Composição química e atividade antimicrobiana do óleo essencial de folhas e flores de Aloysia gratissima

Volatile oils from leaves and flowers of Aloysia gratissima were investigated for their chemical composition and antimicrobial activity against the bacteria Bacilus subtilis, Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa, Streptococcus pneumoniae and the Candida albicans yeast. The minimum inhibitory concentrations (MIC) of the oils were determined by the micro-dilution method, while the chemical composition was determined by GC-MS (gas chromatography mass spectrometry). The fresh leaves and inflorescence were subjected to hydrodistillation for 120 min using a Clevenger-type apparatus, and the essential oil was tested against microorganisms. High concentrations of sesquiterpenes were observed for the inflorescence, and monoterpenes were observed for the leaves. The main compounds of the inflorescence essential oil were E-caryophyllene, germacrene B, guaiol and bulnesol, while in the leaves the main compounds were trans-pinocamphone, trans-pinocarveyl acetate, and guaiol. The essential oil from the leaves showed an effect against P. aeruginosa and S. pneumonia, and the essential oil of the inflorescence showed an effect against P. aeruginosa, S. pneumonia, and Candida albicans.O óleo essencial de folhas e de flores de Aloysia gratissima foi avaliado quanto à composição química e ação antimicrobiana contra as bactérias Bacilus subtilis, Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa, Streptococcus pneumoniae, e a levedura Candida albicans. A concentração mínima inibitória (MIC) dos óleos essenciais foi determinada pelo método da microdiluição e a composição química determinada por CG-EM (Cromatografia Gasosa acoplada a Espectrômetro de Massas). Folhas e inflorescências frescas foram hidrodestiladas por 120 minutos em aparelho Clevenger sendo o óleo essencial testado contra microorganismos. Para as flores foi observada maior concentração de sesquiterpenos, enquanto que as folhas apresentaram maior concentração de monoterpenos. Os principais constituintes do óleo essencial da flor foram: E-cariofileno, germacreno B, guaiol e bulnesol; e das folhas foram: trans-pinocamfona, acetato de trans-pinocarveol e guaiol. O óleo essencial da folha mostrou atividade contra P. aeruginosa e S. pneumoniae, e o óleo essencial da flor mostrou atividade contra P. aeruginosa, S. pneumoniae e Candida albicans.583588Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Inverse flux quantum periodicity of magnetoresistance oscillations in two-dimensional short-period surface superlattices

Transport properties of the two-dimensional electron gas (2DEG) are considered in the presence of a perpendicular magnetic field $B$ and of a {\it weak} two-dimensional (2D) periodic potential modulation in the 2DEG plane. The symmetry of the latter is rectangular or hexagonal. The well-known solution of the corresponding tight-binding equation shows that each Landau level splits into several subbands when a rational number of flux quanta $h/e$ pierces the unit cell and that the corresponding gaps are exponentially small. Assuming the latter are closed due to disorder gives analytical wave functions and simplifies considerably the evaluation of the magnetoresistivity tensor $\rho_{\mu\nu}$. The relative phase of the oscillations in $\rho_{xx}$ and $\rho_{yy}$ depends on the modulation periods involved. For a 2D modulation with a {\bf short} period $\leq 100$ nm, in addition to the Weiss oscillations the collisional contribution to the conductivity and consequently the tensor $\rho_{\mu\nu}$ show {\it prominent peaks when one flux quantum $h/e$ passes through an integral number of unit cells} in good agreement with recent experiments. For periods $300- 400$ nm long used in early experiments, these peaks occur at fields 10-25 times smaller than those of the Weiss oscillations and are not resolved

Microwave dielectric permittivity and photoluminescence of Eu 2O3 doped laser heated pedestal growth Ta 2O5 fibers

Partilhar documento na coleção da comunidade Laboratório Associado I3NWe report the microwave dielectric properties and photoluminescence of undoped and europium oxide doped Ta2O5 fibers, grown by laser heated pedestal growth technique. The effects of Eu2O3 doping 1–3 mol % on the structural, optical, and dielectric properties were investigated. At a frequency of 5 GHz, the undoped material exhibits a dielectric permittivity of 21 and for Eu2O3 doped Ta2O5 samples it increases, reaching up to 36 for the highest doping concentration. Nevertheless, the dielectric losses maintain a very low value. For this wide band gap oxide, Eu3+ optical activation was achieved and the emission is observed up to room temperature. Thus, the transparency and high permittivity make this material promising for electronic devices and microwave applications. © 2008 American Institute of Physics.FCT-PTDC/FIS/66262/06FCT-PTDC/CTM/66195/200

TOPOGRAFIA DOS COLATERAIS CALIBROSOS DO ARCO AÓRTICO DE UM MÃO - PELADA (Procyon cancrivorus GRAY, 1865) (CARNIVORA PROCYONIADAE)

Estudou-se a topografia dos colaterais calibrosos do arco aórtico em um exemplar de Procyon cancrivorus, adulto, macho, proveniente da Fazenda Experimental do Glória, da Universidade Federal de Uberlândia, MG, Brasil, o qual teve seus vasos arteriais injetados com solução corada de Neoprene Latex 450, com posterior fixação em solução aquosa de formol a 10% e submetidos à dissecação. O arco aórtico encontra-se em correspondência à terceira costela, no antímero esquerdo da cavidade torácica. O primeiro ramo calibroso do arco aórtico é o tronco braquiocefálico, situado medialmente à terceira costela, originando as artérias carótida comum esquerda, carótida comum direita e a subclávia direita, em correspondência ao primeiro espaço intercostal. A artéria subclávia esquerda é o segundo ramo emergente do arco aórtico, originando-se medialmente à terceira costela. As artérias subclávias direita e esquerda, cedem os mesmos colaterais em ambos os antímeros, ou seja, tronco costocervical esquerdo (medialmente à primeira costela), tronco costocervical direito (borda cranial da primeira costela), artérias cervical superficial esquerda e cervical superficial direita (borda cranial da primeira costela), artéria torácica interna esquerda (medialmente à segunda costela) e artéria torácica interna direita (borda cranial da primeira costela). The topography of the thick collaterals of the aortic arch in a crab eating raccoon Procyon cancrivorus Gray, 1865, Carnivora Procyoniadae Abstract An anatomical study has been carried out on the topography of the thick collateral branches of the aortic arch in an adult male specimen of raccoon (Procyon cancrivorus) from the Gloria Experimental Farm, Federal University of Uberlandia MG, Brasil. For this purpose, the arterial blood vessels were injected with a ruddy solution of Neoprene Latex 450, fixed by means of a 10% aqueous solution of formaldehyde and then dissected. It has been observed that the aortic arch is in correspondence with the third rib at the left side of the thoracic cavity The first thick branch of the aortic arch is the brachiocephalic trunk which is situaded medially in regard to the third rib, originating the left common carotid artery, the right common carotid artery and the right subclavian artery in correspondence with the first intercostal space. The left subclavian artery is the second emerging branch of the aortic arch originating itself medialy to the third rib. The right and the left subclavian arteries give way to the same collaterals in both sides, as the left costocervical trunk (medially to the first rib), the right costocervical trunk (cranial edge of the first rib), the left and the right superficial cervical arteries (cranial edge of the first rib, the left internal thoracic artery (medially to the second rib), and the right internal thoracic artery (cranial edge of the first rib)

On the recurrence and robust properties of Lorenz'63 model

Lie-Poisson structure of the Lorenz'63 system gives a physical insight on its dynamical and statistical behavior considering the evolution of the associated Casimir functions. We study the invariant density and other recurrence features of a Markov expanding Lorenz-like map of the interval arising in the analysis of the predictability of the extreme values reached by particular physical observables evolving in time under the Lorenz'63 dynamics with the classical set of parameters. Moreover, we prove the statistical stability of such an invariant measure. This will allow us to further characterize the SRB measure of the system.Comment: 44 pages, 7 figures, revised version accepted for pubblicatio

ORIGEM E RAMIFICAÇÕES DAS ARTÉRIAS MESENTÉRICAS CRANIAL E CAUDAL EM TARTARUGA DA AMAZÔNIA Podocnemis expansa Schweigger, 1812, (Testudinata-pelomedusidae)

Foram estudadas cinco Podocnemis expansa, fêmeas, cujo peso variava de 550 a 850 g. Os animais tiveram seu sistema arterial injetado com solução corada de látex sintético, fixados e armazenados em solução aquosa de formaldeído a 10%. Após abertura da cavidade celomática, as artérias mesentéricas cranial e caudal foram dissecadas. Encontrou-se a artéria mesentérica cranial como um ramo do tronco celíaco-mesentérico e originando as artérias pancreaticoduodenal caudal, ileocólica e jejunais, que irrigam o duodeno, pâncreas, cólon, íleo e jejuno, respectivamente. A artéria mesentérica caudal origina-se da aorta (60%) ou da artéria ilíaca comum (40%), distribuindo-se para o cólon e reto. Origin and ramifications of the cranial and caudal mesenteric arteries in Amazonian turtle - Podocnemis expansa Schweigger, 1812, Testudinata-Pelomedusidae Abstract An anatomic study has been carried out on the mesenteric arteries of five Podocnemis expansa females weighing from 550 to 680 g. The animals had their artery system injected with a latex solution colored with a specific pigment and were then fixed in a 10% formol solution. After the coelomatic cavity being opened the cranial and caudal mesenteric arteries were dissected. It has been found that the cranial mesenteric artery is a branch of the coeliac mesenteric trunk while the cranial mesenteric artery gives off the pancreatic-duodenal , ileocolic and jejunal arteries that irrigate the duodenum, pancreas, colon, ileum and jejunum respectively. The aorta gives origen of as much as 60% of the caudal mesenteric artery, the remaining 40 % being originated from the common ileac artery, their branches reaching the colon and the rectum

Structural and optical properties of Er implanted AlN thin films: green and infrared photoluminescence at room temperature

In this work erbium ions were implanted into AlN films grown on sapphire with fluence range: (0.5-2) × 1015 at/cm-2, ion energy range: 150-350 keV and tilt angle: 0°, 10°, 20°, 30°. The optical and structural properties of the films are studied by means of photoluminescence and Raman spectroscopy in combination with Rutherford backscattering/channeling (RBS/C) measurements. The photoluminescence spectra of the Er3+ were recorded in the visible and infrared region between 9 and 300 K after thermal annealing treatments of the samples. The emission spectrum of the AlN:Er films consists of two series of green lines centered at 538 and 558 nm with typical Er3+ emission in the infrared at 1.54 μm. The green lines have been identified as Er3+ transitions from the 2H11/2 and 4S3/2 levels to the 4I15/2 ground state. Different erbium centers in the matrix are suggested by the change of infrared photoluminescence relative intensity of some of the emission lines when different excitation wavelengths are used. The relative abundances of these centers can be varied by using different implantation parameters. The Raman and RBS/C measurements show good crystalline quality for all the studied films.PTDC/CTM/100756/2008SFRH/BD/45774/2008Portuguese Agency GRICESBrazilian Agency CAPES the Grant 172/0