Search results for " atom"

showing 10 items of 1526 documents

Zinc accumulation in the telencephalon of lizards.

1987

The zinc concentration in the brains of two species of lizard was determined by atomic-absorption spectrophotometry. The zinc concentration was found to be highest in the telencephalon of Lacerta galloti (21.1 micrograms/g fresh weight) and Podarcis hispanica (16.77 +/- 0.8 micrograms/g) while the mesencephalon and brain stem exhibited lower zinc concentrations, i.e., 7.0 micrograms/g in Lacerta galloti and 6.08 +/- 0.4 micrograms/g in Podarcis hispanica. This high telencephalic concentration of zinc is paralleled by intense and well-defined Timm reactivity used for demonstrating the presence of zinc-containing boutons at the light-microscope level. Volumetric-densitometric studies of these…

TelencephalonHistologyCentral nervous systemchemistry.chemical_elementZincPodarcis hispanicaMidbrainMesencephalonbiology.animalmedicineLacertaAnimalsSauriaMolecular BiologybiologyCerebrumLizardSpectrophotometry AtomicLizardsCell BiologyGeneral MedicineAnatomybiology.organism_classificationMolecular biologyMedical Laboratory TechnologyZincmedicine.anatomical_structurechemistryAnatomyGeneral Agricultural and Biological SciencesBrain StemHistochemistry
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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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Analysis of archaeological samples and local clays using ICP-AES, TG–DTG and FTIR techniques

2000

Abstract The spectrochemical and thermal analysis of different archaeological samples as bricks, terra-cotta and local clays were carried out. The concentration of major and minor elements of samples was determined by sequential inductively coupled plasma atomic emission spectrometry. The method was tested by determining Si, Al, Fe, Ca, Mg, Mn, Pb, Cu, Zn, Ti, Na and K in the standard solutions and reference material GXR-4. The precision of the determination (relative standard deviation) ranged from 0.4 to 1.54%. The clay minerals are the main materials for the production of bricks and terra-cotta figures. Thermogravimetric (TG) and differential (TG–DTG) analysis and Fourier transform infra…

Thermogravimetric analysisEvolved gas analysisChemistryInductively coupled plasma atomic emission spectroscopyAnalytical chemistryFourier transform infrared spectroscopyStandard solutionInductively coupled plasmaClay mineralsThermal analysisArchaeologyAnalytical ChemistryTalanta
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Surface modification of luminescent lanthanide phosphate nanorods with cationic "Quat-primer" polymers.

2011

"Quat-primer" polymers bearing cationic groups were investigated as a surface modifier for Tb-doped cerium phosphate green-emitting fluorescent nanorods (NRs). The NRs were synthesized by a microwave process without using any complex agents or ligands and were characterized with different analytical tools such as X-ray diffraction, transmission electron microscopy, and fluorescence spectroscopy. Poly(ethyleneimine) partially quarternized with glycidyltrimethylammonium chloride was synthesized separately and characterized in detail. (1)H and (13)C NMR spectroscopic studies revealed that the quaternary ammonium group was covalently attached to the polymer. UV-vis spectroscopy was used to exam…

Thermogravimetric analysisMagnetic Resonance SpectroscopyPolymersInorganic chemistryMicroscopy Atomic Force530Fluorescence spectroscopyPhosphatesMicroscopy Electron TransmissionX-Ray DiffractionLanthanumElectrochemistryGeneral Materials ScienceSpectroscopySpectroscopychemistry.chemical_classificationNanotubesChemistryCationic polymerizationSurfaces and InterfacesPolymerCondensed Matter PhysicshumanitiesDispersion stabilitySurface modificationNanorodhuman activitiesLangmuir : the ACS journal of surfaces and colloids
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Nanocomposites of bacterial cellulose/hydroxyapatite for biomedical applications.

2008

In the present work, a nanocomposite material formed by bacterial cellulose (BC) networks and calcium-deficient hydroxyapatite (HAp) powders was synthesized and characterized. The HAp nanoparticles were previously prepared by a wet chemical precipitation method, starting from aqueous solutions of calcium nitrate and di-ammonium phosphate salts. Energy-dispersive spectroscopy reveals that the prepared HAp corresponds to calcium-deficient hydroxyapatite. BC-HAp nanocomposites were prepared by introducing carboxymethylcellulose (CMC) into the bacteria culture media. HAp nanoparticles were then introduced and remained suspended in the culture medium during the formation of cellulose nanofibrils…

Thermogravimetric analysisMaterials scienceBiocompatibilityBiomedical EngineeringAnalytical chemistryBiocompatible MaterialsMicroscopy Atomic ForceBiochemistryCell LineNanocompositesBiomaterialschemistry.chemical_compoundCrystallinityX-Ray DiffractionSpectroscopy Fourier Transform InfraredHumansCelluloseCelluloseMolecular BiologyNanocompositeBacteriaGeneral MedicineThermogravimetryDurapatitechemistryChemical engineeringBacterial celluloseAttenuated total reflectionCarboxymethylcellulose SodiumThermogravimetryPowdersBiotechnologyActa biomaterialia
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Synthesis, infrared and121Sb M�ssbauer spectra of some Antimony(III) Thiocyanate Complexes

1989

The first isolation of an antimony(III) thiocyanate complex salt, [(CH3)4N][Sb(CNS)4] (I), and of two adducts of the Sb(CNS)3 formal unit with potentially tridentate nitrogen donors, Sb(CNS)3tpta (II) and [Sb(CNS)3]3(dqp)2 (III), is described. In these derivatives, infrared and Mossbauer spectral data are essentially indicating the predominant presence of N-bonded thiocyanate. For complex I, the occurrence also of groups bridging through the nitrogen atom is advanced. Synthese, IR- und 121Sb-Mosbauer-Spektren von Antimon (III)-thiocyanat-Komplexen Die erstmalige Darstellung eines Antimon(III)-thiocyanat-Komplexes, [(CH3)4N][Sb(CNS)4] (I) und von zwei Addukten der formalen Sb(CNS)3-Einheit m…

ThiocyanateInfraredStereochemistrychemistry.chemical_elementMedicinal chemistryAdductInorganic Chemistrychemistry.chemical_compoundchemistryAntimonyNitrogen atomMössbauer spectroscopyMossbauer spectraSpectral dataZeitschrift f�r anorganische und allgemeine Chemie
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A new biodegradable and biocompatible hydrogel with polyaminoacid structure

2007

The preparation and physicochemical and biological characterization of a novel polyaminoacid hydrogel have been reported. The ,-poly(N-2- hydroxyethyl)-dl-aspartamide (PHEA) has been used as a starting polymer for a derivatization reaction with methacrylic anhydride (MA) to give rise to the methacrylate derivative named PHM. Photocrosslinking of PHM has been performed in aqueous solution at 313 nm and in the absence of toxic initiators. PHM-based hydrogel has been characterized by scanning electron microscopy, X-ray diffractometry, swelling measurements in aqueous media; the degradation of PHM-based hydrogel has been evaluated as a function of time in the absence or in the presence of ester…

Time FactorsBiocompatibilityCell SurvivalSurface PropertiesChemistry PharmaceuticalPharmaceutical ScienceMethacrylic anhydrideBiocompatible MaterialsMicroscopy Atomic ForceMethacrylateDosage formchemistry.chemical_compoundPolymethacrylic AcidsX-Ray DiffractionSpectroscopy Fourier Transform InfraredPolymer chemistryHumansTechnology PharmaceuticalDrug CarriersAqueous solutionHydrolysisEsterasestechnology industry and agricultureWaterHydrogelshydrogels FT-IRBlood ProteinschemistrySelf-healing hydrogelsDrug deliveryMicroscopy Electron ScanningK562 CellsPeptidesDrug carrierPorosityProtein BindingNuclear chemistryInternational Journal of Pharmaceutics
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Copper, iron, and zinc contents in human milk during the first three months of lactation: A longitudinal study

2000

The aim of the study has been to analyze the evolution of copper, iron, and zinc contents in human milk, from colostrum to the third postpartum month, following a longitudinal design, under specific conditions of sample collection and to apply an analytical procedure previously optimized to reduce any variation outside physiological lactation. The copper, iron, and zinc concentrations in 144 milk samples from 39 healthy puerpera women, were analyzed in five stages by flame atomic absorption spectrometry, following a standardized protocol. Copper presented a gradual decrease from 0.38 mg/L to 0.19 mg/L by the 90th day; the particular analysis from colostrum to transitional milk manifested th…

Time FactorsIronEndocrinology Diabetes and MetabolismClinical Biochemistrychemistry.chemical_elementZincBiochemistryInorganic ChemistryAnimal scienceFlame atomic absorption spectrometryLactationmedicineHumansLactationLongitudinal StudiesMilk HumanChemistryColostrumSpectrophotometry AtomicBiochemistry (medical)General MedicineCopperZincFirst trimestermedicine.anatomical_structureEnvironmental chemistryIron contentColostrumFemaleSample collectionCopper
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Partially Reversible Adsorption of Annexin A1 on POPC/POPS Bilayers Investigated by QCM Measurements, SFM, and DMC Simulations

2005

The kinetics of annexin A1 binding to solid-supported lipid bilayers consisting of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoserine (POPS; 4:1) has been investigated as a function of the calcium ion concentration in the bulk phase. Quartz crystal microbalance measurements in conjunction with scanning force microscopy, fluorescence microscopy, and computer simulations indicate that at a given Ca2+ concentration annexin A1 adsorbs irreversibly on membrane domains enriched in POPS. By contrast, annexin A1 adsorbs reversibly on the POPC-enriched phase, which is composed of single POPS molecules embedded within a POPC matrix. The overall are…

Time FactorsSurface PropertiesLipid BilayersKineticsAnalytical chemistryBiosensing TechniquesPhosphatidylserinesMicroscopy Atomic ForceBiochemistrychemistry.chemical_compoundAdsorptionPhase (matter)MicroscopyComputer SimulationParticle SizeLipid bilayerMolecular BiologyPOPCAnnexin A1ChemistryOrganic Chemistrytechnology industry and agricultureMembranes ArtificialQuartz crystal microbalanceMembraneMicroscopy FluorescencePhosphatidylcholinesMolecular Medicinelipids (amino acids peptides and proteins)AdsorptionStress MechanicalMonte Carlo MethodChemBioChem
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Rubidium dimers in paraffin-coated cells

2010

Measurements were made to determine the density of rubidium dimer vapor in paraffin-coated cells. The number density of dimers and atoms in similar paraffin-coated and uncoated cells was measured by optical spectroscopy. Due to the relatively low melting point of paraffin, a limited temperature range of 43-80 deg C was explored, with the lower end corresponding to a dimer density of less than 10^7 cm^(-3). With one-minute integration time, a sensitivity to dimer number density of better than 10^6 cm^(-3) was achieved. No significant difference in dimer density was observed between the cells.

Time delay and integrationPhysicsQuantum PhysicsNumber densityAtomic Physics (physics.atom-ph)DimerSignificant differenceAnalytical chemistryGeneral Physics and Astronomychemistry.chemical_elementLow melting pointFOS: Physical sciences02 engineering and technologyAtmospheric temperature range021001 nanoscience & nanotechnology01 natural sciencesPhysics - Atomic PhysicsRubidiumchemistry.chemical_compoundchemistry0103 physical sciences010306 general physics0210 nano-technologySpectroscopyQuantum Physics (quant-ph)
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