2,204 research outputs found
Antimicrobial activity of cinnamon oil (Cynnamomum zeylanicum) essential oil and its main components against Paenibacillus larvae from Argentine
No full textThe physicochemical properties, composition and antimicrobial activity of cinnamon essential oil (Cinnamomum zeylanicum) were studied. The bioactivity of this essential oil against Paenibacillus larvae was analyzed by means of a combination of in vitro tech- niques, such as the tube dilution method and bioautography, a method employed to localize antibacterial activity on a chromatogram. Cinnamaldehyde and eugenol proved to have antibacterial effects against P. larvae. Minimal inhibitory concentration (MIC) and minimal bactericide concentration (MBC) for C. zeylanicum essential oil were between 25-100 μg/ml and 125-250 μg/ml, respectively, for all strains. Essential oil and, especially, two of its main components presented inhibitory capacity against strains of P. larvae
Susceptibility of Paenibacillus larvae isolates to a tetracycline hydrochloride and Cinnamon (Cinnamomum zeylanicum) essential oil mixture
No full textThe antimicrobial activity of tetracyc line hydrochloride (OTC) and cinnamon ( Cinnamomum zeylanicum Nees) essential oil (CEO)
was evaluated against six different isolates of Paenibacillus larvae (White), the causal agent of Am erican Foulbrood (AFB) disease
in honey bee colonies. The bacteria isolates were collected from different localit ies of Argentine. Minimal inhibitory concentration
(MIC) in MYT broth by the tube dilution method was evaluated fo r each substance and for the combinations of both antimicrobials
using Krogstad and Moellering technique in order to establish the possible synergistic effects between these substances. OTC me an
MIC values were of 3.67 ± 1.80 μg/ml, while the mean MIC values obtained for CEO were of 41.67±19.17 μg/ml. An inhibitory
synergetic effect between these substances was observed with FIC index < 1 on 50% of the on P. larvae isolates
Photoelectro-chemical properties of anilino squaraine derivatives in LB films
No full textPhotocurrent generation from Langmuir-Blodgett (LB) overlays on indium tin oxide (ITO) electrodes, where the active components are 2,4-bis[4-(dibutylamino)-2-hydroxyphenyl]squaraine (1) and the unsubstituted analogue, 2,4-bis[4-(dibutylamino)phenyl]squaraine (2), have been investigated. Dye 1 shows improved behaviour compared with the latter and differences in performance are attributed to a modified aggregate structure, this being indicated by variations in the LB film spectra. The photocurrent generation is enhanced by the presence of electron accepters, e.g. N,N'-dimethyl-4,4'-bipyridinium diiodide (MV2+), but quenched by electron donors, e.g. hydroquinone (HQ). The concentration dependence is reported
Essentials oils of some Mentha spp. and their relation with antimicrobial activity against Paenibacillus larvae, the causative agent of American foulbrood in honey bees, by using the bioautography technique
No full textEssential oils of three mint species (Mentha aff. arvensis, Mentha aff. rotundifolia and a probably feral hybrid of Mentha spp.) were investigated for their antimicrobial properties against Paenibacillus larvae (White). The bioactivity of the oils was compared using the combination of in vitro techniques such as microdilution, agar dilution and bioautography. The chemical composition of the oils was analyzed by GC/MS. Using the bioautography assay, menthol, menthone, menthofuran and piperitone oxide were found to be responsible for the antimicrobial activity of these oils. A quantitative structure-activity relationship (QSAR) model was developed for four terpenoids with significant antimicrobial activity using Hyperchem 8.0 and Gaussian 03 software. The QSAR approach leads to a better understanding of the structural properties of these terpenoids which are responsible for bioactivity. The present work reports the first systematic study about the use of QSAR properties to correlate antimicrobial activity of natural substances against P. larvae
Comments on author citations for nomenclatural novelties published in volume 15 of the Flora Reipublicae Popularis Sinicae (FRPS)
No full textLearning theories and interprofessional education: a user's guide
No full textThere is increasing interest in the theoretical underpinning of interprofessional education (IPE) and writers in this field are drawing on a wide range of disciplines for theories that have utility in IPE. While this has undoubtedly enriched the research literature, for the educational practitioner, whose aim is to develop and deliver an IPE curriculum that has sound theoretical underpinnings, this plethora of theories has become a confusing, and un-navigable quagmire. This article aims to provide a compass for those educational practitioners by presenting a framework that summarizes key learning theories used in IPE and the relationship between them. The study reviews key contemporary learning theories from the wider field of education used in IPE and the explicit applications of these theories in the IPE literature to either curriculum design or programme evaluation. Through presenting a broad overview and summary framework, the study clarifies the way in which learning theories can aid IPE curriculum development and evaluation. It also highlights areas where future theoretical development in the IPE field is required
Photoelectrochemistry of Langmuir-Blodgett films of a C-60 iminodiacetic acid ester derivative on ITO electrodes
No full textThe photoelectrochemical response of a C-60 iminodiacetic acid ester derivative (C(60)IDA), deposited on ITO electrodes by means of the Langmuir-Blodgett technique, has been investigated. The anodic photocurrent observed on the modified electrode corresponds to an electron transfer from the electrolyte through the LB film to the electrode. The action spectrum of photocurrent indicates C60IDA as the photoactive species in the photoinduced electron transfer process. Positive bias voltage, reducing agent and higher pH of the solution are beneficial factors for generating higher photocurrent. The quantum yield for photocurrent generation is 0.94% and can be raised to 3.40% under favorable conditions. (C) 1998 Elsevier Science S.A. All rights reserved.Materials Science, MultidisciplinaryPhysics, Condensed MatterPolymer ScienceSCI(E)EI9ARTICLE3223-2279
Factorization of weakly compact operators between Banach spaces and Fréchet or (LB)-spaces
No full text[EN] In this note we show that weakly compact operators from a Banach space X into
a complete (LB)-space E need not factorize through a reflexive Banach space. If E is a Fréchet space, then weakly compact operators from a Banach space X into E factorize through a reflexive Banach space. The factorization of operators from a Fréchet or a complete (LB)-space into a Banach space mapping bounded sets into relatively weakly compact sets is also investigated.The research of the first author was partially supported by MEC and FEDER Project MTM2010-15200 and by GV Project Prometeo/2008/101. The support of the University of Aberdeen and the Universidad Polit´ecnica of Valencia is gratefully acknowledged.Bonet Solves, JA.; Wright, JM. (2012). Factorization of weakly compact operators between Banach spaces and Fréchet or (LB)-spaces. Matematicki Vesnik. 64(4):330-335. https://riunet.upv.es/handle/10251/58753S33033564
Simulating liquid droplets: A quantitative assessment of lattice Boltzmann and Volume of Fluid methods
No full textWhile various multiphase flow simulation techniques have found acceptance as predictive tools for processes involving immiscible fluids, none of them can be considered universally applicable. Focusing on accurate simulation of liquid-liquid emulsions at the scale of droplets, we present a comparative assessment of the single-component multiphase pseudopotential lattice Boltzmann method (PP-LB, classical and modified) and the Volume of Fluid method (VOF, classical and modified), highlighting particular strengths and weaknesses of these techniques. We show that a modified LB model produces spurious velocities 1–3 orders of magnitude lower than all VOF models tested, and find that LB is roughly 10 times faster in computation time, while VOF is more versatile. Simulating falling liquid droplets, a realistic problem, we find that despite identical setups, results can vary with the technique in certain flow regimes. At lower Reynolds numbers, all methods agree reasonably well with experimental values. At higher Reynolds numbers, all methods underpredict the droplet Reynolds number, while being in good agreement with each other. Particular issues regarding LB simulations at low density ratio are emphasized. Finally, we conclude with the applicability of VOF vis-à-vis PP-LB for a general range of multiphase flow problems relevant to myriad applications.Accepted Author ManuscriptChemE/Transport PhenomenaIntensified Reaction and Separation System
Nonadaptive Amino Acid Convergence Rates Decrease over Time.
No full textConvergence is a central concept in evolutionary studies because it provides strong evidence for adaptation. It also provides information about the nature of the fitness landscape and the repeatability of evolution, and can mislead phylogenetic inference. To understand the role of adaptive convergence, we need to understand the patterns of nonadaptive convergence. Here, we consider the relationship between nonadaptive convergence and divergence in mitochondrial and model proteins. Surprisingly, nonadaptive convergence is much more common than expected in closely related organisms, falling off as organisms diverge. The extent of the convergent drop-off in mitochondrial proteins is well predicted by epistatic or coevolutionary effects in our "evolutionary Stokes shift" models and poorly predicted by conventional evolutionary models. Convergence probabilities decrease dramatically if the ancestral amino acids of branches being compared have diverged, but also drop slowly over evolutionary time even if the ancestral amino acids have not substituted. Convergence probabilities drop-off rapidly for quickly evolving sites, but much more slowly for slowly evolving sites. Furthermore, once sites have diverged their convergence probabilities are extremely low and indistinguishable from convergence levels at randomized sites. These results indicate that we cannot assume that excessive convergence early on is necessarily adaptive. This new understanding should help us to better discriminate adaptive from nonadaptive convergence and develop more relevant evolutionary models with improved validity for phylogenetic inference
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