Fluorescent Symmetric Phenazines from Naphthoquinones

Pinto, Antônio V.; Pinto, Cleverson N.; Pinto, Maria do Carmo F. R.; Emery, Flávio da Silva; Moura, Kelly C. G. de; Carvalho, C. A. A. de; Brinn, Ira M.

doi:10.3987/com-97-7905

Cited by 53 publications

(66 citation statements)

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“…[1][2][3] Dentre as diversas metodologias para a obtenção dos derivados cíclicos, podemos citar aquelas que envolvem a ciclização direta do lapachol (1), de seu acetato 5 ou epóxido 6. [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] De modo geral, estas reações levaram à formação de uma mistura complexa de produtos. Entretanto, a α-xiloidona (2) pôde ser preparada em bons redimentos pelo refluxo de 1 em piridina, 24 pela sua transformação usando microorganismos, 25 ou pelo uso de MnO 2 como reagente.…”

Section: Introductionunclassified

“…Entretanto, a α-xiloidona (2) pôde ser preparada em bons redimentos pelo refluxo de 1 em piridina, 24 pela sua transformação usando microorganismos, 25 ou pelo uso de MnO 2 como reagente. 26 Mais recentemente, 2 foi preparado pela irradiação de 1 por microondas usando alumina/sílica-gel/montmorillonita como suporte. 27 A α-lapachona (7) e a β-lapachona (8) foram preparadas seletivamente usando HCl 29 e H 2 SO 4 ou AlCl 3 , 30 respectivamente.…”

Section: Introductionunclassified

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Ciclização do lapachol induzida por sais de tálio III

Ribeiro¹,

Souza²,

Ferreira³

et al. 2008

Quím. Nova

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Recebido em 29/11/07; aceito em 7/3/08; publicado na web em 9/4/08 CYCLIZATION OF LAPACHOL INDUCED BY THALLIUM SALTS. This work describes the cyclization of lapachol (1) induced by thallium triacetate (TTA) and thallium trinitrate (TTN) in several solvents using magnetic stirring and under microwave irradiation. α-Xyloidone (2) -dehydro-α-lapachone -was obtained as the main product in these reactions in 20 -75% yield. However, rhinacanthin-A (4) was isolated as main product in a 40% yield, using TTA and acetic anhydride:water (1:1) as solvent, and dehydroiso-α-lapachone (3) in 21% yield, using TTA and dichloromethane as solvent. The reaction time decreased drastically under microwave conditions, but the yields of these reactions were not the expected.

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Section: Introductionunclassified

Ciclização do lapachol induzida por sais de tálio III

Ribeiro¹,

Souza²,

Ferreira³

et al. 2008

Quím. Nova

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“…Recently it is showed that the fractional model perfectly fits the test data of memory phenomena in different disciplines [46] they have found that a possible physical meaning of the fractional order is an index of memory. From this viewpoint fractional calculus has found many applications in new research on physics of biological structures and living organisms, from DNA dynamics [47][48][49] to protein folding [50], cancer cells [51], tumor-immune system [52], modeling of some human autoimmune diseases such as psoriasis [53], bioimpedance [54], spiking neurons [55], and also the transport of drugs across biological materials and human skin [56] and electrical impedance applied to human skin [57] and even modeling of HIV dynamics [58].…”

Section: Fractional Calculus In Bioscience and Biomedicinementioning

confidence: 99%

Fractional Dynamics in Bioscience and Biomedicine and the Physics of Cancer

Nasrolahpour

2017

Preprint

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Almost all phenomena and structures in nature exhibit some degrees of fractionality or fractality. Fractional calculus and fractal theory are two interrelated concepts. In this article we study the memory effects in nature and particularly in biological structures. Based on this fact that natural way to incorporate memory effects in the modeling of various phenomena and dealing with complexities is using of fractional calculus, in this article we present different examples in various branch of science from cosmology to biology and we investigate this idea that are we able to describe all of such these phenomena using the well-know and powerful tool of fractional calculus. In particular we focus on fractional calculus approach as an effective tool for better understanding of physics of living systems and organism and especially physics of cancer.Keywords: Fractional Dynamics; Memory Effect; Biological Structures; Physics of Cancer IntroductionThe concept of memory effect plays an important role in a large number of phenomena in different contexts and systems from biological structures to cosmological phenomena. For instance: memory effects in nanoscale systems [1,2], optical memory effect [3], gravitational and cosmological memory effect (which means: the induction of a permanent change in the relative separation of the test particles when gravitational radiation passes through a configuration of test particles that make up a gravitational wave detector) [4], memory effects in gene regulatory networks [5], memory effects in economics [6] have been investigated. In addition other kinds of memory effect including: shape memory effect [7][8][9][10], magnetic shape memory effect [11] and temperature memory effect [12] have been also considered in recent years. In all above mentioned references authors have used the standard calculus, however nowadays it is well-known that a natural way to incorporate memory effects in the modeling of various phenomena is using of fractional calculus. On the other hand almost all phenomena and structures in nature exhibit some degrees and levels of fractionality or fractality (low or high level or something between them), also nowadays it is well-known that there is a close relation between fractality and fractionality. In this work we investigate this idea that are we able to describe all of such these phenomena using the well-know and powerful tool of fractional calculus. Therefore for this purpose in the following, concepts of fractality and fractional dynamics are briefly reviewed respectively in Sec. 2.Then in Sec. 3 we introduce fractional calculus as a powerful tool for modeling of memory effects in different context and we present some important applications. At last, in Sec. 4, we will present some conclusions.

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“…Studies [5,19,20] of the diffusion of a solute through the interstices of the dense phase to an active particle have shown that mass transfer coefficients are predicted well for a large range of Peclet numbers, by:…”

Section: Transfer Rate During Bubble Formationmentioning

confidence: 99%

99/01467 Measurement of mass transfer between the bubble and dense phases in a fluidized bed combustor

1999

Fuel and Energy Abstracts

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An experimental study is described on mass transfer between the bubble and dense phases in a fluidized bed, used as a coke combustor. The experimental technique allowed quantification of the mass transfer rate during bubble formation and during a bubble's rise through the bed. The combustion experiments were performed at 1 atm and 1223 K, in a fluidized bed (i.d. 120 mm) of sand (average diam. 325 m) with static heights of 0.10 -0.21 m. The bubbling flow rate ranged from 2.5 to 5.0 times that at incipient fluidization. The coke particles were 3.0 or 3.5 mm in diameter. Results indicate that the equivalent bed height, L eq (the height a bubble must rise to transfer to the dense phase the same quantity of oxygen as during its formation) is independent of the bubbling air flow rate. The mean value L eq ϭ 50 mm suggests that for shallow beds the mass transferred during bubble formation is a significant part of the total mass transferred. The measured mass transfer factor between phases during a bubble's rise ( xЈ ϭ X/L mf ) is independent of the bubbling air flow rate and substantially lower than the theoretical predictions of Kunii and Levenspiel [1]. This disagreement is explained by the fact that the theoretical model is for an isolated bubble and does not account for the strong interaction between consecutive bubbles; this increases a bubble's velocity and induces their coalescence, leading to a decrease in mass transferred between phases. © 1998 by The Combustion Institute NOMENCLATURE

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Fluorescent Symmetric Phenazines from Naphthoquinones

Cited by 53 publications

References 0 publications

Ciclização do lapachol induzida por sais de tálio III

Ciclização do lapachol induzida por sais de tálio III

Fractional Dynamics in Bioscience and Biomedicine and the Physics of Cancer

99/01467 Measurement of mass transfer between the bubble and dense phases in a fluidized bed combustor

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