Hydrodynamics of particle clusters suspended in viscous fluids is a subject of considerable theoretical and practical importance. Using finite volume method, drag forces of interacting coaxial sphere chain suspended in Herschel-Bulkley fluid flow are investigated numerically. The contribution of this paper is to determine the drag force of interacting spheres. The effects of yield stress and separation distance on drag forces are explored systematically. The present results suggest that the creeping flow assumption is still valid for finite Reynolds number Re while the yield stress is large enough ( Od/ Re >10.0). For two spheres creeping flow, the interaction distance between each sphere is reduced with the increasing of the yield stress. For multi-spheres, the shielding and ending effects of the head and end spheres are significantly weakened due to the action of yield stress. [All rights reserved Elsevier]

A linearized instability analysis of Taylor–Couette flow between tworotating concentric cylinders of an electrorheological (ER) fluid iscarried out. The ER fluid exhibits a yield stress in addition to theplastic viscosity when an extra electric-field is applied. It can befound that the yield stress plays a dual role in the flow instability.The possibility of the yield surface falling between the cylinders isanalysed. Although small waves appeared on the yielded surface isconsidered, the yielded surface, which has been treated as a freesurface, has little effect on the flow instability. The effects ofaxisymmetric perturbation on the flow instability are presented due tothe axisymmetric of the basic flow. The parameter β in theyield stress formula of the ER fluid is shown to have distinct effectson the flow instability characteristics.

The changes in the expression of aquaporin-1 (AQP1) mRNA and protein in cultured human trabecular meshwork (HTM) cells treated with dexamethasone and transfected with antisense oligonucleotides (AS-ODN) were studied, and the implication of AQP1 regulation in corticosteroid-glaucoma and the possibility of AS-ODN inhibiting the AQP1 expression were evaluated. The cultured HTM cells in vitro were treated with different concentrations of dexamethasone and transfected with oligonucleotides for 5 days respectively. Then, total RNA and protein of HTM cells were extracted. The changes of AQP1 mRNA and protein were demonstrated qualitatively and quantitatively by RT-PCR and Western blot. Band intensities were detected by imaging analysis. There was a parallel relationship between the results of RT-PCR and those of Western blot. The expression levels of AQP1 mRNA and protein in dexamethasone-treated groups were increased initially and decreased later as dexamethasone concentration was stepped up. In the 0. 04 microg/mL and 0.4 microg/mL groups, the levels of AQP1 were higher than in control group (0 microg/mL). In the 4 microg/ mL and 40 microg/mL groups, the AQP1 expression levels were lower than in control group. AS-ODN could down-regulate the expression of AQP1 mRNA and protein in a dose-dependent manner. At 5 microg/mL, down-regulation efficiency reached the maximum. There was no statistically significant difference in the expression of AQP1 mRNA and protein between all sense oligonucleotides groups and control group. It was suggested that dexamethasone may induce the changes of the AQP1 expression in HTM cells to be involved in the occurrence of corticosteroid-glaucoma. AS-ODN can down-regulate the AQP1 expression in HTM cells to some extent.

Characteristics of cloud overlap over Eastern Asia are analyzed using a three-year dataset (2007-2009) from the cloud observing satellite CloudSat. Decorrelation depth L* (cf) is retrieved, which represents cloud overlap characteristics in the simulation of cloud-radiation processes in global climate models. Results show that values of L* (cf) in six study regions are generally within the range 0-3 km. By categorizing L* (cf) according to cloud amount in subregions, peak L* (cf) appears near subregions with cloud amount between 0.6 and 0.8. Average L* (cf) is 2.5 km. L* (cf) at higher altitudes is generally larger than at lower latitudes. Seasonal variations of L* (cf) are also clearly demonstrated. The sensitivity of cloud radiative forcing (CRF) to L* (cf) in Community Atmosphere Model 3.0 of the National Center for Atmospheric Research (CAM3/NCAR) is analyzed. The result shows that L* (cf) can have a big impact on simulation of CRF, especially in major monsoon regions and the Mid-Eastern Pacific, where the difference in CRF can reach 40-50 W m(-2). Therefore, accurate parameterization of cloud vertical overlap structure is important to CRF simulation and its feedback to climate.

The structures and thermal expansion properties of Lu2-xFexMo3O12 have been investigated by X-ray diffraction (XRD). XRD patterns at room temperature indicate that compounds Lu2-xFexMo3O12 with x <= 1.3 exhibit an orthorhombic structure with space group Pnca; compounds with x = 1.5 and 1.7 have a monoclinic structure with space group P2(1)/a. Studies on thermal expansion properties show that the linear thermal expansion coefficients of orthorhombic phase vary from negative to positive with increasing Fe content. Attempts to make zero thermal expansion materials indicate that zero thermal expansion can be observed in Lu1.3Fe0.7Mo3O12 in the temperature range of 200-400 degrees C.

The Guanshan Biota from the Cambrian Stage 4 Wulongqing Formation is a typical Burgess-shale type Lagerstatte that had witnessed the Cambrian explosion. Here we report two new localities of the Guanshan Biota, which is located at Baimei village, south of Kunming and Xinglong village, Wuding County, Yunnan Province respectively. Both localities produce soft-body fossils and several new taxa, e.g. a new species of palaeoscolecidans (Palaeoscolex xinglongensis sp. nov.) reported herein. The comparative study of the new species with similar form not only indicates that there is a diversification of palaeoscolecid species in Guanshan Biota, but also strengthens the ties between the older Chengjiang Biota and the younger Kaili Biota (and also the coeval Burgess Shale community). Three paleoecological features, including high diversity, little disparity and richness of palaeoscolecid worms, are summarized as a case study to represent the differences between Guanshan and Chengjiang Biota.