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Drought is the greatest agro-meteorological disaster. Risk assessment of drought is of great guiding significance to improve the regional risk management and decision-making level, and to further reduce agricultural loss. In this paper, drought risk of summer maize was analyzed accor-ding to natural disaster risk theory, using the data of weather, planting area and yield of summer maize, and local effective irrigation area of 69 stations in Huanghuaihai area. The assessing indices and models of drought risk were established from the aspects of danger, vulnerability, exposure, and disaster prevention and mitigation capacity. The results showed that, in Huanghuaihai area, the most dangerous periods for drought during summer maize season (June-September) were the follo-wing two stages: sowing to emergence and milky to maturity. Spatially, the highest drought risk was mainly distributed in central and southern Hebei, western and northern Henan. After weighting the vulnerability, exposure, and disaster prevention and mitigation capacity, the integrated highest drought risk was mainly distributed in the west and southwest of Henan Province. The sub-high risk area was distributed in the south of Henan, Cangzhou and Xingtai of Hebei, and Dezhou of Shandong. The lowest risk area was located in south of Shandong, north of Anhui, and Xinyang of Henan. The other areas were at moderate risk.

We report a simple method of creating well-defined micropatterns on the surface of a flat PDMS stamp, making it suitable for microcontact printing of proteins. This method only requires a UV lamp (254 nm) and a TEM grid (as a photomask) to modify the surface of PDMS for creating desired micropatterns. By using the UV-modified stamp, a printed protein micropattern that resembles the original TEM grid can be obtained. Surprisingly, unlike the oxygen-plasma-treated PDMS, the UV-modified flat stamp is also long-lasting (>1 week). The method reported herein is very economical for microcontact printing applications because expensive silicon masters and microstructured PDMS are no longer required.

Protein assays are critical analytical tools performed in various biochemical laboratories to quantify the concentration of proteins. In this study, we report the optical responses of a thin layer of liquid crystals supported on glass slides decorated with proteins and the utility of this phenomenon as a new "all-or-nothing" type of protein assay. It was found that the orientations of liquid crystals are very sensitive to the concentration of protein solution applied to the surface. When the protein concentration exceeds a critical value (IgG 5.0 microg/mL, BSA 6.0 microg/mL, FTIC-anti-biotin 0.40 microg/mL, and FITC-anti-IgG 0.37 microg/mL), the thin layer of liquid crystals gives a very sharp dark-to-bright optical response within a small concentration range. This characteristic is not observed in any traditional protein assays, which are based on the adsorption of UV or visible light. The optical response is also very precise and reproducible. It is not affected by the thickness of the liquid crystal cell or the amount of organosilanes coated on the glass slides. The liquid crystal-based protein assay may be very useful for screening purposes, especially when a simple positive or negative answer is desired.