Design and Fabrication of Drug Delivery Devices with Complex Architectures Based on Three-dimensional Printing Technique

A new type of implantable drug delivery devices （ DDD ） with complicated architectures were fubricated by three-dimensional printing technique, employing levofloxacin （LVFX） as a model drug. Processing parameters were optimized in riew of the layer thickness, spucing between printed lines, flow rate of liquid binder and the fast axis speed. The prepared DDD prototype consists of a double-layer structure, of which the upper region is a reservoir system and the lower region is a matrix one. The in vitro release test revealed that LVFX was released in a dual-puse pattern. This DDD may present a new strategy for the prophylaxis and treatment of diseases such as bone infection in the near future.

Synthesis,Crystal Structure and Water Vapor Adsorption Property of a New Supramolecular Architecture

A new complex, [Cu（HL）（phen）（H2O）]·4H2O（1, H3L·HCl = 5-（（4-carboxypiperidin-1-yl）methyl）isophthalic acid hydrochloride, phen = 1,10-phenanthroline）, has been hydrothermally prepared and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and PXRD. Complex 1 crystallizes in monoclinic, space group P21/c with a = 14.5520（14）, b = 12.6659（12）, c = 15.5006（14） A, β = 97.224（2）o, V = 2834.3（5） A3, Z = 4, C27H33N3O11 Cu, Mr = 639.10, Dc = 1.498 g/cm3, μ = 0.837 mm-1, S = 1.047, F（000） = 1332, the final R = 0.0423 and w R = 0.1118 for 18772 observed reflections（I 〉 2σ（I））. The compound is a Cu（Ⅱ） centre mononuclear molecule in the asymmetric unit. The independent binuclear [Cu2（HL）2（phen）2] units are bridged to form a three-dimensional（3D） supramolecular polymer by extensive hydrogen bonds and π-π non-covalent bonding interactions. Moreover, thermogravimetric（TG） analysis and gas adsorption property of 1 were also discussed.

Natural variation of hormone levels in Arabidopsis roots and correlations with complex root architecture

Studies on natural variation are an important tool to unravel the genetic basis of quantitative traits in plants. Despite the significant roles of phytohormones in plant development, including root architecture, hardly any studies have been done to investigate natural variation in endogenous hormone levels in plants. Therefore, in the present study a range of hormones were quantified in root extracts of thirteen Arabidopsis thaliana accessions using a ultra performance liquid chromatography triple quadrupole mass spectrometer. Root system architecture of the set of accessions was quantified, using a new parameter （mature root unit） for complex root systems, and correlated with the phytohormone data. Significant variations in phytohormone levels among the accessions were detected, but were remarkably small, namely less than three-fold difference between extremes. For cytokinins, relatively larger variations were found for ribosides and glucosides, as compared to the free bases. For root phenotyping, length-related traits--lateral root length and total root length--showed larger variations than lateral root number-related ones. For root architecture, antagonistic interactions between hormones, for example, indole-3-acetic acid to trans-zeatin were detected in correlation analysis. These findings provide conclusive evidence for the presence of natural variation in phytohormone levels in Arabidopsis roots, suggesting that quantitative genetic analyses are feasible.