Verbal and visuospatial performance in male alcoholics: A test of the premature-aging hypothesis.

Tested the premature-aging hypothesis of generalized dysfunction, using a paired-associate learning test that has separate verbal and visuospatial subtests of the same structure and method. Ss were 36 hospitalized White male chronic alcoholics (mean age 42.4 yrs), 36 control Ss (mean age 42.5 yrs), and 24 elderly Ss (mean age 71.4 yrs). Ss were also administered the Shipley Institute of Living Scale for Measuring Intellectual Impairment and Memory-for-Designs test. Results show that elderly control Ss performed significantly worse than middle-aged control Ss on both learning subtests. For Ss between 30 and 80 yrs of age, increasing age resulted in increasing errors. According to the generalized dysfunction hypothesis, the performance of alcoholics should be similar to that of the elderly, showing impairment compared to control Ss on both learning tests. However, alcoholics performed at the same level as the middle-aged control Ss on verbal learning and were significantly poorer on visuospatial learning. The generalized dysfunction version of the premature-aging hypothesis for performance of alcoholics on neuropsychological tests was not supported. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Denuded zones, diffusional creep, and grain boundary sliding

The appearance of denuded zones following low stress creep in particle-containing crystalline materials is both a microstructural prediction and observation often cited as irrefutable evidence for the Nabarro-Herring (N-H) mechanism of diffusional creep. The denuded zones are predicted to be at grain boundaries that are orthogonal to the direction of the applied stress. Furthermore, their dimensions should account for the accumulated plastic flow. In the present article, the evidence for such denuded zones is critically examined. These zones have been observed during creep of magnesium, aluminum, and nickel-base alloys. The investigation casts serious doubts on the apparently compelling evidence for the link between denuded zones and diffusional creep. Specifically, denuded zones are clearly observed under conditions that are explicitly not diffusional creep. Additionally, the denuded zones are often found in directions that are not orthogonal to the applied stress. Other mechanisms that can account for the observations of denuded zones are discussed. It is proposed that grain boundary sliding accommodated by slip is the rate-controlling process in the stress range where denuded zones have been observed. It is likely that the denuded zones are created by dissolution of precipitates at grain boundaries that are simultaneously sliding and migrating during creep. This article is based on a presentation made in the workshop entitled “Mechanisms of Elevated Temperature Plasticity and Fracture,” which was held June 27–29, 2001, in Dan Diego, CA, concurrent with the 2001 Joint Applied Mechanics and Materials Summer Conference. The workshop was sponsored by Basic Energy Sciences of the United States Department of Energy.     

Precipitation and densification of magnetic iron compounds from aqueous solutions at room temperature

The advantages of generating stable and compact spinel-type precipitates from aqueous solutions at ambient temperature, instead of the amorphous and voluminous hydroxides obtained by conventional treatment of effluents are supported by experimental evidence. As a first step, the study of magnetite formation by controlled aerial oxidation of ferrous solutions at ambient temperature was considered. The parameters studied were: aerial oxidation intensity, precipitation pH, SO₄²⁻ concentration, initial Fe²⁺ concentration and aging of the sludges. The results suggest a close relation between precipitation pH and the kinetics of conversion of intermediate green rust-II into γ-FeOOH and/or Fe₃O₄. A precipitation pH between 10 and 11 and a well-controlled oxidant environment achieved by a moderate aeration of the solutions promoted suitable physical and chemical stability characteristics of quickly generated magnetite at ambient temperature. Furthermore, the minimum concentration of ferrous ions conducive to magnetite formation will be limited by the preexistent amount of dissolved oxygen in the starting solutions. Generated information was related to a laboratory-scale simulation of the `Recycle Process', but applied to the generation and densification of magnetic sludges. The stability conditions of iron precipitates allowed a better understanding of those transformations that occur in the stages of this process: aerated alkaline precipitation, solid/liquid separation, chemical conditioning of settled solids and their recycling to the precipitation stage.     

Design of computer experiments applied to modeling of compliant mechanisms for real-time control

This article discusses the use of design of computer experiments (DOCE) (i.e., experiments run with a computer model to find how a set of inputs affects a set of outputs) to obtain a force–displacement meta-model (i.e., a mathematical equation that summarizes and aids in analyzing the input–output data of a DOCE) of compliant mechanisms (CMs). The procedure discussed produces a force–displacement meta-model, or closed analytic vector function, that aims to control CMs in real-time. In our work, the factorial and space-filling DOCE meta-model of CMs is supported by finite element analysis (FEA). The protocol discussed is used to model the HexFlex mechanism functioning under quasi-static conditions. The HexFlex is a parallel CM for nano-manipulation that allows six degrees of freedom (x, y, z, θ _x , θ _y , θ _z ) of its moving platform. In the multi-linear model fit of the HexFlex, the products or interactions proved to be negligible, yielding a linear model (i.e., linear in the inputs) for the operating range. The accuracy of the meta-model was calculated by conducting a set of computer experiments with random uniform distribution of the input forces. Three error criteria were recorded comparing the meta-model prediction with respect to the results of the FEA experiments by determining: (1) maximum of the absolute value of the error, (2) relative error, and (3) root mean square error. The maximum errors of our model are lower than high-precision manufacturing tolerances and are also lower than those reported by other researchers who have tried to fit meta-models to the HexFlex mechanism.     

Comparative diagnostic accuracy of the Halstead-Reitan and standardized Luria-Nebraska neuropsychological batteries in a mixed psychiatric and brain-damaged population.

Compared the diagnostic accuracies of the Halstead-Reitan Neuropsychological Test Battery and the standardized Luria-Nebraska Neuropsychological Test Battery in 23 brain damaged and 24 psychiatric adults whose mean age was 35.25 yrs. All Ss were given both tests and classified as either brain-damaged or psychiatric by experienced raters. The hit rates obtained using the different batteries were comparable (approximately 80%) and in line with those obtained in previous research. It is concluded that the standardized Luria-Nebraska battery appears promising. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

ELECTRODE FUNCTION (PH RESPONSE) OF THE SODA-SILICA GLASSES*

A scries of Na₂O-SiO₂ glasses was studied for durability, hygroscopicity, glass-electrode function, and apparent response to [Na ⁺]. These glasses showed three distinct regions of durability characteristics at pH 4.6: (1) below 81% of SiO₂, where the glass was carried into solution; (2) between 81 and 89.5% of SiO₂, where differential solution of the constituents of the glass left a swollen silica-rich layer; and (3) a region in which greatly reduced attack was indicated. Glass electrodes of low silica content having poor chemical durability and high hygroscopicity exhibited large voltage departures approaching the values of a “punctured” mercury-filled electrode and a calomel half cell. The apparent response to [Na⁺] ranged from 9 to 339 mv. per pNa for the glasses of 82.6 and 56.6% of SiO₂, respectively.     

ESR study of reactions of cellulose with ·OH generated by Fe+2/H2O2

It was demonstrated by ESR spectroscopy that the Fe⁺²/H₂O₂ system gave a reactive species which generated an ESR triplet spectrum or sorbitol similar to that generated by hydroxyl radicals from the Ti⁺³/H₃O₂ system. An ESR spectrum was obtained for the hydroxyl radicals generated by the latter system. However, the lifetime of hydroxyl radicals, generated by the Fe⁺²/H₂O₂ system, was apparently very short, and an ESR spectrum for the hydroxyl radicals, generated by this system, was not observed. The Fe⁺²/H₂O₂ system also generated triplet spectra with cotton cellulose I, cotton cellulose II, and microcrystalline cellulose, suggesting that a hydrogen atom had been abstracted from the hydroxyl group on carbon C₆, or possibly the hydrogen atom on carbon C₅. The ESR spectrum generated on microcrystalline cellulose was less intense than those generated on cellulose I and II. On initiation of graft polymerization of the activated cellulose with acrylonitrile, the triplet spectrum disappeared and was replaced by two strong singlet spectra. One of the singlet spectra was likely generated on carbon C₁ or C₄ on depolymerization of the cellulose molecule, and the other was probably generated on the end of the growing polyacrylonitrile molecular chain. The absence of a triplet spectrum gave direct evidence for the order in which the acrylonitrile monomer was being grafted onto the cellulose molecule. The mechanisms proposed by Haber and Weiss for the reactions generated in the Fe⁺²/H₂O₂ system were generally supported.     

Glycerine distillation

This paper describes the method of operation and results secured with the Continuous Process of Glycerine Distillation. Improved results in quality, yield and cost of production of distilled glycerine is due to the continuous operation, with high vacuum, low temperature and continuous salt removal. Presented at the Twelfth Fall Meeting of the American Oil Chemists' Society, Chicago, Ill., October 6–7, 1938.