INVESTIGATION INTO THE ACTIVE PASSIVE TRANSITION OF 304 STAINLESS-STEEL IN ORGANIC MEDIA CONTAINING WATER PART 2. INFLUENCE OF WATER ON THE ACTIVE DISSOLUTION AND PASSIVATION

The influence of water on the corrosion and passivation of type 304 stainless steel has been studied in deaerated ethanolic solutions containing hydrogen chloride. The potentiostatic polarisation curves show that both, critical current density for passivation and passivation potential, strongly depend on the water content of the solution. A passivation model based on the assumption of a reversible primary passivation potential explains this influence of water and allows the determination of other kinetic parameters. The propounded passivation model also explains the result that the part of “passivated” surface at the maximum current density is the same for all water contents examined. The dominating influence of the water content is shown more clearly when measurements from methanolic and propanolic solutions are concerned. The passivation potential only depends on the water content and not on the type of alcohol

In situ XANES study of the cathodic reduction behavior of the passive film on iron and artificial passive films

The objective of the present work is to compare the behavior of the passive film on iron with artificial passive films (thin sputter-deposited films of iron oxides on inert substrates). In situ XANES measurements were used to monitor both dissolution and changes in the valence state of passive films on iron during cathodic reduction in borate buffer and in NaOH. Reductive dissolution of the passive film on iron proceeds by a very similar mechanism as has been found for artificial passive films (thin, sputter-deposited films of iron oxides on inert substrates)--i.e. including a conversion step of the passive film to a lower-valent oxide. With low reduction current densities, the dissolution process does not stop when the metal is exposed but can proceed as active metal dissolution. In NaOH, no or very minor material loss takes place during reduction due to the insolubility of Fe(2+) species in the alkaline solution. By potential stepping of a thin film iron sample between reduction and oxidation range of the passive film, a conversion of the whole sample from metallic film into an oxide film can be achieved

Influence of solution chemistry on dissolution of artificial passive films

The dissolution behavior of artificial Fe, Cr, and Fe/Cr passive films (sputter-deposited Fe/Cr oxide films on inert substrates) was studied by in situ X-ray absorption near edge spectroscopy (XANES). Low pH and presence of halides (Cl{sup {minus}} and F{sup {minus}}) accelerate the dissolution due to the solubility of Fe oxides in these solutions. The presence of Fe(2+) in the oxide film strongly accelerates dissolution in acidic solution. For mixed Fe/Cr oxides, F{sup {minus}} leads to a selective dissolution of Fe oxide. Cr{sub 2}O{sub 3} is not attacked by fluoride; hence if mixed oxide films contain a sufficient amount of Cr oxide, dissolution stop is obtained, probably by surface enrichment of Cr oxide. The composition of the oxide film is also crucial for its electrochemical stability. An increased Cr{sub 2}O{sub 3} content increases the resistance against reductive dissolution, increases the resistance in aggressive solutions (low pH, halides), but decreases the resistance against oxidative dissolution

Comparison of Outcomes and Costs of Ranibizumab and Aflibercept Treatment in Real-Life

<div><p>Background</p><p>Treatment efficacy and costs of anti-VEGF drugs have not been studied in clinical routine.</p><p>Objective</p><p>To compare treatment costs and clinical outcomes of the medications when adjusting for patients’ characteristics and clinical status.</p><p>Design</p><p>Comparative study.</p><p>Setting</p><p>The largest public ophthalmologic clinic in Switzerland.</p><p>Patients</p><p>Health care claims data of patients with age-related macular degeneration, diabetic macula edema and retinal vein occlusion were matched to clinical and outcome data.</p><p>Measurements</p><p>Patients’ underlying condition, gender, age, visual acuity and retinal thickness at baseline and after completing the loading phase, the total number of injections per treatment, the visual outcome and vital status was secured.</p><p>Results</p><p>We included 315 patients (19595 claims) with a follow-up time of 1 to 99 months (mean 32.7, SD 25.8) covering the years 2006–2014. Mean age was 78 years (SD 9.3) and 200 (63.5%) were female. At baseline, the mean number of letters was 55.6 (SD 16.3) and the central retinal thickness was 400.1 μm (SD 110.1). Patients received a mean number of 15.1 injections (SD 13.7; range 1 to 85). Compared to AMD, adjusted cost per month were significantly higher (+2174.88 CHF, 95%CI: 1094.50–3255.27; p<0.001) for patients with DME, while cost per month for RVO were slightly but not significantly higher. (+284.71 CHF, 95% CI: -866.73–1436.15; p = 0.627).</p><p>Conclusions</p><p>Patients with DME are almost twice as expensive as AMD and RVO patients. Cost excess occurs with non-ophthalmologic interventions. The currently licensed anti-VEGF medications did not differ in costs, injection frequency and clinical outcomes. Linking health care claims to clinical data is a useful tool to examine routine clinical care.</p></div

Summary of cost for patient group and type of treatment.

<p>*adjusted for patients’ age, female gender, baseline visual acuity and number of injections.</p><p>Summary of cost for patient group and type of treatment.</p