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A 65-year-old male patient presented to the accident and emergency department with generalized upper abdominal pain. Blood tests showed a raised amylase of 1811 IU/l and elevated inflammatory markers (C-reactive protein = 126 mg/l). The patient was found to have a profound metabolic acidosis with a base excess of –16. Also of note was a history of severe alcohol excess. A differential diagnosis was made clinically of pancreatitis or ischaemic bowel and a computed tomography (CT) …

Light pulses from extensive air showers have been studied with a system of four wide-angle detectors in coincidence. The zenith angle distribution has been determined by a timing method, and the rate of showers observed under cloud. Most of the light observed appears to originate from altitudes of less than 1 km. The results can be reconciled with previous work if it is assumed that the angular distribution of the light at emission is very wide; the observed characteristics of the shower are then determined principally by the field of view of the receiver.

Publisher Summary This chapter discusses photography of extensive air showers in the atmosphere. An image intensifier system was used triggered by amplified pulses from a 5-in. photomultiplier in an attempt to photograph the showers. The system consisted of a Schmidt mirror of 30 cm diameter and nominal relative aperture f/0.5, but with usable aperture only 300 cm 2 . It had an acceptance cone of 17° half-angle about the zenith and was focused for infinity on the 5-in. photocathode of an image intensifier. This was run continuously, and integrated night sky light over the decay time of the P·15 phosphor, nominally 1 μsec. Operation was possible under clear sky conditions for a period of 8 h, and 32 shower pulses were observed. A random pulse was applied a few seconds after each Cerenkov pulse to obtain a random comparison picture. Ten of the Cerenkov photographs show bright spots, 2–5° in diameter. Some of these are circular, however some have appreciable ellipticity. The variation of intensity over the spots cannot be measured with the present system.

Upper flux limits at the earth for γ rays of energy greater than about 5 × 1012 eV, have been established for the quasi-stellar sources 3C 147, 3C 196, 3C 273, the Crab Nebula, and the magnetic variable 53 Cam. They are all of the order 10-10 photons cm-2. s-1. Corresponding upper energy limits at emission are of the order 5 × 1047 ergs s-1 for the quasi-stellar sources, and 5 × 1035 ergs s-1 for the Crab Nebula, if γ-ray absorption is assumed negligible. Possible absorption mechanisms are discussed.

The synthesis and study of a series of 6-substituted-2,4-dimethyl-3-pyridinols having interesting antioxidant properties is reported. The general synthetic strategy leading to the compounds involved a low-temperature aryl bromide-to-alcohol conversion as the last step. 2,4-dimethyl-3-pyridinol (1a), 2,4,6-trimethyl-3-pyridinol (1b), and 2,4-dimethyl-6-(dimethylamino)-3-pyridinol (1d) were thus prepared from the corresponding 3-bromopyridine precursor. The methoxy derivative 2,4-dimethyl-6-(methoxy)-3-pyridinol (1c) was also prepared by an alternate route via a Baeyer-Villiger reaction on the substituted benzaldehyde precursor. Novel bicyclic pyridinols 2 and 3 required prior construction of the ring structure. Thus, 2 was prepared by the use of a 6-step intramolecular Friedel-Crafts strategy, and 3 required an 11-step sequence with a thermolytic intramolecular inverse-demand Diels-Alder reaction between a pyrimidine ring and an alkyne as the key step. Basicities of the pyridinols approached physiological pH with increasing electron density in the ring. Pyridinols 1a-d were found to be indefinitely stable to air oxidation while 2 and 3 decomposed upon extended exposure to the atmosphere. The reactivities of the pyridinols toward chain-carrying peroxyl radicals in homogeneous organic solution were examined by studying the kinetics of radical-initiated styrene autoxidations under controlled conditions. These experiments revealed that some of the newly synthesized pyridinols are the most effective phenolic chain-breaking antioxidants reported to date.