Electrical detection of parallel parametric amplification and attenuation in Y3Fe5O12\mathrm{Y}_3\mathrm{Fe}_5\mathrm{O}_{12}/Pt\mathrm{Pt} bilayer disk

We report a systematic quantitative evaluation of parametric amplification gain of magnetization dynamics in ytirrium iron garnet ($\mathrm{Y}_3\mathrm{Fe}_5\mathrm{O}_{12}$) thin disk via a.c. spin pumping and inverse spin Hall effect. We demonstrate its signature phase-dependence where amplification and attenuation occur every $\frac{\pi}{2}$ phase shift of the input signal. The results also show the pump-power dependence of the gain that is explained well by our theoretical model. Finally, the optimal conditions for the amplification is investigated by measuring the magnetic field dependence, where we find the highest gain of 11.4 dB.Comment: 6 pages, 3 figures, 14 panel

Switching of magnon parametric oscillation by magnetic field direction

Parametric oscillation occurs when the resonance frequency of an oscillator is periodically modulated. Owing to time-reversal symmetry breaking in magnets, nonreciprocal magnons can be parametrically excited when spatial-inversion symmetry breaking is provided. This means that magnons with opposite propagation directions have different amplitudes. Here we demonstrate switching on and off the magnon parametric oscillation by reversing the external field direction applied to a Y$_3$Fe$_5$O$_{12}$ micro-structured film. The result originates from the nonreciprocity of surface mode magnons, leading to field-direction dependence of the magnon accumulation under a nonuniform microwave pumping. Our numerical calculation well reproduces the experimental result.Comment: 5 pages, 4 figure

Two-photon excitable boron complex based on tridentate imidazo[1,5-a]pyridine ligand for heavy-atom-free mitochondria-targeted photodynamic therapy

We have synthesized a cyan fluorescent boron complex based on a tridentate imidazo[1,5-a]pyridine ligand. The boron complex was found to have potential applications as not only a chiroptical material but also a heavy-atom-free mitochondria-targeted photosensitizer for cancer treatment

Preventive effect of statin pretreatment on contrast-induced acute kidney injury in patients undergoing coronary angioplasty: Propensity score analysis from a multicenter registry

BackgroundThe prophylactic benefit of statins in reducing the incidence of contrast-induced acute kidney injury (CI-AKI) has been investigated in several studies with conflicting results. We sought to investigate whether statin pretreatment prevents CI-AKI in coronary artery disease (CAD) patients undergoing percutaneous coronary intervention (PCI).MethodsA total of 2198 CAD patients who underwent PCI, except for those undergoing dialysis or who died within 7 days after angioplasty, were analyzed from the ICAS (Ibaraki Cardiovascular Assessment Study) multicenter registry. Analyzed subjects were divided into 2 groups according to statin pretreatment: statin pretreatment (n = 839) and non-statin pretreatment (n = 1359). Selection bias of statin pretreatment was adjusted by propensity score-matching method: pretreatment statin (n = 565) and non-statin pretreatment (n = 565). CI-AKI was defined as an increase in serum creatinine of ≥ 25% or 0.5 mg/dl from baseline within 1 week of contrast medium exposure.ResultsA total of 192 (8.7%) patients developed CI-AKI. No significant differences were observed in baseline patient characteristics between the statin and non-statin pretreatment groups after propensity score matching. In the propensity score-matched groups, the incidence of CI-AKI was significantly lower in patients with statin pretreatment than in those without statin pretreatment (3.5% vs.10.6%, odds ratio [OR]: 0.31, 95% confidence interval [CI]: 0.18–0.52, P < 0.001). Multivariate logistic regression analysis showed that statin pretreatment remained an independent negative predictor of CI-AKI (OR: 0.31, 95% CI: 0.18–0.53, P < 0.001) among propensity score-matched subjects.ConclusionsStatin pretreatment was associated with a significant decrease in the risk of CI-AKI in CAD patients undergoing PCI in the ICAS Registry

Impact of Coronary Plaque Composition on Cardiac Troponin Elevation After Percutaneous Coronary Intervention in Stable Angina Pectoris : A Computed Tomography Analysis

ObjectivesThe authors used multidetector computed tomography (MDCT) to study the relation between culprit plaque characteristics and cardiac troponin T (cTnT) elevation after percutaneous coronary intervention (PCI).BackgroundPercutaneous coronary intervention is often complicated by post-procedural myocardial necrosis manifested by elevated cardiac biomarkers.MethodsStable angina patients (n = 107) with normal pre-PCI cTnT levels underwent 64-slice MDCT before PCI to evaluate plaque characteristics of culprit lesions. Patients were divided into 2 groups according to presence (group I, n = 36) or absence (group II, n = 71) of post-PCI cTnT elevation ≥3 times the upper limit of normal (0.010 ng/ml) at 24 h after PCI.ResultsComputed tomography attenuation values were significantly lower in group I than in group II (43.0 [26.5 to 75.7] HU vs. 94.0 [65.0 to 109.0] HU, p 1.05; odds ratio: 4.54; 95% confidence interval: 1.36 to 15.9; p = 0.014) and spotty calcification (odds ratio: 4.27; 95% confidence interval: 1.30 to 14.8; p = 0.016) were statistically significant independent predictors for cTnT elevation. For prediction of cTnT elevation, the presence of all 3 variables (CT attenuation value 1.05, and spotty calcification) showed a high positive predictive value of 94%, and their absence showed a high negative predictive value of 90%.ConclusionsMDCT may be useful in detecting which lesions are at high risk for myocardial necrosis after PCI

Changes in Cerebral Hemodynamics during Complex Motor Learning by Character Entry into Touch-Screen Terminals

Introduction Studies of cerebral hemodynamics during motor learning have mostly focused on neurorehabilitation interventions and their effectiveness. However, only a few imaging studies of motor learning and the underlying complex cognitive processes have been performed. Methods We measured cerebral hemodynamics using near-infrared spectroscopy (NIRS) in relation to acquisition patterns of motor skills in healthy subjects using character entry into a touchscreen terminal. Twenty healthy, right-handed subjects who had no previous experience with character entry using a touch-screen terminal participated in this study. They were asked to enter the characters of a randomly formed Japanese syllabary into the touchscreen terminal. All subjects performed the task with their right thumb for 15 s alternating with 25 s of rest for 30 repetitions. Performance was calculated by subtracting the number of incorrect answers from the number of correct answers, and gains in motor skills were evaluated according to the changes in performance across cycles. Behavioral and oxygenated hemoglobin concentration changes across task cycles were analyzed using Spearman\u27s rank correlations. Results Performance correlated positively with task cycle, thus confirming motor learning. Hemodynamic activation over the left sensorimotor cortex (SMC) showed a positive correlation with task cycle, whereas activations over the right prefrontal cortex (PFC) and supplementary motor area (SMA) showed negative correlations. Conclusions We suggest that increases in finger momentum with motor learning are reflected in the activity of the left SMC. We further speculate that the right PFC and SMA were activated during the early phases of motor learning, and that this activity was attenuated with learning progress

Origins of multisynaptic projections from the basal ganglia to the forelimb region of the ventral premotor cortex in macaque monkeys

The ventral premotor cortex (PMv), occupying the ventral aspect of area 6 in the frontal lobe, has been implicated in action planning and execution based on visual signals. Although the PMv has been characterized by cortico-cortical connections with specific subregions of the parietal and prefrontal cortical areas, a topographical input/output organization between the PMv and the basal ganglia (BG) still remains elusive. In the present study, retrograde transneuronal labelling with the rabies virus was employed to identify the origins of multisynaptic projections from the BG to the PMv. The virus was injected into the forelimb region of the PMv, identified in the ventral aspect of the genu of the arcuate sulcus, in macaque monkeys. The survival time after the virus injection was set to allow either the second- or third-order neuron labelling across two or three synapses. The second-order neurons were observed in the ventral portion (primary motor territory) and the caudodorsal portion (higher-order motor territory) of the internal segment of the globus pallidus. Subsequently, the third-order neurons were distributed in the putamen caudal to the anterior commissure, including both the primary and the higher-order motor territories, and in the ventral striatum (limbic territory). In addition, they were found in the dorsolateral portion (motor territory) and ventromedial portion (limbic territory) of the subthalamic nucleus, and in the external segment of the globus pallidus including both the limbic and motor territories. These findings indicate that the PMv receives diverse signals from the primary motor, higher-order motor and limbic territories of the BG