On the Gas-Phase Co⁺-Mediated Oxidation of Ethane by N₂O: A Mechanistic Study

The potential energy surface (PES) corresponding to the Co⁺-mediated oxidation of ethane by N₂O has been investigated by using density functional theory (DFT). After initial N₂O reduction by Co⁺ to CoO⁺, ethane oxidation by the nascent oxide involves C–H activation followed by two possible pathways, i.e., C–O coupling accounting for ethanol, Co⁺-mediated β–H shift giving the energetically favorable product of CoC₂H₄⁺ + H₂O, with minor CoOH₂⁺ + C₂H₄. CoC₂H₄⁺ could react with another N₂O to yield (C₂H₄)­Co⁺O, which could subsequently undergo a cyclization mechanism accounting for acetaldehyde and oxirane and/or a direct H-abstraction mechansim for ethenol. Loss of oxirane and ethenol is hampered by respective endothermicity and high kinetics barrier, whereas acetaldehyde elimination is much energetically favorable. CoOH₂⁺ could facilely react with N₂O to form OCoOH₂⁺, rather than Co­(OH)₂⁺ or CoO⁺

Theoretical Investigation of the Reaction of Mn⁺ with Ethylene Oxide

The potential energy surfaces of Mn⁺ reaction with ethylene oxide in both the septet and quintet states are investigated at the B3LYP/DZVP level of theory. The reaction paths leading to the products of MnO⁺, MnO, MnCH₂⁺, MnCH₃, and MnH⁺ are described in detail. Two types of encounter complexes of Mn⁺ with ethylene oxide are formed because of attachments of the metal at different sites of ethylene oxide, i.e., the O atom and the CC bond. Mn⁺ would insert into a C–O bond or the C–C bond of ethylene oxide to form two different intermediates prior to forming various products. MnO⁺/MnO and MnH⁺ are formed in the C–O activation mechanism, while both C–O and C–C activations account for the MnCH₂⁺/MnCH₃ formation. Products MnO⁺, MnCH₂⁺, and MnH⁺ could be formed adiabatically on the quintet surface, while formation of MnO and MnCH₃ is endothermic on the PESs with both spins. In agreement with the experimental observations, the excited state a⁵D is calculated to be more reactive than the ground state a⁷S. This theoretical work sheds new light on the experimental observations and provides fundamental understanding of the reaction mechanism of ethylene oxide with transition metal cations

Analysis of Petroleum Aromatics by Laser-Induced Acoustic Desorption/Tunable Synchrotron Vacuum Ultraviolet Photoionization Mass Spectrometry

Laser-induced acoustic desorption coupled with tunable synchrotron vacuum ultraviolet photoionization mass spectrometry (LIAD/SVUVPI-MS) is employed to analyze aromatics prepared under different conditions from Lungu atmospheric residue (LGAR), i.e., the primary aromatics separated directly from LGAR, and the secondary aromatics after hydrogenation of LGAR and its resins. The mass spectra of the primary aromatics present a bimodal normal distribution in the range of 200–900 Da, in which the relative intensity of the two peaks changes significantly with the SVUV photon energies (9.0, 11.0, and 14.0 eV), indicating that at least two categories of compounds with different ionization energies (IEs) are included, i.e., polycyclic aromatics (IEs < 10.0 eV) in the mass range of 400–900 Da, and aliphatic and alicyclic compounds (IEs close to 11.0 eV) in 200–400 Da. Also detected in the aromatics are metalloporphyrins. Furthermore, the mass spectra of the secondary aromatics separated from LGAR and its resins at different hydrogenation temperatures (390, 400, 410, and 420 °C) are also recorded. The results indicate that the hydrogenation process, especially at higher temperatures, results in removal of alkyl-side and bridge chains in the aromatics, and the secondary aromatics from LGAR resins contain more alkyl side and bridge chains and metal compounds than those from LGAR

DVD687 and DVD688 show different mechanism of actions (MOAs).

<p>Apoptosis assay was used to analyze (A) N87 or (C) Calu-3 cells after DVD-Ig proteins, mAbs, or combination treatment. BrdU-incorporation assay was used to analyze (B) N87 or (D) Calu-3 cells after DVD-Ig proteins, mAbs, or combination treatment. Three independent experiments with triplicates were performed. One representative experiment is shown here. The error bars indicate standard deviation from the mean. p value was calculated via student T-test.</p

Anti-ErbB2 DVD-Ig proteins in cell signaling assay.

<p>(A) Calu-3 and (B) N87 cells were cultured in medium containing 1% FBS were treated with 100nM antibodies or DVD-Ig proteins for 30 minutes. Cells were lysed, proteins were separated on SDS-PAGE gels and analyzed via western blot. Three independent experiments were performed. One representative experiment is shown here.</p

Novel Two-Dimensional Metal Organic Frameworks: High-Performance Bifunctional Electrocatalysts for OER/ORR

For the development of energy storage and conversion, it is essential to explore high performance bifunctional catalysts with oxygen reduction and evolution reaction (ORR and OER). Two-dimensional (2D) metal–organic frameworks (MOFs) with abundant exposed active sites have great potential as catalyst materials with high electrocatalytic activity. Herein, a sequence of 2D MOF (TMN2O2, TM = Cr, Mn, Fe, Co, Ni, Cu, Zn) structures with 2,3,6,7,10,11-hexahydroxy­triphenylene and 2,3,6,7,10,11-triphenylene­hexamine were designed and investigated for their catalytic performance in ORR and OER by using density functional theory. Calculation results reveal that TMN2O2 (TM = Cr, Mn, Fe, Co, Ni) structures have superior thermodynamic and electrochemical stability during the electrocatalytic process. Based on oxygen and water molecule activation and free energy calculations, the CoN2O2 structure exhibits superior electrocatalytic performance for ORR and OER with low overpotential values of 0.33 and 0.30 V, respectively. The high bifunctional electrocatalytic activity for OER/ORR can be attributed to the moderate adsorption interaction of CoN2O2 structure with key intermediates. The valence orbital contribution of Co-3dz2 is critical for adjusting the interaction with the *OOH intermediate, resulting in enhancing the electrocatalytic performance for both ORR and OER

Anti-ErbB2 DVD-Ig proteins inhibit cell proliferation.

<p>(A) Calu-3, (B) MDA-MB-175 VII, and (C) N87 cells were treated with indicated dosages of DVD-Ig proteins, mAbs, or combination for 96 hrs. Cell proliferation was measured with ³H thymidine incorporation assays as described in Materials and Methods. Three independent experiments with triplicates were performed. One representative experiment is shown here. The error bars indicate standard deviation from the mean.</p

Characterization of ErbB2 binding of anti-ErbB2 DVD-Ig molecules.

<p>Characterization of ErbB2 binding of anti-ErbB2 DVD-Ig molecules.</p

Biacore analysis of ErbB2 binding affinity of anti-ErbB2 DVD-Ig molecules.

<p>Biacore analysis of ErbB2 binding affinity of anti-ErbB2 DVD-Ig molecules.</p

Density Functional Theory Study of the Adsorption and Desulfurization of Thiophene and Its Hydrogenated Derivatives on Pt(111): Implication for the Mechanism of Hydrodesulfurization over Noble Metal Catalysts

Desulfurization of thiophene and its hydrogenated derivatives on Pt(111) are studied using self-consistent periodic density functional theory (DFT), and the hydrodesulfurization network is mapped out. On Pt(111), thiophene has two types of adsorption configurations (parallel cross-bridge and partially tilted bridge-hollow), and for its hydrogenated derivates, the molecule is gradually lifted up from the surface with the addition of hydrogen atoms. In all the adsorbed thiophenic compounds, the S atom is always sp³ hybridized; the C atom in the methylene group is always sp³ hybridized, whereas it is either sp² or sp³ hybridized in the methyne group, depending on how the group interacts with the surface Pt atoms. On the basis of the thermodynamic and kinetic analysis of the elementary steps, a direct desulfurization pathway is proposed for the hydrodesulfurization of thiophene on Pt(111). In contrast to the common thought that hydrogenation toward aromatic organosulfur compounds would make desulfurization easier, the present work clearly demonstrates that hydrogenations of thiophene on Pt(111) do not reduce the energy barrier for the C–S bond cleavage