Novel designs for Penning ion traps

We present a number of alternative designs for Penning ion traps suitable for quantum information processing (QIP) applications with atomic ions. The first trap design is a simple array of long straight wires which allows easy optical access. A prototype of this trap has been built to trap Ca+ and a simple electronic detection scheme has been employed to demonstrate the operation of the trap. Another trap design consists of a conducting plate with a hole in it situated above a continuous conducting plane. The final trap design is based on an array of pad electrodes. Although this trap design lacks the open geometry of the traps described above, the pad design may prove useful in a hybrid scheme in which information processing and qubit storage take place in different types of trap. The behaviour of the pad traps is simulated numerically and techniques for moving ions rapidly between traps are discussed. Future experiments with these various designs are discussed. All of the designs lend themselves to the construction of multiple trap arrays, as required for scalable ion trap QIP.Comment: 11 pages, 10 figure

Role of surfactant-induced Marangoni stresses in retracting liquid sheets

In this work, we study the effect of insoluble surfactants on the three-dimensional rim-driven retraction dynamics of thin water sheets in air. We employ an interface-tracking/level-set method to ensure the full coupling between the surfactant-induced Marangoni-stresses, interfacial diffusion, and inertia. Our findings are contrasted with the (Newtonian) dynamics of a liquid sheet edge finding that the surfactant concentration can prevent, or delay, the breakup of the rim. Our simulations use the fastest growing Rayleigh-Plateau instability to drive droplet detachment from the fluid sheet (rim). The results of this work unravel the significant role of Marangoni stresses in the retracting sheet dynamics at large elasticity numbers. We study the sensitivity of the dynamics to the elasticity number and the rigidification of the interface

Optically transparent solid electrodes for precision Penning traps

We have conceived, built, and operated a cryogenic Penning trap with an electrically conducting yet optically transparent solid electrode. The trap, dedicated to spectroscopy and imaging of confined particles under large solid angles is of 'half-open' design with one open endcap and one closed endcap that mainly consists of a glass window coated with a highly transparent conductive layer. This arrangement allows for trapping of externally or internally produced particles, yields flexible access for optical excitation and efficient light collection from the trapping region. At the same time, it is electrically closed and ensures long-term ion confinement under well-defined conditions. With its superior surface quality and its high as well as homogeneous optical transmission, the window electrode is an excellent replacement for partially transmissive electrodes that use holes, slits, metallic meshes and the like

233 A novel ex vivo skin culture device enables clinically representative skin testing

Dermatology has the poorest rate of successful bench-to-clinic transitions. In part this is due to safety testing being historically performed on unrepresentative animal models, or animal replacement tests that use animal, rather than human data as the benchmark for efficacy. As a result, preclinical models are unable to faithfully replicate human responses. Here, we examined whether a novel environmentally relevant skin culture device is able to better mimic human responses for skin permeation and irritation. We engineered a biphasic fluidic culture device combining regulation of atmospheric air, humidity, temperature, pH and media flow, replicating the physiological environment of human skin. Using this device, we assessed the permeation of caffeine and ibuprofen in ex vivo skin at baseline and in skin cultured for five days and found no significant difference in absorption profiles (p 0.05 ANOVA with Dunnet’s multiple comparisons test). Additionally, we assessed the skin irritation potential of compounds, developing methodology based on the approved OECD 439 skin irritation test. Approved validation chemicals, and compounds incorrectly categorised with approved models were assessed. The validation chemicals were correctly categorised (100% accuracy), and the results of the incorrectly categorised compounds fully replicated published human clinical data. In conclusion, physiologically relevant skin culture was essential for maintaining ex vivo skin function and clinically relevant skin responses. Using skin permeation and irritation as examples, we demonstrate this methodology should replace traditional culture methods for the development of accurate, human-representative preclinical analysis for confident bench-to-clinic transitions.</p