Layer‐by‐Layer All‐Inorganic Quantum‐Dot‐Based LEDs: A Simple Procedure with Robust Performance

A novel all‐inorganic electroluminescent device is demonstrated based on highly luminescent CdTe nanocrystals intercalated within a laminar hydrotalcite‐like structure. The laminar scaffold acts to both support and distribute the CdTe nanocrystals. The device is synthesized using simple wet chemical processes at room temperature in ambient conditions. It has high thermal stability, operating continuously up to 90 °C, and a maximum efficiency at J = 0.12 A cm^?2. The device is targeted at the automotive industry.     

Unfreezable Water in Apple Treated by Pulsed Electric Fields: Impact of Osmotic Impregnation in Glycerol Solutions

The effects of pulsed electric fields (PEF) and osmotic impregnation in glycerol solution on the amount of unfreezable water in apple were determined by means of low-temperature differential scanning calorimetry (DSC). The obtained data were compared with behaviour of pure water–glycerol solutions (sample WG). PEF treatment was applied using a near-rectangular monopolar generator with pulse duration of 100 μs at electric field strength of 800 V/cm. The osmotic impregnation of PEF-treated apple discs was done using water–glycerol (sample AWG) and apple juice–glycerol (sample AJG) osmotic solutions at different concentration of water or juice in glycerol, W = 30–100 wt%. The data evidenced that for the PEF-treated samples the glycerol was able to penetrate successfully inside apple tissue. The state diagrams for WG, AWG and AJG samples were rather similar. It was observed that free water existed only for moisture content above some minimum value. The unfreezable water content was the largest in AJG, followed by WG and AWG. The juice concentration in glycerol W ≈ 80 wt% was found to be optimal for preservation of the texture of PEF-treated samples.     

The characterization of non-planar graphene nanowires with an Ω shape cross-section

We report on SEM, AFM, and Raman identification of non-planar several monolayer-thick graphene nanostructures with curved shapes. During mechanical exfoliation we obtained graphene flakes with nanowire/nanotube-like objects (diameters between 8 and 35 nm) with cross-sectional profile reminiscent of the Greek capital letter omega (Ω). The curved shapes of these objects were confirmed by AFM and SEM imaging. Non-planar Ω - nanostructures open up new possibilities for graphene electron energy band engineering.     

Gyrotron Output Power Stabilization by PID Feedback Control of Heater Current and Anode Voltage

To provide stable output power of a gyrotron during long operation time the power stabilization was achieved by two schemes with PID feedback control of heater current and anode voltage. It was based on the dependence of the output power on both the anode voltage and the beam current and also on the dependence of the beam current on the gun heater current. Both schemes provided decrease of the power standard deviation to 0.3-0.5%. The comparison between parameters of both schemes is discussed in the paper.     

Structuring and Mechanical Properties of Composite Ceramics SiC(C) ― Si3N4, Sintered under High Pressure

We have studied the kinetics of high-pressure sintering of a composite SiC(C) ― Si₃N₄ powder of a certain phase composition. We consider structuring and mechanical properties of the ceramics obtained on the basis of this powder.     

Stochastic model of reaction rate oscillations during CO oxidation over zeolite-supported catalysts

The particle size effect on the oscillatory behaviour during CO oxidation over zeolite-supported Pd catalysts is simulated with the help of a deterministic point model and a stochastic mesoscopic model. The point model is developed on the basis of Sales, Turner and Maple (STM) model, which is modified to consider the effects of the oxidation of the Pd bulk upon the catalyst activity. It is demonstrated that the deterministic point model can simulate the main properties of regular reaction rate oscillations. The stochastic model is based on the developed point model and simulates the reaction by a Markovian chain of elementary transitions, which correspond to changes in numbers of atoms and molecules of reagent species on the surface of Pd particle due to elementary steps of reaction. The stochastic model explains the role of statistical fluctuations and correlations in the reaction dynamics on the surface of an nm-sized catalyst particle.     

Orthodontic wire: a continuing evolution

Previous studies have shown that large doses of vitamin A potentiate chemical-induced liver injury and that the Kupffer cell is directly involved in this potentiation. Therefore, these studies were designed to determine if Kupffer cells isolated from vitamin A treated male Sprague-Dawley rats (75 mg/kg/day for 3-7 days as all- trans-retinol) had altered activity and function. Respiratory activity of Kupffer cells isolated from rats treated with vitamin A for 3 to 7 days markedly increased. Similarly, phagocytic activity was significantly elevated (up to 9-fold) after exposure to vitamin A for 3 to 7 days. Production of reactive oxygen species, measured by luminol-enhanced chemiluminescence of Kupffer cells isolated after 7 days of vitamin A exposure, was significantly higher than that of control cells when stimulated with opsonized zymosan. Also, the release of superoxide anion by individual Kupffer cells isolated from vitamin A treated rats was nearly three times greater than that of control cells. Basal production of tumor necrosis factor-alpha (TNF-alpha) and prostaglandin E2 (PGE2) production were significantly elevated in Kupffer cells isolated from rats treated with vitamin A. Lastly, peripheral blood monocytes (PBMC) isolated from rats treated with vitamin A for 7 days had a significantly greater respiratory activity, as well as TNF-alpha and PGE2 production, than PBMC isolated from control rats. Our data suggest that large doses of vitamin A enhance both Kupffer cell and PBMC function. Upregulation of the activity by these phagocytic cells may play a role in the vitamin A potentiation of chemical-induced liver injury.