Density functional theory calculation of refractive indices of liquid-forming silicon oil compounds

A combination of quantum chemical calculation and molecular dynamics simulation is applied to compute refractive indices of liquid-forming silicon oils. The densities of these species are obtained from molecular dynamics simulations based on the NPT ensemble while the molecular polarizabilities are evaluated by density functional theory. This procedure is shown to yield results well compatible with available experimental data, suggesting that it represents a robust and economic route for determining the refractive indices of liquid-forming organic complexes containing silicon.     

Colorimetric detection of manganese(II) ions using alginate-stabilized silver nanoparticles

Research on Chemical Intermediates - Marine algal polysaccharides have been recognized as the most effective and promising substrates for reduction and stabilization of metal nanoparticles....     

Growth control of stoichiometry in LaMnO3 epitaxial thin films by pulsed laser deposition

We have studied structural, magnetic, and optical transport properties of LaMnO₃ (LMO) thin films grown on SrTiO₃. While the stoichiometric LMO is an insulating antiferromagnet, it tends to be a ferromagnetic insulator when grown as thin films. By exploring the majority of growth parameters, we have found that the bulk-like electronic and magnetic phases can be stabilized by growing thin films under reducing atmospheres and by using more energetic laser processes. These conditions are found to reduce the La deficiency in the film resulting in the greatly improved cation stoichiometry. Since oxides are prone to reduce the oxygen content and to alter the cation ratio under such growth conditions, it suggests that the cation and oxygen stoichiometries in complex oxide thin films can be improved by properly optimizing the growth parameters.     

Graphene-induced apoptosis in lung epithelial cells through EGFR

Expanding interest in nanotechnology applied to electronic and biomedical fields has led to fast-growing development of various nanomaterials. Graphene is a single-atom thick, two-dimensional sheet of hexagonally arranged carbon atoms with unique physical and chemical properties. Recently, graphene has been used in many studies on electronics, photonics, composite materials, energy generation and storage, sensors, and biomedicine. However, the current health risk assessment for graphene has been relatively limited and inconclusive. This study evaluated the toxicity effects of graphene on the airway epithelial cell line BEAS-2B, which represents the first barrier of the human body to interact with airborne graphene particles. Our result showed that graphene can induce the cellular Ca²⁺ by phospholipase C (PLC) associated pathway by activating epidermal growth factor receptor (EGFR). Subsequently, inositol 1,4,5-triphosphate (IP₃) receptors activate the release of Ca²⁺ from the endoplasmic reticulum (ER) Ca²⁺ stores. Those Ca²⁺ signals further trigger the calcium-regulated apoptosis in the cell. Furthermore, the stimulation can cause EGFR upregulation, which have been demonstrated to associate with diseases such as lung cancer, chronic obstructive pulmonary disease (COPD), and cardiovascular diseases. This study highlights the additional health risk considering that it can function as a contributing factor for other respiratory diseases.     

Dynamic output-feedback guaranteed cost control for linear systems with uniform input quantization

There have existed the researches on guaranteed cost control for systems with the dynamic or logarithmic quantizer; however, intensive studies not only on continuous-time output-feedback linear systems with uniform input quantization but also on guaranteed cost control for such systems have not been carried out thus far. This paper first solves the problem of guaranteeing the linear quadratic (LQ) cost for continuous-time output-feedback linear systems with uniform input quantization. The proposed output-feedback controller comprises the main and the additional control parts. The former part is designed as a linear dynamic output-feedback controller for determining the fundamental characteristics of the system associated with the LQ cost, and the latter part is constructed as an integer multiple of the quantization level for eliminating the effect of uniform input quantization. The additional control part adopts the state estimate instead of the state itself, which causes the state estimation errors. By computing their quantity added to the upper bound of the LQ cost, this paper shows that the proposed controller still guarantees the LQ cost despite the state estimation errors.     

Biodegradable thermosensitive micelles of PEG-PLGA-PEG triblock copolymers

Micellization of poly(ethylene glycol-b-(DL-lactic acid-co-glycolic acid)-b-ethylene glycol), PEG-PLGA-PEG, triblock copolymers in water was studied by ¹³C-NMR (nuclear magnetic resonance), dye solubilization method, and light scattering. Critical micelle concentration was decreased by half by increasing temperature from 20 to 50°C. Enthalpy of micellization was calculated to be 10–20 KJ/mole. Apparent aggregation number, diameter of a micelle abruptly increased while second viral coefficient decreased at ≈30°C suggesting that micellar growth as well as an increase in polymer–polymer attraction occur at this temperature. These findings might suggest that the sol to gel transition at high concentration of aqueous solutions of this polymer is driven by conformational changes of micelles.