Use of Microtremors for the Estimation of Ground Vibration Characteristics

Short-period micro tremor array observation is conducted at five sites in the Tokyo Metropolitan area of Japan. The Fourier spectra of horizontal and vertical components show variations in time, but their ratio is stable for different time instants. The characteristics of the amplitude ratio are similar to that of Rayleigh wave and the period correspond to the peak ratio correspond to the predominant period of the sites for shear wave propagation. A parametric study for two-layered models reveals that the peaks for Rayleigh wave and shear wave are close for the ground having large impedance ratio. The F-K spectrum analysis using vertical components obtained the phase velocity close to the dispersion curve for the Rayleigh wave

Case report: Young-onset large vessel ischemic stroke due to hyperhomocysteinemia associated with the C677T polymorphism on 5,10-methylenetetrahydrofolate reductase and multi-vitamin deficiency

Hyperhomocysteinemia is an important risk factor for cerebral infarction. Herein, we report on a 30-year-old man previously diagnosed with epilepsy who presented with right hemiplegia and total aphasia. Magnetic resonance imaging showed a fronto-temporal ischemic lesion due to occlusion of the left middle cerebral artery. Clinical testing and imaging demonstrated that he had hyperhomocysteinemia induced by multiple factors including the C677T polymorphism on 5.10-methylenetetrahydrofolate reductase (MTHFR), and multiple vitamin deficiencies. The C677T polymorphism on MTHFR is closely related to hyperhomocysteinemia and folate deficiency in epileptic patients who are taking multiple anti-convulsants. Given hyperhomocysteinemia can independently cause stroke at a young age, physicians should periodically examine plasma homocysteine and serum folic acid levels in epileptic patients who are on long-term regimens of multiple anti-epileptic drugs