Effect of aqueous ammonia and other alkalis on the in-vitro digestibility of barley straw

The in-vitro digestibility of the organic matter of unground barley straw was increased by approximately 14 units by treatment with aqueous ammonia for 1 week at 20°C. Longer treatment times of 4 and 13 weeks had little or no additional effect on digestibility. Treatment with sodium hydroxide or tetramethylammonium hydroxide increased digestibility by up to 22 units. The content of cell walls of the straw after treatment with any of the alkalis was lower than that of untreated straw and the degradability of the walls from alkali-treated straw was more than 85% greater than that of the walls from untreated straw. Alkali treatment of straw caused loss of p-coumaric, ferulic and diferulic acids from the cell walls, the loss being greater with the stronger alkalis. The loss of ferulic was greater than that of p-coumaric acid.     

Threshold Determination by Titration: A Markoff Chain Model

Threshold is often defined as that stimulus intensity which is correctly detected 50% of the time. A titration procedure increases the stimulus intensity by a fixed increment if the subject fails to detect the stimulus, and decreases the stimulus if it is detected. The mean stimulus intensity thus obtained is an estimate of threshold. The Markoff chain model developed here allows the mean and variance of the mean to be calculated for any specified stimulus values, number of trials, and distribution of the underlying variate. Examples are given to illustrate the effects of changing the experimental parameters and the underlying distribution. The titration mean was fairly insensitive to these changes.     

Major congeners of australian and imported brandies and other spirits as indicators of authenticity

The quantitative determination of the congeners methanol, n-propanol, ethyl acetate, i-butanol (2-methyl-1-propanol) and amyl alcohols (2-methyl-1-butanol and 3-methyl-1-butanol, which were not separated), was carried out on 61 Australian brandies, 61 French brandies and 50 wine distillates by gas chromatography. A comparison of the absolute amounts of congeners and their ratios (in the case of the C₃–C₅ alcohols) is presented in the light of several criteria of authenticity proposed by previous workers. Of these criteria, it was found that the amyl/i-butyl alcohol ratio and the i-butyl/n-propyl alcohol ratio were the most useful—on this basis, 11 French brandies (but no Australian brandy) were considered to be of suspect authenticity.     

Rectification at n-n GaAs:(Ga,Al)As heterojunctions

n-n Ga0.7Al0.3As: GaAs heterojunction structures have been grown by l.p.e., with 1 × 1015 cm-3 net carriers in the ternary. N/W profiling across the heterojunction shows an accumulation region on the GaAs side and a depletion region on the (Ga, Al)As side. I/V characteristics at room temperature show significant rectification.     

Photoelectrochemical solar cells using electrodeposited GaAs and AlSb semiconductor films

Electrodeposited GaAs and AlSb thin film semiconductors were prepared under various deposition conditions. Reasonable stoichiometry could be attained as revealed by EDAX studies. The best stoichiometry was obtained are Ga_1·04As_0·96 and Al_1·12Sb_0·88. The band gap of the GaAs and AlSb films was ∼1·5 eV and 1·6 eV respectively. The electrochemical and photoelectrochemical studies on these films are reported with different redox-couples in aqueous and non-aqueous medium.     

Empirical modeling of systematic spectrophotometric errors

Spectrophotometers, as electro-mechanical-optical devices, perform at a finite level of accuracy. This accuracy is limited by such factors as monochromator design, detector linearity, and cost. Generally, both the diagnosis and correction of spectrophotometric errors require a number of calibrated standard reference materials and considerable effort and commitment on the part of the user. A technique using multiple linear regression has been developed, based on the measurement of several suitably chosen standard reference materials, to both diagnose and correct systematic spectrophotometric errors, including photometric zero errors photometric linear and nonlinear scale errors, wavelength linear and nonlinear scale errors, and bandwidth errors. The use of a single chromatic ceramic tile to correct systematic errors improved the colorimetric accuracy of a set of chromatic and neutral tiles by a factor of two for a typical industrial-oriented spectrophotometer. Greater improvement can be achieved by increasing the number of tiles and performing a separate regression at each measured wavelength., These techniques have been extremely useful in improving inter-instrument agreement for instruments with similar geometry.     

Crystallographic evolution of microstructure in thin film processing: Part I. grain size distribution

Processing parameters and the resulting properties of a material are linked by the relationship between processing and microstructure. Characterizing the effect of processing variations on microstructure and determining its origin are essential to advanced material development. In this and a companion article, some readily applied techniques for producing quantitative data on grain size and shape, as well as grain and boundary crystallography, are described. The method described in Part I utilizes transmission electron microscopy and image analysis to measure grain size in large quantities (2000 to 3000 grains per sample), differentiated into orientation class subpopulation distributions. On application to Ni thin films produced by ion assisted deposition, the results have identified an orientation subpopulation that is predominantly responsible for the larger grain sizes observed in films grown under high ion flux. Larger grain size and the development of a preferred orientation have both been associated with increasing ion flux during growth, however, these results give the first experimental evidence connecting grain size and texture in these films.     

In Vitro-In Vivo Correlation of Indomethacin Release from Prolonged Release W/O/W Multiple Emulsion System

A prolonged release oral w/o/w multiple emulsion was formulated using hydroxypropyl methyl cellulose as thickening agent. The polymer when used in different proportions, controlled indomethacin release from the biphasic emulsion system. Double emulsification technique was used for formulation of the biphasic emulsion system. The stability of the emulsion was found to be inversely proportional to the drug release characteristics. The in vitro release of indomethacin followed diffusional path through the oil layer and through the polymeric oil. The in vivo release studies were carried out using rabbits as animal models. A good linear correlation was obtained between in vivo-in vitro drug release from such multiple emulsion system.