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— –The influence of concentration and temperature on the fluorescence quantum yield and lifetime (measured by a monophoton technique) of phenylalanine is studied in neutral aqueous solutions (8 × 10-4-10-1M) over the temperature range 0–70°C. The rate constants for emission, internal conversion and intersystem crossing are evaluated and show that both non radiative processes contribute efficiently to the deactivation of the singlet state. Evidence for excited dimer formation at high concentration is presented. The binding energy of excimers was found to be 0.19 e V.

Digitalis, when given to the healthy human subject in therapeutic doses and under experimental conditions laid down in this study seems to exert slight, if any, diuretic effect. The diuretic effect of digitalis in cases of cardiac failure with edema is uncertain; such effect may be marked, slight, or absent. It is suggested that in the treatment of congestive heart failure and edema digitalis be employed for its beneficial cardiac effect, and that other substances be also employed for their superior and more certain diuretic action.

Electronic energy transfer at the singlet level in poly-DL-phenylalanine was studied by comparing the experimental and theoretical values of the rate constants of fluorescence quenching by CCl4 and of energy transfer on a fluorescent acceptor (biacetyl). The fitting of the experimental and calculated values leads to a diffusion coefficient of the excitation energy of 3.8 to 4.8 × 10−5 cm2/s, consistent with 40 residues implied in the migration process.

A study of the Attitude Control System (ACS) is made for a solar electric propulsion geosynchronous transfer mission. The basic mission considered is spacecraft injection into a low altitude, inclined orbit followed by low thrust orbit changing to achieve geosynchronous orbit. Because of the extended thrusting time, the mission performance is a strong function of the attitude control system. Two attitude control system design options for an example mission evolve from consideration of the spacecraft configuration, the environmental disturbances, and the probable ACS modes of operation. The impact of these design options on other spacecraft subsystems is discussed. The factors which must be considered in determining the ACS actuation and sensing subsystems are discussed. The effects of the actuation and sensing subsystems on the mission performance are also considered.

The authors report the cases of 2 patients who underwent lobectomy followed by irradiation for lung cancer and subsequently developed an aspergillus-infected cavity in the irradiated lung parenchyma. It is far from certain that aspergillosis must always develop in a pre-existing cavity. In cases where it developed on post-radiotherapy lung lesions, our 2 patients and a review of the literature encline us to believe that the fungus itself is responsible for the formation of cavities in lesions of radiation pneumonia. Treatment of such disease can only be surgical, and in spite of post-irradiation and post-surgery sclerosis, elective excision of the lesions is the best solution.

Zirconium acetate solutions were concentrated in such a manner that short fibers could be obtained from them by extrusion and air-jet drawing. The chemical and structural evolution of these fibers when heated was followed by DT-TGA, X-ray diffraction, IR analysis and SEM observations. Special attention was given to the influence of the firing atmosphere and of the addition to the starting solutions of compounds known to inhibit the allotropic transformations of zirconium oxide. When correctly controlled this evolution was found to lead to fine-grained metastable tetragonal zirconia without major flaws.

The authors presented their observations of four patients who were operated on for a supra-infection of emphysematous bullae by Mycobacterium xenopi. In two cases the patients were operated on without a diagnosis and excision of the right upper lobe assured their cure. The other patient underwent a decortication and ultimately relapsed. The fourth had a bilateral apical infection and underwent bilateral excision. A survey of the literature leads one to think that pulmonary infections with a Mycobacterium xenopi occur in emphysematous bullae more often than is generally thought. The unreliability of the results of antituberculous drugs, the complications of treatment and the risks of recurrence after treatment are well known. Controlled surgical excision of the lesions, which is most often followed by a definitive cure, always merits consideration as part of the therapeutic arsenal.

To assess whether interleukin-2 has a role in the pathogenesis of scleroderma.Observe serum effect on the in-vitro growth of an interleukin-2-dependent cytotoxic T-cell line and determine serum level by an enzyme-linked immunosorbent assay.Outpatient rheumatology clinic of a university medical center.Sera were collected from 47 patients with scleroderma, 20 patients with rheumatoid arthritis, and 14 matched control subjects.A significant mitogenic effect was observed in sera from patients with scleroderma of recent onset; a lower proliferative response was seen in rheumatoid sera. Matched control sera had no mitogenic activity. Sera from patients with scleroderma of recent onset supported the in-vitro growth of an interleukin-2-dependent cytotoxic T-cell line. Matched control sera had no similar mitogenic activity. Interleukin-2 was found in sera from 41 of 47 patients with scleroderma (204 +/- 356 U/mL, mean +/- SD), in 9 of 20 patients with rheumatoid arthritis (2.04 +/- 5.16), and in none of 14 matched control subjects. There was a positive correlation between serum level and the skin progression index (skin score/disease duration).The presence of interleukin-2 in scleroderma sera strongly supports a role for T-cell activation in scleroderma. The association between serum levels and disease progression indicates that this T-cell process may participate in the progression of the disease.

Measurements of atmospheric radio noise have been made in Thailand since early 1966 using equipment similar to the ARN-2 noise-measuring sets employed in the worldwide noise-measuring network coordinated by the Environmental Science Services Administration (ESSA) of the U.S. Department of Commerce. Emphasis is placed in this report on noise power measurements at 0. 53, 2.3, 5.0, and 10.0 MHz. The analysis of data from almost two years of measurements shows that the variation in the magnitude of noise power from day to night in Thailand is typically 25 dB and indicates that a seasonal variation of about 10 dB is superimposed upon the diurnal effect. The day-to-day variation of noise power at any given hour is considerable. An investigation of the effects of local electrical storms--as indicated by lightning-flash counters--shows that the hour by average noise power tends to increase as the number of flash counts increases, and this effect is greater at the lower frequencies.