RHEOLOGY AND MICROSTRUCTURE OF WHEAT DOUGH DEVELOPED WITH CONTROLLED DEFORMATION

Undeveloped wheat dough samples were strained in shear and extensional flow between parallel plates to produce a controlled level of development. Dough made in a standard Farinograph, considered developed dough, was used for comparison. Scanning electron microscopy images of deformed dough were subjected to numerical image processing to characterize the protein matrix present. Results were compared to dynamic rheological properties to evaluate the influence of strain deformation on the formation of microstructure. Viscoelastic moduli of wheat dough showed that developed dough had the greatest amount of structure formation, followed by extensionally-strained and shear-strained samples, respectively. Undeveloped dough showed the lowest levels of structure development. Image analysis indicated statistically significant differences between protein matrices in developed and undeveloped samples; however, results were not significantly different between shear- and extension-ally-strained samples.     

Hypothalamic neurons and defensive reflexes

Identified groups of neurons in positive (the lateral hypothalamic area, the lateral preoptic area) and negative (the ventromedial hypothalamus) emotional regions were examined under the different levels of food motivation and emotionally positive and negative intracranial stimulation. The responses of the neurons in classical and operant conditioning were different. This difference was manifested in tonic (during location of the animal into the chamber) and phasic alterations of neuronal activity and at certain stages of conditioned reflex performance. During classical conditioning were revealed the reciprocal relations in unit activity of the positive and negative emotional structures. During the operant reflex more complicated pattern of reactions was observed being connected with realization of a necessity of removing from the negative influences. During defensive reflex in the cases of classical conditioning and avoidance reaction reinforcement was related with engaging the negative emotional mechanisms while in the course of escape reaction the positive emotional mechanism being engaged.     

Analytical techniques for cell fractions. XXIII. A stable thermal gradient device for heat denaturation studies on proteins

The ISO-DALT two-dimensional electrophoretic system (1,2), based on the method of O'Farrell (3), is capable of performing large numbers of analysis on complex mixtures of proteins. However, both separations employed are carried out under dissociating or denaturing conditions and no enzyme activities are readily observable in the analyzed proteins. In order to identify the spots corresponding to particular enzymes, it is therefore necessary to employ some nondestructive resolving technique first and as a second step to perform both enzyme and two-dimensional electrophoretic analyses on the fractions generated. By correlating enzyme activity with intensity of various spots on the two-dimensional gels throughout the series of initial fractions, identifications, can be made. This approach, unlike the more direct immunoprecipitation methods (4), requires the running of large numbers of enzyme analyses and two-dimensional gels and some convenient initial resolving procedure. Convenient and rapid techniques for the analyses (5,6) and gels (1,2) have been described previously in this series and elsewhere. This paper deals with the use of selective denaturation in a temperature gradient as an initial resolving procedure and describes a simple thermal gradient device for generating such a gradient.