Microanatomy and ultrastructure of outer mantle epidermis of the cuttlefish,Sepia esculenta (Cephalopoda: Sepiidae)

This study describes the ultrastructural characteristics of external epidermis of mantle of Sepia esculenta using light and electron microscopy. The epidermis was thicker on the ventral surface than on the dorsal surface, with a higher secretory cell distribution on the ventral surface than on the dorsal surface. The epidermis was a single layer composed of epithelial cells, secretory cells, ciliated cells and neuroglial cells. Epithelial cells were columnar with well-developed microvilli on the free surface, and the microvilli were covered with glycocalyx. The epithelial cells were connected to the neighboring cells by tight junctions and membrane interdigitations of the apico-frontal surface. Well-developed microfilaments were arranged in a vertical direction in the cortical cytoplasm. The secretory cells were categorized into three types (A, B and C) in accordance with the light microscopical characteristics and ultrastructures of the secretory granules. The distribution of these cells was in the following order: Type A > Type B > Type C. SEM observation revealed that the secretory pore size of the Type A secretory cells was approximately 8.6 μm × 12.2 μm. Cytoplasm displayed a red color as the result of Masson's trichrome stain and H–E stain, and contained polygonal granules of approximately 1.2 μm² with a high electron density. The secretory pore size of the Type B secretory cells was approximately 10.1 μm × 12.1 μm. As the results of AB–PAS (pH 2.5) and AF–AB (pH 2.5) reactions, the cytoplasm displayed a red color. The cells contained membrane bounded secretory granules with very low electron density. The secretory pore of the Type C secretory cells was circular shape, and approximately 5.5 μm × 5.5 μm. Cytoplasm was found to be homogeneous under H–E stain and Masson's trichrome stain, and displayed a red color. As the result of AB–PAS (pH 2.5) reaction, the cytoplasm displayed a red color. The electron density of the secretory substance was the highest among the three types of secretory cells. The ciliated cells had a ciliary tuft on the free surface and were distributed throughout the mantle with the exception of the adhesive organs. Neuroglial cells were connected to the basal membrane, epithelial cells, secretory cells and nerve fibers through cytoplasmic process, and contained neurosecretory granules with high electron density within the cytoplasm.     

Three-dimensional treatment of convective flow in the earth's mantle

A three-dimensional finite-element method is used to investigate thermal convection in the earth's mantle. The equations of motion are solved implicitly by means of a fast multigrid technique. The computational mesh for the spherical problem is derived from the regular icosahedron. The calculations described use a mesh with 43,554 nodes and 81,920 elements and were run on a Cray X. The earth's mantly is modeled as a thick spherical shell with isothermal, free-slip boundaries. The infinite Prandtl number problem is formulated in terms of pressure, density, absolute temperature, and velocity and assumes an isotropic Newtonian rheology. Solutions are obtained for Rayleigh numbers up to approximately 10⁶ for a variety of modes of heating. Cases initialized with a temperature distribution with warmer temperatures beneath spreading ridges and cooler temperatures beneath present subduction zones yield whole-mantle convection solutions with surface velocities that correlate well with currently observed plate velocities.     

Bifurcation phenomena in a convection problem with temperature dependent viscosity at low aspect ratio

In this paper we analyse convective solutions of a two dimensional fluid layer in which viscosity depends exponentially on temperature. This problem takes in features of mantle convection, since large viscosity variations are to be expected in the Earth’s interior. These solutions are compared with solutions obtained at constant viscosity. Special attention is paid to the influence of the aspect ratio in the solutions presented. The analysis is assisted by bifurcation techniques such as branch continuation, which has proven to be a useful, systematic method for gaining insight into the possible stationary solutions satisfied by the basic equations. One feature presented by the fluid with non constant viscosity is the presence of pitchfork and saddle-node subcritical bifurcations and the presence of convective solutions below the linear critical threshold. The analysis also provides limits of existence of stationary solutions and draws the boundaries for time dependent convection.     

Combined RNA-expression and 2D-PAGE-screening identifies comprehensive interaction networks affected after bortezomib or enzastaurin exposure of mantle cell lymphoma

Despite recent advances in treatment, mantle cell lymphoma (MCL) still represents a disease with dismal prognosis due to its progressive clinical course, high rate of therapy refractory cases and frequent relapses. During recent years, the proteasome inhibitor bortezomib and enzastaurin, an inhibitor of protein kinase c have been explored in MCL. In relapsed disease enzastaurin achieved disease stabilization in a subset of patients. Bortezomib in relapsed and refractory MCL achieves response rates of 30-40%. To identify signal pathways and manifold interactions regulating cellular response to molecular targeted approaches several high throughput screening methods were applied. A combined network analysis of the identified target molecules based on both RNA array expression data and a survey of cellular protein levels resulted in a unified interaction network more comprehensive (bortezomib: 394 and enzastaurin: 174 molecules) than the networks of the individual screening techniques (329/44 and 117/36 molecules respectively). Interestingly, although none of the target molecules were matched in both RNA-expression and protein level analysis they were mapped nonetheless to common pathways. Additionally, the ranking of identified pathways allowed an improved characterization of the observed induction of cell apoptosis.     

Development of a Stokes flow solver robust to large viscosity jumps using a Schur complement approach with mixed precision arithmetic

We develop an iterative solution technique for solving Stokes flow problems with smooth and discontinuous viscosity structures using a three dimensional, staggered grid finite difference discretization. Two preconditioned iterative methodologies are applied to the saddle point arising from the discrete Stokes problem. They consist of a velocity–pressure coupled approach (FC) and a decoupled, Schur complement approach (SC). Within both of these methods, we utilize either the scaled BFBt, or an identity matrix scaled by the local cell viscosity (LV) to define a preconditioner for the Schur complement. Additionally, we propose to use a mixed precision Krylov kernel to improve the convergence by reducing round-off error. In this approach, standard double precision is used during the application of the preconditioner, whilst higher precision arithmetic is used to define the matrix vector product, dot products and norms required by the Krylov method. In our Krylov kernel, we utilize quad precision arithmetic which is emulated via the double–double precision method. We consider several simplified geodynamic problems with a viscosity contrast to demonstrate the robustness and scalability of our solution methods. Through a careful choice of stopping conditions, we are able to quantitatively compare the residuals between the SC and FC approaches. We examine the trade-off relationship between the number of outer iterations required for convergence, and the computational cost per iteration, for the each solution methods. We find that it is advantageous to use the FC approach utilizing relaxed tolerances for solution of the sub-problems, combined with the LV preconditioner. We also observed that in general, the SC approach is more robust than FC and that BFBt is more robust than LV when used in our numerical experimental. In addition, our mixed precision method produces improved convergence rates of Arnoldi type Krylov subspace methods without a drastic increasing the computational time. The usage of a high precision Krylov kernel is found to be useful for the solver associated with the velocity sub-problem.     

牡蛎外套膜中微量元素含量的测定

采用原子吸收分光光度法对广东沿海五个养殖场的牡蛎外套膜和内脏团中微量元素含量进行测定，并对其测定结果作初步探讨．发现测定牡蛎外套膜中微量元素的含量也能反映环境污染的情况及生物体内的富集情况．     

Light-Lithophile Element Metasomatism of Finero Peridotite (W ALPS): A Secondary-Ion Mass Spectrometry Study

The high sensitivity of Secondary-Ion Mass Spectrometry (SIMS) in determining very low trace-element concentrations (down to few ppb wt) has been used to address the important issue of the Light-Lithophile Element (LLE) signatures of mantle peridotites and their potential utility as tracers of transfer of subducted material into the overlying mantle wedge operated either by slab-related fluids or melts. The effects of such metasomatic agents have been described and interpreted on the basis of geochemical and isotopic characteristics of peridotites. However, direct observation of metasomatic processes occurring in the mantle is limited because the most highly metasomatised peridotites are usually found as xenoliths which do not allow large-scale chemical information. In this context, the Finero phlogopite-peridotite massif (Ivrea-Verbano Zone, western Italian Alps) offers a unique opportunity because it contains hydrous mineral assemblages (amphibole + phlogopite ± apatite) and trace element enrichments, supposed to be related to the pervasive migration of slab-derived melts. In this study we report the results of texture-related SIMS investigations performed on a wide range of trace elements such as Li, B, Large-Ion Lithophile Elements (LILE), Rare Earth Elements (REE), Nb, Zr, Ti on clinopyroxenes from the Finero peridotite. SIMS analyses revealed unusual LLE signatures that highlight the role of crust-derived components and open new perspectives on the timing of metasomatic processes.