Deposited Transition Metal‐Centered Porphyrin and Phthalocyanine Molecules: Influence of the Substrates on the Magnetic Properties

The field of molecular spintronics has gained much attention since molecules withmagnetic centers form natural magnetic units, which do not suffer from the size limitations of conventional electronics, opening a new path towards miniaturization. To fabricate devices, the molecules have to be deposited on a substrate. The key questions are the interaction of the molecules with the substrate and the control of the magnetic properties. Considering molecule‐substrate hybrid interfaces as building blocks for spintronic devices, a deep understanding of the electronic structure and the coupling mechanisms is central to future applications. The orientation and reconstruction of the substrates can strongly affect the electronic and magnetic characteristics of the adsorbed molecule and drastically change the properties of the free molecules. In this chapter, we will discuss the interaction of transition metal‐centered porphyrins and phthalocyanines with different types of substrates, for example, ferromagnetic transition metals or graphene sheets, in the framework of state‐of‐the‐art density functional theory methods plus insights gained from X‐ray absorption/X‐ray magnetic circular dichroism experiments. The goal is to give an insight into the relevant processes on the atomic scale and to present possible routes to tailor magnetic properties in molecule‐substrate hybrid structures

Characterization of gas phase iron phthalocyanine with X-ray photoelectron and absorption spectroscopies

Despite the numerous studies dedicated to phthalocyanine molecules adsorbed on surfaces, in monolayer or thin film, very few works have been focused on the characterization of vapors of these molecules. In this article we present the C 1s, N 1s and Fe 2p photoemission results as well as N K-edge X-ray absorption data of iron phthalocyanine (FePc) in gas phase. Presented comparison of X-ray photoelectron spectroscopy and X-ray absorption spectroscopy spectra of FePc films show a great similarity with the gas phase results, con- firming the molecular character of thick films. The Fe 2p photoemission spectrum of the gas phase FePc, shown for the first time, can be considered as a fingerprint of the Fe(II) ionic state of the central metal of the iron phthalocyanine. The performed multiplet calculations for describing the Fe 2p XP spectrum indicate 3 Eg (a1g 2 eg 3 b2g 1 ) state as the most probable ground state for thick film of iron phthalocyanine

Elucidating the 3d Electronic Configuration in Manganese Phthalocyanine

To shed light on the metal 3d electronic structure of manganese phthalocyanine, so far controversial, we performed photoelectron measurements both in the gas phase and as thin film. With the purpose of explaining the experimental results, three different electronic configurations close in energy to one another were studied by means of density functional theory. The comparison between the calculated valence band density of states and the measured spectra revealed that in the gas phase the molecules exhibit a mixed electronic configuration, while in the thin film, manganese phthalocyanine finds itself in the theoretically computed ground state, namely, the b12ge3ga1gb01g electronic configuration

AVALIAÇÃO DA ATIVIDADE in vitro DO FIPRONIL CONTRA LARVAS NÃO ALIMENTADAS DE Dermacentor nitens

O carrapato Dermacentor nitens parasita preferencialmente equinos e é popularmente conhecido como carrapato da orelha dos cavalos. A infestação por este parasito promove prejuízos ao animal pela espoliação sanguínea, queda na produtividade, predisposição ao aparecimento de miíases e infecções bacterianas secundárias, além de ser vetor do protozoário Babesia caballi, agente causador da babesiose equina. Assim, o objetivo deste trabalho é avaliar a atividade acaricida in vitro do fipronil, em três diferentes metodologias, contra larvas não alimentadas de D. nitens. Os ensaios foram realizados em duplicata, com larvas não alimentadas de 17 dias, obtidas na colônia do Laboratório de Quimioterapia Experimental em Parasitologia Veterinária (LQEPV) no Instituto de Veterinária (IV) da Universidade Federal Rural do Rio de Janeiro (UFRRJ). As seguintes concentrações de fipronil foram testadas: 1; 2,5; 5; 10; 20; 40; 60; 80 e 100 ppm, obtidas a partir da diluição de fipronil técnico em água e triton-x para as metodologias de imersão larval (LIT) e de LIT adaptado, e em azeite de oliva extra virgem e tricloroetileno (2:1) para a metodologia de pacote de larvas (LPT). Na metodologia LIT, 300 larvas foram imersas em um microtubo com 1mL de solução por 10 minutos. Após drenar a solução, as larvas foram secas e aproximadamente 100 colocadas em envelope de papel filtro (6x6cm). Para LIT adaptado, aproximadamente 100 larvas foram depositadas em um sanduíche de papel filtro (2x2cm) impregnado com 500 µL da solução. Cada sanduíche foi acondicionado em envelope de papel filtro (6x6cm). E para LPT, o papel filtro (8,5x7,5cm) foi previamente impregnado com 670 µL de solução. Após duas horas de secagem, foram feitos envelopes e cerca de 100 larvas foram alocadas em cada. Para as três metodologias, o armazenamento foi feito em estufa climatizada com demanda controlada de oxigênio a 27ºC e 80% UR. Após 24 horas foi realizada leitura para avaliação da mortalidade, de acordo com a seguinte fórmula: % de mortalidade = total de larvas mortas x 100 / total de larvas. Os dados encontrados foram tabulados e os valores das concentrações letais CL50 e CL90 foram calculadas estatisticamente por meio da análise Probit utilizando o programa computacional R versão 3.6.1. Para LIT, a CL50 foi de 3,04 ppm (2,36-3,77 ppm), e a CL90 de 22,29 ppm (17,94-28,77 ppm). O slope obtido foi de 1,481±0,334 e o R de 0,584. Enquanto LIT adaptado, a CL50 foi de 14,32 ppm (12,79-15,98 ppm), e a CL90 de 49,19 ppm (42,48-58,30 ppm), e em LPT a CL50 foi de 20,77 ppm (18,50-23,33 ppm), e a CL90 de 80,06 ppm (67,63-97,58 ppm), maiores que as obtidas em LIT. O slope obtido foi de 2,391±0,130 e o R de 0,899 para LIT adaptado, e para LPT o slope foi de 2,187±0,418 e o R de 0,973. Portanto, o fipronil demonstrou ação larvicida in vitro contra D. nitens nas concentrações avaliadas, tornando este fenilpirazol um provável ativo utilizado para o controle deste carrapato, além de LIT ter sido a metodologia mais sensível em que se obteve as menores CLs para o fipronil

Epigenetic control of the ubiquitin carboxyl terminal hydrolase 1 in renal cell carcinoma

<p>Abstract</p> <p>Background</p> <p>The ubiquitin carboxyl-terminal hydrolase 1 (UCHL1) gene involved in the regulation of cellular ubiquitin levels plays an important role in different cellular processes including cell growth and differentiation. Aberrant expression of UCHL1 has been found in a number of human solid tumors including renal cell carcinoma (RCC). In RCC, UCHL1 overexpression is associated with tumor progression and an altered von Hippel Lindau gene expression.</p> <p>Methods</p> <p>To determine the underlying mechanisms for the heterogeneous UCHL1 expression pattern in RCC the UCHL1 promoter DNA methylation status was determined in 17 RCC cell lines as well as in 32 RCC lesions and corresponding tumor adjacent kidney epithelium using combined bisulfite restriction analysis as well as bisulfite DNA sequencing.</p> <p>Results</p> <p>UCHL1 expression was found in all 32 tumor adjacent kidney epithelium samples. However, the lack of or reduced UCHL1 mRNA and/or protein expression was detected in 13/32 RCC biopsies and 7/17 RCC cell lines and due to either a total or partial methylation of the UCHL1 promoter DNA. Upon 2'-deoxy-5-azacytidine treatment an induction of UCHL1 mRNA and protein expression was found in 9/17 RCC cell lines, which was linked to the demethylation degree of the UCHL1 promoter DNA.</p> <p>Conclusion</p> <p>Promoter hypermethylation represents a mechanism for the silencing of the UCHL1 gene expression in RCC and supports the concept of an epigenetic control for the expression of UCHL1 during disease progression.</p