Search results for "Probe"

showing 10 items of 534 documents

Printing Life-Inspired Subcellular Scale Compartments with Autonomous Molecularly Crowded Confinement.

2019

A simple, rapid, and highly controlled platform to prepare life-inspired subcellular scale compartments by inkjet printing has been developed. These compartments consist of fL-scale aqueous droplets (few µm in diameter) incorporating biologically relevant molecular entities with programmed composition and concentration. These droplets are ink-jetted in nL mineral oil drop arrays allowing for lab-on-chip studies by fluorescence microscopy and fluorescence life time imaging. Once formed, fL-droplets are stable for several hours, thus giving the possibility of readily analyze molecular reactions and their kinetics and to verify molecular behavior and intermolecular interactions. Here, this pla…

Surface PropertiesDNA hairpinBiomedical EngineeringGeneral Biochemistry Genetics and Molecular BiologyFluorescenceBiomaterialsSettore CHIM/01molecular crowdingbiomolecular confinementlife-like compartmentFluorescence microscopeInkjet printinginkjet printingBiochemistry Genetics and Molecular Biology (all)ChemistryDrop (liquid)Intermolecular forceLife timeDNABiomaterialFluorescencebiomolecular confinement; DNA hairpins; inkjet printing; life-like compartments; molecular crowdingDNA hairpinslife-like compartmentsPrinting Three-DimensionalBiophysicsMolecular probeAdvanced biosystems
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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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Sulfur isotope ratio measurements of individual sulfate particles by NanoSIMS

2008

Abstract The sulfur isotopic compositions of barite (BaSO4), anhydrite (CaSO4), gypsum (CaSO4·2H2O), mascagnite ((NH4)2SO4), thenardite (Na2SO4), boetite (K2SO4), epsomite (MgSO4·7H2O), magnesium sulfate (MgSO4·xH2O) and cysteine (an amino acid) were determined with a Cameca NanoSIMS 50 ion microprobe employing a Cs+ primary ion beam and measuring negative secondary ions. This ion microprobe permits the analysis of sulfur isotope ratios in sulfates on 0.001–0.5 ng of sample material, enabling the analysis of individual S-bearing particles with diameters as small as 500 nm. The grain-to-grain reproducibility of measurements is typically 5‰ (1σ) for micron-sized grains,

ThenarditeMicroprobeAnhydriteIon beamMagnesiumEpsomiteAnalytical chemistrychemistry.chemical_elementCondensed Matter PhysicsSulfurchemistry.chemical_compoundchemistryPhysical and Theoretical ChemistrySulfateInstrumentationSpectroscopyInternational Journal of Mass Spectrometry
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ChemInform Abstract: Relaxation Phenomena of a Triplet Spin Probe in Glassy and Crystalline o-Terphenyl.

2010

The authors used quinoxaline in its photoexcited triplet state as a spin probe in order to measure the spin-lattice relaxation rate in o-terphenyl glass as a function of temperature. They found a power law with an exponent close to 2. Since o-terphenyl can easily be crystallized, they investigated the crystal, too. Below 3.5 K the spin is highly polarized, contrary to the behavior in the glass, where it reaches thermal equilibrium down to the lowest temperatures of their experiment (1.4 K). Around 3.5 K the polarization in the crystal vanishes. Above it appears with opposite sign due to thermal equilibration.

Thermal equilibriumCondensed matter physicsGeneral MedicinePolarization (waves)Condensed Matter::Disordered Systems and Neural NetworksSpin probeCrystalchemistry.chemical_compoundchemistryTerphenylOrganic chemistryTriplet stateLuminescenceSpin (physics)ChemInform
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A G468-T AMPD1 mutant allele contributes to the high incidence of myoadenylate deaminase deficiency in the Caucasian population.

2002

Myoadenylate deaminase deficiency is the most common metabolic disorder of skeletal muscle in the Caucasian population, affecting approximately 2% of all individuals. Although most deficient subjects are asymptomatic, some suffer from exercise-induced myalgia suggesting a causal relationship between a lack of enzyme activity and muscle function. In addition, carriers of this derangement in purine nucleotide catabolism may have an adaptive advantage related to clinical outcome in heart disease. The molecular basis of myoadenylate deaminase deficiency in Caucasians has been attributed to a single mutant allele characterized by double C to T transitions at nucleotides +34 and +143 in mRNA enco…

ThreonineDNA ComplementaryGenotypeBlotting WesternGlycineMetabolic myopathyBiologyCompound heterozygosityPolymerase Chain ReactionWhite PeopleAMP DeaminaseMetabolic DiseasesMuscular DiseasesGenotypemedicineHumansAlleleTransversionMuscle SkeletalGenetics (clinical)AllelesElectromyographyPoint mutationMetabolic disorderAMP deaminasemedicine.diseaseMolecular biologyPhenotypeNeurologyPediatrics Perinatology and Child HealthMutationNeurology (clinical)DNA ProbesNeuromuscular disorders : NMD
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Simulating pump-probe photo-electron and absorption spectroscopy on the attosecond time-scale with time-dependent density-functional theory

2013

Molecular absorption and photoelectron spectra can be efficiently predicted with real-time time-dependent density functional theory. We show herein how these techniques can be easily extended to study time-resolved pump-probe experiments, in which a system response (absorption or electron emission) to a probe pulse is measured in an excited state. This simulation tool helps with the interpretation of fast-evolving attosecond time-resolved spectroscopic experiments, in which electronic motion must be followed at its natural timescale. We show how the extra degrees of freedom (pump-pulse duration, intensity, frequency, and time delay), which are absent in a conventional steady-state experimen…

Time-resolved spectroscopyTime FactorsAbsorption spectroscopyAtomic Physics (physics.atom-ph)AttosecondAttosecond dynamicsFOS: Physical sciencesPump probesingle-molecule studies01 natural sciencestime-resolved spectroscopySettore FIS/03 - Fisica Della MateriaPhysics - Atomic PhysicsAb initio quantum chemistry methodsPhysics - Chemical Physics0103 physical sciencesPhysics - Atomic and Molecular ClustersLaser spectroscopyPhysical and Theoretical Chemistry010306 general physicsSpectroscopyPhysicsChemical Physics (physics.chem-ph)010304 chemical physicsEuropean researchab initio calculationsPhotoelectron SpectroscopySingle-molecule studiesattosecond dynamicsTime-dependent density functional theoryAtomic and Molecular Physics and OpticsPhysics - Plasma PhysicsPlasma Physics (physics.plasm-ph)X-Ray Absorption Spectroscopylaser spectroscopyQuantum TheoryAtomic physicsTime-resolved spectroscopyAtomic and Molecular Clusters (physics.atm-clus)
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Photon Scanning Tunneling Microscopy and Reflection Scanning Microscopy

1991

The Photon Scanning Tunneling Microscope (PSTM) is the photon analogue to the Electron Scanning Tunneling Microscope (ESTM). It uses the evanescent field due to the total internal reflection (TIR) of a light beam in a prism modulated by a sample attached to the prism. The exponential decay of the evanescent field is characterized by the penetration depth dp and depends on the angle of incidence θ, the wavelength and polarization of the incident beam. Changes in intensity are monitored by a probe tip scanned over the surface, and the data are processed to generate an image of the sample. Images produced by a prototype instrument are shown to have a vertical resolution of about 3 A and a late…

Total internal reflectionMaterials sciencebusiness.industryScanning confocal electron microscopyPhysics::OpticsScanning capacitance microscopylaw.inventionScanning probe microscopyOpticslawMicroscopyPrismScanning tunneling microscopebusinessVibrational analysis with scanning probe microscopy
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Resolution of the photon scanning tunneling microscope: influence of physical parameters

1992

Abstract The photon scanning tunneling microscope (PSTM) is the photon analogue of the electron scanning tunneling microscope (ESTM). It uses the evanescent field due to total internal reflection (TIR) of a light beam in a prism modulated by a sample placed on the base of the prism. Our experimental results shown details which present a lateral size as small as 200 A. The PSTM axial resolution is more difficult to evaluate. It is a function of the roughness of the sample. For very smooth samples, images shown an axial resolution of about 10 A. At last we discuss how both lateral and axial resolution can be affected by several parameters such as the tip surface distance and the roughness of …

Total internal reflectionScanning Hall probe microscopeChemistrybusiness.industryResolution (electron density)Scanning tunneling spectroscopySpin polarized scanning tunneling microscopyAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic Materialslaw.inventionScanning probe microscopyOpticslawPrismScanning tunneling microscopebusinessInstrumentationUltramicroscopy
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The sex determining region of Chironomus thummi is associated with highly repetitive DNA and transposable elements.

1993

The dominant male sex determiner in chromosome III of the midge Chironomus thummi thummi is closely linked to a large cluster of tandem-repetitive DNA elements, the Cla elements, which are otherwise highly repetitive and distributed over more than 200 sites on all chromosomes. Chromosome III displays a hemizygous cluster of Cla elements in males but not in females. The chromosomal location of this hemizygous Cla element cluster is in the region of the male determiner M as localized by cytogenetic analysis. With Cla elements as hybridization probe, it was possible to clone a large part of the sex determining region. Molecular analysis of the DNA of males and females in this region displayed …

Transposable elementMaleSex Determination AnalysisMolecular Sequence DataMolecular cloningBiologyChironomidaechemistry.chemical_compoundGeneticsAnimalsCloning MolecularRepeated sequenceGenetics (clinical)Repetitive Sequences Nucleic AcidGeneticsBase SequenceHybridization probeChromosomeChromosome MappingDNABiological EvolutionChromosome 3chemistryDNA Transposable ElementsFemaleRecombinationDNAChromosoma
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Examination of Escherichia coli from poultry for selected adhesin genes important in disease caused by mammalian pathogenic E. coli

2001

A collection of 1601 extraintestinal and intestinal Escherichia coli isolated from chickens, turkeys and ducks, in Belgium, France and Spain, was hybridised with gene probes specific for fimbrial and afimbrial adhesins (F17, F18, SSfa/F1C, Bfp, Afa, Cs31A, IntiminEae, Aida-1) of intestinal, urinary and invasive E. coli of mammals and with a probe specific for the P (Pap/Prs) fimbrial adhesin of urinary and invasive E. coli of mammals and birds. Three hundred and eighty-three strains (23.9%) were P-positive, 76 strains (4.8%) were Afa-positive, 75 strains (4.7%) were F17-positive, 67 strains (4.2%) were S-positive, 23 (1.4%) were Intimin-positive, and all were F18-, Cs31A-, Aida1- and Bfp-ne…

TurkeysGenotype[SDV]Life Sciences [q-bio]Protein subunitSONDE NUCLEIQUEmedicine.disease_causePolymerase Chain ReactionMicrobiologyMicrobiology03 medical and health sciencesBelgiumTECHNIQUE PCREscherichia colimedicineAnimalsAdhesins BacterialEscherichia coliGeneComputingMilieux_MISCELLANEOUSEscherichia coli InfectionsPoultry Diseases030304 developmental biologyIntimin0303 health sciencesGeneral Veterinarybiology030306 microbiologyGenetic variantsGeneral Medicinebiology.organism_classificationVirologyEnterobacteriaceae[SDV] Life Sciences [q-bio]Bacterial adhesinDucksSpainFimbriae BacterialFranceDNA ProbesChickensBacteriaVeterinary Microbiology
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