Effect of ceria and zirconia on nanoparticulate rhodium catalysts

Rh metal was implemented as a core component in the so-called three-way automotive exhaust catalyst (TWC) due to its excellent properties such as thermal stability, poison resistance and inert behaviour to react with any support materials. These catalysts are often loaded with small amount of promoter elements such as Ce and Zr that enhance their overall catalytic performances and catalyst lifetime. It is therefore desirable to develop new CeOx-based catalyst with both high redox activity and high thermal resistance.Samples of two surface coverages of rhodium on a non-porous high area alumina been synthesised; at 1.6 Rh and 4 wt % Rh loading. Ceria and zirconia have been deposited on the pre-supported Rh catalysts by the controlled surface reaction between the reduced Rh surface and an organometallic precursors: Zr(acac)4 and Ce(acac)3, with different cerium : zirconium ratios: Ce:Zr;1:0, 1:1, 2:1, 0:1. Ceriated Rh catalysts have been also prepared by a different synthesis method, wherein the ceria was deposited on ?-Al2O3 and subsequently Rh metal was added. A series of Rh catalysts produced has been characterised ex situ by BET surface area measurement, TEM, STEM HAADF, EDX, XPS, and XAFS.The combination of Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), Mass Spectrometry (MS) and Energy Dispersive X-ray Absorption Fine Structure (EDE) techniques in a synchronous, time-resolved manner has been applied to determine the complementary information about structural and kinetic changes of the chemical system throughout CO exposure and two catalytic processes: CO oxidation and the reduction of NO by CO in the temperature range between 298 K to 573 K.It has been shown that advanced characterisation techniques, used in the time-resolved, in situ manner were needed in order to understand the behaviour of these complex catalytic systems under operating conditions. The effects of the catalysts’ composition, temperature and pulsed gas flow on catalyst performance have been effectively mapped by the combined DRIFTS/MS/EDE studies. The synthesis procedure has been found to be crucial to achieve the desired interaction between CeOx and Rh particles. No enhancement of ceriated Rh catalysts was observed when ceria was deposited directly on ?-Al2O3 (method I). The addition of each promoter element by the controlled surface modification procedure (method II) exhibits multiple effects on the catalysts performance. The DRIFTS/XAFS studies have confirmed that CeOx and ZrO2 facilitate the protection of Rh particles against extensive oxidation in atmospheres of air, O2 and CO. Larger Rh core particles of ceriated and zirconiated Rh catalysts have been observed when compared with undoped Rh samples. DRIFTS results indicate that by interaction of CO with Rh particles a significantly larger amount of linear CO species was formed on the ceriated Rh surface than in the non-ceriated Rh catalysts case suggesting the presence of predominant metallic Rh phase for that system. Moreover, only ceria doping was found to improve the catalytic activity of promoted Rh catalysts throughout CO oxidation in the temperature ramp mode under different (O2/CO) gas composition

Hemophilic Siblings With Chronic Hepatitis C: Familial Aggregation of Spontaneous and Treatment-Related Viral Clearance

Hemophilic siblings provide a unique population to explore the natural history of chronic hepatitis C

An evaluation of patient-reported outcomes in sickle cell disease within a conceptual model.

PURPOSE: To examine the relations between patient-reported outcomes (PROs) within a conceptual model for adults with sickle cell disease (SCD) ages 18 - 45 years enrolled in the multi-site Sickle Cell Disease Implementation Consortium (SCDIC) registry. We hypothesized that patient and SCD-related factors, particularly pain, and barriers to care would independently contribute to functioning as measured using PRO domains. METHODS: Participants (N = 2054) completed a 48-item survey including socio-demographics and PRO measures, e.g., social functioning, pain impact, emotional distress, and cognitive functioning. Participants reported on lifetime SCD complications, pain episode frequency and severity, and barriers to healthcare. RESULTS: Higher pain frequency was associated with higher odds of worse outcomes in all PRO domains, controlling for age, gender and site (OR range 1.02-1.10, 95% CI range [1.004-1.12]). Reported history of treatment for depression was associated with 5 of 7 PRO measures (OR range 1.58-3.28 95% CI range [1.18-4.32]). Fewer individual barriers to care and fewer SCD complications were associated with better outcomes in the emotion domain (OR range 0.46-0.64, 95% CI range [0.34-0.86]). CONCLUSIONS: Study results highlight the importance of the biopsychosocial model to enhance understanding of the needs of this complex population, and to design multi-dimensional approaches for providing more effective interventions to improve outcomes

Patient Reported Outcomes in Sickle Cell Disease Examined Within a Conceptual Model

Objective: To examine the relations between patient reported outcomes (PROs) within a conceptual model for adults with sickle cell disease (SCD) ages 18 – 45 years enrolled in the Sickle Cell Disease Implementation Consortium (SCDIC) registry. We hypothesized that patient and SCD related factors and barriers to care would independently contribute to functioning as measured using the PRO domains. Additionally, pain and other SCD related complications are expected to impact the relation between the variables. Methods: Participants completed a 48-item survey that included socio-demographics and PRO measures, such as social functioning, pain impact emotional distress, and cognitive functioning. Participants reported on lifetime SCD complications, pain episode frequency, timing and severity, and barriers to medical care. Healthcare utilization was obtained from medical records abstractions. Results: Higher pain frequency and severity and history of treatment for depression were associated with higher odds of worse outcomes in almost all PRO domains, controlling for age and gender for the 2,054 participants. Such social determinants of health as lower household income and unemployment, particularly due to disability status, were associated with higher odds of worse outcomes. Reports of fewer individual barriers to care were associated with better outcomes in emotion, social, cognitive and fatigue domains, while reports of fewer self-reported SCD complications/treatments were associated with better outcomes in emotion and sleep impact domains. Conclusions: Study results highlight the importance of the biopsychosocial model to enhance understanding of the needs of this complex population, and to design multi-dimensional approaches for providing more effective interventions to improve outcomes. @font-face {font-family: Cambria Math ; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-536870145 1107305727 0 0 415 0;}@font-face {font-family:Times; panose-1:2 0 5 0 0 0 0 0 0 0; mso-font-charset:0; mso-generic-font-family:auto; mso-font-pitch:variable; mso-font-signature:-536870145 1342185562 0 0 415 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent: ; margin:0in; mso-pagination:widow-orphan; font-size:12.0pt; font-family: Times New Roman ,serif; mso-fareast-font-family: Times New Roman ;}.MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-family: Calibri ,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Calibri; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family: Times New Roman ; mso-bidi-theme-font:minor-bidi;}div.WordSection1 {page:WordSection1;

Bicuspid and unicuspid aortic valves: Different phenotypes of the same disease? Insight from the GenTAC Registry

BackgroundUnicuspid aortic valve (UAV) is a rare disorder, often difficult to distinguish from bicuspid aortic valve (BAV). BAV and UAV share valve pathology such as the presence of a raphe, leaflet fusion, aortic stenosis, aortic regurgitation, and/or ascending aortic dilatation, but a comprehensive echocardiographic comparison of patients with UAV and BAV has not been previously performed.MethodsWe investigated UAV and BAV patients at an early stage of disease included in GenTAC, a national registry of genetically related aortic aneurysms and associated cardiac conditions. Clinical and echocardiographic data from the GenTAC Registry were compared between 17 patients with UAV and 17 matched‐controls with BAV.ResultsBaseline characteristics including demographics, clinical findings including family history of BAV and aortic aneurysm/coarctation, and echocardiographic variables were similar between BAV and UAV patients; aortic stenosis was more common and more severe in patients with UAV. This was evidenced by higher mean and peak gradient, smaller aortic valve area, and more advanced valvular degeneration (all P < .05). There were no significant differences in aortic dimensions, with a similar pattern of enlargement of the ascending aorta.ConclusionsThe similar baseline characteristics with more accelerated aortic valve degeneration and stenosis suggest that UAV represents an extreme in the spectrum of BAV syndromes. Therefore, it is reasonable to consider application of recommendations for the management of patients with BAV to those with the rarer UAV.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139976/1/chd12520.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139976/2/chd12520_am.pd

GenTAC registry report: Gender differences among individuals with genetically triggered thoracic aortic aneurysm and dissection

Previous data suggest women are at increased risk of death from aortic dissection. Therefore, we analyzed data from the GenTAC registry, the NIH‐sponsored program that collects information about individuals with genetically triggered thoracic aortic aneurysms and cardiovascular conditions. We performed cross‐sectional analyses in adults with Marfan syndrome (MFS), familial thoracic aortic aneurysm or dissection (FTAAD), bicuspid aortic valve (BAV) with thoracic aortic aneurysm or dissection, and subjects under 50 years of age with thoracic aortic aneurysm or dissection (TAAD <50 years). Women comprised 32% of 1,449 subjects and were 21% of subjects with BAV, 34% with FTAAD, 22% with TAAD <50 years, and 47% with MFS. Thoracic aortic dissections occurred with equal gender frequency yet women with BAV had more extensive dissections. Aortic size was smaller in women but was similar after controlling for BSA. Age at operation for aortic valve dysfunction, aneurysm or dissection did not differ by gender. Multivariate analysis (adjusting for age, BSA, hypertension, study site, diabetes, and subgroup diagnoses) showed that women had fewer total aortic surgeries (OR = 0.65, P  < 0.01) and were less likely to receive angiotensin converting enzyme inhibitors (ACEi; OR = 0.68, P  < 0.05). As in BAV, other genetically triggered aortic diseases such as FTAAD and TAAD <50 are more common in males. In women, decreased prevalence of aortic operations and less treatment with ACEi may be due to their smaller absolute aortic diameters. Longitudinal studies are needed to determine if women are at higher risk for adverse events. © 2013 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97193/1/35836_ftp.pd

Racial and socioeconomic disparities in epilepsy in the District of Columbia

PURPOSE: Few studies have found differences in rates of epilepsy by race or ethnicity although previous reports indicate strong links between epilepsy and socioeconomic indicators. We investigated social and demographic factors as they relate to prevalence and incidence of epilepsy in Washington, DC, a culturally diverse area. METHODS: Probability-based sampling was used to select 20,000 DC households that were mailed an epilepsy screening survey. Demographic and epilepsy data were obtained on all household members. Screened individuals with a history of epilepsy or seizure disorder were sent a case survey asking more detailed questions about seizures and treatment which were used to verify case status using the standard case definition. Survey data were weighted to match characteristics of DC residents. Lifetime and active prevalence and incidence of epilepsy were estimated using weighted data and appropriate survey procedures in SAS. KEY FINDINGS: Overall survey response rate was 36.6%. 208 cases of epilepsy were identified during screening and 14% with a case survey were considered false positive. Using the verified dataset, lifetime prevalence was 1.53% overall; 0.77% in Whites, 2.13% in Blacks, 3.4% in those with less than a high school diploma, and 2.27% in those with household income less than $30,000. Overall prevalence of active epilepsy was 0.79% and followed similar subgroup comparisons as lifetime prevalence. Age-adjusted lifetime and active epilepsy from multivariate analyses demonstrated significantly higher rates for Blacks compared to Whites and for those not completing high school compared to those that attended graduate school. The overall incidence of epilepsy was 71 per 100,000 persons. Adults with active epilepsy were significantly less likely to live alone than those without epilepsy (36.0% versus 46.1%). Residents of DC for less than four years had the lowest prevalence and incidence of all subgroups indicating a possible healthy mover effect. SIGNIFICANCE: Our study is the first to provide region-specific estimates and profiles of the epilepsy population in DC which can help inform policy makers and healthcare providers on where to better target resources to improve the health and outcomes of people with epilepsy and their families