423 research outputs found

    Giant geometry modulation on magnetic proximity effect observed in isomeric oxide heterostructures

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    Magnetic proximity effect (MPE) is generally considered to occur at the magnetic-nonmagnetic material interface within a short-range space domain, while the structural geometry modulation on such an interface effect has not been explored. Here, we fabricate isomeric paramagnetic metallic IrO2 with rutile and anatase structures, respectively, on a ferrimagnetic insulating CoFe2O4, and study the MPE-induced magnetism by anomalous Hall effect (AHE) measurements. The rutile phase with layered structure shows a conventional AHE and identical coercive-field with CoFe2O4, indicating a concomitant magnetic switching as a result of a strong magnetic coupling at the interface. In contrast, the anatase phase with tetrahedral structure exhibits an unconventional AHE with negative coercive-field at low temperatures. Further analyses indicate that in anatase, the contribution that strongly couples with CoFe2O4 is dramatically suppressed while a giant frustration-like response emerges. Our findings reveal that the MPE-induced spin orders can be pronouncedly modulated by structural geometry

    小特集:磁場閉じ込め核融合装置における水素原子分子輸送研究の新展開 2.要素モデルの統合が実現する壁から プラズマまでを含めた中性粒子輸送研究

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    非接触をはじめとするダイバータプラズマの諸現象を理解するため,壁での粒子リサイクリング,荷電粒子,中性粒子を扱うコードの統合を進めている.水素分子には,電子状態のほか,回転および振動の内部自由度があり,分子活性化再結合をはじめとするプラズマ中の水素分子の各種の反応速度係数は,水素分子の始状態の振動・回転量子数により,数桁にわたって変化する.また,低温のプラズマでは,プラズマ中の電子やプロトン衝突による水素分子の振動・回転励起がプラズマのエネルギー損失チャンネルとして重要と考えられる.このため,水素分子の振動・回転状態を中性粒子やプラズマの輸送と組み合わせて解く統合モデルを開発した

    Reorganization of Corticospinal Projections after Prominent Recovery of Finger Dexterity from Partial Spinal Cord Injury in Macaque Monkeys

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    We investigated morphologic changes in the corticospinal tract (CST) to understand the mechanism underlying recovery of hand function after lesion of the CST at the C4/C5 border in seven macaque monkeys. All monkeys exhibited prominent recovery of precision grip success ratio within a few months. The trajectories and terminals of CST from the contralesional (n = 4) and ipsilesional (n = 3) hand area of primary motor cortex (M1) were investigated at 5–29 months after the injury using an anterograde neural tracer, biotinylated dextran amine (BDA). Reorganization of the CST was assessed by counting the number of BDA-labeled axons and bouton-like swellings in the gray and white matters. Rostral to the lesion (at C3), the number of axon collaterals of the descending axons from both contralesional and ipsilesional M1 entering the ipsilesional and contralesional gray matter, respectively, were increased. Caudal to the lesion (at C8), axons originating from the contralesional M1, descending in the preserved gray matter around the lesion, and terminating in ipsilesional Laminae VI/VII and IX were observed. In addition, axons and terminals from the ipsilesional M1 increased in the ipsilesional Lamina IX after recrossing the midline, which were not observed in intact monkeys. Conversely, axons originating from the ipsilesional M1 and directed toward the contralesional Lamina VII decreased. These results suggest that multiple reorganizations of the corticospinal projections to spinal segments both rostral and caudal to the lesion originating from bilateral M1 underlie a prominent recovery in long-term after spinal cord injury

    Evaluation of the effects of mastication and swallowing on gastric motility using electrogastrography

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    Objectives : The influence of mastication and swallowing on gastric motor function was evaluated by electrogastrography (EGG) and abdominal ultrasonography. Methods: The subjects were 30 elderly patients with tubal feeding without mastication and swallowing (T group) and 30 elderly controls who processed food by mastication and swallowing (C group). Gastric motor function was percutaneously examined before and after the ingestion of 250 ml of a liquid diet using an electrogastrograph (NIPRO EGG, A&D, Tokyo, Japan). The cross-sectional area of the gastric antrum was measured at 1 and 30min after the start of ingestion of the liquid diet by external ultrasonography of the abdomen, and the gastric excretion function was evaluated. Furthermore, the spectral analysis of heart rate variability was performed using Holter electrocardiograms before and after ingestion. The low frequency power (LF power, 0.04-0.15 Hz), high frequency power (HF power, 0.15-0.40 Hz), and the LF/HF ratio were determined. Results: The peak amplitude at 3 cycles perminute (cpm)was significantly increased after ingestion in the C and T groups (p<0.05), and the ratio of increase was significantly lower in the T group (p<0.05). The mean amplitude for the brady-gastria and tachy-gastria was significantly higher in the T group than in the C group (p<0.05). The gastric excretion function, as evaluated by external ultrasonography of the abdomen, was significantly lower in the T group than in the C group (p<0.05). An analysis of heart rate variability demonstrated that the HF power, a parameter of parasympathetic activity, after ingestion was significantly higher in the C group than in the T group (p<0.05). No changes in LF power or LF/HF ratio, parameters of sympathetic activity, were induced by ingestion in either the C or T groups. Conclusions: The parasympathetic nerve dominantly controls gastric motor function, but autonomic nervous activity is reduced in patients who are unable to masticate and swallow food, resulting in adverse effects on gastric motor function and excretion function. Mastication and swallowing not only prepare food for passage from the oral cavity to the esophagus but are also important in terms of subsequent events that occur in stomach. It has been proposed that autonomic nervous activity might be involved in mastication and swallowing
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