Photoredox catalysis for polymerization reactions

Photoredox catalysis is now well-known in organic synthesis for the formation of free radicals under very soft irradiations conditions (e.g. sunlight, household fluorescence or LED bulbs, Xe lamp). This method has been introduced here to the polymer chemistry area to initiate ring opening polymerizations (ROP) or free radical polymerizations (FRP). The present paper will give an up-to date situation of the photocatalyst achievements in FRP and ROP.     

Analytical formulation for the deformations of I-shapes and RHS at the plastic strain ultimate limit state

The development of “full plastic hinges” in the most stressed cross-sections is a common hypothesis considered in the elastic-plastic design of steel structures. The equations for the internal forces at the plastic limit state are then based on equilibrium conditions only, and they do not allow the global deformations corresponding to each combination of internal forces at this ultimate limit state to be estimated.This paper presents a simplified analytical model for the elastic-plastic analysis of rectangular hollow sections and bisymmetrical I-sections bent about their strong axis. This model states the relations between the global deformations (axial deformation and bending curvature) and the corresponding internal forces (axial force and bending moment) at the cross-section plastic strain ultimate limit state. It allows a realistic evaluation of the cross-section ductility, based on a relevant strain limitation at the most strained cross-section fibres.     

Characterization of ultrathin SOI film and application to short channel MOSFETs

In this study, a very dilute solution (NH(4)OH:H(2)O(2):H(2)O 1:8:64 mixture) was employed to reduce the thickness of commercially available SOI wafers down to 3?nm. The etch rate is precisely controlled at 0.11???s(-1) based on the self-limited etching speed of the solution. The thickness uniformity of the thin film, evaluated by spectroscopic ellipsometry and by high-resolution x-ray reflectivity, remains constant through the thinning process. Moreover, the film roughness, analyzed by atomic force microscopy, slightly improves during the thinning process. The residual stress in the thin film is much smaller than that obtained by sacrificial oxidation. Mobility, measured by means of a bridge-type Hall bar on 15?nm film, is not significantly reduced compared to the value of bulk silicon. Finally, the thinned SOI wafers were used to fabricate Schottky-barrier metal-oxide-semiconductor field-effect transistors with a gate length down to 30?nm, featuring state-of-the-art current drive performance.     

Predictive wavefront control for adaptive optics with arbitrary control loop delays

We present a modification of the closed-loop state space model for adaptive optics control that allows delays that are a noninteger multiple of the system frame rate. We derive the new forms of the predictive Fourier control Kalman filters for arbitrary delays and show that they are linear combinations of the whole-frame delay terms. This structure of the controller is independent of the delay. System stability margins and residual error variance both transition gracefully between integer-frame delays.     

SAPHIR: a physiome core model of body fluid homeostasis and blood pressure regulation

We present the current state of the development of the SAPHIR project (a Systems Approach for PHysiological Integration of Renal, cardiac and respiratory function). The aim is to provide an open-source multi-resolution modelling environment that will permit, at a practical level, a plug-and-play construction of integrated systems models using lumped-parameter components at the organ/tissue level while also allowing focus on cellular- or molecular-level detailed sub-models embedded in the larger core model. Thus, an in silico exploration of gene-to-organ-to-organism scenarios will be possible, while keeping computation time manageable. As a first prototype implementation in this environment, we describe a core model of human physiology targeting the short- and long-term regulation of blood pressure, body fluids and homeostasis of the major solutes. In tandem with the development of the core models, the project involves database implementation and ontology development.     

Characterization of a yeast D-amino acid oxidase microbiosensor for D-serine detection in the central nervous system

d-Serine is an endogenous ligand for N-methyl-d-aspartate (NMDA) receptors, and alterations in its concentration have been related to several brain disorders, especially schizophrenia. It is therefore an important target neuromodulator for the pharmaceutical industry. To monitor d-serine levels in vivo, we have developed a microbiosensor based on cylindrical platinum microelectrodes, covered with a membrane of poly-m-phenylenediamine (PPD) and a layer of immobilized d-amino acid oxidase from the yeast Rhodotorula gracilis (RgDAAO). By detecting the hydrogen peroxide produced by enzymatic degradation of d-serine, this microbiosensor shows a detection limit of 16 nM and a mean response time of 2 s. Interferences by ascorbic acid, uric acid, l-cysteine, and by biogenic amines and their metabolites are rejected at more than 97% by the PPD layer. Although several d-amino acids are potential substrates for RgDAAO, d-serine was the only endogenous substrate present in sufficient concentration to be detected by our microbiosensor in the central nervous system. When implanted in the cortex of anesthetized rats, this microbiosensor detected the increase in concentration of d-serine resulting from its diffusion across the blood-brain barrier after an intraperitoneal injection. This new device will make it possible to investigate in vivo the variations in d-serine concentrations occurring under normal and pathological conditions and to assess the pharmacological potency of new drugs designed to impact d-serine metabolism.     

Electron propagation along Cu nanowires supported on a Cu(111) surface

We present a joint experimental-theoretical study of the one-dimensional band of excited electronic states with sp character localized on Cu nanowires supported on a Cu(111) surface. Energy dispersion and lifetime of these states have been obtained, allowing the determination of the mean distance traveled by an excited electron along the nanowire before it escapes into the substrate. We show that a Cu nanowire supported on a Cu(111) surface can guide a one-dimensional electron flux over a short distance and thus can be considered as a possible component for nanoelectronics devices.     

Nanomosaic network for the detection of proteins without direct electrical contact

A nanomosaic network of metallic nanoparticles for the detection of ultralow concentrations of proteins is reported, which uses two planar microelectrodes embedded in a microchip that permit generation of capacitive coupling to the nanomosaic system without the need for direct electrical contact with the channel. By tailoring the microchannel surface using a sandwich configuration of polyethylene terephthalate/gold nanoparticles/poly(L-lysine), the surface charge can be modified following biomolecular interactions and monitored using a noncontact admittance technique. This nanodevice system behaves like a tunable capacitor and can be employed for the detection of any kind of molecule. The femtomolar detection of an anionic protein, such as beta-lactoglobulin in phosphate-buffered saline medium, is taken as an example.     

Redirecting NK cells mediated tumor cell lysis by a new recombinant bifunctional protein

Natural killer (NK) cells are at the crossroad between innate and adaptive immunity and play a major role in cancer immunosurveillance. NK cell stimulation depends on a balance between inhibitory and activating receptors, such as the stimulatory lectin-like receptor NKG2D. To redirect NK cells against tumor cells, we designed bifunctional proteins able to specifically bind tumor cells and to induce their lysis by NK cells, after NKG2D engagement. To this aim, we used the 'knob into hole' heterodimerization strategy, in which 'knob' and 'hole' variants were generated by directed mutagenesis within the CH3 domain of human IgG1 Fc fragments fused to an anti-CEA or anti-HER2 scFv or to the H60 murine ligand of NKG2D, respectively. We demonstrated the capacity of the bifunctional proteins produced to specifically coat tumor cells surface with H60 ligand. Most importantly, we demonstrated that these bifunctional proteins were able to induce an NKG2D-dependent and antibody-specific tumor cell lysis by murine NK cells. Overall, the results show the possibility to redirect NK cytotoxicity to tumor cells by a new format of recombinant bispecific antibody, opening the way of potential NK cell-based cancer immunotherapies by specific activation of the NKG2D receptor at the tumor site.     

A micro-method for the estimation of oil content and fatty acid composition in seeds with special reference to cyclopropenoic acids

A micro-method is described for the routine estimation of oil content and fatty acid composition in seeds containing cyclopropenoic fatty acids (CPEFA) by determination of the total and component long-chain fatty acids. The oil was transmethylated without prior extraction using 1.17% sodium methoxide in methanol at 80°C for 45 min. The resultant fatty acid methyl esters were separated and measured by gas-liquid chromatography using a glass capillary column coated with Carbowax 20 M at 170°C. The method was shown to be applicable to a wide range of seeds including cottonseed (Gossypium hirsutum), kapok (Ceiba pentandra), paka (Urena lobata), baobab (Adansonia grandidieri and A. suarezensis). Individual seeds can be used with this method which needs only 50 to 150 mg for analysis. Results obtained with this micro-method were reproducible and good recoveries of oil and individual fatty acids were observed. The micro-method was compared for the determination of CPEFA (malvalic plus sterculic acids) to the nuclear magnetic resonance quantitation and gas-liquid chromography after derivatisation of CPEFA in more stable compounds.