Animals in Search of Stimulation and Information: A Review of over 10 years of our Research on Spontaneous Exploration in Rats as a Response to Novelty in Low-Stress Paradigm

This article comprehensively reviews our studies that analyzed novelty-related behaviors in rats. We developed and utilized techniques and equipment during these studies to ensure our findings' high ecological validity. We allowed rats to explore a testing apparatus freely, and after a long habituation phase consisting of multiple trials, we introduced non-emotionally arousing changes. The research shows that rats demonstrate enhanced abilities in processing and responding to heightened environmental complexity, as evidenced across various studies. Conversely, when environmental complexity diminishes, rats exhibit reduced exploratory behaviors and decreased cognitive effort despite the adaptive importance of such behaviors. Of particular interest is the observation that rats exhibit greater sensitivity to emerging opportunities in contrast to their limited responsiveness to diminishing ones, unveiling a novel facet of the animal mind that warrants further investigation. The influence of individual experiences before testing sessions on the processing of sensory input in terms of complexity is also determined. Our studies highlight the noteworthy impact of environmental unpredictability versus stability on cognitive development, affecting behaviors like food neophobia and exploration. Furthermore, the social environment during development holds wide-ranging implications for individual characteristics, necessitating continued research and refinement of our understanding in this domain. Moreover, the studies recognize strain and species differences in novelty-related behavior, primarily characterized by quantitative variations that do not overshadow the animals' coping strategies in response to environmental changes. Additionally, curiosity is portrayed as an active approach to seeking and processing environmental affordances, with exploratory behaviors fulfilling this cognitive and motivational need. The authors underscore the significance of ecological validity in test methodologies, particularly in designing environments that authentically invite and encourage pertinent behavioral responses. In summary, this research enhances our insight into rat cognition, underscores the role of curiosity, and underscores the imperative of ecological validity in experimental design, ultimately advancing our comprehension of animal behavior and cognition

Switching from electron to hole transport in solution-processed organic blend field-effect transistors

Organic electronics became an attractive alternative for practical applications in complementary logic circuits due to the unique features of organic semiconductors such as solution processability and ease of large-area manufacturing. Bulk heterojunctions (BHJ), consisting of a blend of two organic semiconductors of different electronic affinities, allow fabrication of a broad range of devices such as light-emitting transistors, light-emitting diodes, photovoltaics, photodetectors, ambipolar transistors and sensors. In this work, the charge carrier transport of BHJ films in field-effect transistors is switched from electron to hole domination upon processing and post-treatment. Low molecular weight n-type N,N′-bis(n-octyl)-(1,7&1,6)-dicyanoperylene-3,4:9,10-bis(dicarboximide) (PDI8-CN2) was blended with p-type poly[2,5-bis(3-tetradecylthiophene-2-yl)thieno[3,2-b]thiophene] (PBTTT-C14) and deposited by spin-coating to form BHJ films. Systematic investigation of the role of rotation speed, solution temperature, and thermal annealing on thin film morphology was performed using atomic force microscopy, scanning electron microscopy, and grazing incidence wide-angle X-ray scattering. It has been determined that upon thermal annealing the BHJ morphology is modified from small interconnected PDI8-CN2 crystals uniformly distributed in the polymer fraction to large planar PDI8-CN2 crystal domains on top of the blend film, leading to the switch from electron to hole transport in field-effect transistors

The development of juvenile-typical patterns of play fighting in juvenile rats does not depend on peer-peer play experience in the peri-weaning period

Open access article. Creative Commons Attribution 4.0 International License (CC BY 4.0) appliesPlay fighting in rats involves attack and defense of the nape. To protect the nape, rats use a variety of defensive tactics, with different strains having specific preferences. Targeting of the nape is established before weaning and defense matures over the course of the week preceding and the week proceeding weaning. Thus, it is possible that experience from engaging in immature forms of play is needed to consolidate the nape as the playful target and for the development of the juvenile-typical pattern of defense. Two experiments were conducted to evaluate this possibility. For the first experiment, male rats were reared over the week post-weaning in either pairs or alone, and their play tested with unfamiliar partners when juveniles (31-34 days). For the second experiment, during the week preceding weaning, male and female rats were placed into one of three conditions: (1) with the mother and no peers, (2) with same-sex siblings but no mother, or (3) with both the mother and same-sex siblings. The subjects were tested in same-sex, samecondition pairs when juveniles (31-34 days). Rats from all conditions, in both experiments, attacked the nape during play fighting and developed the same juvenile-typical patterns of playful defense. This suggests that the experience of peer-peer play in the peri-weaning period is not necessary for the development of the attack and defense components of juvenile-typical play.Ye

Pinning in the play fighting of rats: a comparative perspective with methodological recommendations

Open access article. Creative Commons Attribution 4.0 International LIcense (CC BY 4.0) appliesDuring play fighting, rats attack and defend the nape of the neck and during the course of this competitive interaction, they may adopt a configuration in which one animal stands over its supine partner (i.e., pin). Because the pin configuration is typically frequent and relatively easy to identify, it has been widely used as a marker to detect the effects of experimental treatments. In the present study, the frequency of pinning during standardized, 10-min trials in three strains of rats, Long Evans hooded (LE), Sprague-Dawley (SD) and wild (WWCPS), was compared. LE and SD had higher rates than WWCPS rats (#/min: 6.5, 5.5, 1.5, respectively). When adjusted for strain differences in the frequency of attacks, SD as well as WWCPS rats had lower rates of pinning compared to LE rats. Both SD and WWCPS rats were less likely to use tactics of defense that promote pinning. Moreover, while the majority of the pins achieved in LE rats arose from the defender actively rolling over onto its back, the majority of pins in WWCPS rats arose because one partner pushed the other onto its back. SD rats were intermediate in this regard. Finally, once they do adopt the pin configuration, SD rats are less likely to remain supine than LE and WWCPS rats. That is, both SD and WWCPS rats have significantly fewer pins than LE rats, but a different combination of factors account for this. These data highlight the need to use a battery of measures for ascertaining the effects of experimental manipulations on play. Some suggested guidelines are provided.Ye

Developing Composite Insulating Cross-Arms for 400 kV Lattice Towers

\u3cp\u3ePolymorphism of organic semiconducting materials exerts critical effects on their physical properties such as optical absorption, emission and electrical conductivity, and provides an excellent platform for investigating structure–property relations. It is, however, challenging to efficiently tune the polymorphism of conjugated polymers in aggregated, semi-crystalline phases due to their conformational freedom and anisotropic nature. Here, two distinctly different semi-crystalline polymorphs (β\u3csub\u3e1\u3c/sub\u3e and β\u3csub\u3e2\u3c/sub\u3e) of a low-bandgap diketopyrrolopyrrole polymer are formed through controlling the solvent quality, as evidenced by spectroscopic, structural, thermal and charge transport studies. Compared to β\u3csub\u3e1\u3c/sub\u3e, the β\u3csub\u3e2\u3c/sub\u3e polymorph exhibits a lower optical band gap, an enhanced photoluminescence, a reduced π-stacking distance, a higher hole mobility in field-effect transistors and improved photocurrent generation in polymer solar cells. The β\u3csub\u3e1\u3c/sub\u3e and β\u3csub\u3e2\u3c/sub\u3e polymorphs provide insights into the control of polymer self-organization for plastic electronics and hold potential for developing programmable ink formulations for next-generation electronic devices.\u3c/p\u3

Characterization of Electronic Materials

Electronic materials are of great interest due to their potential to be applied in a broad range of important electronic devices including transistors, sensors, solar cells and others [...