2,099 research outputs found

    Vapor Inhibitors for Corrosion Protection in Humid and Saline, Natural, and Industrial Environments

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    Corrosion is a pernicious phenomenon that appears in engineering materials, infrastructure assets, and industrial equipment exposed to the atmosphere, water, and soil. The aim of this chapter is to produce a body of knowledge on the theory and practice of corrosion inhibition so it can be used in the selection of corrosion inhibitors, to prevent and/or minimize corrosion in natural environments and industrial facilities. Corrosion inhibitors are employed in different forms such as emitters, pellets, powders, films, paints, aerosols, and aqueous and solvent solutions, depending on their chemical composition: organic or inorganic. They are impregnated on papers or plastics; closed in pouches and sachets; or added to coatings and paints to form a barrier against the attack of corrosive agents. They are employed in many industries: automotive, offshore/onshore, water, military, marine, manufacture, oil and gas, electronics, and concrete structures. A special group of corrosion inhibitors are extracted from vegetables or derived from industrial vegetable wastes, which are related to the advanced field of “Green Chemistry.” The use of vapor corrosion inhibitors (VCI) has expanded rapidly in the last decades, and is frequently mentioned in the relevant literature, in particular in professional congresses and conferences, organized by international and national corrosion associations

    Human Adipose Derived Stromal Cells Heal Critical Size Mouse Calvarial Defects

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    Human adipose-derived stromal cells (hASCs) represent a multipotent cell stromal cell type with proven capacity to differentiate along an osteogenic lineage. This suggests that they may be used to heal defects of the craniofacial or appendicular skeleton. We sought to substantiate the use of undifferentiated hASCs in the regeneration of a non-healing mouse skeletal defect..Human ASCs ossify critical sized mouse calvarial defects without the need for pre-differentiation. Recombinant differentiation factors such as BMP-2 may be used to supplement hASC mediated repair. Interestingly, ASC presence gradually dissipates from the calvarial defect site. This study supports the potential translation for ASC use in the treatment of human skeletal defects

    Does Positive Psychology Coaching Improve Trainee Well-Being? Evidence from a Longitudinal Professional Development Coaching Program in a Cohort of Pediatric Trainees

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    Introduction: Trainee burnout is common and evidence supporting the effectiveness of well-being interventions for this population is limited. We studied the effect of a longitudinal coaching program grounded in positive psychology on measures of pediatric trainee well-being. Methods: Pediatric interns and fellows (n = 67) were enrolled in a positive psychology coaching program in 2017-2019. Pediatric faculty (n = 23) underwent training and were paired with trainees outside their field of interest. Trainees were surveyed at the beginning and end of the program to assess burnout and well-being, and key skills necessary to achieve well-being. Results: Thirty-one trainees completed the baseline survey and 30 completed the end of program survey. Professional fulfillment, as measured by the Professional Fulfillment Index, improved after participating in the coaching program (Cohen’s d = 0.33, p = 0.03). On bivariate analysis, ability to cope was positively correlated with gratitude (r = 0.49, p = 0.01), PERMA (r = 0.61, p = 0.001), and self-valuation (r = 0.46, p = 0.01), and negatively correlated with intolerance of uncertainty (r = -0.46, p = 0.01). Burnout was negatively correlated with professional fulfillment (r = -0.65, p \u3c 0.001) and self-valuation (r = -0.75, p \u3c 0.001). There was no deterioration in scores for trainees who participated in the coaching program. Conclusion: Our longitudinal coaching program was associated with improvement in pediatric trainees’ professional fulfillment, identified possible drivers of well-being on bivariate analysis, and may serve as a roadmap for development of well-being curricula. Our findings suggest that well-being is not merely the absence of burnout, and maintenance of well-being during training may be just as critical as improvement

    A Flexible Inventory of Survey Items for Environmental Concepts Generated via Special Attention to Content Validity and Item Response Theory

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    We demonstrate how many important measures of belief about the environmental suffer from poor content validity and inadequate conceptual breadth (dimensionality). We used scholarship in environmental science and philosophy to propose a list of 13 environmental concepts that can be held as beliefs. After precisely articulating the concepts, we developed 85 trial survey items that emphasized content validity for each concept. The concepts’ breadth and the items’ content validity were aided by scrutiny from 17 knowledgeable critics. We administered the trial items to 449 residents of the United States and used item response theory to reduce the 85 trial items to smaller sets of items for use when survey brevity is required. The reduced sets offered good predictive ability for two environmental attitudes (R2 = 0.42 and 0.46) and indices of pro-environmental behavior (PEB, R2 = 0.23) and behavioral intention (R2 = 0.25). The predictive results were highly interpretable, owing to their robust content validity. For example, PEB was predicted by the degree to which one believes nature to be sacred, but not by the degree of one’s non-anthropocentrism. Concepts with the greatest overall predictive ability were Sacredness and Hope. Belief in non-anthropocentrism had little predictive ability for all four response variables—a claim that previously could not have been made given the widespread poverty of content validity for items representing non-anthropocentrism in existing instruments. The approach described here is especially amenable to incremental improvement, as other researchers propose more informative survey items and potentially important concepts of environmental beliefs we overlooked

    CODIFI (Concordance in Diabetic Foot Ulcer Infection) : a cross-sectional study of wound swab versus tissue sampling in infected diabetic foot ulcers in England

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    OBJECTIVE: To determine the extent of agreement and patterns of disagreement between wound swab and tissue samples in patients with an infected diabetic foot ulcer (DFU). DESIGN: Multicentre, prospective, cross-sectional study. SETTING: Primary and secondary care foot ulcer/diabetic outpatient clinics and hospital wards across England. PARTICIPANTS: Inclusion criteria: consenting patients aged ≥18 years; diabetes mellitus; suspected infected DFU. EXCLUSION CRITERIA: clinically inappropriate to take either sample. INTERVENTIONS: Wound swab obtained using Levine's technique; tissue samples collected using a sterile dermal curette or scalpel. OUTCOME MEASURES: Coprimary: reported presence, and number, of pathogens per sample; prevalence of resistance to antimicrobials among likely pathogens. Secondary: recommended change in antibiotic therapy based on blinded clinical review; adverse events; sampling costs. RESULTS: 400 consenting patients (79% male) from 25 centres.Most prevalent reported pathogens were Staphylococcus aureus (43.8%), Streptococcus (16.7%) and other aerobic Gram-positive cocci (70.6%). At least one potential pathogen was reported from 70.1% of wound swab and 86.1% of tissue samples. Pathogen results differed between sampling methods in 58% of patients, with more pathogens and fewer contaminants reported from tissue specimens.The majority of pathogens were reported significantly more frequently in tissue than wound swab samples (P<0.01), with equal disagreement for S. aureus and Pseudomonas aeruginosa. Blinded clinicians more often recommended a change in antibiotic regimen based on tissue compared with wound swab results (increase of 8.9%, 95% CI 2.65% to 15.3%). Ulcer pain and bleeding occurred more often after tissue collection versus wound swabs (pain: 9.3%, 1.3%; bleeding: 6.8%, 1.5%, respectively). CONCLUSION: Reports of tissue samples more frequently identified pathogens, and less frequently identified non-pathogens compared with wound swab samples. Blinded clinicians more often recommended changes in antibiotic therapy based on tissue compared with wound swab specimens. Further research is needed to determine the effect of the additional information provided by tissue samples. TRIAL REGISTRATION NUMBER: ISRCTN52608451

    Fishery dynamics of the California market squid (Loligo opalescens), as measured by satellite remote sensing

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    Novel data on the spatial and temporal distribution of fishing effort and population abundance are presented for the market squid fishery (Loligo opalescens) in the Southern California Bight, 1992−2000. Fishing effort was measured by the detection of boat lights by the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). Visual confirmation of fishing vessels by nocturnal aerial surveys indicated that lights detected by satellites are reliable indicators of fishing effort. Overall, fishing activity was concentrated off the following Channel Islands: Santa Rosa, Santa Cruz, Anacapa, and Santa Catalina. Fishing activity occurred at depths of 100 m or less. Landings, effort, and squid abundance (measured as landings per unit of effort, LPUE) markedly declined during the 1997−98 El Niño; landings and LPUE increased afterwards. Within a fishing season, the location of fishing activity shifted from the northern shores of Santa Rosa and Santa Cruz Islands in October, the typical starting date for squid fishing in the Bight, to the southern shores by March, the typical end of the squid season. Light detection by satellites offers a source of fine-scale spatial and temporal data on fishing effort for the market squid fishery off California, and these data can be integrated with environmental data and fishing logbook data in the development of a management plan

    A Study on the Effects of Ball Defects on the Fatigue Life in Hybrid Bearings

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    Hybrid ball bearings using silicon nitride ceramic balls with steel rings are increasingly being used in space mechanism applications due to their high wear resistance and long rolling contact fatigue life. However, qualitative and quantitative reports of the effects of ball defects that cause early fatigue failure are rare. We report on our approach to study these effects. Our strategy includes characterization of defects encountered in use, generation of similar defects in a laboratory setting, execution of full-scale bearing tests to obtain lifetimes, post-test characterization, and related finite-element modeling to understand the stress concentration of these defects. We have confirmed that at least one type of defect of appropriate size can significantly reduce fatigue life. Our method can be used to evaluate other defects as they occur or are encountered

    KELT-11b: A Highly Inflated Sub-Saturn Exoplanet Transiting the V=8 Subgiant HD 93396

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    We report the discovery of a transiting exoplanet, KELT-11b, orbiting the bright (V=8.0V=8.0) subgiant HD 93396. A global analysis of the system shows that the host star is an evolved subgiant star with Teff=5370±51T_{\rm eff} = 5370\pm51 K, M=1.4380.052+0.061MM_{*} = 1.438_{-0.052}^{+0.061} M_{\odot}, R=2.720.17+0.21RR_{*} = 2.72_{-0.17}^{+0.21} R_{\odot}, log g=3.7270.046+0.040g_*= 3.727_{-0.046}^{+0.040}, and [Fe/H]=0.180±0.075 = 0.180\pm0.075. The planet is a low-mass gas giant in a P=4.736529±0.00006P = 4.736529\pm0.00006 day orbit, with MP=0.195±0.018MJM_{P} = 0.195\pm0.018 M_J, RP=1.370.12+0.15RJR_{P}= 1.37_{-0.12}^{+0.15} R_J, ρP=0.0930.024+0.028\rho_{P} = 0.093_{-0.024}^{+0.028} g cm3^{-3}, surface gravity log gP=2.4070.086+0.080{g_{P}} = 2.407_{-0.086}^{+0.080}, and equilibrium temperature Teq=171246+51T_{eq} = 1712_{-46}^{+51} K. KELT-11 is the brightest known transiting exoplanet host in the southern hemisphere by more than a magnitude, and is the 6th brightest transit host to date. The planet is one of the most inflated planets known, with an exceptionally large atmospheric scale height (2763 km), and an associated size of the expected atmospheric transmission signal of 5.6%. These attributes make the KELT-11 system a valuable target for follow-up and atmospheric characterization, and it promises to become one of the benchmark systems for the study of inflated exoplanets.Comment: 15 pages, Submitted to AAS Journal
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