A method is developed to enable emulsion polymerization to be performed under RAFT control to give living character without the problems that often affect such systems:  formation of an oily layer, loss of colloidal stability, or loss of molecular weight control. Trithiocarbonate RAFT agents are used to form short stabilizing blocks from a water-soluble monomer, from which diblocks can be created by the subsequent polymerization of a hydrophobic monomer. These diblocks are designed to self-assemble to form micelles. Polymerization is initially performed under conditions that avoid the presence of monomer droplets during the particle formation stage and until the hydrophobic ends of the diblocks have become sufficiently long to prevent them from desorbing from the newly formed particles. Polymerization is then continued at any desired feed rate and composition of monomer. The polymer forming in the reaction remains under RAFT control throughout the polymerization; molecular weight polydispersities are generally low. The number of RAFT-ended chains within a particle is much larger than the aggregation number at which the original micelles would have self-assembled, implying that in the early stages of the polymerization, there is aggregation of the micelles and/or migration of the diblocks. The latexes resulting from this approach are stabilized by anchored blocks of the hydrophilic monomer, e.g., acrylic acid, with no labile surfactant present. Sequential polymerization of two hydrophobic monomers gives completely novel core−shell particles where most chains extend from the core of the particles through the shell layer to the surface.

A new method is described, based on living amphipathic random macro-RAFT copolymers, which enables the efficient polymeric encapsulation of both inorganic and organic particulate materials via free-radical polymerization. The mechanism for this new approach is examined in the context of the polymer coating of zirconia- and alumina-coated titanium dioxide particles and its breadth of application demonstrated by the coating of organic phthalocyanine blue pigment particles. The particulate materials were first dispersed in water using a macro-RAFT copolymer as a stabilizer. Monomer and water-soluble initiator were then added to the system, and the monomer polymerized to form the coating. If nucleation of new polymer particles in the aqueous phase was to be avoided, it was found necessary to use a macro-RAFT copolymer that did not form micelles; within this constraint, a broad range of RAFT agents could be used. The macro-RAFT agents used in this work were found not to transfer competitively in the aqueous phase and therefore did not support growth of aqueous-phase polymer. Successful encapsulation of particles was demonstrated by TEM. The process described enables 100% of the particles to be encapsulated with greater than 95% of the polymer finishing up in the polymeric shells around the particles. Moreover, the coating reaction can be carried out at greater than 50% solids in many cases and avoids the agglomeration of particles during the coating step.

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OBJECT The authors present a retrospective cohort study examining complications in patients undergoing surgery for craniosynostosis using both minimally invasive endoscopic and open approaches. METHODS Over the past 10 years, 295 nonsyndromic patients (140 undergoing endoscopic procedures and 155 undergoing open procedures) and 33 syndromic patients (endoscopic procedures in 10 and open procedures in 23) met the authors’ criteria. Variables analyzed included age at surgery, presence of a preexisting CSF shunt, skin incision method, estimated blood loss, transfusions of packed red blood cells, use of intravenous steroids or tranexamic acid, intraoperative durotomies, procedure length, and length of hospital stay. Complications were classified as either surgically or medically related. RESULTS In the nonsyndromic endoscopic group, the authors experienced 3 (2.1%) surgical and 5 (3.6%) medical complications. In the nonsyndromic open group, there were 2 (1.3%) surgical and 7 (4.5%) medical complications. Intraoperative durotomies occurred in 5 (3.6%) endoscopic and 12 (7.8%) open cases, were repaired primarily, and did not result in reoperations for CSF leakage. Similar complication rates were seen in syndromic cases. There was no death or permanent morbidity. Additionally, endoscopic procedures were associated with significantly decreased estimated blood loss, transfusions, procedure length, and length of hospital stay compared with open procedures. CONCLUSIONS Rates of intraoperative durotomies and surgical and medical complications were comparable between endoscopic and open techniques. This is the largest direct comparison to date between endoscopic and open interventions for synostosis, and the results are in agreement with previous series that endoscopic surgery confers distinct advantages over open surgery in appropriate patient populations.

Summary: Controlled radical polymerization using RAFT has the potential to make polymers with virtually any desired molecular architecture. For this to be implemented on an industrial scale, it must be performed by polymerization in disperse media. However, simply adding a RAFT agent to a conventional emulsion polymerization recipe leads to a loss of molecular weight control and formation of coagulum, probably because of nucleation in droplets, which is normally an unlikely phenomenon in emulsion polymerizations. Recently, a method has been devised for implementing RAFT in ab initio emulsion polymerization that avoids droplets in the particle formation stage. The molecular weight distribution of the polymer thus formed shows that molecular weight control is maintained throughout the polymerization. A model is developed to predict the particle size formed in this new type of emulsion polymerization. The new methodology enables synthesis of novel dispersions where molecular architecture can be precisely controlled, such as structured core-shell particles.

Reversible addition fragmentation chain transfer (RAFT) polymerizations of styrene and methyl methacrylate were performed in bulk at 60°C, using cumyl dithiobenzoate as the mediating RAFT agent that has been immobilized via the stabilizing Z‐group to nanometer‐sized fumed silica particles. Increasing molecular weights with monomer conversion and absence of conventional polymerization activity in the interstitial solution phase were observed when the overall concentration of silica particles was carefully balanced with their respective cumyl dithiobenzoate loading. After completion of the polymerization, potentially sulfur‐free polymers with controlled molecular weights were obtained, initially via collecting the terminated polymeric material from the interstitial solution phase and, secondly, via cleavage of the surface‐confined polymer by a single addition fragmentation chain transfer step, which provides a pathway for recovery of the solid‐supported RAFT agent. Copyright © 2006 John Wiley & Sons, Ltd.

False positive diagnosis of epilepsy is common, even though there is considerable heterogeneity across studies. All potential imitators should be considered and clinicians should be cautious introducing AEDs without a definite diagnosis given the risk of side effects, and the possible impact on legal driving status and employment.

Our retrospective series shows that endoscopic and open repairs of metopic craniosynostosis are equivalent in improving hypotelorism and trigonocephaly at 1-year follow-up. Additional studies are necessary to better define minor differences in morphology, which may result from the different techniques.