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The discovery of new antimalarial drugs can be developed using asynchronized Plasmodium berghei malaria parasites in vivo in mice. Studies on a particular stage are also required to assess the effectiveness and mode of action of drugs. In this report, we used endoperoxide 6-(1,2,6,7-tetraoxaspiro [7.11] nonadec-4-yl) hexan-1-ol (N-251) as a model antimalarial compound on P. chabaudi parasites. We examined the antimalarial effect of N-251 against ring-stage- and trophozoite-stage-rich P. chabaudi parasites and asynchronized P. berghei parasites using the 4-day suppressive test. The ED50 values were 27, 22, and 22 mg/kg, respectively, and the antimalarial activity of N-251 was verified in both rodent malaria parasites. To assess the stage-specific effect of N-251 in vivo, we evaluated the change of parasitemia and distribution of parasite stages using ring-stage- and trophozoite-stage-rich P. chabaudi parasites with one-day drug administration for one life cycle. We discovered that the parasitemias decreased after 13 and 9 hours post-treatment in the ring-stage- and trophozoite-stage-rich groups, respectively. Additionally, in the ring-stage-rich N-251 treated group, the ring-stage parasites hindered trophozoite parasite development. For the trophozoite-stage-rich N-251 treated group, the distribution of the trophozoite stage was maintained without a change in parasitemia until 9 hours. Because of these findings, it can be concluded that N-251 suppressed the trophozoite stage but not the ring stage. We report for the first time that N-251 specifically suppresses the trophozoite stage using P. chabaudi in mice. The results show that P. chabaudi is a reliable model for the characterization of stage-specific antimalarial effects.

The discovery of new effective and safe antimalarial drugs is mandatory. In this report, we formulate and evaluate transdermal (td) 1,2,6,7-tetraoxaspiro[7.11]nonadecane (N-89) using the Plasmodium berghei rodent malaria parasite in vivo model. The selected solvent for the ointment type of td N-89 was polyethylene glycol (PEG) [PEG400:PEG 4000 = 8:1 (v/w)]. We tested different application areas of 4, 6, and 8 cm

Surgery with both anterior and posterior fixation is recommended for unstable pelvic ring fractures; nonetheless, the surgical method remains controversial. Crab-shaped fixation is a minimally invasive and strong posterior fixation method using spinal instruments that can reduce vertical dislocations. The use of pelvic internal fixator as a minimally invasive anterior fixation method has been reported. It is recommended in cases where there is an open wound in the lower abdomen or damage to the pelvic organs. Conversely, to the best of our knowledge, there has been no report on the combined use of crab-shaped fixation and pelvic internal fixator to date. We performed a minimally invasive 360-degree fixation using a combination of crab-shaped fixation and pelvic internal fixator for an unstable pelvic ring fracture (AO-C2) and sacral fracture (Denis zone II) with 15-mm vertical dislocation. The sacral fracture was accompanied by a large bone fragment in the spinal canal, which was suspected to have caused neuropathy. Therefore, in addition to posterior fixation, we performed decompression and removed the bone fragment. Postoperative computed tomography revealed that the sacral vertical dislocation was reduced to 7.5 mm. The patient started getting out of bed on postoperative day 2. His neuropathy improved after surgery. Owing to abdominal discomfort, pelvic internal fixator was extracted at 3 months postoperatively. Bone fusion was completed, and posterior fixation was removed at 9 months postoperatively. Two years after, the patient walks independently and has returned to work. Minimally invasive 360-degree pelvic ring fixation is a treatment option for an unstable pelvic ring fracture (AO-C2)., Highlights • CSF360 is a modified CSF surgical technique. • Free bone fragment and 360° pelvic ring fixation CSF and INFIX were performed. • Unstable pelvic ring fractures can be fixed to 360° of circumference.

A premium class electric vehicle (EV) needs high drive system efficiency, low motor noise and limp-home capability of the traction drive when there is a component failure. A dual inverter fed open winding interior permanent magnet synchronous motor (DIF-OW-IPMSM) drive system satisfied all the above needs. In this paper, a new algorithm of inverter open-circuit fault diagnosis and fail-safe action strategy for the DIFOW-IPMSM drive system are proposed and presented to prove its high reliability. The proposed new algorithm is verified by suitable simulation and experimental results, and the safe limp-home capability of the DIF-OW-IPMSM drive system is demonstrated.

The dual inverter fed open winding interior permanent magnet synchronous motor (DIF-OW-IPMSM) is a promising traction drive system configuration for a high power and high efficiency electric vehicle. In this paper, a new PWM switching strategy of the inverters is presented when the motor is operating in the medium and high speed region. The PWM switching strategy consists of operating one of the inverters in the low switching frequency 1 pulse (square wave) mode and the other inverter in the high switching frequency specialized continuous pulse width modulation (SCPWM). The new PWM strategy has been verified from suitable simulation and experimental results in the medium speed range. Finally, a dual inverter configuration with a hybrid combination of Si IGBT inverter and SiC MOSFET inverter is recommended for a premium class electric vehicle to improve the drive system efficiency.

This paper focuses on a hybrid excitation flux switching motor (HEFSM) using variably magnetizable permanent magnets (VM-PMs) as variable flux motors for EV/HEV propulsion. The HEFSM makes an energization of field excitation coil unnecessary for most of the operating conditions so that it enlarges high efficiency operating area thanks to reductions of both copper and iron losses by adequately controlling magnetization state of the VM-PMs according to given operating conditions. In this paper, a new HEFSM design is proposed, which employs a novel PM arrangement as well as a flat motor shape with an optimum L/D ratio aiming at total PM usage reduction and the variable flux capability and maximum torque improvement. FEA-based simulation results show that the motor efficiency and variable flux capability of the proposed HEFSM are comparable with those of a previous PM-rich HEFSM while satisfying the target maximum torque and demagnetization tolerability of PMs under the total PM usage limitation.

Design and experimental studies on a hybrid excitation flux switching motor as a traction motor for hybrid electric vehicles drive are presented. A stator body of the motor consists of not only laminated silicon-iron electromagnetic steel and three-phase armature windings, but also both of field excitation coils and permanent magnets working together as a variable field magnetomotive force source. On the other hand, a rotor is composed of just laminated silicon-iron electromagnetic steel with salient poles like switched reluctance motor. To bring out the best in drive performances of the hybrid excitation flux switching motor as a variable flux motor for the application, each material adopted for the stator and rotor body should be designed properly in terms of motor efficiency, maximum torque and power densities and so forth. As some of them, in this paper, thinner silicon-iron electromagnetic steel sheet and permanent magnets with high remanent and low amount of Dysprosium used are applied for achieving higher motor efficiency. Moreover, all coils wound flatwise and edgewise using rectangular wires are introduced to realizing high filling factor for reduced copper losses. Experimental tests using a 60kW prototype of the motor demonstrates the designed motor has good motor efficiency under frequent operating points expected for the target vehicle drive.

This paper presents the magnetization state control of variably magnetizable-permanent magnets (VM-PM) - for a hybrid excitation flux switching motor (HEFSM) at the initial starting up. The HEFSM employing $N_{d}-F_{e}-B$ type magnets with low coercive force as VM-PMs can achieve higher efficiency driving over the whole operating area compared with the conventional HEFSM without VM-PMs by appropriately adjusting the magnetization state according to a given operating condition. To put such the HEFSM into practical use for automotive traction applications, it is essential to be able to intentionally control the magnetization state by applying a pulsewise current to field excitation coil (FEC) during rotation as well as at starting up aiming at initialization of the magnetization state of VM-PMs. At first, a difference in the magnetization state controllability during middle-speed rotation and at a standstill and the angular dependence of the magnetizing magnetic field applied on VM-PM are investigated and discussed. Subsequently, the “quasi-impulse current train magnetization method” at starting up is proposed as a novel magnetization state control scheme. The effectiveness of the proposed control scheme is experimentally verified using a 60kW test motor. As a result, it is revealed that the magnetization control at the starting up can be achieved similar to that during the middle-speed rotation.

This paper presents an isolated step-down DCDC converter using GaN power devices for automobile applications. This converter consists of a LLC converter and a boost chopper converter and supplies power from the high voltage of the motor drive battery at 200V to the low voltage of the sub battery at 13.6V for the auxiliary system in a hybrid electric vehicle. Both converters perform the soft switching operation and achieve high conversion efficiency. However, the boost chopper circuit does not succeed in soft switching and has lower efficiency in the high-power range. In addition, the inrush current flow to the GaN power device can damage the device.Thus, we formulated soft switching conditions and proposed a control method that adjusts the switching frequency to expand the soft-switching operation range. The proposed method achieved a high efficiency of 99 % even in at high power and expanded the output range in the experimental test.

This paper presents the design method for a three-phase pulse width modulation (PWM) inverter with an AC filter inductor. In general, increasing the switching frequency is known to increase the switching device loss and decrease the volume of the passive components. An inverter design should consider the balance between conversion efficiency and inverter volume. However, as per our knowledge, no study has focused on the optimal design of a PWM inverter that includes an AC filter inductor. This is because the iron loss of the AC filter inductor changes in complicated ways depending on the switching ripple current, DC-bias excitation, etc. The authors clarified this iron loss mechanism and realized a highly accurate iron loss calculation method. Therefore, in this study, we designed a three-phase PWM inverter with an AC filter based on the switching frequency. The design method is confirmed by comparing the simulation and experimental results.

In this paper, design and experimental studies on a hybrid excitation flux switching motor (HEFSM) are presented. The motor with a piece of permanent magnet per pole being comprised of two different types of permanent magnets is employed for protecting its demagnetization un-der high temperature and heavy load situation as well as better motor efficiency. One is with high residual flux density and low coercive force for the purpose of reduction the copper loss. The other is with relatively low flux density and high coercive force, by which the demagnetization is mitigated. Finite element analysis- and experimental test-based performance evaluations validate that the designed motor achieves better motor efficiency while satisfying the target specifications required for automotive traction drive applications.

This paper deals with a hybrid excitation flux switching motor (HEFSM) employing a variably magnetizable permanent magnet as an automobile traction motor for a hybrid electric vehicle. Compared with the conventional HEFSM, a difference can be found on the stator body that newly utilizes the variably magnetizable permanent magnets adding to the conventional parts such as laminated steel core, three-phase armature coils, field excitation coils and constantly magnetized permanent magnets. A basic concept to improve motor efficiency is based on replacing the mmf of field excitation coils with that of the variably magnetizable permanent magnets. The magnetizing state of the variably magnetizable permanent magnet is adjusted properly according to operating conditions, resulting in the copper loss and iron loss reductions. FEA-based design and simulation as well as experimental test-based performance evaluation results of the proposed HEFSM show that the motor efficiencies under frequent operating conditions compete with those of the IPMSM installed on TOYOTA fourth-generation PRIUS.

A dual inverter-fed open winding interior permanent magnet synchronous motor employing a dual battery source is found to be a promising drive system configuration for a high-power premium class electric vehicle. From the standpoints of high drive system efficiency and low motor acoustic noise, in this paper, selection of different optimum PWM switching modes according to the vehicle driving states is proposed for such a drive system configuration. Suitable simulation and experimental results for the motor drive system with 65 kW are presented to validate the proposed selection of different optimum PWM switching modes based on the vehicle driving states.

Aluminum electrolytic capacitors used in power electronics converters are a major factor that reduce the reliability of these devices. To evaluate the lifetime and reliability of this type of capacitors, capacitor loss needs to be evaluated under the excitation conditions of power electronics converters. However, the capacitor loss data provided by manufacturers is always measured under sinusoidal excitation. The authors therefore proposed a capacitor loss evaluation method for arbitrary excitation waveforms found in power electronics converters. This method features a simple configuration, and the capacitor loss can be practically evaluated using a function generator without the need of a real power electronics converter. Therefore, the capacitor loss can be analyzed under different conditions, ranging from fundamental analysis to practical analysis, for instance, pulse-width modulated (PWM) inverter excitation. In this study, the capacitor loss was evaluated using fundamental excitation and (PWM) inverter excitation. Moreover, the capacitor loss of four different type of capacitors was assessed. Under PWM inverter excitation, nonlinear loss behaviors were observed. Nonlinear loss characteristics could be expressed using a hysteresis curve in the Q-V plane. It was found that the hysteresis curves changed when the rectangular excitation current had zero current phases and different duty ratios due to the voltage unbalance of the tunnel pit capacitance in the capacitor sheets.

A capacitor is a major component that contributes to reducing the reliability of high-power density power electronics converters. The lifetime and reliability of capacitors are strongly influenced by temperature. An accurate loss measurement method is necessary to estimate temperature rise. However, practical capacitor loss measurement systems used in power electronics converters have not yet been developed because capacitor loss data provided by the manufacturer is usually measured under sinusoidal excitation, which is different from actual excitations of electronics converters. In this study, a capacitor loss measurement system for power electronics converters is proposed. The proposed measurement system can be used for fast capacitor loss measurement with high accuracy in a real circuit and capacitor loss analysis for each switching period of power electronics converters. To verify the accuracy of the loss measurement, the measured loss value of a filter capacitor used in a pulse width modulated inverter is compared with the calculated value. The experimental results show good agreement with the calculated capacitor loss.

Aims In this study, we examined whether a disruption in the balance between nitric oxide (NO)-sensitive and -insensitive soluble guanylate cyclase (sGC) is observed in pulmonary hypertension (PH) and whether treatment with NO-enhancing drugs can halt disease progression. Main methods Rats were injected subcutaneously with saline or 60 mg/kg monocrotaline (MCT). At 14 days after injection, the vascular reactivity of isolated extralobar pulmonary arteries was assessed by organ chamber technique. In a separate experiment, isosorbide mononitrate (0.3 or 1 g/L) or sodium nitrite (30 or 300 mg/L) was administered in drinking water for the last 14 days (from day 15 to day 28), and their therapeutic potential was evaluated. Key findings The NO-sensitive sGC stimulant BAY 41-2272 and the NO-insensitive sGC stimulant BAY 60-2770 both relaxed the pulmonary arteries, which was comparable between saline- and MCT-injected rats. Treatment with isosorbide mononitrate suppressed the MCT-induced right ventricular systolic pressure (RVSP) elevation and pulmonary arterial medial thickening but not right ventricular hypertrophy. However, the beneficial effects on RVSP and pulmonary vascular remodeling were not observed when a high dose was administered. The same results were obtained following the sodium nitrite treatment. Interestingly, NO-enhancing drugs did not increase plasma nitrite plus nitrate levels at a dose that provided the greatest therapeutic advantage. Significance These findings suggest that the balance between NO-sensitive and -insensitive sGC is not disrupted in the early stage of MCT-induced PH. Furthermore, supplementation with an adequate amount of NO may be a useful therapy to prevent the progression of PH.

A main source producing noise and vibration in a switched reluctance motor is time variation of radial force acting on stator tooth during excitation period. Based on this principle, two different control are examined and compared in this paper. One is two-stage commutation method well-known as active vibration cancellation technique and the other is flux profiling control. The flux profiling control proposed in this study considers an increased degree of freedom of flux profile with superposition of lower order harmonics. The parameters for flux profile are optimized by genetic algorithm to minimize vibration and acoustic noise while keeping target torque and minimizing power loss as well as torque ripple. Experimental studies on drive performance comparisons under different control using 50kW three-phase 18/12 test motor are carried out. As a result, the proposed control employing the optimized flux profile works better than the conventional two stage commutation method in terms of higher motor efficiency, reduced noise and vibration, and less torque pulsation.

This paper presents an iron loss calculation method for SiFe steel material under high-frequency current ripple due to PWM switching. The PWM switching produces dynamic minor loops on the BH plane, which cause iron loss. In this study, the improved Bertotti's physical model is used for iron loss calculation for dynamic minor loops in SiFe steel material. The calculated iron loss values are compared with the measured iron loss values. The model predicts the iron loss within an acceptable error. However, calculation errors are found when comparing the iron loss value for each dynamic minor loop. The reason for the calculation errors is that the measured iron loss varies if the flux density bias is different, even if the DC-bias has the same value. The calculation error occurs not only in the improved Bertotti's physical model but also in other methods such as improved Steinmetz equation because these methods do not take into account the flux density bias and/or the DC-bias characteristic.

This paper presents an isolated step-sown DC-DC converter using GaN power device for automotive applications. The works for a power supply from a high voltage main battery with 200V to low voltage auxiliary battery with 13.6V in hybrid electric vehicle. A LLC converter is known as isolated DC-DC converter with high-efficiency. However, when input and/or output voltage considerably fluctuates, efficiency of a LLC resonant converter becomes worse. In order to solve this problem, a DC-DC boost-up converter to mitigate efficiency deterioration for the input and/or output voltage fluctuation is added to a LLC resonant converter. Generally speaking, an additional circuit, the boost-up chopper in this case, also deteriorates the total system efficiency. To avoid the efficiency degradation, discontinuous current mode control and GaN power devices are applied to the boost-up chopper. The DC-DC boost-up converter experimentally achieves 99.03% of conversion efficiency at nominal output so that it has no effect on the total system efficiency. Even though adding a DC-DC boost-up chopper to the LLC resonant converter, a power density expected to 10 W/cc.

Background Unstable sacral fractures are high-energy injuries and comprise polytrauma. Internal fixation to enable withstanding vertical loads is required to get up early from the bed after an unstable sacral fracture. We developed a new minimally invasive surgical (MIS) procedure for unstable pelvic ring fractures and reported it in Japanese in 2010. We presented our minimally invasive surgical technique of crab-shaped fixation for the treatment of unstable pelvic ring fractures and report on its short-term outcomes. Methods Sixteen patients with unstable pelvic ring fractures (AO types C1, 2, and 3) were treated using crab-shaped fixation. All procedures were performed with the patient in the prone position through 5-cm skin incisions created bilaterally at the level of the posterior superior iliac spine. Four iliac screws were inserted and connected with two rods under the fascia. Percutaneous pedicle screws were inserted at L5 or L4 and connected to the iliac rod using offset connectors. Fracture reduction was then performed. Results The average surgical time was 158 min (range, 117–230 min), with an intraoperative bleeding volume of 299 ml (range, 80–480 ml). Thirty-three pedicle screws and 64 iliac screws were implanted with no instance of malpositioning or perforation. A surgical site infection developed in 2 of the 16 cases. Both were deep methicillin-resistant Staphylococcus aureus infections, with the removal of the distal implants required in only one of these cases. Bony union was achieved in all patients, and all vertical displacements reduced by 7.0 mm, on average (range, 5.4–9.0 mm), to

This study was conducted to develop a design method of power density and efficiency maximization for three-phase pulse-width modulated (PWM) inverters that include AC filter. A tradeoff relationship exists between power density and efficiency. In general, increasing the switching frequency is known to increase the switching device loss and decrease the volume of the passive components. A three-phase PWM inverters design should consider the balance between conversion efficiency and inverter volume. However, best of our knowledge, no practical study has focused on the optimal design of a three-phase PWM inverter that includes an AC filter. This is because the iron loss of the AC filter inductor changes in complicated ways depending on the DC-bias excitation, amplitude of switching ripple current, etc. Therefore, the present authors clarified this iron loss mechanism and realized a highly accurate iron loss calculation method in previous studies. In this paper, the relationship between efficiency and volume for the switching frequency was analyzed when the AC filter inductor was designed for minimal loss by adjusting the core diameter, height, and number of winding turns. The efficiency and volume optimization achieved by designing a proper inductor was verified via comparison with a base design.

The authors have proposed two methods for iron loss evaluation of the ac filter inductor used in a pulsewidth modulation (PWM) inverter. The first method is a loss map method, which can be used for the iron loss calculation of the ac filter inductor without using a real PWM inverter, and the second method is an iron loss analyzer (ILA), which can measure the iron loss of the ac filter inductor during every switching period on a real PWM inverter. In this paper, the measurement results obtained using the ILA and the results calculated using the loss map method on both the single-phase and three-phase inverters are compared. The calculated iron loss of the ac filter inductor on the three-phase PWM inverter is found to have a relatively large error for certain PWM pulse conditions. In order to reduce the calculation error, the authors propose a modified loss calculation method and demonstrate that the calculation error is reduced to less than 2%.

Design and experimental studies on Hybrid Excitation Flux Switching Motor (HEFSM) applied to a traction motor for hybrid electric vehicles are presented. A stator body of HEFSM generally consists of not only laminated core and three-phase armature coils, but also field excitation coils and permanent magnets as field mmf sources. Therefore, each material used in the stator body should be designed properly with the purpose of performance improvements such as efficiency, power and torque densities, cost and so forth. The configuration and the arrangement of all coils are examined to increase their filling factor for reducing copper losses. Moreover, thinner electromagnetic steel and permanent magnets with high remanent flux density are employed to achieve higher efficiency. Experimental tests using a prototype of HEFSM validate the design results.

The nonlinearity of the inductor affects the stability of the system and the bandwidth of the controller. This paper proposes a linearized method for linearizing the nonlinear inductor in the αβ- frame under given load condition. A current controller design method is also proposed in this paper to adapt the equivalent inductance change. The equivalent inductance of a nonlinear inductor depends on the peak current flowing through the inductor in the αβ-frame but dissociates to the power factor of the output current. Simulation results and experiment results verify the theoretical derivation.

This paper presents the equivalent series resistance (ESR) modeling method of filter components and its stability impact of LCL filtered grid-connected voltage-source converters (VSCs). First, the time-domain models of filter inductor and capacitor are developed for modeling the ESR effect, which are used in simulations. Then, the current control loop gains of the grid-connected three-phase VSC, which include the ideal LCL filter and the ESR-modeled LCL filter are compared. The result shows that the ESR affects both the resonance peak and the phase characteristic in the frequency domain. Finally, in order to verify accuracy of proposed model, the loop gain is measured by network analyzer in the experimental set up, which shows that the analytical loop gain with proposed ESR modeled inductor agrees very well with experimental value. This verification means that the ESR modeling method is useful for an accurate stability analysis.