Controlled Architecture of Dual-Functional Block Copolymer Brushes on Thin-Film Composite Membranes for Integrated “Defending” and “Attacking” Strategies against Biofouling

We report a new macromolecular architecture of dual functional block copolymer brushes on commercial thin-film composite (TFC) membranes for integrated “defending” and “attacking” strategies against biofouling. Mussel-inspired catechol chemistry is used for a convenient immobilization of initiator molecules to the membrane surface with the aid of polydopamine (PDA). Zwitterionic polymer brushes with strong hydration capacity and quaternary ammonium salt (QAS) polymer brushes with bactericidal ability are sequentially grafted on TFC membranes via activators regenerated by electron transfer–atom transfer radical polymerization (ARGET-ATRP), an environmentally benign and controlled polymerization method. Measurement of membrane intrinsic transport properties in reverse osmosis experiments shows that the modified TFC membrane maintains the same water permeability and salt selectivity as the pristine TFC membrane. Chemical force microscopy and protein/bacterial adhesion studies are carried out for a comprehensive evaluation of the biofouling resistance and antimicrobial ability, demonstrating low biofouling propensity and excellent bacterial inactivation for the modified TFC membrane. We conclude that this polymer architecture, with complementary “defending” and “attacking” capabilities, can effectively prevent the attachment of biofoulants and formation of biofilms and thereby significantly mitigate biofouling on TFC membranes

Americium(III) Capture Using Phosphonic Acid-Functionalized Silicas with Different Mesoporous Morphologies: Adsorption Behavior Study and Mechanism Investigation by EXAFS/XPS

Efficient capture of highly toxic radionuclides with long half-lives such as Americium-241 is crucial to prevent radionuclides from diffusing into the biosphere. To reach this purpose, three different types of mesoporous silicas functionalized with phosphonic acid ligands (SBA-POH, MCM-POH, and BPMO-POH) were synthesized via a facile procedure. The structure, surface chemistry, and micromorphology of the materials were fully characterized by ³¹P/¹³C/²⁹Si MAS NMR, XPS, and XRD analysis. Efficient adsorption of Am­(III) was realized with a fast rate to reach equilibrium (within 10 min). Influences including structural parameters and functionalization degree on the adsorption behavior were investigated. Slope analysis of the equilibrium data suggested that the coordination with Am­(III) involved the exchange of three protons. Moreover, extended X-ray absorption fine structure (EXAFS) analysis, in combination with XPS survey, was employed for an in-depth probe into the binding mechanism by using Eu­(III) as a simulant due to its similar coordination behavior and benign property. The results showed three phosphonic acid ligands were coordinated to Eu­(III) in bidentate fashion, and Eu­(P­(O)­O)₃(H₂O) species were formed with the Eu–O coordination number of 7. These phosphonic acid-functionalized mesoporous silicas should be promising for the treatment of Am-containing radioactive liquid waste

Controlled Architecture of Glass Fiber/Poly(glycidyl methacrylate) Composites via Surface-Initiated ICAR ATRP Mediated by Mussel-Inspired Polydopamine Chemistry

This study presents a new strategy by integrating surface-initiated atom transfer radical polymerization (SI-ATRP) with bioinspired polydopamine chemistry to prepare well-defined glass fiber/polymer composites. First, a homogeneous PDA layer, which served as a favorable platform facilitating ATRP initiator anchoring, was deposited onto the glass fibers. Controlled growth of poly­(glycidyl methacrylate) (PGMA) brushes from the glass fibers was then performed using the initiators for continuous activator regeneration (ICAR) ATRP method. PGMA brushes with defined structure, grafting density (5 wt % to 25 wt %), and good preservation of chain-end functionality could be obtained by reducing radical initiator ratio and using a high dilution strategy (solvent:monomer = 10:1 (v:v)); and a narrow distribution of molecular weight (PDI ≤ 1.2) could be attained within reduced polymerization time. Laccase, as an enzyme model, was then covalently immobilized to the glass fiber/PGMA composites. The developed biocomposites showed improved enzymatic stability and enhanced catalytic activity toward the degradation of 2,6-dimethoxyphenol

XRCC1 Arg194Trp and Arg280His Polymorphisms Increase Bladder Cancer Risk in Asian Population: Evidence from a Meta-Analysis

<div><p>Background</p><p>A lot of studies have investigated the correlation between x-ray cross complementing group 1 (XRCC1) polymorphisms and bladder cancer risk, but the results in Asian population were still inconclusive. We conducted a meta-analysis to ascertain the association of XRCC1 Arg194Trp, Arg280His and Arg399Gln polymorphisms with bladder cancer risk in Asian population.</p><p>Methodology/Principal findings</p><p>The association strength was measured with odds ratios (ORs) and 95% confidence intervals (95% CIs). A total of 9 eligible studies, conducted in China, India and Japan, were identified. We observed a significant increased risk of bladder cancer in dominant model (OR = 1.199, 95% CI: 1.021,1.408, P_{heterogeneity} = 0.372), allele comparison (OR = 1.200, 95% CI: 1.057,1.362, P_{heterogeneity} = 0.107) of Arg194Trp, heterozygote comparison (OR = 1.869, 95% CI: 1.205,2.898, P_{heterogeneity} = 0.011) and dominant model (OR = 1.748, 95% CI: 1.054,2.900, P_{heterogeneity} = 0.01) of Arg280His. Pooled results estimated from adjusted ORs further validated these findings. No publication bias was detected. Subgroup analyses found that significant increased risk was only found among community-based studies not hospital-based studies. There was no evidence of publication bias.</p><p>Conclusion</p><p>This is the first meta-analysis conducted in Asian investigating the correlation between XRCC1 polymorphisms and susceptibility to bladder cancer. Our meta-analysis shows that XRCC1 Arg194Trp and Arg280His polymorphisms are associated with a significantly increased risk of bladder cancer in Asian population.</p></div

Forest plots for XRCC1 Arg194Trp polymorphism.

<p>A: dominant model: ArgTrp+TrpTrp vs. ArgArg; B: allele comparison: Trp vs. Arg.</p

Funnel plots for XRCC1 Arg194Trp (A, allele comparison: Trp vs. Arg) and Arg280His (B, heterozygote comparison: ArgHis vs. ArgArg).

<p>Funnel plots for XRCC1 Arg194Trp (A, allele comparison: Trp vs. Arg) and Arg280His (B, heterozygote comparison: ArgHis vs. ArgArg).</p

Forest plots XRCC1 Arg280His polymorphism.

<p>Heterozygote comparison (ArgHis vs. ArgArg) estimated with raw genotype frequencies (A) and adjusted odds ratios (B).</p

Flow Chart.

<p>Flow Chart.</p

Meta-analysis results of XRCC1 polymorphisms and bladder cancer risk.

<p>M1: homozygote comparison; M2: heterozygote comparison; M3: dominant model; M4: recessive model; M5: allele comparison; P: P value for heterogeneity; a estimated from adjusted ORs and 95% CIs; NA: not analyzed;</p>*<p>significant difference.</p

Characteristics of eligible studies.

<p>CB: community-based studies; HB: hospital-based studies.</p