The incubation time for hole formation due to electromigration in Al and Al/Cu/Al thin films

Transmission electron microscope observations of hole formation in Al and Al/Cu/Al thin film conductors carrying high current densities have revealed the presence of an incubation period for hole growth. The temperature dependence of this incubation period for pure aluminum conductors has been determined and found to follow an Arrhenius relationship with an activation energy of 0.55 ev ± 0.1 ev.     

Synthesis of cascaded multiple-loop feedback systems with large plant parameter ignorance

In a cascaded plant with n sensing points, n independent feedback loops are available to achieve quantitative sensitivity specifications. The optimum design is defined as that which achieves this with minimum net effect, of the n sensor noise sources, at the plant input. A design procedure is presented wherein one works backwards step by step from the system output, designing each loop function L_i almost as if the remaining loops (L_i+j, j>0) are perfect. Even in large plant ignorance problems, only the outer loop L_i may be large over some frequency range. In general |L_i|_max < 1, i ≠ 1 and |L_i+1|_max < |L_i|_max. Each L_i has only one distinct frequency range say at ω_{c, i} requiring trade-off between L_i and L_i+1. Only in this range is significant design effort required. However, ω_{c, i+1} >ω_{c, i} so the primary price paid is in the steadily increasing “bandwidth” of each loop. The design procedure is highly transparent with strong universalistic features, permitting the use of universal design curves.     

Teratogenic and embryotoxic activity of several 2,4-diaminopyrimidine derivatives

The degree of teratogenic and embryotoxic effects is dependent not only on the period of gestation and the agent dosage but also on the chemical structure of its molecule. In the series of derivatives of 2,4-diamino-5-phenylpyrimidine with different length of the alkul radical in the 6 position the preparation with ethyl group has the greatest injuring effect. Thus, the structural distinctions in the molecules of pharmacological agents are responsible for the selective toxicity of drugs in relation to mammalian embryos.     

On the identification of warded-off mental contents: An empirical and methodological contribution.

The basic assumption behind psychoanalytic psychotherapy is that mental contents that were once warded off come to emerge in the course of a successful treatment. This paper focuses on specific contents which a male patient in his mid-20's became aware of during a psychoanalytic treatment. Study 1 describes the method for identifying warded-off contents: Themes were identified that emerged for the 1st time between Hours 41 and 100; then 20 clinicians read the process notes of the 1st 10 hrs of treatment and judged which of the newly emerging themes had previously been warded off. The judges' ratings were highly reliable and case specific. Studies 2 and 3 validated the ratings (a) by assessing the patient's discomfort when warded-off themes emerged and (b) by examining relevant changes in the patient's memories of early events. Finally, Study 4 explored certain conditions involving the patient-therapist interaction that facilitate the emergence of warded-off contents. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of the quasifree charge-exchange reaction for 12C and 54Fe

Serotonin (5-hydroxytryptamine, 5-HT) in blood is stored in platelets and has vascular and platelet stimulating effects when released into plasma. Accurate measurements of 5-HT in plasma are complicated by inadvertent platelet activation causing sampling artifacts and by analytical problems when determining trace levels. We developed an assay for plasma 5-HT based on solid-phase extraction (Sep-Pak C18), aqueous acetylation, pentafluoropropionylation, and negative ion chemical ionization gas chromatography-mass spectrometry. The method was able to recover 5-HT from plasma by > 90% and to quantitate with a precision of 7.5% at a level of 0.5 nmol/l. It was used to define blood sampling and sample handling procedures giving low and consistent values for 5-HT. A good blood sampling technique, adequate platelet stabilization in the test tube, and rapid high speed centrifugation of the blood resulted in low plasma levels of both 5-HT and beta-thromboglobulin (a platelet release product). Using these procedures plasma 5-HT levels in healthy volunteers were found to be 0.77 +/- 0.38 (mean +/- S.D.; range 0.27-1.49) nmol/l (n = 18), which is 4-100-fold lower than previously reported values.     

The cytogenetic disorders in the people who took part in the cleanup of the sequelae at the Chernobyl Atomic Electric Power Station and who lived continuously in areas with an unfavorable ecological situation

Cytogenetic disturbances are manifested now in persons who liquidated aftereffects of the Chernobyl disaster. The character and course of the disturbances depend on the ecological conditions of the region where liquidators live at present. Examination of a group of liquidators with nerve-psychopathologic disorders and accompanying somatic pathology has revealed the presence of cytogenetic disturbances, mainly of the chromosome aberration type. At the same time, in persons who live under conditions of high environment pollution with ejections of industrial enterprises, the number of chromatid aberrations increases, which may be a result of action of chemical mutagens. A tight correlation is revealed between the level of cytogenetic disorders in lymphocytes and expressivity of the secondary immunodeficiency. Elimination of lymphocytes with unstable chromosome aberration is delayed when ecological pollution of the biosphere reaches the high level.     

Clinical trials comparing two treatment policies: which aspects of the treatment policies make a difference?

We discuss pragmatic clinical trials with survival endpoints in which subjects commonly change treatment during follow-up. Suppose that an intention-to-treat (ITT) analysis shows a significant difference between the randomized groups. We may want to ask questions about the reason for such a difference in outcome between randomized groups: for example, was the difference due to different policies for change to a third more beneficial regime? We address such questions using the semi-parametric accelerated life models of Robins, which exploit the randomization assumption fully and avoid direct comparisons of possibly differently selected subgroups. No assumption is made about the relationship of treatment actually prescribed to prognosis. A sensitivity analysis, using a range of plausible values for the causal effect of a covariate, estimates the contrasts between randomized groups that would have been observed if the covariate had universally been 0. The main technical problem is in dealing with censoring, for the method requires different degrees of recensoring for different values of the causal effect, and this can lead to estimates of low precision. The methods are applied to a randomized comparison of two anti-hypertensive treatments in which approximately half the subjects changed treatment during follow-up. Various time-dependent covariates, representing patterns of side-effects and treatments, are used in the model. We find that the observed difference in cardiovascular deaths between the randomized groups cannot be explained in this way by their different covariate patterns.