Overlooked Role of Carbonyls of Natural Organic Matter on the Dissolution of Zinc Oxide Nanoparticles

Zinc oxide nanoparticles (ZnO NPs) are harmful because of the release of cytotoxic Zn2+ during dissolution. The dissolution process of ZnO NPs is affected by natural organic matter (NOM) in the water environment. In this study, we investigated the role of carbonyl functional groups of NOM isolates in the dissolution of ZnO NPs. Sodium borohydride (NaBH4) can selectively reduce the carbonyls in NOM. We treated seven types of NOMs with NaBH4. The experimental results show that the NOM treated by NaBH4 has a significantly reduced ability to dissolve ZnO NPs. A series of model aromatic ketones and quinones were used to simulate NOM, and these model small-molecule mixtures were selectively reduced by NaBH4 and sodium dithionite (Na2S2O4). The ability of the treated model small-molecule mixture to dissolve ZnO NPs was reduced. These results further demonstrate that carbonyls play an important role in the dissolution of ZnO NPs. The results of the study allow us to better understand the transfer process of ZnO NPs in NOM-rich aquatic environments

[Bmim]PF₆‑Promoted Ligandless Suzuki–Miyaura Coupling Reaction of Potassium Aryltrifluoroborates in Water

The Suzuki–Miyaura coupling reactions of potassium aryltrifluoroborates with aryl bromides in water are promoted by the addition of [bmim]­PF₆ using Pd­(OAc)₂ as a catalyst and Na₂CO₃ as a base under air. The quantity of [bmim]­PF₆ used is crucial to the efficiency of the catalytic system. A wide range of biaryls and polyaryls can be easily prepared in good to excellent yields

The collected <i>Ulva</i> blooming in the coastal waters of Qingdao, China on July, 2008.

<p>The collected <i>Ulva</i> blooming in the coastal waters of Qingdao, China on July, 2008.</p

Phylogenetic tree of the ML analysis inferred from the ITS regions of the LPP clade.

<p>Initial letters UL and UP in the strain codes stand for <i>U. linza</i> and <i>U. prolifera</i>, respectively. Detailed information of each strain is given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019371#pone-0019371-t001" target="_blank">Table 1</a>. Numerals at internal nodes are bootstrap values >50% for 100 replicates in ML analysis.</p

Decomposition of Hydrogen Peroxide Driven by Photochemical Cycling of Iron Species in Clay

The reactivity of iron-bearing clays to catalyze the decomposition of hydrogen peroxide (H2O2) under light irradiation was investigated. Free iron oxides and structural iron in clay octahedral lattice are contained simultaneously in montmorillonite K10 (MK10), a representative natural clay mineral. By pretreatment of clay with the particular method, the reactivities of the two kinds of iron species were differentiated. It was found that free iron oxides on clay surface efficiently catalyzed the decomposition of H2O2 under UV light irradiation but structural iron in the octahedral lattice showed poor reactivity. This was found to result from the difference in production of Fe(II) species under UV irradiation between iron oxides and structural iron. When photoreactive substances such as N,N-dimethylaniline (DMA), rhodamine B (RhB), or malachite green (MG) were introduced, structural iron was found to promote greatly the decomposition of H2O2. The reduction of clay iron(III) to iron(II) is essential for the decomposition of H2O2, which is achieved by light-induced ligand to metal charge transfer (for iron oxides) or organic matters donating electrons upon irradiation (for structural iron). The light-induced redox cycling of iron did not lead to the release of iron and decomposition of H2O2 primarily localized on the clay surface. This work implies that iron-bearing clays could be a sink of H2O2 in the environmental system

Unrooted maximum likelihood tree of the 5S rDNA spacer region of the LPP clade.

<p>Numerals at internal nodes are bootstrap values >50% for 100 replicates in ML analysis. As in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019371#pone-0019371-g003" target="_blank">Figure 3</a>, red lines indicate a sexual type, blue lines an asexual quadriflagellate type and green lines an asexual biflagellate type.</p

Origin of strains within the LPP clade used in this study.

<p>*Determined by culture morphology of branch absence (<i>U. linza</i>) or presence (<i>U. prolifera</i>).</p><p>**Originally collected thallus type. In sporophytes, male and female gametophytes were cultured for hybridization.</p><p>***Accession numbers are recorded in the GenBank sequence database.</p><p>****This ITS ribotype is completely identical to ones from the other Qingdao strains previously reported <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019371#pone.0019371-Leliaert1" target="_blank">[4]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019371#pone.0019371-Pang1" target="_blank">[19]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019371#pone.0019371-Liu3" target="_blank">[21]</a>.</p

Hybridization matrix among <i>Ulva linza</i>, <i>U. prolifera</i> and the Qingdao strains.

<p>+ = success of copulation, development of the isolated hybrid zygotes, and production of zoospores in the hybrid sporophytes, − = no observation of clumps or aggregations of mixed gametes.</p

Cultured young <i>Ulva</i> thalli.

<p>(A) <i>Ulva linza</i> (ULC631). (B) <i>U. prolifera</i> (UPE21). (C) The Qingdao strain. The scale bars represent 5 µm.</p

Additional file 1 of Regional anesthesia did not improve postoperative long-term survival of tumor patients: a systematic review and meta-analysis of randomized controlled trials

Additional file 1. PRISMA 2009 Checklist