We have carried out ultrafast pump−probe measurement of four TPM dyes, malachite green (MG), brilliant green (BG), crystal violet (CV), and ethyl violet (EV), with a time resolution of 30 fs. The pump−probe signal showed that solvent dependence arose first in the femtosecond time regime, e.g., the decay of n-butanol solution was clearly slower than the methanol solution just 50 fs after the initial photoexcitation. The signal decays in a multiexponential manner and the slower components showed stronger linear dependence on the solvent viscosity than did the faster components. We have also carried out temperature-dependent measurement of ethanol solution and calculated the activation energies from the Arrhenius plots of each components. The activation energies and effective volumes were larger for slower decays. The activation energy of the viscosity of ethanol was larger than that of the decay components of TPM dyes. These observations are explained with a combined effect of microviscosity and intramolecular relaxation. The lifetime of the transient absorption appearing at the red edge of the ground state absorption was longer than any of the reported lifetimes of the excited state absorption around 400 nm. Therefore, the red-edge absorption is assigned to the unrelaxed ground state molecule with the twisted phenyl group.

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One-color control of colorization/decolorization reactions of diarylethene molecules was attained by using nonresonant high-order multiphoton absorption processes with a near-infrared (NIR) femtosecond laser pulse at 1.28 μm with 35 fs full width at half-maximum (fwhm). The intensity of a rather weak laser pulse (<1 nJ/pulse) can induce the simultaneous three-photon absorption leading to the colorization, while much weaker intensity induces two-photon absorption resulting in the decolorization. The spatial patterning concomitant with higher-order multiphoton absorption processes was also demonstrated.

Aim: A direct oral anti-coagulant, FXa inhibitor, has been applied to the clinical treatment of myocardial infarction (MI). Experimental studies in mice indicated that FXa inhibitors reduced atherosclerosis and prevented cardiac dysfunction after coronary ligation. These studies suggested that protease-activated receptor (PAR) 2, a major receptor of activated FX, may play an important role in atherosclerosis and cardiac remodeling.Methods: The effects of a FXa inhibitor, rivaroxaban, were investigated in a new murine model of ischemic cardiomyopathy (ICM) using SR-BI KO/ApoeR61h/h mice (Hypo E mice) that developed MI by high-fat diet loading.Results: Hypo E mice were fed rivaroxaban-containing (n = 49) or control chow diets (n = 126) after the induction of MI. The survival curve of the rivaroxaban-treated group 2 weeks after the induction of MI was improved significantly as compared with the non-treatment group (survival rate: 75.5% vs. 47.4%, respectively, p = 0.0012). Echocardiography and the expression of BNP showed that rivaroxaban attenuated heart failure. Histological analyses revealed that rivaroxaban reduced aortic atherosclerosis and coronary occlusion, and markedly attenuated cardiac fibrosis. Rivaroxaban treatment decreased cardiac PAR2 levels and pro-inflammatory genes.In vitro, rivaroxaban application demonstrated the increase of cell viability against hypoxia in cardiac myocytes and the reduction of hypoxia-induced inflammation and fibrosis-related molecules in cardiac fibroblasts. The effects of the PAR2 antagonist against hypoxia-induced inflammation were comparable to rivaroxaban in cardiac fibroblasts.Conclusions: Rivaroxaban treatment just after MI in Hypo E mice prevented the progression of ICM by attenuating cardiac remodeling, partially through the suppression of the PAR2-mediated inflammatory pathway.

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