Pharmacological stimulation of infralimbic cortex after fear conditioning facilitates subsequent fear extinction.

The infralimbic (IL) division of the medial prefrontal cortex (mPFC) is a crucial site for extinction of conditioned fear memories in rodents. Recent work suggests that neuronal plasticity in the IL that occurs during (or soon after) fear conditioning enables subsequent IL-dependent extinction learning. We therefore hypothesized that pharmacological activation of the IL after fear conditioning would promote the extinction of conditioned fear. To test this hypothesis, we characterized the effects of post-conditioning infusions of the GABAA receptor antagonist, picrotoxin, into the IL on extinction of auditory conditioned freezing in male and female rats. In four experiments, we found that picrotoxin injections performed immediately, 24 hours, or 13 days after fear conditioning reduced conditioned freezing to the auditory conditioned stimulus (CS) during both extinction training and extinction retrieval; this effect was observed up to two weeks after picrotoxin infusions. Interestingly, inhibiting protein synthesis inhibition in the IL immediately after fear conditioning prevented the inhibition of freezing by picrotoxin injected 24 hours later. Our data suggest that the IL encodes an inhibitory memory during the consolidation of fear conditioning that is necessary for future fear suppression.

The effect of switchgrass loadings on feedstock solubilization and biofuel production by Clostridium thermocellum.

BACKGROUND: Efficient deconstruction and bioconversion of solids at high mass loadings is necessary to produce industrially relevant titers of biofuels from lignocellulosic biomass. To date, only a few studies have investigated the effect of solids loadings on microorganisms of interest for consolidated bioprocessing. Here, the effects that various switchgrass loadings have on Clostridium thermocellum solubilization and bioconversion are investigated. RESULTS: Clostridium thermocellum was grown for 10 days on 10, 25, or 50 g/L switchgrass or Avicel at equivalent glucan loadings. Avicel was completely consumed at all loadings, but total cellulose solubilization decreased from 63 to 37% as switchgrass loadings increased from 10 to 50 g/L. Washed, spent switchgrass could be additionally hydrolyzed and fermented in second-round fermentations suggesting that access to fermentable substrates was not the limiting factor at higher feedstock loadings. Results from fermentations on Avicel or cellobiose using culture medium supplemented with 50% spent fermentation broth demonstrated that compounds present in the supernatants from the 25 or 50 g/L switchgrass loadings were the most inhibitory to continued fermentation. CONCLUSIONS: Recalcitrance alone cannot fully account for differences in solubilization and end-product formation between switchgrass and Avicel at increased substrate loadings. Experiments aimed at separating metabolic inhibition from inhibition of hydrolysis suggest that C. thermocellum's hydrolytic machinery is more vulnerable to inhibition from switchgrass-derived compounds than its fermentative metabolism.

Pre-Implementation Study of a Nursing e-Chart: How Nurses Use Their Time.

In clinical practice, nurses perform different activities that exceed direct care of patients, and influence workload and time administration among different tasks. When implementing changes in an electronic nursing record, it is important to measure how it affects the time committed to documentation. The objective of this study was to determine the time dedicated to different activities, including those related to electronic documentation prior to implementing a redesigned nurse chart in an Electronic Health Record at the Hospital Italiano de Buenos Aires. An observational work sampling study was performed. Nursing activities observed were categorized as direct care, indirect care, support, non-patient related, and personal activities. During the study, 74 nurses were observed and 2,418 observations were made in the Intensive Care Unit (32.22%), the Intermediate Care Unit (29.57%), and the General Care Unit (38.21%). Nurses' activities included 37.40% of direct care, 41.18% of indirect care, 0.43% support tasks, 11.14% non-related to patient tasks, and 9.77% personal activities. The results allow for the estimation of the impact of a nursing e-chart on nurses' activities, workflow and patient care.