Small macromolecular

M. Kubin, Small Macromolecular Monographs (Male Makromolekularni Monografie), Vol. 7, Institute of Macromolecular Chemistry, Czechoslovak Academy Sciences, Prague, 1970, pp. 1-38 (in Czech.). 

The SADMA option for the accommodation of small geometry variations is advantageous in studies of small macromolecular distortions, of protein folding processes, and potentially in the structure refinement process of x-ray structure determination. 

Devalues, obtained for PAr and PUAr poly condensation process, showed, that the indicated processes were realized by aggre tion cluster-cluster mechanism [49], i.e., by small macromolecular coils joining in larger ones [23], Thus, polycondensation process is a fractal object with dimension D. reaction. Such reaction can be presented schematically in a form of devil s staircase [80], Its horizontal parts correspond to temporal intervals, in which reaction is not realized. In this case polycondensation process is described with irsing fractal time t, which belongs to Kantor s set points [81], If polycondensation process is considered in Euclidean space, then time belongs to a real number set. 

The authors [10] used the considered above physical model for dimethyldial-lylammoniumchloride (DMDAACh) radical polymerization [1] description. As it was shown in work [8], the radical polymerization of DMDAACh was simulated by the diffusion-limited aggregation model according to mechanism cluster-cluster. This means, that the indicated process is realized by small macromolecular coils merging into larger ones. This treatment allows to simirlate DMDAACh polymerization as the Eq. (2) with the Eq. (4) or (6) depending on the space type, in which it is realized. In this case the value pA can be determined as follows [10] ... 

New mathematical techniques [22] revealed the structure of the theory and were helpful in several derivations to present the theory in a simple form. The assumption of small transient (elastic) strains and transient relative rotations, employed in the theory, seems to be appropriate for most LCPs, which usually display a small macromolecular flexibility. This assumption has been used in Ref [23] to simplify the theory to symmetric type of anisotropic fluid mechanical constitutive equations for describing the molecular elasticity effects in flows of LCPs. Along with viscoelastic and nematic kinematics, the theory nontrivially combines the de Gennes general form of weakly elastic thermodynamic potential and LEP dissipative type of constitutive equations for viscous nematic liquids, while ignoring inertia effects and the Frank elasticity in liquid crystalline polymers. It should be mentioned that this theory is suitable only for monodomain molecular nematics. Nevertheless, effects of Frank (orientation) elasticity could also be included in the viscoelastic nematody-namic theory to describe the multidomain effects in flows of LCPs near equilibrium. 

Furuyama T, Yonehara M, Arimoto S et al (2008) Development of highly chemoselective bulky zincate complex, Bu4ZnLi2 design, stmcture, and practical applications in small-/ macromolecular synthesis. Chem Eur J 14 10348-10356. doi 10.1002/chem.200800536... 

An alternative and much more flexible approach is represented hy the STAR file format [L48, 149, which can be used for building self-describing data files. Additionally, special dictionaries can be constructed, which specify more precisely the contents of the eorresponding data files. The two most widely used such dictionaries (and file formats) arc the CIF (Crystallographic Information File) file format [150] - the International Union of Crystallography s standard for representation of small molecules - and mmCIF [151], which is intended as a replacement for the PDB format for the representation of macromolecular structures,... 

A key factor determining the performance of ultrafiltration membranes is concentration polarization due to macromolecules retained at the membrane surface. In ultrafiltration, both solvent and macromolecules are carried to the membrane surface by the solution permeating the membrane. Because only the solvent and small solutes permeate the membrane, macromolecular solutes accumulate at the membrane surface. The rate at which the rejected macromolecules can diffuse away from the membrane surface into the bulk solution is relatively low. This means that the concentration of macromolecules at the surface can increase to the point that a gel layer of rejected macromolecules forms on the membrane surface, becoming a secondary barrier to flow through the membrane. In most ultrafiltration appHcations this secondary barrier is the principal resistance to flow through the membrane and dominates the membrane performance. 

One important class of integral equation theories is based on the reference interaction site model (RISM) proposed by Chandler [77]. These RISM theories have been used to smdy the confonnation of small peptides in liquid water [78-80]. However, the approach is not appropriate for large molecular solutes such as proteins and nucleic acids. Because RISM is based on a reduction to site-site, solute-solvent radially symmetrical distribution functions, there is a loss of infonnation about the tliree-dimensional spatial organization of the solvent density around a macromolecular solute of irregular shape. To circumvent this limitation, extensions of RISM-like theories for tliree-dimensional space (3d-RISM) have been proposed [81,82],... 

It is possible to go beyond the SASA/PB approximation and develop better approximations to current implicit solvent representations with sophisticated statistical mechanical models based on distribution functions or integral equations (see Section V.A). An alternative intermediate approach consists in including a small number of explicit solvent molecules near the solute while the influence of the remain bulk solvent molecules is taken into account implicitly (see Section V.B). On the other hand, in some cases it is necessary to use a treatment that is markedly simpler than SASA/PB to carry out extensive conformational searches. In such situations, it possible to use empirical models that describe the entire solvation free energy on the basis of the SASA (see Section V.C). An even simpler class of approximations consists in using infonnation-based potentials constructed to mimic and reproduce the statistical trends observed in macromolecular structures (see Section V.D). Although the microscopic basis of these approximations is not yet formally linked to a statistical mechanical formulation of implicit solvent, full SASA models and empirical information-based potentials may be very effective for particular problems. 

The highest probability paths will make the argument of the exponential small. That will be true for paths that follow Newtonian dynamics where mr = F(r). Olender and Elber [45] demonstrated how large values of the time step ht can be used in a way that projects out high frequency motions of the system and allows for the simulation of long-time molecular dynamics trajectories for macromolecular systems. 

Polymer supported reagents, catalysts, protecting groups, and mediators can be used in place of the corresponding small molecule materials (Sherrington, 1991 Sundell and Nasman, 1993). The reactive species is tightly bound to a macromolecular support which immobilizes it. This generally makes toxic, noxious, or corrosive materials much safer. The use of polystyrene sulfonic acid catalyst for the manufacture of methyl r-butyl... 

M. Daoud, P. G. de Gennes. Statics of macromolecular solutions trapped in small pores. J Physique 55 85-93, 1977. 

If a solution of protein is separated from a bathing solution by a semipermeable membrane, small molecules and ions can pass through the semipermeable membrane to equilibrate between the protein solution and the bathing solution, called the dialysis bath or dialysate (Figure 5A.2). This method is useful for removing small molecules from macromolecular solutions or for altering the composition of the protein-containing solution. 

On the basis of the above data it has been hypothesized that the conductivity of PFCM is due not to the contact between the filler particles but the current passes across the thin (less than 1 -2 microns) polymer interlayers. The conductivity arises when a spontaneous pressure exceeding the threshold value develops in the material. The overstresses apparently arise as a result of PP crystallization in the very narrow gaps between the filler particles [312], Since crystallization must strongly affect the macromolecular conformation whereas the narrowness of the gap and fixed position of molecules on the filler prevent it, the heat released in the process of crystallization must, in part, be spent to overcome this hindrance, whereby a local high pressure may arise in the gap. This effect is possible only where there are gaps of the size comparable with that of macromolecules. The small gap thickness will also hamper pressure relaxation, since the rate of flow from such a narrow clearance should be negligibly small. 

Center of mass or translational diffusion is believed to be the rate-determining step for small radicals33 and may also be important for larger species. However, other diffusion mechanisms are operative and are required to bring ihe chain ends together and these will often be the major term in the termination rate coefficient for the case of macromolecular species. These include ... 

There were essentially three reasons for this opposition. Firstly, many macromolecular compounds in solution behave as colloids. Hence they were assumed to be identical with the then known inorganic colloids. This in turn implied that they were not macromolecular at all, but were actually composed of small molecules bound together by ill-defined secondary forces. Such thinking led the German chemist C. D. Harries to pursue the search for the rubber molecule in the early years of the twentieth century. He used various mild degradations of natural rubber, which he believed would destroy the colloidal character of the material and yield its constituent molecules, which were assumed to be fairly small. He was, of course, unsuccessful. 

The simulation of macromolecular systems involves, in principle, the same difficulties as that of compounds of low-molecular mass, but the polymeric nature of the molecules tends to aggravate the computational problems faced by investigators of small molecules. 

Gohlke H, Klebe G. Approaches to the description and prediction of the binding affinity of small-molecule ligands to macromolecular receptors. Angew Chem Int Edit 2002 41 2645-76. 

Spliceosome The macromolecular complex responsible for precursor mRNA splicing. The spliceosome consists of at least five small nuclear RNAs (snRNA Ul, U2, U4, U5, and U6) and many proteins. 

Our standard incorporation assays contained resuspended particulate enzyme, labelled UDP-Gal (0.1 mM) and (10 mM) in resuspension buffer (Tris, pH 7.5). After incubation, reaction mixtures were heated briefly to 100°C and soluble lupin galactan was added, to ensure the precipitation of small amounts of galactan formed in the en me reaction and dissolved during the heating step. Precipitation of macromolecular products was achieved by adding methanol to a final concentration of 70%. The pellet was freed of soluble labelled products, including residual UDP-Gal, by repeated extraction with hot 70% methanol and was then analysed for labelled (l- )-P-D-galactan. The supernatant was analysed for soluble labelled products. 

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