Opiate users and the first years after treatment: outcome analysis of the proportion of follow up time spent in abstinence

This second report on a follow-up study of drug users focuses on changes that occurred on a number of variables between intake and follow-up and during the follow-up period. The length of abstinence from opiates was considered as a proportion of the total follow-up period. Overall there was a reduction in opiate use, in injecting and sharing equipment at follow-up. There had been, however, a high level of these risky activities during the follow-up period. Sustained abstinence from opiates was associated with increased employment, enhanced social stability and mental health. Intake drug use was strongly related to follow-up drug status. In particular, those who were injectors of multiple drugs at intake were far less likely to be long term opiate abstainers at follow-up than those who were not injectors at intake or injectors of opiates only.     

Discussion of “an interpretation of the carbon redistribution process during aging of high-carbon martensite”

Y. OHMORI and I. TAMURA:Metall. Trans. A, 1992, vol. 23A,     

Use of acetabular models in planning complex acetabular reconstructions

The number of patients requiring revision total hip arthroplasty continues to increase each year. Accurate preoperative planning is a key factor in obtaining a good result. Radiographs provide little information concerning the actual extent of the acetabular defects. Computed tomography-generated models of the acetabulum can provide the surgeon with accurate information concerning the size and location of the defects. Evaluation of radiographs and models in 24 cases showed that radiographs alone failed to detect all 13 anterior wall defects (P < .001), 8 of 18 posterior wall defects (44.4%, P < .001), and 8 of 19 segmental central defects (42%, P < .001), all of which were easily identified with the models. This study showed that preoperative planning based on the foam models accurately predicted the actual implant used in 22 of 24 cases (92%).     

Design and evaluation of an optically triggered monolithic sampleand hold circuit using GaAs MESFET technology

The design and evaluation of an optically triggered, fully integrated sample and hold circuit (OS/H) is described. Measured results are presented that demonstrate operation of this circuit at 250 Ms/s and with effective resolution approaching 8 bits. The integrated circuit, which measures 2.1 mm×1.4 mm, is realized in -1.0-V threshold, 20-GHz ft GaAs MESFET technology, consumes approximately 200 mW of power, and requires one optical address. The OS/H will find applications in high precision, hybrid, and integrated signal processing systems where high speed, high levels of parallelism, and low timing jitter are important. Measured results of a series photoconducting (Auston switch) OS/H realized in the same technology are presented for comparison purposes     

A set of electrophoretic molecular markers for strain typing and population genetic studies of Histoplasma capsulatum

A set of eleven biallelic and three multiallelic molecular markers have been developed to analyze populations of Histoplasma capsulatum. All markers are amplified by polymerase chain reaction (PCR) and can be readily scored using minimal amounts of template DNA. The 11 biallelic loci have polymorphic restriction endonuclease sites or small insertions or deletions which may be assessed by agarose gel electrophoresis. These markers are inherited in an unambiguous manner and are ideal for assessing structure and gene flow within US populations of H. capsulatum, but are monomorphic in non-US populations. Both length and sequence variation are present in the multiallelic loci, which can be scored by direct sequencing, polyacrylamide gel electrophoresis, or single-strand conformation polymorphism (SSCP): As they are hypervariable, the multiallelic loci can be used to type isolates and to assess the level of genetic variation within populations. Preliminary results indicate that the three multiallelic markers presented are sufficient to distinguish isolates at the individual level and are polymorphic in both US and non-US populations. This collection of molecular markers will be a useful tool in population and epidemiology studies of H. capsulatum.     

Influence of low-frequency electromagnetic fields on living organisms

Recent research reports appear to indicate a real possibility that the low-frequency electromagnetic field produced by the power transmission and distribution network presents a health problem. A critical assessment of the available information is presented here. The state of knowledge, available evidence and conflicting reports indicate a definite need for interim action by the power industry. New direction for analytical research, possible interim avoidance measures, proper advice to clients and the public are discussed. Detailed mathematical modeling for the linear and nonlinear dynamics of DNA and the chromosome as a whole is suggested.     

A quantum amplifier model for predicting temporal variations in theoutput power from a semiconductor laser on a picosecond time scale

A new model for simulating temporal fluctuations in the power emitted by a semiconductor laser is described. Light in the cavity is assumed to circulate in the form of traveling photon packets, in which the photon number fluctuates due to the processes of spontaneous emission, stimulated emission, absorption, scattering, and reflection. The dipole dephasing time T plays a critical role in modeling the interaction of the photon packets and gain medium. The Monte Carlo method is used to simulate the temporal behavior of a continuously pumped Fabry-Perot laser. The laser output power is found to exhibit periodic fluctuations at the cavity transit time frequency (longitudinal mode beat frequency). The amplitude of these fluctuations, as well as the relaxation oscillation, which occurs at a much lower frequency, is strongly influenced by the magnitude of T. The results of these simulations are related to the temporal behavior expected from a conventional FP laser