Search results for " powder"

showing 10 items of 93 documents

Rapid and eco-friendly synthesis of graphene oxide-silica nanohybrids

2014

The increasing interest in Graphene oxide (GO) is due to many issues: the presence of both sp2-conjugated atoms and oxygen-containing functional groups provides a strong hydrophilicity and the possibility to further functionalize it with other molecules (i.e. π-π interactions covalent attachment etc.) [1]. Furthermore since the GO is biocompatible and noncytotoxic many studies have been recently focused on the development of GO-based nanodevices for bioimaging DNA detection drug delivery. Due to their low cytotoxicity and large internal surface area silica nanoparticles have been taken into account as promising material for biolabeling and drug loading/delivery. Particular consideration has recently been demonstrated for GO-silica composites because of the potentialities for electrical applications their chemical inertia and stability toward ions exposure. The possibility to combine the extraordinary properties of GO and silica offers several advantages for the realization of nanoprobes for biological applications and of biosensor [12]. The strategy for the fabrication of GO-nanosilica nanohybrids can be schematized as follows: (i) synthesis of GO by oxidizing graphite powder with the method described by Marcano et al. [3] (ii) Preparation of oxygen-loaded silica nanoparticles by thermal treatments in controlled atmosphere in order to induce high NIR emission at 1272 nm from high purity silica nanoparticles. (iii) preparation of GrO-silica nanohybrid films via rapid solvent casting in water. The nanohybrids were tested by XPS FTIR Raman analysis UV photoluminescence analysis TGA Zeta potential measurements electrical tests AFM and SEM. Several nanohybrids were prepared by combining two different typologies of GO and two different samples of silica.
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Structural Characterisation of Complex Layered Double Hydroxides and TGA-GC-MS Study on Thermal Response and Carbonate Contamination in Nitrate- and …

2015

Layered double hydroxides (LDHs) are versatile materials used for intercalating bioactive molecules in the fields of pharmaceuticals, nutraceuticals and cosmetics, with the purpose of protecting them from degradation, enhancing their water solubility to increase bioavailability and improving their pharmacokinetic properties and formulation stability. Moreover, LDHs are used in various technological applications to improve stability and processability. The crystal chemistry of hydrotalcite-like compounds was investigated by X-ray powder diffraction (XRPD), automated electron diffraction tomography (ADT) and thermogravimetric analysis (TGA)-GC-MS to shed light on the mechanisms involved in io…

Thermogravimetric analysishydrotalcytethermal responseInorganic chemistryIntercalation (chemistry)intercationsion exchangeengineering.materialCatalysischemistry.chemical_compoundCrystallinityAdsorptionlayered compoundsOrganic chemistryTGAHydrotalciteIon exchangeChemistryOrganic Chemistryelectron diffraction; intercations; ion exchange; layered compounds; structure elucidationstructure elucidationLayered double hydroxidesstructural characterization hydrotalcyte TGA GC-MS thermal response X-ray powderGeneral ChemistryX-ray powderstructural characterizationengineeringCarbonateelectron diffractionGC-MS
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Nano into Micro Formulations of Tobramycin for the Treatment of Pseudomonas aeruginosa Infections in Cystic Fibrosis.

2017

Here, nano into micro formulations (NiMs) of tobramycin for the treatment of Pseudomonas aeruginosa airway infections in cystic fibrosis (CF) are described. NiMs were produced by spray drying a solution containing polymers or sugars and a nanometric polyanion–tobramcyin complex (PTC), able to achieve a prolonged antibiotic release. NiMs properties were compared to TOBIPodhaler(Novartis), the only one commercially available dry powder inhalatory formulation based on porous microparticles. Produced NiMs showed adequate characteristics for pulmonary administration, as spherical shape, micrometric size, and high cytocompatibility toward human bronchial epithelial cells. Contrarily to TOBIPodhal…

Tobramycin Cystic Fibrosis Artificial Mucus (CF-AM) αβ-poly-(N-2-hydroxyethyl)-DL-aspartamide (PHEA) ion pair complex nano into micro strategy Pseudomonas aeruginosa infections biofilmPolymers and PlasticsCystic FibrosisPolymersChemistry PharmaceuticalBioengineeringBronchi02 engineering and technologymedicine.disease_causeCystic fibrosisMicrobiologyBiomaterials03 medical and health sciences0302 clinical medicineDrug Delivery SystemsNano-Materials ChemistrymedicineTobramycinHumansPseudomonas InfectionsParticle SizeRespiratory Tract InfectionsCells CulturedDrug CarriersPseudomonas aeruginosaChemistryBiofilmDry Powder InhalersEpithelial Cells021001 nanoscience & nanotechnologyAntimicrobialmedicine.diseaseMucusPolyelectrolytesAnti-Bacterial Agents030228 respiratory systemSettore CHIM/09 - Farmaceutico Tecnologico ApplicativoSpray dryingBiofilmsDelayed-Action PreparationsPseudomonas aeruginosaTobramycinNanoparticles0210 nano-technologymedicine.drugBiomacromolecules
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Valence states of copper in copper ferrite spinels CuxFe3−xO4 (0 < x ≤ 1) fine powders: Evidence of copper insertion

1997

Abstract The oxidation in cation deficient spinels of copper iron spinels Cu x Fe 3− x O 4 (0 x ≤ 1) synthesized by soft chemistry with a grain size x per mole of ferrite, three oxidation phenomena corresponding to Cu + at B-sites (130°C), Fe 2+ at B-sites (180°C) and Cu + at A-sites (240°C) have been found in close relation with the cation-oxygen distance of each oxidizable cation. For nonstoichiometric synthesized spinels Cu x Fe 3− x O 4+ δ with δ x , the presence of additional interstitial Cu + ions has been envisaged. The oxidation temperature of these interstitial ions (> 300°C) is higher than that for Cu + ions at Asites suggesting that interstitial copper ions also essentially resid…

Valence (chemistry)Fine powderChemistryInorganic chemistryFerrite (magnet)chemistry.chemical_elementPhysical and Theoretical ChemistryCondensed Matter PhysicsInstrumentationCopperGrain sizeSoft chemistryIonThermochimica Acta
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Ethyl Pyrogallarene and Pyrogallarene: Synthesis, Structural Analysis and Derivatization

2004

In the acid-catalyzed synthesis of ethyl pyrogall[4]arene, a novel hexamer, ethyl pyrogall[6] arene, is obtained as a readily isolable minor product. Pyrogall[6]arene can be isolated from the reaction mixture in three different ways yielding the hexamer in different forms and stabilities. Crystallization from DMSO and then recrystallization from acetone gives a stable crystalline solid, recrystallization directly from acetone yields an unstable white powder, while direct recrystallization from THF gives a stable white powder. Both pyrogall[4]arene and pyrogall[6]arene crystallize readily with DMSO filling the voids in the crystal lattice. Co-crystallization studies of the hexamer isolated b…

White powderGeneral ChemistryCrystal structureRandom hexamerlaw.inventionAcylationchemistry.chemical_compoundCrystallographychemistrylawX-ray crystallographyPolymer chemistryAcetoneCrystallizationDerivatizationSupramolecular Chemistry
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Investigation of phthalocyanine crystals exposed to NO2 ambient gas

2002

Crystals of free base phthalocyanine (H2pc) and its unsubstituted metal derivatives Mpc (where M=Ni, Cu, Zn, Pb, and pc=C32H16N8 2−=phthalocyanine ligand) were examined after being exposed to NO2 ambient gas. Scanning electron microscopy (SEM) supported by X-ray microprobe analysis (EDAX), UV–Vis and FTIR spectroscopy as well as X-ray powder diffractometry (XRD) were applied to study the crystals chemistry and surface morphology. The NO2 molecules were found to penetrate the crystal unit which led to the breakdown of the phthalocyanine macrocycle. The surface of the doped crystals has been scaled and covered by a layer composed predominantly of phthalimide. Despite vacuum desorption, it has…

X-ray powder diffractometryMicroprobeScanning electron microscopePhthalocyaninesAnalytical chemistryInorganic ChemistryMetalCrystalchemistry.chemical_compoundAdsorptionchemistryvisual_artDesorptionMaterials Chemistryvisual_art.visual_art_mediumPhthalocyanineUV–Vis and FTIR spectroscopyPhysical and Theoretical ChemistryFourier transform infrared spectroscopyScanning electron microscopyX-ray microprobeNitrogen dioxidePolyhedron
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Investigation of the SHS mechanisms of titanium nitride by in situ time-resolved diffraction and infrared thermography

2007

Abstract The self-propagating high-temperature synthesis (SHS) or combustion synthesis is a promising process to produce advanced ceramics due to the high purity of the elaborated materials and the very short synthesis time. Titanium nitride has been synthesised from pressed titanium powder and a nitrogen gas flow under a 0.1 MPa pressure. The influence of the addition of a TiN diluent was investigated. For the first time, SHS reaction mechanisms were determined from in situ time-resolved X-ray diffraction (TRXRD) experiments using the synchrotron radiation. These experiments were coupled with infrared thermography to study the propagation of the combustion reaction. It appeared that the in…

[ PHYS.COND.CM-MS ] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]Self-propagating high-temperature synthesischemistry.chemical_elementMineralogy02 engineering and technologyNitrideCombustion01 natural sciences7. Clean energyChemical reactionchemistry.chemical_compound0103 physical sciencesMaterials Chemistry010302 applied physicsMechanical EngineeringMetals and Alloys021001 nanoscience & nanotechnologyTitanium nitrideTitanium powderchemistryChemical engineeringMechanics of Materials[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]0210 nano-technologyTinTitaniumJournal of Alloys and Compounds
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Impact of lipid extraction on the dearomatisation of an Eisenia foetida protein powder

2010

www.elsevier.com/locate/foodchem ; FSTA:2010-Sp0197; International audience; Delipidation was studied as a way to dearomatise a non-conventional protein powder obtained from Eisenia foetida earthworms. In the first step, we studied the impact of several factors such as solvent type, extraction method and particle size on the yield of extracted lipids. Lipid extraction from samples was considerably improved using an ultrasound method with a chloroform/methanol mixture and small particle size. In the second step, the volatile compounds were extracted from the delipidated protein powder by the SAFE extraction method and by the HS-SPME method, and were further analysed by GC-MS. The chloroform/…

[ SDV.AEN ] Life Sciences [q-bio]/Food and Nutritionsafe extractionlipid extractiongc-mshs-spme01 natural sciencesAnalytical Chemistrychemistry.chemical_compound0404 agricultural biotechnologyLipid extractionvolatile compoundsprotein powderChloroformChromatography010401 analytical chemistryExtraction (chemistry)04 agricultural and veterinary sciencesGeneral Medicine040401 food science0104 chemical sciencesSolventchemistryYield (chemistry)MethanolParticle sizedearomatisationGas chromatography–mass spectrometry[SDV.AEN]Life Sciences [q-bio]/Food and NutritionFood Science
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The protein dynamical transition does not require the protein polypeptide chain

2011

We give experimental evidence that the main features of protein dynamics revealed by neutron scattering, i.e., the “protein dynamical transition” and the “boson peak”, do not need the protein polypeptide chain. We show that a rapid increase of hydrogen atoms fluctuations at about 220 K, analogous to the one observed in hydrated myoglobin powders, is also observed in a hydrated amino acids mixture with the chemical composition of myoglobin but lacking the polypeptide chain; in agreement with the protein behavior, the transition is abolished in the dry mixture. Further, an excess of low-frequency vibrational modes around 3 meV, typically observed in protein powders, is also observed in our mi…

chemistry.chemical_classificationHydrogenProtein dynamicsProtein mean square displacementchemistry.chemical_elementNeutron scatteringHydrated powdersInelastic neutron scatteringAmino acidAmino acidCrystallographychemistry.chemical_compoundchemistryMyoglobinMolecular vibrationSide chainProtein dynamicGeneral Materials ScienceElastic neutron scatteringPhysical and Theoretical ChemistryChemical composition
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New syntheses of condensed heterocycles from isoxazole derivatives. V. Pyrrolo[3,4-b]pyridin-4-ones

1977

Hydrogenolysis with Raney-Nickel or iron powder in acetic acid of 2,5-diphenyl-4-nitro-3-(3,5-R,R-4-isoxazolyl)pyrrolyl ketones, prepared by the Grignard reaction of 2,5-diphenylpyrrole and 3,5-R,R-4-isoxazolecarboxilic acid chlorides followed by nitration, afforded directly the desired 6H-pyrrolo[3,4-b ]pyridin-4-ones.

chemistry.chemical_compoundAcetic acidChemistryHydrogenolysisNitrationOrganic ChemistryGrignard reactionOrganic chemistryIsoxazoleIron powderJournal of Heterocyclic Chemistry
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