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Biomedical subjects

J L Sanders

Publications and source records attributed to J L Sanders.

At least 37 records · Page 2Linked to original sources

Comparison of the adaptation of acrylic resin cured by microwave energy and conventional water bath.

Acrylic resin record bases made from three commercial resins were processed by water bath curing and by microwave energy. The adaptation of the record bases to a standard cast was measured to determine if there were any statistically significant differences in the fit that could be attributed to the differences in curing methods and the brands of resin. The results indicated a small statistically significant difference in favor of the water bath cure overall, but clinically there were no appreciable differences in the adaptation of the record bases with either curing method or the resins used. The adaptation of artificial dentures made from acrylic resin is clinically acceptable with either microwave curing or the water bath method.

Acrylic Resins↗

The use of microwave energy for processing acrylic resins.

Test strips of five different resins were processed with (1) microwaves by using a kitchen-type microwave oven, and (2) a conventional water bath. The strips were tested for hardness, porosity, and transverse strength. The results showed no significant difference between resin strips cured by either method. Maxillary dentures were waxed on stone casts of an aluminum model in another study. The dentures were processed with the same five resins, half by using microwave energy and the remainder with the water bath. The adaptation of the processed dentures to the aluminum cast was measured with feeler gauges. The results showed no statistically significant differences between dentures cured by either method. These studies demonstrated that the important physical characteristics of microwave-cured resin are approximately the same as resin cured in a conventional water bath. Curing dentures by microwave energy has the advantages of reduced curing time, ease, and cleanliness.

Acrylic Resins↗

A population dynamics simulation model with application to health planning.

Despite the increasing emphasis on computers and quantitative methods in health services programs, health services administration students are denied access to many of the most powerful tools of systems analysis, including discrete event simulation, because they lack the necessary background in computer programming, simulation methodology, and stochastic processes. This article presents an approach to the modeling of the growth and decline of population groups and their attributes that can be used by students who do not have the extensive quantitative background required to develop the usual discrete event simulation models. The underlying theory, which is based on the behavior of the expectation process of vector Galton-Watson branching processes, can be explained quite easily. An example is presented that uses an age and sex specific model of population growth to investigate policy questions related to the feasibility of the construction of a long-term care facility for a defined population group. Planning decisions are based on the growth and decline of the numbers of individuals in the various age and sex groups. Extensions of the basic methodology are possible that would include projections of the variance-covariance matrix of the population sizes for each year of the projection process. In addition, the model can be extended to include projections of the impact of infectious and communicable diseases on a defined population group together with the effect of categorical disease screening and control programs. Given the basic data utilized in the model, the implementation of the calculations required by the model can be made on modern microcomputer hardware using any of the standard spreadsheet programs.

Health Planning↗

Results of a survey of complete denture procedures taught in American and Canadian dental schools: an update.

Dental educators carry a heavy burden of responsibility. Principles and procedures are usually deeply inculcated in students by their teachers, which has a wide-spread effect on the future of dentists and patients. Prosthodontic treatment of edentulous patients, like any other branch of art and science, is not static; but viable, moving, and improving. Constant reevaluation of current and future programs should be made by all teachers who are responsible for prosthodontic education.

Canada↗

A photoelastic study of a split palatal major connector.

A study was made to determine if the split palatal design of maxillary major connectors used on distal-extension removable partial dentures would result in a reduction of torquing stresses on the abutment teeth when the bases were loaded. A photoelastic model to simulate the maxillary arch, abutment teeth with their periodontal ligaments, edentulous ridges, and mucoperiosteum of the palate and ridges was constructed. Two Kennedy Class II removable partial denture frameworks of chrome-nickel alloy were constructed to fit the photoelastic model. One framework had an intact palatal major connector, and the other had a split in the major connector to separate the base from the abutment tooth as a stress-breaker. The frameworks were placed on the model, loaded, and photographed with polarized light to record the stress pattern in the model. The results of this study showed that the split palatal major connector did reduce the stress delivered to the distal-extension abutment when the base was loaded on the experimental model. A significant amount of stress from loading of the framework was removed from the abutment tooth and transferred to the regions of the model underlying the base.

Acrylic Resins↗

Technical aspects of the Staphylococcus aureus teichoic acid antibody assay: gel diffusion and counterimmunoelecrophoretic assays, antigen preparation, antigen selection, concentration effects, and cross-reactions with other organisms.

Because variable results are being reported from laboratories performing the teichoic acid antibody assay in patients with serious infections due to Staphylococcus aureus, we have thoroughly reviewed all technical aspects of the test. This paper reports on the importance of agar and antigen preparation in standardizing results of the assay and reducing the prevalence of false-negative and -positive tests. Once standardized, the counterimmunoelectrophoretic method is as accurate as the gel diffusion method for both initial screening and generating titers; practically, however, unless numerous tests are to be performed, the gel diffusion technique will suffice for most purposes. The cell wall of the Lafferty strain of S. aureus was used as the standard antigen in assays for serum antibodies. We studied whether it is an appropriate antigen and found that antibody titers obtained with the Lafferty strain antigen were, in three patients with endocarditis, the same as those obtained with antigens from the individual blood stream isolates. We have also confirmed that pooled human gamma globulin can be used, by back titration against newly prepared lots of antigen, to select optimal antigen concentration and is as good as more specific, higher titer serum specimens for that purpose. Finally, cell wall antigens from Staphylococcus epidermidis and a variety of streptococci may react with normal human sera, but such antigens are distinct by immunoprecipitation from those from S. aureus.

Antibodies, Bacterial↗

Enzymic determination of cholesterol in serum lipoproteins separated by electrophoresis.

We describe a reliable, straightforward procedure for measuring the cholesterol content of serum lipoproteins separated by electrophoresis on cellulose acetate. The lipoprotein fractions are made visible by use of an enzymic reagent and then quantitated by densitometry. Standard electrophoresis equipment is used and the procedure requires just over 1 h for completion. All major fractions except chylomicrons are detected readily. Accuracy and precision agree favorably with results reported for generally accepted methods. Concentration and color development are linearly related to cholesterol concentrations up to 1.5 g/liter in a given lipoprotein fraction. We recommend this method for use in assessing high-density lipoprotein cholesterol and as an aid in lipoprotein phenotyping.

Cholesterol↗

Relation of personal space to the human menstrual cycle.

A behavioral measure of personal space was obtained from 84 female undergraduates who had completed a menstrual cycle questionnaire. They ranged in age from 17 to 27 years, with a mean age of 19.2 years. A significant relationship between personal space and the female's menstrual cycle was found. The personal space zone tended to be larger during the menstruous flow than during the approximate middle of the cycle. Results were discussed in the context of sexual responsiveness.

Adolescent↗

The relationship of dogmatism to the nonrecognition of perceptual ambiguity.

The relationship between dogmatism and the nonrecognition of perceptual ambiguity was investigated in 84 male and female colloge students. Significant but small nagative correlations were found between Rokeach's Dogmatism scale and two indicators of perceptual ambiguity: Necker cube perspective reversals and binocular retinal rivalry alternations in dominance. The nonrecognition of perceptual ambiguity was discussed within a psychoanalytic ego defense framework.

Adolescent↗

Personality correlates of the abstract response on the Holtzman Inkblot Technique.

Through the innovative use of a special set of Holtzman inkblots, several variables of the Personality Research Form were shown to be correlates of the Abstract response for 30 male and 33 female undergraduates. For males, positive correlations were obtained between Abstract and Achievement, Endurance and Sentience; while negative correlations were obtained between Abstract and Harmavoidance and Order, respectively. For females, Abstract was positively correlated with Dominance, Nurturance, Exhibition, and Social Recognition; and negatively correlated with Abasement and Affiliation.

Achievement↗

The further heterogeneity of creatine kinase. Presence of isoenzymes of cathodic mobility in rat tissues.

Supernatant fractions from rat tissue homogenates were examined for creatine kinase (EC 2.7.3.2) isoenzymes by agarose gel electrophoresis at pH 8.6. The distribution of the various isoenzymes, and their relative contributions to the total tissue creatine kinase, is stated. A previously unreported isoenzyme associated with brain and kidney preparations is described. It is a minor contributor to brain creatine-kinase activity but is the major isoenzyme for kidney. The presence of an additional isoenzyme for cardiac tissue was confirmed; this isoenzyme exhibits similar levels of activity to that of the MB isoenzyme.

Animals↗