[Study on polysaccharide content and monosaccharide composition of Polyporus umbellatus from different production areas].

In order to provide scientific basics for exploitation and sufficient application of Polyporus umbellatus resources and study the monosaccharide composition of P. umbellatus polysaccharides,the anthrone-sulfuric acid method was applied to compare polysaccharide content of P. umbellatus from 17 producing areas. The monosaccharides were derived by 1-phenyl-3-methyl-5-pyrazolone( PMP) and the derivatives were identified by UPLC-MS/MS and the content of each monosaccharide component was determined simultaneously. The results demonstrated that there was a certain difference in total polysaccharide content of P. umbellatus from different regions,and the content of total P. umbellatus polysaccharide from Shaanxi province and Sichuan province( 1. 15% and 1. 90%) was relatively higher than that of others areas. Polysaccharides from P. umbellatus was mainly composed of eight monosaccharides,including glucose,glucuronic acid,galactose,ribose,xylose,arabinose,mannose and fucose. The contents of glucose( 17. 65 mg·g-1) was higher than others. The ribose was the lowest( 0. 13 mg·g-1). In addition,fructose,rhamnose and galacturonic acid were also detected in some samples. Furthermore,the results of cluster analysis( CA) and principal component analysis( PCA) indicated that totally 17 batches of P. umbellatus polysaccharide could be classified into three clusters,samples collected from Wuchang in Heilongjiang province were clustered into one group separately. The study can provide a basis for rational utilization of P. umbellatus resources,and also implies the sequence of monosaccharide linking and pharmacological activity of P. umbellatus polysaccharides.

[Analysis of monosaccharide composition of twelve polysaccharides by pre-column derivatization procedure UPLC-MS/MS].

This study is to establish a pre-column derivatization procedure with 1-phenyl-3-methyl-5-pyrazolone (PMP) UPLC-MS/MS method for the determination of the monosaccharide composition of 12 polysaccharides. At the same time, the monosaccharide components of polysaccharides in Armillaria gallica were analyzed. The separation was performed on a ACQUITY ZORBAX RRHD Eclipse Plus C18 column(2.1 mm×100 mm, 1.8 µm),using 95% acetonitrile (A) and ammonium acetate-5% acetonitrile-water (B) as mobile phase with gradient elution. The target components were detected in multiple-reaction monitoring (MRM) mode by mass spectrometry with electrospray ionization (ESI) source operated in ionization mode. The results showed that based on the monosaccharides detection method established by UPLC-MS/MS, the linearity of the 12 monosaccharides components were linear in their linear range (R²>0.990), and the recovery rate were 92.30%-105.6%. 11 monosaccharides such as fructose, mannose, and glucose were detected in A. gallica samples. The method established in this experiment is robust, highly reproducible and accurate, and is suitable for the determination of monosaccharide components such as A. gallica.

Mesocrystals--ordered nanoparticle superstructures.

Mesocrystals are 3D ordered nanoparticle superstructures, often with internal porosity, which receive much recent research interest. While more and more mesocrystal systems are found in biomineralization or synthesized, their potential as material still needs to be explored. It needs to be revealed, which new chemical and physical properties arise from the mesocrystal structure, or how they change by the ordered aggregation of nanoparticles to fully exploit the promising potential of mesocrystals. Also, the mechanisms for mesocrystal synthesis need to be explored to adapt it to a wide class of materials. The last three years have seen remarkable progress, which is summarized here. Also potential future directions of this reaserch field are discussed. This shows the importance of mesocrystals not only for the field of materials research and allows the appliction of mesocrystals in advanced materials synthesis or property improvement of existing materials. It also outlines attractive research directions in this field.

Polyelectrolyte-directed nanoparticle aggregation: systematic morphogenesis of calcium carbonate by nonclassical crystallization.

Besides the classical atom/ion/molecule based mechanism, nonclassical crystallization provides a nanoparticle-based crystallization pathway toward single crystals. However, there is a lack of experimentally established strategies for engineering a range of crystalline microstructures from common nanoparticles by nonclassical crystallization. We demonstrate that a commercial random copolymer polyelectrolyte poly(4-styrene sulfonate)-co-(maleic acid) (PSS-co-MA) considerably guides crystallization of calcium carbonate (CC) with a high versatility. The bioinspired nonclassical crystallization protocol yielded a series of calcite microstructures. Calcite single crystals obtained at low supersaturation show a pseudo-dodecahedral shape with curved faces, whereas increasing supersaturation generated calcite mesocrystals with pseudo-octahedral shapes and scalloped surfaces. Further increase of supersaturation induced the formation of polycrystalline multilayered and hollow spheres. In the initial growth stage of all these microstructures, amorphous CC nanoparticles formed as the early product. Remarkably, microparticles with minimal primitive (P)-surface were captured as the prominent intermediate indicative of liquidlike behavior. Moreover, nanogranular structures exist broadly in the as-synthesized crystals. These results demonstrate that the polyelectrolyte can effectively stabilize the amorphous CC nanoparticle precursors, impart control over the evolution from amorphous precursors via a liquid aggregate through P-surface intermediates to the final crystals, and thus allow the morphogenesis. Simple variation of calcium and polyeletrolyte concentrations enables a systematic control over the size and morphology of particles among pseudo-dodecahedra, pseudo-octahedra, multilayered spheres, and hollow spheres, which are expressed in a morphology diagram. A unifying nanoparticle aggregation formation mechanism was suggested to explain the morphogenesis by the combination of nonclassical crystallization and surface area minimization principles.

Synthesis of copper-core/carbon-sheath nanocables by a surfactant-assisted hydrothermal reduction/carbonization process.

A simple hydrothermal method has been developed for the one-step synthesis of copper-core/carbon-sheath nanocables in solution. The obtained nanostructures were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM), Raman, and UV-vis spectrum analysis. These copper@carbon nanocables formed through the hydrothermal reduction/carbonization in the presence of surfactant cetyltrimethylammonium bromide (CTAB) acting as the structure-directing agent by hydrothermal treatment. HRTEM and selected-area electron diffraction (SAED) indicate that the resulted Cu nanowires had the preferred [110] growth direction. The influence of the reaction temperature, reaction time, and pH on the final products was investigated in detail. The possible formation mechanism for copper-core/carbon-sheath nanocables was also proposed. Amorphous carbon nanotubes can be obtained by etching the copper core in the nanocables.

Novel multilamellar mesostructured molybdenum oxide nanofibers and nanobelts: synthesis and characterization.

One-dimensional molybdenum oxide nanostructures with layered mesostructures were prepared directly from commercial bulk MoO3 crystals by a surfactant-templated hydrothermal process. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, infrared spectra, and thermal analyses have been used to characterize the obtained molybdenum oxide nanomaterials. By use of cetyltrimethylammonium bromide as the structure-directing template, novel molybdenum oxide nanofibers with triple interlayer distances of 2.84, 2.66, and 2.46 nm have been obtained. The nanofibers have diameters of 20-100 nm and length up to 20 microm. The growth of multilamellar molybdenum oxide nanofibers can be interpreted by the combination of surfactant/inorganic self-assembly process and host/guest intercalation chemistry. On the basis of the X-ray diffraction and infrared results, a possible arrangement of surfactant in the interlayer space of molybdenum oxide by bilayer micelles with different tilt angles has been proposed. In addition, the thermal stability of surfactant has been improved by intercalation. Moreover, molybdenum oxide nanobelts with two kinds of interlayered structures were also produced in the presence of n-alkylamines (n = 12, 14, 16, and 18) following a similar method, these nanobelts show length up to more than 10 microm, width ranging between 200 and 600 microm, and width-to-thickness ratios of about 3-12. A linear relationship is observed between the interlayer distance and the number of carbon atoms in n-alkyl chains.

Systematic synthesis and characterization of single-crystal lanthanide orthophosphate nanowires.

A simple hydrothermal method has been developed for the systematic synthesis of lanthanide orthophosphate crystals with different crystalline phases and morphologies. It has been shown that pure LnPO(4) compounds change structure with decreasing Ln ionic radius: i.e., the orthophosphates from Ho to Lu as well as Y exist only in the tetragonal zircon (xenotime) structure, while the orthophosphates from La to Dy exist in the hexagonal structure under hydrothermal treatment. The obtained hexagonal structured lanthanide orthophosphate LnPO(4) (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy) products have a wirelike morphology. In contrast, tetragonal LnPO(4) (Ln = Ho, Er, Tm, Yb, Lu, Y) samples prepared under the same experimental conditions consist of nanoparticles. The obtained hexagonal LnPO(4) (Ln = La --> Tb) can convert to the monoclinic monazite structured products, and their morphologies remained the same after calcination at 900 degrees C in air (Hexagonal DyPO(4) is an exceptional case, it transformed to tetragonal DyPO(4) by calcination), while the tetragonal structure for (Ho--> Lu, Y)PO(4) remains unchanged by calcination. The resulting LnPO(4) (Ln = La --> Dy) products consist almost entirely of nanowires/nanorods with diameters of 5-120 nm and lengths ranging from several hundreds of nanometers to several micrometers. Europium doped LaPO(4) nanowires were also prepared, and their photoluminescent properties were reported. The optical absorption spectrum of CePO(4) nanowires was measured and showed some differences from that of bulk CePO(4) materials. The possible growth mechanism of lanthanide phosphate nanowires was explored in detail. X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, electron diffraction, infrared absorption spectra, X-ray photoelectron spectroscopy, optical absorption spectra, and photoluminescence spectra have been employed to characterize these materials.