8,942 research outputs found
Isolation, phenotype, and allostimulatory activity of mouse liver dendritic cells
Donor liver-derived dendritic cells (DC) have recently been identified within various lymphoid and nonlymphoid tissues of organ allograft recipients, including nonimmunosuppressed mice transplanted with and permanently accepting major histocompatibility complex (MHC)-disparate hepatic allografts. These findings have raised questions about the basis of the tolerogenicity of the liverāand, in particular, about the properties of liver-derived DC. To study further the structure, immunophenotype and allostimu-latory activity of leukocytes resident in normal mouse (B10.BR; H-2k, I-Ek) liver, a procedure was developed to maximize the yield of viable, nonparenchymal cells (NPC) obtained following collagenase digestion of perfused liver fragments and density centrifugation (Per-coll). These cells comprised populations expressing lymphoid and myeloid cell surface antigens. As compared with spleen cells, they proved good allostimula-tors of naive (BIO; H-2b, I-E") splenic T cells when tested in primary mixed leukocyte reactions (MLR). After overnight (18-hr) incubation of the NPC, enrichment for transiently adherent, low-density (LD) cells on metrizamide gradients permitted the recovery of low numbers of cells (approx. 2-5 Ć 105 per liver), many of which displayed distinct DC morphology. Flow cytometric analysis revealed that these cells were CD3-, CD4-, CD8-, and B220-, but strongly expressed CD45 (leukocyte-common antigen), and mild-to-moderate levels of CD lib, heat-stable antigen, and CD44. The cells also expressed moderate intensity of NLDC 145 but not 33D1, DC restricted markers which have been shown to be differentially expressed on mouse DC isolated from various organs. This DC-enriched population was more strongly MHC class II(I-Ek)+ than NPC, as determined by immunocytochemistry and flow cytometry and exhibited much more potent allo-stimulatory activity for naive T cells. These findings demonstrate that freshly isolated murine liver NPC, and perhaps their counterparts in situ, exhibit allo-stimulatory activity that is enhanced in the nonadherent, low-density (DC-enriched) fraction after overnight culture. They further suggest that the Ā© 1994 by Williams and Wilkins
Optical conductivity in the normal state fullerene superconductors
We calculate the optical conductivity, , in the normal state
fullerene superconductors by self-consistently including the impurity
scatterings, the electron-phonon and electron-electron Coulomb interactions.
The finite bandwidth of the fullerenes is explicitely considered, and the
vertex corection is included Nambu in calculating the renormalized
Green's function. is obtained by calculating the
current-current correlation function with the renormalized Green's function in
the Matsubara frequency and then performing analytic continuation to the real
frequency at finite temperature. The Drude weight in is
strongly suppressed due to the interactions and transfered to the mid-infrared
region around and above 0.06 eV which is somewhat less pronounced and much
broader compared with the expermental observation by DeGiorgi .Comment: 6 pages, 4 figures. To be published in Physical Review B, July 1
Criterion for transformation of transverse domain wall to vortex or antivortex wall in soft magnetic thin-film nanostripes
We report on the criterion for the dynamic transformation of the internal
structure of moving domain walls (DWs) in soft magnetic thin-film nanostripes
above the Walker threshold field, Hw. In order for the process of
transformation from transverse wall (TW) to vortex wall (VW) or antivortex wall
(AVW) occurs, the edge-soliton core of the TW-type DW should grow sufficiently
to the full width at half maximum of the out-of-plane magnetizations of the
core area of the stabilized vortex (or antivortex) by moving inward along the
transverse (width) direction. Upon completion of the nucleation of the vortex
(antivortex) core, the VW (AVW) is stabilized, and then its core accompanies
the gyrotropic motion in a potential well (hill) of a given nanostripe. Field
strengths exceeding the Hw, which is the onset field of DW velocity breakdown,
are not sufficient but necessary conditions for dynamic DW transformation
Gauge coupling renormalization in orbifold field theories
We investigate the gauge coupling renormalization in orbifold field theories
preserving 4-dimensional N=1 supersymmetry in the framework of 4-dimensional
effective supergravity. As a concrete example, we consider the 5-dimensional
Super-Yang-Mills theory on a slice of AdS_5. In our approach, one-loop gauge
couplings can be determined by the loop-induced axion couplings and the tree
level properties of 4-dimensional effective supergravity which are much easier
to be computed.Comment: 18 pages, JHEP style; 1-loop corrections to gauge kinetic functions
are fully computed, references are adde
iObjectify: self- and other-objectification on Grindr, a geosocial networking application designed for men who have sex with men
Grindr is a smartphone application for men who have sex with men (MSM). Despite its reputation as a āhook-up appā, little is known about its usersā self-presentation strategies and how this relates to objectification - this paper explores objectification on Grindr. The results of Study 1 showed that Grindr users objectified other men more than non-Grindr users. A content analysis of 1400 Grindr profiles in Study 2 showed that profile pictures with objectifying content were related to searching for sexual encounters. Finally, a survey of Grindr users in Study 3 revealed that objectification processes and sexualized profile pictures were related to some objectification-relevant online behaviors (e.g., increased use of Grindr, discussion of HIV status). Interestingly, the presence of body focused profile content was more related to sexual orientation disclosure (not being āoutā) than to objectification. This paper presents evidence that Grindr usage and online presentation are related to objectification processes
Impedance Characterization of a Model Au/Yttria-Stabilized Zirconia/Au Electrochemical Cell in Varying Oxygen and NO\u3csub\u3e\u3cem\u3ex\u3c/em\u3e\u3c/sub\u3e Concentrations
An electrochemical cell [Au/yttria-stabilized zirconia (YSZ)/Au] serves as a model system to investigate the effect of O2 and NOx. Possible mechanisms responsible for the response are presented. Two dense Au electrodes are co-located on the same side of a dense YSZ electrolyte and are separated from the electrolyte by a porous YSZ layer, present only under the electrodes. While not completely understood, the porous layer appears to result in enhanced NOx response. Impedance data were obtained over a range of frequencies 0.1 Hz to 1 MHz, temperatures 600ā700Ā°C, and oxygen 2ā18.9% and NOx 10ā100 ppm concentrations. Spectra were fit with an equivalent circuit, and values of the circuit elements were evaluated. In the absence of NOx, the effect of O2 on the low-frequency arc resistance could be described by a power law, and the temperature dependence by a single apparent activation energy at all O2 concentrations. When both O2 and NOx were present, however, the power-law exponent varied as a function of both temperature and concentration, and the apparent activation energy also showed dual dependence. Adsorption mechanisms are discussed as possibilities for the rate-limiting steps. Implications for impedancemetric NOx sensing are also discussed
Vacuum arc plasma thrusters with inductive energy storage driver
An apparatus for producing a vacuum arc plasma source device using a low mass, compact inductive energy storage circuit powered by a low voltage DC supply acts as a vacuum arc plasma thruster. An inductor is charged through a switch, subsequently the switch is opened and a voltage spike of Ldi/dt is produced initiating plasma across a resistive path separating anode and cathode. The plasma is subsequently maintained by energy stored in the inductor. Plasma is produced from cathode material, which allows for any electrically conductive material to be used. A planar structure, a tubular structure, and a coaxial structure allow for consumption of cathode material feed and thereby long lifetime of the thruster for long durations of time
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