Simple Chiral Diaminobinaphthyl Dilithium Salts for Intramolecular Catalytic Asymmetric Hydroamination of Amino‐1,3‐dienes

Simple and easily accessible chiral lithium amide salts are reported as efficient (pre)catalysts for the diastereo‐ [up to (E:Z)=92:8] and enantioselective [up to 72% ee (E)] hydroamination/cyclisation of conjugated primary aminodienes. These chiral lithium salts are straightforwardly prepared by in situ combination of an N‐substituted (R)‐(+)‐1,1′‐binaphthyl‐2,2′‐diamine ligand and a commercial methyllithium solution. Information on the solid‐state structure of these salts was obtained by X‐ray analysis of a single crystal.     

A Manifold Learning Approach to Data-Driven Computational Elasticity and Inelasticity

Standard simulation in classical mechanics is based on the use of two very different types of equations. The first one, of axiomatic character, is related to balance laws (momentum, mass, energy,...), whereas the second one consists of models that scientists have extracted from collected, natural or synthetic data. Even if one can be confident on the first type of equations, the second one contains modeling errors. Moreover, this second type of equations remains too particular and often fails in describing new experimental results. The vast majority of existing models lack of generality, and therefore must be constantly adapted or enriched to describe new experimental findings. In this work we propose a new method, able to directly link data to computers in order to perform numerical simulations. These simulations will employ axiomatic, universal laws while minimizing the need of explicit, often phenomenological, models. This technique is based on the use of manifold learning methodologies, that allow to extract the relevant information from large experimental datasets.     

Understanding the Interactions of Guanine Quadruplexes with Peptides as Novel Strategies for Diagnosis or Tuning Biological Functions

Guanine quadruplexes (G4s) are nucleic acid structures exhibiting a complex structural behavior and exerting crucial biological functions in both cells and viruses. The specific interactions of peptides with G4s, as well as an understanding of the factors driving the specific recognition are important for the rational design of both therapeutic and diagnostic agents. In this review, we examine the most important studies dealing with the interactions between G4s and peptides, highlighting the strengths and limitations of current analytic approaches. We also show how the combined use of high-level molecular simulation techniques and experimental spectroscopy is the best avenue to design specifically tuned and selective peptides, thus leading to the control of important biological functions.     

High-performance deep-ultraviolet optics for free-electron lasers

Working with wavelengths shorter than the deep ultraviolet involves the development of dedicated optics for free-electron lasers with devoted coating techniques and characterizations. High-performance deep-ultraviolet optics are specially developed to create low-loss, high-reflectivity dielectric mirrors with long lifetimes in harsh synchrotron radiation environments. In February 2001, lasing at 189.7 nm, the shortest wavelength obtained so far with free-electron-laser oscillators, was obtained at the European Free-electron-laser project at ELETTRA Synchrotron Light Laboratory, Trieste, Italy. In July 2001, 330-mW extracted power at 250 nm was measured with optimized transmission mirrors. Research and development of coatings correlated to lasing performance are reported.     

Data decision diagrams for Promela systems analysis

In this paper, we show how to verify computation tree logic (CTL) properties, using symbolic methods, on systems described in Promela. Symbolic representation is based on data decision diagrams (DDDs) which are n-valued Shared Decision Trees designed to represent dynamic systems with integer domain variables. We describe principal components used for the verification of Promela systems (DDD, representation of Promela programs with DDD, the transposition of the execution of Promela instructions into DDD). Then we compare and contrast our method with the model checker SPIN or classical binary decision diagram (BDD) techniques to highlight as to which system classes SPIN or our tool is more relevant.     

Constitutive equations for orthotropic nonlinear viscoelastic behaviour using a generalized Maxwell model Application to wood material

This paper presents a nonlinear viscoelastic orthotropic constitutive equation applied to wood material. The proposed model takes into account mechanical and mechanosorptive creep via a 3D stress ratio and moisture change rate for a cylindrical orthotropic material. Orthotropic frame is based on the grain direction (L), radial (R) and hoop (T) directions, which are natural wood directions. Particular attention is taken to ensure the model to fulfill the necessary dissipation conditions. It is based on a rheological generalized Maxwell model with two elements in parallel in addition with a single linear spring taking into account the long term response. The proposed model is implemented in the finite element code ABAQUS/Standard^® via a user subroutine UMAT and simple example is shown to demonstrate the capability of the proposed model. Future works would deal with damage and fracture prediction for wooden structures submitted to climate variations and mechanical loading.     

Role of adrenocorticotropic hormone in the development and maintenance of the adrenal cortical vasculature

The adrenal cortex is a highly vascularized endocrine tissue. A dense network of blood capillaries centripetally irrigates the adrenal gland, allowing every endocrine cell to be in contact with an endothelial cell. The pituitary hormone ACTH controls the coordinated development of the vasculature and the endocrine tissue mass. This suggests that paracrine secretions between steroidogenic adrenocytes and capillary endothelial cells participate in the control of adrenocortical homeostasis. Besides its effect on the vascular tone of arteries, ACTH induces the expression of the angiogenic cytokine VEGF-A (vascular endothelial growth factor-A) in primary cultures of adrenocortical cells. This growth factor is a specific mitogen for endothelial cells and is likely to mediate the hormonal control of adrenocortical vascularization through a paracrine mechanism. The newly discovered angiogenic factor EG-VEGF (endocrine-gland-derived vascular endothelial growth factor), the expression of which is restricted to endocrine glands and which is preferentially mitogenic for endocrine tissue-derived endothelial cells, is another candidate mediator of great potential interest.     

Widely tunable continuous-wave mid-infrared radiation (5.5-11 microm) by difference-frequency generation in LiInS2 crystal

The first demonstration, to the best of our knowledge, of continuous-wave (cw) difference-frequency generation (DFG) in LiInS2 crystal is reported. Wide spectral coverage (5.5-11.3 microm) has been obtained with angle and wavelength tuning for type II (eoe) critically phase-matched parametric interaction. The phase-matching conditions in cw DFG have been investigated, which allowed us to improve the Sellmeier parameters by use of a two-pole dispersion equation. An effective nonlinear coefficient deff = 6.9 +/- 0.8 pm/V has been determined at approximately 7 microm relative to the well-known nonlinear coefficient d36 of AgGaS2, which yields a power-conversion efficiency of approximately 12.4 microW/(W2 cm). We evaluated the high-resolution spectral characteristics of the DFG source by recording C2H2 and SO2 spectra.