213 research outputs found

    Introducing the Amphibious Mudskipper Goby as a Unique Model to Evaluate Neuro/Endocrine Regulation of Behaviors Mediated by Buccal Sensation and Corticosteroids

    Get PDF
    Some fish have acquired the ability to breathe air, but these fish can no longer flush their gills effectively when out of water. Hence, they have developed characteristic means for defense against external stressors, including thirst (osmolarity/ions) and toxicity. Amphibious fish, extant air-breathing fish emerged from water, may serve as models to examine physiological responses to these stressors. Some of these fish, including mudskipper gobies such asPeriophthalmodon schlosseri,Boleophthalmus boddartiand ourPeriophthalmus modestus, display distinct adaptational behaviors to these factors compared with fully aquatic fish. In this review, we introduce the mudskipper goby as a unique model to study the behaviors and the neuro/endocrine mechanisms of behavioral responses to the stressors. Our studies have shown that a local sensation of thirst in the buccal cavity-this being induced by dipsogenic hormones-motivates these fish to move to water through a forebrain response. The corticosteroid system, which is responsive to various stressors, also stimulates migration, possibly via the receptors in the brain. We suggest that such fish are an important model to deepen insights into the stress-related neuro/endocrine-behavioral effects

    Theoretical Analysis of Rigid-Body Vibration in Swing Compressors

    Get PDF
    This study aims to theoretically analyze the rigid-body vibration in swing compressors. Currently, low noise and vibration (NV) are qualities recognized as a desired value for an air conditioner by end users. Because the compressor is one of the main sources of NV in an air conditioner, low NV compressors are needed. Designing a low NV compressor requires the understanding of the physical phenomena occurring in a compressor that contribute to NV. In this study, we theoretically analyzed rigid-body vibration, which has been one of the main phenomena causing NV in a swing compressor. Main factors causing rigid-body vibration in the swing compressor were classified into three types of excitation forces. By formulating them in a Fourier series representation, the primary and secondary components in the frequency domain were calculated for each excitation force without any numerical calculation method, including FFT. Furthermore, by multiplying the mass and inertial tensor of the compressor to this, we calculated both the amplitude and phase of the rigid-body vibration generated by each excitation force. We then confirmed that the calculated vibration was consistent with the experimental results. The contribution of each excitation force to the radial and tangential vibrations of typical swing compressors was theoretically analyzed. The results of the analysis clearly indicated that vibration was effectively reduced by not only simply reducing the magnitudes of the excitation forces but also by balancing the excitation forces

    On the Change of Reversible Susceptibility of Ferromagnetic Substances Due to Tension

    Get PDF
    According to the internal stress theory on ferromagnetic substances given by Kersten and Doring, the authors have calculated the reversible susceptibility as a function of magnetization under various applied tensions. Theoretical reversible susceptibility thus obtained is constant at early stage of magnetization and decreases rapidly just before the magnetic saturation. But, if the magnitude of internal stress is larger than that applied, it has a maximum before sudden decrease, which occurs near magnetic saturation. These theoretical results explain experimental data qualitatively, but some quantitative differences are found between these

    Footedness for scratching itchy eyes in rodents

    Get PDF
    The neural bases of itchy eye transmission remain unclear compared with those involved in body itch. Here, we show in rodents that the gastrin-releasing peptide receptor (GRPR) of the trigeminal sensory system is involved in the transmission of itchy eyes. Interestingly, we further demonstrate a difference in scratching behaviour between the left and right hindfeet in rodents; histamine instillation into the conjunctival sac of both eyes revealed right-foot biased laterality in the scratching movements. Unilateral histamine instillation specifically induced neural activation in the ipsilateral sensory pathway, with no significant difference between the activations following left- and right-eye instillations. Thus, the behavioural laterality is presumably due to right-foot preference in rodents. Genetically modified rats with specific depletion of Grpr-expressing neurons in the trigeminal sensory nucleus caudalis of the medulla oblongata exhibited fewer and shorter histamine-induced scratching movements than controls and eliminated the footedness. These results taken together indicate that the Grp-expressing neurons are required for the transmission of itch sensation from the eyes, but that foot preference is generated centrally. These findings could open up a new field of research on the mechanisms of the laterality in vertebrates and also offer new potential therapeutic approaches to refractory pruritic eye disorders

    The gastrin-releasing peptide/bombesin system revisited by a reverse-evolutionary study considering Xenopus

    Get PDF
    Bombesin is a putative antibacterial peptide isolated from the skin of the frog, Bombina bombina. Two related (bombesin-like) peptides, gastrin-releasing peptide (GRP) and neuromedin B (NMB) have been found in mammals. The history of GRP/bombesin discovery has caused little attention to be paid to the evolutionary relationship of GRP/bombesin and their receptors in vertebrates. We have classified the peptides and their receptors from the phylogenetic viewpoint using a newly established genetic database and bioinformatics. Here we show, by using a clawed frog (Xenopus tropicalis), that GRP is not a mammalian counterpart of bombesin and also that, whereas the GRP system is widely conserved among vertebrates, the NMB/bombesin system has diversified in certain lineages, in particular in frog species. To understand the derivation of GRP system in the ancestor of mammals, we have focused on the GRP system in Xenopus. Gene expression analyses combined with immunohistochemistry and Western blotting experiments demonstrated that GRP peptides and their receptors are distributed in the brain and stomach of Xenopus. We conclude that GRP peptides and their receptors have evolved from ancestral (GRP-like peptide) homologues to play multiple roles in both the gut and the brain as one of the 'gut-brain peptide' systems

    Evaluation of Tree Barks and their Hybrid Materials with Hydrophilic Polymers as Adsorbents for Heavy Metal Ions

    Get PDF
    The radioactive pollutions in environment caused by the accident of atomic power plants in Fukushima, Japan, is still serious and rapid measures to the severe problem is required. It is well known that various biomass have adsorption ability for toxic metal ions from aqueous media. We have evaluated the adsorption ability of the bark of Cryptomeria japonica and Chamaecyparis obtusa, and their hybrid materials with hydrophilic polymers, for cesium, strontium, and other heavy metal ions. As the results, these materials are useful as adsorbents for a water and soil purification system

    Neural Mechanism of Altered Limb Perceptions Caused by Temporal Sensorimotor Incongruence

    Get PDF
    Previous studies have demonstrated that patients with strokes or pathological pain suffer distorted limb ownership and an inability to perceive their affected limbs as a part of their bodies. These disturbances are apparent in experiments showing time delays between motor commands and visual feedback. The experimental paradigm manipulating temporal delay is considered possible to clarify, in detail, the degree of altered limb perception, peculiarity and movement disorders that are caused by temporal sensorimotor incongruence. However, the neural mechanisms of these body perceptions, peculiarity and motor control remain unknown. In this experiment, we used exact low-resolution brain electromagnetic tomography (eLORETA) with independent component analysis (ICA) to clarify the neural mechanisms of altered limb perceptions caused by temporal sensorimotor incongruence. Seventeen healthy participants were recruited, and temporal sensorimotor incongruence was systematically evoked using a visual feedback delay system. Participants periodically extended their right wrists while viewing video images of their hands that were delayed by 0, 150, 250, 350 and 600 ms. To investigate neural mechanisms, altered limb perceptions were then rated using the 7-point Likert scale and brain activities were concomitantly examined with electroencephalographic (EEG) analyses using eLORETA-ICA. These experiments revealed that peculiarities are caused prior to perceptions of limb loss and heaviness. Moreover, we show that supplementary motor and parietal association areas are involved in changes of peculiarity, limb loss, heaviness and movement accuracy due to temporal sensorimotor incongruence. We suggest that abnormalities in these areas contribute to neural mechanisms that modify altered limb perceptions and movement accuracy

    The Amphibious Mudskipper: A Unique Model Bridging the Gap of Central Actions of Osmoregulatory Hormones Between Terrestrial and Aquatic Vertebrates

    Get PDF
    Body fluid regulation, or osmoregulation, continues to be a major topic in comparative physiology, and teleost fishes have been the subject of intensive research. Great progress has been made in understanding the osmoregulatory mechanisms including drinking behavior in teleosts and mammals. Mudskipper gobies can bridge the gap from aquatic to terrestrial habitats by their amphibious behavior, but the studies are yet emerging. In this review, we introduce this unique teleost as a model to study osmoregulatory behaviors, particularly amphibious behaviors regulated by the central action of hormones. Regarding drinking behavior of mammals, a thirst sensation is aroused by angiotensin II (Ang II) through direct actions on the forebrain circumventricular structures, which predominantly motivates them to search for water and take it into the mouth for drinking. By contrast, aquatic teleosts can drink water that is constantly present in their mouth only by reflex swallowing, and Ang II induces swallowing by acting on the hindbrain circumventricular organ without inducing thirst. In mudskippers, however, through the loss of buccal water by swallowing, which appears to induce buccal drying on land, Ang II motivates these fishes to move to water for drinking. Thus, mudskippers revealed a unique thirst regulation by sensory detection in the buccal cavity. In addition, the neurohypophysial hormones, isotocin (IT) and vasotocin (VT), promote migration to water via IT receptors in mudskippers. VT is also dipsogenic and the neurons in the forebrain may mediate their thirst. VT regulates social behaviors as well as osmoregulation. The VT-induced migration appears to be a submissive response of subordinate mudskippers to escape from competitive and dehydrating land. Together with implications of VT in aggression, mudskippers may bridge the multiple functions of neurohypophysial hormones. Interestingly, cortisol, an important hormone for seawater adaptation and stress response in teleosts, also stimulates the migration toward water, mediated possibly via the mineralocorticoid receptor. The corticosteroid system that is responsive to external stressors can accelerate emergence of migration to alternative habitats. In this review, we suggest this unique teleost as an important model to deepen insights into the behavioral roles of these hormones in relation to osmoregulation

    日本の大学における英語アカデミックライティング教育の可能性と課題

    Get PDF
    Today, whether English's dominance as a global lingua franca benefits higher education, more and more universities around the world have made efforts to integrate English academic writing education into their institutional policies and strategies. This trend has been observed particularly against the background where, with the increased internationalization of higher education, the imperative for universities globally to focus on maintaining or improving their international reputation and rankings has grown significantly. Indeed, such prestige tends to be assessed largely in terms of publications in English. With this in mind, we are concerned with how higher education institutions address these efforts toward promoting English academic writing in a specific non-English L1 context, namely Japan. English academic writing in university contexts where English is an additional language exists where the fields of language education, higher education administration, research methodology, and cultural socialization converge. Therefore, this volume brings together scholarship that aims to examine the different ways in which academic writing education shapes and is shaped by students, faculty and other stakeholders in Japanese universities. This volume’s eight chapters, by authors with diverse backgrounds, ranging from administrators to researchers, and from humanities and social sciences to medical studies, explore the opportunities and challenges of English academic writing education in Japanese universities by looking at related topics, including writing centers, faculty members, genre-specific education, and technology development. Together, the discussions in the individual chapters can contribute profoundly to theory, policy, and practice in the domains of curriculum, research, and administration in university contexts.Introduction… Norifumi Miyokawa 1 Part I: A writing center in Japan: Hiroshima University Chapter One: Development of the Hiroshima University Writing Center -From an administrative perspective-… Hiroko Araki & Norifumi Miyokawa 3 Chapter Two: Perceptions of academic writing support -A needs analysis of the Hiroshima University Writing Center-… Roehl Sybing & Norifumi Miyokawa 17 Part II: Faculty development for academic writing Chapter Three: Potential roles of writing centers for writing related Faculty Development… Machi Sato & Shinichi Cho 31 Chapter Four: Academic writing support for faculty members -Writing Groups and Writing Retreats-… Adina Staicov 45 Part III: Genre-specific education: Cases in the medical field Chapter Five: How to write the Introduction of biomedical research articles -Move analysis of the first and last sentences-… Takeshi Kawamoto & Tatsuya Ishii 57 Chapter Six: Error analysis of overt lexicogrammatical errors in the prepublication English-language manuscripts of Japanese biomedical researchers -With implications for the teaching of writing for biomedical research –… Flaminia Miyamasu 67 Part IV: Theoretical and practical approaches to academic writing Chapter Seven: Language socialization and writing centers… Akiko Katayama 81 Chapter Eight: Socialization into integrity -Using plagiarism software to teach L2 writing-… Gavin Furukawa 95 Acknowledgements… Norifumi Miyokawa 10
    corecore