Influence of pH and Oxidation State on the Interaction of Arsenic with Struvite During Mineral Formation

Struvite (MgNH₄PO₄·6H₂O) precipitated from animal and human wastes may be a sustainable source of fertilizer. However, arsenic, present in some wastes, may be removed with struvite. Here the sorption of As with struvite during mineral formation at pH 8–11 was assessed. The yield of struvite increased with pH, and was highest at pH 10. For recovered struvite, XRD indicated reduced crystallinity and particle size, and FT-IR suggested less distortion of phosphate tetrahedra with increased pH. The As impurity did not affect the crystallinity or particle size, but did contribute to phosphate distortion. Sorption of As­(V) was observed at all pH values, and was highest at pH 10. As­(III) sorption was consistently lower than that of As­(V), but increased with pH. XAFS suggested coprecipitation of As­(V), and adsorption of As­(III) as the potential sorption mechanisms. Solids derived from As­(III) solutions exhibited dual mechanisms due to the partial oxidation of As­(III) to As­(V) in solution prior to sorption. For struvite recovery in the presence of As, optimizing the pH to improve yields may increase the As content. Adsorbed As­(III) could be removed prior to fertilizer application, however coprecipitated As­(V) will release upon mineral decomposition, linking its cycling to that of phosphorus

Anisotropy of B‑DNA Groove Bending

DNA bending is critical for DNA packaging, recognition, and repair, and occurs toward either the major or the minor groove. The anisotropy of B-DNA groove bending was quantified for eight DNA sequences by free energy simulations employing a novel reaction coordinate. The simulations show that bending toward the major groove is preferred for non-A-tracts while the A-tract has a high tendency of bending toward the minor groove. Persistence lengths were generally larger for bending toward the minor groove, which is thought to originate from differences in groove hydration. While this difference in stiffness is one of the factors determining the overall preference of bending direction, the dominant contribution is shown to be a free energy offset between major and minor groove bending. The data suggests that, for the A-tract, this offset is largely determined by inherent structural properties, while differences in groove hydration play a large role for non-A-tracts. By quantifying the energetics of DNA groove bending and rationalizing the origins of the anisotropy, the calculations provide important new insights into a key biological process

sj-docx-2-pac-10.1177_18344909241226761 - Supplemental material for Sleep spindles consolidate declarative memory with tags: A meta-analysis of adult data

Supplemental material, sj-docx-2-pac-10.1177_18344909241226761 for Sleep spindles consolidate declarative memory with tags: A meta-analysis of adult data by Peiyao Chen, Chao Hao and Ning Ma in Journal of Pacific Rim Psychology</p

sj-docx-1-pac-10.1177_18344909241226761 - Supplemental material for Sleep spindles consolidate declarative memory with tags: A meta-analysis of adult data

Supplemental material, sj-docx-1-pac-10.1177_18344909241226761 for Sleep spindles consolidate declarative memory with tags: A meta-analysis of adult data by Peiyao Chen, Chao Hao and Ning Ma in Journal of Pacific Rim Psychology</p

VPA triggers Ca²⁺ influx via the Cch1-Yam8 channel complex.

<p>(A) The increase in the cytoplasmic Ca²⁺ level is derived from the extracellular medium. The experiment was performed as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068738#pone-0068738-g004" target="_blank">Figure 4</a>, expect that prior to the addition of 6 mM VPA, various concentrations of BAPTA (0.5, 1 and 2 mM) were added to chelate Ca²⁺ in EMM medium. The data are representative of six independent experiments. (B) The <i>cch1</i> deletion abolished VPA-induced Ca²⁺ influx. The Δ<i>cch1</i> cells harboring pKB6892 were cultured and assayed as described in the legend of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068738#pone-0068738-g004" target="_blank">Figure 4A</a>. The data are representative of six independent experiments. (C) The <i>yam8</i> deletion abolished VPA-induced Ca²⁺ influx. The Δ<i>yam8</i> cells harboring pKB6892 were cultured and assayed as described in the legend of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068738#pone-0068738-g004" target="_blank">Figure 4A</a>. The data are representative of six independent experiments. (D) The VPA-induced Ca²⁺ influx was observed in Δ<i>pmk1</i>. The Δ<i>pmk1</i> cells harboring pKB6892 were cultured and assayed as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068738#pone-0068738-g004" target="_blank">Figure 4A</a>. The data are representative of six independent experiments.</p

Ligand-Controlled Nickel-Catalyzed Reactions of Benzocyclobutenones with Alkynyltrifluoroborates: Diverse Construction of Polysubstituted Naphthols

Ligand-controlled nickel-catalyzed selective cleavage of the C1–C2 or C1–C8 bond of benzocyclobutenones (BCBs) is reported. The delicate selection of dpppe or PMe3 as the ligand led to predictably divergent synthesis of a wide range of 1-naphthols and 2-naphthols without C2 and C3 substituents, respectively, from BCBs and potassium alkynyltrifluoroborate, and the increase in the amount of PMe3 resulted in tandem reaction of 2 equiv of BCB with the borate to afford 3,4,5-trisubstituted 2-naphthols. The fabulous ligand effect resulted in the facile and unique construction of multisubstituted naphthols with well-controlled regioselectivity and a high degree of structural diversity

Alkaline-Metal-Promoted Divergent Synthesis of 1‑Aminoisoquinolines and Isoquinolines

Alkaline-metal-promoted divergent syntheses of 1-aminoisoquinolines and isoquinolines have been reported involving 2-methylaryl aldehydes, nitriles, and LiN(SiMe3)2 as reactants. In addition, the three-component reaction of 2-methylaryl nitriles, aldehydes, and LiN(SiMe3)2 has been developed to furnish 1-aminoisoquinolines. This protocol features readily available starting materials, excellent chemoselectivity, broad substrate scope, and satisfactory yields

FeCl₃‑Catalyzed Synthesis of Tanshinlactone Analogues from 1<i>H</i>‑Indene-1,2,3-triones and Alkynes

Tanshinlactone has been found in several natural products and biologically active compounds. Herein, a new FeCl3-catalyzed strategy using 1H-indene-1,2,3-triones and alkynes as starting materials is reported to obtain various tanshinlactone derivatives. This protocol has the advantages of involving low cost, environmentally benign catalysts, simple reaction conditions, and a broad range of substrates

Genome-Wide Screening for Genes Associated with Valproic Acid Sensitivity in Fission Yeast

<div><p>We have been studying the action mechanisms of valproic acid (VPA) in fission yeast <i>Schizosaccharomyces pombe</i> by developing a genetic screen for mutants that show hypersensitivity to VPA. In the present study, we performed a genome-wide screen of 3004 haploid deletion strains and confirmed 148 deletion strains to be VPA sensitive. Of the 148 strains, 93 strains also showed sensitivity to another aliphatic acids HDAC inhibitor, sodium butyrate (SB), and 55 strains showed sensitivity to VPA but not to SB. Interestingly, we found that both VPA and SB treatment induced a marked increase in the transcription activity of Atf1 in wild-type cells. However, in <i>clr6-1</i>, a mutant allele the <i>clr6⁺</i> gene encoding class I HDAC, neither VPA- nor SB induced the activation of Atf1 transcription activity. We also found that VPA, but not SB, caused an increase in cytoplasmic Ca²⁺ level. We further found that the cytoplasmic Ca²⁺ increase was caused by Ca²⁺ influx from extracellular medium via Cch1-Yam8 channel complex. Altogether, our present study indicates that VPA and SB play similar but distinct roles in multiple physiological processes in fission yeast.</p></div