This paper presents both experimental and modeling studies of viscoelastic properties of MR elastomers under harmonic loadings. Magnetorheological elastomer (MRE) samples were fabricated by mixing carbonyl iron power, silicone oil, and silicone rubber and cured under a magnetic field. Its steady-state and dynamic properties were measured by using a parallel-plate rheometer. Various sinusoidal loadings, with different strain amplitude and frequencies, were applied to study the stress responses. The stress-strain results demonstrated that MR elastomers behave as linear visocoelastic properties. Microstructures of MRE samples were observed with a scanning electron microscope. A four-parameter linear viscoelatic model was proposed to predict MRE performances. The four parameters under various working conditions (magnetic field, strain amplitude, and frequency) were identified with the MATLAB optimization algorithm. The comparisons between the experimental results and the model predictions demonstrate that the four-parameter viscoelastic model can predict MRE performances very well. In addition, dynamic properties of MRE performances were alternatively represented with equivalent stiffness and damping coefficients.

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The inhibitory effects of a novel, orally active matrix metalloproteinase (MMP) inhibitor, ONO-4817, on the development of uterine adenomyosis induced experimentally by pituitary grafting were examined in mice. Mice were given transplants of isologous anterior pituitary glands (PGs) into the right uterine lumen at 7 weeks of age and were fed chow containing 0.1% to 1.0% ONO-4817 from 8 to 14 weeks of age. Mice treated with 0.3% or 1.0% ONO-4817 showed a significantly lower incidence of the development of adenomyosis than vehicle-treated mice. To evaluate the inhibitory effects of ONO-4817 on the progression of the invasion of the adenomyotic tissues, mice receiving PG grafts at 7 weeks of age were treated with 1.0% ONO-4817 from 13 to 17 weeks of age. The degree of pathological progression of adenomyosis was graded from 1 to 5 in increments of 1. The degree of the progression of the lesion was less in the uteri exposed to ONO-4817 (2.71 ± 0.93) than in the uteri not exposed to the inhibitor (4.33 ± 0.75). Finally, the invasiveness of endometrial stromal cells obtained from adenomyotic uteri into Matrigel consisting mainly of type IV collagen and laminin was examined using an invasion assay. The assay showed that the treatment with ONO-4817 markedly suppressed the invasion of the stromal cells of the adenomyotic uteri into the gel. These results indicate that ONO-4817 may be an effective inhibitor of the development of adenomyosis.