Synthesis, characterization, and sensitivity tests of La0.8Ba0.1Bi0.1FeO3 nanoparticles towards a few parts-per-billion of acetone gas

In the present paper, the La0.8Ba0.1Bi0.1FeO3 powders were synthesized via the auto-combustion method. The optical, the positron annihilation spectroscopy and the gas sensing properties of our sample were investigated simultaneously. FTIR spectrum revealed the antisymmetric deformation vibrations of the Fe-O and Fe-O-Fe bonds inside the octahedron FeO6. The optical bandgap (Egap) of the La0.8Ba0.1Bi0.1FeO3 compound was found to be equal to 2.23 eV. We confirmed by the positron annihilation studies, the existence of open volume defects and vacancy sized defects, at the grain/interfaces between vacancy clusters and grains at the interfaces intersection (triple-lines). Notably, the La0.8Ba0.1Bi0.1FeO3 perovskite exhibits an excellent response toward acetone gas, with ultra-fast response and recovery times to some parts-per-billion (ppb) of this tested gas.

Sediment recontamination potential and biological impacts of hydrophobic organics from stormwater in a mixed-use watershed

This study focused on understanding the influence of stormwater on sediment recontamination and biota bioaccumulation. Stormwater and sediment sampling was conducted at Paleta Creek San Diego, CA, a mixed-use urban watershed. Stormwater samples were size fractioned into clay, silt, sand, and filtered fractions to better understand the association of PAHs and PCBs with different particle sizes. Settling traps were deployed during storm seasons to capture solid particles deposited by stormwater. Bioaccumulation studies of the receiving water sediments were conducted on bent-nosed clams (Macoma nasuta) both in-situ and ex-situ. The results indicated that the majority of PAHs and PCBs were discharged during the early stages of the storm and were primarily associated with coarser particles (>20 μm). Sediment near the discharge exhibited higher levels of contaminants, consistent with the findings from the settling traps and stormwater discharges. Ex-situ bioaccumulation studies demonstrated that sediment contamination did not correlate with bioaccumulation in Macoma nasuta, whereas porewater accurately reflected bioaccumulation trends. This study highlights the importance of considering stormwater discharge patterns and particle sizes when assessing sediment recontamination but also that the resulting bulk sediment contamination may not reflect bioavailability as measured by organism bioaccumulation. These insights contribute to a better understanding of the impacts of stormwater runoff on sediment and biota in southern California coastal watersheds, aiding in the development of effective management strategies.

Correction: Effect of the annealing temperature and of Bi substitution on the structural and magnetic behaviors of double-doping (Bi/La, Ca) (La0.8Ca0.2)1−xBixFeO3 compounds

Correction for ‘Effect of the annealing temperature and of Bi substitution on the structural and magnetic behaviors of double-doping (Bi/La, Ca) (La0.8Ca0.2)1−xBixFeO3 compounds’ by H. Issaoui et al., New J. Chem., 2020, 44, 9813–9821, https://doi.org/10.1039/D0NJ01962C.

Psychological impact of COVID19 outbreak and coping strategies among Tunisian medical students

Introduction

The COVID19 pandemic came with unprecedented measures that impacted every aspect of the student’s life making them vulnerable to psychological distress.

Objectives

The aim of this study was to assess anxiety and depressive symptoms in relation to the coping strategies during the COVID19 pandemic among medical students.

Methods

We conducted a web-based cross-sectional study among Tunisian medical students. We used an anonymous survey comprising sociodemographic characteristics, the Hospital Anxiety and Depression scale and the brief COPE.

Results

A total of 216 students participated in the study; 78% were female and most respondents were enrolled in first and second year of medical studies (53%). The frequency of depressive and anxiety symptoms were respectively 28% and 40%; females experienced significantly higher depression and anxiety scores (p<10¯³ and p=0.02 respectively). Most used coping strategies were self-blame, planning, acceptance, distraction, positive reframing, active coping and religion (99%-96%). The least used coping strategies were substance use (13%) and denial (52%). We found that gender was associated with a significant difference in the coping styles where females scored higher on religious coping and denial whereas males used more humor coping. Depression and anxiety were significantly associated with denial coping. Humor, acceptance, positive reframing and active coping were significantly associated with lower depression rates. Humor coping and active coping were associated with lower anxiety rates.

Conclusions

Our study shows alarming rates of depression and anxiety among Tunisian medical students during the COVID19 pandemic. A targeted intervention to promote mental health using the coping styles might be useful in this population.

Disclosure

No significant relationships.

Investigation of temperature and frequency dependence of the dielectric properties of multiferroic (La0.8Ca0.2)0.4Bi0.6FeO3 nanoparticles for energy storage application

The plot of dε′/dT versus temperature for the (La0.8Ca0.2)0.4Bi0.6FeO3 material proves four dielectric anomalies at 180 K, 240 K, 320 K and 350 K with a colossal dielectric constant at low frequency allowing its application in energy storage devices.

Structural, morphological, Raman, dielectric and electrical properties of La1-2x Ba x Bi x FeO3 (0.00 ≤ x ≤ 0.20) compounds

La_1-2x Ba _x Bi _x FeO₃ (0.00 ≤ x ≤ 0.20) nanoparticles were prepared by the auto-combustion method using glycine as a combustion fuel. X-ray diffractometry (XRD) measurements confirmed the orthorhombic structure of the synthesized compounds with the Pnma space group as a principal majority phase and showed the presence of a very minor secondary phase when x > 0.1. The nanosize criterion of the prepared compounds was confirmed from the crystallite size values calculated using the Williamson-Hall formalism. The relaxation process has been studied by the frequency dependence of the imaginary parts of impedance and modulus (Z'' and M'') which satisfied the Arrhenius law. Nyquist plots allowed us to obtain an adequate equivalent circuit involving the grains and grain boundary contributions. The activation energies calculated from Z'', M'' and the resistance of both contributions deduced from the Nyquist plots are found to be very similar. The conduction mechanism has been analyzed using the temperature dependence of the exponent Jonscher's power law parameter which confirms the NSPT conduction mechanism type for all compounds with an enhancement of the binding energy of the charge carrier (W _H) with the substitution.

Anxious driving behavior among taxi drivers

Introduction

The data suggest that anxious drivers may engage in problem behaviors that expose them and others to an increased risk of negative traffic events.

Objectives

To study the problematic behavior taxi drivers related to anxiety in three areas exaggerated safety/caution, performance deficits, and hostile/aggressive behaviors and to determine the factors who are associated with them.

Methods

This is a cross-sectional descriptive and analytical study of 58 taxi drivers in the city of Sfax, Tunisia. We used an anonymous questionnaire that included a socio-demographic fact sheet, and a driver behavior rating scale: Driver Behavior Survey (DBS) with 21 items.

Results

The mean age of the drivers was 40.8 ± 10.2 years. The sex ratio was 0.98. 75.9% were married. 6.9% lived alone. 53.4% were smokers and 25.9% drank alcohol. Coffee and tea consumption were 59% and 33% respectively. 67% had a pathological personal history, including osteoarticular pathologies. 17.2% had a history of serious accidents. The behavior related to anxiety among taxi drivers was 74.66 ± 13.35. The hostile behavior was 18.88 ± 8, the exaggerated safety behavior was 38.31 ± 7.3 and the deficit performance related to anxiety was 17.47 ± 7.1. The problematic behavior in our population was significantly associated with lifestyle alone, coffee consumption and with serious accidents.

Conclusions

The results of our study identified some risk factors that could lead to poorly adaptive driving behaviors among Taxi drivers. These elements reinforce us in the idea that this population requires special care with a meeting with the doctor.

The psychological impact of the COVID-19 pandemic and confinement period on a tunisian sample

Introduction

Coronavirus disease 2019, is now a global pandemic that has spread rapidly causing many deaths. Most countries have opted for compulsory confinement which had repercussions on mental health and well-being.

Objectives

The purpose of this study is to assess mental health consequences during the confinement period.

Methods

This is a cross-sectional descriptive study of 360 Tunisians in April and May 2020. We used an anonymous E-questionnaire that included a socio-demographic fact sheet, The HAD questionnaire, and a Q-EDD questionnaire to explore eating disorders.

Results

The subjects of our sample were mostly males with a mean age of 31. The body mass index was 25.5 (range 16.10 -46.24), 15% suffered from obesity. Half of the subjects were single and 6.7% spent the confinement time alone. 11.1% were smokers while 4.4% were alcohol users. The HAD-A and the HAD-D scores had an average of 9.1 and 8.48 respectively.A pathological threshold of anxiety and depression was found in 20% and 30% of the sample respectively.15% had an eating disorder: 76% had binge eating, 20% had bulimia and 17% had anorexia. In our study, we found an association between eating disorder and obesity, single marital status (p=0.007), living alone (p=0.001), history of depression (p=0.046), anxiety (p=0.049) and depression (p=0.038).

Conclusions

Reduced social interactions, decreased physical activity and increased stress are potentially harmful causes for our brain. Confining the population for several weeks has a negative impact on our physical and mental health. A crisis unit has been formed in Tunisia to help subjects overcome these psychological difficulties.

Pain perception in schizophrenia: A neglected phenomenon with a great impact

Introduction

A decrease in pain sensitivity has been observed in patients with schizophrenia since the beginning of the twentieth century. This hypothesis further emerged during the last decades due to many clinical findings.

Objectives

To study pain responsiveness in patients with schizophrenia and explore its physiopathological mechanism through a review of the literature.

Methods

We searched the Medline database with no time restrictions, and we hand searched the references of all retrieved reviews. After removing duplicates, we selected Full-text articles in both French and English languages. Keywords: “schizophrenia”, “pain”, “pain threshold”, “nociceptors”, “opioid receptors”, “opioid peptides”

Results

We have collected 399 references, we finally included 50 Articles only. Many case reports with heterogeneous types of pain concluded that despite the high prevalence of somatic comorbidities in patients with schizophrenia, there was no significant difference in pain complaints between patients with schizophrenia and controls. There was a positive correlation between the decrease in pain sensitivity and schizophrenia. Experimental studies supported a decrease in pain perception and a high pain threshold in those patients. The neurobiological hypothesis suggested the lack of pain transmission by the dysfunctional glutamatergic system and the involvement of the opioid system. these findings have been reported in patients even before starting treatment. The psychopathology theory pointed to the impact of psychotic defenses such as denial and cleavage in the phenomenon of pain insensitivity.

Conclusions

The meticulous research of pain symptoms should be systematic in patients with schizophrenia and the hypoalgesia should be considered when dealing with somatic conditions in this specific population.

When healing becomes a burden: The feedback of tunisian psychiatrists

Introduction

Psychiatry is a fascinating medical specialty. Many reasons may motivate early career doctors to choose this field. However, this experience could have a different impact on their quality of life and social functioning.

Objectives

we aimed to assess the impact of psychiatry as a medical career, on the psychiatrist’s quality of life, and to evaluate their feedback on their experience and how it effects their life.

Methods

This is a cross-sectional descriptive study of 68 psychiatrists. An E-questionnaire has been sent via a psychiatrist’s closed groups on social media. We collected sociodemographic data, we also used the stress perceived scale, and we explored the quality of life using the SF-12 questionnaire.

Results

The participants were mostly females with a mean age of 32 years (range25-65). Only 10% of psychiatrists had psychiatric history mostly depression. Concerning substance use, 15% were smokers, 17% used alcohol, 10% smoked occasionally cannabis and 23 % used different psychotropic drugs. 73% our sample were interested in psychiatry during their studies. 60% of our population considered the role of psychiatrists ambiguous among other colleagues. A very high perceived stress was noted in 90 % of our sample. Physical health status was in the average of standard deviation wether mental health status was below average among psychiatrists. The most frustrating situation mentioned was the absence of intermediate structures to receive psychotic patients.

Conclusions

Tunisians psychiatrists are facing many obstacles during the practice of their job, that would transform their passion into demotivation and a desire to leave the country.

Influence of film-thickness on the ozone detection of perovskite La0.8Pb0.1Ca0.1Fe1−xCoxO3 based sensors

In this study, La_0.8Pb_0.1Ca_0.1Fe_1−xCo_xO₃ (x = 0.10 and x = 0.20) thin films with respective thicknesses of 300 and 600 nm have been prepared by the drop coating technique onto a Si/SiO₂ substrate with platinum interdigitated electrodes.

Assessing Biota Accumulation Due to Contamination of Sediments by Storm Water Heavy Metals

Evaluating sediment recontamination due to storm water discharges is important when evaluating the long-term effectiveness of sediment remediation efforts at reducing biological impacts. The bioaccumulation of the heavy metals zinc, nickel, copper, cadmium, mercury, and lead and the metalloid arsenic in a clam (Macoma nasuta) was studied in surficial sediments before and after storm water inputs from Paleta Creek, California, USA, during wet seasons in 2015 to 2016 and 2016 to 2017. The bioaccumulation was compared with bulk sediment concentrations and porewater concentrations measured by diffusion gradient in thin film devices. Significant reductions in biota accumulation and porewater concentrations were observed in samples collected after storm seasons compared with before storm seasons despite bulk sediment concentrations remaining the same or increasing. This was apparently the result of the deposition of storm water contaminants in low bioavailable forms. The bioaccumulation of all the measured contaminants showed a positive significant correlation with porewater concentrations (p < 0.1, α = 0.1) and weak or no correlations with bulk sediment concentration. In conclusion, observed bulk sediment recontamination due to storm water should not be assumed to lead directly to greater biota accumulation without bioavailability assessment. Environ Toxicol Chem 2020;39:2475-2484. © 2020 SETAC.

Effect of Bi-substitution into the A-site of multiferroic La0.8Ca0.2FeO3 on structural, electrical and dielectric properties

(La_0.8Ca_0.2)_1-x Bi _x FeO₃ (x = 0.00, 0.05, 0.10, 0.15 and 0.20) (LCBFO) multiferroic compounds have been prepared by the sol-gel method and calcined at 800 °C. X-ray diffraction results have shown that all samples crystallise in the orthorhombic structure with the Pnma space group. Electrical and dielectric characterizations of the synthesized materials have been performed using complex impedance spectroscopy techniques in the frequency range from 100 Hz to 1 MHz and in a temperature range from 170 to 300 K. The ac-conductivity spectra have been analysed using Jonscher's power law σ(ω) = σ _dc + Aω ^s , where the power law exponent (s) increases with the temperature. The imaginary part of the complex impedance (Z'') was found to be frequency dependent and shows relaxation peaks that move towards higher frequencies with the increase of the temperature. The relaxation activation energy deduced from the Z'' vs. frequency plots was similar to the conduction activation energy obtained from the conductivity. Hence, the relaxation process and the conduction mechanism may be attributed to the same type of charge carriers. The Nyquist plots (Z'' vs. Z') at different temperatures revealed the appearance of two semi-circular arcs corresponding to grain and grain boundary contributions.

Effect of the annealing temperature and of Bi substitution on the structural and magnetic behaviors of double-doping (Bi/La, Ca) (La0.8Ca0.2)1−xBixFeO3 compounds

Perovskite (La_0.8Ca_0.2)_1−xBi_xFeO₃ compounds were synthesized by sol–gel method using the citric acid route and sintered at 800 °C and 900 °C. LCBFO 800 series has the smallest size of crystallites, a larger magnetization and a smaller Curie temperature.

Magnetocaloric study, critical behavior and spontaneous magnetization estimation in La0.6Ca0.3Sr0.1MnO3 perovskite

A detailed study of structural, magnetic and magnetocaloric properties of the polycrystalline manganite La_0.6Ca_0.3Sr_0.1MnO₃ is presented. The Rietveld refinement of X-ray diffraction pattern reveals that our sample is indexed in the orthorhombic structure with Pbnm space group. Magnetic measurements display a second order paramagnetic (PM)/ferromagnetic (FM) phase transition at Curie temperature T_c = 304 K. The magnetic entropy change (ΔS_M) is calculated using two different methods: Maxwell relations and Landau theory. An acceptable agreement between both data is noted, indicating the importance of magnetoelastic coupling and electron interaction in magnetocaloric effect (MCE) properties of La_0.6Ca_0.3Sr_0.1MnO₃. The maximum magnetic entropy change (−ΔS^max_M) and the relative cooling power (RCP) are found to be respectively 5.26 J kg⁻¹ K⁻¹ and 262.53 J kg⁻¹ for μ₀H = 5 T, making of this material a promising candidate for magnetic refrigeration application. The magnetic entropy curves are found to follow the universal law, confirming the existence of a second order PM/FM phase transition at T_c which is in excellent agreement with that already deduced from Banerjee criterion. The critical exponents are extracted from the field dependence of the magnetic entropy change. Their values are close to the 3D-Ising class. Scaling laws are obeyed, implying their reliability. The spontaneous magnetization values determined using the magnetic entropy change (ΔS_Mvs. M²) are in good agreement with those obtained from the classical extrapolation of Arrott curves (μ₀H/M vs. M²). The magnetic entropy change can be effectively used in studying the critical behavior and the spontaneous magnetization in manganites system.

A detailed investigation was conducted on the magnetocaloric properties of La_0.6Ca_0.3Sr_0.1MnO₃ and its potential application in cooling fields.

High prevalence of psoriatic arthritis in a cohort of patients with psoriasis seen in a dermatology practice

BACKGROUND/OBJECTIVES

The prevalence of psoriatic arthritis (PsA) is expected to range from 5 to 40% in individuals with psoriasis. The objective of this study was to quantify the prevalence of PsA in psoriasis patients seen in a dermatology practice and to define their characteristics using the validated Psoriatic Arthritis Screening Questionnaire (PASQ).

METHODS

Patients with definite plaque psoriasis (as determined by a dermatologist) completed the self-administered PASQ tool, and patients with a score ≥ 7 or ≥ 9 were assessed by a rheumatologist to ascertain the diagnosis of PsA according to the CASPAR (Classification Criteria for Psoriatic Arthritis) criteria.

RESULTS

Using a PASQ cutoff of 7, the estimated prevalence (95% CI) of PsA was 40.9% (29.0-52.8%), whereas a prevalence (95% CI) of 36.4% (24.8-48.0%) was estimated when a PASQ cutoff of 9 was used.

CONCLUSION

Our estimated prevalence of PsA in psoriasis patients from a population of patients drawn from a dermatology practice is greater than most previous estimates. This finding illustrates the importance of screening for PsA in psoriasis patients as this comorbidity may affect the course of treatment and, if left untreated, may have a profound effect on the disability and quality of life of a large number of psoriasis patients.

Influence of Ca-deficiency on the magneto-transport properties in La(0.8)Ca(0.2)MnO(3) perovskite and estimation of magnetic entropy change

La(0.8)Ca(0.2 - x)□(x)MnO(3) (x = 0.00, 0.10, and 0.20) perovskite was prepared by the conventional solid-state reaction and annealed at 1473 K. X-ray diffraction and scanning electron microscopy shown the existence of a secondary phase attributed to the unreacted Mn(3)O(4) oxide. The magneto transport properties have been investigated based on the temperature dependence of the resistivity ρ(T) measurements under several applied magnetic fields. We note that the La(0.8)Ca(0.2)MnO(3) (x = 0.00) sample has a classical metal-insulator transition at T(ρ). But we have observed that the lacunars samples (x = 0.10 and 0.20) include a metallic and insulator behavior simultaneously below T(ρ) and the resistivity is dominated by tunneling through the barriers associated with the insulating phase. In other words, the calcium deficiency favors the enhancement of the insulator behavior. The electrical resistivity is fitted with the phenomenological percolation model, which is based on the phase segregation of ferromagnetic metallic clusters and paramagnetic insulating regions. Furthermore, we found that the estimated results are in good agreement with experimental data. Above all, the resistivity dependence on the temperature and magnetic field data is used to deduce the magnetic entropy change. We have found that these magnetic entropy change values are similar to those calculated in our previous work from the magnetic measurements. Finally, we have found an excellent estimation of the magnetic entropy change based on the Landau theory.