Magnetic and magnetocaloric properties of La0.55Bi0.05Sr0.4CoO3 and their implementation in critical behaviour study and spontaneous magnetization estimation

In this work, we present the results of the magnetic, critical, and magnetocaloric properties of the rhombohedral-structured La_0.55Bi_0.05Sr_0.4CoO₃ cobaltite. Based on the modified Arrott plot, Kouvel–Fisher, and critical isotherm analyses, we obtained the values of critical exponents (β, γ, and δ) as well as Curie temperature (T_C) for the investigated compound. These components were consistent with their corresponding values and they were validated by the Widom scaling law and scaling theory. The obtained critical exponents were close to the theoretical prediction of the mean-field model values, revealing the characteristic of long-range ferromagnetic interactions. The magnetic entropy, heat capacity, and local exponent n(T, μ₀H) of the La_0.55Bi_0.05Sr_0.4CoO₃ compound collapsed to a single universal curve, confirming its universal behaviour. The estimated spontaneous magnetization value extracted through the analysis of the magnetic entropy change was consistent with that deduced through the classical extrapolation of the Arrott curves. Thus, the magnetic entropy change is a valid and useful approach to estimate the spontaneous magnetization of La_0.55Bi_0.05Sr_0.4CoO₃.

In this work, we present the results of the magnetic, critical, and magnetocaloric properties of the rhombohedral-structured La_0.55Bi_0.05Sr_0.4CoO₃ cobaltite.     

Prenatal diagnois of uropathies. Ten case reports

Obstructive uropathies are a frequent cause of child renal failure. The prenatal diagnosis of such abnomalities should lead to appropriate management. OBJECTIVE: To evaluate the interest of ultrasonographic prenatal diagnosis of urinary tract malformations. PATIENTS AND METHODS: Retrospective study of 10 cases of urinary tract malformations diagnosed in utero. The mean age of the patients was 34.9 years and the mean gestational age at the prenatal diagnosis was 28.2 weeks of amenorrhea. The abnormalities diagnosed were: 2 cases of ureteropelvic junction obstruction, 3 cases of posterior urethral valves and 5 cases of mild hydronephrosis. The fetal karyotype, realised in 8 cases, was normal. In one case the urinary abnormalities was part of a multiple malformation syndrome and led to the termination of the pregnancy. 7 cases had a post-natal follow-up: 5 had a surgical management and two new borns had transient pyelectasies. The prediction of postnatal renal function is made by ultrasonographic appearance of the kidney and the amniotic fluid. Although the analysis of fetal urine for the assessment of renal function leads to conflicting results, it seems that sodium and beta-2 microglobulin urinary rates provide useful informations.     

Short coupled variant of torsade de pointes: our experience and review of the literature

We present three cases of short-coupled variant of torsade de pointes with review of the literature. These women presented with syncope or presyncope due to torsade de pointes initiated by a short-coupled premature ventricular beat and without evidence of prolonged QT. There were no electrolyte disturbances in all cases, no apparent structural heart disease in two cases and a mild interventricular septum hypertrophy in the other case. One patient took spiramycin and metronidazole and another was taking pheniramin and lincomycin without any evidence of cause to effect relationship. One patient responded to verapamil but died suddendly after 44 months of follow-up. The two others recieved implantable cardioverter-defibrillators and verapamil per os. They still alive 46 and 54 months later. Short-coupled variant of torsade de pointes have a high incidence of sudden death, so it is very important for physicians to identify and treat it promptly. Long-term verapamil treatement is effective but still insufficient and patients should be considered for implantable cardioverter-defibrillator therapy.