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At least 667 records · Page 37Linked to original sources
PubMed2003

[Cephalometric study of Holdaway analytical method by computer on 58 adults with normal occlusion in Chongqing].

OBJECTIVE: In order to establish the normal value of Holdaway analytical method of Chongqing and to reveal the regular patterns and characteristics concerning the craniofacial morphology. METHODS: 58 students, with permanent dentition were selected as the samples. The cephalometric images were scanned into a computer and the images were imported into the program. The cephalometric analysis were automated by the computer. The cephalometric analytical method of Holdaway was used in this study. Correlational analysis were calculated. RESULTS: The normal values of Holdaway analytical method for permanent denition on normal occlusal adults of Chongqing were established and compared with that of Pekingman, Japanese and White man. CONCLUSIONS: We found that soft cephalometric measurement values are various in sex and races and regional population. There were correlations between hard and soft tissues.

Adolescent↗
PubMed1986

Cross-correlation analysis of intracellularly recorded synaptic activities: an evaluation of the method through computer simulation.

Cross-correlation of 'spontaneous' synaptic activities intracellularly recorded from pairs of neurons may be used to detect shared synaptic input, which could remain hidden in the raw data by the non-synchronized postsynaptic potentials (PSPs); besides, if a normalized cross-correlation function is adopted, the fraction of synchronized activity may be quantitatively estimated. To evaluate power and limits of this method, computer-simulated synaptic activities of pairs of neurons, in which a given percentage of PSPs were simultaneous, were subjected to this type of analysis. It was shown that percentages of shared activities as low as 4% and in some cases 2% could be revealed, with a conspicuity which was influenced by the types of associated PSPs.

Action Potentials↗
PubMed1985

Fast method for computing the Fourier integral transform via Simpson's numerical integration.

A new algorithm for computing the Fourier transform is described. The method is based on the calculation of the Fourier integral transform (FIT) with the aid of the numerical Simpson's integration technique. Compared to the conventional fast Fourier transform (FFT), the new SFIT algorithm, gives results which are much closer to the analytic Fourier transform for discrete signals. Especially in the calculation of the phase spectra considerable improvement is obtained. The N-point SFIT can effectively be computed by using two N/2-point FFTs.

Biomedical Engineering↗
PubMed2002

A personal-computer-based method to obtain "star-shots" of mechanical and optical isocenters for gantry rotation of linear accelerators.

This work describes a method to obtain "star-shots" of the mechanical and optical isocenters of linear accelerators, similar to the star-shots of radiation isocenters normally obtained using films. In this method a digital camera is connected to a personal computer so that multiply exposed images can be taken at a fixed camera position. A mechanical pointer or a wire aligned along the optical axis can then be imaged by the camera. Multiple exposures at varying gantry angles are then superimposed on a digital image which can be analyzed by the computer to give a high-resolution star-shot. The method provides a convenient way for a linear accelerator quality assurance procedure.

Computer Simulation↗
PubMed2004

Analysis of the mechanism of retention on graphitic carbon by a computational chemical method.

Retention mechanism on a graphitic carbon was analyzed by computational chemical calculation. The model graphitic carbon phase was a large polycyclic aromatic hydrocarbon (PAH) and analytes were carbohydrates and hydrocarbons separated by liquid and gas chromatography. Molecular mechanics calculation was fast and suggested their retention order and main retention force. Molecular orbital package calculation (MOPAC) demonstrated their complex form.

Graphite↗
PubMed1990

Computer-assisted methods for assessing strain relatedness in Candida albicans by fingerprinting with the moderately repetitive sequence Ca3.

When used to probe EcoRI-digested Candida albicans DNA, the moderately repetitive sequence Ca3 generated a Southern blot hybridization pattern which included 15 to 25 bands, depending upon the strain. The pattern was stable through 400 generations in each of three independent strains but variable between most of 46 unrelated tester strains, making it a very effective probe for discrimination between strains. Computer-assisted methods (Dendron) were developed for storage of Ca3 patterns in data files, calculation of similarity (SAB) values between strains based upon band positions and intensities, and generation of histograms and dendrograms based on SAB values for all strains or any subset of strains in large epidemiological studies. In testing the effectiveness of the system, it was found that (i) multiple isolates from different body locations of the same healthy individual could represent either the same strain or different strains, (ii) isolates from oral lesions of a husband and wife represented the same strain, (iii) strains isolated from the mouths of 10 healthy individuals on the same day and in the same geographical location were as dissimilar on average as the 46 unrelated tester strains, and (iv) strains isolated from seven immunocompromised patients hospitalized over a 2.5-month period in the same hospital were highly similar, indicating nosocomial origin. The apparent effectiveness of these fingerprinting methods and the Dendron program suggests that interlaboratory procedures for fingerprinting should be standardized and all patterns should be analyzed and stored in a common and accessible data base for broad epidemiological analysis.

Blotting, Southern↗
PubMed1977

Lifetime covered earnings and quarters of coverage of retired and disabled workers, 1972.

This article presents information on the lifetime covered earnings of retired-worker and disabled worker beneficiaries under OASDHI, the year of their first earnings credits, their quarters of coverage, and the relationship of these factors to 1972 benefit levels. Among both groups, relatively more women began earning credits after 1940; they also worked fewer years in covered employment and had lower lifetime earnings overall. Their benefits were thus smaller than those of men. White men tended to have higher lifetime covered earnings than did black and other men, but the latter sometimes had lifetime earnings that exceeded those of white women with equal quarters of coverage. Black women and those of other minority races tended to have the lowest lifetime covered earnings. Both retired and disabled workers whose covered employment began after 1950 were likely to have benefits as high or higher than the benefits of those with earlier credits--a reflection of rising wage levels and higher taxable maximums, as well as the "new start" computation method. as well as the "new start" computation method.

Adult↗
PubMed1983

A computer-compatible method for observing falling asleep behavior of hospitalized children.

A family-organizational linkage framework was used to conceptualize the nighttime separation behaviors of 18 hospitalized children, ages 3 to 8, whose parents did not room-in. All children were observed for three consecutive nights during the falling asleep period. A bedtime story, tape recorded by the parent, was played on the second and third nights for one group. Frequency and duration of falling asleep behaviors were recorded and analyzed with the Senders Signals and Receivers System, a computer-compatible method of recording behavioral data. Eight conceptual behavioral categories emerged from the data: sleepy, contact, active, inactive, neutral, communication, distress, and pleasure. The story-children fell asleep sooner (23 minutes vs. 28 minutes), exhibited more sleepy behaviors, and displayed fewer active behaviors. Duration of contact behaviors also was greater in this group (22 minutes vs. 14 minutes). Hospitalized children who hear a bedtime story recorded by a parent appear to use self-soothing behaviors to cope with the separation experience.

Child↗
PubMed1985

A computer-assisted method for averaging movement-related cortical potentials with respect to EMG onset.

The recording of movement-related cortical potentials (MRCP) relies on the use of EMG activity or some other index of movement as a trigger for averaging. EMG activity can vary considerably from one movement to the next, particularly in patients with movement disorders. This results in an MRCP formed from individual sweeps which are averaged with respect to differing periods during the EMG activity. We describe a computer-assisted method for identifying EMG onset associated with each movement made by the subject. The method allows the experimenter to reject trials associated with artefacts or with spurious trigger pulses produced by resting EMG activity. It is also possible to average the MRCP into categories associated with differing EMG characteristics such as EMG duration, peak EMG amplitude and the duration from EMG onset to peak. Using this method we have been able to record reliable MRCP from patients with movement disorders in whom this would otherwise have been technically impossible.

Cerebral Cortex↗
PubMed1997

Chemotaxis of Amoeba proteus in the developing pH gradient within a pocket-like chamber studied with the computer assisted method.

A new "U" shaped, pocket-like chamber was used to observe the chemotactic responses of individual cells. This method permits monitoring of both the development of the concentration gradient of a tested substance and cell locomotion. We investigated the chemotactic responses of Amoeba proteus and observed that the amoebae moved in positively and negatively developing [H+] gradients towards the solution of lower pH in a pH range 5.75-7.75. The chemotactic response of amoebae to [H+] gradients required the presence of extracellular calcium ions. It was blocked and random locomotion was restored by the replacement of calcium with magnesium in the cell medium. Time-lapse video recording and data processing were accomplished with computer-assisted methods. This made it possible to compare selected methods of data presentation and analysis for cells locomoting in isotropic and anisotropic conditions. The cell trajectories were determined and displayed in circular diagrams, lengths of cell tracks and final cell displacements were estimated and a few parameters characterizing cell locomotion were computed.

Amoeba↗
PubMed1993

Muscle damage progression in Duchenne muscular dystrophy evaluated by a new quantitative computed tomography method.

The progression of muscle damage was studied in the lower extremity and trunk muscles of patients with Duchenne muscular dystrophy (DMD) with a new quantitative computed tomography (CT) method. The degree of muscle fiber loss and fat tissue replacement was quantified using the indices of percent cross-sectional area (%CSA) of muscle and fat, or the percentages of the area having the CT numbers of normal muscle and fat. A cross-sectional study in 71 patients showed that as the disability stage progressed, both CT number and %CSA of muscle decreased while %CSA of fat increased. The rate of progression was different for each muscle, and the order of involvement was clarified. The CT findings were also significantly correlated with muscle strength, indicating validity of our method. Our findings of the natural course of muscle involvement would be useful in providing appropriate rehabilitative care as well as assessing the efficacy of therapeutic interventions.

Adolescent↗
PubMed1982

Fluid dynamics of the mitral valve: physiological aspects of a mathematical model.

This paper presents a computational method that can be used to study the fluid computational method that can be used to study the fluid dynamics of the natural or prosthetic mitral valve in a computer test chamber with contractile muscular walls that model the left side of the heart. Having solved the equations of motion and predicted the performance of the valve, the computer presents the results in terms of flow patterns (streamlines), pressure-contour plots, and graphs of velocity, pressure, flow, tension, and distance as functions of time. Predicted echocardiograms and phonocardiograms are also generated by the computer. These predictions are compared with the results of animal experiments, and the method is used to study the diastolic role of the chordae tendineae, the pathophysiology of mitral valve prolapse syndrome, and the fluid dynamics of pivoting disc valves. Our results support the hypothesis that the chordae have a functional role during diastole. The results also establish a computer model of mitral prolapse, which should be useful in functional studies of that condition, and show that the position of the pivot point and the curvature of the occluder can have a profound effect on the angle of opening of pivoting disc valves. These studies illustrate the applications of the method in physiology, pathophysiology, and prosthetic valve design.

Animals↗
PubMed1999

[The results and outlook for the use of mathematical methods and computer technology in dentistry].

Development and introduction into wide practice of various mathematical methods (systemic, regression, and factor analyses, etc.) and modern computation devices (personal computers, local computer network, etc.) is shown. These devices extended the potentialities of differential diagnosis and pathogenetic (including laser) therapy of the major oral diseases (dental carries, pulpitis, periodontitis, periodontal diseases and buccal mucosa, odontogenic inflammations, tumors, etc.).

Computing Methodologies↗
PubMed1976

Computer simulation of movement-generating cross-bridges.

A stochastic computational method was developed to study properties of cross-bridge models for muscle contraction, by following the time history of individual cross-bridge model of Andrew Huxley (1957) and a modified two-state model with more realistic behavior during steady stretching are used as examples. The method can readily compute steady-state force during shortening and stretching and force-transients following rapid changes in length. Computations of velocity with a steady load and of velocity transients are more sensitive to the randomness inherent in the stochastic method.

Computers↗
PubMed1996

Development of an interactive computer-guided method for radiofrequency catheter ablation of ventricular tachycardia.

The purpose of this study was to develop a simple computer-guided approach to localizing ventricular tachycardias during ventricular mapping. Six patients with sustained monomorphic ventricular tachycardia were connected to a 32-lead computer body surface mapping system. Isoarea maps of induced ventricular tachycardia were recorded. Then a pacing probe was placed in either the right or left ventricle, and maps were generated from a variety of sites. Differences between ventricular tachycardia and pace map maxima X, Y coordinates were utilized to guide catheter manipulation and localization. In 6 of 6 patients (100%) this method appeared to provide a systematic approach to ventricular tachycardia localization. Computer-generated correlations as well as the X, Y coordinates of the QRS isoarea maxima were used to determine proximity to the ventricular tachycardia foci and direct catheter manipulation. In the next three patients this method was applied prospectively to help guide catheter manipulation during ventricular tachycardia (two right ventricular outflow tract tachycardias, and one left ventricular tachycardia). After a mean of 4.0 +/- 1.7 radiofrequency applications, ventricular tachycardia was no longer inducible, and at 7 +/- 0 months follow-up there have been no arrhythmia recurrences. We conclude that online computerized body surface mapping can assist in localizing ventricular tachycardia. Differences in maxima during pace maps and in-situ ventricular tachycardias can help with catheter manipulation as well as with more precise identification of focal tachycardias. This technique appears to hold the promise of a simple computer-guided method that may facilitate radiofrequency catheter ablation.

Adult↗
PubMed2001

Validating a double-press method for computer administration of personality inventory items.

This study describes a double-press method for experimentally controlling item length and reading speed when measuring response latency to computer-administered personality items. Previous research has required several statistical transformations to control for item length and reading speed. Five approaches validated the new, double-press method. First, valid profiles showing reasonable read time and psychological response time resulted in few outliers. Second, read and psychological response times were internally consistent. Third, valid separation of read time from total response time was demonstrated by a positive relationship between read time and item length. Fourth, negatively stated items took longer to understand than positively stated items. Fifth, in accordance with schema research, items that were highly similar or dissimilar to the self-schema were answered more quickly than other items, resulting in an inverted-U effect.

Adolescent↗