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Background: Dental professionals have so many opportunities to use injection needles and sharp instruments during dental treatment that they face an increased risk of needlestick injuries. This retrospective study reports the utilization and clinical outcomes of occupational post-exposure prophylaxis (PEP) with anti-retroviral agents after being potentially exposed to HIV at dental departments of Hiroshima University Hospital. Objective: This study reports the utilization and clinical outcomes of occupational post-exposure prophylaxis (PEP) with anti-retroviral agents after being potentially exposed to HIV at dental departments of Hiroshima University Hospital. Methods: Data on the clinical status of HIV-infected source patients and information on HIV-exposed dental professionals from 2007 to 2018 were collected. Results: Five dentists with an average experience of 5.6 years (1-15 years) were exposed. The averaged CD4-positive cell number and HIV-RNA load were 1176 (768-1898) / l and less than 20 copies/ml, respectively, in all the patients. Two of the five HIV exposed dentists received PEP. Three months after the exposures, all of their results were negative in HIV antibody/antigen tests. Conclusion: These data might support the concept of “undetectable equals untransmittable”, although HIV exposure in this study was not through sexual transmission.

Study question Was embryonic development affected by the degree of perivitelline space (PS) at the pronuclear stage in human zygotes? Summary answer Zygotes with a fully surrounding PS showed less cytoplasmic fragmentation and a higher blastocyst development rate (BDR) than zygotes with a partially surrounding PS. What is known already We previously used abnormally-fertilized oocytes (zygotes with three pronuclei; 3PN), donated by ART patients in our clinic who gave written consent for the research. The zona pellucida (ZP) was artificially removed from these oocytes at the pronuclear stage, termed ZP-free culture. The resultant ZP-free 3PN embryos showed less cytoplasmic fragmentation and a higher rate of good-quality embryos (GQE) compared with ZP-intact embryos. Furthermore, in our clinical setting, the rate of GQE and BDR of normally-fertilized embryos were clearly improved by ZP-free culture in patients with recurrent failure of ART treatments due to severe cytoplasmic fragmentation at the early cleavage stage. Study design, size, duration This study included 49 patients who gave written informed consent for our study and were treated with ART in our clinic between March and December 2020. Embryonic development was compared between zygotes with a fully surrounding PS [PS(+)] with those with a partially surrounding PS [PS(-)] at the pronuclear stage. Furthermore, the ZP of PS(-) embryos were artificially removed at the pronuclear stage, and the rate of GQE and BDR were compared with ZP-intact embryos. Participants/materials, setting, methods The degree of PS in 128 zygotes was confirmed by hypertonic preparation using 0.125M sucrose-containing HEPES medium. PS(+) and PS(-) embryos were both cultured as ZP-intact, and the rate of GQE was compared. Furthermore, 223 zygotes were divided into three groups: 1) PS(-)/ZP-intact, 2) PS(-)/ZP-free, and 3) PS(+)/ZP-intact, and cultured in an incubator equipped with time-lapse monitoring up to Day 7, and the rate of GQE, BDR and useable embryos were compared between each groups. Main results and the role of chance The degree of PS was confirmed by a hypertonic preparation (shrinkage of the ooplasm) in 128 normally-fertilized zygotes obtained from 44 cases. There were 86 PS(-) (67.2%) and 42 PS(+) (32.8%) zygotes. The mean maternal age was 35.9 in PS(-) and 40.5 in PS(+) (P Limitations, reasons for caution Although the artificial removal of ZP at the pronuclear stage (ZP-free culture) clearly increased the rate of GQE, embryonic development was not improved in all cases. It seems that this procedure is only effective in embryos with a viable ooplasm. Wider implications of the findings: The degree of PS at the pronuclear stage affects subsequent embryonic development in human zygotes. The artificial removal of ZP at the pronuclear stage (ZP-free culture) helps to suppress fragmentation and leads to an increase in GQE and BDR, and eventually, improves pregnancy rate in cases with severe fragmentation. Trial registration number non

Study question Can a novel embryo culture method that artificially removes the ZP at the pronuclear stage yield successful pregnancy in patients with poor-quality embryos and/or blastocysts? Summary answer A blastocyst transfer after ZP-free culture can result in pregnancy for patients who cannot obtain good quality blastocysts from conventional culture methods. What is known already Perivitelline threads are been associated with the formation of cytoplasmic fragments. We had previously observed perivitelline threads in the adhesive region between the ooplasm and the ZP at the first cleavage in human embryos. We removed the ZP at the pronuclear stage in 71 abnormally fertilized oocytes (zygotes with three pronuclei), donated after conventional IVF (c-IVF), and termed them ZP-free 3PN. We found ZP-free 3PN embryos could be cultured without losing blastomere adhesions. Furthermore, the rate of good quality embryos was significantly higher in ZP-free 3PN embryos compared with ZP-intact embryos (ZP-intact 2PN/2PB and 3PN embryos; P Study design, size, duration This study was conducted in two cases selected among patients who underwent ART treatment in our clinic between 2018 and 2019. Cases were selected if they lacked good quality blastocysts in previous c-IVF/Intracytoplasmic Sperm Injection (ICSI) cycles due to massive cytoplasmic fragmentation at the first and second cleavage. We performed a clinical trial of ZP-free culture from December 2019 to March 2020. Participants/materials, setting, methods Two cases were selected for this trial. Normally fertilized oocytes were grouped as ZP-free or ZP-intact. For the ZP-free group, 2PN embryos were placed in 0.125M sucrose-containing HEPES to reduce ooplasm size, then ooplasms were completely separated from ZPs by a laser and pipetting. ZP-free and ZP-intact embryos were cultured with time-lapse imaging for up to seven days. Resultant blastocysts were either transferred into uterus or cryopreserved on Day5/6/7 for future embryo transfer cycles. Main results and the role of chance The ZP-free culture method was applied to two patients (patient A and B) with recurrent failure of ART in our clinic due to poor-quality embryos and/or difficulties in obtaining good quality blastocysts. In both cases, blastocysts were successfully obtained and cryopreserved for all ZP-free culture cycles. In patient A, one good quality ZP-free blastocyst was freshly transferred five days after oocyte retrieval, and a live male baby (2925g) was delivered at 40 weeks of gestation by caesarean section). In patient B, a frozen/thawed ZP-free blastocyst transfer was conducted, and a live female baby (3225g) was delivered at 39 weeks of gestation by vaginal delivery. This shows ZP-free culturing may help obtain viable embryos in patients for which conventional in vitro culturing methods result in embryos characterized with severe cytoplasmic fragmentation and poor quality in the early cleavage stage. Limitations, reasons for caution Although successful pregnancies and deliveries were confirmed in two cases, postnatal evaluations will be absolutely necessary for infants derived from ZP-free culture. In addition, the number of trial cases needs to be expanded, however careful selection of suitable patients is necessary for this novel culture method. Wider implications of the findings: We found removing the ZP at the pronuclear stage improved embryo development and led to successful pregnancies and deliveries after blastocyst transfer. This indicates ZP-free culturing may be an effective method for decreasing cytoplasmic fragmentation caused by perivitelline threads or adhesion between the ooplasm and the zona pellucida. Trial registration number Not applicable

Study question Does the direction of formation for the first cleavage plane relative to the pronuclear axis affect clinical outcome? Summary answer A first cleavage division perpendicular to the pronuclear axis adversely affects the rate of embryo utilization for transfer or cryopreservation and the pregnancy outcome. What is known already It remains unclear how the first cleavage plane is determined in human embryos. By using time-lapse monitoring, our previous study (presented in ESHRE 2019) suggested that both the axis and locations of male and female pronuclei are involved in determining the first embryonic cleavage plane. Furthermore, by using immunofluorescence analysis, it was also revealed that most analyzed zygotes showed two pericentrin signals aligned around the interface between the male and female pronuclei. Our findings suggest that the pronuclear axis strongly influences the positions of the centrosomes, which become mitotic spindle poles and define the first cleavage plane. Study design, size, duration: From January 2015 to December 2017, time-lapse imaging (EmbryoScope®) of 3397 intracytoplasmic sperm injection (ICSI) oocytes was conducted. Of those, the relationship between the pronuclear axis and the first cleavage plane was analyzed in 607 normally fertilized embryos that cleaved to two cells and were obtained in 2015. Furthermore, of 3397 ICSI oocytes, 749 transferred embryos were classified based on the first cleavage patterns relative to the pronuclear axis, and the pregnancy rate was examined. Participants/materials, setting, methods A straight line connecting the centers of the pronuclei was defined as the 2PN axis. Based on the direction of the first cleavage relative to the 2PN axis, embryos were classified into three groups: parallel, perpendicular and intermediate. Fresh embryos were transferred on Day 2/3 (fresh-ET). Frozen and thawed embryos were transferred on Day 2/3 or Day 5 (F/T-ET). Clinical pregnancy was defined as confirmed gestational sac in the uterine cavity. Main results and the role of chance Of 607 analyzed embryos, 506 produced suitable images and were assigned to one of three groups: parallel (84.4%, n = 427), perpendicular (9.7%, n = 49) and intermediate (5.9%, n = 30). Embryos that formed a cleavage furrow parallel to the 2PN axis were significantly more frequent than others (perpendicular, intermediate) (P Limitations, reasons for caution Since only ICSI embryos were analyzed in this study, the influence of fertilization methods on subsequent development could not be investigated. Further studies including preimplantation genetic testing for aneuploidy may help determine the reasons why pregnancy rates differ between groups. Wider implications of the findings: We suggest that the 2PN axis is essential for determining the first cleavage plane because it seems to be involved in positioning the mitotic spindle poles. The direction of the first cleavage plane relative to the 2PN axis can be an important indicator for predicting embryo development and pregnancy outcome Trial registration number none

The aim of the study was to evaluate the oral environment and the taste function of Japanese HIV-infected patients treated with antiretroviral therapy. Their median age of 73 patients taking anti-HIV drugs was 46 years. The median period of taking anti-HIV drugs was 30 months. The oral condition was evaluated by measurement of oral moisture, amount of saliva secretion, the number of oral bacteria, presence of oral candida, a taste test, and the number of missing teeth. The levels of oral moisture and secreted saliva were significantly lower in the HIV-infected group than in the healthy volunteer (control) group. The HIV-infected group showed a more robust decrease in taste sensation than the control group. The number of missing teeth was significantly higher in the HIV-infected group than in the control group. Furthermore, all of the evaluated oral conditions were worse in the HIV-infected patients whose CD4+ T lymphocyte counts were less than 500/mm

Electric vehicles (EV) offer promise as an effective solution to environmental problems. One of the keys to their successful diffusion is the provision of adequate battery charging infrastructure. In order to create a charging infrastructure by installing equipment in such as locations as carports in private homes, the wireless battery charging system is very suitable. EVs can be used in smart house systems to supplement the energy storage. This vehicle to home (V2H) system essentially requires a bidirectional power transfer feature between the EV and home. This paper presents a new bidirectional inductive power transfer (IPT) system for wireless V2H with simplest components and low cost aiming at wide diffusion for home use. Proposed is a novel type of bidirectional wireless EV charging system with an efficient and compact type single-ended quasi-resonant high-frequency inverter for V2H.

This paper is aimed at presenting a novel system topology and control scheme of a selective dual-mode pulse-modulated high-efficiency single-phase sinewave power-conversion circuit for the new energy generation and storage applications. This power-conversion system is composed of a time-sharing-operated sinewave-absolute-modulation boost chopper with a bypass diode in the first power conditioning and processing stage and time-sharing sinewave partially pulse-modulated full-bridge inverter in the second stage. The proposed power conditioner is operated by a selective time-sharing dual-mode pulse pattern signal processing control scheme without electrolytic capacitor dc link. The unique operating principle of the two-power conditioning and processing stages with sectional time-sharing dual-mode partial sinewave-modulation scheme is described and discussed with a design example. In addition, this paper proposes also a sinewave tracking voltage controlled soft switching pulsewidth-modulation boost chopper with a bypass-diode loop, which includes a passive auxiliary edge-resonant snubber. The new conceptual operating principle and the control implementation of this novel power conditioner are presented and evaluated through experimental and simulation results

Functionality of natural fibre-reinforced composites continually attracts attention and offers a unique possibility. We fabricated several types of unidirectional and random bamboo fibre green composites, and examined their damping properties as a function of bamboo fibre content, fibre length, and fibre morphology. The loss factors of the bamboo fibre green composites decreased with increasing bamboo fibre content. However, the loss factors gradually decreased in the composites reinforced with fibre content higher than 40 mass%. The loss factors of random short fibre (10mm) reinforced green composites were higher than those of unidirectional ones. It can be seen that the damping factor of bamboo fibre green composites depended on fibre length and fibre content, and that vibration damping properties of the bamboo green composites were better than those of glass fibre reinforced plastics.

RESUMO O ácaro Oligonychus ilicis apresenta ampla distribuição no Estado de São Paulo, com maiores incidências nos períodos mais secos do ano. Estes ácaros possuem o hábito de estarem presentes na página superior das folhas do cafeeiro. Foram avaliados no controle deste ácaro, extratos aquosos, etanólicos e hexânicos de Lavandula angustifolia Mill., Dahlia pinnata Cav., Solanum paniculatum L., Agave angustifolia Haw, Ocimum basilicum L., Solanum melongena L., Rhododendron simsii Planch., Ficus elastica Roxb, Codiaeum variegatum (L.) Bl., Spondias purpurea L., Sonchus oleraceus L., Ruta graveolens L., Annona squamosa L., Pennisetum purpureum Schumach., Dieffenbachia brasiliensis (Veiech) e Allamanda cathartica L. Discos foliares de café var. Mundo Novo foram mergulhados na solução de extrato por 5seg e as fêmeas adultas em número de 20 por parcela confinadas na superfície do disco e mantidas em câmara incubadora a 25 ± 2º C e 70 ± 10% UR. Avaliação de mortalidade foi realizada com 48h. Os melhores resultados em eficiência foram obtidos com os extratos etanólico e hexânico de Dieffenbachia brasiliensis (56 e 52%), D. pinnata (54%), Allamanda cathartica (44%) e S. paniculatum (46 e 48%).

Electric vehicles (EV) offer promise as an effective solution to environmental problems. One of the keys to their successful diffusion is the provision of adequate battery charging infrastructure. In order to create a charging infrastructure by installing equipment in such as locations as carports in private homes, the wireless battery charging system is very suitable. EVs can be used in smart house systems to supplement the energy storage. This vehicle to home (V2H) system essentially requires a bidirectional power transfer feature between the EV and home. This paper presents a new bidirectional inductive power transfer (IPT) system for wireless V2H with simplest components and low cost aiming at wide diffusion for home use. Proposed is a novel type of bidirectional wireless EV charging system with an efficient and compact type single-ended quasi-resonant high-frequency inverter for V2H.

A novel controller for generic servo systems using a neural network input-output measurement classifier and a staggered proportional plus integral plus derivative-like gain control scheme is proposed. The controller incorporates a knowledge-based control strategy and does not require a priori knowledge of the plant. The system controller is robust to both structured and unstructured uncertainties.

This paper presents an advanced method to improve the speed response characteristics of an AC servomotor drive system with mechanically resonant loads without any data-based experiences. Mechanical resonance and antiresonance are both effectively suppressed on the basis of a load speed feedback approach for the AC servo motion system. A novel /spl alpha/-parameter ultimate sensitivity method is applied to obtain a stable compensation between the proportional plus integral controller gains and load speed feedback gain. The fuzzy reasoning processing for this system is introduced for autotuning of the /spl alpha/ parameter. The effectiveness of the proposed autotuning control scheme in the AC speed servo system is verified in terms of computer simulation results.

The paper deals with an advanced control method of system gain parameter autotuning implementation for DC brushless servo drive system, which is based on a fuzzy reasoning logic with an automatically processed learning control strategy. In the learning operation, fuzzy rules are generated automatically so as to be suitable for unknown mechanical load which is linked to a servo motor shaft and memorised in a database. As a result, the performance in gain parameter autotuning scheme is improved in accordance with increasing the number of learning operations. The feasibility effectiveness of the practical application for this autotuning procedure in DC brushless servo drive systems is confirmed on the basis of experimental results.

A variety of ultrasonic motors (USMs) have attracted special interest as a new type of actuator in servo motion control systems. For practical applications, the speed servo control system incorporating the ultrasonic motor developed in Japan has some special unique features. However, this system has several significant problems, such as the inherent speed ripple characteristics, the speed regulation characteristics under the condition of applied disturbance load torque, and the speed tracking characteristics. In order to solve these practical problems, some control schemes of ultrasonic-actuated motor systems have been proposed and discussed theoretically, which include fuzzy reasoning control, adaptive control, repetitive learning control, and neural-network-based learning control. However, it is considered that these control strategies mentioned above have not been sufficiently substantiated from a feasible experimental point of view. This paper presents a newly proposed precise speed tracking servo control system using the compact traveling-wave-type ultrasonic motor. Its proposed control scheme is composed of both the driving frequency control loop with the variable-gain strategy and the applied voltage control loop with the speed ripple reduction strategy of the USM. The improved speed characteristics realized by this proposed control system are demonstrated and evaluated in experiments.

A practical 1.3 /spl mu/m optical fiber amplifier with reliable 1.01-/spl mu/m band laser diode pump light sources and an efficient praseodymium-doped In/Ga-based fluoride fiber is presented. A praseodymium-doped In/Ga-based fluoride fiber is characterized using measurable parameters, and amplified characteristics are theoretically analyzed. Signal output power of +16.2 dBm (42 mW) is achieved for an amplifier pumped by four 1.01-/spl mu/m band laser diodes. By using the amplifier as a power booster, data of 2.5 Gb/s is successfully transmitted more than 100 km.

An LLC multi-resonant DC-DC converter with anti-resonant tank is presented in this paper. The five-element multi-resonant (LLC-LC) dc-dc converter can realize the wide range regulations of output voltage and power by pulse frequency modulation (PFM) under soft switching conditions. The resonant dc-dc converter proposed herein is suitable for renewable and sustainable energy applications such as battery chargers interfaced with a photovoltaic power generation system. In this paper, the design guideline of circuit parameters is originally described. Experiment results on the soft-switching performances and steady-state characteristics including the power loss analysis are demonstrated, thereby the effectiveness is verified from a practical point of view.

1. The structures of major biliary and urinary metabolites of ecabapide in rat were identified by comparison with authentic standards using lc-ms and 1H-nmr spectrometry. 2. A major metabolite was found in the bile obtained from rat after an oral dose of 14C-ecabapide and identified as the amidaldehyde derivative. In the urine, two polar metabolites were characterized as the phenolic sulphates. Further, two lipophilic metabolites were identified as alcohol derivatives, and two others as oxamic acids. 3. From these results, it was estimated that the first step in the metabolism of ecabapide in rat was oxidative N-dealkylation to produce the amidaldehyde. This amidaldehyde was further metabolized by two routes, one by reduction of the amidaldehyde into the corresponding alcohol followed by mono-demethylation and subsequent aromatic O-sulphation, the second by oxidation of the amidaldehyde into the oxamic acid followed by mono-demethylation and subsequent aromatic O-sulphation.

1. After oral administration of 14C-semotiadil fumarate to rat, 81.3% of the dosed radioactivity was excreted into the bile.2. Five major biliary metabolites were detected and characterized as phenolic O-glucuronides by FAB mass spectrometry and 1H-nmr spectrometry.3. From these results it was concluded that the first step in the metabolism of semotiadil in rat was oxidations at various portions around the molecule to produce phenols. These oxidations implied the ring-opening of the methylenedioxy ring, O-demethylation of the methoxybenzene, hydroxylation of the ring, and aromatic N-demethylation. The next step was O-glucuronidation of the resulting intermediate phenolic metabolites.

This paper deals with a cost effective IPT wireless EV battery charger for smart house, which incorporates the simplest quasi -resonant soft switching pulse modulated inverter using the latest SiC-MOSFET into high-frequency isolated DC-DC converter.

Electric Vehicles (EV) offer promise as an effective solution to environmental issues. One of the key technologies to their successful diffusion is the provision of adequate battery/capacitor charging infrastructure. In order to create a charging infrastructure by installing equipment in such as locations as carports in private homes, the inductive power transfer (IPT)-wireless battery charging system is very suitable. It is a promising system for wider diffusion because it is easy and safe to use for a broad range of users including the elderly. This paper presents a new system with the simplest components and low cost aiming at wide diffusion for home use. Proposed is a novel type of IPT-wireless EV charging system with an efficient and compact type single-ended load-resonant high-frequency inverter and DC-DC converter using SiCMOSFET. The single-ended high-frequency resonant inverter, which can operate under a self-excited ZVS control and a PFM power regulation scheme is evaluated from an experimental point of view. This system can supply a controlled charging current successfully with simple output stage. A feasibility study result is presented as a charging system for the commuter EV to demonstrate the viability of the proposed system.

In this paper, a novel grid integration system for a variable-speed wind turbine using Interior Permanent Magnet Synchronous Generator (IPMSG) is developed. The power-conditioner system(PCS) consists of a series-type 12-pulse diode rectifier powered by a phase shifting transformer and then cascaded to a PWM voltage source inverter. The series-type 12-pulse diode rectifier of the generator-side converter can work without any control, while the q-axis active current of the grid-side PWM inverter is only controlled to follow the optimized active current reference. The optimal active current reference is determined by using a simple MPPT algorithm which requires only three sensors in order to track the maximum power of the wind turbine. The losses in the IPMSG can be effectively reduced by setting a passive filter at the generator terminals. The laboratory results indicate that the proposed construction and scheme are simple, cheep and efficient.

SiC-SIT power semiconductor switching devices has an advantage that its switching time is high speed compared to those of other power semiconductor switching devices. We adopt newly developed SiC-SITs which have the maximum ratings 800V/4A and prepare a breadboard of a conventional single-ended push-pull(SEPP) high frequency inverter. This paper describes the characteristics of SiC-SIT on the basis of the experimental results of the breadboard. Its operational frequencies are varied at from 100 kHz to 250kHz with PWM control technique for output power regulation. Its load is induction fluid heating systems for super-heated-steam production.

We have constructed a fast atomic-beam collinear laser spectroscopy system connected to the on-line isotope separator facility GARIS/IGISOL at RIKEN. This system is potentially powerful in studying refractory elements. To test the system, an off-line collinear experiment was made on stable Hf isotopes produced by means of laser ablation technique. For production of radioactive Hf isotopes, the use of the inverse kinematics of a fusion reaction,9Be(166Er,xn)175-xHf, was investigated. The radioactive isotope169Hf was successfully extracted from GARIS/IGISOL and accelerated up to 30 keV.

The velocity distribution of an ion beam from an IGISOL ion guide isotope separator on-line was measured directly by means of laser spectroscopy and compared with that estimated from the mass spectrum. The latter is found to be more than two times broader than the former. The emittance of the ion beam as well as its velocity spread was also studied with laser beams. It is noted that the emittance affects the mass spectrum considerably, resulting in a poor resolving power for the net velocity spread. Laser spectroscopy of radioactive atoms with the IGISOL, especially of refractory elements, seems promising.

A direct measurement of the velocity distribution of ion beams from an ion-guide isotope separator on-line (IGISOL) was carried out at RIKEN with a technique of laser spectroscopy. The skimmer-potential and gas-cell pressure dependence of the velocity distribution were also measured. The velocity distribution was found to be about two times narrower than that estimated from the mass resolving power (MRP). It is pointed out that the velocity spread deduced from MRP is considerably overestimated at various conditions. The way of improvement to make the velocity distribution of the ion beam from the IGISOL narrower and the feasibility of fast atomic-beam collinear laser spectroscopy are discussed.

This paper presents a high-efficiency one stage ZVS-PWM resonant single-ended push-pull (SEPP) high frequency inverter with new PFC functional scheme. This high-frequency resonant power converter with lossless snubbing capacitors which is composed of a passive PFC converter operating at one diode conducting full bridge circuit mode consists of asymmetrical ZVS-PWM high frequency inverter with non-bulky electrolytic capacitor stage for DC boosted voltage smoothing and induction heated load with tuned capacitor, and boost inductor between HFAC side and mid point of. The periodic steady-state operating principle of one stage high frequency series load resonant inverter with lossless capacitor is described by using the switching mode equivalent circuits in addition to the simulated operating voltage and current waveforms. The operating performances of this high-frequency ZVS-PWM resonant inverter with lossless snubbing capacitors are also illustrated on the basis of simulation analysis, which includes its UFAC-to-HFAC power regulation characteristics, soft switching operating range, UFAC side power factor characteristics and line current harmonics characteristics by FFT analysis. In principle, the effectiveness of this UFAC-to-HFAC direct power frequency converter designed for consumer high-frequency III appliances is evaluated and proved on the basis of simulation results.

A newly-developed zero current soft-switching (ZCS)-PWM cell-assisted asymmetrical half-bridge (AHB) DC-DC converter topology with a high frequency (HF) link is presented in this paper. The soft-switching half-bridge DC-DC converter consists of a PWM-controlled single-ended half-bridge HF inverter and a center-tapped rectifier linked by a HF transformer. In order to attain the wide range of ZCS commutation in the primary-side HF inverter, the active edge resonant snubber cell composed of a switched capacitor and a lossless inductor is adopted in the half-bridge leg, providing ZCS commutation for a wide range of output power under constant switching frequency. The operation characteristics of the proposed DC-DC converter are described, and its feasibility data is demonstrated and evaluated with simulation and experimental results.

This paper presents a single ended push-pull (SEPP) high frequency inverter incorporating a reverse blocking active auxiliary quasi-resonant circuit using bipolar mode static induction transistors (BSITs) as active switches. This inverter can realize soft switching of the active switches over wider output power regulation range compared with the conventional SEPP inverter. It is performed by incorporating an auxiliary active switch to the conventional SEPP inverter to feed a required current for the soft switching operation of the main switches. The current fed to the main switches during their short switching period assists their soft switching operation over wide output power regulation range. The detailed evaluation of its operational principle and characteristics is carried out with the aid of computer aided simulation and the experimental result obtained by a bread board.

This paper deals with a novel type soft switching utility frequency AC-high frequency AC converter using asymmetrical PWM bidirectional active switches which can be defined as high frequency resonant matrix converter. This power frequency changer can directly convert utility frequency AC power to high frequency AC power ranging more than 20 kHz up to 100 kHz. Only one active edge resonant capacitor-assisted soft switching high frequency load resonant cyclo-converter is based on asymmetrical duty cycle PWM strategy. This high frequency cyclo-converter uses bidirectional IGBTs composed of anti-parallel one-chip reverse blocking IGBTs. This high frequency cyclo-converter has some remarkable features as electrolytic capacitorless DC busline link, unity power factor correction and sinewave line current shaping, simple configuration with minimum circuit components and low cost, high efficiency and downsizing. This series load resonant cyclo- converter incorporating bidirectional active power switches is developed and implemented for high efficiency consumer induction heated food cooking appliances. Its operating principle is described by using equivalent circuits. Its operating performances as soft switching operating ranges and high frequency effective power regulation characteristics are discussed on the basis of simulation and experimental results.

A novel zero current soft-switching (ZCS)-PWM cell-assisted asymmetrical half-bridge (AHB) DC-DC converter topology with a high frequency (HF) link is proposed in this paper. The newly-proposed DC-DC converter consists of a PWM-controlled single-ended half-bridge HF inverter and a center-tapped rectifier linked with a HF transformer. In order to attain the wide range of ZCS commutation in the primary-side HF inverter, the active edge resonant snubber cell composed of a switched capacitor and a lossless inductor is adopted in the half-bridge leg, providing ZCS commutation for a wide range of output power under fixed (constant) switching frequency. The operation characteristics of the DC-DC converter proposed here are described, and its feasibility data is demonstrated and evaluated with simulation and experimental results.

This paper presents a utility frequency AC (UFAC) to high frequency AC (HFAC) direct power frequency conversion pulse modulated conditioning circuit using bidirectional power switches. This power converter can efficiently operate under a principle of active zero voltage clamped soft commutation for consumer induction heating (IH) fixing roller for copy machine and printer. This HFAC direct power frequency converter defined as resonant high frequency PWM controlled power frequency converter using bidirectional switches is developed and evaluated in this paper for consumer IH fixing heat roller using industrial HFAC power supply. Its operating principle is described on the basis of switching mode equivalent circuits during switching one cycle period. It is evaluated on the basis of its simulation and experimental results on the performances of HFAC direct power frequency converter treated here including various duty factor control variable vs. HFAC power regulation characteristics as well as zero voltage soft switching ranges.

This paper presents a new circuit topology of active edge resonant snubbers-assisted soft switching symmetrical PWM inverter type DC-DC high power converter with a high frequency planar transformer. Its operating principle is described by using switching mode equivalent circuits, together with its unique features. The performance evaluations of its experimental setup are actually illustrated on the basis of the power loss analysis. The practical effectiveness of new DC-DC converter treated here is proved for low voltage and large current DC output implementation. The extended circuit topologies of DC-DC converter treated here are also demonstrated and discussed in this paper.

This paper presents a utility frequency AC (UFAC) to high frequency AC (HFAC) direct power frequency conversion pulse modulated conditioning circuit using bidirectional power switches. This power converter can efficiently operate under a principle of active zero voltage clamped soft commutation for consumer induction heating (IH) fixing roller for copy machine and printer. This HFAC direct power frequency converter defined as resonant high frequency PWM controlled power frequency converter using bidirectional switches is developed and evaluated in this paper for consumer IH fixing heat roller using industrial HFAC power supply. Its operating principle is described on the basis of switching mode equivalent circuits during switching one cycle period. It is evaluated on the basis of its simulation and experimental results on the performances of HFAC direct power frequency converter treated here including various duty factor control variable vs. HFAC power regulation characteristics as well as zero voltage soft switching ranges.

This paper deals with a novel type soft switching utility frequency AC- high frequency AC converter using asymmetrical PWM bidirectional active switches which can be defined as high frequency resonant matrix converter. This power frequency changer can directly convert utility frequency AC power to high frequency AC power ranging more than 20 kHz up to 100 kHz. Only one active edge resonant capacitor-assisted soft switching high frequency load resonant cyclo-converter is based on asymmetrical duty cycle PWM strategy. This high frequency cyclo-converter uses bidirectional IGBTs composed of anti-parallel one-chip reverse blocking IGBTs. This high frequency cyclo-converter has some remarkable features as electrolytic capacitorless DC busline link, unity power factor correction and sinewave line current shaping, simple configuration with minimum circuit components and low cost, high efficiency and downsizing. This series load resonant cyclo-converter incorporating bidirectional active power switches is developed and implemented for high efficiency consumer induction heated food cooking appliances. Its operating principle is described by using equivalent circuits. Its operating performances as soft switching operating ranges and high frequency effective power regulation characteristics are discussed on the basis of simulation and experimental results.

This paper present an improved circuit topology for a buck chopper type single phase PFC-AC/DC converter with active power filtering function, which has smaller in reactor size and lighter in its weight, and can minimize the DC output voltage ripple factor. In addition, this active PFC-AC/DC converter can be also suppressed the current harmonics in utility AC grid without any specific feedback control scheme with current sensor interface. The circuit configuration treated here is more suitable for a variety of emergency power as well as telecommunication supply, where the lightning resistance is particularly considered to be more effective for 48 V-10 A output specification. In this paper, the operating principle of proposed AC-DC converter circuit using power MOSFETs and its related control implementation are described, along with its simulation and experimental results and their evaluations. The extended PFC-AC/DC converter topologies are demonstrated, which are operating at the proposed control scheme.

1. The kinetic activity of UDP-glucuronosyltransferases (UDPGT) towards a dithiol metabolite of malotilate, 2,2-di(isopropoxycarbonyl)ethylene-1,1-dithiol, was investigated using rat and rabbit hepatic microsomes. The thio-glucuronide formed was analysed by h.p.l.c. The Km values obtained using rat and rabbit UDPGT were 36.3 +/- 3.3 and 443 +/- 43 microM, respectively. The Vmax values were 7.14 +/- 0.61 and 29.2 +/- 6.4 nmol/min per mg (mean +/- SD, n = 3). 2. Phenobarbital, an inducer of the GT2 isoform of UDPGT, increased rat microsomal UDPGT activity towards the dithiol. In inhibitory studies, menthol and borneol (specific substrates for GT2a isoform) competitively inhibited glucuronidation of the dithiol. Thus it was concluded that formation of the thio-glucuronide was catalysed mainly by the GT2a isozyme of UDPGT, which is involved in glucuronidation of monoterpenoid alcohols.

The oscillation voltage (Ebm) is an important parameter of the characteristic constant of a high power microwave generator. When Ebm could be made high, it serves so as to improve the power conversion efficiency of a magnetron. Thus, the newly developed magnetron with 7% higher oscillation cut-off voltage than the present conventional one is manufactured by Matsushita Electric Industrial Co.Ltd. In addition to this, the utility AC power line current reduced harmonic type direct inverter AC-DC power converter suitable and acceptable for driving this magnetron is proposed in this paper. This direct high frequency inverter type soft switching PWM AC-DC converter has the voltage-boost function based on active clamp scheme with soft switching pulse modulation strategy topology. This paper describes a novel type active clamp AC-DC power converter circuit defined as direct high frequency inverter and the switching operation of this power converter is described and discussed on the basis of simulation and experimental results. The operating characteristics of this soft switching direct high frequency inverter type AC-DC power converter using IGBTs that incorporates the harmonic current improvement as well as power factor correction are evaluated and discussed from a practical point of view as compared with the conventional AC-DC power converter.

This paper presents a novel phase shifted ZVS-PWM high frequency load resonant inverter for electromagnetic induction fluid heating (IH) appliances. The proposed high frequency inverter can be achieved stable and efficient zero voltage soft commutation over a widely specified power regulation range from full power to low power by using an active auxiliary quasi resonant snubber. The steady state operating performance of this inverter is evaluated and discussed on the basis of simulation and experimental results for IH dual-packs heater (DPH) of compact fluid heating appliance. Finally, the effectiveness of IH application of the proposed high frequency inverter with auxiliary active quasi-resonant snubber is demonstrated from the practical point of view.

This paper presents two new circuit topologies of voltage source-fed soft-switching PWM inverter using a high frequency transformer parasitic inductive components with full- bridge or half-bridge configuration, which are more suitable for utility AC 400 V-rms input mains. These circuits have each reverse conducting power semiconductor switching devices in series with high and low DC buslines, a single or two lossless snubbing capacitors in parallel with two DC buslines and additional diode components. Under the newly proposed high frequency softswitching PWM inverter link DC-DC power converter circuits for utility AC 400V-rms input, all the active power switches in the full- bridge arms or half-bridge arm and DC buslines achieve ZCS turn- on commutation operation and ZVS turn-off commutation operation, and consequently the total turn-off switching power losses can be significantly reduced. As a result, a high switching frequency for IGBTs used can be actually realized at a frequency band more than about 20 kHz. It is proved that the more the switching frequency of inverter increases, the more soft switching PWM DC-DC converters with a high frequency transformer have remarkable advantages for its power conversion efficiency and power density as compared with the conventional hard switching PWM full-bridge inverter type DC-DC converter. The practical effectiveness of these new converter topologies are confirmed for low voltage and large current DC power supplies as high performance arc welding machine from a practical point of view.

In this paper, a novel type of auxiliary active snubbing circuit assisted edge-resonant soft--switching pulse width modulation (PWM) inverter is proposed for consumer induction heating equipments. The operating principle of this high frequency inverter is described using switching modes and equivalent circuits. This newly developed series resonant high frequency inverter can regulate its high frequency output AC power under a principle of constant frequency active edge resonant soft-switching commutation by asymmetrical PWM control system. The high frequency power regulation and actual power conversion efficiency characteristics of consumer induction heating (IH) products using the proposed soft-switching PWM series load resonant high frequency inverter evaluated. The practical effectiveness and operating performance of high frequency inverter are discussion on the basis of simulation and experimental results as compared with the conventional soft-switching high frequency inverter.

This paper presents a novel dynamic model in the stationary reference frame for a diode bridge rectifier with a DC-link filter directly connected to a three-phase induction generator (IG). Moreover, a hybrid excitation system, consisting of a capacitor bank and an active power filter (APF), provides the pure sinusoidal currents needed to excite and control the stand-alone IG system's output voltages. A deadbeat current control strategy for the APF is used to enhance the operating performances of the stand-alone IG and reduce the size of the APF. This power generating system can be used for small hydro and wind rural applications where its generated electrical power is supplied to DC and AC loads. The measurement results validate the proposed power generating system with the deadbeat current controller as a good application for the IG to reduce the total system cost and the required number of sensors

This paper presents a new circuit topology of dc bus line switch-assisted half-bridge soft switching PWM inverter type dc-dc converter for arc welder. The proposed power converter is composed of typical voltage source half-bridge high frequency PWM inverter with a high frequency transformer link in addition to dc bus line side power semiconductor switching devices for PWM control scheme and capacitive lossless snubbers. All the active power switches in the half-bridge arm and dc bus lines can achieve ZCS turn-on and ZVS turn-off commutation operation and consequently the total turn-off switching losses can be significantly reduced. As a result, a high switching frequency of using IGBTs can be actually selected more than about 20 kHz.

B-SIT has an advantage that its on-resistance is extremely low compared to those of other power semiconductor switching devices. Accordingly, we can suppress its conduction losses during large current operation. Then, high conversion efficiency is expected when B-SITs are utilized as the switching devices of high frequency inverters. Here, we adopt newly developed B-SITs which have the maximum ratings 150 V/50 A and prepare a breadboard of a conventional single-ended push-pull (SEPP) high frequency inverter, which has a simplified circuit constitution and relatively wide range applications. This paper describes the characteristics of B-SIT on the basis of the experimental results of the breadboard. Its operational frequency is fixed at 50 kHz with PWM control technique for output power regulation. Its load is induction fluid heating systems for super-heated-steam production

This paper presents a deadbeat current control strategy for a stand-alone induction generator (IG), working with variable speed and load to regulate both the IG terminal voltage and the dc-bus voltage of the pulse-width modulation (PWM) converter. The deadbeat current controller is a good application for the IG to reduce the total system cost and the required number of sensors. In the proposed system, not a rotary encoder but a new designed phase locked loop (PLL) circuit is used to determine the electric angle. A 2.2 kW laboratory prototype has been built to confirm the feasibility of the proposed method

In this paper, we propose a high-frequency switching pulse modulation utility-interfaced power conditioner with the flyback high-frequency transformer link and the switched-capacitor snubber cell. With the aid of the switched-capacitor resonant snubber cell, the high-frequency switching devices in the primary side of the proposed DC-to-AC power inverter can be turned-off with zero voltage soft-switching (ZVS). Moreover, the proposed power conditioner operates the currents in the discontinuous conduction mode (DCM) and takes the advantages of zero current soft-switching turn-on. Its output port is connected directly to the utility grid AC power source. At the end, the prototype of the proposed high-frequency utility-interfaced power conditioner (HF-UPC) is built and tested in the experiments. Its power conversion processing is verified and the output current is qualified in accordance with the guidelines of the power systems

This paper presents a novel boost-full bridge cascade system topology without electrolytic capacitor DC filter link and its time-sharing control scheme of a selective dual mode pulse modulated high efficiency single-phase sinewave power conversion conditioner for small scale new energy generation applications. This power conversion system is composed of a sinewave absolute value tracking boost chopper with a bypass diode in the first power stage and sinewave PWM full-bridge inverter in the second power stage operated by dual mode selective time-sharing pulse pattern signal processing control approach. The unique operating principle of two power conditioning and processing stages with sectional time-sharing dual mode partial sinewave modulation scheme is described and discussed for stand alone utilization. The paper proposes a sinewave tracking voltage controlled soft switching PWM boost chopper with a bypass diode loop, which includes a passive auxiliary edge-resonant snubber. The new conceptual operating principle of this novel sinewave pulse modulated power conditioner acceptable for small scale new energy generation is evaluated through the experimental and simulation results, together with a control implementation