1,178 research outputs found

    Endocytosis of dextran and silan-coated magnetite nanoparticles and the effect of intracellular hyperthermia on human mammary carcinoma cells in vitro

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    To obtain more evidence for intracellular magnetic fluid hyperthermia (MFH), endocytosis and hyperthermia efficacy of silan and dextran magnetite was investigated. Differential endocytosis was observed in dependence of nanoparticle and cell type. Clonogenic survival was 3-fold lower after MFH versus waterbath hyperthermia. The selective \u27remote inactivation\u27 of cancer cells by an AC magnetic field has been demonstrated in vitro

    Neurogenesis from Sox2 expressing cells in the adult cerebellar cortex

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    We identified a rare undifferentiated cell population that is intermingled with the Bergmann glia of the adult murine cerebellar cortex, expresses the stem cell markers Sox2 and Nestin, and lacks markers of glial or neuronal differentiation. Interestingly, such Sox2(+) S100(-) cells of the adult cerebellum expanded after adequate physiological stimuli in mice (exercise), and Sox2(+) precursors acquired positivity for the neuronal marker NeuN over time and integrated into cellular networks. In human patients, SOX2(+) S100(-) cells similarly increased in number after relevant pathological insults (infarcts), suggesting a similar expansion of cells that lack terminal glial differentiation

    Relaxation and edge reconstruction in integer quantum Hall systems

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    The interplay between the confinement potential and electron-electron interactions causes reconstructions of Quantum Hall edges. We study the consequences of this edge reconstruction for the relaxation of hot electrons injected into integer quantum Hall edge states. In translationally invariant edges, the relaxation of hot electrons is governed by three-body collisions which are sensitive to the electron dispersion and thus to reconstruction effects. We show that the relaxation rates are significantly altered in different reconstruction scenarios.Comment: 8 pages, 3 figure

    Critical Casimir effect in films for generic non-symmetry-breaking boundary conditions

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    Systems described by an O(n) symmetrical ϕ4\phi^4 Hamiltonian are considered in a dd-dimensional film geometry at their bulk critical points. A detailed renormalization-group (RG) study of the critical Casimir forces induced between the film's boundary planes by thermal fluctuations is presented for the case where the O(n) symmetry remains unbroken by the surfaces. The boundary planes are assumed to cause short-ranged disturbances of the interactions that can be modelled by standard surface contributions ϕ2\propto \bm{\phi}^2 corresponding to subcritical or critical enhancement of the surface interactions. This translates into mesoscopic boundary conditions of the generic symmetry-preserving Robin type nϕ=c˚jϕ\partial_n\bm{\phi}=\mathring{c}_j\bm{\phi}. RG-improved perturbation theory and Abel-Plana techniques are used to compute the LL-dependent part fresf_{\mathrm{res}} of the reduced excess free energy per film area AA\to\infty to two-loop order. When d<4d<4, it takes the scaling form fresD(c1LΦ/ν,c2LΦ/ν)/Ld1f_{\mathrm{res}}\approx D(c_1L^{\Phi/\nu},c_2L^{\Phi/\nu})/L^{d-1} as LL\to\infty, where cic_i are scaling fields associated with the surface-enhancement variables c˚i\mathring{c}_i, while Φ\Phi is a standard surface crossover exponent. The scaling function D(c1,c2)D(\mathsf{c}_1,\mathsf{c}_2) and its analogue D(c1,c2)\mathcal{D}(\mathsf{c}_1,\mathsf{c}_2) for the Casimir force are determined via expansion in ϵ=4d\epsilon=4-d and extrapolated to d=3d=3 dimensions. In the special case c1=c2=0\mathsf{c}_1=\mathsf{c}_2=0, the expansion becomes fractional. Consistency with the known fractional expansions of D(0,0) and D(0,0)\mathcal{D}(0,0) to order ϵ3/2\epsilon^{3/2} is achieved by appropriate reorganisation of RG-improved perturbation theory. For appropriate choices of c1c_1 and c2c_2, the Casimir forces can have either sign. Furthermore, crossovers from attraction to repulsion and vice versa may occur as LL increases.Comment: Latex source file, 40 pages, 9 figure

    The Threat of Capital Drain: A Rationale for Public Banks?

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    This paper yields a rationale for why subsidized public banks may be desirable from a regional perspective in a financially integrated economy. We present a model with credit rationing and heterogeneous regions in which public banks prevent a capital drain from poorer to richer regions by subsidizing local depositors, for example, through a public guarantee. Under some conditions, cooperative banks can perform the same function without any subsidization; however, they may be crowded out by public banks. We also discuss the impact of the political structure on the emergence of public banks in a political-economy setting and the role of interregional mobility

    Presentation of a new magnetic field therapy system for the treatment of human solid tumors with magnetic fluid hyperthermia

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    Magnetic fluid hyperthermia (MFH) selectively heats up tissue by coupling alternating current (AC) magnetic fields to targeted magnetic fluids, so that boundaries of different conductive tissues do not interfere with power absorption. In this paper, a new AC magnetic field therapy system for clinical application of MFH is described. With optimized magnetic nanoparticle preparations it will be used for target-specific glioblastoma and prostate carcinoma therapy

    Super Resolution Fluorescence Microscopy and Tracking of Bacterial Flotillin (Reggie) Paralogs Provide Evidence for Defined-Sized Protein Microdomains within the Bacterial Membrane but Absence of Clusters Containing Detergent-Resistant Proteins

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    Biological membranes have been proposed to contain microdomains of a specific lipid composition, in which distinct groups of proteins are clustered. Flotillin-like proteins are conserved between pro—and eukaryotes, play an important function in several eukaryotic and bacterial cells, and define in vertebrates a type of so-called detergent-resistant microdomains. Using STED microscopy, we show that two bacterial flotillins, FloA and FloT, form defined assemblies with an average diameter of 85 to 110 nm in the model bacterium Bacillus subtilis. Interestingly, flotillin microdomains are of similar size in eukaryotic cells. The soluble domains of FloA form higher order oligomers of up to several hundred kDa in vitro, showing that like eukaryotic flotillins, bacterial assemblies are based in part on their ability to self-oligomerize. However, B. subtilis paralogs show significantly different diffusion rates, and consequently do not colocalize into a common microdomain. Dual colour time lapse experiments of flotillins together with other detergent-resistant proteins in bacteria show that proteins colocalize for no longer than a few hundred milliseconds, and do not move together. Our data reveal that the bacterial membrane contains defined-sized protein domains rather than functional microdomains dependent on flotillins. Based on their distinct dynamics, FloA and FloT confer spatially distinguishable activities, but do not serve as molecular scaffolds

    Clinicopathologic and molecular analysis of embryonal rhabdomyosarcoma of the genitourinary tract: evidence for a distinct DICER1-associated subgroup.

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    Embryonal rhabdomyosarcoma (ERMS) of the uterus has recently been shown to frequently harbor DICER1 mutations. Interestingly, only rare cases of extrauterine DICER1-associated ERMS, mostly located in the genitourinary tract, have been reported to date. Our goal was to study clinicopathologic and molecular profiles of DICER1-mutant (DICER1-mut) and DICER1-wild type (DICER1-wt) ERMS in a cohort of genitourinary tumors. We collected a cohort of 17 ERMS including nine uterine (four uterine corpus and five cervix), one vaginal, and seven urinary tract tumors. DNA sequencing revealed mutations of DICER1 in 9/9 uterine ERMS. All other ERMS of our cohort were DICER1-wt. The median age at diagnosis of patients with DICER1-mut and DICER1-wt ERMS was 36 years and 5 years, respectively. Limited follow-up data (available for 15/17 patients) suggested that DICER1-mut ERMS might show a less aggressive clinical course than DICER1-wt ERMS. Histological features only observed in DICER1-mut ERMS were cartilaginous nodules (6/9 DICER1-mut ERMS), in one case accompanied by foci of ossification. Recurrent mutations identified in both DICER1-mut and DICER1-wt ERMS affected KRAS, NRAS, and TP53. Copy number analysis revealed similar structural variations with frequent gains on chromosomes 2, 3, and 8, independent of DICER1 mutation status. Unsupervised hierarchical clustering of array-based whole-genome DNA methylation data of our study cohort together with an extended methylation data set including different RMS subtypes from genitourinary and extra-genitourinary locations (n = 102), revealed a distinct cluster for DICER1-mut ERMS. Such tumors clearly segregated from the clusters of DICER1-wt ERMS, alveolar RMS, and MYOD1-mutant spindle cell and sclerosing RMS. Only one tumor, previously diagnosed as ERMS arising in the maxilla of a 6-year-old boy clustered with DICER1-mut ERMS of the uterus. Subsequent sequencing analysis identified two DICER1 mutations in the latter case. Our results suggest that DICER1-mut ERMS might qualify as a distinct subtype in future classifications of RMS

    Endocytosis of dextran and silan-coated magnetite nanoparticles and the effect of intracellular hyperthermia on human mammary carcinoma cells in vitro

    Get PDF
    To obtain more evidence for intracellular magnetic fluid hyperthermia (MFH), endocytosis and hyperthermia efficacy of silan and dextran magnetite was investigated. Differential endocytosis was observed in dependence of nanoparticle and cell type. Clonogenic survival was 3-fold lower after MFH versus waterbath hyperthermia. The selective 'remote inactivation' of cancer cells by an AC magnetic field has been demonstrated in vitro

    Development of a GEM-TPC prototype

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    The use of GEM foils for the amplification stage of a TPC instead of a con- ventional MWPC allows one to bypass the necessity of gating, as the backdrift is suppressed thanks to the asymmetric field configuration. This way, a novel continuously running TPC, which represents one option for the PANDA central tracker, can be realized. A medium sized prototype with a diameter of 300 mm and a length of 600 mm will be tested inside the FOPI spectrometer at GSI using a carbon or lithium beam at intermediate energies (E = 1-3AGeV). This detector test under realistic experimental conditions should allow us to verify the spatial resolution for single tracks and the reconstruction capability for displaced vertexes. A series of physics measurement implying pion beams is scheduled with the FOPI spectrometer together with the GEM-TPC as well.Comment: 5 pages, 4 figures, Proceedings for 11th ICATTP conference in como (italy
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