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We have studied a hybrid nanoelectronic system which consists of an AlGaAs/GaAs two-dimensional electron gas (2DEG) in close proximity (~70 nm) to an Al superconducting nanofilm. By tuning the current through the Al film, we can change the conductance of the 2DEG and furthermore vary the effective disorder in the Al superconducting film in a controllable way. When a high current is injected into the film, screening which couples the Al film and the 2DEG results in a collapse of anti-symmetric behavior in the current-voltage characteristics, V(I) ~ -V(-I), which holds true in a conventional superconductor. Our results may open a new avenue of experimentally realizing a superconducting diode.

Magnetotransport measurements are performed on an aluminum thin film grown on a GaAs substrate. A crossover from electron- to hole-dominant transport can be inferred from both longitudinal resistivity and Hall resistivity with increasing the perpendicular magnetic field B. Also, phenomena of localization effects can be seen at low B. By analyzing the zero-field resistivity as a function of temperature T, we show the importance of surface scattering in such a nanoscale film.

Three cases of duplications of the alimentary tract are presented. Case 1 was a 5-month-old male baby. He was admitted due to copiously painless rectal bleeding. Tc-99m pertechnetate scanning revealed unusual tubular and spherical lesions. Laparotomy findings were that a tubular ileal duplication m assured 100cm or so in length and communicated with ileal lumen by its distal orifice. Moreover, there were 2 spherical duplications like ping-pong ball in morphology located in neighboring mesentery. Case 2 was a 2-day-old male newborn. He was admitted because of persistent bilious vomiting on his second day of life. Plain film x-ray revealed dilated stomach and scanty bowel gas. Laparotomy finding was that a cystic duplication measured 1.5cm in length which located in and obstructed the lumen of proximal jejunum. Also there was a distal orifice of duplication in communication with jejunal lumen. Case 3 was a 4-year-and-4-month-old boy who admitted after intermittently non-projectile vomiting for a period of 1 1/2 year. Sonography showed a calcification lesion at right upper quadrant of abdomen. Panendoscopy saw a refraction at second part of duodenum. The findings of laparotomy were that 2 tumor masses laid upon gastrocolic ligament. One was ossified soft tissue (gastrocolic ligament) with 1.5 x 1 x 0.8cm3 in size, and the other was cystic duplication of transverse colon in contact with beneath mesocolon. All duplications of 3 cases were lined with ectopic gastric and small intestinal mucosa, and ulcerative lesion was found in case 3 only. All lesions were resected and removed with good results.