Preparation of microporous polymers in the form of particles and a thin film from hyperbranched polyphenylenes

The use of a hyperbranched polymer as a building block for the synthesis of a microporous organic polymer was demonstrated. Hyperbranched polyphenylenes (HBPs) were prepared from (3,5‐dibromophenyl)boronic acid, which contained numerous unreacted bromophenyl end groups. Utilizing metal‐catalyzed coupling reactions between these functional groups, cross‐linked porous polymers were obtained. Although the HBPs did not show porosity, their cross‐linked polymers had highly porous structures with Brunauer–Emmett–Teller surface areas of up to 2030 m²/g. An insoluble porous thin film was fabricated by spin casting of a solution containing a HBP followed by Sonogashira cross‐coupling reaction. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2336–2342     

Overall approaches and experiences of first-time participants in the Nuclear Forensics International Technical Working Group’s Fourth Collaborative Material Exercise (CMX-4)

Journal of Radioanalytical and Nuclear Chemistry - The Fourth Collaborative Material Exercise (CMX-4) of the Nuclear Forensics International Technical Working Group (ITWG) registered the largest...     

A hybrid framework for optimizing beam angles in radiation therapy planning

The purpose of this paper is twofold: (1) to examine strengths and weaknesses of recently developed optimization methods for selecting radiation treatment beam angles and (2) to propose a simple and easy-to-use hybrid framework that overcomes some of the weaknesses observed with these methods. Six optimization methods—branch and bound (BB), simulated annealing (SA), genetic algorithms (GA), nested partitions (NP), branch and prune (BP), and local neighborhood search (LNS)—were evaluated. Our preliminary test results revealed that (1) one of the major drawbacks of the reported algorithms was the limited ability to find a good solution within a reasonable amount of time in a clinical setting, (2) all heuristic methods require selecting appropriate parameter values, which is a difficult chore, and (3) the LNS algorithm has the ability to identify good solutions only if provided with a good starting point. On the basis of these findings, we propose a unified beam angle selection framework that, through two sequential phases, consistently finds clinically relevant locally optimal solutions. Considering that different users may use different optimization approaches among those mentioned above, the first phase aims to quickly find a good feasible solution using SA, GA, NP, or BP. This solution is then used as a starting point for LNS to find a locally optimal solution. Experimental results using this unified method on five clinical cases show that it not only produces consistently good-quality treatment solutions but also alleviates the effort of selecting an initial set of appropriate parameter values that is required by all of the existing optimization methods.     

Synthesis of a versatile pentacyclic building block for organic electronics

A new pentacyclic building block, benzodibenzofuranquinone (BDBFQ), is synthesized in a single step from the inexpensive and readily available feedstocks chloranil and 3‐bromophenol. This versatile repeat unit is incorporated into a series of conjugated materials as either the redox active quinone form or as an electron‐rich dialkylated benzodibenzofuran (BDBF) unit. To illustrate the performance that can be obtained from these systems, optical and electrochemical properties were studied via UV–vis–NIR spectroscopy and cyclic voltammetry. Thin‐film morphology was characterized via grazing incidence wide‐angle X‐ray scattering with thin‐film field‐effect transistor measurements further demonstrating the utility of this system. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2618–2628