Relative reactivity of alkenyl alcohols in the palladium-catalyzed redox-relay Heck reaction

The relative rates of alkenyl alcohols in the Pd-catalyzed redox-relay Heck reaction were measured in order to examine the effect of their steric and electronic properties on the rate-determining step. Competition experiments between an allylic alkenyl alcohol and two substrates with differing chain lengths revealed that the allylic alcohol reacts 3–4 times faster in either case. Competition between di- and trisubstituted alkenyl alcohols provided an interesting scenario, in which the disubstituted alkene was consumed first followed by reaction of the trisubstituted alkene. Consistent with this observation, the transition structures for the migratory insertion of the aryl group into the di- and trisubstituted alkenes were calculated with a lower barrier for the former. An internal competition between a substrate containing two alcohols with differing chain lengths demonstrated the catalyst's preference for migrating toward the closest alcohol. Additionally, it was observed that increasing the electron-density in the arene boronic acid promotes a faster reaction, which correlates with Hammett [sigma-rho] values to give a [rho] of −0.87

Fast and Protecting-Group-Free Synthesis of (±)-Subincanadine C

The first total synthesis of (±)-subincanadine C has been accomplished in a protecting-group-free fashion. This pentacyclic indole alkaloid was synthesized in six steps from the known intermediate <b>4</b>, featuring Ni(COD)₂-mediated intramolecular Michael addition as a key transformation

Supplemental material for Adding dose modifications into Phase II and Phase II/III seamless trials

Supplemental Material for Adding dose modifications into Phase II and Phase II/III seamless trials by John Spivack, Bin Cheng and Bruce Levin in Statistical Methods in Medical Research</p

Fast and Protecting-Group-Free Synthesis of (±)-Subincanadine C

The first total synthesis of (±)-subincanadine C has been accomplished in a protecting-group-free fashion. This pentacyclic indole alkaloid was synthesized in six steps from the known intermediate <b>4</b>, featuring Ni(COD)₂-mediated intramolecular Michael addition as a key transformation

MiR-203 and miR-29 directly target VEGFA mRNA.

<p>(A) The predicted miR-203 and miR-29 targeting sequences located in the 3’-untranslated region (3’-UTR) of VEGFA mRNA. (B–C) Dual luciferase reporter assays were performed as described in <i>Materials and Methods</i> section. Cells were co-transfected with constructs containing the predicted targeting sequence (WT) or mutated targeting sequence (Mutant) cloned into the 3’-UTR of the reporter gene, along with miRNA mimics of miR-29 or miR-203. Mutation of the putative miR-203 binding site abolished the effect of miR-203 while leaving the action of all three miR-29 isoforms unaffected (B). Similarly, mutation of the putative miR-29 binding site abolished the action of the miR-29 isoforms (C). (D) Western blot analyses (upper panel) and qRT-PCR (lower) were performed to examine the effects of miRNA on VEGFA protein and gene expression in cells that were treated with miRNA mimics or control mimics. * Indicates significant differences between WT and Mutant group, ^# indicates significant differences between vector and each miRNA in WT cells (*, ^#. <i>p</i> < 0.05; ***, ^##<i>p</i> < 0.001). Data represent at least three independent experiments with similar results.</p

Oral palatal wound closure and serum corticosterone levels.

<p>(A) Closure of palatal wounds was significantly slower in isolated rats (ISO) than in group-housed rats (GRO). Compared with group-housed rats, a lower proportion of wounds were closed on days 7 and 8 in isolated rats (n=10/group; * <i>p</i><0.05, ** <i>p</i><0.01). (B) Serum corticosterone levels were significantly higher in isolated rats on days 1, 3 and 5 as compared to controls (n=5/group; * <i>p</i><0.05). BL: baseline.</p

Expression levels of healing-associated genes in isolated (ISO) and group-housed (GRO) rats on Days 1, 3 and 5 post-wounding.

<p>(A) IL1β; (B) MIP1α; (C) FGF7; (D) TNFα; and (E) VEGFA. Error bars represent SEM. * indicates a significant difference between stress conditions. ^# and ⁺ indicate significant differences between days within group-housed and isolated rats, respectively (n=10/group; *, ^#, ⁺, <i>p</i><0.05; **, ^{+ +}, ^##<i>p</i><0.01; ^###<i>p</i><0.001).</p

Expression of miR-29 family members, miR-203 and SOCS3 mRNA in wounded tissues by qRT-PCR.

<p>Relative expression levels of miR-29 family members (A) and miR-203 (B) in isolated (ISO) rats are in comparison to control levels expressed as 1 on the graph. U6 was used as an internal reference. (C) SOCS3 mRNA relative expression, GAPDH was used as a reference gene. (n=10/group [ISO&GRO], * indicates a significant difference between stress conditions. * <i>p</i><0.05; ** <i>p</i><0.01).</p

From Carbon-Encapsulated Iron Nanorods to Carbon Nanotubes

Carbon-encapsulated iron carbide/iron nanorods (CENRs) with length of 150−350 nm and diameter of 30−60 nm have been synthesized by co-carbonization of an aromatic heavy oil and ferrocene at 450 °C under autogenous pressure. The stability of CENRs heat-treated in air and nitrogen atmospheres was investigated. It was found that the as-grown nanorods were interestingly transformed into short carbon nanotubes by air oxidation and further heat treatment. The morphologies and structures of CENRs and derived nanotubes were investigated using transmission electron microscope, high-resolution transmission electron microscope, and X-ray diffraction measurements. In particular, the changes of iron distribution in carbon nanotubes after oxidation and carbonization were characterized by X-ray photoelectron spectroscopy. The results have shown that, after oxidation at 250 °C for 3 h, although the length and the diameter of CENRs remained unchanged, hollow carbon nanotubes with iron nanoparticles trapped inside became the main component. Then, by heat treatments at 500−550 °C and final 1000 °C in nitrogen atmosphere, completed carbon nanotubes were generated with the continued escape of the residual nanoparticles from carbon shells. The ejection mechanism of iron nanoparticles was discussed briefly

Switchable Giant Bulk Photocurrents and Photo-spin-currents in Monolayer PT-Symmetric Antiferromagnet MnPSe₃

Converting light into steady currents and spin-currents in two-dimensional (2D) platform is essential for future energy harvesting and spintronics. We show that the giant and modulable bulk photovoltaic effects (BPVEs) can be achieved in air-stable 2D antiferromagnet (AFM) monolayer MnPSe3, with nonlinear photoconductance >4000 nm·μA/V2 and photo-spin-conductance >2000 (nm·μA/V2ℏ/2e) in the visible spectrum. The propagation and the spin-polarizations of photocurrents can be switched via simply rotating the Néel vector. We unveil that the PT-symmetry, mirror symmetries, and spin–orbital-couplings are the keys for the observed sizable and controllable 2D BPVEs. All the results provide insights into the BPVEs of 2D AFM and suggest that the layered MnPSe3 is an outstanding 2D platform for energy device and photo-spintronics