This report describes a dual-beam, high-speed sorter (HiSS) with a droplet production rate of 220,000 s-1 now in routine use at the Lawrence Livermore National Laboratory. The system can process and sort objects at rates in excess of 20,000 s-1. We report here on the development of HiSS, describe its operational characteristics, and evaluate its utility for analysis and purification of human chromosomes, human erythrocytes, and living Chinese hamster ovary cells.

Cell Separation↗

PubMed1984

Three-dimensional response of a lumped parameter head-neck model due to impact and impulsive loading.

A numerical procedure developed previously for predicting sagittal-plane motion of the human head-neck system due to impact and impulsive loading has been extended to three dimensions. In both situations, a lumped parameter approach is employed, but the current model lumps the mechanical response of each intervertebral joint into a single force-deformation relation evaluated from mechanical properties assembled by various investigators. Computations were performed to obtain the response of the model to a two-dimensional case of flexion whiplash, to one three-dimensional case of side impact to the skull and to another involving base acceleration normal to the sagittal plane. Agreement of the kinematic variables with the results of both the previous two-dimensional analysis and experimental data from a volunteer run is satisfactory, but somewhat poorer correspondence was found for the three-dimensional predictions upon comparison with data obtained from a physical model and from a volunteer when subjected to the prescribed loading. The differences in response are attributed to higher stiffness of facet separation of the model relative both to the structure and the volunteer, to insufficient damping, as well as to substantial differences in the mechanical deformation characteristic of the components of the prototypes and the numerical model.

Atlanto-Axial Joint↗

PubMed1983

Use of quantitative analysis of urine to assess exposure to asbestos fibers in drinking water in the Puget Sound region.

An earlier epidemiologic and electron microscopy study of drinking water in the Everett area of Washington State indicated large numbers of naturally occurring chrysotile asbestos fibers in the water. The purpose of the present study was to determine whether significant numbers of asbestos fiber could be demonstrated in the urine of donors residing in that area for less than 3 yr and over 20 yr where the tapwater contained about 200 X 10(6) fibers/L. A control group was obtained from Seattle where the tapwater asbestos fiber content was 100 times less. Urine samples, filtered control water, tapwater samples, and additional controls were processed for transmission electron microscopy by the use of the Nuclepore membrane filter-Jaffe wick procedure. Interference by mucus in the urine was reduced by treatment with hydrogen peroxide. Samples were taken over a period of 21 months. At no time during this period did the asbestos content of the urine samples consistently exceed that of the control waters. There was a significant difference (p less than 0.05) in the asbestos content of urine samples from subjects with less than 3 yr residence times versus greater than 20 yr. Asbestos concentration in urine samples from Everett residents as a whole did not differ significantly from that in samples from Seattle residents. Variable degrees of chrysotile contamination of control water samples and of Nuclepore membrane filters presented a problem. At present, the data are inconclusive but would suggest no relationship between high concentrations of fibers in drinking water and the numbers estimated for voided urine.

Adult↗

PubMed1978

Computed tomography: planning, programming, budgeting.

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Air Conditioning↗

PubMed1969

Alveolar cell carcinoma. An electron microscopic study.

Explore the source record for details and available documents.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMedDate not supplied

Grand rounds: first metatarsophalangeal joint replacement.

For approximately 30 years foot and ankle surgeons have been using a variety of techniques and devices to replace the first metatarsophalangeal joint. During this time there have been a multitude of implant designs and modifications, most attempting to anatomically and functionally replace the natural joint surfaces. The advantages and disadvantages of these many designs and various biomaterials has long been debated in scientific meetings and publications. Surgical technique, implant design, materials, and patient selection remain areas of heated debate and ongoing research. With this in mind, we asked leading foot and ankle surgeons to give their opinions on indications and utilization for joint replacement of the first metatarsophalangeal joint.

Humans↗