Anionic Dye Removal with a Thin Cationic Polyaniline Coating on Cellulosic Biomaterial

This paper reports the development of novel adsorbent materials using polyaniline (PANI) grafted onto Posidonia (POS) fibers, aimed at efficiently removing phenol red (PSP), an anionic dye, from aqueous solutions. The synthesis involved the copolymerization of aniline grafted on the surface of the POS and aniline monomer in solution, resulting in a chemically bound thin PANI layer on the POS bioadsorbent. Structural characteristics and binding affinities of these adsorbents with PANI under its emeraldine salt (POS@PANI-ES) or emeraldine base (POS@PANI-EB) forms are reported. The rapid adsorption kinetics observed are attributed to enhanced accessibility to PANI adsorption sites on the POS surface. The binding percentages of PSP to POS@PANI-ES and POS@PANI-EB materials were found to be 97 and 50%, respectively, after 15 min of contact time. The Langmuir model for localized adsorption sites and the Volmer model for nonlocalized adsorption as a mobile layer were fitted to the experimental adsorption isotherms of PSP to POS@PANI-EB and POS@PANI-ES, yielding the thermodynamic parameters of adsorption. The adsorption capacities of PSP on POS@PANI-EB and POS@PANI-ES were 37.8 and 71.5 μmol g-1, respectively. The adsorption of PSP remained above 80% at moderate salt concentrations of around 0.1 mol L-1; however, higher concentrations of NaCl and CaCl2 in PSP solutions significantly reduced the adsorption on POS@PANI-ES.

Versatile anti-infective properties of pyrido- and dihydropyrido[2,3-d]pyrimidine-based compounds

A series of 1H-indeno[2',1':5,6]dihydropyrido[2,3-d]pyrimidine and 1H-indeno[2',1':5,6]pyrido[2,3-d]pyrimidine derivatives was prepared and screened for antiparasitic and viral RNase H inhibitory activity. Several compounds showed considerable activity against Toxoplasma gondii parasites and Leishmania major amastigotes, which warrants further investigation. Based on the structural similarities of certain derivatives with common viral RNase H inhibitors, a HIV-1 RNase H assay was used to study the RNase H inhibition by selected test compounds. Docking of active derivatives into the active site of the HIV-1 RNase H enzyme was carried out. The new compound 2a, inactive in the antiparasitic tests, showed distinct HIV-1 RNase H inhibition. Thus, ring substitution determines antiparasitic or HIV-1 RNase H inhibitory activity of this promising compound class.

Low-cost Posidonia oceanica bio-adsorbent for efficient removal of antibiotic oxytetracycline from water

The presence of antibiotics as micro-contaminants in the water and aqueous environments is a health concern to humans and the ecosystem. Therefore, their elimination by adsorption to available and cheap materials in water treatment plants is a research topic of high relevance. The present paper reports on the adsorption behavior of oxytetracycline on a bio-adsorbent prepared from Posidonia oceanica; an abundant Mediterranean biomass. Characterization of the pretreated Posidonia biomaterial was achieved using several analyses such as Boehm acid-base titration method, pH_PZC determination, and analysis techniques (FTIR, ¹³C CP-MAS NMR, optical microscopy, and TGA). The pH_PZC occurred around pH 2.11. Posidonia biomaterial showed a fast and high uptake rate throughout the adsorption process, which is a definite advantage for analytical applications such as water decontamination. The experimental kinetic data fitted very rightly the pseudo-second-order kinetic model and the equilibrium uptake can adopt the bi-Langmuir isotherm model for all studied pH values which assumes adsorptions at the two localized sites. Maximum adsorption capacities of 11.8 mg∙g^-1 and 4.4 mg∙g^-1 for the two adsorption sites are reached at pH 6. The oxytetracycline adsorption process onto Posidonia bio-adsorbent is spontaneous (Δ_adsG⁰ < 0), exothermic (Δ_adsH⁰ < 0), and entropically favorable (Δ_adsS⁰ > 0). The effect of pH on adsorption behavior and the thermodynamic parameters of adsorption are consistent with a possible origin of adsorption of oxytetracycline by means of hydrogen bonding interactions between surface hydroxyl and phenolic groups of the biomaterial and oxytetracycline. The proposed green and environmentally friendly biomaterial offers potential benefits as a bio-adsorbent in the remediation of aquatic environments contaminated by various organic materials.

Development of metal hydroxide nanoparticles from eggshell waste and seawater and their application as flame retardants for ethylene-vinyl acetate copolymer (EVA)

Recently, calcium hydroxide and magnesium hydroxide nanoparticles have attracted a lot of research interest in different sectors: food, packaging, health, automotive construction and food application. In the present study, we report development of bio-material calcium hydroxide nanoparticles (Ceg-Ca(OH)₂), obtained from chicken eggshell collected from the food industries as well as magnesium hydroxide nanoparticles obtained from seawater (Seaw-Mg(OH)₂). The flame-retardant behavior of Ethylene-Vinyl Acetate copolymer (EVA) containing different blends of Ceg-Ca(OH)₂ and Seaw-Mg(OH)₂ nanoparticles has been evaluated using cone calorimeter. Our results showed the interest of combining both nanoparticles. In fact, the partial substitution of small Seaw-Mg(OH)₂ content (10 wt%) by Ceg-Ca(OH)₂ enables further reduction of pHRR from 251 to 206 kW/m² without any reduction of the composite time to ignition (52 s). Furthermore, the partial substitution of 40 wt% Seaw-Mg(OH)₂ nanoparticles by Ceg-Ca(OH)₂ enables high flame retardant effect as well as the generation of cohesive residue.

Synthesis and Structural, Electrical, and Magnetic Properties of New Iron-Aluminum Alluaudite Phases β-Na2Ni2M(PO4)3 (M = Fe and Al)

Herein we report the studies of different physical properties (structural, magnetic, thermal, morphologic, electrical, and electrochemical) of two new allotropic β-Na₂Ni₂M(PO₄)₃ (NNMP) phosphates, with M = Fe and Al. Pure orthorhombic single-phase powders were prepared under air, using an autocombustion synthesis method. They crystallize in the orthorhombic Imma space group with similar unit cell parameters [a = 10.1592(2), b = 13.0321(3), c = 6.4864(2) Å] and [a = 10.3993(1), b = 13.1966(1), c = 6.4955(1) Å] for β-Na₂Ni₂M(PO₄)₃ (NNAP) and β-Na₂Ni₂Fe(PO₄)₃ (NNFP), respectively. Crystal structures of both compounds were determined using X-ray powder diffraction and Rietveld method refinements, which indicate the occurrence of Ni²⁺ in the 8g site, and of M³⁺ in the 4a site of the structure. The structure consists of a three-dimensional anionic framework obtained by the association on MO₆, NiO₆, and PO₄ polyhedra, sharing edges and corners. The resulting three-dimensional structure creates monodimensional channels along the [100] and [010] directions formed by face-shared oxygen polyhedra and occupied by Na⁺ cations. This nondisordered cationic distribution is confirmed by a significant change of magnetic properties. Thus, both NNAP and NNFP samples show paramagnetic to ferromagnetic transition at 14 and 19 K, respectively. For the two compounds, thermal stability, electrical conductivity, and electrochemical properties have been also investigated. The intercalation/desintercalation properties of NNMP compounds as positive electrode were tested in sodium-ion batteries. The first cycling curves exhibit a significant polarization for both prepared samples.

Interfacial properties and thermodynamic behavior of cationic amphiphilic β-cyclodextrins substituted with one or seven alkyl chains

New cationic amphiphilic β-cyclodextrins (β-CD) were investigated for their surface-active properties and self-association.

[Value of procalcitonin measurement in maternal fetal infection]

BACKGROUND

Materno foetal infection (MFI) remains one of the major causes of neonatal morbidity and mortality. Early detection of neonatal sepsis can be difficult, because the first signs of the disease may be unspecific and similar to symptoms of other non-infectious processes.

AIM

We aimed to investigate the role of procalcitonin (PCT) in the diagnosis of fetal infection (MFI), and to compare it with those of the C-reactive protein (CRP).

METHODS

We have conducted a prospective study during 20 months: which concerned 25 newborns suspected of MFI and admitted before 12 hours of life. All newborn had anamnestic and/or physical signs of possible infection. MFI was confirmed in newborns with positive bacterial analysis. CRP and PCT were determined in the sera at H12, H24, H36 and H48. Newborns were divided into: patients with recognized MFI (group 1), patients with possible MFI (group2) and non infected newborns (group 3):

RESULTS

The specificity of PCT was 80% versus 27% for the CRP. Negative predictive value of PCT was 85% versus 66% for the CRP. The mean values, at H12, H24, H36 and H48, of PCT for newborn who had MFI were statistically grater than those for no infused group (p<0.05). No statistical difference was observed concerning CRP values.

CONCLUSIONS

PCT may a useful tool in early diagnosing of MFI; it has better specificity and negative predictive value than CRP.

[Atypical presentation of Wegener disease in childhood]

The pediatric forms of Wegener granulomatosis (WG) are rare. The clinical picture and the profile have specificities compared to those of adults. We report a case of a girl aged of four years and a half who presented initially with a clinical picture of Henoch Schönlein purpura. Physical examination revealed additionally to purpura, scabby lesions on the buttocks. The histopathological examination of a skin biopsy disclosed histiocyte infiltration. There were no Ig A deposits on direct immunofluorescence study. One year later, the diagnosis of WG was suspected, when the patient developed a respiratory problem related to left pulmonary infarction. Screening for thromboembolic factors was positive for antiphosphilipid antibodies. Diagnosis of WG was confirmed by the histopathological study lung tissue and a significant titre of serum ANCA. Blood tests failed to provide evidence of renal involvement. Cyclophosphamide and prednisolone therapy was administrated. A relapse occurred one year later on the controlateral lung; but no biological marker of disease activity could be detected.

[Clinical and etiological features of primary adrenal insufficiencies in children]

BACKGROUND

The chronic primary adrenal insufficiency or Addison's disease is uncommon in children and belongs generally to a complex syndrome.

AIM

Study of the clinical and aetiological features of primary adrenal insufficiencies in children.

METHODS

In a retrospective study, we reviewed clinical and diagnostic data of all cases of Addison's disease admitted within a period of 15 years (from january 1991 to December 2006), in a department of paediatrics. Cases due to congenital adrenal hyperplasia were excluded.

RESULTS

6 cases of Addison's disease were diagnosed. Five patients are the product of consanguineous marriage. The age at the diagnosis of adrenal insufficiency varried from 15 months to 9 years 8 months. The adrenal insufficiency was associated to Allgrove syndrome in three cases, to autoimmune polyendocrinopathy type 1 in one patient and to probable peroxisomal disease in another one. The etiological disease was not determined in one patient. A substitutive hormonal therapy was conducted in all patients. During a mean follow-up of 26 months, two adrenal crises were noted.

CONCLUSION

Larger studies about Addison's disease are needed to confirm the preponderance of the Allgrove syndrome.