Investigations on the Suzuki-Miyaura and Negishi couplings with alkenyl phosphates: application to the synthesis of 1,1-disubstituted alkenes

The development of versatile Suzuki-Miyaura and Negishi cross-couplings with nonactivated alkenyl phosphates and aromatic boronic acids or organozinc reagents was achieved in acceptable to good yields. A series of 1,1-disubstituted alkenes were synthesized using a combination of either Ni(COD)2/Cy3P/K3PO4 or Pd2dba3/DPPF in THF. When working with alkenyl electrophiles in metal-catalyzed cross-couplings, this method lends itself as a less costly and more stable alternative to the corresponding triflate or nonaflate derivatives. In addition, initial studies are presented regarding an efficient 1,2-migration under Negishi coupling conditions.     

Extremal harmonic active control of power for a monocylinder hybrid powertrain

This article presents a real-life application for the extremal harmonic active control of power [1] applied on a hybrid engine setup. The active control was adapted for a hybrid powertrain constituted of a one-cylinder diesel engine coupled with a permanent magnet synchronous machine. The problem was formulated in the harmonic domain and the control objective was to extremalize energetic criterions. Three criterions were considered: minimizing the speed ripple of the engine, maximizing the mechanical reactive power (mechanical impedance adaptation) and maximizing the active electric power for energy harvesting. The results show that, for the first and second orders of the ripple, speed oscillations can be completely cancelled and reactive power and active power can be optimized on-line. The implicit extremal controller converged rapidly, remaining stable even when the mean engine speed changed abruptly. These results confirm the robustness and the applicability of the extremal harmonic active control for industrial applications.     

Time-dependent radiolytic yield of OH• radical studied by picosecond pulse radiolysis

Picosecond pulse radiolysis measurements using a pulse-probe method are performed to measure directly the time-dependent radiolytic yield of the OH(?) radical in pure water. The time-dependent absorbance of OH(?) radical at 263 nm is deduced from the observed signal by subtracting the contribution of the hydrated electron and that of the irradiated empty fused silica cell which presents also a transient absoption. The time-dependent radiolytic yield of OH(?) is obtained by assuming the yield of the hydrated electron at 20 ps equal to 4.2 × 10(-7) mol J(-1) and by assuming the values of the extinction coefficients of e(aq)(-) and OH(?) at 782 nm (ε(λ=782 nm) = 17025 M(-1) cm(-1)) and at 263 nm (ε(λ=263 nm) = 460 M(-1) cm(-1)), respectively. The value of the yield of OH(?) radical at 10 ps is found to be (4.80 ± 0.12) × 10(-7) mol J(-1).     

Deriving robust counterparts of nonlinear uncertain inequalities

Mathematical Programming - In this paper we provide a systematic way to construct the robust counterpart of a nonlinear uncertain inequality that is concave in the uncertain parameters. We use...     

Assessment of two complementary liquid chromatography coupled to high resolution mass spectrometry metabolomics strategies for the screening of anabolic steroid treatment in calves

Anabolic steroids are banned in food producing livestock in Europe. Efficient methods based on mass spectrometry detection have been developed to ensure the control of such veterinary drug residues. Nevertheless, the use of "cocktails" composed of mixtures of low amounts of several substances as well as the synthesis of new compounds of unknown structure prevent efficient prevention. New analytical tools able to detect such abuse are today mandatory. In this context, metabolomics may represent new emerging strategies for investigating the global physiological effects associated to a family of substances and therefore, to suspect the administration of steroids. The purpose of the present study was to set up, assess and compare two complementary mass spectrometry-based metabolomic strategies as new tools to screen for steroid abuse in cattle and demonstrate the feasibility of such approaches. The protocols were developed in two European laboratories in charge of residues analysis in the field of food safety. Apart from sample preparation, the global process was different in both laboratories from LC-HRMS fingerprinting to multivariate data analysis through data processing and involved both LC-Orbitrap-XCMS and UPLC-ToF-MS-MetAlign strategies. The reproducibility of both sample preparation and MS measurements were assessed in order to guarantee that any differences in the acquired fingerprints were not caused by analytical variability but reflect metabolome modifications upon steroids administration. The protocols were then applied to urine samples collected on a large group of animals consisting of 12 control calves and 12 calves administrated with a mixture of 17β-estradiol 3-benzoate and 17β-nandrolone laureate esters according to a protocol reflecting likely illegal practices. The modifications in urine profiles as indicators of steroid administration have been evaluated in this context and proved the suitability of the approach for discriminating anabolic treated animals from control ones. Such an approach may therefore open a new way for the screening of anabolic steroid administration through targeted monitoring of relevant biomarkers highlighted as a result of the metabolomics study.     

Metabolomic approach based on liquid chromatography coupled to high resolution mass spectrometry to screen for the illegal use of estradiol and progesterone in cattle

Administration of hormonal compounds as growth promoters in livestock farming was banned by Council Directive 93/22/EC, however, this kind of substances are sometimes reported within the framework of European monitoring residue plans. Various analytical methods have been previously developed to screen for their misuse, and they are now especially efficient for monitoring the illegal administration of synthetic and semi-synthetic hormones. Nevertheless, proving an exogenous administration of hormones from natural origin (i.e. estradiol-17β or progesterone) still remains a challenging task for European authorities. As a result of their origin, these target compounds are indeed always present in the analytical matrix, and because the concentration levels of natural steroids are extremely variable from one animal to another, the establishment of reference thresholds appears very difficult. During this preliminary study, metabolomic data was acquired on a high performance liquid chromatography system coupled to high resolution mass spectrometer (HPLC-LTQ-Orbitrap). Serum samples were collected from dairy cows treated or not with sex steroid hormones commonly employed in animal husbandry: estradiol-17β (or its ester estradiol benzoate) and progesterone. After appropriate data processing and multivariate statistical analyses (OPLS-DA), it was possible to highlight significant metabolic modifications in serum consecutively to the administration of estradiol and/or progesterone. Those differences were used to build predictive models able to suspect illegal administration of these hormones in cattle. Potential biomarker candidates of estradiol and/or progesterone were pointed out, that remains to be structurally elucidated.     

Thermal optimization of 1.55 μm OP-VECSEL with hybrid metal–metamorphic mirror for single-mode high power operation

We report on the thermal design and the characterization of InP-based 1.55 μm wavelength large diameter (～100 μm) optically pumped vertical external cavity surface emitting lasers (OP-VECSELs). The device is thermally optimized for high power ( > 70 mW) room-temperature (RT) continuous-wave (CW) single-mode operation. Efficient bottom heat dissipation in the 1/2-VCSEL chip is obtained thanks to the use of a hybrid metal– metamorphic GaAs/AlAs mirror integrated to the InP-based active region, and to subsequent soldering on a SiC substrate. A single-mode output power of 77mW is obtained under CW-RT laser operation, limited by the pump power. Moreover thermal simulations and characterizations of the 1/2-VCSEL chip show that even higher power could be obtained at higher pumping levels, using a CVD diamond substrate.     

Parameterization of Invariant Manifolds for Periodic Orbits (II): A Posteriori Analysis and Computer Assisted Error Bounds

In this paper we develop mathematically rigorous computer assisted techniques for studying high order Fourier–Taylor parameterizations of local stable/unstable manifolds for hyperbolic periodic orbits of analytic vector fields. We exploit the numerical methods developed in Castelli et al. (SIAM J Appl Dyn Syst 14(1):132–167, 2015) in order to obtain a high order Fourier–Taylor series expansion of the parameterization. The main result of the present work is an a-posteriori theorem which provides mathematically rigorous error bounds. The hypotheses of the theorem are checked with computer assistance. The argument relies on a sequence of preliminary computer assisted proofs where we validate the numerical approximation of the periodic orbit, its stable/unstable normal bundles, and the jets of the manifold to some desired order M. We illustrate our method by implementing validated computations for two dimensional manifolds in the Lorenz equations in \(\mathbb {R}^3\) and a three dimensional manifold of a suspension bridge equation in \(\mathbb {R}^4\).