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Chirality plays a significant role in the physical properties and biological functions of many biological materials, e.g., climbing tendrils and twisted leaves, which exhibit chiral growth. However, the mechanisms underlying the chiral growth of biological materials remain unclear. In this paper, we investigate how the Towel Gourd tendrils achieve their chiral growth. Our experiments reveal that the tendrils have a hierarchy of chirality, which transfers from the lower levels to the higher. The change in the helical angle of cellulose fibrils at the subcellular level induces an intrinsic torsion of tendrils, leading to the formation of the helical morphology of tendril filaments. A chirality transfer model is presented to elucidate the chiral growth of tendrils. This present study may help understand various chiral phenomena observed in biological materials. It also suggests that chirality transfer can be utilized in the development of hierarchically chiral materials having unique properties. Many biological materials, such as climbing plant tendrils 1,2 , flower petals of Paphiopedilum dianthum 3 , and snail shells 4 , exhibit chiral growth. In these natural materials, there are a number of distributed chiral elements, e.g., biomacromolecules, which lead to the formation of various chiral morphologies and surface patterns at the macroscopic scale. For example, helices and twisted belts are often observed to form in growing biological materials. These chiral morphologies generally tend to a specific handedness, either right or left 5 . A well-known example is climbing tendrils, which help some climbing plants attach to trees or other objects and to provide supporting forces 2 . The investigation of the mechanisms underlying the chiral growth of biological materials is a fundamental and important issue in not only developmental biology but also materials science and technology.The chiral shapes of some biological and artificial materials may origin from the asymmetry of growth, deswelling 6,7 , surface stresses 8,9 and other physical quantities associated with anisotropic atomic or molecular structures 10 . For example, the formation of twisting belts of Bauhinia seed pods 6 and chiral polymer lamellae 3 has been attributed to the anisotropy of material properties and surface stresses, respectively. From the view point of chirality transfer, the chiral morphologies of many biological materials originate from the chirality of their microscopic constituent building blocks. Typical examples include the flagellar filaments of bacteria [11][12][13] , the flower petals of Paphiopedilumdilum dianthum 3 , and the stork's bill awns 14,15 . Their chiral growth is caused by the helical arrangements of protein lattices, cortical microtubules, and tilted celluloses at the micro scale, respectively. The helical tendrils of climbing plants have attracted the interest of many scientists since the pioneering work of Charles Darwin 2 . A recent study suggested that Cucumber tendril coiling might be induced by the asymmetric contra...

Many materials have been theoretically predicted to be half-metallic, and hence suitable for use as pure spin sources in spintronic devices. Yet to date, remarkably few of these predictions have been experimentally verified. We have used spin polarized photoelectron spectroscopy to study one candidate half-metallic system, Fe(3)O(4). Such experiments are normally hampered by difficulties in producing clean stoichiometric surfaces with a polarization that is truly representative of that of the bulk. However, by utilizing higher photon energies than have traditionally been used for such experiments, we can study polarization in 'as received' samples, essentially 'looking through' the disrupted surface. High quality, strain relieved, ex situ prepared Fe(3)O(4) films have been thoroughly characterized by diffraction, transport and magnetometry studies of their crystallographic, electronic and magnetic properties. The spectroscopic results are found to agree fairly closely with previously published experimental data on in situ grown thin films and cleaved single crystals. However, despite the higher photoelectron kinetic energies of the experiment, it has not been possible to observe 100% polarization at the Fermi level. Hence, our data do not support the claim of true half-metallicity for Fe(3)O(4).

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