Resolution of the Stick-slip Friction Traces of Fabrics

Some new frictional parameters of fabrics determined by the trace analysis of their stick-slip friction property is reported. Both scouring and mercerization processes induce structural consolidation which in turn can increase the frictional resistance, number, amplitudes of the stick-slip, and the differential frictional forces of the fabrics. This result is ascribed to an increase in the crimp propensity of yarns. The magnitudes of the frictional parameters of weft pile fabrics are correlated with the numerical estimates of the tactile stimuli of their surface roughness. A good linear relation exists between the values of objective and subjective roughness of fabrics on a logarithmic scale.     

From cassava to gari: mapping of quality characteristics and end-user preferences in Cameroon and Nigeria

User’s preferences of cassava and cassava products along the value chain are supported by specific root quality characteristics that can be linked to root traits. Therefore, providing an evidence base of user preferred characteristics along the value chain can help in the functional choice of cassava varieties. In this respect, the present paper presents the results from focus group discussions and individual interviews on user preferred quality characteristics of raw cassava roots and the derived product, gari, – one of the major cassava products in Sub-Saharan Africa – in major production and consumption areas of Cameroon and Nigeria. Choice of cassava varieties for farming is mainly determined by the multiple end uses of the roots, their agricultural yield and the processing determinants of roots that support their major high-quality characteristics: size, density, low water content, maturity, colour and safety. Processing of cassava roots into gari goes through different technological variants leading to a gari whose high-quality characteristics are dryness, colour, shiny/attractive appearance, uniform granules and taste. Eba, the major consumption form of gari in Cameroon and Nigeria, is mainly characterised by its textural properties: smoothness, firmness, stickiness, elasticity and mouldability. Recommendations are made, suggesting that breeding will have to start evaluating cassava clones for brightness/shininess, as well as textural properties such as mouldability and elasticity of cassava food products, for the purpose of supporting decision-making by breeders and the development of high-throughput selection methods of cassava varieties. Women are identified as important beneficiaries of such initiatives giving their disadvantaged position and their prominent role in cassava processing and marketing of gari.     

Effect of mechanical deboning process on the fat stability of 3 tropical fish species stored at -10 degrees C

Maximum advantage of certain fish species captured with shrimp, at present not fully utilized, constitutes a necessity in Venezuela. The purpose of this research work was to evaluate the stability of three of those fish species: bagre, cunaro and caballa, based on the changes that might occur in their fat content. This was done by comparing both the edible part of the whole fish, as well as the deboned flesh of each of them. Evaluation of the changes was performed by means of the acid and peroxide indices, with previous fat extraction, and the thiobarbituric acid (TBA) index. On the other hand, the fatty acids profile of the three species studied was determined by gas chromatography. According to our findings, the greater alteration was detected in the deboned sample, obtaining the highest TBA and acidity index values of all species, on the third month of storage; then a reduction of these values was observed. On the other hand, the peroxide index presented heterogeneous values in the three species analyzed through their storage period. The predominant fatty acids were: palmitic (16:0) among the saturated, and oleic (18:1) among the unsaturated. A greater proportion of unsaturated fatty acids was found in the three species. An increment of these in the deboned sample with respect to the whole fish, was also observed.     

Improving cooking efficiencies: Barbecuing reassessed

Barbecuing is becoming increasingly popylar, yet is notoriously energy-inefficient. So the factors affecting the thermal efficiency of this process, as well as the quality of the food so cooked, especially in Nigeria, have been investigated. Design recommendations are presented.     

General equation for quasisinusoidal oscillators

A nonlinear differential equation has been obtained to describe the behaviour of any quasisinusoidal oscillator, Simple relationships are also proposed whereby the frequency and amplitude of an oscillation can be calculated and its stability verified. Application examples involving some typical circuits are then given.     

Prostate-specific antigen, a serine protease, facilitates human prostate cancer cell invasion

Human prostatic epithelial cells constitutively secrete prostate-specific antigen (PSA), a kallikrein-like serine protease, which is a normal component of the seminal plasma. PSA is currently used as a specific diagnostic marker for the early detection of prostate cancer. We demonstrate that PSA degrades extracellular matrix glycoproteins fibronectin and laminin and, thus, may facilitate invasion by prostate cancer cells. Blocking PSA proteolytic activity with PSA-specific mAb results in a dose-dependent decrease in vitro in the invasion of the reconstituted basement membrane Matrigel by LNCaP human prostate carcinoma cells which secrete high levels of PSA. A novel PSA-SDS-PAGE zymography method for the detection of matrix degrading ability of PSA is also described. We propose that: (a) because of the dysplastic cellular disorganization in early neoplastic lesions called prostatic intraepithelial neoplasia (PIN), PSA may be secreted not only at the luminal end but also, abnormally, at the cell-basement membrane interface, causing matrix degradation and facilitating invasion; and (b) PSA, along with urokinase, another serine protease secreted by prostatic epithelium, may be involved in the proteolytic cascade during prostate cancer invasion and metastasis. The discovery of the extracellular matrix degrading ability of PSA not only makes it a marker for early detection but also a target for prevention and intervention in prostate cancer.