Structure, Morphology, and Permeability of Cellulose Films

The work is focused on the study of the influence of the cellulose type and processing parameters on the structure, morphology, and permeability of cellulose films. The free volume of the cellulose films was evaluated by the sorption of n-decane, which is a non-solvent for cellulose. The structural features of the membranes and their morphology were studied using X-ray diffraction, IR spectroscopy, SEM, and AFM methods. The characteristic features of the porous structure and properties of cellulose films regenerated from cellulose solutions in the N-methylmorpholine-N-oxide (NMMO) and cellophane films were compared. Generally, cellulose films obtained from solutions in NMMO have a higher permeability and a lower rejection (as measured using Orange II dye) as compared to cellophane films. It was also found that the cellulose films have a higher ultimate strength and modulus, whereas the cellophane films are characterized by higher elongation at break.

Polymeric Membranes for Oil-Water Separation: A Review

This review is devoted to the application of bulk synthetic polymers such as polysulfone (PSf), polyethersulfone (PES), polyacrylonitrile (PAN), and polyvinylidene fluoride (PVDF) for the separation of oil-water emulsions. Due to the high hydrophobicity of the presented polymers and their tendency to be contaminated with water-oil emulsions, methods for the hydrophilization of membranes based on them were analyzed: the mixing of polymers, the introduction of inorganic additives, and surface modification. In addition, membranes based on natural hydrophilic materials (cellulose and its derivatives) are given as a comparison.

[Correlation between Sensory Gating P50, Mismatch Negativity, and Reaction Time]

This paper is about the correlation pre-attentive processes, such as P50 sensory gating (SG P50) and mismatch negativity (MMN) with each other and with sensorimotor reaction time (RT). SG P50 data were obtained in the standard paired-click paradigm, MMN was measured in the passive odd-ball paradigm sensorimotor reaction time was studied in an active odd-ball paradigm. Was obtained positive correlation sensory gating P50 with amplitude mismatch negativity, amplitude mismatch negativity with sensorimotor reaction time, sensory gating P50 with sensorimotor reaction time.

[THE INFLUENCE OF FATIGUE ON THE SENSORY GATING TEMPORAL PARAMETERS]

The aim of the study was to investigate the influence of central fatigue and motor activity on sensory gating characteristics. The P50 component in a standard paired-click paradigm was used as a sensory gating index. The main attention was devoted to the P50 peak latency change in the fatigue development. It was found that the sustained muscle load leading to the fatigue development significantly reduced sensory gating and the P50 peak latency in response to the second stimulus of the pair. This may be due to the inhibitory process suppression underlying the sensory gating in the development of central fatigue.

[Perception features of emotional intonation of short pseudowords]

Reaction time and recognition accuracy of speech emotional intonations in short meaningless words that differed only in one phoneme with background noise and without it were studied in 49 adults of 20-79 years old. The results were compared with the same parameters of emotional intonations in intelligent speech utterances under similar conditions. Perception of emotional intonations at different linguistic levels (phonological and lexico-semantic) was found to have both common features and certain peculiarities. Recognition characteristics of emotional intonations depending on gender and age of listeners appeared to be invariant with regard to linguistic levels of speech stimuli. Phonemic composition of pseudowords was found to influence the emotional perception, especially against the background noise. The most significant stimuli acoustic characteristic responsible for the perception of speech emotional prosody in short meaningless words under the two experimental conditions, i.e. with and without background noise, was the fundamental frequency variation.

[Perception of emotional intonation of noisy speech signal with different acoustic parameters by adults of different age and gender]

The listener-distinctive features of recognition of different emotional intonations (positive, negative and neutral) of male and female speakers in the presence or absence of background noise were studied in 49 adults aged 20-79 years. In all the listeners noise produced the most pronounced decrease in recognition accuracy for positive emotional intonation ("joy") as compared to other intonations, whereas it did not influence the recognition accuracy of "anger" in 65-79-year-old listeners. The higher emotion recognition rates of a noisy signal were observed for speech emotional intonations expressed by female speakers. Acoustic characteristics of noisy and clear speech signals underlying perception of speech emotional prosody were found for adult listeners of different age and gender.

[Influence of human personal features on acoustic correlates of speech emotional intonation characteristics]

Comparative study of acoustic correlates of emotional intonation was conducted on two types of speech material: sensible speech utterances and short meaningless words. The corpus of speech signals of different emotional intonations (happy, angry, frightened, sad and neutral) was created using the actor's method of simulation of emotions. Native Russian 20-70-year-old speakers (both professional actors and non-actors) participated in the study. In the corpus, the following characteristics were analyzed: mean values and standard deviations of the power, fundamental frequency, frequencies of the first and second formants, and utterance duration. Comparison of each emotional intonation with "neutral" utterances showed the greatest deviations of the fundamental frequency and frequencies of the first formant. The direction of these deviations was independent of the semantic content of speech utterance and its duration, age, gender, and being actor or non-actor, though the personal features of the speakers affected the absolute values of these frequencies.

[Experimental formation of visual-auditory associations in phoneme recognition]

In this study we investigated a question about a possibility to form auditory-visual associations during discrimination of speech sounds (phonemes) when they presented simultaneously with visual stimuli. It was used two types of static images--geometrical figures and images of hand gestures. We judge about formation of auditory-visual association by behavioural disturbance (reaction time, percentage of wrong reactions) after changes in experimental protocol viz. partial substitution of preceiding pairs of stimuli for the new combinations of previous images and sounds. It seems possible to get pronounced auditory-visual association when using images of hand gestures in combinnation with phoneme sounds. On the contrary, employment of images of geometrical figures instead of gestures produced only traces of auditory-visual association. We suggest that it is possible to explain the observed differencies by involvement of additional neuronal populations in auditory-visual assosiation that are preferentially responsive to biological motion.

Age-related features of the interaction of learning success and characteristics of auditory operative memory

The characteristics of the interaction between learning success and measures of auditory operative memory were studied by psychoacoustic testing of 42 medical workers aged 20-65 years trained to work in areas new to them (information science). Three age groups were identified: 20-35 years, 36-50 years, and 51-65 years. The acoustic test consisted of a single presentation via headphones of 12 sequential target words from information science with subsequent presentation of 12 target and 12 masking words in random order. The subjects' task was to recognize the target words. Stepwise linear regression analysis identified a relationship between the efficiency with which the new material was learned and measures of auditory operative memory, whose role in learning success increased with age. Since subjects older than 35 years showed a reduction in remembering efficiency, it was suggested that age-related changes in the characteristics of auditory operative memory are one of the major reasons for degradation of the ability to learn new material.

[Age-related changes in the relationship between learning progress and auditory working memory characteristics]

In order to explore the relationship between learning progress and working memory characteristics, the psychoacoustic testing of 42 persons (20-65 years old) of medical staff taught a novel science (informatics) was carried out. The subjects were divided into three age groups: 20-35, 36-50, and 51-65-year-olds. Acoustical test consisted of a set of 12 target words (professional informatics terms) presented through headphones and subsequent presentation of a random succession of 12 target and 12 masking words (all of them being professional informatics terms). Listeners had to recognize the target words. The stepwise linear regression analysis revealed a link between the progress in acquisition of the new material and characteristics of acoustical working memory, whose role in learning progress increased with age. Because the memory efficiency reduction was found in subjects older than 35 years, it was supposed that age-related changes in characteristics of the acoustical working memory were responsible for the decline in ability to learn novel material.

Ontogenetic Features of the Psychophysiological Mechanisms of Perception of the Emotional Component of Speech in Musically Gifted Children

The cerebral mechanisms underlying musical-artistic ability were addressed by studying psychophysical measures of the perception of emotional information contained in speech in musically gifted children. Studies involved 46 schoolchildren and 48 young musicians, in three age groups: 7-10, 11-13, and 14-17 years. A test sentence was presented with three emotional intonations (joy, anger, and unemotional) via headphones; subjects' responses identifying the type of emotion were recorded. Dispersion analysis revealed age and gender characteristics in the mechanisms of recognition of emotions: thus, boy musicians led their classmates in the development of these mechanisms by 4-6 years, while girl musicians led by 1-3 years. In girls, musical training facilitated increases in the role of the left hemisphere in processing the emotional intonation of speech, while in boys, the initially marked dominance of the left hemisphere was not retained during further training.

[Ontogenetic features of psychophysiological mechanisms of perception of speech emotional component in musically gifted children]

Cerebral mechanisms of musical abilities were explored in musically gifted children. For this purpose, psychophysiological characteristics of perception of emotional speech information were experimentally studied in samples of gifted and ordinary children. Forty six schoolchildren and forty eight musicians of three age groups (7-10, 11-13 and 14-17 years old) participated in the study. In experimental session, a test sentence was presented to a subject through headphones with two emotional intonations (joy and anger) and without emotional expression. A subject had to recognize the type of emotion. His/her answers were recorded. The analysis of variance revealed age- and gender-related features of emotional recognition: boys musicians led the schoolchildren of the same age by 4-6 years in the development of mechanisms of emotional recognition, whereas girls musicians were 1-3 years ahead. Musical education in girls induced the shift of predominant activities for emotional perception in the left hemisphere; in boys, on the contrary, initial distinct dominance of the left hemisphere was not retained in the process of further education.

[Ontogeny-specific interaction of psychophysiological mechanisms of emotional perception and educational achievement in students]

In order to explore the process of adaptation of children to school environment psychophysiological characteristics of perception of emotional speech information and school progress were experimentally studied. Forty-six schoolchildren of three age groups (7-10, 11-13, and 14-17 years old) participated in the study. In experimental session, a test sentence was presented to a subject through headphones with two emotional intonations (joy and anger) and without emotional expression. A subject had to recognize the type of emotion. His/her answers were recorded. School progress was determined by year grades in Russian, foreign language, and mathematics. Analysis of variance and linear regression analysis showed that ontogenetic features of a correlation between psychophysiological mechanisms of emotion recognition and school progress were gender- and subject-dependent. This correlation was stronger in 7-13-year-old children than in senior children. This age boundary was passed by the girls earlier than by the boys.

[Lateralization characteristics in the perception of speech in noise by children of different age groups]

The comparative investigation in ontogenesis of the noise immunity of child sensorial perception of two kinds of bioacoustical information (the emotional one being more evolutionary old and the semantic one being evolutionary younger) has shown that the perception effectiveness of these kinds of information depends on the noise level, the age of a child and the kind of information. The perception of semantic information is not provided with the reliable mechanisms of signal identification from noise even to the age of 16 while such mechanisms for perception of emotional information are formed in ontogenesis by the age of 14 and they are associated with the activity of the right hemisphere.

[The formation of interhemispheric asymmetry in human ontogeny during the perception of emotions in normal speech and in stuttering]

Age peculiarities of functional brain asymmetry in perception of emotional information of speech have been revealed. It was shown that the age of 4-7 years is most important for formation of this asymmetry in emotional perception. It is in this age that functional reorganization of perception in stuttering children is observed. These data indicate that correction of emotional activity in stutterers should be made at early periods of their life.

[THe age-related characteristics of interhemispheric asymmetry during the perception of verbal information by stuttering children]

Age peculiarities of functional brain asymmetry in perception of emotional information of the speech have been revealed. It was shown that the age of 4-7 years is the most important period in ontogenesis for the age dynamics of functional brain asymmetry in perception of emotions. It is in this particular age that functional reorganization of perception in stuttering children is observed. The revealed disturbances in functional brain asymmetry indicate that correction of emotional activity in stutterers should be made during early periods of ontogenesis.

[Ontogenetic aspects of individual characteristics of functional brain asymmetry in the perception of emotions]

Studies have been made on individual variations in perception of speech emotional information by 7-16-year children. Significant differences between subjects from various age groups were found concerning the correct recognition of emotions, the degree of brain asymmetry and domination type. The exactness of emotional recognition increases with age, while the degree of asymmetry becomes lower, the right hemisphere domination becoming more stable in processing of speech emotional information. With age, individual type of asymmetry turns to the specific one, reflecting asymmetry formation during evolution.

[Sex differences of functional lateralization in the perception of verbal and emotional information in ontogeny]

Experimental data show certain differences between men and women in perception of verbal and emotional information. They are revealed in the ability of correct perception of definite kind of information, in the degree of brain functional asymmetry in perception of the given information, in prevalence of domination type. The character of sex differences in functional asymmetry changes little with the age; quantitative correlations of the coefficient of asymmetry diminish with the age.

[Age-related characteristics of human perception of emotions in speech and in singing]

Monoaural presentation (in sequence to the left and right ears) of speech and vocal-musical phrases with different emotional content (joy, grief, anger, fear, indifference) has been made to children ageing between 7 and 16 years. These passages were performed by professional actors or singers. Absolute differences in the probability of correct identification of different emotions were obtained. They are maximal for fear and anger, being minimal for joy. Left ear preference to perception of emotions both in speech and in singing is already formed in 7-8 years old children.

[Interhemispheric brain asymmetry in speech perception by persons of different age groups and the "effect of directional attention"]

Using dichotic tests, studies have been made on the degree of functional asymmetry of the brain with respect to perception of verbal information in 3-50 years old subjects. Significant age variations were found in the volume of the percepted speech information. Interhemispheral differences in speech perception, which reveal themselves in higher perception of the right ear as compared to the left one, are more evident in children under 10 years. Significant influence of the "effect of voluntary and involuntary attention" of the subjects was noted on the degree of asymmetry of dichotic speech perception, this influence alleviating the intrinsic functional asymmetry of the brain.

Invariability of auditory perception with respect to frequency--time signal transformations in the dolphin Tursiops truncatus

The characteristic of hearing in the dolphin Tursiops truncatus were investigated by the method of motor-feeding conditioned reflexes under conditions of frequency--time signal indeterminancy with background noise. It was shown that the effectiveness of auditory detection of tone--pulse signals is invariant with respect to Doppler and shift signal transformations, while the number of waves is a characteristic parameter of the auditory system.

[Invariability of stimulus recognition by dolphins]

The echo-location characteristics were studied in dolphins with the aid of transformation of stimuli not altering the reception characteristics in analysing systems. The dolphin locator was shown to be able to single out a class of equivalent in respect to certain transformations echo-signals. The probability of the target recognition is invariable in respect to transformations of homothetic type and module transformations, i.e. the principle of invariability spreads over the work of dolphin's auditory analyser in active regimen too.

[The invariance of auditory perception with regard to frequency-temporal transformations of the signal in Tursiops truncatus dolphins]

In experiments on the porpose T. truncatus, using motor-feeding conditioned reflex technique, studies have been made on hearing under the conditions of frequency-temporal indetermination of the signal presented at noise background. It was shown that the effectiveness of auditory detection of tone-impulse signals is invariant with respect to Doppler and shift transformation of the signal, whereas the number of waves serves as a characteristic parameter of the auditory system in the porpoise.

[Efficiency of dolphin auditory perception in relation to time characteristics of the signal]

Experimental data are presented on evaluating the efficiency of auditory perception of the dolphin Tursiops truncatus of tonal signals of different duration and of the fixed energy on the background of Gauss obstacle. The dependence of percepting properties on time characteristics of the signal are stated. A comparative analysis of the efficiency of dolphin auditory system with that of the coordinated filter is carried out. Biological receiving systems are shown to be adaptive. The self-tuning linits of the dolphin auditory system at a given level of the possibility of correct detection are determined.

[Spatial analysis of tonal superthreshold signals in dolphins]

Hearing characteristics under the conditions of spacial indetermination of overthreshold tonic signal were studied on dolphins Tursiops truncatus by the method of motordigestive conditional reflexes. High efficiency of spacial analysis on the frequencies 5, 20, 80, 100 kHz was shown. The criterium of relative loss of information in the channel was used for evaluating integral index of efficiency of dolphin spacial hearing.