Digital Planimeter Research Articles

Analysis of the point-counting and planimetric methods in the quantification of denture biofilm--a methodological validation study

Two methods of quantification of the biofilm (point-counting and planimetric) were tested and compared with the paper-weighing method and with the Prosthesis Hygiene Index. The internal surfaces of 62 complete dentures were stained and photographed. The slides were projected on a paper sheet. The total area and the area covered with biofilm were contoured using a black pencil. The point-counting method (experimental 1) was carried out on a mesh of equidistant points. For the planimetric method (experimental 2), the areas of interest were measured by means of a digital planimeter. In the paper-weighing method (control 1) the areas of interest were cut and weighted on a precision scale. In the determination of the Prosthesis Hygiene Index (control 2), the accumulation of biofilm was estimated by means of a scoring method. The results revealed an agreement rate of 82% between the paper-weighing method and the point-counting method, and an agreement rate of 95% between the former and the planimetric method, which was confirmed by high coefficients of correlation (0.98 and 0.99, respectively). The comparison with the Prosthesis Hygiene Index resulted in 55% of agreement with the point-counting method and in 37% of agreement with the planimetric method. The experimental methods can be useful in clinical studies involving the evaluation of the performance of denture cleansers.

The structure of bovine periodontal ligament with special reference to the epithelial cell rests.

The aim of this study was to determine the structure of the bovine periodontal ligament, with special reference to epithelial cell rests (ECR) and their cytokeratin content. Periodontal ligament was obtained from bovine molar teeth and studied at both the light microscopic and electron microscopic levels. Cytokeratin content was determined using immunohistochemistry against a number of cytokeratin antibodies and specificity tested against bovine and human oral mucosa. Collagen fibril diameters and the area of a fiber bundle occupied by collagen were determined using a digital planimeter with a digitizing tablet. The majority of periodontal fibroblasts possessed considerable quantities of roughened endoplasmic reticulum, indicating rapid synthesis and secretion of collagen, but no intracellular collagen profiles were present. Endothelial cells showed Weibel-Palade bodies. Collagen fibril diameters showed a unimodal distribution with a mean collagen fibril diameter of 55.3 nm. The mean percentage area of the extracellular matrix occupied by collagen was 42%. Structurally, ECR were unusual in exhibiting large numbers of microvilli and conspicuous amounts of cytokeratin filaments. Bovine ECR showed a positive reaction to the pancytokeratin MNF116 (which reacts with the cytokeratins 5, 6, 8, 17, and probably 19), to PCK-26 (which reacts with the type II cytokeratins 1, 5, 6, and 8) and to cytokeratin 13. There was no reaction for cytokeratins 1, 4, 10, 11 and 18. Structurally, bovine periodontal ligament showed features common to other species. However, ECR in terms of both structure and cytokeratin content showed features indicative of important species differences which may have relevance when considering the etiology of radicular cysts.

Failure of ceramic/fibre-reinforced plastic composites under hypervelocity impact loading

The hypervelocity impact limit, V50, of alumina/fibre-reinforced plastic (FRP) target materials was studied with different adhesive layer thicknesses and two kinds of FRP. A high-speed camera was used to analyse the perforation phenomena of target materials. In addition, the dishing and bulging extent of FRP as a rear material were investigated using a digital planimeter from a series of high-speed photographs during the perforation of a projectile. In the case of the same adhesive layer thickness, the target material with more ductile FRP (A type) absorbed more impact energy than that with less ductile FRP (B type). In both target materials, the highest V50 was obtained at an adhesive layer thickness of 1.3 mm.

Side-to-side earlobe variations with respect to surface area and shape: a quantitative study.

Side-to-side earlobe variations, based on the size of the earlobe surface area and a classification into earlobe types, were quantitatively analyzed in 58 female students, ranging from 20 to 22 years old. Using a new earlobe measurement technique, a closed-circuit outline of each ear was directly traced onto a clear polyethylene sheet, after which the surface area of the earlobe portion of each ear was identified, measured by a digital planimeter, and analyzed. Results revealed that side-to-side differences in the size of the earlobe surface area existed in all subjects. In contrast, based on classifying the earlobe shape into three types (i.e., tapering, square, or pendulous), differences in the mean earlobe surface area value among the three types were not significant. However, when the classification of the earlobe shape was reduced to only two types (pendulous or nonpendulous), the mean earlobe surface area value between the two types was highly significant. These results thus suggest that for a quantitative analysis of earlobe variations, classification of the earlobe shape into two types rather than into three types is the better method. This method makes it easy to distinguish earlobe differences. Further, if the earlobe differences are noted before ear piercing, a balanced ear piercing effect can be achieved.

Comparison of manual and morphometric analysis techniques for rat hepatocyte peroxisomes

It has been well documented that ethanol is toxic to hepatocytes and that peroxisomes are key organelles in the metabolism of ethanol. Lieber (1985) has confirmed that when rats are fed a 30% ethanol-derived calories diet for three weeks there are noticeable ultrastructural changes such as the accumulation of lipid (steatosis) and the hypertrophy of the smooth endoplasmic reticulum. We sought an efficient costeffective technique for obtaining reliable quantitative documentation of subtle changes within organelles of hepatocytes after rats were fed a 30% ethanol-derived calories diet for two weeks. One hundred micrographs of match paired ethanol-fed rats (n = 5) were compared with 100 micrographs of controls (n = 5) and analyzed by the point counting method; with a digital planimeter using SigmaScan/Image software (Jandel Inc.) and calculations were made using Excel v. 4.0 (Microsoft Corp.); as well as with Optimas image analysis software (Bioscan). Micrographs were taken with a Zeiss EM 10 transmission electron microscope.

Changes in the Cervical Foraminal Area after Anterior Discectomy with and without a Graft

A controversial point in the management of patients undergoing anterior cervical discectomy is whether an interbody bone graft should be used. Proponents of interbody grafting claim that without a graft, the disc height and the area of the foramina at that level will decrease postoperatively with the potential for persistent symptoms and/or the development of a radiculopathy. Using a two-dimensional digital planimeter, we measured the cross-sectional area (cm2) of cervical foramina on preoperative and postoperative oblique films in patients undergoing anterior cervical discectomy. Group A patients underwent the insertion of an interbody graft after the discectomy; Group B patients did not. Our results indicate that in all the patients in Group A, there was a statistically significant increase in the area of the foramina (P < 0.001) and in Group B, a statistically significant decrease (P = 0.0005). However, when the absolute change in magnitude of the foramina was measured, without respect to an increase or decrease, there was no statistically significant difference (P > 0.8). There was no statistically significant difference (P = 1.000) in the outcome between the two groups. From an anatomical standpoint, our data support the insertion of an interbody graft if the surgeon wishes to increase the area of the foramen. However, the overall magnitude of change is not significant, which may be a factor in why the clinical outcome is similar in both groups.

Circulating beta-atrial natriuretic factor in congestive heart failure in humans.

beta-Atrial natriuretic factor (beta-ANF) is an antiparallel dimer of alpha-ANF (alpha-ANF) with diminished cyclic GMP generation in vitro. To date, the presence of beta-ANF in the circulation of humans with severe congestive heart failure (CHF) remains controversial. The current study was designed to determine the presence and magnitude of circulating beta-ANF in severe CHF, to correlate plasma beta-ANF with the degree of ventricular dysfunction, and to investigate the role of human plasma and atrial tissue in the degradation of beta-ANF. Venous plasma samples were obtained from patients (n = 12) with severe CHF and normal volunteers (n = 8). Total plasma ANF was measured by radioimmunoassay. alpha-ANF and beta-ANF in nonextracted plasma were separated by gel filtration chromatography using a P-6 column. Right atrial tissue samples (n = 5) were collected from a different group of patients at the time of open-heart surgery. 125I beta-ANF and I125 ANF were incubated with atrial tissue or plasma. The corresponding peak areas of beta-ANF were determined by Tamaya Digital Planimeter. beta-ANF represented 61% of total plasma ANF in CHF patients and was not detected in normal human plasma. The elevation of beta-ANF correlated with the severity of ventricular dysfunction. Thirty percent of beta-ANF and 100% alpha-ANF were converted to smaller peptide fragments in atrial tissue no conversion in plasma. beta-ANF is the principal form of circulating ANF in patients with severe CHF and correlates with the degree of left ventricular dysfunction. beta-ANF is not generated from alpha-ANF and may be degraded rapidly in atrial tissue to smaller peptide fragments that do not occur in plasma. As beta-ANF is reported to have reduced biological action, the current studies may support the conclusion that the ANF system in CHF has reduced functional activity despite increases in circulation concentrations.

Effect of fin length on solidification rate in a latent heat energy storage system

ABSTRACT The main problem encountered in Latent Heat Energy Storage (LHES) Systems is to find and apply the methods increasing phase change rate. The use of finned heat exchange surfaces seems to be an attractive way among several methods handling that problem. The aim of this work is to ascertain the usefulness of finned surfaces in a LHES unit including a definite amount of Phase Change Material (PCM) and to determine the effect of fin length on phase change rate. For that purpose, solidification of liquid water whose initial temperature was at the fusion value was analysed for three different types of heat exchange surfaces; namely without fin, with a short fin and with a long fin. Experiments were carried out for three different average base temperatures of the finned surface. During the experiments slides were taken from the frontal face of the solidification unit at predetermined time intervals. The images were projected on a flat surface in full scale and the areas defined by solidification contours were evaluated with a digital planimeter. Solidification quantity vs. time curves obtained for three different types of heat exchange surfaces are compared. It is concluded that long fins are more effective in enhancing solidification rate.

Morphometric analysis of peroxisomes in hepatocytes of alcohol-fed rats

Peroxisomes which participate in 1ipid metabolism have been shown to be altered in several metabolic disorders and toxic conditions. In alcoholic liver disease, the single lesion most frequently found is lipid accumu1ation in hepatocytes. However, the mechanisms for this 1ipid accumu1ation are not clear. The occurrence of modifications of liver peroxisomes due to excess alcohol consumption has not been subjected to a controlled study. We utilized a combination of cytochemica1 and morphometrictechniques to study the size and number of liver peroxisomes in rats fed an alcohol-supplemented diet compared to those of matched-paired control animals.Male Sprague-Daw1ey rats (400-500 g) received a liquid diet. The experimental group (N = 5/group) was fed a diet containing 30% ethanol-derived calories (EDC) and the control group was fed an isocaloric diet to 30% EDC. A pair feeding procedure was employed to control for caloric intake. Small pieces of liver randomly selected, were fixed in 2.3% -glutaraldehyde in 0.1 M sodium cacodylate buffer, pH 7.2, incubated in a DAB medium and postfixed with. 2% aqueous osmium tetroxide. EM photographs were taken from sections of 3 tissue blocks from each sample (7,200X) with a Zeiss EM10-A (60 kV). With the use of a point counting method and a digital planimeter the volume density (Vv) and numerical density (Nv) were determined.

Movements and Activity Patterns of the Light-Footed Clapper Rail

We monitored 54 individually color-banded light-footed clapper rails (Rallus longirostris levipes) (9 were harnessed for radio telemetry) to determine movements, home range, and activity patterns. Resightings over 3 years indicated a strong site tenacity. Maximum distances between locations for a given rail were generally 95%) was done during daylight hours. To check for nighttime activity, fixes were taken on 4 rails every 2-3 hours through 1 night each. Of our total tracking effort, 37% of locations were obtained in the first 4 hours of daylight, followed by 19, 26.9, and 16.5%, respectively, in consecutive 4-hour time blocks. Position fixes were taken every 15-30 minutes. Rails under visual observation yielded more fixes/unit of time, whereas rails roosting through high tides did not change position and, therefore, were not checked as often. Tracking stations were situated along the edge of the marsh, 15-50 m apart. The telemetered rails were within 50 m of the observer. The presence of an observer did not appear to affect a rail's behavior because rails were habituated to human activity (e.g., biking, jogging, class tours, boating, driving, and picnicing). Two or more readings were taken within 515 minutes, to determine a single location for a telemetered rail by triangulation. The data were entered into a computer that converted our compass readings to Cartesian coordinates. The program discarded fixes with >3 readings that crossed >5 m apart. A graphics plotter displayed the spread of fixes for a rail on maps of approximately 1:1,719-1:4,132 scale. Movements and range were measured on these maps with a digital planimeter and calipers. Home ranges were calculated using minimum convex polygons. We assessed activity patterns based on visual observations of the 4 most frequently observed telemetered rails and the mate of 1 of them. We quantified vocalizations by counting each bout of calling by each rail as 1 vocalization. We sexed rails by observing the behavior of m ted pairs. Also, the females of mated pairs were always smaller than the males. This size difference was corroborated by the measurement of 100 museum skins, measurements of 12 rails subsequently observed mating, and measurements of 5 birds later found dead and examined by laparotomy. Birds referred to by sex, herein, are only those observed mating or later dissected.

An inexpensive and interactive microcomputer system for codifying golgi-impregnated neuronal morphology

An interactive microcomputer system has been developed for the quantitative analysis of Golgi-impregnated neuronal morphology (GINM). The system uses commercially available hardware: a 48K RAM microcomputer (Apple II), a TV monitor (NEC), an optical microscope (Reichert Biovar) with a camera lucida and a specially developed wheel attached to the focus adjustment knob and to a digital planimeter (Tamaya), allowing one to obtain the value of the z-coordinate. The x- and y-coordinates are obtained using the movement of a point plotted by the computer on the TV monitor. This point is superimposed upon the GINM point to be codified employing the camera lucida. The x- and y-coordinates are acquired automatically while the variations of the z-coordinate are introduced by the computer keyboard. The three-dimensional coordinates of the selected GINM points and different codes are stored by the computer in a six-dimensional array. The software is written in BASIC. The results demonstrate that the digitization and quantitative analysis of GINM can be achieved with reasonably inexpensive equipment.

Planimetric determination of lung volume and its significance in the radiological diagnosis of pulmonary emphysema

The volume of the lungs of 102 patients with emphysema and of 33 normal individuals, aged between 30 and 79 years, was determined with the use of a digital planimeter from routine chest x-rays in two planes. Contrary to the values obtained by a helium dilution method, the volumes, as determined by planimetry, did not show a linear relationship with age, but showed an increase after the age of 60. This agrees with the results of total body plethysmography, carried out by Amrein et al. The planimetric method of Harris, Pratt and Kilburn is a simple and rapid method for demonstrating, even in the presence of regional ventilatory abnormalities, total volume with sufficient accuracy, which complements and quantifies the radiological diagnosis of emphysema.

Computer controlled digital planimeter

An automatic digital planimeter is described. The system consists of a desktop computer, digital plotter, and high-resolution reflectance sensor. It operates on simply connected curves by first scanning and digitizing the figure, and then carrying out a numerical integration on the stored data. A test case confirms that the area evaluations are quite accurate.

A simple digital morphometry system for electron microscopy

Three-dimensional structural parameters can be obtained quantitatively from two-dimensional images using the methods of stereology and morphometry. One method of obtaining data for a morphometric analysis is digital planimetry. An easily constructed and inexpensive digital planimeter for morphometry is described. The programs written specifically for this system generate lengths and areas as the operator traces along lines and profiles in a micrograph placed on a digitizing tablet. A number of operational options can be selected by the operator, including measurement of open or closed lines, summation of a series of profiles, automatic closure, etc. The spatial accuracy and speed of the system assures that accuracy is not limited by the device itself but only by the operator's ability precisely to follow contours in the micrograph.

A Relatively Inexpensive Microprocessor-Linked Digital Plamimeter for Electron Microscopic Morphometry

Stereology provides a theoretical basis for powerful morphometric methods for the estimation of three-dimensional structural parameters from two-dimensional electron micrographs of cells and tissues. These methods assume at the start that one has a sufficiently large set of micrographs containing valid structural data. The task of obtaining from these micrographs the large quantity of data needed to get statistically valid results has been eased in two general ways. Sampling of data in the micrograph can be done rapidly by point and intersection counting methods. An alternate method, planimetry, obtains all the data in the micrograph, but in general is more time-consuming than point and intersection counting. Some of the relative inefficiency of planimetry is compensated when a digital planimeter is coupled with a computer. Areas and lengths can be computed simultaneously as fast as profiles are traced. Furthermore, rapid and numerically accurate compilation and statistical analysis of the data can be done automatically as the planimetry is done, not as a separate step after the data have been obtained.

A minicomputer-based package enabling determination of particle size distribution from sectional profile size distribution (Wicksell's correction)

Up to now a rather large computing system was needed to perform a Wicksell's correction, enabling the deduction of the distribution of corpuscle sizes from the distribution of the sizes of their transected p3ofiles. This paper describes the possibility to perform the same correction on a minicomputer with a free-access memory of only 8 kilobytes. A considerable time-saving may be obtained still by linking the minicomputer to a digital planimeter.

An Automatic Device for Measuring Leaf Area

Automatic planimeters described in the literature have, with one exception (Winter et al., 1956), been analogue devices measuring some continuously variable quantity (light interception, air flow) related to area. This system is simple in principle but elaborate precautions are required to eliminate errors arising from variations in mains voltage, non-linearity and fatigue of photo cells, stray light, contamination by mud from the leaves, non-uniformity of the light beam, and variations in leaf transmission. Some of these sources of errors are avoided by using air instead of light. Unfortunately, the airflow planimeter (Jenkins, 1959) is unsuitable for estimating large areas because of the great air flow required and because the null adjustment limits the speed of operation. In crop studies the total area of a number of leaves in a sample is usually of more interest than the individual values. Unfortunately, it is impossible to make an analogue device give the total of a series of determinations unless the information is first converted into digital form. A digital instrument has greater potentialities ; such a device would count the number of elements (unit areas) in the leaf, or series of leaves, and register the result. As the relation between counts and leaf area depends only on the size of the element, which is fixed by the dimensions of the instrument and the accuracy of the counting, it is independent of the sources of error mentioned above. These advantages are offset by the increased complexity of the system and it was decided to construct a digital planimeter suitable for sugar-beet as a test of the method. Manual methods based on this principle were described by Winter et al. (*956).