Optimism and pessimism in optimised replay

The replay of task-relevant trajectories is known to contribute to memory consolidation and improved task performance. A wide variety of experimental data show that the content of replayed sequences is highly specific and can be modulated by reward as well as other prominent task variables. However, the rules governing the choice of sequences to be replayed still remain poorly understood. One recent theoretical suggestion is that the prioritization of replay experiences in decision-making problems is based on their effect on the choice of action. We show that this implies that subjects should replay sub-optimal actions that they dysfunctionally choose rather than optimal ones, when, by being forgetful, they experience large amounts of uncertainty in their internal models of the world. We use this to account for recent experimental data demonstrating exactly pessimal replay, fitting model parameters to the individual subjects’ choices.     

Exponential distribution of interimpulse current intervals in lipid bilayer membrane at phase transition temperature

The statistical analysis of current fluctuations in unmodified bilayer lipid membranes at the phase transition temperature was made. An exponential distribution of current fluctuations was revealed.     

Interfacial tension of aqueous biopolymer mixtures close to the critical point

Proteins and polysaccharides, being the main constructional materials in many biological structures, have a limited compatibility in aqueous media. At sufficiently high concentrations, they form water-in-water emulsions. Interfacial tension is an important parameter in such systems since it is a controlling factor in the morphology development during processing. In this work a rheo-optical methodology, based on the analysis of small angle light scattering (SALS) patterns during fibril break-up, is used to study the interfacial tension of water-sodium caseinate-sodium alginate systems located close to and relatively far from the binodal. The interfacial tension close to the critical point was approximately 10(-8) N/m, and it increased considerably, to a value of up to 5.2 x 10(-6) N/m farther from the critical point. For the scaling of the interfacial tension with the density difference between the phases, a scaling exponent of 3.1 +/- 0.3 was found, in agreement with the critical mean-field scaling exponent of 3.     

Spectral Analysis of Long Electroencephalographic Records

Spectral analysis of a 10-min electroencephalogram (EEG) record has made it possible to describe the behavior of EEG rhythms as a dynamic spectrum and find a distinct periodic pattern in this behavior. The data on the dynamic spectra of long EEGs offer a new insight into the estimation of the stability of EEG electrical processes in healthy subjects, inter- and intrahemispheric relationships between the electrical activities of different cortical regions, and estimation of phase relations, which were previously performed on the basis of comparison between single EEG spectral patterns.     

Characteristics of EEG signs of anxiety in human

Influence of anxiety (tested by Luscher) on the spatial organization of brain electrical activity was studied using multichannel EEG recording. In subjects with a high-level of anxiety, the level of coherence and spectral power of some high-frequency EEG components was higher in the parieto-temporal regions of both hemispheres than that in the opposite group. Solving the inverse problem (classification of individuals with one of the groups) made it possible to work out the criteria of automated evaluation of the anxiety level at the preclinic state of neuropsychic disorders. The EEG signs of the influence of increased anxiety on psychophysiological and cognitive processes and autonomic functions were analyzed. The EEG signs of increased anxiety in animals (rats) and humans were compared and some similarity of the spatial-frequency organization was revealed. The main difference consists in a greater activation of the left parieto-temporal area in humans, which is interpreted as a morphofunctional basis of verbalization of anxiogenic stimuli.     

Mobilization of a cryptic plasmid from the melioidosis pathogen in heterologous species of microorganisms

Cryptic plasmids with different molecular weights have been detected in B. pseudomallei strains. Mobilization of B. pseudomallei plasmid DNA in heterologous B. mallei species was performed by the conjugate plasmid RP1::Tn10. Possibility of detecting phenotypical characteristics of plasmids and behavior of B. pseudomallei non-chromosomal replicons in B. mallei have been determined.     

Interactions and compatibility of ribuloso-1,5-bisphosphate carboxylase/oxygenase from alfalfa with pectin in aqueous medium

HPLC, dynamic light scattering, CD- and fluorescent spectroscopy, and phase analysis methods are used to study the effect of Coulomb and non-Coulomb interactions between alfalfa rubisco and pectin on their thermodynamic compatibility. In the acid region of pH, water insoluble interpolymer complexes stabilized by both the Coulomb and non-Coulomb bonds are formed. In the neutral and alkaline regions, the complexes soluble in water are formed via non-Coulomb bonds, due to both the hydrophobic interaction involving the ester groups of pectin and the hydrogen bonding between dissimilar molecules. The compatibility of these biopolymers is sensitive to the esterification degree of pectin. With the latter increasing, compatability increases at neutral pH, but decreases considerably in the acidic region.     

Two common nonsynonymous paraoxonase 1 (<Emphasis Type="Italic">PON1</Emphasis>) gene polymorphisms and brain astrocytoma and meningioma

Background  

Human serum paraoxonase 1 (PON1) plays a major role in the metabolism of several organophosphorus compounds. The enzyme is encoded by the polymorphic gene PON1, located on chromosome 7q21.3. Aiming to identify genetic variations related to the risk of developing brain tumors, we investigated the putative association between common nonsynonymous PON1 polymorphisms and the risk of developing astrocytoma and meningioma.