EVALUATION OF THE INTRINSIC AND EXTRINSIC FRACTURE BEHAVIOR OF IRON ALUMINIDES

Comparative finite element modeling simulations of initial intergranular fracture of two iron aluminides (FA186 and FA189) were carried out to study the intrinsic and extrinsic fracture behavior of the alloys as related to hydrogen embrittlement. The computational simulations involved sequentially-coupled stress and mass-diffusion analyses to determine the stress/strain distribution and the extent of hydrogen concentration at the crack tip region. Simulations of initial intergranular fracture of the two alloys under either air or vacuum conditions were conducted. With judicious selection of grain boundary failure strains for each alloy and assumed material degradation at hydrogen diffusion zone, the numerical results agree well with previous experimental test results. We have considered the various methods by which the thermal expansion of Fe{sub 3}Al can be modeled. As a matter of practicality, we have started with a conceptually simple continuum medium modeling, which we have used in initial calculations reported here, despite its limitations in neglecting the effects of optical phonons. This makes the results increasingly suspect for temperatures above the Debye temperature. However, the results we obtain are surprisingly good considering this important limitation. Nevertheless, we regard these results as being suspect. Therefore, in addition, we discuss a wholly new ab-initio-based method which is both more accurate (preserves the ab-initio-generated information) and computationally more efficient. This method can directly transform the all-electron ab initio electronic structure results of the full-potential LMTO electronic structure behavior, computationally provided in reciprocal space, to the real space representation needed for the thermal expansion modeling. An increase of computational speed, use of larger supercells, and more efficient calculations, can all be achieved by using real space (tight-binding (TB)) calculations. The TB parameters are obtained from direct Fourier transform of the matrix elements in momentum space for a specific structure and specific lattice constant. The parameters that may change significantly are the onsite parameters, which depend on the onsite electron density. To make a usable look-up table, good for variable lattice constant in the same structure, one can perform several runs with different lattice constants and obtain a fitting function of the onsite parameter as a function of lattice constant, for each orbital in each atom. We are at present implementing this method for initial application to Fe{sub 3}Al before proceeding to a study of molybdenum silicide systems

Correction: A Feasible and Efficacious Mobile-Phone Based Lifestyle Intervention for Filipino Americans with Type 2 Diabetes: Randomized Controlled Trial.

[This corrects the article DOI: 10.2196/diabetes.8156.]

Introducing standardized “readbacks” to improve patient safety in surgery: a prospective survey in 92 providers at a public safety-net hospital

Background: Communication breakdowns represent the main root cause of preventable complications which lead to harm to surgical patients. Standardized readbacks have been successfully implemented as a main pillar of professional aviation safety for decades, to ensure a safe closed-loop communication between air traffic control and individual pilots. The present study was designed to determine the perception of staff in perioperative services regarding the role of standardized readbacks for improving patient safety in surgery at a single public safety-net hospital and level 1 trauma center. Methods: A 12-item questionnaire was sent to 180 providers in perioperative services at Denver Health Medical Center. The survey was designed to determine the individual participants’ perception of (1) appropriateness of current readback processes; (2) willingness to attend a future training module on this topic; (3) specific scenarios in which readbacks may be effective; and (4) perceived major barriers to the implementation of standardized readbacks. Survey results were compared between departments (surgery versus anesthesia) and between specific staff roles (attending or midlevel provider, resident physician, nursing staff), using non-parametric tests. Results: The response rate to the survey was 50.1 % (n = 92). Respondents overwhelmingly recognized the role of readbacks in reducing communication errors and improving patient safety. There was a strong agreement among respondents to support participation in a readbacks training program. There was no difference in the responses between the surgery and anesthesia departments. There was a statistically significant difference in the healthcare providers willingness to attend a short training module on readbacks (p < 0.001). Resident physicians were less likely to endorse the importance of readbacks in reducing communication errors (p = 0.01) and less willing to attend a short training module on readbacks (p < 0.001), as compared to staff providers and nursing staff. The main challenge for respondents, which emanated from their responses, appeared to relate to determining the ideal scenarios in which readbacks may be most appropriately used. Overall, respondents strongly felt that readbacks had an important role in patient handoffs, patient orders regarding critical results, counting and verifying surgical instruments, and delegating multiple perioperative tasks. Conclusion: The majority of all respondents appear to perceive standardized readbacks as an effective tool for reducing and/or preventing adverse events in the care of surgical patients, derived from a breakdown in communication among perioperative caregivers. Further work needs to be done to define the exact clinical scenarios in which readbacks may be most efficiently implemented, including the definition of a uniform set of scripted quotes and phrases, which should likely be standardized in concert with the aviation safety model

Low intensity shockwave treatment modulates macrophage functions beneficial to healing chronic wounds

Acknowledgments: We acknowledge the University of Aberdeen Microscopy and Histology Facility and the qPCR facility for use of facilities and advice. We acknowledge Ehab Husain for scoring the patient wound biopsies. Funding: This research was funded by NHS Grampian Endowments, grant number 17/004 and by personal funding from JSH.Peer reviewedPublisher PD