2670 wileyonlinelibrary.com water droplet; [ 6 ] trichomes on the leaf surface are arranged with orientation to direct water droplets toward one end of the leaf to conserve water; [ 7 ] the wing surface of brown lacewing (Micromus tasmaniae) with microtrichia at different length-scale allow the insect to get through the wetted surfaces. [ 8 ] The above-mentioned surface all contain microscale geometry with special arrangement or topographies to infl uence the surface property. Specifi cally, leaf surface contains various trichomes that for some incline at an acute angle to guide water [ 7 ] while others retain water on leaves to improved photosynthetic environment. [ 9 ] Inspired by the peculiar trichome structures, this study attempted to adopt cone-shaped structures to systematically understand how the inclination of the trichome infl uences the wettability of leaves.Different strategies have been reported to obtain artifi cial microcone structures for the study of wetting property, including replica moulding, [ 2b , 10 ] laser irradiation, [11][12][13] reactive ion etching (RIE), [ 14,15 ] and chemical deposition. [ 16 ] However, the above methods are complicated or not fl exible enough to make microcones with tunable feature for our specifi c purpose. Previously, ferrofl uid-molding method, which made use of ferrofl uid as the master of the mother mold, has been demonstrated to fabricate microscale polymer arrays with controllable size. [ 17 ] In this study, we utilized the similar technique and further, modifi ed it for our particular purpose ( Figure 2 ). In the experiment, microcone structures with different inclination angle were generated by adjusting the direction of external magnetic fi eld applied to the ferrofl uid. Nickel thin fi lm was then deposited to give a nanoscale roughness layer. Wettability studies (contact angle, sliding angle) were analyzed, and the retention forces of droplet move against or along the orientation of cones were investigated. Results and DiscussionTo create cone-shaped structures resembling trichomes of plants, ferrofl uid-molding method was adopted. [ 17 ] As shown in Figure 3 a, the ferrofl uid was divided into microdroplets due to magnetic hydrodynamic instability and were arranged by the magnetic disks to form a hexagonal pattern. As the external Learning from nature, a series of cone-shaped structures resembling trichomes of plants are fabricated by ferrofl uid molding to understand the infl uence of geometry on wettability. Experimentally, ferrofl uid microdroplets are generated under an external magnetic fi eld, and their shape can be changed from right cones into oblique cones by tilting the external magnetic fi eld. Followed by hard molds made with UV-curable tri(propylene glycol) diacrylate, polydimethylsiloxane microcones with different inclination angle ( θ ) are subsequently generated. Nickel thin fi lm is deposited onto the microcones to form micro/nano dual-scale structures. The largest contact angle (CA) is obtained in nickel-deposited right cones (CA = 1...

Leaf variegation is often the focus of plant breeding. Here, we studied a variegated mutant of Phalaenopsis aphrodite subsp. formosana, which is usually used as a parent of horticultural breeding, to understand its anatomic and genetic regulatory mechanisms in variegation. Chloroplasts with well-organized thylakoids and starch grains were found only in the mesophyll cells of green sectors but not of yellow sectors, confirming that the variegation belongs to the chlorophyll type. The two-dimensional electrophoresis and LC/MS/MS also reveal differential expressions of PsbP and PsbO between the green and yellow leaf sectors. Full-length cDNA sequencing revealed that mutant transcripts were caused by intron retention. When conditioning on the total RNA expression, we found that the functional transcript of PsbO and mutant transcript of PsbP are higher expressed in the yellow sector than in the green sector, suggesting that the posttranscriptional regulation of PsbO and PsbP differentiates the performance between green and yellow sectors. Because PsbP plays an important role in the stability of thylakoid folding, we suggest that the negative regulation of PsbP may inhibit thylakoid development in the yellow sectors. This causes chlorophyll deficiency in the yellow sectors and results in leaf variegation. We also provide evidence of the link of virus CymMV and the formation of variegation according to the differential expression of CymMV between green and yellow sectors.

Using of a safe life approach is necessitated by the small critical crack sizes and rapid crack growth rates resulting from the severe vibratory environment of rotorcraft. However Based on the success of damage tolerance initiative for airframe structure, a crack growth based on damage tolerance approach is being examined for implementation into the design and management of dynamic components. In this paper the crack growth behavior in low cycle fatigue (LCF) and high cycle fatigue (HCF) are compared and the accuracy of several damage tolerance analysis methods in determining the crack growth life from an initial detectable crack size 1.25 mm to 12 mm for a rotorcraft main rotor yoke are investigated. The real rotorcraft materials measured by experiment and the fatigue load mean frequency spectrum based on statistical usage spectrum are adopted. The crack growth equations used in the programs are discussed to provide a basis for understanding the results. The results show that the load less than the safe fatigue limit has an important effect on crack growth life and it is reasonable for the material that the cut-off stress ratio for the threshold stress intensity factor range is set 0.7.

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