetanus toxoid antigenicity was lost after 7 days at 37 degreesC. This loss increased in the presence of the acids. At 60 degreesC, the antigenicity had completely vanished. Very importantly, 0.5% albumin preserved the tetanus antigenicity over 6 weeks' incubation at 37 degreesC, regardless of the presence of glycolic acid. This qualifies albumin as potential stabilising additive for toxoid loaded poly(lactic acid) and poly(lactic-co-glycolic acid) microspheres.     

Sprint start instrumentation

A prototype instrument has been developed to measure the forces generated on the starting blocks and the speed of a sprinter at the start of a sprint event. The starting block forces can be resolved into horizontal and vertical components for each foot, or the various combinations of these four forces can be calculated and displayed along with the resultant angle. The speed of the sprinter is measured by means of a Doppler microwave technique (radar gun). Both static and dynamic tests have been used to calibrate the force transducers and to verify their functional bandwidth. The speed measurement technique has been validated by four independent procedures: measurement of a constant velocity object; measurement of an object undergoing constant acceleration; determination of distance travelled by an athlete; and comparison with high-speed cinematography. Both the force and speed profiles can be displayed immediately on the screen of a microcomputer for feedback to the coach and athlete during training sessions     

Determination of nerve conduction velocity distribution fromsampled compound action potential signals

The sampled compound action potential (CAP) data sequence was expressed as the circular convolution of the delay sequence and the sampled single fiber action potential (SFAP) data sequence. An algorithm, based on Hirose's method (1986) was then developed to separate the delay sequence from the sampled CAP data sequence, and the nerve conduction velocity distribution (NCVD) was consequently calculated from the delay sequence. The NCVD was found to be the product of the amplitude of the SFAP and the number of fibers. Simulations show that the estimated results were in good agreement with the calculated results. Experiments were performed on ten sciatic nerves from five bullfrogs (Rana pipens) using two independent variables: interelectrode distance and stimulus current strength. The results estimated from CAP's recorded under each condition reflect the corresponding feature of NCVD of the condition. The advantage of the technique is to provide detailed information about both slow and fast conducting fibers. This technique also offers the possibility to directly calculate the nerve fiber diameter distribution from the sampled CAP data sequences     

Crosslinked Poloxamers as a Versatile Monolithic Drug Delivery System

There is growing interest in the development of homogeneous monolithic drug release systems for various routes of administration. One very attractive type of such dosage forms is based on hydrophilic water-swellable polymers which generally exhibit high biocompatibility. On contact with an aqueous liquid (dissolution medium or gastrointestinal fluid) the polymer swells. Liquid penetrates into the system and drug is released by counter-current diffusion. Depending on the physical characteristics of the polymer, different thermodynamic transitions such as glass-to-rubber transition of the amorphous zones or melting out of crystallites may occur during liquid penetration. These thermodynamic reactions might be responsible for the drug release kinetics not showing square-root-of-time dependance^1-5.