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Direct intensity modulation and wireless data transmission characteristics of terahertz-oscillating resonant tunnelling diodes (RTDs) is reported. A direct intensity modulation of the RTD oscillators was demonstrated, and the frequency response was measured. It was found that the 3 dB cutoff modulation frequency was limited by the parasitic elements of the external circuit, and increased up to 4.5 GHz by reducing such parasitic elements. Wireless data transmission by direct amplitude shift keying was demonstrated using an RTD oscillating at 542 GHz with cutoff frequency of 1.1 GHz. The BERs for bit rates of 2 and 3 Gbit/s were found to be 2 × 10 28 and 3 × 10 25 , respectively.Introduction: High-capacity short-distance wireless communication is an important application of the terahertz (THz) range [1, 2]. Thus, compact and coherent solid-state THz sources that can be modulated directly are highly desirable. A good candidate for THz sources is the resonant tunnelling diode (RTD), which can oscillate in the THz range at room temperature [3][4][5][6]. We have reported RTDs with fundamental oscillation of 1.04 THz [4] and high output power ( 400 mW) oscillation at around 550 GHz [5]. The modulation of the output of THz sources is important for communication. In this Letter, we demonstrate a direct modulation of the output power of an RTD oscillator and measure its frequency response. In addition, we also demonstrate wireless data transmission by a direct amplitude shift keying (ASK) of the RTD.

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Convulsions sometimes occur in infants and toddlers with mild gastroenteritis. We retrospectively investigated the hospital records of 106 patients admitted to our hospital who had rotavirus gastroenteritis from February 2002 to April 2008. There were 23 patients with convulsions, including 13 with benign convulsions, 9 with febrile seizures, and 1 with epilepsy. Gastroenteritis in patients with benign convulsions was mild from the viewpoint of body weights and serum creatinine concentrations on admission and the duration of admission. Serum Na(+) and Cl(-) concentrations of patients with benign convulsions were relatively lower than those without convulsions on admission (P = .006, and P = .008, respectively). Twelve of thirteen patients had no other seizures after oral administration of 5 mg/kg of carbamazepine, while 1 patient had 1 convulsion 15 minutes after the therapy. In conclusion, carbamazepine therapy was effective for benign convulsions with rotavirus gastroenteritis.

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