Computer-generated graphics recorded on film extend minicomputer capabilities.
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Action Potentials↗
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Results for “Computer Graphics”
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Computer-assisted resonance assignments.
Investigation of NMR spectra by automatic procedures began only a few years ago. Many projects are still in progress and results have not been published; completed projects, with published results, have not yet found their final form. Other approaches might be incorporated. One example is the simulation of cross-peaks. These calculations explicitly take into account spectral parameters set for data acquisition and processing. They thus allow realistic simulations of expected peak patterns. Comparison of experimentally obtained peaks with a collection of simulated peaks helps characterize the spin system and determine coupling constants, especially in strongly coupled systems. Whereas automatic assignment procedures will require improvement for quite some time, it seems that useful and time-saving software tools complementing pure computer graphics will be available in the very near future.
Algorithms↗
A medical workstation for the evaluation of alternative 3D radiotherapy treatment plans.
A medical workstation for the evaluation of alternative 3D radiotherapy plans is described. Our system can simultaneously apply qualitative as well as quantitative evaluation methods to as many as three 3D dose distributions. The user interface of the workstation has been designed with the demands of radiation oncologists in mind. The handling of the large amounts of 3D data (CT data, up to three 3D dose distributions, volumes of interest) is assisted by computer graphics.
Computer Graphics↗
Computer-generated graphic models of the N2-substituted deoxyguanosine adducts of 2-acetylaminofluorene and benzo[a]pyrene and the O6-substituted deoxyguanosine adduct of 1-naphthylamine in the DNA double helix.
Computer models of three deoxyguanosine-carcinogen adducts in double-helical DNA are presented. The carcinogen moiety is rotated and the best fit within the double helix is evaluated. The 2-acetylaminofluorene (AAF) derivative, 3-(deoxyguanosin-N2-yl)-AAF, is found to be situated within the minor groove, has very little freedom of rotation and causes little helical distortion. The (+)-anti-benzo[a]-pyrene (BP)-diol epoxide-N2 adduct, 10beta-(deoxyguanosin-N2-yl)-7beta, 8alpha,9alpha-trihydroxy-7,8,9,10-tetrahydro-BP, has a similar fit with a greater degree of steric interaction, suggesting that this adduct could cause some local destabilization. The 1-naphthylamine (NA) derivative, N1-(deoxyguanosine-O6-yl)-1-NA, resides within the major groove, does not perturb the helix and has considerable freedom of movement.
1-Naphthylamine↗
The image-combining computer microscope--an interactive instrument for morphometry of the nervous system.
The image-combining computer microscope is a new configuration of light microscope and computer graphics instrumentation which provides remarkable morphometric capabilities over a wide range of applications. The key component is the well known camera lucida, an image-combining device that is used to superimpose the computer graphics image upon the microscope's image of the object under study. Illumination need not be limited to the bright-field variety. The image superposition permits the investigator to study the object and acquire data from it while always looking through the microscope oculars. A computer controlled stepping motor driven stage is integrated with translations of the graphics image to permit image superposition and data acquisition at maximum visual magnification over the full expanse of a 25 X 25 mm tissue section. The investigator controls the system by means of a graphics tablet and a "Menu" area visible to him in the microscope's field of view. Spatial data in all 3 dimensions can be acquired easily since the z-axis is also stepping motor controlled. EM micrograph transparencies can be studied similarly. Stereological applications are possible by superimposing test grids upon the image. The system is self-contained and carries out data analysis programs written in C or Basic. Simplicity of operation has been emphasized throughout.
Animals↗
Computer simulation of the upper extremities.
The development of real-time, interactive, three-dimensional, computer graphic simulation of the musculoskeletal system with emphasis on the upper extremities is described. Developments in image analysis, scientific visualization, and interactive computer methods and the continuous improvement in knowledge of musculoskeletal function have combined to provide an exciting new tool for musculoskeletal research. Interactive simulation also has promising applications in medical education and clinical rehabilitation. Only those developments that fit the specific criteria of realism, real-time response, intuitive interaction, three-dimensional structures, and modeling flexibility are discussed. It is hoped that an improved understanding of this emerging tool and an appreciation for its potential applications will be gained.
Arm↗
Three-dimensional surface descriptions from sensed data.
Computer graphics are being employed in several fields to display images of objects that have never been seen by human eyes. The information collected by CAT scanners, ultrasound sensing systems, and other automatic measuring devices is typically not in a displayable form. This paper surveys several techniques for constructing three-dimensional descriptions of these sensed objects in forms suitable for manipulation by computer graphics display programs.
Computers↗
Interactive computer surface graphic study of the binding of an antibody to the chromatin subunit.
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Binding Sites, Antibody↗
Computer-generated graphic evaluation of nutritional status in critically injured patients.
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Computers↗
Model of a complex between the tetrahemic cytochrome c3 and the ferredoxin I from Desulfovibrio desulfuricans (Norway strain).
A three-dimensional model of an electron-transfer complex between the tetrahemic cytochrome c3 and the ferredoxin I from the sulfate-reducing bacterium Desulfovibrio desulfuricans (Norway strain) has been generated through computer graphics methods. The model is based on the known X-ray structure of the cytochrome and on a model of the ferredoxin that has been derived through computer graphics modeling and energy minimization methods, from the X-ray structure of the homologous ferredoxin from Peptococcus aerogenes. Four possible models of interaction between the two molecules were examined by bringing in close proximity each of the four hemes and the redox center (4Fe-4S) of the ferredoxin and by optimizing the ion pairs interactions. One of these models shows by far the "best" structure in terms of charges, interactions, and complementarity of the topology of the contact surfaces. In this complex, the distance between the iron atoms of the ferredoxin redox center and the hemic iron atom is 11.8 A, which compares well with those found between redox centers in other complexes. The contact surface area between the two molecules is 170 A2.
Amino Acid Sequence↗
Ophthalmic microsurgical robot and associated virtual environment.
An ophthalmic virtual environment has been developed as part of a teleoperated microsurgical robot built to perform surgery on the eye. The virtual environment is unique in that it incorporates a detailed continuum model of the anatomical structures of the eye, its mechanics and optical properties, together with a less detailed geometric-mechanical model of the face. In addition to providing a realistic visual display of the eye being operated on, the virtual environment simulates tissue properties during manipulation and cutting and the forces involved are determined by solving a mechanical finite element model of the tissue. These forces are then fed back to the operator via a force reflecting master and so the surgeon can experience both the visual and mechanical sensations associated with performing surgery. The virtual environment can be used to enhance the images produced by the camera on the microsurgical slave robot during surgery and as a surgical simulator in which it replaces these images with computer graphics generated from the eye model.
Computer Graphics↗
Computerized three-dimensional reconstruction of the crypt system of the palatine tonsil.
The purpose of the present study is to note the three-dimensional structure of the tonsillar crypt using computer graphics methods. The tonsils used herein were human tonsils obtained from the surgical operation, and were cut in serial sections according to ordinary procedures. The crypt contours obtained from the serial sections were used as inputs to the computer (PC-9801 VM) through the image-scanner (PC-IN 502). The three-dimensional structure of the human tonsillar crypt revealed by computer graphics, showed that the crypts had not only branches but also anastomosis, and that they could divide into two types, a simple unbranched crypt and a complicated branched one. Generally, the simple type of crypt was located in the peripheral zone of the tonsils and the complicated type in the central zone. These findings are discussed briefly and with reference to previous reports.
Child↗
Imaging workstations for computer-aided primatology: promises and pitfalls.
In this paper, the application of biomedical imaging workstations to primatology will be explained and evaluated. The technological basis, computer hardware and software aspects, and the various uses of several types of workstations will all be discussed. The types of workstations include: (1) Simple - these display-only workstations, which function as electronic light boxes, have applications as terminals to picture archiving and communication (PAC) systems. (2) Diagnostic reporting - image-processing workstations that include the ability to perform straightforward manipulations of gray scale and raw data values will be considered for operations such as histogram equalization (whether adaptive or global), gradient edge finders, contour generation, and region of interest, as well as other related functions. (3) Manipulation systems - three-dimensional modeling and computer graphics with application to radiation therapy treatment planning, and surgical planning and evaluation will be considered. A technology of prime importance in the function of these workstations lies in communications and networking. The hierarchical organization of an electronic computer network and workstation environment with the interrelationship of simple, diagnostic reporting, and manipulation workstations to a coaxial or fiber optic network will be analyzed.
Animals↗
Modification of paradoxical sleep following transections of the reticular formation at the pontomedullary junction.
A retractable wire knife was employed to transect the reticular formation at the pontomedullary junction in order to assess the respective importance of pontine and medullary reticular neurons and their pathways in paradoxical sleep. Thirteen cats were implanted with a standard array of electrodes for polygraphic recording of sleep-wakefulness states during 3 days in baseline condition and during 21 days after transections. Average electroencephalographic (EEG) amplitude, average electromyographic (EMG) amplitude, and ponto-geniculo-occipital (PGO) spike rate were measured per 1-min epoch for each day. A trivariate computer graphics display of 1 day's data revealed three major clusters of points that corresponded to wakefulness, slow wave sleep, and paradoxical sleep in baseline. (a) After transections through the entire reticular formation at the pontomedullary junction, paradoxical sleep was no longer evident in the trivariate computer graphics or polygraphic record, either by the presence of a high PGO spike rate or by that of muscle atonia in association with a low-amplitude EEG. These results indicated that the reticular fibers that pass through the pontomedullary junction and interconnect the pontine tegmentum and the medullary reticular formation are necessary for generating the cluster of electrographic variables that normally characterizes paradoxical sleep. (b) After transections through the dorsal half of the reticular formation, paradoxical sleep was still evident, though with a reduced PGO spike rate, and muscle atonia was normal. These results indicated that the descending noradrenaline locus coeruleus fibers and the "longitudinal catecholamine bundle," which course through the dorsal tegmentum, are not necessary for the generation of muscle atonia or the state of paradoxical sleep. (c) After transections through the ventral half of the reticular formation, paradoxical sleep was still apparent by the association of a moderate, though reduced, rate of PGO spiking in association with low-amplitude EEG activity and a high-amplitude EMG, indicating a loss of muscle atonia. The duration of the PS episodes, however, was greatly reduced. These results indicated that the descending "tegmentoreticular" and ascending reticulotegmental pathways, which course ventrally through the pontomedullary junction and interconnect the dorsolateral pontine tegmentum and the ventromedial medullary reticular formation, are essential for the muscle atonia of paradoxical sleep and important for the normal cyclic generation and maintenance of the state of paradoxical sleep.
Animals↗
HAMOG: molecular graphics program for chemistry, biochemistry, molecular biology and enzyme research.
HAMOG is a computer graphics program written in C for personal computers. Clear menus and a context-sensitive help option make the program easy to operate for occasional users. HAMOG provides a flexible environment for displaying and manipulating molecules and molecular systems. Special functions allow the investigation of structure-activity relationships of biologically active molecules. These include the calculation of molecular electrostatic potentials and fields, the superposition of molecules and the calculation of steric accessibilities. The visualization and manipulation of protein structures immediately readable from the Brookhaven Protein Data Bank files are also possible using HAMOG. The construction of any peptide or protein structure is very simple.
Chemical Phenomena↗
Computer- and robot-assisted resection of thalamic astrocytomas in children.
Six children ranging in age from 2 to 10 years who harbored deep benign astrocytomas were operated upon using a computer- and robot-assisted system. A radical excision was achieved in all cases with no significant morbidity nor any mortality. The system consists of an interactive, three-dimensional display of computed tomographic image contours and digitized cerebral angiograms taken using the Brown-Roberts-Wells stereotactic frame. The surgical retractor is held and manipulated using a PUMA 200 robot. The position and orientation of the surgical retractor is displayed on the three-dimensional display. Preoperative planning and simulation are important features of this system. Movement of the brain after removal of the tumor and cerebrospinal fluid is substantial, so the tumor removal is based on visually defined margins. Enhanced computer graphics and robotic devices are important adjuncts to neurosurgical procedures and will find increasing use in the future.
Astrocytoma↗
Motor end-plate distribution in the human interarytenoid muscle.
Histochemical and computer graphic techniques were used to determine the distribution of neuromuscular junctions in the human interarytenoid (IA) muscle. The motor end-plates of four IA specimens obtained from normal postmortem larynges were visualized using an acetylcholinesterase stain. The three-dimensional distribution of motor end-plates was later reconstructed using computer graphics. The motor end-plates in the IA were found to be distributed in an inverted "Y" configuration. A broad band of end-plates was found at the midpoint of the muscle fibers in the superior and middle aspect of the muscle. This band divided obliquely in a lateral direction toward the inferior border of the muscle. This pattern of motor end-plate distribution is possibly consistent with the bilateral innervation of the IA by the recurrent laryngeal nerves.
Adult↗
On the development of an integrated computer system for cephalometric analyses.
This paper describes a microcomputer based system that integrates image processing and computer graphics techniques to automate the data extraction and storage process in cephalometric analyses. The system increases the consistency of measurements and improves the productivity of surgical and dental staff.
Cephalometry↗