in Wiley Online Library (wileyonlinelibrary.com).Polyvinylamine (PVAm) was modified using a cross-linking agent containing carriers piperazine (PIP). Attenuated total reflectance fourier transform infrared, elemental analyzer, and X-ray diffraction were used to characterize the PIP-modified PVAm. The PVAm-PIP/polysulfone (PS) composite membrane was developed by coating PVAm-PIP mixed solutions with different mass ratios of PIP/PVAm (m PIP /m PVAm ) on the PS ultrafiltration membrane. The effects of m PIP /m PVAm (from 0.715 to 2.860) in the coating solutions and wet coating thickness on the gas performance of the PVAm-PIP/PS composite membrane were investigated. The PVAm-PIP/PS composite membrane prepared showed higher performance than other membranes reported in the literature due to the large increase of the introducing carrier concentration and low crystallinity. Moreover, the separation performance stability of the PVAm-PIP/PS composite membrane was investigated and no deterioration in the membrane permselectivity was observed. Finally, the economic evaluation of the membrane with the highest performance prepared was carried out. V V C 2012 American Institute of Chemical Engineers AIChE J, 59: 215-228, 2013 P CO2 -CO 2 partial pressure of the feed gas (MPa); P-feed gas pressure (MPa). The prepared conditions of PVAm-PIP/PS composite membrane: the m PIP / m PVAm in the coating solution is 1.430; the wet coating thickness of the PVAm-PIP/PS a composite membrane is 30 lm; the wet coating thickness of the PVAm-PIP/PS b composite membranes is 50 lm. The prepared condition of PVAm-EDA/PS composite membrane: the m EDA /m PVAm in the coating solution is 3; wet coating thickness is 50 lm.

To understand better how homogeneous catalysts comprised of two base metals can mimic precious metal catalysts, we have elucidated a complete mechanistic pathway for C−H borylation with Cu−Fe catalysts that is consistent with experimental observations as well as first-principles quantum chemistry. The catalytic cycle begins with the B−H bond of the borane inserting into the Cu−Fe bond of the catalyst, followed by bimetallic oxidative B−H activation and release of the NHCbound Cu−H group. After UV irradiation, release of CO permits the inner-sphere Fe coordination of a solvent arene molecule, which then undergoes C−H borylation via a concerted, 4-centered transition state. The resulting iron-hydride can undergo bimetallic reductive elimination with the Cu−H partner to form H 2 , closing the catalytic cycle. Analysis of fragment charges during these processes confirms that the bimetallic reaction pathways resemble oxidative addition and reductive elimination steps. Spectroscopic studies are included to probe the nature of the unsupported Cu−Fe bonds of the catalyst in solution. This extensive experimental and computational investigation provides useful insight into canonical organometallic reaction mechanisms involved in bimetallic catalysts, which are generally less well understood than their monometallic counterparts.

No abstract

No abstract

Numerous studies have examined the neural substrates of intertemporal decisionmaking, but few have systematically investigated separate neural representations of the two attributes of future rewards (i.e., the amount of the reward and the delay time). More importantly, no study has used the novel analytical method of representational connectivity analysis (RCA) to map the two dimensions' functional brain networks at the level of multivariate neural representations. This study independently manipulated the amount and delay time of rewards during an intertemporal decision task. Both univariate and multivariate pattern analyses showed that brain activity in the dorsomedial prefrontal cortex (DMPFC) and lateral frontal pole cortex (LFPC) was modulated by the amount of rewards, whereas brain activity in the DMPFC and dorsolateral prefrontal cortex (DLPFC) was modulated by the length of delay. Moreover, representational similarity analysis (RSA) revealed that even for the regions of the DMPFC that overlapped between the two dimensions, they manifested distinct neural activity patterns. In terms of individual differences, those with large delay discounting rates (k) showed greater DMPFC and LFPC activity as the amount of rewards increased but showed lower DMPFC and DLPFC activity as the delay time increased. Lastly, RCA suggested that the topological metrics (i.e., global and local

No abstract

No abstract

No abstract