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Biomedical subjects

G Knowles

Publications and source records attributed to G Knowles.

45 records · Page 3Linked to original sources
PubMed1980

Variable expression of virulence in the rodent malaria parasite Plasmodium yoelii yoelii.

The expression of the virulence character in the virulent line (YM) of Plasmodium yoelii yoelii was investigated. The level of virulence was measured by counting the parasitaemia of the mature red blood cells. Several sub-clones were isolated from the virulent line YM and each was tested for its level of virulence. Out of 10 sub-clones 1 showed a marked decrease in virulence. However, transmission of this sub-clone through mosquitoes fully restored its virulence. A clone isolated from the progeny of a cross between mild and virulent parents had an intermediate level of virulence. A sub-clone isolated from this intermediate virulent line exhibited greatly reduced virulence. Mosquito transmission of this sub-clone also restored its virulence to a level comparable with the virulent line YM.

Animals↗
PubMed1976

The action of the excretory apparatus of Calliphora vomitoria in handling injected sugar solution.

Recent evidence suggests that the isolated Malpighian tubules of Calliphora possess mechanisms which restrict the loss of glucose and trehalose from the insect. This report establishes that the intact, diuresing fly does not excrete glucose or trehalose when solutions of these sugars are injected. When solutions of non-metabolized sugars such as sorbose and xylose are injected into the fly, these sugars are rapidly excreted. High concentrations of sorbose and xylose are found in the urine, suggesting that rapid reabsorption of fluid occurs in the excretory apparatus even during the diuresis which the injections provoke. However, injected sucrose is apparently not excreted in large amounts and it is possible that the Malpighian tubules when functioning in vivo are impermeable to disaccharides.

Amaranth Dye↗
PubMed1975

The removal of sulphate by the excretory apparatus of the blowfly Calliphora vomitoria.

The excretion of sulphate by the isolated Malpighian tubules of Calliphora vomitoria has been investigated. Contrary to expectation, it was found that the isolated tubules are freely permeable to sulphate. The rate of sulphate secretion is comparable to the rates of secretion of both phosphate and chloride. The excretion of sulphate by the intact fly has also been verified.

Animals↗
PubMedDate not supplied

Linear B-cell epitopes in the N-terminus of L2 of bovine papillomavirus type 4.

The minor capsid protein L2 of bovine papillomavirus type 4 (BPV-4) is a very effective prophylactic vaccine which induces the production of virus neutralising antibodies and prevents virus-induced papillomatosis. The virus neutralising activity resides in the first 200 N-terminal amino acids of L2 (L2a). To further investigate the humoral immune response to L2, and the role it plays during infection and in prophylactic vaccination, the presentation of B-cell linear epitopes of L2a has been analysed in calves infected with the virus but not vaccinated, and in calves vaccinated with virus, L2a or E7. Several B-cell epitopes have been identified in L2a by the use of overlapping peptides; the epitopes varied in the different groups of animals, indicating that the epitopes presented by denatured L2 are not presented by the virus, and that therefore, although responsible for L2 vaccine-induced immunity, they may play little role in naturally acquired immunity.

Animals↗
PubMedDate not supplied

A practical methodology for analysing and improving the measurement system.

Measurement systems are used widely in manufacturing organisations in order to make many important decisions. These decisions range from the acceptability of a given product against tolerance requirements to the level of statistical control of a process or its capability to consistently perform a given task. In most situations, however, little thought is given to the quality of the data generated by such measurement processes. By using potentially flawed data in making fundamental manufacturing decisions, organisations undermine the quality of the decision-making process itself. This paper reviews the approaches presently available from both a technical and a practical point of view, based on the priorities of process improvement practitioners. The conclusion of the paper is that the Evaluation of the Measurement Process proposed by Wheeler and Lyday offers the best balance of accuracy and utility.

Analysis of Variance↗
PubMedDate not supplied

Gauge Capability Analysis: classical versus ANOVA.

In order to use Statistical Process Control (SPC) efficiently and effectively in today's modern industrial environment, it is essential to analyze and determine the extent of gauge variability. The variation that occurs on a control chart is essentially a combination of product and gauge variation. Studies of measurement or gauge variation are absolutely a waste of resources unless they can lead to a substantial reduction in process variability or to an improvement in process and product quality. The goal of gauge capability analysis is an understanding and quantification of the various sources of variability present in the measurement process. The purpose of this paper is to illustrate the fundamental difference between Classical Gauge Capability Analysis (CGCA) and the use of a more powerful approach based on the Analysis of Variance (ANOVA). The author recommends that the latter approach is more useful and powerful in the presence of an interaction between the parts and the operators involved in the measurement process. An example is illustrated in the paper to demonstrate the two approaches.

Analysis of Variance↗