A Versatile Approach for the Site‐Specific Modification of Recombinant Antibodies Using a Combination of Enzyme‐Mediated Bioconjugation and Click Chemistry

A unique two‐step modular system for site‐specific antibody modification and conjugation is reported. The first step of this approach uses enzymatic bioconjugation with the transpeptidase Sortase A for incorporation of strained cyclooctyne functional groups. The second step of this modular approach involves the azide–alkyne cycloaddition click reaction. The versatility of the two‐step approach has been exemplified by the selective incorporation of fluorescent dyes and a positron‐emitting copper‐64 radiotracer for fluorescence and positron‐emission tomography imaging of activated platelets, platelet aggregates, and thrombi, respectively. This flexible and versatile approach could be readily adapted to incorporate a large array of tailor‐made functional groups using reliable click chemistry whilst preserving the activity of the antibody or other sensitive biological macromolecules.     

Travelling waves near a critical point of a binary fluid mixture

Travelling waves of densities of binary fluid mixtures are investigated near a critical point. The free energy is considered in a non-local form taking account of the density gradients. The equations of motions are applied to a universal form of the free energy near critical conditions and can be integrated by a rescaling process where the binary mixture is similar to a single fluid. Nevertheless, density solution profiles obtained are not necessarily monotonic. As indicated in Appendix, the results might be extended to other topics like in finance or biology.     

Variations on (0, s)-Sequences

In the first part of this paper, after a survey on the general theory of (t, s)-sequences, we review the main constructions of (0, s)-sequences and point out some relations between them. From these comparisons and from examples we have met in another context, we have found new (0, s)-sequences in prime base b to which the second part is devoted; the proofs are based on the general framework of formal Laurent series introduced by Niederreiter; the construction can be randomized and should have numerical applications.     

Hydroxy and Di-Hydroxy End-Capped Polybutadiene as Reactive Steric Stabilizers for the Synthesis of Polyurethane Particles in Organic Dispersant Media

Summary: The synthesis of polyurethane particles by polyaddition of ethylene glycol (EG) and tolylene-2,4-diisocyanate (TDI) in cyclohexane at 60 °C was investigated in the presence of ω-hydroxy and ω,ω′-dihydroxy polybutadiene, used as reactive steric stabilizers. The effect of the functionality and concentration of the reactive polybutadiene, as well as the monomer addition procedure, onto the polyurethane particle formation was studied. Calibrated PUR particles with an average diameter in the range 1–2 µm could be readily obtained.     

On the Distribution of the Sums of Binomial Coefficients Modulo a Prime

 Let be the binomial coefficient modulo b (b prime), with if l is greater than c, and let be the sum of binomial coefficients modulo b, that is (mod b). We prove the following property: the for which the couples c, l verify and are uniformly distributed in the residue classes modulo b as n tends to infinity. The method, using the Perron-Frobenius theory, applies also to and gives a new proof of the well known result for the non-zero binomial coefficients modulo b. (Received 21 June 1999; in revised form 13 July 2000)     

Influence of Alkylaluminium Activators and Mixtures thereof on Ethylene Polymerization with a Tridentate Bis(imino)pyridinyliron Complex

The effect of various alkylaluminium compounds and their mixtures on ethylene polymerization catalyzed with a tridentate bis(imino)pyridinyliron catalyst is studied. Triethylaluminium and trihexylaluminium are good cocatalysts but yield polyethylenes with broad molar mass distribution (MMD) whereas triisobutylaluminium, a less efficient activator, gives polyethylenes with unimodal and narrow MMD. Specific mixtures of branched and linear alkylaluminium compounds yield highly active catalytic systems and polyethylenes with unimodal and tunable MMD.

SEC traces of PE prepared with iron catalyst and (1) TEA, (2) TiBA, and (3) THA (Al/Fe = 250) as cocatalysts.