Influence of Magnetic Field on Electric Charge Transport in Holomiun Thin Films at Low Temperatures

Holmium thin films were prepared by evaporation in ultrahigh vacuum (UHV) and high precision electrical resistance measurements were performed on them as well as on holomium bulk sample in the wide temperature range from 4,2 K up to the room temperature. Electric charge transport is profoundly influenced by the magnetic structure at low temperatures and a "knee-like" resistance anomaly was observed near the transportation from paramagnetic state to basal-plane spiral structure in bulk with the Neel temperature TN=128,9 K and below ~ 122 K in thin Ho films in a thickness range from 98 nm to 215 nm. Unexpected resistance minimum at ~ 9 K and a slope´s charge of the R vs. T curve near ~ 170 K was observed in 215 nm thin film. Application of magnetic field parallel to the substrate and thin film plane for temperatures below ~ 150 K caused the decrease of resistence value with increasing magnetic flux density. Increasing suppression of the TN value up to ~ 5 K with increasing flux density value up to 5 T was observed in Ho films. <br /

Properties and structure of (Tl(0.5)Pb(0.5))Sr(2)(Ca(1-x)Nd(x))Cu(2)O(z)(Tl-1212) superconductors

International audienceBulk material of Nd-doped Tl-1212 superconductors was prepared via a two-step procedure based on a wet chemical method to prepare precursor material followed by heat-treatment at 895 degrees C for 10 h. The samples with Nd stoichiometry of x = 0.05, 0.1, 0.15, 0.20 0.25 and 0.30 were characterized by XRD, electron microscopy and by resistance measurements. Oxygen stoichiometry of the specimens was analyzed. Lattice parameters were derived from x-ray diffraction and neutron diffraction measurements. The increase of the a-axis and the decrease of the c-axis as a function of the Nd content are discussed

Microstructure and Magnetic Properties of La-Ca-Sr-Mn-O Perovskite Ceramics

$La_{0.67}Ca_{0.33-x}Sr_{x}MnO_{3}$ (x=0.33; 0.03; 0) (LCSM) perovskite magnetocaloric ceramics were prepared by solid state synthesis in air and sintering at 1520°. The phase composition was checked by x-ray powder diffraction. Microstructure analyses were done by scanning electron microscopy. The influence of high pressure oxygenation on magnetisation behaviour is shown

Immunopathogenesis of HPV-Associated Cancers and Prospects for Immunotherapy

Human papillomavirus (HPV) infection is a causative factor for various cancers of the anogenital region and oropharynx, and is supposed to play an important cofactor role for skin carcinogenesis. Evasion from immunosurveillance favors viral persistence. However, there is evidence that the mere presence of oncogenic HPV is not sufficient for malignant progression and that additional tumor-promoting steps are required. Recent studies have demonstrated that HPV-transformed cells actively promote chronic stromal inflammation and conspire with cells in the local microenvironment to promote carcinogenesis. This review highlights the complex interplay between HPV-infected cells and the local immune microenvironment during oncogenic HPV infection, persistence, and malignant progression, and discusses new prospects for diagnosis and immunotherapy of HPV-associated cancers