Explanatory System of Support Vector Regression and Its Application in QSPR of Surfactants

In order to solve the problem of poor interpretability of support vector re- gression （SVR） applied in quantitative structure-property relationship （QSPR）, a com- plete set of explanatory system for SVR was established based on F-test, The nov- el explanatory system includes significance tests of model and single-descriptor im- portance, single-descriptor effect and sensitivity analysis, and significance tests of interaction between two descriptors, etc. The results of example indicated that the explanatory results of the new system were consistent well with those of stepwise linear regression model and quadratic polynomial stepwise regression model. The explanatory SVR model will play an important role in regression analysis such as QSPR.

Identification of key genes responsible for cytokine-induced erythroid and myeloid differentiation and switching of hematopoietic stem cells by RAGE

We utilized a unique culture system to analyze the expression patterns of gene, protein, and cell surface antigen, and the biological process of the related genes in erythroid and myeloid differentiation and switching of hematopoietic stem cells （HSCs） in response to cytokine alterations. Gene-specific fragments （266） identified from five populations of cytokine-stimulated HSCs were categorized into three groups： （1） expressed specifically in a single cell population; （2） expressed in two cell populations, and （3） expressed in three or more populations. Of 145 defined cDNAs, three （2%） were novel genes. Protein two-dimensional gel electrophoresis and flow cytometry analyses showed overlapped and distinguished protein expression profiles in the cell populations studied. Biological process mapping of mRNAs expressed in erythroid and myeloid lineages indicated that mRNAs shared by both lineages attended ＇core processes,＇ whereas genes specifically expressed in either lineage alone were related to specific processes or cellular maturation. Data from this study support the hypothesis that committed HSCs （El4 or G14） cells can still be redirected to develop into myeloid or erythroid cells when erythropoietin （EPO） is replaced with granulocyte-colony stimulating factor （G-CSF） under erythroid-cultured condition or G-CSF with EPO in myeloid-cultured environment, respectively. Our results suggest that genes or proteins co-expressed in erythroid and myeloid lineages may be essential for the lineage maintenance and switching in hematopoiesis.

Copper-mediated synthesis of PdI_2 colloidal spheres

A novel copper-mediated solvothermal method was proposed for synthesizing colloidal spheres of a new composition, palladium iodide （PdI2）. Typical procedure was designed to involve the introduction of cupric chloride （CuCI2） as weak oxidant. CuCI2 was found to be essential for preventing the easy formation of palladium deposits as well as facilitating the synthesis and assembly. Under the co-effect of CuC12 and the surfactant of polyvinylpyrrolidone （PVP）, neutral PdI2 colloidal spheres with narrow size distribution were successfully produced. Such ion-assisted synthetic method is believed to be prospective in producing well-constructed nanostructures.