38,396 research outputs found
A strong Oka principle for embeddings of some planar domains into CxC*
Gromov, in his seminal 1989 paper on the Oka principle, introduced the notion
of an elliptic manifold and proved that every continuous map from a Stein
manifold to an elliptic manifold is homotopic to a holomorphic map. We show
that a much stronger Oka principle holds in the special case of maps from
certain open Riemann surfaces called circular domains into CxC*, namely that
every continuous map is homotopic to a proper holomorphic embedding. An
important ingredient is a generalisation to CxC* of recent results of Wold and
Forstneric on the long-standing problem of properly embedding open Riemann
surfaces into C^2, with an additional result on the homotopy class of the
embeddings. We also give a complete solution to a question that arises
naturally in Larusson's holomorphic homotopy theory, of the existence of
acyclic embeddings of Riemann surfaces with abelian fundamental group into
2-dimensional elliptic Stein manifolds.Comment: 25 page
Expression of CXCL10 is associated with response to radiotherapy and overall survival in squamous cell carcinoma of the tongue
Five-year survival for patients with oral cancer has been disappointingly stable during the last decades, creating a demand for new biomarkers and treatment targets. Lately, much focus has been set on immunomodulation as a possible treatment or an adjuvant increasing sensitivity to conventional treatments. The objective of this study was to evaluate the prognostic importance of response to radiotherapy in tongue carcinoma patients as well as the expression of the CXC-chemokines in correlation to radiation response in the same group of tumours. Thirty-eight patients with tongue carcinoma that had received radiotherapy followed by surgery were included. The prognostic impact of pathological response to radiotherapy, N-status, T-stage, age and gender was evaluated using Cox's regression models, Kaplan-Meier survival curves and chi-square test. The expression of 23 CXC-chemokine ligands and their receptors were evaluated in all patients using microarray and qPCR and correlated with response to treatment using logistic regression. Pathological response to radiotherapy was independently associated to overall survival with a 2-year survival probability of 81 % for patients showing a complete pathological response, while patients with a non-complete response only had a probability of 42 % to survive for 2 years (p = 0.016). The expression of one CXC-chemokine, CXCL10, was significantly associated with response to radiotherapy and the group of patients with the highest CXCL10 expression responded, especially poorly (p = 0.01). CXCL10 is a potential marker for response to radiotherapy and overall survival in patients with squamous cell carcinoma of the tongue
CXCR4 Inhibition Ameliorates Severe Obliterative Pulmonary Hypertension and Accumulation of C-Kit+ Cells in Rats
Successful curative treatment of severe pulmonary arterial hypertension with luminal obliteration will require a thorough understanding of the mechanism underlying the development and progression of pulmonary vascular lesions. But the cells that obliterate the pulmonary arterial lumen in severe pulmonary arterial hypertension are incompletely characterized. The goal of our study was to evaluate whether inhibition of CXC chemokine receptor 4 will prevent the accumulation of c-kit+ cells and severe pulmonary arterial hypertension. We detected c-kit+ cells expressing endothelial (von Willebrand Factor) or smooth muscle cell/myofibroblast (α-smooth muscle actin) markers in pulmonary arterial lesions of SU5416/chronic hypoxia rats. We found increased expression of CXC chemokine ligand 12 in the lung tissue of SU5416/chronic hypoxia rats. In our prevention study, AMD3100, an inhibitor of the CXC chemokine ligand 12 receptor, CXC chemokine receptor 4, only moderately decreased pulmonary arterial obliteration and pulmonary hypertension in SU5416/chronic hypoxia animals. AMD3100 treatment reduced the number of proliferating c-kit+ α-smooth muscle actin+ cells and pulmonary arterial muscularization and did not affect c-kit+ von Willebrand Factor+ cell numbers. Both c-kit+ cell types expressed CXC chemokine receptor 4. In conclusion, our data demonstrate that in the SU5416/chronic hypoxia model of severe pulmonary hypertension, the CXC chemokine receptor 4-expressing c-kit+ α-smooth muscle actin+ cells contribute to pulmonary arterial muscularization. In contrast, vascular lumen obliteration by c-kit+ von Willebrand Factor+ cells is largely independent of CXC chemokine receptor 4
Use of minimum risk approach in the estimation of regression models with missing observation
This article considers a linear regression model with some missing observations on the response variable and presents two estimators of regression coefficients employing the approach of minimum risk estimation. Asymptotic properties of these estimators along with the traditional unbiased estimator are analyzed and conditions, that are easy to check in practice, for the superiority of one estimator over the other are derived
Chandra News
The Chandra Newsletter contains articles about the CXC and the Chandra mission. The Chandra Newsletter appears once a year and is edited by Paul J. Green, with editorial assistance and layout by Evan Tingle. We welcome contributions from readers. Comments on the newsletter, or corrections and additions to the hardcopy mailing list should be sent to: [email protected]
Comparative study of CXC chemokines modulation in brown trout (Salmo trutta) following infection with a bacterial or viral pathogen
Acknowledgements We would like to acknowledge Richard Paley, Tom Hill and Georgina Rimmer for their collaboration during brown trout infection challenges in CEFAS-Weymouth biosecurity facilities. Bartolomeo Gorgoglione, Stephen W. Feist and Nick G. H. Taylor were supported by a DEFRA grant (F1198).Peer reviewedPostprin
Finite type coarse expanding conformal dynamics
We continue the study of non-invertible topological dynamical systems with
expanding behavior. We introduce the class of {\em finite type} systems which
are characterized by the condition that, up to rescaling and uniformly bounded
distortion, there are only finitely many iterates. We show that subhyperbolic
rational maps and finite subdivision rules (in the sense of Cannon, Floyd,
Kenyon, and Parry) with bounded valence and mesh going to zero are of finite
type. In addition, we show that the limit dynamical system associated to a
selfsimilar, contracting, recurrent, level-transitive group action (in the
sense of V. Nekrashevych) is of finite type. The proof makes essential use of
an analog of the finiteness of cone types property enjoyed by hyperbolic
groups.Comment: Updated versio
Thurston obstructions and Ahlfors regular conformal dimension
Let be an expanding branched covering map of the sphere to
itself with finite postcritical set . Associated to is a canonical
quasisymmetry class \GGG(f) of Ahlfors regular metrics on the sphere in which
the dynamics is (non-classically) conformal. We show \inf_{X \in \GGG(f)}
\hdim(X) \geq Q(f)=\inf_\Gamma \{Q \geq 2: \lambda(f_{\Gamma,Q}) \geq 1\}.
The infimum is over all multicurves . The map
is defined by where the second sum is over all preimages
of freely homotopic to in , and is its Perron-Frobenius leading eigenvalue. This
generalizes Thurston's observation that if , then there is no
-invariant classical conformal structure.Comment: Minor revisions are mad
The Nature of Asymmetry in Fluid Criticality
By combining accurate liquid-vapor coexistence and heat-capacity data, we
have unambiguously separated two non-analytical contributions of liquid-gas
asymmetry in fluid criticality and proved the validity of "complete scaling"
[Fisher et al., Phys. Rev. Lett. 85, 696 (2000); Phys. Rev. E, 67, 061506,
(2003)]. We have also developed a method to obtain two scaling-field
coefficients, responsible for the two sources of the asymmetry, from mean-field
equations of state. Since the asymmetry effects are completely determined by
Ising critical exponents, there is no need for a special renormalization-group
theoretical treatment of asymmetric fluid criticality.Comment: 4 pages, 3 figure
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