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Supported Au nanoparticles modified with basic Lindqvist-type [Nb6O19]8− clusters were fabricated by a simple adsorption method and exhibited efficient reduction activity for p-nitrophenol due to the base and reduction dual functional catalysis.

A patient underwent surgical resection twice for primary and metastatic dedifferentiated liposarcomas. Computed tomography revealed a tumor mass at the cavoatrial junction. Prompt surgical resection of the tumor with thrombectomy was successfully performed using cardiopulmonary bypass with hypothermic circulatory arrest. Despite the poor prognosis of metastatic or recurrent liposarcoma, the patient has survived for 8 years since the first tumor resection.

The influence of lower limb ischemia on the loss of skeletal muscle mass, which is a prerequisite for sarcopenia, remains poorly studied in patients with peripheral artery disease (PAD). We determined whether or not lower limb ischemia correlates with a loss of skeletal muscle mass in patients with PAD.The data of 101 patients (202 legs) with PAD were retrospectively analyzed. Body composition was measured using a bioelectrical impedance analysis. Based on the Asian Working Group for Sarcopenia, low muscle mass (LMM) was defined as skeletal muscle mass index (SMI)7.00 kg/mThere were significant differences in age, ankle-brachial pressure index (ABI) per patient, and the geriatric nutritional risk index (GNRI), between patients with and without LMM. Multivariable logistic regression analysis showed age (odds ratio [OR], 1.09; p = 0.009), GNRI (OR, 0.93; p = 0.003), and ABI per patient (OR, 0.02; p = 0.027) as independent risk factors for LMM.These data show a detrimental effect of lower limb ischemia on skeletal muscle mass loss, suggesting that PAD may affect the development of secondary sarcopenia.

A patient had undergone surgical resection twice for primary and metastatic dedifferentiated liposarcomas. Follow-up computed tomography revealed a new tumor mass located at the cavoatrial junction. Prompt surgical resection of the tumor with thrombectomy was successfully performed using cardiopulmonary bypass with hypothermic circulatory arrest. We report a rare case of a patient surviving for 8 years after the first tumor resection despite the poor prognosis of metastatic or recurrent liposarcoma.

Objective: Patients of aorto-iliac aneurysms who undergo endovascular aortic repair (EVAR) require internal iliac artery (IIA) occlusion with coil embolization and its coverage with the stent graft to prevent type II endoleak after extending the endograft into the external iliac artery. However, it has become well recognized that IIA occlusion cause buttock claudication and other various sequelae due to pelvic ischemia. We retrospectively analyzed IIA occlusion outcomes. Methods: From October 2008 to February 2015, 71 patients with aorto-iliac aneurysms underwent IIA occlusion prior to EVAR. The relationship between pelvic circulation and symptom of pelvic ischemia was studied. Results: Buttock claudication occurred in 17 patients (22.9%) of all. Eight patients (14.8%) in unilateral IIA occlusion group (54 patients) and nine patients (52.9%) in bilateral IIA group (17 patients) had sequelae of claudication. The sacrifice of the communication of superior gluteal artery (SGA) and inferior gluteal artery (IGA) led to buttock claudication in 18 (64.3%) of 28 limbs. Instead, only 4 of 60 limbs had buttock claudication, when we preserved the communication between SGA and IGA. In all patients, staged treatment of aorto-iliac aneurysms with IIA occlusion and EVAR were done successfully without pelvic ischemic complications except for buttock claudication, and postoperative CT scanning showed no endoleakage. Conclusion: IIA occlusion prior to EVAR is recognized as a safe and reasonable strategy. It is emphasized that preservation of the communication of SGA and IGA is important to prevent buttock claudication. (This is a translation of Jpn J Vasc Surg 2016; 25: 240-245.).

A severely obese patient with dyspnea and weighing 197 kg presented to us. He experienced an impending paradoxical embolism in the left ventricle caused by a deep vein thrombosis passing through a patent foramen ovale, as well as an acute massive pulmonary thromboembolism. Emergency thromboembolectomy from the right atrium and the bilateral pulmonary arteries was successfully performed. This is an extremely rare case of a severely obese patient with a body mass index of 66.6 kg/m2 who required emergency cardiac surgery by a cardiopulmonary bypass.

The use of topical antimicrobials applied to the sternum during cardiac procedures in combination with intravenous agents to prevent mediastinitis has been reported to yield good results. The objective of this study is to provide optimal method of topical antimicrobials for the prevention of sternal wound infection after cardiac surgery. We retrospectively evaluated the patients undergoing adult cardiac surgery at five institutions between January 1994 and August 2013 for the incidence of deep sternal wound infection (DSWI). The patients were sprayed with a solution of cefazolin and gentamicin into the surgical site several times during surgery. The incidence of DSWI was evaluated. Four major risk factors [diabetes mellitus (DM), emergency operation, dialysis and prolonged operation] were also evaluated for their implications in the outcome with the antimicrobial spraying. Totally, 6960 patients were analyzed. The incidence of DSWI was 0.46 % in the spraying group versus 1.7 % in control group (p

Traditionally, the chief surgical indicator for human immunodeficiency virus (HIV)-infected patients was the CD4-positive T-lymphocyte count; however, there is no current consensus. Reports published after 2006 indicated that HIV-infected patients had a higher incidence of postoperative pneumonia and higher 12-month mortality rates. In addition, CD4 counts had no relation to the in-hospital outcome. Therefore, we retrospectively examined all of the previous patients who underwent operations in our department on the basis of these findings.Regardless of the initiation of highly active anti-retroviral therapy (HAART), we retrospectively reviewed 10 general thoracic surgeries performed in our department according to the CD4 cell count, HIV-ribonucleic acid (RNA) viral load, time of HAART initiation, operating time, amount of blood, postoperative course, and period of observation.There was no incidence of postoperative pneumonia or wound infection. There were also no complications during the perioperative period. One patient died 7 months after surgery.Our retrospective study demonstrates that the indicator for elective general thoracic surgery is not the CD4-positive T-lymphocyte count and that the initiation of HAART may reduce the 12-month mortality rates. In HIV-positive patients, regardless of the CD4-positive T-lymphocyte count, surgeons can operate in the same manner as they would with HIV-negative patients.

A 12-pulse phase-controlled rectifier has been used for high power applications. It consists of two sets of 6-pulse rectifiers. Basically they operate in parallel, but they operate alternately if load is light. The commutation of the DC current between the two rectifiers is examined and it is found that harmonic distortion of the input current is automatically minimized if they operate in the boundary between continuous and discontinuous conduction modes. An auxiliary voltage supply (AVS) is applied to forces the rectifiers to operate in the boundary conduction mode at any load conditions. It is found that AVS is required a bi-directional power flow. A simple AVS arrangement using a diode rectifier and a PWM inverter is proposed. Application of AVS to a conventional 12-pulse rectifier installing an interphase reactor is discussed. It is concluded that an interphase reactor is unnecessary if AVS is applied to reduce the input current harmonics.

Diode rectifiers have been widely used for an ac-to-dc converter. A big problem is that they include large harmonic components in the input currents. A 12-pulse configuration is useful for reducing them, but it still includes the (12 mplusmnl)th (m: integer) harmonics in the input currents. In order to further reduce the input current harmonics a single-phase square wave auxiliary voltage supply is inserted in the middle dc bus. It reduces harmonics especially the 11th and 13th and the harmonic characteristic becomes almost equivalent to a 24-pulse rectifier. Theoretical analysis of the combined 12-pulse diode rectifier with the auxiliary supply is presented, and a control method of the auxiliary supply is proposed. The reduction in the input current harmonics is verified by simulation and experimental results. The auxiliary supply is also applied to a 12-pulse thyristor rectifier.

Three-phase thyristor rectifiers have been used in industries for obtaining a variable dc voltage, but they have a problem of including large lower-order harmonics in the input currents. For high-power applications, a 12-pulse configuration is useful for reducing the harmonics, but it still includes the (12 m plusmn1)th (m: integer) harmonics. In order to further reduce the harmonics, this paper proposes to insert an auxiliary supply producing a square wave voltage to the dc bus of a 12-pulse phase-controlled rectifier. Theoretical investigation to reduce harmonics is presented, and a strategy to control the auxiliary supply voltage based on pulse-width-modulation is proposed. Reduction in the current harmonics is verified by simulation and experimental results. The volt-ampere (VA) rating of the auxiliary supply is about 5% of the rectifier output.

El arco aortico cervical (AAC) es una malformacion vascular poco frecuente que en ocasiones se acompana de otras malformaciones cardiovasculares. En funcion de la localizacion y del tipo de aneurisma y de otras malformaciones asociadas se seleccionan las vias de abordaje quirurgico como una toracotomia lateral y una esternotomia media. Describimos el caso de una paciente de 38 anos de edad con AAC y un aneurisma localizado entre la arteria carotida comun izquierda y la arteria subclavia izquierda, ademas de la persistencia de la vena cava superior izquierda (PCVSI). Durante la intervencion quirurgica, se reemplazo el arco aortico desde la zona distal del origen del tronco braquiocefalico derecho hasta el origen de la arteria subclavia izquierda con un injerto protesico para reconstruir la arteria carotida comun izquierda. El abordaje utilizado fue una esternotomia media. Se uso bypass cardiopulmonar (BCP) y parada cardiocirculatoria hipotermica, manteniendo una perfusion cerebral anterograda desde el tronco braquio-cefalico. La paciente fue dada de alta del hospital sin complicaciones a los 16 dias de la intervencion. Para el diagnostico de la posicion exacta del aneurisma fue util la angiografia por resonancia magnetica. La esternotomia media es la via de abordaje de eleccion en casos de aneurismas asociados a AAC o PVCSI.

La crosse aortique cervicale (CAC) est une malformation vasculaire rare qui accompagne parfois d'autres malformations cardiovasculaires. Des voies d'abord chirurgicales telles que la thoracotomie laterale et la sternotomie mediane sont choisies en fonction de la position et du type d'anevrysme et d'autres malformations associees. Nous rapportons le cas d'une malade de 38 ans ayant une CAC et un anevrysme situe entre l'artere carotide commune gauche et l'artere sous-claviere gauche en plus d'une persistance de la veine cave superieure (VCS) gauche. Au cours de l'intervention, la crosse aortique entre le tronc arteriel brachio-cephalique et l'artere sous-claviere gauche fut remplacee par une prothese avec reconstruction de l'artere carotide primitive gauche. Une sternotomie mediane fut utilisee. Un arret circulatoire hypothermique fut realise grâce a une circulation extra-corporelle (CEC) et une perfusion cerebrale anterograde fut realisee a partir du tronc brachio-cephalique. La malade sortit de l'hopital sans complication 16 jours apres l'intervention. Une arteriographie par resonance magnetique fut utile pour diagnostiquer la position exacte de l'anevrysme. En presence d'un anevrysme associe a une CAC au niveau de la crosse aortique ou a une VCS gauche, la sternotomie mediane est consideree comme la voie d'abord de choix.

Aortic surgery for progressive aortic valve disease or aortic aneurysm after previous coronary artery bypass grafting (CABG) is a challenging procedure. We report the outcome of aortic reoperation after previous CABG and evaluate our management of patent grafts and our methods for obtaining myocardial protection.Methods: From February 2001 to July 2003, 6 patients with progressive aortic valve disease and aneurysm of the thoracic aorta were operated on. The group comprised 3 men and 3 women with a mean age of 67.6 years. There were 4 patients with an aneurysm of the aortic arch, 1 with chronic ascending aortic dissection, and 1 with progressive aortic valve stenosis. The interval between previous CABG and aortic surgery was 74.0±44.2 months. All reoperations were performed via median resternotomy. Myocardial protection was obtained by hypothermic perfusion of patentin-situ arterial grafts following cold-blood cardioplegia administration via the aortic root under aortic cross clamping.Results: The operative procedure was aortic arch replacement in 4 patients, ascending aortic replacement with double CABG in 1, and aortic valve replacement in 1. All patients survived the reoperation. Postoperative maximum creatine kinase-MB was 49.2±29.8 and no new Q-waves occurred in the electrocardiogram nor were any new wall motion abnormalities recognized on echocardiography. There were no late deaths during a follow-up of 30.7 months.Conclusion: Reoperative aortic procedures after CABG can be performed safely with myocardial protection via hypothermie perfusion of a patentin-situ arterial graft. (Jpn J Thorac Cardiovasc Surg 2006; 54:155-159)

Diode rectifiers have been widely used for an ac-to-dc converter. One of their problems is that they include large lower-order harmonics in the input current. A 12-pulse diode rectifier is useful for reducing them but it still includes the (12m ± 1)th (m: integer) harmonics. In order to further reduce the input current harmonics a single-phase square wave auxiliary voltage supply is inserted in the middle dc bus of a 12-pulse diode rectifier. The purpose is to obtain a 12-pulse diode rectifier whose harmonic contents are equivalent to those of a 24-pulse diode rectifier. Theoretical analysis of the auxiliary supply assisted 12-pulse diode rectifier is presented and a control method of the auxiliary supply in relation to the dc load current is proposed. Effectiveness of an auxiliary supply is verified by simulation and experimental results.

The injection of endothelial progenitor cells and mononuclear cells derived from bone marrow at the ischemic region of peripheral artery disease patients is reported to be effective for therapeutic angiogenesis; however, these cell therapies require large amounts of bone marrow to obtain sufficient numbers of cells. To solve this problem, we attempted to culture bone-marrow-derived mesenchymal stem cells (BM-MSC), which are supposed to secrete several cytokines that promote angiogenesis. We also focused on using platelet-rich plasma (PRP) as a supplement for cell culture instead of fetal bovine serum. Human BM-MSC obtained from healthy volunteers expanded rapidly when cultured with 10% PRP prepared from their own blood. FACS analysis revealed that these cultured human MSC were homogeneous populations, and chromosomal analysis showed a normal karyotype. Moreover, the angiogenetic effect was apparent two weeks after human BM-MSC were injected into the ischemic muscle in SCID mice. Tumor formation was not detected three months after injection into SCID mice either subcutaneously or intramuscularly. To simulate clinical settings, canine BM-MSC were grown with canine PRP and injected into their ischemic muscles. We confirmed that donor cells existed in situ two and six weeks after operation without any side effects. These results suggest that cultured human BM-MSC can be a promising cell source for therapeutic angiogenesis., Highlights • Human bone marrow-derived mesenchymal stem cells cultured with own platelet rich plasma. • The angiogenetic effect of cultured human BM-MSC. • Safety evaluation of cultured human BM-MSC.

This paper gives an analysis and design of a static synchronous compensator (STATCOM) using a series-connected hybrid multi-converter system. The hybrid multi-converter system consists of two GTO converters and an IGBT converter connected in series by transformers. The proposed STATCOM has advantages that the harmonic components of the output voltage/current would be less than a conventional configuration STATCOM composed of a 12-, 24-, or 48-pulse converter; the total switching losses would be less than a PWM STATCOM; and the response would be as rapid as a PWM STATCOM. One problem of the hybrid configuration STATCOM is that it tends to operate in an over-modulation range if a considerable compensating reference change occurs. To solve this problem, this paper also proposes a variable DC voltage control strategy, where the DC voltage is adaptively adjusted in accordance with the required reactive power. The validity of the proposed configuration STATCOM and control strategies are verified by simulation and experimental results.

In the Western World ischemic coronary disease is the leading cause of morbidity and mortality. Therapeutic approaches mostly aim to restore flow to a localized segment by angioplasty or bypass surgery. Therapeutic angiogenesis and or arteriogenesis describes a strategy where blood vessel formation is induced for the purposes of treating and/or preventing ischemic disease. At present, at least 17 clinical trials of myocardial angiogenesis have been presented involving over 900 patients. Therapeutic angiogenesis makes use of the administration of angiogenic growth factor protein or gene to promote the development of endogenous collateral vessels in ischemic myocardium. Most recently, interest has grown in the potential angiogenesis effects of cell therapy--such as autologous bone marrow cells or cultured stem cells--and there are now several groups initiating phase I/II trials in this area.

In the present study, we examined a novel method of stimulating myocardial angiogenesis through ischemic preconditioning (IP) in the form of in vivo four repetitive cycles of coronary artery occlusion each followed by reperfusion. Rats divided into 4 groups: Control+Sham surgery (CS), Control+ Left anterior descending coronary artery (LAD) occlusion (CMI), IP+ Sham surgery (IPS) and IP+LAD occlusion (IPMI). For cardiac function, rats were subjected to stress testing with dobutamine after 2, 4, 7, 14 and 21 operative days. Capillary density (CD) and arteriolar density (AD) were evaluated by immunohistochemistry. Western blot was performed to examine the expression pattern for VEGF and anti-death candidates, Bcl-2 and survivin. Blood flow and the extent of endothelial and cardiomyocyte cell death were examined. The protein/DNA array was performed to determine the status of various transcription factor related to stress signal. Left ventricular functional reserve was better preserved in IPMI compared to the CMI group. The infarct size and apoptotic cell death were reduced in IPMI group significantly. Left ventricular regional blood flow, perfused capillary density and AD increased significantly in the IPMI group. VEGF, Bcl-2 and survivin expression were increased in IPMI compared to CMI. VEGF mediated vascular permeability was controlled in the IPMI due to suppression of c-Src in the infarcted myocardium. Our study documented first time the ability of IP to induce angiogenesis in the infarcted myocardium along with the activation of several transcription factors such as Stat3, Pax-5, NF kappa B, TFIID, SP1 and reduction of VEGF mediated vascular permeability by inhibition of c-Src in IPMI group thereby reducing ischemic injury in rat MI model.

An active filter (AF) is required to have a high control capability for tracking a time-varying current reference. However, a steady-state current error always exists if a conventional proportional and integral (PI) regulator is used because the current reference varies in time. This paper proposes the application of adaptive digital signal processing (ADSP) to the current control of voltage source PWM inverters. ADSP does not require any additional hardware. It can automatically minimize the mean-square error. Since the available computer processing time is limited, ADSP cannot eliminate higher-order harmonics but can eliminate lower-order harmonics such as 5th to 17th. Experimental results demonstrate that ADSP is useful for improving the reference tracking performance of voltage source inverters. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 146(4): 76–83, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10266

In this paper, a 3-phase series-connected hybrid converter system is introduced. The converter system is constructed by a GTO converter and an IGBT converter connected in series by two output transformers aiming at a high voltage high efficiency converter. The GTO converter operates in a square-wave switching mode at the same switching rate as a reference output voltage in order to minimize the device switching losses. The IGBT converter is built in an NPC (neutral-point-clamped) arrangement and operates in a PWM switching mode at a high switching rate. The former produces a base part of the total output voltage. The latter not only produces an additional part of the total output, but also offsets the harmonic components generated by the GTO converter. The control strategy for the system is proposed, and the experiment on an inverter, rectifier and STATCOM operation is demonstrated using the proposed hybrid converter. The experimental results verified the validity of the proposed hybrid configuration and its control strategy.

A hybrid converter system aims at a large capacity high voltage high efficiency converter system with being free from harmonics in the output. The system can consist of n GTO converters and a single NPC IGBT converter connected series by n+1 output transformers. It is proved that a triple converter system consists of two GTO converters and one IGBT converter is most feasible based on the performance evaluation. Thus, this paper treats a triple converter system in detail. The GTO converters operate in a square-wave switching mode, while the IGBT converter operates in a PWM switching mode. The former produces a base part of the total output voltage. The latter not only produces an additional part of the total output, but offsets the harmonic components generated by the GTO converters. The control strategy for the system is proposed, and the experiments on inverter, rectifier and STATCOM operation are demonstrated. The experimental results verified the validity of the proposed hybrid triple converter configuration and its control strategy.

To guide reconstruction of scaphoid non-union, we attempted to create full-scale models of the scaphoid by three-dimensional computed tomography (3D CT) of the healthy side. In this study, we obtained 3D scans of 51 cadaveric hands and studied the difference in morphology between genders and between the left and right sides. The major axis length on a fixed plane and Fourier transformation curve were examined. Ten scaphoid images were also obtained with 3D CT before and after removal from the cadaveric hands. Our findings suggest good correlation between models produced using 3D CT images of the scaphoid alone, and this could serve as an accurate model if the magnification is corrected using the regression line. However, the model using 3D CT images of the intact wrist joint has a large margin of error and its use will not be practical.

A new current control method based on the internal model principle in control theory is proposed. It introduces a sinusoidal internal model into the control system. It does not use any coordinate transformations. The method can be used for tracking an arbitrary number of harmonics: a DC component or fundamental frequency component signal. It is applied to a single-phase pulsewidth modulation inverter and active filter. The validity is confirmed by simulation and experimental results.

A new current control method based on the internal model principle in control theory is proposed. It uses a sinusoidal internal model, but it does not use any coordinate transformations. The method can be used for tracking an arbitrary number of harmonics, a DC component or a fundamental frequency component signal. It is applied to a single-phase PWM inverter and an active filter. Simulation and experimental results confirm the validity of the proposed method.

Background . Extensive aortic replacement in acute dissection is currently not a widely accepted method of treatment. Methods . We developed a safe method for extended aortic repair including the aortic arch in type A acute dissection, and describe here its application in 5 cases. This method was based on a modification of the elephant trunk method and several other strategies. Most of the procedures were carried out under simple hypothermic circulatory arrest. Results . All patients recovered within 2 days without recurrent nerve injury. One patient suffered from unilateral upper arm palsy due to severe innominate dissection. Patients were all discharged and early postoperative computed tomography (CT) showed thrombotic obliteration around the elephant trunk. Follow-up CT after 4 to 18 months confirmed that thromboexclusion proceeded down to the distal end of the elephant graft in 1 patient and to the diaphragmatic level in 3 patients. Total obliteration was observed in the remaining 1 patient. Conclusions . This technique enables extended aortic repair in acute dissection with no increase in morbidity, and effectively promotes thromboexclusion of the dissected lumen to a wider extent than conventional methods.

This paper describes how current harmonics or torque ripples in AC drives vary when different PWM methods or a number of output voltage levels are employed. The harmonic distortion determining factor (HDDF), which represents the intrinsic spectral property of individual PWM methods, is calculated for each of the multilevel PWM methods, and is used as a common quality index. Almost all the carrier-based PWM schemes that have been proposed so far are considered. HDDF values are, for example, helpful for designing AC drive systems because they can be used for predicting the current harmonics or torque ripples.

A new design method based on the linear-quadratic control theory is developed for the control of PWM rectifiers with sinusoidal input current. The PWM rectifiers are promising because they can supply DC power while keeping a sinusoidal AC current with unity in the fundamental power factor. There are two types, a voltage-source rectifier and a current-source rectifier. The former is required to simultaneously control both the fundamental power factor and DC voltage, while the latter does so for both the fundamental power factor and DC current. State feedback control is essentially suited for multi-input and multi-output systems such as those. Here a discrete-time optimal regulator is applied to their control because it provides a microprocessor-based robust feedback system without steady-state errors in response to step reference and/or disturbance change. The regulator is implemented using a digital-signal-processor. Experimental results demonstrate the validity.

Right aortic arch with Kommerell’s diverticulum is a very rare situation. Surgical treatment is recommended for symptomatic patients or asymptomatic patients with a large diverticulum. However planning the strategy of operation is difficult without a 3D imaging. We report a case of a 57-year-old man with right aortic arch, Kommerell’s diverticulum, and aberrant left subclavian artery. After a 3D-CT imaging, the patient underwent descending aortic replacement without reconstruction of aberrant left subclavian artery. After operation, there was no signs or symptoms of ischemia of the left arm. If the reconstruction of the aberrant subclavian artery was too difficult, closing its orifice is an acceptable decision. It has been found advantageous because of a decrease blood loss and a shorter cardiopulmonary bypass duration. If an ischemia of the arm is noticed, additional reconstruction will have to be considered. 3D-CT imaging was very useful to have a proper orientation and plan for the operative strategy.

This paper proposes a simple and practical method for improving performance of DSP-controlled current source active power filters (AF). The transfer function of a DSP-controlled AF has a phase-lag nature because there is a time lag in the control output due to the computation time required by DSP, and the converter used for AF has first order lag characteristic. As AF has to generate high frequency compensation currents, the phase-lag characteristic causes a serious deterioration in the filter performance. In the proposed system, an adaptive digital filter (ADF) is used as a series compensator of AF and it compensates for the phase-lag characteristic of AF. It was confirmed by experimental results that a simple two-tap ADF is very effective to improve AF compensation performance.

Frequency spectra of inverter output currents are one of the important factors to evaluate PWM methods. These spectra are, however, influenced not only by the PWM method itself but by the operating conditions of the inverter such as the switching frequency or load parameters. The harmonic distortion determining factor (HDDF) is considered to be a common quality index that represents the intrinsic spectral property of individual PWM methods. As it has a close relation to RMS values of the harmonic current or torque ripples of driven motors and, further, it is almost independent of the operating conditions, HDDF is quite useful for evaluating PWM methods. In this paper four typical carrier based PWM methods and two space vector based PWM methods are compared and evaluated based on the HDDF values.

The harmonic distortion determining factor (HDDF), which represents the intrinsic spectral properties of pulse-width modulation (PWM) methods, is introduced. The HDDF is almost independent of the inverter operating conditions such as the switching frequencies or load parameters if the switching frequency is 40 times greater than the output frequency. Furthermore, it is closely related to the root mean square (RMS) values of the harmonic current and motor torque ripples for induction motor drives, or the RMS values of the harmonic current and DC voltage ripples for rectifier operation. Therefore, it is useful as a common quality index for the evaluation of PWM methods. Four typical analog PWM methods and four digital PWM methods are compared and evaluated based on HDDF values. It is shown that the harmonic injected PWM for analog PWM, or the digital PWM of type C has the best characteristics. >

Low-dose aspirin (325 mg/day), administered to those with several conditions involving ischemic disorders, can cause upper gastrointestinal (GI) complications. In this prospective study, we aimed to clarify the incidence of aspirin-induced gastric ulcers in consecutive Japanese patients and identify suitable preventive measures.We recruited 125 consecutive adult outpatients who received low-dose aspirin (enteric-coated tablets 100 mg) for8 weeks. Endoscopy and blood tests were used to evaluate their gastric injury (which was scored using a modified Lanza scale) and anti-Helicobacter pylori antibody titer, respectively.We found that 39.8% of patients received either no upper GI drug or only mucoprotective drugs, 39.8% received medium-dose histamine H2 blockers, and 20.4% received proton-pump inhibitors (PPIs). Anti-H. pylori antibody titers were positive in 43.7% of patients. The incidence of definitive gastric ulcers in this population was 0.97%. Ordered logistic regression analysis revealed that the odds ratio for the increase in the modified Lanza score was 0.20 for medium-dose histamine H2 blockers and 0.09 for PPIs.The incidence of postoperative definitive gastric ulcers in Japanese patients receiving ≤100 mg enteric-coated aspirin was 0.97%. The use of PPIs and histamine H(2) blockers may prevent aspirin-induced gastric injury in such patients.

Nonlinear loads using power semiconductor devices produce harmonic currents and reactive power in AC power lines. As they are popular in many fields, the elimination of harmonic currents and reactive power is one of the important research projects.This paper describes a control method and compensation characteristics of the combined filter system of a current source active filter and a high-pass-filter. The system senses three signals, load currents, source currents and line voltages, to create the reference signals of the active filter. The goal of this paper is to solve the problems:(1) A harmonic-enlarging effect due to the parallel resonance, (2) Filtering of the harmonic currents produced by source-side harmonic voltages, and(3) Drawbacks of analog control such as being sensitive to noises, etc.The transfer function of the current source converter is identified, and is used for designing the control system of the active filter. Digital control based on a DSP is adopted to remove the drawbacks stemming from analog counterpart, but it is found that it introduces a new problem, a computational delay in the output, that results in serious deterioration of the fiter performance. It is shown that the addition of the source current feedback can solve not only the delay problem but ones due to the parallel resonance and source-side harmonic voltages.Finally a small setup controlled by a DSP was built, and the validity of the proposed method was demonstrated by experimental results.

This paper describes a method of determining parameters of PWM rectifiers based on the degrees of total harmonic distortion (THD). The inductance value of ac reactors and the capacitance value of the dc capacitor have a great influence on the amplitude of the harmonics in the ac input currents and dc output voltage, respectively. So far, simulation-based harmonic analysis is dominant. Here, the harmonic distortion determining factor is proposed that provides a simpler and broader manner of obtaining THD values, that is, it enables approximate THD values to be calculated without conducting any simulations or experiments. Finally, an experiment using a DSP is carried out to confirm the usefulness. An optimal regulator theory is applied to the controller design.

This paper describes a method of determining parameters of PWM rectifiers based on the degrees of total harmonic distortion (THD). The inductance value of AC reactors and capacitance value of DC capacitor give a great influence on the amplitude of the harmonics in the AC input currents and DC output voltage, respectively. So far simulation-based harmonic analysis is dominant. In this paper we propose the harmonic distortion determining factor that provides a simpler and broader manner of obtaining THD values, that is, it enables us to calculate approximate THD values without conducting any simulations or experiments. Finally experiment using a DSP is carried out to confirm the usefulness. An optimal regulator theory is applied to the controller design.

This paper describes a PWM pulse pattern optimization method using the carrier frequency modulation (CFM) technique. This new technique is aiming at not only reducing the magnetic acoustic noises of the driven motors but also improving the performance of sinusoidal inverters.The PWM pulse patterns are basically controlled so that the time-integral function of voltage vectors in the space vector notation may draw a circular locus. In addition to this, the carrier frequency, practically the sampling frequency for inverter control, of PWM is also regulated so that a performance index (PI), which represents the degrees of achieving objectives, may be minimized. Here two PIs, one is for minimizing the distortion of output currents and the other is for minimizing the torque ripples of driven motors, are discussed respecively.Finally, CFM is implemented using a single-chip microprocessor, and the experimental results demonstrate the validity of the proposed mehtod.

A new variable speed control method for the Commutatorless Motor is proposed on the basis of Modern Control Theory, to provide not only a quick response for speed reference but a high efficiency operation. The summarized contents of the proposed method are the following.(1) The optimum ratio of armature current to field current making the efficiency maximum is derived.(2) Ordinarily, as a commutatorles motor has an unstable tendency when it is driven in the manner of a constant commutation margin angle, the air gap flux is necessary to keep constant by sensing the air gap flux. However, the proposed method does not need the flux sensing because of estimating all the state variables with accessible state variables.(3) For reducing the production cost, the technique that constructs the feedback control system using the accessible state variables is employed.(4) As a result from considering thyristor commutating mechanism, a new current controller which protects the motor system from the commutation failure is introduced.Finally, the proposed control method is applied for the numerical commutatorless motor model, and its usefulness is confirmed through the simulation.

This paper proposes a new arrangement and new control strategy for a hybrid multi-converter system. It consists of two GTO converters and a neutral-point-clamped IGBT converter connected in series. A bulky and expensive transformer with phase-shifted secondary windings, which the original arrangement required, is not necessary. Phase-difference control between the two GTO converters is proposed and it expands the adjustable output voltage range up to 100%. Phase-difference control however increases harmonic distortion of the output voltage. Third-harmonic injection to a sinusoidal reference is also proposed to reduce the harmonic distortion. Finally, the effectiveness is verified by simulation and experimental results.

In recent years cases of delayed myelopathy following spinal compression fracture in elderly cases with osteoporosis have posed a therapeutic problem. During the past three years we have experienced 5 such cases who underwent surgical treatment in our department. All subjects were females with severe osteoporosis and a BMD of 0.395-0.527g/cm2. Their ages ranged from 62 to 88 years with 2 cases developing after trauma and 3 cases developing without remarkable trauma. Posterior vertebral body collapsed into the vertebral canal due to increased kyphosis and intervertebral necrosis leading to spinal cord compression. The mean preoperative angle of kyphosis was 29.2°, and this improved postoperatively to a mean of 12.8°. Excluding one case, improvement in both Frankel's classification and JOA score was observed within a short period after surgery to permit gait with the assistance of a cane. Since a number of points need to be clarified with regard to the type of compression fracture which leads to delayed vertebral collapse and to development of neurological symptoms, it is considered advisable to prevent delayed vertebral collapse as much as possible.

We present the case of a 53-year-old man with renal and bilateral limb ischemia due to Stanford B aortic dissection. The thrombosis of the false lumen had progressed and compressed the true lumen, developing renal and leg ischemia. Urgent graft replacement of the infrarenal abdominal aorta with proximal fenestration was successfully performed and the patient was discharged without complications.

In our study, resveratrol (polyphenol) has been identified as a very important stimulus/agent for the induction of new vessel growth. Occlusion of a main coronary depletes the blood supply to the myocardium and subsequently reduces cardiac function, which ultimately leads to heart failure. Progressive, chronic coronary artery occlusion has been shown to induce development of collateral arteries to re-establish and maintain blood flow to the myocardium at risk via the growth of new capillary vessels or angiogenesis. Studies from our laboratory, as well as from others, have already confirmed the protective role of collaterals against myocardial ischemia and cell death. We have successfully demonstrated in rat myocardial infarction (MI) model an effect of resveratrol on significant upregulation of the protein expression profiles of vascular endothelial growth factor (VEGF) and its tyrosine kinase receptor Flk-1, 3 wk after MI. Pretreatment with resveratrol also increased nitric-oxide synthase (inducible NOS and endothelial NOS) along with increased antiapoptotic and proangiogenic factors nuclear factor (NF)-kappaB and specificity protein (SP)-1. We also were able to demonstrate increased capillary density as well as improved left ventricular function by pharmacological preconditioning with resveratrol 3 wk after MI.

Three-phase thyristor converters have been used in industries for obtaining a variable DC voltage, but they have a problem that they include large lower-order harmonics in the input currents. For high power applications a 12-pulse configuration is useful for reducing them, but it still includes the (12m/spl plusmn/1)/sup th/ (m: integer) harmonics. In order to further reduce the harmonics, this paper proposes to insert an auxiliary voltage supply (AVS) to the DC bus of a 12-pulse phase-controlled rectifier. Theoretical analysis is presented, and a strategy to control AVS voltage is proposed. Reduction in the current harmonics is verified by simulation and experimental results. The VA rating of AVS is about 5% of the rectifier output.