Emittance characterization of a hot-cavity laser ion source at Holifield Radioactive Ion Beam Facility.

The first investigation of the transverse emittance of a hot-cavity laser ion source based on all-solid-state Ti:sapphire lasers is presented. The emittances of (63)Cu ion beams generated by three-photon resonant ionization are measured and compared with that of the (69)Ga and (39)K ion beams resulting from surface ionization in the same ion source. A self-consistent unbiased elliptical exclusion method is adapted for noise reduction and emittance analysis. Typical values of the rms and 90% fractional emittances of the Cu ion beams at 20 keV energy are found to be about 2 and 8 pi mm mrad, respectively, for the ion currents of 2-40 nA investigated. The emittances of the laser-produced Cu ion beams are smaller than those of the surface-ionized Ga and K ion beams.

Crystal blocking measurements of the time delay of fission induced by 32S, 48Ti, and 58Ni bombardment of W.

The time delay in fission induced by bombardment of W with 180 MeV 32S, 240-255 MeV 48Ti, and 315-375 MeV 58Ni has been measured by observation of crystal blocking. There is a clear narrowing and a small increase in the minimum yield of the angular dips for fission compared with scaled dips for elastically scattered ions. This is interpreted as a fission delay of about 2 as, only weakly dependent on energy and atomic number. The delay is longer by 1 to 2 orders of magnitude than obtained from standard interpretations of measurements of prescission neutrons and giant-dipole-resonance gamma rays and from calculations of the nuclear dynamics in heavy-ion reactions.

Electromagnetically induced nuclear-charge pickup observed in ultrarelativistic Pb collisions.

A strong increase of inclusive nuclear-charge pickup cross sections, forming 83Bi from 158A GeV 82Pb ions, is observed in comparison to similar measurements at 10.6A GeV. From the dependence of these cross sections on target atomic number, this increase is attributed to the electromagnetic process of pion production by equivalent photons. The observed cross sections can be reproduced quantitatively using the recently developed RELDIS code.

Therapeutic advances in the management of allergic rhinitis and urticaria.

Therapy for patients with allergic rhinitis and urticaria has undergone considerable change in recent years because the mechanisms of these diseases have been more clearly elucidated. Both appear to have marked inflammatory components. A review of the recent literature reveals that clinical studies of both classic and new nonsedating H1-receptor antagonists, H2-receptor antagonists, a variety of intranasal medications, and mast-cell stabilizers demonstrate variable roles in the management of these diseases. Because allergic rhinitis has early- and late-phase reactions, therapy must be directed toward control of both responses. There are a number of types of urticaria; therapy for each may vary.

Antihistamines and decongestants.

Drug therapy for allergic rhinitis is used either to prevent symptoms from occurring by short-circuiting the reaction and thus inhibiting the production of chemical mediators or to control symptoms after the target organs have been stimulated by these mediators. Antihistamines, the mainstay treatment of allergic rhinitis, are H1-receptor antagonists that bind competitively to histamine receptors. The older, classic antihistamines are effective in treating the symptoms of allergic rhinitis, but most are sedating because they cross the blood-brain barrier. They also have anticholinergic activity, which further restricts their use. The new, nonsedating antihistamines have overcome most of these limitations, and because they are long-acting, they require fewer daily dosages. Many still under development are quite potent and may be used for indications other than allergic rhinitis. Decongestants, sympathomimetic amines, are available both orally and topically as either short- or long-acting preparations. Topical decongestants should be used only for a short time to prevent rebound and ensuring overusage. These drugs interact with numerous antihypertensive medications and tricyclic antidepressants. Often combined with antihistamines, decongestants help offset their sedative effect.

Pharmacology of upper respiratory allergy.

Patients with upper respiratory allergy may benefit from the use of many pharmacologic products. Using the simplest form of therapy that will relieve the problem is usually both clinically efficacious and cost efficient. Understanding the indications, benefits, and potential adverse effects of each group of drugs, particularly the classic and new antihistamines, decongestants, intranasal and systemic corticosteroids, and mast cell stabilizers (such as cromolyn) will provide direction for the best total patient care.