Self-similar static solutions admitting a two-space of constant curvature

A recent result by Haggag and Hajj-Boutros is reviewed within the framework of self-similar space-times, extending, in some sense, their results and presenting a family of metrics consisting of all the static spherically symmetric perfect fluid solutions admitting a homothety.Comment: 6 page

Mesenchymal and stemness transdifferentiation via in-vitro infection of T24 cell line with Klebsiella pneumoniae

أثبتت الدراسات الحديثة أن وجود البكتيريا داخل أنسجة الورم له أثرعلى بيئة الورم وبالتالي يؤثرفى سلوك السرطان وتطوره واستجابة الخلايا  للعلاج. فى هذا البحث تم دراسة التحول التمايزى لخلايا سرطان المثانة الظاهرية الى خلايا ميزنكيمية و خلايا جذعية نتيجة لاحداث العدوى البكتيرية. وذلك من خلال إحداث عدوى لسلالة خلايا سرطان المثانة البولية (T24) ببكتيريا الكلبسيلا الرئوية لمدة يومين وأربعة أيام. تم قياس التعبير الجينى باستخدام جهاز البلمرة المتسلسل.وأظهرت النتائج زيادة في صفات الخلايا الميزنكيمية ؛ فزاد التعبير الجينى لجين الفيمنتين ، ونقص التعبيرالجينى للسيتوكيراتين، وعزز تحليل كيمياء الهيستولوجية المناعية هذه النتيجة. علاوة على ذلك، زاد التعبيرالجينى للجينات الدالة على الخلايا الجذعية. العدوى البكتيرية للخلايا السرطانية قد تسبب التمايز الخلوى، مما قد يؤدى الى تحسن قدرة الخلايا السرطانية على الانتشار والتجدد الذاتي. وبالتالي، قد تساهم البكتيريا في تطور سرطان المثانة وإنتشاره.Klebsiella pneumoniae has been found in the urinary tract of some bladder cancer patients. Bacterial presence within tumor tissue may affect the tumor-microenvironment and consequently influence cancer behavior, development, and treatment response. This study investigated mesenchymal and stemness transdifferentiation of bladder cancer cell line due to environmental stress of K. pneumoniae. Cultures of urothelial bladder cancer cell line (T24) were infected with K. pneumoniae with different multiplicity of infection (MOI) for two and four days. Transdifferentiation-associated features were morphologically assessed. Moreover, transdifferentiation markers were estimated using Q-PCR and immunohistochemistry. Q-PCR data showed an increase in mesenchymal transdifferentiation traits; vimentin expression was upregulated, and cytokeratin19 expression downregulated significantly (P<0.001) compared with controls, which were emphasized by immunohistochemistry results. Moreover, stemness transdifferentiation markers expression increased significantly (P<0.001). The heterogeneous tumor cell population may be altered by bacterial infection, which improves cancer cells' migration and self-renewal ability. Thus, bacteria may be engaged in cancer progression and metastases.

Relativistic Compact Objects in Isotropic Coordinates

We present a matrix method for obtaining new classes of exact solutions for Einstein's equations representing static perfect fluid spheres. By means of a matrix transformation, we reduce Einstein's equations to two independent Riccati type differential equations for which three classes of solutions are obtained. One class of the solutions corresponding to the linear barotropic type fluid with an equation of state $p=\gamma \rho$ is discussed in detail.Comment: 9 pages, no figures, accepted for publication in Pramana-Journal of Physic

Kinematic self-similar locally rotationally symmetric models

A brief summary of results on kinematic self-similarities in general relativity is given. Attention is focussed on locally rotationally symmetric models admitting kinematic self-similar vectors. Coordinate expressions for the metric and the kinematic self-similar vector are provided. Einstein's field equations for perfect fluid models are investigated and all the homothetic perfect fluid solutions admitting a maximal four-parameter group of isometries are given.Comment: 12 pages, LaTeX, final version, to appear in Class. Quantum Gra

Levi-Civita Solutions Coupled with Electromagnetic Fields

The local and global properties of the Levi-Civita (LC) solutions coupled with an electromagnetic field are studied and some limits to the vacuum LC solutions are given. By doing such limits, the physical and geometrical interpretations of the free parameters involved in the solutions are made clear. Sources for both the LC vacuum solutions and the LC solutions coupled with an electromagnetic field are studied, and in particular it is found that all the LC vacuum solutions with $\sigma \ge 0$ can be produced by cylindrically symmetric thin shells that satisfy all the energy conditions, weak, dominant, and strong. When the electromagnetic field is present, the situation changes dramatically. In the case of a purely magnetic field, all the solutions with $\sigma \ge 1/\sqrt{8}$ or $\sigma \le - 1/\sqrt{8}$ can be produced by physically acceptable cylindrical thin shells, while in the case of a purely electric field, no such shells are found for any value of $\sigma$.Comment: Typed in Revtex, including two figure

Static solutions of Einstein's equations with cylindrical symmetry

In analogy with the standard derivation of the Schwarzschild solution, we find all static, cylindrically symmetric solutions of the Einstein field equations for vacuum. These include not only the well known cone solution, which is locally flat, but others in which the metric coefficients are powers of the radial coordinate and the space-time is curved. These solutions appear in the literature, but in different forms, corresponding to different definitions of the radial coordinate. Because all the vacuum solutions are singular on the axis, we attempt to match them to "interior" solutions with nonvanishing energy density and pressure. In addition to the well known "cosmic string" solution joining on to the cone, we find some numerical solutions that join on to the other exterior solutions.Comment: 16 pages, 5 figures, 3 tables; many literature citations removed from main body; added historical section to put project into context and include additional reference