Preparation of macrodiols and polyols by chopping high‐molecular‐weight aliphatic polycarbonates

High‐molecular‐weight poly(1,4‐butylene carbonate) (PBC) (M_n: 40,000?90,000) was prepared through the condensation polymerization of dimethyl carbonate (DMC) and 1,4‐butanediol (BD) in the presence of 0.05 mol % sodium alkoxide catalyst. The subsequent feeding of 15 mol % HOAOH, such as 1,6‐hexanediol, 1,5‐pentanediol, 1,4‐cyclohexanedimethanol, or 1,4‐benzenedimethanol and stirring at 190–150 °C converted the extremely thick high‐molecular‐weight polymer to low‐molecular‐weight macrodiols with GPC‐measured M_n ～2000. The analysis of the ¹H NMR spectra indicated that the –A– units and 1,4‐butylene units were randomly distributed in the resulting oligomers. The chopping of the high‐molecular‐weight PBC using either triols or tetraols such as glycerol propoxylate, 1,1,1‐tris(hydroxymethyl)ethane, or pentaerythritol also afforded macropolyols containing branched chains with GPC‐measured M_n ～2000. When the chopped polymers were genuine PBCs, the resulting macrodiols or polyols were in a waxy state at room temperature. However, permanently oily compounds were obtained when the chopped polymers were prepared using 0.90 mole fraction of BD admixed with various other diols. The macrodiols and polyols synthesized in this study may have potential applications in the polyurethane industry. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1570–1580     

Polyimide incorporated cyanate ester/epoxy copolymers for high-temperature molding compounds

The rapid development of high-power devices has driven the requirement for high-temperature stable epoxy molding compounds. In this work, a designed polymer blend system consisting of cyanate ester/epoxy copolymers modified by polyimide (CE/EP-PI) has been studied. Polyimide used in this study has shown excellent dispersity in the cyanate ester and epoxy copolymer network (CE/EP), exhibiting homogeneous phase with a denser polymer network structure. With this polymer blend structure, CE/EP-PI system was proved to have a glass transition temperature as high as ~270 °C, increased modulus, and largely enhanced fracture toughness up to 2.06 MPa m^1/2. CE/EP-PI resins showed outstanding long-term stability at high temperature with low mass loss and increased fracture toughness after aging at 200 °C. This work provides a novel insight into the development of molding compounds based on polymer blends system with excellent high-temperature properties. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2412–2421     

Design and analysis of a low loss and large-tolerance optical interface for large-area optical waveguides

An alternative interface structure design of a large-area optical waveguide for a large-area optical printed circuit board using a step-out fabrication technique is proposed. To investigate the misalignment tolerances and coupling excess losses, we simulated and compared our proposed structure to a typical straight core structure. As a result, the proposed structure was found to significantly improve the misalignment tolerance by more than 2 times and successfully conduct a data-link based on large area optical waveguide of 50 cm ×?50 cm.     

Application of Sodium Dodecyl Sulfate-Capillary Gel Electrophoresis to the Characterization of Ricin A-Chain Immunotoxins

This study was undertaken to use sodium dodecyl sulfate-capillary gel electrophoresis (SDS-CGE) for the characterization of immunotoxins constructed by cross-linking ricin A-chain (RTA) to monoclonal antibody (MAb). SDS-CGE could separate mono- and di-RTA-conjugated MAbs from unreacted MAb, as identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Resolution of RTA-MAb conjugates was improved by decreasing the running voltage from 15 to 5 kV. SDS-CGE was also useful for characterizing aggregates of RTA or deglycosylated RTA (dgRTA) that was formed during immunotoxin preparation. Of the RTA isomers with different carbohydrate contents, RTA₁, which has low carbohydrate content, was found to be more susceptible to aggregation than RTA₂. In the SDS-CGE of dgRTA, both covalently and non-covalently linked aggregates were observed under reducing and non-reducing conditions. The findings of this study suggest that SDS-CGE can be used to optimize methods of preparing effective immunotoxins and for checking degradants and aggregates.

     

Differential responses of cancer cell lines to non-thermal plasma from dielectric barrier discharge

The differential responses of six cancer cell lines after treatment of non-thermal plasma from dielectric barrier discharge (DBD) were studied. Two plasma exposure methods including cell suspension exposure and media only exposure were used, and the effects were examined in six cancer cell lines including KB, MCF-7, HeLa, H460, SNU-80 and T98G from different human organs. The result indicates that both methods affected six cell lines similarly in proliferation, mitochondria activity, and apoptosis related gene expression, which implies that the cell culture media have significant role in plasma–cell interaction. H460 showed a significant reduction in cell number after plasma exposure, whereas MCF-7 showed less reduction. Mitochondria activity of all the cancer cell lines reduced following exposure and incubation times except MCF-7. The mRNA expression of Bax, the apoptosis related gene, was highly enhanced in KB, HeLa, MCF-7 and SNU-80, while none was detected in T98G. All six cancer cell lines showed unexpectedly low mRNA expression of tumor suppressor gene p53. These differential responses of six cell lines suggest that non-thermal plasma should activate different pathways in each cancer cell line. Further researches on tissue-specific responses to plasma treatment should be conducted, comparing their responses with normal tissue–cell responses.