Incorporating a liquid-core-waveguide cell in recycling liquid chromatography for detailed studies of photodegradation reactions

In this work, a microfluidic photoreactor was embedded in a recycling liquid-chromatography system. Mixtures were separated on an analytical column and compounds of interest were subsequently introduced into the light-reactor cell. After degradation, the content of the light-reactor cell was reinjected onto the same column to separate the parent compound from its degradation products. A separated degradation product could be re-introduced into the photoreactor and irradiated again. The next generation of degradation products could again be separated on the same analytical column. This recycling procedure proved an excellent tool to elucidate degradation pathways. This was demonstrated using riboflavin, better known as vitamin B2. By degrading it in the first cycle, degradation products were isolated and subjected to a second degradation in the light-reactor cell. This allows pinpointing secondary products and connect these with primary degradation products. Compared to previous work, this configuration is simpler, cheaper, and more user-friendly, while offering the unique possibility to easily connect degradation products to the initial compounds in a mixture.</p

Combining Photodegradation in a Liquid-Core-Waveguide Cell with Multiple-Heart-Cut Two-Dimensional Liquid Chromatography

Photodegradation greatly affects everyday life. It poses challenges when food deteriorates or when objects of cultural heritage fade, but it can also create opportunities applied in advanced oxidation processes in water purification. Studying photodegradation, however, can be difficult because of the time needed for degradation, the inaccessibility of pure compounds, and the need to handle samples manually. A novel light-exposure cell, based on liquid-core-waveguide (LCW) technology, was embedded in a multiple-heart-cut two-dimensional liquid chromatography system by coupling the LCW cell to the multiple-heart-cut valve. The sample was flushed from the heart-cut loops into the cell by an isocratic pump. Samples were then irradiated using different time intervals and subsequently transferred by the same isocratic pump to a second-dimension sample loop. The mixture containing the transformation products was then subjected to the second-dimension separation. In the current setup, about 30-40% of the selected fraction was transferred. Multiple degradation products could be monitored. Degradation was found to be faster when a smaller sample amount was introduced (0.3 μg as compared to 1.5 μg). The system was tested with three applications, that is, fuchsin, a 19th-century synthetic organic colorant, annatto, a lipophilic food dye, and vitamin B complex

Health-related quality of life and cardiac rehabilitation: Does body mass index matter?

OBJECTIVE: To investigate the relation between body mass index class and changes in health-related quality of life in patients participating in cardiac rehabilitation. DESIGN: Prospective cohort study. PATIENTS: A total of 503 patients with acute coronary syndrome. METHODS: Data from the OPTICARE trial were used, in which health-related quality of life was measured with the MacNew Heart Disease HRQOL Instrument at the start, directly after, and 9 months after completion of cardiac rehabilitation. Patients were classed as normal weight, overweight, or obese. RESULTS: During cardiac rehabilitation, global health-related quality of life improved in patients in all classes of body mass index. Patients classed as overweight had a significantly greater improvement in social participation than those classed as normal weight (5.51-6.02 compared with 5.73-5.93, respectively; difference in change 0.30, p = 0.025). After completion of cardiac rehabilitation, health-related quality of life continued to improve similarly in patients in all classes of body mass index. CONCLUSION: Health-related quality of life improved during cardiac rehabilitation in patients of all classes of body mass index. Patients classed as overweight showed the greatest improvement. The beneficial effects were maintained during extended follow-up after completion of cardiac rehabilitation

Impact of left atrial volume, sphericity, and fibrosis on the outcome of catheter ablation for atrial fibrillation

INTRODUCTION: To investigate the relation between left atrial (LA) volume, sphericity, and fibrotic content derived from contrast-enhanced cardiac magnetic resonance imaging (CE-CMR) and their impact on the outcome of catheter ablation for atrial fibrillation (AF). METHODS AND RESULTS: In 83 patients undergoing catheter ablation for AF, CE-CMR was used to assess LA volume, sphericity, and fibrosis. There was a significant correlation between LA volume and sphericity (R = 0.535, P < 0.001) and between LA volume and fibrosis (R = 0.241, P = 0.029). Multivariate analyses demonstrated that LA volume was the strongest independent predictor of AF recurrence after catheter ablation (1.019, P = 0.018). CONCLUSION: LA volume, sphericity, and fibrosis were closely related; however, LA volume was the strongest predictor of AF recurrence after catheter ablation

Association Between Exercise Capacity and Health-Related Quality of Life During and After Cardiac Rehabilitation in Acute Coronary Syndrome Patients: A Substudy of the OPTICARE Randomized Controlled Trial

Objective: To examine the strength of the association between exercise capacity and health-related quality of life (HRQOL) during and after cardiac rehabilitation (CR) in patients with acute coronary syndrome (ACS) who completed CR. Design: Prospective cohort study. Setting: Outpatient CR center. Participants: Patients (N=607) with ACS who completed CR. Interventions: Multidisciplinary 12-week exercise-based CR program. Main Outcome Measures: At baseline (pre-CR), the 6-Minute Walk Test (6MWT) was performed to determine exercise capacity, and the MacNew Heart Disease Health-related Quality of Life questionnaire was used to assess HRQOL. Measurements were repeated immediately after completion of CR (post-CR): at 12 months and 18 months follow-up. Multivariable linear regression, including an interaction term for time and exercise capacity, was applied to study the association between exercise capacity and HRQOL at different time points relative to CR, whereas model parameters were estimated by methods that accounted for dependency of repeated observations within individuals. Results: Mean age in years ± SD was 58±8.9 and 82% of participants were male. Baseline mean 6MWT distance in meters ± SD was 563±77 and median (25th-75th percentile) global HRQOL was 5.5 (4.6-6.1) points. Mean 6MWT distance (P<.001) and the global (P<.001), physical (P<.001), emotional (P<.001) and social (P<.001) domains of HRQOL improved significantly during CR and continued to improve during follow-up post-CR. Independent of the timing relative to CR (ie, pre-CR, post-CR, or during follow-up), a difference of 10 m 6MWT distance was associated with a mean difference in the global HRQOL domain of 0.007 (95% confidence interval [CI], 0.001-0.014) points (P=.029) and a mean difference in the physical domain of 0.009 (95% CI, 0.001-0.017) points (P=.023). Conclusions: Better exercise capacity was significantly associated with higher scores on the global and physical domains of HRQOL, irrespective of the timing relative to CR, albeit these associations were weak. Hence, CR programs in secondary prevention should continue to aim at enhancing both HRQOL and exercise capacity

Effect of Weld Schedule on the Residual Stress Distribution of Boron Steel Spot Welds

Press-hardened boron steel has been utilized in anti-intrusion systems in automobiles, providing high strength and weight-saving potential through gage reduction. Boron steel spot welds exhibit a soft heat-affected zone which is surrounded by a hard nugget and outlying base material. This soft zone reduces the strength of the weld and makes it susceptible to failure. Additionally, different welding regimes lead to significantly different hardness distributions, making failure prediction difficult. Boron steel sheets, welded with fixed and adaptive schedules, were characterized. These are the first experimentally determined residual stress distributions for boron steel resistance spot welds which have been reported. Residual strains were measured using neutron diffraction, and the hardness distributions were measured on the same welds. Additionally, similar measurements were performed on spot welded DP600 steel as a reference material. A correspondence between residual stress and hardness profiles was observed for all welds. A significant difference in material properties was observed between the fixed schedule and adaptively welded boron steel samples, which could potentially lead to a difference in failure loads between the two boron steel welds

Characterization of Loading Responses and Failure Loci of a Boron Steel Spot Weld

Boron steel, classed as an ultra high-strength steel (UHSS), has been utilized in anti-intrusion systems in automobiles, providing high strength and weight-saving potential through gage reduction. UHSS spot welds exhibit unique hardness distributions, with a hard nugget and outlying base material, but with a soft heat-affected zone in-between these regions. This soft zone reduces the strength of the weld and makes it susceptible to failure. Due to the interaction of various weld zones that occurs during loading, there is a need to characterize the loading response of the weld for accurate failure predictions. The loading response of certain weld zones, as well as failure loci, was obtained through physical simulation of the welding process. The results showed a significant difference in mechanical behavior through the weld length. An important result is that instrumented indentation was shown to be a valid, quantitative method for verifying the accuracy with which weld microstructure has been recreated with regard to the target weld microstructure

Outcome in moderate haemophilia.

BACKGROUND: Moderate haemophilia is the rarest form of haemophilia. This study aims to assess short- and long-term outcome, including its association with treatment, in patients with moderate haemophilia. MATERIAL AND METHODS: Seventy-five patients with moderate haemophilia (1-5% factor VIII/ factor IX activity), without a history of inhibitors, treated at the van Creveldkliniek, Utrecht (NL) were included in the study. Life-long data on bleeding and treatment were collected. Joints were evaluated using the Haemophilia Joint Health Score. Adults completed questionnaires on activity (HAL) and quality of life (SF-36, EQ5D). RESULTS: The median age of the patients was 37 years (IQR 23-52 years) and haemophilia A was diagnosed in 89%. Bleeding frequency was low: the median annual bleeding rate was 2.0 bleeds/ year (IQR 0.8-3.7 bleeds/year), including a median of 0 joint bleeds/year (IQR 0.8-3.7 bleeds/year). Joint function was good: 82% scored<10 out of 126 points of the Haemophilia Joint Health Score (HJHS). Nevertheless, 29% of patients with moderate haemophilia had a history of prophylaxis, because of a high bleeding frequency. Median age at first joint bleed was 4.8 years (IQR 3.5-8.5). Use of prophylaxis was more associated with age at first joint bleed (P<0.01) than with baseline factor activity (P=0.12). Most patients (52%) who suffered their first joint bleed before the age of 5 years required prophylaxis later in life. DISCUSSION: The majority of patients with moderate haemophilia have few bleeds and complications; however, a considerable subset of patients with a more severe bleeding pattern need prophylactic treatment. These latter patients may be identified by the onset of joint bleeding before the age of 5 years

Turning severe into moderate haemophilia by prophylaxis: are we reaching our goal?

BACKGROUND: Since the introduction of prophylaxis, physicians have tried to convert the clinical phenotype of severe haemophilia (SH) into that of moderate haemophilia (MH), but the outcome of patients with SH has never been compared to that of patients with MH. MATERIAL AND METHODS: The outcome of 80 patients with SH on long-term, intermediate dose prophylaxis was compared to that of 40 patients with MH in a single-centre study. Data on treatment history, activities (assessed by the IPAQ and HAL), quality of life (assessed by the SF-36 and EQ5D), and 5-year bleeding and clotting factor consumption were collected for patients born between 1970-1995. RESULTS: The median age of the patients was 24 years (IQR 18-30). All patients with SH received long-term prophylaxis, which was started at a median age of 4.8 years (IQR 3.2-6.2). Among the patients with MH, ten (25%) received prophylaxis, starting at a median age of 10.8 years (IQR 3.8-13.8). The annual number of bleeds, including joint bleeds, was significantly higher in patients with SH (median 2.0 joint bleeds/year, IQR =0.8-3.7) than in patients with MH (median 0.8 joint bleeds/year, IQR =0-1.2). Due to greater use of prophylaxis, the annual clotting factor consumption of SH patients (median 2,120 IU/kg; IQR 1,514-2,768), was higher than that of MH patients (median 133 IU/kg; IQR 49-468). Patients with SH showed slightly but significantly more loss of clinical function (assessed by the Haemophilia Joint Health Score): a median of 8 points (IQR 3-15) vs a median of 2 points, IQR 0-6). Quality of life, as measured by the SF-36, EQ5D and physical activity, was similar between patients with disease of different severity, as well as compared to that of the general population. DISCUSSION: When comparing unselected cohorts, the bleeding pattern of patients with SH does not appear to be fully converted to that of the milder bleeding pattern of MH by long-term, intermediate-dose prophylaxis, although activities and quality of life were similar