Stochastic approximation algorithms for the local optimization of functions with nonunique stationary points

The aim of this paper is the provision of a framework for a practical stochastic unconstrained optimization theory. The results are based on certain concepts of stochastic approximation, although not restricted to those procedures, and aim at incorporating the great flexibility of currently available deterministic optimization ideas into the stochastic problem, whenever optimization must be done by Monte Carlo or sampling methods. Hills with nonunique stationary points are treated. A framework has been provided, with which convergence of stochastic versions of conjugate gradient, partan, etc., can be discussed and proved.     

Conceptual Approach to Limiting-State Design of Foundation Beds for Structures

The need for use of nonlinear methods for analysis of bed settlements is demonstrated, where use of linear methods of the criteria p R results in an unfounded additional increase in p_u. Proceeding from the class of structures, it is recommended to determine the settlements using either special numerical solutions based on rigorous theories of plasticity, or closed time-tested engineering solutions with standard soil tests.     

A Charge-Analyzing Probe for Aerosol Flows

A charge-analyzing probe for sampling aerosol flows that has been developed allows the charges and masses of the positively charged, negatively charged, and neutral fractions to be measured. It has been used to characterize the tribo-charge state of fly ash dispersed into a dust tunnel facility used for precipitator research. Bipolar charge/mass (q/m) ratios in the range ±(10-50)?C/g are typically measured, depending on the ash sample and its size distribution. It is shown that large conducting particles can undergo a shuttle motion which leads to anomalously high q/m values.     

Recording the field of a flaw on a magnetic tape in tangential magnetization by successively applied oppositely oriented fields

Theoretical and experimental results are considered that explain the type of the signal from a flaw in a ferromagnetic object that is tangentially magnetized by successively applied oppositely oriented fields in the course of its magnetographic inspection.     

Impact of Substrate and Processing on Confinement of Nafion Thin Films

Thin films of ion‐conducting polymers are an important area of study due to their function in many electrochemical devices and as analogues for interfacial phenomena that occur in bulk films. In this paper, the properties of Nafion, a prototypical ionomer, are investigated as thin films (4 to 300 nm) on carbon, gold, and platinum substrates that are fabricated using different casting methods and thermal histories. Specifically, water uptake, swelling, and morphology are investigated by quartz‐crystal microbalance, ellipsometry, and grazing‐incidence X‐ray scattering to develop structure/property/processing relationships. For all substrates, as the films' thickness decreased, there is an initial decrease in swelling followed by a subsequent increase for film thicknesses below ≈20 nm due to a disordering of the film hydrophilic/hydrophobic structure. Decreased swelling and less structural order is observed on gold for spin‐cast films compared to self‐assembled films; the opposite effect is observed for films on carbon. The presented systematic data set and analyses represent a thorough study of the behavior of Nafion thin films on model substrates of interest in metal catalyst/carbon electrodes, and these insights help to elucidate the underlying polymer physics and confinement effects in these and related systems.     

Return current in large aperture electron-beam-excited KrF lasers

Results from a model for an e-beam excited KrF laser are presented, and the effects of return currents on plasma parameters and laser performance are discussed. The author finds that the joule heating caused by the return currents, expressed as a fraction of total power deposition, increases with increasing halogen density, increasing aperture size, increasing pressure, and decreasing power deposition. The return current electric field causes a decrease in the rate coefficients for dissociate recombination and attachment and an increase in the rate of multistep ionization. As a result, the electron density near the foil increases by more than tens of percentage points. The laser intensity in those regions also increases. These effects are practically important in lasers having apertures exceeding 1 m     

The interaction of human estrogen receptor with DNA is modulated by receptor-associated proteins

To better define the role of accessory protein as mediators of estrogen receptor (ER) function, we have used immuno-, steroid-, and site-specific DNA-affinity chromatography to identify and characterize proteins that associate with ER in extracts from ER-expressing Chinese hamster ovary (CHO-ER) cells. Two associated proteins [70 and 55 kilodaltons (kDa)] were observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis silver stain analysis of all three column eluates. Two additional proteins (45 and 48 kDa) were preferentially retained by the ER-specific DNA affinity column. The 70-kDa protein was subsequently identified by Western blot analysis as a heat shock protein (hsp70). The 55-kDa protein was identified by N-terminal microsequencing as a member of the protein disulfide isomerase family. The 48- and 45-kDa proteins remain unidentified. To determine the possible differential effects of estrogen agonists and antagonists on human (h) ER interaction with these proteins, CHO-ER cells were labeled with [35S]methionine in the presence of estradiol, 4-hydroxytamoxifen (OH-Tam; partial agonist/antagonist), or ICI 182,780 (complete antagonist). None of these ligands altered the pattern of associated proteins when hER complexes were isolated by adsorption to the vitellogenin A2 estrogen response element (ERE). However, when hER was isolated by immunoadsorption, a reduction in the level of associated hsp70 was observed following treatment with estradiol or OH-Tam, compared to no treatment or treatment with ICI 182,780. By gel retardation analysis, maximal interaction of affinity-purified hER with ERE occurred in the presence of all four associated proteins. Removal of the 48- and 45-kDa proteins and/or hsp70 resulted in a decrease in hER/ERE association, which could be restored by the addition of purified hsp70 and/or a mixture of the 48- and 45-kDa proteins. The increased stability of the restored complex was due primarily to an increase in the association rate of hER with ERE. These results suggest that accessory proteins may be required for maximal ER interaction with EREs and that estrogens and estrogen antagonists may promote differential retention of hsp70 in the presence or absence of a specific ERE.     

Magnetographic inspection of objects by means of their magnetization with a movable permanent magnet via a magnetic carrier. Magnetization schemes

Different magnetization schemes used for the magnetographic inspection of ferromagnetic products magnetized with a movable permanent magnet via a magnetic carrier placed on an inspected surface are analyzed. The most efficient schemes are selected.     

System of natural killer lymphocytes in Alzheimer's type dementias

Cytotoxic activity and quantity of natural killer (NK) lymphocytes were measured in 25 patients with Alzheimer's disease (AD), in 13 patients with senile dementia of Alzheimer's type (SDAT) and in 31 normals of different age (controls). In mentally healthy elderly individuals of the same age as the patients, functional activity of a subpopulation of NK lymphocytes was significantly decreased in comparison with healthy young people, meanwhile a number of these cells wasn't changed. In patients with AD and SDAT the tendency was found to increasing of functional activity of NK lymphocytes in comparison with elderly normals, which achieved the degree of significant differences only in SDAT patients with moderate dementia. Direct dependence of cytotoxic activity of NK lymphocytes on AD duration was determined. Such correlation was not observed in SDAT. This permitted to suppose a destructive influence of lymphocytes with increased cytotoxic activity on either CNS cells or their components in AD.     

Correlation between functional activity of lymphocytes in patients with Alzheimer''s dementia and their response to therapy

Three types of analog impedance converters based on operational amplifiers for differential measurements are outlined. The converters are easy-to-use and can find medical and biological applications.