Labeled crosslinks

Neutron scattering experiments were also carried out on some model networks with labelled crosslinks, in the unswollen state13 26 To achieve such measurements the dry polystyrene networks are heated above their glass transition temperature, submitted to uniaxial deformation, quenched under stress and studied in the neutron scattering apparatus. 

ON THE EFFECT OF POSITIONAL ORDER ON THE SCATTERING BY COPOLYMERS AND NETWORKS WITH LABELED CROSSLINKS... 

In the frame of a mean-field approximation the intensity scattered by copolymers is evaluated taking into account the existence of correlations between the centers of the copolymer molecules. The results are discussed and extended to the case of networks with labeled crosslinks. 

Fig. 1. Scattering intensity (in arbitrary units) of a polystyrene network with labeled crosslinks (from ref.(2)). is the... 

Up to this time, it has not been possible to compare the results of experimental studies of elastic small angle neutron scattering (SANS) from polymer networks with labeled crosslinks with theoretical treatments of this scattering. This problem existed because polymer networks are essentially infinite in extent and an infinite sample is expected to... 

Shambaugh, N. Fujimori, E. Fluorescent-labeled crosslinks in collagen p5Tenebutyrylhydrazine. Biopolymers 1982,21,79-88. 

Several approaches have been disclosed to make release coatings that can be printed with ink jet or laser jet printers (e.g., to make linerless labels). For example, Khatib and Langan [164] disclose a blend of two different acrylate functional silicones, one with a high level of acrylate functionality to provide the printability and one with a low level of acrylate functionality to provide easy PSA release. Lievre and Mirou [165] describe an aqueous blend of a crosslinkable silicone and poly(vinyl alcohol-vinyl acetate) resins while Shipston and Rice describe a blend of acrylic resin and a surfactant [166]. 

Hot melt aerylie polymers for UV cure are generally of lower moleeular weight than their solution counterparts in order to maintain an aceeptable application viscosity. Consequently more crosslinks are needed to produce a complete network and thus peel and tack suffer to some degree. Nonetheless, several UV curable materials have been commercialized for PSA tapes and labels. 

The possibility of conformational changes in chains between chemical junctions for weakly crosslinked CP in ionization is confirmed also by the investigation of the kinetic mobility of elements of the reticular structure by polarized luminescence [32, 33]. Polarized luminescence is used for the study of relaxation properties of structural elements with covalently bonded luminescent labels [44,45]. For a microdisperse form of a macroreticular MA-EDMA (2.5 mol% EDMA) copolymer (Fig. 9 a, curves 1 and 2), as compared to linear PM A, the inner structure of chain parts is more stable and the conformational transition is more distinct. A similar kind of dependence is also observed for a weakly crosslinked AA-EDMA (2.5 mol%) copolymer (Fig. 9b, curves 4 and 5). 

Sodium dodecyl sulfate micelle 71,72,77,79 Spin label 139 Starch 100, 104 —, crosslinked 106 —, graft polymers 105, 107, 125, 127 Styrene 160—162 Styrene-divinylbenzene resins 167 Styrenesulfonic acid, copolymers 74—76 Surface area 147... 

Networks with labeled branch points have also been synthesized by anionic techniques. The crosslinks contain either ferrocene units 107) or lead, originating respectively from vinylferrocene or tetrakis[4(l-phenylvinyl)phenyl]plumbane 94). 

Amini, F., Denison, C., Lin, H.J., Kuo, L., and Kodadek, T., Using oxidative crosslinking and proximity labelling to quantitatively characterize protein-protein and protein-peptide complexes, Chem. Biol., 10(11), 1115-1127, 2003. 

Figure 8.20 (A) Generic chemical structure of the y-secretase inhibitors described by Seiffert et al. (2000). (B) y-Secretase inhibitor incorporating a benzophenone photoaffinity label for crosslinking studies.

Figure 31 compares the dynamic structure factors obtained from the crosslinks and the chain ends for two different Q-values. Without any analysis a strong reduction of the cross-link mobility compared to that of the chain end is obvious. A closer inspection also shows that the line-shape of both curves differs. While S(Q,t)/S(Q, 0) from the chain end decays continuously, S(Q,t) from the cross-links appears to decay faster at shorter than at longer times. This difference in line shape is quantified via the line shape parameter p. For the end-labelled chains, p is in close agreement with the p = 1/2 prediction of the... 

The size and shape of polymer chains joined in a crosslinked matrix can be measured in a small angle neutron scattering (SANS) experiment. This is a-chieved by labelling a small fraction of the prepolymer with deuterium to contrast strongly with the ordinary hydrogenous substance. The deformation of the polymer chains upon swelling or stretching of the network can also be determined and the results compared with predictions from the theory of rubber elasticity. 

Open-chain ligands were the first evaluated for complexation studies with indium and yttrium. The use of diethylenetriaminepentaacetic acid (DTPA) anhydride permitted early evaluation of labeled chelate-conjugates (Figure 2).80 The use of this activated chelating agent was quite popular, until the drawbacks associated with its crosslinking of proteins became apparent. 

Annexin V-functionalized crosslinked iron oxide (CLIO) was designed as a contrast agent for MRI, which was additionally labeled with Cy5.5 to allow colocalization with optical imaging techniques [98]. Alternatively, conjugation of multiple Gd-DTPA molecules or SPIO particles to the C2 domain of synaptotagmin I was shown to allow the detection of apoptotic cells in vitro [99]. Zhao et al. [100] were the first to apply a C2 domain-functionalized SPIO and showed very promising results for future in vivo applications of MR contrast agents for the detection of apoptotic sites. 

Chemical attachment of a detectable component to an oligonucleotide forms the basis for constructing a sensitive hybridization reagent. Unfortunately, the methods developed to crosslink or label other biological molecules such as proteins do not always apply to nucleic acids. The major reactive sites on proteins involve primary amines, sulfhydryls, carboxylates, or phenolates— groups that are relatively easy to derivatize. RNA and DNA contain none of these functionalities. 

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