Molecular clumps

Micromixing Mixing among molecules of different ages (i.e., mixing between macrofluid clumps). Mixing on a scale smaller tlian tlie minimum eddy size or minimum striation diickness by molecular diffusion. 

Heparin-induced thrombocytopenia A clinical syndrome of IgG antibody production against the heparin-platelet factor 4 complex occurring in approximately 1% to 5% of patients exposed to either heparin or low-molecular-weight heparin. Heparin-induced thrombocytopenia results in excess production of thrombin, platelet aggregation, and thrombocytopenia (due to platelet clumping), often leading to venous and arterial thrombosis, amputation of extremities, and death. 

The structure of proteins determines their function and can be described on four levels, illustrated on page 447. The primary structure is the sequence of amino acids in the polypeptide chain. The secondary structure describes how various short portions of a chain are either wrapped into a coil called an alpha helix or folded into a thin pleated sheet. The tertiary structure is the way in which an entire polypeptide chain may either twist into a long fiber or bend into a globular clump. The quaternary structure describes how separate proteins may join to form one larger complex. Each level of structure is determined by the level before it, which means that ultimately it is the sequence of amino acids that creates the overall protein shape. Fhis final shape is maintained both by chemical bonds and by weaker molecular attractions between amino acid side groups. 

Precollapse cloud cores are composed of cold molecular gas with ternperamres in the range 7 -15 K, and with gas densities —10 -10 mol cm (Figure 1). Some clouds may be denser yet, but this is hard to determine because of the limited density ranges for which suitable molecular tracers are abundant (typically isotopes of carbon monoxide and ammonia). Masses of these clouds range from roughly a solar mass to thousands of solar masses, with the distribution of clump masses fitting a power-law such that most of the clumps are of low mass, as is also true of stars in general. The cloud properties described below are used to constrain the initial conditions for hydrodynamic models of the collapse of cloud cores. 

Several implications can be drawn directly from Eq. (2-39). First, A // is always positive. Thus, the rule like attracts like, inferred from Eq. (2-30) for molecular mixtures, should also hold at the continuum level. Second, when dispersion forces are dominant, the Hamaker constant is small when ha= b—that is when the dispersed phase (A) has an index of refraction close to that of the medium (B), These rules also apply to molecular mixtures. Nevertheless, small molecules with a significant difference in index of refraction often mix because of the large entropy thereby gained. But particles lose too little entropy on coagulation to resist doing so when there is an attractive van der Waals interaction, and so particle-particle clumping is the norm in suspensions, unless countermeasures are taken to stop it (see Section 7.1). Analogous considerations explain the prevalence of phase separation in polymer blends (see Section 2.3.1.2). 

In Figure 2, kinetics of T2 removal using QAC treated beads is presented. It is obvious that the competitive adsorption between viruses and BSA molecules also reduced the adsorption rate. In both cases, viruses were inactivated rapidly at the initial 2 hour mark and titer reduction slowed down after that. This inconsistency with the first-order inactivation model may be due to various interfering mechanisms such as displacement, molecular orientation, multilayer effects, surface heterogeneity, and virion clumping. 

Restriction of high molecular weight DNA can be a problem since this DNA often aggregates and the inside of such clumps remains poorly accessible to enzymes. Prior to digestion, DNA is diluted to... 

In the equations presented above, the term fully mixed represents mixing at the molecular level. There is another mixing condition in which clumps or aggregates of molecules enter the reactor and flow through it without interacting with one another. Within each clump, however, there is complete mixing of molecules, and the residence time of each molecule is the same as that of... 

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