On the turbulent mixing and ozone variations around the tropical tropopause associated with Kelvin waves

The observed variations of ozone around the tropical tropopause layer in relation to large-scale waves both in the altitude and isentropic coordinates were examined by analyzing ozonesondes provided by SHADOZ (Southern Hemisphere Additional Ozonesondes). Because ozone near this level can be used for the tracer of atmospheric motion, we regarded an ozone enhancement as the signal of a turbulent mixing. Focusing on the vertical fine structure of ozone and temperature, this study presents observed variations of 10 stations near the equator. Based on the signals of Kelvin waves (an eastward-traveling component of equatorial waves) which is filtered in the spectral-frequency domain using reanalysis data (ERA-Interim), we clarified the dependency of the observed profiles to phase evolution of the large-scale wave. The details of relationships between ozone variations and waves will be presented in this poster

Influence of Filler Dispersion on Mechanical Behavior with Large-Scale Coarse-Grained Molecular Dynamics Simulation

Filler morphology impact the physical properties of filled rubber. Two large-scale coarse-grained models containing 1,000 filler particles and 20,000,000 polymer beads were created and coarse-grained molecular dynamics simulations based on Kremer-Grest model were carried out in order to investigate a relationship between filler morphology and mechanical behavior. One is an aggregated model including a non-homogeneous filler distribution which is determined by TEM image analysis, and the other is a uniformity arranged model in which filler particles are distributed in lattice pattern. Comparing stress-strain curves of both models under cyclic deformation stretching to Lambda = 2.0, we confirmed that effects of filler morphology observed in experimental results were reproduced qualitatively by our simulations. The effects of filler morphology are differences of mechanical behavior, modulus and hysteresis of the aggregated model are greater than the uniformity arranged model and that remains in subsequent cycles. Analyzing stresses of both models, we found the differences are mainly attributed to filler stress induced during deformation. Fillers are to be contacted with another adjacent filler particle during deformation and filler stress grows when fillers are aggregated. In addition, differences in contact direction of fillers between loading and unloading increase hysteresis of the aggregated model. Breakage of filler aggregate due to the contacts between fillers in the 1st loading causes stress-softening as contact force and area decrease. We focused on changes of length of polymer-paths bridging filler particles and measured those in the uniformity arranged model in order to study a origin of stress which result from polymer chains dynamics. It was found that polymer-paths become longer to adjust the increase of filler-filler distance particularly in the 1st loading, and the change of polymer-paths in subsequent cycles are lesser than the 1st loading. This irreversible change of polymer network causes hysteresis and stress-softening derived from polymer dynamics

Wetting and contact-line effects for spherical and cylindrical droplets on graphene layers: A comparative molecular-dynamics investigation

In Molecular Dynamics (MD) simulations, interactions between water molecules and graphitic surfaces are often modeled as a simple Lennard-Jones potential between oxygen and carbon atoms. A possible method for tuning this parameter consists of simulating a water nanodroplet on a flat graphitic surface, measuring the equilibrium contact angle, extrapolating it to the limit of a macroscopic droplet and finally matching this quantity to experimental results. Considering recent evidence demonstrating that the contact angle of water on a graphitic plane is much higher than what was previously reported, we estimate the oxygen-carbon interaction for the recent SPC/Fwwater model. Results indicate a value of about 0.2 kJ/mol, much lower than previous estimations. We then perform simulations of cylindrical water filaments on graphitic surfaces, in order to compare and correlate contact angles resulting from these two different systems. Results suggest that modified Young's equation does not describe the relation between contact angle and drop size in the case of extremely small systems and that contributions different from the one deriving from contact line tension should be taken into account.Comment: To be published on Physical Review E (http://pre.aps.org/

Modelling the microstructure and the viscoelastic behaviour of carbon black filled rubber materials from 3D simulations

International audienceVolume fraction and spatial repartition of fillers impact the physical properties of rubber. Extended percolating networks of nano-sized fillers significantly modify the macroscopic mechanical properties of rubbers. Random models that describe the multiscale microstructure of rubber and efficient Fourier-based numerical algorithms are combined to predict the material’s mechanical properties. From TEM image analysis, various types of multiscale models were proposed and validated, accounting for the non-homogeneous distribution of fillers: in the present work, aggregates are located outside of an exclusion polymer simulated by two families of random models. The first model generates the exclusion polymer by a Boolean model of spheres. In the second model, the exclusion polymer is a mosaic model built from a Johnson-Mehl tessellation. Here the exclusion polymer and the polymer containing the filler show a similar morphology, contrary to the Boolean model. Aggregates are then described as the intersection of a Boolean model of spheres and of the complementary of the exclusion polymer. Carbon black particles are simulated by a Cox model of spheres in the aggregates. The models rely on a limited number of parameters fitted from experimental covariance and cumulative granulometry. The influence of the model parameters on percolation properties of the models is studied numerically from 3D simulations. Finally, a novel Fourier-based algorithm is proposed to estimate the viscoelastic properties of linear heterogeneous media, in the harmonic regime. The method is compared to analytical results and to a different, time-discretized FFT scheme. As shown in this work, the proposed numerical method is efficient for computing the viscoelastic response of microstructures containing rubbers and fillers

Caracterização do efeito de substâncias naturais extraídas de macroalgas marinhas e de um painel de substâncias sintéticas na inibição da infecção pelo virus da dengue em modelo in vitro

Orientadora : Drª. Claudia Nunes Duarte dos SantosCo-orientador : Dr. Juliano BordignonTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Biologia Celular e Molecular. Defesa: Curitiba, 25/02/2014Inclui referênciasÁrea de concentraçãoResumo: A dengue é um problema de saúde pública mundial. Apesar do importante impacto clínico e social, não existem vacinas ou terapias específicas para a prevenção ou o tratamento da infecção pelo vírus da dengue (DENV). Considerando o exposto, a pesquisa pela descoberta de drogas para dengue é de extrema importância. Além disso, extratos naturais de origem marinha podem fornecer estruturas químicas novas e diversas com atividade biológica potente que necessitam ser avaliadas, assim como substâncias químicas sintéticas. Neste estudo foi proposta uma abordagem sem alvo específico para a descoberta de drogas contra dengue, baseado em um novo, rápido e econômico ELISA em célula. O in situ ELISA foi padronizado e validado para a linhagem celular Huh7.5 infectada com os quatro sorotipos do DENV, entre eles isolados clínicos e cepas adaptadas de laboratório. Análises estatísticas mostraram um valor médio de S/B de 7,2 e fator-Z de 0,62, demonstrando a consistência e segurança do ensaio. Um painel de quinze extratos de algas foi triado com a concentração não tóxica determinada pelos ensaios de MTT e vermelho neutro. Oito extratos de algas foram capazes de reduzir a infecção pelo DENV para pelo menos um sorotipo testado. Quatro extratos (Phaeophyta: Canistrocarpus cervicornis, Padina gymnospora; Rhodophyta: Palisada perforata; Chlorophyta: Caulerpa racemosa) foram escolhidos para uma avaliação mais aprofundada, e estudos de tempo de adição apontam que eles podem atuar em estágios iniciais do ciclo de infecção, como adsorção ou internalização. Além disso, foi realizada a triagem antiviral com 49 substâncias químicas sintéticas, das quais oitos antraquinonas apresentaram atividade anti-dengue em linhagem celular Huh7.5 e foram testadas em culturas de células mononucleares do sangue periférico de doadores humanos saudáveis. Os tratamentos com TAC02, TAC12 e LSF23 foram capazes de diminuir a porcentagem de células infectadas a níveis comparados ao IFN-a 2A, usado como substância referência. Dessa forma, foi apresentado um método confiável, de baixo custo e fácil execução para a triagem de substâncias com atividade anti-DENV, com resultados promissores partindo de produtos naturais e substâncias químicas sintéticas.Abstract: A dengue é um problema de saúde pública mundial. Apesar do importante impacto clínico e social, não existem vacinas ou terapias específicas para a prevenção ou o tratamento da infecção pelo vírus da dengue (DENV). Considerando o exposto, a pesquisa pela descoberta de drogas para dengue é de extrema importância. Além disso, extratos naturais de origem marinha podem fornecer estruturas químicas novas e diversas com atividade biológica potente que necessitam ser avaliadas, assim como substâncias químicas sintéticas. Neste estudo foi proposta uma abordagem sem alvo específico para a descoberta de drogas contra dengue, baseado em um novo, rápido e econômico ELISA em célula. O in situ ELISA foi padronizado e validado para a linhagem celular Huh7.5 infectada com os quatro sorotipos do DENV, entre eles isolados clínicos e cepas adaptadas de laboratório. Análises estatísticas mostraram um valor médio de S/B de 7,2 e fator-Z de 0,62, demonstrando a consistência e segurança do ensaio. Um painel de quinze extratos de algas foi triado com a concentração não tóxica determinada pelos ensaios de MTT e vermelho neutro. Oito extratos de algas foram capazes de reduzir a infecção pelo DENV para pelo menos um sorotipo testado. Quatro extratos (Phaeophyta: Canistrocarpus cervicornis, Padina gymnospora; Rhodophyta: Palisada perforata; Chlorophyta: Caulerpa racemosa) foram escolhidos para uma avaliação mais aprofundada, e estudos de tempo de adição apontam que eles podem atuar em estágios iniciais do ciclo de infecção, como adsorção ou internalização. Além disso, foi realizada a triagem antiviral com 49 substâncias químicas sintéticas, das quais oitos antraquinonas apresentaram atividade anti-dengue em linhagem celular Huh7.5 e foram testadas em culturas de células mononucleares do sangue periférico de doadores humanos saudáveis. Os tratamentos com TAC02, TAC12 e LSF23 foram capazes de diminuir a porcentagem de células infectadas a níveis comparados ao IFN-a 2A, usado como substância referência. Dessa forma, foi apresentado um método confiável, de baixo custo e fácil execução para a triagem de substâncias com atividade anti-DENV, com resultados promissores partindo de produtos naturais e substâncias químicas sintéticas

Λέοντες, Γρύπες, Σφίγγες στις σφραγίδες και στα σφραγίσματα κατά την ΜΜII- ΥΜ/ΥΕ ΙΙΙ περίοδο. Συνθέσεις - Σχήματα- Υλικά

Ο σκοπός της παρούσας διατριβής ήταν　να εξετάσει τα τρία θέματα, του λέοντα, του γρύπα και της σφίγγας, στις σφραγίδες και τα σφραγίσματα του Αιγαιακού χώρου εικονογραφικά μεν, όμως όχι ως προς τους ρυθμούς (στυλ), αλλά ως προς την στάση και την τοποθέτηση των τριών θεμάτων πάνω στη σφραγιστική επιφάνεια, καθώς και τις συνθέσεις που προκύπτουν από τους συνδυασμούς τους με άλλα θέματα, όπως άλλα ζώα, ανθρώπινες μορφές, παραπληρωματικά και συμβολικά θέματα. Τα ζητήματα αυτά εξετάσθηκαν　σε συσχετισμό με τα σχήματα των σφραγίδων και τα υλικά κατασκευής τους μέσα στο γεωγραφικό πλαίσιο του αιγαιακού κόσμου και στην εξέλιξη που παρατηρείται μεταξύ των ΜΜΙΙ/III χρόνων, όταν τα σκληρά πετρώματα αρχίζουν να χρησιμοποιούνται για την κατασκευή σφραγίδων, και μέχρι την ΥΧ ΙΙΙ περίοδο. Με αυτή την προσέγγιση ευελπιστούμε να καλύψουμε το κενό που υπάρχει στην έρευνα και που αφορά στην σχέση ανάμεσα στις παραστάσεις και στην χρήση των υλικών κατασκευής των σφραγίδων, που είναι οι λίθοι, ορισμένα μέταλλα και η υαλόμαζα. Η μελέτη αυτή επιχειρεί, επίσης, τον εντοπισμό της πιθανής σχέσης μεταξύ της χρήσης συγκεκριμένων υλικών για συγκεκριμένες παραστάσεις. Από τα παραπάνω, προκύπτουν ερωτήματα που αφορούν την οικονομική και κοινωνική θέση των ιδιοκτητών των σφραγίδων, αλλά και γενικότερα ζητήματα που αφορούν την ιδεολογία και τη θρησκεία στον αιγαιακό χώρο, προς την απάντηση των οποίων ευελπιστούμε να έχουμε συμβάλλει. Για να ανταποκριθούμε στους στόχους μας, καταγράφηκαν συνολικά οκτακόσιες εξήντα τρεις σφραγίδες και σφραγίσματα με τα εν λόγω θέματα, που τοποθετούνται από τη ΜΜ ΙΙ-ΙΙΙ έως την ΥΧ ΙΙΙ. Για να συγκρίνουμε και να κατατάξουμε τις σφραγίδες και τα σφραγίσματα με τα θέματα του λέοντα, του γρύπα και της σφίγγας, ορίσαμε ότι οι σφραγίδες και τα σφραγίσματα, θα εξετασθούν σε τρεις άξονες: Παραστάσεις, Στάσεις, Συνθέσεις. Με βάση τις ταξινομήσεις καταλήξαμε στις παρακάτω διαπιστώσεις και απόψεις. Σε ό,τι αφορά στην απόδοση των θεμάτων, όπως η κλίση του λαιμού/κεφαλιού και η κατεύθυνση του κεφαλιού, υποθέτουμε ότι σχετίζεται κυρίως με τα εργαστήρια. Τα εργαστήρια μάλλον θα είχαν ένα «ρεπερτόριο» θεμάτων και σε αυτά έκαναν παραλλαγές ανάλογα με τις ανάγκες και/ή με τις παραγγελίες. Επί πλέον, ανάλογα με την χρονολογική αλλαγή, προτιμώνται οι πιο δραματικές απεικονίσεις, το λυγισμένο σώμα, λαιμός και κεφάλι. Όσον αφορά στο πρόβλημα ότι μία παράσταση π.χ. «επίθεση λέοντα/γρύπα σε άλλο ζώο», απεικονίζεται με διαφορετικές συνθέσεις, ωστόσο εμφανίζονται διαφορετικά σχέδια, υποθέτουμε ότι έχει σχέση με τον σκοπό ή τους ιδιοκτήτες των σφραγίδων. Πρώτον, θεωρούμε ότι μια ομάδα συνθέσεων, που παρουσιάζουν παρόμοιο σχέδιο, θα είχε χρησιμοποιηθεί για τον ίδιο σκοπό. Δεύτερον, ότι συμβολίζει μια ιδιαίτερη ομάδα ανθρώπων, κοινωνική ή θρησκευτική, που κατέχει ηγεμονική θέση. Επί πλέον, αν και αυτή η υπόθεση είναι ασταθής, το ότι μία παράσταση απεικονίζεται σε διαφορετικές συνθέσεις, υποθέτω ότι έχει σχέση με τον σκοπό και τη χρήση των σφραγίδων, με τους ιδιοκτήτες τους ή με δύο είδη εργαστηρίων τα οποία εφάρμοζαν διαφορετικές τεχνικές κατασκευής (χειροκίνητο ή περιστρεφόμενο τρυπάνι). Επειδή συναντώνται ανάλογα με το γεωγραφικό πλαίσιο και με τα υλικά κατασκευής, φαίνεται ότι αυτός ο διαχωρισμός δεν είναι τυχαίος. Μπορούμε να υποθέσουμε ότι αυτά τα δύο είδη εργαστηρίων δεν ήταν εντελώς ανεξάρτητα, αλλά ότι είχαν επαφές, επειδή εντοπίζονται πολλά κοινά εικονογραφικά στοιχεία μεταξύ τους. Πιθανολογείται η ύπαρξη κάποιου «οδηγού» θεμάτων, που ήταν γενικά αποδεκτός μεταξύ εργαστηρίων ή τεχνιτών σφραγιδογλυφίας. Τέλος, συζητήσαμε ερωτήματα για την χρήση των σφραγίδων και καταλήξαμε σε τρεις πιθανές απόψεις, ότι: (Α) Συμβολίζουν την υψηλή κοινωνική και/ή θρησκευτική θέση του ιδιοκτήτη, (Β) Είναι συμβολικοί φορείς δύναμης, θρησκευτικής ή κοινωνικής, (Γ) Έχουν εμπορική χρήση, ως ετικέτες. Υπέθεσα ότι με αυτές τρεις χρήσεις συνδέεται η αξία της σφραγίδας και ένα κριτήριο για την αξία των σφραγίδων είναι ίσως η ποιότητα της σφραγίδας και το αν παραπέμπει σε μαζική παραγωγή ή όχι. Με τη σύνοψη των δεδομένων της παράστασης, της στάσης, της σύνθεσης, καθώς και των συνδυασμών των τριών θεμάτων μας με τα συμβολικά/παραπληρωματικά θέματα και ανάλογα με την χρονολόγηση, την περιοχή προέλευσης και τα υλικά κατασκευής, φάνηκε ότι υπάρχουν διαφορετικές τάσεις σχετικά με την προτίμηση ανά περιοχή και υλικό. Η παράλληλη διερεύνηση της εικονογραφικής εξέλιξης μας οδήγησε σε υποθέσεις σχετικά με την αξία και τη χρήση των σφραγίδων με τα τρία θέματα και με τη λειτουργία των εργαστηρίων κατασκευής τους. Με βάση αυτά τα αποτελέσματα, υποθέτω ότι υπάρχει δυνατότητα να διακρίνεται η σχέση ανάμεσα στους κατόχους των σφραγίδων και στις παραστάσεις λεόντων και γρυπών με το σχέδιο της σφραγίδας, δηλαδή να αναγνωρίζεται η εικονογραφική τάση της περιοχής.The goal of this doctoral thesis is to study the iconography of three motifs, lions, griffins and sphinxes, on Aegean seals and sealings. However, this study does not refer to styles, but to the poses of the animals, to their placement on seals and to compositions resulting from their combination with other motifs, like animals, human figures, symbolic and complementary motifs. These matters have been examined in relation to the shape and the material of the seal within the geographical frame of the Aegean world and within a chronological range from MM II/III (when the hard-stone seal’s tools came to use) to Late Bronze Age III period. Τhis approach intends to fill a gap in research, that has to do with the relationship between the representation on the seal’s surface and the material used each time, that is stone, certain metals, and glass. It also attempts to find the possible relationship between the use of specific materials for specific representations. The above matters arise the question about the economic and social position of seals owners, but also general matters, like ideology and religion in the Aegean world; Ι hope Ι have contributed to the discussion of these matters. In terms of methodology, I have collected and listed a total of eight hundred sixty-three seals and sealings with the three motifs in question (lion, griffin, sphinx), dated from MM II-II to LH III. These seals and sealings have been examined on three axes: Subjects, Poses, Compositions and classifications have been effectuated. Classification has allowed me to make the following suggestions: For the rendering of motifs, as far as the inclination of the neck/head and the direction of the head are concerned, I have proposed that they are connected mainly with the workshops. Workshops may have had a repertory of motifs, but made variations of them according to needs and/or orders. Moreover, following the chronological change, it seems that more dramatical representations, with animals bending their body, neck and head, were preferred. I have also confronted the question why the same scene, for example “lion/griffin attacks another animal”, is represented in different compositions and show a different design. I have come to the supposition that there is a relationship between the purpose of the seals and their design. First I suppose that a group of compositions, which shows a similar design, must have been used for the same purpose. Second, that a group of compositions symbolize one particular group of people, who have a social or religious hegemonic position. Moreover, although this is merely a speculation, I think that, when a subject is represented in different compositions, there must be a relationship between the purpose and the use of the seals, the seals’ owners or the two kinds of workshops, which were implementing different engraving techniques (with burins or knives for soft stone, with bow lathe for hard stone). As long as the representations of seals and sealings are related to the geographical frame and the seals material, it seems that this separation is not accidental. We can suppose that these two kinds of workshops were not completely independent, but had contacts between them, because it is confirmed that they had many common iconographical elements. Probably, they had something like a guide or a “pattern book” for the seals’ subjects, which was generally accepted among workshops or craftsmen. Finally, I have discussed the problem of the seal’s use and have arrived to three probable conclusions: I) Seals with lions, griffins and sphinxes symbolize a high social and/or religious position of their owner, (II) Seals are a symbolic means of power, social and/or religious, (III) Seals have a commercial use, for labeling goods. I have supposed that these three uses were connected with the value of the seals and that a criterion for their value may be their quality and whether they were the result of mass production or not. The synthetic discussion on subjects, poses, compositions and combinations of the three motifs to others, in relation to the chronology of seals, their materials and the finding areas has led me to the idea that there existed different tendencies according to the region and the material. Equally, the investigation of the iconographical development resulted in suggestions concerning the value and use of the seals with the three motifs of lion, griffin and sphinx and the activity of the workshops that have produced them. These results allow us to discern a relationship among the seal’s owners, the subject (lions, griffins, sphinxes) and the design of seals, namely the iconographical tendency of an area