3,250 research outputs found
Sustainable Organic Synthesis: Tools and Strategies
No full textOver the last sixty years, organic synthesis has reached a very high level of sophistication leading to the realization of innovative synthetic protocols for the construction of complex molecular architectures. Parallel to these achievements, new issues in today's world, dealing with the concepts of resilience (defined as the capability and ability of an environmental system to return to a stable state after damage/disruption),1 sustainable development2 and, in the case of chemical production, preventing pollution3 have emerged.
Such issues have been levied by ordinary people to the Scientific Society, and institutions such as the International Union of Pure and Applied Chemistry (IUPAC) and the Organization for Economic Co-operation and Development (OECD) to assess the synthetic approaches in order to develop sustainable alternatives and to face this new challenge.
With the aim of spurring scientists and industries on the way to this new research philosophy, the U.S. Environmental Protection Agency, with the impregnable contribution of Paul Anastas and John Warner,4 formalized in 1993 the concept of “Green Chemistry”, as the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances. In this regard, both guidelines (denoted as twelve principles of green chemistry)5 and green metrics, in order to assess and quantify the environmental impact of a chemical process,6 have been introduced and are nowadays commonly used for assessing and optimizing synthetic protocols, as well as for comparing new and old synthetic processes. In the end, this new consciousness has led scientists to explore a variety of different tools to arrive at the common goal of more sustainable chemical production. In this regard, the realization of this handbook was undertaken with the aim of providing readers with an exhaustive overview on Organic Green Synthesis, by covering all of the synthetic strategies that are currently adopted on the way to sustainability, corroborated also by the use of green/energy metrics.
With this purpose, the handbook is composed of three sections, namely Activation of Chemical Substrates Under Sustainable Conditions, Benign Media for Organic Synthesis and Sustainable Approaches in Organic Synthesis. Accordingly, the first section is focused on synthetic strategies that are well-established (including, among others, homogeneous and heterogeneous catalysis and biocatalysis), or have recently emerged (electrochemistry and visible-light photochemistry) in sustainable organic chemistry, while the second part of the handbook is devoted to bioderived and reusable solvents proposed in the literature as a sustainable alternative to VOCs as the reaction media. The aim of the third section is to describe synthetic philosophies that have recently emerged as a way of thinking to perform sustainable production. The last two chapters are finally focused to the contribution of Green Chemistry to Chemical Engineering and Industrial Chemistry. We believe that this contribution will play a key role in furnishing different practical examples to academic and industrial readers, as well as for introducing green chemistry topics to young researchers and as precious help for students.
We would like to thank the researchers that contributed to this handbook and the staff of the Royal Society of Chemistry (in particular Connor Sheppard and Helen Armes) that supported us in this project
A imagem de Alessandro Baricco no Brasil
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Estudos da Tradução, Florianópolis, 2013.Com a intenção de delinear o modo pelo qual o escritor italiano Alessandro Baricco se inseriu no sistema literário brasileiro e os caminhos percorridos pelos seus livros traduzidos, esta dissertação dá voz às experiências tradutórias de seus tradutores. A inserção de Bariccono Brasil tem seu início em 1997, através de uma proposição da Profa. Dra. Roberta Barni à editora Iluminuras da tradução de Oceano Mare. A partir daí, outras sete obras foram publicadas no Brasil, sendo três delas traduzidas por Roberta Barni e as outras quatro por quatro tradutores diferentes. De um lado, considera-se o tradutor como figura principal namediação entre culturas, e, de outro, se analisa a realidade desta figuradentro do sistema literário, sua invisibilidade, seus limites e o exercíciode sua profissão. A pesquisa conta, ainda, com críticas e resenhas referentes ao autor italiano publicadas em jornais consagrados no Brasil, considerando estas como parte constituinte da imagem de Baricco refletida em território nacional. Abstract : Intending to delineate the way the Italian writer Alessandro Baricco has been inserted in the Brazilian literary system and the paths his translated books have followed, this thesis gives voice to the translating experiences of his translators. Baricco's insertion in Brazil began in 1997, through a personal project of Dr. Roberta Barni, with her translation of Oceano Mare. Since then, seven other of his works have been published in Brazil, three of which were translated by Roberta Barni and the other four by four different translators. On the one hand,the translator is considered as the main figure in mediation betweencultures and, on the other, this figure's reality is analyzed within theliterary system: its invisibility, its limits and its professional practice. Criticisms and reviews of this Italian author published in well established Brazilian newspapers are also considered, with the understanding that they are part of Baricco's image reflected here
Driving airway pressure: should we use a static measure to describe a dynamic phenomenon?
No full textAnticoagulation Management and Antithrombin Supplementation Practice during Veno-venous Extracorporeal Membrane Oxygenation: A Worldwide Survey.
No full textWHAT WE ALREADY KNOW ABOUT THIS TOPIC
Managing anticoagulation during veno-venous extracorporeal membrane oxygenation varies around the world among clinical sites. Understanding clinical practice is important when developing multicenter clinical studies.
WHAT THIS ARTICLE TELLS US THAT IS NEW
Based on 273 responses from 50 countries, unfractionated heparin is used in 96.6% of centers, with partial thromboplastin time monitoring in 41.8%, activated clotting time in 30.0%, and anti-factor Xa activity in 22.7% of centers. Antithrombin is monitored in 48.7% of centers and actively repleted in 38.1% centers, mainly in high-income regions and in pediatric patients.
BACKGROUND
There is a lack of consensus on how to manage anticoagulation during veno-venous extracorporeal membrane oxygenation, including antithrombin monitoring and supplementation. The authors' aim was to determine current practice in a large number of extracorporeal membrane oxygenation centers around the world.
METHODS
This was an electronic survey disseminated in 2018 to directors and coordinators of extracorporeal membrane oxygenation centers as well as to extracorporeal membrane oxygenation experts. Participating centers were classified according to some covariates that may affect practice, including 2017 gross national income per capita, primary patient population, and annual extracorporeal membrane oxygenation patient volume.
RESULTS
The authors analyzed 273 unique responses from 50 countries. Systemic anticoagulation was routinely prescribed in 264 (96.7%) centers, with unfractionated heparin being the drug of choice in 255 (96.6%) of them. The preferred method to monitor anticoagulation was activated partial thromboplastin time in 114 (41.8%) centers, activated clotting time in 82 (30.0%) centers, and anti-factor Xa activity in 62 (22.7%) centers. Circulating antithrombin activity was routinely monitored in 133 (48.7%) centers. Antithrombin supplementation was routinely prescribed in 104 (38.1%) centers. At multivariable analyzes, routine antithrombin supplementation was associated with national income, being less likely in lower- than in higher-income countries (odds ratio, 0.099 [95% CI, 0.022 to 0.45]; P = 0.003); with primary patient population being more frequent in mixed (odds ratio, 2.73 [1.23 to 6.0]; P = 0.013) and pediatric-only centers (odds ratio, 6.3 [2.98 to 13.2]; P < 0.001) than in adult-only centers; but not with annual volume of extracorporeal membrane oxygenation cases, being similarly common in smaller and larger centers (odds ratio, 1.00 [0.48 to 2.08]; P = 0.997).
CONCLUSIONS
There is large practice variation among institutions regarding anticoagulation management and antithrombin supplementation during veno-venous extracorporeal membrane oxygenation. The paucity of prospective studies and differences across institutions based on national income and primary patient population may contribute to these findings
Acid Catalyzed Formation of C–C and C–S Bonds via Excited State Proton Transfer
No full textThe behavior of 2-naphthol and 7-bromo-2-naphthol as organic photoacids are exploited in organic synthesis for the preparation of benzyl sulfides (using a trichloroacetimidate derivative as the starting substrate) and polycyclic amines via acid catalyzed condensation of 1,2,3,4-tetrahydroisoquinoline with aldehydes
Which is the most important strain in the pathogenesis of ventilator-induced lung injury: Dynamic or static?
No full textPURPOSE OF REVIEW:
To discuss the relative role of dynamic and static tissue deformation (strain) generated by inflation of tidal volume and application of positive end-expiratory pressure in the pathogenesis of ventilator-induced lung injury.
RECENT FINDINGS:
Cellular, animal and human studies strongly suggest that dynamic strain is more injurious than static strain, at least when total lung capacity is not exceeded. One possible explanation for these findings is pulmonary viscoelasticity. Large and rapid dynamic deformations generate high and unevenly distributed tensions, internal frictions and energy dissipation in the form of heat, posing microstructure at risk for rupture. The most important strategy to protect the lung may thus be limiting the tidal volume. Increasing static strain may add benefit by diminishing inhomogeneities (stress raisers), especially in the already severely injured lung. On the other side, however, it may adversely affect the haemodynamics.
SUMMARY:
Large lung dynamic strain is more harmful than equivalent static strain
La maturità di Alessandro Fei del Barbiere, in bilico tra Maniera e Riforma
No full textThis article studies the mature career of the Florentine painter Alessandro Fei del Barbiere (1537-1592), beginning with the rediscovery of the 'Ascension' altarpiece formerly in the Albizi Chapel in the destroyed church of San Pier Maggiore, Florence. Studying this painting and others recorded in 1584 by the biographer Raffaello Borghini, such as the two altarpieces for Santa Maria delle Grazie and the Madonna dell'Umiltà in Pistoia, the author reconstructs a body of works showing how in the 1580s Fei gradually went beyond the archaic style of his apprenticeship - he had been trained by Ridolfo del Ghirlandaio and Pierfrancesco Foschi, but was also marked by the Maniera of Vasari - evolving towards naturalism in both mimesis and pictorial handling. In Florence, his development partly parallels that of Santi di Tito and his circle, but Fei was also influenced by a probable sojourn during the early part of that decade in Rome, where he could have been inspired by Girolamo Muziano and the painters working for Pope Gregory XIII. Among other proposals, the author suggests that the artist was responsible for decorating the chancel of Fiesole Cathedral (c. 1584-1589), which consisted of an altarpiece, only rarely discussed by scholars, and a cycle of frescoes hitherto attributed to Nicodemo Ferrucci
Tra socialdemocrazie e Perestrojka. Le relazioni internazionali del Pci attraverso le carte di Alessandro Natta
No full textThis essay reconstructs the foreign policy of the Italian Communist Party during the four
years of Alessandro Natta’s secretariat (1984-1988) through largely original archival documentation,
from the Alessandro Natta Fonds of the Historical Archive of the Chamber of
Deputies. Natta’s papers are also cross-referenced with those kept in the PCI Archive at the
Gramsci Foundation. The author analyses the relationship that the PCI establishes with
Gorbachev’s Perestroika, Deng’s China, and European social democracies during the last
years of the Cold War
Metformin-induced lactic acidosis: no one left behind
No full textMetformin is a safe drug when correctly used in properly selected patients. In real life, however, associated lactic acidosis has been repeatedly, although rarely, reported. The term metformin-induced lactic acidosis refers to cases that cannot be explained by any major risk factor other than drug accumulation, usually due to renal failure. Treatment consists of vital function support and drug removal, mainly achieved by renal replacement therapy. Despite dramatic clinical presentation, the prognosis of metformin-induced lactic acidosis is usually surprisingly good
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