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Notes: The response times of nonresonant p-Ge detectors and of resonant photon-drag detectors made from AlxGa1−xAs/GaAs multiquantum well systems are measured with intense 300-ps optical pulses of 10-μm wavelength generated with the aid of an improved laser system based on optical free induction decay. A response time limited by the oscilloscope-amplifier bandwidth is reached with the quantum well systems. Their response time is shorter than that of a p-Ge photon-drag detector. The light-pulse traveling time limits the performance of the large p-Ge photon-drag detectors.

Notes: Abstract In this paper we describe the experimental investigation of the post-breakdown development of a helium plasma generated by a hybrid 10 μm CO2 laser pulse. As a result we found that a long tail and a high energy of the CO2 laser pulse cause multiple successive breakdown in the gas. We have measured the time to the first breakdown and the time between first and second breakdown as functions of gas pressure and laser pulse peak intensity as well as the spatial intensity distribution of the transmitted laser pulse. Among the relevant mechanisms self-focusing is not observed before the second breakdown.

Notes: Abstract We have studied second-harmonic generation by 30 ps and 70 ns 10 μm CO2 laser pulses in nonlinear polycrystalline ZnSe, CdTe and GaAs samples. Second-harmonic generation in these materials can limit the amplification of high-power CO2-laser pulses in amplifier chains sealed with these polycrystalline IR-transmission materials. On the other hand, we now demonstrate for the first time that these materials are suited as nonliner elements for autocorrelation measurements on short infrared laser pulses. For such pulse-width measurements polycrystalline materials have an advantage over single crystals, e.g. GaAs, because they are insensitive to misalignement. Furthermore, these polycrystalline optical elements are easier and cheaper to manufacture than single crystal devices. With such polycrystalline materials we were able to realize reliable autocorrelation measurements of 30–300 ps 10 μm optical-free-induction-decay (OFID) laser pulses.

Notes: Abstract We investigate the generation of superradiant far-infrared 496 μm CH3F pulses and produce for the first time smooth and reproducible 373 μm CH3CN superradiant pulses by pumping with pulses from a hybrid 10 μm CO2 laser truncated within ≈10 ps by a plasma shutter of new design. Superradiance is confirmed by measurement of the pressure dependence of the intensity, the width and the delay versus the pump pulse. We observe pulse durations considerably under the limit of the inverse linewidth of the transition. Thus, we demonstrate for the first time that rapid truncation of the pump pulse is essential for reducing pulse duration of superradiant far-infrared emissions.

Notes: Conclusions and Summary The authors begin with a historical review of the first genetic investigations concerning familial amyloidotic polyneuropathy in the North of Portugal by C. Andrade. Then they review the studies made by other authors about this curious hereditary disease. A dominant mode of transmission was found in all investigations and the area of Povoa de Varzim could be confirmed as the focus where the mutation took place for the first time. Later on the affection spread throughout the northern part of Portugal before finally migrating also to the American continent. The early inquiries of Andrade in 1951–52 were concerned with a still fairly limited number of cases (74 cases). A systematic genetic and statistical study became, however, necessary for the whole material collected over almost 30 years by C. Andrade et al. The individuals examined now amount to 623, 249 of whom are affected (153 males and 96 females, distributed over 148 sibships). After applying various methods of correction (maximum-likelihood-method and Weinberg's method) and while making a distinction between simple selection (k=0) and complete selection (k=1), the authors come to the following evaluations: for K=0, the average of individuals affected (corrected) per sibship is of 21.26±1.88% (method of maximum likelihood scores); for k=1, this value is of 30.84±2.26%. When considering separately within the sibships the male and female patients, the following figures are obtained: for k=0, respectively 13.06±1.33% for males and 8.20±0,98% for females; for k=1, 18,95±1.68% for males and 11.89±1.29% for females. The percentages obtained with Weinberg's method are more or less the same (21.26±1.75% and 31.39±2.50% for k=0 and k=1, respectively). Since the material was collected during a systematic survey of all families affected, the figures computed for k=1 (complete selection) must be considered correct (30.8% by the maximum-likelihood-method and 31.4% by Weinberg's method). In respect of the sex ratio in the families studied, a predilection for the male sex was revealed when all families with at least one member affected are taken into account. However, when considering the families with at least two members affected, the sex ratio corresponds to 1:1. As to morbidity risk, our values are clearly below those of Becker (1964): whereas the figures found by Becker range between 0.32 and 0.50, ours lie between 0.26 and 0.31. The discrepancy must be attributed to the fact that our material which was numerically more important than Becker's provided for a more equitable evaluation of the sex ratio and excluded the possibility of a sex controlled gene. According to our investigations, there is therefore no difference between the sexes as to the degree of penetrance of the affection. The discordance between the sexes is practically restricted to the age of manifestation of the disease, 33 years on an average for males and 44 years for females. The assumption must consequently be made that this one difference is sufficient to guarantee transmission of amyloidotic polyneuropathy through the generations, in spite of counterselection that operates to the detriment of the responsible gene.

Notes: Summary Unicameral bone cysts in 57 patients, seen at the Alfred I. duPont Institute between 1949 and 1982, were studied retrospectively. We present the natural history in several patients and report a “cyst index” which allows the progress of the cyst to be followed and makes it possible to determine whether there is a significant risk of fracture which would warrant treatment. We have found that measuring the cyst index in patients treated by injections of methylprednisolone acetate helps to assess the response to treatment.

Notes: Summary A seven year old boy presented with locking of the left hip after a minor fall. An arthrogram demonstrated a bucket handle tear of the acetabular labrum, and this was confirmed at arthrotomy. The mechanism, management and prognosis of this injury is discussed.