255 research outputs found
Odd C-P contributions to diffractive processes
We investigate contributions to diffractive scattering, which are odd under
C- and P-parity. Comparison of p- and p-p scattering indicates that
these odderon contributions are very small and we show how a diquark clustering
in the proton can explain this effect. A good probe for the odderon exchange is
the photo- and electroproduction of pseudo-scalar mesons. We concentrate on the
pi^0 and show that the quasi elastic pi^0-production is again strongly
suppressed for a diquark structure of the proton whereas the cross sections for
diffractive proton dissociation are larger by orders of magnitude and rather
independent of the proton structure.Comment: 18 pages, LaTex2e, graphicx package, 14 eps figures include
Vitamin D and Allergic Disease: Sunlight at the End of the Tunnel?
A role for vitamin D in the regulation of immune function was first proposed after the identification of Vitamin D Receptors in lymphocytes. It has since been recognized that the active form of vitamin D, 1α,25(OH)2D3, has direct affects on naïve and activated helper T cells, regulatory T cells, activated B cells and dendritic cells. There is a growing body of literature linking vitamin D (serum 25(OH)D, oral intake and surrogate indicators such as latitude) to various immune-related conditions, including allergy, although the nature of this relationship is still unclear. This review explores the findings of epidemiological, clinical and laboratory research, and the potential role of vitamin D in promoting the inappropriate immune responses which underpin the rise in a broad range of immune diseases
Clinical Utility of Molecular Profiling in Recurrent Glioblastoma Multiforme
Introduction: Glioblastoma multiforme (GBM) is the most common and aggressive primary malignant brain tumor found in adults. GBM has limited therapeutic options. Initial tumor sampling establishes the histopathologic diagnosis, identifies prognostic and therapeutic biomarkers, and provides an opportunity for molecular profiling. By contrast, the utility of repeat tumor sampling and molecular profiling in recurrent GBM is not well established.
Clinical Findings: We present a 69-year-old woman with GBM whose tumor recurred after standard treatment with temozolomide (TMZ) and concurrent radiation, followed by adjuvant TMZ. This patient had a methylated O6-methylguanine-DNA methyltransferase (MGMT) promoter, which ordinarily predicts a favorable response to TMZ.
Main Diagnosis, Therapeutic Interventions, and Outcomes: Our patient’s recurrent tumor was rechallenged with TMZ based on persistent methylation of the MGMT promoter. However, her tumor was refractory to TMZ, and she floridly progressed through multiple treatments. We performed retrospective molecular profiling using next-generation sequencing (NGS) on her recurrent tumor. The NGS results showed a TMZ hypermutation signature that confers resistance to TMZ. This signature impacted our patient’s treatment plan in real time and prompted an immediate discontinuation of TMZ.
Conclusions: Advances in NGS provide further insight into the molecular landscape of GBM. As NGS becomes more timely and cost-effective, molecular profiling of recurrent tumors could impact treatment decisions through either avoiding a particular treatment paradigm or identifying a potential targetable mutation. For this reason, we suggest that clinical practice routinely consider repeat biopsy and molecular profiling for recurrent GBM
Вклад Полетики М. Ф. в развитие Томской научной школы резания металлов
В статье рассмотрена биография и научная деятельность великого Томского ученого М. Ф. Полетики. Представлены основные научные достижения.The article examines the biography and scientific activities of the great Tomsk scientist M. F. Poletika. The main scientific achievements are presented
Diffractive color-dipole nucleon scattering
We determine the diffractive scattering amplitude of a color-dipole on a
nucleon using a non-perturbative model of QCD which contains only parameters
taken from low-energy physics. This allows to relate specific features of the
confinement mechanisms with diffractive electro-production processes and
structure functions. The agreement with phenomenological data is satisfactory.Comment: 7 pages, 5 eps-figures, uses eps
Two Photon Reactions at High Energies
Cross sections for the reactions gamma^(*) gamma^(*) --> hadrons and
gamma^(*) gamma^(*) --> 2 vector mesons are calculated as functions of energy
(sqrt(s) > 20 GeV) and photon virtualities. Good agreement with experiment is
obtained for the total hadronic cross section and, after allowing for a
valence-quark contribution from the hadronic part of the photon, with the
photon structure function at small x. The cross section for vector meson
production are shown to be experimentally accessible for moderate values of
Q^2. This is sufficient to probe the nature of the hard pomeron which has
recently been proposed.Comment: some changes in style, physics unchanged, final version to appear in
Phys.Rev.D, LaTeX2e, graphicx package, 15 eps-figures, 15p
Citrobacter rodentium NleB Protein Inhibits Tumor Necrosis Factor (TNF) Receptor-associated Factor 3 (TRAF3) Ubiquitination to Reduce Host Type I Interferon Production
Citation: Gao, X. F., Pham, T. H., Feuerbacher, L. A., Chen, K. M., Hays, M. P., Singh, G., . . . Hardwidge, P. R. (2016). Citrobacter rodentium NleB Protein Inhibits Tumor Necrosis Factor (TNF) Receptor-associated Factor 3 (TRAF3) Ubiquitination to Reduce Host Type I Interferon Production. Journal of Biological Chemistry, 291(35), 18232-18238. doi:10.1074/jbc.M116.738278Interferon signaling plays important roles in both intestinal homeostasis and in the host response to pathogen infection. The extent to which bacterial pathogens inhibit this host pathway is an understudied area of investigation. We characterized Citrobacter rodentium strains bearing deletions in individual type III secretion system effector genes to determine whether this pathogen inhibits the host type I IFN response and which effector is responsible. The NleB effector limited host IFN- production by inhibiting Lys(63)-linked ubiquitination of TNF receptor-associated factor 3 (TRAF3). Inhibition was dependent on the glycosyltransferase activity of NleB. GAPDH, a target of NleB during infection, bound to TRAF3 and was required for maximal TRAF3 ubiquitination. NleB glycosyltransferase activity inhibited GAPDH-TRAF3 binding, resulting in reduced TRAF3 ubiquitination. Collectively, our data reveal important interplay between GAPDH and TRAF3 and suggest a mechanism by which the NleB effector inhibits type I IFN signaling
Confining QCD Strings, Casimir Scaling, and a Euclidean Approach to High-Energy Scattering
We compute the chromo-field distributions of static color-dipoles in the
fundamental and adjoint representation of SU(Nc) in the loop-loop correlation
model and find Casimir scaling in agreement with recent lattice results. Our
model combines perturbative gluon exchange with the non-perturbative stochastic
vacuum model which leads to confinement of the color-charges in the dipole via
a string of color-fields. We compute the energy stored in the confining string
and use low-energy theorems to show consistency with the static quark-antiquark
potential. We generalize Meggiolaro's analytic continuation from parton-parton
to gauge-invariant dipole-dipole scattering and obtain a Euclidean approach to
high-energy scattering that allows us in principle to calculate S-matrix
elements directly in lattice simulations of QCD. We apply this approach and
compute the S-matrix element for high-energy dipole-dipole scattering with the
presented Euclidean loop-loop correlation model. The result confirms the
analytic continuation of the gluon field strength correlator used in all
earlier applications of the stochastic vacuum model to high-energy scattering.Comment: 65 pages, 13 figures, extended and revised version to be published in
Phys. Rev. D (results unchanged, 2 new figures, 1 new table, additional
discussions in Sec.2.3 and Sec.5, new appendix on the non-Abelian Stokes
theorem, old Appendix A -> Sec.3, several references added
Local endothelial complement activation reverses endothelial quiescence, enabling t-cell homing, and tumor control during t-cell immunotherapy.
Cancer immunotherapy relies upon the ability of T cells to infiltrate tumors. The endothelium constitutes a barrier between the tumor and effector T cells, and the ability to manipulate local vascular permeability could be translated into effective immunotherapy. Here, we show that in the context of adoptive T cell therapy, antitumor T cells, delivered at high enough doses, can overcome the endothelial barrier and infiltrate tumors, a process that requires local production of C3, complement activation on tumor endothelium and release of C5a. C5a, in turn, acts on endothelial cells promoting the upregulation of adhesion molecules and T-cell homing. Genetic deletion of C3 or the C5a receptor 1 (C5aR1), and pharmacological blockade of C5aR1, impaired the ability of T cells to overcome the endothelial barrier, infiltrate tumors, and control tumor progression in vivo, while genetic chimera mice demonstrated that C3 and C5aR1 expression by tumor stroma, and not leukocytes, governs T cell homing, acting on the local endothelium. In vitro, endothelial C3 and C5a expressions were required for endothelial activation by type 1 cytokines. Our data indicate that effective immunotherapy is a consequence of successful homing of T cells in response to local complement activation, which disrupts the tumor endothelial barrier
Magnetic string contribution to hadron dynamics in QCD
Dynamics of a light quark in the field of static source (heavy-light meson)
is studied using the nonlinear Dirac equation, derived recently. Special
attention is paid to the contribution of magnetic correlators and it is found
that it yields a significant increase of string tension at intermediate
distances. The spectrum of heavy-light mesons is computed with account of this
contribution and compared to experimental and lattice data.Comment: 10 pages Revte
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