62 research outputs found

    Identification of active sites on supported metal catalysts with carbon nanotube hydrogen highways

    Get PDF
    Catalysts consisting of metal particles supported on reducible oxides exhibit promising activity and selectivity for a variety of current and emerging industrial processes. Enhanced catalytic activity can arise from direct contact between the support and the metal or from metal-induced promoter effects on the oxide. Discovering the source of enhanced catalytic activity and selectivity is challenging, with conflicting arguments often presented based on indirect evidence. Here, we separate the metal from the support by a controlled distance while maintaining the ability to promote defects via the use of carbon nanotube hydrogen highways. As illustrative cases, we use this approach to show that the selective transformation of furfural to methylfuran over Pd/TiO2 occurs at the Pd-TiO2 interface while anisole conversion to phenol and cresol over Cu/TiO2 is facilitated by exposed Ti3+ cations on the support. This approach can be used to clarify many conflicting arguments in the literatureWe acknowledge financial support from the National Science Foundation, Grant CAREER1653935. Use of the Advanced Photon Source is supported by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences, under Contract DE-AC02-06CH11357. MRCAT operations are supported by the Department of Energy and the MRCAT member institutions. E.C.W. and J.T.M. were supported in part by Center for Innovative Transformation of Alkane Resources (CISTAR) by the National Science Foundation under Cooperative Agreement No. EEC-1647722. Open access fees fees for this article provided whole or in part by OU Libraries Open Access Fund.Ye

    Differences and Commonalities in Physical, Chemical and Mineralogical Properties of Zanzibari Geophagic Soils

    Get PDF
    The function of human geophagy has long been questioned. We sought to test hypotheses concerning its potential physiological effects through analysis of soils and patterns in geophagy behavior. Eleven samples of geophagic soils consumed by pregnant women on Pemba Island, Zanzibar, Tanzania, were characterized according to their color, texture, major element chemistry, trace element chemistry, bulk mineralogy, and clay mineralogy. An epidemiological study (N = 2367) and ethnographic interviews (N = 57) on Pemba yielded information about geophagic behaviors and socio-demographic and biological characteristics of those who consumed earth. The soils varied widely in color, ranging from light red to white through various shades of brown and yellow, and texture ranged from clay to sand. Major element chemistry of the soils also varied greatly; most were low in Fe and Ca. Trace elements, whether of biological or non-biological significance, were uniformly low when compared with normal ranges of mineral soils. The sole commonality among the samples is that all clay fractions were dominated by a kaolin mineral: kaolinite, halloysite, or a mixture of both. Geophagy behavior also varied greatly, with one major exception: a greater proportion of pregnant women (7.1%) and young children (4.5%) consumed earth than non-pregnant women (0.2%) or men (0%). The presence of kaolin mineral in all samples, its palliative and detoxifying properties, and the highest prevalence of geophagy among those most biologically vulnerable suggest that geophagy may be a protective behavior

    Determination of neo- and d-chiro-Inositol Hexakisphosphate in Soils by Solution 31P NMR Spectroscopy

    Get PDF
    The inositol phosphates are an abundant but poorly understood group of organic phosphorus compounds found widely in the environment. Four stereoisomers of inositol hexakisphosphate (IP6) occur, although for three of these (scyllo, flea, and D-chiro) the origins, dynamics, and biological function remain unknown, due in large part to analytical limitations in their measurement in environmental samples. We synthesized authentic neo- and n-chiro-IP6 and used them to identify signals from these compounds in three soils from the Falkland Islands. Both compounds resisted hypobromite oxidation and gave quantifiable P-31 NMR signals at delta = 6.67 ppm (equatorial phosphate groups of the 4-equatorial/2-axial conformer of neo-IP6) and delta = 6.48 ppm (equatorial phosphate groups of the 2-equatorial/4-axial conformer of D-chiro-IP6) in soil extracts. Inositol hexakisphosphate accounted for 46-54% of the soil organic phosphorus, of which the four stereoisomers constituted, on average, 55.9% (myo), 32.8% (scyllo), 6.1% (neo), and 5.2% (n-chiro). Reappraisal of the literature based on the new signal assignments revealed that neo- and D-chiro-IP6 occur widely in both terrestrial and aquatic ecosystems. These results confirm that the inositol phosphates can constitute a considerable fraction of the organic phosphorus in soils and reveal the prevalence of neo- and D-chiro-IP6 in the environment. The hypobromite oxidation and solution P-31 NMR spectroscopy procedure allows the simultaneous quantification of all four IP6 stereoisomers in environmental samples and provides a platform for research into the origins and ecological significance of these enigmatic compounds

    May Measurement Month 2018: a pragmatic global screening campaign to raise awareness of blood pressure by the International Society of Hypertension

    Get PDF
    Aims Raised blood pressure (BP) is the biggest contributor to mortality and disease burden worldwide and fewer than half of those with hypertension are aware of it. May Measurement Month (MMM) is a global campaign set up in 2017, to raise awareness of high BP and as a pragmatic solution to a lack of formal screening worldwide. The 2018 campaign was expanded, aiming to include more participants and countries. Methods and results Eighty-nine countries participated in MMM 2018. Volunteers (≥18 years) were recruited through opportunistic sampling at a variety of screening sites. Each participant had three BP measurements and completed a questionnaire on demographic, lifestyle, and environmental factors. Hypertension was defined as a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, or taking antihypertensive medication. In total, 74.9% of screenees provided three BP readings. Multiple imputation using chained equations was used to impute missing readings. 1 504 963 individuals (mean age 45.3 years; 52.4% female) were screened. After multiple imputation, 502 079 (33.4%) individuals had hypertension, of whom 59.5% were aware of their diagnosis and 55.3% were taking antihypertensive medication. Of those on medication, 60.0% were controlled and of all hypertensives, 33.2% were controlled. We detected 224 285 individuals with untreated hypertension and 111 214 individuals with inadequately treated (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) hypertension. Conclusion May Measurement Month expanded significantly compared with 2017, including more participants in more countries. The campaign identified over 335 000 adults with untreated or inadequately treated hypertension. In the absence of systematic screening programmes, MMM was effective at raising awareness at least among these individuals at risk

    May measurement month 2018: a pragmatic global screening campaign to raise awareness of blood pressure by the International Society of Hypertension (vol 40, pg 2006, 2019)

    Get PDF

    The Helicobacter pylori Genome Project : insights into H. pylori population structure from analysis of a worldwide collection of complete genomes

    Get PDF
    Helicobacter pylori, a dominant member of the gastric microbiota, shares co-evolutionary history with humans. This has led to the development of genetically distinct H. pylori subpopulations associated with the geographic origin of the host and with differential gastric disease risk. Here, we provide insights into H. pylori population structure as a part of the Helicobacter pylori Genome Project (HpGP), a multi-disciplinary initiative aimed at elucidating H. pylori pathogenesis and identifying new therapeutic targets. We collected 1011 well-characterized clinical strains from 50 countries and generated high-quality genome sequences. We analysed core genome diversity and population structure of the HpGP dataset and 255 worldwide reference genomes to outline the ancestral contribution to Eurasian, African, and American populations. We found evidence of substantial contribution of population hpNorthAsia and subpopulation hspUral in Northern European H. pylori. The genomes of H. pylori isolated from northern and southern Indigenous Americans differed in that bacteria isolated in northern Indigenous communities were more similar to North Asian H. pylori while the southern had higher relatedness to hpEastAsia. Notably, we also found a highly clonal yet geographically dispersed North American subpopulation, which is negative for the cag pathogenicity island, and present in 7% of sequenced US genomes. We expect the HpGP dataset and the corresponding strains to become a major asset for H. pylori genomics

    Slurry Tank Conditioning of Oil Sands: Tailings Behaviour

    No full text
    Slurry tank conditioning as an oil sands process step prior to extraction can be expected to produce a tailings material significantly different from conventional Clark hot water process tailings. Recycle water pond design and operation will depend upon the settling and consolidation properties of the fine tailings stream, and these properties in turn depend upon the chemical and physical conditions to which the oil sands are exposed in the extraction process. Slurry tank conditioning occurs at 50°C and without the addition of any process aides. The release of bitumen from the sand matrix is accomplished using mechanical agitation (stirring) in a tank, prior to desanding and flotation using conventional oil sands separation processes. This is in contrast to the Clark process which conditions the oil sand using tumblers, heat (80°C), and an alkaline water chemistry. The alkaline water chemistry serves to disperse the fine clays, as well as enhance the release of natural surfactants in the bitumen. Both of these effects result in rapid release of bitumen from the sand, allowing for very short residence times (5 to 10 min) in the tumblers. The non-alkanine water chemistry, and (longer residence time) mechanical conditioning in the slurry tank process results in a reduction in dispersion of the fine clays, as well as an increase in the flocculation and settling rate, compared to the Clark process tailings. The rapid flocculation and settling of the fine clays results in a fine tailings stream that begins settling without any induction time and that has a solids free release water. The slurry tank process tailings have an order of magnitude higher permeability than Clark hot water process tailings and they have a significantly improved capacity to support a sand surcharge which will provide a stress to further enhance dewatering, relative to the Clark tailings. The improved capacity to support a sand surcharge indicates that a lower calcium addition would be needed to create CT (relative to Clark tailings). Because of the similar water chemistry, slurry tank and OSLO tailings behaviour will be similar, with the additional potential benefit of tailoring the degree of mechanical conditioning in the slurry tank to maximize bitumen recovery, but minimize clay dispersion. The beneficial fine tailings properties result from both the water chemistry, as well as the more controlled mechanica! conditioning in the slurry tank. Depending upon the connate water chemistry of the oil sands, maintaining a non-alkaline environment after many years of recycle may require chemical treatment of the recycled water. For the lease 13 oil sands tested here, chemical treatment is not likely to he required to control the water chemistry. Toxicity of the release water is significantly lower for the slurry tank conditioned oil sands than for the Clark tailings, although it has some level of toxicity. This means that in any treat and release scenario, the slurry tank conditioned tailings will require less treatment than conventional Clark tailings

    Neuroprotective Properties of NMDA R1 Antagonist (Ketamine) in Cyanide Treated Neurons in vitro

    No full text
    Aims: This study aims at investigating possible means of reducing cyanide toxicity by blocking NMDA R1 via ketamine (an NMDA R1 antagonist). This is to provide a template for quick arrest of cyanide toxicity in neurons under oxygen deprived condition. Place and Duration of Study: Bingham University, Department of Anatomy, Karu, Nigeria. The duration of the study was100 minutes. Methodology: Freshly harvested cortical tissue blocks were perfused in accessory cerebrospinal fluid (ACSF) containing all the necessary salts and glucose. The cultures were treated with ACSF (Control), ACSF+KCN (potassium cyanide), ACSF+KCN+Ketamine and ACSF+Ketamine for a total duration of 100 minutes at 37ºC. Results: The Ketamine had a protective and reversal effects on the tissues both for oxygen deprivation and cyanide toxicity, The cells in tissues treated with ACSF+KCN+Ketamine showed normal appearance of cell body and axonal projections, the cells treated with ACSF+Ketamine showed fewer degenerating cells compared to those treated with cyanide. Conclusion: Ketamine, an NMDA R1 antagonist is neuroprotective against the toxicity of cyanid
    corecore