INHIBITION OF BEER-SPOILAGE LACTIC ACID BACTERIA BY NISIN

149 strains of bacteria, mostly brewery contaminants able to spoil wort or beer, and 12 brewing strains of yeast (8 ale and 4 lager strains) have been screened using a well-test assay for sensitivity to the food preservative, Nisin (E234), Nisin inhibited growth of 92% of the gram-positive strains, predominantly lactic acid bacteria of the genera Lactobacillus and Pediococcus. In contrast, all 32 gram-negative strains tested, except 3 Flavobacter strains, were Nisin-resistant; in addition none of the brewing yeasts showed Nisin-sensitivity. Therefore. Nisin has potential applications in preventing spoilage of worts or beers by lactic acid bacteria.     

Dynamic range improvements and measurements in radar systems

The extension of the dynamic range performance of existing radar systems is integral to the requirement for current sensors to see deeper into clutter, that is, to detect weak signals (e.g. small targets) in the presence of strong interference (e.g. urban clutter signals). The rationale behind this requirement is that this additional capability greatly enhances the utility of military and commercial systems. Two approaches to improving the dynamic range of modern radar and surveillance receivers are described: (1) linearisation of intermodulation distortion (IMD) using digital post-distortion algorithms and (2) linearisation of IMD using frequency retranslation mixer (FRM). The experimental results presented illustrate that the digital post-distortion and FRM approaches are effective in providing IMD improvements for the hardware and test scenarios measured. The improvements measured ranged from 15 to 35 dB for narrowband signals to 2-6 dB for frequency-modulated continuous wave (FMCW) wideband signals. The digital post-distortion approach provided the greatest performance improvement when the input signals were between the analogue-to-digital converter full range and 20 dB below that level. The improvements measured for the FRM linearisation approach ranged from 20 to 25 dB for the narrowband two-tone tests and 16-18 dB for the wideband FMCW signal chirps.     

GENE TECHNOLOGY FOR INDUSTRIAL YEASTS

Yeast genetics is now available as a practical tool for the development of brewing industry practices. The contribution of Brewing Research Foundation work (1978–84) to recent advances is illustrated by the construction of brewing strains with superattenuating (amylolytic) or anti-contaminant properties. Approaches based on hybridisation (by rare mating) or recombinant DNA technology have been evaluated. Techniques developed for (i) gene transfer to brewing strains, (ii) ensuring stable inheritance of novel characteristics and (iii) exploiting the secretory ability of yeast strains, can be widely applied not only with brewing, distilling, baking or wine yeasts, but also in the use of yeasts to produce novel biotechnical products. ‘Spin-off’ from these studies includes valuable methods for differentiating or enumerating wild yeasts in brewery quality control.     

On the "general acceptance" of eyewitness testimony research: A new survey of the experts.

In light of recent advances, this study updated a prior survey of eyewitness experts (S. M. Kassin, P. C. Ellsworth, & V. L. Smith, 1989). Sixty-four psychologists were asked about their courtroom experiences and opinions on 30 eyewitness phenomena. By an agreement rate of at least 80%, there was a strong consensus that the following phenomena are sufficiently reliable to present in court: the wording of questions, lineup instructions, confidence malleability, mug-shot-induced bias, postevent information, child witness suggestibility, attitudes and expectations, hypnotic suggestibility, alcoholic intoxication, the cross-race bias, weapon focus, the accuracy–confidence correlation, the forgetting curve, exposure time, presentation format, and unconscious transference. Results also indicate that these experts set high standards before agreeing to testify. Despite limitations, these results should help to shape expert testimony so that it more accurately represents opinions in the scientific community. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Polymerization of drying oils. VI. Catalytic polymerization of fatty acids and esters with boron trifluoride and hydrogen fluoride

Summary At relatively low temperatures boron trifluoride and hydrogen fluoride gave high yields of polymers from soybean fatty acids and methyl esters. The use of 2% boron trifluoride as catalyst at 150° to 200° resulted in the polymerization of 50–60% of the methyl esters within one hour. The viscous polymeric fraction usually had a dark color, a high acid number, and a low ratio of dimer to higher polymer. The boron trifluoride-ether complexes were equally effective catalysts and more convenient to handle. Use of the aliphatic ether complexes resulted in products having lighter colors. It was necessary to use large amounts of hydrogen fluoride to produce comparable yields at less than 100°, but 70% yields of polymers having light colors and low acid numbers were obtained. Presented at fall meeting of American Oil Chemists' Society in Chicago, Oct. 8–10, 1951. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture. Report of a study made under the Research and Marketing Act of 1946.     

2μm DNA PLASMID IN BREWERY YEASTS

Using an agarose gel screening procedure, 2 μm DNA plasmid was detected in all of 10 brewing strains of Saccharomyces yeast examined and in both of two non-brewing, dextrin-utilising strains. Plasmid DNA was identified in yeast grown with access to air in MYGP medium or in hopped wort, and in yeast harvested from 3-day wort fermentations. The yeast plasmid is a suitable self-cloning vector for the genetic manipulation of brewing yeasts by transformation.     

Characterisation and quantification of the sources of PM10 during air pollution episodes in the UK

Data for concentrations of PM(10) and gaseous pollutants from sites in the UK Automatic Urban and Rural Network have been examined during periods of elevated concentrations of PM(10). The ratios of concentrations of PM(10) to those of the other pollutants were used to determine the most probable source of the additional particles. The hypothesis is that because the concentrations of PM(10) were divided by those of the other pollutants, the ratio should decrease when PM(10) and the other pollutants have a common source. Conversely, the ratio should increase when the sources are different. During episodes where road traffic was the most probable source of the additional particles, the ratios of concentrations of PM(10) to carbon monoxide and oxides of nitrogen did decrease, but the comparable ratios for sulphur dioxide and ozone increased. In contrast, during episodes known to have been caused by construction activity, all these ratios increased. This is taken to show that the basic hypothesis is valid. For prolonged episodes, it was possible to use data averaged over the total duration of the episode for the purposes of source identification. For sporadic construction, or other short-duration episodes, it was necessary to use time series data. The data have also been used to calculate the differences between hourly average concentrations of pollutants measured during episodes and long-term hourly average concentrations. These have been used to model the additional PM(10) during air pollution episodes associated with construction activities and road traffic emissions. This confirms the lack of relationship between PM(10) and other pollutants during construction works. During episodes arising from road traffic emissions, there was good agreement between measured and modelled additional concentrations of PM(10) when an appropriate factor, F, related to the contribution of road traffic emissions to PM(10) at different site types was applied. The values used were 0.2 (Suburban), 0.3 (Urban Background/Urban Centre), and 0.5 (Roadside), representing 20%, 30%, and 50% contributions from road traffic, respectively.     

REGULATION OF AMYLOGLUCOSIDASE PRODUCTION BY SACCHAROMYCES DIASTATICUS

In wort fermentations, production of extracellular amyloglucosidase (AMG) by Saccharomyces diastaticus was greatest, and initiated earliest, when the requirement of yeast for oxygen or unsaturated lipid was incompletely satisfied. During such fermentations, maltotriose disappeared before maltose, glucose, the product of AMG action, accumulated and the wort was inadequately attenuated. In all circumstances examined, commencement of dextrin breakdown coincided with initiation of AMG excretion. Prior to excretion, active enzyme was associated with yeast cells but was located externally to the plasma-membrane. Dextrin or starch was not required to induce AMG production which is initiated, we conclude, when the carbon and energy-source becomes growth-limiting. S. diastaticus strains hydrolysed only a small proportion of wort dextrine and AMG produced in beer was unable to release glucose from pullulan. For production of low carbohydrate beer, strains which (i) synthesise significant amounts of a ‘debranching’ enzyme and (ii) are catabolite-derepressed for AMG production would be advantageous.     

"Eyewitness researchers as experts in court: responsive to change in a dynamic and rational process": Comment.

Responds to the comments by M. L. McCullough (see record 2002-12932-018) on the original article (see record 2001-17140-001) which discussed eyewitness testimony. The current author states that McCullough's commentary rests on a foundation of assumptions that were both na?ve and erroneous. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

THE STRUCTURAL AND STORAGE CARBOHYDRATES OF SACCHAROMYCES CEREVISIAE: CHANGES DURING FERMENTATION OF WORT AND A ROLE FOR GLYCOGEN CATABOLISM IN LIPID BIOSYNTHESIS

Detailed analysis of the structural and storage carbohydrates of Saccharomyces cerevisiae (NCYC 240) during wort fermentation showed that there were no significant changes in the amounts of trehalose or alkali-soluble glycogen. However, glucan and mannan individually increased from ca4% of the yeast dry weight at pitching to ca6% during the first 3–17 h of fermentation, butthen declined to the former level. In the first 2 h of fermentation, prior to yeast multiplication, acid-soluble glycogen was rapidly dissimilated from ca 40% to ca 6% of the yeast dry weight. During this period of oxygen uptake, wort sugars were not removed by the yeast. Glycogen, therefore, was the sole source of metabolic energy for lipid resynthesis and hexose transport appeared to require the formation of a component membrane. During the latter phase of fermentation when the yeast was not growing but expending energy for maintenance of cellular functions, glycogen reserves were slowly depleted; after a period of prolonged anaerobic storage, the content of glycogen fell well below that which was initially present in the pitching yeast.