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Vitrimers have shown advantages over conventional thermosets via capabilities of dynamic network rearrangement to endow repairability as well as recyclability. Based on such characteristics, vitrimers have been studied and have shown promises as a 3D printing ink material that can be recycled with the purpose of waste reduction. However, despite the brilliant approaches, there still remain limitations regarding requirement of new reagents for recycling the materials or reprintability issues. Here, a new class of a 4D printable vitrimer that is translated from a commercial poly(ε‐caprolactone) (PCL) resin is reported to exhibit self‐healability, weldability, reprocessability, as well as reprintability. Thus, formed 3D‐printed vitrimer products show superior heat resistance in comparison to commercial PCL prints, and can be repeatedly reprocessed or reprinted via filament extrusion and a handheld fused deposition modeling (FDM)‐based 3D printing method. Furthermore, incorporation of semicrystalline PCL renders capabilities of shape memory for 4D printing applications, and as far as it is known, such demonstration of FDM 3D‐printed shape memory vitrimers has not been realized yet. It is envisioned that this work can fuel advancement in 4D printing industries by suggesting a new material candidate with all‐rounded capabilities with minimized environmental challenges., A widely utilized commercial 3D printing resin poly(ε‐caprolactone) (PCL) is translated into a PCL‐based vitrimer via end‐group crosslinking and transesterification‐based vitrimerization. The formed vitrimer enables dynamic network rearrangement for self‐healing, welding, reprocessing, and viscoelastic flowing. Furthermore, endowed mechanical strength and shape memory effects in comparison to the commercial PCL resin open up a new era for multifunctional fused deposition modeling (FDM)‐based 4D printing.

The ywpF gene (SAV2097) of the Staphylococcus aureus strain Mu50 encodes the YwpF protein, which may play a role in antibiotic resistance. Here, we report the first crystal structure of the YwpF superfamily from S. aureus at 2.5-A resolution. The YwpF structure consists of two regions: an N-terminal core β-barrel domain that shows structural similarity to type VI secretion system (T6SS) proteins (e.g., Hcp1, Hcp3, and EvpC) and a C-terminal two-helix pair. Although the monomer structure of S. aureus YwpF resembles those of T6SS proteins, the dimer/tetramer model of S. aureus YwpF is distinct from the functionally important hexameric ring of T6SS proteins. We therefore suggest that the S. aureus YwpF may have a different function compared to T6SS proteins. Proteins 2015; 83:781–788. © 2015 Wiley Periodicals, Inc.

A series of branched polymers for chemically amplified resists (CARs) were prepared through the reversible addition–fragmentation chain-transfer (RAFT) copolymerization of three monomers with lithographic functionalities and an acid-cleavable dimethacrylate monomer. The three monomers with lithographic functionalities were 2-ethyl-2-adamantyl methacrylate, α-γ-butyrolactone methacrylate, and 3-hydroxy-1-adamantyl methacrylate. The acid-cleavable monomer was 2,5-dimethyl-2,5-hexanediol dimethacrylate (DMHDMA), and 2-cyanoprop-2-yl-1-dithionaphthalate was used as a chain-transfer agent. Because DMHDMA contains two methacrylate groups, it induced the branched structures of the polymers. The degree of branching could be controlled by the molar fraction of DMHDMA in the monomer mixtures. The size and structure of the polymers obtained after hydrolysis were very close to those of linear polymers prepared by RAFT copolymerization with the same amount of reagents, only without the acid-cleavable monomer. A preliminary lithography test using an argon fluoride source demonstrated that the acid-cleavable branched polymers could be promising candidates for CAR materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Vibrio anguillarum, an opportunistic fish pathogen, is the main species responsible for vibriosis, a disease that affects feral and farmed fish and shellfish, and causes considerable economic losses in marine aquaculture. In this study, we used polymerase chain reaction (PCR) to detect V. anguillarum. PCR specificity was evaluated by amplifying the rpoS gene, a general stress regulator, in six strains of V. anguillarum and 36 other bacterial species. PCR amplified a species-specific fragment (689 bp) from V. anguillarum. Furthermore, the PCR assay was sensitive enough to detect rpoS expression from 3 pg of genomic DNA, or from six colony-forming units (CFU) mL(-1) of cultured V. anguillarum. However, the assay was less sensitive when genomic DNA from the infected flounder and prawn was used (limit of detection, 50 ng and 10 ng g(-1) tissue, respectively). These data demonstrate that PCR amplification of the rpoS gene is a sensitive and species-specific method to detect V. anguillarum in practical situations.

The membrane filtration process has received much attention as one of the most promising water purification techniques. However, it still has several disadvantages, such as organic-, oil-, and biofouling, membrane contamination by microorganisms, and the difficulty in rejecting heavy metal ions, which are closely related to the membrane surface properties. Various approaches have been used to prepare membranes with antifouling, antimicrobial, or heavy metal ion removal properties on their surfaces. However, membranes with all these properties have not yet been reported. It might be possible to prepare membranes with such multifunctional properties by modifying the membrane surfaces with various organic and/or inorganic functional materials using multiple chemical/physical modification procedures, though the process should be very tedious, costly, and time consuming. Here, a multifunctional filtration membrane is prepared by a rapid one-step assembly coating of tannic acid and iron ion (FeIII) on a commercial poly(ether sulfone) membrane. The catechol- and gallol-rich surfaces combine all of the desirable properties such as antifouling against proteins, oils, and microorganisms, as well as antimicrobial and heavy metal ion removal properties. This study provides a facile approach to prepare multifunctional filtration membranes that have potential applications in practical water purification.