Publications by authors named "Ayaka Ikeda"

[AuPt(C6)] (C6 = 1-hexanethiolate) is twice as active as commercial Pt nanoparticles in promoting the electrocatalytic hydrogen evolution reaction (HER), thereby attracting attention as new HER catalysts with well-controlled geometric structures. In this study, we succeeded in synthesizing two new Au-Pt alloy nanoclusters, namely, [AuPt(TBBT)(TDT)] (TBBT = 4--butylbenzenethiolate; TDT = thiodithiolate) and [AuPt(TBBT)(PDT)] (PDT = 1,3-propanedithiolate), by exchanging all the ligands of [AuPt(PET)] (PET = 2-phenylethanethiolate) with mono- or dithiolates. Although [AuPt(TBBT)(TDT)] was synthesized serendipitously, a similar cluster, [AuPt(TBBT)(PDT)], was subsequently obtained by selecting the appropriate reaction conditions and optimal combination of thiolate and dithiolate ligands.

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Article Synopsis
  • Recent research has focused on moral self-licensing, where people act unethically after behaving ethically, but it hasn't fully explored how children perceive individuals who exhibit this behavior as they grow.
  • The study involved children aged 5-6, 7-8, and university students to assess changes in moral evaluation, social preferences, and predictions of moral behavior towards those displaying moral licensing versus purely immoral behavior.
  • Results showed that while 5-6-year-olds couldn't differentiate between moral and immoral licensing characters, older children (7-8 years) and adults viewed moral licensing as more acceptable than outright immoral acts, indicating a developmental shift in how moral traits are assessed from around age
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Although the developmental process of linguistic register-the appropriate manner of speech as determined by the listener and social situation-has been gradually clarified in typically developing (TD) children, research on the mechanism and developmental process of register acquisition in atypically developing children are insufficient. This study compared the developmental process of understanding linguistic register among TD children, autistic children, and those with Williams syndrome (WS), and examined the contributions of social cognition and motivation to the acquisition of linguistic register. Two experiments were designed to assess the recognition of which linguistic register to use when communicating with different listeners and of the listener's feelings according to the speakers' use of register.

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Purpose: With the current study, we aimed to reveal the similarities and differences in sensory profiles between Williams syndrome (WS) and autism spectrum disorder.

Methods: Using the sensory profile questionnaire completed by the caregivers, we analyzed the WS (n = 60, 3.4-19.

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Although research has shed light on the development of emotion comprehension in typically developing children, little is known about emotion comprehension in children who are developing atypically. Thus, this study examined the developmental trajectory of emotion understanding in non-clinical (NC) children and children with autism spectrum disorder (ASD) and Williams syndrome (WS) using a Test of Emotion Comprehension. In the test, we measured children's understanding of (I) recognition of emotions based on facial expressions, (II) external causes of emotions, (III) desire-based emotions, (IV) belief-based emotions, (V) the influence of a reminder on a present emotional state, (VI) regulating an experienced emotion, (VII) hiding an emotional state, (VIII) mixed emotions, and (IX) moral emotions.

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Metal nanoclusters composed of noble elements such as gold (Au) or silver (Ag) are regarded as superatoms. In recent years, the understanding of the materials composed of superatoms, which are often called superatomic molecules, has gradually progressed for Au-based materials. However, there is still little information on Ag-based superatomic molecules.

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This study examined the similarities/differences between the social phenotypes of Williams syndrome (WS) and autism spectrum disorder (ASD). As cultural norms may affect symptom evaluation, this study administered the Social Responsiveness Scale-2 to Japanese individuals with WS (n = 78, 4.4-44.

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To use atomically precise metal nanoclusters (NCs) in various application fields, it is essential to establish size-selective synthesis methods for the metal NCs. Studies on thiolate (SR)-protected gold NCs (Au (SR) NCs) revealed that the atomically precise Au (SR) NC, which has a different chemical composition from the precursor, can be synthesized size-selectively by inducing transformation in the framework structure of the metal NCs by a ligand-exchange reaction. In this study, we selected the reaction of [Au(SCHPh)] (SCHPh = 2-phenylethanethiolate) with 4--butylbenzenethiol ( BuPhSH) as a model ligand-exchange reaction and attempted to obtain new metal NCs by changing the amount of thiol, the central atom of the precursor NCs, or the reaction time from previous studies.

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Understanding how we see the world is different from how other people see it is a crucial part of social cognition and is known as visual perspective-taking. Although previous studies have demonstrated that 14-month-old infants have the capacity to compute the visual perspectives of others, it remains unknown whether infants under 12 months also have this ability. In this study, we modified a conventional gaze-following experimental setting in which one toy was placed in front of a model and was hidden by a barrier (Blocked Line of Sight Condition), and another toy was placed without a barrier (Clear Line of Sight Condition).

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Icosahedral noble-metal 13-atom nanoclusters (NCs) can form connected structures, which can be regarded as superatomic molecules, by vertex sharing. However, there have been very few reports on the superatomic molecules formed using silver (Ag) as the base element. In this study, we synthesized [AgPd(PPh)Cl] (Pd = palladium, PPh = triphenylphosphine, Cl = chloride), in which two icosahedral 13-atom NCs are connected, and elucidated its geometric and electronic structures to clarify what type of superatomic molecules can be synthesized.

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'Motionese' can be defined as an exaggerated and repetitive action. It induces preference and learning in infants. However, which action component of motionese promotes infants' preference and learning remains largely unknown.

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We are expected to behave appropriately to suit social situations. One form of behavioral control is the selection of a linguistic register that is appropriate to the listener. Register selection errors can sometimes be interpreted as rude behavior and result in having a bad influence on the relationship with the listener and the evaluation by other people.

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Recent studies in developmental psychology have revealed the developmental origins of cooperation. Although such studies regard cooperation as a pro-social behavior, studies on adults have found a negative aspect: cooperation sometimes promotes unethical behavior. Adults also exhibit altruistic cheating, even though their cheating might not actually benefit them.

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Linguistic register reflects changes in speech that depend on the situation, especially the status of listeners and listener-speaker relationships. Following the sociolinguistic rules of register is essential in establishing and maintaining social interactions. Recent research suggests that children over 3 years of age can understand appropriate register-listener relationships as well as the fact that people change register depending on their listeners.

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This study provides the first physiological evidence of humans' ability to empathize with robot pain and highlights the difference in empathy for humans and robots. We performed electroencephalography in 15 healthy adults who observed either human- or robot-hand pictures in painful or non-painful situations such as a finger cut by a knife. We found that the descending phase of the P3 component was larger for the painful stimuli than the non-painful stimuli, regardless of whether the hand belonged to a human or robot.

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We have previously demonstrated super-induced expression of the Grin2c gene encoding the N-methyl-D-aspartate receptor 2C subunit during the process of liver enlargement induced by phenobarbital, clofibrate, piperonyl butoxide, or lead nitrate. In the present study, hepatic Grin2c gene expression levels were assessed by real-time RT-PCR in male F344 rats fed for 3 days, 4 weeks, and 13 weeks a diet containing either β-naphthoflavone (BNF) (5,000 ppm), indole-3-carbinol (I3C) (2,000 ppm), or acetaminophen (AA) (12,500 ppm until the first 14 days; 10,000 ppm from 15 days on), each of which is capable of inducing hepatocellular hypertrophy. Especially, either the 4-week or the 13-week treatment with each chemical, except for BNF, resulted in a drastic increase in the expression level of the Grin2c gene.

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Increased expression of thioredoxin-interacting protein (TXNIP) has recently been proved to be a crucial event for irremediable endoplasmic reticulum (ER) stress resulting in the programmed cell death (apoptosis) of pancreatic β-cells. The present study demonstrated that treatment with 1-10 μg/ml tunicamycin, a potent revulsant of ER stress, drastically induced TXNIP expression accompanied by the generation of cleaved caspase-3 as an indicator of apoptosis in SK-N-SH human neuroblastoma cells. This result substantiated that TXNIP is also involved in neurodegeneration triggered by ER stress.

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Serum total cholesterol amounts in the stroke-prone hypertensive rat (SHRSP) strain are lower than in the normotensive control strain, Wistar-Kyoto (WKY) rat. To understand the strain difference, constitutive gene expression levels of hepatic cholesterol biosynthetic enzymes in male 8-week-old SHRSP and WKY rats were comparatively examined by DNA microarray and real-time reverse transcription-polymerase chain reaction (RT-PCR) analyses. Of 22 cholesterol biosynthetic enzyme genes, expression levels of 8 genes, Pmvk, Idi1, Fdps, Fdft1, Sqle, Lss, Sc4mol, and Hsd17b7, in SHRSP were less than 50% those of the WKY rats; especially, the expression level of Sqle gene, encoding squalene epoxidase, a rate-limiting enzyme in cholesterol biosynthesis pathway, was about 20%.

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We previously demonstrated the super-induced expression of the Grin2c gene encoding the N-methyl-D-aspartate receptor 2C subunit during the development of liver enlargement with hepatocellular hypertrophy induced by phenobarbital, clofibrate, or piperonyl butoxide. In the present study, we assessed whether or not Grin2c gene expression was induced during the development of chemically induced liver enlargement with hyperplasia. Male Sprague-Dawley (SD) rats, stroke-prone spontaneously hypertensive rats (SHRSPs), and SHRSP's normotensive control, Wistar-Kyoto (WKY) rats, were administered lead nitrate (LN) (0.

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Nobiletin, a polymethoxylated flavonoid that is highly contained in the peels of citrus fruits, exerts a wide variety of beneficial effects, including anti-proliferative effects in cancer cells, repressive effects in hyperlipidemia and hyperglycemia, and ameliorative effects in dementia at in vitro and in vivo levels. In the present study, to further understand the mechanisms of these actions of nobiletin, the nobiletin-mediated alterations of gene expression in three organ-derived cell lines - 3Y1 rat fibroblasts, HuH-7 human hepatocarcinoma cells, and SK-N-SH human neuroblastoma cells - were first examined with DNA microarrays. In all three cell lines, treatments with nobiletin (100 μM) for 24 h resulted in more than 200% increases in the expression levels of five genes, including the endoplasmic reticulum stress-responsive genes Ddit3, Trib3, and Asns, and in less than 50% decreases in the expression levels of seven genes, including the cell cycle-regulating genes Ccna2, Ccne2, and E2f8 and the oxidative stress-promoting gene Txnip.

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To identify gene expression that can be closely involved in chemical-induced hepatocellular hypertrophy, the hepatic gene expression profile was assessed by cDNA microarray analysis in male F344 rats fed for 3 days, 4 weeks, and 13 weeks a diet containing a hepatocellular hypertrophy inducer, either phenobarbital (500 ppm), clofibrate (2,500 ppm), or piperonyl butoxide (20,000 ppm). The results showed that, in all treatment groups, the increased expressional rate of the Grin2c gene, which encodes the N-methyl-D-aspartate receptor 2C subunit (NR2C), was the highest among those of all the genes tested, as compared with the corresponding gene expression in rats fed a normal diet. Moreover, real-time RT-PCR analysis showed that the expression levels of the Grin2c gene in rats fed with each chemical clearly increased in a chemical treatment period-dependent fashion, and that the increased rate was closely correlated with the grade of hypertrophy of hepatocytes rather than with the increased rate in liver weight.

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