Effects of different mulching modes on soil nitrate concentration and grain yield of Linum usitatissimum in dry land.

To investigate soil NO3--N dynamics and yield increasing effect of mulching planting for Linum usitatissimum (oil flax) in semi-arid Loess Plateau, we examined the effects of three mul-ching modes (whole field plastic mulching and micro ridges with soil cover and bunch-seeding; whole field plastic mulching with soil cover and bunch-seeding; and straw mulching with strips) on seed yield and distribution of soil NO3--N during the main growth periods of oil flax, with the conventional planting model as control (CK) in 2015 and 2016. Results showed that the average yield under mulching modes was increased by 56.1% (2015) and 22.7% (2016). The treatment of whole field plastic mulching with soil cover and bunch-seeding had the highest grain yield. Mulching treatments significantly increased soil water content. Soil water content was increased first and then reduced in the whole growth stage of oil flax. The soil NO3--N content was gradually decreased during the oil flax growth process. In both years, NO3--N content in 0-40 cm soil depth under mul-ching treatments were increased by 3.1%-18.6% (2015) and 5.1%-16.4% (2016) at budding stage of oil flax, respectively. The whole field plastic mulching with soil cover and bunch-seeding treatment showed the larges increases across all treatments. In 2015, NO3--N accumulation in 0-100 cm soil depth between the flowering and maturity stages of oil flax were increased by 10.2%-22.2% and 8.6%-21.4%, respectively. Especially during the more rainfall period of maturity stage, NO3--N accumulation in 0-40 cm soil depth was significantly enhanced by 3.3%-4.9% than that in 40-100 cm soil depth. It indicated that more rainfall could slow down the migration of NO3--N to the lower layer under the mulching modes in the maturity stage. In 2016, high temperature and drought at late growth stages had a great influence on oil flax growth. The NO3--N accumulation in 0-100 cm soil depth at the maturity stage was increased by 6.6%-18.0%. There was significant correlation between NO3--N content and grain yield during the main growth stages of oil flax. In conclusion, the whole field plastic mulching with soil cover and bunch-seeding treatment was the most appropriate way of oil flax production in arid and semi-arid area.

[Multilineage potential of pulp stem cells from human young permanent teeth in vitro].

OBJECTIVE: To isolate and culture the pulp cells from human young permanent teeth (pDPC), and to observe their biological characteristics and the expression of some specific markers, and to induce these pulp cells to differentiate into osteoblast, adipocyte, neuron and chondrocyte lineages. METHODS: Pulp cells were isolated and cultured from orthodontic extracted premolars of children. The attached cells after at least 3 passages were used for the following experiments: 1. Morphology and ultrastructure analysis; 2. Cell cycle and phenotype were analyzed by flowcytometry; 3. Growth curve were recorded; 4. pDPC were induced to differentiate into osteoblast, adipocyte, neuron in vitro, and were identified by histochemical methods and RT-PCR. RESULTS: 1. Attached pDPCs were fibroblast-like cells, which were distinguished from BMSC. 2. The cell organs in dDPCs were well developed. 3. pDPCs were highly positive for CD90, CD44, CD147, which are mesenchymal stem-cell markers, but were negative for other markers including CD34, CD38, CD45, HLA-DR. 4. pDPCs showed high growth rate. 5. pDPCs could be induced to differentiate into osteoblast, adipocyte, and neuron lineages, but not chondrocyte lineages. CONCLUSION: pDPCs were characterized by their ability to proliferate with high growth rate in vitro. The expression of some BMSC markers in these cells were observed. They showed the potential to differentiate into multiple mesenchymal lineages such as osteoblast, adipocyte, neuron lineages under specific conditions in vitro.

Asymmetrical polar modification of a bivanadium-capped Keggin POM by multiple Cu-N coordination polymeric chains.

An unprecedented asymmetrically modified bivanadium-capped Keggin polyoxometalate (POM), {AsMo12O40(VO)[VO(H2O)]}.[Cu(4,4'-bipy)]5.H2O (1) (bipy = bipyridine), has been hydrothermally synthesized and structurally characterized by a routine technique. Single-crystal X-ray diffraction analysis reveals that compound 1 exhibits a unique (3,4,6)-connected 3D framework with a (6(2).8(1))2(8(3))2(6(4).8(2))2(6(1).8(14)) topology, constructed from {AsMo12O40(VO)[VO(H2O)]}5- polyoxoanions modified by six {Cu(bipy)}n coordination polymeric chains. The asymmetrical polar coordination mode has never been found in the POM chemistry hitherto. It is also the first example of the bivanadium-capped POM as an anionic template to construct a 3D framework with the highest connection number of bicapped POMs. Additionally, by just changing the length of the organic ligand, a new compound {[AsMo12O40(VO)2][Cu(bpe)]2}.[Cu(bpe)].[H2bpe].H2O (2) (bpe = bis(4-pyridyl)ethylene), has been obtained, in which the {AsMo12O40(VO)2} sections are modified by double monotrack {Cu(bpe)}n coordination polymeric chains to form a "rail-like" 1D structure.