Surface deoxidation mechanism during vacuum heat treatment of stainless steels AISI 304 and 446

A process of removal of surface oxides from stainless steels AISI 304 and 446 that involves reduction by residual carbon, followed by the formation and desorption of carbon monoxide, is studied by investigation of thermal desorption with quadrupole mass spectrometry (QMS) and secondary ion mass spectrometry (SIMS). Carbon monoxide desorption is studied as a function of time and temperature by QMS, and carbon diffusion due to heat treatment is studied with SIMS—twice as much carbon monoxide desorbs from AISI 304 overall and desorption sets in at 900 °C as opposed to 1100 °C for AISI 446. In samples heated to 900 °C, carbon shows surface enrichment in AISI 304 but depletion in AISI 446

Prioritisation of patients on waiting lists for hip and knee arthroplasties and cataract surgery: Instruments validation

<p>Abstract</p> <p>Background</p> <p>Prioritisation instruments were developed for patients on waiting list for hip and knee arthroplasties (AI) and cataract surgery (CI). The aim of the study was to assess their convergent and discriminant validity and inter-observer reliability.</p> <p>Methods</p> <p>Multicentre validation study which included orthopaedic surgeons and ophthalmologists from 10 hospitals. Participating doctors were asked to include all eligible patients placed in the waiting list for the procedures under study during the medical visit. Doctors assessed patients' priority through a visual analogue scale (VAS) and administered the prioritisation instrument. Information on socio-demographic data and health-related quality of life (HRQOL) (HUI3, EQ-5D, WOMAC and VF-14) was obtained through a telephone interview with patients. The correlation coefficients between the prioritisation instrument score and VAS and HRQOL were calculated. For the reliability study a self-administered questionnaire, which included hypothetic patients' scenarios, was sent via postal mail to the doctors. The priority of these scenarios was assessed through the prioritisation instrument. The intraclass correlation coefficient (ICC) between doctors was calculated.</p> <p>Results</p> <p>Correlations with VAS were strong for the AI (0.64, CI95%: 0.59–0.68) and for the CI (0.65, CI95%: 0.62–0.69), and moderate between the WOMAC and the AI (0.39, CI95%: 0.33–0.45) and the VF-14 and the CI (0.38, IC95%: 0.33–0.43). The results of the discriminant analysis were in general as expected. Inter-observer reliability was 0.79 (CI95%: 0.64–0.94) for the AI, and 0.79 (CI95%: 0.63–0.95) for the CI.</p> <p>Conclusion</p> <p>The results show acceptable validity and reliability of the prioritisation instruments in establishing priority for surgery.</p

A study of aluminium brazes using hot stage scanning electron microscopy

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Determinants of patient satisfaction with cataract surgery and length of time on the waiting list

Aims: To assess determinants of patient satisfaction with their waiting time (WT) and cataract surgery outcome. Methods: A prospective cohort of consecutive patients waiting for cataract surgery were assessed by their ophthalmologist. Satisfaction, maximum acceptable waiting time (MAWT), urgency, visual function, visual acuity (VA), and health related quality of life (EQ-5D) were assessed using mailed questionnaires before surgery and 8–10 weeks after surgery. Ordinal logistic regression was used to build explanatory models. Results: 166 patients (61.9% female, mean age 73.4 years) had a mean WT of 16 weeks. Patients whose actual WT was shorter than their MAWT had greater odds of being satisfied with their WT than those whose WT was longer (adjusted OR 3.86, 95% CI 1.38 to 10.74). Improvement in visual function (OR 3.19, 95% CI 1.78 to 5.73), and VA (OR 4.27, 95% CI 1.70 to 10.68) significantly predicted satisfaction with surgery. Models were adjusted for age and sex. Conclusion: Patient perspectives on MAWT and satisfaction with WT are important inputs to the process of determining WT standards for levels of patient priority. Patient expectation of WT may mediate satisfaction with actual WT

Vacuum brazing studies

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