Switching between different vortex states in 2-dimensional easy-plane magnets due to an ac magnetic field

Using a discrete model of 2-dimensional easy-plane classical ferromagnets, we propose that a rotating magnetic field in the easy plane can switch a vortex from one polarization to the opposite one if the amplitude exceeds a threshold value, but the backward process does not occur. Such switches are indeed observed in computer simulations.Comment: 4 pages, 4 figures, submitted to Phys. Rev. Let

Dynamics of topological solitons in two-dimensional ferromagnets

Dynamical topological solitons are studied in classical two-dimensional Heisenberg easy-axis ferromagnets. The properties of such solitons are treated both analytically in the continuum limit and numerically by spin dynamics simulations of the discrete system. Excitation of internal mode causes orbital motion. This is confirmed by simulations.Comment: LaTeX, 15 pages, 6 figure

Noise-induced switching between vortex states with different polarization in classical two-dimensional easy-plane magnets

In the 2-dimensional anisotropic Heisenberg model with XY-symmetry there are non-planar vortices which exhibit a localized structure of the z-components of the spins around the vortex center. We study how thermal noise induces a transition of this structure from one polarization to the opposite one. We describe the vortex core by a discrete Hamiltonian and consider a stationary solution of the Fokker-Planck equation. We find a bimodal distribution function and calculate the transition rate using Langer's instanton theory (1969). The result is compared with Langevin dynamics simulations for the full many-spin model.Comment: 15 pages, 4 figures, Phys. Rev. B., in pres

Erfahrungen mit dem Nano-Laser-Phakoemulsifikationssystem in der Kataraktchirurgie (K)

The aim of the thesis was to generate Aspergillus-specific monoclonal antibodies (mAbs) and corresponding scFv-antibody fragments, while the recombinant scFv antibodies should be fused to antifungal peptides (AFPs). Maize plants transformed with AFP-scFv fusion constructs should posses an increased resistance against aflatoxigenic fungi in Zea mays. Mice were immunized with cell wall fragments of A. flavus and A. parasiticus to generate hybridoma cell lines secreting Aspergillus-specific mAbs, which were characterized by ELISA, immunoblot and immunofluorescence microscopy. Highest reactivity against A. flavus und A. parasiticus was obtained by mAbAP3, mAbAF1 and mAbAP10, while these mAbs were not reactive to other tested fungi except Aspergillus spp. The antibody-encoding cDNA sequences of the three mAbs were identified and functional recombinant scFvs were produced in N. tabacum. The antigen of mAbAP10, the cysteine-rich secreted protein (CSP; XP 002374495.1) was isolated by immunoaffinity chromatography and the effect of CSP-specific siRNA was analyzed against A. flavus and A. parasiticus. Full inhibition of fungal germination was observed for both pathogens at 0.5-1 nM CSP-specific siRNA. Therefore CSP could be used as a target to generate Aspergillus and aflatoxin-resistant crop plants.For the first time, a strong reduction of fungal germination could be demonstrated for A. flavus (MIC 4 µM) und A. parasiticus (MIC 12.5 µM) using thanatin. Since the functionality of transient-produced thanatin- and chitinase-scFv fusion proteins could be confirmed, these fusion constructs and appropriate control constructs were used for stable transformation in maize. After transformation the integration of all constructs into the genome of maize could be confirmed by PCR. To analyze the resistance of transgenic maize, obtained seeds were tested in kernel screening assay against A. flavus. Compared to inoculated wild type seeds an exclusive expression of Aspergillus-specific scFvAP3 did not lead to an increased resistance against A. flavus. However, a three-fold higher resistance against A. flavus could be detected for transgenic seeds expressing both chitinase and thanatin as well as the chitinase- and thanatin-scFv fusion constructs

Potential of the 1 CU accommodative intraocular lens

Aim: To assess the accommodative power of a new foldable monofocal intraocular lens. Method: A prospective randomised non-masked clinical interventional study. The study included 40 patients attending the hospital for cataract surgery and who were randomly distributed into a study group receiving a new foldable monofocal intraocular lens with flexible haptics, and a control group receiving a standard foldable intraocular lens. Mean follow up period was 8.51 (SD 1.34) months (range 4–11 months) Standard cataract surgery consisted of clear cornea incision, capsulorrhexis, phacoemulsification, and intraocular lens implantation, with topical anaesthesia. The main outcome measures were preoperative and postoperative visual acuity for near and distance; range of accommodation; change in anterior chamber depth. Results: In the study group compared with the control group, range of accommodation was significantly (p = 0.01) higher (1.01 (SD 0.4) dioptres versus 0.50 (0.11) dioptres) and change in anterior chamber depth was significantly more pronounced (0.82 (0.30) versus 0.40 (0.32), p = 0.01). Both groups did not vary significantly in best corrected vision (0.94 (0.12) versus 0.93 (0.18); p = 0.74). Conclusion: During a mean follow up period of 8 months after implantation, the new foldable monofocal intraocular lens with flexible haptics showed an accommodative power of about 1 dioptre, which was significantly higher than the accommodative power of a conventional monofocal flexible intraocular lens. The difference in the accommodative power between the two intraocular lenses was paralleled by a difference in the change of the anterior chamber depth