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Various studies are conducted to measure the radiometric properties, as well as to present the single-pixel and focal plane array characterization of two midwave infrared photodiode arrays, which consists of a thin doped superlattice. The analysis proves the uniformity and good crystal quality of the type II superlattice material, as the layer is thin enough to be fully depleted at zero bias that also increases the efficiency of carriers in the intrinsic region close to unity.

We have studied the effects of AlGaAs energy barriers surrounding self-assembled InAs quantum dots in a GaAs matrix on the properties of solar cells made with multiple quantum dot layers in the active region of a photodiode. We have compared the fenced dot samples with conventional InAs/GaAs quantum dot solar cells and with GaAs reference cells. We have found that, contrary to theoretical predictions, the AlGaAs fence layers do not enhance the transport properties of photogenerated carriers but instead suppress the extraction of the carriers excited in the dots by light with wavelengths longer than the cutoff wavelength of the GaAs matrix material. Both the standard quantum dots and the fenced dots were found to give solar cell performance comparable to the GaAs reference cells for certain active region thicknesses but neither showed enhancement due to the longer wavelength absorption or improved carrier transport. [ABSTRACT FROM AUTHOR]

We have studied electric field induced (Stark) shifts in mid-infrared (IR) transitions that occur in type II AlSb/InAs/GaSb quantum wells. Because of the spatial separation of the electron and hole wave functions in the type II system, the potential drop between the layers dominates the shift in the real-space-indirect transition energies when an external electric field is applied. This can result in either a redshift or a blueshift, depending on the ordering of the quantum well layers within the intrinsic region of a p-i-n diode. The case in which a reverse bias on the diode yields a blueshift in the transition energy is of particular interest for IR electro-optic device applications. The modulator section of an integrated source/waveguide modulator would strongly absorb at zero bias and could be biased into transparency, and bistable optical switches could be made more efficient than with redshifting devices. We have used low temperature current-voltage, capacitance-voltage, and photocurrent measurements to characterize a type II quantum well structure that exhibits a blueshift in the lowest energy transitions that is roughly linear with applied bias and is comparable to the potential drop across the structure. [ABSTRACT FROM AUTHOR]

STUDY DESIGN: :A prospective descriptive study of the course of recovery of reflexes following acute spinal cord injury (SCI). OBJECTIVES: :The purpose of the study was to observe the pattern of reflex recovery following acute SCI in order to determine the prognostic significance of reflexes for ambulation and their relationship to spinal shock. SETTING: :A regional spinal cord injury center in Philadelphia, Pennsylvania, USA. METHODS: :Fifty subjects admitted consecutively over a 9 month period and on the day of injury were observed for the following reflexes; bulbo-cavernosis (BC), delayed plantar response (DPR), cremasteric (CRM), ankle jerk (AJ), knee jerk (KJ), and normal plantar response for 5–7 days a week and 6–8 weeks duration. The 50 subjects were assessed for ambulation of 200 feet at time of discharge. MRI studies were reviewed on 13/28 complete (ASIA A) injuries. RESULTS: :Thirty-five subjects (28 ASIA A, 4 ASIA B, 3 ASIA C) had a DPR of 2 days or longer duration and these subjects were not ambulatory. The fourteen subjects (12 ASIA D and 2 ASIA C), who were ambulatory, either had no DPR (11/14) or had a DPR of only 1 days duration (3/14). One subject (ASIA B) was not ambulatory and had a DRP of 1 days duration. The DPR was the first reflex to recover most often, followed by the BC, CRM in the first few days and later followed by the deep tendon reflexes (AJ & KJ) by 1–2 weeks respectively. Less than 8% of subjects had no reflexes on the day of injury and the reflexes did not follow a caudal-rostral pattern of recovery. CONCLUSIONS: :Prognosis for ambulation based on reflexes early after SCI should not be linked to current descriptions of spinal shock. In fact, the view of spinal shock, based on the absence of reflexes and the recovery of reflexes in a caudal to rostral sequence, is of limited clinical utility and should be discarded. The evolution of reflexes over several days following injury may... [ABSTRACT FROM AUTHOR]

The article discusses the results of a study of the effect of amphetamine sulfate or benzedrine on mentally deficient children, presented at the 64th annual meeting of the American Association on Mental Deficiency in Atlantic City, New Jersey on May 22, 1940. The study aims to determine the effect of a small daily dose of benzedrine during a protracted period on those capacities of mentally retarded children. The study also aims to determine whether gain would appear in psychologically measurable skills when a high dosage of benzedrine was administered only once to children of like intelligence.

Rats fed large quantities of molybdenum for several weeks suffered connective tissue disturbances as revealed by reduced breaking strength of femurs, rupture strength of skin samples, and other tests. [ABSTRACT FROM AUTHOR]