[Preliminary study on premixed materials of emulsion gel].

The purpose of this paper was to study the pre-mixed materials of emulsion gel. Accessories were screened and formula was designed with the most common use, low cost and simple process as the standards. Experiments were designed by central composite design-response surface methodology (ccd-rsm). 8.0.6 Trial Design-Expert was used for data processing and analysis, and subjective scores were used as the index to draw the three-dimensional effect surface and 2D contour maps. It was determined that the optimal ranges were A (carbomer 940)： 0.05-0.065 g; B (castor oil)： 1.00-1.12 mL; C (poly polysorbate-80)： 0.15 mL. The optimal formula was as follows： carbopol 0.057 5 g, castor oil 1.1 mL, polysorbate-80 0.15 mL. The formulated substrate was studied on its preliminary stability and rheology characteristics, such as viscosity and thixotropy. Then with the optimal formula as substrate, emulsion type gel was prepared respectively with 98% rutin, 98% berberine hydrochloride, and 98% berbamine hydrochloride as the main component. With 0.9% normal saline as the absorption solution, the results showed that the ransdermal flux of the three formulations of 1 h was all less than 1%. The results indicated that this substrate had the potential to be developed into a premixed material. The emulsion type gel matrix made from this formula had a good appearance, stability to certain extent, appropriate viscosity and thixotropy, and showed no skin irritation in 1 h.

Monolithically integrated stretchable photonics.

Mechanically stretchable photonics provides a new geometric degree of freedom for photonic system design and foresees applications ranging from artificial skins to soft wearable electronics. Here we describe the design and experimental realization of the first single-mode stretchable photonic devices. These devices, made of chalcogenide glass and epoxy polymer materials, are monolithically integrated on elastomer substrates. To impart mechanical stretching capability to devices built using these intrinsically brittle materials, our design strategy involves local substrate stiffening to minimize shape deformation of critical photonic components, and interconnecting optical waveguides assuming a meandering Euler spiral geometry to mitigate radiative optical loss. Devices fabricated following such design can sustain 41% nominal tensile strain and 3000 stretching cycles without measurable degradation in optical performance. In addition, we present a rigorous analytical model to quantitatively predict stress-optical coupling behavior in waveguide devices of arbitrary geometry without using a single fitting parameter.

Transfer of metals from soil to vegetables in an area near a smelter in Nanning, China.

A field survey was conducted to investigate the metal contamination in soils and vegetables, and to evaluate the possible health risks to local population through foodchain transfer near a smelter in Nanning, southern China. Contamination levels in soils and vegetables with cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) were measured, and transfer factors (TF) from soils to vegetable plants and its health risk (risk index, RI) were calculated accordingly. Results showed that both soils and vegetables from villages 1 and 2 (V1 and V2, 1500 m and 500 m from the smelter) were heavily contaminated, compared to a village 50 km from the smelter. Geometric mean of Cd and Pb concentrations in vegetables for V1 and V2, respectively, were 0.15 and 0.24 mg Cd kg(-1) and 0.45 and 0.38 mg Pb kg(-1) (on fresh weight basis). Oral intake of Cd and Pb through vegetables poses high health risk to local residents. Risk indices for V1 and V2, respectively, were 3.87 and 7.42 for Cd, and 1.44 and 13.5 for Pb. The complexity of metal contamination and their health risks are also discussed.

Selecting iodine-enriched vegetables and the residual effect of iodate application to soil.

A greenhouse pot experiment was conducted to select vegetables for iodine uptake. The residual effect of iodate fertilization on the growth of and iodine uptake by spinach plants were also investigated. Six vegetables, including leafy vegetables (pakchoi [Brassica chinensis L.], spinach [Spinacia oleracea L.]), tuber vegetables (onion [Allium cepa L.]), shoot vegetables (water spinach [Ipomoea aquatica Forsk.], celery [Apium graveolens L.]), and root vegetables (carrot [Daucus carota var. sativa DC.]) were examined. Results showed that the concentrations of iodate in soil had significant effect on the biomass of edible parts of pakchoi and spinach (p<0.01), whereas the concentrations of iodate in soil had no significant effect on that of carrots, water spinach, celery, and onion. Iodine concentrations in edible parts of vegetables and the transfer factors (TFedible parts) of soil-to-edible parts of vegetables significantly increased with increasing iodine concentrations in soil (p<0.001), and iodine concentrations in edible parts and TFedible parts of spinach were much higher than those of other vegetables at any treatment. Both transfer coefficients for edible parts (TCedible parts) and for aerial parts (TCaerial parts) of vegetables changed differently with increasing iodine concentrations in the soil, and TCedible parts and TCaerial parts of spinach were higher than those of other vegetables. Therefore, spinach was considered as an efficient vegetable for iodine biofortification. Further experiment showed that there is considerable residual effect of soil fertilization with iodate.

Anisotropic surface strain in single crystalline cobalt nanowires and its impact on the diameter-dependent Young's modulus.

Understanding and measuring the size-dependent surface strain of nanowires are essential to their applications in various emerging devices. Here, we report on the diameter-dependent surface strain and Young's modulus of single-crystalline Co nanowires investigated by in situ X-ray diffraction measurements. Diameter-dependent initial longitudinal elongation of the nanowires is observed and ascribed to the anisotropic surface stress due to the Poisson effect, which serves as the basis for mechanical measurements. As the nanowire diameter decreases, a transition from the "smaller is softer" regime to the "smaller is tougher" regime is observed in the Young's modulus of the nanowires, which is attributed to the competition between the elongation softening and the surface stiffening effects. Our work demonstrates a new nondestructive method capable of measuring the initial surface strain and estimating the Young's modulus of single crystalline nanowires, and provides new insights on the size effect.

Rapid fabrication of nanoneedle arrays by ion sputtering.

We report a novel method for rapidly fabricating ordered nanoneedles using an ion beam that cuts through the Fe/GaAs single thin layer or the Fe/MgO/Fe/GaAs multilayer producing a pillar pattern followed by raster-scanning normal to the patterned area. However, such ordered nanoneedles were not formed on the pure GaAs substrate surface without the thin Fe film coating, nor were nanoneedles formed on the GaAs substrate coated with a thin Cr epitaxial film, when this method was used. It has advantages over other methods, being simple, fast and well controlled for fabricating one-dimensional nanostructure arrays, leading to a range of applications such as high aspect ratio sharp tips for atomic force microscope/atom probes and consequent possible quantum confinement effects or arrays of nanostructures for field-optical/photoluminescence emission and data recording.