1,982 research outputs found

    Determination of solid mass fraction in partially frozen hydrocarbon fuels

    Get PDF
    Filtration procedures alone are insufficient to determine the amounts of crystalline solid in a partially frozen hydrocarbon distillate fraction. This is due to the nature of the solidification process by which a large amount of liquid becomes entrapped within an interconnected crystalline structure. A technique has been developed to supplement filtration methods with an independent determination of the amount of liquid in the precipitate thereby revealing the actual value of mass percent crystalline solid, %S. A non-crystallizing dye is injected into the fuel and used as a tracer during the filtration. The relative concentrations of the dye in the filtrate and precipitate fractions is subsequently detected by a spectrophotometric comparison. The filtration apparatus was assembled so that the temperature of the sample is recorded immediately above the filter. Also, a second method of calculation has been established which allows significant reduction in test time while retaining acceptable accuracy of results. Data have been obtained for eight different kerosene range hydrocarbon fuels

    Impurity occurrence and removal in crystalline products from process reactions

    Get PDF
    The behavior of impurities when subjected to crystallizations, and related processes such as recrystallization and reslurrying, has been reviewed with a particular focus on the years 2000ā€“2015, but also including significant cases from outside that period. Small molecule pharmaceuticals and similar small organic molecules are included but not biomolecules, inorganics, or minerals. Phase impurities are only covered when a phase transformation is involved with the management of an impurity. Introductory examples illustrating some general features of crystallization as a method of purification are presented, as well as approaches to quantifying the effectiveness of purification. The review classifies cases based on the behavior of the specific impurities covered. The classes of behavior observed are the removal by washing, recrystallization, or reslurrying (Class I), impurities not being removed by these operations (Class II), and impurities which are removed in conjunction with a phase transformation (Class III). Examples of each of these types of behavior are presented, with many processes producing impurities which fall into more than one of these classes. Studies on the inclusion of extraneous molecules into crystalline materials are also covered. These particularly include the incorporation of compounds as solid solutions, but also eutectic formation and inclusion at surfaces during crystal growth. The relationship between types of impurities and behavior during processing is also examined

    Expanding Disease Definitions in Guidelines and Expert Panel Ties to Industry:A Cross-sectional Study of Common Conditions in the United States

    Get PDF
    BACKGROUND: Financial ties between health professionals and industry may unduly influence professional judgments and some researchers have suggested that widening disease definitions may be one driver of over-diagnosis, bringing potentially unnecessary labeling and harm. We aimed to identify guidelines in which disease definitions were changed, to assess whether any proposed changes would increase the numbers of individuals considered to have the disease, whether potential harms of expanding disease definitions were investigated, and the extent of members' industry ties. METHODS AND FINDINGS: We undertook a cross-sectional study of the most recent publication between 2000 and 2013 from national and international guideline panels making decisions about definitions or diagnostic criteria for common conditions in the United States. We assessed whether proposed changes widened or narrowed disease definitions, rationales offered, mention of potential harms of those changes, and the nature and extent of disclosed ties between members and pharmaceutical or device companies. Of 16 publications on 14 common conditions, ten proposed changes widening and one narrowing definitions. For five, impact was unclear. Widening fell into three categories: creating ā€œpre-diseaseā€; lowering diagnostic thresholds; and proposing earlier or different diagnostic methods. Rationales included standardising diagnostic criteria and new evidence about risks for people previously considered to not have the disease. No publication included rigorous assessment of potential harms of proposed changes. Among 14 panels with disclosures, the average proportion of members with industry ties was 75%. Twelve were chaired by people with ties. For members with ties, the median number of companies to which they had ties was seven. Companies with ties to the highest proportions of members were active in the relevant therapeutic area. Limitations arise from reliance on only disclosed ties, and exclusion of conditions too broad to enable analysis of single panel publications. CONCLUSIONS: For the common conditions studied, a majority of panels proposed changes to disease definitions that increased the number of individuals considered to have the disease, none reported rigorous assessment of potential harms of that widening, and most had a majority of members disclosing financial ties to pharmaceutical companies. Please see later in the article for the Editors' Summar

    Sources of total, non-milk extrinsic, and intrinsic and milk sugars in the diets of older adults living in sheltered accommodation

    Get PDF
    The WHO recommends limiting non-milk extrinsic sugars (NMES) consumption to ā‰¤ 10 % energy to reduce the risk of unhealthy weight gain and dental caries, and to restrict frequency of intake to ā‰¤ 4 times/d to reduce risk of dental caries. Older adults, especially those from low-income backgrounds, are at increased risk of dental caries, yet there is little information on sugars intake (frequency of intake and food sources) in this age group. The aim of this report is to present baseline data from a community-based dietary intervention study of older adults from socially deprived areas of North East England, on the quantity and sources of total sugars, NMES, and intrinsic and milk sugars, and on frequency of NMES intake. Dietary intake was assessed using two 3-d estimated food diaries, completed by 201 participants (170 female, thirty-one male) aged 65ā€“85 years (mean 76Ā·7 (sd 5Ā·5) years) recruited from sheltered housing schemes. Total sugars represented 19Ā·6 %, NMES 9Ā·3 %, and intrinsic and milk sugars 10Ā·3 % of daily energy intake. Eighty-one (40Ā·3 %) exceeded the NMES intake recommendation. Mean frequency of NMES intake was 3Ā·4 times/d. The fifty-three participants (26Ā·4 %) who exceeded the frequency recommendation ( ā‰¤ 4 times/d) obtained a significantly greater percentage of energy from NMES compared with those participants who met the recommendation. The food groups ā€˜biscuits and cakesā€™ (18Ā·9 %), ā€˜soft drinksā€™ (13Ā·1 %) and ā€˜table sugarā€™ (11Ā·1 %) made the greatest contributions to intakes of NMES. Interventions to reduce NMES intake should focus on limiting quantity and frequency of intake of these food groups

    ā€œYou wouldnā€™t celebrate September 11ā€:Testing online polarisation between opposing ideological camps on YouTube

    Get PDF
    Online communication is increasingly associated with growing polarisation in society. In this research, we test a dual-pathway model of online polarisation via intergroup and intragroup interaction of supporters of opposing ideological camps on YouTube. The interaction occurs over a video parody promoting a campaign to change the date of Australia Day celebrations, a divisive issue entailing contrasting narratives about Australian identity, meanings of Australia Day, and interpretations of colonial history. To capture ideological polarisation, we conducted computerised linguistic analysis of polarised talk in the form of comments and replies (N = 1,027) from supporters and opponents of the campaign. The indicators used to capture polarisation are social identification, position certainty, and psychological distance (as reflected by increased anxiety and hostility). Our results show that most polarisation (in the form of increased hostility) occurs in conditions of expression of outgroup dissent (the intergroup interaction pathway) and the most debated content on the online forum revolves around themes relevant to group identity. In addition to contributing to the understanding of group process in an online context, another key contribution of this research is providing a theory-driven method and blueprint to detect polarisation in social media data

    Foreword

    Get PDF
    Little information exists about the loss of all oneā€™s teeth (edentulism) among older adults in low- and middle-income countries. This study examines the prevalence of edentulism and associated factors among older adults in a cross-sectional study across six such countries. Data from the World Health Organization (WHOā€™s) Study on global AGEing and adult health (SAGE) Wave 1 was used for this study with adults aged 50-plus from China (N = 13,367), Ghana (N = 4724), India (N = 7150), Mexico (N = 2315), Russian Federation (N = 3938) and South Africa (N = 3840). Multivariate regression was used to assess predictors of edentulism. The overall prevalence of edentulism was 11.7% in the six countries, with India, Mexico, and Russia has higher prevalence rates (16.3%ā€“21.7%) than China, Ghana, and South Africa (3.0%ā€“9.0%). In multivariate logistic analysis sociodemographic factors (older age, lower education), chronic conditions (arthritis, asthma), health risk behaviour (former daily tobacco use, inadequate fruits and vegetable consumption) and other health related variables (functional disability and low social cohesion) were associated with edentulism. The national estimates and identified factors associated with edentulism among older adults across the six countries helps to identify areas for further exploration and targets for intervention

    Methyl tetra-O-acetyl-Ī±-d-glucopyranuronate: crystal structure and influence on the crystallisation of the Ī² anomer

    Get PDF
    Methyl tetra-O-acetyl-Ī²-d-glucopyranuronate (1) and methyl tetra-O-acetyl-Ī±-d-glucopyranuronate (3) were isolated as crystalline solids and their crystal structures were obtained. That of the Ī² anomer (1) was the same as that reported by Root et al., while anomer (3) was found to crystallise in the orthorhombic space group P212121 with two independent molecules in the asymmetric unit. No other crystal forms were found for either compound upon recrystallisation from a range of solvents. The Ī± anomer (3) was found to be an impurity in initially precipitated batches of Ī²-anomer (1) in quantities <3%; however, it was possible to remove the Ī± impurity either by recrystallisation or by efficient washing, i.e. the Ī± anomer is not incorporated inside the Ī² anomer crystals. The Ī² anomer (1) was found to grow as prisms or needles elongated in the a crystallographic direction in the absence of the Ī± impurity, while the presence of the Ī± anomer (3) enhanced this elongation

    Crystal polymorphs and transformations of 2-iodo-4-nitroaniline

    Get PDF
    Full crystal structural characterization of three crystal polymorphs of 2-iodo-4-nitroaniline was carried out: the triclinic, orthorhombic, and a new monoclinic form. Powder X-ray diffraction, differential scanning calorimetry, and infrared data on the three of these are reported. Solvent-mediated transformations were observed on the basis of changes in crystal morphology and data from an in situ laser probe. Transformation to the monoclinic form was observed in all cases. [Published as part of a virtual special issue of selected papers presented in celebration of the 40th Anniversary Conference of the British Association for Crystal Growth (BACG), which was held at Wills Hall, Bristol, UK, September 6-8, 2009
    • ā€¦
    corecore