221 research outputs found

    Adsorption of hydrogen sulphide over rhodium/silica and rhodium/alumina at 293 and 873 K, with co-adsorption of carbon monoxide and hydrogen

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    In this study, we have examined the adsorption of hydrogen sulphide and carbon monoxide over rhodium/silica and rhodium/alumina catalysts. Adsorption of hydrogen sulphide was measured at 293 and 873 K and at 873 K in a 1:1 ratio with hydrogen. At 293 K, over Rh/silica, hydrogen sulphide adsorption capacity was similar to that of carbon monoxide; however, over Rh/alumina, the carbon monoxide adsorption capacity was higher, probably due to the formation of RhI(CO)2. Over Rh/silica, the primary adsorbed state was HS(ads), in contrast to Rh/alumina, where the H2:S ratio was 1:1 indicating that the adsorbed state was S(ads). Competitive adsorption between CO and H2S over Rh/silica and Rh/alumina revealed adsorption sites on the metal that only adsorbed carbon monoxide, only adsorbed hydrogen sulphide or could adsorb both species. At 873 K, hydrogen sulphide adsorption produced the bulk sulphide Rh2S3; however, when a 1:1 H2:H2S mixture was used formation of the bulk sulphide was inhibited and a reduced amount of hydrogen sulphide was adsorbed

    Isolation, characterization, and in vitro propagation of infantile hemangioma stem cells and an in vivo mouse model

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    <p>Abstract</p> <p>Background</p> <p>Infantile hemangiomas (IH) are the most common benign tumors of infancy. The typical clinical course consists of rapid growth during the first year of life, followed by natural and gradual involution over a multi-year time span through unknown cellular mechanisms. Some tumors respond to medical treatment with corticosteroids or beta-blockers, however, when this therapy fails or is incomplete, surgical extirpation may be necessary. Noninvasive therapies to debulk or eliminate these tumors would be an important advance. The development of an <it>in vitro </it>cell culture system and an animal model would allow new insights into the biological processes involved in the development and pathogenesis of IH.</p> <p>Results</p> <p>We observed that proliferative stage IH specimens contain significantly more SALL4+ and CD133+ cells than involuting tumors, suggesting a possible stem cell origin. A tumor sphere formation assay was adapted to culture IH cells <it>in vitro</it>. Cells in IH tumor spheres express GLUT1, indicative of an IH cell of origin, elevated levels of VEGF, and various stem/progenitor cell markers such as SALL4, KDR, Oct4, Nanog and CD133. These cells were able to self-renew and differentiate to endothelial lineages, both hallmarks of tumor stem cells. Treatment with Rapamycin, a potent mTOR/VEGF inhibitor, dramatically suppressed IH cell growth <it>in vitro</it>. Subcutaneous injection of cells from IH tumor spheres into immunodeficient NOD-SCID mice produced GLUT1 and CD31 positive tumors with the same cellular proliferation, differentiation and involution patterns as human hemangiomas.</p> <p>Conclusions</p> <p>The ability to propagate large numbers of IH stem cells <it>in vitro </it>and the generation of an <it>in vivo </it>mouse model provides novel avenues for testing IH therapeutic agents in the future.</p

    Ethane steam reforming over a platinum/alumina catalyst: effect of sulphur poisoning

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    In this study we have examined the adsorption of hydrogen sulfide and methanethiol over platinum catalysts and examined the effect of these poisons on the steam reforming of ethane. Adsorption of hydrogen sulfide was measured at 293 and 873 K. At 873 K the adsorbed state of hydrogen sulfide in the presence of hydrogen was SH rather than S, even though the Pt:S ratio was unity. The effect of 11.2 ppm hydrogen sulfide or methanethiol on the steam reforming of ethane was studied at 873 K and 20 barg. Both poisons deactivated the catalyst over a number of hours, but methanethiol was found to be more deleterious, reducing the conversion by almost an order of magnitude, possibly due to the co-deposition of sulfur and carbon. Changes in the selectivity revealed that the effect of sulfur was not uniform on the reactions occurring, with the production of methane reduced proportionally more than the other products, due to the surface sensitivity of the hydrogenolysis and methanation reactions. The water-gas shift reaction was affected to a lesser extent. No regeneration was observed when hydrogen sulfide was removed from the feedstream in agreement with adsorption studies. A slight regeneration was observed when methanethiol was removed from the feed, but this was believed to be due to the removal of carbon rather than sulfur. The overall effect of sulfur poisoning was to reduce activity and enhance hydrogen selectivity

    Priorities for action on the social determinants of health : Empirical evidence on the strongest associations with life expectancy in 54 low-income countries, 1990–2012

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    The WHO Commission on the Social Determinants of Health set out an impressive collection of policy proposals on the social determinants of health. However, a serious weakness for securing implementation is the difficulty for policymakers in identifying priorities for action. The objective of this study is to determine a small set of the most influential determinants using existing data and an empirical approach. 45 Indicators from the World Bank's World Development Indicators are selected to measure attainment for the determinants proposed by the Commission. Panel data models of life expectancy at birth for 54 low-income countries over the years 1990–2012 (1188 country-years) are estimated. Each determinant is subjected to a robustness test using Extreme Bound Analysis, to determine the stability of its estimated impact on life expectancy. For 20 robust and significant determinants the magnitude of association with life expectancy is determined. The largest average increases in life expectancy at 14.5 months per capita is associated with a one standard deviation reduction in HIV prevalence among children, followed by advances in gender equality at 9.4 months. Improvements in life expectancy between 6 and 9 months are associated with agricultural production, political stability, access to clean water and sanitation, good governance, and primary school enrolment. Improvements below 6 months are associated with increases in private health expenditure and overseas development assistance, and control of armed conflict and HIV prevalence among men. There is no evidence that national income, public spending on healthcare and education, secondary schooling, terms of international trade, employment, debt service and relief, out-of-pocket expenditures, agricultural ex- or imports, lifestock production, foreign investment, urbanization or environmental degradation are robustly associated with population health. Results provide support for the relevance of some proposed policies. The findings can inform priorities for future research and policy action on the social determinants of health

    Reduction of aldehydes and hydrogen cyanide yields in mainstream cigarette smoke using an amine functionalised ion exchange resin

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    <p>Abstract</p> <p>Background</p> <p>Cigarette smoking is a well recognized cause of diseases such as lung cancer, chronic obstructive pulmonary disease and cardiovascular disease. Of the more than 5000 identified species in cigarette smoke, at least 150 have toxicological activity. For example, formaldehyde and acetaldehyde have been assigned as Group 1 and Group 2B carcinogens by IARC, and hydrogen cyanide has been identified as a respiratory and cardiovascular toxicant. Active carbon has been shown to be an effective material for the physical adsorption of many of the smoke volatile species. However, physical adsorption of acetaldehyde, formaldehyde and also hydrogen cyanide from smoke is less effective using carbon. Alternative methods for the removal of these species from cigarette smoke are therefore of interest. A macroporous, polystyrene based ion-exchange resin (Diaion<sup>®</sup>CR20) with surface amine group functionality has been investigated for its ability to react with aldehydes and HCN in an aerosol stream, and thus selectively reduce the yields of these compounds (in particular formaldehyde) in mainstream cigarette smoke.</p> <p>Results</p> <p>Resin surface chemistry was characterized using vapour sorption, XPS, TOF-SIMS and <sup>15</sup>N NMR. Diaion<sup>®</sup>CR20 was found to have structural characteristics indicating weak physisorption properties, but sufficient surface functionalities to selectively remove aldehydes and HCN from cigarette smoke. Using 60 mg of Diaion<sup>®</sup>CR20 in a cigarette cavity filter gave reductions in smoke formaldehyde greater than 50% (estimated to be equivalent to >80% of the formaldehyde present in the smoke vapour phase) independent of a range of flow rates. Substantial removal of HCN (>80%) and acetaldehyde (>60%) was also observed. The performance of Diaion<sup>®</sup>CR20 was found to be consistent over a test period of 6 months. The overall adsorption for the majority of smoke compounds measured appeared to follow a pseudo-first order approximation to second order kinetics.</p> <p>Conclusions</p> <p>This study has shown that Diaion<sup>®</sup>CR20 is a highly selective and efficient adsorbent for formaldehyde, acetaldehyde and HCN in cigarette smoke. The reductions for these compounds were greater than those achieved using an active carbon. The results also demonstrate that chemisorption can be an effective mechanism for the removal of certain vapour phase toxicants from cigarette smoke.</p

    Eosinophilic granuloma of the cervical spine : A case report and review of the literature

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    This is a report of a case of eosinophilic granuloma involving the second cervical vertebra in a 33-year-old woman. There have been 32 case reports in the literature describing eosinophilic granuloma presenting as cervical spine disease. Due to its intimate relation to the central nervous system, the opportunity for neurological sequelae and neurosurgical intervention is common in cervical eosinophilic granuloma. In this report a brief history of eosinophilic granluoma is reviewed and case histories from the literature with cervical spine involvement are summarized. The therapeutic options are described and a recommended protocol for management is outlined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29531/1/0000618.pd

    Intrinsic monitoring of learning success facilitates memory encoding via the activation of the SN/VTA-Hippocampal loop

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    Humans constantly learn in the absence of explicit rewards. However, the neurobiological mechanisms supporting this type of internally-guided learning (without explicit feedback) are still unclear. Here, participants who completed a task in which no external reward/feedback was provided, exhibited enhanced fMRI-signals within the dopaminergic midbrain, hippocampus, and ventral striatum (the SN/VTA-Hippocampal loop) when successfully grasping the meaning of new-words. Importantly, new-words that were better remembered showed increased activation and enhanced functional connectivity between the midbrain, hippocampus, and ventral striatum. Moreover, enhanced emotion-related physiological measures and subjective pleasantness ratings during encoding were associated with remembered new-words after 24 hr. Furthermore, increased subjective pleasantness ratings were also related to new-words remembered after seven days. These results suggest that intrinsic-potentially reward-related-signals, triggered by self-monitoring of correct performance, can promote the storage of new information into long-term memory through the activation of the SN/VTA-Hippocampal loop, possibly via dopaminergic modulation of the midbrain

    Living with diabetes: rationale, study design and baseline characteristics for an Australian prospective cohort study

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    Background: Diabetes mellitus is a major global public health threat. In Australia, as elsewhere, it is responsible for a sizeable portion of the overall burden of disease, and significant costs. The psychological and social impact of diabetes on individuals with the disease can be severe, and if not adequately addressed, can lead to the worsening of the overall disease picture. The Living With Diabetes Study aims to contribute to a holistic understanding of the psychological and social aspects of diabetes mellitus

    A sensorimotor control framework for understanding emotional communication and regulation

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    JHGW and CFH are supported by the Northwood Trust. TEVR was supported by a National Health and Medical Research Council (NHMRC) Early Career Fellowship (1088785). RP and MW were supported by the the Australian Research Council (ARC) Centre of Excellence for Cognition and its Disorders (CE110001021)Peer reviewedPublisher PD

    ECMO for COVID-19 patients in Europe and Israel

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    Since March 15th, 2020, 177 centres from Europe and Israel have joined the study, routinely reporting on the ECMO support they provide to COVID-19 patients. The mean annual number of cases treated with ECMO in the participating centres before the pandemic (2019) was 55. The number of COVID-19 patients has increased rapidly each week reaching 1531 treated patients as of September 14th. The greatest number of cases has been reported from France (n = 385), UK (n = 193), Germany (n = 176), Spain (n = 166), and Italy (n = 136) .The mean age of treated patients was 52.6 years (range 16–80), 79% were male. The ECMO configuration used was VV in 91% of cases, VA in 5% and other in 4%. The mean PaO2 before ECMO implantation was 65 mmHg. The mean duration of ECMO support thus far has been 18 days and the mean ICU length of stay of these patients was 33 days. As of the 14th September, overall 841 patients have been weaned from ECMO support, 601 died during ECMO support, 71 died after withdrawal of ECMO, 79 are still receiving ECMO support and for 10 patients status n.a. . Our preliminary data suggest that patients placed on ECMO with severe refractory respiratory or cardiac failure secondary to COVID-19 have a reasonable (55%) chance of survival. Further extensive data analysis is expected to provide invaluable information on the demographics, severity of illness, indications and different ECMO management strategies in these patients
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