Extrahepatic Portal Hypertension following Liver Transplantation: a Rare but Challenging Problem

This study reports our experience of 8 cases of extrahepatic portal hypertension after 273 orthotopic liver transplantations in 244 adult patients over a 10- year period. The main clinical feature was ascites, and the life-threatening complication was variceal bleeding. Extrahepatic portal hypertension was caused by portal vein stenosis in 6 patients, and left-sided portal hypertension in 2 patients after inadventent ligation of portal venous tributaries or portasystemic shunts. All patients with portal vein stenosis had complete relief of portal hypertension after percutaneous transhepatic venoplasty (n=4) or surgical reconstruction (n=2), after a median follow-up of 33 (range: 6–62) months. Of the 2 patients with left-sided portal hypertension, one died after splenectomy and one rebled 6 months after left colectomy. This study suggests that extrahepatic portal hypertension is a series complication after liver transplantation that could be prevented by meticulous portal anastomosis and closure of portal tributaries or portasystemic shunts to improve the portal venous flow. However, any ligation has to be performed under ultrasound guidance to avoid inadventent venous ligations

An ion ring in a linear multipole trap for optical frequency metrology

A ring crystal of ions trapped in a linear multipole trap is studied as a basis for an optical frequency standard. The equilibrium conditions and cooling possibilities are discussed through an analytical model and molecular dynamics simulations. A configuration which reduces the frequency sensitivity to the fluctuations of the number of trapped ions is proposed. The systematic shifts for the electric quadrupole transition of calcium ions are evaluated for this ring configuration. This study shows that a ring of 10 or 20 ions allows to reach a short term stability better than for a single ion without introducing limiting long term fluctuations

Terahertz frequency standard based on three-photon coherent population trapping

A scheme for a THz frequency standard based on three-photon coherent population trapping in stored ions is proposed. Assuming the propagation directions of the three lasers obey the phase matching condition, we show that stability of few 10$^{-14}$ at one second can be reached with a precision limited by power broadening to $10^{-11}$ in the less favorable case. The referenced THz signal can be propagated over long distances, the useful information being carried by the relative frequency of the three optical photons.Comment: article soumis a PRL le 21 mars 2007, accepte le 10 mai, version 2 (24/05/2007

Active optics for the interrogation of a single ion

4 pagesInternational audienceThe signal-to-noise ratio in the detection of a single ion is one of the determining factors in the speed of the detection of the ion's internal states. Its value defines the necessary interrogation time to distinguish between an ion in the "on" and an ion in the "off" state. The improvement of the detection signal by means of active optics is a new approach in single-ion experiments. They accompany further progress in the stabilization of the clock laser for the single ion interrogation

Методическая работа в дошкольной образовательной организации как условие развития профессионально-педагогической культуры педагогов

Тема работы актуальна. В ВКР представлена методическая работа с педагогами ДОУ, по формирования профессионально-педагогической культуры. Работа имеет практическую значимост