Stoichiometric dye-binding procedure for the determination of the reactive lysine content of soya bean protein

A new analytical method has been developed for the determination of the reactive lysine content of soya bean protein. The method is based on the reaction of the free basic groups of the protein with 1-phenylazo-2 naphthol-6,8 disulphonic acid. With regard to the stoichiometry of the procedure, it has been proved, contrary to earlier reports, that the basic amino acids, histidine, arginine and lysine, each combine with one mole of the dye. After acylation with propionic anhydride lysine alone loses its dye reactivity. The usefulness of the proposed method has been demonstrated by the determination of the reactive lysine content of several untreated, heat-treated and acid-treated soya bean samples. The results show that heat damage of about 5% in reactive lysine content can be measured in 1·5 h with good reproducibility.     

The multicultural perspective in therapy: A social constructionist approach.

Discusses the theoretical and clinical applications of the postmodern paradigm of social constructionism as a basis for counseling culturally different clients. Such applications avoid the trap of perpetuating the status-quo when working with minority and marginalized clientele. The main points of multiculturalism and social constructionism are summarized, and issues of mutual concern to both perspectives are examined. Applications to psychotherapy are explored, and the challenges of applying the social constructionist approach to culturally competent counseling are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of an octocalcium phosphate cement

From previous studies it is known that alpha-tertiary calcium phosphate and dicalcium phosphate form a cement upon mixing with water. In this study this cement was optimized in terms of the milling of the constituents, their molar ratio, the amount of hydroxyapatite added and the water/powder ratio. The optimum Ca/P molar ratio of the cement mixture was 1.36±0.03. X-ray diffraction showed the reaction product to be octocalcium phosphate. Addition of precipitated hydroxypatite of over 3% diminished the final strength of the cement significantly. However, admixtures of only 2% of precipitated hydroxyapatite (a) kept the final compressive strength at 30±5 MPa after soaking in Ringers solution at 37°C, (b) diminished the initial setting time from 27.5 to 10 min and the final setting time from 65 to 40 min, (c) diminished the time in which the final strength was reached from 36 to less than 14 h. The tensile strength of this cement is 19±1% of its compressive strength. The optimum water/powder ratio as found in this study was 0.30 g/g.     

Using artificial intelligence to model heavy plate mill rolling

This research summary discusses the application of neural networks, evolutionary strategies, and other artificial intelligence techniques in the modeling and optimization of the models used for temperature, rolling force, and torque calculation in heavy plate milling.     

Influence of DNA repair by ada and ogt alkyltransferases on the mutational specificity of alkylating agents

We investigated the influence of the alkyltransferases (ATases) encoded by the ada and ogt genes of Escherichia coli on the mutational specificity of alkylating agents. A new mutational assay for selection of supF- mutations in shuttle-vector plasmids was used. Treating plasmid-bearing bacteria with N-methyl-N-nitrosourea (MNU), N-ethyl-N-nitrosourea (ENU), and ethyl methanesulfonate (EMS) dramatically increased the mutation frequency (from 33-fold to 789-fold). The vast majority of mutations (89-100%) were G:C-->A:T transitions. This type of mutation increased in ada- (MNU) or ogt- (ENU) bacteria, suggesting that repair of O6-methylguanine by ada ATase and repair of O6-ethylguanine by ogt ATase contribute mainly to the decrease in G:C-->A:T transitions. The analysis of neighboring base sequences revealed an overabundance of G:C-->A:T transitions at 5'-GG sequences. The 5'-PuG bias increased in ATase-defective cells, suggesting that these sequences were not refractory to repair. G:C-->A:T transitions occurred preferentially in the untranscribed strand after in vivo exposure. That this strand specificity was detected even in bacteria devoid of ATase activity (ada- ogt-) and not after in vitro mutagenesis suggests a bias for damage induction rather than for DNA repair. Highly significant differences were found between the in vivo and in vitro incidences of G:C-->A:T substitutions at the two major hotspots, positions 123 (5'-GGG-3'; antisense strand) and 168 (5'-GGA-3'; sense strand). These results are explained by differences in the probability of formation of stem-loop structures in vivo and in vitro.