Resin-based microsphere

The second type of Y carrier is resin-based microspheres with a diameter of 29-35 pm and are also infused via the appropriate hepatic artery branch to provide selective internal radiation (SIR). These SIR-Spheres (Sirtex, Medical Limited) have an average activity of 40 Bq per sphere and can be suspended in sterile water and contrast media to the desired total activity [8,9j. Since the radioactive element is the same as that on glass microspheres. 

As described in the product insert, SIR-Spheres consist of biocompatible resin-based microspheres containing Y with a size between 20 and 40 microns in diameter. SIR-Spheres is a permanent implant and is provided in a vial with water for injection. Each vial contains 3 GBq of yttrium-90 (at the time of calibration) in a total of 5 cc water for injection. Each vial contains 40-80 million microspheres [25]. The corresponding activity per microsphere for SIR-Spheres is much lower than that of TheraSphere (50 Bq vs. 2500 Bq respectively) [24]. 

Hollow microspheres were developed by SOHIO Chem. Co. (1-5), and are produced by Emerson Cuming, Inc. Microballon is the trade name of a phenolic resin-based hollow microsphere produced by Emerson Cuming, Inc. and used to prevent evaporation in crude oil tanks. 

Phenolic Resin-Based Syntactic Foam. Powdered phenolic resin and phenolic resin microspheres are blended in a blender to make a flowable mixture, which is then poured into a mold and cured at 120°C for 2 hours. The resulting syntactic foam has a density of 0.16 to 0.24 g/cm. ... 

Chen et al. [19] have reported very active, stable platinum nanopartide catalysts prepared by alcohol reduction of PtCls using poly(N-isopropylacrylamide) previously grafted on PS microspheres as stabilizing polymer. The observed catalytic activity in the hydrogenation of allyl alcohol was more than five times higher than with Pt/C. Moreover, it was possible to recycle the resin-based catalysts for at least six cycles, whereas Pt/C was not recyclable at all. When comparing the catalytic activity of free and heterogeneous colloidal platinum particles, only a small decrease in the reaction rate was observed. 

Rane BR, Gujarathi NA, Patel JK. Biodegradable anionic acrylic resin based hollow microspheres of moderately water soluble drug rosightazone maleate Preparation and in vitro characterization. Drug Development and Industrial Pharmacy. December 2012 38(12) 1460-1469. PubMed PMID 22356275. 

Most of the reported data in the field were focused on epoxy resins based composites, either filled with microparticles, such as Ti02 containing pigments [213] and glass microspheres [214], or glass or carbon/graphite fiber reinforced [215-221]. 

Hodges et al. [152] and Bian and Cunningham [153] reported the grafting of PS, poly(acetoxystyrene), poly[styrene-b-(methyl methacrylate-co-styrene)], poly(acetoxystyrene-co-styrene), and poly(styrene-co-2-HEMA) copolymers onto 2,2,6,6-tetramethyl-l-piperidinyloxy nitroxide (TEMPO) bound Merrilield resin. Merrifield resin is a PS resin based on a copolymer of styrene and chloromethylstyrene cross-linked with divinylbenzene. In these works, a pronounced increase of particle size was observed, which was attributed to the formation of chains both at the surface and within the microspheres. The polymerization control was enhanced both on the surface and in solution by the addition of sacrificial nitroxide. 

In recent years, interesting works have been focused on the amino polysaccharide chitosan-based microspheres. The chitosan microspheres have been applied in diversified fields, such as food processing, water treatment and biological fields. To bring new or improved properties, the chemical modification of chitosan based microspheres is of rapidly growing interest. After chemical modification, chitosan based microspheres can be used as functional materials with modified properties, such as adsorption resins, magnetic resins and nanocomposites, for specific end use in food industry. This paper presents a review of the developments in the preparation and applications of chitosan-based microspheres. The main objective of this review is to provide recent information and to show the development trend about chitosan-based microspheres. 

Chitosan can dissolute in acidic solutions, so it is hard to recycle from acidic solution. It is thus necessary to stabilize it chemically for the recycling in acidic solutions. Several processes have been developed to stabilize chitosan, such as suspending cross-linked technique, emulsification technique and spray drying technique [10]. Through stabilization, chitosan can be prepared as microspheres, easily separated from solutions. To get new or improved properties, chitosan-based microspheres have been researched recently. In addition, to expend the range of chitosan applications, chitosan-based microspheres can be used as functional materials with modified properties, such as adsorption resins, magnetic resins and nanocomposites, etc. The preparation and application of different kinds of chitosan-based microspheres are reviewed in this paper. 

Table 10. Properties of syntactic prepregs based on epoxide resin and glass microspheres 127)... 

SMC based on hollow microspheres and polyester resin are being used in the manufacture of food containers for replacing aluminum containers46. ... 

A broad variety of particle sizes are available, from microspheres with less than 5-pm particle size up to resins of 700-pm particle size. The large beads can be used as polymeric microreactors.P l As the separation between resin and liquid is still performed by filtration, different glass filters have to be used the porosity and nominal pore size of these filters are listed in Table 5. In those applications where single beads are used (split/mix, single-bead analysis, bead-based assays) it is essential to know the capacity of the single beads. For practical purposes a correlation between bead size and capacity per bead is reported in Table 6. 

When a resin or heavy filler is replaced with the microspheres, most physical properties are reduced, based on constant volume (lower density). Stiffness is reduced, due to the resilient characteristics. Strength/weight ratio, fatigue, stress and resilience can offer useful product enhancement, with relatively small additions. 

Corrosion protection by ICPs has been well documented in several reviews [136-141]. The use of ICP-based core-shell latexes for the corrosion protection of steel is a relatively new field of research, and a recent review has proposed the exploitation of such possibihties [142]. In a recent study, we found that ICP-based core-shell latexes offer the possibility of achieving anticorrosion properties [143], though the presence of pinholes or scratches in the coatings enhances the corrosion rate of metals. This problem may be due to poor dispersion of the composite particles in the insulating resin systems, and future research will need to develop conductive polymer-based anticorrosive primers for metals. The anticorrosive properties of PANI-coated polystyrene latex microspheres has been reported recently [144]. PS-PANI composite particles with core-shell structure were prepared by chemical oxidative polymerization of anihne monomer in the presence of a PVP-stabilized PS latex suspension. The reduced form of the particle was obtained by adding hydrazine mono hydrate to the suspension. Both oxidized and reduced PANI-PS particles were used to obtain a PANI-PS-coated iron electrode (PANl-PS-Fe). Pure PANI... 

The dose calculation is based on the ratio of the tumor volume to the total liver volume, on the type of treatment (e.g., focal, lobar, whole liver), and whether resin or glass microspheres are used. To predict the distribution volume of the microspheres and to address the safety issues in terms of aberrant delivery, a pretreatment Tc MAA scan subsequent to the planning angiography is mandatory. 

In wastewater treatment, several investigations have reported about chitosan magnetic microspheres. Rorrer et al. prepared the porous-magnetic chitosan beads to remove of cadmium ions from waste water [62]. These beads can effectively remove Cd from waste water. The adsorption efficiency was influenced by the beads size. To improve uptake properties of metal ions, Zhou et al. prepared magnetic chitosan microspheres chemically modified with thiourea (TMCS). Compared to the unmodified ones, the uptake properties of metal ions such as Hg, Cu, and Ni ions was improved significantly. The adsorption kinetics followed the pseudo-second-order equation [63]. To improve the selectivity of metal ions, magnetic chitosan resin modified by Schiffs base derived from thiourea and... 

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