Organic Acid Adsorption on Lead Titanate Surfaces

Several carboxylic acids were adsorbed on the surface of lead titanate. The total amount of adsorbed acid was determined and characterized by diffuse reflectance infrared Fourier transmission spectroscopy (DRIFTS). The acids were found to be chemisorbed on the lead titanate surface by a metal carboxylate bond. This bond forms by reaction between surface hydroxyls and the organic acid functional group. The amount of adsorbed species per unit surface area varied with each carboxylic acid studied and generally correlated with the size of the individual molecules. The experiments also demonstrate an application of a sensitive method for carbon analysis, oxygen-based coulombic titration.     

Resolution correction for molecular weight averages from GPC

The method of Hamielec and Ray for correcting GPC molecular averages is discussed. It is shown that this method can be combined with the resolution index concept of Smith and Feldman to provide a simple accurate correction method. Practical application of the method to four different column combinations is discussed. Three of the combinations are typical Styragel column combinations, and they are very similar in their correction requirements. The fourth combination employed less gel with resultant higher flow rates and much shorter residence times. It required a larger correction factor, but even so, only a 17% correction to the weight-average or number-average molecular weight was required.     

Beta decomposition of (HFxZr1_x)80Nb20 ternary alloys

The processes of beta decomposition have been examined in ternary alloys of the form (Hf_xZr_1-x)₈₀Nb₂₀ to determine the influence of Hf additions to a basic Zr₈₀Nb₂₀ composition. In the chill cast condition, Hf additions have been found to decrease the temperature coefficient of electrical resistivity from a value of-0.0015 pct/K for the binary Zr8oNb2o alloy to a value of-0.011 pct/K for a (Hf_xZr_1-x)₈₀Nb₂₀ ternary alloy. This change is explained in terms of the bcc lattice instability typical of Ti, Zr, and Hf alloys. The Hf additions enhance the kinetics of ω-phase precipitation during aging at 648 K. The aging of a (Hf₀₅Zr₉₅)₈₀Nb₂₀ alloy for 12 h results in the precipitation of a high volume fraction of cuboidal shaped co-phase particles. A phase separation which results in the formation of solute lean discs (β₁) occurs together with the precipitation of the ω-phase. These discs formed both randomly within the matrix and heterogeneously along dislocations and at grain boundaries.     

The Application of Pattern Recognition Techniques to the Contingent Negative Variation for the Differentiation of Subject Categories

Pattern recognition techniques and the statistics of directional data have been applied to a repetitive waveform to differentiate between subject categories. Normal subjects and Huntington's Chorea patients were distinguished by comparing the patterns in the summarized results of statistical tests applied to the Fourier harmonics of their contingent negative variation (CNV) responses, by the consecutive phase angle variations of the first harmonic of their CNV's, and by their different averaged CNV's. A logic algorithm which may provide the basis of computerized diagnosis, or even prediction of the condition, is described.     

A comparison of the carbon-13 n.m.r. spectra of solid coals and their liquids obtained by catalytic hydrogenation

High-volatile bituminous and lignite coals have been studied by means of carbon-13 n.m.r. employing cross-polarization and magic-angle-spinning techniques. The solids spectra have been compared to those of the coal-derived liquids. By artificially broadening the high-resolution spectra of the liquids, a striking similarity in line shape and position is observed when the liquid spectra are compared with those of the corresponding solid coal. It is noted however that certain bands visible in the solid are no longer present in the liquefied state. The significance of these results is discussed in terms of carbon skeletal structures present in the solids but not in the liquids.     

Graves' ophthalmopathy

Ophthalmopathy develops in about 30% of patients who have Graves' disease. The pathogenesis, like that of the hyperthyroidism, is probably autoimmune in nature. The eye manifestations are diverse and include lid lag, soft tissue swelling, proptosis, corneal damage, diplopia, and optic neuropathy. The natural history is benign in 90% of patients, with gradual improvement over time. Therapeutic options include corticosteroid therapy, radiation, and surgical treatment. The last is usually the therapy of choice for severe or disfiguring ophthalmopathy.     

Mattesia trogodermae infection rates as influenced by mode of transmission, dosage and host species

Specificity of infection by Mattesia trogodermae Canning was tested on six species of Trogoderma. Exposure of insects to similar numbers of spores indicated infections are always fatal in T. sternale Jayne, T. simplex Jayne, T. glabrum (Herbst) and T. inclusum LeConte. Rates of mortality (LT₅₀'s) were similar among the susceptible species and infection always reached 100 per cent in exposed insects. Trogoderma grassmani Beal and T. variabile Ballion were not infected at the dosages studied.

When eggs were seeded on to medium containing spores, the number of adults produced from such cultures was reduced by 50 per cent with an inoculation rate of 50 spores/g medium. Five thousand spores/g were necessary to infect all larvae before reaching the adult stage, however, this effect could be achieved with fewer total spores per jar if they were concentrated in the upper 1/5 of medium in the culture container. Infected larvar, when introduced into cultures, also cause infection of newly hatched larvae and subsequent reduction of adult production. A single infected larva reduced adult production by 25 per cent; 100 per cent infection of larvae was effected with 25–50 infected larvae per 50 g medium.

Adult T. glabrum males externally contaminated with Mattesia were able to transmit infective spores to females. Spore presence on the adults was determined by feeding the freeze-killed insects to larvae and inspecting the larvae for infection several weeks later. Male beetles were initially contaminated by being drawn to a corrugated cardboard inoculation device treated with pheromone ((Z)-14-methyl-8-hexadecen-1-ol) and dusted with Mattesia powder. Pheromone-baited inoculation devices resulted in contamination of 96 per cent of test insects placed in the arena whereas only 56 per cent picked up spores from inoculation devices containing only Mattesia spores (no pheromone).