P-systems in regular semigroups

In this paper, firstly it is shown that a regular semigroup S becomes a regular *-semigroup (in the sense of [1]) if and only if S has a certain subset called a p-system. Secondly, all the normal *-bands are completely described in terms of rectangular *-bands (square bands) and transitive systems of homomorphisms of rectangular *-bands. Further, it is shown that an orthodox semigroup S becomes a regular *-semigroup if there is a p-system F of the band E_S of idempotents of S such that F∋e, E_S∋t, e≥t imply t∈F. By using this result, it is also shown that F is a p-system of a generalized inverse semigroup S if and only if F is a p-system of F_S. Dedicated to Professor L. M. Gluskin on his 60th birthday     

Pulmonary toxicity of indium arsenide and arsenic selenide following repeated intratracheal instillations to the lungs of hamsters

Chronic toxicity of indium arsenide (InAs) and arsenic selenide (As₂Se₃) was studied in male Syrian golden hamsters which received InAs or As₂Se₃ particles, each containing a total dose of 7.5 mg of arsenic, by intratracheal instillations once a week for 15 weeks. As a control, hamsters were treated with the vehicle, phosphate buffer solution. During their total lifespan, the cumulative body weight gain of the hamsters in the InAs group was suppressed significantly compared with that in the control group, but not in the As₂Se₃ group when compared with that in the control group. However, the survival rate for the InAs group was significantly higher compared with the control group, but not for the As₂Se₃ group when compared with the control group. During the animals' total lifespan, one lung adenoma was seen in the 27 hamsters in the InAs group and one lung adenoma in the 23 hamsters in the control group. No tumors of the lung were observed in the As₂Se₃ group. Malignant tumors outside the lung appeared in four hamsters in the InAs group and in two in the As₂Se₃ group. No non-lung malignant tumours were seen in the control group. Total tumor incidence rates were 25.9% (7/27) in the InAs group, 10.3% (3/29) in the As₂Se₃ group and 8.7% (2/23) in the control group. There were therefore no significant differences in tumor incidence between the InAs or the As₂Se₃ group, and the control group. Regarding histopathological findings in the lung, incidence rates of proteinosis-like lesions, pneumonia, metaplastic ossification and emphysema were seen only in the InAs group, and alveolar or bronchiolar cell hyperplasia observed in both the InAs and the As₂Se₃ groups were at significantly higher rates than those in the control group. From these results, it was concluded that InAs and As₂Se₃ particles could induce pulmonary toxicity when instilled intratracheally into hamsters. A great deal of attention should be paid to the toxicity of both InAs and As₂Se₃, even though in this study the adverse health effects of As₂Se₃ appeared to be less than those of InAs.     

Highly-regulated nanocoatings of polymer films on carbon nanofibers using ultrasonic irradiation

It was demonstrated that nanoprecise coatings of uniform and densely packed polymer layers on nanomaterials and uniform polymer coatings on individual nano-objects are formed using ultrasonic effects.     

A self-organized mesh generator using pattern formation in a reaction–diffusion system

A new type of mesh generator is developed by using a self-organized pattern in a reaction–diffusion system. The system is the Gray–Scott model, which creates a spot pattern in a specific parameter region. The spots correspond to nodes of a mesh. The mesh generator has several advantages: the algorithm is simple and processes to improve the mesh, such as smoothing, (locally) addition, and removal of nodes, are automatically performed by the system.