The effect of silver thickness on the enhancement of polymer based SERS substrates.

We investigated silver-covered polymer based nanogratings as substrates for surface-enhanced Raman spectroscopy (SERS), in particular with respect to the thickness of the plasmonically active silver film. In order to obtain accurate geometrical input data for the simulation process, we inspected cross sections of the gratings prepared by breaking at cryogenic temperature. We noticed a strong dependence of the simulation results on geometrical variations of the structures. Measurements revealed that an increasing silver film thickness on top of the nanogratings leads to a blue shift of the plasmonic resonance, as predicted by numerical simulations, as well as to an increased field enhancement for an excitation at 488 nm. We found a clear deviation of the experimental data compared to the simulated results for very thin silver films due to an island-like growth at a silver thickness below 20 nm. In order to investigate the SERS activity. we carried out measurements with crystal violet as a model analyte at an excitation wavelength of 488 nm. The SERS enhancement increases up to a silver thickness of about 30 nm, whereas it remains nearly constant for thicker silver films.

Magnetization reversal in magnetic nanostripes via Bloch wall formation.

We present results of micromagnetic simulations of the magnetization reversal in permalloy nanostripes with 5-10 nm thickness and 200-500 nm width under a longitudinal field of 0.4-16 kA m(-1). The data show four distinct field regions: the well-known regions of uniform and oscillating domain wall movement as well as a process with multiple vortices, and finally a new process including Bloch walls and the generation of vortex-antivortex pairs in the inner part of the stripe rather than at the edges. We investigate this process in detail and derive a criterion for the formation of Bloch walls.

Doubly resonant optical nanoantenna arrays for polarization resolved measurements of surface-enhanced Raman scattering.

We report that rhomb-shaped metal nanoantenna arrays support multiple plasmonic resonances, making them favorable bio-sensing substrates. Besides the two localized plasmonic dipole modes associated with the two principle axes of the rhombi, the sample supports an additional grating-induced surface plasmon polariton resonance. The plasmonic properties of all modes are carefully studied by far-field measurements together with numerical and analytical calculations. The sample is then applied to surface-enhanced Raman scattering measurements. It is shown to be highly efficient since two plasmonic resonances of the structure were simultaneously tuned to coincide with the excitation and the emission wavelength in the SERS experiment. The analysis is completed by measuring the impact of the polarization angle on the SERS signal.

Relationship between nonadiabaticity and damping in permalloy studied by current induced spin structure transformations.

By direct imaging we determine spin structure changes in Permalloy wires and disks due to spin transfer torque as well as the critical current densities for different domain wall types. Periodic domain wall transformations from transverse to vortex walls and vice versa are observed, and the transformation mechanism occurs by vortex core displacement perpendicular to the wire. The results imply that the nonadiabaticity parameter beta does not equal the damping alpha, in agreement with recent theoretical predictions. The vortex core motion perpendicular to the current is further studied in disks revealing that the displacement in opposite directions can be attributed to different polarities of the vortex core.

[On the way to second class medicine?]. / Auf dem Weg zur 2-Klassenmedizin?

A health system that satisfies ethical criteria must apply the principles of equity in allocation of resources, and in addition guarantee unimpeded access to the necessary care for everybody. As to the latter this is vastly realized in the Federal Republic. The same is not true for equity in allocation. There are certain areas which are overprovided and others with deficiencies as for instance care for geriatric and chronic patients. Therefore, we already have a two-class-medicine but should do our best to prevent it from gaining additional ground.

[Therapeutic trial, clinical research and therapy freedom--viewpoint of the ethics committee]. / Heilversuch, klinische Forschung und Therapiefreiheit--Sicht der Ethikkommission.

The necessity to define the above-mentioned terms is due to the fact that legal and administrative regulations pertaining to them are different. To decide on the still ambiguous position of studies to optimize therapy seems desirable.

[Patients with severe multiple handicaps in workshops for the handicapped--a project of the Berlin Workshops for the Handicapped GmbH (BWB) 4 December 1989 to 31 May 1990]. / Schwerstmehrfachbehinderte in Werkstätten für Behinderte--Ein Projekt der Berliner Werkstätten für Behinderte GmbH (BWB) in der Zeit von 4.12.1989 bis 31.5.1990.

A project had been carried out at Berliner Werkstätten für Behinderte GmbH (BWB) aimed at integrating cerebral palsied persons with very severe, multiple disability in a workshop for the disabled. Client workshop readiness had been determined on the criteria of social capacity, extraordinary care need at the workplace, and economic viability of work. The project, planned to last 6 months, had to be discontinued because the 9 disabled persons included in this programme refused to cooperate after a short period of time.

A nursing bioethics program.

In 1985 the Seattle Veterans' Administration Medical Center nursing service implemented a nursing program for bioethics with three goals: (1) to expand the nurse's knowledge of bioethical principles, (2) to develop the nurse's ability and confidence in analyzing bioethical dilemmas, and (3) to increase bioethical application at the bedside. Two psychosocial clinical nurse specialists (CNSs) led this highly successful nursing program that prepared nurses to more actively and responsibly participate in bioethical decision making within the medical center. The program offers an annual workshop for new members, holds a monthly discussion group, conducts a yearly enrichment program, and completes an annual evaluation report. This article describes nursing service bioethics program from planning through evaluation and the role of the CNS as program coordinator, facilitator, and educator in the expanding field of bioethics.