A finite element formulation of the Boltzmann transport equation

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Antigen presenting capacity of murine splenic myeloid cells

BACKGROUND: The spleen is an important site for hematopoiesis. It supports development of myeloid cells from bone marrow-derived precursors entering from blood. Myeloid subsets in spleen are not well characterised although dendritic cell (DC) subsets are clearly defined in terms of phenotype, development and functional role. Recently a novel dendritic-like cell type in spleen named ‘L-DC’ was distinguished from other known dendritic and myeloid cells by its distinct phenotype and developmental origin. That study also redefined splenic eosinophils as well as resident and inflammatory monocytes in spleen. RESULTS: L-DC are shown to be distinct from known splenic macrophages and monocyte subsets. Using a new flow cytometric procedure, it has been possible to identify and isolate L-DC in order to assess their functional competence and ability to activate T cells both in vivo and in vitro. L-DC are readily accessible to antigen given intravenously through receptor-mediated endocytosis. They are also capable of CD8(+) T cell activation through antigen cross presentation, with subsequent induction of cytotoxic effector T cells. L-DC are MHCII(−) cells and unable to activate CD4(+) T cells, a property which clearly distinguishes them from conventional DC. The myeloid subsets of resident monocytes, inflammatory monocytes, neutrophils and eosinophils, were found to have varying capacities to take up antigen, but were uniformly unable to activate either CD4(+) T cells or CD8(+) T cells. CONCLUSION: The results presented here demonstrate that L-DC in spleen are distinct from other myeloid cells in that they can process antigen for CD8(+) T cell activation and induction of cytotoxic effector function, while both L-DC and myeloid subsets remain unable to activate CD4(+) T cells. The L-DC subset in spleen is therefore distinct as an antigen presenting cell

Pengiraan Persentil Taburan Panjang Larian bagi Carta Kawalan Purata Bergerak Berpemberat Eksponen Multivariat

Prabhu dan Runger (1997) telah mengemukakan cadangan dalam pemilihan parameter-parameter untuk skema carta kawalan purata bergerak berpemberat eksponen multivariat (MEWMA). Walau bagaimanapun, cadangan tersebut hanya berdasarkan prestasi panjang larian purata (average run length - ARL). Oleh itu, dalam makalah ini, kami akan mengira nilai-nilai persentil untuk taburan panjang larian bagi pelbagai skema carta kawalan MEWMA yang dikemukakan oleh Prabhu dan Runger (1997). Persentil-persentil yang dikira akan membekalkan maklumat tambahan seperti kekerapan isyarat luar kawalan palsu yang awal (early false out of control signals), panjang larian median (median run length - MRL) dan kepencongan taburan panjang larian untuk sesuatu skema tertentu. Maklumat-maklumat tambahan ini mungkin berguna dalam membekalkan jurutera kawalan mutu pengetahuan mendalam dan lengkap tentang sesuatu skema carta kawalan MEWMA yang dipilih berdasarkan cadangan Prabhu dan Runger (1997)

The Use of Carboxyfluorescein Diacetate Succinimidyl Ester (CFSE) to Monitor Lymphocyte Proliferation

Carboxyfluorescein succinimidyl ester (CFSE) is an effective and popular means to monitor lymphocyte division1-3. CFSE covalently labels long-lived intracellular molecules with the fluorescent dye, carboxyfluorescein. Thus, when a CFSE-labeled cell divides, its progeny are endowed with half the number of carboxyfluorescein-tagged molecules and thus each cell division can be assessed by measuring the corresponding decrease in cell fluorescence via Flow cytometry. The capacity of CFSE to label lymphocyte populations with a high fluorescent intensity of exceptionally low variance, coupled with its low cell toxicity, make it an ideal dye to measure cell division. Since it is a fluorescein-based dye it is also compatible with a broad range of other fluorochromes making it applicable to multi-color flow cytometry. This article describes the procedures typically used for labeling mouse lymphocytes for the purpose of monitoring up to 8 cell divisions. These labeled cells can be used both for in vitro and in vivo studies

Bystander B cells rapidly acquire antigen receptors from activated B cells by membrane transfer: a novel mechanism for enhancing specific antigen presentation

The B cell antigen receptor (BCR) efficiently facilitates the capture and processing of a specific antigen for presentation on MHC class II molecules to antigen specific CD4+ T cells (1). Despite this, the majority of B cells are only thought to play a limited role in CD4+ T cell activation since BCRs are clonotypically expressed. Here we show, however, that activated B cells can, both in vitro and in vivo, rapidly donate their BCR to bystander B cells, a process that is mediated by direct membrane transfer between adjacent B cells and is amplified by the interaction of the BCR with specific antigen. This results in a dramatic expansion in the number of antigen-binding B cells in vivo, with the transferred BCR endowing recipient B cells with the ability to present specific antigen to antigen-specific CD4+ T cells

The Use of CFSE-like Dyes for Measuring Lymphocyte Proliferation : Experimental Considerations and Biological Variables

The measurement of CFSE dilution by flow cytometry is a powerful experimental tool to measure lymphocyte proliferation. CFSE fluorescence precisely halves after each cell division in a highly predictable manner and is thus highly amenable to mathematical modelling. However, there are several biological and experimental conditions that can affect the quality of the proliferation data generated, which may be important to consider when modelling dye dilution data sets. Here we overview several of these variables including the type of fluorescent dye used to monitor cell division, dye labelling methodology, lymphocyte subset differences, in vitro versus in vivo experimental assays, cell autofluorescence, and dye transfer between cells.This work was supported by a Project Grant to BQ and CP and a Program Grant to CP from the National Health and Medical Research Council (NHMRC) of Australia

Anisotropic diffusion in continuum relaxation of stepped crystal surfaces

We study the continuum limit in 2+1 dimensions of nanoscale anisotropic diffusion processes on crystal surfaces relaxing to become flat below roughening. Our main result is a continuum law for the surface flux in terms of a new continuum-scale tensor mobility. The starting point is the Burton, Cabrera and Frank (BCF) theory, which offers a discrete scheme for atomic steps whose motion drives surface evolution. Our derivation is based on the separation of local space variables into fast and slow. The model includes: (i) anisotropic diffusion of adsorbed atoms (adatoms) on terraces separating steps; (ii) diffusion of atoms along step edges; and (iii) attachment-detachment of atoms at step edges. We derive a parabolic fourth-order, fully nonlinear partial differential equation (PDE) for the continuum surface height profile. An ingredient of this PDE is the surface mobility for the adatom flux, which is a nontrivial extension of the tensor mobility for isotropic terrace diffusion derived previously by Margetis and Kohn. Approximate, separable solutions of the PDE are discussed.Comment: 14 pages, 1 figur

Variation of cultivated mungbean and wild vigna as revealed by random amplified polymorphic DNA markers

The genetic variation of nine varieties of cultivated mungbean (Vigna radiata) and three local populations of wild Vigna (V. trinervia) were evaluated in this study using RAPD markers. A total of 65 scorable DNA fragments ranging in size from 173-1,500 bp were obtained from the PCR amplification usingfive RAPD primers of which 95.38% were polymorphic. Cluster analysis revealed two major groups in which the first group consists of the nine varieties ofV. radiata, while the second group includes the three populations ofV. trinervia. This information is useful for plant breeders to make informed decisions in an effort to devise breeding or crossbreeding programmes for the development of the crop

catena-Poly[[sodium-di-μ-β-d-glucose] chloride]

The asymmetric unit of the title compound, {[Na(C6H12O6)2]Cl}n, contains six glucose mol­ecules, three Na+ ions and three Cl− ions, i.e. three independent {[Na(C6H12O6)2]Cl} units. Each of these units forms polymeric chains along the c axis. Each Na+ ion is surrounded by six O atoms from four glucose mol­ecules, forming a distorted octa­hedral geometry. All glucose mol­ecules adopt chair conformations. The constituent units are linked into a three-dimensional framework by O—H⋯Cl and O—H⋯O hydrogen bonds, utilizing all the O—H groups

A Diversity of Conserved and Novel Ovarian MicroRNAs in the Speckled Wood (Pararge aegeria)

microRNAs (miRNAs) are important regulators of animal development and other processes, and impart robustness to living systems through post-transcriptional regulation of specific mRNA transcripts. It is postulated that newly emergent miRNAs are generally expressed at low levels and with spatiotemporally restricted expression domains, thus minimising effects of spurious targeting on animal transcriptomes. Here we present ovarian miRNA transcriptome data for two geographically distinct populations of the Speckled Wood butterfly (Pararge aegeria). A total of 74 miRNAs were identified, including 11 newly discovered and evolutionarily-young miRNAs, bringing the total of miRNA genes known from P. aegeria up to 150. We find a positive correlation between miRNA age and expression level. A common set of 55 miRNAs are expressed in both populations. From this set, we identify seven that are consistently either ovary-specific or highly upregulated in ovaries relative to other tissues. This ‘ovary set’ includes miRNAs with known contributions to ovarian function in other insect species with similar ovaries and mode of oogenesis, including miR-989 and miR-2763, plus new candidates for ovarian function. We also note that conserved miRNAs are overrepresented in the ovary relative to the whole body