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This work presents an overview of the evolution of mathematical modeling applied to the context of epidemics and the advances in modeling in epidemiological studies. In fact, mathematical treatments have contributed substantially in the epidemiology area since the formulation of the famous SIR (susceptible-infected-recovered) model, in the beginning of the 20th century. We presented the SIR deterministic model and we also showed a more realistic application of this model applying a stochastic approach in complex networks. Nowadays, computational tools, such as big data and complex networks, in addition to mathematical modeling and statistical analysis, have been shown to be essential to understand the developing of the disease and the scale of the emerging outbreak. These issues are fundamental concerns to guide public health policies. Lately, the current pandemic caused by the new coronavirus further enlightened the importance of mathematical modeling associated with computational and statistical tools. For this reason, we intend to bring basic knowledge of mathematical modeling applied to epidemiology to a broad audience. We show the progress of this field of knowledge over the years, as well as the technical part involving several numerical tools.

In the present work, we report the first rotational study of

Hylaeamys megacephalus (G. Fisher, 1814) presents great genetic diversity and wide geographical distribution, and occurs in both the Amazon and Cerrado biomes. Because of its generalist aspect, this species tolerates different eating habits and habitats. It occurs in flooded and dry areas and is predominantly terrestrial, which allows greater gene flow between populations even over long distances. Studies that seek a better understanding of morphological variations resulting from differences imposed by the environment throughout this species’ distribution are still lacking. This study aimed to analyze the differences between H. megacephalus populations based on craniometry, investigating whether the environment has an influence on morphology. We analyzed a total of 142 specimens from three scientific mammal collections: National Museum, “Universidade Federal do Rio de Janeiro” (MN-UFRJ); “Laboratório de Biologia e Parasitologia de Mamíferos Reservatórios Silvestres”, “Instituto Oswaldo Cruz”, “Fundação Oswaldo Cruz”(LBCE-Fiocruz); and “Laboratório de Biodiversidade”, “Universidade Federal de Goiás”, “Regional Jataí” (LZE-UFG), and took 20 craniometric measurements. Craniometry was explored using unweighted pair group method with arithmetic mean (UPGMA), canonical variate analysis, and principal component analysis (PCA). The results led us to conclude that there are three craniometric groups of H. megacephalus with a tendency to differentiate as a result of geographical influences. RESUMO: Com grande diversidade genética e distribuição geográfica, Hylaeamys megacephalus (G. Fisher, 1814) ocorre tanto na Amazônia quanto no Cerrado. Visto seu aspecto generalista, esta espécie tolera diversos hábitos alimentares e habitats, ocorrendo em áreas inundadas ou não, sendo predominantemente terrestre, permitindo maior fluxo de genes entre as populações, mesmo em longas distâncias. Apresenta ampla distribuição, e carece de estudos que busquem um melhor entendimento sobre as variações morfológicas resultantes das diferenças impostas pelo meio ao longo de sua distribuição. O estudo teve como objetivo, analisar as diferenças entre as populações de H. megacephalus, com base na craniometria investigando se o ambiente interfere na morfologia. Analisamos um total de 142 espécimes oriundos de coleções científicas de mamíferos, do Museu Nacional, Universidade Federal do Rio de Janeiro (MN-UFRJ), Laboratório de Biologia e Parasitologia de Mamíferos Reservatórios Silvestres, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (LBCE-Fiocruz) e Laboratório de Biodiversidade, Universidade Federal de Goiás, Regional Jataí, nos quais foram tomadas 20 medidas craniométricas. A craniometria foi explorada nas análises estatísticas de agrupamento de pares não ponderados com médias aritméticas (UPGMA), variação canônica e análise dos Componentes Principais (PCA). Os resultados encontrados nos levaram a concluir a existência de três grupos craniométricos da espécie de H. megacephalus com tendência a se diferenciarem, por influências geográficas.

Network analysis is a powerful tool that provides us a fruitful framework to describe phenomena related to social, technological, and many other real-world complex systems. In this paper, we present a brief review about complex networks including fundamental quantities, examples of network models, and the essential role of network topology in the investigation of dynamical processes as epidemics, rumor spreading, and synchronization. A quite of advances have been provided in this field, and many other authors also review the main contributions in this area over the years. However, we show an overview from a different perspective. Our aim is to provide basic information to a broad audience and more detailed references for those who would like to learn deeper the topic.

Rumors and information spreading emerge naturally from human-to-human interactions and have a growing impact on our everyday life due to increasing and faster access to information, whether trustworthy or not. A popular mathematical model for spreading rumors, data, or news is the Maki–Thompson model. Mean-field approximations suggested that this model does not have a phase transition, with rumors always reaching a fraction of the population. Conversely, here, we show that a continuous phase transition is present in this model. Moreover, we explore a modified version of the Maki–Thompson model that includes a forgetting mechanism, changing the Markov chain’s nature and allowing us to use a plethora of analytic and numeric methods. Particularly, we characterize the subcritical behavior, where the lifespan of a rumor increases as the spreading rate drops, following a power-law relationship. Our findings show that the dynamic behavior of rumor models is much richer than shown in previous investigations.

Species distributions are affected by landscape structure at different spatial scales. Here we study how the interplay between dispersal at different spatial scales and landscape connectivity and composition affect local species dynamics. Using a host-parasitoid model, we assessed host density and host occupancy on the landscape, under different parasitoid dispersal ranges and three local distributions of non-crop habitats, areas where hosts are unable to grow but parasitoids are provided with alternative hosts and food resources. Our results show distinct responses of host density to increases in non-crop area, measured by differences in slopes for different distributions of non-crop habitats, and that the effect of local landscape composition on species dynamics depends on the landscape connectivity at the regional scale. Moreover, we show how host density and occupancy are affected by increasing parasitoid dispersal ranges depending on landscape structure. Our results demonstrate the role of local and regional scales on species distributions and the importance of the combined effects of species biological parameters and landscape structure on species dynamics. Finally, we highlight the relevance of these aspects for the development of better strategies of biological control.

Aims. In this work, we aim to achieve the first laboratory detection of acetohydroxamic acid (CH3CONHOH), a relevant glycine isomer, to enable its eventual identification in the ISM. Methods. We employed a battery of state-of-the-art rotational spectroscopic techniques in the time domain to measure the microwave spectrum of acetohydroxamic acid. We then used the spectral GOTHAM survey performed with the Green Bank Telescope (GBT) to search for the lowest-energy Z-conformer toward the cold and quiescent molecular cloud TMC-1. We also employed a sensitive spectral survey of the chemically rich Galactic Center molecular cloud G+0.693-0.027, based on IRAM 30 m and Yebes 40 m observations. Results. We report direct experimental frequencies of the ground state of acetohydroxamic acid (up to 40 GHz). The 14N nuclear quadrupole hyperfine structure and the A-E splittings due to the internal rotation were observed and analyzed. Hence, a precise set of the rotational spectroscopic parameters were determined for the two distinct conformers, Z- and E-acetohydroxamic acid, which is the initial and prerequisite step of their radio astronomical search in the ISM using low-frequency surveys. We report the nondetection of acetohydroxamic acid toward both astronomical sources. We derive an upper limit to the column density of this molecule very similar to that obtained for glycine. Its corresponding molecular abundance with respect to molecular hydrogen is found to be ≤1 × 10−9 and 2 × 10−10 in TMC-1 and G+0.693-0.027, respectively, which further constrain the abundance of this glycine isomer in the ISM.

One of the most effective space of colonial domination has always been language. In the case of the Portuguese colonialism, it was exclusively through the Portuguese language that a black African could be considered as a cidadão or an indigena, according to discriminatory laws (which were being changed through the times until reaching the so-called “Portuguese Indigenous Statue in Guinea, Angola and Mozambique”, 1954). The Portuguese language was therefore the only linguistic vehicle of citizenship, thus restricting the use of ethnic languages – considered, in a demeaning way, dialects – in formal and official public spaces. This situation has been extended to the linguistic policies of the postcolonial States. The present paper aims to reflect on this colonial heritage, by revealing the meanderings of the epistemology of decolonization and on the conditions of language awareness of the power relations among different languages in Africa (European and native), mainly in the five African Portuguese-speaking countries.

Dynamical systems running on the top of complex networks have been extensively investigated for decades. But this topic still remains among the most relevant issues in complex network theory due to its range of applicability. The contact process (CP) and the susceptible-infected-susceptible (SIS) model are used quite often to describe epidemic dynamics. Despite their simplicity, these models are robust to predict the kernel of real situations. In this work, we review concisely both processes that are well-known and very applied examples of models that exhibit absorbing-state phase transitions. In the epidemic scenario, individuals can be infected or susceptible. A phase transition between a disease-free (absorbing) state and an active stationary phase (where a fraction of the population is infected) are separated by an epidemic threshold. For the SIS model, the central issue is to determine this epidemic threshold on heterogeneous networks. For the CP model, the main interest is to relate critical exponents with statistical properties of the network.

Neste trabalho apresentamos a resenha do livro O que é vida? de Erwin Schrödinger, escrito há quase 80 anos. Sua leitura nos permite uma experiência única de apreciar como um dos maiores físicos do século XX levantava suas questões e como buscava soluções das mesmas. A interdisciplinaridade é uma característica da obra. O leitor será apresentado a conteúdos de física, química, biologia, filosofia, religião, entre outros. Os temas abordados na obra foram, e continuam sendo, de grande importância para o desenvolvimento da ciência. Esse é mais um dos motivos para considerar sua leitura extremamente atual. Com esta resenha, esperamos auxiliar a leitura dessa obra atemporal.

La Administración Armónica es una herramienta administrativa que contempla dos variables; el He rules que es la parte humana de la organización considerando a las personas, recompensas y toma de decisiones; y el Xie rules que se enfoca en la parte material reconociendo la estructura, tareas e información. Esta investigación contempla las variables antes mencionadas con la finalidad de medir el impacto que tienen en el compromiso organizacional medido por el compromiso afectivo, normativo y de recompensa. La población objeto de estudio fue el personal administrativo de empresas automotrices del Edo. De Querétaro. Los análisis de correlación demostraron que la administración armónica tiene una relación alta con el compromiso organizacional mostrando un .750, la correlación más baja fue el compromiso de continuidad con el Xie rules en un .269. A partir de estos resultados la empresa desarrollará estrategias que le permitan afianzar el compromiso de los trabajadores hacia la empresa.

Glycolamide is a glycine isomer and also one of the simplest derivatives of acetamide (e.g., one hydrogen atom is replaced with a hydroxyl group), which is a known interstellar molecule. Using a battery of state of the art rotational spectroscopic techniques in the frequency and time domain, around 1500 transitions have been newly assigned. Based on the reliable frequency predictions, we report a radioastronomical search for glycolamide in the well known high-mass star forming region Sgr B2(N) using the ALMA imaging spectral line survey ReMoCA. We also searched for glycolamide toward Sgr B2(N) with the Effelsberg radio telescope. We report the nondetection of glycolamide toward this source with an abundance at least six and five times lower than that of acetamide and glycolaldehyde, respectively. Our astrochemical model suggests that glycolamide may be present in this source at a level just below the upper limit, which was derived from the EMoCA survey. We could also not detect the molecule in the region's extended molecular envelope, which was probed with the Effelsberg telescope. We find an upper limit to its column density that is similar to the column densities obtained earlier for acetamide and glycolaldehyde with the Green Bank Telescope., Comment: The article will be published as a regular paper in Astronomy and Astrophysics (Forthcoming article since 19 May 2020)

Natural killer T (NKT) cells play a central role in the interface between innate and adaptive immunity, and alpha-galactosylceramide was recently shown to be an endogenous antigen for these cells. The source of alpha-galactosylceramide has not yet been determined; however, in vivo degradation of alpha-galactosylceramide involves generation of alpha-psychosine (alpha-galactosylsphingosine). Alpha-psychosine stimulates cytokine release from NKT cells and constitutes an endogenous antigen for these cells. Alpha-psychosine contains a single lipid chain, while most antigens for NKT cells have two lipid chains, and we have investigated if other glycolipids with one lipid chain, derived from know antigens for NKT cells, stimulate cytokine release from NKT cells. Only psychosine variants derived from the most potent NKT cell antigens cause stimulation, and this stimulation occurs in vitro as well as in vivo. Truncated forms of weak antigens for NKT cells are not stimulatory.

Despite the great attention devoted to the study of phase oscillators on complex networks in the last two decades, it remains unclear whether scale-free networks exhibit a nonzero critical coupling strength for the onset of synchronization in the thermodynamic limit. Here, we systematically compare predictions from the heterogeneous degree mean-field (HMF) and the quenched mean-field (QMF) approaches to extensive numerical simulations on large networks. We provide compelling evidence that the critical coupling vanishes as the number of oscillators increases for scale-free networks characterized by a power-law degree distribution with an exponent $2 < \gamma \leq 3$, in line with what has been observed for other dynamical processes in such networks. For $\gamma > 3$, we show that the critical coupling remains finite, in agreement with HMF calculations and highlight phenomenological differences between critical properties of phase oscillators and epidemic models on scale-free networks. Finally, we also discuss at length a key choice when studying synchronization phenomena in complex networks, namely, how to normalize the coupling between oscillators.

Background: Africa has a rich diversity of plant species, which can be considered important sources of new chemical compounds that can be used in the development of novel therapeutic drugs. Objectives: The present study aimed at investigating the antioxidant activity and total phenolic content of extracts obtained from the roots of Phragmanthera glaucocarpa (Peyr.) Balle, a plant used in Angola folk medicine. Methods: The prepared extracts were tested for their antioxidant activity using ABTS (2,2’-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid), DPPH (1’,1’-diphenyl-2-picrylhydrazyl), and peroxide value methods. Total phenolics were evaluated by the FolinCiocalteu method. Results: For ABTS, the best EC50 result was obtained with the ethyl acetate fraction (1.06 ± 0.30 mg/mL). For the DPPH method, the methanol extract and aqueous fraction presented the best EC50 results, 0.10 ± 0.01 mg/mL and 0.10 ± 0.00 mg/mL, respectively. The ethyl acetate fraction had the highest phenolic content (280.42 ± 0.15 mg G.A.E. /g of dry extract). The best result for the peroxide reduction value on the eighth day of sunflower oil oxidation was obtained for the aqueous fraction, with 131.40 ± 1.05 meq O2 /g of lipid sample. Conclusions: The results of the present study demonstrate that the roots of the medicinal plant Phragmanthera glaucocarpa (Peyr.) Balle represent a promising source of natural phenolic compounds with antioxidant activity.

For all the amides detected in the interstellar medium (ISM), the corresponding nitriles or isonitriles have also been detected in the ISM, some of which have relatively high abundances. Among the abundant nitriles for which the corresponding amide has not yet been detected is cyanoacetylene (HCCCN), whose amide counterpart is propiolamide (HCCC(O)NH2)., The funding from Ministerio de Ciencia e Innovación (CTQ2016-76393-P and PID2019-111396GB-I00), Czech Science Foundation (GACR, grant 19-25116Y), Junta de Castilla y León (Grants VA077U16 and VA244P20), and European Research Council under the European Union’s Seventh Framework Programme ERC-2013-SyG, Grant Agreement n. 610256 NANOCOSMOS are gratefully acknowledged. E.R.A. thanks Fundación Biofísica Bizkaia (FBB) for a postdoctoral contract. J.C.G. thanks the program Physique et Chimie du Milieu Interstellaire (INSU-CNRS) and the Centre National d’Etudes Spatiales (CNES).

We analyze two alterations of the standard susceptible-infected-susceptible (SIS) dynamics that preserve the central properties of spontaneous healing and infection capacity of a vertex increasing unlimitedly with its degree. All models have the same epidemic thresholds in mean-field theories but depending on the network properties, simulations yield a dual scenario, in which the epidemic thresholds of the modified SIS models can be either dramatically altered or remain unchanged in comparison with the standard dynamics. For uncorrelated synthetic networks having a power-law degree distribution with exponent $\gamma5/2$. Differences are more remarkable for $\gamma>3$ where a finite threshold is found in the modified models in contrast with the vanishing threshold of the original one. This duality is elucidated in terms of epidemic lifespan on star graphs. We verify that the activation of the modified SIS models is triggered in the innermost component of the network given by a $k$-core decomposition for $\gamma3$, the activation in the modified dynamics is collective involving essentially the whole network while it is triggered by hubs in the standard SIS. The duality also appears in the finite-size scaling of the critical quantities where mean-field behaviors are observed for the modified, but not for the original dynamics. Our results feed the discussions about the most proper conceptions of epidemic models to describe real systems and the choices of the most suitable theoretical approaches to deal with these models., Comment: 13 pages, 8 figures

The steric effects imposed by the isopropyl group of valine in the conformational stabilization of the capped dipeptide N-acetyl-l-valinamide (Ac-Val-NH

Chemical investigation of Croton gratissimus led to the isolation of fourteen compounds, and their structures were identified to be caryophyllene oxide (1), 1β-methoxycaryolan-9β-ol (2), kaur-16-en-19-oic acid (3), cis-ozic acid (4), spathulenol (5), lupeol (6), 7δ-methoxyopposit-4(15)-en-1β-ol (7), germacra-4(15),5,10(14)-trien-1β-ol (8), β-sitosterol (9), ent-kaur-16-en-18-ol (10), 15-methoxy-neo-clerodan-3,13-dien-16,15-olide-18-oic acid (11), 6α-methoxyeudesm-4(15)-en-1β-ol (12), sucrose (13) and N-methyl-trans-4-hydroxy-L-proline (14) on the basis of 1D and 2D-NMR spectra. This is the first report on the occurrence of compounds (2), (4), (7), (9-12, 14) in the genus Croton.

Teachers’ social networks can play an important role in teacher learning and organizational change. But what influences teachers’ networks? Why do some teachers have networks that are likely to support individual and organizational change, while others do not? This study is a first step in answering this question. We focus on how district policy influences the quality and configuration of teachers’ social networks. We draw on a longitudinal, qualitative study of implementation of a mathematics curriculum in four schools. We show that district policy (1) shaped the tie formation process, influencing the structure of networks; (2) mobilized resources that teachers subsequently accessed via their networks, influencing the benefits accrued through network exchanges; and (3) introduced interaction routines that interrupted conventional ways that teachers talked together. We thus uncover heretofore unexplored facets of network formation and change. We also provide insight into dimensions of social networks that are amenable to outside intervention.

Adaptive optics (AO) is necessary to correct aberrations when imaging the mouse eye with high numerical aperture. In order to obtain cellular resolution, we have implemented wavefront sensorless adaptive optics for in vivo fluorescence imaging of mouse retina. Our approach includes a lens-based system and MEMS deformable mirror for aberration correction. The AO system was constructed with a reflectance channel for structural images and fluorescence channel for functional images. The structural imaging was used in real-time for navigation on the retina using landmarks such as blood vessels. We have also implemented a tunable liquid lens to select the retinal layer of interest at which to perform the optimization. At the desired location on the mouse retina, the optimization algorithm used the fluorescence image data to drive a modal hill-climbing algorithm using an intensity or sharpness image quality metric. The optimization requires ~30 seconds to complete a search up to the 20th Zernike mode. In this report, we have demonstrated the AO performance for high-resolution images of the capillaries in a fluorescence angiography. We have also made progress on an approach to AO with pupil segmentation as a possible sensorless technique suitable for small animal retinal imaging. Pupil segmentation AO was implemented on the same ophthalmic system and imaging performance was demonstrated on fluorescent beads with induced aberrations.

The comprehension of tumor growth is a intriguing subject for scientists. New researches has been constantly required to better understand the complexity of this phenomenon. In this paper, we pursue a physical description that account for some experimental facts involving avascular tumor growth. We have proposed an explanation of some phenomenological (macroscopic) aspects of tumor, as the spatial form and the way it growths, from a individual-level (microscopic) formulation. The model proposed here is based on a simple principle: competitive interaction between the cells dependent on their mutual distances. As a result, we reproduce many empirical evidences observed in real tumors, as exponential growth in their early stages followed by a power law growth. The model also reproduces the fractal space distribution of tumor cells and the universal behavior presented in animals and tumor growth, conform reported by West, Guiot {\it et. al.}\cite{West2001,Guiot2003}. The results suggest that the universal similarity between tumor and animal growth comes from the fact that both are described by the same growth equation - the Bertalanffy-Richards model - even they does not necessarily share the same biophysical properties.

Summary. An atypical strain of Microsporum canis isolated from a two-year-old boy with tinea corporis is described. When cultured on Lactrit-mel agar the strain presented the typical pigment of M. canis without developing characteristic mac-roconidia. After 6 weeks, scarce, rudimentary, fusiform macroconidia 120–150 μm long developed on Lactritmel and Sablac microcultures. In vitro, the strain developed hair perforating organs. Experimental inoculation of a healthy volunteer produced a tinea with typical fluorescence and endoectothrix attack. After isolation the strain remained stable. These results differ from the results reported by English and Tucker. This is the first atypical strain of M. canis reported in Venezuela. Zusammenfassung. Von einem zwei Jahre alten Jungen mit Tinea corporis wurde auf Lac-tritmel-Agar ein Dermatophyt isoliert, der das typische Pigment von Microsporum canis zeigte, ohne die fur diesen Pilz typischen Makrokonidien zu bilden. In Mikrokulturen auf Lactritmel- und Sablac-Agar konnte erst nach sechs Wochen die Bildung von sparlichen, rudimentaren fusiformen Makrokonidien (120–150 μm lang) beobachtet werden. Auf Haare geimpft, bildete das Isolat die fur M. canis charakteristischen Perforations-Organe. Bei einer freiwilligen Versuchsperson erzeugte der Stamm nach experimenteller Infektion eine Tinea corporis mit typischem endo-ektothrichem Befall und Fluoreszenz. Die morphologischen Eigenschaften des Isolates blieben in der Subkultur stabil. Diese Ergebnisse weichen von denen von English und Tucker berichteten ab. Es handelt sich hier um das erste atypische M. canis-Isolat, von dem in Venezuela berichtet wird.

We investigate the dynamic relaxation of random walks on temporal networks by focusing in the recently proposed activity driven model [N. Perra, B. Gon, calves, R. Pastor-Satorras, A. Vespignani, Sci. Rep. 2, 469 (2012)]. For realistic activity distributions with a power-law form, we observe the presence of a very slow relaxation dynamics compatible with aging effects. A theoretical description of this processes in achieved by means of a mapping to Bouchaud's trap model. The mapping highlights the profound difference in the dynamics of the random walks according to the value of the exponent gamma in the activity distribution.

The epidemic threshold of the susceptible-infected-susceptible (SIS) dynamics on random networks having a power law degree distribution with exponent $\gamma>3$ has been investigated using different mean-field approaches, which predict different outcomes. We performed extensive simulations in the quasistationary state for a comparison with these mean-field theories. We observed concomitant multiple transitions in individual networks presenting large gaps in the degree distribution and the obtained multiple epidemic thresholds are well described by different mean-field theories. We observed that the transitions involving thresholds which vanishes at the thermodynamic limit involve localized states, in which a vanishing fraction of the network effectively contribute to epidemic activity, whereas an endemic state, with a finite density of infected vertices, occurs at a finite threshold. The multiple transitions are related to the activations of distinct sub-domains of the network, which are not directly connected., Comment: This is a final version that will appear soon in Phys. Rev. E

Recent works have shown that the contact process running on the top of highly heterogeneous random networks is described by the heterogeneous mean-field theory. However, some important aspects such as the transition point and strong corrections to the finite-size scaling observed in simulations are not quantitatively reproduced in this theory. We develop a heterogeneous pair-approximation, the simplest mean-field approach that takes into account dynamical correlations, for the contact process. The transition points obtained in this theory are in very good agreement with simulations. The proximity with a simple homogeneous pair-approximation is elicited showing that the transition point in successive homogeneous cluster approximations moves away from the simulation results. We show that the critical exponents of the heterogeneous pair-approximation in the infinite-size limit are the same as those of the one-vertex theory. However, excellent matches with simulations, for a wide range of network sizes, are obtained when the sub-leading finite-size corrections given by the new theory are explicitly taken into account. The present approach can be suited to dynamical processes on networks in general providing a profitable strategy to analytically assess and fine-tune theoretical corrections.

Oropharyngeal candidiasis caused by various species of Candida is one of the most common infections in HIV seropositive or AIDS patients. Drug resistance among these yeasts is an increasing problem. We studied the frequency of resistance profile to fluconazole, itraconazole, ketoconazole, amphotericin B and terbinafine of 137 isolates of Candida sp. From HIV positive or AIDS patients with oropharyngeal candidiasis at Instituto de Inmunologia, U.C.V. and the Hospital “Jose Ignacio Baldo”, Caracas Venezuela, using the well diffusion susceptibility test (Magaldi et al.). We found that nearly 10% of C. albicans isolates were primarily fluconazole resistant, 45% of C. albicans isolates from patients with previous treatment were resistant to fluconazole, of which 93% showed cross-resistance to itraconazole, and even about 30% of C. tropicalis (n = 13) were resistant to fluconazole and/or itraconazole. To this respect, several recent reports have been described antifungal cross-resistance among azoles. Therefore, we consider that C. tropicalis should be added to the growing list of yeast in which antifungal drug resistance is common. This report could be useful for therapeutic aspect in AIDS patients with oral candidiasis.

We investigate the effects of local population structure in reaction-diffusion processes representing a contact process (CP) on metapopulations represented as complex networks. Considering a model in which the nodes of a large scale network represent local populations defined in terms of a homogeneous graph, we show by means of extensive numerical simulations that the critical properties of the reaction-diffusion system are independent of the local population structure, even when this one is given by a ordered linear chain. This independence is confirmed by the perfect matching between numerical critical exponents and the results from a heterogeneous mean field theory suited, in principle, to describe situations of local homogeneous mixing. The analysis of several variations of the reaction-diffusion process allow to conclude the independence from population structure of the critical properties of CP-like models on metapopulations, and thus of the universality of the reaction-diffusion description of this kind of models., Comment: 8 pages, 5 figures

This study investigated the bacterial profile of leg ulcers in 52 patients attending the Fremantle Hospital leg ulcer clinic. The aim was to identify whether the presence of specific bacterial groups delays healing, whether the bacterial flora changes as ulcers heal and, if so, whether these changes influence healing. The results show that the presence of any one specific bacterial group did not appear to delay healing, although the presence of four or more bacterial groups was associated with delayed healing. This was found to be statistically significant. It was noted that the bacterial flora does change as ulcers heal and that these changes were not related to changes in healing, with the exception of skin flora.

Euphorbia conspicua latex was fractionated into triterpenic and irritant fractions I and II. The triterpenic fraction afforded 15 known compounds and a new triterpene, 3β-(E)-cinnamoyleuphorbol. 20-O-Acetyl-3-O-angeloylingenol was isolated from irritant fraction II. The compounds euphol, 3β-acetoxyeupha-8,24-diene, 3β-(E)-cinnamoyleuphorbol and 20-O-Acetyl-3-O-angeloylingenol were evaluated for molluscicidal activity. 20-O-Acetyl-3-O-angeloylingenol presented LC100 value of 1 mg mL-1, equivalent to that of the standard molluscicide niclosamide. Compounds euphol, 3β-acetoxyeupha-8,24-diene and 3β-(E)-cinnamoyleuphorbol showed low molluscicidal activity. Mutagenic assays (Ames test with strains TA 98, 100 and 102) were performed with 3β-(E)-cinnamoyleuphorbol in the presence and absence of metabolic activation (S9 mix). In V79 cells, the cytotoxicity of 3β-(E)-cinnamoyleuphorbol was evaluated using the MTT assay and the genotoxicity was assessed using the cytokinesis-block micronucleus assay (CBMN) with or without S9 mix. Mutagenic or genotoxic activity was not detected, and no significant cytotoxicity was observed for 3β-(E)-cinnamoyleuphorbol at lower doses. O latex de Euphorbia conspicua foi fracionado nas frações triterpênica e irritantes I e II. Da fração triterpênica foram isolados 15 compostos já conhecidos e um novo triterpeno denominado 3β-(E)-cinamoileuforbol. A fração irritante II forneceu o 20-O-acetil-3-O-angeloil-ingenol. A atividade moluscicida dos compostos eufol, 3b-acetoxieufa-8,24-dieno, 3β-(E)-cinamoileuforbol e 20-O-acetil-3-O-angeloil-ingenol foi avaliada. O 20-O-acetil-3-O-angeloil-ingenol apresentou uma LC100 de 1 mg mL-1, a qual foi equivalente ao moluscicida padrão niclosamida. Os compostos eufol, 3b-acetoxieufa-8,24-dieno e 3β-(E)-cinamoileuforbol apresentaram uma fraca atividade moluscicida. O 3β-(E)-cinamoileuforbol foi submetido a testes de mutagenicidade (teste de Ames com TA 98, 100 e 102) na presença e ausência de ativação metabólica (mistura S9). Foram também realizados os ensaios de citotoxicidade (teste MTT) e genotoxicidade (teste dos micronúcleos, CBMN) com e sem mistura S9, em células V79 de Hamster chinês. O 3β-(E)-cinamoileuforbol revelou-se fracamente citotóxico e sem atividade mutagênica ou genotóxica.

The effects of the decoction of Erythrina velutina Willd., Fabaceae, were investigated using the root meristem cells of Allium cepa L., Amaryllidaceae. Ten concentrations of the aqueous extract (0.125 to 1.25%) of this medicinal plant were analyzed at both macroscopic and microscopic levels. All concentrations showed root growth inhibition after 96 h treatment. Although there were no significant differences between the mitotic indexes of any concentration and the control, there were changes in the frequencies of cell stages at three different concentrations. Additionally, the presence of five different cells abnormalities was recorded: chromosome bridging, lagging chromosomes, chromosome fragments, disturbed metaphase and disturbed anaphase. These results suggest inhibitory and genotoxic activity of the decoction of E. velutina on Allium cepa.

CdTe films grown on glass substrates covered by fluorine doped tin oxide by Hot Wall Epitaxy (HWE) were studied through the interface dynamical scaling theory. Direct measures of the dynamical exponent revealed an intrinsically anomalous scaling characterized by a global roughness exponent $\alpha$ distinct from the local one (the Hurst exponent $H$), previously reported [Ferreira \textit{et al}., Appl. Phys. Lett. \textbf{88}, 244103 (2006)]. A variety of scaling behaviors was obtained with varying substrate temperature. In particular, a transition from a intrinsically anomalous scaling regime with $H\ne\alpha1$ at high temperatures was observed. The temperature is a growth parameter that controls both the interface roughness and dynamical scaling exponents. Nonlocal effects are pointed as the factors ruling the anomalous scaling behavior.

Leaf extracts of Euphorbia conspicua (Euphorbiaceae), together with the latex and fractions derived therefrom, were evaluated for their molluscicidal and cercaricidal activities and their toxicities to brine shrimps. Whilst the leaf extracts were inactive against Biomphalaria glabrata, the latex, its triterpenic fraction and irritant fractions I and II exhibited high activities against adult snails with LC90 values of 4.87, 10.55, 0.64 and 0.10 microg/mL, respectively. The latex and its derived fractions were considered lethal to the cercaria of Schistosoma mansoni at concentrations of 100 microg/mL. The toxicities of the latex and the irritant fractions, but not of the triterpenic fraction, against Artemia salina were high with LC50 values < 10 microg/mL. The possible application of the latex of E. conspicua as an alternative natural molluscicide is considered.

The rotational spectra of the molecular adducts concerning dimethylether (DME) show interesting features such as: (i) three weak C-H×××O improper H-bonds in the DME-DME dimer [1] and, (ii) the tunnelling splittings of Ar and Ne in the 1:1 complexes with DME [2,3]. Here we report the results of the studies on the interactions of DME with strong proton donors such as H2O, HF and HCl. All of them tunnel between the two lone pairs of the O atom of DME, generating huge inversion splittings in the rotational spectra. From them it has been possible to determine the rates and pathways of the inversion processes. . Millimeter wave absorption free jet and molecular beam Fourier transform microwave spectroscopy techniques have been used for the experiments.DME×××HCl is shown on the figure to the right. HCl is tunnelling from above to below the COC plane with a frequency of 8215.7 MHz. [1] – Y. Tatamitani, B. Liu, J. Shimada, T. Ogata, P. Ottaviani, A. Maris, W. Caminati and J. L. Alonso, J. Am. Chem. Soc., 124 (2002) 2739. [2] – P. Ottaviani, A. Maris, W. Caminati, Y. Tatamitani, Y. Suzuki, T. Ogata and J. L. Alonso, Chem. Phys. Letters, 361 (2002) 341. [3] – A. Maris and W. Caminati, J. Chem. Phys., 118 (2003) 1649.

In the last five years, as HAART has become standard therapy in HIV seropositive or AIDS patients, changes have been noted in the numbers and types of opportunistic fungal infections in these cohorts of patients. Particularly, oropharyngeal candidiasis have become rare in HIV infected patients since the introduction of new anti-HIV drugs of the protease inhibitors type. At the Immunology Institute of the Universidad Central de Venezuela the most frequent protease inhibitors (PIs) used for the treatment of these patients have been: Nelfinavir (Viracept, Roche), Indinavir (Crixivan Merck), Ritonavir (Norvir, Abbott), Saquinavir (Fortovase, Roche). Recently, we observed that recurrent candidiasis was less frequent and no Candida could be isolated in our patients. A direct relation to the PIs was suspected. In order to assess the "in vitro" antifungal activity of the afore mentioned protease inhibitors on Candida sp., we used both the well diffusion test and the NCCLS broth microdilution test to assay 100 Candida sp. isolates from HIV seropositive or AIDS patients with syntomatic oropharyngeal Candida infection. In general, the data obtained with the well diffusion test were in agreement with those obtained by the broth microdilution test. All 100 isolates were susceptible to Saquinavir and 32 were susceptible to Indinavir using the NCCLS microdilution test, while 97 were susceptible to Saquinavir and 52 to Indinavir by the well diffusion test. From 17 C. albicans resistant to fluconazole, all were susceptible to Saquinavir by the NCCLS micromethod and 16 by the well diffusion test. Our results showed anticandidal activity "in vitro" of PIs, mainly Saquinavir.

Establishment of Entamoeba histolytica infection is facilitated through macrophage effector disruption by a prostaglandin E2 (PGE2)-mediated mechanism. Infection severity may be measured by weight of abscess formed. Indomethacin (Indo) treatment of infected hamsters reduced abscess weight by 30% at 7 days post-infection presumably by inhibition of PGE2. To explain reductions in abscess development by Indo treatment, we determined liver functionality in Indo-treated or untreated animals, either healthy or infected. Determinations of serum glutamic oxaloacetic (SGOT) and glutamic pyruvic (SGPT) transaminases, serum alkaline phosphatase (SAP), total serum protein (TSP), and bilirubinemia were done. SGOT, SGPT, and SAP activities showed a significant increase in their values by 600% at seven days post-infection in infected animals in both conditions; nonstatistical differences were found between animals treated or not. This increase did not correlate with the percentage of damage. Infected nontreated hamsters showed TSP levels 30% below normal group (P0.05). Infected Indo-treated hamsters had no significant differences compared to normal values. Infected nontreated animals showed an increase in bilirubin, particularly in indirect bilirubin, whereas infected Indo-treated hamsters showed total bilirubin values lower than normals (P0.05), with a decrease in direct bilirubin levels. Our results demonstrated that E. histolytica infection in hamsters produces similar abnormalities in liver function as it does in humans, and that the beneficial effect of Indo treatment on amoebic abscess development is not related with an improvement of liver functionality.