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The inducible proto-oncogenic (c-Fos:c-Jun)/AP-1 transcription complex binds 12-O-tetradecanoylphorbol 13-acetate (TPA)-responsive elements (TRE) in its target genes. It is tightly controlled at multiple levels to avoid the deleterious effects of its inappropriate activation. In particular, SUMOylation represses its transactivation capacity in transient reporter assays using constitutively expressed proteins. This led to the presumption that (c-Fos:c-Jun)/AP-1 SUMOylation would be required to turn-off transcription of its target genes, as proposed for various transcription factors. Instead, thanks to the generation of an antibody specific for SUMO-modified c-Fos, we provide here direct evidence that SUMOylated c-Fos is present on a stably integrated reporter TPA-inducible promoter at the onset of transcriptional activation and colocalizes with RNA polymerase II within chromatin. Interestingly, (c-Fos:c-Jun)/AP-1 SUMOylation limits reporter gene induction, as well as the appearance of active transcription-specific histone marks on its promoter. Moreover, non-SUMOylatable mutant (c-Fos:c-Jun)/AP-1 dimers accumulate to higher levels on their target promoter, suggesting that SUMOylation might facilitate the release of (c-Fos:c-Jun)/AP-1 from promoters. Finally, activation of GADD153, an AP-1 target gene, is also associated with a rapid increase in SUMOylation at the level of its TRE and c-Fos SUMOylation dampens its induction by TPA. Taken together, our data suggest that SUMOylation could serve to buffer transcriptional activation of AP-1 target genes. [ABSTRACT FROM AUTHOR]

We present procedures to develop and characterise chirped multilayer mirrors for attosecond pulses. The design procedure involves a simulated annealing optimisation algorithm to obtain a multilayer structure with the desired performances. The characterisation step requires the use of well-calibrated attosecond and synchrotron beam lines, allowing one to measure the amplitude and phase response of the mirror. We illustrate these approaches with a set of mirrors designed to have zero or negative dispersion. The remarkable agreement between theoretical and experimental performances validates this overall process, and demonstrates the capability of such mirrors to control the temporal profile of attosecond pulses. These tools and techniques for developing attosecond chirped mirrors will facilitate the generalisation of such components on attosecond experiments. [ABSTRACT FROM PUBLISHER]

We report on the study of multilayer mirrors that were designed to compress extreme-ultraviolet pulses below 50 as. The mirrors were optimized in the time domain to obtain the desired pulse shape and duration when combined with a broadband hybrid filter. Moreover, they appeared to be very robust to environmental parameters, ensuring a pulse compression in various conditions. We manufactured the mirrors and characterized them on a synchrotron facility both in amplitude and in phase. A measurement of the latter was carried out using the photocurrent technique, which is the only method that allows one to access the mirrors' absolute spectral phase. This led to a measurement of the offset induced by the mirrors on the carrier-envelope phase of attosecond pulses. [ABSTRACT FROM AUTHOR]

Oral Diseases (2011) (Suppl. 1), 99-104 (i) To define the current state of oral medicine clinical practice internationally, and (ii) to make recommendations for future modeling of the practice of oral medicine. A survey was designed by an international panel of oral medicine experts to assess the current state of oral medicine practice internationally. The survey was sent to oral medicine experts across the world, and responses were electronically stored and analyzed using descriptive statistics. Two hundred respondents completed the survey representing 40 countries from six continents. The two most common settings for an oral medicine practice were in a hospital and a dental school. More than 88% of respondents considered management of oral mucosal disease, salivary dysfunction, oral manifestations of systemic diseases, and facial pain in the definition of oral medicine. (i) Oral medicine clinicians diagnose and manage a wide variety of orofacial conditions; (ii) There are significant differences in the definition of oral medicine clinical practice from country to country; (iii) India has the largest expansion of oral medicine services as defined by escalating numbers of clinicians within the specialty as compared with other countries; (iv) oral medicine practitioners have a wide range of professional responsibilities. [ABSTRACT FROM AUTHOR]

Recent extreme ultraviolet sources using high-harmonic generation in a rare gas make new optics developments necessary. We report on the study and development of multilayer structures with efficient reflectivity in the 35–75 eV energy range. We have optimized, deposited and characterized two aperiodic broadband mirrors consisting of a Mo, Si and B4C thin-film stack. We used the needle procedure in order to optimize mirror reflectivity. The magnetron sputter deposited multilayers have been calibrated and characterized using Cu K α grazing incidence X-ray reflectometry. Reflectivity measured at near-normal incidence on a synchrotron radiation source reaches 12% with a full width at half maximum of nearly 40 eV. Experimental results are compared with theoretical simulation using available optical constants for Mo, Si and B4C in this spectral range. [ABSTRACT FROM AUTHOR]

We report on the development of multilayer optics for the extreme ultra-violet (EUV) range. The optical performance of Al-based multilayer mirrors is discussed with regard to promising reflectivity and selectivity characteristics and the problems of the interfacial roughness for this type of multilayers. We demonstrate a possibility to reduce the average roughness by introducing additional metal layer (W or Mo) rather than depositing a buffer layer at each interface. We have prepared and tested Al/SiC, Al/W/SiC and Al/Mo/SiC multilayers of various periods for the spectral range from 15 to 40 nm, which is the range of increasing interest for high-order harmonic generation, synchrotron radiation and astrophysics. The structure of the three-component systems has been optimized in order to obtain the best reflectivity for each wavelength within the spectral range. We have shown that introduction of refractory metal in Al-based periodic stack can improve the optical performance of multilayer reflecting coatings designed for the EUV applications. [ABSTRACT FROM AUTHOR]

Locally reducing the width of a wide photonic crystal (PhC) waveguide generates a constriction which acts as an internal reflector. We have simulated and measured the spectral behavior of a wide PhC waveguide locally constricted to a narrower PhC waveguide and ended by two cleaved facets, thus generating two coupled cavities. Passive structures as well as electrically injected active structures have been investigated. The multimode behavior of wide PhC waveguides is evidenced to play a deciding role. Modal reflection and transmission at the constriction are simulated and measured on passive PhC waveguides, when varying the constrictions' hole size and length. The spectral behavior of full-PhC electrically pumped lasers including such a constriction is measured and analyzed according to the constriction geometry. Design rules are finally proposed to take advantage of this coupled-cavities behavior for high rejection and high external efficiency monomode laser operation. [ABSTRACT FROM PUBLISHER]

Focuses on the use of a developed spin-polarized electron sources with very high polarization for electron spectroscopy. Data on spin-resolved inverse photoemission form Fe(100) films excited by polarized electrons; Photocathode preparation and characterization.

A spin-polarized electron gun for electron spectroscopies is described in detail. The gun consists of an electron source based on a negative electron affinity GaAs photocathode coupled to an appropriate transport electron optics. The gun has been designed with the aid of ray-tracing analysis and then accurately tested. It produces a transversely polarized (P0∼27%) electron beam at variable energy with a small spot size and angular spread (less than 2 mm and 5°, respectively). Such performances are attained up to sample currents as high as 10 μA for the whole beam energy range (8–50 eV). As an application we present data on spin-dependent absorbed current spectroscopy from bcc Fe films epitaxially grown on Ag(100). [ABSTRACT FROM AUTHOR]

A two-dimensional phenomenological approach previously developed for the modeling of out-of-plane losses in low refractive index contrast planar photonic crystals (PPhCs) is used to study the dependence of the different loss terms on the planar waveguide parameters. It is demonstrated that: (i) Losses can be minimized by designing vertical heterostructures optimized for a given technological process and/or for a given hole shape; and (ii) any small reduction of the loss value has a strong impact on the optical performances of PPhC structures. [ABSTRACT FROM AUTHOR]