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In this paper, we have investigated the influence of substitution of Nd by Sr on the structural, magnetic, and magnetocaloric properties of Nd1 − xSrxMnO3 (x = 0.3 and x = 0.4). These compounds were prepared using the solid state method. The structural, morphological, and magnetic properties of our system were characterized by XRD, MEB techniques, and a magnetometer for magnetic characterization. The Rietveld refinement has revealed the coexistence of both Pnma orthorhombic and R-3c rhombohedral phases. The magnetic data indicate that the compounds exhibit a continuous paramagnetic (PM) to ferromagnetic (FM) phase transition. In addition, the critical behavior in both compounds associated with the magnetic phase transition has been studied by the magnetization isotherms. The critical exponents are deduced using various techniques such as the modified Arrott plot, Kouvel–Fisher plot, and critical isotherm technique. Finally, the results obtained of the magnetocaloric effect are in agreement with the reported values of previous researches. These results show that our samples can be used as a magnet refrigerant at room temperature. [ABSTRACT FROM AUTHOR]

The CaSmMnO ( x=0-0.4) compounds were synthesized by a solid-solid method and characterized by XRD at room temperature. The XRD profiles were indexed with a tetragonal structure ( I/4mmm space group) for x≤0.3 and orthorhombic one ( Pnma space group) for x=0.4. The magnetic measurements were studied as a function of temperature ( T=2-300 K) and applied field ( μ H=0-10 T). When the temperature decreases, each compound has shown first a ferromagnetic-paramagnetic (FM-PM) transition and then an antiferromagnetic-ferromagnetic (AFM-FM) one. The transition temperatures are found to be Sm-doping dependent. For all compounds, a spin-glass phenomenon is evidenced by FC/ZFC magnetization curves. [ABSTRACT FROM AUTHOR]

Highlights: [•] The critical behavior is sensitive to the disorder. [•] The critical exponents not fit with any model for J4 and J5 samples. [•] The scaling plots show that the critical exponents are reliable. [•] The Griffiths phase and metamagnetic behavior lead to novel critical exponents. [ABSTRACT FROM AUTHOR]

Abstract: The effect of quenched disorder on the magnetic and transport properties of (La1−x Nd x )2/3(Ca1−y Sr y )1/3MnO3 polycrystalline samples with ( J 1(x=0,y=0); J 2(x=0.05,y=0.04); J 3 (x=0.25,y=0.20); J 4(x=0.3,y=0.24); J 5(x=0.98,y=0.8) is analyzed within the context of percolative transport and the existence of the Griffiths phase. Our results demonstrate that moderate-small chemical disorder affects the inverse dc susceptibility (T) at higher temperature revealing the presence of the Griffiths phase above the Curie temperature. We attribute the observed anomalous paramagnetic behavior to the magnetic heterogeneity caused by the segregation of short-range ferromagnetic clusters within the paramagnetic matrix. The electrical properties show the presence of a metal-insulator transition at TMI which decreases with increasing disorder σ 2. In the low-temperature ferromagnetic metallic region, the ρ data follow an empirical relation, reflecting that the conductive mechanism mainly arises from electron–electron, electron–phonon and electron–magnon scattering changed versus disorder effect. In the high-temperature paramagnetic insulating region, the ρ data for all samples follow the adiabatic small-polaron-hopping model. To understand the dependence of disorder with transport mechanism, we used the phenomenological equation for conductivity under a percolation approach, which is dependent on the phase segregation of ferromagnetic metallic clusters and paramagnetic insulating regions. Also we demonstrate that magnetoresistance (MR) increase with increasing disorder σ 2. It is very interesting to note that the MR at room temperature is enhanced, which is encouraging for potential applications. [Copyright &y& Elsevier]

Ultrasound-guided vascular access is a medical procedure that is becoming increasingly common in daily practice and is recommended to avoid iatrogenic complications. One of the procedures with a high-risk rate of complications is the vascular puncture. However, training on this technique can be challenging due to the limited availability of simulation models. We propose a simple, cost-effective, and effective ultrasound-guided vascular access simulation model that utilizes chicken breast and a urine catheter to address this need., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Authors. Published by Elsevier B.V. on behalf of African Federation for Emergency Medicine.)

Introduction: There are no clear data about the incidence and the prophylactic strategies of arterial and venous thromboembolic events (TE) in COVID-19 ambulatory patients. Thus, we conducted this study to analyze thromboembolic complications in this setting and to assess thromboprophylaxis management and outcomes in the real life., Patients and Methods: This is an observational study including Covid-19 ambulatory patients. We assessed incidence of venous and arterial TE events as well as thromboprophylaxis outcomes and hemorrhagic complications. We defined high risk thrombo-embolic factor according to the Belgian guidelines which are the only guidelines that described thromboprophylaxis in COVID-19 ambulatory patients., Results: We included 2089 patients with a mean age of 43±16 years. The incidence of 30 days venous and arterial TE complications in our cohort was 1%. Venous thromboembolic complications occurred in 0.8% and arterial thromboembolic complications occurred in 0.3%.We noted at least one high-risk TE factor in 18.5% of patients but thromboprophylaxis was prescribed in 22.5% of the cases, LMWH in 18.1%, and Rivaroxaban in 3.7%. Hemorrhagic events occurred in eight patients (0.3%): five patients showed minor hemorrhagic events and three patients showed major ones (0.14%)., Conclusions: Our study showed that the incidence of thromboembolic complications is very low in COVID-19 ambulatory patients. Paradoxically, there is an over prescription of thrombo-prophylaxis in this population., Competing Interests: The authors have declared that no competing interests exist.

This work involves the synthesis and study of physical properties of the La 0.8 Ca 0.1 Pb 0.1 Fe 0.975 Mg 0.025 O 3 compound, which has been characterized by various experimental techniques, such as X-ray diffraction, SEM and complex impedance spectroscopy. The structural study showed that the La 0.8 Ca 0.1 Pb 0.1 Fe 0.975 Mg 0.025 O 3 compound crystallized in the orthorhombic structure with the Pnma space group. The particle size and the surface morphology of this compound have been analysed using SEM. The particle size was found to be around 120 nm and we confirmed that one particle contains more than one crystallite. Importantly, the studied compound presented a giant dielectric permittivity ( ε ' of around 9 × 10 4 at high temperature and low frequencies). An equivalent electric circuit has been deduced from the Nyquist plots of the complex impedance parts ( Z '' vs. Z ') to correctly describe the electrical behavior of the La 0.8 Ca 0.1 Pb 0.1 Fe 0.975 Mg 0.025 O 3 compound. The chosen circuit consists of two cells mounted in series corresponding to the grain and grain boundary contributions. The electrode contribution has been detected from the frequency dependence of the imaginary part of modulus where the activation energy of each constitution has been calculated. The relaxation process and the electrical conductivity are attributed to the same type of charge carriers characterized by similar values of the activation energy determined from loss factor tangent (tg( δ )), the imaginary part of the permittivity and the modulus spectrum., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Introduction: Stroke is a public health problem worldwide. Community stroke knowledge is crucial to guide the prevention approach. We aimed to evaluate the level of stroke knowledge among the visitors to Emergency Centres (ECs) in the southern region of Tunisia concerning factors of risk, symptoms, and treatment of stroke., Methods: A multicenter cross-sectional survey about stroke knowledge; conducted in five ECs for 10 days. All the visitors to these ECs were invited to participate in this survey. In each center, one investigator had to conduct the questionnaire. We used the stroke knowledge test (SKT)., Results: We enrolled 839 participants aged at 44 ± 7 years and with an M/F sex-ratio at 0.9. Relatives and mass media were the most reported sources of information about stroke. In 32.3% of cases, the participants had a university schooling level. The upper quartile had an SKT score of 55% or over (n = 247; 29.4%). The SKT score was significantly higher in young, female participants, in rural centers, with a university level of schooling and with no reported chronic diseases. Receiving information about stroke through the medium of television or via relatives was an independent predictor of a high SKT score compared with other knowledge sources., Conclusion: This study emphasises the urgent need for improving the population's knowledge about stroke in Tunisia. These findings may reflect the lack of government policies for education and training on stroke. A national educating program is necessary to implement to increase stroke knowledge., Competing Interests: The authors declared no conflict of interest., (© 2018 Published by Elsevier Ltd. CC BY-NC-ND 4.0.)

Introduction: Scorpion envenomation is still a frequent occurance in tropical and subtropical regions. In Tunisia, multiple studies on scorpion envenoming have contributed to an improved understanding of cardiac dysfunction and factors predictive of poor prognosis. These previous studies have contributed to the current standardized management of envenomed patients. However, the epidemiology of scorpion envenoming in Tunisia has not been updated for more than 10 years. The aim of this study was to report an update of the epidemiological features of scorpion envenomation in the southern region of Tunisia., Methods: This is a retrospective monocentric study including all patients admitted in the emergency room for scorpion envenomation. Cases were collected from emergency medical files during a 3-year period (2013-2015). The diagnosis of scorpion envenomation was made by history of a scorpion sting. All files in which scorpion envenomation was not certain were excluded. Data are presented as mean±SD with range or percentages, as appropriate., Results: We enrolled 282 patients aged 27.4±22.8 years with a 1:1 sex ratio. During surveillance in the emergency room, 39 patients developed cardiac dysfunction. Overall, 42 patients (14.9%) were at stage 3 of severity, and 240 patients (85.1%) had moderate scorpion envenomation (stage 2). Only 1 patient died a few hours after admission. In the remaining cases, the outcome was good. Our results show the improvement in mortality rates even in severe presentations., Conclusion: This study found that the outcome of scorpion-stung patients has clearly improved. This enhancement can be explained by early medical consultation and standardized management of patients with predictive factors for cardiac dysfunction., (Copyright © 2017 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.)