500 research outputs found
Temperature measurement in the convective and segregated vibrated bed of powder : A numerical study
In numerically simulated vibrated beds of powder, we measure temperature
under convection by the generalized Einstein's relation. The spatial
temperature distribution turns out to be quite uniform except for the boundary
layers. In addition to this, temperature remains uniform even if segregation
occurs. This suggests the possibility that there exists some "thermal
equilibrium state" even in a vibrated bed of powder. This finding may lead to a
unified view of the dynamic steady state of granular matter.Comment: Granular Matter, in press (Revised for the publication
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Immunoregulatory functions for murine intraepithelial lymphocytes: gamma/delta T cell receptor-positive (TCR+) T cells abrogate oral tolerance, while alpha/beta TCR+ T cells provide B cell help.
Past work has shown that a subset of effector T cells with unique characteristics could abrogate hapten- or antigen-induced tolerance, and the reconstitution of this immune response has been termed contrasuppression. We have studied contrasuppression in a model of oral tolerance (OT) in which adoptively transferred antigen-specific T contrasuppressor (Tcs) cells reverse OT and result in antibody responses to the eliciting antigen. In the present study, we show that murine intraepithelial lymphocytes (IELs) from mice orally immunized with sheep red blood cells (SRBC) contain T cells that exhibit Tcs cell activity. This effect was mediated by CD3+ gamma/delta T cell receptor-positive (TCR+), but not alpha/beta TCR+ T cells, and gamma/delta TCR+ Tcs cells were associated with both the CD4-,CD8+ and CD4-,CD8- (double-negative) IEL fractions. The CD4-,CD8+ gamma/delta TCR+ IELs were further separated into Vicia villosa-adherent and -nonadherent fractions. Adoptive transfer of V. villosa-adherent gamma/delta TCR+ T cells to mice with OT to SRBC resulted in splenic IgA, IgM, and IgG subclass anti-SRBC responses, while V. villosa-nonadherent gamma/delta TCR+ T cells were without activity. The gamma/delta TCR+ IELs did not support in vitro antibody responses in B cell cultures, while alpha/beta TCR+ IELs were effective T helper cells. Further, cytokine production by the gamma/delta TCR+ IELs was examined, and the gamma/delta TCR+ V. villosa-adherent fraction, which possessed contrasuppressor function, contained low levels of IL-5 mRNA and small numbers of IL-5-producing cells when compared with alpha/beta TCR+ IELs and V. villosa-nonadherent gamma/delta TCR+ IELs. Our results now show that mouse IELs contain two distinct types of T cells that function in the immune response, e.g., alpha/beta TCR+ T cells that produce IL-5 and function as helper cells, and gamma/delta TCR+ T cells that restore antibody responses in mice that had been orally tolerized with antigen
Simulation of a Dripping Faucet
We present a simulation of a dripping faucet system. A new algorithm based on
Lagrangian description is introduced. The shape of drop falling from a faucet
obtained by the present algorithm agrees quite well with experimental
observations. Long-term behavior of the simulation can reproduce period-one,
period-two, intermittent and chaotic oscillations widely observed in
experiments. Possible routes to chaos are discussed.Comment: 20 pages, 15 figures, J. Phys. Soc. Jpn. (in press
Critical Scale-invariance in Healthy Human Heart Rate
We demonstrate the robust scale-invariance in the probability density
function (PDF) of detrended healthy human heart rate increments, which is
preserved not only in a quiescent condition, but also in a dynamic state where
the mean level of heart rate is dramatically changing. This scale-independent
and fractal structure is markedly different from the scale-dependent PDF
evolution observed in a turbulent-like, cascade heart rate model. These results
strongly support the view that healthy human heart rate is controlled to
converge continually to a critical state.Comment: 9 pages, 3 figures. Phys. Rev. Lett., to appear (2004
Establishment of an immortalised human ovarian surface epithelial cell line without chromosomal instability
Epithelial ovarian carcinoma is thought to derive from ovarian surface epithelium (OSE). The black box of the early molecular changes in ovarian carcinogenesis is being interpreted by the development of experimental systems employing immortalised human OSE cells. However, the existing cell lines of the OSE cells have limited utility due to chromosomal instability. Our goal was to establish new immortalised human OSE cells that retain the original characteristics of the primary cells without chromosomal alterations. Using primary human OSE cells obtained from a postmenopausal patient with endometrial cancer, five cell lines (βHOSE1' lines) were newly established by infection with retroviral expression vectors containing type 16 human papillomavirus (HPV-16) E6, E7, a variant E6 (E6Ξ151), and Bmi1 polycomb gene, in combination with telomerase reverse transcriptase (hTERT). Consequently, five HOSE1s cell lines, HOSE1s-E6/hTERT, -E7/hTERT, -E6/E7/hTERT, -E6Ξ151/E7/hTERT, and -E6Ξ151/Bmi1/hTERT, grew beyond the population doubling number of 200. These cell lines, except for HOSE1-E6/hTERT, essentially showed the original features of the primary human OSE cells. Of them, HOSE1-E7/hTERT preserved diploidy in a kariotype analysis, and did not show transformed phenotypes in anchorage-independent growth and tumour formation. Thus, HOSE1-E7/hTERT may provide a novel model system with which to investigate the mechanisms of early molecular changes
Loss of Sialic Acid Binding Domain Redirects Protein Ο1 to Enhance M Cell-Directed Vaccination
Ovalbumin (OVA) genetically fused to protein sigma 1 (pΟ1) results in tolerance to both OVA and pΟ1. PΟ1 binds in a multi-step fashion, involving both protein- and carbohydrate-based receptors. To assess the relative pΟ1 components responsible for inducing tolerance and the importance of its sialic binding domain (SABD) for immunization, modified OVA-pΟ1, termed OVA-pΟ1(short), was deleted of its SABD, but with its M cell targeting moiety intact, and was found to be immunostimulatory and enhanced CD4+ and CD8+ T cell proliferation. When used to nasally immunize mice given with and without cholera toxin (CT) adjuvant, elevated SIgA and serum IgG responses were induced, and OVA-pΟ1(s) was more efficient for immunization than native OVA+CT. The immune antibodies (Abs) were derived from elevated Ab-forming cells in the upper respiratory tissues and submaxillary glands and were supported by mixed Th cell responses. Thus, these studies show that pΟ1(s) can be fused to vaccines to effectively elicit improved SIgA responses
A Pivotal Role of Vitamin B9 in the Maintenance of Regulatory T Cells In Vitro and In Vivo
Dietary factors regulate immunological function, but the underlying mechanisms remain elusive. Here we show that vitamin B9 is a survival factor for regulatory T (Treg) cells expressing high levels of vitamin B9 receptor (folate receptor 4). In vitamin B9-reduced condition in vitro, Treg cells could be differentiated from naΓ―ve T cells but failed to survive. The impaired survival of Treg cells was associated with decreased expression of anti-apoptotic Bcl2 and independent of IL-2. In vivo depletion of dietary vitamin B9 resulted in the reduction of Treg cells in the small intestine, a site for the absorption of dietary vitamin B9. These findings provide a new link between diet and the immune system, which could maintain the immunological homeostasis in the intestine
Preparation of porous thin-film polymethylsiloxane microparticles in a W/O emulsion system
Porous thin-film polymethylsiloxane microparticles have been prepared successfully from octyltrichlorosilane and methyltrichlorosilane in (water/oil) W/O emulsion systems by using several oil phases and changing the amount of the silanes or of the surfactant Span 60. Hollow microspheres of various shell thicknesses (120-180 nm) and high surface area were prepared by using four types of nonpolar solvents as the oil phase of the W/O emulsion system. The diameter of the spheres can also be controlled (1-1.6 mu m) by using different oil phases. The results of thermal analysis, nitrogen adsorption isotherm, infrared spectra and X-ray diffraction data showed that hollow microspheres of amorphous polymethylsiloxane with high surface area (360-385 m(2)g(-1)) can be obtained by heating the spheres in air at 673 K; the polymethylsiloxane microspheres become nonporous silica particles after calcination at 873 K for 3 h. Cup-shape microparticles of polymethylsiloxane with nano-order thickness (20-120 nm) were prepared by reducing the amount of silanes in the mixture. Small hollow particles were prepared by replacing a portion of the octyltrichlorosilane with Span 60.ArticlePOLYMER JOURNAL. 47(6): 449-455 (2015)journal articl
Infection with 2009 H1N1 influenza virus primes for immunological memory in human nose-associated lymphoid tissue, offering cross-reactive immunity to H1N1 and avian H5N1 viruses
Influenza is a highly contagious mucosal infection in the respiratory tract. 2009 pandemic H1N1 (pH1N1) virus infection resulted in substantial morbidity and mortality in humans. Little is known on whether immunological memory develops following pH1N1 infection and whether it provides protection against other virus subtypes. Enzyme-linked immunosorbent spot assay was used to analyze hemagglutinin (HA)-specific memory B cell responses after virus antigen stimulation in nasal-associated lymphoid tissues (NALT) from children and adults. Individuals with serological evidence of previous exposure to pH1N1 showed significant cross-reactive HA-specific memory B responses to pH1N1, seasonal H1N1(sH1N1) and avian H5N1(aH5N1) viruses upon pH1N1 virus stimulation. pH1N1 virus antigen elicited stronger cross-reactive memory B cell responses than sH1N1 virus. Intriguingly, aH5N1 virus also activated cross-reactive memory responses to sH1N1 and pH1N1 HAs in those who had previous pH1N1 exposure, and that correlated well with the memory response stimulated by pH1N1 virus antigen. These memory B cell responses resulted in cross-reactive neutralizing antibodies against sH1N1, 1918 H1N1 and aH5N1viruses. 2009 pH1N1 infection appeared to have primed human host with B cell memory in NALT that offers cross-protective mucosal immunity against not only H1N1 but also aH5N1 viruses. These findings may have important implications to future vaccination strategies against influenza. It will be important to induce and/or enhance such cross-protective mucosal memory B cells
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