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In this study, we verify the performance of the simultaneous equations method using an experimental active noise control system. The simultaneous equations method is based on a priciple different from the filtered-x algorithm requiring a filter modeled on a secondary path from a loudspeaker to an error microphone. Instead of the filter, called the secondary path filter, this method uses an auxiliary filter identifying the overall path consisting of a primary path, a noise control filter and the secondary path. As inferred from the configuration of the overall path, the auxiliary filter can provide two independent equations when two different coefficient vectors are given to the noise control filter. The method thereby estimates the coefficient vector of the noise control filter minimizing the output of the error microphone. In this paper, we propose the application of a frequency domain adaptive algorithm to the identification of the overall path. An improvement in the noise reduction speed is thereby expected. In this paper, we also present computer simulation results demonstrating that the simultaneous equations method can automatically recover the noise reduction effect degraded by path changes, and finally, using an experimental system, we indicate that the method successfully works in practical systems.

The relationship between pneumatosis cystoides intestinalis (PCI) and occupation was studied in 66 patients reported in Japan during a 5-yr-period from 1979-1983. Information concerning their occupation was obtained from 37 (56.1%) patients; 16 patients had secondary PCI and 21 had primary PCI. No particular characteristics were noted in the occupations of secondary PCI patients. Primary PCI, occurring more frequently in females (15/21), affected predominantly the large intestine (20/21), locally involving the sigmoid colon in the majority (14) of the patients. Most patients with primary PCI (16/21) were factory workers, of whom 15 (71.4%) were engaged in degreasing of manufacturing products with trichloroethylene. The high percentage of trichloroethylene workers among the patients with primary PCI suggests that occupational exposure to this agent constitutes an etiological factor in the development of this disease.

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Alogliptin (1) benzoate is a potent, highly selective inhibitor of serine protease dipeptidyl-peptidase IV, approved by US FDA for the treatment of type 2 diabetes. Herein, we report a more cost-effective process that includes ruthenium-catalyzed asymmetric hydrogenation followed by Hofmann rearrangement of 2-((6-chloro-3-methyl-2,4-dioxo-3,4-dihydropyrimidin-1­(2H)-yl)­methyl)­benzonitrile (10) to introduce a chiral amino moiety at a late stage. Use of an inexpensive and readily available nicotinamide (6) for a chiral aminopiperidine core and iodobenzene diacetate (PIDA) under mild and specific conditions allowed us to access 1 with excellent total yield and comparable quality to that manufactured by the original process.