Many industrially important materials, ranging from ceramics to catalysts to pharmaceuticals, are polycrystalline and cannot be grown as single crystals. This means that non-conventional methods of structure analysis must be applied to obtain the structural information that is fundamental to the understanding of the properties of these materials. Electron microscopy might appear to be a natural approach, but only relatively simple structures have been solved by this route. Powder diffraction is another obvious option, but the overlap of reflections with similar diffraction angles causes an ambiguity in the relative intensities of those reflections. Various ways of overcoming or circumventing this problem have been developed, and several of these involve incorporating chemical information into the structure determination process. For complex zeolite structures, the FOCUS algorithm has proved to be effective. Because it operates in both real and reciprocal space, phase information obtained from high-resolution transmission electron microscopy images can be incorporated directly into this algorithm in a simple way. Here we show that by doing so, the complexity limit can be extended much further. The power of this approach has been demonstrated with the solution of the structure of the zeolite TNU-9 (|H9.3|[Al9.3Si182.7O384]; ref. 10) with 24 topologically distinct (Si,Al) atoms and 52 such O atoms. For comparison, ITQ-22 (ref. 11), the most complex zeolite known to date, has 16 topologically distinct (Si,Ge) atoms.

A general approach for preparing enzyme-polymer nanoconjugates that respond to temperature in organic media is presented. These nanoconjugates readily dissolve in organic solvents for homogenous catalysis at 40 °C and showed greatly enhanced apparent catalytic activities. The recovery of the soluble enzyme-polymer nanoconjugates is accomplished by temperature-induced precipitation.

The conversion process of an Aurivillius phase, Bi(2)W(2)O(9), into a layered tungstic acid by hydrochloric acid treatment has been investigated, and resultant H(2)W(2)O(7) x nH(2)O has been fully characterized. The c parameter of Bi(2)W(2)O(9) [2.37063(5) nm] decreases to 2.21(1) nm in an acid-treated product dried at ambient temperature. The a and b parameters of Bi(2)W(2)O(9) [a = 0.54377(1) nm and b = 0.54166(1) nm] also decrease slightly to a = 0.524(1) nm and b = 0.513(1) nm in the acid-treated product dried at ambient temperature, indicating structural changes in the ReO(3)-like slabs in Bi(2)W(2)O(9) upon acid treatment. Drying at 120 degrees C leads to a further decrease in the c parameter [1.86(1) nm] with no notable change in the a and b parameters [a = 0.5249(2) nm and b = 0.513(2) nm]. The formation of an expandable layered structure is demonstrated by the successful intercalation of n-octylamine [interlayer distance 2.597(9) nm] and n-dodecylamine [interlayer distance 3.56(2) nm]. The compositions of the acid-treated products are determined to be H(2)W(2)O(7) x nH(2)O typically with n = 0.58 for the air-dried product and n = 0 for the product dried at 120 degrees C. As a consequence, the composition of the layer is H(2)W(2)O(7), and the decrease in the c parameter upon drying is ascribable to the loss of interlayer water. Scanning electron microscopy reveals no morphological change during acid treatment, which strongly suggests a selective leaching of the bismuth oxide sheets as a reaction mechanism. High-resolution transmission electron microscopy (HREM) observation of the acid-treated product shows consistency with a structural model for H(2)W(2)O(7), derived from Bi(2)W(2)O(9) through removal of the bismuth oxide sheets and contraction along the c axis. HREM observation also reveals that the WO(6) octahedra arrangement changes slightly with acid treatment. A one-dimensional electron density map projected on the c axis for the product dried at 120 degrees C, H(2)W(2)O(7), shows good consistency with that calculated for the structural model.

Dedicated to Professor Chunli Bai, President of the Chinese Academy of Sciences, in celebration of his 60th birthday.With the rapid development of nanoscience and nanotechnology, [1a] nanostructured biocatalysts that take the advantage of nanomaterials in terms of both functional and structural availability have offered new opportunities for improving biological functions of enzymes and expanding applications in areas such as biosensors, bioanalytical devices, and industrial biocatalysis. [1] Recently, we reported a method of preparing protein-inorganic hybrid nanostructures with flower-like shapes, [2] which have shown much greater activities than free enzymes and most of the reported immobilized enzymes. [3] To bring this appealing catalyst into practical use, however, an effective accommodation of these high-performance enzyme catalysts is required. One way is to weakly attach these enzyme nanoflowers to porous materials by physical adsorption. Recently, Krieg et al. [4] reported the fabrication of a supramolecular membrane by noncovalent modification of a commercial membrane, which suggests the possibility of fabricating functional filtration membranes by a simple post-modification procedure, thus enabling many new and interesting applications. It thus came to our mind to fabricate a membrane incorporating enzyme nanoflowers for the rapid detection of hazardous compounds through visualization of the catalyzed product. Owing to their high toxicity even at a low concentration, [5] phenols are listed as major toxic pollutants by the Environmental Protection Agency of the USA and other countries. [6] Sensitive detection of phenolic compounds has been well established using instrumental analysis such as liquid chromatography. [7] However, these methods usually require sophisticated instrumentation and a multistep procedure, making them less convenient for rapid and on-site detection.The present study started by the fabrication of an enzyme nanoflower incorporated into a membrane. As shown in Figure 1, a suspension of laccase-inorganic hybrid nanoflowers, which have a high activity (ca. 200 % that of free laccase) for phenol oxidization, as we observed previously, [2] was injected into a commercial disposable syringe filter equipped with a cellulose acetate membrane (pore size 0.2 mm). This procedure thus deposited enzyme nanoflowers with an average size of 4 mm onto the membrane. Then the aqueous sample containing phenol was mixed with an aqueous solution of 4-aminoantipyrine and was passed through the membrane with incorporated laccase nanoflowers, causing oxidative coupling of phenol with 4-aminoantipyrine to form an antipyrine dye [8] that has an absorption maximum at 495 nm. This procedure allowed rapid analysis by a UV/ Vis spectrophotometer or by the naked eye. Finally, pure water was injected into the filter to remove unreacted reagents and the reaction products, followed by drying the membrane in air for the next use.For the preparation of laccase-copper phosphate nanoflowers, typically, 0.8 mm aqueous Cu...

As a new textile fiber produced from Neosinocalamus affinis, the structures of the bamboo fiber were studied thoroughly in this research. Using Fourier-transform infrared (FTIR) (using a Micro-FTIR Spectrometer), X-ray diffraction (XRD), nuclear magnetic resonance (NMR) spectroscopy and scanning electron microscopy (SEM), we investigate the chemical composition, crystalline structure, molecular and morphology structure, respectively. Results show that the chemical composition of bamboo fiber is the same as all bast fibers, that is, cellulose constitutes the majority and lignin needs to be reduced further for textile applications. The bamboo fiber belongs to cellulose I crystalline structure as flax, cotton and ramie, while has a small molecular mass and a low degree of polymerization. The cross section of the single bamboo fiber is round with small lumen. It can be predicted that bamboo fiber has high breaking strength, but low elongation and has good water absorption properties. The structural characteristics of the bamboo fiber are different from those of other textile plant fibers.

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Graphene macroscopic materials have attracted tremendous attention for their fascinating performance and rich functionalities. Here, we provide an elaborate description of techniques in the fabrication of graphene macroscopic materials, focusing on the wet-spinning of 1D fibers and wet-spinning of continuous 2D films and 3D ultraflyweight aerogels. The thread of the research concepts is discussed to offer an overview of graphene macroscopic assembly. We summarize the fabrication system of wet-spinning of fiber and films, which extends to the chemistry of solvated graphene, the formation of graphene LCs, and the chemical/thermal reduction of graphene materials. The experimental details of graphene ultraflyweight aerogel are also been described. We hope that this paper can act as an experimental guidance for researchers, and become suggestive for forthcoming advances in graphene macroscopic materials.

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