Electro-optic field mapping system utilizing external gallium arsenide probes

External electro-optic probes fabricated from two different crystal orientations of GaAs have been implemented in an electro-optic sampling system that is capable of mapping three independent orthogonal components of free-space electric fields. The results obtained for the radiated field from a microstrip patch antenna by the GaAs probes are compared with results on the same antenna obtained using bismuth silicate and lithium tantalate probes. An 8 μm spatial resolution has also been demonstrated for the electro-optic field-mapping system, and the capability for the system to measure field patterns at frequencies up to 100 GHz has been shown. © 2000 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70294/2/APPLAB-77-4-486-1.pd

Severe conjunctivochalasis in association with classic type Ehlers-Danlos syndrome.

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: Inferior conjunctivochalasis is common, but is rarely severe enough to require conjunctival excision. This report describes a patient with severe conjunctivochalasis who was subsequently diagnosed with Ehlers Danlos Syndrome, Classic Type. CASE PRESENTATION: A patient suffering from foreign body sensation, frequent blinking and bilateral inferior conjunctivochalasis was referred and treated by topical ocular lubrication. However, no improvement was observed prompting potential excision of conjunctivochalasis. Following patient consultation and clinical diagnosis including hypermobile joints and skin elasticity, poor wound healing and wide scar morphology, Ehlers-Danlos syndrome was confirmed in the patient. CONCLUSION: This case highlights the need for direct patient questioning and provides the first reported association between conjunctiovochalasis and Ehlers-Danlos syndrome

A fiber‐mounted, micromachined photoconductive probe with 15 nV/Hz1/2 sensitivity

We report the performance of a micromachined, photoconductive‐sampling probe that is fabricated on low‐temperature‐grown GaAs and mounted on a single‐mode optical fiber. The epitaxial probe has a temporal resolution of 3.5 ps, a spatial resolution of 7 μm, and a sensitivity of 15 nV/(Hz)1/2 when integrated with a high impedance, junction field‐effect transistor source follower. The fiber, which couples short laser pulses to the interdigitated detector pattern on the probe, also provides flexible support and mobility. The probe’s compact cross section makes it ideal for applications as an internal‐node, picosecond‐response, photoconductive sampling probe or wave form launcher for test and characterization of integrated circuits. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70779/2/APPLAB-69-13-1843-1.pd

A field‐sensitive photoconductive probe for sampling through passivation layers

A field‐sensitive photoconductive sampling technique has been demonstrated in measurements performed through an insulating layer without the need for conductive contact. Sampled signals are sensed by a virtual‐ground, floating‐gate amplifier without draining charge from the device under test or the photoconductive switch. The minimum detectable signal is 2.5 μV/Hz1/2 with a spatial resolution of 7 μm, while the sampling bandwidth is essentially that observed using photoconductive sampling with a conductive contact to the device under test. The photovoltaic and shot current noise are negligible in comparison with the lock‐in amplifier noise since the current flowing in this high‐impedance, floating‐gate probe is negligible. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70307/2/APPLAB-69-15-2211-1.pd

A photoconductive, miniature terahertz source

We discuss the performance of a micromachined, photoconductive terahertz emitter that is fabricated on low-temperature-grown GaAs. The device is mounted on a pair of single-mode optical fibers that allows the source to be freely positionable. A strong radiation burst is emitted due to the large magnetic moment created by the electrode. The emitter’s small feature size of 300 μm by 300 μm with a photoconductive switch area of 30 μm by 30 μm suggests its application for terahertz, time-domain, near-field spectroscopy and imaging. © 1998 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70594/2/APPLAB-72-24-3100-1.pd

Branched amphiphilic peptide capsules: Cellular uptake and retention of encapsulated solutes

Branched amphiphilic peptide capsules (BAPCs) are peptide nanospheres comprised of equimolar proportions of two branched peptide sequences bis(FLIVI)-K-KKKK and bis(FLIVIGSII)-K-KKKK that self-assemble to form bi-layer delimited capsules. In two recent publications we described the lipid analogous characteristics of our BAPCs, examined their initial assembly, mode of fusion, solute encapsulation, and resizing and delineated their capability to be maintained at a specific size by storing them at 4 °C. In this report we describe the stability, size limitations of encapsulation, cellular localization, retention and, bio-distribution of the BAPCs in vivo. The ability of our constructs to retain alpha particle emitting radionuclides without any apparent leakage and their persistence in the peri-nuclear region of the cell for extended periods of time, coupled with their ease of preparation and potential tune-ability, makes them attractive as biocompatible carriers for targeted cancer therapy using particle emitting radioisotopes. This article is part of a Special Issue entitled: Interfacially active peptides and proteins

Erratum: ‘‘Picosecond large‐signal switching characteristics of a pseudomorphic AlGaAs/InGaAs modulation‐doped field‐effect transistor’’ [Appl. Phys. Lett. 61, 1187 (1992)]

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70138/2/APPLAB-61-26-3194-1.pd

Picosecond large‐signal switching characteristics of a pseudomorphic AlGaAs/InGaAs modulated doped field effect transistor

We present the first comprehensive study of the large‐signal switching characteristics of an AlGaAs/InGaAs modulation‐doped field‐effect transistor on a picosecond time scale. Electro‐optic sampling is used to measure drain voltage response to a steplike gate input with a 2.8 ps rise time, at various dc biases. A large‐signal switching time of 6.2 ps is obtained. Features deleterious to high‐frequency device operation are observed, related to equivalent circuit parameters, and reduced by appropriate choice of operating point.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69803/2/APPLAB-61-10-1187-1.pd