Robust control with pole assignment in a specified region for systems under parameter perturbations; application to a nonlinear system

This paper deals with the problem of determination of feedback gains in order to achieve required performances under linear time invariant perturbations. Based upon the Lagrange multiplier method, the proposed method determines feedback gains that ensure both robust stability and robust performance for a linear uncertain system. It is applied to a nonlinear crane system control design. The nonlinear system is first partitioned into some uncertain linear systems. Then the proposed method is applied to each uncertain linear system. Application is easily demonstrated and, consequently, a nonlinear crane control system can be easily designed. Finally, it is shown in a numerical example that the proposed method is effective.     

Differentiation of renal cell carcinomas from angiomyolipomas by ultrasonic frequency dependent attenuation

PURPOSE: We determined the usefulness of ultrasonic frequency dependent attenuation in differentiating hyperechoic renal cell carcinoma from angiomyolipoma. MATERIALS AND METHODS: Frequency dependent attenuation values were determined in 29 renal cell carcinomas and 13 angiomyolipomas. RESULTS: Frequency dependent attenuation values were significantly lower in renal cell carcinomas than in angiomyolipomas (0.42 versus 0.76 dB./cm./MHz.). Two of the renal cell carcinomas were as hyperechoic as the angiomyolipomas but they were clearly differentiated by the low frequency dependent attenuation. Two other renal cell carcinomas exhibited high values because of the abundance of fibrous tissue. However, they were readily diagnosed by the typical low echoic B-mode images. Frequency dependent attenuation did not differ between histological types of renal cell carcinoma. One angiomyolipoma that was poor in fat and rich in muscle components had an exceptionally low frequency dependent attenuation. Therefore, frequency dependent attenuation values can be regarded as an inversion of computerized tomography numbers. CONCLUSIONS: Frequency dependent attenuation measurement is a promising diagnostic aid in differentiating hyperechoic renal cell carcinomas from angiomyolipomas.     

Two cases of cystic fibrosis in Japanese/German twins

We report a case of twins with cystic fibrosis. The twins are of mixed parentage, having a Japanese mother and a German father. One case presented with meconium ileus as a neonate. The other twin was relatively healthy until the age of 6, when she was first hospitalized with a diagnosis of pulmonary aspergillosis. They have been receiving standard therapies in the United States, including digestive enzymes, vitamins, and periodic antibiotics. At the age of 19 both patients received home intravenous antibiotic therapy, and began to use an inhaled DNase at the age of 20. When the patients were 19 they were screened for the common mutations causing cystic fibrosis, and the delta F508 CFTR mutation was identified. We analyzed their CFTR genes, as well as those of their Japanese mother and grandmother. Missense mutations at exon 7 (R347H) and exon 16 were found (D979A) in the twins and in their Japanese mother.     

Successful radiofrequency current catheter ablation of accessory atrioventricular pathway after tricuspid replacement in Ebstein's anomaly

A 15-year-old female with Ebstein's anomaly was referred to hospital for radiofrequency (RF) current catheter ablation of her refractory paroxysmal supraventricular tachycardia (PSVT) after tricuspid valve replacement. A surface ECG showed ventricular preexcitation of type B Wolff-Parkinson-White (WPW) syndrome. In a baseline electrophysiological study, two types of PSVT with left and right bundle branch block (LBBB and RBBB) configurations were induced. The LBBB type was antidromic and the RBBB type was orthodromic atrioventricular reciprocating tachycardia (AVRT) with a right posterolateral accessory pathway. RF current was successfully delivered at the posterolateral site above the prosthetic valve (V-delta interval = -30 msec). The patient has been free from arrhythmias during a follow-up period of 9 months. RF current ablation seems to be useful for AVRT patients with corrected Ebstein's anomaly.     

Battery performances and thermal stability of polyacrylonitrile nano-fiber-based nonwoven separators for Li-ion battery

The microporous polyacrylonitrile (PAN) nonwoven separators have been developed by using electrospun nano-fibers with homogeneous diameter of 380 and 250 nm. The physical, electrochemical and thermal properties of the PAN nonwovens were characterized. The PAN nonwovens possessed homogeneous pore size distribution with similar pore size to the conventional microporous membrane separator. Moreover, the PAN nonwovens showed higher porosities, lower gurley values and better wettabilities than the conventional polyolefin microporous separator. Cells with the PAN nonwovens showed better cycle lives and higher rate capabilities than that of a cell with conventional one. Any internal short circuit was not observed for the cells with the PAN nonwovens during charge–discharge test. Hot oven tests for the charged cells up to 4.2 V have revealed that the PAN nonwoven was thermally stable at 120 °C, but showed shrinkage of about 26% isotropically after the test at 150 °C for 1 h. The Celgard membrane showed uniaxial shrinkage of about 30% along the machine direction at 150 °C for 1 h.     

A convenient method to determine the Rayleigh ratio with uniform polystyrene oligomers

The Rayleigh ratio of toluene at 25°C for a wavelength of 632.8 nm was determined by static light scattering measurement of a certified polystyrene reference material PS 2400 with exactly evaluated or certified mass‐average molecular mass (M_w). At first, static light scattering measurements were carried out for PS 2400 in toluene with a literature value of the Rayleigh ratio of toluene. Then, corrections of degree of depolarization, density fluctuations, and molecular mass dependence of refractive index increment were applied to the observed M_w of PS 2400 to obtain apparent M_w. Finally, from the ratio between the apparent M_w and the certified M_w, the Rayleigh ratio of toluene was reevaluated. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99:1953–1959, 2006     

A four-input beam-forming downconverter for adaptive antennas

A four-input beam-forming downconverter for adaptive antennas is described. It consists of 2-bit variable gain amplifiers (VGAs), 5-bit local oscillator (LO) signal phase shifters using double RC-bridge circuits, and mixers. The VGAs adjust gain deviation between signal paths. A differential-signal-to-eight-phase-signal converter is employed as a part of the LO phase shifter to reduce the chip size. A maximum phase error of 4.1/spl deg/, which is less than 1/2 LSB, is achieved. This error value indicates that the required phase shifter accuracy and the necessary isolation between the VGAs has been achieved. This beam-forming IC is applicable to receivers with adaptive antennas, and is expected to help to reduce the costs of adaptive antenna systems.     

Study on pyrogen in natural and cultivated edible mushrooms

We examined endotoxin and pyrogen contents in several kinds of natural and cultivated edible mushrooms, as well as some cultivated vegetables. According to the Japanese Pharmacopoeia, 14th Ed., two types of endotoxin (gel-clot Limulus amebocyte lysate) test and the pyrogen test were performed using natural edible mushrooms collected in Aichi Prefecture and cultivated mushrooms and vegetables purchased at a market. The endotoxin contents of natural mushrooms were apparently higher than those of cultivated mushrooms or vegetables. The endotoxin contents in the cultivated mushrooms were slightly higher than those in the vegetables. Similar results were obtained in the pyrogen test.     

Radiotherapy of T1 and T2 glottic cancer: analysis of anterior commissure involvement

The principles and applications of chromatographic separation of enantiomers in pharmaceutical analysis have been reviewed. Several of recently reported enantioselective analysis of various racemic drugs using both the 'indirect' and 'direct' methods have been presented.