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PubMed1978

Errors in the assessment of pocket depth in vitro.

The inaccuracy of the calibration of two Merritt-B probes, old and new style, was investigated. It appeared that the calibration of the Merritt-B "new style" probe was better than the calibration of the old one. The influence of the mode of calibration and the reading of the calibration on pocket depth assessment with a Merritt-B "old style" probe was studied in an in vitro model. The model consisted of 32 aluminium cubes each with a hole in the centre. The holes were 1 mm in cross-section and the depth varied from 0.25 mm to 8 mm in 0.25-mm increments. Results show that pocket depths of 1 mm to 8 mm +/- 0.25 mm generally were read correctly about 90% of the time. This was not true for the 4- and 6-mm areas. When a probe was used where the 4- and 6-mm marks were omitted, pocket depth in that area were read correctly only in about 60% of instances. This difference disappeared when the 4- and 6-mm marks were added. Results of measuring the half millimeter values showed that generally 80% were recorded as the lower whole millimeter.

Dental Instruments↗

PubMed2004

Performance of DIAGNOdent for detection and quantification of smooth-surface caries in primary teeth.

OBJECTIVES: To evaluate the performance of the laser fluorescence device (DIAGNOdent) for detection and quantification of smooth-surface caries lesions in primary teeth. METHODS: Seventy-seven approximal surfaces with no caries or with white spot caries lesions without cavitation was selected from 51 primary molars. Laser fluorescence readings were performed and the site of higher value in each surface was indicated. After the readings, the surfaces were cut and the samples were destined for histopathological and cross-sectional microhardness evaluation. ROC analysis was conducted and the area under the ROC curve and the best cut-off points were obtained at D1, D2 and D3 thresholds. With these cut-off values, the sensitivity, specificity and accuracy were calculated at these thresholds. The regression lines of laser fluorescence readings as function of lesion extension, lesion depth and cross-sectional microhardness values were plotted and the Pearson correlation coefficients were obtained. RESULTS: The best DIAGNOdent performance was obtained at D3 threshold (A(z)=0.90) and the worst performance was achieved at D1 threshold (A(z)=0.82). The correlation was better between the laser fluorescence readings and lesion depth obtained in polarized light microscope examination (r=0.78), than that obtained with the microhardness values (r=-0.57). CONCLUSION: The laser fluorescence shows a good performance to predict caries lesions extension. Device presents a better correlation with the lesion depth than with mineral loss in smooth-surface caries lesions.

Child, Preschool↗

PubMed1992

Intraobserver and interobserver reproducibility of the Nidek EAS-1000 Anterior Eye Segment Analysis System.

The NIDEK EAS-1000 is a camera and computer system designed to facilitate measurement and analysis of the anterior segment of the eye. To evaluate the interobserver reproducibility of the system, three examiners assessed the anterior chamber depth and peripheral angle measurement in 20 disease-free eyes. Intraobserver reproducibility was determined by each investigator's photographing and analyzing the same eye on three different occasions. Interobserver correlation for the anterior chamber depth (using the first three readings of the same eye made by each examiner) was 0.97, with an 95% CI of 0.94 to 0.98. Interobserver correlation for angle measurement (again using the first three readings of the same eye made by each examiner) was 0.89, with a 95% confidence interval (CI) of 0.81 to 0.95. Intraobserver correlations for anterior chamber depth were 0.98 for each of the three examiners (mean, 0.98), wiht a 95% CI of 0.91 to 0.99. Intraobserver correlations for anterior chamber depth were 0.98 for each of the three examiners (mean, 0.98), with a 95% CI of 0.91 to 0.99. The intraobserver CI for angle measurement was 0.97 (range, 0.95 to 0.99). The intraobserver and interobserver reproducibility of the NIDEK EAS-1000 system was excellent.

Adult↗

PubMed1997

GPS signal reception under snow cover: a pilot study establishing the potential usefulness of GPS in avalanche search and rescue operations.

Avalanches are one of the major threats to life in high-mountain terrain and account every year for approximately 150 accidents causing injury or death in the United States alone. Every year avalanches cause significant property damages and a death toll of approximately 15 people in the United States. The specific characteristic of the avalanche accident is the extreme importance of getting to the buried victim as soon as, possible to improve survival. Approximately 40% of all buried victims survive 1 hour, and only about 20% survive 2 hours. Newer studies from Europe indicate that the initial survival probability is 92% at 15 minutes, 30% at 35 minutes, 27% at 90 minutes, and finally drops to 3% at 130 minutes. Unless prompt and efficient search and rescue are ensured, the prospect of buried victims is rather grim. Many tools have been used in the past to aid in retrieving buried victims including the avalanche cord, probing techniques, and in more recent time, the use of electronic beacon devices that allow search teams to locate the buried victim. The advent of satellite navigational aids (GPS, GLONASS) makes it possible to determine one's position with remarkable accuracy. We studied the degree to which the GPS satellite signal could penetrate through snow and be received by a commercially available GPS receiver. This information may lead to the development of an additional tool for precise and quick localization of buried victims in avalanche accidents and thus may substantially improve their survival by shortening the search time at the accident site. In this study we used a Motorola Traxar six-channel GPS receiver with amplifier unit connected to an antenna by means of a shielded coaxial cable. The antenna was buried under incremental covers of compact snow, and the reception of the GPS signal was measured at each burial depth: 5 cm, 15 cm, 25 cm, 35 cm, 45 cm, 55 cm, 1 m, and 1.5 m. The variables that were measured included signal quality, number of satellites received by the receiver, and their respective signal strength. A reference reading was taken from the GPS receiver above the testing site before measurements under snow cover were started. The satellite signals were received with good quality and precise readings up to a burial depth of 1 m. Under 1.5 m of snow the receiver was able to lock on only one satellite, making a positional reading impossible. The reception of the GPS signals under snow cover is possible and warrants further study directed toward the development of a search and rescue device using this technology.

Asphyxia↗

PubMedDate not supplied

Comparison of ion chamber and TLD dosimetry in mammography.

An ionization chamber method has been developed to measure exposure vs depth in a uniform BR 12 "average breast" phantom. It employs a Memorial mammography chamber for exit exposure measurements; resulting data is then corrected for backscatter as well as for the exceptionally thin window of this chamber. A careful comparison has then been made with relative exposure vs depth curves obtained using TLD at several mammography beam qualities, for identical exposure factors and SSD values. Use of a correction for residual and background TL signals significantly improved agreement between TLD and ion chamber curves in the 28 to 35 kVp/0.03 mm Mo range of beam quality. Agreement was within +/- 5% for the Mo target tube, but TLD readings were 4%--8% higher than ion chamber values for the W/Mo target tube. At Xeromammography energies (45 kVp/1.6 mm Al), corrected TLD curve readings were 6% higher at depth than ion chamber curve values. TLD meaurements with 28 to 35 kVp/0.03 mm Mo beams tend to underestimate dosage to the midbreast parenchyma. For example, in a 5 cm "average breast", the underestimation ranges from 2%--10% for corrected, 10%--16% for uncorrected TLD readings.

Female↗

PubMed2001

A directional dose equivalent monitor for neutrons.

A directional dose equivalent monitor is introduced which consists of a 30 cm diameter spherical phantom hosting a superheated drop detector embedded at a depth of 10 mm. The device relies on the similarity between the fluence response of neutron superheated drop detectors based on halocarbon-12 and the quality-factor-weighted kerma factor. This implies that these detectors can be used for in-phantom dosimetry and provide a direct reading of dose equivalent at depth. The directional dose equivalent monitor was characterised experimentally with fast neutron calibrations and numerically with Monte Carlo simulations. The fluence response was determined at angles of 0, 45, 90, 135 and 180 degrees for thermal to 20 MeV neutrons. The response of the device is closely proportional to the fluence-to-directional dose equivalent conversion coefficient, h'phi (10; alpha, E). Therefore, our monitor is suitable for a direct measurement of neutron directional dose equivalent, H'(10), regardless of angle and energy distribution of the neutron fluence.

Calibration↗

PubMed1984

Reliability of coding depth of approximal carious lesions from non-independent interpretation of serial bitewing radiographs.

In order to help understand the effectiveness of preventive care and the source of variation in treatment decisions, it is important to determine intra- and interexaminer agreement on the presence and depth of radiolucencies on bitewing radiographs when serial radiographs on individuals are available for interpretation. Serial radiographs on 24 subjects were read in succession, and one of four depth codes was assigned to approximal lesions. The radiographs were then read a second time, both by the person who had initially read the radiographs and by a second reader. Intraexaminer agreement on presence of a lesion ranged from 60% to 90%; four of the five readers had an agreement of over 78%. Interexaminer agreement on presence of a lesion ranged from 71% to 84%. Intraexaminer agreement on depth of lesion ranged from 64% to 80%; four readers had an agreement of over 73%. Interexaminer agreement on depth of lesion ranged from 59% to 76%.

Adolescent↗

PubMed2005

A case of awareness despite an "adequate depth of anesthesia" as indicated by a Bispectral Index monitor.

We report a case of awareness that occurred despite the presence of an "adequate" depth of anesthesia as measured by Bispectral Index. Our patient was at high risk for this complication. Hypotension limited the use of sevoflurane, and neuromuscular, sympathetic, and beta-adrenergic blockade prevented the patient from responding to his awareness. Preoperative use of opioids and gabapentin for chronic pain may have modified his response to anesthesia or affected his Bispectral Index reading. Our attempt to measure depth of anesthesia may have resulted in false reassurance concerning adequacy of anesthesia and contributed to awareness.

Anesthesia↗

PubMed1996

Visual properties of the foldable Array multifocal intraocular lens.

PURPOSE: To evaluate visual acuity, depth of focus, contrast sensitivity, and glare disability in eyes with an Array SSM 26-NB three-piece, five-zone multifocal intraocular lens (IOL). SETTING: University Eye Clinic, Vienna, Austria. METHOD: Fourteen eyes with an AMO Array IOL were evaluated for uncorrected and best corrected distance and near visual acuity. The reading distance produced by the near focus of the lens was varied with convex glasses of less power. Reading at distance focus was evaluated by adding +3.50 diopters (D) to the distance correction. Depth of focus was measured from -3.00 to +6.00 D. Contrast sensitivity and glare disability were also measured using the Brightness Acuity Tester with stationary sinusoidal gratings at 0.5, 1, 3, 6, 11.4, and 22.8 cycles/degree. RESULTS: Mean uncorrected distance acuity (Snellen) was 0.79 +/- 0.17 (SD), which increased to 0.94 +/- 0.14 with best correction. Near acuity was J2.75 +/- 1.35 and J2.59 +/- 1.10, respectively. When near focus was tested for reading distance, a mean of +0.54 +/- 0.02 D was accepted for improvement of near vision of J1.71 +/- 0.94. Near acuity with a distance focus addition of +3.50 D was J1.08 +/- 0.28. Contrast sensitivity and glare disability were lower than in 13 eyes with a monofocal poly(methyl methacrylate) IOL and 16 normal phakic eyes. CONCLUSIONS: Eyes with the Array IOL had full distance function. Reading performance could be improved with a near focus of more than +3.50 D. Full near vision could be achieved with the distance focus and conventional reading glasses. Depth of focus was sufficient but visual acuity was limited at intermediate and near distance. Although contrast sensitivity was relatively low, it was not beyond the reference range.

Aged↗

PubMed1985

Comparison of ionisation measurements in water and polystyrene for electron beam dosimetry.

For the determination of absorbed dose to water in electron beams, dosimetry protocols advocate ionisation measurements in plastic phantoms instead of water for practical reasons. The chamber readings in polystyrene at the depth of maximum ionisation must be corrected for the difference in physical properties between the two materials. This correction factor was determined for a Farmer 0.6 cm3 graphite-walled chamber in electron beams with mean energies at the phantom surface between 6 and 19 MeV. Experiments with white polystyrene yielded corrections for the measured ionisation ranging from 0.3 to 2.4%. For clear polystyrene, 0.6-1% higher corrections were found. For beams with the same mean energy at the phantom surface, but with different beam-flattening and collimation systems, variations in this correction up to 1.2% were observed. In contrast to recent reports on electrical charge storage in polystyrene due to electron irradiation, our experiments do not show differences in the chamber readings any larger than 0.5%.

Electrons↗

PubMed2004

In vivo validity and reliability of IR fluorescence measurements for caries detection and quantification.

Studies of detection and quantification of dental caries by KaVo DIAGNOdent have shown high diagnostic accuracy and high inter-operator agreement in vitro. The aim of the present study was to determine whether comparable results could be achieved under clinical conditions. In Part I (occlusal surfaces), 52 occlusal sites (suspected caries) were examined by visual inspection, bitewing radiography, and two DIAGNOdent devices. The fissures were then opened, and lesion depth established according to a four point scale. In Part II (smooth surfaces), two operators performed DIAGNOdent measurements of incipient carious lesions on the buccal surface of 30 molar teeth. The readings were compared with corresponding measurements by Quantitative Light-induced Fluorescence (deltaF). The results for occlusal surfaces disclosed very low correlation between lesion depth and readings by the two DIAGNOdent devices. The intra-operator agreements were very good (0.80-0.92), and the inter-operator agreement was good (0.71-0.87). A significant systematic difference in readings by the two devices precludes general recommendations of cut-off levels. However, individually suitable cut-off values for dentinal lesions gave good qualitative information about the surface (77%-85% over all correct observations), rather than quantitative information in terms of lesion depth within the dentine. In this context, the DIAGNOdent device might be of help for the clinician in the process of decision making about invasive therapy. For smooth surfaces, the correlation between readings obtained with the DIAGNOdent device and deltaF were acceptable (0.57-0.73). The intra-operator agreement was 0.94 for both operators (excellent), and the inter-operator agreement ranged from 0.79 to 0.87 (very good).

Adolescent↗

PubMed2004

Consistency of DIAGNOdent instruments for clinical assessment of fissure caries.

DIAGNOdent (KaVo, Biberach, Germany) has shown high diagnostic accuracy and intra-operator agreement for caries detection, both in vitro and in vivo. The aims of this study were to compare DIAGNOdent with visual examination (VI) and bitewing radiographs (BW) for clinical assessment of occlusal fissures, and to evaluate inter-device consistency of clinical recording using four different DIAGNOdent instruments; secondly, to correlate DIAGNOdent readings with microbial culture of the measured site. The subjects were young adults, the material comprising 34 occlusal fissures, scheduled for restorative treatment at the Dental School Clinic of the University of Iceland. Two examiners conducted visual and radiographic assessments. One examiner measured each site with four DIAGNOdent instruments in random order. The fissure was then opened and lesion depth was classified on a 4-point scale. Bacterial samples were taken from the fissure before and after opening. Intra-operator agreement was high (r = 0.85-0.98). Inter-device correlation for the four DIAGNOdent instruments was significant in all cases (r = 0.81-0.92). However, a common cut-off point could not be determined. There was weak but significant correlation between DIAGNOdent readings and all three classes of lesion depth. Level of infection showed very weak correlation with the DIAGNOdent readings. It was concluded that DIAGNOdent is more reliable in detecting dentinal caries if a proper cut-off point is used than in indicating actual lesion depth. Readings from the different instruments were not directly comparable, however, owing to the lack of a common cut-off point.

Adolescent↗

PubMed2026

The Oral Microbiome of King Richard III of England.

OBJECTIVES: Metagenomic investigations of ancient dental calculus provide insights into oral health, disease, and diet. Here, we analyze the dental calculus metagenome of King Richard III of England (1452-1485). MATERIALS AND METHODS: Dental calculus DNA was extracted from three teeth of King Richard III and shotgun sequenced to a depth of nearly 400 million reads. The metagenomic data were taxonomically profiled and compared to new and previously published dental calculus metagenomes from England, Ireland, the Netherlands, and Germany spanning the Neolithic to the present. Sequencing data were de novo assembled, and metagenome-assembled genomes assigned to the genus Tannerella were investigated for phylogenetic relatedness and virulence. Putative dietary DNA was assessed for authenticity. RESULTS: The dental calculus of King Richard III was well-preserved and yielded an exceptionally high quantity of DNA. Oral microbiome species diversity fell within the range previously observed among other northern European populations, suggesting that a royal lifestyle and a rich diet did not substantially impact his oral microbiota. The reconstructed Tannerella genomes contained many virulence factors found today among oral Tannerella species. No putative dietary DNA could be authenticated. DISCUSSION: The dental calculus of King Richard III produced one of the richest ancient oral metagenomes published to date, yet the species diversity was indistinguishable from that of commoners living in northern Europe over the last 7000 years. Insufficient plant and animal DNA were recovered to investigate diet, suggesting that dental calculus may not be a sufficient source of dietary DNA even when exceptionally well-preserved.

Humans↗

PubMed1984

Pyramidal neurones of the dorsal cochlear nucleus: a Golgi and computer reconstruction study in cat.

The main projection neurones of the dorsal cochlear nucleus, termed pyramidal, bipolar or fusiform cells, have an apical dendritic arbor approaching the ependymal surface of the nucleus and a basal arbor oppositely directed. In Golgi-Del Rio-Hortega material these neurones were studied, with the light microscope, in nonconventional planes of sectioning oriented across or parallel to the main axis of the elongated nucleus. The pyramidal neurones were seen to be flattened across this axis. The size, shape and orientation of 21 cells from six blocks were studied in detail with computer-aided graphic reconstructions including stereo views. Camera lucida drawings of each cell (usually from several sections) were digitized to obtain x and y coordinates while z coordinates (depths in the tissue) were read from the fine focus knob during microscopy and typed interactively during digitization. The z values were corrected for the effects of refractive index differences in the optical system. Since it was the aim of this study to focus on some fundamental principles of structure and arrangement of pyramidal cells in the dorsal cochlear nucleus rather than on topographic variations, only the middle, regularly built part of the nucleus was examined. Towards the ends of the nucleus the architecture is less regular and will require separate analysis. Measurements of arbor and total cell height and of dendritic length are given. The height of the apical and basal arbor in individual cells showed considerable reciprocity. The total dendritic length was up to 8300 micron (average 6536 micron). The basal arbors always proved to be conspicuously flattened; roughly, the width varied between about 300 and 700 micron (average 489 micron) and the thickness between 65 and 105 micron (average 80 micron). The apical arbors were also often flattened but much less and with a greater variability than the basal arbors (average width 319 micron, thickness 115 micron). The two arbors of individual cells were practically coplanar, the arbor planes showing only moderate angularity (bend) and/or torsion relative to each other (angularity maximum 10 degrees, average 5 degrees; torsion maximum 18 degrees, average 6 degrees). The mutual orientation of cells from the same block was examined. The planes through the basal arbors proved to be very parallel, the differences in orientation angles being between 10 and 0 degrees with rare exceptions. Clearly flattened, apical arbors showed a somewhat greater spread.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2025

Development and extensive sequencing of a broadly-consented Genome in a Bottle matched tumor-normal pair.

The Genome in a Bottle Consortium (GIAB), hosted by the National Institute of Standards and Technology (NIST), is developing new matched tumor-normal samples, the first explicitly consented for public dissemination of genomic data and cell lines. Here, we describe a comprehensive genomic dataset from the first individual, HG008, including DNA from an adherent, epithelial-like pancreatic ductal adenocarcinoma (PDAC) tumor cell line and matched normal cells from duodenal and pancreatic tissues. Data for the tumor-normal matched samples comes from seventeen distinct state-of-the-art whole genome measurement technologies, including high depth short and long-read bulk whole genome sequencing (WGS), single cell WGS, Hi-C, and karyotyping. These data will be used by the GIAB Consortium to develop matched tumor-normal benchmarks for somatic variant detection. We expect these data to facilitate innovation for whole genome measurement technologies, de novo assembly of tumor and normal genomes, and bioinformatic tools to identify small and structural somatic variants. This first-of-its-kind broadly consented open-access resource will facilitate further understanding of sequencing methods used for cancer biology.

Humans↗

PubMed1999

Sleep studies based on electroencephalogram energy analysis.

Current sleep studies use the manual polysomnographic technique or frequency analysis when investigating the mechanisms behind the incomplete transition from sleep to consciousness. Ten control subjects and 11 primary monosymptomatic enuretics were studied in a sleep laboratory for three consecutive nights (23.00-07.00 h). The results showed no significant differences in sleeping pattern between enuretics and controls. Enuretics spent more time in stage 3 sleep than controls on recovery nights, indicating greater depth of sleep. No differences in sleep architecture were noted between the groups on baseline nights, although enuretics showed a shorter total sleep period than controls on the recovery night. Increased delta waves exhibited in the enuretic group are indicative of a greater depth of sleep. Moreover, electroencephalogram readings showed an impaired arousal in enuretics, which suggests that sleep may be a part of the pathology of enuresis.

Adult↗

PubMed1975

Effects of hyperbaric air pressure on keratometry.

Following reports of vision blur by scuba divers at depth below 100 feet, keratometric readings were taken on volunteers inside a hyperbaric chamber at the USAF School of Aerospace Medicine. It was found that as the pressure within the chamber increased, the corneal reading showed an increased dioptric value. This change in refractive condition also occurred in measurement on test steel balls. Whether this dynamic response was due to increased atmospheric index, or displacement of instrument optics, was explored.

Air Pressure↗

PubMed2025

Development and extensive sequencing of a broadly-consented Genome in a Bottle matched tumor-normal pair.

The Genome in a Bottle Consortium (GIAB), hosted by the National Institute of Standards and Technology (NIST), is developing new matched tumor-normal samples, the first to be explicitly consented for public dissemination of genomic data and cell lines. Here, we describe a comprehensive genomic dataset from the first individual, HG008, including DNA from an adherent, epithelial-like pancreatic ductal adenocarcinoma (PDAC) tumor cell line and matched normal cells from duodenal and pancreatic tissues. Data for the tumor-normal matched samples comes from seventeen distinct state-of-the-art whole genome measurement technologies, including high depth short and long-read bulk whole genome sequencing (WGS), single cell WGS, and Hi-C, and karyotyping. In future publications, these data will be used by the GIAB Consortium to develop matched tumor-normal benchmarks for somatic variant detection. We expect these data to facilitate innovation for whole genome measurement technologies, de novo assembly of tumor and normal genomes, and bioinformatic tools to identify small and structural somatic mutations. This first-of-its-kind broadly consented open-access resource will facilitate further understanding of sequencing methods used for cancer biology.

Journal Article↗