Asymmetries in core-collapse supernovae from maps of radioactive 44Ti in Cassiopeia A.

Asymmetry is required by most numerical simulations of stellar core-collapse explosions, but the form it takes differs significantly among models. The spatial distribution of radioactive (44)Ti, synthesized in an exploding star near the boundary between material falling back onto the collapsing core and that ejected into the surrounding medium, directly probes the explosion asymmetries. Cassiopeia A is a young, nearby, core-collapse remnant from which (44)Ti emission has previously been detected but not imaged. Asymmetries in the explosion have been indirectly inferred from a high ratio of observed (44)Ti emission to estimated (56)Ni emission, from optical light echoes, and from jet-like features seen in the X-ray and optical ejecta. Here we report spatial maps and spectral properties of the (44)Ti in Cassiopeia A. This may explain the unexpected lack of correlation between the (44)Ti and iron X-ray emission, the latter being visible only in shock-heated material. The observed spatial distribution rules out symmetric explosions even with a high level of convective mixing, as well as highly asymmetric bipolar explosions resulting from a fast-rotating progenitor. Instead, these observations provide strong evidence for the development of low-mode convective instabilities in core-collapse supernovae.

Cephalometric evaluation of the changes in patients wearing complete dentures: a 20-year study.

The purpose of this continuing longitudinal investigation was to study the changes on the craniofacial complex in complete denture wearers; herein are reported the 20-year findings. At the onset of the study complete dentures were made for 64 persons. Two dentures techniques were employed: a complex method of construction and a simplified method. At the start of the project the patients' ages ranged from 30 to 60 years (average age 53 years) and all had been edentulous for at least 1 year (range 1 to 30 years). Lateral cephalometric radiographs were made immediately after initial placement of the dentures and during subsequent years (1, 2, 3, 4, 5, 7, 10, 15, and 20). The same cephalostat was used throughout and all films were exposed with the teeth in centric occlusion. Thirty-four subjects presented for the 20-year follow-up. Of this number, the radiographs of 24 subjects (14 women and 10 men; average age 65.5 years [range 50-83 years]) (12 complex denture wearers; 12 simplified technique denture wearers) were used in this report (10 had denture alterations over the 20-year period that excluded them). The 20-year observations corroborate earlier findings. There is a loss of the vertical dimension of occlusion as viewed from the right profile, and the mandible rotates in a counterclockwise fashion resulting in an increase in relative prognathism. The maxillary alveolus was stable, the mandibular alveolus resorbed, and the dentures rotated counterclockwise and shifted slightly forward. The observed changes were not significantly affected by the sex of the patient or by the denture technique employed.

An analysis of the effect of mandibular length on residual ridge loss in the edentulous patient.

The relationship of mandibular length to residual ridge loss was studied in 22 edentulous patients. Tracings made from cephalometric films taken at initial insertion of complete dentures and at 20 years after placement were measured. Mandibular length was determined to have no statistical relationship to the reduction in residual ridge height in either the maxillae or the mandible. In addition, alveolar bone loss in the one jaw had no relationship to the amount of loss in the other jaw.

An analysis of the relationship between mandibular alveolar bone loss and a low Frankfort-mandibular plane angle.

A group of complete denture patients was studied to determine the effect of a low Frankfort-mandibular plane angle on the loss of residual ridge height in the mandible. Measurements were made from tracings of cephalometric films. The low-FMA group did not experience statistically greater amounts of alveolar ridge loss when compared with the group with an FMA larger than 20 degrees. The loss of residual ridge height for both groups followed a linear relationship from year 5 to year 20. There was some indication that the residual ridge height was smaller initially in the low-FMA group. The relative effect of the loss of residual ridge height, combined with smaller residual ridge height originally, indicates that the low-FMA patients are more likely to have anatomic deficiencies and problems with complete dentures associated with this lack of mandibular residual ridge height.

Patient response to variations in denture technique. Part VII: Twenty-year patient status.

Sixty-four patients were originally treated with complete dentures. Two different techniques, complex and standard, were used with 32 patients assigned to each group. Patients were recalled for their 20th year recall and 34 of the original 64 patients returned. Of those 34 patients, 26 patients were still wearing their original dentures. All 26 patients were judged by three project clinicians to have clinically acceptable dentures. In addition, all but two stated that their dentures were clinically acceptable. Neither of these patients were unhappy with fit, but with the esthetics. One patient had worn his denture teeth by pipe smoking and the other had bleached the pink out of her denture bases. The remaining eight patients who still participate in the project have had modifications in their original dentures or have had new dentures constructed.

[The action of phenylmercuriacetate and nitrate in combined application in rats: the thyroid gland, liver enzymes and morphologic findings in the brain and kidney]. / Zur Wirkung von Phenylquecksilberacetat und Nitrat bei kombinierter Verabreichung an Ratten: Schilddrüse, Enzyme der Leber, morphologische Befunde an Gehirn und Nieren.

Rats were exposed to nitrate (NO3-) in drinking water, to phenylmercuryacetate (PMA) by gavage and to NO3- and PMA together during 4 different experiments. PMA impaired kidneys, NO3- thyroid gland, and NO3- and PMA together both organs. In the last case a synergistic effect on the thyroid gland was shown. The lowest effective concentration of NO3- was 40 mg/l. It resulted in histomorphological changes of the thyroid epithelial cells. That low effective dose of NO3- and possible synergistic effects should give a further impulse to take into consideration not only a low iodide intake but also goitrogenic environmental chemicals when evaluating the endemic goitre prevalence.

[Hematologic changes in rats following exposure to dichlorvos]. / Hämatologische Veränderungen an Ratten nach Dichlorvosexposition.

Two different experiments on rats were carried out: an acute intoxication causing clinical symptoms and a subchronical intoxication without any symptoms. After the acute experiment an increase of hemoglobin- and hematocrite values as well as of the mean corpuscular hemoglobin concentration was found. These differences are interpreted to be an increased erythropoiesis after hypoxia. Following the subchronical experiment the parameters mentioned above had decreased. These results linked up to anisocytosis, poikilocytosis and/or polychromasia in 30% of the treated animals and allow to assume a disorder of erythropoiesis. The results require to take in consideration a prophylactic hematological survey of long-term exposed people.

Enzyme activities after in vitro and in vivo application of dichlorvos.

The pesticide dichlorvos inhibits not only cholinesterase but also alkaline phosphatase, lactate dehydrogenase and glutamate dehydrogenase competitively. A mixed type inhibition of glutamic-oxaloacetic transaminase is in contrast to the increased activity of glutamic-pyruvic transaminase after dichlorvos application. The activity of leucine aminopeptidase is not affected by the substance. After administering rats an acutely toxic dose of dichlorvos (70 mg per kg b.w.) in vitro-inhibitions other than that of cholinesterase could not be found.

Patient response to variations in denture techniques. Part VI: Mastication of peanuts and carrots.

This 5-year study was designed to determine if differences in masticatory ability existed among patients for whom dentures had been prepared with two different techniques. Patients were instructed to chew a given amount of a reliable test food for a certain number of strokes on each side of the mouth. After each trial the food was collected into a No. 8 mesh screen, washed, dried, and weighed. The percentage weight of food masticated per side per patient was recorded for each year. Results were combined for each group results and analyzed statistically. Statistical analysis of the two groups revealed changes in masticatory ability over the 5-year period. However, no significant statistical differences in masticatory ability existed between the two groups.

Cephalometric evaluation of the changes in patients wearing complete dentures. A ten-year longitudinal study.

This study analyzed the longitudinal cephalometric head films of 37 edentulous patients over a 10-year period. The purpose of the investigation was to document changes within the craniofacial complex, residual ridge resorption, and position of the dentures. The changes were correlated with the following variables: age, sex, skeletal pattern, number of years edentulous, technique of denture fabrication, and nighttime wear of the dentures. Findings in this study suggest the following. The maxillae and the mandible showed sagittal spatial counterclockwise displacement. Complete dentures exhibit a counterclockwise rotation and forward movement. Soft tissue seating is more important than alveolar ridge resorption in the positional changes of complete dentures. Variation in denture techniques had no influence on the observed changes. Artificial porcelain teeth did not show a measurable amount of attrition during the 10-year observation period. Observed changes were not significantly affected by variables such as sex, years edentulous, nighttime wear, or skeletal pattern. Two exceptions were that the skeletal pattern affects prognathism and number of years edentulous affects mandibular ridge resorption.

[Spectrophotometric evaluation of hemolysis tests]. / Zur spektrophotometrischen Auswertung des Hämolysetestes.

A quantitative spectrophotometric method for measuring the hemolysis degree of PVC-biomaterials by potassium hexacyanoferrate (III) and potassium cyanide is presented. By means of this method the physiological valuation of biomaterials proved more exact as to their contents of hemolytically acting substances. In order to define the maximum permissible degree of hemolysis from biomaterials further studies will be necessary. UV- and IR spectrograms of the 70 degrees C and 121 degrees C extracts from biomaterials indicated the presence of substances not yet identified till now. These substances couldn't be ascribed any specific biological effects. An extraction at 121 degrees C is recommended in order to detect hemolytically acting substances.

Patient response to variations in denture technique. Part V: Microscopic response of the oral mucosa.

The purpose of this study was to determine the effects of two different denture construction techniques on the maturation of the oral mucosa. Complete maxillary and mandibular dentures were constructed for 64 patients. Half of the subjects received dentures fabricated by a complex technique, and the remaining subjects received dentures fabricated by a standard technique. Cytologic smears were made from four regions of the denture-bearing mucosa at yearly intervals for 5 years following construction of the dentures. The smears were stained by the Papanicolaou technique. Microscopic analysis based on cytologic characteristic revealed no discernible difference between the mucosa of those subjects with dentures constructed via the complex technique and that of those with dentures constructed via the standard technique.

Patient response to variations in denture technique. Part III: Five-year subjective evaluation.

Dentures were constructed for 64 patients by two different techniques. One technique, designated as "complex," involved more complicated procedures such as a true hinge axis location, balanced occlusion, dentures remounted on an articulator after processing with new interocclusal records, and occlusal corrections made on the articulator. The "standard" technique involved an arbitrary mounting of the maxillary cast on the articulator, arranging the occlusion with centric relation coincident with centric occlusion but without a balanced occlusion, and making occlusal corrections in the mouth. Subjective evaluations were made for each of the 64 patients at initial placement of the dentures and for all active patients at five yearly recall visits following placement. The evaluation method was designed to determine clinical differences between the dentures made by the two techniques. At the end of 5 years, the data obtained at five yearly recall visits were subjected to statistical testing. These tests were performed to determine if the technique by which the dentures were made had any effect on the performance of the dentures that could be detected clinically. The results of the test showed that there was no significant difference between dentures made using two denture techniques that could be detected by subjective means.

Patient response to variations in denture technique. Part II: five-year cephalometric evaluation.

This study was designed to determine if differences in rates of residual alveolar bone loss could be found in patients wearing dentures made by a complex technique and a standard technique. Cephalometric radiographs were made for each of 64 patients at initial placement of the dentures and for all active patients at five yearly recall visits. These radiographs were measured to determine rates of mandibular bone loss, maxillary bone loss, loss of total face height, rotation of the mandible, and migration of the denture bases over the 5-year period. At the end of the study no statistically significant differences between the two groups of patients could be found. Examination of all participants in this study revealed rates of bone loss that were very similar to those reported by other investigators.