Novel catalytic materials for carbon dioxide reforming of methane under severely deactivating conditions.

Promotion of the ZrO2 support with cerium and lanthanum resulted in increased activity and stability of the catalyst. The improved performance of the promoted catalyst can be attributed stabilizing the surface area for high temperature operation, increasing the density of CO2 adsorption sites near the metal particle, and retarding particle growth under reaction conditions.In recent years, the utilization of carbon dioxide for the reforming of methane (dry reforming) has attracted significant interest due to the industrial advantages over conventional steam reforming. The major obstacle preventing commercialization of this process is the lack of a catalyst capable of operating at the high temperatures and pressures required by industry.This thesis reports the study of the dry reforming reaction over SiO 2 and ZrO2 supported Pt catalysts. It was found that the Pt/ZrO2 catalyst had much higher activity and stability than the Pt/SiO2 catalyst due to the ability of the ZrO2 to adsorb CO2 near the metal particle, facilitating its dissociation. The decomposition of CH4 and the dissociation of CO2 occur via two independent pathways. CH4 decomposition occurs on the metal particle resulting in the formation of H2 and carbon deposition. When Pt is supported on ZrO2, the carbon formed during the decomposition of CH4 can reduce the support to form CO2 creating oxygen vacancies in the support lattice near the metal particle. The adsorption and dissociation of CO2 occurs at the vacancies, forming CO and replenishing the oxygen in the support lattice. This redox mechanism results in a cleaning of the metal particle by oxygen provided by the support. Promoters were added to both the metallic phase and to the support to improve the stability of the catalyst by decreasing carbon deposition. The co-impregnation of Sn and Pt on the ZrO2 resulted in lower activity and stability than the monometallic catalysts. Under oxidizing conditions, segregation of the Pt-Sn alloys occurred, resulting in the formation of tin oxide inhibiting the role of the ZrO2. Catalysts prepared by methods that allow for the controlled placement of Sn on the Pt particle, exhibited high activity and stability under severely deactivating conditions

Adaptive Global Carbon Monoxide Kinetic Mechanism over Platinum/Alumina Catalysts

Carbon monoxide (CO) oxidation is one of the more widely researched mechanisms given its pertinence across many industrial platforms. Because of this, ample information exists as to the detailed reaction steps in its mechanism. While detailed kinetic mechanisms are more accurate and can be written as a function of catalytic material on the surface, global mechanisms are more widely used because of their computational efficiency advantage. This paper merges the theory behind detailed kinetics into a global kinetic model for the singular CO oxidation reaction while formulating expressions that adapt to catalyst properties on the surface such as dispersion and precious metal loading. Results illustrate that the model is able to predict the light-off and extinction temperatures during a hysteresis experiment as a function of different inlet CO concentrations and precious metal dispersion

Mixed-conducting oxygen permeable ceramic membranes for the carbon dioxide reforming of methane

This is the published version. Copyright 2007 Royal Society of ChemistryDue to the high economic, environmental, and safety costs associated with pure oxygen, mixed-conducting oxygen-permeable ceramic membranes are being explored as an alternative oxygen source for hydrocarbon conversion reactors. This work reports a dramatic improvement in catalyst performance when an oxygen-permeable SrFeCo0.5Ox ceramic membrane is used in conjunction with a conventional powder Pt/ZrO2 catalyst for the CO2 reforming of CH4. Experiments comparing catalyst performance with up to 2% co-fed oxygen to catalyst performance with oxygen from the ceramic membrane demonstrated a conversion three times higher with the membrane than with any amount of co-fed oxygen. The results suggest that membrane oxygen is more beneficial for catalyst activity and stability than molecular gas-phase oxygen

Sleep-Disordered Breathing and Gestational Diabetes Mellitus: A meta-analysis of 9,795 participants enrolled in epidemiological observational studies

OBJECTIVE Recently, sleep-disordered breathing (SDB) has been reported to be associated with the development of gestational diabetes mellitus (GDM). Accordingly, as this is emergent area of research that has significant clinical relevance, the objective of this meta-analysis is to examine the relationship between SDB with GDM. RESEARCH DESIGN AND METHODS We searched several electronic databases for all of the studies published before January 2013 and reviewed references of published articles. Meta-analytic procedures were used to estimate the unadjusted and BMI-adjusted odds ratios (ORs) using a random effects model. Significant values, weighted effect sizes, and 95% CIs were calculated, and tests of homogeneity of variance were performed. RESULTS Results from nine independent studies with a total of 9,795 pregnant women showed that SDB was significantly associated with an increased risk of GDM. Women with SDB had a more than threefold increased risk of GDM, with a pooled BMI-adjusted OR 3.06 (95% CI 1.89–4.96). CONCLUSIONS These findings demonstrate a significant association between SDB and GDM that is evident even after considered confounding by obesity. This meta-analysis indicates a need to evaluate the role of early recognition and treatment of SDB early during pregnancy

Maternal Early Pregnancy Serum Metabolomics Profile and Abnormal Vaginal Bleeding as Predictors of Placental Abruption: A Prospective Study

Background & Objective Placental abruption, an ischemic placental disorder, complicates about 1 in 100 pregnancies, and is an important cause of maternal and perinatal morbidity and mortality worldwide. Metabolomics holds promise for improving the phenotyping, prediction and understanding of pathophysiologic mechanisms of complex clinical disorders including abruption. We sought to evaluate maternal early pregnancy pre-diagnostic serum metabolic profiles and abnormal vaginal bleeding as predictors of abruption later in pregnancy. Methods Maternal serum was collected in early pregnancy (mean 16 weeks, range 15 to 22 weeks) from 51 abruption cases and 51 controls. Quantitative targeted metabolic profiles of serum were acquired using electrospray ionization liquid chromatography-mass spectrometry (ESI-LC-MS/MS) and the Absolute IDQ® p180 kit. Maternal sociodemographic characteristics and reproductive history were abstracted from medical records. Stepwise logistic regression models were developed to evaluate the extent to which metabolites aid in the prediction of abruption. We evaluated the predictive performance of the set of selected metabolites using a receiver operating characteristics (ROC) curve analysis and area under the curve (AUC). Results Early pregnancy vaginal bleeding, dodecanoylcarnitine/dodecenoylcarnitine (C12 / C12:1), and phosphatidylcholine acyl-alkyl C 38:1 (PC ae C38:1) strongly predict abruption risk. The AUC for these metabolites alone was 0.68, for early pregnancy vaginal bleeding alone was 0.65, and combined the AUC improved to 0.75 with the addition of quantitative metabolite data (P = 0.003). Conclusion Metabolomic profiles of early pregnancy maternal serum samples in addition to the clinical symptom, vaginal bleeding, may serve as important markers for the prediction of abruption. Larger studies are necessary to corroborate and validate these findings in other cohorts

Racial/Ethnic Differences in Sleep Disturbances: The Multi-Ethnic Study of Atherosclerosis (MESA)

Objectives: There is limited research on racial/ethnic variation in sleep disturbances. This study aimed to quantify the distributions of objectively measured sleep disordered breathing (SDB), short sleep duration, poor sleep quality, and self-reported sleep disturbances (e.g., insomnia) across racial/ethnic groups. Design: Cross-sectional study. Setting: Six US communities. Participants: Racially/ethnically diverse men and women aged 54–93 y in the Multi-Ethnic Study of Atherosclerosis Sleep Cohort (n = 2,230). Interventions: N/A. Measurements and Results: Information from polysomnography-measured SDB, actigraphy-measured sleep duration and quality, and selfreported daytime sleepiness were obtained between 2010 and 2013. Overall, 15.0% of individuals had severe SDB (apnea-hypopnea index [AHI] ≥ 30); 30.9% short sleep duration (< 6 h); 6.5% poor sleep quality (sleep efficiency <85%); and 13.9% had daytime sleepiness. Compared with Whites, Blacks had higher odds of sleep apnea syndrome (AHI ≥ 5 plus sleepiness) (sex-, age-, and study site-adjusted odds ratio [OR] = 1.78, 95% confidence interval [CI]: 1.20, 2.63), short sleep (OR = 4.95, 95% CI: 3.56, 6.90), poor sleep quality (OR = 1.57, 95% CI: 1.00, 2.48), and daytime sleepiness (OR = 1.89, 95% CI: 1.38, 2.60). Hispanics and Chinese had higher odds of SDB and short sleep than Whites. Among nonobese individuals, Chinese had the highest odds of SDB compared to Whites. Only 7.4% to 16.2% of individuals with an AHI ≥ 15 reported a prior diagnosis of sleep apnea. Conclusions: Sleep disturbances are prevalent among middle-aged and older adults, and vary by race/ethnicity, sex, and obesity status. The high prevalence of sleep disturbances and undiagnosed sleep apnea among racial/ethnic minorities may contribute to health disparities. Keywords: apnea-hypopnea index, body mass index, daytime sleepiness, obesity, polysomnography, race/ethnicity, sleep disordered breathing, sleep disturbance, sleep duration, sleep qualit

Attitudes, beliefs, and perceptions of caregivers and rehabilitation providers about disabled children’s sleep health: a qualitative study

Children with disabilities are more likely to have sleep disturbances than children without disabilities. Identifying attitudes, beliefs, knowledge, and perceptions of caregivers and health professionals is essential in developing effective intervention programs to improve disabled children’s sleep health. However, no such qualitative data about adults who have key roles in the life and daytime activities of children with disabilities are available. This qualitative study aimed to understand attitudes, beliefs, knowledge, and perceptions about disabled children’s sleep hygiene among caregivers and rehabilitation providers of children with disabilities. Twenty seven adults, including nine primary caregivers and eighteen rehabilitation providers, participated in five focus group discussions between September and December 2012 at the Rehabilitation Center in Punta Arenas, Chile. A trained facilitator guided focus group discussions using a semi-structured script. Audiotapes and transcripts of focus group discussions were reviewed and analyzed for recurrent themes. Participants identified seven themes related to children’s sleep hygiene: lifestyle behaviors, family factors, children’s disabilities and/or comorbidities, environmental factors, adults’ responsibilities for children’s sleep, perception of good sleep, and parental distress about children’s sleep problems. While both caregivers and rehabilitation providers recognized the importance of sleep for children’s health and functioning, they differed in their understanding of how sleep hygiene practices influence sleep. Rehabilitation providers recognized the negative influence of electronics on sleep and the positive influence of sleep routines. In contrast, caregivers reported use of television/movie watching and stimulants as coping strategies for managing children’s sleep problems. Caregivers may benefit from better understanding the influence of electronics and stimulant use on child sleep health. Rehabilitation providers are well positioned to provide educational messages to both children and caregivers in order to change their attitudes, perceptions, and practices surrounding sleep. These qualitative data are valuable in developing intervention programs aimed at improving sleep health among children with disabilities

Using online patient feedback to improve NHS services : the INQUIRE multimethod study

Background Online customer feedback has become routine in many industries, but it has yet to be harnessed for service improvement in health care. Objectives To identify the current evidence on online patient feedback; to identify public and health professional attitudes and behaviour in relation to online patient feedback; to explore the experiences of patients in providing online feedback to the NHS; and to examine the practices and processes of online patient feedback within NHS trusts. Design A multimethod programme of five studies: (1) evidence synthesis and stakeholder consultation; (2) questionnaire survey of the public; (3) qualitative study of patients’ and carers’ experiences of creating and using online comment; (4) questionnaire surveys and a focus group of health-care professionals; and (5) ethnographic organisational case studies with four NHS secondary care provider organisations. Setting The UK. Methods We searched bibliographic databases and conducted hand-searches to January 2018. Synthesis was guided by themes arising from consultation with 15 stakeholders. We conducted a face-to-face survey of a representative sample of the UK population (n = 2036) and 37 purposively sampled qualitative semistructured interviews with people with experience of online feedback. We conducted online surveys of 1001 quota-sampled doctors and 749 nurses or midwives, and a focus group with five allied health professionals. We conducted ethnographic case studies at four NHS trusts, with a researcher spending 6–10 weeks at each site. Results Many people (42% of internet users in the general population) read online feedback from other patients. Fewer people (8%) write online feedback, but when they do one of their main reasons is to give praise. Most online feedback is positive in its tone and people describe caring about the NHS and wanting to help it (‘caring for care’). They also want their feedback to elicit a response as part of a conversation. Many professionals, especially doctors, are cautious about online feedback, believing it to be mainly critical and unrepresentative, and rarely encourage it. From a NHS trust perspective, online patient feedback is creating new forms of response-ability (organisations needing the infrastructure to address multiple channels and increasing amounts of online feedback) and responsivity (ensuring responses are swift and publicly visible). Limitations This work provides only a cross-sectional snapshot of a fast-emerging phenomenon. Questionnaire surveys can be limited by response bias. The quota sample of doctors and volunteer sample of nurses may not be representative. The ethnographic work was limited in its interrogation of differences between sites. Conclusions Providing and using online feedback are becoming more common for patients who are often motivated to give praise and to help the NHS improve, but health organisations and professionals are cautious and not fully prepared to use online feedback for service improvement. We identified several disconnections between patient motivations and staff and organisational perspectives, which will need to be resolved if NHS services are to engage with this source of constructive criticism and commentary from patient

Parasitic Disease Surveillance, Mississippi, USA

Surveillance for soil-transmitted helminths, strongyloidiasis, cryptosporidiosis, and giardiasis was conducted in Mississippi, USA. PCR performed on 224 fecal samples for all soil-transmitted helminths and on 370 samples for only Necator americanus and Strongyloides stercoralis identified 1 S. stercoralis infection. Seroprevalences were 8.8% for Toxocara, 27.4% for Cryptosporidium, 5.7% for Giardia, and 0.2% for Strongyloides parasites

Parasitic Infection Surveillance in Mississippi Delta Children

Some recent studies suggest ongoing transmission of parasitic diseases in the American South; however, surveys in Mississippi children are lacking. We enrolled 166 children (median age 8 years, range 4–13 years) from the Mississippi Delta region and carried out multi-parallel real-time polymerase chain reaction (PCR) for Necator americanus, Ascaris lumbricoides, and Strongyloides stercoralis on their stool samples. Dried blood spots were obtained for multiplex serology antibody detection. Of 166 children, all reported having flushable toilets, 11% had soil exposure, and 34% had a pet dog or cat. None had prior diagnosis or treatment of parasitic disease. Multi-parallel real-time PCRs were negative on the 89 stool DNA extracts available for testing. Dried blood spot testing of all 166 children determined the seroprevalence of IgG antibodies to Toxocara spp. (3.6%), Cryptosporidium (2.4%), S. stercoralis, Fasciola hepatica, and Giardia duodenalis (all 0%). In conclusion, parasitic infections and exposure were scarce in this population. Larger studies of at-risk populations are needed