Biomedical subjects

J H Weaver

Publications and source records attributed to J H Weaver.

11 recordsLinked to original sources

PubMed2002

Tunneling electron induced bromine hopping on Si(100)-(2 x 1).

Tunneling electrons from the tip of a scanning tunneling microscope can be used to induce adatom hopping on Br-terminated Si(100)-(2x1) at low current and without voltage pulses. Hopping does not occur when electrons tunnel from a sample to a tip. The threshold energy is +0.8 V, and tunneling spectroscopy shows antibonding Si-Br states 0.8 eV above the Fermi level. Electron capture in these states is a necessary condition for hopping, but repulsive adsorbate interactions that lower the activation barrier are also required. Such interactions are strong near saturation for Br but are insufficient when the coverage is low or when Br is replaced by Cl.

Journal Article↗

PubMed2002

Surface modification without desorption: recycling of Cl on Si(100)-(2 x 1).

We demonstrate chlorine-induced modification of Si(100)-(2 x 1) under conditions where Cl is recycled rather than desorbed as SiCl2. A dimer with 2 Cl atoms, 2SiCl, converts to SiCl2+Si, allowing the bare Si atom to escape onto the terrace. At temperatures below the desorption threshold, the SiCl2 unit decays through Cl diffusion, allowing the second Si atom to escape. The result is a dimer vacancy, terrace regrowth structures, and Cl that is able to participate in another pitting event. Access to this unexpected roughening pathway is controlled by the Cl concentration and temperature. This previously overlooked process represents an important component of Si(100) surface processing.

Journal Article↗

PubMed1983

An outbreak of acute hemorrhagic conjunctivitis in central Minnesota.

The only confirmed outbreak of acute hemorrhagic conjunctivitis in the continental United States during 1982 occurred in Brainerd, Minnesota. The disease first appeared in a 27-year-old woman during a trip to Tahiti. The patient's two daughters (8 months old and 3 years old) developed mild conjunctivitis two days later. Although the symptoms of all three had completely resolved before they arrived in Brainerd, illness compatible with acute hemorrhagic conjunctivitis developed in five other individuals who shared a house with them there. Symptoms appeared within two days in four of the five and within three days in the fifth. All five had high neutralizing antibody titers to enterovirus 70 (1:128, 1:32, 1:32, 1:128, and 1:256) and one had high antibody titers to coxsackievirus A24 which may cause similar symptoms (less than 1:4 in all cases). The symptoms resolved without sequelae in all five patients within five days. These cases demonstrated that a person who is no longer symptomatic can still infect others and that an infected person can transmit enterovirus 70 for at least eight days after the onset of symptoms.

Acute Disease↗

PubMed1981

Monitoring hearing loss at United Airlines.

The airlines are a highly diversified industry. Their major concerns are in the safe transportation of passengers and cargo with on time arrival and departure of its aircraft at various locations throughout the world. The challenge the airlines face is in the development and administration of an effective hearing conservation program that will produce valid audiometry at all of its logistic operations and yet be economically feasible and practical. The methods and techniques used by United Airlines to develop and administer an effective hearing conservation program are presented here. Guidelines employing the OSHA Noise Exposure Standard were incorporated in the program requirements as set forth by the medical department.

Aircraft↗

PubMed1973