Contactless conductivity detector array for capillary electrophoresis.

A CE system featuring an array of 16 contactless conductivity detectors was constructed. The detectors were arranged along 70 cm length of a capillary with 100 cm total length and allow the monitoring of separation processes. As the detectors cannot be accommodated on a conventional commercial instrument, a purpose built set-up employing a sequential injection manifold had to be employed for automation of the fluid handling. Conductivity measurements can be considered universal for electrophoresis and thus any changes in ionic composition can be monitored. The progress of the separation of Na(+) and K(+) is demonstrated. The potential of the system to the study of processes in CZE is shown in two examples. The first demonstrates the differences in the developments of peaks originating from a sample plug with a purely aqueous background to that of a plug containing the analyte ions in the buffer. The second example visualizes the opposite migration of cations and anions from a sample plug that had been placed in the middle of the capillary.

A lung-on-chip array with an integrated bio-inspired respiration mechanism

We report about a lung-on-chip array that mimics the pulmonary parenchymal environment, including the thin, alveolar barrier and the three-dimensional cyclic strain induced by the breathing movements. A micro-diaphragm used to stretch the alveolar barrier is inspired by the in-vivo diaphragm, the main muscle responsible for inspiration. The design of this device aims not only at best reproducing the in-vivo conditions found in the lung parenchyma, but also at making its handling easy and robust. An innovative concept, based on the reversible bonding of the device, is presented that enables to accurately control the concentration of cells cultured on the membrane by easily accessing both sides of the membranes. The functionality of the alveolar barrier could be restored by co-culturing epithelial and endothelial cells that formed tight monolayers on each side of a thin, porous and stretchable membrane. We showed that cyclic stretch significantly affects the permeability properties of epithelial cell layers. Furthermore, we could also demonstrate that the strain influences the metabolic activity and the cytokine secretion of primary human pulmonary alveolar epithelial cells obtained from patients. These results demonstrate the potential of this device and confirm the importance of the mechanical strain induced by the breathing in pulmonary research.

Efficient and Robust Host–Guest Antenna Composite for Light Harvesting

We report discovery of a new efficient and robust antenna composite for light harvesting. The organic dye hostasol red (HR) is strongly luminescent in aprotic solvents but only weakly luminescent in potassium zeolite L (ZL) at ambient conditions. We observed a dramatic increase of the luminescence quantum yield of HR–ZL composites if some or all exchangeable potassium cations of ZL are substituted by an organic imidazolium cation (IMZ+) and if the acceptor HR is embedded in the middle part of the channels, so that it is fully protected by the environment of the perylene dye tb-DXP. This led to the discovery of a highly efficient donor,acceptor-ZL antenna material where tb-DXP acts as donor and HR acts as acceptor. The material has a donor-to-acceptor (D/A) absorption ratio of more than 100:1 and a nearly quantitative FRET efficiency. Synthesis of this host–guest material is reported. We describe a successful procedure for achieving full sealing of the ZL channel entrances such that the guests cannot escape. This new material is of great interest for applications in luminescent solar concentrator (LSC) devices because the efficiency killing self-absorption is very low.

Manual Electrode Array Insertion Through a Robot-assisted Minimal Invasive Cochleostomy: Feasibility and Comparison of Two Different Electrode Array Subtypes.

HYPOTHESIS To evaluate the feasibility and the results of insertion of two types of electrode arrays in a robotically assisted surgical approach. BACKGROUND Recent publications demonstrated that robot-assisted surgery allows the implantation of free-fitting electrode arrays through a cochleostomy drilled via a narrow bony tunnel (DCA). We investigated if electrode arrays from different manufacturers could be used with this approach. METHODS Cone-beam CT imaging was performed on fivecadaveric heads after placement of fiducial screws. Relevant anatomical structures were segmented and the DCA trajectory, including the position of the cochleostomy, was defined to target the center of the scala tympani while reducing the risk of lesions to the facial nerve. Med-El Flex 28 and Cochlear CI422 electrodes were implanted on both sides, and their position was verified by cone-beam CT. Finally, temporal bones were dissected to assess the occurrence of damage to anatomical structures during DCA drilling. RESULTS The cochleostomy site was directed in the scala tympani in 9 of 10 cases. The insertion of electrode arrays was successful in 19 of 20 attempts. No facial nerve damage was observed. The average difference between the planned and the postoperative trajectory was 0.17 ± 0.19 mm at the level of the facial nerve. The average depth of insertion was 305.5 ± 55.2 and 243 ± 32.1 degrees with Med-El and Cochlear arrays, respectively. CONCLUSIONS Robot-assisted surgery is a reliable tool to allow cochlear implantation through a cochleostomy. Technical solutions must be developed to improve the electrode array insertion using this approach.

Estimation of satellite antenna phase center offsets for Galileo

Satellite antenna phase center offsets for the GalileoInOrbitValidation(IOV) and FullOperationalCapability (FOC) satellites are estimated by two different analysiscenters based on tracking data of a global GNSS network. The mean x- and y-offsets could be determined with a precision of a few centimeters. However, daily estimates of thex-offsets of the IOV satellites show pronounced systematic effects with a peak-to-peak amplitude of up to 70 cm that depend on the orbit model and the elevation of the Sun above the orbital plane. For the IOV y-offsets, no dependence on the orbit model exists but the scatter strongly depends on the elevation of the Sun above the orbital plane. In general, these systematic effects are significantly smaller for the FOC satellites. The z-offsets of the two analysis centers agree within the 10–15 cm level, and the time series do not show systematic effects. The application of an averaged Galileo satellite antenna model obtained from the two solutions results in a reduction of orbit day boundary discontinuities by up to one third—even if an independent software package is used.