379 research outputs found

    Hall effect of ferro/antiferromagnetic wallpaper fermions

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    Nonsymmorphic crystals can host characteristic double surface Dirac cones with fourfold degeneracy on the Dirac points, called wallpaper fermion, protected by wallpaper group symmetry. We clarify the charge and spin Hall effect of wallpaper fermions in the presence of the (anti)ferromagnetism.Based on a four-sublattice model, we construct the effective Hamiltonian of wallpaper fermions coupled with the ferromagnetic or antiferromagnetic moment.Both ferromagnetic and antiferromagnetic moments induce an energy gap for the wallpaper fermions, leading to quantized (spin) Hall conductivity. The ferromagnetic wallpaper fermion induces the Hall conductivity quantized into e2/he^2/h, which is twice that for a single Dirac fermion on the surface of topological insulators. On the other hand, the spin Hall conductivity decays and reaches to be a finite value as the antiferromagnetic coupling increases. We also show that the results above are valid for a general model of wallpaper fermions from symmetry consideration.Comment: 9 pages, 22 figure

    Examination of High-Torque Sandwich-Type Spherical Ultrasonic Motor Using with High-Power Multimode Annular Vibrating Stator

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    Spherical ultrasonic motors (SUSMs) that can operate with multiple degrees of freedom (MDOF) using only a single stator have high holding torque and high torque at low speed, which makes reduction gearing unnecessary. The simple structure of MDOF-SUSMs makes them useful as compact actuators, but their development is still insufficient for applications such as joints of humanoid robots and other systems that require MDOF and high torque. To increase the torque of a sandwich-type MDOF-SUSM, we have not only made the vibrating stator and spherical rotor larger but also improved the structure using three design concepts: (1) increasing the strength of all three vibration modes using multilayered piezoelectric actuators (MPAs) embedded in the stator, (2) enhancing the rigidity of the friction driving portion of the stator for transmitting more vibration force to the friction-driven rotor surface, and (3) making the support mechanism more stable. An MDOF-SUSM prototype was tested, and the maximum torques of rotation around the X(Y)-axis and Z-axis were measured as 1.48 N?m and 2.05 N?m, respectively. Moreover, the values for torque per unit weight of the stator were obtained as 0.87 N?m/kg for the X(Y)-axis and 1.20 N?m/kg for the Z-axis. These are larger than values reported for any other sandwich-type MDOF-SUSM of which we are aware. Hence, the new design concepts were shown to be effective for increasing torque. In addition, we measured the transient response and calculated the load characteristics of rotation around the rotor’s three orthogonal axes

    Is increased fat content of hindmilk due to the size or the number of milk fat globules?

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    <p>Abstract</p> <p>Background</p> <p>It is known that the fat content of breast milk is higher in hindmilk than in foremilk. However, it has not been determined if this increased fat content results from an increase in the number of milk fat globules (MFGs), an increase in the size of MFGs, or both. This study aims to determine which factor plays the most important role.</p> <p>Methods</p> <p>Thirteen breastfeeding mothers were enrolled in the study and we obtained 52 samples from 26 breasts before (foremilk) and after (hindmilk) a breastfeeding session. The fat content was evaluated by creamatocrit (CrCt) values. MFG size was measured with the laser light scattering method. We compared CrCt values and MFG size between foremilk and hindmilk.</p> <p>Results</p> <p>Although the CrCt values were higher in the hindmilk (8.6 ± 3.6%) than in the foremilk (3.7 ± 1.7%), the MFG size did not change (4.2 ± 1.0 μm and 4.6 ± 2.1 μm, foremilk and hindmilk, respectively). There was no relationship between the changes in CrCt versus MFG size from foremilk to hindmilk.</p> <p>Conclusion</p> <p>The results indicate that the increase in fat content results mainly from the increased number of MFGs, which may be released into the milk flow as the mammary lobe becomes progressively emptied.</p

    Psychological Stress and Coping in Recently Discharged Postsurgical Cancer Patients

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    Objective: Cancer patients and survivors need to cope with various stressful situations and problems even after treatment. In this study, we sought to investigate psychological stress and coping in recently discharged postsurgical cancer patients.Methods: A mail-in questionnaire survey about stress response, perceived illness-related demands, and coping strategies and styles was administered to postsurgical Japanese cancer patients. The questionnaires were returned a week after the patients\u27 discharge from the hospital. Descriptive and nonparametric statistical analyses were used.Results: Forty-two patients completed the questionnaire; their average age was 58.1 years, and 61.9% were female. The stress response scale-18 (SRS-18) score was lower than that reported among the general population. The proportion of patients who were concentrating coping on social support or positive reappraisal was high. The scores for problem- and emotion-focused coping were nearly identical. SRS-18 scores were weakly correlated with those for emotion-focused coping (r = 0.38, P = 0.014). The demographic data were not significantly associated with any of the stress or coping variables. However, SRS-18 scores for patients who had adjuvant therapy and physical, functional disorders were significantly higher than those for patients who did not (P = 0.004 and P = 0.008, respectively).Conclusions: Most of the patients had a low-stress response and used appropriate coping strategies. However, the findings suggest that attention must be paid to stress-coping in patients who have a physical, functional disorder as well as in those receiving adjuvant therapy

    Description of three new bat-associated species of hard ticks (Acari, Ixodidae) from Japan

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    In Eurasia, the geographically most widespread ixodid tick species of the bat families Rhinolophidae Gray, Vespertilionidae Gray, and Miniopteridae Dobson were considered to belong to four species, Ixodes vespertilionis Koch, I. collaris Hornok, I. ariadnae Hornok, and I. simplex Neumann. Previous data attest that bat-associated tick species from Eastern Asia show remarkable genetic difference from the above four tick species, but in the absence of detailed morphological comparison these were regarded as conspecific. In this study we compensate for this lack of data on three bat-associated tick species, reporting their morphological comparison, as well as molecular and phylogenetic relationships. According to the results we describe the females of three tick species new to science, i.e., I. nipponrhinolophi Hornok &amp;amp; Takano, sp. nov., I. fuliginosus Hornok &amp;amp; Takano, sp. nov., and I. fujitai Hornok &amp;amp; Takano, sp. nov. In case of all three new tick species the cytochrome c oxidase subunit (coxI) gene showed remarkably high sequence differences from the species that they previously were thought to belong to, well exceeding the average limit delineating ixodid tick species. This, as well as observed morphological differences fully justify their taxonomical status as new species

    Osmosensitivity of Transient Receptor Potential Vanilloid 1 Is Synergistically Enhanced by Distinct Activating Stimuli Such as Temperature and Protons

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    In animals, body-fluid osmolality is continuously monitored to keep it within a narrow range around a set point (∼300 mOsm/kg). Transient receptor potential vanilloid 1 (TRPV1), a cation channel, has been implicated in body-fluid homeostasis in vivo based on studies with the TRPV1-knockout mouse. However, the response of TRPV1 to hypertonic stimuli has not been demonstrated with heterologous expression systems so far, despite intense efforts by several groups. Thus, the molecular entity of the hypertonic sensor in vivo still remains controversial. Here we found that the full-length form of TRPV1 is sensitive to an osmotic increase exclusively at around body temperature using HEK293 cells stably expressing rat TRPV1. At an ambient temperature of 24°C, a slight increase in the intracellular calcium concentration ([Ca2+]i) was rarely observed in response to hypertonic stimuli. However, the magnitude of the osmosensitive response markedly increased with temperature, peaking at around 36°C. Importantly, the response at 36°C showed a robust increase over a hypertonic range, but a small decrease over a hypotonic range. A TRPV1 antagonist, capsazepine, and a nonspecific TRP channel inhibitor, ruthenium red, completely blocked the increase in [Ca2+]i. These results endorse the view that the full-length form of TRPV1 is able to function as a sensor of hypertonic stimuli in vivo. Furthermore, we found that protons and capsaicin likewise synergistically potentiated the response of TRPV1 to hypertonic stimuli. Of note, HgCl2, which blocks aquaporins and inhibits cell-volume changes, significantly reduced the osmosensitive response. Our findings thus indicate that TRPV1 integrates multiple different types of activating stimuli, and that TRPV1 is sensitive to hypertonic stimuli under physiologically relevant conditions

    Co-expression network of neural-differentiation genes shows specific pattern in schizophrenia

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    Background: Schizophrenia is a neurodevelopmental disorder with genetic and environmental factors contributing to its pathogenesis, although the mechanism is unknown due to the difficulties in accessing diseased tissue during human neurodevelopment. The aim of this study was to find neuronal differentiation genes disrupted in schizophrenia and to evaluate those genes in post-mortem brain tissues from schizophrenia cases and controls. Methods: We analyzed differentially expressed genes (DEG), copy number variation (CNV) and differential methylation in human induced pluripotent stem cells (hiPSC) derived from fibroblasts from one control and one schizophrenia patient and further differentiated into neuron (NPC). Expression of the DEG were analyzed with microarrays of post-mortem brain tissue (frontal cortex) cohort of 29 schizophrenia cases and 30 controls. A Weighted Gene Co-expression Network Analysis (WGCNA) using the DEG was used to detect clusters of co-expressed genes that werenon-conserved between adult cases and controls brain samples. Results: We identified methylation alterations potentially involved with neuronal differentiation in schizophrenia, which displayed an over-representation of genes related to chromatin remodeling complex (adjP = 0.04). We found 228 DEG associated with neuronal differentiation. These genes were involved with metabolic processes, signal transduction, nervous system development, regulation of neurogenesis and neuronal differentiation. Between adult brain samples from cases and controls there were 233 DEG, with only four genes overlapping with the 228 DEG, probably because we compared single cell to tissue bulks and more importantly, the cells were at different stages of development. The comparison of the co-expressed network of the 228 genes in adult brain samples between cases and controls revealed a less conserved module enriched for genes associated with oxidative stress and negative regulation of cell differentiation. Conclusion: This study supports the relevance of using cellular approaches to dissect molecular aspects of neurogenesis with impact in the schizophrenic brain. We showed that, although generated by different approaches, both sets of DEG associated to schizophrenia were involved with neocortical development. The results add to the hypothesis that critical metabolic changes may be occurring during early neurodevelopment influencing faulty development of the brain and potentially contributing to further vulnerability to the illness.We thank the patients, doctors and nurses involved with sample collection and the Stanley Medical Research Institute. This research was supported by either Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq #17/2008) and Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ). MM (CNPq 304429/2014-7), ACT (FAPESP 2014/00041-1), LL (CAPES 10682/13-9) HV (CAPES) and BP (PPSUS 137270) were supported by their fellowshipsinfo:eu-repo/semantics/publishedVersio

    Repair, regenerative and supportive therapies of the annulus fibrosus: achievements and challenges

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    Lumbar discectomy is a very effective therapy for neurological decompression in patients suffering from sciatica due to hernia nuclei pulposus. However, high recurrence rates and persisting post-operative low back pain in these patients require serious attention. In the past decade, tissue engineering strategies have been developed mainly targeted to the regeneration of the nucleus pulposus (NP) of the intervertebral disc. Accompanying techniques that deal with the damaged annulus fibrous are now increasingly recognised as mandatory in order to prevent re-herniation to increase the potential of NP repair and to confine NP replacement therapies. In the current review, the requirements, achievements and challenges in this quickly emerging field of research are discussed
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