Hepatic and pancreatic effects of polyenoylphosphatidylcholine in rats with alloxan-induced diabetes

In neonatally allylestrenol treated animals in adult age a single benzpyrene treatment significantly decreases the female and significantly increases the male rat's sexual activity. Three month old females display the negative sexual behavioral effect of neonatal allylestrenol treatment less than the six month old ones. The benzpyrene treatment in adult age decreases the sexual activity of male rats. The experiments call the attention to the modifying effect of perinatal steroid treatments to similar exposure in adult age.     

A broad-band waveguide grating coupler with a subwavelength grating mirror

A new diffractive device for light coupling between a planar optical waveguide and free space is proposed. The device utilizes a second-order waveguide grating to diffract the fundamental waveguide mode into two free propagating beams and a subwavelength grating (SWG) mirror to combine the two free propagating beams into a single beam. The finite-difference time-domain (FDTD) simulations show that the SWG mirror improves the coupling efficiency of the waveguide fundamental mode into the single out-coupled beam from about 30% to 92%. A high efficiency (>90%) is predicted for a broad wavelength range of 1520-1580nm. The proposed device is compact (/spl sim/80 /spl mu/m in length) and it eliminates the need for blazing the waveguide grating.     

An energy–momentum consistent method for transient simulations with mixed finite elements developed in the framework of geometrically exact shells

In this paper, a mixed variational formulation for the development of energy–momentum consistent (EMC) time‐stepping schemes is proposed. The approach accommodates mixed finite elements based on a Hu–Washizu‐type variational formulation in terms of displacements, Green–Lagrangian strains, and conjugated stresses. The proposed discretization in time of the mixed variational formulation under consideration yields an EMC scheme in a natural way. The newly developed methodology is applied to a high‐performance mixed shell finite element. The previously observed robustness of the mixed finite element formulation in equilibrium iterations extends to the transient regime because of the EMC discretization in time. Copyright © 2016 John Wiley & Sons, Ltd.     

Structural,optical and electrical properties of silicon nanocrystals embedded in SixC1−x/SiC multilayer systems for photovoltaic applications

In this work we present a structural, optical and electrical characterization of Si_xC_1?x/SiC multilayer systems with different silicon content. After the deposition process, an annealing treatment was carried out in order to induce the silicon nanocrystals formation. By means of energy-filtered transmission electron microscopy (EFTEM) we observed the structural morphology of the multilayers and the presence of crystallized silicon nanoprecipitates for samples annealed up to 1100 °C. We discuss the suitability of optical techniques such as Raman scattering and reflectance and transmittance (R&T) for the evaluation of the crystalline fraction of our samples at different silicon excess ranges. In addition, the combination of R&T measurements with simulation has proved to be a useful instrument to confirm the structural properties observed by EFTEM. Finally, we explore the origin of the extremely high current density revealed by electrical measurements, probably due to the presence of an undesired defective SiC_yO_z ternary compound layer, already supported by the structural and optical results. Nevertheless, the variation of the electrical measurements with the silicon amount indicates a small but significant contribution from the multilayers.     

Identification and tackling of a parasitic surface compound in SiC and Si-rich carbide films

Silicon carbide and silicon rich carbide (SiC and SRC) thin films were prepared by PECVD and annealed at 1100 °C. Such a treatment, when applied to SiC/SRC multilayers, aimed at the formation of silicon nanocrystals, that have attracted considerable attention as tunable band-gap materials for photovoltaic applications. Optical and structural techniques (X-ray photoelectron spectroscopy, Reflectance and Transmittance, Fourier Transformed Infrared Spectroscopy) were used to evidence the formation, during the annealing treatment in nominally inert atmosphere, of a parasitic ternary SiO_xC_y surface compound, that consumed part of the originally deposited material and behaved as a preferential conductive path with respect to the nanocrystal layer in horizontal electrical conductivity measurements. The SiO_xC_y compound was HF-resistant, with composition dependent on the underlying matrix. It gave rise to a Si-O related vibration in FTIR analysis, that may be misinterpreted as due to silicon oxide. The compound, if neglected, can affect the structural and electrical characterization of the material.To overcome this problem, a procedure is analyzed, based on the deposition of a sacrificial capping a-Si:H layer that partially oxidizes, and is removed by tetra methyl ammonium hydroxide (TMAH) after annealing. XPS analysis revealed that the resulting surface is mainly made up of SiC regardless of the composition of the underlying SRC layer. Subsequent SF₆:O₂ dry etching results in a porous SiC-rich surface layer. The proposed method is effective in controlling the SRC surface configuration, and allows the performance of reliable optical and electrical characterization.     

Tetravinyl-tetramethylcyclo-tetrasiloxane (tetravinyl D4) is a mutagen in Rat2lambda lacI fibroblasts

We describe a patient with sporadic dystrophic epidermolysis bullosa associated with well-documented atopic dermatitis. We discuss this case in relation to a newly described clinical subtype of epidermolysis bullosa known as epidermolysis bullosa pruriginosa, a dystrophic variant associated with prominent pruritus. The relations of this case of sporadic dystrophic epidermolysis bullosa with other dominantly inherited forms of dystrophic epidermolysis bullosa such as the Pasini variant, the pretibial variant, and Bart's syndrome are also discussed. The role of atopic dermatitis in exacerbating dystrophic epidermolysis bullosa in this patient raises an important consideration in the care of this group of patients.     

A role for cAMP in long-term depression at hippocampal mossy fiber synapses

Mossy fiber synapses on hippocampal CA3 pyramidal cells, in addition to expressing an NMDA receptor-independent form of long-term potentiation (LTP), have recently been shown to express a novel presynaptic form of long-term depression (LTD). We have studied the mechanisms underlying mossy fiber LTD and present evidence that it is triggered, at least in part, by a metabotropic glutamate receptor-mediated decrease in adenylyl cyclase activity, which leads to a decrease in the activity of the cAMP-dependent protein kinase (PKA) and a reversal of the presynaptic processes responsible for mossy fiber LTP. The bidirectional control of synaptic strength at mossy fiber synapses by activity therefore appears to be due to modulation of the cAMP-PKA signaling pathway in mossy fiber boutons.