Coated particles oxide

The small (10 -lm) coating particles are typically aluminum oxide [1344-28-1/, Al O. These particles can have BET surface areas of 100 to 300 m /g. The thermal and physical properties of alumina crystalline phases vary according to the starting phase (aluminum hydroxide or hydrate) and thermal treatment (see ALUMINUM COMPOUNDS, ALUMINUM OXIDE). 

In a modified preparation of phenyllithium, bromobenzene was added to finely powdered lithium (rather than coarse particles) in ether. The reaction appeared to be proceeding normally, but after about 30 min it became very vigorous and accelerated to explosion. It was thought that the powdered metal may have been partially coated with oxide or nitride which abraded during stirring, exposing a lot of fresh metal surface on the powdered metal. 

Coated particles are of interest for investigations involving catalysis, medicine and pigment production. The coatings which can be used to modify the properties of the underlying Fe oxide, may consist of a continuous, uniform shell around the core particle, or may be made up of very small particles that adhere to the core. 

Figure 1.1.20 shows the differential thermal analysis (DTA) data for the cores, of chromium hydrous oxides particles prepared in the absence of hematite, and of coated particles. It is obvious that the latter behave as the coating material, when alone. This example clearly indicates the possibility of having the surface site characteristics of chromium hydrous oxide induced onto ellipsoidal iron oxide particles. The latter morphology cannot be achieved by diiecl precipitation of the same chromium compound. 

In the two-layer model of a catalytic coating, soot particles oxidize when found within the field of catalyst action . This is modeled with a parameter... 

Weissleder et al. [84] first showed that the human transferrin receptor (hTfR) can be used to internalize MRI contrast agents. The hTfR regulates cellular uptake of iron from transferrin, a plasmatic iron transport protein [85], via a receptor mediated endocytosis mechanism. Thus, MION particles (dextran coated iron oxide) were oxidized with sodium periodate. Holotransferrin was added and the resulting Schiff base adduct was reduced with sodium cyanoborohydride to give transferrin labeled MIONs, Tf-MION (Scheme 3). 

In a later study, Pfeifer et al. [30] prepared Pd/Zn catalysts by both pre- and postimpregnation of wash-coated zinc oxide particles with palladium and compared their performance in methanol steam reforming. The catalytic performance of the samples was tested at a 250 °C reaction temperature, 3 bar pressure, a S/C ratio of two and 250 ms residence time. The WHSV amounted as 0.3 Ndm3 (min gcat) 1. The thickness of the coatings was calculated to 20 pm. The formation of the PdZn alloy was proven to occur at temperatures exceeding 200 °C by XRD measurements. 

Similar properties to the much more widely investigated sodium amide, but may be expected on general grounds to be more violently reactive. The frequent fires or explosions observed during work-up of reaction mixtures involving the amide were attributed to presence of unreacted (oxide-coated) particles of potassium in the amide solution in ammonia. A safe filtration technique is described.2... 

The first clinical human trials using magnetic hyperthermia were reported by Liibbe, et al. [70, 129, 137, 190] who used 100-nm starch-coated iron-oxide particles bound with epirubicin for treatment of advanced solid cancers. Jordan recently reported positive results from ongoing trials of advanced cancer patients who received magnetic nanoparticle hyperthermia in conjunction with conformal external beam radiation therapy [191]. The therapy was well tolerated by the patients and significant increases in the length and quality of life were observed. 

The most common metal swarfs are iron-based [9,10] and produced by the machine tool and automobile industries. The resulting fine Fe particles oxidize in storage and form magnetite and hematite. Because they also contain flammable machine oils, this oxidation makes them pyrophoric and hence a liability. Because the particle surfaces are coated with oil, they cannot be incorporated in conventional cement. As demonstrated by Wagh and Jeong [3], the acid phosphate in the CBPC process acts like a detergent and exposes the surface of these particles to the acid-base reaction and binds them. 

---