586 research outputs found

    Quantitative agreement of Dzyaloshinskii-Moriya interactions for domain-wall motion and spin-wave propagation

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    The magnetic exchange interaction is the one of the key factors governing the basic characteristics of magnetic systems. Unlike the symmetric nature of the Heisenberg exchange interaction, the interfacial Dzyaloshinskii-Moriya interaction (DMI) generates an antisymmetric exchange interaction which offers challenging opportunities in spintronics with intriguing antisymmetric phenomena. The role of the DMI, however, is still being debated, largely because distinct strengths of DMI have been measured for different magnetic objects, particularly chiral magnetic domain walls (DWs) and non-reciprocal spin waves (SWs). In this paper, we show that, after careful data analysis, both the DWs and SWs experience the same strength of DMI. This was confirmed by spin-torque efficiency measurement for the DWs, and Brillouin light scattering measurement for the SWs. This observation, therefore, indicates the unique role of the DMI on the magnetic DW and SW dynamics and also guarantees the compatibility of several DMI-measurement schemes recently proposed.Comment: 24 pages, 5 figure

    Acupuncture on GB34 activates the precentral gyrus and prefrontal cortex in Parkinson’s disease

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    Background: Acupuncture is increasingly used as an additional treatment for patients with Parkinson’s disease (PD). Methods: In this functional magnetic resonance imaging study, brain activation in response to acupuncture in a group of 12 patients with PD was compared with a group of 12 healthy participants. Acupuncture was conducted on a specific acupoint, the right GB 34 (Yanglingquan), which is a frequently used acupoint for motor function treatment in the oriental medical field. Results: Acupuncture stimulation on this acupoint activates the prefrontal cortex, precentral gyrus, and putamen in patients with PD; areas that are known to be impaired in patients with PD. Compared with healthy participants, patients with PD showed significantly higher brain activity in the prefrontal cortex and precentral gyrus, especially visible in the left hemisphere. Conclusions: The neuroimaging results of our study suggest that in future acupuncture research; the prefrontal cortex as well as the precentral gyrus should be treated for symptoms of Parkinson’s disease and that GB 34 seems to be a suitable acupoint. Moreover, acupuncture evoked different brain activations in patients with Parkinson’s disease than in healthy participants in our study, stressing the importance of conducting acupuncture studies on both healthy participants as well as patients within the same study, in order to detect acupuncture efficacy. Trial registration KCT0001122 at cris.nih.go.kr (registration date: 20140530) Electronic supplementary material The online version of this article (doi:10.1186/1472-6882-14-336) contains supplementary material, which is available to authorized users

    Bucillamine prevents cisplatin-induced ototoxicity through induction of glutathione and antioxidant genes.

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    Bucillamine is used for the treatment of rheumatoid arthritis. This study investigated the protective effects of bucillamine against cisplatin-induced damage in auditory cells, the organ of Corti from postnatal rats (P2) and adult Balb/C mice. Cisplatin increases the catalytic activity of caspase-3 and caspase-8 proteases and the production of free radicals, which were significantly suppressed by pretreatment with bucillamine. Bucillamine induces the intranuclear translocation of Nrf2 and thereby increases the expression of γ-glutamylcysteine synthetase (γ-GCS) and glutathione synthetase (GSS), which further induces intracellular antioxidant glutathione (GSH), heme oxygenase 1 (HO-1) and superoxide dismutase 2 (SOD2). However, knockdown studies of HO-1 and SOD2 suggest that the protective effect of bucillamine against cisplatin is independent of the enzymatic activity of HO-1 and SOD. Furthermore, pretreatment with bucillamine protects sensory hair cells on organ of Corti explants from cisplatin-induced cytotoxicity concomitantly with inhibition of caspase-3 activation. The auditory-brainstem-evoked response of cisplatin-injected mice shows marked increases in hearing threshold shifts, which was markedly suppressed by pretreatment with bucillamine in vivo. Taken together, bucillamine protects sensory hair cells from cisplatin through a scavenging effect on itself, as well as the induction of intracellular GSH

    Magnetic Domain-Wall Tilting due to Domain-Wall Speed Asymmetry

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    Chiral magnetic materials provide a number of challenging issues such as the highly efficient domain wall (DW) and skyrmion motions driven by electric current, as of the operation principles of emerging spintronic devices. The DWs in the chiral materials exhibit asymmetric DW speed variation under application of in plane magnetic field. Here, we show that such DW speed asymmetry causes the DW tilting during the motion along wire structure. It has been known that the DW tilting can be induced by the direct Zeeman interaction of the DW magnetization under application of in plane magnetic field. However, our experimental observations manifests that there exists another dominant process with the DW speed asymmetry caused by either the Dzyaloshinskii Moriya interaction (DMI) or the chirality dependent DW speed variation. A theoretical model based on the DW geometry reveals that the DW tilting is initiated by the DW pinning at wire edges and then, the direction of the DW tilting is determined by the DW speed asymmetry, as confirmed by a numerical simulation. The present observation reveals the decisive role of the DW pinning with the DW speed asymmetry, which determines the DW geometry and consequently, the dynamics

    Stenting of the Left Main Coronary Artery in a Patient With Takayasu's Arteritis

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    Management of Takayasu's arteritis of the left main coronary artery (LMCA) is difficult because of the possibility of restenosis. Clinically significant stenotic lesions must be considered anatomical correlation. Many studies have reported that the management of stenotic lesions of the LMCA with endoluminal stenting and balloon angioplasty and de-novo stenting is safe and effective for patients with Takayasu's arteritis. We report the case of a patient with Takayasu's arteritis of the LMCA. The patient had undergone two consecutive percutaneous coronary interventions because of recurrent restenosis of in-stent lesions, and eventually underwent coronary artery bypass graft (CABG) surgery for myocardial infarction in the same lesion. We suggested treatment with CABG because the pathophysiology of Takayasu's arteritis is different from that of atherosclerotic stenosis

    Favorable prognosis in colorectal cancer patients with co-expression of c-MYC and ß-catenin

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    This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background The purpose of our research was to determine the prognostic impact and clinicopathological feature of c-MYC and β-catenin overexpression in colorectal cancer (CRC) patients. Methods Using immunohistochemistry (IHC), we measured the c-MYC and β-catenin expression in 367 consecutive CRC patients retrospectively (cohort 1). Also, c-MYC expression was measured by mRNA in situ hybridization. Moreover, to analyze regional heterogeneity, three sites of CRC including the primary, distant and lymph node metastasis were evaluated in 176 advanced CRC patients (cohort 2). Results In cohort 1, c-MYC protein and mRNA overexpression and ß-catenin nuclear expression were found in 201 (54.8 %), 241 (65.7 %) and 221 (60.2 %) of 367 patients, respectively, each of which was associated with improved prognosis (P = 0.011, P = 0.012 and P = 0.033, respectively). Moreover, co-expression of c-MYC and ß-catenin was significantly correlated with longer survival by univariate (P = 0.012) and multivariate (P = 0.048) studies. Overexpression of c-MYC protein was associated with mRNA overexpression (ρ, 0.479; P  0.05). Conclusions Co-expression of c-MYC and ß-catenin was independently correlated with favorable prognosis in CRC patient. We concluded that the expression of c-MYC and ß-catenin might be useful predicting indicator of CRC patients prognosis
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