Susceptibility functions for slow relaxation processes in supercooled liquids and the search for universal relaxation patterns

In order to describe the slow response of a glass former we discuss some distribution of correlation times, e.g., the generalized gamma distribution (GG) and an extension thereof (GGE), the latter allowing to reproduce a simple peak susceptibility such as of Cole-Davidson type as well as a susceptibility exhibiting an additional high frequency power law contribution (excess wing). Applying the GGE distribution to the dielectric spectra of glass formers exhibiting no beta-process peak (glycerol, propylene carbonate and picoline) we are able to reproduce the salient features of the slow response (1e-6 Hz - 1e9 Hz). A line shape analysis is carried out either in the time or frequency domain and in both cases an excess wing can be identified. The latter evolves in a universal way while cooling and shows up for correlation times tau_alpha > 1e-8 s. It appears that its first emergence marks the break down of the high temperature scenario of mode coupling theory. - In order to describe a glass former exhibiting a beta-process peak we have introduced a distribution function which is compatible with assuming a thermally activated process in contrast to some commonly used fit functions. Together with the GGE distribution this function allows in the frame of the Williams-Watts approach to completely interpolate the spectra, e.g. of fluoro aniline (1e-6 Hz - 1e9 Hz). The parameters obtained indicate an emergence of both the excess wing and the beta-process again at tau_alpha > 1e-8s.Comment: 22 pages, 12 figure

Myśli intruzyjne w populacji zdrowej – norma czy fenomen?

Intrusive Thoughts in a Healthy Population – a Norm or an ExceptionIntrusive thoughts, until recently, were considered to be a phenomenon present only in mental disorders. Beginning with the pioneering research by Stanley Rachman and Padmal de Silva in 1978, researchers have turned attention to the commonness of intrusions among healthy persons. Article takes up the issue of intrusive thoughts in a normal, healthy population. The occurrence and characteristic features of intrusive thoughts are analysed, as well as factors that can affect their appearance and severity. Differences between intrusions in healthy persons and those with mental disorders are also considered

Evidence of secondary relaxations in the dielectric spectra of ionic liquids

We investigated the dynamics of a series of room temperature ionic liquids based on the same 1-butyl-3-methyl imidazolium cation and different anions by means of broadband dielectric spectroscopy covering 15 decades in frequency (10^(-6)-10^9 Hz), and in the temperature range from 400 K down to 35 K. An ionic conductivity is observed above the glass transition temperature T_{g} with a relaxation in the electric modulus representation. Below T_{g}, two relaxation processes appear, with the same features as the secondary relaxations typically observed in molecular glasses. The activation energy of the secondary processes and their dependence on the anion are different. The slower process shows the characteristics of an intrinsic Johari-Goldstein relaxation, in particular an activation energy E_{beta}=24k_{B}T_{g} is found, as observed in molecular glasses.Comment: Major revision, submitted to Phys. Rev. Let

A pluri- és multipotencia határán: a ganglionléc őssejtjei

Absztrakt A ganglionléc a gerinces embriókban megjelenő átmeneti, multipotens, vándorló sejtpopuláció, amiből a perifériás idegrendszer idegi és gliális elemeitől kezdve a craniofacialis terület ectomesenchymalis származékain vagy a bőr pigmentsejtjein át számos struktúra származtatható. Érdekes módon a ganglionléc-eredetű őssejtek nem csak az embrionális ganglionlécben vannak jelen, hanem megtalálhatók az általuk betelepített embrionális és felnőttkori szövetekben is. Ezek a posztmigrációs őssejtek – legalábbis részlegesen – tükrözik elődeik multipotenciáját. Ráadásul az olyan ganglionléc-eredetű, terminálisan differenciálódott sejtek, mint például a Schwann-sejtek és a melanocyták, bármikor képesek őssejtszerű progenitorokká dedifferenciálódni. Az összefoglaló tanulmányban a szerzők bemutatják, hogy mit tudunk jelenleg ezekről a különleges plaszticitású őssejtekről és milyen potenciális alkalmazási lehetőségek merülnek fel velük kapcsolatban a regeneratív orvoslás területén. Orv. Hetil., 2015, 156(42), 1683–1694

Der Einfluss der Muskelrelaxierung bei Intubation auf die Herzratenvariabilität bei Kindern: eine prospektive randomisierte Studie

In der vorliegenden prospektiven, randomisierten klinischen Studie wurde der Einfluss der Muskelrelaxierung bei Intubation auf die Herzratenvariabilität bei 34 Kindern untersucht. Eine Gruppe wurde hierbei nach Gabe des Muskelrelaxanz (MR) Mivacurium intubiert. Die andere Gruppe ohne Gabe eines Muskelrelaxanz (NoMR). Bei beiden Gruppen wurde eine HRV-Messung durchgeführt. Berechnet wurde die LF, die HF und die Ratio LF/HF. In der MR-Gruppe war die LF und die Ratio LF/HF gegenüber der NoMR-Gruppe erhöht. Die mit der HRV erfasste Stessreaktion ist ohne Gabe von Muskelrelaxanzien größer

Establishment and Characterization of a Brca1 −/−, p53 −/− Mouse Mammary Tumor Cell Line

Breast cancer is the most commonly occurring cancer in women and the second most common cancer overall. By the age of 80, the estimated risk for breast cancer for women with germline BRCA1 or BRCA2 mutations is around 80%. Genetically engineered BRCA1-deficient mouse models offer a unique opportunity to study the pathogenesis and therapy of triple negative breast cancer. Here we present a newly established Brca1−/−, p53−/− mouse mammary tumor cell line, designated as CST. CST shows prominent features of BRCA1-mutated triple-negative breast cancers including increased motility, high proliferation rate, genome instability and sensitivity to platinum chemotherapy and PARP inhibitors (olaparib, veliparib, rucaparib and talazoparib). Genomic instability of CST cells was confirmed by whole genome sequencing, which also revealed the presence of COSMIC (Catalogue of Somatic Mutations in Cancer) mutation signatures 3 and 8 associated with homologous recombination (HR) deficiency. In vitro sensitivity of CST cells was tested against 11 chemotherapy agents. Tumors derived from orthotopically injected CST-mCherry cells in FVB-GFP mice showed sensitivity to cisplatin, providing a new model to study the cooperation of BRCA1-KO, mCherry-positive tumor cells and the GFP-expressing stromal compartment in therapy resistance and metastasis formation. In summary, we have established CST cells as a new model recapitulating major characteristics of BRCA1-negative breast cancers

Mechanical and dielectric relaxation spectra in seven highly viscous glass formers

Published dielectric and shear data of six molecular glass formers and one polymer are evaluated in terms of a spectrum of thermally activated processes, with the same barrier density for the retardation spectrum of shear and dielectrics. The viscosity, an independent parameter of the fit, seems to be related to the high-barrier cutoff time of the dielectric signal, in accordance with the idea of a renewal of the relaxing entities after this critical time. In the five cases where one can fit accurately, the temperature dependence of the high-barrier cutoff follows the shoving model. The Johari-Goldstein peaks, seen in four of our seven cases, are describable in terms of gaussians in the barrier density, superimposed on the high-frequency tail of the $\alpha$-process. Dielectric and shear measurements of the same substance find the same peak positions and widths of these gaussians, but in general a different weight.Comment: Contribution to the Ngai Fest issue of J. Non-Cryst. Solids; 8 pages, 8 figures, 30 reference

Regulation of mouse microglia activation and effector functions by bone marrow-derived mesenchymal stem cells

Mesenchymal stem or stromal cells (MSCs) are rare multipotent cells with potent regenerative and immunomodulatory properties. Microglial cells are specialized tissue macrophages of the central nervous system (CNS) that continuously survey their environment with highly motile extensions. Recently several studies have shown that MSCs are capable of reprogramming microglia into an “M2-like” phenotype characterized by increased phagocytic activity and upregulated expression of anti- inflammatory mediators in vitro. However, the precise polarization states of microglia in the presence of MSCs under physiological or under inflammatory conditions remain largely unknown. In this study, we found that MSCs induce a mixed microglia phenotype defined as Arg-1-high, CD86-high, CD206-high, IL-10-high, PGE2-high, MCP-1/CCL2-high, IL-1β- moderate, NALP-3-low, and TNF-α-low cells. These MSC-elicited microglial cells have high phagocytic activity and antigen-presenting ability. Lipopolysaccharide (LPS) is able to shape this microglia phenotype quantitatively, but not qualitatively in the presence of MSCs. This unique polarization state resembles a novel regulatory microglia phenotype, which might contribute to the resolution of inflammation and to tissue repair in the CNS