The corneal subbasal nerve plexus and thickness of the retinal layers in pediatric type 1 diabetes and matched controls

Optical coherence tomography (OCT) of the retina and corneal confocal laser scanning microscopy (CLSM) of the subbasal nerve plexus (SBP) are noninvasive techniques for quantification of the ocular neurodegenerative changes in individuals with type 1 diabetes mellitus (T1DM). In adult T1DM patients these changes are hardly related to T1DM only. Instead, ageing and/or lifestyle associated comorbidities have to be considered as putative confounding variables. Therefore, we investigated pediatric T1DM patients (n = 28; 14.2 ± 2.51 y; duration of disease: 5.39 ± 4.16 y) without clinical signs of diabetic retina disease, neuropathy, vasculopathy or nephropathy and compared our findings with those obtained in healthy controls (n = 46; 14.8 ± 1.89 y). The SBP was characterized by the averaged length, thickness, and tortuosity of nerve fibers as well as the number of branching and connecting points. OCT was used to determine the total thickness of the retina (ALL) and the thickness of each retinal layer. Both methods revealed signs of early neurodegenerative changes, e.g. thinning of distinct retinal layers at the pericentral ring and shortening of corneal nerve fibers that are already present in pediatric T1DM patients. Standardization of instruments and algorithms are urgently required to enable uniform comparison between different groups and define normative values to introduce in the clinical setting

Static and dynamic determination of the mechanical properties of nanocrystalline diamond micromachined structures

We present the static and dynamic mechanical characterization of several nanocrystalline diamond (NCD) freestanding micromachined structures. NCD films, fabricated by microwave plasma chemical vapour deposition on silicon (1 0 0), were underetched in order to release the test structures. Two different techniques are combined for the mechanical characterization, atomic force microscopy (AFM) and magnetomotive resonant frequency spectroscopy. The static Young's modulus (E) of the micromachined structures was calculated from the AFM measurements, resulting in E = 947 ± 40 GPa. This value is in excellent agreement with the determination of an acoustic velocity of 17 283 ± 232 m s−1, calculated from the resonance frequency of double-clamped structures and coupled single-clamped U-frame resonators

(AlGaIn)N UV LEDs for integrated metal-oxide based ozone sensors

There is high demand for compact low-cost ozone (O3) sensors. It has been shown that indium oxide (In2O3) thin films grown by metal-organic vapor-phase epitaxy (MOVPE) act as an O3 sensitive material, which can be activated at room-temperature by ultraviolet (UV) light. In the present work we integrated the In2O3 sensing thin film and an (AlGaIn)N based near-UV LED back-to-back on a single sensor chip. The integrated in2O3 film-LED sensor was exposed to varying ozone concentrations ranging from 38 ppb to 726 ppb and found to be sensitive to even the lowest O3 concentration

Integration of thin-film-fracture-based nanowires into microchip fabrication

One-step device fabrication through the integration of nanowires (NWs) into silicon microchips is still under intensive scientific study as it has proved difficult to obtain a reliable and controllable fabrication technique. So far, the techniques are either costly or stiffer from small throughput. Recently, a cost-effective method based on thin-film fracture that can be used as a template for NW fabrication was suggested. Here, a way to integrate NWs between microcontacts is demonstrated. Different geometries of microstructured photoresist formed by using standard photolithography are analyzed. Surprisingly, a very simple "stripe" geometry is found to yield highly reproducible fracture patterns, which are convenient templates for fault-tolerant NW fabrication. Microchips containing integrated Au, Pd, Ni, and Ti NWs and their suitability for studies of conductivity and oxidation behavior are reported, and their suitability as a hydrogen sensor is investigated. Details of the fabrication process are also discussed