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Bowman DC, Rouse JW, Krishnamoorthy S, Silber EA. Infrasound direction of arrival determination using a balloon-borne aeroseismometer. JASA Express Lett 2022; 2:054001. [PMID: 36154067 DOI: 10.1121/10.0010378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Free-floating balloons are an emerging platform for infrasound recording, but they cannot host arrays sufficiently wide for multi-sensor acoustic direction finding techniques. Because infrasound waves are longitudinal, the balloon motion in response to acoustic loading can be used to determine the signal azimuth. This technique, called "aeroseismometry," permits sparse balloon-borne networks to geolocate acoustic sources. This is demonstrated by using an aeroseismometer on a stratospheric balloon to measure the direction of arrival of acoustic waves from successive ground chemical explosions. A geolocation algorithm adapted from hydroacoustics is then used to calculate the location of the explosions.
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Affiliation(s)
- Daniel C Bowman
- Geophysical Detection Systems, Sandia National Laboratories, Albuquerque, New Mexico, 87123, USA
| | - Jerry W Rouse
- Analytical Structural Dynamics, Sandia National Laboratories, Albuquerque, New Mexico, 87123, USA
| | | | - Elizabeth A Silber
- Geophysics, Sandia National Laboratories, Albuquerque, New Mexico, 87123, USA , , ,
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Brissaud Q, Krishnamoorthy S, Jackson JM, Bowman DC, Komjathy A, Cutts JA, Zhan Z, Pauken MT, Izraelevitz JS, Walsh GJ. The First Detection of an Earthquake From a Balloon Using Its Acoustic Signature. Geophys Res Lett 2021; 48:e2021GL093013. [PMID: 34433991 PMCID: PMC8365762 DOI: 10.1029/2021gl093013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/20/2021] [Accepted: 04/23/2021] [Indexed: 06/13/2023]
Abstract
Extreme temperature and pressure conditions on the surface of Venus present formidable technological challenges against performing ground-based seismology. Efficient coupling between the Venusian atmosphere and the solid planet theoretically allows the study of seismically generated acoustic waves using balloons in the upper atmosphere, where conditions are far more clement. However, earthquake detection from a balloon has never been demonstrated. We present the first detection of an earthquake from a balloon-borne microbarometer near Ridgecrest, CA in July 2019 and include a detailed analysis of the dependence of seismic infrasound, as measured from a balloon on earthquake source parameters, topography, and crustal and atmospheric structure. Our comprehensive analysis of seismo-acoustic phenomenology demonstrates that seismic activity is detectable from a high-altitude platform on Earth, and that Rayleigh wave-induced infrasound can be used to constrain subsurface velocities, paving the way for the detection and characterization of such signals on Venus.
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Affiliation(s)
- Quentin Brissaud
- Seismological LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
- the Norwegian Seismic Array (NORSAR)OsloNorway
| | | | | | | | - Attila Komjathy
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - James A. Cutts
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Zhongwen Zhan
- Seismological LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | - Michael T. Pauken
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
| | | | - Gerald J. Walsh
- Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaCAUSA
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Bird EJ, Bowman DC, Seastrand DR, Wright MA, Lees JM, Dannemann Dugick FK. Monitoring changes in human activity during the COVID-19 shutdown in Las Vegas using infrasound microbarometers. J Acoust Soc Am 2021; 149:1796. [PMID: 33765803 PMCID: PMC8023270 DOI: 10.1121/10.0003777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
While studies of urban acoustics are typically restricted to the audio range, anthropogenic activity also generates infrasound (<20 Hz, roughly at the lower end of the range of human hearing). Shutdowns related to the COVID-19 pandemic unintentionally created ideal conditions for the study of urban infrasound and low frequency audio (20-500 Hz), as closures reduced human-generated ambient noise, while natural signals remained relatively unaffected. An array of infrasound sensors deployed in Las Vegas, NV, provides data for a case study in monitoring human activity during the pandemic through urban acoustics. The array records a sharp decline in acoustic power following the temporary shutdown of businesses deemed nonessential by the state of Nevada. This decline varies spatially across the array, with stations close to McCarran International Airport generally recording the greatest declines in acoustic power. Further, declines in acoustic power fluctuate with the time of day. As only signals associated with anthropogenic activity are expected to decline, this gives a rough indication of periodicities in urban acoustics throughout Las Vegas. The results of this study reflect the city's response to the pandemic and suggest spatiotemporal trends in acoustics outside of shutdowns.
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Affiliation(s)
- Elijah J Bird
- Geophysical Detection Programs, Sandia National Laboratories, 1515 Eubank Southeast, MS 0404, Albuquerque, New Mexico 87123, USA
| | - Daniel C Bowman
- Geophysical Detection Programs, Sandia National Laboratories, 1515 Eubank Southeast, MS 0404, Albuquerque, New Mexico 87123, USA
| | - Douglas R Seastrand
- Advanced Technologies Division, Nevada National Security Site, P.O. Box 98521, Las Vegas, Nevada 89193-8521, USA
| | - Melissa A Wright
- Nevada National Security Site, P.O. Box 98521, Las Vegas, Nevada 89193-8521, USA
| | - Jonathan M Lees
- Department of Geological Sciences, 104 South Road, CB #3315, University of North Carolina, Chapel Hill, North Carolina 27599-3315, USA
| | - Fransiska K Dannemann Dugick
- Geophysical Detection Programs, Sandia National Laboratories, 1515 Eubank Southeast, MS 0404, Albuquerque, New Mexico 87123, USA
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Krishnamoorthy S, Bowman DC, Komjathy A, Pauken MT, Cutts JA. Origin and mitigation of wind noise on balloon-borne infrasound microbarometers. J Acoust Soc Am 2020; 148:2361. [PMID: 33138515 DOI: 10.1121/10.0002356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 10/07/2020] [Indexed: 06/11/2023]
Abstract
High-altitude monitoring of low-frequency acoustic waves (infrasound) on Earth has regained prominence in recent years, primarily driven by improvements in light-weight sensor technology and advances in scientific ballooning techniques. Balloon-borne infrasound monitoring is also being proposed as a remote sensing technique for planetary exploration. Contrary to ground-based infrasound monitoring, the infrasound noise background in the stratosphere as measured by a balloon remains uncharacterized and the efficacy of wind noise mitigation filters has not been investigated. In this study, an analysis of pressure data collected using infrasound microbarometers during the flight of a long-duration zero pressure balloon is presented. A dramatic reduction of background noise in the stratosphere is demonstrated and it is shown that wind noise mitigation filters are not effective at reducing wind noise under these conditions. Results from this study demonstrate stratospheric balloons as a low-noise platform for infrasound monitoring and motivate the development of improved noise mitigation tools.
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Affiliation(s)
- Siddharth Krishnamoorthy
- National Aeronautics and Space Administration Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - Daniel C Bowman
- Sandia National Laboratories, Albuquerque, New Mexico 87123, USA
| | - Attila Komjathy
- National Aeronautics and Space Administration Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - Michael T Pauken
- National Aeronautics and Space Administration Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - James A Cutts
- National Aeronautics and Space Administration Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
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Cramer GR, Bowman DC. Short-term leaf elongation kinetics of maize in response to salinity are independent of the root. Plant Physiol 1991; 95:965-7. [PMID: 16668080 PMCID: PMC1077632 DOI: 10.1104/pp.95.3.965] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The essentiality of roots to the short-term responses of leaf elongation to salinity was tested by removing the roots of maize (Zea mays L.) from the shoots and comparing the initial short-term response of leaf elongation to that with intact plants. Eightday-old seedlings growing in solution culture were treated with 80 millimolar NaCl and their leaf elongation rate (LER) was monitored with a linear variable differential transformer connected to a computerized data aquisition system. Initially, LER of intact plants was sharply reduced by salinity, then rose rapidly to reach a new steady-state rate about 1.5 hours after salinization. The new steady-state rate of salinized intact plants was about 80% of the control rate. When the roots of nonsalinized plants were excised under the surface of the nutrient solution, excision did not disturb the steady-state LER. When these shoots were salinized, they responded in a manner nearly identical to that of intact plants, indicating that roots are not essential for the modulation of short-term LER of salt-stressed plants.
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Affiliation(s)
- G R Cramer
- Department of Plant Science, University of Nevada, Reno, Nevada 89557
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Abstract
Free amino acids and indoles were measured by HPLC in single pineal glands of 5-, 10- and 20-day-old rats sacrificed during mid-light and mid-dark at each age. Melatonin was detectable in neonates (5-day-old), but day vs night differences in indole constituents did not occur until 10 days of age. Free amino acid steady state levels were high in neonates and there was a tendency for reversal of day vs night differences coinciding with the onset of circadian rhythmicity in indole biosynthesis. High correlations (r greater than 0.85) existed for taurine vs. glutamate in individual glands regardless of age and time of sacrifice. These findings suggest that taurine and glutamate are biochemically interrelated and that developmental changes in amino acid metabolic pools reflect functional innervation of the gland.
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Affiliation(s)
- J A McNulty
- Department of Anatomy, Loyola University School of Medicine, Maywood, Illinois 60153
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Abstract
Assimilation of NO(3) (-) and NH(4) (+) by perennial ryegrass (Lolium perenne L.) turf, previously deprived of N for 7 days, was examined. Nitrogen uptake rate was increased up to four- to five-fold for both forms of N by N-deprivation as compared to N-sufficient controls, with the deficiency-enhanced N absorption persisting through a 48 hour uptake period. Nitrate, but not NH(4) (+), accumulated in the roots and to a lesser degree in shoots. By 48 hours, 53% of the absorbed NO(3) (-) had been reduced, whereas 97% of the NH(4) (+) had been assimilated. During the early stages (0 to 8 hours) of NO(3) (-) uptake by N-deficient turf, reduction occurred primarily in the roots. Between 8 and 16 hours, however, the site of reduction shifted to the shoots. Nitrogen form did not affect partitioning of the absorbed N between roots (40%) and shoots (60%) but did affect growth. Compared to NO(3) (-), NH(4) (+) uptake inhibited root, but not shoot, growth. Total soluble carbohydrates decreased in both roots and shoots during the uptake period, principally the result of fructan metabolism. Ammonium uptake resulted in greater total depletion of soluble carbohydrates in the root compared to NO(3) (-) uptake. The data indicate that N assimilation by ryegrass turf utilizes stored sugars but is also dependent on current photosynthate.
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Affiliation(s)
- D C Bowman
- Department of Environmental Horticulture, University of California, Davis, California 95616
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Abstract
This study describes intercellular bridges in the ovaries of neonatal gerbils. Electron microscopy has revealed the presence of true intercellular bridges, connecting oogonia or oocytes, in ovaries of newborn gerbils. The cytoplasm of the intercellular channels is similar to that of the connected cells, with mitochondria, smooth and rough endoplasmic reticulum, and free ribosomes present. Lysosomes are also occasionally present in the intercellular bridges and they may be involved in early waves of oocyte atresia. An electron-dense substance, 350-500 A thick, is located immediately beneath the unit membrane of the intercellular bridges. Accumulation of electron-dense material increases the thickness of the walls of the intercellular bridges, supporting and maintaining the patency of the channels. It is suggested that the intercellular channels probably allow the interchange of nutrients, organelles, and possibly regulatory materials as well.
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Young AT, Malone WF, Toto PD, Bowman DC. Healing of mucoperiosteal incisions made by electrosurgery. Quintessence Int Dent Dig 1983; 14:973-9. [PMID: 6580671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Blanchet LJ, Bowman DC, McReynolds HD. Effects of methyl methacrylate monomer vapors on respiration and circulation in unanesthetized rats. J Prosthet Dent 1982; 48:344-8. [PMID: 6956729 DOI: 10.1016/0022-3913(82)90026-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A study was conducted in which two groups of female rats were exposed to vaporized MMA-m for a period of 20 minutes daily for 21 and 42 days, respectively. Systolic blood pressure, heart rate, respiration, and ECG were monitored for 5 minutes prior to MMA-m exposure and then during a 20-minute exposure to MMA-m. On the twenty-first and forty-second day, respectively, the aforementioned vectors were monitored again. During the first exposure 63% of the experimental animals displayed marked changes in respiration ranging from a modified Cheyne-Stokes type to periods of very shallow breathing followed by deep breathing. Thirty-eight percent showed ECG changes ranging from premature ventricular contractions and altered QRS complexes to markedly depressed T waves. Continued exposure resulted in an initial decrease followed by an increased systolic blood pressure with an increased respiratory and heart rate. At the final testing period all animals showed abnormal respiratory patterns and ECG changes and demonstrated a heart block pattern. In all animals systolic blood pressure increased the longer they were exposed to MMA-m.
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Doemling DB, Bowman DC. Laboratory grouping based on previous courses. J Dent Educ 1981; 45:797-800. [PMID: 6947001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In the human physiology course at Loyola University School of Dentistry, students (N = 761, second-year classes from 1971 to 1976) were divided into three laboratory groups according to prior experience with physiology courses and laboratories. To determine the effects of this grouping on academic performance, data were obtained on grades in the physiology course, National Board scores in physiology (combined with biochemistry from 1973 to 1976), predental GPA, and predental science GPA. Comparisons were made between the three groups using t-tests, and correlation coefficients were obtained for physiology grade and National Board score, predental GPA, and predental science GPA. The results indicated that there were no significant differences among the three groups in performance in the physiology course or on the National Board Examination. Significant correlations were found between course performance and the other three variables. The overall impression of the faculty and the students was that the grouping program has been successful in improving laboratory performance and participation in the conference sessions.
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Doemling DB, Bowman DC. Laboratory grouping based on previous courses. J Dent Educ 1981. [DOI: 10.1002/j.0022-0337.1981.45.12.tb01522.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bowman DC, Blanchet LJ, Doemling DB. Temporary auditory threshold shift following sophomore operative technique laboratory. J Dent Educ 1980; 44:261-3. [PMID: 6988480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Twenty sophomore dental students were studied for the "temporary threshold shift" (TTS) due to exposure to the noise of high-speed dental headpieces during technique laboratory sessions. TTS was experienced at all four frequencies tested--8000, 6000, 4000, and 3000 hertz, but tended to be greater and of longer duration at the higher frequencies. Approximately one-fourth of the students still had some hearing loss 15 minutes after leaving the laboratory.
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Abstract
A study was conducted on subjects with conventional dentures and with overlay dentures to compare their abilities to discriminate between occlusal forces. Perpendicular forces were applied to the dynamic center of the occlusal table of the mandibular denture. Each subject's ability to distinguish differences in values of force was observed and recorded. All subjects with dentures showed sensory threshold values close to those reported for natural teeth. A graphic plotting showed that the responses of subjects with overlay-type dentures were more closely correlated with the psychophysical law as expressed by Stevens as a power function. Since this phenomenon holds true for natural teeth, the overlay denture more closely resembles natural teeth in this type of sensory function than does the conventional denture. In addition to recognized advantages, such as preservation of the ridge and improved retention and stability, the overlay denture provides more typical sensory function than is provided by the conventional denture. This advantage should further motivate dentists and patients to consider the retention and utilization of at least two suitable teeth in an overlay-type denture service.
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Wood NK, Marks AD, Schmitz DD, Bowman DC, Toto PD. Radioautographic labeling in placentas and fetal palatal shelves after maternal injections of tritiated cortisone in A-Jax mice. J Dent Res 1972; 51:67-70. [PMID: 4500436 DOI: 10.1177/00220345720510013101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Tritiated cortisone was injected into pregnant A/Jax mice after a loading dose of cortisone on day 12 of pregnancy. Radioautographic studies of 160 placentas and fetal palatal shelves revealed: (1) significant labeling in all placental and fetal palatal tissue; (2) a variation in degree of labeling of fetal palates from different mothers; (3) no variation of degree of labeling in proximal or distal fetuses; and (4) a positive correlation in the degree of labeling in corresponding placentas and shelves.
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Soltis JE, Nakfoor PR, Bowman DC. Changes in ability of patients to differentiate intensity of forces applied to maxillary central incisors during orthodontic treatment. J Dent Res 1971; 50:590-6. [PMID: 5280575 DOI: 10.1177/00220345710500031101] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Changes in the subjective ability of patients undergoing orthodontic treatment to distinguish differences in intensity of forces applied to maxillary central incisors were evaluated. A decided reduction of this discriminatory ability was recorded four days after the insertion of orthodontic appliances. A significant reduction in pain threshold to these forces also was noted. Subsequent measurements showed a definite trend toward the initial pretreatment values.
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Abstract
Subjective ability to discriminate differences in intensity of forces applied to maxillary canines, and to mandibular incisors, canines, and first premolars was evaluated. Least relative differences in force could be discriminated through the maxillary canines (8.6 to 9.5%). Individuals showed nearly the same discriminatory ability for all mandibular teeth tested.
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Bowman DC, Rapp GW. A core course in oral biology for dental graduate educational programs. J Dent Educ 1968; 32:465-7. [PMID: 5247061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Bowman DC, Rapp GW. A core course in oral biology for dental graduate educational programs. J Dent Educ 1968. [DOI: 10.1002/j.0022-0337.1968.32.4.tb00134.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Ardoin WH, Merg FR, Bowman DC. Changes in tension of the masseter and digastric muscles of cats under stimuli. J Dent Res 1968; 47:1187. [PMID: 5249056 DOI: 10.1177/00220345680470063301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Bowman DC, Nakfoor PM. Evaluation of the human subject's ability to differentiate intensity of forces applied to the maxillary central incisors. J Dent Res 1968; 47:252-9. [PMID: 5238758 DOI: 10.1177/00220345680470021001] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Minimal detectable differences between two centered forces applied to maxillary central incisors were determined for 50 subjects. The forces involved were 10, 50, 100, 200, 500, and 1,000 gm; most accurate subjective discrimination was between the 50- and 500-gm centered forces. Incisally and labially directed forces yielded nearly identical results.
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Bowman DC, Blanchet LJ, Doemling DB, Harris SC. Effect of cortisone and salicylate on dissemination of cyanide and P32 from inflamed areas in rats and mice. J Oral Ther Pharmacol 1967; 4:25-31. [PMID: 6053763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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