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Oxygen evolution reaction on a graphene sheet at negative potential is observed using surface plasmon resonance microscopy (SPRM). It is found that oxygen nanobubbles are evolved at negative potential due to the disproportion reaction of superoxide originated from the reduced dissolved oxygen, suggesting that graphene acts as a superoxide dismutase (SOD) mimic. SPRM reveals that the catalytic sites distribute at the edge and the bulk of graphene. Atomic force microscopy suggests that the active sites for bubble evolution in the bulk of graphene are located at internal edge originated from the holes in the graphene rather than the metal oxide residues remained on the graphene sheet. The metal oxide nanoparticles on the graphene sheet are not the direct active sites but also play important roles in promoting the catalysis by increasing the superoxide concentration through an electrocatalyzed Fenton reaction. This work also presents the first experimental evidence that the catalysis of graphene is generated from the edge effect in an in operando manner. The SPRM represents a universal tool to reveal the catalytic mechanism at microscale, and it is hoped to discover more exciting reactions on nanomaterials due to its label free feature, high sensitivity, and versatility to most of materials. [Display omitted] • Oxygen evolution reaction was observed at negative potential on a graphene sheet. • This reaction was imaged at microscale in an in-operando manner. • The edge of the graphene is the active site for oxygent nanobubbles evolution. • The metal oxides on the graphene sheet are not the active sites, but promote this reaction. [ABSTRACT FROM AUTHOR]

Genetic factors have been shown to be associated with Myelodysplastic syndromes (MDS) susceptibility. In recent years, the role of inflammation in the promotion of tumor growth is supported by a broad range of experimental and clinical evidence. But the relationship between polymorphisms in NOD-like receptor protein 3 (NLRP3) inflammasome and MDS is rarely reported. Thus, we conducted a case-control study, and genotyped five single nucleotide polymorphisms (SNPs) (NLRP3, IL-1β, IL-18, CARD8, and NF-κB) in MDS patients and healthy controls. The association of different genotypes with patient characteristics was analyzed. Comparing MDS patients with controls, GG genotype of IL-1β (rs16944) was observed to be associated with a significantly increased risk of MDS 78/166 (48.8%) vs 26/96 (27.0%), OR = 2.1, CI (1.0–4.4). No significant association was identified regarding the rest of investigated polymorphisms and MDS susceptibility. Complex karyotypes were more frequent in patients with GG genotype of IL-1β (rs16944). Patients with IL-1β polymorphisms (rs16944) GG and GA had lower hemoglobin than those without. Patients with IL-1β polymorphisms (rs16944) GG had higher IPSS scores than those without IL-1β polymorphisms. In conclusion, our present data shows that the IL-1β polymorphisms (rs16944) GG were frequently occurred in MDS. IL-1β (rs16944) GG genotype might serve as a novel biomarker and potential targets for MDS. [ABSTRACT FROM AUTHOR]

Membranes with zwitterionic surfaces are highly desired in water-based separations for their distinguished fouling resistance. Herein, a facile strategy for the preparation of zwitterion-functionalized membranes is developed by coupling the pore-making and zwitterion functionalization in one step. We soaked thin films of poly (2-dimethylaminoethyl methacrylate)- block -polystyrene (PDMAEMA- b -PS) in the mixture of ethanol and 1, 3-propanesultone (1, 3-PPST). In this mixture, PDMAEMA microdomains were selective swollen leading to nanoporous structures with PDMAEMA chains enriched on the surface. Simultaneously, the quaternization reaction between PDMAEMA and 1, 3-PPST took place. Unexpectedly, in addition to function as the zwitterionic agent, 1, 3-PPST also contributed to the selective swelling induced pore generation. It was found that the presence of 1, 3-PPST in ethanol slowed down the swelling process at the early stage, but evidently enhanced the swelling of PDMAEMA- b -PS films in longer duration. Thus-prepared zwitterion-functionalized membranes exhibited several times higher water permeance than non-zwitterionized counterparts, which should be attributed to increased pore size and strongly improved hydrophilicity as a result of zwitterion functionalization. Moreover, the membranes showed exceptional fouling resistance because of the presence of zwitterions. Image 1 • Selective swelling and zwitterion functionalization are coupled into one step. • 1, 3-PPST works as both one component of the swelling agent and modifying agent. • Zwitterionic membranes exhibit excellent anti-fouling performance. • Separation performance can be facilely regulated by swelling durations. [ABSTRACT FROM AUTHOR]

Inspired by biological membranes with charge-gated channels that allow the transport of water and ions but restrict the undesired substances, various regulated nanofiltration (NF) membranes containing charge-gated channels have been developed for water purification. However, most of these membranes are mono-charged (positively or negatively) that show high rejection only to the corresponding co-ions but low rejection to the counter-ions, which limits their wider applications. Herein, we report NF membranes with gas-tunable charge-gated channels and high rejection to different salts on demand. The membranes are prepared by assembling a CO 2 -responsive polymer, poly(N,N-dimethylaminoethyl methacrylate), on the surface of graphene oxide (GO). As a result of CO 2 -induced reversal of the charge sign, the membranes exhibit "self-regulation" of their surface charges. Upon bubbling CO 2 into water, the membranes are positively charged, which shows high rejection to MgCl 2. After bubbling Ar to remove CO 2 , the membranes gradually transform to negatively charged, and high rejection to Na 2 SO 4 is obtained. This study demonstrates the gas-tunable charge-gated ion transport behavior of the CO 2 -responsive NF membranes, and opens up new avenues for the design of on-demand NF membranes. New nanofiltration membranes exhibit on-demand switchable rejections toward cations and anions with the participation and departure of CO 2. Image 1 • New nanofiltration membrane was built with graphene oxide and CO 2 -responsive polymer. • The surface of nanopores can be reversibly switched between opposite charged state. • Charge sign can easily be reversed in a robust and contamination-free manner. • Ion transport behavior was dominated with the participation and departure of CO 2. [ABSTRACT FROM AUTHOR]