Ethylene responsive transcription factor ERF109 retards PCD and improves salt tolerance in plant

Semi-quantitative RT-PCR for tobacco VIGS lines of 13 knocked down TFs induced 2 h post oxalic acid treatment (20 mM) as compared to their WT and VIGS line with empty pTRV2 (V2) plants. Amplicon sizes of different genes and primers used are shown in Additional file 5: Table S3. The Nbactin gene was used as the house-keeping control. Gene codes refer to those indicated in Additional file 3: Table S2. (DOCX 684 kb

Analysis of transcriptional response to heat stress in Rhazya stricta

Clusters of assembled transcripts of R. stricta SRA in mature leaves (A5-L8) at different time points of the day (A, morning; F-H, midday & L, dusk). Grey lines indicate expression patterns of individual transcripts in a given cluster. Blue lines indicate overall expression pattern across different transcripts of a given cluster. (PDF 397 kb

High resolution 3D imaging of living cells with sub-optical wavelength phonons

Label-free imaging of living cells below the optical diffraction limit poses great challenges for optical microscopy. Biologically relevant structural information remains below the Rayleigh limit and beyond the reach of conventional microscopes. Super-resolution techniques are typically based on the nonlinear and stochastic response of fluorescent labels which can be toxic and interfere with cell function. In this paper we present, for the first time, imaging of live cells using sub-optical wavelength phonons. The axial imaging resolution of our system is determined by the acoustic wavelength (λa = λprobe/2n) and not on the NA of the optics allowing sub-optical wavelength acoustic sectioning of samples using the time of flight. The transverse resolution is currently limited to the optical spot size. The contrast mechanism is significantly determined by the mechanical properties of the cells and requires no additional contrast agent, stain or label to image the cell structure. The ability to breach the optical diffraction limit to image living cells acoustically promises to bring a new suite of imaging technologies to bear in answering exigent questions in cell biology and biomedicine

Laser applications to the characterization of semiconductor nanostructures : coherent control and spin dynamics of elementary electronical excitations

En utilisant la spectroscopie optique résolue en temps, nous étudions la dynamique des populations ainsi que l'orientation optique des états électroniques excités dans des semiconducteurs sous forme de film minces et de nanostructures. Un premier sujet concerne des matériaux semiconducteurs organiques (Phthalocyanincs) sous forme de couches. Un deuxième travail étudie la dynamique de relaxation de spin des excitons dans un puits quantique (QW) de GaN/AIGaN. Nous appliquons une technique pompe-sonde résolue en temps et spectralement, à l'aide d'une source laser femtoseconde (fs) Ti:Saphir accordable en fréquence. Nous avons mesuré la transmission différentielle (tJT(I)11) en fonction du retard (/) entre la pompe et la sonde pour le Phthalocyanine et le spectre de réflectivité différentielle (tJR(t)/R) pour les deux hélicités possibles de la sonde simultanément pour chaque retard pompe-sonde pour le puits quantique (QW) de GaN/AIGaN.We study the population dynamics and optical orientation of excited electronic states in semiconductors thin films and nanostructures. One subject concems the phthalocyanine (Pc), an organic compound semiconductor, in thin film fonn. A second work studies the spin relaxation dynamics of free excitons in a narrow GaN/AIGaN quantum weIl. We apply a temporally and spectrally resolved femtosecond (fs) pumpand- probe technique using a tuneable Ti: Sapphire laser source. We measured the differential transmission rate (,dT(I)/T) as a function of time delay (t) between the pump and probe pulses for the Pc samples while for the GaN/AI GaN QW we have measured the differential reflectivity spectra (tJR(t)/R) for the two different probe helicities simultaneously at different pump-probe delays

Applications du laser à la caracterisation des nanostructures de semiconducteur,contrôle cohérent et dynamique de spin de excitations électroniques élémentaires

En utilisant la spectroscopie optique résolue en temps, nous étudions la dynamique des populations ainsi que l'orientation optique des états électroniques excités dans des semiconducteurs sous forme de film minces et de nanostructures. Un premier sujet concerne des matériaux semiconducteurs organiques (Phthalocyanincs) sous forme de couches. Un deuxième travail étudie la dynamique de relaxation de spin des excitons dans un puits quantique (QW) de GaN/AIGaN. Nous appliquons une technique pompe-sonde résolue en temps et spectralement, à l'aide d'une source laser femtoseconde (fs) Ti:Saphir accordable en fréquence. Nous avons mesuré la transmission différentielle (tJT(I)11) en fonction du retard (/) entre la pompe et la sonde pour le Phthalocyanine et le spectre de réflectivité différentielle (tJR(t)/R) pour les deux hélicités possibles de la sonde simultanément pour chaque retard pompe-sonde pour le puits quantique (QW) de GaN/AIGaN.We study the population dynamics and optical orientation of excited electronic states in semiconductors thin films and nanostructures. One subject concems the phthalocyanine (Pc), an organic compound semiconductor, in thin film fonn. A second work studies the spin relaxation dynamics of fre excitons in a narrow GaN/AIGaN quantum weIl. We apply a temporally and spectrally resolved femtosecond (fs) pumpand-probe technique using a tuneable Ti: Sapphire laser source. We measured the differential transmission rate (,dT(I)/T) as a function of time delay (t) between the pump and probe pulses for the Pc samples while for the GaN/AI GaN QW we have measured the differential reflectivity spectra (tJR(t)/R) for the two different probe helicities simultaneously at different pump-probe delays

Applications du laser à la caracterisation des nanostructures de semiconducteur,contrôle cohérent et dynamique de spin de excitations électroniques élémentaires

En utilisant la spectroscopie optique résolue en temps, nous étudions la dynamique des populations ainsi que l'orientation optique des états électroniques excités dans des semiconducteurs sous forme de film minces et de nanostructures. Un premier sujet coWe study the population dynamics and optical orientation of excited electronic states in semiconductors thin films and nanostructures. One subject concems the phthalocyanine (Pc), an organic compound semiconductor, in thin film fonn. A second work studie

Remote opto-acoustic probing of single-cell adhesion on metallic surfaces

International audienc

On the origin of the decay of the photocatalytic activity of TiO2 powders ground at high-energy

International audienceThe influence of high-energy grinding on the photocatalytic activity of nanocrystalline titania (TiO2) powders was investigated. Either in gas or in liquid reactions, the photocatalytic activity is observed to decrease with milling time. The structural and surface characterizations showed that the catalytic decrease is not correlated to the milling induced transformation of anatase TiO2 into TiO2 rutile via the high-temperature and high-pressure phase TiO2-II but to the introduction of defects and to the amorphization of the surface of the TiO2 nanocrystals (nc). This has been correlated to the observed change of the photoluminescence properties of the powders. Spectrally resolved photoluminescence (PL) measurements as a function of temperature are sensitive to the well-established transformations of ground anatase TiO2 nc into TiO2 rutile via TiO2-II. For all TiO2 nc in their different modifications, increasing the temperature produces a quenching of the PL intensity that is shown to follow a double activation energy law. These PL measurements first show that the electronic properties are strongly affected by the grinding process. Second, new states are generated in ground TiO2, which have a higher PL quantum efficiency than those of the original TiO2 nc. Thus, new channels of radiative recombination are opened due to defects produced by grinding, especially surface defects due to surface amorphization, and the number of electron−hole pairs, which are responsible for the photocatalytic activity, diminishes