Aluminum corrosion inhibition by cefixime drug: experimental and DFT studies

Corrosion inhibition of aluminum in 1 M HCl by cefixime drug has been studied at 298-318 K using mass loss, Tafel polarization (at 298 K) and quantum chemical methods based on density functional theory (DFT) calculations. The results showed that inhibition efficiency increases up to 90.41 % with increase of the inhibitor concentration from 0.02 to 2 mM, but decreases with a rise of the solution temperature. Adsorption of cefixime molecules on the corroding aluminum surface obeys Langmuir adsorption isotherm and occurs spontaneously mostly through a physisorption process. The activation energy (Ea) as well as other thermodynamic parameters of the inhibition process are calculated and discussed. Potentiodynamic polarization data revealed that cefixime acts as mixed-type inhibitor and pointed out an agreement with mass loss results. Surface analysis is performed using scanning electron microscopy (SEM) which confirmed existence of a protective film of inhibitor molecules on the aluminum surface. In addition, global and local reactivity parameters of the studied molecule are analyzed and discussed. The computed results are found in agreement with experimental data

What is the impact of a national postgraduate medical specialist education reform on the daily clinical training 3.5 years after implementation? A questionnaire survey

<p>Abstract</p> <p>Background</p> <p>Many countries have recently reformed their postgraduate medical education (PGME). New pedagogic initiatives and blueprints have been introduced to improve quality and effectiveness of the education. Yet it is unknown whether these changes improved the daily clinical training. The purpose was to examine the impact of a national PGME reform on the daily clinical training practice.</p> <p>Methods</p> <p>The Danish reform included change of content and format of specialist education in line with outcome-based education using the CanMEDS framework. We performed a questionnaire survey among all hospital doctors in the North Denmark Region. The questionnaire included items on educational appraisal meetings, individual learning plans, incorporating training issues into work routines, supervision and feedback, and interpersonal acquaintance. Data were collected before start and 31/2 years later. Mean score values were compared, and response variables were analysed by multiple regression to explore the relation between the ratings and seniority, type of hospital, type of specialty, and effect of attendance to courses in learning and teaching among respondents.</p> <p>Results</p> <p>Response rates were 2105/2817 (75%) and 1888/3284 (58%), respectively. We found limited impact on clinical training practice and learning environment. Variances in ratings were hardly affected by type of hospital, whereas belonging to the laboratory specialities compared to other specialties was related to higher ratings concerning all aspects.</p> <p>Conclusions</p> <p>The impact on daily clinical training practice of a national PGME reform was limited after 31/2 years. Future initiatives must focus on changing the pedagogical competences of the doctors participating in daily clinical training and on implementation strategies for changing educational culture.</p

Glacio-meteorological conditions in the vicinity of the Belgian Princess Elisabeth Station: Antarctica

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Impact of Micro-, Mini- and Multi-Electrode Mapping on Ventricular Substrate Characterisation

Accurate substrate characterisation may improve the evolving understanding and treatment of cardiac arrhythmias. During substrate-based ablation techniques, wide practice variations exist with mapping via dedicated multi-electrode catheter or conventional ablation catheters. Recently, newer ablation catheter technology with embedded mapping electrodes have been introduced. This article focuses on the general misconceptions of voltage mapping and more specific differences in unipolar and bipolar signal morphology, field of view, signal-to-noise ratio, mapping capabilities (density and resolution), catheter-specific voltage thresholds and impact of micro-, mini- and multi-electrodes for substrate mapping. Efficiency and cost-effectiveness of different catheter types are discussed. Increasing sampling density with smaller electrodes allows for higher resolution with a greater likelihood to record near-field electrical information. These advances may help to further improve our mechanistic understanding of the correlation between substrate and ventricular tachycardia, as well as macro-reentry arrhythmia in humans.Cardiolog

Antioxidant Activity Of Maté Tea And Effects Of Processing

Maté tea is a popular beverage made from the leaves and stems of the yerba-maté (. Ilex paraguariensis Auguste Saint Hillaire), a plant native to the southern part of South America (Argentina, Brazil, and Paraguay). The commercial products derived from the processing of yerba-maté are used in the preparation of several types of beverages appreciated for their peculiar bitter taste and functional properties (antioxidant, stimulant, diuretic, hypocholesterolemic, and hepatoprotective). The bulk of harvested yerba-maté leaves are used in the preparation of teas (known as maté tea), a partial infusion drink with hot water (. chimarrão), and a total infusion cold drink (. tererê). Important compounds found in maté products are caffeoyl derivatives, methylxanthines, and flavonoids. The conditions for the processing of yerba-maté vary widely, depending on the manufacturer and the desired style and flavor of maté tea, which is reflected in somewhat diverging results on processing effects on bioactive compounds. Nevertheless, processing tends to reduce methylxanthines, such as caffeine, but increases the content of polyphenols, such as the caffeoyl derivatives, resulting in higher antioxidant activity. © 2014 Elsevier Inc. All rights reserved.145153Alonso, J.R., (1998) Tratado de fitomedicina, , Editora Isis, Buenos Aires, Argentina, 992-995Andrade, F., Albuquerque, C.A.C., Maraschin, M., Silva, E.L., Safety assessment of yerba maté (Ilex paraguariensis) dried extract: Results of acute and 90 days subchronic toxicity studies in rats and rabbits (2012) Food Chem. 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Farm (2005) Bonaerense, 24, pp. 91-95Bastos, D.H.M., Fornari, A.C., Queiroz, Y.S., Torres, E.A.F.S., Bioactive compounds content of chimarrão infusions related to the moisture of yerba maté (Ilex paraguariensis) leaves (2006) Braz. Arch. Biol. Technol, 49, pp. 399-404Bastos, D.H.M., Ishimoto, E.Y., Marques, M.O.M., Ferri, A.F., Torres, E.A.F.S., Essential oil and antioxidant activity of green maté and maté tea (Ilex paraguariensis) infusions (2006) J. Food Comp. Anal., 19, pp. 538-543Bastos, D.H.M., Saldanha, L.A., Catharino, R.R., Sawaya, A.C.H.F., Cunha, I.B.S., Carvalho, P.O., Eberlin, M.N., Phenolic antioxidants identified by ESI-MS from yerba-maté (Ilex paraguariensis) and green tea (Camelia sinensis) extracts (2007) Molecules, 12, pp. 423-432Berté, K.A.S., Beux, M.R., Spada, P.K.W.D.S., Salvador, M., Hoffmann-Ribani, R., Chemical composition and antioxidant activity of yerba-maté (Ilex paraguariensis A.St.-Hil., Aquifoliaceae) extract as obtained by spray drying (2011) J. Agric. 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Rapid Commun (1998) Mass Spectrom, 12, pp. 1813-1819Chandra, S., Mejia, E.G., Polyphenolic compounds, antioxidant capacity, and quinone reductase activity of an aqueous extract of Ardisia compressa in comparison to maté (Ilex paraguariensis) and green (Camellia sinensis) teas (2004) J. Agric. Food Chem., 52, pp. 3583-3589Clifford, M.N., Ramirez-Martinez, J.R., Chlorogenic acids and purine alkaloids contents of maté (Ilex paraguariensis) leaf and beverage (1990) Food Chem., 35, pp. 13-21Dartora, N., Souza, L.M., Santana-Filho, A.P., Iacomini, M., Valduga, A.T., Gorin, P.A.J., Sassaki, G.L., UPLC-PDA-MS evaluation of bioactive compounds from leaves of Ilex paraguariensis with different growth conditions, treatments and ageing (2011) Food Chem., 129, pp. 1453-1461Davicino, R., Alonso, R., Anesini, C., Comparison between normal coffee and decaffeinated coffee effects on lymphocytes and macrophages: role of the antioxidant activity of caffeine (2011) J. 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Energy efficiency and renewable energy under extreme conditions: case studies from Antarctica

This article showcases a range of small and large scale energy efficiency and renewable energy deployments at Antarctic research stations and field camps. Due to the cold and harsh environment, significant amounts of fuel are needed to support humans working and living in Antarctica. The purchase, transportation and storage of large amounts of fossil fuel entail significant economic costs and environmental risks and have motivated developments in energy efficiency and renewable energy deployment. Over the past three decades, improved building design, behavioral change, cogeneration, solar collectors, solar panels and wind turbines have been found to be effective in Antarctica, demonstrating that harsh environmental conditions and technological barriers do not have to limit the deployment of energy efficiency and renewable energy. The ambition to run entire stations or field camps on 100% renewable energy is increasingly common and feasible. While the power requirements of Antarctic research stations are small compared to urban installations on other continents, these case studies clearly demonstrate that if energy efficiency and renewable energy can be deployed widely on the coldest, darkest and most remote continent of the world, their deployment should be more widespread and encouraged on other continents

Advertising in a digital media environment (ADME): An interdisciplinary approach to a user-centered advertising model for IDTV

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