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At least 19 recordsLinked to original sources
PubMed1989

[Accuracy of complete dental arch impressions and stone casts using a three-dimensional measurement system. Effect on accuracy of rubber impression materials and trays].

The purpose of this study was to investigate and compare the accuracy of complete dental arch impressions and stone casts made from two kinds of impression materials (addition type silicone and polysulfide rubber) and trays (custom tray and modified custom tray). In addition, the effect of quantity of gypsum was examined. Impressions were made from a metallic model of a simplified maxillary dentition. Impressions and stone casts were measured respectively using the three-dimensional measuring microscope. The results were as follows: 1. Distortion of impressions was so small that the reproducibility of impressions was superior three-dimensionally. 2. These kinds of impressions and trays did not influence the accuracy of impressions but had an effect on the accuracy of the stone casts. 3. Generally, the setting expansion of gypsum in the impression occurred in all directions. 4. Arch widths and lengths on the stone casts tended to increase in number. 5. Stone casts made from an addition/type silicone impression material and a custom tray were the most accurate because the combination of the impression material and tray effectively suppressed the setting expansion of gypsum. 6. By controlling the quantity of gypsum, the accuracy of stone casts could be improved.

Dental Impression Materials↗
PubMed1990

Accuracy of complete dental arch impressions and stone casts using a three-dimensional measurement system. Effects on accuracy of rubber impression materials and trays.

The purpose of this study was to investigate and compare the accuracy of complete dental arch impressions and stone casts made with two kinds of impression materials (addition-type silicone and polysulfide rubber) and trays (custom tray and modified custom tray). In addition, the effect of the quantity of stone was examined. Impressions were made from a metallic model of a simplified maxillary dentition. Impressions and stone casts were measured respectively with a three-dimensional measuring microscope. The results were as follows: 1. Distortions of impressions were so small that the reproducibilities of impressions were superior three-dimensionally. These kinds of impressions and trays did not influence the accuracy of impressions. 2. The setting expansion of the stone in the impression occurred in the outward direction and was affected by the kinds of impressions and trays. 3. The arch widths and lengths of the stone casts tended to increase in number. 4. Stone casts made with addition-type silicone impression material and a custom tray were the most accurate because the combination of the impression material and tray effectively suppressed the setting expansion of stone. 5. The accuracy of stone casts could be improved by controlling the quantity of stone.

Calcium Sulfate↗
PubMed1991

Palpable masses in the prostate: superior accuracy of US-guided biopsy compared with accuracy of digitally guided biopsy.

The accuracies of digitally guided biopsy versus ultrasound (US)-guided biopsy of the prostate were compared in 112 consecutive men with palpable prostatic lesions who had previously undergone conventional digitally guided biopsy and in which the results were negative for carcinoma. US-guided biopsies were performed with either the transperineal (n = 51) or transrectal (n = 61) approach, by means of previously described methods. All US-guided biopsies were performed within 3 months after the most recent conventional biopsy. In 44 patients (39.3%) with negative results of conventional biopsies, the results of US-guided biopsy revealed cancer. The transrectal and transperineal digitally guided biopsies were equally inaccurate, and the transrectal and transperineal US-guided biopsies showed no statistically significant differences in accuracy. The patients accepted and tolerated both US techniques equally well; neither technique was associated with significant complications. It is concluded that all patients with a palpable nodule should undergo US-guided biopsy if the result of conventional digitally guided biopsy is negative for cancer and the diagnostic US scan suggests an abnormality.

Biopsy, Needle↗
PubMed1992

[Studies on dimensional accuracy of working casts made by various impression techniques--influence of undercuts on dimensional accuracy].

The purpose of this research was to evaluate the clinical acceptability of various impression techniques by comparing the dimensional accuracy of their working casts. An original metallic model was designed for this experiment. It has reference points to overlap and compare the master model and the working casts for measuring their dimensional accuracy under the same condition. The amount of distortion in each area of the working casts was examined by the measuring points within the model. The master model simulated an abutment for a full veneer crown with undercuts between the adjacent teeth. It was planned so that the amount of undercuts and distances between the adjacent teeth could be changed. As a result, a small distortion of the working casts due to the undercuts was observed by the technique using an individual tooth tray and polysulfide rubber base impression material. There was no significant dimensional change in the working casts made with silicone rubber base material. For the working casts made by hydrocolloid-alginate combination technique, the dimensional change was greater and distortion was observed in the abutment cast when the undercuts of the adjacent teeth were great. However, the distortion was less when the undercuts were small.

Dental Casting Technique↗
PubMed1985

Evolutionary aspects of accuracy of phenylalanyl-tRNA synthetase. Accuracy of the cytoplasmic and chloroplastic enzymes of a higher plant (Phaseolus vulgaris).

The phenylalanyl-tRNA synthetases from cytoplasm and chloroplasts of bean (Phaseolus vulgaris) leaves employ different strategies with respect to accuracy. The chloroplastic enzyme that is coded for by the nuclear genome follows the pathway of posttransfer proofreading, also characteristic for enzymes from eubacteria and cytoplasm and mitochondria of lower eukaryotic organisms. In contrast, the cytoplasmic enzyme uses pretransfer proofreading in the case of noncognate natural amino acids, characteristic for higher eukaryotic organisms and archaebacteria. Dependent on the nature of the noncognate amino acid, pretransfer proofreading in this case occurs without tRNA stimulation or with tRNA stimulated with no or little effect of the nonaccepting 3'-OH group of the terminal adenosine. The fundamental mechanistic difference in proofreading between the heterotopic intracellular isoenzymes of the plant cell supports the idea of the origin of the chloroplastic gene by gene transfer from a eubacterial endosymbiont to the nucleus. Origin by duplication of the nuclear gene, as indicated for mitochondrial phenylalanyl-tRNA synthetases [Gabius, H.-J., Engelhardt, R., Schroeder, F.R., & Cramer, F. (1983) Biochemistry 22, 5306-5315], appears unlikely. Further analyses of the ATP/PPi pyrophosphate exchange and aminoacylation of tRNAPhe-C-C-A(3'NH2), using 11 phenylalanine analogues, reveal intraspecies and interspecies variability of the architecture of the amino acid binding part within the active site.

Amino Acyl-tRNA Synthetases↗
PubMed2025

Construction and accuracy assessment of an efferocytosis-related prognostic model for ovarian cancer: A diagnostic accuracy study.

The study aimed to investigate the prognostic significance of efferocytosis-related genes in ovarian cancer (OC) with regard to cancer development, progression, invasion, and metastasis. OC cohorts were assembled from bioinformatics repositories. Utilizing consensus clustering analysis, distinct clusters were delineated based on the intersection of OC-related genes and efferocytosis-related genes. A prognostic signature specific to efferocytosis in OC was developed using data from The Cancer Genome Atlas, validated against the gene expression omnibus database, and subjected to independent prognostic analysis. Subsequently, a nomogram model was formulated. Moreover, investigations encompassed the immune microenvironment, immunotherapy, mutation profiling, drug sensitivity assessments, drug prediction models, and molecular docking analyses. Finally, quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays were employed to ascertain the mRNA expression levels of key genes. Five key genes, FCGBP, BTN3A3, WDR91, SLC25A45, and BTNL3, were identified as significantly associated with OC. Both datasets and qRT-PCR demonstrated elevated expression levels of FCGBP and WDR91 in OC. Notably, AFLATOXIN B1 exhibited strong binding affinity to SLC25A45, ciclopirox to BTN3A3, and irinotecan to WDR91. The risk score, age, and stage were identified as independent prognostic factors, with the nomogram displaying efficacy in predicting OC patient survival. Variations in the immune cell infiltration profiles, including naive B cells, and expression levels of 6 immune checkpoint genes, such as CTLA4, were notable. High tumor mutation burden scores were associated with improved survival outcomes. Additionally, significant differences in the IC50 values of 123 anticancer drugs were observed between the 2 risk groups. This findings of this study highlight the efficacy of the efferocytosis-associated risk model in predicting the survival outcomes of OC patients, thus providing a novel reference for prognostic prediction in OC patients.

Humans↗
PubMed1992

The contribution of constructional accuracy and organizational strategy to nonverbal recall in schizophrenia and chronic alcoholism.

The Rey-Osterrieth complex figure was used to assess the separate influences of the constructional accuracy and the organizational strategy employed while copying the figure on the later, incidental recall of the figure. We tested a model, which hypothesized that subjects who copied the main framework of the figure holistically would be more likely to achieve good copy accuracy scores and to reproduce the figure more accurately at recall than subjects who used a piecemeal approach during copy. Subjects included 68 detoxified, chronic alcoholics (ALC), 28 patients with schizophrenia (SZ), and 69 normal control subjects (NCS). The results showed that the ALC and the SZ groups, on average, had lower accuracy and strategy scores at copy than did the NCS group, and furthermore, that the combined contributions of copy accuracy and copy strategy accounted for group differences at recall. A path analysis revealed that, for all three groups, copy strategy had a significant direct effect on copy accuracy. Moreover, copy accuracy and copy strategy made independent contributions to recall accuracy within the ALC and NCS groups; by contrast, within the SZ group, copy strategy made an independent contribution to recall performance but copy accuracy did not. These results suggest that (1) organizational strategy can influence constructional accuracy at both copy and recall; (2) copy accuracy and strategy have the potential to influence recall independently; and (3) the recall deficit in ALC could be attributed to abnormalities in both accuracy and strategy at copy, whereas in SZ it could be attributed only to strategy abnormalities. The deficits observed on the complex figure test in the ALC and SZ were primarily nonmnemonic and were related to ability in figure construction and organizational strategy.

Adult↗
PubMed1990

Recognition accuracy with a voice-recognition system designed for anesthesia record keeping.

We tested on three occasions, with anesthetists as subjects, the accuracy of two voice-recognition systems designed for anesthetic record keeping. Initially, a prototype system was tested (10 subjects); several years later the resulting commercial system was tested in a quiet environment (11 subjects) and in noisy operating rooms (10 subjects). For each test an anesthetist first trained the system to recognize his or her voice by reading aloud a list of common anesthetic terms. To determine recognition accuracy, the percentage of words recognized correctly by the computer, each subject repeated the vocabulary words ten times. Although accuracy was similar during the three tests, it was slightly higher with the laboratory test (mean percent of words recognized correctly, 96.5%; range of accuracy for individual anesthetists, 91.6 to 98.8%) than with the prototype test (95.9%; range, 89.1 to 99.6%). Accuracy was lowest with the operating room test (95.3%; range, 87.8 to 98.4%). Twenty-four words caused particular difficulty during the laboratory test and were eliminated from the vocabulary of the subsequent operating room test. Omitting these 24 words from the laboratory vocabulary list allowed a more nearly direct comparison with the results from the operating room list; recognition accuracy improved in the former to 97.5% (range, 92.1 to 98.9%). Two anesthetists--one each from the laboratory and operating room tests--performed poorly, and eliminating their scores changed the respective overall scores to 98.2% (range, 96.7 to 98.9%) and 96.5% (range, 94.3 to 98.4%). Thus, the corrected difference between the laboratory accuracy and the operating room accuracy was 1.7%.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1988

The analytic and functional accuracy of a video densitometry system.

Applications using radiotracers and quantitative film autoradiography are increasing dramatically in the neurosciences. Microcomputer-based image analyzing systems with video input have been developed to provide rapid quantification of autoradiographic images on relatively inexpensive systems. However, there has been some question as to whether such systems can reliably produce high levels of densitometric accuracy, especially when compared to mechanical scanners which are standard in research requiring extreme fidelity of measurement. We report methods and results from tests done to determine the analytical and functional accuracy of the Drexel Unix-based Microcomputer image Analysis System (DUMAS), which is a video densitometric system designed to provide quantitative data from autoradiograms. Analytical accuracy was determined by measuring photometric uniformity, the optical density transfer function, temporal stability, geometric uniformity, and flare. In addition, data are provided on the resolution of the system at several magnifications. Functional accuracy, the accuracy of the estimates of mean isotope concentrations in diverse neural structures, was determined by comparing the results obtained on the DUMAS system with the results from analyzing the same [14C]2-deoxyglucose images with two different Optronics P1000 systems. Our results show that, provided care is taken in the choice of a camera and a light source, the analytic accuracy of videodensitometry is high. Its functional accuracy is also high in that measurements of radioisotope concentrations in diverse neural structures made on the DUMAS system agree closely with the measurements from a properly adjusted Optronics P1000 system. The rapidity and economy of videodensitometry is not, therefore, obtained at the sacrifice of densitometric accuracy. Given adequately tested hardware and provided that suitable checks on instrument calibration and adjustment are made, the errors in autoradiographic quantification due to the image analyzing system itself are minor in comparison to other sources of error, including, as we show, variations in the user's delineation of the boundaries of neural structures.

Autoradiography↗
PubMed1990

The effect of baseline electrocardiographic abnormalities on the diagnostic accuracy of exercise-induced ST segment changes.

Although exercise-induced ST segment depression is thought to be unreliable marker of myocardial ischemia in the presence of resting electrocardiographic changes, this conclusion is based on limited and disparate data from studies often lacking acceptable measures of ischemia. To determine the diagnostic accuracy of the ST segment response in a blinded prospective protocol, we compared ST deviation to thallium201 SPECT scintigraphy in 95 patients during exercise. Diagnostic accuracy was poor in the 95 patients with resting abnormalities: left bundle branch block (LBBB) = 70%, complete right bundle branch block (cRBBB) = 75%, incomplete right bundle branch block (incRBBB) = 79%, intraventricular conduction delay (IVCD) = 44%, left ventricular hypertrophy (LVH) = 59%, digitalis = 53%, compared with a diagnostic accuracy of 90% in 29 patients without resting changes. There were 20 false negative and 17 false positive ST segment responses. The extent and direction of resting ST deviation varied substantially and had no influence on diagnostic accuracy. The extent of change in ST deviation with exercise required for a positive response did not alter diagnostic accuracy: -1.0 mm = 61%, -1.5 mm = 63%, and -2.0 = 61%. While the location of regional ischemia did not influence the accuracy of ST segment analysis, a QRS duration less than 120 msec did improve diagnostic accuracy. Our data confirm that ST segment analysis with exercise testing is not reliable in patients with resting electrocardiographic abnormalities and demonstrates that accuracy is not improved by adjusting for either resting or exercise-induced ST segment changes or for location of the ischemic region.

Aged↗
PubMed1989

Decreased flow accuracy from volumetric infusion pumps.

Accurate flow from infusion pumps should be maintained when exposed to a variety of clinical conditions. The intent of this study was to evaluate in vitro flow rate accuracy of three infusion pumps subjected to the influences of variable back-pressure, solution viscosity, and infusion rates. A factorial study design was selected to determine the influence of three flow rates (5, 10, and 20 ml/h), three back-pressures (100, 200, and 300 mm Hg), and two solution viscosities (5%, 25% dextrose in water) on flow rate accuracy from three infusion pumps (Abbott 4P, IVAC 560, and Travenol 6200) using a standard gravimetric technique. Mean +/- SD accuracy values were -9.4 +/- 6.4% (range -29.1 to -0.7), 0.5 +/- 2.2% (range -4.2 to 6.3), and -0.5 +/- 4.7% (range -8.5 to 9.9) of the desired rate for the Abbott, IVAC, and Travenol devices, respectively. Back-pressure was the only factor to influence significantly flow accuracy for the Abbott device (r = .81). All factors significantly influenced accuracy for the Travenol device (r = .55). No factor influenced accuracy for the IVAC infusion pump. Both the IVAC 560 and Travenol 6200 have acceptable flow accuracy values within the range of study factors examined. The Abbott 4P had significant decreases in flow accuracy in response to increasing back-pressure.

Calibration↗