Ba(H2PO3)2.0.5H2O: Synthesis, crystal structure optimization, vibrational study, DFT computation and application as a corrosion inhibitor

This investigation involved the synthesis of barium phosphite Ba(H2PO3)2.0.5H2O by reacting barium chloride with phosphorous acid. The physical characteristics, FT-IR spectra, and X-ray diffraction were employed to validate the composition of the synthesized substance, and powder X-ray diffraction (PXRD) was used to determine the phase purity. The optimal molecular geometry, infrared intensities were calculated using density functional theory (DFT/B3LYP) methods with the LanL2DZ basis set. The HOMO-LUMO properties and geometries of this compound have been determined and discussed. The computational structural parameters are generally in agreement with the experimental investigations. The theoretical infrared for the title compound has been constructed. Additionally, the anti-corrosion properties of this compound were investigated in an acidic solution using weight loss and electrochemical techniques. The results showed good effectiveness, indicating the formation of a protective film on the C38 surface

Removal of methylene blue with a highly effective hydroxyapatite-silica nanocomposite

Two Hydroxyapatite-silica nanocomposite adsorbent (HApS220 and HApS230) were successfully synthesized using sol-gel technique. The samples were characterized by powder X-ray diffraction (XRD), Infrared spectroscopy (IR), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), which confirmed the formation of a Hydroxyapatite-silica nanocomposite. The synthesized powders were then used for adsorption of methylene blue (MB). Both compounds possessed high absorption capacities, the adsorption equilibrium time is around 10 min. HApS230 sample shows higher adsorption capacity compared to HApS220. Furthermore, isotherm studies show that the adsorption used is an ion exchange process and that Temkin isotherm describes the adsorption better compared to the Langmuir and Freundlich and Dubinin-Radushkevich isotherms. Kinetics studies confirm that the adsorption follow the pseudo-second order model and chemisorption mechanism. Thermodynamics’ studies confirm that the adsorption of MB on HApS samples is a spontaneous endothermic process. The average removal effectiveness of MB reached about 89.02% (6.389 mg/g adsorption capacity) and 91.36% (6.55 mg/g adsorption capacity) for HApS220 and HApS230 respectivel

Physicochemical study of magnesium zinc codoped-hydroxyapatite

Mg-Zn-doped hydroxyapatites in the system Ca9.4-xMg0.6Znx(PO4)6(OH)2 (x= 0, 0.1, 0.2, 0.4 and 0.6) were synthesized via sol-gel method. The obtained powder was calcined at 600°C and 700°C. X-ray diffraction (XRD) patterns and Infra-Red (IR) spectra confirmed the formation of pure hydroxyapatite up to 2% Zn content (a trace of β-pyrophosphate is detected for x=0), while a mixture of hydroxyapatite and β-TCP was formed for 4 mol%. With 6 mol%, only β-TCP formed. Moreover, at 700°C, all powders turned to be composed of solely β-TCP. The unit cell constants have also been calculated and match well with hexagonal (P63/m) hydroxyapatite

Hadron calorimeter with MAPD readout in the NA61/SHINE experiment

The modular hadron calorimeter with micro-pixel avalanche photodiodes readout for the NA61/SHINE experiment at the CERN SPS is presented. The calorimeter consists of 44 independent modules with lead-scintillator sandwich structure. The light from the scintillator tiles is captured by and transported with WLS-fibers embedded in scintillator grooves. The construction provides a longitudinal segmentation of the module in 10 sections with independent MAPD readout. MAPDs with pixel density of $~10^{4}$/mm$^2$ ensure good linearity of calorimeter response in a wide dynamical range. The performance of the calorimeter prototype in a beam test is reported

Advanced Technologies for Oral Controlled Release: Cyclodextrins for oral controlled release

Cyclodextrins (CDs) are used in oral pharmaceutical formulations, by means of inclusion complexes formation, with the following advantages for the drugs: (1) solubility, dissolution rate, stability and bioavailability enhancement; (2) to modify the drug release site and/or time profile; and (3) to reduce or prevent gastrointestinal side effects and unpleasant smell or taste, to prevent drug-drug or drug-additive interactions, or even to convert oil and liquid drugs into microcrystalline or amorphous powders. A more recent trend focuses on the use of CDs as nanocarriers, a strategy that aims to design versatile delivery systems that can encapsulate drugs with better physicochemical properties for oral delivery. Thus, the aim of this work was to review the applications of the CDs and their hydrophilic derivatives on the solubility enhancement of poorly water soluble drugs in order to increase their dissolution rate and get immediate release, as well as their ability to control (to prolong or to delay) the release of drugs from solid dosage forms, either as complexes with the hydrophilic (e.g. as osmotic pumps) and/ or hydrophobic CDs. New controlled delivery systems based on nanotechonology carriers (nanoparticles and conjugates) have also been reviewed

LA PSEUDOEXFOLIATION CAPSULAIRE ET LA CHIRURGIE DE LA CATARACTE (A propos de 74 cas)

But : Étudier les caractéristiques épidémiologiques et cliniques et les complications liées à la chirurgie de la cataracte dans la pseudoexfoliation capsulairePatients et méthodes : nous avons mené une étude rétrospective concernant 74 cas de syndrome de PEC sur les 760 patients programmés pour chirurgie de cataracte au service d’ophtalmologie de l’hôpital militaire sur une période de 3 ans.Résultats : nous avons constaté une prévalence de 9,74% qui augmente avec l’âge, le sexe n’est pas lié à la PEC, celle-ci est significativement associée au glaucome chronique à angle ouvert (p=0,01), à une mauvaise dilatation irienne (p=0,03), une acuité visuelle basse en pré et postopératoire (p<0,05) et à l’oedème cornéen postopératoire (p=0,04), par ailleurs les complications peropératoires sont les mêmes dans les deux groupes.Discussion : Notre étude montre que la PEC est une affection fréquente parmi les patients programmés pour chirurgie de cataracte avec une prévalence de 9,74%, affectant les sujets âgés, la majorité des études rapporte une association fortement significative avec le glaucome primitif à angle ouvert, et expose plus aux complications peropératoires, lors de la chirurgie de cataracte, liées à la mauvaise dilatation et postopératoires notamment les décompensations cornéales.Conclusion : Le syndrome de la PEC doit être toujours recherché chez les patients candidats à la chirurgie de la cataracte notamment s’ils sont âgés, enfin on insiste sur l’utilité d’un travail d’envergure multicentrique et randomisé et multifactoriel consacré à l’étude de la PEC

Comparative evaluation of polymeric and waxy microspheres for combined colon delivery of ascorbic acid and ketoprofen

International audienceThe goal of this work was to combine the ketoprofen anti-inflammatory effect with the ascorbic acid antioxidant properties for a more efficient treatment of colonic pathologies. With this aim, microspheres (MS) based on both waxy materials (ceresine, Precirol and Compritol (R)) or hydrophilic biopolymers (pectine, alginate and chitosan) loaded with the two drugs were developed, physicochemically characterized and compared in terms of entrapment efficiency, in vitro release profiles, potential toxicity and drug permeation properties across the Caco-2 cell line. Waxy MS revealed an high encapsulation efficiency of ketoprofen but a not detectable entrapment of ascorbic acid, while polymeric MS showed a good entrapment efficiency of both drugs. All MS need a gastro-resistant coating, to avoid any premature release of the drugs. Ketoprofen release rate from polymeric matrices was clearly higher than from the waxy ones. In contrast, the ASC release rate was higher, due to its high hydro-solubility. Cytotoxicity studies revealed the safety of all the formulations. Transport studies showed that the ketoprofen apparent permeability increased, when formulated with the different MS. In conclusion, only polymeric MS enabled an efficient double encapsulation of both the hydrophilic and lipophilic drugs, and, in addition, presented higher drug release rate and stronger enhancer properties. (C) 2015 Elsevier B.V. All rights reserved