Crystal structure, optical characterization, conduction and relaxation mechanisms of a new hybrid compound (C6H9N2)2[Sb2Cl8]

Hybrid materials play a crucial role in the construction of flexible electronic devices due to the advantages of both organic and inorganic components. To this end, a new hybrid compound (C6H9N2)2[Sb2Cl8] was successfully fabricated using the slow evaporation solution growth approach at room temperature. In-depth research has been done on the structural, optical, and dielectric characteristics. This compound adopts the triclinic symmetry and crystallizes in the centrosymmetric space group P1̄. The inorganic and organic components respectively form anionic and cationic layers parallel to the ac-plane and alternate along the crystallographic b-axis. The [Sb2Cl8]2- dimeric units are bound to the 2-amino-5-picolinium cations [(C6H9N2)]+ through N-H⋯Cl hydrogen bonds. Optical absorption measurements showed a semiconductor behavior with a band gap of approximately 3.57 eV. In addition, DFT calculations were performed to investigate the absorption spectrum, wavelength, and HOMO-LUMO gap. The analysis of complex impedance spectra shows that the electrical conductivity of the sample is strongly frequency and temperature dependent, indicating a relaxation phenomenon and semiconductor-type behavior. Dielectric data obtained from complex impedance spectroscopy and ac conductivity with the use of the Maxwell-Wagner equivalent circuit model, and the universal power law have been investigated to explore the basic components of the electronic transport and relaxation process in our material.

Sternoclavicular septic arthritis in a healthy adult: A case report and a review of the literature

Sternoclavicular joint septic arthritis is rare and commonly associated with specific risk factors. We report the case of a 58-year-old female with no previous medical or surgical history who presented complaining of a warm, indurated mass overlying the right sternoclavicular joint. Computed tomography of the chest showed erosion of the sternal end of the clavicle and the manubrium sternum associated with thickening of the synovium and a sternoclavicular joint space narrowing, suggestive of an infective process. Intraoperative finds a purulent collection extending both over the clavicle and the sternum. Limited destruction of small parts of the sternoclavicular joint was noted. The abscess was drained. Simple debridement and limited curettage were preferred to en bloc resection given the limited size of necrotic tissues. Sternoclavicular joint septic arthritis is a condition with significant morbidity and potential mortality. All medical practitioners must maintain a high degree of suspicion, even in healthy patients, as it can lead to serious complications.

Diagnostic et prise en charge de la fibrose post-COVID

Introduction

La prévalence de la fibrose post-COVID est variable selon les études et sa physiopathologie est encore mal connue. On se propose à travers cette étude de décrire le profil clinique et radiologique des patients ayant développé cette complication suite à une pneumopathie à SARS-CoV-2.

Méthodes

Il s’agit d’une étude prospective, menée auprès des patients hospitalisés pour une pneumopathie à SARS-CoV-2 durant la période allant de septembre 2020 à mars 2021, au CHU Mohamed Taher Maamouri Nabeul et qui ont revus à la consultation de suivi à 1 mois et 3 mois.

Résultats

Deux cent soixante-dix-neuf patients ont été inclus, 161 étaient des hommes avec un sex-ratio à 1,35. L’âge moyen était de 64,9 ans. Les comorbidités les plus fréquentes étaient l’obésité (44,2 %), le diabète (43,5 %) et l’HTA (54,3 %). Les antécédents respiratoires n’étaient retrouvés que chez 46 patients (16,6 %) : asthme dans 3,2 % des cas, BPCO dans 4,3 % et DDB dans 1,8 %. Les symptômes persistants à 3 mois étaient : une dyspnée dans 15,4 % des cas, une toux sèche dans 3,6 % des cas. Les patients encore symptomatiques à 3 mois étaient essentiellement des hommes (38 hommes/19 femmes) de 66 ans d’âge moyen. Parmi eux, 27 avaient un besoin en oxygène initial > 6 L (p = 0,703) ; la majorité avait des lésions étendues (> 25 %) et 12 avaient séjourné en réanimation. La TDM thoracique à 3 mois, faite chez 78 patients (28 %), a objectivé des anomalies persistantes à type de verre dépoli et/ou de condensations parenchymateuses dans 21 cas et des stigmates de fibrose pulmonaire (à type de réticulations, un épaississement des lignes septales, une distorsion bronchique à type de rayon de miel ou de bronchiectasies par traction) chez 18 patients. Un bilan immunologique fait chez les patients avec signes tomodensitométriques de fibrose, revenu positif chez 5 patients. Un bilan fonctionnel respiratoire a été pratiqué 20 les patients encore dyspnéiques à 3 mois et ayant gardé des anomalies scanographiques parenchymateuses. La pléthysmographie a objectivé un syndrome restrictif chez 5 patients et le test de marche 6 min, une désaturation chez 9 patients. Le diagnostic de fibrose post-COVID avec retentissement respiratoire a été retenu chez 10 patients chez lesquels on a entamé une corticothérapie à raison de 0,5 mg/kg/j équivalent prednisone selon le protocole SPLF.

Conclusion

La fibrose post-COVID serait associée aux formes sévères de la pneumopathie COVID-19 avec des lésions parenchymateuses étendues.

Monitoring dehydration of the organic-inorganic [(C3H7)4N][SnCl5(H2O)]·2H2O compound using simultaneous thermal and Raman studies

In this work we report the experimental studies of the structural phase transition in the [(C3H7)4N]SnCl5(H2O)]·2H2O compound by differential scanning calorimetric (DSC) and Raman spectroscopic. The X-ray powder diffraction study of the [(C3H7)4N][SnCl5(H2O)]·2H2O sample at room temperature showed that this compound is monoclinic and has P121/c1 space group. Differential scanning calorimetric disclosed two types of phase transitions in the temperature range 356-376 (T1) K and at 393K (T2) characterized, by a loss of water molecules and probably a reconstruction of new anionic parts after T2 transition. The Raman scattering spectra recorded at various temperatures in the wavenumber range from 100 to 3800cm(-1) covering the domains of existence of changes in the vicinity of the two phase transitions detected by DSC measurement. A detailed study of the spectral parameters (wave number, reduced intensity and the full width at half maximum) as a function of temperature of a chosen band, associated with (νs(SnO)+νs(SnCl)), based on an order-disorder model allowed us to obtain information relative to the activation energy and correlation length.

Using Raman spectroscopy to understand the origin of the phase transitions observed in [(C₃H₇)₄N]₂Zn₂Cl₆ compound

Phase transitions of the centrosymmetric compound, [(C3H7)4N]2Zn2Cl6, were studied by differential scanning calorimetry (DSC), X-ray diffraction, Raman spectroscopy and dielectric measurements. Two reversible order-disorder and displacive phase transitions are observed at T1=327K and T2=347K with 3K and 4K hysteresis respectively, indicating a first order character. The evolution of Raman line shifts, "ν", and the half-width, "Δν", versus temperature show some singularities associated with the transitions, suggesting that they are governed by the reorientational and the displacement of the organic part. Besides the results of the dielectric permittivity study confirms the conclusion drawn from the calorimetric and Raman measurements that the phase transition located in the vicinity of the temperature of the dielectric proprieties is characterized by change of dynamical state of cation.