Regulation of mouse and human mast cell development, survival and function by stem cell factor, the ligand for the c-kit receptor

Stem cell factor (SCF), the ligand for the receptor (SCFR) that is encoded by the c-kit proto-oncogene, has many important effects in mouse and human mast cell development, survival, and function. SCF can promote mast cell survival by suppressing apoptosis, induce mast cell hyperplasia in murine rodents, experimental primates and humans, directly induce SCFR-dependent mast cell mediator release, and significantly modulate the extent of mast cell activation by Fc epsilon RI-dependent mechanisms. These findings raise several clinical issues and, in some cases, point to potentially significant therapeutic opportunities.     

Thermal, dynamic mechanical and rheological properties of metallocene-catalyzed cycloolefin copolymers (mCOCs) with high glass transition temperature

We have successfully synthesized and pelletized metallocene-catalyzed cycloolefin copolymers (mCOCs). Furthermore, their thermal oxidation, dynamic mechanical and rheological properties have also been investigated by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and capillary rheometer, respectively. Their decomposition temperature (Td), glass transition temperature (Tg), and maximum damping (tanδ) are 450 °C, 203 °C and 2.6, respectively. The thermal oxidation for lab-made mCOC results from free-radical-induced reaction, causing discoloration, and its b* value (CIE LAB system) is 29.67. With 1,2-bis(3,5-di-tert-butyl-4-hydroxyhydro-cinnamoyl)hydrazine as an antioxidant, its b* value can effectively decrease and reach − 0.48. Experimental results reveal it is a tough and flexible polymer for a variety of applications since it possesses excellent thermal stability and mechanical properties.     

Submicron-size patterning on the sapphire substrate prepared by nanosphere lithography and nanoimprint lithography techniques

In this paper, we demonstrate and compare the formation of ordered etching masks for submicron-size patterned sapphire substrates through use of the nanosphere lithography and nanoimprint lithography methods. The metal honeycomb network structure and the polymer pillar protrusion structure were obtained from these two methods. Subsequently, the inductively-coupled-plasma reactive ion etching technique was applied to etch the sapphire substrates, and the etchant mixture gases of boron trichloride and argon with the flow rate ratio of 1 to 6 were introduced into the etchant chamber. Two types of submicron -pattern structures were obtained on the sapphire substrate surface after the etching processes were completed. One type of sapphire substrate was the submicron hole array structure and another type was the submicron cone array structure. The working pressure had a considerable effect on the shape geometry and etching rate, and the possible mechanism is discussed.     

Thermal error compensation method for machine center

High-speed machining (HSM) technology has become the most important application in metal cutting industries. However, overcome the positioning error is one of a great concern. The position error happens due to poor machine structure design and thermal expansion comes from cutting, especially when HSM is applied. In this paper, a new technique is developed to compensate for these errors. The thermal images are used to confirm dispersion of all the affect positions. PT-100 thermo-measuring sensors are applied to detect the thermal expansion. And a mathematical model is built by multi-variable regression analysis, which is based on the sensed temperature variation and the thermal expansion. Finally, these errors are reduced significantly by sending a feedback to the microprocessor. Meanwhile, the thermal deformation can be compensated by the mathematical model, under the condition when the machine is equipped with linear encoder. Moreover, based on the simulation, it is possible to reduce the number of sensors from ten to six, which save the memory capacity and great benefit for calculating and speeding the process of algorithm. The model improves the accuracy of machining which meets the precision requirement of HSM technology. As the result of various machining tests, the axial positioning error can be reduced from 20 μm to be 3 μm, which is a significantly improvement than existing methods.     

浓香型白酒生产区土壤微生物群落结构的季节性变化

采用高通量测序技术对浓香型白酒生产车间外的土壤微生物季节性变化趋势及主要影响因子进行分析,并与酿酒相关微生物进行比对。结果表明,土壤微生物群落结构和多样性有显著的季节性变化,冬季土壤微生物总数量显著高于夏季,季节对细菌的影响大于真菌。细菌优势菌群不同季节相对丰度占比无显著性差异（P＞0.05）,真菌优势菌群子囊菌门（Ascomycota）呈极显著性差异（P＜0.01）。通过冗余分析（RDA）,pH和有机碳分别是影响细菌和真菌群落结构变化的主要环境因子,解释率分别为12.7%、7.6%。此外,土壤中发现有酿酒微生物的存在,细菌共有11个菌属,真菌共有18个菌属,瘤胃球菌属（Ruminococcus）和芽孢杆菌属（Bacillus）是优势细菌菌群,镰刀菌属（Fusarium）、曲霉属（Aspergillus）、枝孢菌属（Cladosporium）则是优势真菌菌群。     

Effects of temperature on columnar microstructure and recrystallization of TiO2 film produced by ion-assisted deposition

Titanium oxide thin films were deposited by electron-beam evaporation with ion-beam-assisted deposition. The effect of the substrate temperature and annealing temperature on the columnar microstructure and recrystallization of titanium oxide was studied. The values of the refractive index varied from 2.26 to 2.4, indicating that the different substrate temperatures affected the film density. X-ray diffraction revealed that all films were amorphous as deposited. At annealing temperatures from 100 degrees C to 300 degrees C, only the anatase phase was formed. As the substrate temperature increased from 150 degrees C to 200 degrees C to 250 degrees C, the recrystallization temperature fell from 300 degrees C through 250 degrees C to 200 degrees C. Changing the substrate temperature resulted in the formation of various types of columnar microstructure, as determined by scanning-electron microscopy. Different columnar structures resulted in different surface morphologies, as measured by atomic-force microscopy.     

城市流动摊贩治理困境与优化策略研究

流动摊贩与城市发展之间的矛盾一直是城市治理中的难点。本文以合肥三里庵商圈内疏导区及周边流动摊贩区为研究对象,明确疏导区的设置使得流动摊贩管控有所改善,但忽视了非正规经济的特质与优势,仍存在诸多问题。通过分析城市治理与摊贩特质之间的矛盾根源,反思当前困境。尝试从政府部门、城市规划者、物业公司及摊贩自身提出多维度共同监管策略,以期为满足流动摊贩的需求提供有效帮助及为城市治理提供合理借鉴。