INHIBITION OF BOTULINUM TOXIN PRODUCTION BY PEDIOCOCCUS ACIDILACTICI IN TEMPERATURE ABUSED REFRIGERATED FOODS

The "Wisconsin process'(a combination of lactic acid starter culture and sucrose) has previously been shown to be effective in preventing botulinum toxigenesis in reduced nitrite bacon. This technology has been applied to other low-acid refrigerated foods which receive less than a 12D thermal process. A combination of Pediococcus acidilactici and dextrose was effective in preventing botulinum toxigenesis in chicken salad. When the chicken salad was temperature abused, the P. acidilactici catabolized available dextrose to lactic acid. Extracellular accumulation of the lactic acid caused a decrease in the pH of the product. Pathogen challenge tests verified that the rate and extent of lactic acid accumulation in the chicken salad during temperature abuse was sufficient to preclude botulinum toxigenesis. This technology has the potential to be of use in a variety of low-acid refrigerated foods.     

Bonding in cotton fiber from formaldehyde-free crosslinks

Cotton fabric was crosslinked with five agents, three of which were prepared form formaldehyde and two of which were formaldehyde-free. The formaldehyde-free agents produced less bonding between layers in the laminated microstructure of the cotton fiber. One agent, 4,5-dihydroxy-1,3-dimethyl-2-imidazolidinone, gave no evidence of any interlayer bonding. All five agents gave the same relationship between wrinkle recovery angle and molar substitution on the cotton up to moderate recovery angles, but only agents based on formaldehyde gave higher wrinkle recovery angles with additional reaction. Intralayer crosslinking did not reduce absorptivity, as shown by moisture regain and dye receptivity, but did restrict swelling in cupriethylenediamine hydroxide to the same extent as combined interlayer and intralayer crosslinking. The decrease in extensibility of treated fabric with increasing wrinkle recovery angle was the same with all agents. These results indicate the regions of the fiber that are important for each of these properties.     

New natural 2-acetoxy fatty acids using chemical ionization and electron impact mass spectrometry

The phospholipids of the spongePolymastia gleneni contain saturated long chain (C_22–30)-acetoxy fatty acids. Their structures were assigned based on chromatographic and spectrometric data as well as comparison with a synthetic sample. The use of capillary gas chromatography combined with chemical ionization and electron impact mass spectrometry was instrumental in the eludication of structures, since only a very small amount of crude lipids was available. Part 10 of “Phospholipids in Marine Organisms.” For Part 9 in this series, see reference 12.     

Flotation machine design: impeller—stator interaction

The separate contributions of impellers and stators to suction are studied by means of interaction models. From these, suction can be predicted when interchangeable components are used in any combination, and in either direction of impeller rotation. Methods are devised by which numerical values of the impeller and stator terms can be simply assigned. The resulting model provides good agreement with experiment. The influence of variability in component geometry is reflected in the model parameters. Possible applications of the model are suggested.     

A broad line n.m.r. study of oriented poly(vinylidene fluoride)

Broadline nuclear magnetic resonance measurements have been carried out for the proton resonance in oriented poly(vinylidene fluoride). The spectra in general show two component lines with distinctly different line widths. The broad component shows a high degree of molecular orientation and can be satisfactorily assigned to the crystalline regions of the polymer. The narrow component corresponds to an oriented non crystalline phase which is sufficiently constrained to allow motion about the chain axis only. An appreciable decrease in the value of the rigid mass fraction was observed in both of the samples over the temperature range examined. Our calculations indicate that this could play an important role in the temperature dependence of the pyroelectric response of this material.     

Laboratory accreditation in the UK

Two complementary national laboratory accreditation schemes are run by the National Physical Laboratory (NPL) to provide official recognition of competent British laboratories and an assurance of quality to their customers. The first of these, the British Calibration Service (BCS), was set up in 1966 to accredit laboratories to calibrate instruments, gauges and reference materials. In 1981 the National Testing Laboratory Accreditation Scheme (NATLAS) was formed to extend the service to all kinds of testing. Both BCS and NATLAS form an integral part of the UK national measurement system and were combined to form the National Measurement Accreditation Service on 1 October 1985.     

Combining multiple knowledge bases

Combining knowledge present in multiple knowledge base systems into a single knowledge base is discussed. A knowledge based system can be considered an extension of a deductive database in that it permits function symbols as part of the theory. Alternative knowledge bases that deal with the same subject matter are considered. The authors define the concept of combining knowledge present in a set of knowledge bases and present algorithms to maximally combine them so that the combination is consistent with respect to the integrity constraints associated with the knowledge bases. For this, the authors define the concept of maximality and prove that the algorithms presented combine the knowledge bases to generate a maximal theory. The authors also discuss the relationships between combining multiple knowledge bases and the view update problem     

Effects of seat slope and hip flexion on spinal angles in sitting

Lumbar and thoracic spinal angles of 25 male and 25 female subjects were measured in four sitting postures, with standing angles used as reference. Subjects sat with either 90 deg or 65 deg of hip flexion on either flat or forward-sloping seats. Lumbar kyphosis was greatest when the flat seat/90-deg posture was adopted and least when the sloping seat/65-deg posture was adopted. The opposite was observed for the thoracic angles, and intermediate results were observed for the other two sitting postures. No statistically significant interactions were observed among seat slope, hip flexion, and subject sex. The findings are discussed with reference to the anatomy of sitting and factors influencing pelvic tilt and the implications for the ergonomic design of chairs.