The emergency surgical airway: Bridging the gap from quality outcome to performance improvement through a novel simulation based curriculum.

BACKGROUND: Emergency surgical airway is a low frequency, high risk clinical scenario. Implementing a simulation-based curriculum may bridge the gap in surgical training and address quality assurance/performance improvement (QAPI) needs. METHODS: We designed and implemented an Advanced Surgical Airway Curriculum (ASAC) modeled after proficiency-based training. General Surgery residents and student nurse anesthetists were enrolled. Evaluation consisted of cognitive tests, procedure checklists and questionnaire. RESULTS: In total, 78 participants successfully completed the ASAC. Trainees agreed that the curriculum provided the cognitive and psychomotor skills necessary to perform both an open and needle cricothyroidotomy. CONCLUSIONS: In the age of increased patient safety concerns, QAPI initiatives can serve as a driver for simulation-based training curricula, with particular focus on individualized, active learning. This may be particularly useful in high risk, low frequency scenarios in which the traditional method of "See one, Do one, Teach one," is not feasible.

Real-time shape approximation and fingerprinting of single proteins using a nanopore.

Established methods for characterizing proteins typically require physical or chemical modification steps or cannot be used to examine individual molecules in solution. Ionic current measurements through electrolyte-filled nanopores can characterize single native proteins in an aqueous environment, but currently offer only limited capabilities. Here we show that the zeptolitre sensing volume of bilayer-coated solid-state nanopores can be used to determine the approximate shape, volume, charge, rotational diffusion coefficient and dipole moment of individual proteins. To do this, we developed a theory for the quantitative understanding of modulations in ionic current that arise from the rotational dynamics of single proteins as they move through the electric field inside the nanopore. The approach allows us to measure the five parameters simultaneously, and we show that they can be used to identify, characterize and quantify proteins and protein complexes with potential implications for structural biology, proteomics, biomarker detection and routine protein analysis.

The effects of geometry and stability of solid-state nanopores on detecting single DNA molecules.

In this work we use a combination of 3D-TEM tomography, energy filtered TEM, single molecule DNA translocation experiments, and numerical modeling to show a more precise relationship between nanopore shape and ionic conductance and show that changes in geometry while in solution can account for most deviations between predicted and measured conductance. We compare the structural stability of ion beam sculpted (IBS), IBS-annealed, and TEM drilled nanopores. We demonstrate that annealing can significantly improve the stability of IBS made pores. Furthermore, the methods developed in this work can be used to predict pore conductance and current drop amplitudes of DNA translocation events for a wide variety of pore geometries. We discuss that chemical dissolution is one mechanism of the geometry change for SiNx nanopores and show that small modification in fabrication procedure can significantly increase the stability of IBS nanopores.

OMP peptide signals initiate the envelope-stress response by activating DegS protease via relief of inhibition mediated by its PDZ domain.

Transmembrane signaling between intracellular compartments is often controlled by regulated proteolysis. Escherichia coli respond to misfolded or unfolded outer-membrane porins (OMPs) in the periplasm by inducing sigma(E)-dependent transcription of stress genes in the cytoplasm. This process requires a proteolytic cascade initiated by the DegS protease, which destroys a transmembrane protein (RseA) that normally binds to and inhibits sigma(E). Here, we show that peptides ending with OMP-like C-terminal sequences bind the DegS PDZ domain, activate DegS cleavage of RseA, and induce sigma(E)-dependent transcription. These results suggest that DegS acts as a sensor of envelope stress by binding unassembled OMPs. DegS activation involves relief of inhibitory interactions between its PDZ and protease domains. Peptide binding to inhibitory PDZ domains in proteases related to DegS, including DegP/HtrA, may also regulate the degradation of specific substrates by these enzymes.

Solution structure of switch Arc, a mutant with 3(10) helices replacing a wild-type beta-ribbon.

Adjacent N11L and L12N mutations in the antiparallel beta-ribbon of Arc repressor result in dramatic changes in local structure in which each beta-strand is replaced by a right-handed helix. The full solution structure of this "switch" Arc mutant shows that irregular 3(10) helices compose the new secondary structure. This structural metamorphosis conserves the number of main-chain and side-chain to main-chain hydrogen bonds and the number of fully buried core residues. Apart from a slight widening of the interhelical angle between alpha-helices A and B and changes in side-chain conformation of a few core residues in Arc, no large-scale structural adjustments in the remainder of the protein are necessary to accommodate the ribbon-to-helix change. Nevertheless, some changes in hydrogen-exchange rates are observed, even in regions that have very similar structures in the two proteins. The surface of switch Arc is packed poorly compared to wild-type, leading to approximately 1000A(2) of additional solvent-accessible surface area, and the N termini of the 3(10) helices make unfavorable head-to-head electrostatic interactions. These structural features account for the positive m value and salt dependence of the ribbon-to-helix transition in Arc-N11L, a variant that can adopt either the mutant or wild-type structures. The tertiary fold is capped in different ways in switch and wild-type Arc, showing how stepwise evolutionary transformations can arise through small changes in amino acid sequence.