Investigation of structural, optical and electrical conductivity of a new organic inorganic bromide: [C12H17N2]2ZnBr4

A new organic-inorganic hybrid, namely the [C₁₂H₁₇N₂]₂ZnBr₄ compound, has been synthesized and studied by single-crystal X-ray diffraction and optical and complex impedance spectroscopy. It crystallized in the centrosymmetric P2₁/n space group at room temperature. The asymmetric unit is constituted by [ZnBr₄]^2- anions, showing slightly distorted tetrahedral geometry, surrounded by four organic (C₁₂H₁₇N₂)⁺ cations. The crystal packing is stabilized by N-H⋯Br and C-H⋯Br hydrogen bonds arranged in a three-dimensional network. The optical absorption measurement confirms the semiconductor nature with a band gap of around 3.94 eV. Additionally, the analysis of Nyquist plots (-Z'' vs. Z') shows that the electrical properties of the material are heavily dependent on frequency and temperature, indicating a relaxation phenomenon and semiconductor-type behavior. Reduction in Z' was observed as a function of temperature and frequency which indicates an increase in ac conductivity and the negative temperature coefficient of resistance. The frequency dependent plots of (-Z'') show that the electrical relaxation is non-Debye in nature. The ac conductivity spectrum obeys Jonscher's universal power law. The Correlated barrier hopping model CBH has been suggested to agree with the conduction mechanism of σ _ac for the [C₁₂H₁₇N₂]₂ZnBr₄ compound.

Synthesis, structural and electrical characterization of a new organic inorganic bromide: [(C3H7)4N]2CoBr4

A new organic inorganic hybrid [TPA]2CoBr4, where TPA = [(C3H7)4N]+ (i.e., tetra-propyl-ammonium) compound has been synthesized by slow evaporation method at room temperature. Single crystal X-ray diffraction (SC-XRD), X-ray powder diffraction (XRPD), thermal analyses, vibrational and complex impedance spectroscopy have been used to characterize both structural, thermal, electrical properties. [TPA]2CoBr4 crystallizes in the monoclinic system (C2/c space group) with the following cell parameters: a = 33.145 (5) Å, b = 14.234 (3) Å, c = 15.081 (2) Å and β = 110.207 (5)°. In the crystal structure, the organic TPA cations which form layers stacked along the a-axis, are separated from each other by inorganic tetrahedral [CoBr4]2- anions. The XRPD pattern confirms both the high purity of the sample and the crystalline nature of the powder. The differential scanning calorimetry (DSC) analysis shows an endothermic peak at 394 K upon heating which is ascribed to a structural phase transition since no decomposition of the titled compound is evidenced by thermogravimetric analysis. The ac conductivity and the dielectric properties confirm the presence of the phase transition. At the structural phase transition around 394 K, a change from a quantum mechanical tunneling to a correlated barrier hopping conduction models is determined from the temperature dependence of the exponent s of the Jonscher's power law. The analysis of complex impedance spectra shows that the electrical properties of the material are heavily dependent on frequency and temperature, indicating a relaxation phenomenon and semiconductor-type behavior. One single semicircle is detectable in the Nyquist plots of the complex impedance spectra which can be satisfactorily fitted with a combination R//CPE elements assigned to the bulk response. This behavior suggests that the sample is electrically homogeneous. Capacitance analysis proves the high effective permittivity at radio frequencies in the sample.

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Antibiotics are one of the greatest advances in modern medicine. Antibiotic resistance is one of the most serious threats to global health, aggravating the prognosis of immunocompromised patients, especially burn patients. Our objective was to study the consumption of antibiotics of critical importance according to the WHO and the correlation between antibiotic resistance in Pseudomonas æruginosa and the consumption of these antibiotics. Our study took place in the Medical Laboratory in collaboration with the Trauma and Burn Center's Burn Unit in Tunisia. In our retrospective study, 1384 non-repetitive strains of Pseudomonas æruginosa responsible for colonization or infection were included, between January 2012 and December 2019. Pseudomonas æruginosa was the most isolated bacterial strain in the service, with an average rate of 15.9% of the service's bacterial ecology. The antibiotic resistance rates tested were high: 77.1% to piperacillin-tazobactam, 56% to ceftazidime, 74.9% to imipenem, 78.8% to amikacin, 54.7% to ciprofloxacin and 32.8% to fosfomycin. Among our strains, 81.8% were multi drug-resistant strains. The analysis of the correlation between the level of consumption of antibiotics and the antibiotic resistance levels in Pseudomonas æruginosa showed that the increased consumption of piperacillin-tazobactam increased resistance not only to piperacillin-tazobactam but also to imipenem and amikacin as well as multi drug resistance. Similarly, the increase in the consumption of fosfomycin correlates with resistance to piperacillin-tazobactam and imipenem.

Anakinra in hospitalized patients with severe COVID-19 pneumonia requiring oxygen therapy: Results of a prospective, open-label, interventional study

Objective

The aim of this study was to evaluate the efficacy of anakinra in patients who were admitted to hospital for severe COVID-19 pneumonia requiring oxygen therapy.

Methods

A prospective, open-label, interventional study in adults hospitalized with severe COVID-19 pneumonia was conducted. Patients in the interventional arm received subcutaneous anakinra (100 mg twice daily for 3 days, followed by 100 mg daily for 7 days) in addition to standard treatment. Main outcomes were the need for mechanical ventilation and in-hospital death. Secondary outcomes included successful weaning from supplemental oxygen and change in inflammatory biomarkers. Outcomes were compared with those of historical controls who had received standard treatment and supportive care.

Results

A total of 69 patients were included: 45 treated with anakinra and 24 historical controls. A need for mechanical ventilation occurred in 14 (31%) of the anakinra-treated group and 18 (75%) of the historical cohort (p < 0.001). In-hospital death occurred in 13 (29%) of the anakinra-treated group and 11 (46%) of the historical cohort (p = 0.082). Successful weaning from supplemental oxygen to ambient air was attained in 25 (63%) of the anakinra-treated group compared with 6 (27%) of the historical cohort (p = 0.008). Patients who received anakinra showed a significant reduction in inflammatory biomarkers.

Conclusion

In patients with severe COVID-19 pneumonia and high oxygen requirement, anakinra could represent an effective treatment option and may confer clinical benefit.

Trial registration number

ISRCTN74727214.

Protective effects of spirulina against hemato-biochemical alterations, nephrotoxicity, and DNA damage upon lead exposition

The current study was aimed at exploring the protective efficacy of spirulina against the hemato-biochemical alterations and nephrotoxicity induced by lead (Pb). Female rats aged 12 weeks were treated for 4 weeks with Pb (0.344 g kg^-1 bw) associated or not with spirulina (5.3 g kg^-1 bw). Renal damage induced by Pb was related to a severe anemia, increases of oxidative stress-related parameters (thiobarbituric acid reactive substances (TBARS) (+29%), protein carbonyl (PCO) (+66.3%), and advanced oxidation protein product (AOPP) (+110%)), plasma lactate dehydrogenase (LDH) (+80%), creatinine and urea levels in plasma, and uric acid concentration in urine, as well as genotoxic changes (+89.3% and +60% for DNA and mRNA levels, respectively). Conversely, LDH and antioxidant enzyme activities in kidney were decreased, as well as the levels of plasma uric acid, and urinary creatinine and urea levels. Spirulina-supplemented rats exhibited normal peripheral blood and renal parameters and renal histology. It can be suggested that Arthrospira platensis alleviates damages induced by Pb, thanks to its high phenolic content and antioxidant capacity.

Electrical conductivity and vibrational studies induced phase transitions in [(C2H5)4N]FeCl4

The compound, tetraethylammonium tetrachloroferrate [(C₂H₅)₄N]FeCl₄, was prepared by slow evaporation at room temperature. It was characterized by X-ray powder diffraction, thermal analysis, and impedance and vibrational spectroscopy. X-ray diffraction data confirmed formation of a single phase material which crystallized at room temperature in the hexagonal system (P6₃ mc space group). DSC showed the existence of two phase transitions at 413 K and 430 K. Electrical conductivity was measured in the temperature and frequency ranges of 390 K to 440 K and 40 Hz to 110 MHz, respectively. Nyquist plots revealed the existence of grains and grain boundaries that were fitted to an equivalent circuit. AC conductivity plots were analyzed by Jonscher's power law. Variations in the "s" values indicated that CBH models describe the conduction mechanism in regions I and II. Temperature dependence of Raman spectra showed that the most important changes were observed in the cationic parts ([(C₂H₅)₄N]⁺). The activation energy value obtained from the line width decreased which indicated an order-disorder model.

Spirulina exhibits hepatoprotective effects against lead induced oxidative injury in newborn rats

Lead is a toxic metal that induces a wide range of biochemical and physiological effects. The present investigation was designed at evaluating the toxic effects of a prenatal exposure to lead of mothers on hepatic tissue of newborn rats, and potent protective effects of spirulina. Female rats were randomly divided into 4 groups which were given a normal diet (control),a diet enriched with spirulina (S), lead acetate administered through drinking water (Pb), or a diet enriched with spirulina and lead contaminated water (S Pb), respectively. The duration of treatments was from the 5th day of gestation to 14 days postpartum. Lead toxicity was assessed by measuring body and liver weights, blood and stomach lead levels, hepatic DNA, RNA and protein amounts, blood enzyme activities (AST and ALT), as well as lipid peroxidation level and activities of antioxidant enzymes in hepatic tissues of neonates. Lead intoxication of mothers caused reduction of liver weight as well as of hepatic DNA, mRNA and protein levels in newborns. Moreover, oxidative stress and changes in antioxidant enzyme activities were recorded. Conversely, supplementation of mothers with spirulina mitigated these effects induced by lead. These results substantiated the potential hepatoprotective and antioxidant activity of spirulina.

Electrical properties, conduction mechanism and modulus of diphosphate compounds

Rubidium aluminium diphosphate was synthesized by a conventional solid-state technique and its conduction properties determined by impedance spectroscopy.

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.

Polarized Raman study of [N(C3H7)4]2Cd2Cl6 single crystal

Chemical preparation, mid-infrared and Raman spectra of [N(C(3)H(7))(4)](2)Cd(2)Cl(6) are presented. Polarized Raman spectra of oriented single crystals have been recorded in the range 7-3900 cm(-1) under various polarization configurations with regard to the symmetry and the numbers of several band modes observed in the Raman and infrared spectra. The obtained results are consistent with the theoretical predictions based on the infrared and Raman selection rules.

Optimization of a New Non-viral Vector for Transfection: Eudragit Nanoparticles for the Delivery of a DNA Plasmid

The development of new vectors to deliver DNA into cells for therapy of cancers or genetic diseases has been a major area of research for many years. However, the clinical application of this technology requires the development of efficient, reliable and sterile vectors enabling the transfer of genes in vivo. Non viral, polymer or lipid-based vectors offer a new impetus to gene therapy because they are less toxic than viral vectors (no endogenous recombination, fewer immunological reactions, easy production and delivery of large-sized plasmid). The aim of this study is to develop a new tool for DNA delivery composed of methacrylic polymeric (Eudragit® RS and RL) nanoparticles. These nanoparticles were prepared by two methods: nanoprecipitation and double emulsion. The nanoparticles were characterized by their size, zeta potential and amount of DNA adsorption. Cytotoxicity tests based on mitochondrial activity (MTT test) revealed that the nanoparticles had limited cytotoxicity and that this depended on both the cell type and the nanoparticle concentration. Transgene expression was observed using the Green Fluorescence Protein gene as reporter gene, and was evaluated by flow cytometry in FaDu, MDA-MB 231 and MCF-7 cell lines. The results showed that transfection rates ranging between 4 and 7% were achieved in FaDu and MDA-MB 231 cells with nanoparticles prepared by the nanoprecipitation method. In MCF-7 cells transfected with nanoparticles prepared by either the double emulsion or the nanoprecipitation method, the transfection efficiency was between 2 and 4%. Nanoparticles prepared by nanoprecipitation were slightly more efficient than nanoparticles prepared from a double emulsion. Particle size was not an important factor for transfection, since no significant difference was observed with size between 50 and 350 nm. We showed that Eudragit® RS and RL nanoparticles could introduce the transgene into different types of cells, but were generally less effective than the lipofectamine control.

Use of Geotrichum candidum for olive mill wastewater treatment in submerged and static culture

The production of lignin peroxidase (LiP), manganese peroxidase (MnP) and lipases by Geotrichum candidum were performed in order to control the decolourisation and biodegradation of olive mill wastewater (OMW). Optimisation of different factors showed that dilution, carbon and ammonium concentrations significantly affected decolourisation and activities of ligniolytic peroxidases (LiP and MnP) on OMW. Moreover, addition of olive oil and agitation improved the lipase production. Batch and continuous OMW treatments in settler or bubble column bioreactors showed high COD and colour removal efficiencies of 60% and 50%, respectively. Lipolytic activity was greater in the batch bubble column whereas, LiP and MnP productions were improved in the settler. The performance of the continuous processes decreased with the decrease of hydraulic retention time (HRT). It has been shown that decolourisation and biodegradation decreased with an average of 40% and 45%, respectively, by decreasing the HRT from 4d to 1.7d.

Paratesticular angiomyofibroblastoma: case report and review of the literature

Angiomyofibroblastoma is a rare, benign, mesenchymal tumour occurring mainly in the female genital tract, and more rarely, in males. We present a new case of angiomyofibroblastoma arising in the left inguinal region of an 83-year-old man. The tumour was well circumscribed and measured 60 mm in maximum dimension. On microscopic examination, the tumour was composed of small spindle cells without atypia within a fibrous and myxoid stroma where scattered mononuclear inflammatory cells were found around the capillaries of the stroma. Immunohistochemical studies showed positive staining of tumour cells for vimentin, desmin, smooth muscle actin and CD34, and negative staining for PS100 and oestrogen and progesterone receptors. These histological findings are consistent with angiomyofibroblastoma. The patient was followed up for 4 years without recurrence.

Vibrational study of [(CH3)4N]2Cu0.5Zn0.5Cl4

[(CH3)4N]2Zn0.5Cu0.5Cl4 shows an orthorhombic system at ambient temperature with P2(1)nb space group. At room temperature, the crystal consists of three sublattices constituted by MCl4 (M=Cu and Zn) and two tetramethylammoniums N1(CH3)4 and N2(CH3)4, which give rise to a total of 372 vibrational modes that transform according to the four irreductible representations of the C2v point group in the following way: Gamma(vib)=93(A1+A2+B1+B2). The infrared and Raman spectra of polycrystalline samples have been investigated at room temperature. The assignment of the observed bands is discussed.

The kinetic behaviour of a two-enzyme system in biphasic media: coupling hydrolysis and lipoxygenation

Analysis of the kinetic behaviour of a two-enzyme-system carrying out two consecutive reactions was investigated in macroheterogeneous biphasic media (octane/buffer pH 9.6, v/v = 1:1). The lipase-catalysed hydrolysis of trilinolein and the subsequent lipoxygenation of the liberated linoleic acid, were coupled in a modified Lewis cell with a well-defined liquid/liquid interfacial area. Trilinolein was dissolved in the organic phase and hydrolysed in the presence of Mucor javanicus lipase at the organic/aqueous interface. Linoleic acid, liberated after hydrolysis was transferred to the aqueous phase and reacted with lipoxygenase. This reaction consumed linoleic acid and produced hydroperoxides, which favoured the transfer of residual linoleic acid, since they possess surface active properties. Catalysis and transfer influenced each other reciprocally. At low substrate concentrations, cooperativity phenomena were observed in the experimental and also the modelled two-enzyme systems. When the initial substrate concentration was high, the kinetic behaviour of the two-enzyme system in a compartmentalised medium, seemed to be independent of the substrate concentration, unlike that observed in homogeneous monophasic enzymology. The numerical integration program used to model the two-enzyme system was based on results obtained in separate studies of the following three phenomena: (1) trilinolein hydrolysis in biphasic medium. (2) linoleic acid transfer across a liquid/liquid interface and (3) lipoxygenation in an aqueous media. Results obtained by modelling were similar to the results observed experimentally.

Percutaneous treatment of hydatid cysts (Echinococcus granulosus)

A new method called PAIR (Puncture-Aspiration of cyst contents--Injection of hypertonic saline solution--Reaspiration) was used as a percutaneous treatment of hydatid cysts. In 37 patients, 120 cysts were punctured. All patients had not been considered surgical candidates. The cysts were localized in the liver, peritoneum, spleen, kidneys, muscles, and bones. In 70% of patients, good results were obtained. Recurrence occurred in 5 of 120 cysts, all at the beginning of our experience when a low concentration of sodium chloride solution was injected. Moderate allergic reactions occurred during seven cyst aspirations. No anaphylactic shock, sudden deaths or dissemination of cyst contents were observed.

[Primary, exclusively gastric localization of alpha-chain disease: anatomo-clinical and immunohistochemical study]

We report the first case of heavy alpha-chain disease exclusively located in the stomach and in the perigastric nodes in a thirty year old Tunisian patient. Both the small bowel and the mesenteric nodes were evaluated histologically and immunochemically and were found to be free of disease. Complete remission was obtained using chemotherapy. The reasons for which the small intestinal mucosa and the mesenteric nodes, nearly constantly involved, in alpha-chain disease were spared in our case, are discussed.