Effect of length of gestation on maternal cellular immunity to human trophoblast antigens

Maternal lymphocyte reactivity to human trophoblast antigens was studied in placentas of gestational ages 8 to 14 weeks and 32 to 34 weeks, respectively. Significant trophoblast lysis became apparent after 24 hours' incubation in the latter case compared with a time lag of 72 hours in the terminated gestations. Maternal cellular immunity, therefore, was not detected during the first 3 1/2 months of pregnancy, but was detectable by the time of parturition. The possible significance is discussed with respect to the antigenic stimulus and survival of the fetal allograft.     

A periodic pulsed relativistic backward wave oscillator mechanically tunable in an expanded frequency band

We have studied a periodic pulse train regime (1 s, 50 Hz) of a relativistic backward wave oscillator with a resonant reflector, which can be mechanically tuned from pulse to pulse within a frequency band of 9% on a level of ?3 dB of the maximum in the entire microwave peak power range in a magnetic field of 0.36 T. The maximum peak power in a pulse train amounted to 2.5 GW at a frequency of 3.6 GHz, an efficiency of 20%, and a microwave pulse duration of 20 ns.     

Progressive systemic sclerosis: intrathecal pain management

PURPOSE: To determine if lucanthone crossed the blood-brain barrier in experimental animals; and to determine accelerated tumor regression of human brain metastases treated jointly with lucanthone and whole brain radiation. METHODS AND MATERIALS: The organ distribution of 3H lucanthone in mice and 125I lucanthone in rats was determined to learn if lucanthone crossed the blood-brain barrier. Size determinations were made of patients' brain metastases from magnetic resonance images or by computed tomography before and after treatment with 30 Gy whole brain radiation alone or with lucanthone. RESULTS: The time course of lucanthone's distribution in brain was identical to that in muscle and heart after intraperitoneal or intravenous administration in experimental animals. Lucanthone, therefore, readily crossed the blood-brain barrier in experimental animals. CONCLUSION: Compared with radiation alone, the tumor regression in patients with brain metastases treated with lucanthone and radiation was accelerated, approaching significance using a permutation test at p = 0.0536.     

Universal application of heat-resistant ferrite steels in various sectors of industry

The experience and prospects of using economically alloyed chromium steels in various fields of machine building are discussed. The main trends in improving the service resistance of products owing to new metallurgical, design, or technological solutions are identified.     

Effect of Low-Temperature Diffusion Annealing on the Properties of PbSnTe〈In〉 Epilayers

A procedure was proposed for low-temperature vapor-phase In doping of Pb_{1 – x} Sn _x Te films grown by molecular-beam epitaxy on BaF₂ substrates. Diffusion annealing was carried out in a hydrogen atmosphere in the presence of a vapor source identical in composition to the film and a dopant source at temperatures which were, in most cases, no higher than the growth temperature (300–460°C). The effect of diffusion annealing on the composition, transport properties, and homogeneity of both undoped and In doped films was examined. The results suggest that indium is transported in the vapor phase in the form of indium tellurides resulting from the reaction between Te vapor and liquid In.