627 research outputs found
Finding chinatown : ethnocentrism and urban planning
British planning and urban policy making has long had an engagement with Chinese culture, whether in terms of formulating its practices or in its understandings of the environment. The status of this relationship, however, is one that is difficult to pin down, as what often arises is a sense where Chinese culture is held, on one hand, as a source of inspiration and, on the other, in contempt
Laser gas-discharge absorption measurements of the ratio of two transition rates in argon
The ratio of two line strengths at 922.7 nm and 978.7 nm of argon is measured
in an argon pulsed discharge with the use of a single-mode Ti:Sapphire laser.
The result 3.29(0.13) is in agreement with our theoretical prediction 3.23 and
with a less accurate ratio 2.89(0.43) from the NIST database.Comment: 5 pages, 2 figures, 1 tabl
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Development of a simple nonlinear switched reluctance motor model using measured flux linkage data and curve fit
This paper presents the formulation and simulation of a simple nonlinear switched reluctance motor (SRM) model. The model formulation is developed by first measuring the motor's flux linkage. A suitable 3 dimension shape function is developed to curve fit this data. Multiple shape functions are added together to reduce the mean square error of the flux linkage equation. We call this equation the Chan Series. Motor parameters such as inductance and back electromotive force coefficient equations are obtained by differentiating the Chan Series. The coenergy and motor torque equations are derived from the Chan Series by mathematical manipulation. Nonlinear model analysis is then carried out. Ways to indicate the motor size that takes into consideration the effect of magnetic flux saturation are proposed. Two motor relations are presented. Computer simulation of the model for chop, singlechop, and single-pulse modes are performed and compared to those published in [19]. The comparisons show that the developed model can predict the SRM behavior.Center for Electromechanic
Bianchi type I space and the stability of inflationary Friedmann-Robertson-Walker space
Stability analysis of the Bianchi type I universe in pure gravity theory is
studied in details. We first derive the non-redundant field equation of the
system by introducing the generalized Bianchi type I metric. This non-redundant
equation reduces to the Friedmann equation in the isotropic limit. It is shown
further that any unstable mode of the isotropic perturbation with respect to a
de Sitter background is also unstable with respect to anisotropic
perturbations. Implications to the choice of physical theories are discussed in
details in this paper.Comment: 5 pages, some comment adde
Friedmann Equation and Stability of Inflationary Higher Derivative Gravity
Stability analysis on the De Sitter universe in pure gravity theory is known
to be useful in many aspects. We first show how to complete the proof of an
earlier argument based on a redundant field equation. It is shown further that
the stability condition applies to Friedmann-Robertson-Walker spaces
based on the non-redundant Friedmann equation derived from a simple effective
Lagrangian. We show how to derive this expression for the Friedmann equation of
pure gravity theory. This expression is also generalized to include scalar
field interactions.Comment: Revtex, 6 pages, Add two more references, some typos correcte
Lorentz-CPT violation, radiative corrections and finite temperature
In this work we investigate the radiatively induced Chern-Simons-like terms
in four-dimensions at zero and finite temperature. We use the approach of
rationalizing the fermion propagator up to the leading order in the
CPT-violating coupling . In this approach, we have shown that although
the coefficient of Chern-Simons term can be found unambiguously in different
regularization schemes at zero or finite temperature, it remains undetermined.
We observe a correspondence among results obtained at finite and zero
temperature.Comment: To appear in JHEP, 10 pages, 1 eps figure, minor changes and
references adde
Isobutyl acetate: electronic state spectroscopy by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy and ab initio calculations
The high-resolution vacuum ultraviolet photoabsorption spectrum of isobutyl acetate, C6H12O2, is presented here and was measured over the energy range 4.3â10.8 eV (290â115 nm). Valence and Rydberg transitions with their associated vibronic series have been observed in the photoabsorption spectrum and are assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. The measured photoabsorption cross sections have been used to calculate the photolysis lifetime of this ester in the Earthâs upper atmosphere (20â50 km). Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of isobutyl acetate and are compared with a photoelectron spectrum (from 9.5 to 16.7 eV), recorded for the first time. Vibrational structure is observed in the first photoelectron band of this molecule
Mixed configuration-interaction and many-body perturbation theory calculations of energies and oscillator strengths of J=1 odd states of neon
Ab-initio theory is developed for energies of J=1 particle-hole states of
neutral neon and for oscillator strengths of transitions from such states to
the J=0 ground state. Hole energies of low-Z neonlike ions are evaluated.Comment: 5 pages, 1 figure, 4 table
Overcoming bortezomib resistance in human B cells by anti-CD20/rituximab-mediated complement-dependent cytotoxicity and epoxyketone-based irreversible proteasome inhibitors
UNLABELLED: BACKGROUND: In clinical and experimental settings, antibody-based anti-CD20/rituximab and small molecule proteasome inhibitor (PI) bortezomib (BTZ) treatment proved effective modalities for B cell depletion in lymphoproliferative disorders as well as autoimmune diseases. However, the chronic nature of these diseases requires either prolonged or re-treatment, often with acquired resistance as a consequence. METHODS: Here we studied the molecular basis of acquired resistance to BTZ in JY human B lymphoblastic cells following prolonged exposure to this drug and examined possibilities to overcome resistance by next generation PIs and anti-CD20/rituximab-mediated complement-dependent cytotoxicity (CDC). RESULTS: Characterization of BTZ-resistant JY/BTZ cells compared to parental JY/WT cells revealed the following features: (a) 10-12 fold resistance to BTZ associated with the acquisition of a mutation in the PSMB5 gene (encoding the constitutive 5 proteasome subunit) introducing an amino acid substitution (Met45Ile) in the BTZ-binding pocket, (b) a significant 2-4 fold increase in the mRNA and protein levels of the constitutive 5 proteasome subunit along with unaltered immunoproteasome expression, (c) full sensitivity to the irreversible epoxyketone-based PIs carfilzomib and (to a lesser extent) the immunoproteasome inhibitor ONX 0914. Finally, in association with impaired ubiquitination and attenuated breakdown of CD20, JY/BTZ cells harbored a net 3-fold increase in CD20 cell surface expression, which was functionally implicated in conferring a significantly increased anti-CD20/rituximab-mediated CDC. CONCLUSIONS: These results demonstrate that acquired resistance to BTZ in B cells can be overcome by next generation PIs and by anti-CD20/rituximab-induced CDC, thereby paving the way for salvage therapy in BTZ-resistant disease
The Molecular Mechanism of B Cell Activation by toll-like Receptor Protein RP-105
The B cellâspecific transmembrane protein RP-105 belongs to the family of Drosophila toll-like
proteins which are likely to trigger innate immune responses in mice and man. Here we demonstrate that the Src-family protein tyrosine kinase Lyn, protein kinase C ÎČ I/II (PKCÎČI/II),
and Erk2-specific mitogen-activated protein (MAP) kinase kinase (MEK) are essential and
probably functionally connected elements of the RP-105âmediated signaling cascade in B cells.
We also find that negative regulation of RP-105âmediated activation of MAP kinases by membrane immunoglobulin may account for the phenomenon of antigen receptorâmediated arrest
of RP-105âmediated B cell proliferation
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