Further reduction of normal forms of formal maps

Further reduction for classical normal forms of formal maps is considered in this note. Based on a recursive formula for computing the transformed map of a formal map under a near identity formal transformation, we develop the concepts of Nth order normal forms and infinite order normal forms for formal maps, and give some sufficient conditions for uniqueness of normal forms of formal maps. To cite this article: D. Wang et al., C. R. Acad. Sci. Paris, Ser. I 343 (2006).     

Carbon nanotube supported PtOx nanoparticles with hybrid chemical states for efficient hydrogen evolution

Efficient electrocatalysts for hydrogen evolution reaction (HER) in alkaline solution are highly required for water splitting.Here we design an ultra-small PtOx...     

Unique normal forms for Hopf-zero vector fields

We consider normal forms of Hopf-zero vector fields in $\text{R}{}^3$. Unique normal forms under conjugacy and orbital equivalence for the generic case are given. To cite this article: G. Chen et al., C. R. Acad. Sci. Paris, Ser. I 336 (2003).     

On the deformation and fracture of porous materials

The constitutive behavior of porous materials (including the yield loci, the void growth rate, the macro stress-strain relation and the strain to localization instability) is examined based on the lower bound approach proposed by the present authors. These results are then compared with the experimental and the finite element results as well as those predicted by Gurson's equations. Emphasis is placed on approaching the real behavior from the upper and the lower bound analysis. Calculation is also made on the influence of void nucleation on the critical strain to instability and a modified strain-controlled nucleation criterion is proposed. Finally the instability and fracture of AISI4340 steel in plane strain tension is examined and comparison is made between theoretical and experimental results.     

Synthesis and anticancer property of one Ce(III) compound based on 5-(2-pyrazinyl)tetrazole-2-acetic acid

Mononuclear [Ce(pztza)₂(H₂O)₆](pztza)·H₂O (1) (pztza = 5-(2-pyrazinyl)tetrazole-2-acetato) has been prepared and characterized by IR, elemental analysis and single-crystal X-ray diffraction. PEG_-5000 (poly(ethyleneglycol_-5000)) coated [Ce(pztza)₂(H₂O)₆](pztza)·H₂O nanoparticles (NPs) can disperse into distilled water. In vitro study on Hela cells shows that Hpztza is nontoxic while [Ce(pztza)₂(H₂O)₆](pztza)·H₂O NPs show high toxicity with half-maximal inhibitory concentration (IC₅₀) of 17 μg/mL (1.93 × 10^?5 M). In addition, such NPs can inhibit the migration of Hela cells effectively.     

Diversity of Chemical Constituents from Saxifraga Montana H.

A thorough phytochemical investigation of the whole plant of Saxifraga montana H. afforded a new glucoside, methyl 6″‐O‐(E)‐p‐hydroxycinnamoxyl‐glucosyringate ( 1 ), and seventeen known natural products, 3‐methyl‐6‐methoxy‐3,4‐dihydroisocoumarin‐8‐O‐β‐D‐glucospyranoside ( 2 ), gallic acid ( 3 ), glucosyringic acid ( 4 ), daphnoretin ( 5 ), chamaejasmoside ( 6 ), myricetin ( 7 ), quercetin ( 8 ), quercetin‐3‐O‐β‐D‐galactopyranoside ( 9 ), quercetin‐3‐O‐α‐L‐arabinoside ( 10 ), quercetin‐3‐O‐β‐D‐glucospyranoside ( 11 ), rutin ( 12 ), quercetin‐3‐O‐β‐D‐glucopyranosyl (6‐1) glucopyranoside ( 13 ), ursolic acid ( 14 ), 5,28‐stigmastadien‐3β‐ol ( 15 ), β‐sitosterol ( 16 ), β‐daucosterin ( 17 ), 6′‐palmitoxyl‐β‐daucosterin ( 18 ). On the basis of various spectroscopic methods, especially intensive 2D‐NMR (COSY, HMQC and HMBC), FAB‐MS and HR‐ESI‐MS techniques, their structures were elucidated.     

A functional feature analysis on diverse protein–protein interactions: application for the prediction of binding affinity

Protein–protein interactions (PPIs) play crucial roles in diverse cellular processes. There are different types of PPIs based on the composition, affinity and whether the association is permanent or transient. Analyzing the diversity of PPIs at the atomic level is crucial for uncovering the key features governing the interactions involved in PPI. A systematic physico-chemical and conformational studies were implemented on interfaces involved in different PPIs, including crystal packing, weak transient heterodimers, weak transient homodimers, strong transient heterodimers and homodimers. The comparative analysis shows that the interfaces tend to be larger, less planar, and more tightly packed with the increase of the interaction strength. Meanwhile the strong interactions undergo greater conformational changes than the weak ones involving main chains as well as side chains. Finally, using 18 features derived from our analysis, we developed a support vector regression model to predict the binding affinity with a promising result, which further demonstrate the reliability of our studies. We believe this study will provide great help in more thorough understanding the mechanism of diverse PPIs.