275 research outputs found

    Químics catalans al món: Alicia Casitas Montero

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    A ampla defesa e o contraditório na Polícia Militar do Paraná

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    Orientadores: Luiz Rodrigo Larson Carstens e Americo Augusto Nogueira VieiraMonografia(Especializaçao) - Universidade Federal do Paraná,Setor de Ciencias Sociais Aplicadas, Curso de Especializaçao Estrategias em Segurança PublicaResumo: O presente trabalho utilizou-se do método dedutivo, procurando, na pesquisa bibliográfica e na documental, o embasamento teórico concernente aos institutos da ampla defesa e do contraditório na Polícia Militar do Paraná, em face da evolução havida no ordenamento jurídico contemporâneo. A inserção desses princípios e garantias ultrapassaram barreiras, atingindo a legislação dos militares e, em especial, os regulamentos disciplinares, revelando quebra de paradigmas nas instituições militares. Observou-se que, paulatinamente, esses direitos foram absorvidos, influenciando mudanças na legislação e nos regulamentos internos, estabelecendo um tratamento de igualdade aos militares acusados em geral. Constatou-se, igualmente, que os processos em forma de colegiados, quais sejam, o Conselho de Disciplina e o Conselho de Justificação, não estão perfeitamente amoldados aos princípios estabelecidos na Lei Maior, sendo necessária a atualização dessas leis específicas

    Dual cobalt – copper light-driven catalytic reduction of aldehydes and aromatic ketones in aqueous media

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    We present an efficient, general, fast, and robust light-driven methodology based on earth-abundant elements to reduce aryl ketones, and both aryl and aliphatic aldehydes (up to 1400 TON). The catalytic system consists of a robust and well-defined aminopyridyl cobalt complex active for photocatalytic water reduction and the [Cu(bathocuproine)(Xantphos)](PF6) photoredox catalyst. The dual cobalt–copper system uses visible light as the driving-force and H2O and an electron donor (Et3N or iPr2EtN) as the hydride source. The catalytic system operates in aqueous mixtures (80–60% water) with high selectivity towards the reduction of organic substrates (>2000) vs. water reduction, and tolerates O2. High selectivity towards the hydrogenation of aryl ketones is observed in the presence of terminal olefins, aliphatic ketones, and alkynes. Remarkably, the catalytic system also shows unique selectivity for the reduction of acetophenone in the presence of aliphatic aldehydes. The catalytic system provides a simple and convenient method to obtain α,β-deuterated alcohols. Both the observed reactivity and the DFT modelling support a common cobalt hydride intermediate. The DFT modelled energy profile for the [Co–H] nucleophilic attack to acetophenone and water rationalises the competence of [CoII–H] to reduce acetophenone in the presence of water. Mechanistic studies suggest alternative mechanisms depending on the redox potential of the substrate. These results show the potential of the water reduction catalyst [Co(OTf)(Py2Tstacn)](OTf) (1), (Py2Tstacn = 1,4-di(picolyl)-7-(p-toluenesulfonyl)-1,4,7-triazacyclononane, OTf = trifluoromethanesulfonate anion) to develop light-driven selective organic transformations and fine solar chemicals

    Elementary Steps of Iron Catalysis: Exploring the Links between Iron Alkyl and Iron Olefin Complexes for their Relevance in C—H Activation and C—C Bond Formation

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    The alkylation of complexes 2 and 7 with Grignard reagents containing β-hydrogen atoms is a process of considerable relevance for the understanding of C–H activation as well as C–C bond formation mediated by low-valent iron species. Specifically, reaction of 2 with EtMgBr under an ethylene atmosphere affords the bis-ethylene complex 1 which is an active precatalyst for prototype [2+2+2] cycloaddition reactions and a valuable probe for mechanistic studies. This aspect is illustrated by its conversion into the bis-alkyne complex 6 as an unprecedented representation of a cycloaddition catalyst loaded with two substrates molecules. On the other hand, alkylation of 2 with 1 equivalent of cyclohexylmagnesium bromide furnished the unique iron alkyl species 11 with a 14-electron count, which has no less than four β-H atoms but is nevertheless stable at low temperature against β-hydride elimination. In contrast, the exhaustive alkylation of 1 with cyclohexylmagnesium bromide triggers two consecutive C–H activation reactions mediated by a single iron center. The resulting complex has a diene dihydride character in solution (15), whereas its structure in the solid state is more consistent with an η3-allyl iron hydride rendition featuring an additional agostic interaction (14). Finally, the preparation of the cyclopentadienyl iron complex 25 illustrates how an iron-mediated C–H activation cascade can be coaxed to induce a stereoselective C—C bond formation. The structures of all relevant new iron complexes in the solid state are presented

    Prognostic value of the six-second spirometry in patients with chronic obstructive pulmonary disease: A cohort study

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    Background The six-second spirometry has been proposed as an alternative to diagnose airflow limitation, although its prognostic value in patients with chronic obstructive pulmonary disease (COPD) remains unknown. The purpose of this study was to determine the prognostic value of the postbronchodilator forced expiratory volume in 1 second (FEV1)/forced expiratory volume in 6 seconds (FEV6) ratio and FEV6 in COPD patients. Methods and Findings The study population consisted of 2,614 consecutive stable patients with COPD. The patients were monitored for an average period of 4.3 years regarding mortality, hospitalizations by COPD exacerbations, diagnosis of lung cancer, and annual lung function decline. The overall rate of death was 10.7 (95%CI: 8.7–12.7) per 1000 person-years. In addition to male gender, age and comorbidity, FEV6 (hazard ratio [HR]: 0.981, 95%CI: 0.968–0.003) and FEV1/FEV6 quartiles (lowest quartile (<74% pred.): HR 3.558, 95%CI: 1.752–7.224; and second quartile (74–84% pred.): HR 2.599, 95%CI: 1.215–5.561; versus best quartile (>0.89% pred.)) were independently associated with mortality, whereas FEV1 was not retained in the model. 809 patients (30.9%) had at least one hospital admission due to COPD exacerbation. In addition to sex, age, smoking and comorbidity, FEV1 and FEV1/ FEV6 quartiles were independent risk factors of hospitalization. FEV6 was the only spirometric parameter independently related with lung function annual decline, while the FEV6 and FEV1/FEV6 quartiles were independent risk factors for lung cancer Conclusions In a general COPD outpatient population, airflow obstruction assessed by the FEV1/FEV6 is an independent risk factor for both death and hospitalizationThis study is supported by grants from the Instituto de Salud Carlos III, Spain (PI10-00642 and PI13-01512) and from the Comunidad de Madrid, Spain (S2010/BMD-2542)

    para-Selective C-H amidation of simple arenes with nitriles

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    A para-selective C-H amidation of simple arenes with nitriles has been developed. By increasing the amount of arenes, a further meta-selective C-H arylation of the produced amides occurred. Both steric and electronic effects are utilized to control the selectivity, resulting in only para-selective amidation products. The readily available nitriles as amidation reagents instead of amides makes the synthesis of N-arylamides more accessible

    Identification of non-coding genetic variants in samples from hypoxemic respiratory disease patients that affect the transcriptional response to hypoxia

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    A wide range of diseases course with an unbalance between the consumption of oxygen by tissues and its supply. This situation triggers a transcriptional response, mediated by the hypoxia inducible factors (HIFs), that aims to restore oxygen homeostasis. Little is known about the inter-individual variation in this response and its role in the progression of disease. Herein, we sought to identify common genetic variants mapping to hypoxia response elements (HREs) and characterize their effect on transcription. To this end, we constructed a list of genome-wide HIF-binding regions from publicly available experimental datasets and studied the genetic variability in these regions by targeted re-sequencing of genomic samples from 96 chronic obstructive pulmonary disease and 144 obstructive sleep apnea patients. This study identified 14 frequent variants disrupting potential HREs. The analysis of the genomic regions containing these variants by means of reporter assays revealed that variants rs1009329, rs6593210 and rs150921338 impaired the transcriptional response to hypoxia. Finally, using genome editing we confirmed the functional role of rs6593210 in the transcriptional regulation of EGFR. In summary, we found that inter-individual variability in non-coding regions affect the response to hypoxia and could potentially impact on the progression of pulmonary diseases.Ministerio de Ciencia e Innovación (Spanish Ministry of Science and Innovation, MICINN) [SAF2011 24225 to LdelP, SAF2014-53819-R to L.delP., B.J.]; Comunidad Autónoma de Madrid [S2010/BMD-2542 to L.delP., F.G.R., J.A.], Sociedad Española de Neumología y Cirugía Torácica (SEPAR) [34/2013 to LdelP, F.G.R.]; Fondo de Investigación Sanitaria/Instituto de Salud Carlos III [PI13-01512 to F.G.R.]; Fundación Caja Madrid (Beca de Movilidad para Profesores de las Universidades Públicas de Madrid 2011–2012 to L.delP); Canadian Institutes of Health Research (CIHR) [MOP-82875 to W.W.W.]; Natural Sciences and Engineering Research Council of Canada (NSERC) [RGPIN355532-10 to W.W.W.]; National Institutes of Health [1R01GM084875 toW.W.W.]; CSIC (Spanish National Research Council) [JAE-Doc grant-2010 to O.R., in part by the European Social Fund]. Spanish science, technology and innovation contract [University of Castilla-LaMancha-2014 to O.R., in part by the European Social Fund]. Funding for open access charge: MICINN [SAF2011 24225 to L.delP., SAF2014-53819-R to L.delP., B.J.

    Regioselective Access to Sultam Motifs through Cobalt-Catalyzed Annulation of Aryl Sulfonamides and Alkynes using an 8-Aminoquinoline Directing Group

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    The use of cobalt as catalyst in direct C[BOND]H activation protocols as a replacement for more expensive second row transition metals is currently attracting significant attention. Herein we disclose a facile cobalt-catalyzed C[BOND]H functionalization route towards sultam motifs through annulation of easily prepared aryl sulfonamides and alkynes using 8-aminoquinoline as a directing group. The reaction shows broad substrate scope with products obtained in a highly regioselective manner in good to excellent isolated yields. Mechanistic insights suggest the formation of a Co(III)-aryl key species via a rate-determining arene C[BOND]H activation during the annulation reaction

    Mechanistic Elucidation of the Arylation of Non-Spectator N-Heterocyclic Carbenes at Copper Using a Combined Experimental and Computational Approach

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    CuI(NHC)Br complexes (NHC = N-heterocyclic carbene) undergo a direct reaction with iodobenzene to give 2-arylated benzimidazolium products. The nature of the N-substituent on the NHC ligand influences the reactivity of the CuI(NHC)Br complex toward arylation. N-Benzyl or N-phenyl substituents facilitate arylation, whereas N-mesityl substituents hinder arylation. Density functional theory calculations show that an oxidative addition/reductive elimination pathway involving CuIII species is energetically feasible. A less hindered CuI(NHC)Br complex with N-benzyl groups is susceptible to oxidation reactions to give 1,3-dibenzylbenzimidazolium cations containing a CuIBr anion (various polymorphs). The results described herein are of relevance to C–H functionalization of (benz)azoles
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