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The pulse width modulation (PWM) in the inverter is an extremely important in power electronics. One of the problems in the PWM inverter is the existence of unwanted harmonics by switching. In this paper, a method to reduce this unwanted harmonic component, a modulation switching method, is proposed in which the modulation method is switched at the locations such as the peak of the reference sinusoidal signal. The PWM wave train is analyzed by a computer simulation as well as the theoretical analysis by the double fourier series expansion. It is show that the present method is effective in the reduction unwanted harmonic. Next, the characteristics of the modulation switching two-stage PWN sinusoidal inverter are investigated. [ABSTRACT FROM AUTHOR]

The ion temperature of the smallest tokamak, the major radius of 0.1 m, is measured using Doppler broadening spectroscopy. Experiments are performed for helium discharge. Ion temperature Ti = 0.7eV is obtained from the Doppler broadened line spectrum of the helium ion. The electron temperature and density measured using line emission intensities of the helium atom are Te = 4.7eV and ne = 3.2 × 1018m−3. The major radius R0 = 0.11m and the minor radius a = 0.03m are obtained from magnetic measurements. Then, the energy flow from the electron to the ion is evaluated as well as ohmic heating and power losses due to atomic processes. The main loss channel for electron stored energy is conduction even though the tokamak is immersed in the residual neutral gas. Total energy confinement time τE = 2.3µs is determined from the power balance, which is comparable with that deduced from the neo-Alcator scaling law. [ABSTRACT FROM AUTHOR]

Peripheral plasma electrostatic fluctuations are studied with an inserted electrostatic probe array in the STP-3(M) Reversed Field Pinch, and radial profiles of electron density, electron temperature, and plasma space potential are measured. The particle flux driven by electrostatic fluctuation is calculated with the correlation between the fluctuation of electron density and fluctuation of plasma space potential, yielding the result that the increase of electrostatic fluctuation at the edge causes particle diffusions. The agreement between the Er × B drift velocity of the radial electric field by the gradient of plasma space potential and the ion thermal velocity at the edge indicates ion motion dominates the particle diffusion. The decrease of the toroidal phase velocity at the edge and the confinement degradation shows the radial outside flow of the Er × Bp drift, where Et is generated by the toroidal flow fluctuation of the Er × B drift. Therefore, the electrostatic fluctuation caused by the radial propagation of plasma space potential is thought of as the dominance of the radial particle flux. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(1): 1–7, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ eej.20019 [ABSTRACT FROM AUTHOR]

Aim: The European Resuscitation Council guidelines recommend a slow rate of rewarming of 0.25 °C/h-0.5 °C/h for out-of-hospital cardiac arrest (OHCA) patients receiving therapeutic hypothermia (TH). Conversely, a very slow rewarming of 1 °C/day is generally applied in Japan. The rewarming duration ranged from less than 24 h up to more than 50 h. No randomized control trials have examined the optimal rewarming speed for TH in OHCA patients. Therefore, we examined the association between the rewarming duration and neurological outcomes in OHCA patients who received TH.Methods: This study was a secondary analysis of the Japanese Population-based Utstein-style study with defibrillation and basic/advanced Life Support Education and implementation-Hypothermia (J-PULSE-HYPO) study registry, a multicenter prospective cohort study. Patients suffering from OHCA who received TH (target temperature, 34 °C) after the return of spontaneous circulation from 2005 to 2011 in 14 hospitals throughout Japan were enrolled. The rewarming duration was defined as the time from the beginning of rewarming at a target temperature of 34 °C until reaching 36 °C. The primary outcome was an unfavorable neurological outcome at hospital discharge, i.e., a cerebral performance category of 3-5.Results: The J-PULSE-HYPO study enrolled 452 OHCA patients. Of these, 328 were analyzed; 79.9% survived to hospital discharge, of which 56.4% had a favorable neurological outcome. Multivariable logistic regression analysis revealed that the rewarming duration was independently associated with unfavorable neurological outcomes [odds ratio (per 5 h), 0.89; 95% confidence interval, 0.79-0.99; p =  0.032].Conclusion: A longer rewarming duration was significantly associated with and was an independent predictor of favorable neurological outcomes in OHCA patients who received TH. [ABSTRACT FROM AUTHOR]

Key Clinical Message Resuscitative endovascular balloon occlusion of the aorta ( REBOA) is a life-saving procedure used to control bleeding and maintain blood pressure temporarily in traumatic hemorrhagic shock. Uterine rupture and placenta accreta provoke uncontrollable massive hemorrhaging. REBOA may be useful for hemodynamic stabilization to prevent cardiac arrest in high-risk pregnancy. [ABSTRACT FROM AUTHOR]

Aim: This study investigated the value of regional cerebral oxygen saturation (rSO2) monitoring upon arrival at the hospital for predicting post-cardiac arrest intervention outcomes.Methods: We enrolled 1195 patients with out-of-hospital cardiac arrest of presumed cardiac cause from the Japan-Prediction of Neurological Outcomes in Patients Post-cardiac Arrest Registry. The primary endpoint was a good neurologic outcome (cerebral performance categories 1 or 2 [CPC1/2]) 90 days post-event.Results: A total of 68 patients (6%) had good neurologic outcomes. We found a mean rSO2 of 21%±13%. A receiver operating characteristic curve analysis indicated an optimal rSO2 cut-off of ≥40% for good neurologic outcomes (area under the curve 0.92, sensitivity 0.81, specificity 0.96). Good neurologic outcomes were observed in 53% (55/103) and 1% (13/1092) of patients with high (≥40%) and low (<40%) rSO2, respectively. Even without return of spontaneous circulation (ROSC) upon arrival at the hospital, 30% (9/30) of patients with high rSO2 had good neurologic outcomes. Furthermore, 16 patients demonstrating ROSC upon arrival at the hospital and low rSO2 had poor neurologic outcomes. Multivariate analyses indicated that high rSO2 was independently associated with good neurologic outcomes (odds ratio=14.07, P<0.001). Patients with high rSO2 showed favourable neurologic prognoses if they had undergone therapeutic hypothermia or coronary angiography (CPC1/2, 69% [54/78]). However, 24% (25/103) of those with high rSO2 did not undergo these procedures and exhibited unfavourable neurologic prognoses (CPC1/2, 4% [1/25]).Conclusion: rSO2 is a good indicator of 90-day neurologic outcomes for post-cardiac arrest intervention patients. [ABSTRACT FROM AUTHOR]

Aim: Our study aimed at filling the fundamental knowledge gap on the characteristics of regional brain oxygen saturation (rSO2) levels in out-of-hospital cardiac arrest (OHCA) patients with or without return of spontaneous circulation (ROSC) upon arrival at the hospital for estimating the quality of cardiopulmonary resuscitation and neurological prognostication in these patients.Methods: We enrolled 1921 OHCA patients from the Japan - Prediction of Neurological Outcomes in Patients Post-cardiac Arrest Registry and measured their rSO2 immediately upon arrival at the hospital by near-infrared spectroscopy using two independent forehead probes (right and left). We also assessed the percentage of patients with a good neurological outcome (defined as cerebral performance categories 1 or 2) 90 days post cardiac arrest.Results: After 90 days, 79 (4%) patients had good neurological outcomes and a median lower rSO2 level of 15% (15-20%). Compared to patients without ROSC upon arrival at the hospital, those with ROSC had significantly higher rSO2 levels (56% [39-65%] vs. 15% [15-17%], respectively; P<0.01), and significantly correlated right- and left-sided regional brain oxygen saturation levels (R=0.94 vs. 0.66, respectively). In both groups, the percentage of patients with a good 90-day neurological outcome increased significantly in proportion to their rSO2 levels upon arrival at the hospital (P<0.01).Conclusion: Our data indicate that measuring rSO2 levels might be effective for both monitoring the quality of resuscitation and neurological prognostication in patients with OHCA. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To investigate the association between regional brain oxygen saturation (rSO2) at hospital arrival and neurological outcomes at 90 days in patients with out-of-hospital cardiac arrest (OHCA). Methods: The Japan-Prediction of neurological Outcomes in patients post cardiac arrest (J-POP) registry is a prospective, multicenter, cohort study to test whether rSO2 predicts neurological outcomes after OHCA. We measured rSO2 in OHCA patients immediately after hospital arrival using a near-infrared spectrometer placed on the forehead with non-blinded fashion. The primary endpoint was “neurological outcomes” at 90 days after OHCA. Results: EMS providers are not permitted to terminate CPR in the field in Japan, and so most patients with OHCA who are treated by EMS personnel are transported to emergency hospitals. Among 1017 OHCA patients, 672 patients including 52 comatose patients with pulses detectable (8%) and 620 cardiac arrest patients (92%) at hospital arrival were enrolled prospectively and consecutively. Twenty-nine patients with good neurological outcome had a significantly higher value of rSO2 at hospital arrival than 643 patients with poor neurological outcome (mean [±SD] 55.6±20.8% vs. 19.7±11.0%, p <0.001). Receiver operating curve analysis indicated an optimal rSO2 cutoff point of >42% for predicting good neurological outcome, with sensitivity 0.79 (95% confidence interval [CI], 0.60–0.92), specificity 0.95 (95% CI, 0.93–0.96), positive predictive value, 0.41 (95% CI, 0.28–0.55), negative predictive value, 0.99 (95% CI, 0.98–1.00), and area under the curve 0.90 (95% CI, 0.88–0.92). Conclusion: The rSO2 at hospital arrival can predict good neurological outcome at 90 days after OHCA. [Copyright &y& Elsevier]

Objectives: Bradycardia during therapeutic hypothermia has been reported to be a predictor of favorable neurologic outcomes in out-of-hospital cardiac arrests. However, bradycardia occurrence rate may be influenced by the target body temperature. During therapeutic hypothermia, as part of the normal physiologic response, heart rate decreases in the cooling phase and increases during the rewarming phase. We hypothesized that increased heart rate during the rewarming phase is another predictor of favorable neurologic outcomes. To address this hypothesis, the study aimed to examine the association between heart rate response during the rewarming phase and neurologic outcomes in patients having return of spontaneous circulation after out-of-hospital cardiac arrest.Design: A secondary analysis of the Japanese Population-based Utstein style study with defibrillation and basic/advanced Life Support Education and implementation-Hypothermia registry, which was a multicenter prospective cohort study.Setting: Fourteen hospitals throughout Japan.Patients: Patients suffering from out-of-hospital cardiac arrest who received therapeutic hypothermia after the return of spontaneous circulation from 2005 to 2011.Intervention: None.Measurements and Main Results: This study enrolled 452 out-of-hospital cardiac arrest patients, of which 354 were analyzed, and 80.2% survived to hospital discharge, of which 57.3% had a good neurologic outcome. Heart rate response was calculated using heart rate data recorded during therapeutic hypothermia in the abovementioned registry. Heart rate response in the rewarming phase (heart rate response-rewarming) was calculated as follows: (heart rate [post rewarming]-heart rate [pre rewarming])/heart rate (pre rewarming) × 100. The primary outcome was an unfavorable neurologic outcome at hospital discharge, that is, a Cerebral Performance Category of 3-5. Multivariable logistic regression analysis was performed to determine the association between heart rate response-rewarming and unfavorable neurologic outcomes. Multivariable logistic regression analysis showed that heart rate response-rewarming was independently associated with unfavorable outcomes (odds ratio [per 10% change], 0.86; 95% CI, 0.78-0.96; p = 0.004).Conclusions: Increased heart rate in the approximately 48-hour rewarming phase during therapeutic hypothermia was significantly associated with and was an independent predictor of favorable neurologic outcomes during out-of-hospital cardiac arrest. [ABSTRACT FROM AUTHOR]