Mecanismos de fotosensibilización inducida por fármacos: una visión general

This paper presents a general survey of the mechanisms involved in drug phototoxicity. Moreover, a list of 174 currently used clinical drugs inducing photosensitization is provided in addition to some others from which phototoxic effects are suspected. Likewise, some aspects related to the mechanisms involved in the phototoxicity of fluoroquinolones and non steroidal-antiinflammatory drugs have been reviewed. Finally, a possible role of the arenediazonium ions as photosensitisers is discussed.En el presente trabajo se hace ofrece una visión general los mecanismos relacionados con la fototoxicidad de sustancias farmacológicamente activas. Además se ha confeccionado una lista de 174 compuestos utilizados en la actualidad en la práctica clínica y de los que se existe pruebas de su actividad fototóxica. Conjuntamente se ofrece otra relación con sustancias cuyos efectos fototóxicos se sospechan. Asimismo, se revisan algunos aspectos relacionados con los mecanismos de fotoxicidad de fluoroquinolonas y antiinflamatorios no esteroídicos. Por último, se discute la posible actividad fotosensibilizadora de los iones arenodiazónicos

Infectivity of entomogenous nematodes (Steinernematidae and Heterorhabditidae) to Pediculus humanus capitis De Geer (Anoplura : Pediculidae)

La sensibilité du pou de tête, #Pediculus humanus capitis, aux nématodes entomoparasites #Steinernema rara, #S. feltiae, #Heterorhabditis bacteriophora (souches Oliva et Rio Negro) a été évaluée. Tous ces nématodes (à l'exception de #S. feltiae) tuent les adultes et les nymphes, mais non les oeufs. La souche Rio Negro de #H. bacteriophora et #S. rara se montrent bien plus agressives envers les adultes et les nymphes que les autres nématodes. #H. bacteriophora souche Oliva est plus agressif envers les adultes. La pénétration des larves infestantes a lieu apparemment par les spiracles et le diamètre du corps des larves infestantes constituerait un facteur limitant. Le parasitisme du pou de tête par des nématodes entomoparasites est relaté pour la première fois. (Résumé d'auteur

Instabilities of conducting fluid layers in cylindrical cells under the external forcing of weak magnetic fluids

In this work, we analyze recent results concerning the instabilities created in a layer of liquid metal by the action of time-dependent magnetic fields. The experimental setup allows the characterization of different patterns very close to the threshold. For very low frequencies of the forcing field, the axisymmetric fluid layer destabilizes with different azimuthal wavenumbers. An improved analysis allows the characterization of different patterns for interaction parameter values as low as 5 · 10 −3

Subcritical instabilities in a convective fluid layer under a quasi-one-dimensional heating.

The study and characterization of the diversity of spatiotemporal patterns generated when a rectangular layer of fluid is locally heated beneath its free surface is presented. We focus on the instability of a stationary cellular pattern of wave number ks which undergoes a globally subcritical transition to traveling waves by paritybreaking symmetry. The experimental results show how the emerging traveling mode 2ks /3 switches on a resonant triad ks ,ks /2,2ks /3 within the cellular pattern yielding a “mixed” pattern. The nature of this transition is described quantitatively in terms of the evolution of the fundamental modes by complex demodulation techniques. The Bénard-Marangoni convection accounts for the different dynamics depending on the depth of the fluid layer and on the vertical temperature difference. The existence of a hysteresis cycle has been evaluated quantitatively. When the bifurcation to traveling waves is measured in the vicinity of the codimension-2 bifurcation point, we measure a decrease of the subcritical interval in which the traveling mode becomes unstable. From the traveling wave state the system undergoes a global secondary bifurcation to an alternating pattern which doubles the wavelength ks /2 of the primary cellular pattern; this result compares well with theoretical predictions P. Coullet and G. Iooss, Phys. Rev. Lett. 64, 866 1990 . In this cascade of bifurcations towards a defect dynamics, bistability due to the subcritical behavior of our system is the reason for the coexistence of two different modulated patterns connected by a front. These fronts are stationary for a finite interval of the control parameters

MOLECULAR ANALYSIS OF DOUBLE FERTILIZATION PROCESS IN ARABIDOPSIS

Fertilization and seed formation are key events in the life cycle of flowering plants. The seed represents an elaborated functional unit, whose main purpose is to propagate the plant's offspring. The first step in seed development is the formation of ovules and subsequently the achievement of a successful double fertilization process. In our lab we have discovered that the MADS-box domain protein complex formed by SEEDSTICK (STK) and SEPALLATA3 (SEP3), responsible to maintain ovule identity, have as a direct target a member of the REM family, VERDANDI (VDD, REM20). With the combination of Bio-informatics studies and ChIP-qPCR experiments using specific STK and SEP3 antibodies, we were able to identify REM11, as the second direct target of the STK-SEP3 complex. The phenotype of the rem11 mutant is very similar to the one described for vdd-1/+ demonstrating that REM11 plays a similar function in the fertilization process. To better understand the fertilization defect observed in these mutants we have used a new technique developed to observe fertilization in vivo, by visualizing the gametes with a combination of markers for sperm cells and for the female gamete. In the rem11 or in vdd-1 gametophytes the synergid cell seemed to lose identity. Although the pollen tubes reached the micropyle, the two sperm cells didn\u2019t migrate toward the egg and center cells. These results showed the important and the direct involvement of these two genes in the control of synergid driven processes. Ultimately we discovered that genes responsible for the pollen tube attraction like the transcription factor MYB98, are correctly expressed in the mutants whereas genes, probably responsible for the degeneration process are miss-expressed. In summary, we can say that, two very different processes are regulated by the synergid cells: 1) the attraction of the pollen tube and 2) the synergid degeneration (apoptosis). We discover that the second step is specifically controlled by VDD and REM11, two proteins that by yeast-2-hybrid experiments were able to interact. Based on these results we have decided to study if other REM transcription factors could interact with REM11 and VDD. In conclusion STK-SEP3 MADS-box complex are able to directly regulate a REM transcription factor complex that has a very important and specific role during the double fertilization process. To understand how VDD-REM11 complex regulate synergid degeneration we have performed a RNA sequencing experiment comparing wild-type mature carpels to mutant ones. Exciting targets have been discovered and discuss in this thesis. I have also studied the regulation of VDD transcription by STK-SEP3 complex. In VDD regulatory region three CArG boxes were identified and by Chromatin Imunoprecipitation experiments, we have showed that the ovule identity proteins STK and SEP3 bind to the first and third CArG boxes. We have performed in vivo and in vitro experiments showing that the STK-SEP3 complex is needed to form short-range loops in VDD promoter. For years evidences based on in vitro biochemical assays and yeast experiments shown that MADS box proteins form multimeric complexes. New evidences for the quartet-floral model were obtained, analyzing the activation of VDD promoter by STK-SEP3 multimeric complex. Least but not the last, I have also analyzed the interaction of ARABIDOPSIS BSISTER (ABS) with STK, showing that they have a function in the regulation of the endothelium development, the inner most integument layer of the mature ovule that we demonstrated to be required to the double fertilization process

The Kibble-Zurek mechanism in a subcritical bifurcation

We present the study of the freezing dynamics of topological defects in a subcritical system by testing the Kibble-Zurek (KZ) mechanism while crossing a tri-stable region in a one-dimensional quintic complex Ginzburg-Landau equation. The critical exponents of the KZ mechanism and the horizon (KZ-scaling regime) are predicted from the quasistatic study, and are in full accordance with the quenched study. The correlation length, in the KZ freezing regime, is corroborated from the number of topological defects and from the spatial correlation function of the order parameter. Furthermore, we characterize the dynamics to differentiate three out-of-equilibrium regimes: the adiabatic, the impulse and the free-relaxation. We show that the impulse regime shares a common temporal domain with a fast exponential increase of the order parameter

A LINEAR STUDY OF HIGH-DRAG STATES AND FLOW STAGNATION PRODUCED BY MOUNTAIN WAVES

A linear model of gravity waves generated by stratified airflow over mountains is developed. The model provides simple, closed-form formulas for the surface drag in a situation where conditions for wave resonance exist. The wind is constant near the surface and decreases linearly above. The drag normalized by its value in the absence of shear is found to depend on two parameters: the height of the interface where the shear is discontinuous and the Richardson number, Ri, in the region above. This drag attains maxima when the height of the interface induces constructive interference between the upward and downward propagating reflected waves, and minima when there is destructive interference. The amplitude of the drag modulation becomes larger for lower Ri. It is also shown that, for Ri<2.25, the locations where wave breaking is first predicted to occur in flow over a 2D ridge become displaced horizontally and vertically by an amount depending on Ri

GRAVITY WAVE DRAG PRODUCED BY SMALL AMPLITUDE ELLIPTICAL MOUNTAINS FOR SHEARED WIND PROFILES

The analytical models of Teixeira et al. (2004) and Teixeira and Miranda (2004), where the gravity wave drag exerted by a sheared stratified flow on axisymmetric or 2D mountains is calculated, are extended here to mountains with an elliptical horizontal cross section. For the simple situations considered in this study, the normalized drag depends on only two parameters: the Richardson number at the surface, Ri, and the horizontal aspect ratio of the mountain. For a wind that varies linearly with height, the drag always decreases as Ri decreases, albeit at different rates depending on the aspect ratio. For a wind that rotates with height at a constant rate maintaining its magnitude, the drag generally increases as Ri decreases, but if the mountain is sufficiently elongated in the surface streamwise direction, this dependence changes sign. It is also shown that flow stagnation at the surface is strongly affected by variations of the windspeed with height, but weakly affected by variations of wind direction

European Multidisciplinary and Water-Column Observatory - European Research Infrastructure Consortium (EMSO ERIC): challenges and opportunities for strategic European marine sciences

EMSO (European Multidisciplinary Seafloor and water-column Observatory, www.emso-eu.org) is a large‐scale European Research Infrastructure I. It is a distributed infrastructure of strategically placed, deep‐sea seafloor and water column observatory nodes with the essential scientific objective of real‐time, longterm observation of environmental processes related to the interaction between the geosphere, biosphere, and hydrosphere. The geographic locations of the EMSO observatory nodes represent key sites in European waters, from the Arctic, through the Atlantic and Mediterranean, to the Black Sea (Figure 1), as defined through previous studies performed in FP6 and FP7 EC projects such as ESONET‐CA, ESONET‐NoE, EMSO-PP (Person et al., 2015)Peer Reviewe