Au-Ag alloy nanoparticles supported on mesoporous aluminosilicate have been prepared by one-pot synthesis using hexadecyltrimethylammonium bromide (CTAB) both as a stabilizing agent for nanoparticles and as a template for the formation of mesoporous structure. The formation of Au-Ag alloy nanoparticles was confirmed by X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, and transmission electron microscopy (TEM). Although the Au-Ag alloy nanoparticles have a larger particle size than the monometallic gold particles, they exhibited exceptionally high activity in catalysis for low-temperature CO oxidation. Even at a low temperature of 250 K, the reaction rate can reach 8.7 x 10(-6) mol.g(cat.)(-1).s(-1) at an Au/Ag molar ratio of 3/1. While neither monometallic Au@MCM-41 nor Ag@MCM-41 shows activity at this temperature, the Au-Ag alloy system shows a strongly synergistic effect in high catalytic activity. In this alloy system, the size effect is no longer a critical factor, whereas Ag is believed to play a key role in the activation of oxygen.

In biomineralization, organisms can exert great control over mineral deposition from the solution phase by using biomolecules as matrices or molds.[1] One of the most surprising elements is the formation of single crystals with hierarchical structures and occluded biomolecules. [2] In some cases, such as the spines of sea urchins, the whole skeleton is one giant, single crystal with structured interior voids.[3] The normal concept of forming a pure and perfect inorganic, single crystal by molecular or ionic attachment is challenged. Calcium carbonate (CaCO 3 ) exhibits rather rich polymorphs including calcite, aragonite, vaterite, and amorphous calcium carbonate in biominerals. [4] In the laboratory, the morphogenesis of CaCO 3 using biopolymers or organic molecules as templates leads to various polymorphs and forms of CaCO 3 .[5±10] Faceted, porous single crystals of CaCO 3 with occluded biomolecules, have, however, not previously been synthesized in the laboratory. Here, we show that hexagonal particles of CaCO 3 (vaterite, a metastable polymorph) with intracrystalline gelatin were obtained from the hydrothermal reaction between calcium nitrate and urea in the presence of gelatin. The overall morphology of these particles obeys the single-crystal nature of vaterite, though they are formed first from nanocrystal aggregations. Although the use of various molecules for the template synthesis of vaterite has previously been reported, [5,10±12] here we demonstrate the growth process of vaterite crystals originating from vaterite nanocrystals. Gelatin is a denatured protein with a high molecular weight. The gelatin used in our experiments was derived from lime-cured bovine skin. It has been reported that cross-linked gelatin containing high-concentrations of polypeptides (poly-L-aspartate and poly-L-glutamate) can induce the crystallization of CaCO 3 .[13] In our experiments, Ca(NO 3 ) 2 , urea, and gelatin were mixed together in a sufficient amount of water to form an homogeneous solution. At 100 C, the decomposition of urea led to the slow crystallization of CaCO 3 . The process of CaCO 3 precipitation was monitored by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and IR analysis. From the XRD pattern, the as-obtained products were identified as pure vaterite phase (hexagonal, a = 7.1473 , c = 16.917 , JCPDS 33-0268), a thermodynamically metastable phase of CaCO 3 . The coherent lengths calculated from the peak widths using the Sherrer equation on (004) (2h = 18.03), (110) (21.38), and (112) (23.24) were 127 nm, 113 nm, and 104 nm, respectively. This is reaching the resolution limit of the powder-XRD instrument we used. Thus, in size, the coherent domains are greater than, or equal to, 100 nm. The pure phase of vaterite was also confirmed by its IR spectrum. The IR absorption peaks at 877 cm ±1 and 746 cm ±1 are characteristic of vaterite. [14] In the absence of gelatin, only calcite was obtained. Gelatin seems to play an important role in ...

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DNA tests in normal subjects and patients with ataxia and Parkinson's disease (PD) were carried out to assess the frequency of spinocerebellar ataxia (SCA) and to document the distribution of SCA mutations underlying ethnic Chinese in Taiwan. MJD/SCA3 (46%) was the most common autosomal dominant SCA in the Taiwanese cohort, followed by SCA6 (18%) and SCA1 (3%). No expansions of SCA types 2, 10, 12, or dentatorubropallidoluysian atrophy (DRPLA) were detected. The clinical phenotypes of these affected SCA patients were very heterogeneous. All of them showed clinical symptoms of cerebellar ataxia, with or without other associated features. The frequencies of large normal alleles are closely associated with the prevalence of SCA1, SCA2, MJD/SCA3, SCA6, and DRPLA among Taiwanese, Japanese, and Caucasians. Interestingly, abnormal expansions of SCA8 and SCA17 genes were detected in patients with PD. The clinical presentation for these patients is typical of idiopathic PD with the following characteristics: late onset of disease, resting tremor in the limbs, rigidity, bradykinesia, and a good response to levodopa. This study appears to be the first report describing the PD phenotype in association with an expanded allele in the TATA-binding protein gene and suggests that SCA8 may also be a cause of typical PD.