Probing the limits: ultraslow diffusion and heterogeneous electron transfers in redox polyether hybrid cobalt bipyridine molten salts

This paper describes microelectrode voltammetry measurements of self-diffusion coefficients and of heterogeneous Co(II/III) electron-transfer rate constants (ko) in undiluted molten salts of three cobalt tris(bipyridine) perchlorate complexes in which the bipyridine ligands are "tailed" with poly(propylene oxide) and poly(ethylene oxide) oligomers. The self-diffusion coefficients are measured with potential step chronoamperometry and range from 10(-12) to 10(-17) cm2/s, while the quasi-reversible reaction rate constants are measured using cyclic voltammetry and small potential steps and range from 10(-7) to 10(-12) cm/s. The ko measurements are unusual in that when rate constants become smaller, the reaction remains quasi-reversible, because of concurrently decreasing self-diffusion rates. The measurements are, furthermore, accomplished in the face of uncompensated resistances that range from mega- to gigaohms, which is made possible by the combination of microelectrode properties and small diffusivities. The melt in which self-diffusion and ko values are smallest is at a temperature below its nominal glassing transition and in the regime of molecule-scale diffusion profiles.     

Effects of oleic acid-induced pulmonary edema on lung mechanics

In 25 rabbits anesthetized with pentobarbital sodium and paralyzed with succinylcholine chloride, we investigated the contributions of four factors that might cause the decreased static lung compliance found in oleic acid-induced pulmonary edema: 1) foam, 2) accumulation of fluid in the interstitial spaces, 3) loss of ventilatable units secondary to alveolar flooding, and 4) increased surface tension. Pulmonary edema, reflected by a 115% increase in mean post-mortem extravascular bloodless lung water content, decreased compliance 47% and tripled alveolar-arterial PO2 difference. Removing foam by degassing did not affect compliance measurements. Filling the lungs with saline caused similar changes in control and edematous animals. Because the 38% decrease in functional residual capacity was largely attributable to water accumulation, we concluded that loss of ventilatable units accounted for virtually all the decreased static lung compliance. The role of increased surface tension could not be determined directly but was considered relatively less important.     

Structures of five mutants of toxic shock syndrome toxin-1 with reduced biological activity

The three-dimensional structures of five mutants of toxic shock syndrome toxin-1 (TSST-1) have been determined. These mutations are in the long central alpha helix and are useful in mapping portions of TSST-1 involved in superantigenicity and lethality. The T128A, H135A, Q139K, and I140T mutations appear to reduce superantigenicity by altering the properties of the T-cell receptor interaction surface. The Q136A mutation is at a largely buried site and causes a dramatic change in the conformation of the beta7-beta9 loop which covers the back of the central alpha helix. As this mutation has the unique ability to reduce the toxin's lethality in rabbits while retaining its superantigenicity, it raises the possibility that this rear loop mediates the ability of TSST-1 to induce lethality and suggests a route for producing nonlethal toxins for therapeutic development.     

Patterns of self-initiated smoking cessation among young adults.

Applied the cyclic-stage model of self-initiated smoking cessation by J. O. Prochaska and C. C. DiClemente (1984) to data on 3,179 young adults (aged 17–21 yrs) to determine the cross-sectional distribution of stages and the frequency and pattern of changes among stages over time. Compared to older adults, the distribution of the stages differed substantially. There were twice as many relapsers and only half as many maintainers among young adults. One-yr changes in stages were examined using a static model that did not take into account the cyclic nature of the change process and a dynamic model that did. Both models, especially the dynamic model, suggested more movement among stages in younger than in older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Planning for the appropriate analysis in school-based drug-use prevention studies.

School-based drug-use prevention studies often apply interventions to entire schools. A major problem for these studies results from the intragroup dependence often seen when intact social groups are assigned to study conditions. Analysis of data from 2 such studies revealed intraclass correlation coefficients between 0.02 and 0.05 for common drug use measures. Because even such modest intragroup dependence can invalidate the traditional fixed-effects analyses, researchers should adopt alternative methods that acknowledge this dependence. These alternative methods are reviewed, and appropriate methods for computing sample size requirements are illustrated. Investigators should consider these analysis issues when planning future studies, because the number of schools required for an unbiased analysis may be substantially greater than for the traditional methods. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Misuses of the multiple sufficient causal scheme as a model of naive attributions: A case of mistaken identity.

Much current work in attribution theory presumes that in multicausal situations, naive attributions are often characterized by the multiple sufficient (MS) causal scheme. The present research examined whether the MS scheme or an alternate model, the variant-effect (VE) scheme, better characterizes naive attribution. The VE scheme is a generalization of H. H. Kelley's (1972) graded-effects scheme and, in contrast to the MS scheme, reflects a belief in the conservation of causal energy. 108 5–12 yr olds received a series of social inference problems. In each problem, Ss gave base-rate estimates of an event and also made attributions of the likelihood that the event occurred after hearing that a related effect occurred in the presence of another cause. Three critical tests consistently disconfirmed use of the MS scheme and supported use of the VE scheme. Results indicate increasing use of the VE scheme with development. Preference for a VE scheme over an MS scheme suggests a picture of a naive attributor who is perceptually sophisticated but operationally naive—accepting causal simplicity rather than entertaining the possibility of causal indeterminacy. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Asthma and rhinosinusitis

Allergic rhinoconjunctivitis and asthma are becoming more common in industrialized societies, particularly in the second and third decades of life, when those affected are at a vital stage of their education and career. It is therefore of paramount importance that the treatment options available be effective, improve quality of life, and above all, they must be without any significant unwanted effects. National and international guidelines for the treatment of both allergic rhinitis and asthma have been released recently that put forward recommendations based on an extensive evidence-based review of the literature for the care of these diseases that would meet these goals of disease management.     

Computer security: Observations on the state of the technology

Far more progress has been made in introducing new technology for audit, control and security over the past five years than has been in applying it. The lag in application stems in part from the lack of knowledge about the technology. This paper will address advances in share storage, priveleged instructions, use of registers, authorization mechanisms, journals and logs, end-user authentication, external controls, cryptography, transaction-driven systems and application development. For each of these categories it will address the audit, control and security uses of the advances.     

Continuous wear measurement by on-line ferrography

An on-line Ferrograph was used to monitor the wear rates of oil-lubricated ball-bearings. Periodically, the test bearings were also removed from the test stand and cleaned and weighed on an analytical balance.A comparison of the mass loss data obtained by each of these two methods showed that the Ferrograph readings did provide on-line quantitative wear data for each individual test. However, the rates at which the ball-bearings wore were not consistent from test to test. For the four ball-bearings that were evaluated, plots of the Ferrograph concentration readings versus bearing mass loss gave slopes that varied between 1.1 and 2.5. Nevertheless, the results showed that semiquantitative data on the wear rates of machine components could be obtained with this on-line instrumentation.     

Harmonic suppression in surface-acoustic-wave devices using jogged multistrip couplers

A simple technique is presented for the suppression of unwanted harmonic responses in surface-acoustic-wave devices by the provision of a geometrical jog in one track of a track-changing multistrip coupler.