Regulation of the Phase Structure in the Crystallizing Curing System PCL-DGEBA.

Qualitative and quantitative aspects of the formation of various types of phase structures, sizes and compositions were considered. For the studied polycaprolactone-epoxy resin/4,4'-diaminediphenylsulfone system, a phase diagram characterized by amorphous separation with a lower critical solution temperature was constructed and its evolution was traced with increasing conversion degree of epoxy groups. A method is proposed for determining the temperature-concentration parameters that determine the type of phase structure of composite materials, based on the optical interferometry method.

Modification of Epoxy Coatings with Fluorocontaining Organosilicon Copolymers.

Preparation of hydrophobic coatings is still a challenge for researchers in various fields of science. One of the easiest ways consists of the use of special modifiers. However, usually such modifiers are poorly compatible with organic polymeric matrixes, which leads to segregation of modifiers and deterioration of coating properties.

Phase Equilibria, Diffusion and Structure in the Epoxypolycaprolactone System.

Currently, there is no quantitative approach for the phase structure of cured thermoplastic systems modified with thermoplastic predicting. To solve this problem, we carried out the first stage of the study on a model polycaprolactone-epoxy oligomer (PCL-DGEBA) system. Using differential scanning calorimetry (DSC), refractometry and optical interferometry, a phase diagram for PCL-DGEBA mixtures was constructed, and the Flory-Huggins interaction parameters of PCL-DGEBA mixtures were calculated.

Facial shape differences between rats selected for tame and aggressive behaviors.

Domestication has been consistently accompanied by a suite of traits called the domestication syndrome. These include increased docility, changes in coat coloration, prolonged juvenile behaviors, modified function of adrenal glands and reduced craniofacial dimensions. Wilkins et al recently proposed that the mechanistic factor underlying traits that encompass the domestication syndrome was altered neural crest cell (NCC) development.

Immune reactivity in rats selected for the enhancement or elimination of aggressiveness towards humans.

This study analyzes immune reactivity in two lines of rats selected for the enhancement or elimination of aggressiveness toward humans. Compared to nonaggressive line, aggressive rats showed increased blood ratio of CD4(+) and CD8(+)T lymphocytes, monocyte chemoattractant protein (MCP)-1 level both before and after immunization with sheep red blood cells (SRBC), enhanced IgM-immune response, as well as decreased level of interleukin (IL)-1α before immunization. However, antigen administration produced IL-1α increase in aggressive rats and its decrease in nonaggressive rats compared to non-immunized rats of the same lines.

Genetic influences on brain gene expression in rats selected for tameness and aggression.

Interindividual differences in many behaviors are partly due to genetic differences, but the identification of the genes and variants that influence behavior remains challenging. Here, we studied an F2 intercross of two outbred lines of rats selected for tame and aggressive behavior toward humans for >64 generations. By using a mapping approach that is able to identify genetic loci segregating within the lines, we identified four times more loci influencing tameness and aggression than by an approach that assumes fixation of causative alleles, suggesting that many causative loci were not driven to fixation by the selection.

Serotonin 5-HT1A receptor in infancy-onset aggression: comparison with genetically defined aggression in adult rats.

Antisocial aggressive behavior in adolescents represents growing clinical and social problem. Previously the implication of 5-HT1A receptor in the regulation of fear-induced aggression was shown. Here, the involvement of 5-HT1A receptor in infancy-onset genetically defined aggression was studied on Norway rats selectively bred for high level or for the lack of aggression toward man.

A comparison of brain gene expression levels in domesticated and wild animals.

Domestication has led to similar changes in morphology and behavior in several animal species, raising the question whether similarities between different domestication events also exist at the molecular level. We used mRNA sequencing to analyze genome-wide gene expression patterns in brain frontal cortex in three pairs of domesticated and wild species (dogs and wolves, pigs and wild boars, and domesticated and wild rabbits). We compared the expression differences with those between domesticated guinea pigs and a distant wild relative (Cavia aperea) as well as between two lines of rats selected for tameness or aggression towards humans.

c-Fos activation and intermale aggression in rats selected for behavior toward humans.

Tame and aggressive rat lines were created during the long-term selection of Norway rats for elimination and enhancement of aggressiveness toward humans, respectively. Our previous experiments have demonstrated that selection for the elimination of defensive aggression toward humans is associated with attenuated intraspecific intermale aggression. However, the neuronal mechanisms underlying low and high intermale aggression in the tame and aggressive rats remain unclear.

Behavioral effects of bidirectional selection for behavior towards human in virgin and lactate Norway rats.

Although numerous studies have demonstrated strong differences in behavioral, hormonal and neurobiological characteristics between male rats selected for elimination (tame) and enhancement (aggressive) of aggressiveness towards humans, few studies have examined changes in female behavior under this selection. The objective of the current work was to evaluate the effects of bidirectional selection for aggressiveness towards humans on behavioral profiles of virgin and lactating rats compared with the behavior in tame, aggressive and unselected (wild-type) females. The behavior of virgin females was studied using the light-dark box, the startle response test and the modified glove test.

Effect of domestication on aggression in gray Norway rats.

A comparative analysis of intermale aggression in the resident-intruder test was conducted with gray rats from a wild unselected population bred at the laboratory for three generations and gray rats selected for elimination (tame) and enhancement (aggressive) of aggressiveness towards human for 71-72 generations. Males from the laboratory line Wistar were used as neutral opponents. Rats from the tame line were characterized by reduced aggression manifest as longer attack latency, decreased number of attacks, upright postures, chases, kicks, and shorter total time of aggressive behavior compared to unselected males.

Conserved methylation of the glucocorticoid receptor gene exon 1(7) promoter in rats subjected to a maternal methyl-supplemented diet.

It is well known that the early life experiences affect stress responses and other physiological and behavioral traits in adulthood. Both rat and human studies have shown that early postnatal effects are associated with methylation of the hippocampal glucocorticoid receptor gene exon 1(7) (rat) and 1-F (human) promoters. Methylation of these sites is also seen following methionine administration in adult rats.

Genetic architecture of tameness in a rat model of animal domestication.

A common feature of domestic animals is tameness-i.e., they tolerate and are unafraid of human presence and handling.

Cross-fostering effects on weight, exploratory activity, acoustic startle reflex and corticosterone stress response in Norway gray rats selected for elimination and for enhancement of aggressiveness towards human.

Two rat lines, one tame, the other aggressive, differing by many behavioral features and stress reactivity were developed by long-term selection of wild gray rats for elimination and enhancement of aggressiveness towards humans. The aim of this work was to study the role of the maternal environment in the expression of these differences between the two rat lines using the cross-fostering paradigm. Fostering of tame rats of both sexes by aggressive mothers and aggressive females by tame mothers was without effect on behavior score towards humans, but the cross-fostered aggressive males had a small, yet significant, increase in aggressiveness score.

Phenotypic differences in behavior, physiology and neurochemistry between rats selected for tameness and for defensive aggression towards humans.

To better understand the biology of tameness, i.e. tolerance of human presence and handling, we analyzed two lines of wild-derived rats (Rattus norvegicus) artificially selected for tameness and defensive aggression towards humans.