Predicting the onset of rafting of c 0 precipitates by channel deformation in a Ni superalloy

The growth or shrinkage, normal to 001, of the interfaces between the γ matrix and cuboidal γ' precipitates is examined for a Ni-base superalloy, by considering the force acting on the interfaces. The force is produced by the precipitate coherency misfit and the stress produced by plastic deformation in channels of the γ matrix. A simple expression, which directly addresses the origin of the surface force, is given. The plastic deformation within the initially active γ matrix channels exerts the force to cause rafting. The subsequent activation of other types of channels also promotes the rafting in the same direction as the first active channels, when the plastic strain of the former channels increases. These issues are also discussed in terms of analysis based on those dislocations caused by the precipitate misfit and those produced by the plastic deformation

Resonance expansions in quantum mechanics

The goal of this contribution is to discuss various resonance expansions that have been proposed in the literature.Comment: 10 pages and 1 figure; presented at the Istanbul workshop on pseudo-Hermitian Hamiltonian

Viewpoint: A response to Screening and isolation to control methicillin-resistant Staphylococcus aureus: Sense, nonsense, and evidence

Surveillance and isolation for the prevention of methicillin-resistant Staphylococcus aureus (MRSA) has become a controversial topic, one that causes heated debate and appears to be surrounded by both politics and industrial conflicts-of-interest. There have been calls from numerous authors for a movement away from rigid mandates and toward an evidence-based medicine approach. However, much of the evidence can be viewed with an entirely different interpretation. Two major studies with negative findings have had an adverse impact on recommendations regarding active detection and isolation (ADI) for MRSA. However the negative findings in these studies can be explained by shortcomings in study implementation rather than the ineffectiveness of ADI. The use of daily chlorhexidine bathing has also been proposed as an alternative to ADI in ICU settings. There are shortcomings regarding the evidence in the literature concerning the effectiveness of daily chlorhexidine bathing. One of the major concerns with universal daily chlorhexidine bathing is the development of bacterial resistance. The use of surveillance and isolation to address epidemics and common dangerous pathogens should solely depend upon surveillance and isolation\u27s ability to prevent further spread to and infection of other patients through indirect contact. At present, there is a preponderance of evidence in the literature to support continuing use of surveillance and isolation to prevent the spread of MRSA

Much Work Still to Be Done to Prevent Central Line-Associated Bloodstream Infections

Central Line Associated Bloodstream Infections (CLABSI) are all too common and often fatal events. To estimate the number of preventable CLABSIs, the authors analyzed SIR (Standardized Infection Ratio) and the number of CLABSI data from Hospital Com-pare. Several studies have suggested that an SIR of 0.35 may be achievable. If all institutions were able to perform at this level, then almost 50% of CLABSI would be prevented

Effects of Modification of Pain Protocol on Incidence of Post Operative Nausea and Vomiting.

BackgroundA Perioperative Surgical Home (PSH) care model applies a standardized multidisciplinary approach to patient care using evidence-based medicine to modify and improve protocols. Analysis of patient outcome measures, such as postoperative nausea and vomiting (PONV), allows for refinement of existing protocols to improve patient care. We aim to compare the incidence of PONV in patients who underwent primary total joint arthroplasty before and after modification of our PSH pain protocol.MethodsAll total joint replacement PSH (TJR-PSH) patients who underwent primary THA (n=149) or TKA (n=212) in the study period were included. The modified protocol added a single dose of intravenous (IV) ketorolac given in the operating room and oxycodone immediate release orally instead of IV Hydromorphone in the Post Anesthesia Care Unit (PACU). The outcomes were (1) incidence of PONV and (2) average pain score in the PACU. We also examined the effect of primary anesthetic (spinal vs. GA) on these outcomes. The groups were compared using chi-square tests of proportions.ResultsThe incidence of post-operative nausea in the PACU decreased significantly with the modified protocol (27.4% vs. 38.1%, p=0.0442). There was no difference in PONV based on choice of anesthetic or procedure. Average PACU pain scores did not differ significantly between the two protocols.ConclusionSimple modifications to TJR-PSH multimodal pain management protocol, with decrease in IV narcotic use, resulted in a lower incidence of postoperative nausea, without compromising average PACU pain scores. This report demonstrates the need for continuous monitoring of PSH pathways and implementation of revisions as needed

The Relationship Between Tort Reform and Medical Utilization

NTRODUCTION: The hidden cost of defensive medicine has been cited by policymakers as a significant driving force in the increase of our nation\u27s health-care costs. If this hypothesis is correct, one would expect that states with higher levels of tort reform will have a decrease in Medicare utilization and that medical utilization will decrease after tort reform is enacted. METHODS: State-level reimbursement data for years 1999 to 2010 (the last year available) was obtained from the Dartmouth Atlas of Health Care. Medical tort rankings for the 50 states were obtained from the Pacific Research Institute (PRI) and correlated with state medical utilization for the year 2010. In 3 states, Mississippi, Nevada, and Texas, data were available to make pretort and posttort reform comparisons. RESULTS: Data analysis between total state Medicare Reimbursements and the PRI\u27s tort rankings showed no significant observed correlation. In 6 Medicare utilization categories (total Medicare, hospital and skilled nursing facility, physician, home health agency, hospice, and durable medical equipment), a negative trend was observed when correlated with PRI tort rankings. This trend does not support the hypothesis that defensive medicine is a major driver of health-care expenditures. Tracking expenditures in the states of Texas, Nevada, and Mississippi, before and after passage of comprehensive medical tort reform gave inconsistent results and did not demonstrate substantial or meaningful total Medicare savings. In Mississippi, there was a trend of decreased expenditures after medical tort reform was passed. However, in Texas, where 80% of the analyzed enrollees resided, there was a trend of progressive increasing expenditures after tort reform was passed. CONCLUSION: The comparison of the Dartmouth Atlas Medicare Reimbursement Data with Malpractice Reform State Rankings, which are used by the PRI, did not support the hypothesis that defensive medicine is a driver of rising health-care costs. Additionally, comparing Medicare reimbursements, premedical and postmedical tort reform, we found no consistent effect on health-care expenditures. Together, these data indicate that medical tort reform seems to have little to no effect on overall Medicare cost savings

View point: gaps in the current guidelines for the prevention of Methicillin-resistant Staphylococcus aureus surgical site infections

The authors advocate the addition of two preventative strategies to the current United State’s guidelines for the prevention of surgical site infections. It is known that Staphylococcus aureus, including Methicillin-resistant Staphylococcus aureus (MRSA), carriers are at a higher risk for the development of infections and they can easily transmit the organism. The carriage rate of Staph. aureus in the general population approximates 33%. The CDC estimates the carriage rate of MRSA in the United States is approximately 2%. The first strategy is preoperative screening of surgical patients for Staph. aureus, including MRSA. This recommendation is based upon the growing literature which shows a benefit in both prevention of infections and guidance in preoperative antibiotic selection. The second is performing MRSA active surveillance screening on healthcare workers. The carriage rate of MRSA in healthcare workers approximates 5% and there are concerns of transmission of this pathogen to patients. MRSA decolonization of healthcare workers has been reported to approach a success rate of 90%. Healthcare workers colonized with dangerous pathogens, including MRSA, should be assigned to non-patient contact work areas. In addition, there needs to be implemented a safety net for both the worker’s economic security and healthcare. Finally, a reporting system for the healthcare worker acquisition and infections with dangerous pathogens needs to be implemented. These recommendations are needed because Staph. aureus including MRSA is endemic in the United States. Policies regarding endemic pathogens which are to be implemented only upon the occurrence of a facility defined “outbreak” have to be questioned, since absence of infections does not mean absence of transmission. Optimizing these policies will require further research but until then we should error on the side of patient safety

The incidence of MRSA infections in the United States: is a more comprehensive tracking system needed?

A review of epidemiological studies on the incidence of MRSA infections overtime was performed along with an analysis of data available for download from Hospital Compare (https://data.medicare.gov/data/hospital-compare). We found the estimations of the incidence of MRSA infections varied widely depending upon the type of population studied, the types of infections captured and in the definitions and terminology used to describe the results. We could not find definitive evidence that the incidence of MRSA infections in U.S. community or facilities is decreasing significantly. Of concern are recent data reported to the National Healthcare Safety Network (NHSN) on MRSA bloodstream infections which indicate that by the end of 2015 there had been little change in the average facility Standardized Infection Ratio (0.988), compared to a 2010-2011 baseline and is significantly increased compared to the previous year. This is in contradistinction to the recent Veterans Administration study which reported over an 80% reduction in MRSA infections. However, this discrepancy may be due to the inability to reconcile the baselines of the two data sets; and the observed increase may be artifactual due to aberrations in the NHSN tracking system. Our review supports the need for implementation of a comprehensive tracking and monitoring system involving all types of healthcare facilities for multi-drug resistant organisms, along with concomitant funding for both staff and infrastructure. Without such a system, determining the effectiveness of interventions such as antibiotic stewardship and chlorhexidine bathing will be hindered