New source of MeV negative ion and neutral atom beams.

The scenario of "electron-capture and -loss" was recently proposed for the formation of negative ion and neutral atom beams with MeV kinetic energies. However, it does not explain why the formation of negative ions in a liquid spray is much more efficient than with an isolated atom. The role of atomic excited states in the charge-exchange processes is considered, and it is shown that it cannot account for the observed phenomena.

Pair creation in collision of γ-ray beams produced with high-intensity lasers.

Direct production of electron-positron pairs in two-photon collisions, the Breit-Wheeler process, is one of the basic processes in the universe. However, it has never been directly observed in the laboratory because of the absence of the intense γ-ray sources. Laser-induced synchrotron sources emission may open a way to observe this process.

Antenatal small-bowel volvulus without malrotation: ultrasound demonstration and discussion of pathogenesis.

We present a case of volvulus without malrotation in a twin fetus where serial antenatal US assisted in the diagnosis and ensured prompt postnatal surgical treatment. When a fetal subumbilical intestinal mass is seen, changing its echogenicity from complex to cystic, and associated with progressive proximal small-bowel obstruction and/or bowel perforation, small-bowel volvulus should be included in the differential diagnosis.

Intraperitoneal fluid in children: normal ultrasound findings depend on which scan head you use.

Background: The detection of small quantities of unsuspected free intraperitoneal fluid (IPF) at US examination in children has increased markedly in our department since linear high-frequency probes have been used routinely for gastrointestinal examinations. Its clinical significance is unknown. OBJECTIVE.

Orthotopic liver transplants in children: change in hepatic venous Doppler wave pattern as an indicator of acute rejection.

Purpose: To determine whether a change in hepatic venous flow pattern can be seen during hepatic graft rejection and if it is reversible with treatment.

Materials And Methods: Thirty-nine children received 42 liver allografts during a 10-year span. Doppler ultrasonographic (US) recordings of hepatic venous wave patterns were reviewed.