70 research outputs found

    Application of ordinal logistic to pregnancy outcomes

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    This research aimed at modelling a categorial response i.e. pregnancy outcome in terms of some predictors and determine the goodness of fit of the model and thereby proferring useful suggestions and recommendations. Ordinal logistic regression was used as a tool to model the pregnancy outcome(i.e live birth, still birth and abortion) with respect to maternal ages, health status, marital status, literacy level, parity, antenatal care, cesarean section,previous surgery and fetal weight. The data of 100 preganant women were gotten from Ekiti State University Teaching Hospital, Ado Ekiti. The study showed that pregnancy outcomes are greatly affected by antenatal care, previous surgery and fetal weight. The study showed that the estimated odd is 19.2 times in favour of individuals that attended Antenatal (i.e. they are 19 times more likely to have livebirth compared to those who did not attend antenatal care). Keyworks: Pregnancy,ordinal logistic regression, probability, catagorical data.

    Application of ordinal logistic to pregnancy outcomes

    Get PDF
    This research aimed at modelling a categorial response i.e. pregnancy outcome in terms of some predictors and determine the goodness of fit of the model and thereby proferring useful suggestions and recommendations. Ordinal logistic regression was used as a tool to model the pregnancy outcome(i.e live birth, still birth and abortion) with respect to maternal ages, health status, marital status, literacy level, parity, antenatal care, cesarean section,previous surgery and fetal weight. The data of 100 preganant women were gotten from Ekiti State University Teaching Hospital, Ado Ekiti. The study showed that pregnancy outcomes are greatly affected by antenatal care, previous surgery and fetal weight. The study showed that the estimated odd is 19.2 times in favour of individuals that attended Antenatal (i.e. they are 19 times more likely to have livebirth compared to those who did not attend antenatal care). Keyworks: Pregnancy,ordinal logistic regression, probability, catagorical data.

    Magnetic origin of the chemical balance in alloyed Fe-Cr stainless steels: First-principles and Ising model study

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    Iron-chromium is the base material for most of the stainless steel grades. Recently, new insights into the origins of fundamental physical and chemical characteristics of Fe-Cr based alloys have been achieved. Some of the new results are quite unexpected and call for further investigations. The present study focuses on the magnetic contribution in the atomic driving forces related to the chemical composition in Fe-Cr when alloyed with Al, Ti, V, Mn, Co, Ni, and Mo. Using the ab initio exact muffin-tin orbitals method combined with an Ising-type spin model, we demonstrate that the magnetic moment of the solute atoms with the induced changes in the magnetic moments of the host atoms form the main factor in determining the mixing energy and chemical potentials of low-Cr Fe-Cr based alloys. The results obtained in the present work are related to the designing and tuning of the microstructure and corrosion protection of low-Cr steels. (C) 2014 Elsevier B. V. All rights reserved.</p

    Medicinal plants with anti-SARS-CoV activity repurposing for treatment of COVID-19 infection: A systematic review and meta-analysis

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    The novel SARS-CoV-2 (severe acute respiratory syndrome coronavirus) has emerged as a significant threat to public health with startling drawbacks in all sectors globally. This study investigates the practicality of some medicinal plants for SARS-CoV-2 therapy using a systematic review and meta-analysis of their reported SARS-CoV-1 inhibitory potencies. Relevant data were systematically gathered from three databases, viz., Web of Science, PubMed and Scopus. The information obtained included botanical information, extraction method and extracts concentrations, as well as the proposed mechanisms. Fourteen articles describing 30 different plants met our eligibility criteria. Random effects model and subgroup analysis were applied to investigate heterogeneity. According to subgroup analysis, the substantial heterogeneity of the estimated mean based on the IC50 values reporting the most potent anti-SARS-CoV 3C-like protease (3CLpro) inhibitors (10.07 %, p < 0.0001), was significantly higher compared to the most active anti-SARS-CoV papain-like protease (PLpro) inhibitors (6.12 %, p < 0.0001). More importantly, the literature analysis revealed that fruit extracts of Rheum palmatum Linn. and the compound cryptotanshinone isolated from the root of Salvia miltiorrhiza (IC50 = of 0.8 ± 0.2 ”mol L–1) were excellent candidates for anti-SARS-CoV targeting PLpro. Meanwhile, iguesterin (IC50 = 2.6 ± 0.6 ”mol L–1) isolated from the bark of Tripterygium regelii emerged as the most excellent candidate for anti-SARS-CoV targeting 3CLpro. The present systematic review and meta-analysis provide valuable and comprehensive information about potential medicinal plants for SARS-CoV-2 inhibition. The chemotypes identified herein can be adopted as a starting point for developing new drugs to contain the novel virus

    Segregation, precipitation, and \alpha-\alpha' phase separation in Fe-Cr alloys: a multi-scale modelling approach

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    Segregation, precipitation, and phase separation in Fe-Cr systems is investigated. Monte Carlo simulations using semiempirical interatomic potential, first-principles total energy calculations, and experimental spectroscopy are used. In order to obtain a general picture of the relation of the atomic interactions and properties of Fe-Cr alloys in bulk, surface, and interface regions several complementary methods has to be used. Using Exact Muffin-Tin Orbitals method the effective chemical potential as a function of Cr content (0-15 at.% Cr) is calculated for a surface, second atomic layer and bulk. At ~10 at.% Cr in the alloy the reversal of the driving force of a Cr atom to occupy either bulk or surface sites is obtained. The Cr containing surfaces are expected when the Cr content exceeds ~10 at.%. The second atomic layer forms about 0.3 eV barrier for the migration of Cr atoms between bulk and surface atomic layer. To get information on Fe-Cr in larger scales we use semiempirical methods. Using combined Monte Carlo molecular dynamics simulations, based on semiempirical potential, the precipitation of Cr into isolated pockets in bulk Fe-Cr and the upper limit of the solubility of Cr into Fe layers in Fe/Cr layer system is studied. The theoretical predictions are tested using spectroscopic measurements. Hard X-ray photoelectron spectroscopy and Auger electron spectroscopy investigations were carried out to explore Cr segregation and precipitation in Fe/Cr double layer and Fe_0.95Cr_0.05 and Fe_0.85Cr_0.15 alloys. Initial oxidation of Fe-Cr was investigated experimentally at 10^-8 Torr pressure of the spectrometers showing intense Cr_2O_3 signal. Cr segregation and the formation of Cr rich precipitates were traced by analysing the experimental spectral intensities with respect to annealing time, Cr content, and kinetic energy of the exited electron.Comment: 16 pages, 14 figures, 52 reference

    Alloy Steel: Properties and Use First-Principles Quantum Mechanical Approach to Stainless Steel Alloys

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    Accurate description of materials requires the most advanced atomic-scale techniques from both experimental and theoretical areas. In spite of the vast number of available techniques, however, the experimental study of the atomic-scale properties and phenomena even in simple solids is rather difficult. In steels the challenges become more complex due to the interplay between the structural, chemical and magnetic effects. On the other hand, advanced computational methods based on density functional theory ensure a proper platform for studying the fundamental properties of steel materials from first-principles. In 1980’s the first-principles description of the thermodynamic properties of elemental iron was still on the borderline of atomistic simulations. Today the numerous application- oriented activities at the industrial and academic sectors are paired by a rapidly increasing scientific interest. This is reflected by the number of publications on ab initio steel research, which has increased from null to about one thousand within the last two decades. Our research group has a well established position in developing and applying computational codes for steel related applications. Using our ab initio tools, we have presented an insight to the electronic and magnetic structure, and micromechanical properties of austenite and ferrite stainless steel alloys. In the present contribution, we review the most important developments within the ab initio quantum mechanics aided steel design with special emphasis on the role of magnetism on the fundamental properties of alloy steels

    Changes in ocular signs and symptoms in patients switching from bimatoprost–timolol to tafluprost–timolol eye drops: an open-label phase IV study

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    Objectives: Bimatoprost–timolol (bimatoprost 0.03%–timolol 0.5% fixed-dose combination [FDC]) and tafluprost–timolol (tafluprost 0.0015%–timolol 0.5% FDC) eye drops are currently the only topical intraocular pressure (IOP)-reducing therapies available as preservative-free (PF) prostaglandin and timolol FDC. The aim of this study was to investigate changes to ocular signs and symptoms when patients with ocular hypertension (OH) or open-angle glaucoma (OAG) switched from PF or benzalkonium chloride (BAK)-preserved bimatoprost–timolol to PF tafluprost–timolol eye drops. Design: This was a 12-week, open-label, phase IV study. Setting: Sixteen centres in Finland, Germany, Italy and the UK. Participants: Patients with OH or OAG (IOP on medication ≀21 mm Hg), treated with PF or BAK-preserved bimatoprost–timolol for ≄4 weeks before screening, and presenting with conjunctival hyperaemia and ≄1 ocular symptom. Interventions: Patients were switched to PF tafluprost–timolol once daily in the treated eye(s). Primary and secondary outcome measures: The primary endpoints were change from screening to week 12 in conjunctival hyperaemia and worst ocular symptom. The secondary outcome measures were changes from screening in ocular signs (other than conjunctival hyperaemia) and symptoms at week 12. Results: Of 123 enrolled patients, 121 were included in the intention-to-treat dataset, of which all were Caucasian and 54.5% were female; 76 patients used BAK-preserved bimatoprost–timolol and 45 used PF drops. Conjunctival hyperaemia and severity of worst ocular symptom following switch to PF tafluprost–timolol significantly reduced from screening to week 12 in all patients (p<0.001). The percentage of patients with ocular signs and symptoms was significantly reduced at week 12 compared with screening (p<0.001). IOP was not affected by the change of treatment. Conclusions: Switching from BAK-preserved or PF bimatoprost–timolol to tafluprost–timolol reduced both signs and symptoms of ocular surface disease with no clinically relevant effect on IOP

    Segregation, precipitation, and α-α' phase separation in Fe-Cr alloys

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    Iron-chromium alloys, the base components of various stainless steel grades, have numerous technologically and scientifically interesting properties. However, these features are not yet sufficiently understood to allow their full exploitation in technological applications. In this work, we investigate segregation, precipitation, and phase separation in Fe-Cr systems analyzing the physical mechanisms behind the observed phenomena. To get a comprehensive picture of Fe-Cr alloys as a function of composition, temperature, and time the present investigation combines Monte Carlo simulations using semiempirical interatomic potential, first-principles total energy calculations, and experimental spectroscopy. In order to obtain a general picture of the relation of the atomic interactions and properties of Fe-Cr alloys in bulk, surface, and interface regions several complementary methods have to be used. Using the exact muffin-tin orbitals method with the coherent potential approximation (CPA-EMTO) the effective chemical potential as a function of Cr content (0–15 at. % Cr) is calculated for a surface, second atomic layer, and bulk. At ∌10 at. % Cr in the alloy the reversal of the driving force of a Cr atom to occupy either bulk or surface sites is obtained. The Cr-containing surfaces are expected when the Cr content exceeds ∌10 at. %. The second atomic layer forms about a 0.3 eV barrier for the migration of Cr atoms between the bulk and surface atomic layer. To get information on Fe-Cr in larger scales we use semiempirical methods. However, for Cr concentration regions less than 10 at. %, the ab initio (CPA-EMTO) result of the important role of the second atomic layer to the surface is not reproducible from the large-scale Monte Carlo molecular dynamics (MCMD) simulation. On the other hand, for the nominal concentration of Cr larger than 10 at. % the MCMDsimulations show the precipitation of Cr into isolated pockets in bulk Fe-Cr and the existence of the upper limit of the solubility of Cr into Fe layers in Fe/Cr layer systems. For high Cr concentration alloys the performed spectroscopic measurements support the MCMD simulations. Hard x-ray photoelectron spectroscopy and Auger electron spectroscopy investigations were carried out to explore Cr segregation and precipitation in the Fe/Cr double layer and Fe0.95Cr0.05 and Fe0.85Cr0.15 alloys. Initial oxidation of Fe-Cr was investigated experimentally at 10−8 Torr pressure of the spectrometers showing intense Cr2O3 signal. Cr segregation and the formation of Cr-rich precipitates were traced by analyzing the experimental atomic concentrations and chemical shifts with respect to annealing time, Cr content, and kinetic energy of the exited electron.</p
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