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Biomedical subjects

B Haller

Publications and source records attributed to B Haller.

36 records · Page 2Linked to original sources
PubMed1990

[Shear bond strength between composite inlay and luting composite resin].

The shear bond strength between composite inlay materials and luting composite resins was measured under different storage conditions and using different finishing techniques. The initial shear bond strength was distinctly higher with light-cured composites subjected to secondary light and heat cure (56.7-81.1 MPa) than with a heat- and pressure-cured material, where appreciable bond strength was achieved only after sandblasting of the composite surface (18.8 MPa). In general, water storage of the samples for 30 days with intermittent thermocycling adversely affected the bond strength. The influence of secondary light and heat curing on the bond strength of primarily light-cured composites was highly dependent on the material used.

Composite Resins↗
PubMed1990

[Marginal seal of cervical composite inlays in vitro].

The presence of microleakage at the dentinal margins of conventional Class V restorations and direct composite inlays in combination with four dentin bonding agents was assessed by means of dye penetration. The use of dentinal adhesives with conventional one-step composite fillings failed to prevent marginal leakage. The dentin bonding agents used in this study were for more efficient when used with direct composite inlays. The resistance to thermal stress of these bonded Class V composite inlays was improved by application of a secondary light and heat cure, probably due to relaxation of residual material stress.

Acid Etching, Dental↗
PubMed1989

[Technology and progress in conservative dentistry].

In a synopsis different possibilities for the use of tooth colored restorations as replacements for amalgam fillings are described and discussed: composite resin fillings, indirect or direct composite resin and ceramic inlays.

Composite Resins↗
PubMed1989

[Influence of die spacer on the marginal gap of partial crowns].

The effect of die spacer in the fabrication of partial crowns was examined in an in vitro study. Even with good overall expansion of the investment material it is impossible to prevent tight spots in the areas of the box form or clasp retentions. These have to be removed by grinding. Accurate application of die spacer may improve the marginal fit significantly while reducing the amount of grinding necessary.

Crowns↗
PubMed1988

Replacement of the macronuclear ribosomal RNA genes of a mutant Tetrahymena using electroporation.

The macronucleus of the ciliate Tetrahymena contains approx. 10(4) ribosomal RNA gene molecules (rDNA) in the form of linear, autonomously replicating palindromes. Previous studies have shown that macronuclear rDNA molecules derived from wild-type (wt) inbred strain C3 out-replicate those derived from wt inbred strain B, in macronuclei initially heterozygous for both, leading to the complete loss of the B rDNA. However, rmm-1, a cis-acting laboratory-induced mutation obtained previously by mutagenesis of inbred strain C3, causes the mutant rmm-1 rDNA to be completely out-replicated by B rDNA. These findings suggest the following hierarchy of replication potential: wt C3 greater than wt B greater than C3-rmm-1. We used electroporation to test whether cells containing only rmm-1 macronuclear rDNA are favorable recipients for transformation with either wt B or C3 donor rDNA molecules. The donor rDNA molecules carried the selectable marker Pmr (paromomycin resistance) located in the coding region of the 17S rRNA. Transformants were obtained, at a frequency greater than 1 in 10(5), by electroporation under a wide range of electrical discharge parameters. The fraction of cells surviving electroporation varied between 2 and greater than 95% in successful experiments. Replacement ('transplacement') of the recipient rDNA was observed, consistent with the prediction that B and C3 rDNA should out-replicate rmm-1 rDNA. These findings are also consistent with the previous conclusion that the differential replication determinants reside in the 5'-nontranscribed spacer of the rDNA.

Animals↗
PubMed1984

Accuracy of respiratory inductive plethysmograph over wide range of rib cage and abdominal compartmental contributions to tidal volume in normal subjects and in patients with chronic obstructive pulmonary disease.

We assessed the accuracy of the respiratory inductive plethysmograph in the supine position to spirometry by the two-body position, least squares calibration and single-body position, isovolume calibration procedures. The comparison was carried out simultaneously in normal subjects breathing naturally and with voluntarily controlled abdominal or thoracic breathing, and in patients with COPD breathing naturally and with voluntarily controlled abdominal breathing patterns. In both groups, there was no significant difference in estimation of tidal volume between the 2 calibration procedures for the various breathing patterns. There was greater deviation from spirometric tidal volume values for both calibration methods in patients with COPD during abdominal than during natural breathing. In the normal subjects, agreement between the rib cage and abdominal partitioning of tidal volume for both calibration methods was good, but in the patients with COPD there was greater variability. In normal subjects, over a wide range of rib cage and abdominal compartmental contributions to tidal volume, either calibration procedure appears satisfactory. For patients with COPD, if large changes occur in the distribution of rib cage and abdominal contributions to tidal volume, then validation of respiratory inductive plethysmography to spirometry must be rechecked.

Abdomen↗
PubMedDate not supplied

[Experimental statistical studies on the evaluation of the value of evidence in the comparison of human hair].

In this paper a statistical experiment is presented which allows to estimate the evidential value of human head hair comparison. The procedure described in detail was essentially the same as in case-work. Questioned hairs were taken randomly from 20 different persons out of a pool of 111 individuals. From each of the 20 persons one, three an five hairs respectively were compared consectively with samples from 100 different individuals. The results were classified as follows: a) "matching" and b) "similar" - if the hair(s) may originate form that person; c) "not matching" - if an individual is excluded as possible source. In our experiment about 95% of the samples (persons) were excluded as possible source of a questioned hair on the average. This is a mean value which may vary considerably in a distinct case. The experiment, its results and problems are discussed.

Adult↗