Personality describes persistent human behavioral responses to broad classes of environmental stimuli. Investigating how personality traits are reflected in the brain's functional architecture is challenging, in part due to the difficulty of designing appropriate task probes. Resting-state functional connectivity (RSFC) can detect intrinsic activation patterns without relying on any specific task. Here we use RSFC to investigate the neural correlates of the five-factor personality domains. Based on seed regions placed within two cognitive and affective ‘hubs’ in the brain—the anterior cingulate and precuneus—each domain of personality predicted RSFC with a unique pattern of brain regions. These patterns corresponded with functional subdivisions responsible for cognitive and affective processing such as motivation, empathy and future-oriented thinking. Neuroticism and Extraversion, the two most widely studied of the five constructs, predicted connectivity between seed regions and the dorsomedial prefrontal cortex and lateral paralimbic regions, respectively. These areas are associated with emotional regulation, self-evaluation and reward, consistent with the trait qualities. Personality traits were mostly associated with functional connections that were inconsistently present across participants. This suggests that although a fundamental, core functional architecture is preserved across individuals, variable connections outside of that core encompass the inter-individual differences in personality that motivate diverse responses.
A pentamethylcyclopentadienyl
(Cp*) iridium water-oxidation precatalyst
was modified to include a silatrane functional group for covalent
attachment to metal oxide semiconductor surfaces. The heterogenized
catalyst was found to perform electrochemically driven water oxidation
at an overpotential of 462 mV with a turnover number of 304 and turnover
frequency of 0.035 s–1 in a 0.1 M KNO3 electrolyte at pH 5.8. Computational modeling of the experimental
IR spectra suggests that the catalyst retains its Cp* group during
the first hour of catalysis and likely remains monomeric.
A switchable mild electrocatalytic protocol to transform glycerol, a byproduct of biodiesel production, into either lactic or glyceric acid is reported.
We describe a systematic method for the preparation and spectroscopic characterization of a CO2 molecule coordinated to an activated bisphenoidal nickel(I) compound containing a tetraazamacrocyclic ligand in the gas phase. The resulting complex was then structurally characterized by using mass-selected vibrational predissociation spectroscopy. The results indicate that a highly distorted CO2 molecule is bound to the metal center in an η(2)-C,O coordination mode, thus establishing an efficient and rational method for the preparation of metal-activated CO2 for further studies using ion chemistry techniques.
We show that a broad range of aryl iodides are efficiently coupled with secondary phosphine oxides using 1 mol % of a catalyst formed in situ from tris(dibenzylideneacetone)dipalladium and Xantphos (1). Scalemic (S)-methylphenylphosphine oxide [(S)-2e] is shown to undergo arylation without detectable stereoerosion. The application of this method to the synthesis of novel P-chiral phosphines and PCP ligands is demonstrated.
The
conformational preferences of 28 sterically and electronically
diverse N-aryl amides were determined using density
functional theory (DFT), using the B3LYP functional and 6-31G(d) basis
set. For each compound, both the cis and trans conformers were optimized,
and the difference in ground state energy calculated. For six of the
compounds, the potential energy surface was determined as a function
of rotation about the N-aryl bond (by 5° increments) for both
cis and trans conformers. A natural bond orbital (NBO) deletion strategy
was also employed to determine the extent of the contribution of conjugation
to the energies of each of the conformers. By comparing these computational
results with previously reported experimental data, an explanation
for the divergent conformational preferences of 2° N-aryl amides and 3° N-alkyl-N-aryl amides was formulated. This explanation accounts for the observed
relationships of both steric and electronic factors determining the
geometry of the optimum conformation, and the magnitude of the energetic
difference between cis and trans conformers: except under the most
extreme scenarios, 2° amides maintain a trans conformation, and
the N-bound arene lies in the same plane as the amide
unless it has ortho substituents; for 3° N-alkyl-N-aryl amides in which the alkyl and aryl substituents are
connected in a small ring, trans conformations are also favored, for
most cases other than formamides, and the arene and amide remain in
conjugation; and for 3° N-alkyl-N-aryl amides in which the alkyl and aryl substituents are not connected
in a small ring, allylic strain between the two N-bound substituents forces the aryl substituent to rotate out of the
plane of the amide, and the trans conformation is destabilized with
respect to the cis conformation due to repulsion between the π
system of the arene and the lone pairs on the oxygen atom of the carbonyl.
The cis conformation is increasingly more stable than the trans conformation
as electron density is increased on the arene because the more electron-rich
arenes adopt a more orthogonal arrangement, increasing the interaction
with the carbonyl oxygen, while simultaneously increasing the magnitude
of the repulsion due to the increased electron density in the π
system. The trans conformation is favored for 2° amides even
when the arene is orthogonal to the amide, in nearly all cases, because
the C–N–C bond angle can expend at the expense of the
C–N–H bond angles, while this is not favorable for 3°
amides.
We report a heterogeneous cobalt−phosphinebased water oxidation catalyst that was produced by thermal synthesis, and can be easily and rapidly deposited onto a variety of substrates from a suspension. Application of the catalyst dramatically improved the oxygen evolution efficiency and corrosion-resistance of stainless steel, nickel and copper anodes in alkaline media. More than 20 g of catalyst was prepared in a single batch, and it was shown to be effective at surface loadings as low as 20 μg/cm 2 . The catalyst was investigated in three different systems: (1) An alkaline electrolyzer with stainless steel electrodes activated with the catalyst supported 120−200% of the current density of an unactivated but otherwise identical electrolyzer, over a range of applied potentials, and maintained this improved efficiency throughout 1495 h of continuous use in 1 M NaOH. (2) Copper anodes were activated and protected from corrosion in dilute sodium hydroxide for 8 h of electrolysis, before a steady decrease in performance over the next 48 h. (3) Activation of nickel anodes with the catalyst reduced the required overpotential by 90−130 mV at current densities between 7.5 and 15 mA/cm 2 , thereby increasing the cell efficiency of water splitting as well as zinc deposition from alkaline zincate electrolytes. The cell efficiency for zinc deposition at a current density of 12.5 mA/cm 2 was improved from 68.0% with a nickel anode to 72.0% with 50 μg/cm 2 catalyst on the nickel anode.
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