Dispersion of tubular modes

I show that a theoretical expression for the dispersion (d²β/dω₂) of tubular modes in dispersive multimode square-law fibers coincides with the wave-optics result.     

Carre symetrique d'une forme primitive

A direct proof is given for the functionnal equation satisfied by the primitive symmetric square attached to a newform of any level. The method uses technics of modular forms theory and is based on a carefully study of minimal forms and Atkin-Lehner operators on twisted forms. The root number is explicit thanks to some properties of Gauss sums averaes analogous to Barnes Lemma.     

Late‐Stage Isotopic Carbon Labeling of Pharmaceutically Relevant Cyclic Ureas Directly from CO2

A robust, click‐chemistry‐inspired procedure for radiolabeling of cyclic ureas was developed. This protocol, suitable for all carbon isotopes (¹¹C, ¹³C, ¹⁴C), is based on the direct functionalization of carbon dioxide: the universal building block for carbon radiolabeling. The strategy is operationally simple and reproducible in different radiochemistry centers, exhibits remarkably wide substrate scope with short reaction times, and demonstrates superior reactivity as compared to previously reported systems. With this procedure, a variety of pharmaceuticals and an unprotected peptide were labeled with high radiochemical efficiency.     

Tetrablock Metallopolymer Electrochromes

Multi‐block polymers are highly desirable for their addressable functions that are both unique and complementary among the blocks. With metal‐containing polymers, the goal is even more challenging insofar as the metal properties may considerably extend the materials functions to sensing, catalysis, interaction with metal nanoparticles, and electro‐ or photochrome switching. Ring‐opening metathesis polymerization (ROMP) has become available for the formation of living polymers using highly efficient initiators such as the 3rd generation Grubbs catalyst [RuCl₂(NHC)(=CHPh)(3‐Br‐C₅H₄N)₂], 1 . Among the 24 possibilities to introduce 4 blocks of metallopolymers into a tetrablock metallocopolymer by ROMP using the catalyst 1 , two viable pathways are disclosed. The synthesis, characterization, electrochemistry, electron‐transfer chemistry, and remarkable electrochromic properties of these new nanomaterials are presented.     

Classical theory of laser linewidth

The classical theory of light fluctuations rests on the intuitive concept that jumps between atomic states occur at independent times when the optical field has a prescribed value. The statistical properties of phase-noise sources are obtained in the present paper by applying this principle to detuned atoms. Formulae for amplitude and phase fluctuations coincide with quantum-theory results even when non-classical states of light are generated. Theories employing semiclassical or quantum concepts are reviewed. We consider particularly the linewidth of laser oscillators operating below and above threshold when the atomic polarization cannot be adiabatically eliminated. Quantum-theory results by Lax (1966) are recovered from classical theory in a straightforward manner. More general results are given for dispersive loads, applicable to external-cavity lasers and relevant to gain guidance. It is emphasized that the K-factor as calculated by Petermann is applicable only below threshold. When more than one emitting element is present, population rate equations need to be considered and the linewidth decreases when the pump fluctuations are suppressed. The role of gain compression relating to semiconductor lasers is discussed. It is shown that at low and moderate powers gain compression reduces the effective phase-amplitude coupling factor, . But at high power a number of mechanisms contribute to linewidth rebroadening. One of them is the statistical (quasi-thermal equilibrium) fluctuation of the refractive index. General concepts applicable to broadband light are outlined in an appendix.     

Brownian processes in infinite dimension

LetE be a locally convex space endowed with a centered gaussian measure . We construct a continuousE-valued brownian motionW _t with covariance . The main goal is to solve the SDE of Langevin type dX _t= dW _t–AX _t wherea andA are unbounded operators of the Cameron-Martin space of (E, ). It appears as the unique linear measurable extension of the solution of the classical Cauchy problemv(t)= u–Av(t).     

Mass spectrometric analysis of the interactions between CP12, a chloroplast protein, and metal ions: a possible regulatory role within a PRK/GAPDH/CP12 complex

The small chloroplast protein CP12 plays the role of a protein linker in the assembly process of a PRK/GAPDH/CP12 complex that is involved in CO2 assimilation in photosynthetic organisms. The redox state of CP12 regulates its role as a protein linker. Only the oxidized protein, with two disulfide bonds, is active in complex formation. Several observations indicating that CP12 might bind a metal ion led us to screen the binding of different metal ions on oxidized or reduced CP12 using non-covalent electrospray ionization mass spectrometry (ESI-MS) experiments. The oxidized protein bound specifically Cu2+ and Ni2+ (Kd of 26+/-1 microM and 11+/-1 microM, respectively); other cations such as Fe2+ and Zn2+ did not bind, while cations such as Cd2+ formed non-specific adducts to CP12. Similar results were obtained for metal ions on screening with the reduced CP12. Interestingly, the present results suggest that Cu2+ catalyzes the re-formation of the disulfide bonds of the reduced CP12, leading to recovery of the fully oxidized CP12 that is then able to bind a Cu2+ ion. Finally the high similarity between CP12 and copper chaperones from Arabidopsis thaliana, as judged by hydrophobic cluster analysis, provides additional evidence for the relevance of metal binding for the in vivo situation. The findings that CP12 is able to bind a metal ion, and that Cu2+ catalyzes the oxidation of the thiol groups of CP12, are new characteristics of this protein that may prove to be important in the regulation of the assembly process of the PRK/GAPDH/CP12 complex.     

大豆中Glycinol的分离与鉴定

 Glycinol是大豆中主要的植物抗毒素和植物雌激素glyceollins的直接前体,是研究大豆中异戊烯转移酶必需的重要底物。该研究以新鲜大豆为原料，采用硝酸银诱导大豆子叶使glycinol 在其中累积,再用甲醇提取，经制备高效液相色谱分离获得单一成分;经液相色谱/四极杆-飞行时间串联质谱及紫外光谱鉴定,并与标准品对照,确定所获得的单一成分为glycinol。采用该分离方法可从390 g鲜重的大豆中分离得到100 mg高纯度的glycinol。该研究提供了一种分离纯化和较大量制备glycinol 的方法。