16 research outputs found

    Transesterification Reaction of Palm Kernel Oil (PKO) on a Bed of Crushed Cashew Nut Shell (CCNS)

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    Biodiesel (GA1) was produced by the transesterification reaction of palm kernel oil (PKO) and methanol catalysed by crushed cashew nut shaft. Biodiesel samples GA2 – GA4 were also produced from the palm kernel oil using conventional base catalysis by NaOH and crushed cashew nut shaft combined with NaOH. The physico-chemical properties and spectroscopic data of the four samples were found to be similar and compared favourably to those of standard biodiesel. Keywords: Transesterification, palm kernel oil, cashew nut shell, methanolysis, biodiesel

    Cosmological parameters from Galaxy Clusters: an Introduction

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    This lecture is an introduction to cosmological tests with clusters of galaxies. Here I do not intend to provide a complete review of the subject, but rather to describe the basic procedures to set up the fitting machinery to constrain cosmological parameters from clusters, and to show how to handle data with a critical insight. I will focus mainly on the properties of X-ray clusters of galaxies, showing their success as cosmological tools, to end up discussing the complex thermodynamics of the diffuse intracluster medium and its impact on the cosmological tests.Comment: 32 pages, 16 figures, conference proceedings for the 3rd Aegean Summer School, Chios, 26 September - 1 October, 200

    Cosmology with clusters of galaxies

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    In this Chapter I review the role that galaxy clusters play as tools to constrain cosmological parameters. I will concentrate mostly on the application of the mass function of galaxy clusters, while other methods, such as that based on the baryon fraction, are covered by other Chapters of the book. Since most of the cosmological applications of galaxy clusters rely on precise measurements of their masses, a substantial part of my Lectures concentrates on the different methods that have been applied so far to weight galaxy clusters. I provide in Section 2 a short introduction to the basics of cosmic structure formation. In Section 3 I describe the Press--Schechter (PS) formalism to derive the cosmological mass function, then discussing extensions of the PS approach and the most recent calibrations from N--body simulations. In Section 4 I review the methods to build samples of galaxy clusters at different wavelengths. Section 5 is devoted to the discussion of different methods to derive cluster masses. In Section 6 I describe the cosmological constraints, which have been obtained so far by tracing the cluster mass function with a variety of methods. Finally, I describe in Section 7 the future perspectives for cosmology with galaxy clusters and the challenges for clusters to keep playing an important role in the era of precision cosmology.Comment: 49 pages, 19 figures, Lectures for 2005 Guillermo Haro Summer School on Clusters, to appear in "Lecture notes in Physics" (Springer

    Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

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    Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

    Optimizing Pharmacology Studies in Pregnant and Lactating Women Using Lessons from HIV: A Consensus Statement

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    Information on the extent of drug exposure to mothers and infants during pregnancy and lactation normally becomes available years after regulatory approval of a drug. Clinicians face knowledge gaps on drug selection and dosing in pregnancy and infant exposure during breastfeeding. Physiological changes during pregnancy often result in lower drug exposures of antiretrovirals, and in some cases a risk of reduced virologic efficacy. The International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) network and the World Health Organization (WHO)–convened Pediatric Antiretrovirals Working Group collaboratively organized a workshop of key stakeholders in June 2019 to define key standards to generate pharmacology data for antiretrovirals to be used among pregnant and lactating women; review the antiretroviral product pipeline; describe key gaps for use in low-income and middle-income countries; and identify opportunities to undertake optimal studies allowing for rapid implementation in the clinical field. We discussed ethical and regulatory principles, systemic approaches to obtaining data for pregnancy pharmacokinetic/pharmacodynamic (PK/PD) studies, control groups, optimal sampling times during pregnancy, and pharmacokinetic parameters to be considered as primary end points in pregnancy PK/PD studies. For lactation studies, the type of milk to collect, ascertainment of maternal adherence, and optimal PK methods to estimate exposure were discussed. Participants strongly recommended completion of preclinical reproductive toxicology studies prior to phase III, to allow study protocols to include pregnant women or to allow women who become pregnant after enrolment to continue in the trial. The meeting concluded by developing an algorithm for design and interpretation of results and noted that recruitment of pregnant and lactating women into clinical trials is critical

    Mechanically-induced solvent-less synthesis of cobalt and nickel complexes of cimetidine

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    Solvent-less synthesis of [Co(CIM)2](SO4) and [Ni(CIM)2](OAC)2 by grinding of CoSO4 and Ni(CH3COO)2.4H2O with cimetidine without any solvent is described. The complexes have been characterized by elemental analysis, melting point, AAS, conductivity measurements, TLC, infrared and UV-Vis spectroscopies as well as X-ray powder diffraction. Cimetidine was found to be bidentate or tridentate ligand. Cobalt ion coordinate with cimetidine through the sulphur atom in the thiol group, nitrogen atom of imidazole ring and the nitrogen atom of the secondary amine to give an octahedral geometry with ligand acting as tridentate whereas nickel ion coordinates through the sulphur atom in the thiol group, nitrogen atom of imidazole ring to give tetrahedral structure with ligand acting as bidentate. X-Ray diffraction patterns of the complex were different from that of the ligand suggesting formation of coordination compounds. The method is quick and gives a quantatively yield, without the need for solvents or external heating. Clearly, it can present higher efficiency in terms of materials, energy and time compared to classical solution phase synthesis
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