294 research outputs found

    Fluoxetine-induced dematuration of hippocampal neurons and adult cortical neurogenesis in the common marmoset

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    The selective serotonin reuptake inhibitor fluoxetine (FLX) is widely used to treat depression and anxiety disorders. Chronic FLX treatment reportedly induces cellular responses in the brain, including increased adult hippocampal and cortical neurogenesis and reversal of neuron maturation in the hippocampus, amygdala, and cortex. However, because most previous studies have used rodent models, it remains unclear whether these FLX-induced changes occur in the primate brain. To evaluate the effects of FLX in the primate brain, we used immunohistological methods to assess neurogenesis and the expression of neuronal maturity markers following chronic FLX treatment (3 mg/kg/day for 4 weeks) in adult marmosets (n = 3 per group). We found increased expression of doublecortin and calretinin, markers of immature neurons, in the hippocampal dentate gyrus of FLX-treated marmosets. Further, FLX treatment reduced parvalbumin expression and the number of neurons with perineuronal nets, which indicate mature fast-spiking interneurons, in the hippocampus, but not in the amygdala or cerebral cortex. We also found that FLX treatment increased the generation of cortical interneurons; however, significant up-regulation of adult hippocampal neurogenesis was not observed in FLX-treated marmosets. These results suggest that dematuration of hippocampal neurons and increased cortical neurogenesis may play roles in FLX-induced effects and/or side effects. Our results are consistent with those of previous studies showing hippocampal dematuration and increased cortical neurogenesis in FLX-treated rodents. In contrast, FLX did not affect hippocampal neurogenesis or dematuration of interneurons in the amygdala and cerebral cortex

    Chiral Magnetic Effect from Q-balls

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    We apply a generic framework of linear sigma models for revealing a mechanism of the mysterious phenomenon, the chiral magnetic effect, in quark-gluon plasma. An electric current arises along a background magnetic field, which is given rise to by Q-balls (non-topological solitons) of the linear sigma model with axial anomaly. We find additional alternating current due to quark mass terms. The hadronic Q-balls, baby boson stars, may be created in heavy-ion collisions.Comment: 4 pages, 3 figures, revtex; v2: minor revisio

    Cross-linguistic lexical effects in different-script bilingual reading are modulated by task

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    Aims and objectives/purpose/research questions:Bilingual lexical processing is non-selective, which allows for activation of the non-target language, even when reading in a different script. However, while the influence of cross-script L1 lexical knowledge has been demonstrated in isolated word reading, it is unknown whether it survives in more natural reading tasks. We investigated whether crosslinguistic facilitation due to phonological similarity, semantic similarity, and L1 cognate frequency, is observed when different-script bilinguals read cognate words in their L2 in sentence context and in isolation.Design/methodology/approach:Two tasks were conducted with the same Japanese-English bilinguals and target items: A self-paced English reading task with non-highlighted target items embedded in sentence context; and an English lexical decision task. A monolingual control group also completed both tasks.Data and analysis:108 cognate items were embedded in sentence context and read by 23 Japanese-English bilinguals and 23 English monolinguals for meaning comprehension. The same items were then responded to by the same participants in lexical decision. Linear mixed-effects models were used to investigate the impact of continuous measures of L1–L2 phonological and semantic similarity, L1 cognate frequency, and L2 proficiency, while controlling for L2 lexical characteristics.Findings/conclusions:Cross-linguistic phonological and semantic similarity, as well as cognate frequency, partially determined reading times of words in both tasks but only in bilingual, not monolingual, reading. These effects were modulated by task, revealing reduced cross-linguistic facilitation in sentence reading relative to lexical decision.Originality:This is the first study to investigate different-script cognate processing in sentence context and compare it with isolated word reading.Significance/implications:Although bilinguals do not switch off their L1 during L2 reading, the type of task partially determines how cross-linguistic effects impact reading times. The degree of overlap of Japanese-English cognates is less influential in natural reading tasks compared with isolated word reading tasks

    Study on magnetic thermal seeds coated with thermal-responsive molecularly imprinted polymers

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    We conceived a novel hybrid carrier of a thermal-responsive molecularly imprinted polymer (MIP) and a magnetic thermal seed (MTS) that showed a heat-generating ability under an alternate current (AC) magnetic field. Compared to our previous publications, we modify both the MIP and MTS to improve the feasibility for the hybrid carrier, briefly we have to achieve the accurate size control and narrower size distribution of MTS, and higher molecular recognition/release ability of MIP. Firstly, uniformly sized particles which are expected to show a large heat-generating ability under an AC magnetic field were successfully prepared by controlling the core creation. Then, an MIP targeted for selective adsorption of pemetrexed (PMX), a well-known anti-cancer drug, was prepared using N-carbobenzoxy-L-glutamic acid as a pseudo template. Finally, the preliminary hybridization of the MTS and the MIP-equivalent polymer coating was examined by introducing vinyl groups as methacrylic acid using a ligand exchanging method

    Expression of progenitor cell/immature neuron markers does not present definitive evidence for adult neurogenesis

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    It is agreed upon that adult hippocampal neurogenesis (AHN) occurs in the dentate gyrus (DG) in rodents. However, the existence of AHN in humans, particularly in elderly individuals, remains to be determined. Recently, several studies reported that neural progenitor cells, neuroblasts, and immature neurons were detected in the hippocampus of elderly humans, based on the expressions of putative markers for these cells, claiming that this provides evidence of the persistence of AHN in humans. Herein, we briefly overview the phenomenon that we call “dematuration, ” in which mature neurons dedifferentiate to a pseudo-immature status and re-express the molecular markers of neural progenitor cells and immature neurons. Various conditions can easily induce dematuration, such as inflammation and hyper-excitation of neurons, and therefore, the markers for neural progenitor cells and immature neurons may not necessarily serve as markers for AHN. Thus, the aforementioned studies have not presented definitive evidence for the persistence of hippocampal neurogenesis throughout adult life in humans, and we would like to emphasize that those markers should be used cautiously when presented as evidence for AHN. Increasing AHN has been considered as a therapeutic target for Alzheimer’s disease (AD); however, given that immature neuronal markers can be re-expressed in mature adult neurons, independent of AHN, in various disease conditions including AD, strategies to increase the expression of these markers in the DG may be ineffective or may worsen the symptoms of such diseases

    High-Resolution Near-Infrared Imaging of the Powerful Radio Galaxy 3C 324 at z = 1.21 with the Subaru Telescope

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    We have obtained high-resolution K'-band images of the powerful z=1.206 radio galaxy 3C 324 with the Subaru telescope under seeing conditions of 0.3--0.4 arcsec. We clearly resolved the galaxy and directly compared it to the optical images obtained with the Hubble Space Telescope. The host galaxy of 3C 324 is revealed to be a moderately luminous elliptical galaxy with a smooth light profile. The effective radius of the galaxy, as determined by profile fitting, is 1.3+-0.1 arcsec (1.2 kpc), which is significantly smaller than the value of 2.2 arcsec, published in Best et al. (1998, MNRAS, 292, 758). The peak of the K'-band light coincides with the position of the radio core, which implies that the powerful AGN lies at the nucleus of the host galaxy. The peak also coincides with the gap in the optical knotty structures which may be a dust lane hiding the UV-optical emission of the AGN from our line of sight; it is very likely that we are seeing the obscuring structure almost edge-on. We clearly detected the `aligned component' in the K'-band image by subtracting a model elliptical galaxy from the observed image. The red R_F702W-K color of the outer region of the galaxy avoiding the aligned component indicates that the near infrared light of the host galaxy is dominated by an old stellar population.Comment: 21 pages (10 figures), accepted for publication in PAS
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