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Engineering strong metal–support interactions (SMSI) is an effective strategy for tuning structures and performances of supported metal catalysts but induces poor exposure of active sites. Here, we demonstrate a strong metal–support interaction via a reverse route (SMSIR) by starting from the final morphology of SMSI (fully-encapsulated core–shell structure) to obtain the intermediate state with desirable exposure of metal sites. Using core–shell nanoparticles (NPs) as a building block, the Pd–FeOx NPs are transformed into a porous yolk–shell structure along with the formation of SMSIR upon treatment under a reductive atmosphere. The final structure, denoted as Pd–Fe3O4–H, exhibits excellent catalytic performance in semi-hydrogenation of acetylene with 100% conversion and 85.1% selectivity to ethylene at 80 °C. Detailed electron microscopic and spectroscopic experiments coupled with computational modeling demonstrate that the compelling performance stems from the SMSIR, favoring the formation of surface hydrogen on Pd instead of hydride., Strong metal–support interactions (SMSI) are effective in tuning the structures and catalytic performances of catalysts but limited by the poor exposure of active sites. Here, the authors develop a strategy to engineer SMSI via a reverse route, which is in favor of metal site exposure while embracing the SMSI.

There is evidence that impulsive decision-making is associated with errors in timing. However, there has been little attempt to identify the putative mechanism responsible for impulsive animals' timing errors. One means of manipulating impulsivity in non-human animals is providing different levels of access to conspecifics. These preclinical models have revealed that social isolation increases impulsive responding across a wide range of tasks. The goal of the present study was to determine whether social isolation modulates time perception in pigeons by inducing more variability or a bias to underestimate the passage of time in temporal judgments. A temporal bisection task was used to characterize time perception. One group of pigeons performed the bisection following social enrichment, and the remaining half of the pigeons were tested following social isolation. Results revealed pigeons in the social isolation condition categorized a temporal stimulus sample as "long" at shorter durations than pigeons in the social enrichment condition. These data highlight the mechanism(s) thought to underlie timing-based interventions aimed at reducing impulsivity in humans. Future work should consider whether impulsivity is produced by misperceptions of time or a reduced threshold for a response.

The distribution of latencies and interresponse times (IRTs) of rats was compared between two fixed-interval (FI) schedules of food reinforcement (FI 30 s and FI 90 s), and between two levels of food deprivation. Computational modeling revealed that latencies and IRTs were well described by mixture probability distributions embodying two-state Markov chains. Analysis of these models revealed that only a subset of latencies is sensitive to the periodicity of reinforcement, and prefeeding only reduces the size of this subset. The distribution of IRTs suggests that behavior in FI schedules is organized in bouts that lengthen and ramp up in frequency with proximity to reinforcement. Prefeeding slowed down the lengthening of bouts and increased the time between bouts. When concatenated, latency and IRT models adequately reproduced sigmoidal FI response functions. These findings suggest that behavior in FI schedules fluctuates in and out of schedule control; an account of such fluctuation suggests that timing and motivation are dissociable components of FI performance. These mixture-distribution models also provide novel insights on the motivational, associative, and timing processes expressed in FI performance. These processes may be obscured, however, when performance in timing tasks is analyzed in terms of mean response rates.

Functional materials for energy conversion and storage exhibit strong coupling between electrochemistry and mechanics. For example, ceramics developed as electrodes for both solid oxide fuel cells and batteries exhibit cyclic volumetric expansion upon reversible ion transport. Such chemomechanical coupling is typically far from thermodynamic equilibrium, and thus is challenging to quantify experimentally and computationally. In situ measurements and atomistic simulations are under rapid development to explore how this coupling can be used to potentially improve both device performance and durability. Here, we review the commonalities of coupling between electrochemical and mechanical states in fuel cell and battery materials, illustrating with specific cases the progress in materials processing, in situ characterization, and computational modeling and simulation. We also highlight outstanding questions and opportunities in these applications – both to better understand the limiting mechanisms within the materials and to significantly advance the durability and predictability of device performance required for renewable energy conversion and storage., United States. Dept. of Energy (Basic Energy Sciences Division of Materials Sciences and Engineering, grant DE-SC0002633), United States. Dept. of Energy (Office of Science, Graduate Fellowship Program (DOE SCGF)), United States. American Recovery and Reinvestment Act of 2009 (ORISE-ORAU, contract no. DE-AC05-06OR23100)), United States. Dept. of Energy. Division of Materials Sciences and Engineering (MIT/DMSE Salapatas Fellowship), United States. Air Force Office of Scientific Research (Presidential Early Career Award in Science and Engineering (PECASE))

When humans are asked to judge the value of a set of objects of excellent quality, they often give this set higher value than those same objects with the addition of some of lesser quality. This is an example of the affect heuristic, often referred to as the less-is-more effect. Monkeys and dogs, too, have shown this suboptimal effect. But in the present experiments, normally hungry pigeons chose optimally: a preferred food plus a less--preferred food over a more-preferred food alone. In Experiment 2, however, pigeons on a less-restricted diet showed the suboptimal less-is-more effect. Choice on control trials indicated that the effect did not result from the novelty of two food items versus one. The effect in the less-food-restricted pigeons appears to result from the devaluation of the combination of the food items by the presence of the less-preferred food item. The reversal of the effect under greater food restriction may occur because, as motivation increases, the value of the less-preferred food increases faster than the value of the more-preferred food, thus decreasing the difference in value between the two foods.

In studies of transitive inference (TI), nonhuman animals are typically trained with the following 5-term task: A+B−, B+C−, C+D−, D+E− where the letters stand for arbitrary stimuli and [+] indicates that choice is reinforced and [−] indicates that choice is not reinforced. A TI effect is found when, given the untrained test pair BD, subjects choose B. TI effects have been found in many nonhuman species. Although reinforcement history has been posited as an account of the TI effect, it has failed to account for a variety of conditions under which TI effects have been found. A more cognitive account of TI is that organisms are able to form a representation of the series (A > B > C > D > E). In support of this hypothesis, Roberts and Phelps (Psychol Sci 5:368–374, 1994) found that presentation of the pairs of stimuli in a linear arrangement facilitated TI performance by rats, whereas presentation of the pairs of stimuli in a circular arrangement did not. Using methods adapted from Roberts and Phelps, we trained pigeons on either a linear or a circular arrangement of stimuli with the 5-term task. Results indicated that on the BD test pair, pigeons trained with a circular arrangement did not differ from those trained with a linear arrangement. Furthermore, we found that memory for training pairs was variable and was highly correlated with degree of TI. The results suggest that regardless of how pigeons are able to represent the stimuli, choice was not affected by the spatial arrangement of the stimuli during training.

Chronic pain due to injury to or diseases of the nervous system, known as neuropathic pain (NP), is a common debilitating medication condition for which there are currently several symptomatically effective therapies. Therefore, early identification of NP in the primary and specialty care setting will avoid unnecessary delays in amelioration of symptoms. Given that it is associated with unique symptoms and physical exam signs, several assessment tools have been developed to aid medical practitioners in the identification of patients with NP. The majority of these tools have been developed to differentiate NP from nonNP and to quantify the severity of symptoms that define NP, and some have been used to aid in assessment of response to interventions. This focused review will describe the primary NP assessment tools that are currently available, and discuss their suitability for screening patients and for research applications. Wider use of NP assessment tools will facilitate the development of new therapies, further clarify the epidemiology of this condition, and improve the treatment of NP.