146 research outputs found

    Limits to differences in active and passive charges

    Get PDF
    We explore consequences of a hypothetical difference between active charges, which generate electric fields, and passive charges, which respond to them. A confrontation to experiments using atoms, molecules, or macroscopic matter yields limits on their fractional difference at levels down to 10^-21, which at the same time corresponds to an experimental confirmation of Newtons third law.Comment: 6 pages Revtex. To appear in Phys. Rev.

    Testing the neutrality of matter by acoustic means in a spherical resonator

    Full text link
    New measurements to test the neutrality of matter by acoustic means are reported. The apparatus is based on a spherical capacitor filled with gaseous SF6_6 excited by an oscillating electric field. The apparatus has been calibrated measuring the electric polarizability. Assuming charge conservation in the β\beta decay of the neutron, the experiment gives a limit of ϵp-e11021\epsilon_\text{p-e}\lesssim1\cdot10^{-21} for the electron-proton charge difference, the same limit holding for the charge of the neutron. Previous measurements are critically reviewed and found incorrect: the present result is the best limit obtained with this technique

    Constraints on the Electrical Charge Asymmetry of the Universe

    Full text link
    We use the isotropy of the Cosmic Microwave Background to place stringent constraints on a possible electrical charge asymmetry of the universe. We find the excess charge per baryon to be qep<1026eq_{e-p}<10^{-26}e in the case of a uniform distribution of charge, where ee is the charge of the electron. If the charge asymmetry is inhomogeneous, the constraints will depend on the spectral index, nn, of the induced magnetic field and range from qep<5×1020eq_{e-p}<5\times 10^{-20}e (n=2n=-2) to qep<2×1026eq_{e-p}<2\times 10^{-26}e (n2n\geq 2). If one could further assume that the charge asymmetries of individual particle species are not anti-correlated so as to cancel, this would imply, for photons, qγ<1035eq_\gamma< 10^{-35}e; for neutrinos, qν<4×1035eq_\nu<4\times10^{-35}e; and for heavy (light) dark matter particles qdm<4×1024eq_{\rm dm}<4\times10^{-24}e (qdm<4×1030eq_{\rm dm}<4\times10^{-30}e).Comment: New version to appear in JCA

    Neutral Particles in Light of the Majorana-Ahluwalia Ideas

    Get PDF
    The first part of this article (Sections I and II) presents oneself an overview of theory and phenomenology of truly neutral particles based on the papers of Majorana, Racah, Furry, McLennan and Case. The recent development of the construct, undertaken by Ahluwalia [{\it Mod. Phys. Lett. A}{\bf 9} (1994) 439; {\it Acta Phys. Polon. B}{\bf 25} (1994) 1267; Preprints LANL LA-UR-94-1252, LA-UR-94-3118], could be relevant for explanation of the present experimental situation in neutrino physics and astrophysics. In Section III the new fundamental wave equations for self/anti-self conjugate type-II spinors, proposed by Ahluwalia, are re-casted to covariant form. The connection with the Foldy-Nigam-Bargmann-Wightman- Wigner (FNBWW) type quantum field theory is found. The possible applications to the problem of neutrino oscillations are discussed.Comment: REVTEX file. 21pp. No figure

    Interference with glycosaminoglycan-chemokine interactions with a probe to alter leukocyte recruitment and inflammation in vivo

    Get PDF
    In vivo leukocyte recruitment is not fully understood and may result from interactions of chemokines with glycosaminoglycans/GAGs. We previously showed that chlorite-oxidized oxyamylose/COAM binds the neutrophil chemokine GCP-2/CXCL6. Here, mouse chemokine binding by COAM was studied systematically and binding affinities of chemokines to COAM versus GAGs were compared. COAM and heparan sulphate bound the mouse CXC chemokines KC/CXCL1, MIP-2/CXCL2, IP-10/CXCL10 and I-TAC/CXCL11 and the CC chemokine RANTES/CCL5 with affinities in the nanomolar range, whereas no binding interactions were observed for mouse MCP-1/CCL2, MIP-1α/CCL3 and MIP-1β/CCL4. The affinities of COAM-interacting chemokines were similar to or higher than those observed for heparan sulphate. Although COAM did not display chemotactic activity by itself, its co-administration with mouse GCP-2/CXCL6 and MIP-2/CXCL2 or its binding of endogenous chemokines resulted in fast and cooperative peritoneal neutrophil recruitment and in extravasation into the cremaster muscle in vivo. These local GAG mimetic features by COAM within tissues superseded systemic effects and were sufficient and applicable to reduce LPS-induced liver-specific neutrophil recruitment and activation. COAM mimics glycosaminoglycans and is a nontoxic probe for the study of leukocyte recruitment and inflammation in vivo

    Matrix Metalloproteinase-Induced Epithelial-Mesenchymal Transition in Breast Cancer

    Get PDF
    Matrix metalloproteinases (MMPs) degrade and modify the extracellular matrix (ECM) as well as cell-ECM and cell-cell contacts, facilitating detachment of epithelial cells from the surrounding tissue. MMPs play key functions in embryonic development and mammary gland branching morphogenesis, but they are also upregulated in breast cancer, where they stimulate tumorigenesis, cancer cell invasion and metastasis. MMPs have been investigated as potential targets for cancer therapy, but clinical trials using broad-spectrum MMP inhibitors yielded disappointing results, due in part to lack of specificity toward individual MMPs and specific stages of tumor development. Epithelial-mesenchymal transition (EMT) is a developmental process in which epithelial cells take on the characteristics of invasive mesenchymal cells, and activation of EMT has been implicated in tumor progression. Recent findings have implicated MMPs as promoters and mediators of developmental and pathogenic EMT processes in the breast. In this review, we will summarize recent studies showing how MMPs activate EMT in mammary gland development and in breast cancer, and how MMPs mediate breast cancer cell motility, invasion, and EMT-driven breast cancer progression. We also suggest approaches to inhibit these MMP-mediated malignant processes for therapeutic benefit

    Genome of the facultative scuticociliatosis pathogen Pseudocohnilembus persalinus provides insight into its virulence through horizontal gene transfer

    Get PDF
    This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ The attached file is the published version of the article

    A precise bathymetric map of the world’s deepest seafloor, Challenger Deep in the Mariana Trench

    Get PDF
    Data from three bathymetric surveys by R/V Kairei using a 12-kHz multibeam echosounder and differential GPS were used to create an improved topographic model of the Challenger Deep in the southwestern part of the Mariana Trench, which is known as the deepest seafloor in the world. The strike of most of the elongated structures related to plate bending accompanied by subduction of the Pacific plate is N70°E and is not parallel to the trench axis. The bending-related structures were formed by reactivation of seafloor spreading fabric. Challenger Deep consists of three en echelon depressions along the trench axis, each of which is 6-10 km long, about 2 km wide, and deeper than 10,850 m. The eastern depression is the deepest, with a depth of 10,920 ± 5 m
    corecore