11,001 research outputs found
Impact of killer-immunoglobulin-like receptor and human leukocyte antigen genotypes on the efficacy of immunotherapy in acute myeloid leukemia
Interactions between killer-immunoglobulin-like receptors (KIRs) and their HLA class I ligands are instrumental in natural killer (NK) cell regulation and protect normal tissue from NK cell attack. Human KIR haplotypes comprise genes encoding mainly inhibitory receptors (KIR A) or activating and inhibitory receptors (KIR B). A substantial fraction of humans lack ligands for inhibitory KIRs (iKIRs), that is, a 'missing ligand' genotype. KIR B/x and missing ligand genotypes may thus give rise to potentially autoreactive, unlicensed NK cells. Little is known regarding the impact of such genotypes in untransplanted acute myeloid leukemia (AML). For this study, NK cell phenotypes and KIR/HLA genotypes were determined in 81 AML patients who received immunotherapy with histamine dihydrochloride and low-dose IL-2 for relapse prevention (NCT01347996). We observed that presence of unlicensed NK cells impacted favorably on clinical outcome, in particular among patients harboring functional NK cells reflected by high expression of the natural cytotoxicity receptor (NCR) NKp46. Genotype analyses suggested that the clinical benefit of high NCR expression was restricted to patients with a missing ligand genotype and/or a KIR B/x genotype. These data imply that functional NK cells are significant anti-leukemic effector cells in patients with KIR/HLA genotypes that favor NK cell autoreactivity
Fluctuations and stability in front propagation
Propagating fronts arising from bistable reaction-diffusion equations are a
purely deterministic effect. Stochastic reaction-diffusion processes also show
front propagation which coincides with the deterministic effect in the limit of
small fluctuations (usually, large populations). However, for larger
fluctuations propagation can be affected. We give an example, based on the
classic spruce-budworm model, where the direction of wave propagation, i.e.,
the relative stability of two phases, can be reversed by fluctuations.Comment: 5 pages, 5 figure
Preliminary Measurements of the Motion of Arcjet Current Channel Using Inductive Magnetic Probes
This paper covers the design and first measurements of non-perturbative, external inductive magnetic diagnostics for arcjet constrictors which can measure the motion of the arc current channel. These measurements of arc motion are motivated by previous simulations using the ARC Heater Simulator (ARCHeS), which predicted unsteady arc motion due to the magnetic kink instability. Measurements of the kink instability are relevant to characterizing motion of the enthalpy profile of the arcjet, the arcjet operational stability, and electrode damage due to associated arc detachment events. These first measurements indicate 4 mm oscillations at 0.5-2 kHz of the current profile
Exact solutions of a restricted ballistic deposition model on a one-dimensional staircase
Surface structure of a restricted ballistic deposition(RBD) model is examined
on a one-dimensional staircase with free boundary conditions. In this model,
particles can be deposited only at the steps of the staircase. We set up
recurrence relations for the surface fluctuation width using generating
function method. Steady-state solutions are obtained exactly given system size
. In the infinite-size limit, diverges as with the scaling
exponent . The dynamic exponent
is also found to be by solving the recurrence relations
numerically. This model can be viewed as a simple variant of the model which
belongs to the Kardar-Parisi-Zhang (KPZ) universality class . Comparing its deposition time scale
with that of the single-step model, we argue that must be the same as
, which is consistent with our finding.Comment: 19 pages, REVTEX, 5 figures upon request, INHA-PHYS-94-00
Growth and forms of Laplacian aggregates
The shapes and general morphological properties of aggregates grown following the 'T/ rule
(Vsurface ex IEI") [L. Niemeyer, L. Pietronero, and H. J. Wiessmann, Phys. Rev. Lett. 52, 1033
(1984)] have been investigated. Vsurface is the velocity at the interface and E the electric field. The
fractal dimension decreases monotonically from its diffusion-limited aggregation value ('T/ = 1) to
a number indistinguishable from 1 at 'T/ ~ 4. Simultaneously, the multifractal properties become
independent of'T/. An alternative method to generate large clusters, and gain insight into the growth
process, is also presented. Various analytical approximations are discussed.
PACS number(s): 82.20.Wt, 75.10.Jm, 75.10.Lp, 75.30.DsCICyT (Spain) Project No. MAT90-0544 and the U.S. Department of Energy. L.M.S. is thankful to the NSF for financial support under Grant No. DMR 91-17249. F.G. and E.L. acknowledge support from CICyT (Spain).Publicad
Recursive internetwork architecture, investigating RINA as an alternative to TCP/IP (IRATI)
Driven by the requirements of the emerging applications and networks, the Internet has become an architectural patchwork of growing complexity which strains to cope with the changes. Moore’s law prevented us from recognising that the problem does not hide in the high demands of today’s applications but lies in the flaws of the Internet’s original design. The Internet needs to move beyond TCP/IP to prosper in the long term, TCP/IP has outlived its usefulness.
The Recursive InterNetwork Architecture (RINA) is a new Internetwork architecture whose fundamental principle is that networking is only interprocess communication (IPC). RINA reconstructs the overall structure of the Internet, forming a model that comprises a single repeating layer, the DIF (Distributed IPC Facility), which is the minimal set of components required to allow distributed IPC between application processes. RINA supports inherently and without the need of extra mechanisms mobility, multi-homing and Quality of Service, provides a secure and configurable environment, motivates for a more competitive marketplace and allows for a seamless adoption.
RINA is the best choice for the next generation networks due to its sound theory, simplicity and the features it enables. IRATI’s goal is to achieve further exploration of this new architecture. IRATI will advance the state of the art of RINA towards an architecture reference model and specifcations that are closer to enable implementations deployable in production scenarios.
The design and implemention of a RINA prototype on top of Ethernet will permit the experimentation and evaluation of RINA in comparison to TCP/IP. IRATI will use the OFELIA testbed to carry on its experimental activities. Both projects will benefit from the collaboration. IRATI will gain access to a large-scale testbed with a controlled network while OFELIA will get a unique use-case to validate the facility: experimentation of a non-IP based Internet
Takotsubo cardiomyopathy associated with anesthesia: three case reports
Takotsubo cardiomyopathy is a form of transient, reversible left ventricular dysfunction that can mimic an acute coronary event. However, cardiac catheterization often reveals normal coronary arteries. Patients are often postmenopausal women who experience acute physical or emotional distress. The prognosis for this entity is quite favorable. In this report, we present three cases of Takotsubo cardiomyopathy in patients having procedures involving anesthesia. Each case illustrates a different etiology for the syndrome: Patient, procedure, and anesthetic management
Pattern Formation of Glioma Cells: Effects of Adhesion
We investigate clustering of malignant glioma cells. \emph{In vitro}
experiments in collagen gels identified a cell line that formed clusters in a
region of low cell density, whereas a very similar cell line (which lacks an
important mutation) did not cluster significantly. We hypothesize that the
mutation affects the strength of cell-cell adhesion. We investigate this effect
in a new experiment, which follows the clustering dynamics of glioma cells on a
surface. We interpret our results in terms of a stochastic model and identify
two mechanisms of clustering. First, there is a critical value of the strength
of adhesion; above the threshold, large clusters grow from a homogeneous
suspension of cells; below it, the system remains homogeneous, similarly to the
ordinary phase separation. Second, when cells form a cluster, we have evidence
that they increase their proliferation rate. We have successfully reproduced
the experimental findings and found that both mechanisms are crucial for
cluster formation and growth.Comment: 6 pages, 6 figure
Chemical kinetics and photochemical data for use in stratospheric modeling
As part of a series of evaluated sets, rate constants and photochemical cross sections compiled by the NASA Panel for Data Evaluation are provided. The primary application of the data is in the modeling of stratospheric processes, with particular emphasis on the ozone layer and its possible perturbation by anthropogenic and natural phenomena. Copies of this evaluation are available from the Jet Propulsion Laboratory
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