85 research outputs found
Sonochemical route to create superconducting and superparamagnetic nanocomposites
The purpose of this study is to demonstrate the capability of a single process, heterogenous sonochemistry, as a tool to produce two very different nanocomposites with tunable properties: a superconductor, MgB2 with nano-inclusions, and iron/iron oxide (Fe/Fe2O3) in an alumina (Al2O3) matrix. By modifying the sonochemical parameters, one is able to tune the magnetic properties and enhance the superconducting properties of MgB2 and the superparamagnetic (SPM) properties of the Fe/Al2O3 system. This tuning is done through the ability of sonochemical irradiation, â)))â or the exposure to high intensity ultrasound (HIU), to produce extreme environments where chemical and physical processes can occur due to acoustic cavitation. ))) has been shown to reduce particle size, increase reactivity, act as a catalyst, and improve powder homogeneity. These are the effects of ))) which are exploited in this study.
For the MgB2 study, B powder (both with and without dopants/inclusions) is exposed to HIU in a decane solution before reaction with Mg to form MgB2 nanocomposites. MgB2 is produced by encapsulation of stoichiometric amounts of B and Mg in a Ta pouch, which is then reacted and pressed using hot isostatic press (HIP). The result is a dense MgB2 pellet that is then cut, polished, and measured using a SQUID MPMS magnetometer. Critical current, Jc, values are calculated using the Bean critical state and compared at 25K and 30K. Samples, post-))), show an increase in grain connectivity, as seen by SEM, leading to an enhancement of Jc.
The SPM study utilized ))) to create SPM nanocomposites through the irradiation with HIU of the carrier matrix material, Al2O3 in the presence of a volatile organometallic precursor, Fe(CO)5. ))) results in nanosized Fe and Fe2O3 being uniformly dispersed throughout the Al2O3 matrix. Magnetic properties of these materials are measured using the SQUID MPMS magnetometer and the nanosized Fe and Fe2O3 can be seen in SEM images. Analysis of the data shows a SPM component and a general trend of the data with the adjustment of slurry loading, V% of sample to medium, and mass percentage, M% of Fe to Fe+Al2O3. The trends suggest that an increase in M% results in an increased number of SPM particles, but the V% has a optimized value where the magnetization peaks, corresponding to a peak in the moment per SPM particle
Effects of High Intensity Ultrasound on BSCCO-2212 Superconductor
Slurries of powdered Bi2Sr2CaCu2O8+x superconductor in low volatility alkanes
were treated with intense ultrasound. Significant enhancements of magnetic
irreversibility as well as transport critical current are reported. The effects
are dependent on the concentration of the slurry and are optimal for 1.5% wt.
slurry loading. Electron microscopy shows that ultrasonic treatment leads to a
change in grain morphology and intergrain welding. The observed enhancement of
superconducting properties is consistent with the limitations in critical
currents in BSCCO superconductor being due to intergrain coupling rather than
intragrain pinning strength.Comment: 3 page
Initial Validation and Findings From the Willing/Ready Subscale of the Church Addiction Response Scale
Addiction has been a global health crisis over recent decades and worsened substantially during COVID-19 lockdowns. We report on the development, validation, and findings from an instrument developed to assess the readiness of churches in the Appalachian Highlands to address addiction. The Church Addiction Response Scale (CARS) is a 41-item, three section measure assessing âWhat are your views about addiction?â (14 items), âWhat are your views about interacting with people who are addicted to drugs?â (11 items), and âWhat do you think the churchâs role is in addressing addiction?â (16 items). The CARS was found to be unidimensional with strong internal consistency and initial evidence of construct validity was positive. Most respondents reported willingness to assist people living with addiction, but many reported that they felt underprepared, thus were not ready. Areas of preparation were largely those that could be addressed through training, such as understanding the physiology and psychology of addiction, available treatment options, and how to avoid doing harm. Thus, with adequate training, the likelihood of equipping a church-based workforce to provide support for people living with addiction seems attainable
Cataract research using electronic health records
<p>Abstract</p> <p>Background</p> <p>The eMERGE (electronic MEdical Records and Genomics) network, funded by the National Human Genome Research Institute, is a national consortium formed to develop, disseminate, and apply approaches to research that combine DNA biorepositories with electronic health record (EHR) systems for large-scale, high-throughput genetic research. Marshfield Clinic is one of five sites in the eMERGE network and primarily studied: 1) age-related cataract and 2) HDL-cholesterol levels. The purpose of this paper is to describe the approach to electronic evaluation of the epidemiology of cataract using the EHR for a large biobank and to assess previously identified epidemiologic risk factors in cases identified by electronic algorithms.</p> <p>Methods</p> <p>Electronic algorithms were used to select individuals with cataracts in the Personalized Medicine Research Project database. These were analyzed for cataract prevalence, age at cataract, and previously identified risk factors.</p> <p>Results</p> <p>Cataract diagnoses and surgeries, though not type of cataract, were successfully identified using electronic algorithms. Age specific prevalence of both cataract (22% compared to 17.2%) and cataract surgery (11% compared to 5.1%) were higher when compared to the Eye Diseases Prevalence Research Group. The risk factors of age, gender, diabetes, and steroid use were confirmed.</p> <p>Conclusions</p> <p>Using electronic health records can be a viable and efficient tool to identify cataracts for research. However, using retrospective data from this source can be confounded by historical limits on data availability, differences in the utilization of healthcare, and changes in exposures over time.</p
Intravenous antibiotics for pulmonary exacerbations in people with cystic fibrosis
BACKGROUND: Cystic fibrosis is a multi-system disease characterised by the production of thick secretions causing recurrent pulmonary infection, often with unusual bacteria. Intravenous antibiotics are commonly used in the treatment of acute deteriorations in symptoms (pulmonary exacerbations); however, recently the assumption that exacerbations are due to increases in bacterial burden has been questioned. OBJECTIVES: To establish if intravenous antibiotics for the treatment of pulmonary exacerbations in people with cystic fibrosis improve short- and long-term clinical outcomes. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews and ongoing trials registers.Date of last search of Cochrane trials register: 27 July 2015. SELECTION CRITERIA: Randomised controlled trials and the first treatment cycle of cross-over studies comparing intravenous antibiotics (given alone or in an antibiotic combination) with placebo, inhaled or oral antibiotics for people with cystic fibrosis experiencing a pulmonary exacerbation. DATA COLLECTION AND ANALYSIS: The authors assessed studies for eligibility and risk of bias and extracted data. MAIN RESULTS: We included 40 studies involving 1717 participants. The quality of the included studies was largely poor and, with a few exceptions, these comprised of mainly small, inadequately reported studies.When comparing treatment with a single antibiotic to a combined antibiotic regimen, those participants receiving a combination of antibiotics experienced a greater improvement in lung function when considered as a whole group across a number of different measurements of lung function, but with very low quality evidence. When limited to the four placebo-controlled studies (n = 214), no difference was observed, again with very low quality evidence. With regard to the review's remaining primary outcomes, there was no effect upon time to next exacerbation and no studies in any comparison reported on quality of life. There were no effects on the secondary outcomes weight or adverse effects. When comparing specific antibiotic combinations there were no significant differences between groups on any measure. In the comparisons between intravenous and nebulised antibiotic or oral antibiotic (low quality evidence), there were no significant differences between groups on any measure. No studies in any comparison reported on quality of life. AUTHORS' CONCLUSIONS: The quality of evidence comparing intravenous antibiotics with placebo is poor. No specific antibiotic combination can be considered to be superior to any other, and neither is there evidence showing that the intravenous route is superior to the inhaled or oral routes. There remains a need to understand host-bacteria interactions and in particular to understand why many people fail to fully respond to treatment
Subsequent Surgery After Revision Anterior Cruciate Ligament Reconstruction: Rates and Risk Factors From a Multicenter Cohort
BackgroundWhile revision anterior cruciate ligament reconstruction (ACLR) can be performed to restore knee stability and improve patient activity levels, outcomes after this surgery are reported to be inferior to those after primary ACLR. Further reoperations after revision ACLR can have an even more profound effect on patient satisfaction and outcomes. However, there is a current lack of information regarding the rate and risk factors for subsequent surgery after revision ACLR.PurposeTo report the rate of reoperations, procedures performed, and risk factors for a reoperation 2 years after revision ACLR.Study designCase-control study; Level of evidence, 3.MethodsA total of 1205 patients who underwent revision ACLR were enrolled in the Multicenter ACL Revision Study (MARS) between 2006 and 2011, composing the prospective cohort. Two-year questionnaire follow-up was obtained for 989 patients (82%), while telephone follow-up was obtained for 1112 patients (92%). If a patient reported having undergone subsequent surgery, operative reports detailing the subsequent procedure(s) were obtained and categorized. Multivariate regression analysis was performed to determine independent risk factors for a reoperation.ResultsOf the 1112 patients included in the analysis, 122 patients (11%) underwent a total of 172 subsequent procedures on the ipsilateral knee at 2-year follow-up. Of the reoperations, 27% were meniscal procedures (69% meniscectomy, 26% repair), 19% were subsequent revision ACLR, 17% were cartilage procedures (61% chondroplasty, 17% microfracture, 13% mosaicplasty), 11% were hardware removal, and 9% were procedures for arthrofibrosis. Multivariate analysis revealed that patients aged <20 years had twice the odds of patients aged 20 to 29 years to undergo a reoperation. The use of an allograft at the time of revision ACLR (odds ratio [OR], 1.79; P = .007) was a significant predictor for reoperations at 2 years, while staged revision (bone grafting of tunnels before revision ACLR) (OR, 1.93; P = .052) did not reach significance. Patients with grade 4 cartilage damage seen during revision ACLR were 78% less likely to undergo subsequent operations within 2 years. Sex, body mass index, smoking history, Marx activity score, technique for femoral tunnel placement, and meniscal tearing or meniscal treatment at the time of revision ACLR showed no significant effect on the reoperation rate.ConclusionThere was a significant reoperation rate after revision ACLR at 2 years (11%), with meniscal procedures most commonly involved. Independent risk factors for subsequent surgery on the ipsilateral knee included age <20 years and the use of allograft tissue at the time of revision ACLR
Multirater Agreement of the Causes of Anterior Cruciate Ligament Reconstruction Failure
BackgroundAnterior cruciate ligament (ACL) reconstruction failure occurs in up to 10% of cases. Technical errors are considered the most common cause of graft failure despite the absence of validated studies. Limited data are available regarding the agreement among orthopaedic surgeons regarding the causes of primary ACL reconstruction failure and accuracy of graft tunnel placement.HypothesisExperienced knee surgeons have a high level of interobserver reliability in the agreement about the causes of primary ACL reconstruction failure, anatomic graft characteristics, and tunnel placement.Study designCohort study (diagnosis); Level of evidence, 3.MethodsTwenty cases of revision ACL reconstruction were randomly selected from the Multicenter ACL Revision Study (MARS) database. Each case included the patient's history, standardized radiographs, and a concise 30-second arthroscopic video taken at the time of revision demonstrating the graft remnant and location of the tunnel apertures. All 20 cases were reviewed by 10 MARS surgeons not involved with the primary surgery. Each surgeon completed a 2-part questionnaire dealing with each surgeon's training and practice, as well as the placement of the femoral and tibial tunnels, condition of the primary graft, and the surgeon's opinion as to the causes of graft failure. Interrater agreement was determined for each question with the kappa coefficient and the prevalence-adjusted, bias-adjusted kappa (PABAK).ResultsThe 10 reviewers have been in practice an average of 14 years and have performed at least 25 ACL reconstructions per year, and 9 were fellowship trained in sports medicine. There was wide variability in agreement among knee experts as to the specific causes of ACL graft failure. When participants were specifically asked about technical error as the cause for failure, interobserver agreement was only slight (PABAK = 0.26). There was fair overall agreement on ideal femoral tunnel placement (PABAK = 0.55) but only slight agreement on whether a femoral tunnel was too anterior (PABAK = 0.24) and fair agreement on whether it was too vertical (PABAK = 0.46). There was poor overall agreement for ideal tibial tunnel placement (PABAK = 0.17).ConclusionThis study suggests that more objective criteria are needed to accurately determine the causes of primary ACL graft failure as well as the ideal femoral and tibial tunnel placement in patients undergoing revision ACL reconstruction
The detrimental impact of extracellular bacterial proteases on wound healing
In addition to clinical signs of infection (e.g. inflammation, purulence and pain), a microbial count of â„105 colonyâforming units/g has historically been used to define wound infection. However, it is increasingly recognised that, rather than a high bioburden level alone being detrimental to wound healing, it is the virulence of the invading microorganism and the host's immune status that can affect clinical outcomes. Bacteria, such as Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis, have developed a range of virulence factors to help them overcome host defences and proliferate within the underlying soft tissue. More specifically, bacterial proteases are one such virulence factor that has been implicated in promoting the invasion and destruction of the host tissue. Because of the complexities of microorganisms, the proteases can negatively impact the wound environment, leading to delayed wound healing. The aim of the present paper is to describe various extracellular bacterial proteases; review the impact they have on the wound environment, the host immune response and biofilms; and discuss potential wound management strategies against them. The evidence discussed suggests that proteases may play a profound role in wound infections, contribute to the development of an inflammatory response and impede wound healing
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