Discrimination of particles has been investigated by using tactile information in an artificial system. Two kinds of time-series signals, i.e. normal and tangential fluctuations, were obtained ...experimentally when two silicone-gum specimens were rubbed with sands between the surfaces of specimens, in which the sands with sizes of 20-710 I.Lm were classified into nine samples by sieves. The particle diameters of samples were found to be correlated with two quantities obtained from the time-series signals ; one was the normal elastic recovery between before and after rubbing, and the other was the weighted mean frequency of dominant elements appearing in the spectrum of tangential fluctuation. By using the relationship between the two quantities and the particle diameters, the artificial system showed an ability of discrimination comparable with human subjects. Information of the size of sands appears in three ways. In case of larger-size samples, it appears strongly in the weighted mean frequency with lower-range frequency. On the contrary, it appears strongly in the elastic recovery for middle-size samples, and in the weighted mean frequency with higher-range frequency for smaller-size samples. By considering such characteristics, an algorithm has been constructed for discriminating the all samples with a higher accuracy, which has a similarity to the functions of three kinds of tactile receptors.
Humans obtain some tactile feeling when they touch and rub objects with their fingers, which should be associated with some information about the objects. It means tactile information exists in such ...tribological actions of their fingers inevitably. In the present study, discrimination of particles has been investigated by using tactile information in an artificial system. Two kinds of time-series signals, i.e. normal and tangential fluctuations, were obtained experimentally when two silicone-gum specimens were rubbed with sands between the surfaces of specimens, in which the sands with sizes of 180-710 were classified into five samples by sieves. The particle diameters of samples were found to be correlated with two quantities obtained from the time-series signals ; one was the normal elastic recovery between before and after rubbing, and the other was the weighted mean frequency of dominant elements appearing in the spectrum of tangential fluctuation. By using the relationship between the two quantities and the particle diameters, the artificial system showed an ability of discrimination comparable with human subjects.
T(h) cells have long been divided into two subsets, T(h)1 and T(h)2; however, recently, T(h)17 and inducible regulatory T (iTreg) cells were identified as new T(h) cell subsets. Although T(h)1- and ...T(h)2-polarizing cytokines have been shown to suppress T(h)17 and iTreg development, transcriptional regulation of T(h)17 and iTreg differentiation by cytokines remains to be clarified. In this study, we found that expression of the growth factor independent 1 (Gfi1) gene, which has been implicated in T(h)2 development, was repressed in T(h)17 and iTreg cells compared with T(h)1 and T(h)2 lineages. Gfi1 expression was enhanced by the IFN-gamma/STAT1 and IL-4/STAT6 pathways, whereas it was repressed by the transforming growth factor-beta1 stimulation at the promoter level. Over-expression of Gfi1 strongly reduced IL-17A transcription in the EL4 T cell line, as well as in primary T cells. This was due to the blockade of recruitment of retinoid-related orphan receptor gammat to the IL-17A promoter. In contrast, IL-17A expression was significantly enhanced in Gfi1-deficient T cells under T(h)17-promoting differentiation conditions as compared with wild-type T cells. In contrast, the impacts of Gfi1 in iTregs were not as strong as in T(h)17 cells. Taken together, these data strongly suggest that Gfi1 is a negative regulator of T(h)17 differentiation, which represents a novel mechanism for the regulation of T(h)17 development by cytokines.
PDF
