Search results for "Particle size"
showing 10 items of 631 documents
Caged Dexamethasone/Quercetin Nanoparticles, Formed of the Morphogenetic Active Inorganic Polyphosphate, are Strong Inducers of MUC5AC
2021
Inorganic polyphosphate (polyP) is a widely distributed polymer found from bacteria to animals, including marine species. This polymer exhibits morphogenetic as well as antiviral activity and releases metabolic energy after enzymatic hydrolysis also in human cells. In the pathogenesis of the coronavirus disease 2019 (COVID-19), the platelets are at the frontline of this syndrome. Platelets release a set of molecules, among them polyP. In addition, the production of airway mucus, the first line of body defense, is impaired in those patients. Therefore, in this study, amorphous nanoparticles of the magnesium salt of polyP (Mg-polyP-NP), matching the size of the coronavirus SARS-CoV-2, were pr…
Impact of cloud processes on aerosol particle properties: results from two ATR-42 flights in an extended stratocumulus cloud layer during the EUCAARI…
2011
Abstract. Within the European Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) project, the Meteo France research aircraft ATR-42 was operated from Rotterdam airport during May 2008, to perform scientific flights dedicated to the investigation of aerosol-cloud interactions. Therein, the objective of this study is to illustrate the impact of cloud processing on the aerosol particles physical and chemical properties. The presented results are retrieved from measurements during a double-flight mission from Rotterdam (Netherlands) to Newcastle (UK) and back using data measured with compact Time of Flight Aerosol Mass Spectrometer (cToF-AMS) and Scanning Mobility Particle Sizer (SMPS…
Microscopic Study of Injectable Steroids: Effects of Postmixing Time on Particle Aggregation
2020
Background: Epidural steroid injection (ESI) is a common practice for pain treatment since 1953. In 2014, the FDA issued a warning about ESI. Studies have focused on the effect of the particle size and their ability to generate harmful aggregates. Although steroid aggregates provide longer times for reabsorption, therefore a longer anti-inflammatory effect, they are potentially harmful to the central nervous system via embolic mechanisms. Previous studies have established that steroidal aggregates with asizes over 100 μm are potentially able to occlude blood vessels. Studies by Tiso et al and Benzon et al addressed the role of steroids on CNS adverse events, with similar outcomes. The main …
Ionic conduction, rectification, and selectivity in single conical nanopores
2006
Modern track-etching methods allow the preparation of membranes containing a single charged conical nanopore that shows high ionic permselectivity due to the electrical interactions of the surface pore charges with the mobile ions in the aqueous solution. The nanopore has potential applications in electrically assisted single-particle detection, analysis, and separation of biomolecules. We present a detailed theoretical and experimental account of the effects of pore radii and electrolyte concentration on the current-voltage and current-concentration curves. The physical model used is based on the Nernst-Planck and Poisson equations. Since the validity of continuum models for the descriptio…
Unexpected multivalent display of proteins by temperature triggered self-assembly of elastin-like polypeptide block copolymers
2012
We report herein the unexpected temperature triggered self-assembly of proteins fused to thermally responsive elastin-like polypeptides (ELPs) into spherical micelles. A set of six ELP block copolymers (ELP(BC)) differing in hydrophilic and hydrophobic block lengths were genetically fused to two single domain proteins, thioredoxin (Trx) and a fibronectin type III domain (Fn3) that binds the α(v)β(3) integrin. The self-assembly of these protein-ELP(BC) fusions as a function of temperature was investigated by UV spectroscopy, light scattering, and cryo-TEM. Self-assembly of the ELP(BC) was unexpectedly retained upon fusion to the two proteins, resulting in the formation of spherical micelles …
Computational and experimental studies of size and shape related physical properties of hydroxyapatite nanoparticles
2011
In this work, the properties of hydroxyapatite (HAP) nanoparticles (NPs) have been studied both theoretically and experimentally focusing on computational analysis. HAP is widely used to fabricate implants, for drug delivery, etc. The physical properties of the nanosized HAP particles play an important role in the interaction with cells in the human body and are of great interest. Computer simulation was employed to understand the properties of HAP clusters (Ca(5)(PO(4))(3)OH) including formation energies, dipole moments and polarization (surface charges) by molecular mechanics (MM + , OPLS) and mostly by quantum semi-empirical Hartree-Fock (PM3) methods. The size of the simulated cluster i…
Temperature-controlled release by changes in the secondary structure of peptides anchored onto mesoporous silica supports
2014
Changes in the conformation of a peptide anchored onto the external surface of mesoporous silica nanoparticles have been used to design novel temperature-controlled delivery systems.
Surface plasmons and vibrations of self-assembled silver nanocolumns
2006
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Mechanically interlocked calix[4]arene dimers display reversible bond breakage under force.
2009
The physics of nanoscopic systems is strongly governed by thermal fluctuations that produce significant deviations from the behaviour of large ensembles1,2. Stretching experiments of single molecules offer a unique way to study fundamental theories of statistical mechanics, as recently shown for the unzipping of RNA hairpins3. Here, we report a molecular design based on oligo calix[4]arene catenanes—calixarene dimers held together by 16 hydrogen bridges—in which loops within the molecules limit how far the calixarene nanocapsules can be separated. This mechanically locked structure tunes the energy landscape of dimers, thus permitting the reversible rupture and rejoining of the individual n…
Nondestructive Size Determination of Thiol-Stabilized Gold Nanoclusters in Solution by Diffusion Ordered NMR Spectroscopy
2013
Diffusion ordered NMR spectroscopy (DOSY) was used as an analytical tool to estimate the size of thiol-stabilized gold nanoclusters in solution, namely, phenylethanethiol (PET) stabilized Au25(PET)18, Au38(PET)24, and Au144(PET)60. This was achieved by determining the diffusion coefficient and hydrodynamic radius from solution samples that were confirmed to be monodispersed by electrospray ionization mass spectrometry. The average cluster diameters obtained by this technique were estimated to be 1.7, 2.2, and 3.1 nm for the Au25(PET)18, Au38(PET)24, and Au144(PET)60 nanoclusters, respectively, which were shown to agree well with the average diameters of the corresponding single crystal or t…