Self-assembling, anthracene-based supramolecular nanofibers can enable excitons to migrate hundreds of nanometers, according to a new experimental finding by researchers at Science Tokyo. Coupling these nanofibers with a plasmonic nanohole gold substrate further doubles exciton diffusivity. By mitigating the limited diffusivity of singlet excitons in organic semiconductors, this offers a new strategy for improving optoelectronic technologies.

Drawing inspiration from the dynamic architecture of living systems, researchers from Institute of Science Tokyo and Kyoto University have harnessed two chemically fueled biomolecular nanomachines, DNA polymerase and kinesin, to synthesize and actively assemble complex, hierarchical DNA networks. The work opens a route toward programmable, lifelike synthetic materials built from the nanoscale up.

When a pattern drawn only in black and white is rotated, people sometimes perceive colors that are not actually present. This phenomenon is known as “subjective color” and has been studied for approximately 200 years as one of the remarkable mysteries of vision. Among such phenomena, Benham’s top is a well-known example in which colors are perceived simply by spinning a black-and-white disk. A research group led by Associate Professor Eiji Watanabe of NIBB used an artificial neural network trained through predictive learning to investigate the mechanism underlying this subjective color phenomenon. The research group presented a black-and-white Benham’s top to an AI model that had been trained to predict “what kind of image will come next” after viewing natural videos. Although the input images contained no color information at all, faint colors appeared in the images predicted by the AI. Furthermore, the artificially generated colors were found to change depending on the colors of moving objects contained in the videos used to train the AI. Analyses using natural videos, 3D computer graphics, and simple two-dimensional videos of moving red, green, and blue squares suggested that learning the association between motion and color may be one factor that enables colors to emerge from black-and-white stimuli. This study suggests that subjective color may not be a phenomenon completed solely within the retina, but may also be related to the brain’s function of predicting future visual input based on past experience. By using AI, the study provides a new clue to the classical mystery of why colors are perceived from a black-and-white spinning top. These findings were published in Scientific Reports.

Developmental prosopagnosia is a neurodevelopmental condition in which individuals have lifelong difficulties in face processing, including identifying and remembering faces. In a recent study, researchers comprehensively evaluated the 20-item prosopagnosia index, which is a commonly used questionnaire for screening developmental prosopagnosia. Using established and advanced statistical methods, the researchers confirmed the questionnaire's reliability and validity and revealed opportunities to improve individual questions, paving the way for better and effective screening of the condition.

How similar are “joy” and “surprise”? Conversely, how far apart are “joy” and “sadness”?

We naturally organize words that express emotions—such as “happy,” “afraid,” and “angry”—according to similarities and differences in their meanings. However, investigating this entire structure using human participants alone is not easy, because the number of comparisons rises rapidly as more emotion terms are included.

Specially Appointed Assistant Professor Ke Han and Associate Professor Eiji Watanabe of the Laboratory of Neurophysiology, National Institute for Basic Biology (NIBB) investigated the semantic organization of emotion terms by asking GPT-4 to arrange those terms in a spatial layout and comparing the results with human judgments.

The results showed that prompting GPT-4 with a task in ordinary language reproduced a structure closely resembling the arrangements made by human participants. Moreover, when the vocabulary was expanded to 99 terms, a structure related to emotional intensity, or arousal, emerged that had been difficult to detect using only a small number of emotion terms. These research findings were published in Scientific Reports.

Kyoto, Japan -- Where they could once hop and amble freely, urbanization is diminishing the habitats of amphibians. Yet, small-scale water bodies managed by people -- such as those found in the gardens of Japan's temples, shrines, and schools -- remain within urban areas, providing oases for our moist neighbors.

Though the ponds and streams found in the gardens of Kyoto's temples and shrines are maintained as cultural landscapes, their function as habitats for urban amphibians has not been fully explored. This inspired a Kyoto University-led research team to examine the habitat capacity of these gardens. The team saw their potential as biocultural aquatic landscapes, where culture and biodiversity intersect.

The researchers utilized both visual and DNA analyses in their search for local amphibians, as some species are difficult to observe directly while others are hard to detect at certain times of the year. They conducted visual surveys at 80 water bodies located within 31 temples, shrines, and associated facilities in Kyoto's Higashiyama area, which helped them identify adults, eggs, and larvae, while an auditory element helped them identify calls. The team also performed environmental DNA analyses at 43 of these water bodies, in addition to recording the type of water body, water source and flow, distance from forest, riparian structure, and the presence or absence of carp in order to analyze the relationship between species and environmental conditions.