Base particles

The particle size deterrnined by sedimentation techniques is an equivalent spherical diameter, also known as the equivalent settling diameter, defined as the diameter of a sphere of the same density as the irregularly shaped particle that exhibits an identical free-fall velocity. Thus it is an appropriate diameter upon which to base particle behavior in other fluid-flow situations. Variations in the particle size distribution can occur for nonspherical particles (43,44). The upper size limit for sedimentation methods is estabHshed by the value of the particle Reynolds number, given by equation 11 ... 

Superdex is a composite media of agarose and dextran. The base particle is formed of cross-linked agarose to which dextran is then covalently attached. The resulting family of Superdex-based gels has been constructed to provide... 

Engelhard s in-situ FCC catalyst technology is mainly based on growing zeolite within the kaolin-based particles as shown in Figure 3-9A. The aqueous solution of various kaolins is spray dried to form micR)spheres. The microspheres are hardened in a high-temperature l,3f)(TF/704°C) calcination process. The NaY zeolite is produced by digestion of the microspheres, which contain metakaolin, and mullite with caustic or sodium silicate. Simultaneously, an active matrix is formed with the microspheres. The crystallized microspheres are filtered and washed prior to ion exchange and any final treatment. 

Recently, a general method to prepare protein-based particles with tailored properties through MS sphere templating was reported [98]. In this approach, polyelectrolytes are infiltrated into the mesopores of MS spheres pre-loaded with... 

Bellocq NC, Pun SH, Jensen GS, Davis ME (2003) Transferrin-containing, cyclodextrin polymer-based particles for tumor-targeted gene delivery. Bioconjug Chem 14 1122-1132... 

Pun SH, Tack F, Bellocq NC, Cheng J, Grubbs BH, Jensen GS, Davis ME, Brewster M, Janicot M, Janssens B, Floren W, Bakker A (2004) Targeted delivery of RNA-cleaving DNA enzyme (DNAzyme) to tumor tissue by transferrin-modified, cyclodextrin-based particles. Cancer Biol Ther 3 641-650... 

A potential disadvantage of silica-based particles, however, is the tendency for the siloxane linkages between silicon atoms within the particle to dissolve hydrolytically, especially under... 

Polymeric-based particles have been utilized for the encapsulation and release of proteins and peptides for numerous applications. Recently,... 

Of course, the role of the artificially introduced stochastics for mimicking the effect of all eddies in a RANS-based particle tracking is much more pronounced than that for mimicking the effect of just the SGS eddies in a LES-based tracking procedure. In addition, the random variations may suffer from lacking the spatial or temporal correlations the turbulent fluctuations exhibit in real life. In RANS-based simulations, these correlations are not contained in the steady spatial distributions of k and e and (if applicable) the Reynolds stresses from which a typical turbulent time scale such as k/s may be derived. One may try and cure the problem of missing the temporal coherence in the velocity fluctuations by picking a new random value for the fluid s velocity only after a certain period of time has lapsed. 

The secondary structure, the mesopores, is similar to the internal structure of standard HPLC particles. This secondary structure provides the surface for retention. The standard pore size is in the order of 13 nm, resulting in a specific surface area of about 300 mVg. Due to the lower ratio of retentive structure to interstitial space, the retentivity of monoliths and the preparative loadability tends to be significantly lower than the retentivity and loadability of packed beds of 10-nm particles. Since the monolithic columns described here are made from silica, they can be derivatized in the same way and with the same technology as silica-based particles. Also, the useful pH range is the same as for silica-based particles. 

The aim of the research carried out in our laboratory was to develop a lipid formulation that could be manufactured by a simple and reproducible procedure. In particular, we wanted to produce phospholipid-based particles with a high AmB loading coupled to a small particle size. 

The design-base particle diameter to be separated in the vapor space should not exceed the pad-disengage-mt-nt droplet diameter. 1). To be on the safe side, a maximum droplet diameter should be limited to 400 pm. In horizontal drum design, the mesh pad should be regarded as a polisher for removing small droplets not separated in the vapor space—i.e., as a secondary mechanism in vapor-liquid separation... 

With the development of neutral hydrophilic methacrylates in Prague, originally for contact lens applications in the early 60 s113>, considerable interest was generated in the application of these materials in the cardiovasular environment. The qualitative argument was that such soft, water-rich surfaces must be relatively non-traumatic to proteins and cells. The development of neutral hydrophilic polysaccharide-based particles for protein chromatography in the late 60 s provided evidence that such surfaces do indeed show minimal binding of proteins. 

Beaudette TT, Cohen JA, Bachelder EM et al (2009) Chemoselective ligation in the functionalization of polysaccharide-based particles. J Am Chem Soc 131(30) 10360-10361... 

The matrices used in SEC are either polymeric or silica-based particles with a hydrophilic coating. The disadvantage of silica particles is that they tend to retain solutes by adsorption and may catalyze the degradation of solute molecules. To reduce adsorption, the surfaces of these particles are often modified by reaction with organic substituents. 

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