Improved efficiency of heat generation in nonlinear dynamics of magnetic nanoparticles.

The deterministic Landau-Lifshitz-Gilbert equation has been used to investigate the nonlinear dynamics of magnetization and the specific loss power in magnetic nanoparticles with uniaxial anisotropy driven by a rotating magnetic field. We propose a new type of applied field, which is "simultaneously rotating and alternating," i.e., the direction of the rotating external field changes periodically. We show that a more efficient heat generation by magnetic nanoparticles is possible with this new type of applied field and we suggest its possible experimental realization in cancer therapy which requires the enhancement of loss energies.

Acute pancreatitis during pregnancy: a review.

This article aims to draw together recent thinking on pregnancy and acute pancreatitis (AP), with a particular emphasis on pregnancy complications, birth outcomes and management of AP during pregnancy contingent on the etiology. AP during pregnancy is a rare but severe disease with a high maternal-fetal mortality, which has recently decreased thanks to earlier diagnosis and some maternal and neonatal intensive care improvement. AP usually occurs during the third trimester or the early postpartum period. The most common causes of AP are gallstones (65 to 100%), alcohol abuse and hypertriglyceridemia. Although the diagnostic criteria for AP are not specific for pregnant patients, Ranson and Balthazar criteria are used to evaluate the severity and treat AP during pregnancy. The fetal risks from AP during pregnancy are threatened preterm labor, prematurity and in utero fetal death. In cases of acute biliary pancreatitis during pregnancy, a consensual strategy could be adopted according to the gestational age, and taking in consideration the high risk of recurrence of AP (70%) with conservative treatment and the specific risks of each treatment. This could include: conservative treatment in first trimester and laparoscopic cholecystectomy in second trimester. During the third trimester, conservative treatment or endoscopic retrograde cholangiopancreatography with biliary endoscopic sphincterotomy, and laparoscopic cholecystectomy in early postpartum period are recommended. A multidisciplinary approach, including gastroenterologists and obstetricians, seems to be the key in making the best choice for the management of AP during pregnancy.

Magnetic particle hyperthermia: Néel relaxation in magnetic nanoparticles under circularly polarized field.

The mechanism of magnetization reversal in single-domain ferromagnetic particles is of interest in many applications, in most of which losses must be minimized. In cancer therapy by hyperthermia the opposite requirement prevails: the specific loss power should be maximized. Of the mechanisms of dissipation, here we study the effect of Néel relaxation on magnetic nanoparticles unable to move or rotate and compare the losses in linearly and circularly polarized fields. We present exact analytical solutions of the Landau-Lifshitz equation as derived from the Gilbert equation and use the calculated time-dependent magnetizations to find the energy loss per cycle. In frequencies lower than the Larmor frequency, linear polarization is found to be the better source of heat power, at high frequencies (beyond the Larmor frequency) circular polarization is preferable.

[Postpartum endocrine syndrome]. / Syndromes endocriniens du post-partum.

Postpartum endocrine syndromes occur in the year after delivery. They are due to immunologic and vascular modifications during pregnancy. The Sheehan syndrome is the first described postpartum endocrine syndrome and consists on a hypophyse necrosis in relation with a hypovolemic shock during delivery. The immunologic consequences of the pregnancy are the most frequent, sometimes discrete and transitory. The physiological evolution of the endocrine glands during pregnancy and the most frequent post-partum endocrine syndromes are discussed: postpartum lymphocytic hypophysitis, thyroiditis and Sheehan' syndrome.