Stability of everyday memory in age-associated memory impairment: A longitudinal study.

Everyday memory performance was examined longitudinally in 2 groups of Ss meeting the diagnostic criteria for age-associated memory impairment (AAMI). One group of 157 participants in a drug trial for reversing memory loss in AAMI was tested over multiple sessions. The other group of 75 persons did not participate in a drug trial and thus was tested only twice. Both groups were retested for longitudinal follow-up about 4 yrs after initial session. Follow-up test performance remained fairly stable relative to initial performance in both groups. The drug study group showed large practice effects during the course of the drug studies, but these effects subsided after the drug studies' end. Implications regarding memory decline in the normal elderly and neuropsychological measurement issues are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Liquid–liquid extraction of a recombinant protein with reverse micelles

Recombinant cytochrome b₅ was extracted into the reversed micelle phase of an anionic surfactant (AOT) in octane and back-extracted to a final aqueous phase. The extraction of the protein was controlled by an electrostatic mechanism, since it was dependent on the global charge of the protein. This was directly demonstrated by experiments with native and mutant cytochromes obtained by site directed mutagenesis. The back-extraction of cytochrome b₅ to a fresh aqueous phase was decreased by factors that reduced the size of the water pool of the organic phase, such as high salt concentrations (1–2 mol dm^?3 NaCl) and low temperatures (4°C), probably because of an increase in a favourable interaction of this protein with the surfactant at closer distances.     

Oscillations in a bounded volume of reacting gas suspensate

Sverdlovsk. Translated from Fizika Goreniya i Vzryva, Vol. 27, No. 1, pp. 82–88, January–February, 1991.     

Influence of surface treatment on the photoelectrochemical behaviour of Y-Ba-Cu-O thin films

Y-Ba-Cu-O films with different surface treatments have been studied by photoelectrochemical and XPS measurements. The influence of etching by bromine in ethanol of these films has been followed by means of the electrochemical oxidation of ferrocene in an aprotic electrolyte. From the dependence of dark and photocurrent on etching time it is concluded that Y-Ba-Cu-O thin films on LaAlO₃ are covered by a 1, 1nm thick nonstoichiometric surface layer. The cathodic polarization of Y-Ba-Cu-O at -0,9 V vs. Ag/AgCl in acetonitrile/0,1 M lithium perchlorate leads to the formation of a lithium-containing, oxygen-enriched surface layer. The photoelectrochemical response of the reduced films is similar to that of cuprous oxide and passive layers on copper.     

'Multifrequency' location and clustering of sequence patterns from proteins

In previous work, we have shown that a set of characteristics, defined as (code frequency) pairs, can be derived from a protein family by the use of a signal-processing method. This method enables the location and extraction of sequence patterns by taking into account each (code frequency) pair individually. In the present paper, we propose to extend this method in order to detect and visualize patterns by taking into account several pairs simultaneously. Two 'multifrequency' methods are described. The first one is based on a rewriting of the sequences with new symbols which summarize the frequency information. The second method is based on a clustering of the patterns associated with each pair. Both methods lead to the definition of significant consensus sequences. Some results obtained with calcium-binding proteins and serine proteases are also discussed.     

Study of the polymerization of Mo(VI) in weakly acidic concentrated (10−2M) paramolybdate solutions using the Mo/Fe atomic ratio of the equilibrium iron molybdate precipitates

The polymerization of Mo(VI) is investigated using the Mo/Fe atomic ratio of the equilibrium precipitates of iron molybdates obtained with a small Fe(III) excess. The overall formation equation of isopolymolybdate ions is deduced which presents the state of molybdate ions as a function of pH and concentration of the Mo(VI) solution.     

Optical fiber up-tapers with index perturbations-performanceanalysis

The performance of step index up-tapers subjected to certain index perturbations in investigated by computer simulation. Concentric symmetric and asymmetric index profile perturbations as well as localized spherical, called regions bubbles, having a different index are studied. It is found that some low-valued perturbations of small scale size (less than a wavelength) do not alter the optical fiber performance. However, the amount of beam expansion in the up-taper may be ultimately limited by such perturbations. Excessive magnification in the presence of perturbations can cause a distortion of the quasi-Gaussian shape and symmetry of the pure step-index fundamental mode as well as increase the excess loss and degrade the lateral and axial displacement tolerance improvements of the up-tapers. For example, an index variation of Δn≈10^-5 in conjunction with a perturbation scale size of 40 μm can be detrimental. Bubble-type perturbations could also cause similar problems. A single 12.8-μm-diameter bubble with a relative index of -0.02, embedded in a 128-μm-diameter step index core with relative index of 0.5%, produced a 0.3-dB excess loss     

FSK heterodyne transmission experiments at 560 Mbit/s and 1 Gbit/s

Optical frequency-shift-keying (FSK) signals are obtained from directly modulated distributed feedback (DFB) semiconductor lasers. Experimental studies of the direct frequency modulation (FM) characteristics of the DFB lasers show a nonuniform FM response due to the competing effects of thermal modulation of the laser active region and carrier density modulation. Equalization of the signal current to the laser is employed to produce a flat FM response from 30 kHz to 1 GHz. Optical FSK transmission and heterodyne detection experiments at 560-Mbit/s and 1-Gbit/s are conducted at a wavelength of 1497 nm. Receiver sensitivities of -39 dBm at 560 Mbit/s and -37 dBm at 1 Gbit/s are obtained. Transmission through 100 km of single-mode fiber at 1 Gbit/s is achieved with no degradation in receiver sensitivity.