Search results for "Microsphere"

Whispering Gallery Mode Resonator Temperature Compensation and Refractive Index Sensing in Glucose Droplets.

2021

Among the different types of photonic sensor devices, optical whispering gallery mode resonators (WGMRs) have attracted interest due to their high level of sensitivity, small size, and ability to perform real-time temperature measurements. Here we demonstrate the applicability of temperature measurements using WGMR in both air and liquid environments. We also show that WGMR allowed measurements of the refractive index variations in an evaporating glucose–water solution droplet. The thermal tuning of WGMR can be reduced by coating WGMRs with a thin layer of polymethyl methacrylate (PMMA). Dip-coating the silica microsphere multiple times significantly reduced the resonance shift, partially c…

Functional Magnetic Mesoporous Silica Microparticles Capped with an Azo-Derivative: A Promising Colon Drug Delivery Device

2018

[EN] Magnetic micro-sized mesoporous silica particles were used for the preparation of a gated material able to release an entrapped cargo in the presence of an azo-reducing agent and, to some extent, at acidic pH. The magnetic mesoporous microparticles were loaded with safranin O and the external surface was functionalized with an azo derivative 1 (bearing a carbamate linkage) yielding solid S1. Aqueous suspensions of S1 at pH 7.4 showed negligible safranin O release due to the presence of the bulky azo derivative attached onto the external surface of the inorganic scaffold. However, in the presence of sodium dithionite (azoreductive agent), a remarkable safranin O delivery was observed. A…

Preparation of white beeswax microspheres loaded with valproic acid and kinetic study of drug release

1995

AbstractThe well known antiepileptic valproic acid (1) due to the long treatment of epilepsy may induce many adverse side effects on various systems. To minimize unwanted toxic effects by kinetic control of drug release, 1 was physically entrapped into white beeswax microspheres using the meltable dispersion process utilizing wetting agents. Solid, discrete, reproducible free flowing microspheres were obtained converting the liquid drug droplets into solid material. The average drug content was 17% w/w. More than 95% of the isolated microspheres were of particle size range 200-425 µm. The microspheres were analyzed to quantify the amount of incorporated drug and to characterize the in vitro…

Carnauba wax microspheres loaded with valproic acid: Preparation and evaluation of drug release

1995

AbstractTo minimize unwanted toxic effects of valproic acid (1) by the kinetic control of drug release, gastroresistant carnauba wax microspheres loaded with the antiepileptic agent were prepared. The preparation was based on a technique involving melting and dispersion of drug-containing wax in an aqueous medium. The resulting emulsion after cooling under rapid stirring produced solid, discrete, reproducible free flowing microspheres which converted the liquid drug droplets into solid material. About 94% of the isolated microspheres were of particle size range 200-425 μm. The microspheres were analyzed to determine the drug content in various particle size range and to characterize the in …

Micropartículas de PLLA y CHT como andamiaje para la regeneración del cartílago articular: Modelo animal.

2020

espanolLa naturaleza avascular del cartilago ha supuesto que historicamente las lesiones osteocondrales hayan tenido mal pronostico. Una de las opciones de tratamiento para dichas lesiones es el uso de andamiajes, siendo superior respecto a otras tecnicas que consiguen un fibrocartilago como resultado. Hemos elaborado microesferas de PLLA y CHT para usarlos como andamiaje en lesiones osteocondrales producidas a conejos albinos New Zealand. Se distribuyeron grupos con diferentes proporciones de microesferas, asi como un grupo control con la lesion sin tratar. Se analizo tambien el cartilago nativo de la rodilla contralateral. Se evaluaron las muestras para establecer la calidad del cartilago…

Dielectric Microspheres: Quantum Dots Luminescence Collection Enhancement and Nanoscopy by Dielectric Microspheres (Part. Part. Syst. Charact. 1/2020)

2020

Cytométrie en flux, microbilles et analyses biomoléculaires multiplexes

2005

Resume En cytometrie en flux, les microbilles constituent des outils importants. Initialement developpees pour optimiser les signaux de diffraction et de fluorescence detectes par les cytometres, les microbilles sont maintenant largement utilisees pour la quantification d'antigenes. Actuellement, leur utilisation comme support reactionnel permet aussi de detecter et de quantifier simultanement par cytometrie en flux plusieurs analytes tels que des proteines, des nucleotides, et des ions, mais aussi des agents infectieux dans quelques microlitres d'echantillon. Pour cela, des microbilles de fluorescences et/ou de tailles differentes couplees a des proteines ou a des oligonucleotides sont le …

Optical Frequency Combs Generated in Silica Microspheres in the Telecommunication C-, U-, and E-Bands

2021

Optical frequency combs (OFCs) generated in microresonators with whispering gallery modes are demanded for different applications including telecommunications. Extending operating spectral ranges is an important problem for wavelength-division multiplexing systems based on microresonators. We demonstrate experimentally three spectrally separated OFCs in the C-, U-, and E-bands in silica microspheres which, in principle, can be used for telecommunication applications. For qualitative explanation of the OFC generation in the sidebands, we calculated gain coefficients and gain bandwidths for degenerate four-wave mixing (FWM) processes. We also attained a regime when the pump frequency was in t…

Autoradiographic technique to assess distribution of blood flow within organs

1969

A method is described for assessing the distribution of blood flow within organs. Microspheres, 5–50 μ in diameter, labelled with a beta-emitting isotope were injected into the left ventricle of experimental animals. The distribution of the indicator within the tissues, which is assumed to represent the regional distribution of flow, was visualized and measured quantitatively by autoradiography. Local flow rates in areas of about 1,2 mm in diameter could be determined. Application of the technique for the study of regional myocardial and renal circulation is demonstrated.

Attachment of Marine Sponge Cells of Hymeniacidon perleve on Microcarriers

2003

Toward the development of an in vitro cultivation of marine sponge cells for sustainable production of bioactive metabolites, the attachment characteristics of marine sponge cells of Hymeniacidon perleve on three types of microcarriers, Hillex, Cytodex 3, and glass beads, were studied. Mixed cell population and enriched cell fractions of specific cell types by Ficoll gradient centrifugation (6%/8%/15%/20%) were also assessed. Cell attachment ratio (defined as the ratio of cells attached on microcarrier to the total number of cells in the culture) on glass beads is much higher than that on Cytodex 3 and Hillex for both mixed cell population and cell fraction at Ficoll 15-20% interface. The h…