Calcofluor White ST, stilbene derivative used commerically as an optical brightener for cellulose, increased the rate of glucose polymerization into cellulose by resting cells of the gram-negative bacterium Acetobacter xylinum. This bacterium normally produces a ribbon of cellulose that is a composite of crystalline microfibrils. In concentrations above 0.1 mM, Calcofluor disrupts the assembly ...

Fluorescent probes covalently bound to actin or to the actin binding protein, brevin, have been utilized to provide information about actin filaments formed in the presence of brevin as well as about the effect of brevin on the rate of polymerization. At actin to brevin ratios of 10:1 to 100:1, the observed diffusion coefficients of filaments, as measured by fluorescence photobleaching recovery...

Lamellipodium extension is crucial for cell migration and spreading. The rate of lamellipodium extension is determined by the balance between the rate of actin polymerization and the rate of actin retrograde flow. LIM kinase 1 (LIMK1) regulates actin dynamics by phosphorylating and inactivating cofilin, an actin-depolymerizing protein. We examined the role of LIMK1 in lamellipodium extension by...

polymerization of styrene in presence of two monofunctional initiators is studied kinetically in an ampoule scale. polymerizations were ceased at different conversions for each ampoule while the temperature was increased almost linearly during the reaction. three different initiator mixtures were used. the first mixtures were composed of benzoil peroxide (bpo) and t-butyl perbenzoate (tbpb) wit...

in current work a comprehensive mechanism based on intermediate radical termination theory is assumed for raft polymerization of styrene over cumyl dithiobenzoate as raft agent. rate constants for addition (ka) and fragmentation reactions (kf) are set to 6×106 and 5×104 respectively, which lead to an equilibrium constant value of k = ka/kf = 1.2 x 102. moment equations method was used to model ...

kinetics of radical polymerizations of waterborne alkyd/acrylic hybrid resin via batch mini-emulsion technique was studied using redox initiators (tbhp/fe2+/edta/asac  and  tbhp/fe2+/edta/sfs) at relatively low temperatures and thermal initiators (bpo, kps and aibn) at higher temperatures to seek the most suitable initiator system. at the end of all reactions the unreacted monomer content was r...

‎(St-co-BA) polymer through montmorillonite (MMT) nanocomposite emulsion is prepared by ‎in situ intercalative emulsion polymerization of styrene (St), butyl acrylate (BA) in the ‎presence of organic modified montmorillonite (OMMT) with different OMMT contents (0, ‎‎0.5, 1.0, 1.5, and 2.0 wt%). The synthetic compounds are characterized by FTIR, XRD. The ‎nanocomposite emulsions are characterize...

Photoinitiated polymerization of styrene in oil/water microemulsions has been successfully performed by using dibenzyl ketone (DBK) as initiator. The system remains transparent during the whole polymerization process. The molecular weights of polymers produced are in the order of IO5, and the polydispersity indexes (PDI) are in the range 1.6-2.2. The particle sizes of the latexes produced are i...

in atom transfer radical polymerization (atrp) of methyl acrylate (ma) with polyvinyl acetate macroinitiator in bulk at 90°c the plots of ln [m]0/[m] increased linearly with reaction time. the apparent propagation rate constant (kp app) of the reaction was obtained from the linear curve and used to calculate the free macroradical concentration ([r°]) in polymerization medium. the [r°] and also ...