Search

The molecular beam epitaxy (MBE) growth technology is inherently flexible in its ability to change the Hg1−xCdxTe material’s bandgap within a growth run and from growth run to growth run. This bandgap engineering flexibility permits tailoring the device architecture to the various specific requirements. Material with active layer x values ranging from ∼0.198 to 0.570 have been grown and processed into detectors. This wide range in x values is perfectly suited for remote sensing applications, specifically the National Polar Orbiting Environmental Satellite System (NPOESS) program that requires imaging in a multitude of infrared spectral bands, ranging from the 1.58 to 1.64 µm VSWIR (very short wave infrared) band to the 11.5 to 12.5 µm LWIR (longwave infrared) band and beyond. These diverse spectral bands require high performance detectors, operating at two temperatures; detectors for the VSWIR band operate near room temperature while the SWIR, MWIR (mid wave infra red), LWIR and VLWIR (very long wave infrared) detectors operate near 100K, because of constraints imposed by the cooler for the NPOESS program. This paper uses material parameters to calculate theoretical detector performance for a range of x values. This theoretical detector performance is compared with median measured detector optical and electrical data. Measured detector optical and electrical data, combined with noise model estimates of ROIC performance are used to calculate signal to noise ratio (SNR), for each spectral band. The SNR are compared with respect to the meteorological NPOESS system derived focal plane. The derived system focal plane requirements for NPOESS are met in all the spectral bands.

We present an extension of the surgical approach for harvesting the lateral upper arm free flap by which an additional 6 to 8 cm of pedicle length may be gained. First, the flap is raised by the standard lateral approach. Then, by proceeding proximally and posteriorly, the triceps muscle is split between its lateral and long heads to expose the entire length of the profunda brachii vessels in the spiral groove. A tunnel is developed beneath the lateral head of the triceps, and the flap or its pedicle is delivered through this. We describe the surgical technique and present details of a dissection study on 25 fresh cadaver limbs. The nerve branches to the lateral head of the triceps, which are close to the vessels of the flap, are highly variable in number and location. When unusually short and distally placed, they are at risk of damage, but damage can be avoided if the tunnel is not unduly widened. We present our early clinical experience in 10 consecutive cases using the extended-pedicle lateral arm flap. The free pedicle length in this series ranged from 8 to 13 cm. The maximum flap size was 5 x 19 cm. All cases were successful, although one required reoperation for venous thrombosis. Although postoperative testing of upper arm muscle function showed some weakness and impaired endurance, this was found equally in the surgically disturbed triceps and in the untouched elbow flexors and thus could not be attributed to motor nerve damage to the triceps muscle.

Revascularization of distal occlusive disease in the diabetic has been markedly enhanced by microsurgical techniques. Extremely small, heavily calcified vessels are able to be reliably reconstructed using microsurgical techniques and high magnification. Additionally, revascularization followed by microsurgical free tissue transfer has proven to be a valuable alternative to amputation in patients with major soft-tissue loss, or bony or tendon lesions requiring soft-tissue reconstruction. Although metabolic risks are potentially high, we have experienced a very low morbidity and mortality with a thorough medical work-up and follow-through in conjunction with these major procedures. It is our expectation that judicious application of microsurgical techniques in treatment of the ischemic diabetic lower extremity will continue to improve the chances for long-term bipedal ambulation in this patient population.

V-Y advancement modification of skin paddle design for the biceps femoris, tensor fascia lata, transverse lumbar, and gracilis flaps permits readvancement of each of these flaps for recurrent pressure ulcers. Our use of this refinement of these flaps over the past twelve years shows that up to two readvancements of each of these flaps can be done, thus preserving reconstructive options in a patient population prone to pressure ulcer recurrence.