534 research outputs found
Supplemental_material_DISC851130 – Supplemental material for Expanding the Biological Application of Fluorescent Benzothiadiazole Derivatives: A Phenotypic Screening Strategy for Anthelmintic Drug Discovery Using Caenorhabditis elegans
No full textSupplemental material, Supplemental_material_DISC851130 for Expanding the Biological Application of Fluorescent Benzothiadiazole Derivatives: A Phenotypic Screening Strategy for Anthelmintic Drug Discovery Using Caenorhabditis elegans by Giovana A. S. Cintra, Brenno A. D. Neto, Pedro H. P. R. Carvalho, Carolina B. Moraes and Lucio H. Freitas-Junior in SLAS Discovery</p
Identification of carotenoid isomers by mass spectrometry in crude and bleached palm oil.
No full textIdentification of carotenoid isomers in crude and bleached palm oils by mass spectrometry
No full textCoelho Neto Canibal: Pseudônimos shakespearianos e literatura licenciosa no Brasil (1890-1940) / Coelho Neto Cannibal: Shakespearean pseudonyms and licentious literature in Brazil (1890-1940)
No full textResumo: Este trabalho estuda a trajetória do pseudônimo shakespeariano Caliban, adotado pelo escritor Henrique Coelho Neto (1864-1934), em 1890, para veicular literatura licenciosa nos impressos. Acompanhamos o pseudônimo desde sua estreia até sua última aparição no mundo editorial na década de 1940. Para levar a cabo a tarefa, consultamos os livros publicados por Caliban e investigamos sua atuação na imprensa periódica por meio da consulta online dos jornais na Hemeroteca Digital Brasileira. Caliban foi um autor de sucesso e parte desse reconhecimento vinha da origem erudita de seu nome. O filtro shakespeariano era crucial para a aceitação dessa literatura nos circuitos letrados, mas muitos a consideravam como mera pornografia. A literatura de Caliban revela um Coelho Neto moderno, contestador e inovador que foi esquecido pela tradição crítica.Palavras-chave: Coelho Neto; William Shakespeare; Caliban; literatura licenciosa.Abstract: This work studies the trajectory of the Shakespearean pseudonym “Caliban”, adopted by writer Henrique Coelho Neto (1864-1934) in the 1890s to convey licentious literature in print. We follow the pseudonym from its debut until its last appearance in the publishing world in the 1940s. To carry out the task, we consulted the books published by Caliban and investigated his performance in the periodic press through online consultation of newspapers in the Hemeroteca Digital Brasileira. Caliban was a successful author and part of that recognition came from the erudite origin of his name. The Shakespearean filter was crucial for the acceptance of this literature in literary circuits, but many considered it as mere pornography. Caliban’s literature reveals a modern, challenging and innovative Coelho Neto who has been overlooked by critical tradition.Keywords: Coelho Neto; William Shakespeare; Caliban; licentious literature
On the Control of Surface Waves in Integrated Antennas: Analysis and Design Exploiting Artificial Dielectric Layers
No full textPlanar printed antenna technologies, due to their light weight, low profile, cost effectiveness and ease of connection with the active devices (e.g., amplifiers etc.), are becoming an attractive solution for the commercial data-hungry applications, such as 60 GHz high-data rate communication. Another commercial application of planar antennas includes the exponentially growing lucrative industry of automotive radars. Such radar systems not only require highly reliability since human lives are involved, but also extreme integration to serve the purpose of compactness and cost. Therefore, it is desirable to have all the system functionalities on a single silicon chip, which can then easily be combined with either off- or on-chip antennas/antenna arrays. In such scenarios, planar printed antennas/arrays, because of their low profile and ability to be integrated, are emerging as an alternative to the bulky and expensive dielectric lenses. Although planar antennas show advantageous properties, there are two major challenges associated with their design, namely surface waves and front-to-back radiation ratio. In this thesis, a innovative planar methodology is presented to solve the aforementioned bottlenecks. The proposed technique can be used to obtain simultaneously high radiation efficiency (i.e., minimal surface wave excitation) and good front-to-back radiation ratio. This solution consist of engineering anisotropic equivalent materials, referred to as artificial dielectric layers (ADLs), and using them to enhance the performance of planar antennas. A practical planar realization of this concept can be achieved by embedding inside the host dielectric a periodic array of sub-wavelength square metal patches in a multilayer configuration. In this work, the main aspects pertaining to the theoretical development and the practical implementation of ADLs are investigated. The analysis of ADLs is extensively investigated in this thesis in order to understand the physical phenomena characterizing these structures. Moreover, this study also provides the guidelines to design such kind of engineered materials. The modeling of ADLs is first implemented for two-dimensional structures, and then generalized to three-dimensional geometries. A rigorous analytical formulation is presented to model ADLs of finite height by including the higher-order interaction between parallel sheets in closed form. From the equivalent impedance of the layers, a transmission line model that provides the spectral Green's function of ADLs is constructed. This allows to characterize the propagation through finite ADLs and to study their dispersion characteristics. The analysis shows that an ADL slab is equivalent to a dense material for the plane waves incident in directions close to the normal, whereas it exhibits lower effective permittivity for the waves that are incident close to the grazing angle. This peculiar anisotropic property can be exploited to design antenna superstrates which, one one hand, exhibit high surface-wave efficiency over a wide band and, on the other hand, provide high front-to-back ratio. The advantages of using ADL superstrates in the antenna designs is experimentally demonstrated by the development of two prototype demonstrators. The first design operates at X-band and is realized using commercial printed circuit board (PCB) technology. The second prototype consists of an on-chip antenna working at 0.3 THz, which is fabricated using an in-house integrated circuit process. This study highlights that the ADL superstrates can be designed and manufactured independently from the antenna and the circuit. This allows their use as add-on components, since no accurate alignment is required between the antenna and the superstrate layers. Moreover, ADL are broadband because of their non-resonant nature. The last part of this thesis deals with a novel concept of wideband wide-scanning phased array designs, based on connected arrays of slots loaded with ADL superstrates. The proposed structure has two main advantages with respect to the existing solutions. Firstly, it is completely planar and realized with a single multilayer PCB, with consequent reduction of the cost and the complexity of the array. Secondly, ADLs are used in place of real dielectric superstrates, to achieve much better efficiency in terms of surface-wave loss. For the design of the array loaded with ADL, including the adhesive layers, an analytical tool, based on spectral Green's function, is used. This tool allows to estimate the performance of the array with minimal computational resources. The design of a wideband feed structure is also proposed, which does not require balanced-to-unbalanced (balun) transitions that limit the matching bandwidth.Microelectronics-THz Sensing GroupElectrical Engineering, Mathematics and Computer Scienc
Closed-form solutions for the analysis of artificial dielectric layers under generic field incidence
No full textWe present an analytical method to model artificial dielectric layers (ADLs) of finite height. Starting from the closed-form solution for the scattering from a single layer under plane wave illumination, the formulation is extended to the multi-layer case, by including the higher-order interaction between parallel layers in analytical form. The method can be used to describe the radiation of a source located in the close proximity of the ADL. Experimental data obtained from a prototype demonstrator are presented and show a good agreement with the results of the theoretical analysis.Accepted author manuscriptTera-Hertz Sensin
ESIPT or not ESIPT? Revisiting recent results on 2,1,3-benzothiadiazole under the TD-DFT light
No full textInternational audienceRecently, the spectroscopic signatures of amino-substituted benzothiadiazoles were investigated by complementary experimental and theoretical approaches [Neto et al., RSC Adv., 2012, 2, 1524-1532]. It was concluded that these molecules were exhibiting excited-state intramolecular proton transfer. In this communication, we revisit these results using a state-of-the-art time-dependent density functional theory approach which provides a complete explanation to the spectroscopic observations
Phosphine-free heck reaction: mechanistic insights and catalysis “on water” using a charge-tagged palladium complex
No full textA novel Pd-complex with a charge tag (imidazolium cation) was applied for online monitoring of the neutral Heck reaction by electrospray ionization (tandem) mass spectrometry-ESI-MS(/MS). The results shed light on the mechanism of the reaction, whereas the charge-tagged ligand also allowed the unprecedented MS monitoring of Pd2+ reduction to Pd0. Key reaction intermediates associated with Pd catalysis could also be detected and characterized due to the presence of the charge tag on the Pd-complex. DFT calculations supported the proposed mechanism. The new charge-tagged Pd-complex is also shown to function as an active catalyst "on water" with the advantage of using cheaper and less reactive aryl chloride substrates in a phosphine-free version of the Heck reaction. © the Partner Organisations 2014.A novel Pd-complex with a charge tag (imidazolium cation) was applied for online monitoring of the neutral Heck reaction by electrospray ionization (tandem) mass spectrometry – ESI-MS(/MS). The results shed light on the mechanism of the reaction, whereas38729582963CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFsem informaçãosem informaçãosem informaçãosem informaçãosem informaçãosem informaçãoKandukuri, S.R., Schiffner, J.A., Oestreich, M., (2012) Angew. Chem., Int. Ed., 51, pp. 1265-1269Faulkner, A., Bower, J.F., (2012) Angew. Chem., Int. 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Sondas fluorescentes lipofílicas do tipo AIEE derivados do núcleo 2,1,3-benzotiadiazola (BTD)
No full textTese (doutorado) — Universidade de Brasília, Instituto de Química, Programa de Pós-Graduação em Química, 2021.Neste trabalho, três moléculas orgânicas fluorescentes derivadas do núcleo 2,1,3-benzotiadiazola (BTD), foram sintetizadas através da reação de acoplamento cruzado de Sonogashira com o fenilacetileno, e utilizadas como sondas fluorescentes seletivas para gotas lipídicas em imageamento celular. Dentre as características requeridas para esses tipos de sondas fluorescentes, tem-se o aumento ou ativação de intensidade de emissão de fluorescência no estado agregado, ou seja, a não ocorrência do efeito ACQ (Aggregation Caused Quench). Dessa forma, a arquitetura molecular dessas sondas foi planejada de modo a apresentarem design D-π-A e comportamento AIEE (Aggregation-Induced Emission Enhancement) no estado de agregação. A análise fotofísica e o espalhamento dinâmico de luz (DLS) demonstraram que as BTDs formam agregados em água associadas a um aumento da intensidade de fluorescência, devido ao efeito AIEE (Aggregation-Induced Emission Enhancement). Pela primeira vez foram aplicados com sucesso o modelo cinético de Finke-watzky e as leis de deformação Arrhenius (comportamento super-Arrhenius) para a elucidação dos processos dinâmicos de agregação/quebra de nanoagregados orgânicos. O coeficiente de partição e o teste SDS determinaram a lipofilicidade e o efeito light-up em meio lipofílico das BTDs. Os cálculos DFT revelaram que a Transferência Intramolecular de Carga (ICT) foi responsável pelas propriedades fluorescentes, o que é esperado para moléculas fluorescentes de design D-π-A. A técnica de ressonância paramagnética eletrônica (RPE) foi usada eficientemente para a caracterização da dinâmica do estado excitado e confirmação da estabilização do estado excitado pelo processo ICT. O uso das BTDs para a marcação de gotas lipídicas apresentou excelentes resultados, e as gotas lipídicas puderam ser marcadas seletivamente, quando comparados com o marcador comercialmente disponível (BODIPY), com emissões variando do azul ao vermelho.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).Three fluorescent 2,1,3- benzothiadiazole (BTD) small-molecules derivatives, were synthesized through Sonogashira cross-coupling reaction with phenylacetylene, and applied as stain for the selective imaging of lipid droplets (LDs). Among the characteristics required for these types of fluorescent probes, there is the increase or activation of fluorescence emission intensity in the aggregate state, that is, the non-occurrence of the ACQ (Aggregation Caused Quench) effect. Thus, the molecular architecture of these probes was planned in such a way as to present D-π-A design and AIEE (Aggregation-Induced Emission Enhancement) behavior in the aggregation state. Photophysical analysis and dynamic light scattering (DLS) demonstrated that BTDs form aggregates in water associated with an increase in fluorescence intensity, due to the AIEE effect (Aggregation-Induced Emission Enhancement). For the first time, the Finke-watzky kinetic model and the Arrhenius deformation laws (super-Arrhenius behavior) were successfully applied to elucidate the dynamic processes of aggregation / breaking of organic nanoaggregates. The partition coefficient and the SDS test determined the lipophilicity and the light-up effect in lipophilic ambient. DFT calculations revealed that the Intramolecular Charge Transfer (ICT) was responsible for the fluorescent properties, which is expected for fluorescent molecules of design D-π-A. The electronic paramagnetic resonance (EPR) technique was used efficiently to characterize the excited state dynamics and confirm the stabilization of the excited state by the ICT process. The use of BTDs for live-cells staining showed excellent results, and lipid droplets (LDs) could be selectively stained, when compared with the commercially available dye (BODIPY), with emissions ranging from blue to red.Instituto de Química (IQ)Programa de Pós-Graduação em Químic
Recent Developments in the Chemistry of Deoxyribonucleic Acid (DNA) Intercalators: Principles, Design, Synthesis, Applications and Trends
No full textIn the present overview, we describe the bases of intercalation of small molecules (cationic and polar neutral compounds) in DNA. We briefly describe the importance of DNA structure and principles of intercalation. Selected syntheses, possibilities and applications are shown to exemplify the importance, drawbacks and challenges in this pertinent, new, and exciting research area. Additionally, some clinical applications (molecular processes, cancer therapy and others) and trends are described
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