The structural, electronic, optical, thermoelectric, and magnetic properties of the Perovskite PrFeO3: DFT and Monte Carlo simulations.

CONTEXT: Nowadays, Perovskite materials with diverse compositions and structures have garnered significant attention for their potential applications across various industrial and technological fields. Here, we investigated the structural, electronic, optical, thermodynamic, thermoelectric, and magnetic properties of perovskite PrFeO3 using density functional theory and Monte Carlo simulations. The optimization results demonstrate that the ferromagnetic phase is more stable than the antiferromagnetic phase. Under the GGA + SOC + U and GGA + mBJ approaches, the electronic results of the PrFeO3 compound expose the half-metallic and magnetic behavior. It was also demonstrated that introducing dilatation strain can effectively enhance both the mechanical and thermal stability of PrFeO3. Additionally, the optical properties show that this material has potential uses for solar cells because of its capacity to absorb light in the ultraviolet (UV) spectrum. The maximum values of the Seebeck coefficient reach 90 µV/K at 1000 K, indicating the potential of PrFeO3 as an efficient thermoelectric material. The magnetic properties exhibit a first transition of spin reorientation (TSR) at 171.44 K, followed by a second-order transition at 707.15 K. This investigation provides valuable insights into the unstudied aspect of Perovskite PrFeO3. METHODS: To carry out this investigation, we employed the density functional theory (DFT) implemented in the Wien2k package. To determine the exchange-correlation potential, we utilized the GGA-PBE (Perdew, Burke, and Ernzerhof) approach. The SOC was included based on the second-variational method using scalar relativistic wavefunctions, and electron-electron Coulomb interactions for Fe and Pr are considered in the rotationally invariant way GGA + SOC + U. In this paper, the effective parameter Ueff = U - J was adopted, where U and J stand for the Coulomb and exchange parameters, respectively. Also, we opted for the modified Becke-Johnson potential (mBJ) for comparison. The thermodynamic properties are obtained using the quasi-harmonic Debye model via Gibbs2 software programs. For the calculation of thermoelectric coefficients, a combination of first-principles band structure calculations and the Boltzmann transport theory within the rigid band approximation (RBA) and the constant scattering time approximation (CSTA) was employed, utilizing the BoltzTrap code. Subsequently, we delve into the magneto-caloric and magnetic properties by employing Monte Carlo simulations.

Investigation into the physical characteristics of the compounds XBiSe2 (X = Li, Na or K).

CONTEXT: As new materials, the ternary chalcogenides have recently brought scientists' attention. These materials are a novel class of semiconducting chemical compounds. They allow the increase of the photo-conversion efficiency, the performance, and the cheap energy cost. Such materials also provide a wide range of physical and chemical applications. METHODS: The used investigation employs Density Functional Theory (DFT) implemented in the Wien2k package to systematically characterize the physical properties of ternary chalcogenide compounds XBiSe2 (X = Li, Na and K). Such method emphasizes their applicability to energy conversion technologies. Scrutinizing their electronic, optical, and thermoelectric properties elucidates the effect of alkali metal substitution on performance metrics. The results not only advance knowledge of these materials' physicochemical behaviors but also reveal their potential for tailored functionalization in next-generation energy and optoelectronic systems, marking a significant stride in material science and application-oriented research.

Germination of Astragalus hamosus L. and Coronilla scorpioides (L.) as influenced by temperature.

Seed germination of two pasture legumes was tested under dark conditions at three alternating temperatures of 5-20, 15-20, 20-35 degrees C and constant 20 degrees C. Duration of the alternating temperatures was 12 h. The seedling counts were checked every day during four weeks. Species differed significantly in germination response to temperature. A. hamosus was more sensitive to temperature than C. scorpioides. The temperature of 20-35 degrees C was more favourable for the germination of A. hamosus than constant 20 degrees C which markedly reduced its germination. The interaction between accessions and temperatures for total germination was significant in both species. In A. hamosus, almost 50% of germination was achieved by all accessions by the first week at alternating 20-35 degrees C temperature while in C. scorpioides, average total germination was significantly low (4%) even by the 28th day. A total rate of 11 and 9% of germination were recorded by two accessions from Ouesslatia (210) and Agareb (19), respectively. A considerable variation for germination was observed among accessions of both species. Temperature requirements for seed germination of the studied species suggest why they are relatively easy or difficult to establish in the field. A. hamosus, with very small seeds required relatively high alternating temperature for germination than C. scorpioides which was insensitive to temperature and has relatively bigger seeds.

[Myocardial infarction associated with stroke revealing a thrombus of the ascending aorta]. / Infarctus du myocarde associé à un accident vasculaire ischémique révélateur d'un thrombus de l'aorte thoracique ascendante.

Mobile thrombus of the ascending thoracic aorta is an uncommon source of embolism. We report the case of a 40-year-old woman, without coronary risk factors, who was admitted for an acute myocardial infarction associated with stroke. Transesophageal echocardiography showed the presence of a pedunculated highly mobile thrombus attached to the aortic wall near the right coronary ostium. With appropriate anticoagulation, the thrombus resolved after 2 weeks and no recurrence occurred over the next 18 months. Coronary angiography was normal.

Hydatid cyst of the heart located in the interventricular septum.

Cardiac hydatosis is a rare condition, and the localization of a hydatid cyst within the interventricular septum is exceptional. A 61-year-old man found to have a hydatid cyst of the interventricular septum is reported. Presenting manifestations were congestive heart failure and signs suggestive of an aortic valvulopathy. Diagnosis was made by Doppler echocardiography and confirmed by magnetic resonance imaging. The cyst was approached surgically by right ventriculotomy. Despite a technically successful intervention without rupture of the cyst or appearance of a conduction delay, the patient died on the 20th postoperative day because of acute respiratory distress syndrome complicating infectious pneumonia.