一种面向动态连续查询的查询索引

针对当前面向连续查询的查询索引不适应查询动态变化的问题,提出一种能承受频繁更新的动态连续查询索引。为实现该索引,设计一种基于网格和树的索引结构,该索引结构继承了网格结构的高效更新性能的优点,并通过继承树的特性,克服网格结构高空间开销的问题。实验结果表明,该连续查询索引比基于网格的连续查询索引节省空间开销约一个数量级;比基于树的连续查询索引更新效率提高约70%,查询性能提高约25%。

Comparative Analysis of Five Different Homologous Feeder Cell Lines in the Ability to Support Rhesus Embryonic Stem Cells

In our previous study, five homologous feeder cell lines, Monkey ear skin fibroblasts （MESFs）, clonally derived fibroblasts from the MESFs （CMESFs）, monkey oviductal fibroblasts （MOFs）, monkey follicular granulosa fibroblast-like （MFGs） cells, monkey follicular granulosa epithelium-like （MFGEs） cells, were developed for the maintenance of rhesus embryonic stem cells （rESCs）. We found that MESFs, CMESFs, MOFs and MFGs, but not MFGEs, support the growth of rhesus embryonic stem cells. Moreover, we detected some genes that are upregulated in supportive feeder cell lines by semi-quantitative PCR. In the present study, we applied the GeneChip Rhesus Macaque Genome Array of Affymetrix Corporation to study the expression profiles of these five feeder cell lines, in purpose to find out which cytokines and signaling pathways were important in maintaining the rESCs, mRNAs of eight genes, including GREM2, bFGF, KITLG, DKK3, GREM1, AREG, SERPINF1 and LTBP1, were found to be upregulated in supportive feeder cell lines, but not in MFGE. The results indicate that many signaling pathways may play redundant roles in supporting the undifferentiated growth and maintenance of pluripotency in rESCs.

Fault-Tolerant Control of Nonlinear Systems Based on Fuzzy Neural Networks

Due to its great potentisl value in theory and application, fault-tolerant control atrategies of nonlinear systems, especially combining with intelligent control methods, have been a focus in the academe. A fault-tolerant control method based on fuzzy neural networks was presented for nonlinear systems in this paper. The fault parameters were designed to detect the fault, adaptive updating method was introduced to estimate and track fault, and fuzzy neural networks were used to adjust the fault parameters and construct automated fault diagnosis. And the fault compeusation control force, which was given by fault estimation, was used to realize adaptive fault-tolerant control. This framework leaded to a simple structure, an accurate detection, and a high robusmess. The simulation results in induction motor show that it is still able to work well with high dynamic performance and control precision under the condition of motor parameters＇ variation fault and load torque disturbance.

CD133^+ gallbladder carcinoma cells exhibit self-renewal ability and tumorigenicity

AIM： To identify cancer stern cells （CSCs） in human gallbladder carcinomas （GBCs）. METHODS： Primary GBC cells were cultured under serum-free conditions to produce floating spheres. The stem-cell properties of the sphere-forming cells, including self-renewal, differentiation potential, chemoresistance and tumorigenicity, were determined in vitro or in vivo. Cell surface expression of CD133 was investigated in primary tumors and in spheroid cells using flow cytometry. The sphere-colony-formation ability and tumorigenicity of CD133＋ cells were assayed.floating spheroids were generated from primary GBC cells, and these sphere-forming cells could generate new progeny spheroids in serum-free media. Spheroid cells were differentiated under serum-containing conditions with downregulation of the stem cell markers Oct-4, Nanog, and nestin （P 〈 0.05）. The differentiated cells showed lower spheroid-colony-formation ability than the original spheroid cells （P 〈 0.05）. Spheroid ceils were more resistant to chemotherapeutic reagents than the congenetic adherent cells （P 〈 0.05）. Flow cytometry showed enriched CD133＋ population in sphereforming cells （P 〈 0.05）. CD133＋ cells possessed high colony-formation ability than the CD133 population （P 〈 0.01）. CD133＋ cells injected into nude mice revealed higher tumorigenicity than their antigen-negative counterparts （P 〈 0.05）. CONCLUSION： CD133 may be a cell surface marker for CSCs in GBC.

Self-renewal Capacity of Several Species of the Genus Sternbergia Possessing Medicinal Properties

The present work dealt with sexual reproduction capacity of three relic species of the genus Sternbergia （family AmaryUidaceae） distributed in the Caucasus, i.e., Sternbergia lutea （L.） Ker Gawl. ex Spreng., Sternbergiafischeriana （Herb.） Roem and Sternbergia colchiciflora Waldst. ＆ Kit.. Under this study, the natural populations of species, which possess valuable medicinal and ornamental properties, have been assessed by experts as vulnerable, and S. colchiciflora is included in the red list of endemic plants of the Caucasus, as having status of the critically endangered species. The situation is aggravated by the poor self-regeneration capacity of these species, which is one of the main factors responsible for the sustainability of the population of this or that species in the wild. Self-regeneration capacity for sexual reproduction was investigated in the listed species of the genus Sternbergia using common methods of embryology and reproduction biology. In conditions of the National Botanical Garden of Georgia （NBGG）, the species S. lutea and S. fischeriana prove to be completely infertile and propagate vegetatively by bulblets, while S. colchiciflora revealed the ability for propagation by seed. Long-term conservation of seeds of the studied species S. colchiciflora in the Caucasus Regional Seed Bank （CRSB） and establishing of living collections of this species at the experimental plot were chosen as the method for safeguarding this critically endangered species.