The present paper describes the use of experimental designs (DoE) in association with high throughput experimentation devices for the optimization of cobalt hydroformylation of olefins in a biphasic ...system using ionic liquids. The main goal of the study was to gain insight into the various factors (CoNAIL, L/Co, Phorg/PhNAIL, pressure and temperature) and how they interact and influence the activity and selec-tivity of the catalyst. On the basis of a D-Optimal design, the study pointed out that temperature and to a less extend “Phaseorga/PhaseNAIL” ratio are the most critical parameters. These conclusions confirm to a certain extend, the initial hypothesis formulated to describe the process operation. Furthermore, this strategy in association with high throughput experimentation devices, allows to predict catalytic results in the major part of a cubic space (representing the experimental domain) giving us the opportunity to determine the most suitable catalysts composition and optimal reaction conditions. Ce document décrit l’utilisation des plans d’expériences en association avec des équipements d’expérimentation haut débit, pour le développement et l’optimisation de la réaction d’hydroformylation des oléfines par le cobalt en milieu liquide ionique. L’objectif principal de ce travail était d’identifier la manière dont les différents paramètres de réaction (CoLi, L/Co, Phorg/PhNAIL, pression et température) interagissent les uns avec les autres et d’évaluer leur influence sur l’activité et la sélectivité du catalyseur. Sur la base d’un plan d’expériences D-Optimal, cette étude fait ressortir la température et dans une moindre mesure le ratio “Phaseorga/PhaseNAIL” comme étant les paramètres critiques du procédé. Ces conclusions confirment dans une certaine mesure, les hypothèses formulées initialement pour décrire le principe de fonctionnement du procédé mis en oeuvre. Cette stratégie permet de prédire rapidement les performances du système dans l’ensemble du domaine expérimental avec la possibilité d’identifier un optimum de fonctionnement.
To evaluate whether the addition of 2 weeks of ranitidine to a 1-week oral triple therapy (OTT) regimen improved ulcer healing and H. pylori eradication.
Two hundred and eleven consecutive patients ...with an endoscopic diagnosis of active duodenal ulcer (DU) and a positive antrum biopsy for H. pylori were enrolled. Those attending the Hospital Vera Cruz (Group A, n=142) received a 14-day course of ranitidine (150 mg after breakfast and dinner) plus a 1-week OTT, consisting of bismuth subcitrate, (240 mg after the 3 meals), tetracycline (500 mg, 10 min before the three meals and at bedtime), and furazolidone (200 mg after breakfast and dinner). Patients from the Hospital das Clinicas (Group B, n=69) received the same OTT as Group A but without ranitidine. Patients underwent endoscopy again on average 40 days (range: 30-60 days) after completing therapy in order to assess ulcer healing and H. pylori status.
Both schedules were equally efficient in eradicating H. pylori with 90% (128/142) eradication in group A, and 84% (58/69) in group B (p=0.2). In contrast, the addition of ranitidine to OTT improved ulcer healing when compared with OTT alone (96%, 137/142, vs. 70%, 48/69; p<0.001).
Our results demonstrate that the association of acid suppression, obtained with 2 week ranitidine administration with OTT improved ulcer healing but did not enhance H. pylori eradication.
We present the validation of a recent fractional mathematical model for erythrocyte sedimentation proposed by Sharma et al. \cite{GMR}. The model uses a Caputo fractional derivative to build a time ...fractional diffusion equation suitable to predict blood sedimentation rates. This validation was carried out by means of erythrocyte sedimentation tests in laboratory. Data on sedimentation rates (percentages) were analyzed and compared with the analytical solution of the time fractional diffusion equation. The behavior of the analytical solution related to each blood sample sedimentation data was described and analyzed.
•DFT calculations for epitaxial graphene that grows on unreconstructed and reconstructed SiC(000−1) surfaces.•Structural and electronic inhomogeneity for graphene grown on different types of ...SiC(000−1) surfaces.•Presence of Dirac bands for the first graphitic layer only on top of the reconstructed surfaces.•Ambipolar doping.
The graphitization of the SiC(0001¯) plane, commonly referred to as the C-face of SiC, takes place through the sublimation and reorganization of surface atoms upon high-temperature annealing. Often, such reorganization gives rise to ordered atomic reconstructions over the ideally flat (0001¯) plane. In this article, we use the density functional theory to model graphene/SiC(0001¯) interfaces with an (1×1), (2×2) and (3×3) SiC periodicity. Our results indicate that the interface geometry can be crucial for both the stability and the electronic characteristics of the first graphitic layer, revealing a complex scenario of binding, doping and electronic correlations. We argue that the presence of more than one interface geometry at different areas of the same sample could be a reason for structural inhomogeneity and n- to p-type transitions.
Graves' disease (GD) is an autoimmune thyroid disorder which is associated with the human leucocyte antigens HLA-DR3 and DQA1* O501 in Caucasians. We have explored the possibility that some patients ...with certain HLA specificities develop anti-HLA antibodies which are correlated with environmental factors that may contribute to the development of GD. We studied 40 GD patients and 157 healthy individuals (controls). Serology was used to type HLA-A, -B, -Cw, and -DR antigens. The frequencies of these antigens in relation to lymphocytotoxic anti-HLA-A-B-Cw-DR antibodies and two environmental factors (Yersinia enterocolitica and Coxsackie B virus) were determined. The frequencies of HLA-B15, -B21 and DR3 antigens were increased, whereas HLA-DR5 antigen was decreased in GD patients. A significant association between HLA-DR3 antigen and lymphocytotoxic antibodies was observed, i. e., IgGs from GD patients were cytotoxic to HLA-DR3+ normal B cells. Following absorption with Yersinia enterocolitica or Coxsackie-B-virus, only Coxsackie-B virus completely inhibited the lymphocytotoxic reactions against HLA-DR3+ B cells. Besides confirming the association of HLA-DR3 with GD, this study also suggests the role of Coxsackie-reative HLA-DR3 antibodies as contributing factors to the pathogenesis of the disease.
The aim of this study was to assess bone mineral density and vitamin D metabolism in patients on chronic anticonvulsant therapy.
Sixty-nine men, outpatients on chronic anticonvulsant therapy, who had ...been treated for at least 5 years, were studied, comparing them to thirty healthy controls. Bone mineral density was measured as well as serum levels of calcium, ionized calcium, alkaline phosphatase, PTH, 25-hydroxycholecalciferol and 1, 25-dihydroxycholecalciferol.
No differences in bone mineral density, serum levels of vitamin D and intact-PTH were observed between patients and controls. Bone mineral density was not associated with chronic anticonvulsant therapy.
Those adult patients who were on chronic anticonvulsant therapy and who lived in low latitude regions had normal bone mineral density as well as vitamin D serum levels.
Chromium(III) complexes bearing R'N(CH2PR2)2 (PCNCP) ligands were prepared. Upon activation with methylaluminoxane, these complexes proved to be effective in the selective tri- and tetramerization of ...ethylene. The formation of either 1-hexene or 1-octene was found to be highly dependent on the steric bulk of the substituents R on the phosphine moieties. This observation was rationalized using density functional theory calculations on selected steps of the metallacyclic mechanism of the ethylene oligomerization reaction.
Growth of single crystal 3C-SiC films on large area off-axis (111) Si substrate by chemical vapour deposition technique is here reported. The growth was conducted on off-axis Si substrates due to the ...ability of the misorientation to reduce anti-phase disorder in the 3C-SiC film. 3C-SiC films show an extremely flat surface and interface, stimulating further interest for electrical and mechanical device applications even if a very strong bow, due to the strain induced by the growth process, is observed. Film quality was proved to be high by several investigation techniques and a study of the crystalline defects is also presented. Optical profilometer measurements were also conducted to evaluate accurately the asymmetric curvature of the whole system.
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