Ta-ITO Coated Titanium Bipolar Plates for Proton Exchange Membrane Water Electrolyzers

A novel bi-layer coating composed of a tantalum base layer with an Indium Tin Oxide (ITO) top layer was applied to titanium substrates. Samples were polarized ex situ in a parameter study, where the pH, potential and temperature of the electrolyte was altered, as well as the polarization duration. The Interfacial Contact Resistance (ICR) after polarization showed an increase with time for the first 24 h, then stabilized at approx. 30 mΩ cm2. Minor variations were seen in the ICR after polarization at 1.4 VRHE and 2.0 VRHE, but after polarization at 2.5 VRHE and 2.6 VRHE, the ICR increased to 102 mΩ cm2 and 503 mΩ cm2, respectively. X-ray photoelectron spectroscopy (XPS) analysis revealed that the oxygen to metal ratio on the Tantalum- Indium Tin Oxide (Ta-ITO) coated sample surfaces increased with increasing polarization potential. The surfaces of the samples polarized at 2.5 VRHE and 2.6 VRHE showed lower concentrations of oxygen vacancies, an increase in hydroxides and a decrease in metallic character compared to the non-coated and baseline samples. ITO proved to be a promising candidate for use as coating on BiPolar Plates (BPPs) in Proton Exchange Membrane Water Electrolyzers (PEMWEs).publishedVersio

The association between disease activity and NT-proBNP in 238 patients with rheumatoid arthritis: a 10-year longitudinal study

Introduction Disease activity in patients with rheumatoid arthritis (RA) is associated with increased cardiovascular morbidity and mortality, of which N-terminal pro-brain natriuretic peptide (NT-proBNP) is a predictor. Our objective was to examine the cross-sectional and longitudinal associations between markers of inflammation, measures of RA disease activity, medication used in the treatment of RA, and NT-proBNP levels (dependent variable). Methods Two hundred thirty-eight patients with RA of less than 4 years in duration were followed longitudinally with three comprehensive assessments of clinical and radiographic data over a 10-year period. Serum samples were frozen and later batch-analyzed for NT-proBNP levels and other biomarkers. Bivariate, multivariate, and repeated analyses were performed. Results C-reactive protein (CRP) levels at baseline were cross-sectionally associated with NT-proBNP levels after adjustment for age and gender (r 2 adjusted = 0.23; P < 0.05). At the 10-year follow-up, risk factors for cardiovascular disease were recorded. Duration of RA and CRP levels were independently associated with NT-proBNP in the final model that was adjusted for gender, age, and creatinine levels (r 2 adjusted = 0.38; P < 0.001). In the longitudinal analyses, which adjusted for age, gender, and time of follow-up, we found that repeated measures of CRP predicted NT-proBNP levels (P < 0.001). Conclusion CRP levels are linearly associated with levels of NT-proBNP in cross-sectional and longitudinal analyses of patients with RA. The independent associations of NT-proBNP levels and markers of disease activity with clinical cardiovascular endpoints need to be further investigated

Antibodies to cyclic citrullinated protein and erythrocyte sedimentation rate predict hand bone loss in patients with rheumatoid arthritis of short duration: a longitudinal study

Introduction Radiographic progression in rheumatoid arthritis (RA) has in several studies been shown to be predicted by serological markers widely used in daily clinical practice. The objective of this longitudinal study was to examine if these serological markers also predict hand bone mineral density (BMD) loss in patients with RA of short disease duration. Methods 163 patients with RA of short disease duration (2.4 years) were included and followed longitudinally. Antibodies to cyclic citrullinated protein (anti-CCP), rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were analysed from baseline blood-samples. Hand BMD was measured by digital X-ray radiogrammetry (DXR) based on hand and wrist radiographs obtained at baseline and 1, 2 and 5-year follow-up. Results During the study period, DXR-BMD decreased by median (inter quartile range) 1.7% (4.1 to 0.4), 2.8% (5.3 to 0.9) and 5.6% (11.7 to 2.3) after 1, 2 and 5 years, respectively. Elevated baseline anti-CCP, RF, ESR and CRP levels were in univariate linear regression analyses consistently associated with DXR-BMD change at all time-points. Anti-CCP and ESR were independently associated with hand DXR-BMD in multivariate linear regression analyses. Elevated anti-CCP levels were consistent and independent predictors of loss in cortical hand bone during the study period, with the odds ratios (95% confidence interval) 2.2 (1.0 to 4.5), 2.6 (1.1 to 6.2) and 4.9 (1.4 to 16.7) for the 1, 2, and 5-year follow-up periods, respectively. Conclusions Anti-CCP and ESR were found to be independent predictors of early localised BMD loss. This finding adds to the understanding of anti-CCP and ESR as important predictors of bone involvement in RA

Exploring Tai Chi in rheumatoid arthritis: a quantitative and qualitative study

<p>Abstract</p> <p>Background</p> <p>Rheumatoid arthritis (RA) is a chronic, inflammatory and systemic disease which affects the musculoskeletal system. Exercise programmes are reported to improve physical functioning in patients with RA. Tai Chi is a traditional Chinese martial art which combines slow and gentle movements with mental focus. The purpose of this study was to study in which way Tai Chi group exercise impacted on disease activity, physical function, health status and experience in RA patients, applying quantitative and qualitative methods.</p> <p>Methods</p> <p>Fifteen patients with RA (13 females, age 33-70 years) were recruited from a rheumatology department into a single group study. The patients were instructed in Tai Chi exercise twice weekly for 12 weeks. Assessments at baseline, 12 weeks, and 12 weeks follow-up were performed with a wide range of measures, including disease activity, self-reported health status, physical performance tests (Walking in Figure of Eight, Timed-Stands Test, and Shoulder Movement Impairment Scale). Qualitative data were obtained from a focus group interview conducted after completed intervention with taping and verbatim transcription. Review of the transcripts identified themes important to patients practicing Tai Chi.</p> <p>Results</p> <p>Within the group, Tai Chi practice lead to improved lower-limb muscle function at the end of intervention and at 12 weeks follow-up. Qualitative analyses showed that patients experienced improved physical condition, confidence in moving, balance and less pain during exercise and in daily life. Other experience included stress reduction, increased body awareness, confidence in moving and indicated that Tai Chi was a feasible exercise modality in RA.</p> <p>Conclusions</p> <p>Improved muscle function in lower limbs was also reflected when patient experiences with Tai Chi were studied in depth in this explorative study. The combination of qualitative and quantitative research methods shows that Tai Chi has beneficial effects on health not related to disease activity and standardised health status assessment, and may contribute to an understanding of how Tai Chi exerts its effects.</p> <p>Trial registration</p> <p>NCT00522054</p

Measuring In Situ Interfacial Contact Resistance in a Proton Exchange Membrane Fuel Cell

Interfacial contact resistance (ICR) is one of the remaining hurdles for successful implementation of stainless steel bipolar plates in PEM fuel cells. We have developed a reliable method, using thin gold wires, to measure the interfacial contact resistance between the bipolar plate material and the porous transport layer during fuel cell operation. The ICR values were found to be in the same range as the ICR values measured ex situ after fuel cell operation. Local ex situ ICR measurements on tested plates indicate uneven current distribution during fuel cell operation. Consequently, an average between three measuring points was used for the in situ measurements, which enabled consistent monitoring of the ICR development alongside fuel cell performance. For almost all of the tests, the largest ICR changes took place within the first two hours of operation, showing the importance of early ICR measurements. Non-coated stainless steel and titanium-coated steel BPPs experienced a higher ICR compared to the gold coated stainless steel.publishedVersio

Personal non-commercial use only

ABSTRACT. Objective. To calculate the average age-and sex-specific annual incidence of rheumatoid arthritis (RA) linked to clinically important levels of health status after 10 years, and to study time trends in 10-year disease status during a 6-year period. Methods. Patients between 20 and 79 years of age with onset of RA from 1988 to 1993 (n = 550) were asked to participate in a 10-year followup examination. Two hundred sixteen patients in different age and sex groups from 6 different annual cohorts met during the period 1998-2003. Study variables included demographic variables, medication, swollen, tender and deformed joint counts, erythrocyte sedimentation rate, Disease Activity Score (DAS28), Health Assessment Questionnaire, and pain and fatigue on a 100 mm visual analog scale and Arthritis Impact Measurement Scale 2. Age-and sex-specific incidences of RA exceeding clinically important levels 10 years after disease onset were calculated using the Poisson distribution with 95% confidence intervals. Analysis of covariance and logistic regression were used to test the influence of time on 10-year DAS28 and presence of deformed joints. Results. The average annual incidence of cases exceeding clinically important levels in disease activity and health status 10 years after disease onset increased with higher age and was highest among women. There was a tendency to lower disease activity 10 years after disease onset in the latest cohorts compared to the earliest cohorts. Conclusion. These results from population-based RA incidence cohorts provide important information to healthcare planners and support findings of secular decline in disease burden. (First Release Nov 15 2007; J Rheumatol 2008;35:54-60

Pain and psychological health status over a 10‐year period in patients with recent onset rheumatoid arthritis

OBJECTIVE: To examine rheumatoid arthritis (RA) with short disease duration over 10 years, and to identify factors that are associated with the course of pain, depression and anxiety. METHODS: A cohort of 238 patients with RA (age 20-70 years, mean disease duration 2.3 years, 68% rheumatoid factor positive) was followed with assessments at baseline and after 1, 2, 5 and 10 years. Self-reported health status was assessed by pain on a 100 mm visual analogue scale, the Arthritis Impact Measurement Scales (AIMS), the 28-item version of General Health Questionnaires, and the Health Assessment Questionnaire. We also examined the erythrocyte sedimentation ratio, grip strength (kg) and radiographic progression of the hands (van der Heijde modified Sharp score). Repeated measures analyses of variance were used to explore the effect of time on measures of outcome among completers, whereas repeated measures analyses using a mixed model were applied to identify factors that were longitudinally associated with pain, depression and anxiety. RESULTS: At the various assessment points 30% had a visual analogue scale pain score of > or =40 mm, 5-13% had an AIMS depression score of > or =4.0 and 20-30% had an AIMS anxiety score of > or =4.0. The perceived level of pain was explained longitudinally by anxiety, disease activity, physical function and female gender, depression by high disease activity and anxiety, whereas anxiety was explained by low disease activity and depression. CONCLUSION: More patients had increased levels of anxiety (20-30%) than increased levels of depression (5-13%). Several factors, including anxiety, but not depression, were associated with the course of pain

Materials for Proton Exchange Membrane water electrolyzer bipolar plates

Titanium based BiPolar Plates (BPPs) are commonly used in Proton Exchange Membrane Water Electrolyzers (PEMWEs) today as they can withstand the harsh operating conditions experienced inside an operating PEM water electrolyzer. In particular, the high anode potential and acidic nature of the PEM is crucial for BPP performance. In this work we expand the investigation of non-coated materials at relevant operating conditions to include molybdenum, 254 SMO, tungsten, AISI 316L, AISI 304L, Inconel 625, niobium and tantalum, in addition to Titanium gr. 2. Pre-designed potentiostatic and potentiodynamic tests at potentials up to 2.0 VSHE were performed in addition to Interfacial Contact Resistance (ICR) and weight loss measurements. Scanning Electron Microscopy (SEM) imaging was conducted to observe morphology changes during the electrochemical tests. Titanium, tantalum and niobium experienced little or no weight change during potentiostatic polarization, while for AISI 304L, AISI 316L and tungsten the measured weight loss was much lower than the weight loss calculated from currents produced. When the potentiostatic test was prolonged for titanium, the ICR was found to increase with time. Auger Electron Spectroscopy measurements confirmed that the increase in ICR for titanium, tantalum and niobium is related to an increased thickness of surface oxides

Measuring In Situ Interfacial Contact Resistance in a Proton Exchange Membrane Fuel Cell

Interfacial contact resistance (ICR) is one of the remaining hurdles for successful implementation of stainless steel bipolar plates in PEM fuel cells. We have developed a reliable method, using thin gold wires, to measure the interfacial contact resistance between the bipolar plate material and the porous transport layer during fuel cell operation. The ICR values were found to be in the same range as the ICR values measured ex situ after fuel cell operation. Local ex situ ICR measurements on tested plates indicate uneven current distribution during fuel cell operation. Consequently, an average between three measuring points was used for the in situ measurements, which enabled consistent monitoring of the ICR development alongside fuel cell performance. For almost all of the tests, the largest ICR changes took place within the first two hours of operation, showing the importance of early ICR measurements. Non-coated stainless steel and titanium-coated steel BPPs experienced a higher ICR compared to the gold coated stainless steel

Measuring In Situ Interfacial Contact Resistance in a Proton Exchange Membrane Fuel Cell

Interfacial contact resistance (ICR) is one of the remaining hurdles for successful implementation of stainless steel bipolar plates in PEM fuel cells. We have developed a reliable method, using thin gold wires, to measure the interfacial contact resistance between the bipolar plate material and the porous transport layer during fuel cell operation. The ICR values were found to be in the same range as the ICR values measured ex situ after fuel cell operation. Local ex situ ICR measurements on tested plates indicate uneven current distribution during fuel cell operation. Consequently, an average between three measuring points was used for the in situ measurements, which enabled consistent monitoring of the ICR development alongside fuel cell performance. For almost all of the tests, the largest ICR changes took place within the first two hours of operation, showing the importance of early ICR measurements. Non-coated stainless steel and titanium-coated steel BPPs experienced a higher ICR compared to the gold coated stainless steel