254 results match your criteria: "Universitt[Affiliation]"

We present a fiber-coupled diamond-based single photon system. Single nanodiamonds containing nitrogen vacancy defect centers are deposited on a tapered fiber of 273 nanometer in diameter providing a record-high number of 689,000 single photons per second from a defect center in a single-mode fiber. The system can be cooled to cryogenic temperatures and coupled evanescently to other nanophotonic structures, such as microresonators.

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Background And Objective: Weight gain is a common problem of treatment with atypical antipsychotics. However, the dimension of body weight change differs interindividually, and various genetic factors are considered to be associated with this effect. Peroxisome proliferator-activated receptor gamma (PPARG) Pro12Ala polymorphism and its reported relationship to type 2 diabetes susceptibility and body mass accumulation prompted us to investigate the impact of this single nucleotide polymorphism (SNP) on antipsychotic-induced changes of body weight and body mass index (BMI) in a naturalistic study design.

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Vortex solitons at the boundaries of photonic lattices.

Opt Express

December 2011

Institut für Angewandte Physik and Center for Nonlinear Science (CeNoS), Westfälische Wilhelms-Universitt Münster, Münster, Germany.

Using numerical analysis we demonstrate the existence of vortex solitons at the edge and in the corners of two-dimensional triangular photonic lattice. We develop a concise picture of their behavior in both single-propagating and counterpropagating beam geometries. In the single-beam geometry, we observe stable surface vortex solitons for long propagation distances only in the form of discrete six-lobe solutions at the edge of the photonic lattice.

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Load theory predicts that concurrent cognitive load impairs selective attention. For visual stimuli, it has been shown that this impairment can be selective: Distraction was specifically increased when the stimulus material used in the cognitive load task matches that of the selective attention task. Here, we report four experiments that demonstrate such selective load effects for auditory selective attention.

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The second window of anaesthetic-induced preconditioning (APC) is afforded by the interplay of multiple signalling pathways, whereas a similar protective response is mediated by peroxisome-proliferator-activated receptor γ (PPARγ) agonists. However, a possible role of this nuclear receptor during APC has not been studied to date. We investigated the hypothesis that the second window of APC is mediated by the activation of PPARγ.

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Subwavelength broadband splitters and switches for femtosecond plasmonic signals.

Opt Express

May 2010

1 Institut fr Physikalische und Theoretische Chemie, Universitt Wrzburg, Am Hubland, 97074, Wrzburg, Germany.

Numerical simulations and an analytic approach based on transmission line theory are used to design splitters for nano-plasmonic signal processing that allow to arbitrarily adjust the ratio of transmission from an input into two different output arms. By adjusting the geometrical parameters of the structure, either a high bandwidth or a sharp transmission resonance is obtained. Switching between the two arms can be achieved by modulating the effective refractive index of the waveguide.

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Aging in men is associated with a gradual and progressive decline in serum total testosterone concentrations as a result of primary testicular and secondary hypothalamic-pituitary dysfunction. Androgen secretion does not cease, it gradually decreases but usually continues at some level. A diagnosis of hypogonadism should rely on both symptoms and laboratory tests.

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In a convergent modular synthesis, a very efficient pathway to shape-persistent molecular spoked wheels has been developed and applied according to the covalent-template concept. The structurally defined two-dimensional (2D) oligo(phenylene-ethynylene-butadiynylene)s (OPEBs) presented here are about 8 nm sized hydrocarbons of high symmetry. 48 alkyl chains attached to the molecular plane (hexyl and hexadecyl, respectively) guarantee a high solubility of the compounds.

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Colloid dispersion on the pore scale.

Water Res

February 2010

Institute of Hydrochemistry, Technische Universitt Mnchen, Marchioninistr. 17, D-81377 Munich, Germany.

Dispersion describes the spreading of a tracer or contaminant in an aquifer. Detailed knowledge of dispersion is the key to successful risk assessment in case of groundwater pollution or groundwater protection. The dispersion of colloids on the pore scale is controlled by flow velocity, ionic strength, colloid size, colloid concentration, and colloid-matrix interactions.

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Combining dynamic heteroleptic complex formation with constitutional dynamic synthesis: a facile way to M3LL' cage assemblies.

Inorg Chem

July 2009

Center for Micro- and Nanochemistry and Engineering, Organische Chemie I, Universitt Siegen, Adolf-Reichwein-Strasse, 57068 Siegen, Germany.

The quantitative preparation of heteroleptic copper(I) complexes arising from a combination of 2,9-diarylphenanthrolines and iminopyridines (Schiff bases) is described. This strategy was applied to construct mono- and binuclear complexes but equally a discrete three-dimensional M(3)LL' cage. By means of a constitutional dynamic synthesis, the heteroleptic aggregates were equally prepared from four-component mixtures using the copper(I) center as a catalyst for the in situ generation of the iminopyridine ligands.

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Cancer stem cells and radiotherapy.

Int J Radiat Biol

May 2009

Department of Radiation Oncology, Medical Faculty and University Hospital Carl Gustav Carus, Technische Universitt Dresden, Germany.

Purpose: The present work summarises the history and current status of research into the importance of cancer stem cells for radiobiological research and for clinical radiation oncology. An effort is made to differentiate clonogenicity from stemness of cancer cells.

Conclusion: In radiooncology, cancer stem cells have been an important research field for five decades.

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Supercritical fluid reactive deposition was used for the deposition of highly dispersed platinum nanoparticles with controllable metal content and particle size distribution on beta-cyclodextrin. The average particle size and size distribution were steered by the precursor reduction conditions, resulting in particle preparations <20, <100, and >100 nm as characterized by transmission electron microscopy and scanning electron microscopy (SEM). These particle preparations of different size distributions were used to address the question as to whether metallic platinum particles are able to invade cells of the gastrointestinal tract as exemplified for the human colon carcinoma cell line HT29 and thus affect the cellular redox status and DNA integrity.

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We present a theoretical study of the structural and optical properties of tripeptide-silver cluster hybrid systems which shows that silver clusters induce significant absorption enhancement in the spectral region between 225 and 350 nm with respect to the pure peptide. This allows the use of clusters as chromophores for absorption enhancement of peptides and proteins and offers a potential for different applications in biosensing. Furthermore, we demonstrate that cluster binding can change the conformational preference for the secondary structure type leading possibly to new functional properties.

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[Influence of cyclops syndrome after anterior cruciate ligament reconstruction on the functional outcome].

Sportverletz Sportschaden

December 2008

Abteilung für Unfallchirurgie, Plastische und Wiederherstellungschirurgie, Universitätsmedizin Göttingen, Georg-August-Universitt, Robert-Koch-Str. 40, 37099 Gçttingen.

Background: A review of recent reports concerning the functional outcome after treatment for Cyclops syndrome can produce contradictory results. Therefore, the purpose of this study was to evaluate the functional outcome of our patients treated for Cyclops syndrome after anterior cruciate ligament reconstruction.

Methods: Between 1998 and 2006 ten patients were followed for the occurrence of a Cyclops syndrome.

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Structure of thiol self-assembled monolayers commensurate with the GaAs (001) surface.

Langmuir

December 2008

Department of Electrical and Computer Engineering, Centre of Excellence for Information Engineering, Universitt de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada.

Observed properties of thiol self-assembled monolayers (SAMs) on GaAs (001) surfaces can be explained by the presence of surface reconstructions, but their exact form is generally unknown. We propose a new approach to modeling the SAM-surface interface based on using alkanethiol dense packing structures as a starting point and adjusting the surface reconstruction to accommodate them. Obtained in such a way, model SAMs adsorb along the trenches in the [110] direction and exhibit a 19 degrees tilt and +/- 45 degrees twist angles, in agreement with available experimental data.

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Recent reports on intense-field pump-probe experiments for high-order harmonic generation (HHG) from coherently rotating linear molecules have revealed remarkable characteristic effects of the simultaneous variation of the polarization geometry and the time delay on the high-order harmonic signals. We analyze the effects and give a unified theoretical account of the experimental observations. Furthermore, characteristic behavior at critical polarization angles are found that can help to identify the molecular orbital symmetry in connection with the problem of molecular imaging from the HHG data.

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The mushroom bodies of insects are viewed as key neuropils for sensory integration and perhaps learning and memory. In Hymenoptera, particularly ants, the calyx of the mushroom bodies is divided into two main regions, the lip and the collar. Although most ants are highly dependent on olfaction and have enlarged calyces comprised mostly of lip, some ant groups are also highly visual and have well-developed collars.

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In order to estimate the impact of an innovation on a segment of the health care system under certain assumptions such as different possible regulatory or financing schemes (scenarios) prior to its diffusion, one must understand the dynamic behavior of the entire system with its essential control loops. Aim of this feasibility study was to explore the potential of System Dynamics (SD) modeling for this purpose. First, a UML-based modeling of an Innovative Care for Elderly (ICE) system for provision of integrated social and health care services to elderly living at home was done.

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Dynamic scaling and slowing down in chemical reactions of the critical triethylamine-water system.

J Phys Chem B

February 2007

Drittes Physikalisches Institut, Georg-August-Universitt, Friedrich-Hund-Platz 1, 37077 Goettingen, Germany.

Between 100 kHz and 1 MHz, special ultrasonic attenuation measurements of the triethylamine-water mixture of critical composition have been performed for the determination of the Bhattacharjee-Ferrell scaling function. The experimental data are evaluated considering two noncritical Debye-type relaxation terms as revealed by broadband ultrasonic spectra. Shear viscosity and dynamic light scattering data from the literature are re-evaluated to yield the relaxation rate of order parameter fluctuations of the critical system as a function of temperature.

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End-to-end distribution function of stiff polymers for all persistence lengths.

Phys Rev E Stat Nonlin Soft Matter Phys

March 2005

Institut fr Theoretische Physik, Freie Universitt Berlin, Germany.

We set up recursion relations for calculating all even moments of the end-to-end distance of Porod-Kratky wormlike chains in D dimensions. From these moments we derive a simple analytic expression for the end-to-end distribution in three dimensions valid for all peristence lengths. It is in excellent agreement with Monte Carlo data for stiff chains and approaches the Gaussian random-walk distributions for low stiffness.

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In mixed quantum-classical molecular dynamics few but important degrees of freedom of a dynamical system are modeled quantum-mechanically while the remaining ones are treated within the classical approximation. Rothe methods established in the theory of partial differential equations are used to control both temporal and spatial discretization errors on grounds of a global tolerance criterion. The TRAIL (trapezoidal rule for adaptive integration of Liouville dynamics) scheme [I.

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The pharmacological profiles of the atypical antipsychotics, clozapine, olanzapine, quetiapine and risperidone, all show a combined serotonin (5-HT2) and dopamine type-2 (D2) receptor antagonism. Amisulpride, a highly selective dopamine D2/D3 receptor antagonist that binds preferentially to receptors in the mesolimbic system, is also an 'atypical' antipsychotic despite having a different receptor-affinity profile. A meta-analysis of 18 clinical trials was undertaken to compare the efficacy and safety of amisulpride with conventional antipsychotics.

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The 230-kb human cytomegalovirus genome is among the largest of the known viruses. Experiments to determine the genetic determinants of attenuation, pathogenesis, and tissue tropism are underway; however, a lack of complete sequence data for multiple strains and substantial problems with genetic instability during in vitro propagation create serious complications for such studies. For example, recent findings suggest that common laboratory strains Towne and AD169 passaged in cultured human fibroblasts are missing up to 15 kb of genetic information relative to clinical isolates.

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[Miniature assistance module for robot-assisted heart surgery].

Biomed Tech (Berl)

March 2003

Institut für Feinwerktechnik, Technische Universitt Dresden, 01062 Dresden, Deutschland.

During the robotic enhanced minimally invasive cardiac surgery the approach to and the space for handling instruments in the operating field are usually reduced, compared to the conventional surgery. Additional well knewn problems are the restricted capability available for accessories into and out of the closed chest and the limited assistance during the cardiac procedure. This paper is presenting two solutions of Miniature Modules for supporting the surgeon inside the closed chest.

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