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Biomedical subjects

Shigeki Takahashi

Publications and source records attributed to Shigeki Takahashi.

5 recordsLinked to original sources

Simultaneous inhibition and redistribution of spontaneous light emission in photonic crystals.

Inhibiting spontaneous light emission and redistributing the energy into useful forms are desirable objectives for advances in various fields, including photonics, illuminations, displays, solar cells, and even quantum-information systems. We demonstrate both the "inhibition" and "redistribution" of spontaneous light emission by using two-dimensional (2D) photonic crystals, in which the refractive index is changed two-dimensionally. The overall spontaneous emission rate is found to be reduced by a factor of 5 as a result of the 2D photonic bandgap effect. Simultaneously, the light energy is redistributed from the 2D plane to the direction normal to the photonic crystal.

Journal Article↗

Chest wall mesenchymal hamartoma associated with a massive fetal pleural effusion: a case report.

Abstract We report on an extremely rare chest wall mesenchymal hamartoma associated with a massive fetal pleural effusion. Prenatal ultrasound examination demonstrated a heterogeneous mass in the right thorax associated with a massive pleural effusion and right lung compression at 29 weeks of gestation. The patient underwent pleuroamniotic shunting at 30 weeks and was delivered at 33 weeks by cesarean delivery secondary to fetal distress. After management of the respiratory distress and evaluation of the mass, surgery was performed at day of life 8. Histological examination confirmed the diagnosis of a chest wall mesenchymal hamartoma.

Adult↗

Modulation of masticatory muscle activity by tongue position.

The purpose of this study was to test whether the tongue position affects the electromyographic (EMG) activities of masticatory muscles. We recorded the EMG activities of the masseter and anterior temporalis muscles in 10 skeletal Class I adults. Tongue position was monitored by two pressure transducers embedded in the midpalatal region and the lingual flange of a custom-made acrylic monoblock. We instructed subjects to assume three different tongue positions: rest, superior, and anterior. Friedman's test and Sheffe's F-test were used to statistically examine differences in muscle activities induced by changes in tongue position. Significant differences were found in masseter muscle activity between the rest and anterior positions and in anterior temporalis muscle activity between the rest and both the anterior and the superior tongue positions. We concluded that masticatory muscle activity is affected by tongue position.

Adult↗

Anorectal agenesis with a rectourethral fistula diagnosed in an adult: report of a case.

We report an unusual case of anorectal agenesis with a rectourethral fistula diagnosed in a 48-year-old man. The patient presented after noticing hematuria, although he had been aware of urinary leakage from his colostomy with occasional fecal urine for about 4 years. He had had a double-barrel colostomy created soon after birth for an imperforate anus, with revision at the age of 4 years to correct a prolapse of the stoma, but his malformation had never been repaired. We performed a physical examination, which did not reveal a perineal fistula, but urethrocystography demonstrated high anorectal agenesis with a rectourethral fistula. Thus, we resected the rectourethral fistula and created an end-colostomy. The patient had an uneventful postoperative course, and was discharged in good health on postoperative day 19. To our knowledge, this is the oldest patient to be diagnosed with anorectal agenesis and undergo resection of a rectourethral fistula.

Anus, Imperforate↗