NEGATIVE AND POSITIVE EXPLANATIONS IN EXPERT SYSTEMS

A methodology for management of constraints in VLSI data bases is presented in this paper. The process of management is based on forma! mechanisms of attribute grammar theory. Examples of a modularized knowledge representation of a circuit at interconnection and logic levels based on attribute grammars illustrate the methodology. The ultimate goal and benefit of the proposed methodology is a well-defined development technique for VLSI design tools that will allow the user to generate a transformation system, a knowledge representation, and a system to manipulate this representation, all from a simple specification. In addition, context-dependent specifications at lower levels are automatically generated from the higher-level specifications.     

SENSORY TEXTURE PROFILE, GRAIN PHYSICO-CHEMICAL CHARACTERISTICS AND INSTRUMENTAL MEASUREMENTS OF COOKED RICE

Three samples of raw-milled rice, and 4 differently parboiled rices were used to study and to relate sensory perception to instrumental measurements. Variance analysis showed that some physico-chemical characteristics indicated great differences among rice samples: thickness of cooked grain, length/width ratio, water uptake, elastic recovery, white core rate and amylose and protein contents. The most discerning sensory attributes were: elasticity, stickiness, pastiness, mealiness, length of grain, firmness, crunchiness, time in mouth, brittle texture and juiciness. The correlation circle of the principal component analysis (PCA) showed high correlation between some sensory characteristics and instrumental measurements. Melting texture, surface moistness, juiciness, were positively correlated with water uptake (r = 0.70, 0.61, 0.71). Granular texture, crunchiness, brittleness and mealiness were significantly affected by white core presence (r = 0.81, 0.74, 0.86, 0.83). Elasticity was dependent upon elastic recovery and firmness measured by the Viscoelastograph, but not linearly. Length of cooked grain was correlated with the length/width ratio of raw grain (r = 0.83). Pastiness, compactness, stickiness were slightly influenced by the thickness of raw grain (r = 0.81, 0.67, 0.72). To a weaker extent, the sensory firmness was associated with the firmness measured by extrusion force using an Ottawa cell (r = 0.58). PCA showed greatdifferences in texture between rices. Two of the parboiled rices were very elastic, another was firm, granular, crunchy and mealy. The remaining two, cooked longer, were moister and more melting. Among the 3 samples of raw-milled rices, differences in grain length feeling and melting-granular-brittle characteristics. were distinguished.     

Thermal stability of electrodeposited Ni–P alloys

Ni–P alloys were electrodeposited from phosphorous acid solutions in order to study their thermostructural stability, thermal desorption, and dimensional modifications during heat treatments. The quantity of phosphorus codeposited is not a linear function of the bath phosphorous acid content. X-ray diffraction shows that three characteristic composition ranges can be defined. In the first, corresponding to a Ni–P solid solution containing up to 9at% of phosphorus, the microstructural refining is attended by a disappearance of the (100) preferential orientation. Simultaneously with this textural change, a slight adsorption of hydrogen is observed. Beyond 9at% of phosphorus, the microcrystallized alloys are preferentially oriented in the [111] direction, and the gradual amorphization of Ni–P alloys is attended by adsorption of a very high volume of hydrogen. Beyond 17at% of phosphorus, the alloys are amorphous and the amount of hydrogen included during the electrocrystallization is at its maximum. A large part of the hydrogen is desorbed before the crystallization temperature and less of it is desorbed during the crystallization.     

Inhibition of human neutrophil elastase by wheat ceramides

Ceramides, composed of sphingosine N -acyl linked to fatty acids have become widely used in cosmetology. They play several physiological roles in the regulation of skin barrier function. Human neutrophil elastase (HNE) can be inhibited by long-chain fatty acids and their derivatives; it was therefore postulated that plant ceramides could be inhibitors of HNE. Ceramides were extracted from wheat, isolated and characterized. The main fatty acids were 16:0, 18:1, 18:2 and the sphingoid moiety was phytosphingosine. Concentrations necessary to reach 50% inhibition of HNE were, respectively, 33 and 41 μg ml^-1 for non-glycosyl ceramides (CER) and glycosyl ceramides (gly-CER) when using a synthetic specific substrate. Similar extents of inhibition were obtained using a physiological substrate, insoluble elastin. Ex vivo studies showed that CER protected human skin elastic fibres against HNE degradation. Ceramides, being natural non-toxic substances, besides their role in cosmetics, could be of pharmacological interest in dermal inflammatory disorders.     

IDENTIFYING OBJECTIVE CHARACTERISTICS THAT PREDICT CLUSTERS PRODUCED BY SENSORY ATTRIBUTES IN COOKED RICE

From eight samples of raw-milled, 10 samples of parboiled and 2 samples of canned rice, appearance, texture and flavour were determined sensorily and related to instrumental parameters and clusters of different types of rice having common sensory perceptions were identified. The physico-chemical characteristics, enthalpy of amylose-lipid complex I, protein content, length of raw grain, elastic recovery, water uptake and the viscoelastic index, varied widely between rice samples. The most discriminatory sensory attributes were appearance and texture characteristics such as 'brown', 'elastic', 'long', 'firm' and 'shiny'. The instrumental measurements were highly correlated with sensory parameters. Parboiled rice samples, characterised by a brown colour, an elastic—firm—smooth texture and a broth flavour, were different from the raw-milled rice samples described as 'juicy', 'melting', 'shiny', 'aggregated and swollen grains', 'starch and milk' flavour. Canned rice samples were distinguished by a 'jute and earth' flavour, 'bitterness' and the presence of 'foreign matter'. Five clusters of types of rice could be distinguished which were characterised by a soft texture for the first, by a sticky-pasty texture for the second, by a brioche flavour and medium intensity characteristics of sticky and melting texture for the third, by the length of grain and a slight crunchy texture for the fourth, and by the firmness and elasticity for the last cluster. Five instrumental determined characteristics, enthalpy of amylose-lipid complex I, thickness of cooked grain, water uptake, browness index and protein content classed each rice into one of these 5 clusters with an error of 4%.