3,502 research outputs found

    On the efficient numerical solution of lattice systems with low-order couplings

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    We apply the Quasi Monte Carlo (QMC) and recursive numerical integration methods to evaluate the Euclidean, discretized time path-integral for the quantum mechanical anharmonic oscillator and a topological quantum mechanical rotor model. For the anharmonic oscillator both methods outperform standard Markov Chain Monte Carlo methods and show a significantly improved error scaling. For the quantum mechanical rotor we could, however, not find a successful way employing QMC. On the other hand, the recursive numerical integration method works extremely well for this model and shows an at least exponentially fast error scaling

    Tumor cell-selective apoptosis induction through targeting of KV10.1 via bifunctional TRAIL antibody

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    <p>Abstract</p> <p>Background</p> <p>The search for strategies to target ion channels for therapeutic applications has become of increasing interest. Especially, the potassium channel K<sub>V</sub>10.1 (Ether-á-go-go) is attractive as target since this surface protein is virtually not detected in normal tissue outside the central nervous system, but is expressed in approximately 70% of tumors from different origins.</p> <p>Methods</p> <p>We designed a single-chain antibody against an extracellular region of K<sub>V</sub>10.1 (scFv62) and fused it to the human soluble TRAIL. The K<sub>V</sub>10.1-specific scFv62 antibody -TRAIL fusion protein was expressed in CHO-K1 cells, purified by chromatography and tested for biological activity.</p> <p>Results</p> <p>Prostate cancer cells, either positive or negative for K<sub>V</sub>10.1 were treated with the purified construct. After sensitization with cytotoxic drugs, scFv62-TRAIL induced apoptosis only in K<sub>V</sub>10.1-positive cancer cells, but not in non-tumor cells, nor in tumor cells lacking K<sub>V</sub>10.1 expression. In co-cultures with K<sub>V</sub>10.1-positive cancer cells the fusion protein also induced apoptosis in bystander K<sub>V</sub>10.1-negative cancer cells, while normal prostate epithelial cells were not affected when present as bystander.</p> <p>Conclusions</p> <p>K<sub>V</sub>10.1 represents a novel therapeutic target for cancer. We could design a strategy that selectively kills tumor cells based on a K<sub>V</sub>10.1-specific antibody.</p

    Optical Response of Grating-Coupler-Induced Intersubband Resonances: The Role of Wood's Anomalies

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    Grating-coupler-induced collective intersubband transitions in a quasi-two-dimensional electron system are investigated both experimentally and theoretically. Far-infrared transmission experiments are performed on samples containing a quasi-two-dimensional electron gas quantum-confined in a parabolic quantum well. For rectangular shaped grating couplers of different periods we observe a strong dependence of the transmission line shape and peak height on the period of the grating, i.e. on the wave vector transfer from the diffracted beams to the collective intersubband resonance. It is shown that the line shape transforms with increasing grating period from a Lorentzian into a strongly asymmetric line shape. Theoretically, we treat the problem by using the transfer-matrix method of local optics and apply the modal-expansion method to calculate the influence of the grating. The optically uniaxial quasi-two-dimensional electron gas is described in the long-wavelength limit of the random-phase approximation by a local dielectric tensor, which includes size quantization effects. Our theory reproduces excellently the experimental line shapes. The deformation of the transmission line shapes we explain by the occurrence of both types of Wood's anomalies.Comment: 28 pages, 7 figures. Physical Review B , in pres

    Lunar ephemeris selenographic coordinates of the earth and sun for 1975 and 1976

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    Ephemeris data are presented for 1975 and 1976 to provide a time history of lunar coordinates and related geometric information. A Manned Spacecraft Center modification of the Jet Propulsion Laboratory ephemeris tape was used to calculate and plot coordinates of the earth, moon, and sun. The ephemeris is referenced to the mean vernal equinox at the nearest beginning of a Besselian year. Therefore the reference equinox changes from one year to the next between 30 June and 1 July. The apparent discontinuity in the data is not noticeable in the graphical presentation, but can be observed in the digital output. The mean equator of epoch is used in all cases

    The role of toll-like receptors (TLRs) in bacteria-induced maturation of murine dendritic cells (DCs) - Peptidoglycan and lipoteichoic acid are inducers of DC maturation and require TLR2

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    Toll-like receptors (TLRs) have been found to be key elements in pathogen recognition by the host immune system. Dendritic cells (DCs) are crucial for both innate immune responses and initiation of acquired immunity. Here we focus on the potential involvement of TLR ligand interaction in DC maturation. TLR2 knockout mice and mice carrying a TLR4 mutation (C3H/HeJ) were investigated for DC maturation induced by peptidoglycan (PGN), lipopolysaccharide (LPS), or lipoteichoic acids (LTAs). All stimuli induced maturation of murine bone marrow-derived DCs in control mice. TLR2− /− mice lacked maturation upon stimulation with PGN, as assessed by expression of major histocompatibility complex class II, CD86, cytokine, and chemokine production, fluorescein isothiocyanate-dextran uptake, and mixed lymphocyte reactions, while being completely responsive to LPS. A similar lack of maturation was observed in C3H/HeJ mice upon stimulation with LPS. DC maturation induced by LTAs from two different types of bacteria was severely impaired in TLR2− /−, whereas C3H/HeJ mice responded to LTAs in a manner similar to wild-type mice. We demonstrate that DC maturation is induced by stimuli from Gram-positive microorganisms, such as PGN and LTA, with similar efficiency as by LPS. Finally, we provide evidence that TLR2 and TLR4 interaction with the appropriate ligand is essential for bacteria-induced maturation of DCs

    Hybridization of electron subbands in a double quantum well at quantizing magnetic field

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    We employ magnetocapacitance and far-infrared spectroscopy techniques to study the spectrum of the double-layer electron system in a parabolic quantum well with a narrow tunnel barrier in the centre. For gate-bias-controlled asymmetric electron density distributions in this soft two-subband system we observe both individual subband gaps and double layer gaps at integer filling factor ν\nu. The bilayer gaps are shown to be either trivial common for two subbands or caused by hybridization of electron subbands in magnetic field. We describe the observed hybrid gaps at ν=1\nu=1 and ν=2\nu=2 within a simple model for the modified bilayer spectrum.Comment: REVTeX, 24 pages, 9 figures included. Submitted to Phys. Rev.

    Tenure and Due Process

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    The legal significance of tenure is reviewed in this article as it relates to the new and developing laws of due process. The authors suggest that expectancy of re-employment may become a new form of property right
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