35 research outputs found
A kinetic study of the basic hydrolysis of 2-phenylethyl nitrite in the presence of borate buffer and ÎČ-cyclodextrin
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Modified montmorillonite as drug delivery agent for enhancing antibiotic therapy
The appealing properties of surfactantâintercalated Montmorillonites (Organo-montmorillonite, OMt) were successfully investigated to propose an effective drug delivery system for metronidazole (MNE) antibiotic therapy. This represents a serious pharmaceutical concern due to the adverse drug reactions and the low targeting ability of MNE. The nonâionic surfactant Tween 20 was used to functionalize montmorillonite, thus accomplishing the twoâfold objective of enhancing the stability of clay dispersion and better controlling drug uptake and release. The adsorption process was performed under different experimental conditions and investigated by constructing the adsorption isotherms through highâperformance liquid chromatography (HPLC) measurements. Powder Xâray diffraction (XRD) measurements were performed to characterize the MNE/OMt compounds. The gathered results revealed that the uptake of the drug occurs preferentially in the clay interlayer, and it is governed by positive cooperative processes. The presence of surfactant drives the adsorption into clay interlayer and hampers the adsorption onto external lamella faces. The good performances of the prepared OMt in the controlled release of the MNE were proved by investigating the release profiles under physiological conditions, simulating oral drug administration. Cytotoxicity measurements demonstrated the biocompatibility of the complexes and evidenced that, under specific experimental conditions, nanodevices are more biocompatible than a free drug
Challenges of information security incident learning: An industrial case study in a Chinese healthcare organization
Cross-Diffusion in a Water-in-Oil Microemulsion Loaded with Malonic Acid or Ferroin. Taylor Dispersion Method for Four-Component Systems
Control of spontaneous spirals formation in zwitterionic micellar medium
The transition from planar fronts, trigger waves or solitary pulses to spirals in excitable media, has attracted increasing interest in the past few decades, mainly because of its relevance for biological and medical applications. In this paper we describe a new and convenient method for spiral generation starting from symmetric wavefronts. By using the micelle-forming zwitterionic surfactant N-tetradecyl-N,N-dimethylamine oxide in a BelousovâZhabotinsky solution, it is possible to control to a large extent the domains where spirals can be spontaneously generated. The mechanism responsible for the wavefront break up lies in the interaction of the propagating waves with the unexcitable regions formed by the interaction of the surfactant with some of the BelousovâZhabotinsky key intermediates
Microstructure and magnetic properties of colloidal cobalt nano-clusters
The magnetic response of nanometer sized Co nanoparticles (NP) prepared using reverse micelle
solutions are presented. The use of complementary structural and morphological probes (like
transmission electron microscopy, high resolution electron microscopy, X-ray absorption spectroscopy)
allowed to relate the magnetic properties to the size, morphology, composition and atomic structure of
the nanoparticles. All data agree on the presence of a core\u2013shell structure of NPs made of a metallic Co
core surrounded by a thin Co-oxide layer. The core\u2013shell microstructure of NPs affects its magnetic
response mainly raising the anisotropy constant
Magnetic properties of colloidal cobalt nanoclusters
Co nanoclusters were synthesized by an inverse-micelle chemical route. The magnetic and microstructural properties of the nanoparticles have been analyzed as a function of the surfactant (AOT and DEHP) and the drying method. Microstructural analysis has been performed by TEM and XANES; magnetic properties have been studied by hysteresis loops and zero-field cooling â field cooling (ZFC-FC) curves. TEM images show 2 to 4 nm sized particles spherical in shape. XANES measurements point out a significant presence of Co3O4with metallic Co and some Co2+ bound to the surfactant. The presence of antiferromagnetic Co3O4 explains the magnetic transition observed at low T in both ZFC-FC measurements and hysteresis loops. Finally, the presence of magnetic interactions explains the bigger effective cluster size obtained from hysteresis loops fits (6-10 nm) compared to the sizes observed by TEM (2-4 nm)