Search results for "reparation"

showing 10 items of 944 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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Influence of sample pan on the thermal behaviour of KSCN measured with TG

2003

Abstract In this study, the influence of the sample pan on the thermal behaviour of potassium thiocyanate (KSCN) was investigated. The measurements were performed with thermogravimetry (TG) and the two sample pans used were a platinum pan and a ceramic crucible. The samples were heated to 400–950 °C and the thermal products were identified by powder diffraction. The thermal behaviour of KSCN was found to be dependent on the sample pan used. With the platinum sample pan KSCN reacted in the first step into a mixture of K 2 SO 4 and potassium tetracyanoplatinate (K 2 Pt(CN) 4 ). In the second step, the mixture reacted further to pure K 2 SO 4 . In the ceramic sample crucible, however, the reac…

ThiocyanateAnalytical chemistrychemistry.chemical_elementCondensed Matter PhysicsAlkali metalRubidiumThermogravimetrychemistry.chemical_compoundchemistryPotassium thiocyanateSample preparationPhysical and Theoretical ChemistryPlatinumThermal analysisInstrumentationThermochimica Acta
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PHEA-graft-polybutylmethacrylate copolymer microparticles for delivery of hydrophobic drugs.

2012

Abstract Polymeric microparticles encapsulating two model hydrophobic drugs, beclomethasone dipropionate (BDP) and flutamide (FLU) were prepared by using the high pressure homogenization-solvent evaporation method starting from a oil-in-water emulsion. For the preparation of polymeric microparticles a α,β-poly(N-2-hydroxyethyl)- d , l -aspartamide (PHEA) graft copolymer with comb like structure was properly synthesized via grafting from atom transfer radical polymerization (ATRP) technique, by using two subsequent synthetic steps. In the first step a polymeric multifunctional macroinitiator was obtained by the conjugation of a proper number of 2-bromoisobutyryl bromide (BIB) residues to the…

Time FactorsBioadhesivePharmaceutical ScienceCell LineDrug Delivery SystemsPolymethacrylic AcidsPolymer chemistryMucoadhesionCopolymerSide chainHumansPhea polybutylmethacrylate microparticles drug deliveryParticle SizeGlucocorticoidsDrug CarriersDose-Response Relationship DrugChemistryAtom-transfer radical-polymerizationBeclomethasoneAdhesivenessAndrogen AntagonistsGraftingFlutamideMicrospheresPolymerizationDelayed-Action PreparationsEmulsionSolventsNanoparticlesEmulsionsCaco-2 CellsPeptidesHydrophobic and Hydrophilic InteractionsInternational journal of pharmaceutics
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SYNTHESIS, CHARACTERIZATION AND IN VITRO CYTOTOXICITY STUDIES OF A MACROMOLECULAR CONJUGATE OF PACLITAXEL BEARING OXYTOCIN AS TARGETING MOIETY.

2007

The present study describes the experimental synthetic procedure and the characterization of a new polyaspartamide macromolecular prodrug of paclitaxel, bearing oxytocin residues as targeting moieties. In vitro stability studies of bioconjugate, performed in media mimicking biological fluids (buffer solutions at pH 7.4 and 5.5) and in human plasma, evidenced the high stability of the targeting portion (oxytocin)-polymer linkage and the ability of this conjugate to release linked paclitaxel in a prolonged way in plasma. Moreover, preliminary in vitro antiproliferative studies, carried out on MCF-7 cells, that are oxytocin receptor positive cells, showed that the polymeric conjugate has the s…

Time FactorsChemistry PharmaceuticalDrug CompoundingpolyaspartamidePharmaceutical ScienceBreast NeoplasmsPolyethylene Glycolschemistry.chemical_compoundpaclitaxelDrug StabilityCell Line TumoroxytocinHumansMoietyProdrugsbioconjugateCytotoxicityCell ProliferationDrug CarriersDose-Response Relationship DrugMolecular StructureHydrolysisdrug targetingGeneral MedicineHydrogen-Ion ConcentrationAntineoplastic Agents PhytogenicOxytocin receptorIn vitroSolubilityPaclitaxelchemistryBiochemistryTargeted drug deliveryReceptors OxytocinDelayed-Action PreparationsFemalePeptidesDrug carrierBiotechnologyConjugate
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Optimization of a matrix solid-phase dispersion method for the analysis of pesticide residues in vegetables

1996

A multiresidue method based on matrix solid-phase dispersion (MSPD) is studied to determine chlorfenvinfos, chlorpyrifos, fenarimol, iprodione, procimydone, propiconazole, tetradifon, triadimefon and vinclozolin in artichokes, green beans, lettuces and tomatoes. Alumina, silica and Florisil were assessed as extracting phases, and the extracts from Florisil were the cleanest. To facilitate manual extraction, sand was added to the sample together with the dispersing phase. Three eluting systems were then studied, and dichloromethane proved to be the best. Further purification can be performed using solid-phase cleanup after diluting extracts with aqueous solutions. Octyl- and octadecyl-silica…

Time FactorsChromatographyChemistryOrganic ChemistryPesticide ResiduesReproducibility of ResultsGeneral MedicineBiochemistryGas Chromatography-Mass SpectrometryAnalytical ChemistryMatrix (chemical analysis)chemistry.chemical_compoundElectron capture detectorVegetablesSelected ion monitoringSample preparationGas chromatographyProcymidoneSolid phase extractionVinclozolinJournal of Chromatography A
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Determination of the cultivar and aging of Sicilian olive oils using HPLC-MS and linear discriminant analysis

2010

A large number of certified samples (84) of Sicilian olive oils arising from the eight cultivars most represented in Sicily (Biancolilla, Cerasuola, Moresca, Nocellara del Belice, Nocellara Etnea, Oglialora Messinese, Brandofino and Tonda Iblea) have been collected and analyzed by HPLC/MS using an atmospheric pressure chemical ionization (APCI) source. The sample preparation is very simple; in fact, the oil samples are diluted without any chemical derivatization. A following statistical data treatment by general discriminant analysis (GDA) allows the determination of the olive oil cultivar. Furthermore, changes in the composition of glyceridic components of the olive oils lead to easy discr…

Time FactorsSettore CHIM/10 - Chimica Degli AlimentiLDAAtmospheric-pressure chemical ionizationMass SpectrometryGlyceridesChemometricschemistry.chemical_compoundLiquid chromatography–mass spectrometryPlant OilsSettore CHIM/01 - Chimica AnaliticaSample preparationCultivarDerivatizationOlive OilSicilyChromatography High Pressure LiquidSpectroscopyChemical ionizationChromatographyagingDiscriminant AnalysisHPLC/MSVegetable oilchemistryolive oil; HPLC/MS; LDA; cultivar; agingFood AnalysiscultivarJournal of Mass Spectrometry
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Prostaglandin E(2)-loaded microspheres as strategy to inhibit phagocytosis and modulate inflammatory mediators release.

2008

PGE(2), an arachidonic acid metabolite produced by various type of cells regulates a broad range of physiological activities in the endocrine, cardiovascular, gastrointestinal, and immune systems, and is involved in maintaining the local homeostasis. In the immune system, PGE(2) is mainly produced by APCs and it can suppress the Th1-mediated immune responses. The aim of this study was to develop PGE(2)-loaded biodegradable MS that prolong and sustain the in vivo release of this mediator. An o/w emulsion solvent extraction-evaporation method was chosen to prepare the MS. We determined their diameters, evaluated the in vitro release of PGE(2), using enzyme immunoassay and MS uptake by periton…

Time Factorsmedicine.medical_treatmentPhagocytosisChemistry PharmaceuticalDrug CompoundingPharmaceutical ScienceInflammationPharmacologyBiologyNitric OxideDinoprostonechemistry.chemical_compoundMiceImmune systemPhagocytosisIn vivoSepsismedicineAnimalsHumansImmunologic FactorsProstaglandin E2Particle SizeCells CulturedChemokine CCL2Tumor Necrosis Factor-alphaEndothelial CellsWaterGeneral MedicineMicrospheresDisease Models AnimalchemistryBiochemistrySolubilityDelayed-Action PreparationsMacrophages PeritonealLiberationlipids (amino acids peptides and proteins)Arachidonic acidEmulsionsmedicine.symptomInflammation MediatorsOilsBiotechnologyProstaglandin Emedicine.drugEuropean journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V
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Time-Gated Raman Spectroscopy for Quantitative Determination of Solid-State Forms of Fluorescent Pharmaceuticals

2018

Raman spectroscopy is widely used for quantitative pharmaceutical analysis, but a common obstacle to its use is sample fluorescence masking the Raman signal. Time-gating provides an instrument-based method for rejecting fluorescence through temporal resolution of the spectral signal and allows Raman spectra of fluorescent materials to be obtained. An additional practical advantage is that analysis is possible in ambient lighting. This study assesses the efficacy of time-gated Raman spectroscopy for the quantitative measurement of fluorescent pharmaceuticals. Time-gated Raman spectroscopy with a 128 X (2) X 4 CMOS SPAD detector was applied for quantitative analysis of ternary mixtures of sol…

Time Factorsspektroskopia116 Chemical sciencesAnalytical chemistry02 engineering and technologySpectrum Analysis Raman01 natural sciencesSignalAnalytical Chemistrysymbols.namesakeTime domainLeast-Squares Analysista116DETECTORFluorescent DyesSUPPRESSIONta113ta114Chemistry010401 analytical chemistryDetectorMIXTURESSENSORPIROXICAMRESONANCE021001 nanoscience & nanotechnologyRAY-POWDER DIFFRACTIONFluorescence0104 chemical sciencesSPADPharmaceutical PreparationsPHOTON AVALANCHE-DIODETemporal resolutionRaman spectroscopysymbolsCRYSTALLIZATION0210 nano-technologyRaman spectroscopyTernary operationQuantitative analysis (chemistry)
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[The effect of instrumentation on original apical foramen shape using steel vs niti rotatory: computerized analysis]

2002

BACKGROUND. A fundamental requirement to obtain a correct endodontic preparation depends on the respect, during cleaning and shaping, of the original morphology of the apical foramen, (AF), so that the filling material will form a complete seal. METHODS. In our previous studies, in order to verify if this presumption was respected using rotary NiTi instruments with cutting tip, we instrumented extracted teeth characterised by a different degree of root curvatures. Using a standardized system to replace the sample, the original shape of the apical foramen of each tooth was recorded using a computerised technique and then compared to the shape after instrumentation. The data showed difference…

TitaniumTooth ApexSettore MED/28 - Malattie OdontostomatologicheNickelImage Interpretation Computer-AssistedHumansStainless Steelrotary NiTi instruments stainless steel instruments apical foramen shapeRoot Canal PreparationDental Alloys
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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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