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Biomedical subjects

R Weinberg

Publications and source records attributed to R Weinberg.

At least 73 records · Page 4Linked to original sources
PubMed1984

Effects of solution depletion on films developed in the Peri-Pro automatic processor.

The changes in image quality and archival quality of dental films processed successively at room temperature in a Peri-Pro automatic processor without replenishment were measured. The changes in base-plus-fog density, film density and image contrast were measured for each of four processing solutions. All films to be developed in a solution were processed within 4 1/2 hours. The results cannot be generalized to solutions left overnight in the Peri-Pro processor or to solutions used in other automatic processors at different time-temperature cycles. If about 500 films are to be processed in a single day, the Peri-Pro solution, regular X-Omat, and RP X-Omat without part C are the solutions of choice. If about 1,000 films are to be processed in a single day, the Peri-Pro solution and RP X-Omat solution without part C are the solutions of choice. Only the Peri-Pro solution produced films (the first 600 films) of acceptable archival storage quality.

Radiographic Image Enhancement↗
PubMed1983

Effects of cyanoacrylates on die stone.

An evaluation was made of the effects of the application of an increasing number of coats of cyanoacrylate on die stone. The application of one coat of cyanoacrylate adhesive on the surface of trimmed and marked dies increases the surface hardness, increases the scratch resistance, will not change the dimensions of the die appreciably, and renders the margin marking more permanent. Excess resin should be removed immediately by compressed air. The use of hardener instead of water is recommended for mixing Type IV dental stone. Use of the cyanoacrylate method will aid the dentist and the technician in achieving an accurate crown fit.

Calcium Sulfate↗
PubMed1983

A test of the role of two oncogenes in inherited predisposition to colon cancer.

Inheritance of mutationally altered oncogenes could predispose individuals to the development of specific tumors and account for familial tumor phenotypes. Using adjacent DNA sequence polymorphisms as genetic markers, we have examined two oncogenes, the Kirsten ras2, isolated from a human colon cancer cell line, and the Harvey ras1, isolated from a human bladder cancer cell line, for their role in the genetic etiology of inherited colon cancer in Gardner syndrome. Both oncogene loci have been shown to be unlinked to the Gardner syndrome locus and are, therefore, eliminated as candidates for the Gardner syndrome gene.

Base Sequence↗
PubMed1982

Histologic typing of lung cancer in Louisiana.

To determine whether histologic patterns differed in the high- and low-lung cancer mortality parishes (counties) of Louisiana and whether the findings in the state differed from those in other parts of the United states, we studied the available histopathologic materials for 272 persons of the 815 who died of lung cancer in ten southern, nonurban Louisiana parishes during a seven-year period from 1971-1977. Squamous-cell carcinoma and small-cell anaplastic carcinoma were the most common tumor types, closely followed in frequency by adenocarcinoma, confirming reports by other investigators of a change during the past decade in the prevalence of various histopathologic types of lung cancer. The distribution of histopathologic types was not different for high- and low-mortality parishes but differed significantly from other areas of the U. S. Three persons had diagnoses consistent with pleural mesothelioma. Occupational histories obtained from relatives showed that one of those persons was a homemaker and the other two were sugarcane farmers with no discernable exposure to asbestos.

Adenocarcinoma↗
PubMed1982

Evaluation of contrast in duplicated radiographs.

This investigation evaluated changes in the contrast of duplicated radiographs made at different ultraviolet light exposures. Increasing ultraviolet light exposure had different effects on the duplicates of originals of different "background" densities. When correctly exposed, a duplicate radiograph enhanced contrast. When originals had the same contrast but different "background" densities, their duplicates did not have the same contrast. It was not possible to duplicate accurately all the different contrasts measured on an original. It was possible, however, to produce duplicates with all contrasts greater than those of the original.

Copying Processes↗
PubMed1982

Sensitometric comparison of dental films of groups D and E.

In early 1981 Kodak introduced into the market Ektaspeed dental film of speed group E, which is more sensitive than Ultra-Speed film of speed group D. This investigation compared the sensitometric properties of Kodak dental films of speed groups D and E. By plotting a graph of density against log relative exposure, the characteristic curves were drawn for the two types of films. The curves showed that film E was approximately twice as fast as film D. A table derived from a mathematical description of the characteristic curves permitted the formulation of exact exposure-multiplying factors for changing from one type of film to another. Both films had almost the same useful density range, but film D had higher average film contrast and lower latitude than film E.

Radiography, Dental↗