TRITIUM CONCENTRATION IN MONTHLY PRECIPITATION NEAR THE FUSION TEST FACILITY IN JAPAN BEFORE AND AFTER THE DEUTERIUM PLASMA EXPERIMENT.

In Japan, the deuterium plasma experiment using the Large Helical Device was started at the National Institute for Fusion Science (NIFS) in March 2017 to investigate high-temperature plasma physics and hydrogen isotope effects in research leading towards the realisation of fusion energy. The deuterium plasma experiment produces small amount of tritium by fusion reactions. To understand any impacts by the experiment to the surrounding environment, monthly precipitation samples have been collected at the NIFS site since November 2013 to assess the relationship between isotope composition and chemical species in precipitation including tritium. By comparing data before and after the deuterium plasma experiment start, it was found that tritium released from the main stack of the fusion test facility had no impact on the environment surrounding NIFS.

LEVELS OF ATMOSPHERIC TRITIUM IN THE SITE OF FUSION TEST FACILITY.

In the deuterium plasma experiment using Large Helical Device at the National Institute for Fusion Science (NIFS), a small amount of tritium is produced by the D-D fusion reaction. Then, a part of produced tritium is discharged into the environment via a stack. Thus, the atmospheric tritium in the site of NIFS has been monitored before starting the deuterium plasma experiment. The atmospheric tritium concentrations at NIFS were indicated to be background levels in Japan. To investigate the impact of tritium discharged from the stack, the correlation between the atmospheric tritium concentration and the tritium concentration observed in the stack was evaluated, and no significant correlation was found. In addition, the atmospheric tritium concentration at NIFS ranged within the background levels in Japan. Therefore, the impact of discharged tritium from the stack would be negligible in the environment at NIFS.

Temporal and Spatial Variation of Radon Concentrations in Environmental Water from Okinawa Island, Southwestern Part of Japan.

In this study, to get a better understanding in characterizing groundwater and ensure its effective management, the radon concentrations in water samples were measured through Ryukyu limestone in southern Okinawa Island, Japan. Water samples were collected from a limestone cave (Gyokusendo cave, dropping water) and two springs (Ukinju and Komesu, spring water), and the radon concentrations were measured by liquid scintillation counters. The radon concentrations in the samples from the Gyokusendo cave, and Ukinju and Komesu springs were 10 ± 1.3 Bq L-1, 3.2 ± 1.0 Bq L-1, and 3.1 ± 1.1 Bq L-1, respectively. The radon concentrations showed a gradually increasing trend from summer to autumn and decreased during winter. The variation of radon concentrations in the dripping water sample from the Gyokusendo cave showed a lagged response to precipitation changes by approximately 2-3 months. The estimated radon concentrations in the dripping water sample were calculated with the measured radon concentrations from the dripping water obtained during the study period. Based on our results, groundwater in the Gyokusendo cave system was estimated to percolate through the Ryukyu limestone in 7-10 days, and the residence time of groundwater in the soil above Gyokusendo cave was estimated to be approximately 50-80 days. This work makes a valuable contribution to the understanding of groundwater processes in limestone aquifers, which is essential for ensuring groundwater sustainability.

Isotope Composition and Chemical Species of Monthly Precipitation Collected at the Site of a Fusion Test Facility in Japan.

The deuterium plasma experiment was started using the Large Helical Device (LHD) at the National Institute for Fusion Science (NIFS) in March 2017 to investigate high-temperature plasma physics and the hydrogen isotope effects towards the realization of fusion energy. In order to clarify any experimental impacts on precipitation, precipitation has been collected at the NIFS site since November 2013 as a means to assess the relationship between isotope composition and chemical species in precipitation containing tritium. The tritium concentration ranged from 0.10 to 0.61 Bq L-1 and was high in spring and low in summer. The stable isotope composition and the chemical species were unchanged before and after the deuterium plasma experiment. Additionally, the tritium concentration after starting the deuterium plasma experiment was within three sigma of the average tritium concentration before the deuterium plasma experiment. These results suggested that there was no impact by tritium on the environment surrounding the fusion test facility.

The Effects of Housing Density on Social Interactions and Their Correlations with Serotonin in Rodents and Primates.

Population density has been suggested to affect social interactions of individuals, but the underlying neural mechanisms remain unclear. In contrast, neurotransmission of monoamines such as serotonin (5-HT) and dopamine (DA) has been demonstrated to play important roles in social behaviors. Here, we investigated whether housing density affected social interactions of rodents and non-human primates housed in groups, and its correlations with monoamines. Japanese macaques exhibited higher plasma 5-HT, but not DA, concentrations than rhesus macaques. Similarly, C57BL/6 mice exhibited higher plasma and brain tissue 5-HT concentrations than DBA2 mice. Under crowding, C57BL/6 mice and Japanese macaques exhibited more prominent social avoidance with mates than DBA2 mice and rhesus macaques, respectively. Although DBA2 mice and rhesus macaques in crowding exhibited elevated plasma stress hormones, such stress hormone elevations associated with crowding were absent in C57BL/6 mice and Japanese macaques. Administration of parachlorophenylalanine, which inhibits 5-HT synthesis, increased social interactions and stress hormones in C57BL/6 mice under crowding. These results suggest that, animals with hyperserotonemia may exhibit social avoidance as an adaptive behavioral strategy to mitigate stress associated with crowding environments, which may also be relevant to psychiatric disorder such as autism spectrum disorder.

Dopamine-dependent social information processing in non-human primates.

RATIONALE: Dopamine (DA) is a neurotransmitter whose roles have been suggested in various aspects of brain functions. Recent studies in rodents have reported its roles in social function. However, how DA is involved in social information processing in primates has largely remained unclear. OBJECTIVES: We investigated prefrontal cortical (PFC) activities associated with social vs. nonsocial visual stimulus processing. METHODS: Near-infrared spectroscopy (NIRS) was applied to Japanese macaques, along with pharmacological manipulations of DA transmission, while they were gazing at social and nonsocial visual stimuli. RESULTS: Oxygenated (oxy-Hb) and deoxygenated (deoxy-Hb) hemoglobin changes as well as functional connectivity based on such Hb changes within the PFC network which were distinct between social and nonsocial stimuli were observed. Administration of both D1 and D2 receptor antagonists affected the Hb changes associated with social stimuli, whereas D1, but not D2, receptor antagonist affected the Hb changes associated with nonsocial stimuli. CONCLUSIONS: These results suggest that mesocortical DA transmission in the PFC plays significant roles in social information processing, which involves both D1 and D2 receptor activation, in nonhuman primates. However, D1 and D2 receptor signaling in the PFC mediates different aspects of social vs. nonsocial information processing.

Dopamine-dependent visual attention preference to social stimuli in nonhuman primates.

RATIONALE: Dopamine (DA) plays a central role in reward processing. Accumulating evidence suggests that social interaction and social stimuli have rewarding properties that activate the DA reward circuits. However, few studies have attempted to investigate how DA is involved in the processing of social stimuli. OBJECTIVES: In this study, we investigated the effects of pharmacological manipulations of DA D1 and D2 receptors on social vs. nonsocial visual attention preference in macaques. METHODS: Japanese macaques were subjected to behavioral tests in which visual attention toward social (monkey faces with and without affective expressions) and nonsocial stimuli was examined, with D1 and D2 antagonist administration. RESULTS: The macaques exhibited significantly longer durations of gazing toward the images with social cues than did those with nonsocial cues. Both D1 and D2 antagonist administration decreased duration of gazing toward the social images with and without affective valences. In addition, although D1 antagonist administration increased the duration of gazing toward the nonsocial images, D2 antagonism had no effect. CONCLUSIONS: These results suggest that both D1 and D2 receptors may have roles in the processing of social signals but through separate mechanisms.

The Roles of Dopamine D2 Receptor in the Social Hierarchy of Rodents and Primates.

Dopamine (DA) plays significant roles in regulation of social behavior. In social groups of humans and other animals, social hierarchy exists, which is determined by several behavioral characteristics such as aggression and impulsivity as well as social affiliations. In this study, we investigated the effects of pharmacological blockade of DA D2 receptor on social hierarchy of Japanese macaque and mouse social groups. We found acute administration of the D2 antagonist, sulpiride, in socially housed Japanese macaques attenuated social dominance when the drug was given to high social class macaques. A similar attenuation of social dominance was observed in high social class mice with D2 antagonist administration. In contrast, D2 antagonist administration in low social class macaque resulted in more stable social hierarchy of the group, whereas such effect was not observed in mouse social group. These results suggest that D2 receptor signaling may play important roles in establishment and maintenance of social hierarchy in social groups of several species of animals.

Prefrontal cortical activity associated with visual stimulus categorization in non-human primates measured with near-infrared spectroscopy.

In biomedical research of brain dysfunction in psychiatric disorders, utilization of animal models is essential. However, translation of findings in animal models into the realm of human clinical conditions requires reliable biomarkers that are assessed with the methods mutually employed in animal models and human patients. Near-infrared spectroscopy (NIRS) is a functional neuroimaging technique that has now been widely utilized in human basic and clinical research. However, its application to animal models has been barely conducted. In this study, we developed the method to measure neural activity in the cortex of Japanese macaques using NIRS, and examined cortical responses to presentation of a set of visual stimuli that were categorized into four different groups (flower, monkey, snake, food). Prefrontal cortical (PFC) oxy- and deoxy-hemoglobin changes were found to reliably distinguish the categories of these visual stimuli. The results suggest that cortical activity measurement with NIRS in primates can be a valuable model for identifying biomarkers associated with psychiatric disorders.

The Roles of Dopamine D1 Receptor on the Social Hierarchy of Rodents and Nonhuman Primates.

Background: Although dopamine has been suggested to play a role in mediating social behaviors of individual animals, it is not clear whether such dopamine signaling contributes to attributes of social groups such as social hierarchy. Methods: In this study, the effects of the pharmacological manipulation of dopamine D1 receptor function on the social hierarchy and behavior of group-housed mice and macaques were investigated using a battery of behavioral tests. Results: D1 receptor blockade facilitated social dominance in mice at the middle, but not high or low, social rank in the groups without altering social preference among mates. In contrast, the administration of a D1 receptor antagonist in a macaque did not affect social dominance of the drug-treated animal; however, relative social dominance relationships between the drug-treated and nontreated subjects were altered indirectly through alterations of social affiliative relationships within the social group. Conclusions: These results suggest that dopamine D1 receptor signaling may be involved in social hierarchy and social relationships within a group, which may differ between rodents and primates.

Immature male gibbons produce female-specific songs.

Gibbons are apes that are well known to produce characteristic species-specific loud calls, referred to as "songs." Of particular interest is the sex specificity of the "great calls" heard in gibbon songs. However, little is known about the development of such calls. While great calls are given by female gibbons of various ages, they have never been recorded from males. Here, we report two observations of immature male gibbons from two different species, wild Hylobates agilis and captive H. lar, which spontaneously sang female-specific great calls. Based on the video clips, we conclude that immature males also have the potential to produce great calls. Our observations led us to propose a new hypothesis for the development of sexual differentiation in the songs of gibbons, and its implications for the general issue of sex-specific behavior in primates.

Is attentional prioritisation of infant faces unique in humans?: Comparative demonstrations by modified dot-probe task in monkeys.

Humans innately perceive infantile features as cute. The ethologist Konrad Lorenz proposed that the infantile features of mammals and birds, known as the baby schema (kindchenschema), motivate caretaking behaviour. As biologically relevant stimuli, newborns are likely to be processed specially in terms of visual attention, perception, and cognition. Recent demonstrations on human participants have shown visual attentional prioritisation to newborn faces (i.e., newborn faces capture visual attention). Although characteristics equivalent to those found in the faces of human infants are found in nonhuman primates, attentional capture by newborn faces has not been tested in nonhuman primates. We examined whether conspecific newborn faces captured the visual attention of two Japanese monkeys using a target-detection task based on dot-probe tasks commonly used in human visual attention studies. Although visual cues enhanced target detection in subject monkeys, our results, unlike those for humans, showed no evidence of an attentional prioritisation for newborn faces by monkeys. Our demonstrations showed the validity of dot-probe task for visual attention studies in monkeys and propose a novel approach to bridge the gap between human and nonhuman primate social cognition research. This suggests that attentional capture by newborn faces is not common to macaques, but it is unclear if nursing experiences influence their perception and recognition of infantile appraisal stimuli. We need additional comparative studies to reveal the evolutionary origins of baby-schema perception and recognition.

Influence of sound specificity and familiarity on Japanese macaques' (Macaca fuscata) auditory laterality.

Despite attempts to generalise the left hemisphere-speech association of humans to animal communication, the debate remains open. More studies on primates are needed to explore the potential effects of sound specificity and familiarity. Familiar and non-familiar nonhuman primate contact calls, bird calls and non-biological sounds were broadcast to Japanese macaques. Macaques turned their heads preferentially towards the left (right hemisphere) when hearing conspecific or familiar primates supporting hemispheric specialisation. Our results support the role of experience in brain organisation and the importance of social factors to understand laterality evolution.

Discovery of anti-varicella zoster virus activity of polyether antibiotic CP-44161.

In search for new anti-varicella zoster virus (VZV) compounds with new mechanism of action, we applied a DNA hybridization assay (dot blot method) for screening. Using this method, we screened microbial products and found the polyether compound CP-44161 from the culture broth of an actinomycete strain. CP-44161 was previously reported as an anticoccidal agent, but there has been no claim of its antiviral activities. CP-44161 showed strong anti-VZV activity against pOka strain by plaque reduction assay. Moreover, CP-44161 showed lower cytotoxicity than other antiviral polyethers, such as monensin and nigericin. Its better safety margin and strong anti-VZV properties make it a good candidate for a new anti-VZV agent.

Anti-herpes virus activity of polyether antibiotic CP-44161 in vivo.

In the previous study, we discovered a polyether antibiotic CP-44161, which was reported earlier as an anticoccidal agent, as an anti-varicella zoster virus compound. In this study, we demonstrated that CP-44161 had a very strong and broad anti-herpes virus activities against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in vitro. To determine the antiviral activity of CP-44161 in vivo, we examined its effect on the cutaneous HSV-2 infection model in Balb/c mice. CP-44161 showed inhibitory effect on lesion development as well as acyclovir (ACV) when the treatment was started from day 3. Meanwhile, in case the start of treatment was delayed until day 4, when ACV was no longer effective, the effectiveness of CP-44161 still remained. In this model, CP-44161 also showed inhibitory effect on the proliferation of HSV-2 DNA in dorsal root ganglia. This is the first article to report that polyether antibiotics can be effective on viral infection in vivo.

Role of biological-motion information in recognition of facial expressions by young children.

Data on the development of the perception of facial biological motion during preschool years are disproportionately scarce. We investigated the ability of preschoolers to recognise happy, angry, and surprised expressions, and eye-closing facial movements on the basis of facial biological motion. Children aged 4 years (n = 18) and 5-6 years (n = 19), and adults (n = 17) participated in a matching task, in which they were required to match the point-light displays of facial expressions to prototypic schematic images of facial expressions and facial movement. The results revealed that the ability to recognise facial expressions from biological motion emerges as early as the age of 4 years. This ability was evident for happy expressions at the age of 4 years; 5-6-year-olds reliably recognised surprised as well as happy expressions. The theoretical significances of these findings are discussed.

Deterioration of planning ability with age in Japanese monkeys (Macaca fuscata).

To investigate the ability of aged monkeys to plan and the effect of aging on this ability, performance in a food retrieval task was assessed in aged and younger Japanese monkeys (Macaca fuscata). In this task, the monkeys had to retrieve food items by selecting from a set of 9 holes, each of which contained 1 food item. Results showed that task performance declined significantly with age. All monkeys showed, to a greater or lesser extent, some consistent patterns in their sequence of selecting holes for retrieving the food item. An analysis of these selection patterns indicated that the younger monkeys showed more consistent sequences in selection than the aged monkeys. Furthermore, success in the task performance correlated strongly with higher consistency in the sequence of selecting holes. The authors simulated performance for this task by monkeys without any strategies or plans. The results suggest that the empirical data were far more systematic than the simulated data. Thus, the authors conclude that Japanese monkeys have the ability to plan and that this ability to plan deteriorates with age.

Cloning, expression, purification, crystallization and preliminary X-ray analysis of human liver glyceraldehyde-3-phosphate dehydrogenase.

Human liver glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was purified and crystallized using PEG 3350 as a precipitant. However, the crystals were extremely fragile towards osmotic shock. A 1% change in PEG 3350 content causes destruction of the crystals. After many trials for freezing the crystals, X-ray diffraction data from a native crystal were collected at 2.8 A resolution using as a cryoprotectant a mixture consisting of paraffin oil and Paratone-N in a 3:1 ratio and a cryoloop covered with Formver film. Crystals belong to space group P2(1), with unit-cell parameters a = 63.23, b = 97.84, c = 84.23 A, beta = 104.1 degrees. Molecular replacement with a starting model consisting of a homology model based on the low-resolution structure of human skeletal muscle GAPDH, which has 90% identical residues with the liver protein, led to a solution. Most of the current model was assigned properly in the electron-density map, but the map corresponding to some important regions containing the phosphate-binding loop was ambiguous. It is planned to crystallize human liver GAPDH in the presence of phosphate ions and/or some kind of inhibitor in order to fix the flexible region.

Algogen-specific pain processing in mouse spinal cord: differential involvement of voltage-dependent Ca(2+) channels in synaptic transmission.

1. The effects of intrathecal (i.t.) administration of N-, P/Q- or L-type voltage-dependent Ca(2+)-channel blockers were tested in two pain models involving bradykinin (BK)- and alpha,beta-methylene ATP (alpha,beta meATP)-induced activation of primary afferent neurons in mice. 2. The nociceptive response (amount of time spent licking and biting the hindpaw) induced by intraplantar injection of BK (500 pmol mouse(-1)) was significantly attenuated by both omega-conotoxin GVIA (N-type blocker) and calciseptine (L-type) but not by omega-agatoxin IVA (P/Q-type). 3. The nociceptive response induced in a similar way by alpha,beta meATP (100 nmol) was significantly inhibited by both the above N- and P/Q-type Ca(2+)-channel blockers but not by the L-type blocker. 4. The nociceptive responses elicited by BK and alpha,beta meATP were dose-dependently inhibited by a tachykinin-NK1-receptor antagonist (L-703,606) and an N-methyl-D-aspartate (NMDA)-receptor antagonist (D-AP5), respectively. 5. Intrathecal administration of substance P (SP) (1.8 nmol) or NMDA (350 pmol) elicited algesic responses, such as licking, biting and scratching of the hindquarters. The SP-induced algesic behaviour was significantly inhibited by the L-type blocker but not by the N-type. The NMDA-induced response was not affected by either the N- or the P/Q-type blocker. 6. These findings suggest that BK and ATP most likely excite different types of sensory neurons in the periphery and that within the spinal cord the former stimulates peptidergic transmission regulated by presynaptic N- and postsynaptic L-type Ca(2+) channels, while the latter stimulates glutamatergic transmission regulated by presynaptic N- and P/Q-type channels.