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Biomedical subjects

E E Campbell

Publications and source records attributed to E E Campbell.

At least 19 recordsLinked to original sources
PubMed2001

Excitation of Rydberg series in C60.

Rydberg series of C60 are reported for the first time. The Rydberg states are seen in photoelectron spectra using ultrashort pulsed-laser excitation, where the excited states formed are ionized with one further photon from the same laser pulse. The structure is observed for pulse durations as short as 100 fs with indications of residual structure for even shorter pulse excitation. The production mechanism is discussed and the Rydberg states are modeled by analytically solving the Schrödinger equation with a simple jelliumlike potential for C60.

Journal Article↗
PubMed2000

Delayed ionization and fragmentation en route to thermionic emission: statistics and dynamics.

Thermionic emission is discussed as a long time (microseconds) decay mode of energy-rich large molecules, metallic and metcar clusters, and fullerenes. We review what is known and consider the many experiments, systems, and theoretical and computational studies that still need to be done. We conclude with a wish list for future work. Particular attention is given to the experimental signatures, such as the dependence on the mode of energy acquisition, and theoretical indications of a not-quite-statistical delayed ionization and to the competition of electron emission with other decay modes, such as fragmentation or radiative cooling. Coupling of the electronic and nuclear modes can be a bottleneck and quite long time-delayed ionization can be observed, as in the decay of high Rydberg states probed by ZEKE spectroscopy, before the onset of complete energy partitioning.

Journal Article↗
PubMed1990

Homograft tympanoplasty: a long-term review of 477 ears.

Homograft materials have been employed to reconstruct the tympanic membrane and ossicular chain since the mid-1960s. Although the use of homograft materials remains somewhat controversial, this technique has been shown to provide excellent long-term results, both anatomically and functionally. This study reports on the long-term results of 477 ears undergoing homograft tympanoplasty and the modification of previously reported surgical techniques.

Audiometry↗
PubMed1988

Smoking cessation counseling by resident physicians in internal medicine, family practice, and pediatrics.

Residents in primary care specialties care for many patients who smoke cigarettes, but little is known about their smoking cessation counseling (SCC). We surveyed 309 residents (72 family practice, 171 internal medicine, and 66 pediatrics residents) in 13 programs to determine their practices, knowledge, attitudes, and training in SCC. More than 90% thought physicians are responsible for SCC, the majority routinely took smoking histories, and 80% attempted to motivate patients to quit smoking. However, 25% or fewer reported discussing obstacles to quitting, setting a quit date, prescribing nicotine gum, scheduling follow-up visits, or providing self-help materials. Family practice residents used more SCC techniques (1.8) than did internal medicine (0.8) and pediatrics (0.1) residents. Only 54% of residents reported recent SCC training and 13% reported formal SCC training. Recent training correlated with the number of counseling techniques used. Residents in primary care specialties report positive attitudes but inadequate practice and training in SCC.

Attitude of Health Personnel↗
PubMed1983

Venous thrombosis in a family with defective release of vascular plasminogen activator and elevated plasma factor VIII/von Willebrand's factor.

A family is described in which venous thrombosis developed in five members as early as 14 years of age. Routine coagulation studies, plasma antithrombin III, factor V, plasminogen, beta-thromboglobulin, fibrinopeptide A, prothrombin fragment F1+2, and thrombin-antithrombin III complex were all within normal limits. However, defective release of vascular plasminogen activator was observed on several occasions in all five subjects as compared with a control population of 125 persons (0.04 Committee on Thrombolytic Agents [CTA] units/ml plasma as compared with 0.21 CTS units/ml). In addition, levels of factor VII/von Willebrand's factor were significantly elevated above the normal range in this pedigree.

Adolescent↗
PubMed1982

A colorimetric assay for releasable plasminogen activator.

We describe an equilibrium assay for measuring release of plasminogen activator form blood-vessel walls and report data from 125 individuals free of overt thromboembolic disease. Excess human plasminogen is added to the euglobulin fraction of plasma obtained before and after venous occlusion at mean systolic pressure. To measure plasmin generation in these samples, we used the chromogenic plasmin substrate D-Val-Leu-Lys-p-nitroanilide, which liberates p-nitroaniline upon cleavage. Releasable plasminogen activator in 24 subjects was determined by this colorimetric assay and by the radiocasein assay previously reported by this laboratory (Am. J. Clin. Pathol. 76,403-409, 1981), and the results were compared. The correlation coefficient was 0.97. The colorimetric assay offers several advantages over the radiocasein assay: shorter incubation (6 vs 16 h) and no preparation or quantification of a radioactive substrate and its cleavage products.

Adult↗
PubMed1981

Fibrinolytic response and oral contraceptive associated thromboembolism.

A case-control study of fibrinolytic activity was conducted comparing 12 women with a recent history of thromboembolism while taking oral contraceptives and 28 matched female controls without a history of thromboembolism. All subjects had stopped using oral contraceptives at least 12 months prior to study. A new assay, recently developed in this laboratory, was used to evaluate the mean fibrinolytic response to venous occlusion in both cases and controls. The fibrinolytic response of all subjects was stratified into quartiles as previously described. While the controls segregated as expected, all 12 cases occurred in subjects whose fibrinolytic response fell in the first two quartiles with 8 of the 12 subjects having first quartile responses. The mean fibrinolytic response for all controls was 12.3 units while cases showed a mean response of only 3.9 units. The above data supports and extends our recent suggestion that low fibrinolytic response may signal a natural predisposition to venous thromboembolism which could be triggered by use of synthetic estrogens. However, these data do not support the use of this assay as a screening test for oral contraceptive related risk to thromboembolism since at least 50% of the control population also segregate in the first two quarters.

Caseins↗
PubMed1978

Tympanoplasty using homograft tympanic membranes and ossicles.

The use of homograft materials in reconstructive, mastoid, and middle ear surgery is increasing. Not only are they useful and practical, but they also do the job well in both anatomical and functional restoration. Many encouraging reports have been written to support their use. Their advantages, in the opinion of the author, outweigh their cost since they can offer a more efficient, versatile, and better method of restoration of hearing in tympanoplasty surgery.

Ear Ossicles↗
PubMed1976

The interpretation and applicati-n of OSHA carcinogen standards for laboratory operations.

A safety protocol implemented at the Los Alamos Scientific Laboratory for a project involving 14 chemical carcinogens is described. Specific topics pertaining to facilities, personnel practice, laboratory operations, decontamination and disposal are discussed within the context of regulations issued by the Occupational Safety and Health Administration.

Accident Prevention↗