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Nanovehicles are a new class of molecular machines consisting of a molecular scale chassis, axles, and wheels, that can roll across solid surfaces with structurally defined directions making them of interest to synthetic chemists, surface scientists, chemical engineers, and the general car enthusiast. In this tutorial review, following a brief introduction to the development of nanomachines, our recent progress on the nanovehicle project is presented including the design, synthesis, and testing of a series of nanocars, nanotrucks, and motorized nanocars.

Age and circumstances of menopause (natural or artificial) are detailed in 104 cases of recent myocardial infarction (MI). The results of this study with statistical analysis show no correlation between the age at menopause and the age at onset of MI; so, for this study, an early menopause, cannot be considered, whatever circumstances, as a risk factor for coronary heart disease.

the causes of the necrosis. Ten cases of spontaneous regression of thymoma have been reported in the Japaneselanguage literature. In all cases, the bulk of each tumor was necrotic, with regression being thought to be related to the necrosis. Most thymomas with spontaneous regression are encapsulated, and their prognoses are good. Apparent spontaneous regression of various malignant neoplasms has been described, although as an unusual phenomenon. Most of these patients had renal cell carcinoma, malignant melanoma, or neuroblastoma. Immunologic factors have been described as playing a significant role. The spontaneous regression of thymoma has rarely been reported. We report here the case of a patient with an anterior mediastinal thymoma. The mediastinal thymoma regressed spontaneously 3 years after diagnosis without treatment. We did not obtain specimens to determine the pathologic findings after tumor regression. In this case, the spontaneous regression was seen as the complete disappearance of the tumor on radiologic imaging, with no observed intervening decrease in tumor size. This is different from previous reports. Initially, the patient did not have any symptoms or pleural effusion on follow-up chest radiography. The phenomenon of spontaneous regression may not be related to rapid enlargement and necrosis, and the actual mechanism of spontaneous regression of this thymoma is not clear. This may be clarified in a collection of similar cases. The regression of an invasive thymoma has been reported after corticosteroid therapy. Our patient did not receive any medical treatment, however, including steroids. Complete spontaneous regression of mediastinal thymomas is possible. Although the phenomenon is rare, conservative treatment may be an alternative to more aggressive therapy for patients with thymoma who are medically unfit.