1,391 research outputs found
The use of the asymptotic expansion to speed up the computation of a series of spherical harmonics
When a function is expressed as an infinite series of spherical harmonics the convergence can be accelerated by subtracting its asymptotic expansion and adding it in analytically closed form. In the present article this technique is applied to two biophysical cases: to the potential distribution in a spherically symmetric volume conductor and to the covariance matrix of biomagnetic measurements
The use of the asymptotic expansion to speed up the computation of a series of spherical harmonics
When a function is expressed as an infinite series of spherical harmonics the convergence can be accelerated by subtracting its asymptotic expansion and adding it in analytically closed form. In the present article this technique is applied to two biophysical cases: to the potential distribution in a spherically symmetric volume conductor and to the covariance matrix of biomagnetic measurements
Rho-omega mixing in asymmetric nuclear matter via QCD sum rule approach
We evaluate the operator product expansion (OPE) for a mixed correlator of
the isovector and isoscalar vector currents in the background of the nucleon
density with intrinsic isospin asymmetry [i.e. excess of neutrons over protons]
and match it with its imaginary part, given by resonances and continuum, via
the dispersion relation. The leading density-dependent contribution to
mixing is due the scattering term, which turns out to be larger
than any density dependent piece in the OPE. We estimate that the asymmetric
density of induces the amplitude
of mixing, equal in magnitude to the mixing amplitude in vacuum,
with the constructive interference for positive and destructive for negative
values of . We revisit sum rules for vector meson masses at finite
nucleon density to point out the numerical importance of the screening term in
the isoscalar channel, which turns out to be one order of magnitude larger than
any density-dependent condensates over the Borel window. This changes the
conclusions about the density dependence of , indicating
MeV increase at nuclear saturation density.Comment: 8 pages, Revte
Strangephilic Higgs Bosons in the MSSM
We suggest a new CPX-derived scenario for the search of strangephilic MSSM
Higgs bosons at the Tevatron and the LHC, in which all neutral and charged
Higgs bosons decay predominantly into pairs of strange quarks and into a
strange and a charm quark, respectively. The proposed scenario is realized
within a particular region of the MSSM parameter space and requires large
values of tan(beta), where threshold radiative corrections are significant to
render the effective strange-quark Yukawa coupling dominant. Experimental
searches for neutral Higgs bosons based on the identification of b-quark jets
or tau leptons may miss a strangephilic Higgs boson and its existence could be
inferred indirectly by searching for hadronically decaying charged Higgs
bosons. Potential strategies and experimental challenges to search for
strangephilic Higgs bosons at the Tevatron and the LHC are discussed.Comment: 18 pages, 7 eps figures, additional comments and references added,
version as to appear in European Physical Journal
Collagen-chitosan scaffold modified with Au and Ag nanoparticles: Synthesis and structure
Nowadays, the dermal biomimetic scaffolds are widely used in regenerative medicine. Collagen-chitosan scaffold one of these materials possesses antibacterial activity, good compatibility with living tissues and has been already used as a wound-healing material. In this article, collagen-chitosan scaffolds modified with Ag and Au nanoparticles have been synthesized using novel method - the metal-vapor synthesis. The nanocomposite materials are characterized by XPS, TEM, SEM and synchrotron radiation-based X-ray techniques. According to XRD data, the mean size of the nanoparticles (NPs) is 10.5 nm and 20.2 nm in Au-Collagen-Chitosan (Au-CollCh) and Ag-Collagen-Chitosan (Ag-CollCh) scaffolds, respectively in fair agreement with the TEM data. SAXS analysis of the composites reveals an asymmetric size distribution peaked at 10 nm for Au-CollCh and 25 nm for Ag-CollCh indicative of particle's aggregation. According to SEM data, the metal-carrying scaffolds have layered structure and the nanoparticles are rather uniformly distributed on the surface material. XPS data indicate that the metallic nanoparticles are in their unoxidized/neutral states and dominantly stabilized within the chitosan-rich domains. © 2016 Elsevier B.V. All rights reserved
Prospectus, September 6, 1989
https://spark.parkland.edu/prospectus_1989/1018/thumbnail.jp
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
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