216 research outputs found

    分子光電変換デバイスを指向した自己組織化有機・無機材料

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    京都大学0048新制・課程博士博士(工学)甲第16878号工博第3599号新制||工||1543(附属図書館)29553京都大学大学院工学研究科分子工学専攻(主査)教授 今堀 博, 教授 佐藤 啓文, 教授 梶 弘典学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDFA

    The application of tetanic stimulation of the unilateral tibial nerve before transcranial stimulation can augment the amplitudes of myogenic motor-evoked potentials from the muscles in the bilateral upper and lower limbs.

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    BACKGROUND: Recently, we reported a new technique to augment motor-evoked potentials (MEPs) under general anesthesia, posttetanic MEP (p-MEP), in which tetanic stimulation of the peripheral nerve before transcranial stimulation enlarged amplitudes of MEPs from the muscle innervated by the nerve subjected to tetanic stimulation. In the present study, we tested whether tetanic stimulation of the left tibial nerve can also augment amplitudes of MEPs from the muscles which are not innervated by the nerve subjected to tetanic stimulation. METHODS: Thirty patients undergoing spinal surgery under propofol-fentanyl anesthesia with partial neuromuscular blockade were examined. For conventional MEP (c-MEP) recording, transcranial stimulation with train-of-five pulses was delivered to C3-4, and the compound muscle action potentials were bilaterally recorded from the abductor pollicis brevis, abductor hallucis (AH), tibialis anterior, and soleus muscles. For p-MEP recording, tetanic stimulation (50 Hz, 50 mA of stimulus intensity) with a duration of 5 s was applied to the left tibial nerve at the ankle 1 s before transcranial stimulation. Transcranial stimulation and recording of compound muscle action potentials were performed in the same manner as c-MEP recording. Amplitudes of c-MEP and p-MEP were compared using Wilcoxon's signed rank test. RESULTS: Amplitudes of p-MEPs from the left AH muscle innervated by the left tibial nerve with tetanic stimulation were significantly larger compared with those of c-MEPs. Amplitudes of p-MEPs from the bilateral abductor pollicis brevis and soleus muscles and right AH and tibialis anterior muscles, which were not innervated by the left tibial nerve with tetanic stimulation, were also significantly larger compared with those of c-MEPs. CONCLUSION: In patients under propofol and fentanyl anesthesia with partial neuromuscular blockade, the application of tetanic stimulation to the left tibial nerve augmented the amplitudes of MEPs from the muscles without tetanic nerve stimulation and those with stimulation.博士(医学)・乙第1317号・平成25年7月22

    頚椎手術術中神経モニタリングにおける偽陽性減少を目的とした顔面運動誘発電位の応用

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    Objective: False-positive intraoperative muscle motor evoked potential (mMEP) monitoring results due to systemic effects of anesthetics and physiological changes continue to be a challenging issue. Although control MEPs recorded from the unaffected side are useful for identifying a true-positive signal, there are no muscles on the upper or lower extremities to induce control MEPs in cervical spine surgery. Therefore, this study was conducted to clarify if additional MEPs derived from facial muscles can feasibly serve as controls to reduce false-positive mMEP monitoring results in cervical spine surgery. Methods: Patients who underwent cervical spine surgery at the authors' institution who did not experience postoperative neurological deterioration were retrospectively studied. mMEPs were induced with transcranial supramaximal stimulation. Facial MEPs (fMEPs) were subsequently induced with suprathreshold stimulation. The mMEP and subsequently recorded fMEP waveforms were paired during each moment during surgery. The initial pair was regarded as the baseline. A significant decline in mMEP and fMEP amplitude was defined as > 80% and > 50% decline compared with baseline, respectively. All mMEP alarms were considered false positives. Based on 2 different alarm criteria, either mMEP alone or both mMEP and fMEP, rates of false-positive mMEP monitoring results were calculated. Results: Twenty-three patients were included in this study, corresponding to 102 pairs of mMEPs and fMEPs. This included 23 initial and 79 subsequent pairs. Based on the alarm criterion of mMEP alone, 17 false-positive results (21.5%) were observed. Based on the alarm criterion of both mMEP and fMEP, 5 false-positive results (6.3%) were observed, which was significantly different compared to mMEP alone (difference 15.2%; 95% CI 7.2%-23.1%; p < 0.01). Conclusions: fMEPs might be used as controls to reduce false-positive mMEP monitoring results in cervical spine surgery.博士(医学)・甲第746号・令和2年6月30日© Copyright 2019 American Association of Neurological SurgeonsThe definitive version is available at " http://dx.doi.org/10.3171/2019.9.SPINE19800

    Regulation of Mesodermal Differentiation of Mouse Embryonic Stem Cells by Basement Membranes

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    This research was originally published in the Journal of Biological Chemistry. Hironobu Fujiwara, Yoshitaka Hayashi, Noriko Sanzen, Reiko Kobayashi, Charles N. Weber, Tomomi Emoto, Sugiko Futaki, Hitoshi Niwa, Patricia Murray, David Edgar and Kiyotoshi Sekiguchi. Regulation of Mesodermal Differentiation of Mouse Embryonic Stem Cells by Basement Membranes. J. Biol. Chem. 2007; 282: 29701–29711 © the American Society for Biochemistry and Molecular Biolog

    On-surface synthesis and characterization of nitrogen-substituted undecacenes

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    Heteroatom substitution in acenes allows tailoring of their remarkable electronic properties, expected to include spin-polarization and magnetism for larger members of the acene family. Here, we present a strategy for the on-surface synthesis of three undecacene analogs substituted with four nitrogen atoms on an Au(111) substrate, by employing specifically designed diethano-bridged precursors. A similarly designed precursor is used to synthesize the pristine undecacene molecule. By comparing experimental features of scanning probe microscopy with ab initio simulations, we demonstrate that the ground state of the synthesized tetraazaundecacene has considerable open-shell character on Au(111). Additionally, we demonstrate that the electronegative nitrogen atoms induce a considerable shift in energy level alignment compared to the pristine undecacene, and that the introduction of hydro-aza groups causes local anti-aromaticity in the synthesized compounds. Our work provides access to the precise fabrication of nitrogen-substituted acenes and their analogs, potential building-blocks of organic electronics and spintronics, and a rich playground to explore π-electron correlation

    Control of Domain Wall Position by Electrical Current in Structured Co/Ni Wire with Perpendicular Magnetic Anisotropy

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    We report the direct observation of the current-driven domain wall (DW) motion by magnetic force microscopy in a structured Co/Ni wire with perpendicular magnetic anisotropy. The wire has notches to define the DW position. It is demonstrated that single current pulses can precisely control the DW position from notch to notch with high DW velocity of 40 m/s.Comment: 12 pages, 3 figure
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